2自由度铰接车体车辆越障偏移饱和控制

Obstacle negotiation yawing control of a 2-DOF articulated vehicle with actuator saturation

针对2自由度铰接车体车辆直线越障偏移问题,建立车辆越障运动的动力学模型.以后车体绕z轴的角速度、沿y轴速度和前车体相对后车体的横摆角速度作为被控量,建立误差运动学模型,对误差系统进行稳定性和能控性分析.由于净转向力矩有上限,采用反步法设计系统的抗饱和控制器,对运动偏移控制中的液压转向机构输出饱和现象进行抑制.通过计算得到了在偏移控制过程中液压转向执行机构的净输出力矩随时间变化的曲线.结果表明:加入抗饱和控制器后,通过前后车体间的转向液压系统控制前后车体相对角速度,车辆越障运动时的y向偏移误差在5 s后收敛至0,前后车体夹角、后车体进方向的偏角也随时间逐渐收敛至0,车辆沿直线路径行进,证明抗饱和控制算法能有效地消除越障偏移误差.

To solve the problem of line path control when the 2-DOF articulated vehicle surmounting obstacle, the dynamical model is developed, the angle velocity φr of the rear body rotates about z axis, the velocity Yr along y axis and yaw velocity θ1 of the front body relative to the rear body are chosen as controlled variables, and the error kinematic model of the vehicle is developed, the stability and controllability of system are analyzed. Because the net moment provided by the hydraulic steering mechanism has the amplitude, an anti saturation controller is designed by backstepping method to suppress the output saturation of the hydraulic steering mechanism in the yawing control. After putting the anti-saturation algorithm in the error control system, it is shown that the error in y direction i converges to 0 in 5 seconds, also the angle θ1 and φr converge to 0. The tracking path of vehicle is beeline. The anti-saturation algorithm is verified to eliminate the yawing error effectively by the simulation. And the curve of net moment provided by the hydraulic steering mechanism is calculated in the process of the yawing control.