Browse Topic: Center of gravity (CG)

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Flight Test Evaluation of Center of Gravity Effects on a Coaxial Ultralight HelicopterF-0082-2026-02165/5/2026
This paper presents results of flight tests conducted on a coaxial ultralight helicopter. An automated flight test evaluation method is presented and exemplified through its application to steady horizontal flight. The results shown include pilot controls, helicopter attitude angles, power, thrust and torque distribution between the rotors, rotor harmonic thrust components, and teeter angles, along with their rotor harmonic components across varying flight speeds. This study focuses on the dependencies of these parameters on center of gravity position and sideslip angle.
Mindt, Maximilian, Gradkowski, Piotr, Matthia, Jonas, Mahlstedt, Dominik
Mitigation of Whirl-Flutter throughWind Tunnel Testing of a Hingeless-Hub Tiltrotor ModelSM-2026-VLADA-51931/27/2026
A 4.75-ft diameter hingeless hub proprotor model was wind tunnel tested up to the very high speeds of 205 knots, loosely corresponding to 480 knots full-scale, with parametric variations in blades, wing spar, and pylon center of gravity. Testing revealed that a gimballed-hub configuration that reached whirl flutter at 160 knots was completely stabilized when converted to a hingeless hub – using identical blades, span, and pylon. While the gimballed-hub model encountered whirl flutter at 160 knots, the hingeless-hub configuration remained stable throughout the entire test envelope up to 205 knots. The key conclusions are that a hingeless hub can eliminate whirl flutter, and that the most stable configuration is a swept-tip blade hingeless-hub rotor with the pylon center of gravity aft of the wing spar.
O'Brien, Nathan, Datta, Anubhav
Advance techniques to optimize Variable Gear Ratio steering for high Centre of Gravity vehicles.2026-26-00861/16/2026
High center of gravity (CG) and moderate Wheel track vehicles such compact SUVs has comparatively low static stability factor (SSF). Making them unstable and highly susceptible for rollover. On the top of that, to enhance the ease of maneuverability in densely populated areas, it is required to have a minimal turning circle diameter (TCD). To do so, variable gear ratio (VGR) steering stands superior to conventional constant gear ratio (CGR) steering, benefiting in both improved roll stability and agility to manoeuvre in compact spaces. To fine-tune VGR steering for specific vehicle requirements, Driver-in-the-Loop (DIL) simulation is used. This method allows for precise adjustments based on real-world driving conditions, ensuring the VGR steering C-factor curve is optimized for ideal vehicle handling performance in on-center, off-center, and transition regions of the steering wheel angle (SWA). Metrics such as SWA gradient at different lateral accelerations and C-factor transitions for
Rewale, Pratik, Kopiec, Jakub, Kumar, Deva, Rasal, Shraddhesh, Hussain, Inzamam, Nehal, S B
Driver-in-the-Loop Optimization of Tire-Vehicle Dynamics using Virtual Tire Development approach through CD Tire Models2026-26-00991/16/2026
This study provides a virtual development process using VI-Grade Driving Simulator and Adams simulation integrating CD tire models to modify all-terrain tire performance for an altered and new proposed version of an existing production vehicle. The proposed alteration introduces ride height changes, weight distribution changes, and centre of gravity changes from existing vehicle design. The proposed new vehicle variant also introduces tire change from highway terrain type to all-terrain type as it was intended to deliver some off-roading capabilities, thereby vehicle dynamics and kinematics recalibration & tuning required. The conventional development cycles through physical prototypes are time-consuming and expensive. Alternatively, this solution combines high-fidelity tire simulation, driver-in-the-loop (DIL) simulation, and multi-body dynamics analysis to reduce development time and prototype cycles. The proposed method begins with baseline correlation, augmenting Adams vehicle
Shrivastava, Apoorv, Asthana, Shivam
Design of the BIW structure for battery pack protection in case of side pole impact.2026-26-00251/16/2026
Electric vehicles (EVs) are becoming more popular than Internal Combustion Engine (ICE) powered vehicles, but their battery and motor components elevate their Gross Vehicle Weight (GVW), posing unique collision risks. Manufacturers strategically mount the high voltage (HV) battery packs under the passenger compartment to lower the Centre of Gravity and shield them from the front impacts. However, side impacts remain a concern, as the battery deformation in such instances could trigger fires or explosions, endangering occupants. To address this, crashworthiness designs adhere to New Car Assessment Program (NCAP) standards, particularly against side pole impact and side mobile barrier impact. Unlike the frontal section of BIW, which typically has larger crush space to absorb the crash energy, extensive design attention is required to the vehicle's side structure to absorb pole impacts without transmitting excessive force to the battery pack. Utilizing aluminium extrusions and sheet
