Browse Topic: Comfort

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Development and Flight Demonstration of An Active Seat Mount System for Aircrew Whole-Body Vibration Mitigation on NRC Bell-412 HelicopterF-0080-2024-10415/7/2024
Helicopter aircrew are exposed to high levels of whole-body vibration (WBV) in fight operations, which may degrade their ride comfort and performance in the short-term, and contribute to some health issues in the long-term. This paper presents the latest development and flight test demonstration results of an active seat mount system that is designed to reduce helicopter aircrew WBV levels through active cancellation of the N/rev vibration peaks related to the helicopter main rotor speed. A prototype airworthy hardware of the active seat mount system has been developed based on previous bench-top-test designs to meet airframe integrity requirements for installation and flight testing on the Bell-412 helicopter. Extensive experimental results on human occupants using a shaker table facility and flight demonstrations on the NRC Bell-412 helicopter in representative flight conditions are presented and discussed. The active seat mount system has achieved significant reduction to the occupant WBV levels at the bottom seat cushion interface per ISO2631/MIL-STD-1472G metrics, and also showed effective mitigation to the occupant head vibrations. These investigations demonstrate that the active seat mount technology is a feasible solution for helicopter aircrew WBV mitigation.
Chen, Yong (Eric), Wickramasinghe, Viresh, Fereidooni, Amin
Minimum Energy Performance for Autonomous Control of Tiltrotor eVTOL OperationsF-0080-2024-10935/7/2024
The paper presents a novel strategy for minimum energy consumption in automatic conversion control of tiltrotor eVTOL aircraft, exemplified by the Aston Martin Volante Vision model. We introduce a tilt schedule methodology that strategically balances conversion and reconversion performance with climb, descent, and cruise phases to minimize overall energy expenditure. Our approach accounts for critical factors such as blade loading, operation handling qualities, and passenger ride comfort within a predefined conversion corridor. The optimized trajectories approximate the minimum energy pathway, essential for operational efficiency in urban air mobility. Analytical results demonstrate that our proposed conversion and reconversion phase profiles significantly reduce energy consumption, contributing to the sustainability of tiltrotor flight operations. This research not only enhances understanding of tiltrotor dynamics but also serves as a pivotal step toward achieving globally optimized energy usage, marking a significant advancement in autonomous flight technology for advanced air mobility systems.
Kang, Namuk, Whidborne, James, Lu, Linghai
Development of a Datadriven Model for Prediction of Vibrational Discomfort in HelicoptersF-0079-2023-180415/16/2023
Burkhardt, Tim, Özkurt, Süleyman, Schimpf, Fabian, Fichter, Walter
Performance Enhancement of Semi-active Continuous Skyhook Control Using Chaotic Map Particle Swarm Optimization-Based Stability Augmentation System15-16-01-00029/16/2022
Abstract Enhancing the performance of a ride-oriented algorithm to provide ride comfort and vehicle stability throughout different terrains is a challenging task. This article aims to improve the performance of the state-of-the-art continuous skyhook algorithm in coupled motion modes with an optimally tuned stability augmentation system (SAS). The tuning process is carried out using a chaotic map-initialized particle swarm optimization (C-PSO) approach with ride comfort and roll stability as a performance index. A large van model built-in CarSim is co-simulated with a C-PSO algorithm and control system designed in MATLAB. To realize the feasibility and effectiveness of the proposed system, a software-in-loop test is conducted on five complex ride terrains with different dominant vehicle body motion modes. The test results are compared against the passive system, four corner continuous skyhook control, and four corner type-1 fuzzy control. The test results confirm the effectiveness of the proposed system in providing better ride comfort, improved roll stability, good road holding, and eliminating the possibility of an untripped rollover. The results indicate a significant performance enhancement of CS-SAS against four corner continuous skyhook in ride road tests with an average root mean square (RMS) heave acceleration reduction of 28.41%. The results also exhibit distinct control effects on vehicle roll by mitigating the RMS-roll angle by an average of 61.52% for stability-based road tests.
Rajasekharan Unnithan, Anand Raj, Subramaniam, Senthilkumar
H145 New Comfort Experience: Upgrading From Four-Bladed HMR To Five-Bladed BMRF-0078-2022-175175/10/2022
ABSTRACT
Rammer, Raphael, Priems,  Martijn, Dreher, Stefan, Dieterich,  Oliver
From Helicopter Vibrations to Passenger Perceptions: A Closer Look on StandardsF-0076-2020-1643310/5/2020
The serial introduction of passive and active anti-vibration means lead primarily to the reduction of the vibration levels at blade passage frequencies Nb/rev. Consequently, other- previously unnoticed- sources of vibration are perceived by rotorcraft occupants. Therefore, a comprehensive vibration assessment metric is required to characterize the impact of different vibration sources of helicopters regarding passenger comfort. Since the advance of industrial/military aerial transport machines, several vibration assessment metrics were developed such as the Intrusion Index (ADS-27A-SP), the overall ride value av (ISO2631-1) and the NASA DISC model. However, these metrics have deficiencies regarding the evaluation of complex rotorcraft vibrations, e.g. the Intrusion Index favors only the rotor harmonics in the vibration evaluation, the overall ride value av is based on uniaxial, sinusoidal oscillations at discrete frequencies and the NASA DISC model considers only vibration measurements on the floor and not on other vibration contact surfaces. Since the rotorcraft vibrations are characterized by the presence of triaxial, multiple vibration sources it is unclear whether one of these metrics is appropriate to assess the perceived discomfort. The work presented in this paper addresses this topic. The suitability of existing vibration evaluation metrics, especially av, regarding typical rotorcraft vibration patterns is investigated. For that purpose, a systematic whole-body vibration campaign was performed, in which human subjects were seated in a helicopter seat on a motion platform and exposed to helicopter specific vibration patterns of which specific frequencies were systematically attenuated or increased. Participants rated the perceived discomfort using magnitude estimation. The campaign reveals, that the overall ride value av is not well-suited to predict and to compare the discomfort of different vibration spectra. Especially in vertical direction, the application of av will significantly overestimate the discomfort. This implies that this metric is not appropriate for evaluation of helicopter specific vibrations and could be improved. The results in this paper are a first step in that direction but more comprehensive analyses of helicopter specific vibrations and their impact on passenger comfort are necessary.
