基于轨迹规划的平面三连杆欠驱动机械臂位置控制

针对中间关节为欠驱动的二阶非完整平面三连杆机械臂,提出一种基于轨迹规划的末端点位置控制策略.首先,建立系统的动力学模型,并根据几何关系利用差分进化算法求取所有连杆与目标位置相对应的目标角度;然后,根据驱动关节与欠驱动关节的耦合关系,采用时间缩放法和双向法分别规划两根驱动连杆的两条轨迹,并利用遗传算法优化合适的第1连杆中间位置,将两条轨迹拼接成一条完整可达轨迹;最后,设计滑模变结构控制器以跟踪完整可达轨迹,实现系统从初始位置到目标位置的控制目标.数值仿真结果表明了所提出控制策略的有效性.

Position control of planar three-link underactuated manipulator based on trajectory planning

This paper presents a position control strategy of the end-point based on the trajectory planning for a second-order nonholonomic planar three-link underactuated manipulator with a passive middle joint. Firstly, the dynamics model is built, and according to the geometry relationship, a differential evolution algorithm is used to calculate all link target angles corresponding to the target position. Then, according to the couple relationship between the active joint and passive joint, the time scaling method and bidirectional method are used to plan two trajectories of the two active links, respectively. And we connect the two trajectories to be a whole admissible trajectory based on the genetic algorithm by optimizing the suitable middle angle of the first link. Finally, we design a sliding mode variable structure controller to track the whole admissible trajectory, which can achieve the control objective of the system from an initial position to a target position. Numerical simulation results show the effectiveness of the proposed control strategy.