Nivesh, Dharun, NAMANI, Prasad, Ramaraj, Rajasekar
Evaluation of Methods used to Determine Vehicle Center of Gravity Height2026-26-05131/16/2026
This paper contains a study of the measurement accuracies of two methods commonly used by vehicle industries and other stakeholders to determine vehicle center of gravity (CG) height. The two methods, which both appear in international standards, are the Axle Lift method and the Stable Pendulum method. The Stable Pendulum method requires a dedicated swinging platform mechanism, but it is generally considered to be more accurate than the Axle Lift method. Both methods rely on equations for computing CG height that are based on static balance models of a vehicle tested at various pitch angles. For each method, the accuracy of the resulting CG height computations is a function of the individual measurements needed in the model equations. The individual measurements needed depend on the method used, but they include weights, angles, and distance measurements. A theoretical error analysis study is presented that provides insight into the accuracy of both methods given the uncertainty in the
Heydinger, Gary, Zagorski, Scott, Bartholomew, Meredith, Andreatta, Dale
Static Rollover Stability Analysis of Heavy Tipper vehicle2026-26-00901/16/2026
Heavy tipper vehicles are primarily utilized for transporting ores and construction materials. These vehicles often operate in challenging locations, such as mining sites, riverbeds, and stone quarries, where the roads are unpaved and characterized by highly uneven elevations in both the longitudinal and lateral directions of vehicle travel. During the unloading process, the tipper bodies are raised to significant heights, which increases the vehicle's centre of gravity, particularly if the payload material does not discharge quickly. Such conditions can lead to tipper rollover accidents, causing severe damage to life and substantial vehicle breakdowns. To analyse this issue, a study is conducted on the vehicle design parameters affecting the rollover stability of a 35-ton GVW tipper using multi-body simulations in ADAMS software. The tilt table test was simulated to determine the table angle at which wheel lift occurs. Initially, simulations are performed with the rigid body model
Vichare, Chaitanya Ashok, Patil, Sudhir, Gupta, Amit
Guidelines for Repair Process Evaluation of Fiber Reinforced Composite Bonded StructureAIR6292 (Current)11/26/2025
The SAE Aerospace Information Report (AIR) is intended to be used as a process verification guide for evaluating implementation of key factors in bonded repair of fiber reinforced composite structure in a repair shop environment. The guide will be used in conjunction with a regulatory approved and substantiated repair, and is intended to promote consistency and reliability.
AMS CACRC Commercial Aircraft Composite Repair Committee
Guidelines for Repair Process Evaluation of Aluminum Bonded StructureAIR6291A (Current)11/26/2025
This SAE Aerospace Information Report (AIR) is intended to be used as a process verification guide for evaluating implementation of key factors in repair of metal bond parts or assemblies in a repair shop environment. This guide is to be used in conjunction with a regulatory approved and substantiated repair, and is intended to promote consistency and reliability.
AMS CACRC Commercial Aircraft Composite Repair Committee
Arresting Hook Installation, Land-Based AircraftARP1538C (Current)11/11/2025
This SAE Aerospace Recommended Practice (ARP) covers the recommended criteria and performance requirements for the design and installation of land-based aircraft emergency and operational arresting hooks for use on runway arresting systems. Design criteria for fully operational hooks and for carrier-based aircraft hook installations are contained in specification MIL-A-18717.
A-5B Gears, Struts and Couplings CommitteeNEW
Study on Motorcycle Rider Model Using Reinforcement Learning - Learning Examples Including Following Target Velocity and Basic Research on Rider Proficiency2024-32-00284/18/2025
In this study, an initial approach using deep reinforcement learning to replicate the complex behaviors of motorcycle riders was presented. Three learning examples were demonstrated: following a target velocity, maintaining stability at low speeds, and following a target trajectory. These examples serve as a starting point for further research. Additionally, the proficiency of the constructed models was examined using rider proficiency evaluation methods developed in previous studies. Initial results indicated that the models have the potential to mimic real rider behaviors; however, challenges such as differences between the model’s output and what humans can produce were also identified for future work.
