Browse Topic: Kinematics

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Design Exploration of Airfoils for Rotorcraft Applications under Dynamic ConditionsF-0081-2025-01155/20/2025
This paper explores novel airfoils for rotorcraft applications using a gradient-free, multi-objective genetic algorithm with 2D URANS simulations. The study considers dynamic kinematics at a Reynolds number of 5×105 and a mean Mach number of 0.35. Two optimization scenarios are analyzed: 1) pre-stall kinematics (0° ≤α ≤10°) and 2) dynamic stall kinematics (0° ≤ α ≤ 20°). The paper compares two objective functions: f1, based on the cycle averaged lift, and ˜ f1, which modifies f1 by penalizing hysteresis in the lift coefficient. The effects of uniform vs. fluctuating freestream velocity and reduced frequency on optimal airfoils are also discussed. The proposed optimization approach has resulted in novel airfoil shapes that are characterized by a drooped nose, with a convex surface on the aft upper surface similar to a reflex camber in pre-stall kinematics and less unsteadiness in the air loads for the optimized airfoils under the dynamic stall kinematics.
Badrya, Camli
Exploring the Connection between Leading-Edge Suction and Dynamic Stall on Rotors in Forward Flight using Computational ResultsF-0080-2024-12385/7/2024
Dynamic stall continues to be a limiting factor for rotorcraft performance in forward flight. The complex flow physics, resulting from blade kinematics, aeroelastic deformations, and blade-vortex interactions, makes this problem challenging. The availability of results from recent high-fidelity coupled computational aerodynamics-structural dynamics simulations provides an opportunity to gain new insights into the physics of dynamic stall on rotor blades in realistic operating conditions. Recent research efforts have also resulted in the identification of a leading-edge suction parameter (LESP), whose critical value has been shown to correlate with the flow events leading to dynamic stall. Critical LESP is largely independent of motion parameters, and is dependent mostly on the airfoil shape, Reynolds number, and Mach number. In this work, LESP variation along the blades of a UH-60A rotor in forward flight is extracted from high-fidelity computational results. The objective is to explore the correlation between criticality of LESP and the onset of dynamic stall in a complex rotor flow. The results show a high correlation between LESP behavior and the signatures for the different occurrences of dynamic stall on the rotor blades. This excellent correlation provides the impetus for further application of the LESP concept to rotor aerodynamics.
Lee, Yi Tsung, Gopalarathnam, Ashok, Jain, Rohit, Yeh, Chi-An
Analyzing Mechanical Systems Using 3DX Design Tables, Kinematic Simulations, and Dynamic SimulationsF-0079-2023-179995/16/2023
Faysash, Jack
Development of a Non-Parametric Robot Calibration Method to Improve Drilling Accuracy2021-01-00033/2/2021
The drilling of large quantities of repetitive holes during the manufacture of large aerospace components is often considered a key limiting factor with regards to production efficiency. Whilst the desire within aerospace is to use relatively cheap six axis robot arms with drilling end effector units, their poor accuracy remains an obstacle. Robot calibration presents a way of improving robot accuracy such that aerospace drilling tolerances can be met, without permanently committing metrology equipment to an automation cell during production. Extensive research has been conducted into robot calibration by correcting the kinematic model, known as parametric calibration. This method is highly complex, and calibrates the robot across the entire working volume. This is often not required in industrial drilling applications, as drilling routines are often contained within a smaller volume of the robot reach. In this paper, a non-parametric method of robot calibration is proposed. This method involves calibrating within regions of the working volume where the robot pose is similar, and thus the effects of geometric errors in the kinematic model are roughly constant. By establishing the average positional error for each region, the accuracy can be locally improved by compensation through definition of the tool centre point. The proposed method can be completed without the use of kinematic models or complex mathematics, making it more suitable to industrial users. From experimental trials, a significant improvement in the positional accuracy of holes drilled using a standard six axis robot is reported, from 2 mm to 0.1 mm, well within the requirements of the majority of aerospace applications.
Scraggs, Chris, Smith, Thomas, Sawyer, Daniela, Davis, Matthew
Driver Drowsiness and Fatigue in the Safe Operation of Vehicles - Definition of Terms and ConceptsJ3198_202010 (Current)10/26/2020
This SAE Information Report provides definitions and discussions of key terms concerning driver drowsiness and fatigue, and basic information on measuring drowsiness and fatigue. It also includes information and concepts for driver drowsiness as they relate to the safe operation of a vehicle. The key driver drowsiness and fatigue causal factors include the following: (1) sleep quality and quantity, (2) time of day, (3) time awake, (4) time on task (modulated by characteristics of the driving task), (5) task-related fatigue (variations of arousal levels related to task underload and overload), and (6) combinations of these factors. Medical conditions, medication, alcohol, or drugs exacerbate drowsiness; however, the discussion in this report is limited to fatigue concepts. This report has two primary outputs: (1) definitions and discussions of key terms concerning driver drowsiness and fatigue, and (2) basic information on measuring drowsiness and fatigue and its effects on the safe operation of a vehicle. These include the physiological and cognitive effects of driver drowsiness and fatigue on driving safety. Examples of effect of driver drowsiness and fatigue on driving safety include those related to vehicle control, operator vigilance (sustained attention), reaction times (object and event detection and response), situational awareness, physiological indicators, subjective assessments, and combinations thereof. For definitions of driving performance measures, refer to SAE J2944. This report applies to all worldwide motor vehicle passenger cars and light trucks, as well as heavy trucks, buses, motorcycles, and mopeds. The intended users of the document are practitioners and researchers in the automotive industry, academia, and other organizations with interest in driver drowsiness and fatigue, driving and driver performance assessment, and road safety.
Driver Metrics, Performance, Behaviors and States Committee
Deep-Learned E-Skin Decodes Complex Human MotionTBMG-373518/1/2020
A deep-learning powered single-strained electronic skin sensor can capture human motion from a distance. The single strain sensor placed on the wrist decodes complex five-finger motions in real time with a virtual 3D hand that mirrors the original motions. The deep neural network boosted by rapid situation learning (RSL) ensures stable operation regardless of its position on the surface of the skin.
A Study of Driver's Driving Concentration Based on Computer Vision Technology2020-01-05724/14/2020
Driving safety is an eternal theme of the transportation industry. In recent years, with the rapid growth of car ownership, traffic accidents have become more frequent, and the harm it brings to human society has become increasingly serious. In this context, car safety assisted driving technology has received widespread attention. As an effective means to reduce traffic accidents and reduce accident losses, it has become the research frontier in the field of traffic engineering and represents the trend of future vehicle development. However, there are still many technical problems that need to be solved. With the continuous development of computer vision technology, face detection technology has become more and more mature, and applications have become more and more extensive. This article will use the face detection technology to detect the driver's face, and then analyze the changes in driver's driving focus. Firstly, the problem of detecting the eyes and mouth status of the driver is discussed. The purpose is to capture the driver's long-term closed eyes and yawning and other actions closely related to the dozing behavior. Secondly, the problem of estimating the driver's head posture is studied. The purpose is to capture the abnormal movements of the driver's long bow, head up or frequent nodding. The study consists of three parts: detection of facial feature points, estimation of the head posture based on the feature points, and definition of fatigue characteristics. The experimental results show that the method in this paper is not only easy to operate but also has a high accuracy rate for the detection of driver concentration.