Özkurt, Süleyman, Dieterich, Oliver, Bülthoff, Heinrich, Fichter, Walter, Rath, Tobias, Priems, Martijn, A., Suzanne
The Effect of Change in Assembly Sequence on Permanent Strain of Cab Suspension Console02-13-02-00118/20/2020
Heavy commercial vehicles play an important role in creating the trade and economic balance of countries. Also, the durability and safety of heavy commercial vehicles come to the fore. Heavy commercial vehicles consist of two parts. These are the chassis area with the equipment that allows the vehicle to move and the cabin section where the driver is located. The cabin area is the most important area that ensures the highest level of driver safety. Considering that the production of trucks is increasing day by day, it is inevitable for companies to increase their R&D activities in the field of cabin and cabin suspension systems for much safer, durable, and comfortable trucks. This study aims to determine the safe torque value of the fasteners and their assembly sequence of the Cab Suspension Console, which is one of the most important connection parts in a truck and which can cause a fatal accident by breaking. In this study, the safe torque value of the fasteners of the cabin suspension console has been determined as 180 ± 15 Nm/180 ± 10 Grad for the outer fasteners and 225 ± 18 Nm/180 ± 10 Grad for the inner fasteners. In addition, two different assembly sequences are determined and permanent strains on the part are measured. At the end of the assembly test, permanent strains on the part and other factors affecting the strain are simulated. According to the results obtained, the assembly sequence with a low permanent strain value is chosen and commissioned in production.
Yildirim, Bariscan, Öztürk, Dogan
Influence of Background Spectral Distribution on Perceptions of Discomfort Glare2020-01-06374/14/2020
The advent of light-emitting diode (LED) technology for automotive lighting allows flexibility of the spectral distribution of forward headlighting systems, while meeting current requirements for “white” illumination. As vehicle headlights have become whiter (with more short-wavelength light output) over the past several decades, their potential impacts on visual discomfort for oncoming and preceding drivers have been hotly debated. It is known that a greater proportion of short-wavelength energy increases discomfort glare, and that increasing the background light level (e.g., through roadway lighting) will decrease perceptions of discomfort. More recently it has been demonstrated that the visual system exhibits enhanced short-wavelength sensitivity for perceptions of scene brightness. As a result, roads illuminated by light sources with higher correlated color temperatures (CCTs) will be judged as appearing to be brighter than those illuminated to the same light level by sources with lower CCTs. The present laboratory study was conducted to identify whether the increased scene brightness of a road illuminated with greater short-wavelength light helps to mitigate discomfort glare more than the same scene illuminated to the same light level, but with less short-wavelength light. The results indicate that the spectral distribution of the background plays little role in the degree to which it lessens discomfort glare. The implications of these results for vehicle and road lighting practices are discussed.
Nagare, Rohan M., Bullough, John D.
A Dynamic Trajectory Planning for Automatic Vehicles Based on Improved Discrete Optimization Method2020-01-01204/14/2020
The dynamic trajectory planning problem for automatic vehicles in complex traffic scenarios is investigated in this paper. A hierarchical motion planning framework is developed to complete the complex planning task. An improved dangerous potential field in the curvilinear coordinate system is constructed to describe the collision risk of automatic vehicles accurately instead of the discrete Gaussian convolution algorithm. At the same time, the driving comfort is also considered in order to generate an optimal, smooth, collision-free and feasible path in dynamics. The optimal path can be mapped into the Cartesian coordinate system simply and conveniently. Furthermore, a velocity profile considering practical vehicle dynamics is also presented to improve the safety and the comfort in driving. The effectiveness of the proposed dynamic trajectory planning is verified by numerical simulation for several typical traffic scenarios.
Zeng, Pengyun, Ling, Zheng
Leading Women in Engineering & Science: Tracy Campbell Accardi, Vice President, Surgical Robotics Research & Development, MedtronicTBMG-362903/1/2020
What led you to choose science and/or engineering as a career, particularly in the medical device industry?
Discovery Takes Pressure Off Blood MeasurementsTBMG-362643/1/2020
Researchers at Monash University are on the verge of creating a revolutionary, portable blood pressure monitoring device that can provide data continuously to patients from the comfort of their home.
Self-Moisturizing, Smart Contact LensesTBMG-361583/1/2020
Researchers have developed a new type of self-moisturizing, smart contact lenses that maintain a layer of fluid between the contact lens and the eye using a novel mechanism.
Heat-Regulating Material for Next-Generation Space BlanketTBMG-3572012/1/2019
Drawing design inspiration from the skin of squid, researchers developed an adaptive space blanket that gives users the ability to control their temperature. The drawback to current Mylar heat-regulating blankets is static. The new material has changeable properties to regulate how much heat is trapped or released.