Mitsuhashi, Yasuhiro, Momiyama, Yoshitaka, Yabe, Noboru
Necessity of Body Torsional Rigidity of Personal Mobility Vehicles (PMVs) with an Inward Tilting Mechanism2024-32-00134/18/2025
In traditional four-wheeled automobiles, the imbalance between the roll moment, which is the product of the centrifugal force during a turn acting on the center of gravity and the height of the center of gravity, and roll stiffness, which is the product of the left-right difference in tire vertical load and the tread width and commonly used among automotive suspension engineers, of the front and rear sections necessitates body torsional rigidity. However, there is a lack of specific cases and guidelines for constructing the body structure of three-wheeled PMVs (Personal Mobility Vehicles) with a tilting mechanism from the perspective of vehicle dynamics characteristics. In this paper, the basic considerations related to the dynamics of such three-wheeled PMVs are investigated. We use the term “torsional rigidity” to refer to the stiffness as the torsional deformation of the body itself, and the term “roll stiffness” to refer to the moment that counteracts the roll moment during a turn
Haraguchi, Tetsunori, Kaneko, Tetsuya
Gross Weight, CG Position, and Rotor Flapping Prediction for a Compound Helicopter using Machine LearningF-0080-2024-13285/7/2024
This study investigates the use of machine learning (ML) models to estimate the gross weight (GW), the longitudinal position of the center of gravity (CGx), and 1/rev cyclic flapping angles (Δ1c and Δ1s) of a compound helicopter with three redundant controls - main rotor RPM, collective propeller thrust, and stabilator angle. Neural Network (NN), Gaussian Process for Regression (GPR), and Support Vector Machine (SVM) algorithms are employed to develop estimation models using supervised training. The airspeed, redundant controls, main rotor controls, aircraft attitudes, and main rotor torque are selected as input variables (predictors) to the models due to their accessibility through the aircraft Health and Usage Monitoring System (HUMS). The dataset is split into low-speed and high-speed regimes to compare the prediction accuracy and training cost of separate regime models against a combined full-regime model. Separate airspeed regime GPR models showed superior performance in GW
Halder, Anubhav, Makkar, Gaurav, Gandhi, Farhan
A novel approach for Combi Braking System design considering tire's nonlinear behavior2024-26-00581/16/2024
The standard usage of Combined Braking System (CBS) in lower cc/power 2-wheeler vehicles serves to reduce stopping distance and improve braking stability. The CBS system achieves this by engaging both the front and rear wheel brakes, taking advantage of the high load transfer characteristic during 2-wheeler braking. However, the current design of the CBS system relies on linear system analysis, based on vehicle geometry, load distribution, and tire-road friction. This approach overlooks the non-linearities inherent in braking dynamics, such as tire behavior and dynamic Center of Gravity (CoG) location. Consequently, the current CBS design methodology exhibits limitations, particularly in extreme scenarios where wheel lock-up may occur, such as on low friction surfaces or during panic braking. This paper proposes the incorporation of tire non-linearities into the design of CBS systems using Pacejka's tire model. Initially, calculations are performed to optimize the braking
Khandekar, Piyush, Badiger, Kartik, Gautam, Ashish, Soni, Lokesh
Impact of Toe and Thrust Angle Misalignment on Roll Behaviour of a Heavy Commercial Road Vehicle2024-26-00561/16/2024
Heavy Commercial Road Vehicles (HCRVs) may be more susceptible to rollover incidents due to their higher centre of gravity position than passenger vehicles, and rollover is one of the significant causes of HCRV accidents. Therefore, variation in vehicle roll behaviour becomes crucial to the safety of an HCRV. Toe misalignment is a commonly observed phenomenon in HCRVs, and studying its impact on roll behaviour is important. In this work, the impact of the symmetric toe and thrust misalignment on the roll behaviour of an HCRV is analysed using IPG TruckMaker®, a vehicle dynamics simulation software. A ramp steer manoeuvre was used for the simulations, and the toe misalignment on a wheel was chosen from the range [−0.21°, 0.21°]. Variation in roll behaviour was quantified using the steering wheel angle at which one-wheel lift-off (OWL) occurred (SWA_L). Additionally, an analytical model was formulated to predict OWL and the model predictions were compared with the results from IPG
Chandran, Amarchand, Grandhe, Roshan, Mukhopadhyay, Arko, Sharma, Mitanshu, Shankar Ram, C S
SUV Multi-Link Rigid Axle Control Links Optimization for Ride and Handling Improvement2024-26-00481/16/2024
In automotive world, role of suspension system is to absorb vibrations from the road, and to provide stability while vehicle is going over bumps or uneven roads, cornering, acceleration and braking etc. For body on frame SUVs which are typically characterized by high center of gravity, it is quite critical to find best balance in ensuring stability of the vehicle and having comfortable ride performance. Rigid axle rear suspension is quite typical choice in such vehicles, wherein lower and upper control links are two important components subjected to lateral, longitudinal, and vertical loads. These links allow the vehicle to move smoothly throughout the entire range of suspension travel. Kinematics and compliance optimization of these links is major factor in definition of ride-handling performance of the vehicle. The present study describes key challenges and methodology to define position as well as orientation of control links, where-in multiple inter-related handling and comfort
Hussain, Inzamam, Jani, Harshil, Rasal, Shraddhesh, Asthana, Shivam, ahire, Manoj, Jadhav, Prashant, Lenka, Visweswara, Vellandi, Vikraman
Simulation methodology development for vibration test of Bus Body Structure code AIS 153:20182024-26-02491/16/2024
