Design of a Friction Self-Compensation Control Law for Multi-Link Robot Using Adaptive Sliding Mode Control

(1)为了将滑模控制器应用于机器人控制中，设计了一种改进的滑模控制器，使其能够跟踪参考输入。将改进后的控制器应用于机器人实验。在机器人PID控制中，为了精确跟踪输入，输入模型被作为控制器的内模型。提出了一种自适应PID伺服控制器，用于模型辨识和模型自适应融合。为了消除摩擦干扰，根据类似的原理给出了自适应伺服控制器。为了抑制扰动，本文还利用双补偿器设计了一种强稳定自校正控制器。(2)实验结果表明，抖振是由机器人角速度估计中的噪声引起的，而减小抖振是滑模控制器设计中最重要的课题。证明了观测器的设计与滑模控制器中滑动超平面的设计是对偶的。利用对偶性，给出了一种新的观测器设计方案，并通过实验证明了新方法设计的观测器是有效的。(3)滑模控制器中切换律增益过大是引起抖振的另一个原因，但切换律增益必须大于扰动的上界。为了设计更小的增益，其他作者提出了一种自适应滑模变结构控制器来识别边界和自适应调整增益。本文提出了在自适应滑模控制器中采用PI型自适应律，并证明了该方法的有效性和稳定性，还提出了在自适应滑模控制器中采用PI型自适应律的自适应观测器，并证明了该方法的有效性和稳定性。

(1) In order to apply a sliding mode controller to robot control, a modified sliding mode controller isﾟCdesigned to follow a reference input. The modified controller is applied to robot in experiment. In robotﾟCcontrol, to track input exactly, the input model is included as an inner model in controller. An adaptiveﾟCservo controller is proposed to identify the model and to include the model adaptively. To cancel frictionﾟCdisturbances, an adaptive servo controller is given by a similar principle. Also to suppress disturbances, aﾟCstrongly stable self-tuning controller is derived from two-compensator scheme.(2) It is shown from experimental results that chattering, of which reduction is the most significantﾟCsubject in designing sliding mode controller, is caused by noise in estimating robot angle velocity and isﾟCreduced by improving the estimation using an observer. Designing the observer is shown to be dual toﾟCdesigning a sliding hyper plane in sliding mode controller. Using the duality, a new design scheme forﾟCobserver is given and the observer designed by the new method is shown to be effective in an experiment.(3) A large gain of switching law in sliding mode controller is another cause of chattering but the gainﾟCmust be larger than the upper bound of disturbances. To design a smaller gain an adaptive sliding modeﾟCcontroller to identify the bound and adaptively adjust the gain has been proposed by other authors. In thisﾟCproject, it is proposed to use P1-type adaptive law in the adaptive sliding mode controller and it is shownﾟCthat the proposed method reduces the chattering and the closed-loop stability is proved mathematically.ﾟCAlso proposed to use the PI-type adaptive law in an adaptive observer used in the adaptive sliding modeﾟCcontroller and a reduction of chattering is shown.