Integrated Vehicle Yaw Moment Control System Using Active Momentum Wheel and Differential Braking

The yaw moment control is the most efficient method for improving vehicle handling and stability. A corrective yaw moment should be applied to the vehicle in order to modify the dynamic behaviour of vehicle. This corrective yaw moment is related to the interaction between the tires and road. Therefore generating corrective yaw moment independent from the tire-road interactions is noteworthy. In this research an innovative method for generating corrective yaw moment by using an external source which is independent from the tire-road interaction has been studied which is inspired from aerospace industry. This method generates yaw moment using a disk or vehicle’s spare tire used as a momentum wheel. In this paper the specification of this system, integration with direct yaw moment control and performance analysis of integrated and individual control systems have been studied. INTRODUCTION Generally, there are two main methods to control yaw moment, indirect and direct. The indirect yaw moment control works based on steering angle control. The direct yaw moment control almost works based on differential braking. The corrective yaw moment which is produced by these methods is related to the interaction between tire and the road and in low friction conditions like icy roads, performance of these methods noticeably reduced. An innovative idea for control yaw moment that named as The Controlled Moving Mass has been introduced previously [1]. The base of this idea is producing a corrective yaw moment which is independent from road/tire interactions. For approach to this goal, a controllable pendulum and a rotary actuator are attached to rear of the vehicle as a tail. In this paper, as a new idea, the pendulum has been replaced by a momentum wheel; this idea has been inspired from aerospace industry. Reaction and momentum wheels have become standard equipment for three-axis attitude stabilization of conventional satellite classes as used e.g. for telecommunication and remote sensing missions. A rigid spacecraft in general is controlled by three independent actuators and it is well known that three momentum wheels can be used to accomplish arbitrary reorientation manoeuvres of the spacecraft. Owing to very compact mechanical designs and highly integrated electronics, wheels are now also more and more interesting for small satellites [2, 3]. In this paper the momentum wheel has been used to control overall yaw moment of the vehicle. The most important benefit of this idea is vanishing of the unbalance effects of the previous system. In addition this idea has more feasible because the spare tire which located in the trunk of vehicle can be use as the rotational mass. VEHICLE WITH MOMENTUM WHEEL In this study two vehicle models with momentum wheel system have been considered, one being a linear model and the other a more complex nonlinear one. The linear model has been used to design the control system while the nonlinear model has been utilized to investigate the dynamic performance of the control system. LINEAR MODEL The proposed vehicle can be modeled using a well known bicycle configuration [4] which is incorporated with a momentum wheel at its end as shown in Fig. 1. The linear vehicle handling model consists of 3 degrees of freedom which are the vehicle yaw rate r1, lateral velocity v1 and the wheel angular rate r2. The momentum wheel system consists