Ride Index Structure and Development MethodologyJ2834_201910 (Current)10/9/2019
This recommended practice defines methods for the measurement of periodic, random and transient whole-body vibration. It indicates the principal factors that combine to determine the degree to which a vibration exposure will cause discomfort. Informative appendices indicate the current state of knowledge and provide guidance on the possible effects of motion and vibration on discomfort. The frequency range considered is 0.5 Hz to 80 Hz. This recommended practice also defines the principles of preferred methods of mounting transducers for determining human exposure. This recommended practice is applicable to light passenger vehicles (e.g., passenger cars and light trucks). This recommended practice is applicable to motions transmitted to the human body as a whole through the buttocks, back and feet of a seated occupant, as well as through the hands of a driver. This recommended practice offers a method for developing a ride performance index but does not specifically describe how to apply this index to assessment or comparison of specific vehicles.
Vehicle Dynamics Standards Committee
Soft, Wearable Health Monitor with Stretchable ElectronicsTBMG-351369/1/2019
A soft and conformable health monitor can broadcast electrocardiogram (ECG), heart rate, respiratory rate, and motion activity data as much as 15 meters to a portable recording device such as a smartphone or tablet computer. The electronics are mounted on a stretchable substrate and connected to gold, skinlike electrodes through printed connectors that can stretch with the medical film in which they are embedded.
Tiny Biodegradable Circuits Release Painkillers Inside the BodyTBMG-350959/1/2019
Patients fitted with an orthopedic prosthetic commonly experience a period of intense pain after surgery. In an effort to control the pain, surgeons inject painkillers into the tissue during the operation. When that wears off a day or two later, the patients are given morphine through a catheter placed near the spine. Yet catheters are not particularly comfortable, and the drugs spread throughout the body, affecting all organs.
Experimental Investigation on Gear Rattle Noise Reduction in Passenger Car2019-01-15616/5/2019
Gear rattle noise reduction inside the passenger cabin is one of the major challenges for customer comfort enhancement. Therefore, it becomes a prime target during transmission design and development. Gear rattle is generated due to meshing teeth collision of free gears, which is caused due to torsional vibration of engine transferred through clutch. Vibrations are generated due to free gears teeth impact and are transferred to shaft, bearings and transmission housing. The sound absorption and structural vibration of transmission housing was optimized by changing the geometrical features of the transmission housing that affects radiated noise. Experimental approach for gear rattle noise reduction through transmission housing modification is described in this paper. Moreover, CAE method is also incorporated with the experiments for optimization of future vehicle transmission system designs.
Khare, Devendra Kumar, Vaishya, Abhishek Lakhanlal, Pujara, Archan Sunibhai, Krishna, Radhe, Satpathy, Kingshuk, Choudhary, Ved Prakash, Pandey, Anant
Numerical Methodology of Tuning a System to Target Frequencies by Adding Mass2019-01-15966/5/2019
To ensure ride comfort, the dynamic characteristics, such as natural frequencies, of a vehicle is often tuned to a specific value by managing the magnitude and location of some masses and/or configuration of stiffeners without sacrificing the structural strength and overall fuel performance of the vehicle. We first formulate the mathematical statement of the problem in a constrained eigenvalue form. Optimal solutions are sought using various finite element techniques. A novel methodology involving genetic algorithm and Newton’s iterative method is developed to solve the constrained eigenvalue problems. Several examples, including discrete and continuous systems, are presented to demonstrate the effectiveness and accuracy of the proposed methodology. The strategy of managing the mass location and distribution to target a preferred natural frequency or frequencies is given in the conclusion.
Chen, Longhan, Gu, Randy
Assessment of Automotive Environmental Noise on Mobile Phone Hands-Free Call Quality2019-01-15976/5/2019
Environmental noises such as wind, road, powertrain, and HVAC noise are important aspects to consider when implementing a hands-free terminal for mobile phone calling from within a car. Traditionally, these environmental noises have been exclusively considered for driver comfort; however, with the introduction of the hands-free terminals (HFT) and increasing consumer demand relative to mobile phone call quality, a broader implication of high background noise levels should be considered. HFT algorithm development and implementation can and does provide a high level of background noise suppression to mitigate these concerns, but this is often done at the expense of computational power and cumulative delay during a phone call. The more advantageous solution would be to address the problem from a source and path perspective with emphasis on reduction of noise in the frequency bands which most influence call quality performance. The assessments shown throughout this paper establish a sensitivity of HFT call quality to background noise levels based on industry-standard metrics, including those defined by International Telecommunication Union (ITU) standards. These assessments were established based on a series of experiments that include characterizing vehicle to vehicle variability with a common background noise and single vehicle sensitivity to reductions in background noise. In the background noise sensitivity investigations, filtering investigations were conducted to identify the frequency ranges which drive the most significant degradation in speech intelligibility and HFT performance. The information gained provides insight regarding the requirements for mitigating background noise in the context of both customer comfort as well as HFT performance, both of which are key factors in the perception of overall vehicle quality.
