绳索牵引并联机器人的双空间自适应同步控制

Dual-space Adaptive Synchronization Control of Cable-driven Parallel Robots

  • 摘要: 在绳索牵引并联机器人(CDPR)的运动过程中,关键的问题就是绳索必须保持张紧,且多根绳索之间需要相互协调.而且,模型参数的不确定性也会在一定程度上影响其运动控制,必须加以考虑.为了解决这些挑战,将绳长空间自适应同步与工作空间自适应补偿结合起来,提出了一种新型的双空间自适应同步控制器.通过绳长同步误差来表示绳索之间的协调运动,并通过双空间自适应的方法来实时补偿不同空间中的模型参数不确定性.随后,严格证明了双空间自适应同步控制系统的闭环稳定性.将实验结果与现有的增广PD控制器进行对比发现,提出的双空间自适应同步控制器可以显著地提高绳长的跟踪精度、改善绳索之间的协调关系,从而最终提高动平台的控制精度.同时,控制器中的自适应作用可以有效地补偿末端动平台的质量变化带来的影响.

     

    Abstract: The main challenge of cable-driven parallel robots (CDPRs) stems from the motion control in which cables should keep in tension and coordinate each other during motion. Moreover, the uncertain model parameters also should be considered due to their influences on the motion control to some extent. To solve the above problems, a novel dual-space adaptive synchronization control (DASC) scheme is proposed to combine the adaptive synchronization in the cable length space with the adaptive compensation in the workspace. In the DASC scheme, the cable synchronization error is presented to represent the coordination motion relation among cables, and a dual-space adaptive method is then developed to compensate for the uncertain model parameters in different spaces in real time. The stability of the closed-loop system with the DASC scheme is proved strictly. The experimental results indicate that, compared with the traditional augmented PD (APD) control scheme, the DASC scheme can greatly improve the tracking accuracy of cables and the coordination relation among cables, and eventually increase the control accuracy of the mobile platform. Meanwhile, the adaptive effect in the DASC scheme can effectively compensate for the impact of the mass change of the terminal mobile platform.

     

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