基于迟滞逆补偿的气动人工肌肉并联机器人同步控制

Hysteresis Inverse Compensation-based Synchronous Control for a Pneumatic Artificial Muscle-actuated Parallel Robot

  • 摘要: 虽然气动人工肌肉并联机器人兼具刚柔耦合特性,但是其控制精度易受到气动人工肌肉中迟滞特性的影响,且整体控制性能还会受制于所有机械臂的协调能力。为此,本文提出了一种基于迟滞逆补偿的同步控制方法,以实现气动人工肌肉并联机器人的期望跟踪性能。具体而言,改进Bouc-Wen迟滞模型以更准确地表征气动人工肌肉的输入-输出关系,并使用对应的逆模型进行前馈补偿,提高控制精度。同时,建立机械臂之间的误差信号传递,提升机械臂的运动同步性。然后,充分考虑气动人工肌肉并联机器人的全驱特性,在全驱系统方法框架下设计自适应气压控制器,确保跟踪误差和同步误差渐近收敛。最后,完成闭环系统的稳定性分析,并基于硬件平台进行了迟滞拟合对比测试和运动控制对比测试。对比结果表明所提迟滞模型的拟合精度和所提控制方法的跟踪精度均优于对比方法,充分验证了所提方法的可行性。

     

    Abstract: Although pneumatic artificial muscle-actuated parallel robots have both rigid and compliant characteristics, their control accuracy is easily affected by the hysteresis characteristic in pneumatic artificial muscles, and the overall control performance depends on the coordination abilities of all robotic arms. Therefore, a hysteresis inverse compensation-based synchronous control method is proposed in this paper, to achieve the expected tracking performance of pneumatic artificial muscle-actuated parallel robots. Specifically, the Bouc-Wen hysteresis model is modified to accurately express the input-output relationship of pneumatic artificial muscles, and the control accuracy can be improved by applying the corresponding inverse model to feedforward compensation. Meanwhile, the motion synchronization can be enhanced by establishing the error signal transmission between robotic arms. Then, an adaptive pressure controller is designed in the framework of fully actuated system approaches because of the fully actuated characteristic of pneumatic artificial muscle-actuated parallel robots, to ensure the asymptotic convergence of tracking errors and synchronization errors. Finally, the stability analysis of the closed-loop system is completed, and comparative tests of hysteresis fitting and motion control are conducted on the hardware platform. The comparative results show that the fitting accuracy of the proposed hysteresis model and the tracking accuracy of the proposed control method are superior to the comparative method, fully verifying the feasibility of the proposed method.

     

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