A bus is integral part of public transportation in both rural and urban areas. It is also used for scheduled transport, tourism, and school transport. Buses are common mode of transport all over the world. The growth in economy, the electrification of public transport, demand in shared transport, etc., is leading to a surge in the demand for buses and accelerating the overall growth of the bus industry. With increased number of buses, the issue of safety of passengers and the crew assumes special importance. The comfort of driver and passenger in the vehicle involves the vibration performance and therefore, the structural integrity of buses is critically important. The bus safety act depicts the safety and comfort of bus operations, management of safety risks, continuous improvement in bus safety management, and public confidence in the safety of bus transport, appropriate stakeholder involvement and the existence of a safety culture among bus service providers. In order to provide
Bijwe, Vilas B., Mahajan, Rahul, Vaidya, Rohit, Patel, Kaustubh, Hiwale, Diwakar, Walke, Abhijit Ashok
Assisted Steering Control for Distributed Drive Electric Vehicles Based on Combination of Driving and Braking2023-01-701210/30/2023
This paper presents a low-speed assisted steering control approach for distributed drive electric vehicles. When the vehicle is driven at low speed, the braking of the inner-rear wheel is combined with differential drive to reduce the turning radius. A hierarchical control structure has been designed to achieve comprehensive control. The upper-level controller tracks the expected yaw rate and vehicle side-slip angle through a Linear Quadratic Regulator (LQR) algorithm. The desired yaw rate and vehicle side-slip angle are obtained according to the reference vehicle model, which can be regulated by the driver through the accelerator pedal. The lower-level controller uses a quadratic programming algorithm to distribute the yaw moment and driving moment to each wheel, aiming to minimize tire load rate variance. Simulation and real vehicle tests compare three steering modes: front-wheel steering only, front-wheel steering + differential drive assisted steering, and front-wheel steering
Wu, Dongmei, Wang, Cheng, Du, Changqing, Zhang, Yichao
Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-00039/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
682 Guidance for Air Transport Service Bulletins (TEST POPST CT and APPSEARCH)ARINC682 (Current)9/21/2022
This document provides industry guidance to supplement ATA standards and airframe requirements, addressing gaps and vague areas to move suppliers/vendors and airframers toward a common standard for format and wording in Vendor Service Bulletins (VSB) for Air Transport components. This document supplements the VSB guidance of iSpec 2200, providing clarity of requirements and resulting in a common standard wording and format of VSBs from all suppliers on all aircraft types. The guidance in this document is intended to be applied to VSBs created and released subsequent to the release of the guidance document and will not require the retroactive update of VSBs released prior to the creation and release of the guidance.
Investigation and Analysis of Brake Factor variation and its relation with Brake Pulling.2022-01-11719/19/2022
Vehicles pull during braking can be defined as the deviation of vehicle travel from intended path of the vehicle by a margin of half a wheel track or more. It is a dynamic phenomenon with very complex inter-dependencies among the combined functioning of various aggregates such as steering system, suspension system, axles, brakes. The problem is aggravated with shorter wheelbase & higher CG (Centre of Gravity) height, where the instantaneous load transfers are sudden and of relatively high magnitude which can lead to a combination of forces that are responsible for vehicle drifting or pulling to anyone side of center-line travel. Vehicle with shorter wheelbases, high GVW and high CG heights are more prone to this unstable behavior due to sudden change in dynamic forces acting on the tires while turning and braking. Although these vehicles have some disadvantages, they are required for important applications such as stage and intercity operations and hence cannot be stopped producing due
Pandey, Prashant, Pujari, Sachin, Nagrikar, Ravi
Effect of anti-dive suspension geometry on braking stability2022-01-11729/19/2022
Suspension plays a crucial role in stabilizing, comfort, and performance of a vehicle. During vehicle braking operation, load transfer happens from rear axle to front axle resulting in shifting of vehicle’s center of gravity towards vehicle front for a momentarily duration, this phenomenon is called diving. This leads to dropping of traction at rear wheel end, resulting in lifting of rear axle with front wheel as pivot causing increase in front to rear weight ratio of vehicle system and moreover, compromising driver safety due to skidding and locking of rear. To minimize this phenomenon’s affect, optimum anti-dive suspension geometry is used to have better rear wheel end traction resulting in improved braking stability. This paper provides methodology for establishing coherence between braking and suspension geometry by providing mathematical model with various suspension geometry and its reaction force on vehicle under braking condition for predicting traction lose at rear wheel end
Patel, Sahil, Pujari, Sachin, Nagrikar, Ravi, Umbare, Deepak
Creating an Instantaneous Center of Rotation Map to Determine the Influence of Yaw Rate on Occupant Kinematics and Injury Potential in Eccentric Planar Collisions2022-01-09933/29/2022