Pruetz, Jeffrey, Watson, Channing, Tousignant, Todd, Govindswamy, Kiran
Fast Accurate Non-Destructive Measurement of Absorber Impedance and Absorption2019-01-15846/5/2019
Cabin acoustic comfort is a major contributor to the potential sales success of new aircraft, cars, trucks, and trains. Recent design challenges have included the increased use of composites, and the switch to electrically powered vehicles, each of which change the interior noise spectral content and level. The role of acoustic absorption in cabins is key to the optimisation of cabin acoustic comfort for modern vehicles, with acoustic impedance data needed in order to assess and optimise the impact of each component of a given lay-up. Measurements of absorbing interior trim are traditionally performed using either sample holder tests in a static impedance tube (impedance and absorption), or through tests in reverberation rooms (absorption only). Both of these procedures present challenges. In-tube absorption and impedance measurements are destructive, requiring highly accurate sample cutting and sealing. Reverberation room absorption measurements are subject to the effects of varying room diffusion, along with the impact of edge diffraction, sample geometry, and location. Finally, while non-destructive methods using hand-held probes also measure absorption, they are not able to measure impedance accurately. This paper describes fast non-destructive tests using a portable flanged impedance tube, and how they be used to quantify and optimise the absorption of interior trims. Measurements are made on non-locally reacting lay-ups, with the results corrected to equivalent in-tube results using a flanged-to-sample holder correction factor. The corrected flanged tube results are then compared with baseline in-tube measurements. Discussions address data quality and how the non-destructive measurements may be used to optimise lay-ups for increased absorption.
Murray, Paul B., Alexander, Jon, Kunio, Jason, Larsen, Flemming
Flexible, Transparent, Wearable Bio-PatchTBMG-346396/1/2019
Silicon nanoneedle patches are currently placed between skin, muscles, or tissues where they deliver exact doses of biomolecules. Commercially available silicon nanoneedle patches are usually constructed on a rigid and opaque silicon wafer. The rigidity can cause discomfort and cannot be left in the body very long.
Pocket-Sized Imaging Device Improves Accuracy Of Epidural PlacementTBMG-344135/1/2019
A team of bioengineers supported through a Small Business Innovation Research grant from the National Institute of Biomedical Imaging and Bioengineering (NIBIB) has developed a pocket-sized, ultrasound imaging device to aid doctors in accurately placing needles into the lumbar, or lower, spine. The novel ultrasound system incorporates hardware and software, including a computer-aided detection algorithm to enhance bone discernment—which typically is poor with ultrasound—to navigate the lumbar anatomy.
Influence of LED Spectral Characteristics on Glare Recovery2019-01-08454/2/2019
Headlight glare is a major concern of the driving public. In the past couple of years there have been concerns expressed about the use of light emitting diode (LED) lighting technologies and possible impacts LEDs may have on people, including circadian disruption, retinal hazards, and glare. Under typical use cases, vehicle headlight exposures are insufficient to cause circadian disruption or retinal damage, but can result in disability and discomfort glare, as well as glare recovery. In general, white LEDs used for illumination have greater short-wavelength content than halogen lamps used in many headlights, and short wavelengths have been implicated in visual discomfort from bright lights at night. Previous literature is inconsistent regarding whether the spectral (color) content of a glare source affects the amount of recovery time needed to see objects, following exposure to a bright light such as a vehicle headlight. Warm and cool white LEDs were used as glare sources in the present study. They were energized and exposed to study participants at one of two illuminances (low, high) for either 3 or 6 seconds, after which participants were asked to identify the orientation of a Landolt ring target located on a display screen behind the glare source. Identification times were unaffected by the spectral content of the LED, but were correlated with the "dosage" of light from the glare sources, defined as the product of illuminance and duration. Although cool white LEDs will tend to be judged as creating more discomfort than warm white LEDs, they do not result in longer glare recovery times under the range of conditions used in this study.
Skinner, Nicholas, Bullough, John
Effect of Different Seat Pan Angles and Feet-Floor Interactions on Human Body Response Using a Biodynamic Model2019-01-01694/2/2019
In recent years, study on the ride comfort of vehicles has attracted wide attention. The vibration caused by the road is transmitted to the human body through the tire, suspension, vehicle body, and the seat. Since the human body is in contact with the seat and the vibration is transmitted directly to the human body through the seat, the seat pan angle plays an important role on the vibration response of the human body. Previous studies have explored the effects of different backrest designs on human vibration response, but ignored the effects of different seat pan angles. Therefore, this paper will use a human biodynamic model combined with a 6-DOF seat model to study the effect of seat pan angles and feet-floor interaction on human vibration response. Three cases are proposed: Case 1 has a seat pan angle 8°, Case 2 has a seat pan angle 13°, and Case 3 has a seat pan angle 17°. In addition, the interface between the biodynamic model and vehicle floor has two ways of connection: rigid connection and soft connection.
Yu, Zhenzhong, Zhao, Qinghai, Ma, Yongzhi, Zhang, Hongxin, Yang, James
Vibration Control of an Active Seat Suspension System Integrated Pregnant Woman Body Model2019-01-01724/2/2019
Proportional-integral-derivative (PID) controller is effective, popular and cost effective for a lot of scientific and engineering applications. In this paper, PID and fuzzy-self-tuning PID (FSTPID) controllers are applied to improve the performance of an active seat suspension system to enhance the pregnant woman comfort. The equations of motion of thirteen-degrees-of-freedom (13-DOF) active seat suspension system incorporating pregnant woman body model are derived and simulated. PID gains are tuned and estimated using genetic algorithm (GA) to formulate GA PID controller. In FSTPID, fuzzy logic technique is used to tune PID controller gains by selecting appropriate fuzzy rules using Matlab/Simulink software. Both controlled active seat suspension systems are compared with a passive seat suspension. Suspension performance is evaluated under bump and random road excitations in order to verify the success of the proposed controllers. Theoretical results reveal that the proposed controllers using GA PID and FSTPID grant a significant enhancement of the pregnant woman comfort and her fetus.
