THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

Autonomous vehicles have attracted more attention in recent years as vehicle applications are evolving to a more intelligent and autonomous stage. This paper presents the development of a collision avoidance system for an autonomous vehicle application which consists of a motion planner and model-predictive-control-based active vehicle steering and active wheel torque control. A motion planner, based on polynomial parameterization, determines a collision-free trajectory when a vehicle collision with obstacles is likely to happen. Then an MPC-based control system controls the front steering and individual wheel torques to track the desired collision-free reference trajectory. The proposed system is evaluated through simulation, using an eight-degrees-of-freedom vehicle model with a ‘magic formula’ tire model, active front steering, and active wheel torque distribution systems. The simulation results show that it effectively performs collision avoidance maneuvers.

Autonomous vehicle collision avoidance system using path planning and model-predictive-control-based active front steering and wheel torque control

A novel direct yaw moment controller is developed in this paper. A hierarchical control architecture is adopted in the controller design. In the upper controller, a driver model and a vehicle model are used to obtain the driver's intention and the vehicle states, respectively. The upper controller determines the desired yaw moment by means of sliding mode control. The lower controller distributes differential longitudinal forces according to the desired yaw moment. A nonlinear tyre model, ‘UniTire’, is utilised to develop the novel distribution strategy and the control boundary.

A novel direct yaw moment controller for in-wheel motor electric vehicles

In this paper, a coordinated control strategy is proposed to provide an effective improvement in handling stability of the vehicle, safety, and comfortable ride for passengers This control strategy is based on the coordination among active steering, differential braking, and active suspension systems Two families of controllers are used for this purpose, which are the high order sliding mode and the backstepping controllers The control strategy was tested on a full nonlinear vehicle model in the environment of MATLAB/Simulink Rollover avoidance and yaw stability control constraints have been considered The control system mainly focuses on yaw stability control When rollover risk is detected, the proposed strategy controls the roll dynamics to decrease rollover propensity Simulation results for two different critical driving scenarios, the first one is a double lane change and the other one is a J-turn manoeuvre, show the effectiveness of the coordination strategy in stabilising the vehicle, enhancing handling and reducing rollover propensity

https://hal.archives-ouvertes.fr/hal-01900441/document

Coordinated control strategies for active steering, differential braking and active suspension for vehicle stability, handling and safety improvement

This brief paper focuses on the concept of utilizing torque-biasing systems on a four-wheel drive vehicle for improving vehicle stability and handling performance. In contrast to brake-based yaw stability control systems, torque biasing has the potential to provide yaw stability control without slowing down the longitudinal response of the vehicle. An inexpensive system configuration is considered in which the driveline is based on front-wheel drive with on-demand transfer of torque to the rear. The torque-biasing components of the system are an electronically controlled center coupler and a rear electronically controlled limited slip differential. First, modeling of the torque-biasing devices is briefly introduced. Then, a hierarchical control architecture is presented in which an upper controller determines desired yaw moment for achieving yaw rate and slip angle control. The lower controller attempts to achieve the desired yaw moment using torque biasing. Theoretical analysis shows that transfer of longitudinal tire forces can effectively be used to achieve any desired yaw moment for the vehicle. However, the use of torque biasing cannot always achieve the desired transfer of longitudinal tire forces. Simulations show that the proposed control system can always effectively provide understeering yaw moments but can provide oversteering torque moments only during on-throttle maneuvers. Experimental data show that significant stability improvements are obtained using the proposed system for low-friction slalom maneuvers and a T-junction launch maneuver. The results presented in this brief shed important light on the possibilities and limitations of using torque biasing for vehicle yaw stability control

On the Use of Torque-Biasing Systems for Electronic Stability Control: Limitations and Possibilities

The sophistication of all-wheel-drive (AWD) technology is approaching the point where the drive torque to each wheel can be independently controlled. This potentially offers vehicle handling enhancements similar to those provided by dynamic stability control, but without the inevitable reduction in vehicle acceleration. Independent control of AWD torque distribution would therefore be especially beneficial under acceleration close to the limit of stability. A vehicle model of a typical sports sedan was developed in Simulink, with fully independent control of torque distribution. Box–Behnken experimental design was employed to determine which torque distribution parameters have the greatest impact on the vehicle course and acceleration. A proportional-integral control strategy was implemented, applying yaw rate feedback to vary the front–rear torque distribution and lateral acceleration feedback to adjust the left–right distribution. The resulting system shows a significant improvement over conventional dr...

Russell P. Osborn

Papers

Independent control of all-wheel-drive torque distribution

Independent control of all-wheel-drive torque distribution