The reconstruction of planar vehicle-to-vehicle collisions often requires a kinematic analysis of post-impact occupant motion to assist with biomechanical injury assessment. When one vehicle imparts an eccentric force on the adverse vehicle, the resulting vehicle kinematics include both translation and rotation. The influence of vehicle yaw on occupant kinematics has been well established. The role that the vehicle yaw has with regard to occupant injury potential is dependent upon a number of factors, including delta-V, vehicle intrusion, occupant seating position, restraint use, and yaw rate. Assuming rotation about the vehicle center of gravity or trivializing post-impact rotation may overlook aspects of the collision dynamics that have important implications for post-impact occupant motion. This study examines the significance of vehicle yaw on occupant kinematics and the evaluation of injury potential in eccentric planar collisions. The paper describes the calculation of the
Rapp van Roden, Elizabeth, Zolock, John
Road Rough Estimation for Autonomous Vehicle Based on Adaptive Unscented Kalman Filter Integrated with Minimum Model Error Criterion2022-01-00773/29/2022
The accuracy of road input identifiaction for autonomous vehicles (AVs) system, especially in state-based AVs control for improving road handling and ride comfort, is a challenging task for the intelligent transport system. Due to the high fatality rate caused by inaccurate state-based control algorithm, how to precisely and effectively acquire road rough information and chose the reasonable road-based control algorithm become a hot topic in both academia and industry. Uncertainty is unavoidable for AVs system, e.g., varying center of gravity (C.G.) of sprung mass, controllable suspension damping force or variable spring stiffness. To tackle the above mentioned, this paper develops a novel observer approach, which combines unscented Kalman filter (UKF) and Minimum Model Error (MME) theory, to optimize the estimation accuracy of the road rough for AVs system. A full-car nonlinear model and road profile model are first established. Secondly, a MME criterion is proposed to deal with the
Wang, Zhenfeng, Yang, Jiansen, li, xin, Li, HongLiang
Active control of Camber and Toe angles to improve vehicle Ride Comfort2022-01-11203/29/2022
This paper is part of the European OWHEEL project. It proposes a method to improve the comfort of a vehicle by adaptively controlling the Camber and Toe angles of a rear suspension. The purpose is achieved through two actuators for each wheel, one that allows to change the Camber angle and the other the Toe angle. The control action is dynamically determined based on the error between the reference angle and the actual angles. The reference angles are not fixed over time but dynamically vary during the manoeuvre. The references vary with the aim of maintaining a Camber angle close to zero and a Toe angle that follows the trajectory of the vehicle during the curve. This improves the contact of the tire with the road. This solution allows the control system to be used flexibly for the different types of manoeuvres that the vehicle could perform. An experimentally validated sports vehicle was used to carry out the simulations. The original rear suspension is a Trailing-arm suspension. It
Marotta, Raffaele, Strano, Salvatore, Terzo, Mario, Tordela, Ciro, Ivanov, Valentin
An Autonomous Steering Control Scheme for Articulated Heavy Vehicles Using Non-Linear Model Predictive Control Technique2022-01-03443/29/2022
This article presents an autonomous steering control scheme for articulated heavy vehicles (AHVs). Despite efficient freight transportation in economic and environmental benefits, AHVs exhibits poor low-speed maneuverability and low high-speed lateral stability due to their multi-unit vehicle configurations, large sizes, high centers of gravity. In addition, North America’s harsh weather during winters makes the scenario more challenging. AHVs often experience amplified lateral motions of trailing vehicle units in transient curved path negotiations. Heavy goods vehicles represent a 7.5 times higher risk than passenger cars in highway operation. Moreover, human driver errors cause about 94% of traffic collisions. However, little attention has been paid to autonomous steering control of AHVs. To increase the safety of AHVs, an autonomous steering control scheme is designed for a tractor/semi-trailer using a non-linear model predictive control (NLMPC) technique. To this end, a 4 degrees
Sharma, Tarun, Huang, Wei, He, Yuping
Validation of Utilizing a Self-Propelled Crash Sled to Simulate Occupant Accelerations in Minor Rear-End Impacts2022-01-10403/29/2022
A novel, electrically self-propelled, mobile, free-standing crash sled was constructed with a relatively minimal budget (i.e., ≤ $10,000). The crash sled was designed to simulate occupant driver or passenger seat movement in minor impacts at varying angles with minimal, if any, component replacement necessary between tests. Validation of the crash sled in a rear-end only configuration for determination of occupant accelerations was performed. Minor rear-end crash tests involving human occupants were conducted utilizing a 2007 Toyota Camry target vehicle and a 2005 Toyota Camry bullet vehicle with changes in velocity for the target vehicle ranging between 2.8 km/h and 7.7 km/h. Vehicle instrumentation consisted of tri-axial accelerometers affixed to the center tunnels near their respective center of gravities. Human occupant instrumentation occurred only in the target vehicle and involved tri-axial accelerometers at the head, thorax, and lumbar spine. Peak longitudinal head and lumbar
Vigil, Cole Mackenzie, Salboro, Conrad, Jones, Brian, Brink, Justin, Jorgensen, Michael, Swinford, Scott
AOC AIR-GROUND DATA AND MESSAGE EXCHANGE FORMATARINC633-4 (Current)11/30/2021
The purpose of ARNC 633 is to specify the format and exchange of Aeronautical Operational Control (AOC) communications. Examples of ARINC 633 AOC Structures/Messages include: Flight Plan, Load Planning (i.e., Weight and Balance and Cargo Planning Load Sheets), NOTAMs, Airport and Route Weather data, Minimum Equipment Lists (MEL) messages, etc. The standardization of AOC messages enable the development of applications shared by numerous airlines on different aircraft types. Benefits include improved dispatchability and reduce operator cost.
