Seyed Hossein Tamaddoni

Optimal preview game theory approach to vehicle stability controller design

Dynamic game theory brings together different features that are keys to many situations in control design: optimisation behaviour, the presence of multiple agents/players, enduring consequences of decisions and robustness with respect to variability in the environment, etc. In the presented methodology, vehicle stability is represented by a cooperative dynamic/difference game such that its two agents (players), namely the driver and the direct yaw controller (DYC), are working together to provide more stability to the vehicle system. While the driver provides the steering wheel control, the DYC control algorithm is obtained by the Nash game theory to ensure optimal performance as well as robustness to disturbances. The common two-degrees-of-freedom vehicle-handling performance model is put into discrete form to develop the game equations of motion. To evaluate the developed control algorithm, CarSim with its built-in nonlinear vehicle model along with the Pacejka tire model is used. The control algorithm is evaluated for a lane change manoeuvre, and the optimal set of steering angle and corrective yaw moment is calculated and fed to the test vehicle. Simulation results show that the optimal preview control algorithm can significantly reduce lateral velocity, yaw rate, and roll angle, which all contribute to enhancing vehicle stability.

Optimal vehicle stability control design based on preview game theory concept

In this paper, vehicle stability is represented by a cooperative dynamic game such that its two agents (players), namely, the driver and the direct yaw controller (DYC), are working together to provide more stability to the vehicle system. While the driver provides the steering wheel control, the DYC control algorithm is obtained by the well-known Nash game theory to ensure optimal performance as well as robustness to disturbances. The common bicycle model is put into discrete form to develop the game equations of motion. To evaluate the control algorithm developed, a nonlinear vehicle model along with the combined-slip Pacejka tire model is used. The control algorithm is evaluated for a lane change maneuver, and the optimal set of steering angle and corrective yaw moment is calculated and fed to the test vehicle. The simulation results show that the optimal preview control algorithm can significantly reduce lateral velocity and yaw rate which all contribute to enhancing vehicle stability.

Optimal VSC design based on Nash strategy for differential 2-player games

For optimal vehicle yaw stability control system development, inclusion of driver dynamics seems necessary. In this paper, a novel design approach is proposed for developing optimal solutions to vehicle stability control problems in the presence of the driver-in-the-loop steering models. The design concept is inspired by a Nash strategy for exactly known systems with more than two players. In the presented method, driver, controlling the steering wheel, and vehicle stability control unit, applying braking torques on the wheels, are defined as two dynamic players in a 2-player differential LQ game, and as a result, a novel control algorithm is developed. The results from a numerical simulation of a single lane change maneuver show the effectiveness of this controller over the common LQR control approach.

A New Control Algorithm for Vehicle Stability Control

A new control algorithm and the adaptation laws required for estimation of unknown vehicle parameters have been developed for vehicle stability control (VSC). This algorithm is based on the Lyapunov Direct Method. A vehicle model with two degrees of freedom (DOF) was used to develop the control algorithm. In developing the equations of motion for this simple model, a new approach for introducing the needed stabilizing forces and moments was developed. In addition, an eight DOF model was developed for control algorithm evaluation. The model includes lateral, longitudinal, yaw, and roll motions of the body plus the rotational DOFs for all of the four wheels. Also included in the model is a transient tire model taking into account the tire lateral relaxation length. Using the validated 8 DOF simulation model, the new control algorithm was evaluated and the results show the advantages of using such an approach for enhancing vehicle stability during emergency steering maneuvers.Copyright

Optimal vehicle stability controller based on Nash strategy for differential LQ games

This paper introduces a novel optimal vehicle stability controller in the presence of driver model. The concept is inspired by Nash strategy for exactly known systems with more than two players. In the presented method, the driver, commanding the steering angle, and the vehicle stability controller, applying compensated yaw moment, are defined as two players in a differential linear quadratic game. As a result, a novel optimal control algorithm is developed. Evaluated by a nonlinear vehicle model, numerical simulations are done for a single lane change manoeuvre, and preliminary results show the effectiveness of this controller over linear quadratic regulators.

Cooperative DYC system design for optimal vehicle handling enhancement

In many severe maneuvers, the driver-controller interaction seems necessary for maintaining a stable vehicle. This paper introduces a novel cooperative direct yaw control (DYC) design for optimal vehicle stability control in the presence of human driver. The interaction is defined by forming a differential linear quadratic game between the driver who is controlling the steering angle and the controller which is controlling the brake torques. Evaluated by a nonlinear vehicle model, numerical simulations are presented for a vehicle in the standard fishhook test. Preliminary results show the effectiveness of this controller over a commonly used linear quadratic controller.