Lin, Guan, Zhan, Zhenfei, Peng, Xiangjun, Xu, Huijie, Fu, Yue, Jiang, Ling
Human Response and Injury Resulting from Head Impacts with Unmanned Aircraft Systems2019-22-00023/31/2020
Unmanned aircraft systems (UAS), commonly known as drones, are part of a new and budding industry in the United States. Economic and public benefits associated with UAS use across multiple commercial sectors are driving new regulations which alter the stringent laws currently restricting UAS flights over people. As new regulations are enacted and more UAS populate the national airspace, there is a need to both understand and quantify the risk associated with UAS impacts with the uninvolved public. The purpose of this study was to investigate the biomechanical response and injury outcomes of Post Mortem Human Surrogates (PMHS) subjected to UAS head impacts. For this work, PMHS were tested with differing UAS vehicles at multiple impact angles, locations and speeds. Using a custom designed launching device, UAS vehicles were accelerated into the frontal, parietal, or vertex portions of subjects’ craniums at speeds up to 22 m/s. Of the 35 UAS impacts carried out, one AIS 2+ injury was observed: a 13 cm linear skull fracture resulting from a Phantom 3 impact. Additionally, injury risk curves used in automotive testing were found to over predict the risk of injury in UAS impact scenarios. Finally, localized skull deformation was observed during severe impacts; the effect that this deformation had on measured kinematics should be further evaluated. Overall, the study found that AIS 2+ head injuries may occur as a result of UAS impacts and that automotive injury metrics may not be able to accurately predict head injury risk in UAS impact scenarios.
Stark, David B., Willis, Arrianna K., Eshelman, Zach, Kang, Yun-Seok, Ramachandra, Rakshit, Bolte IV, John H., McCrink, Matthew
The Effect of An Acoustic Startling Warning On Take-Over Reaction Time And Trunk Kinematics for Drivers in Autonomous Driving Scenarios2019-22-00223/31/2020
The Acoustic Startling Pre-stimulus (ASPS, i.e. a loud sound preceding a physical perturbation) was previously found to accelerate action execution in simple flexion exercises. Therefore in this study we examined if ASPS can accelerate take-over reaction times in restrained teen and adult drivers who were asked to reach for the steering wheel while experiencing sled lateral perturbations simulating a vehicle swerve. Results showed that adult drivers lift their hands toward the steering wheel faster with the ASPS versus without (161 ± 23 ms vs 216 ± 27 ms, p<0.003). However this effect was not found in teens or in trials where the drivers were engaged in a secondary task. Adults also showed reduced lateral trunk displacement out of the seat belt with the ASPS. The ASPS could represent a novel warning that reduces take over time and out-of-position movements in critical autonomous driving scenarios.
Graci, Valentina, Griffith, Madeline, Maheshwari, Jalaj, Akkem, Rahul, Austin, Meta, Seacrist, Thomas, Arbogast, Kristy B.
Head Support Concept to Mitigate Neck Injury for Children Installed Forward Facing in Vehicles2019-36-01061/13/2020
The slender neck of a 3-year-old child can be serious injured or even lead to child’s death when loaded under frontal impact by the proportionately larger and heavier head. Accordingly with medical recommendations based on latest studies, a 3-year-old child is safer when installed in a rear-facing child seat, but this configuration is not feasible for some vehicles with limited rear space such as superminis, small MPVs and pick-ups when front seats are occupied. This study aims to explore the potential of neck tension (Fz) reduction in 3-year-old dummy installed forward-facing when subjected to three head static restraints (head strap, head support, cervical collar) as well as an overhead shield car seat in order to identify solutions for a device to avoid or mitigate neck injuries. To simulate frontal impacts, a 3-year-old dummy from Q series was installed on a reinforced vehicle body fixed on a sled test equipment where the United Nations R129 pulse was applied. Both head strap and head support were not able to reduce neck tension due to the high Q3 dummy’s torso displacement up to the child seat straps and were broken or released from child seat prior restraining head movement. Furthermore, parents would not be motivated to install head restraints daily because each device requires a specific adjustment for each child or journey. The overhead shield car seat was not able to reduce neck tension because the position of shield allows a large head displacement. The cervical collar offered a good resistance to the neck moment, reducing the head angular velocity and consequently reducing neck tension (Fz). This concept can be easily developed as a shoulder strap positioner requiring only a single action when installing the child and meeting United Nations R129 criteria to remove the child before buckle releasing.
Ribeiro, Rodrigo da Silva, De Arruda, Antonio Celso Fonseca
Lightweight Exosuit Combines Robotics and Functional ApparelTBMG-3526310/1/2019
Between walking and running, human gaits can cover a wide range of speeds; for example, at low speeds, the metabolic rate of walking is lower than that of running in a slow jog. The opposite also is true: at high speeds, the metabolic cost of running is lower than that of speed-walking.
Kinematic Analysis and Simulation of the Double Roller Tripod Joint2019-01-15266/5/2019
The kinematic model of the double roller tripod joint is established in order to analyze its kinematic characteristics and provide theoretical basis for its application and improvement. By means of spatial coordinate transformation, the translational and rotational motion equations of the rollers relative to the tracks and trunnions, the motion equation of the center of the tripod and the equations of the input/output angular displacement error and bending angle are derived. The motion simulation of the double roller tripod universal joint was carried out in ADAMS so as to verify the established kinematic model. The results show that the rollers of the double roller tripod joint only have periodic translational motions relative to the tracks while the rollers have both periodic translational and rotational motions relative to the trunnions. The tripod’s center does the circular motion on the tripod plane with the angular velocity 3 times of the input angular velocity. The input/output angular displacement error and bending angle have volatility, and their fluctuating frequency are 3 times of the input rotational frequency. Hence, the double roller tripod joint is a quasi-constant-velocity joint whose rollers only do pure rolling motion in the tracks.
Qiu, Yinyuan, Shangguan, Wen-Bin
Fault Feature Extraction of Elliptically Shaped Bearing Raceway2019-01-15646/5/2019
The elliptically shaped bearing (ESB) with a rigid, elliptical inner race and a flexible, thin-walled outer race is the most easily damaged core component of harmonic drive. The ESB rotates under cycle load of alternating stress due to its special elliptic structure. Hence, the fault features of ESB such as fatigue spalling and pitting are apt to be concealed by the excitation of impulses caused by alternating between major axis and minor axis. In order to diagnose the fault on raceway surfaces of ESB, a new method of CMWT-FH based on Continuous Morlet Wavelet Transform (CMWT) and FFT-based Hilbert (FH) spectrum analysis is proposed to extract the fault feature. First, the formulas of feature frequency is deduced based on the geometry and kinematics characteristics of ESB; then the CMWT method is employed to decompose the fault signal of ESB; finally, the FH spectrum analysis is performed to extract the feature frequency of faulty ESB from the decomposition signal with the maximum kurtosis in the first several layers. Compared with the traditional FH method, the feature frequency and its sideband and whether the fault location is on the outer or inner ring of faulty ESB can be identified by the proposed CMWT-FH method more accurately.
