Abstract: Aiming at the problem that the body of the distributed drive unmanned vehicle inclines outward under the centrifugal force when steering, which causes the loads of the inner wheels to decrease, the failure of the differential steering, and even the rollover of the vehicle in serious cases, a trajectory tracking and vehicle body attitude control method for the differential steering unmanned vehicle was proposed. The proposed method could achieve the trajectory tracking of the unmanned vehicle through the differential steering and meanwhile achieve actively inward tilting the vehicle body during the steering through the active suspension to ensure the effectiveness of differential steering, which improved the handling stability of the unmanned vehicles. Firstly, a vehicle model and reference model considering roll factors were established, and the reference front wheel steering angle required for the reference model to track the desired path was obtained through a fractional order single point preview driver model. Then, on this basis, an H∞ robust controller was designed, the reference values provided by the reference model were tracked respectively through the control of the yaw rate and body inclination angle of the differential steering unmanned vehicle. Finally, the required differential driving torque and the left and right active suspension control forces were obtained. The research results show that the designed fractional order single point preview driver model and H∞ robust controller can effectively ensure that the differential steering unmanned vehicle can achieve trajectory tracking and vehicle body attitude control at the same time.

Key words: vehicle engineering; distributed drive unmanned vehicle; trajectory tracking control; vehicle body attitude control; differential steering; active suspension; H∞ robust control

摘要： 针对分布式驱动无人车转向时车身在离心力作用下外倾，引起内侧车轮载荷减小，严重时会导致差动转向失效乃至车辆侧翻等问题，提出了一种差动转向无人车的轨迹跟踪和车身姿态控制方法；该控制方法可通过差动转向实现无人车轨迹跟踪，同时通过主动悬架实现转向时车身主动内倾来保证差动转向有效性，提高了无人车的操纵稳定性。建立考虑侧倾因素的车辆模型及参考模型，通过分数阶单点预瞄驾驶员模型得到了参考模型跟踪期望路径所需的参考前轮转角；基于此，设计了H∞鲁棒控制器，通过控制差动转向无人车的横摆角速度和车身内倾角，分别跟踪参考模型提供的参考值，得到了所需的差动力矩及左右侧主动悬架控制力。研究结果表明：所设计的分数阶单点预瞄驾驶员模型和H∞鲁棒控制器能有效保证差动转向无人车实现轨迹跟踪，同时实现了车身姿态控制。

关键词: 车辆工程；分布式驱动无人车；轨迹跟踪控制；车身姿态控制；差动转向；主动悬架；H∞鲁棒控制