Ali, Shaimaa A., Metered, H., Bassiuny, A. M, Abdel-Ghany, AM
Effect of Fabric Parameters on Phenomena of Electrostatic Charge Generation2019-01-04644/2/2019
Electrostatic charge generation in fabric is a common phenomenon. This phenomenon of charge generation & transfer of the same to human body is more in case of fabrics made of polyester yarns due to interface property of the material. The charge generation may result in attraction of dust on the fabric surface, clinginess & may also result in uncomfortable shock to the human body. This situation is attributed to various parameters such as fabric construction, yarn properties, yarn finish & various coating on the yarn. Since, polyester fabric is prime material used in seating; there have been many incidences of rubbing of seat fabric to human body, resulting in generation of static charge. This study focuses on understanding the effect of various fabric parameters on electrostatic charge generation. The study will also look into various potential solutions to reduce the charge generation with their merits and demerits.
Kumari, Sarita, Maheshwari, Pankaj
Microfluidics Device Can Detect Cancer Cells in BloodTBMG-342684/1/2019
Researchers at the University of Illinois at Chicago and Queensland University of Technology of Australia have developed a device that can isolate individual cancer cells from patient blood samples. The microfluidic device works by separating the various cell types found in blood by their size. The device may one day enable rapid, cheap liquid biopsies to help detect cancer and develop targeted treatment plans. The findings are reported in the journal Microsystems & Nanoengineering.
Researchers Develop Long-Lasting Disposable Health PatchTBMG-342674/1/2019
Researchers have created a health patch that offers unprecedented comfort and a long battery life, previously unseen in this type of device. The patch can also be manufactured at a fraction of the cost of previous generations, making it a user-friendly, disposable solution for ambulant patient monitoring.
Aircraft Personal Ventilation: A CFD Thermal Comfort Analysis2019-01-13473/19/2019
Nowadays, many different research efforts are being conducted to develop personal ventilation system for aircrafts. A numerical CFD study is presented as an example analysis, finding the relationship between the initial jet temperature and mass flow to the local thermal comfort on the head, chest and face. Typical regional airplane cabin geometry was used with two passengers seated. The passengers were modeled with numerical manikins with body and arms. The study first investigated whether the personal ventilation jet has influence on only one of the passengers or if it also affects the other. It was demonstrated that the proposed personal ventilation outlet can influence local thermal comfort with minimum influence on the adjacent passenger. The equivalent temperatures on the head, chest and face were calculated with different initial jet temperatures. It was shown that the three body parts present different dependence on the initial jet temperature due to the different distances of the personal ventilation outlet and varying cloth thermal resistances. Lower temperatures may cause higher discomfort than higher temperatures. It was determined that the respective comfort limits would be exceeded when jet inlet temperatures were below 19 oC or above 50 oC for an outlet mass flow of 0,0047 kg/s.
Stancato, Fernando
Magna unveils configurable seating concept at CES 201919AUTP02_102/1/2019
Magna provided a glimpse into its vision for the future of configurable cabin spaces with a life-size transforming seating demo at its booth during January's Consumer Electronics Show (CES). Driven by consumer research, the seating-system concept is designed to provide flexible and collaborative configurations aimed at an autonomous vehicle (AV) future. “Magna's seating innovation is driven by the belief that while the vehicle occupant experience will be very different with the introduction of mobility and autonomy, the functional basics will remain the same: passengers want convenience, flexibility and comfort,” Mike Bisson, president of Magna Seating, told Automotive Engineering ahead of CES. “This approach has essentially helped us create seats that adjust to the consumer, instead of having the consumer adjust to seats.”
Seredynski, Paul
Artificial Joint Restores Wrist-Like MovementsTBMG-337172/1/2019
For patients missing a hand, one of the biggest challenges to regaining a high level of function is the inability to rotate one's wrist (pronate and supinate). These are essential movements involved in everyday tasks such as using a door handle, a screwdriver, a knob, or simply turning over a piece of paper. For those missing their hand, these are much more awkward and uncomfortable tasks, and current prosthetic technologies offer only limited relief to this problem.
An Examination of Comfort and Sensation for Manual and Automatic Controls of the Vehicle HVAC System2019-01-50051/15/2019
The fast-changing and asymmetrical nature of the cabin environment challenges climate control systems in maintaining occupant comfort. This article examines the relationship between the control that occupants have over the heating, ventilation, and air conditioning (HVAC) system and their perceived comfort within the surrounding thermal environment. Three test cases using automatic control (20°C, 22°C, 24°C) and one in manual mode were evaluated via driving trials under normal road conditions in the United Kingdom during winter. In these trials, car cabin occupants felt more comfortable when using manual control than automatic (Fisher’s test, p = 2.2 × 10−16). Occupants felt neutral thermal sensations at head and foot level when using manual control. At chest level, occupants felt thermally neutral for both automatic and manual controls. This research highlights the need for further exploration of the interaction of the cabin occupants with their HVAC systems and the impact it has on their comfort perception.
Petre, Alexandra Galina, Brusey, James, Wilkins, Ross
Dynamic Spine Brace Characterizes Spine DeformitiesTBMG-336291/1/2019
Spine deformities, such as idiopathic scoliosis and kyphosis (also known as “hunchback”), are characterized by an abnormal curvature in the spine. The children with these spinal deformities are typically advised to wear a brace that fits around the torso and hips to correct the abnormal curve. Bracing has been shown to prevent progression of the abnormal curve and avoid surgery; however, the underlying technology for bracing has not fundamentally changed in 50 years.