Guo, Yingying, Zhao, Xuezhi
Analysis of Rear Seat Sled Tests with the 5th Female Hybrid III: Incorrect Conclusions in Bidez et al. SAE 2005-01-17082019-01-06184/2/2019
Objective: Sled test video and data were independently analyzed to assess the validity of statements and conclusions reported in Bidez et al. SAE paper 2005-01-1708 [7]. Method: An independent review and analysis of the test data and video was conducted for 9 sled tests at 35 km/h (21.5 mph). The 5th female Hybrid III was lap-shoulder belted in the 2nd or 3rd row seat of a SUV buck. For one series, the angle was varied from 0, 15, 30, 45 and 60 deg PDOF. The second series involved shoulder belt pretensioning and other belt modifications. Results: Bidez et al. [7] claimed “The lap belts moved up and over the pelvis of the small female dummy for all impact angles tested.” We found that there was no submarining in any of the tests with the production lap-shoulder belts. Bidez et al. [7] claimed “H3-5F dummies began to roll out of their shoulder belt at… 30 degrees. Complete loss of torso support was seen at 45 degrees without significant kinetic energy dissipation.” We found that the shoulder belt remained in place and restrained the upper torso in the 0, 15 and 30 deg sled tests. At 45 and 60 deg, significant restraint was provided before the belt slipped off the shoulder. It remained in contact with the arm and chest providing restraint. Bidez et al. [7] claimed “The results indicated kinematic movement of the dummies, which were predictive of injury in all sled runs.” We found that the kinematic control was good and the biomechanical responses were well below IARVs for the 5th female Hybrid III. Bidez et al. [7] claimed “a retractor pretensioner (7 ms fire time) eliminated both submarining and torso rollout in the H3-5F in the conditions tested.” We found that the pretensioner firing pulled the lap belt up onto the abdomen inducing submarining and causing abdominal loading in two out of four tests. Conclusion: The independent review of the videos and data shows that Bidez et al. [7] misstated the results, misrepresented the findings and reached incorrect conclusions on the testing.
Viano, David, Parenteau, Chantal
Risk of Concussion in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions Evaluated Using Head Acceleration-Based Metrics2019-01-12184/2/2019
Over the past decade, there has been an increase in awareness and concern about the occurrence and long-term effects of concussions. Traumatic brain injury (TBI)-related emergency department (ED) visits associated with motor vehicle collisions, including patients with a diagnosis of concussion or mild TBI (mTBI), have increased while deaths and hospital admissions related to TBI have decreased. The diagnostic criteria for concussion have evolved and broadened, and based on current assessments and diagnostic imaging techniques, there are often no objective findings, yet a diagnosis of concussion may still be rendered. Clinical assessment of concussion may be based only on patient-reported symptoms and history, making it difficult to objectively relate the reported increase in TBI-related ED visits due to motor vehicle collisions to specific collision parameters. This study aims to perform a scientific evaluation of concussion risk during motor vehicle collisions, strengthened by objective, quantitative data, specifically focusing on head acceleration-based metrics. Data from full-scale passenger vehicle crash tests are reported for frontal and rear-end collisions with delta-Vs ranging from 6.0 to 19.0 kph (3.7 to 11.8 mph) and 5.6 to 19.5 kph (3.5 to 12.1 mph), respectively. Head linear and rotational kinematic data were recorded from instrumented Hybrid III 50th percentile male anthropomorphic test devices (ATDs) restrained in the driver’s seats. Several acceleration-based metrics currently used to assess risk of concussion were calculated and compared to published injury risk relationships that have been developed from field accident data, human subjects, and biomechanical models. Overall, the magnitudes of acceleration were low and the injury metrics corresponded to a negligible risk of concussion in these low- to moderate-speed collisions.
Pasquesi, Stephanie A., Bruno, Alexander, Courtney, Amy, Imler, Stacy M., Smedley, Janine, Prange, Michael T.
Evaluation of Occupant Loading in Low- to Moderate-Speed Frontal and Rear-End Motor Vehicle Collisions2019-01-12204/2/2019
Low- to moderate-speed motor vehicle collisions are common roadway occurrences that are generally associated with low rates of reported injury. While such complaints are generally infrequent, claims of injuries resulting from low- to moderate-speed motor vehicle collisions persist. A limited body of literature using quantitative techniques and full-scale crash tests is available to assess the injury potential associated with such collisions. Prior studies have analyzed occupant kinematics and kinetics as well as human injury risk in low- to moderate-speed collisions with older vehicle vintages but do not assess the effects of updated vehicle interior designs and occupant protection devices reflective of efforts to optimize occupant kinematics and reduce occupant loading and injury risk in more modern vehicles. This study was conducted to evaluate the injury potential for occupants of vehicles with modern design elements involved in low- to moderate-speed inline motor vehicle collisions. We expected to find that occupants in modern vehicles would demonstrate low potential for injury in such collisions. Four full-scale inline (collinear) crash tests were conducted to assess occupant loading during frontal and rear-end impacts. The vehicles used in each test were instrumented late-model, mid-sized sedans of the same make and model occupied by restrained and instrumented Hybrid III 50th-percentile male anthropomorphic test devices (ATDs). The tests involved aligned front-to-rear bumper collisions at closing speeds ranging from 7.4 kph to 33.6 kph (4.6 mph to 20.9 mph). Kinetic data collected from the instrumented ATDs were evaluated to assess the biomechanical loading environment throughout the crash pulse in both the striking (bullet) and struck (target) vehicles. Evaluation of the occupant responses established that the loads and moments generated during these low- to moderate-speed collisions were far less than accepted injury assessment reference values (IARVs). Furthermore, the recorded spinal loads demonstrated characteristics of inertial loading with similar timescales as common daily activities and, in many cases, were of magnitudes less than or comparable to loads generated by volunteers performing volitional and non-injurious activities.
