Yaw Moment Compensation Research Articles

Yaw Moment Compensation by Actuator-Based Control of Brake System in Automobiles

The growing use of brake systems in enhancing vehicle performance along with safety has promised a greater class of innovation. The presented research first discusses a vehicle dynamics model that accounts for the longitudinal and lateral forces acting on the wheels to compute the yaw moment acting on the vehicle based on the steering angle. Dynamic load transfer due to combined action of gravitational load, gyroscopic couple and centripetal force for real-time behavior is considered in the vehicle dynamics model. With a difference in theory and practice, work then focuses on the various disturbances that affect the dynamics of any vehicle under yawing action. The effect of wind disturbance is considered in-depth for the research and other factors like undesirable tire behavior have been discussed as well. For yaw moment compensation, a unique brake system layout with two circuits (primary & secondary), making the use of shuttle valves has been devised and a closed-loop control system is implemented. Each wheel is autonomously provided a brake force by an electromechanical actuator, computed by its respective PID controller to compensate for the variation in yaw moment caused due to external disturbances.

Fail-Operation Control of In-Wheel Motor Drive Electric Vehicle Based on Wheel Isolation and Yaw Moment Compensation

To improve the trackability of in-wheel motor drive (IWMD) and wheel-individual steer electric vehicles (EVs) when steering actuators fail, the fail-operation control strategy was proposed to correct vehicles in a steering failure situation and avoid losing control of vehicle steering. A linear quadratic regulator (LQR) decides the additional yaw moment of the vehicle according to vehicle state errors. The tire force estimation module estimates the compensating resistance moment generated by the failed wheel according to the tire slip angle and the vertical tire force. By isolating the failed wheel, the optimal torque distribution (OTD) controller allocates the additional yaw moment and the compensating resistance moment to normal wheels to realize the fail-operation control of the IWMD vehicle. The control effect was verified through co-simulation of MATLAB/Simulink and Trucksim. Compared with the uncontrolled and direct torque allocation methods, the proposed OTD method reduces the lateral trajectory error of the vehicle by 86% and 60.5%, respectively, when failure occurs, and achieves better velocity maintaining ability, which proves the effectiveness of the proposed fail-operation control strategy.

Walking With Arm Swinging and Pelvis Rotation Generated With the Relative Angular Acceleration

A natural-looking arm swinging in biped locomotion can be generated by appropriately controlling the quantities derived from the momentum equilibrium principle such as the rate of change of the relative angular momentum or the relative angular acceleration (RAA). The arm swinging compensates completely the undesirable yaw moment generated by the swing leg. The RAA control input can also be used to control the angular excursion of the pelvis that contributes to the compensation of the yaw moment, either in a passive or in an active way. It is shown that by varying the intensities of the arm swinging and the pelvis rotation, human-like gaits can be easily generated. The yaw-moment compensation strategies are implemented with a recently developed walking controller that distributes the body wrench with the so-called virtual repellent point (VRP) generalized inverse (VRP-GI). This controller is time-efficient since iterative computations are avoided. The performance of the controller in dynamic walking with arm swinging and passive/active pelvis rotation is confirmed via simulations.

Simultaneous Prevention of Rotational and Translational Slip for a Humanoid Robot

Slip often occurs in humanoid robot walking, especially when the robot walks on a low friction floor or walks fast. Unexpected slip may cause the robot to fall and then sustain damage. In real environments, rotational and translational slip phenomena can happen during biped walking. Previous studies have mainly focused on solving these problems independently. In this paper, we propose strategies for simultaneous rotational and translational slip prevention based on a three mass model, which takes into account the effect of the swing leg. The rotational slip is prevented through a bionic walking pattern generator which mimics the yaw moment compensation mechanism of a human. The translational slip is eliminated through a novel reaction force ratio reduction control with the compensation of CoM (center of mass) acceleration. The effectiveness of the presented strategies is validated by simulations and experiments with an actual humanoid robot.

