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串联弹性驱动器(SEA)被广泛地应用于机器人与环境、机器人与人的交互场景中,针对这种交互应用,本文提出了一种新型的有限时间输出反馈控制策略(FTOFC),保证SEA的输出力矩在交互过程中能够快速达到期望值/轨迹.具体而言,首先对SEA的动力学模型进行了分析和变换;其次,基于有限时间控制理论,设计了有限时间扩张状态观测器和2阶滑模控制器,将两者结合实现了一种有限时间输出反馈控制策略,并对闭环系统的稳定性及信号有界性进行了严格的理论分析.相比于已有方法,本文方法有以下3个方面的优势:1)本文的控制方法适用于非线性SEA,更具有通用性;2)本文方法基于有限时间控制理论,具有更优的暂态响应性能;3)本文控制方法充分考虑了交互过程中负载端动力学可能会发生剧烈变化的情况,更适用于交互应用.为了验证以上3点,在自主搭建的单关节SEA交互机器人平台上进行了实验验证并与传统的级联PID方法进行了对比,结果表明本文设计的控制器能取得更好的控制效果,并且对外界干扰具有很强的鲁棒性.
The series elastic actuator (SEA) is widely used in the robot and the environment, robot and human interaction scenarios. For this interactive application, this paper presents a new finite time output feedback control strategy (FTOFC) to ensure the output of the SEA The torque can quickly reach the expected value / trajectory in the process of interaction.Firstly, the dynamic model of SEA is analyzed and transformed.Secondly, based on the finite-time control theory, the finite-time extended state observer and the second-order sliding mode Controller, combining the two to achieve a finite-time output feedback control strategy, and a rigorous theoretical analysis of the closed-loop system stability and signal boundedness.Compared with the existing methods, this method has the following three The advantages of the method are as follows: 1) The control method of this paper is suitable for nonlinear SEA, more generality; 2) The method based on finite time control theory has better transient response performance; 3) The control method of this paper fully considers the interaction process In the load end dynamics may occur drastic changes in the situation, more suitable for interactive applications.In order to verify the above 3 points, independently built SEA Interactive Robot Stage experimentally verified and compared with the traditional PID cascade method, the results show that the designed controller can achieve better control, and has strong robustness to external interference.