Toney-Bolger, Megan, Campbell, Ian, Miller, Bruce, Davis, Mathieu, Fisher, Jacob
Occupant Kinematics and Loading in Low Speed Lateral Impacts2019-01-10274/2/2019
Instrumented human subject and anthropomorphic test device (ATD) responses to low speed lateral impacts were investigated. A series of 12 lateral collisions at various impact angles were conducted, 6 near-side and 6 far-side, with each test using an ATD and one human subject. Two restrained female subjects were utilized, with one positioned in the driver seat and one in the left rear seat. Each subject was exposed to 3 near-side and 3 far-side impacts. The restrained ATD was utilized in both the driver and left rear seats, undergoing 3 near-side and 3 far-side impacts in each position. The vehicle center of gravity (CG) change in velocity (delta-V) ranged from 5.5 to 9.4 km/h (3.4 to 5.8 mph). Video analysis was used for quantification and comparison of the human and ATD motions and interactions with interior vehicle structures. Human head, thorax, and low back accelerations were analyzed. Peak human subject head resultant accelerations ranged from 0.9 to 36.8 g’s. Peak human subject thorax and low back lateral accelerations ranged from 1.0 to 17.1 g’s and 1.3 to 12.7 g’s, respectively. The ATD was instrumented with various sensors, including a tri-axial head accelerometer and 6-axis load cells in the upper neck, lower neck, and lumbar spine. Peak ATD head resultant accelerations ranged from 3.6 to 33.5 g’s. Peak ATD upper and lower neck compression ranged from -47.4 to -991.5 N and -52.1 to -740.6 N, respectively. Peak ATD lumbar compression ranged from -72.3 to -402.1 N. Cervical and lumbar shear loading and moments are also reported.
Furbish, Christopher, Welcher, Judson, Brink, Justin, Jones, Brian, Swinford, Scott, Anderson, Robert
Reconstructing Vehicle Dynamics from On-Board Event Data2019-01-06324/2/2019
Modern vehicles record dynamic data from a number of on-board sensors for events that could precede a crash. These data can be used to reconstruct the behavior of a vehicle, although the accuracy of these reconstructions has not yet been quantified. Here, we evaluated various methods of reconstructing the vehicle kinematics of a 2017 and a 2018 Toyota Corolla based on Vehicle Control History (VCH) data from overlapping events generated by the pre-collision system (PCS), sudden braking (SB) and anti-lock brake (ABS) activation. The vehicles were driven towards a stationary target at 32-64 km/h (20-40 mph) and then after the pre-collision alarm sounded the vehicle was steered sharply right or left and braked rapidly to rest. VCH data for PCS event were recorded at 2 Hz and for the sudden braking and ABS activation events at 6.7 Hz. The steering wheel angle and the vehicle’s longitudinal acceleration, lateral acceleration, and angular rate data were extracted and used to predict the vehicle position and heading over the duration of the VCH data record preceding the vehicle coming to rest. These predictions were generated by directly integrating the VCH data and by using the VCH data as inputs to PC-Crash simulations. The predicted positions and headings were then compared to the actual position and heading data measured using differential GPS synchronized to the VCH data record. The results of these analyses provide insights into the best methods for reconstructing vehicle kinematics from VCH data and estimates of the errors associated with different reconstruction techniques.
Tsuge, Brandon, Yang, Mike, Flynn, Thomas, Xing, Peter, Lawrence, Jonathan, Heinrichs, Bradley, Siegmund, Gunter
Utilization of Psychophysiological Measurement for Determination of Human State of Mind during Brake Performance Test2019-26-03261/9/2019
This paper reviews psychophysiological measurement applied on humans, by mainly focusing on brain waves observed by EEG sensor placed on scalp during brake performance testing. During braking high physiological stress, response and fear are observed, hence brain waves are monitored during brake test. Brake performance by two drivers (i.e. Driver A & Driver B) significantly established the difference in brain potential between driver A &B. During the test, brake performance parameters such as vehicle speed, deceleration rate, brake force, stopping distance are also measured. Observed EEG signal during the braking event, revealed the difference in emotional status of two different drivers. Signal based on alpha and beta from brainwaves were evident to define the mental stability of the respective driver.
Devarajan, Pranab, Akbar Badusha, Abdul Jabbar
Switching to comfort mode18TOFHP08_088/1/2018
Switches, knobs and touch panels evolve to reduce operator fatigue. Programmability has become a central design element for engineers tasked with making work environments more comfortable for commercial-vehicle operators. Touchscreens continue to handle more functions, while switches, knobs and joysticks are all becoming more versatile as embedded electronics turn them into multi-function controls. There's a shortage of drivers in trucking and operators in off-highway, prompting a major focus on making sure that workers in both fields stay on the job. A range of control technologies play a major role in the effort to improve comfort for those who spend long hours working in cabs.
Costlow, Terry
Tip Vortex Measurements on a Cycloidal Rotor Blade at Ultralow Reynolds Numbers - Lichten Award Runner-Up PaperF-0074-2018-126805/14/2018
ABSTRACT This study provides the first in-depth analysis of the formation, strength, and convection of cycloidal rotor tip vortices. The blade force and PIV-based tip-vortex measurements were conducted for different blade aspect ratios and pitch kinematics in water at a chord Reynolds number of 18,000. Two phase-locked PIV configurations were utilized to investigate the flow field induced by the cyclorotor blade: (1) a laboratory-fixed field of view to enable investigation of vortex development at increasing vortex ages, and (2) a blade-fixed field of view to investigate the early development of the wingtip vortex at fixed 2° vortex age for varying azimuthal locations. The instantaneous blade force measurements on the cycloidal rotor showed a decrease in lift coefficient with decreasing blade aspect ratio. This is due to the higher peak swirl velocity of the tip vortex produced by the low AR blade, thereby resulting in higher induced downwash along the blade span. The aspect ratio of the blade did not affect the shape of the vortex convection trajectory, however, the rate of downward convection increased with increasing aspect ratio due to the higher thrust produced. The tip vortices showed self-similarity in both the velocity and the circulation profiles. The measurements indicate that the core-radius of the vortex experiences a logarithmic growth and the swirl velocity experiences a logarithmic decay, with vortex age due to viscous diffusion. When compared to previous helicopter rotor studies, the observed vortex dynamics from the present study exhibit increased viscous diffusion, likely due to the significantly lower Reynolds number. The tip vortex strength varied cyclically with blade azimuthal location due to the cyclic variation of blade pitch angle and the dynamic virtual camber effects. The periodic variation in tip vortex strength leads to a periodic variation in the induced flow velocity on the blade.
McElreath, James, Benedict, Moble, Tichenor, Nathan
A Truly Biomimetic Hover-Capable Flapping Wing RobotF-0074-2018-126815/14/2018
ABSTRACT This paper describes the development of a biomimetic robotic hummingbird that utilizes biologically inspired wing kinematic modulation strategies for active stability and control. By tilting the flapping planes, varying the relative wing flapping amplitude, and shifting the mean position of the flapping stroke, the robotic hummingbird is able to modulate the magnitude, direction, and location of the lift vector of each of the wings in the same way that hummingbirds do to maneuver and stabilize themselves. In addition to the control strategies, biologically inspired, flexible, aeroelastically tailored wings were developed for use on the vehicle. Flight tests were conducted in which the vehicle was flown in a controlled hover using combinations of control techniques to quantify the effectiveness of each in stabilizing the vehicle. In the present study, emphasis was placed on pitch control, where two different control strategies were investigated, which were (1) pure tilting of the stroke plane, and (2) stroke mean shifting. Based on the flight experiments, a combination of 90% mean shifting and 10% stroke tilting proved to be significantly more effective than pure stroke plane tilting with almost 40% decrease in drift and attitude oscillations. This is the first ever study where the exact kinematic control strategies used by real hummingbirds and two-winged insects are implemented on a robotic flyer and investigated through free-flight testing.