Development of the Anti-Lift-Control for Motorcycle2018-32-007610/30/2018
In motorcycle market, there is demand for technology that makes it possible to drive fast safely. One such technology has already been commercialized; control that prevents front lift while enabling maximum acceleration performance. We have developed a more accurate version of this control. In order to maximize acceleration performance, it is necessary to keep front lift angle as close to zero as possible. Reducing output driving force helps to keep the front lift angle low, but if output driving force is reduced too much, it will degrade acceleration performance. Feedback control that reduces output driving force when front lift is detected is effective for optimizing this trade off, but increasing feedback gain too much to reduce front lift angle will cause output driving force to change suddenly, making for a less comfortable ride. In order to solve this problem, we introduced feedforward control that estimates the equilibrium between power and front lift and restricts output driving force. Estimates should be made by measuring the pitching angular acceleration of the actual body of the vehicle in order to correct for error. However when there is no front lift, pitching angular acceleration is always zero so an estimate cannot be made. Therefore when there is no front lift, the open loop estimated from the geometry of the vehicle shall be used as the estimate, to be switched for the closed loop estimate from the actual pitching angular acceleration when front lift is detected. Using the control method, while keeping the front lift angle close to zero, we were able to perform accurate control to meet the demand for maximum acceleration performance without reducing driving force too much.
Mase, Taiki, Suzuki, Takashi
SPECIAL REPORT: MEDINNOVATION BOSTON 2018TBMG-328199/1/2018
The medical device industry is built on innovation and invention. They are the drivers of change and evolution in this industry. But bringing these emerging technologies to market can be challenging. In June 2018, MEDInnovation Boston, jointly presented by Medical Design Briefs and MDG Boston, brought together leaders from across industry to share their insights and expertise. Below are just a few highlights and ideas from some of those experts.
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
Orthopedic Replacement Implants Market: Drivers and DevelopmentsTBMG-324568/1/2018
The global market for minor orthopedic replacement implants exceeded $1.5 billion in 2017. Analysts from The Business Research Company forecast the market value to grow at a rate of over 7 percent and to reach $2.2 billion in 2021 in their report “Minor Orthopedic Replacement Implants.”1 According to the report, the primary reason for this growth is the high incidence of arthritis and fractures. Osteoarthritis and rheumatoid arthritis are the major causes for joint replacement surgery, including minor orthopedic joints. The other cause for joint replacement surgery is failed previous joint replacement surgery. This article examines the trends that are driving this market, including a look at materials, regions, procedures, and regulatory developments that are shaping the future of orthopedic implants.
Ultrathin Endoscope Captures Neurons Firing Deep in the BrainTBMG-297497/1/2018
Researchers have developed an endoscope as thin as a human hair that can image the activity of neurons in the brains of living mice. Because it is so thin, the endoscope can reach deep into the brain, giving researchers access to areas that cannot be seen with microscopes or other types of endoscopes.
Ergonomics and Handheld Medical Devices: Five Vital Elements for Design SuccessTBMG-291086/1/2018
Dexterity, precision, control and comfort — without them, no handheld or hand intensive medical device is a success, for either the medical professional using it or for the patient relying on the outcomes. Ergonomically driven design guides a successful device development process from concept through prototype to market. There are always five fundamentals required for world-class handheld instruments or hand-intensive devices.
World's Smallest Optical Implantable Biodevice Controls Brain PatternsTBMG-291056/1/2018
Japanese researchers describe a new implantable device no bigger than the width of a coin that can be used to control brain patterns. The device, which can be read about in AIP Advances, converts infrared light into blue light to control neural activity and is both the smallest and lightest wireless optical biodevice to be reported.
Evaluation Method of Thermal Sensation and Comfort for Air Conditioning Performance Reduction2018-01-07754/3/2018
As a method of maintaining thermal sensation and comfort inside a passenger compartment, not only a conventional HVAC system but also a combination of a HVAC system and other devices such as seat heaters, a steering wheel heater, ventilation seats are increasing. This research developed a method to evaluate thermal sensation of a human body when using these various thermal control devices. This method can evaluate the heat balance of the human body by calculating the amount of heat exchange between a human body and the external environment, and it takes into consideration the influence of heat exchange by heat conduction with seats or a steering wheel. The human thermal model is made by dividing a human body into various segments, and it is the model that considers heat transport by blood flow for each segment. As a result of a heat balance of a human body, it is possible to derive the standard environmental temperature which is named the local-body standard new effective temperature (local SET*) for each part of a human body. Local thermal sensation is defined by a model equation that takes into consideration transient changes of a heat balance and an influence of heat storage by a whole body. Therefore, it is possible to evaluate thermal comfort of occupants in a vehicle cabin in transient and non-uniform situation. The authors conducted the experiment using actual vehicles and evaluated how much thermal sensation changes when an air conditioning system is different, using this evaluation method. Energy measurements for maintaining vehicle cabin environment and thermal sensation in the vehicle cabin were simultaneously carried out and the results of thermal sensation evaluation were shown.