Airlines Electronic Engineering Committee
Steering Control Systems - Heavy TrucksJ2425_202111 (Current)11/9/2021
This SAE Recommended Practice describes a laboratory test procedure and requirements for evaluating the characteristics of heavy-truck steering control systems under simulated driver impact conditions, as well as driver entry/egress conditions. The test procedure employs a torso-shaped body block that is impacted against the steering wheel.
Truck Crashworthiness Committee
DESIGN AND FABRICATION OF VEHICLE ROLLOVER PREVENTION SYSTEM BY COUNTER STEERING MECHANISM IN AUTOMOBILE2021-28-015510/1/2021
Rollover prevention plays an important role in stability of the vehicle. About 35% percentage of accidents are caused due to rollover .Therefore this brings a need to prevent accidents caused by roll-over of vehicles. So this system prevents the eventual roll-over of the vehicle by a method of counter steering which turns or moves the vehicle in the direction where an eventual roll-over is occurring by applying a physical principle of neutral equilibrium which is displacing an object while not changing the position of its center of gravity .Counter steering brings the vehicle into a neutral equilibrium state thus avoiding the rollover. The rollover is sensed by the MPU-6050 accelerometer cum gyroscope sensor which detects the roll angle, roll acceleration of the vehicle. The programming is done for the ATMEGA controller using Arduino IDE software for continuous monitoring of roll angle and roll acceleration of the vehicle. When the roll acceleration or the roll angle exceeds the
Dhayaneethi, Sivaji, Deepan Kumar, Sadhasivam, S, Arulkumar, SUDHAN, V R, Vignesh, M, Boobalan, Saravanan
Suspension Components Calculation at Concept Stage to Evaluate the Ride and Handling Characteristics2021-26-00829/22/2021
Vehicle handing and ride are the critical attributes for customers while buying new passenger vehicle. Hence it is very important to design suspension which meets customer expectations. Often tuning of suspension parameters is very difficult at later stage like wheelbase, vehicle center of Gravity and other suspension parameters like roll center heights etc. A parametric mathematical model is built to study the effect of these parameters of vehicle handling and ride attributes at concept stage. These models are used to calculate the suspension ride rates, spring rates and Anti roll bar diameters for meeting target vehicle ride and handling performance. The model also calculates natural frequency of suspension and vehicle for understanding pitch and roll behaviours. The inhouse tool developed is used for calculating suspension damper characteristics and predicts ride attributes like Bounce damping, bounce stiffness, Isolation level, Flat ride and Impact Hardness categorized based on
Saifee, Aliakbar, Deshmukh, Chandrakant, deole, Subodh
Influence of Powertrain Mount Stiffness Progressivity on Buzz, Squeak & Rattle Noise for Electric Vehicle2021-01-10898/31/2021
For a modified electric vehicle on the same internal combustion engine (ICE) platform, the primary consideration is to have no change in long member and pendulum type conventional engine mounting system to save development cost and timeline. Electric vehicle (EV) powertrain is comparatively lighter w.r.t the ICE. As a result, the engine mount’s static preload setting point or powertrain centre of gravity under static powertrain load gets changed resulting in a change in stiffness for the same engine mount. As the static stiffness changes, the dynamic stiffness and modal frequency also change. The 6 degrees of freedom (DOF) modal frequency has almost no impact on powertrain modes as EV powertrain modes, mainly, the motor frequency, is much higher than engine mount Eigen modes. In this scenario, the gap management gets disturbed due to less static preload, and non-linearity gets affected. This paper will explain a case study on a modified EV, the change in modal map, its impact vis-a-vis
Hazra, Sandip, K, Janardhan Reddy
Design and Performance Criteria Aircraft Crash AxesAS5402A (Current)4/23/2021
This SAE Aerospace Standard (AS) provides design criteria and performance tests for crash axes intended for use by aircraft crew members to assist in evacuation, extrication, fire fighting, or other emergency activities.