Coleman, David, Benedict, Moble
Mass and Kinematic Analysis of Compound Split with Simulation of the Shifting Process for Variable Rotor SpeedF-0074-2018-128545/14/2018
ABSTRACT The investigation presented in this paper is part of the project VARI-SPEED which aims to invent a speed variable drivetrain for different rotorcraft configurations. A kinematic and a mass analysis of compound split transmissions (CS) variations and a rotorcraft drivetrain simulation model to analyze the dynamic behavior during rotor speed change were performed. All solutions have the same power flow in the variator path but different fixed carrier transmission ratios of the planetary gears, which lead to a difference in mass. CS can be used as two speed transmissions and as continuous variable transmissions (CVT). As a two speed transmission less torque and friction energy is induced in the clutches than in a double clutch transmission, but CVT enable a smooth transition with no friction losses. CS offer the opportunity to vary rotor speed which decreases the overall power demand and lead to a more ecologically efficient rotorcraft aviation.
Amri, Hanns, Hartenthaler, Katharina, Weigand, Michael
Effect of Rotor Geometry on UAV-Scale Cycloidal Rotor Hover PerformanceF-0074-2018-126825/14/2018
ABSTRACT This paper focuses on systematic time-averaged thrust and power measurements to characterize the effect of rotor geometry on the performance of a cycloidal rotor operating at Reynolds numbers between 100,000 and 300,000. A cycloidal rotor is a revolutionary horizontal-axis propulsion device that has proven to benefit from increased maneuverability and aerodynamic efficiency at micro air vehicle (MAV) scales. The current study aims to investigate cycloidal rotor performance at significantly larger UAV-scales. Towards this, experiments were conducted for a range of rotational speeds across different blade pitch amplitudes for rotor configurations with varying airfoils, blade spans, chord-by-radius ratios, and number of blades. The study found that the optimal pitch amplitude for symmetric pitch kinematics was highly dependent on the configuration due to changes in rotor inflow and flow curvature effects. An airfoil thickness as high as 25% of chord was capable of efficiently generating thrust and thicker airfoils provide efficient operation over a wider range of pitch amplitudes. Changing the blade span showed negligible change in thrust and power per unit area and power loading. Changing the chord-by-radius ratio resulted in increases in thrust at a fixed speed and power loading up to a current optimal ratio of 0.66. Increasing number of blades resulted in a steep decrease in thrust per unit blade area. Examining all of the tested configurations allowed for an optimal solidity range to be found of between 0.30 and 0.40. Based on the 31 unique configurations tested at 6 pitch amplitudes each in the present study, at an operating Reynolds number of 200,000, the optimal cycloidal rotor configuration had a chord-by-radius ratio of 0.66, 3 blades featuring a blade aspect ratio (span/chord) of 4 and a NACA 0020 airfoil, rotor aspect ratio (span/diameter) of 1.33 and pitch amplitude of 40 deg and produced a FM of 0.6.
Kellen, Adam, Benedict, Moble
An Analytical Review and Extension of Two Decades of Research Related to PC-Crash Simulation Software2018-01-05234/3/2018
PC-Crash is a vehicular accident simulation software that is widely used by the accident reconstruction community. The goal of this article is to review the prior literature that has addressed the capabilities of PC-Crash and its accuracy and reliability for various applications (planar collisions, rollovers, and human motion). In addition, this article aims to add additional analysis of the capabilities of PC-Crash for simulating planar collisions and rollovers. Simulation analysis of five planar collisions originally reported and analyzed by Bailey [2000] are reexamined. For all five of these collisions, simulations were obtained with the actual impact speeds that exhibited excellent visual agreement with the physical evidence. These simulations demonstrate that, for each case, the PC-Crash software had the ability to generate a simulation that matched the actual impact speeds and the known physical evidence. Simulation of a full-scale rollover test reported by Asay [2010] is also examined. For this test, we obtained a simulation that exhibited an excellent visual match with the pre-roll tire marks and furrows and in which the vehicle rolled 7 times, just as it did in the actual test. The rest position of the vehicle was well matched, though a portion of the simulated roll trajectory did not match the actual roll trajectory. These areas of additional analysis extend the prior literature.
Rose, Nathan A., Carter, Neal
2021-12-29.TEST Development of a Vehicle-Based Experimental Platform for Quantifying Passenger Motion Sickness during Test Track Operations2018-01-00284/3/2018
Motion sickness in road vehicles may become an increasingly important problem as automation transforms drivers into passengers. Motion sickness could be mitigated through control of the vehicle motion dynamics, design of the interior environment, and other interventions. However, a lack of a definitive etiology of motion sickness challenges the design of automated vehicles (AVs) to address motion sickness susceptibility effectively. Few motion sickness studies have been conducted in naturalistic road-vehicle environments; instead, most research has been performed in driving simulators or on motion platforms that produce prescribed motion profiles. To address this gap, a vehicle-based experimental platform using a midsize sedan was developed to quantify motion sickness in road vehicles. A scripted, continuous drive consisting of a series of frequent 90-degree turns, braking, and lane changes were conducted on a closed track. The route was selected to be representative of naturalistic urban driving conditions and parameterized in terms of lateral and longitudinal acceleration intensities likely to produce motion sickness. Vehicle instrumentation included simultaneous measure of vehicle acceleration, passenger head kinematics, self-reported motion sickness ratings and associated sensations, and physiological responses. A no-task condition involved normative passenger behavior and unconstrained gaze. During the task condition, passengers read a handheld mini iPad tablet. The resulting vehicle-based experimental platform provided a reliable methodology designed to quantify motion sickness. Knowledge generated from studies with this platform will inform the design of AVs and the development and evaluation of countermeasures.
Jones, Monica Lynn Haumann, Sienko, Kathleen, Ebert-Hamilton, Sheila, Kinnaird, Catherine, Miller, Carl, Lin, Brian, Park, Byoung-Keon, Sullivan, John, Reed, Matthew, Sayer, James
Low-Cost Mechanical Device for Minimally Invasive SurgeryTBMG-285513/1/2018
A new type of mechanical instrument was developed to perform complex, minimally invasive procedures, also known as laparoscopic surgery. The technology could lead to less trauma for patients and shorter recovery times after surgery. The technology is based on National Science Foundation (NSF)-funded engineering research, and is being commercialized by FlexDex Surgical, a spinoff founded by University of Michigan engineers (Figure 1).
Combining Machine and Nanoparticles for Better Transplant OutcomesTBMG-2820412/28/2017
A team of experts in rehabilitation robotics used a robotic system — the Tethered Pelvic Assist Device (TPAD) — to study whether or not Parkinson’s disease affects patients’ balance and diminishes their ability to react and adapt to walking with perturbations.