ITO, Yusuke, Sakoi, Tomonori, Miyamoto, Takeshi
Automotive Thermal Environment Model to Design Climate Control Logics Based on Thermal Sensation2018-01-00644/3/2018
This paper describes newly developed model-in-the-loop simulation (MILS) which makes design for cooperative climate control logics between automotive HVAC (heating, ventilation and air conditioner) and auxiliary thermal devices more efficient in considering thermal sensation and comfort of occupants. The auxiliary thermal devices such as an air-conditioned seat and a heated steering wheel consume less energy than the HVAC, and they have a potential to improve the total energy consumption satisfying thermal comfort of occupants. However, it is not easy to design the cooperative climate control logics for these thermal devices since thermal sensation and comfort must be taken into account while the logic optimization. The proposed MILS consists of thermal-environment model, thermal-device model, ambient conditions and climate control logics. The thermal-environment model simulates dynamics of temperature distribution in a cabin and human body. Compartment model is adopted for the thermal environment model, and it provides higher-speed simulations than distributed parameter model. Thermal sensation and comfort of occupants are computed on the basis of heat loss of occupants. Local thermal sensation of occupants are estimated by equivalent temperature (Teq), and we confirmed that Teq had a linear correlation to declared values of subjects. UC Berkeley’s comfort model is used to convert local sensation to overall sensation and comfort. An HVAC, an air-conditioned seat and a heated steering wheel are modeled with experimental results, and the thermal-device models are controlled by the climate control logics. Model validation has been conducted by comparison with the experimental results. In consequence, the results of temperature and thermal sensation in simulation correspond with the experiments. Therefore we can study the effectiveness of prototyped cooperative climate control logics referring to thermal comfort and energy consumption by using the outputs of this MILS before actual vehicle tests.
Kubota, Takuya, Ishikawa, Takayuki, Tosaka, Jun, Okayasu, Hidetoshi
Evaluation of Thermal Environment in Vehicles for Occupant Comfort Using Equivalent Temperature of Thermal Manikin during Start-Stop Function with Energy Storage Evaporators2018-01-00594/3/2018
In recent years, start-stop systems have been implemented by many OEMs for improvement of fuel economy. When the engine stops, the occupant comfort typically deteriorates. Hence, the climate and fuel economy engineers are struggling to combine the passenger comfort and fuel economy. Especially in a vehicle cabin where the thermal environment becomes unsteady and highly non-uniform due to a start-stop. It is difficult to adapt any comfort evaluation index that have already been well established for a stationary/uniform space in building type environment in comparison to a vehicle cabin interior. The existing standard of ISO-14505-2 does not consider this for vehicle cabin interior condition. Hence, the authors have developed the occupant’s comfort prediction method under highly non-uniform condition and unsteady conditions and have established a new methodology [1].
Morishita, Masahiro, Uchida, Toshiya, Mathur, Gursaran D., Kato, Takenao, Matsunaga, Kazuhiko
Ride Comfort Enhancement Using Active Stabilizer2018-01-05634/3/2018
Ongoing research on active stabilizers involves not only control of the roll angle of the vehicle based on steering input but also improving ride comfort by reducing roll vibration caused by the antiphase road surface input. In that context, roll skyhook control, which applies skyhook theory to provide feedback on the vehicle roll and drive the actuators, has already been presented. Although vibration in all frequency bands can be reduced if there is no control delay, time lags or phase delays in control elements such as the communication, computation, low-pass filter, or actuators can amplify vibration. Consequently, a sufficient effect of controlling cannot be obtained. This paper will address wheelbase filtering, which produces a frequency that minimizes roll oscillation, and is used to suppress the influence of the undesirable vibration. Control signal filters considering roll-lateral coupled motions were designed, and an experiment with an actual vehicle was conducted to confirm the performance benefits.
Fujii, Daigo, Yabumoto, Hirokazu, Koumura, Shingo
Multi-Objective Optimization to Improve SUV Ride Performances Using MSC.ADAMS and Mode Frontier2018-01-05754/3/2018
Ride is an important attribute which must be accounted in the passenger segment vehicles. Excessive H point acceleration, Steering wheel acceleration, Pitch acceleration can reduce the comfort of the driver and the passengers during high frequency and low frequency rough road events. Excessive Understeer gradient, roll gradient, roll acceleration and Sprung mass lift could affect the Vehicle driver interaction during Steady state cornering, Braking and Step steer events. The concept architecture of the vehicle plays an important role in how comfort the vehicle will be. This paper discusses how to improve SUV ride performances by keeping handling performance attributes same or better than base vehicle. Multi Objective Optimization was carried out by keeping spring, bushing and damper characteristic as the design variables to avoid new system or component development time and cost. The first step in this process is DOE (Design of Experiments method) which allows to select critical or highly influence input variables and to understand the effect of input variables on output performances. The consequent Optimization leads to select the optimum from various conflicting solutions.
Lenka, Visweswara Rao, Anthonysamy, Baskar, Londhe, Abhijit, Hatekar, Harshad
Optimization of Center Console Duct Using Robust Assessment Methodology2018-01-00724/3/2018
The thermal comfort for the passenger inside the cabin is maintained by the HVAC system. To ensure a comfort for the 2nd row passengers in the cabin, it is very essential to design an efficient HVAC and rear console duct system which can deliver sufficient airflow with less pressure drop. The primary focus of the study is to assess existing airflow of the center console duct using CFD and propose improvement in its duct shape to meet the passenger comfort sitting in the rear seat. In this study, the vehicle cabin model, HVAC system and duct design was modeled using the design software UG. To analyze and estimate the behavior of the air flow of the system, a steady state simulation was performed using STAR CCM CFD software. The performance of the console duct system is judged by parameters like distribution of airflow, velocity at console duct outlet, pressure drop through the duct and the uniformity of the air flow at the passenger locations. Robust assessment methodology is followed for optimization of console duct to reduce the simulation iterations and arrive at the combination of appropriate design factors which influences the airflow, pressure drop within the duct and velocity at second row passenger locations within the short span of time. The impacts of each design factors on the output results have been analyzed extensively and best combination of design factors have been found out quickly through this methodology. Robust assessment methodology significantly aids in reducing the CFD simulation iterations by 40% and much faster than conventional optimization process. Vehicle testing was carried out for the existing and optimized console duct design to measure the improvement in airflow and velocity at passenger locations. There is a good correlation agreement between simulation and test results for the optimized design within the error of 10%. This methodology is very useful in reducing the number of prototypes, minimize the testing cost and reduce the simulation iterations during design and development stages of the program.
