移动机器人关节末端残余振动增广自适应控制系统设计

Design of Adaptive Control System for Augmentation of Residual Vibration at Joint End of Mobile Robot

摘要:

移动机器人在高速运动时的时变摩擦效应会引起关节传动链弹性变形，其变形运行与关节加速度激励频率重合会产生振动现象，难以快速收敛关节末端残余振动，导致拟合残差波动范围较大。为此，设计移动机器人关节末端残余振动增广自适应控制系统。系统硬件设计采用自适应控制策略，其结构由传感器模块、中央微处理器等组成。传感器利用多种高精度传感器实时采集关节姿态信息并传输处理；参考输入模块通过 PLC 源型输入电路提供期望关节轨迹信息；隔离驱动器采用 SLMi823x 系列，具备多种保护机制；多模式谐振控制器能适应多种工作条件，抑制残留振动。针对移动机器人在高速运动时面临时变摩擦效应与传动链弹性变形的非线性耦合问题，引入增广自适应控制方法，通过将关节动力学模型转换到合适坐标系实现解耦，基于该模型引入增广自适应控制策略，使关节速度与位置趋近期望值，从而快速收敛并抑制关节末端残余振动。系统应用结果表明，该系统可有效抑制末端残余振动，获取的轨迹关键点坐标为（95mm，60mm，45mm）、关节机械角波动范围是[-20°-20°]，均与实验指标一致，且拟合残差在[-0.4°-0.4°]范围内波动，具有良好控制效果。

Abstract:

The time-varying friction effect of the mobile robot during high-speed movement can cause elastic deformation of the joint transmission chain. When the deformation operation coincides with the excitation frequency of the joint acceleration, vibration phenomena will occur. It is difficult to quickly converge the residual vibration at the end of the joint, resulting in a large fluctuation range of the fitting residual. Therefore, an adaptive control system for augmented residual vibration at the joint ends of mobile robots is designed. The hardware design of the system adopts an adaptive control strategy, and its structure consists of sensor modules, central microprocessors, etc. The sensor utilizes a variety of high-precision sensors to collect joint posture information in real time and transmit and process it. The reference input module provides the expected joint trajectory information through the PLC source-type input circuit. The isolated drive adopts the SLMi823x series and is equipped with multiple protection mechanisms. The multi-mode resonant controller can adapt to various working conditions and suppress residual vibration. Aiming at the nonlinear coupling problem of time-varying friction effects and elastic deformation of the transmission chain faced by mobile robots during high-speed movement, the augmented adaptive control method is introduced. Decoupling is achieved by converting the joint dynamics model to an appropriate coordinate system. Based on this model, the augmented adaptive control strategy is introduced to make the joint speed and position approach the expected value. It has never rapidly converged and suppressed the residual vibration at the joint ends. The application results of the system show that this system can effectively suppress the residual vibration at the end. The coordinates of the obtained trajectory key points are (95mm, 60mm, 45mm), and the fluctuation range of the joint mechanical Angle is [-20°-20°], all of which are consistent with the experimental indicators. Moreover, the fitting residual fluctuates within the range of [-0.4°-0.4°], showing a good control effect.