Device-Free Motion Tracing Using WiFi SignalsTBMG-2797912/1/2017
Fine-grained human motion tracing — the ability to trace the trajectory of a moving human hand or leg, or even the whole body — is a general capability that is useful in a wide variety of applications. It can be used for gesture recognition and virtual touch-screens (e.g. Kinect-style natural user interfaces), activity recognition, monitoring of young infants and the elderly, or security applications such as intruder detection. Motivated by these applications, depth-sensing-based systems have been developed to implement motion tracing capabilities in cameras; however, these devices are limited because they have a constrained field of view (around 2 to 4 m range with a 60-degree aperture), and do not work in non-line-of-sight scenarios, preventing their use in many applications such as whole-home activity recognition, security, and elderly care.
Paper-Thin Device Acts as a Loudspeaker and MicrophoneTBMG-2802612/1/2017
A paper-thin, flexible device was created that can generate energy from human motion, and can act as a loudspeaker and microphone. The transducer is ultrathin, flexible, scalable, and bidirectional, meaning it can convert mechanical energy to electrical energy, and vice-versa.
Mapping Brain Activity Improves Prosthetic DesignTBMG-2803811/30/2017
Researchers have demonstrated how brain activity is used to identify different terrains — level ground and stairs, for example — a key step in developing prosthetics that allow the user’s prosthesis to automatically adjust to changing ground conditions in real time.
Ultrathin Device Harvests Electricity from Human MotionTBMG-273379/1/2017
A new, ultrathin energy harvesting system has the potential to harvest electricity from human motion. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.
Experimental and Computational Studies to Understand Unsteady Aerodynamics of Cycloidal Rotors in Hover at Ultra-low Reynolds NumbersF-0073-2017-120015/9/2017
ABSTRACT This paper provides a fundamental understanding of the unsteady aerodynamic phenomena on a cycloidal rotor blade operating at ultra-low Reynolds numbers (Re∼18,000) by utilizing a combination of experimental (force and flowfield measurements) and computational (CFD) studies. For the first time ever, the instantaneous blade fluid dynamic forces on a rotating cyclorotor blade were measured, which, along with PIV-based flowfield measurements revealed the key fluid dynamic mechanisms acting on the blade. A 2D CFD analysis of the cycloidal rotor was developed and systematically validated using both force and flowfield measurements. Studies were performed with both static and dynamic blade pitching. Direct comparison of the static and dynamic pitch experimental results helped isolate the unsteady phenomena (such as dynamic stall, unsteady virtual camber, etc.) from the steady effects. The dynamic blade force coefficients were almost double the static ones clearly indicating the role of unsteady mechanisms on force production on cyclorotor blades. For the dynamic case, the blade lift monotonically increased even up to ±45° pitch amplitude due to dynamic stall phenomenon; however, as expected, for the static case, the flow separated from the leading edge after around 15° with large laminar separation bubble (LSB) and eventually completely separating at higher pitch angles. For both static and dynamic pitching cases, there was significant asymmetry in the lift and drag coefficients between positive and negative pitch angles due to the flow curvature effects (virtual camber). CFD flow solution and PIV measured flowfield correlated well and both showed the formation and shedding of strong dynamic stall or leading edge vortices, especially at higher pitch amplitudes, which is the reason for the stall delay and force enhancement. Also, the dynamic stall process during the upper half of the trajectory was significantly different from the lower half even with symmetric blade pitch kinematics because of the reversal of dynamic virtual camber from the upper to the lower half. Even at such low Reynolds numbers the pressure forces, as opposed to viscous forces, were found to be dominant on the cyclorotor blade. The power required for rotation (rather than pitching power) was the domineering component of the total blade power for the dynamic pitching case.
Walther, Carolyn, Lakshminarayan, Vinod, Coleman, David, Benedict, Moble
Gesture-Based Controls for Robots: Overview and Implications for Use by SoldiersTBMG-268255/1/2017
Afuture vision of the use of autonomous and intelligent robots in dismounted military operations is for soldiers to interact with robots as teammates, much like soldiers interact with other soldiers. Soldiers will no longer be operators in full control of every movement, as the autonomous intelligent systems will have the capability to act without continual human input. However, soldiers will need to use the information available from, or provided by, the robot. One of the critical needs to achieve this vision is the ability of soldiers and robots to communicate with each other. One way to do that is to use human gestures to instruct and command robots.
Gesture-Based Controls for Robots: Overview and Implications for Use by Soldiers17AERP05_065/1/2017
Developing a more effective means to communicate with robotic devices. Army Research Laboratory, Aberdeen Proving Ground, Maryland A future vision of the use of autonomous and intelligent robots in dismounted military operations is for soldiers to interact with robots as teammates, much like soldiers interact with other soldiers. Soldiers will no longer be operators in full control of every movement, as the autonomous intelligent systems will have the capability to act without continual human input. However, soldiers will need to use the information available from, or provided by, the robot. One of the critical needs to achieve this vision is the ability of soldiers and robots to communicate with each other. One way to do that is to use human gestures to instruct and command robots. The use of gestures as a natural means of interacting with devices is a very broad concept that encompasses a range of body movements, including movements of the hands, arms, and legs, facial expressions, eye movements, head movements, and/or 2-dimensional (2-D) swiping gestures against flat surfaces such as touch screens. Gesture-based technology is already in place and commonly used without special instruction required for effective use. A common example of a well-designed gestural command is the use of hands to “wave” to activate devices (e.g., public bathroom faucet). This concept is also common to gaming interfaces and is now extending to other private and public domains such as automobile consoles.
Using Dempster-Shafer Fusion for Personnel Intrusion Detection17AERP04_094/1/2017
New technique enables the use of ultrasonic micro-doppler and PIR sensors for improved security. US Army RDECOM-ARDEC, Picatinny, New Jersey The Dempster-Shafer (D-S) mass function is used in effect as a common representation of heterogeneous sensor data. In order to cast each data source in this form, first the raw data is reduced to points in a multi-dimensional feature space specific to each sensor. From there, an approach is outlined that uses a distance metric in the feature space to assign mass to each state in the class hierarchy. This hierarchy begins with the full frame of discernment which represents complete uncertainty. From there it proceeds as an n-array tree broken down into further subclasses until the finest granularity of classification for the specific sensor is reached. For an input point to be classified, mass is assigned iteratively down the tree. In doing so, two key steps are taken. First, the uncertainty is estimated as a function of the ratio of the distance between the two closest child nodes. If the input point is deemed equidistant from the child nodes, there is a great deal of uncertainty and the mass function should reflect that. On the other hand, significant disparity indicates a much greater likelihood of one subclass. This distinction leads to the second step, where any mass not assigned to uncertainty is split between the child nodes as a function of the ratio of their distances.