S-9A Safety Equipment and Survival Systems Committee
Vibration Analysis of an Electric Vehicle Mounting System under Transient Shock Conditions2021-01-06644/6/2021
Electric vehicle motors have the characteristics of fast torque response, large amplitude, and braking feedback torque. Therefore, the excitation of the electric vehicle powertrain has obvious transient impact characteristics, which put forward new requirements for the design of the mounting system. This article carried out the real vehicle test of rapid acceleration and rapid deceleration. A 12-degree-of-freedom nonlinear dynamic model of the electric vehicle mounting system is established. The model is used to calculate the vibration acceleration of the active side and the passive side of the mount, and compared with the test value to verify the correctness of the simulation model. The impact degree, the maximum pitch angle of the powertrain, and the longitudinal acceleration of the powertrain centroid are used as evaluation indicators to analyze the transient response of the electric vehicle mounting system under rapid acceleration and rapid deceleration conditions. The influence of
Xiao, Bing, Wang, Minghui, Jiang, Yongfeng, Kang, Yingzi
Traction Control System of Electric Vehicle with 4 In-Wheel Motors using Lyapunov Stability Analysis Algorithm2021-01-01224/6/2021
A TCS strategy of electric vehicle with 4 in-wheel motors is proposed in this paper. The control method consists of three parts: target slip rate calculation, target torque calculation and coordination control. By using Lyapunov stability analysis algorithm, the target slip rate boundary which makes the system stable is obtained. The target torque of each wheel is calculated by PI controller. According to the engineering experience, the TCS coordinated control strategy under split friction coefficient (split-μ) road, and friction coefficient jump(μ jump) road is proposed. The test results show that this strategy can improve the acceleration comfort and yaw stability of vehicles on uniform low friction coefficient (low μ) , split-μ and μ jump road.
Zhao, Yongqiang, Hui, ZhouZehui, Cui, Jinlong
Standard Test Method for Measuring Forces During Normal Impact of a Soft Projectile on a Rigid Flat SurfaceAS6940 (Current)3/23/2021
This document describes a method for measuring forces during an impact between a soft or frangible projectile and a relatively rigid flat normal surface. The document describes the hardware and instrumentation required, as well as the processing and data reduction required to compute force. In this test, a projectile impacts one end of a long cylindrical bar with flat ends, called a Hopkinson bar. The impact occurs on the centerline of the bar in the axial direction. The diameter of the cylindrical bar is large compared to the lateral dimension of the projectile so that, during and after the impact, the projectile material moves radially or backward, rather than extruding around the perimeter of the impact surface. The bar is instrumented with strain gages at some distance from the impacted end to measure the longitudinal strain in the bar. The bar must be sufficiently long so that the duration of the impact is less than the time it takes for the transient stress wave generated by the
G-28 Simulants for Impact and Ingestion Testing Committee
Hyperspectral Cameras and Data QualityTBMG-386293/1/2021
Hyperspectral imaging combines both imaging and spectroscopy. There are many different optical architectures that are used to make hyperspectral systems, but the end goal is the same – to make an image where each pixel in the image contains information from many spectral bands (many different colors or wavelengths).
Vehicle Transport Unit Load Device (ULD)ARP1554D (Current)11/30/2020
The tests are static in nature to minimize complexity and cost of required testing facilities. As far as practical, applied static loads should take into account the combined static and dynamic loads anticipated in service. It is intended that tests shall be non-destructive in nature and not result in damage unless ultimate load conditions are employed. Test equipment and methods of testing described are not meant to be restrictive. Alternate equivalent methods to accomplish the desired results may be employed. In selected cases, tests may be repeated under ultimate load conditions when required for substantiation of analytical data. If this becomes necessary, the parts deformed may be removed and replaced prior to the retest.
AGE-2 Air Cargo
Monitoring Gross Weight and Center of Gravity Position: A Review of the Challenges and Current Estimation ApproachesF-0076-2020-1627210/5/2020
Weight and balance activities are widely recognized and understood as important steps in the operation and maintenance of an aircraft to ensure safe and efficient flight. From the pilot's perspective, the operational limits and maneuverability of the aircraft are directly linked to the weight and balance of the aircraft. From a structural perspective, fatigue damage can vary significantly with center of gravity position and gross weight. In-flight center of gravity and gross weight estimation has been pursued for many years with varying success. One of the major challenges is the lack of data to verify an estimation model, since these parameters cannot be easily measured using sensors in flight. This paper reviews in detail the requirement and challenges of accurately monitoring center of gravity and gross weight. In addition, a survey of published work on the estimation of these values is provided. These efforts are divided into four categories: helicopter dynamic models, performance
Cheung, Catherine, To, Davis
Origami-Inspired Miniature ManipulatorTBMG-3783610/1/2020
Minimally invasive laparoscopic surgery, in which a surgeon uses tools and a tiny camera inserted into small incisions to perform operations, has made surgical procedures safer for both patients and doctors. Surgical robots further assist surgeons by allowing them to manipulate multiple tools at once with greater precision, flexibility, and control than is possible with traditional techniques. These robotic systems are extremely large, often taking up an entire room and their tools can be much larger than the delicate tissues and structures on which they operate.