Vasanth, B., Khan, Mohsin, S, Sathish Kumar, Garikipati, Nagababu, NARAYANA, Sathya, Govindarajalu, Murali
CAE Methodology for Seat Assessment with H-Point Machine2018-01-13224/3/2018
Seat assessment is an important necessity for the growing auto industry. The design of seats is driven by customer’s demand of comfort and aesthetics of the vehicle interiors. Some of the few seat assessments are H-point prediction with H-point Machine (HPM); backset prediction with Head Restraint Measuring Device (HRMD); seat hardness and softness. Traditional seat development was through developing series of prototypes to meet requirements which involved higher costs and more time. The seat requirement of H-Point measurement is of focus in this paper. Though there are other commercial available software/methods to perform the H-point measurement simulations, the aim here was to assess the capabilities of an alternate Computer Aided Engineering (CAE) methodology using CAE tools - PRIMER and LS-Dyna. The pre-processing tools - Hypermesh and ANSA have been used for modeling and Hyperview tool used for reviewing the simulations. The CAE results show good correlation to test results and compare well to other commercial software/methods. This methodology has been beneficial in developing seat designs in the early development cycle much before the final prototype testing.
Manjunath, Vinay, Tuniki, Raju, Kamalakkannan, Sarath Babu, Mathur, Mohit, Kolich, Michael
Evaluating a Vehicle Climate Control System with a Passive Sensor Manikin coupled with a Thermal Comfort Model2018-01-00654/3/2018
In a previous study, a passive sensor (HVAC) manikin coupled with a human thermal model was used to predict the thermal comfort of human test participants. The manikin was positioned among the test participants while they were collectively exposed to a mild transient heat up within a thermally asymmetric chamber. Ambient conditions were measured using the HVAC manikin’s distributed sensor system, which measures air velocity, air temperature, radiant heat flux, and relative humidity. These measurements were supplied as input to a human thermal model to predict thermophysiological response and subsequently thermal sensation and comfort. The model predictions were shown to accurately reproduce the group trends and the “time to comfort” at which a transition occurred from a state of thermal discomfort to comfort. In the current study, the effectiveness of using a coupled HVAC manikin-model system to evaluate a vehicle climate control system was investigated. The test protocol prescribed a transient heat up after a cold soak of a vehicle that had been placed in a - 10 °C climate chamber. Multiple repetitions of the same scenario were run with different human subjects to reduce the influence of individual bias on the overall results and to assess the variability of test responses. The thermal sensation and comfort of the human subjects were compiled and reported in terms of average and standard deviation, which were compared to the predictions of the manikin-model system. The agreement between the manikin-model system and the human subject test results was assessed quantitatively by calculating the RMSD (root-mean-square deviation) and bias (the average error) between the predictions and the measurements.
Hepokoski, Mark, Curran, Allen, Viola, Timothy, Lindedal, Niklas, Hansson, Ronnie, Gullman, Sam
Range Extension Opportunities While Heating a Battery Electric Vehicle2018-01-00664/3/2018
The Kia Soul battery electric vehicle (BEV) is available with either a positive temperature coefficient (PTC) heater or an R134a heat pump (HP) with PTC heater combination [1]. The HP uses both ambient air and waste heat from the motor, inverter, and on-board-charger (OBC) for its heat source. Hanon Systems, Hyundai America Technical Center, Inc. (HATCI) and the National Renewable Energy Laboratory jointly, with financial support from the U.S. Department of Energy, developed and proved-out technologies that extend the driving range of a Kia Soul BEV while maintaining thermal comfort in cold climates. Improved system configuration concepts that use thermal storage and waste heat more effectively were developed and evaluated. Range extensions of 5%-22% at ambient temperatures ranging from 5 °C to −18 °C were demonstrated. This paper reviews the three-year effort, including test data of the baseline and modified vehicles, resulting range extension, and recommendations for future actions.
Meyer, John J., Lustbader, Jason, Agathocleous, Nicos, Vespa, Antonio, Rugh, John, Titov, Gene
Rubber Suspension Bushing Model Identified by General Design Parameters for Initial Design Phase2018-01-06934/3/2018
This article proposes a rubber suspension bushing model considering amplitude dependence as a useful tool at the initial design phase. The purpose of this study is not to express physical phenomena accurately and in detail and to explore the truth academically, but to provide a useful design method for initial design phase. Experiments were carried out to verify several dynamic characteristics of rubber bushings under vibration up to a frequency of 100 Hz, which is an important frequency range when designing ride comfort performance. When dynamic characteristic theory and the geometrical properties of the force-displacement characteristic curve were considered using these dynamic characteristics as assumptions, an equation was derived that is capable of calculating the dynamic stiffness under an arbitrary amplitude by identifying only two general design parameters (dynamic stiffness and loss factor) under a reference amplitude. The rubber suspension bushing model was then constructed by transforming this equation. Two verifications were carried out to confirm that the model is capable of reproducing measured bushing characteristics. Previous models consist of a large amplitude stiffness component and an artificially created friction component, and must be identified using three unknown values. In contrast, the proposed model only consists of a function derived theoretically from the above assumptions. Consequently, this model can be identified using the two unknown values described above, which are general design parameters used by suspension engineers in everyday design work.
Horiuchi, Kentaro, Sakaguchi, Shinichi
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