Yaw Rate Based Trailer Hitch Angle Estimation for Trailer Backup Assist2017-01-00273/28/2017
In the current Ford Pro-Trailer Backup Assist (TBA) system, trailer hitch angle is determined utilizing the reverse camera of the vehicle. In addition to being sensitive to environmental factors such as lighting conditions and occlusion, the vision-based approach is difficult to be applied to gooseneck or fifth wheel trailers. In this paper, a yaw rate based hitch angle observer is proposed as an alternative sensing solution for TBA. Based on the kinematic model of the vehicle-trailer, an instantaneous hitch angle is first derived by utilizing vehicle yaw rate, trailer yaw rate, vehicle velocity and vehicle/trailer parameters provided by the TBA system. Due to signal errors and parameter uncertainties, this instantaneous hitch angle may be noisy, especially at lower vehicle speed. To improve the estimation accuracy, a Kalman filter (or an extended Kalman filter) which is based on the vehicle-trailer kinematic model is then formulated to obtain the optimal estimate, with the instantaneous hitch angle treated as a pseudo-measurement. Experiment results verify the accuracy and robustness of the proposed approach, and that the same algorithm can be applied to both conventional trailers and gooseneck/fifth wheel trailers.
Xu, Li, Tseng, Eric, Pilutti, Thomas, Schondorf, Steven
Characterizing Vehicle Occupant Body Dimensions and Postures Using a Statistical Body Shape Model2017-01-04973/28/2017
Reliable, accurate data on vehicle occupant characteristics could be used to personalize the occupant experience, potentially improving both satisfaction and safety. Recent improvements in 3D camera technology and increased use of cameras in vehicles offer the capability to effectively capture data on vehicle occupant characteristics, including size, shape, posture, and position. In previous work, the body dimensions of standing individuals were reliably estimated by fitting a statistical body shape model (SBSM) to data from a consumer-grade depth camera (Microsoft Kinect). In the current study, the methodology was extended to consider seated vehicle occupants. The SBSM used in this work was developed using laser scan data gathered from 147 children with stature ranging from 100 to 160 cm and BMI from 12 to 27 kg/m2 in various sitting postures. A principal component (PC) analysis was conducted based on these scans along with the manually-measured body landmarks, and 100 PC scores were retained to account for 99% of variance in the body shape and sitting postures. A PC-based fast fitting method was applied to estimate the occupant characteristics by fitting the SBSM to an incomplete depth image of a subject. The results demonstrate that a fast, inexpensive system can be used to produce useful estimates of occupant characteristics that could be applied to improve personalization of component adjustments, restraint systems, and infotainment systems.
Park, Byoung-Keon Daniel, Reed, Matthew P.
Extensional Rheology: New Dimension of Characterizing Automotive Fluids2017-01-03643/28/2017
This paper describes the basic principles of extensional rheometry, and the successful application to a variety of automotive fluids, including gear lubricants, paints, and forming lubricants. These fluids are used under very complex flow fields containing strong extensional (elongational) components. While exact derivation of extensional viscosities involves sophisticated theories, the measurement of liquid filament break-up time can provide fruitful information. Gear lubes showed different break-up time according to the kinematic viscosities. Addition of viscosity modifier (acrylic copolymer) significantly increased the breakup time, whereas surfactants had little effect. Clearcoat paint sample increased the breakup time, perhaps due to the deterioration. The waxy stamping lubricant showed remarkable change in the extensional properties as the temperature is raised. The extensional data obtained showed the promise of the technique to understand the performance of these fluids in working conditions (e.g. spraying, coating, and stamping).
Ohtani, Hiroko, Ellwood, Kevin, Pereira, Gustavo, Chinen, Thiago, Selvasekar, Siddharthan
Characterization of Janus V3 After Market Vehicle Camera with Global Positioning and 3-Axis Accelerometer2017-01-14203/28/2017
This study presents a method to characterize the accuracy and precision of video-acceleration-position (VAP) devices, and presents results from testing of one such vehicle camera (“dashcam”) with global positioning system (GPS) used by taxi companies nationwide. Tests were performed in which vehicle kinematic data were recorded in a variety of real world conditions simultaneously by the VAP device, accelerometers, and a proven GPS-based speed sensing and data acquisition system. Data from the VAP device was compared to data collected by the reference instruments to assess timing, precision, and accuracy of reported parameters. Still images from the VAP video recording were compared with three dimensional laser scan data in order to analyze field of view. Several case studies are discussed, and some guidelines and cautions are provided for use of VAP data in accident reconstruction applications.
White, Kirsten, Merala, Raymond
Automotive Vision & Obstruction Assessment For Driver2017-26-00121/10/2017
This paper makes an attempt to focus on a study to evaluate angle of vision and obstruction in a vehicle, it is an objective assessment through different percentiles of population. In a view of Safety and comfort of a driver, a good perception of environment in which his vehicle is operating will be a determining component. Driver visibility and hidden corner in vehicle is a major safety area for passengers and pedestrian. Driver eye vision is an important key factor to design vehicle windshield, rear window and A-Pillar/ B-Pillar, positioning of side view mirror and IRVM based on anthropometry data. This study focuses on method of capturing and measuring the i) Driver's Direct field of vision that the driver sees directly by moving his/her eyes ii) Driver's Indirect field of vision in which driver views indirectly by using imaging devices Rear View mirror, Display cameras. iii) Driver's Angle of obstruction - by A pillar, B pillar. This is done by using SAE manikin with vision angle device across different percentile as per SAE J941 Eye ellipse method. This gives objective values of vision angle and windshield vision area for different percentiles. This will help to establish subjective to objective correlation of vision angle and area of obstruction, which can significantly detect the issues pertaining to field of vision. The study will further support in resolving design issues of mirror, sun visor, wiper, defroster requirements.
Narayanan, S Lakshmi, Palraj, Suresh, Mani, Madanagopal, Pathak, Shekhar
Vision Factors Considerations in Rearview Mirror DesignJ985_201611 (Historical)11/7/2016
The design and location of rear-viewing mirrors or systems, and the presentation of the rear view to the driver can best be achieved if the designer and the engineer have adequate references available on the physiological functions of head and eye movements and on the perceptual capabilities of the human visual system. The following information and charts are provided for this purpose. For more complete information of the relationship of vision to forward vision, see SAE SP-279.
Driver Vision Standards Committee
Research on Transmission Efficiency of Mechanical Transmission Based on Test Bench2016-01-235610/17/2016
This paper mainly researches transmission efficiency (TE) of mechanical transmission in relation to the temperature of lubricating oil. Firstly the formula of TE is calculated about the kinematic viscosity of lubricating oil, then analyze the relationship between kinematic viscosity and temperature of lubricating oil, and finally the formula of TE which is related to the oil temperature is put forward. In order to verify the theoretical formula, the test bench for mechanical transmission is designed, which is used to research the N109 transmission of one mini car. The bench can be used to measure the curve of TE under different speed , load and lubricating oil temperature. The optimum operating temperature of the transmission is obtained by analyzing the measured data and theoretical calculation results. The test bench adopts 2 AC asynchronous motors to respectively simulate the driving and load performance of a vehicle. In this test bench, the control software of host computer is programmed by C++, the slave computer adopts PLC to control the S120 control cabinet which regulates the rotational speed of driving motor(DM) and the torque of load motor (LM).