Active roll stabilization introduced for Audi's large crossovers20AUTP10_0810/1/2020
Audi is fitting its largest crossover models with a new, active anti-roll system that the company said enhances cornering capability and reduces body roll without sacrificing ride comfort. Unlike other active anti-roll systems, Audi's electromechanical roll stabilization (eAWS) doesn't rely on hydraulics and is claimed to be “virtually maintenance-free.” Large crossovers and SUVs can be challenging to engineer with assertive vehicle dynamics because their weight and higher center of gravity typically mitigate against sporty cornering unless the suspension is uncomfortably stiff. But the powered anti-roll bars at each axle in the eAWS system permit a comparatively soft tune for the base suspension, firming cornering dynamics only when required.
Visnic, Bill
Air Cargo Unit Load Devices - Performance Requirements and Test ParametersAS36100C-TEST-REC (Historical)9/29/2020
This SAE Aerospace Standard (AS) defines the minimum performance requirements and test parameters for air cargo unit load devices requiring approval of airworthiness for installation in an approved aircraft cargo compartment and restraint system that complies with the cargo restraint requirements of Title 14 CFR Part 25, except for the 9.0-g forward ultimate inertia force of § 25.561 (b)(3)(ii).
AGE-2 Air Cargo
Air Cargo Unit Load Devices - Performance Requirements and Test ParametersAS36100C (Current)9/29/2020
This SAE Aerospace Standard (AS) defines the minimum performance requirements and test parameters for air cargo unit load devices requiring approval of airworthiness for installation in an approved aircraft cargo compartment and restraint system that complies with the cargo restraint requirements of Title 14 CFR Part 25, except for the 9.0-g forward ultimate inertia force of § 25.561 (b)(3)(ii).
AGE-2 Air Cargo
Aircraft Asset Lifecycle and Digital Data Standards OverviewAIR7501 (Current)9/18/2020
This SAE Aerospace Information Report (AIR) reviews technical, operational, and maintenance data being exchanged between key stakeholders in aerospace asset lifecycle and data standards available for such exchanges. It identifies gaps and non-availability of data standards in certain areas. The scope of the current document is limited to aircraft operations, maintenance and disposal stages post-build phase, and does not include the detailed interactions during the aircraft build phase.
G-31 Electronic Transactions for Aerospace Committee
History of Commercial Aircraft New Tire Qualification TestingAIR5651 (Current)9/18/2020
This SAE Aerospace Information Report (AIR) is intended to provide a historical account of testing methods used during the years for Commercial Aircraft New Tire certification.
A-5C Aircraft Tires Committee
Aircraft Asset Lifecycle and Digital Data Standards OverviewAIR7501-TEST-REC (Historical)9/18/2020
This SAE Aerospace Information Report (AIR) reviews technical, operational, and maintenance data being exchanged between key stakeholders in aerospace asset lifecycle and data standards available for such exchanges. It identifies gaps and non-availability of data standards in certain areas. The scope of the current document is limited to aircraft operations, maintenance and disposal stages post-build phase, and does not include the detailed interactions during the aircraft build phase.
G-31 Electronic Transactions for Aerospace Committee
Annual Product Guide20TOFHP06_126/1/2020
Flexure Testing of Hydraulic Tubing Joints and Fittings by Planar Resonant Vibration (Free-Free Beam)AIR1529B (Current)5/6/2020
This Aerospace Information Report (AIR) establishes flexure test procedures to determine and classify the fatigue strengths of reconnectable or permanent hydraulic tube joints. The procedure is intended for conducting flexure tests of fittings and joints for hydraulic tubing materials such as AMS 5561 steel, AMS 4944 titanium and MIL-T-7081 aluminum alloy, mounted as free-free resonant beams. Of particular advantage are the inherent simplicity of test setup, minimum restraint from a test fixture, low power requirements, short test duration, and ease of varying stress level.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Aerospace - Passive Side Stick Unit General Requirements for Fly-by Wire Transport and BusinessARP6001B (Current)4/23/2020
This SAE Aerospace Recommended Practice (ARP) provides recommendations for design and test requirements for a generic “passive” side stick that could be used for fly-by wire transport and business aircraft. It addresses the following: The functions to be implemented The geometric and mechanical characteristics The mechanical and electrical interfaces The safety and certification requirements
A-6A3 Flight Control and Vehicle Management Systems Cmt
Fire Containment Cover - Operation and UseARP6905 (Current)4/23/2020
This SAE Aerospace Recommended Practice (ARP) provides guidelines for the effective operation and use of fire containment covers (FCCs). Technical Standard Orders (TSOs) C203 and C90e (and later revisions) incorporate AS6453, and provide the Minimum Performance Standards (MPS) for an FCC design. The net and pallet used with the FCC must be approved using the updated net and flammability requirements in TSO C90e and later revisions. However, fire containment performance also requires this equipment is properly used. Fire safety is compromised when FCCs are used in an inadequate manner.
AGE-2 Air Cargo
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