Huang Fang, Sang Hongqiang, Liu Fen, Han Rui
School of Mechanical Engineering, Tiangong University, Tianjin, 300387, China.
Tianjin Key Laboratory of Advanced Mechatronic Equipment Technology, Tiangong University, Tianjin, 300387, China.
Med Biol Eng Comput. 2025 Jan;63(1):251-265. doi: 10.1007/s11517-024-03198-6. Epub 2024 Sep 19.
The motion accuracy, compliance, and control smoothness for the surgical robot are of great importance to improve the safety of human-robot interaction. However, the end effector that interacts with soft tissue during surgery affects the dynamics of the robot. The control performance of the controller may be decreased if the changing dynamics are not identified and updated in time. This paper proposes a robust impedance controller for the redundant remote center of motion manipulator influenced by external disturbances, including external torque, uncertainties, and unmodeled terms in the dynamics. To achieve the desired impedance, a continuously switching sliding manifold is proposed. When the sliding manifold is driven to zero, the motion error will converge to a bounded region. This can overcome the adverse effects of external disturbances while guaranteeing motion accuracy and compliance. Chattering of the sliding mode control is alleviated through the formulated continuously switching sliding manifold and integrated nonlinear disturbance observer. Simulations and experiments demonstrate that the proposed controller has excellent motion accuracy, compliance, and control smoothness. This provides potential application prospects for the redundant surgical robot to guarantee safe human-robot interaction.
手术机器人的运动精度、柔顺性和控制平滑性对于提高人机交互的安全性至关重要。然而，手术过程中与软组织相互作用的末端执行器会影响机器人的动力学特性。如果不能及时识别并更新变化的动力学特性，控制器的控制性能可能会下降。本文针对受外部干扰（包括外部扭矩、不确定性和动力学中的未建模项）影响的冗余运动远程中心操纵器，提出了一种鲁棒阻抗控制器。为了实现期望的阻抗，提出了一种连续切换的滑动流形。当滑动流形被驱动到零时，运动误差将收敛到一个有界区域。这可以克服外部干扰的不利影响，同时保证运动精度和柔顺性。通过所制定的连续切换滑动流形和集成的非线性干扰观测器，减轻了滑模控制的抖振。仿真和实验表明，所提出的控制器具有优异的运动精度、柔顺性和控制平滑性。这为冗余手术机器人保证安全的人机交互提供了潜在的应用前景。