Tian, Shaopeng, Li, Geng, Que, Tongliang
Impact of Aniline Octane Booster on Lubricating Oil2016-01-227310/17/2016
This paper describes the observed impact of aniline octane booster and more specifically N-Methyl Aniline (NMA) on lubricating oil, following field issues encountered in vehicles in certain areas of the world where aniline based octane booster was assumed to be used. The observed field issue was heavy sludge formation, leading to engine malfunctions. The impact of NMA on lubricating oil could first be replicated using a modified version of the CEC L-109 oxidation bench test, with oil diluted with fuel and NMA at start of test. Significant kinematic viscosity (KV100) increase at the end of test was evidenced, especially as NMA content was increased in the oil. Total base number (TBN) evaluated at end of test also showed values above fresh oil (at or above 4.5 wt% NMA) that was consistent with observations from the field. The assessment of NMA impact was then scaled up using ACEA black sludge engine test. Tests run with 3.5 wt% NMA added to black sludge reference fuel led to poorer sludge rating compared with standard black sludge test. Increased sludge formation in presence of aniline based octane booster evidenced on black sludge test was also consistent with observations from the field. Modified CEC L-109 oxidation bench test correlated to black sludge test in terms of sludge rating trend. However, no correlation could be found for kinematic viscosity increase and further work is in progress to understand the root cause, including impact of engine oil formulation.
Marie, Herve, Rigol, Sascha, Deeg, Hans Peter, Philipp, Harald
Vibration Assisted Drilling of Aerospace Materials2016-01-21369/27/2016
Insufficient chip extraction often leads to disruptions of automated drilling processes and will have a negative impact on the surface qualities. One opportunity to avoid chip accumulation is based on a kinematically enforced chip breakage caused by sinusoidal axial oscillations of the drilling tool. Recent investigations have shown that the quality of chip extraction is, amongst others, considerably depending on the chip shape and mass which are defined by the cutting parameters feed, amplitude and frequency. So far only mechanical systems in the form of tool holders have been available on the market, which are restricted to a fixed frequency (oscillation frequency is coupled to the spindle speed). In the present study a spindle with magnetic bearings was used which allows to adjust the oscillation frequency independent of the spindle speed and therefore enables all opportunities to affect the generated chip shapes. Based on a kinematic model of the uncut chip shape, cutting parameters have been selected specifically, in order to achieve appropriate chip extraction. It was shown, that the number of oscillations per revolution does have a major influence on the resulting chip shape and the corresponding quality of chip extraction as well as the resulting borehole quality.
Pecat, Oliver, Paulsen, Tebbe, Katthöfer, Philipp, Brinksmeier, Ekkard, Fangmann, Sascha
Navigating the Design and Production of Wearable Medical DevicesTBMG-254069/1/2016
Imagine patients with chronic conditions being monitored without having to be in a doctor’s office, or patients with more serious issues being monitored and treated outside the intensive care unit in a much less costly hospital room — or even at home. That’s the promise of wearable medical devices, a market that has been around for decades, but is being re-energized by new technology, including wireless communication.
Modified Monitor Provides Glasses-Free 3D for Pilots and GamersTBMG-252338/1/2016
When flying the increasingly crowded skies, pilots need to have an arsenal of information: altitude, airspeed, fuel level, distance to their destination, and the location of other planes in the sky. All of this information is presented in a series of two-dimensional instruments, panels, and readouts, meaning the pilot has to mentally assemble the information and translate that into the 3D world to better understand the relationship among air, ground, and traffic. NASA has long been interested in making it as easy as possible for pilots and astronauts to have the best information available to ensure safe flights, knowing that humans are imperfect creatures.
Calculation and Measurement of the Time to Complete In-Vehicle Navigation and Route Guidance TasksJ2365_201607 (Current)7/12/2016
This Recommended Practice can apply to both Original Equipment Manufacturer and Aftermarket route-guidance and navigation system functions for passenger vehicles. The methods apply only to the presentation of visual information and the use of manual control inputs to accomplish a navigation or route guidance task. They do not apply to visual monitoring tasks which do not require a manual control input, such as route following. Voice-activated controls or passenger operation of controls are also excluded.
Driver Metrics, Performance, Behaviors and States Committee
Adverse Aeroelastic Roll/Lateral Rotorcraft-Pilot Couplings AnalysisF-0072-2016-114425/17/2016
The paper investigates the basic mechanism of aeroservoelastic Pilot Assisted Oscillation phenomenon (PAO) about the roll axis due to the interaction with the pilot's arm biomechanics. The motivation stems from the observation that a rotor imbalance may occur as a consequence of rotor cyclic lead-lag modes excitation. The instability mechanism is analogous to the 'air resonance' phenomenon, in which the pilot's involuntary action plays the role of the AFCS. Using robust stability analysis, the paper demonstrates that, in particular, the introduction of a gain and a time-delay between the stick motion and the servoactuator displacements may reduce the gain and phase margins of the pilotvehicle system. The mechanism of instability proves that the pilot biodynamics is participating to the destabilization of the system by inputting energy directly into the flapping mode. This destabilizes the airframe roll motion which, in turn, causes lag motion imbalance. It is found that, depending on the value of the time delay involved in the lateral cyclic control, the body couples with rotor motion in a different way. In the presence of small or no time delays, body roll couples with the rotor through the lag degrees of freedom. The increase of the time delay to 140ms modifies this coupling: the body no longer couples with the rotor through lag but directly through flap motion.
Masarati, Pierangelo, Tod, Georges, Pavel, Marilena, Muscarello, Vincenzo, Quaranta, Giuseppe, Malburet, François
In-Situ Steering Dynamics Analysis of Skid Steering for Articulated Motor-Driven Vehicle2016-01-16464/5/2016
The traditional hydraulic steering mode in articulated motor-driven vehicle makes the vehicle structure complex. Further more, the forces between the front and rear part of the articulated vehicle could damage the articulated joint body in the process of vehicle steering. However, skid steering mode could make the vehicle steer with the different speed of each wheel, which is flexible without hydraulic steering system. The purpose of this paper is to introduce the principle of skid steering mode in articulated motor-driven vehicle. In this paper, the theory of traditional wheeled vehicle’s skid-steering mode and hydraulic steering mode of articulated vehicle are used to establish the in-situ skid-steering kinematic and dynamic model. Based on the model, the vehicle trajectory and the dynamic relationships among the body structure of the vehicle, longitudinal forces, lateral forces of each wheel are described. With these analyses, the kinematic and dynamic simulations are implemented according to the parameters of an underground mine articulated vehicle, which could provide references for the designing and studying of articulated motor-driven vehicle with skid steering mode.
Xu, Tao, Shen, Yanhua, Zhang, Wenming
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