Yaw Moment Compensation for Humanoid Robot via Arms Swinging

This paper investigates the problems of the z-axis dynamic balance and high energy consumption in practical application of humanoid robot. Considering z-axis dynamic balance conditions, a novel yaw moment compensation solu- tion based on arms-swinging is proposed by computing the optimal arms-swinging trajectories to counteract the yaw mo- ment caused by the movement of humanoid robot. Given the optimized arms-swinging motion, an adaptive control system is proposed to track the desired trajectories with model uncertainties. From the Lyapunov stability analysis, the adaptation law is induced and the uniformly boundness of all signals in a closed-loop adaptive system is proved. Simulation results validate the proposed method.

Modeling and control of an anti-lock brake and steering system for cooperative control on split-mu surfaces

The brake and steering systems in vehicles are the most effective actuators that directly affect the vehicle dynamics. In general, the brake system affects the longitudinal dynamics and the steering system affects the lateral dynamics; however, their effects are coupled when the vehicle is braking on a non-homogenous surface, such as a split-mu road. The yaw moment compensation of the steering control on a split-mu road is one of the basic functions of integrated or coordinated chassis control systems and has been demonstrated by several chassis suppliers. However, the disturbance yaw moment is generally compensated for using the yaw rate feedback or using wheel brake pressure measurement. Access to the wheel brake pressure through physical sensors is not cost effective; therefore, we modeled the hydraulic brake system to avoid using physical sensors and to estimate the brake pressure. The steering angle controller was designed to mitigate the non-symmetric braking force effect and to stabilize the yaw rate dynamics of the vehicle. An H-infinity design synthesis was used to take the system model and the estimation errors into account, and the designed controller was evaluated using vehicle tests.

Fast Walking Pattern Generation for Humanoid Robot Using Waist Joint Moment Compensation

In order to effectively improve humanoid robot’s dynamic walking capability, COM (center of mass) and ankle trajectories are generated by taking advantages of the gait generation method based on ZMP (zero moment point) preview control and introducing the rotation about the front rear edges of the stance foot. Furthermore, gradual decrease in the COM lateral swing amplitude and waist joint yaw moment compensation are used to get faster speed. Finally, the fast and dynamic walking of 3-D virtual humanoid prototype is realized in virtual physical environment by kinetic simulation software. The effectiveness of the proposed method is illustrated by simulation results.

Aircraft load alleviation by robust yaw-lateral decoupling

In an engine out/engine failure of an aircraft the human pilot has to compensate a yaw disturbance torque. Because of a delayed reaction possibly followed by an overreaction the pilot may cause high loads (shear forces) at the vertical tail. These shear forces determine the static design of the vertical tail in some areas and its structural weight. Such a situation and a corresponding weight increase can be avoided by an automatic yaw control system. It achieves a precise and early yaw moment compensation faster than the pilot can do it. To tackle both the load alleviation and the handling problem within the controller design, the yaw rate is made robustly non-observable from the lateral acceleration at a decoupling point and approximately from the shear force at the vertical tail. The parameters of the robust controller can be derived analytically. Nonlinear high precision simulations show that a significant load alleviation at the vertical tail is achieved and that the handling and the passenger comfort are improved.

Motion Control of Front-Wheel-Steering Vehicles by Yaw Moment Compensation. Comparison with 4WS Performance.

This paper proposes a new method to improve the handling and stability of vehicles by controlling the yaw moment generated by driving/braking forces. Yaw moment is controlled by the feedforward compensation of steering angle (and steering velocity) to minimize the side slip angle at the vehicle center of gravity. To realize this kind of yaw moment control, the right and left driving/braking forces should be controlled independently. Theoretical analysis and computer simulation are carried out to show the effectiveness of this control system. The results show that the handling and stability are improved significantly compared to those of the conventional two-wheel-steering vehicles, and that a 4WS-equivalent vehicle performance is obtained. This control effectiveness is also verified by experimental results using a downsized vehicle model on a moving belt tester.