Extended High-gain Observer based Adaptive Control of Flexible-joint Surgical Robot

Due to the surgical robot flexible joint state vectors are not all measurable, in order to reduce the effect of the modeling errors and nonlinear factors of the flexible-joint manipulator caused by gravity and friction, an extended high-gain observer (EHGO) based adaptive control algorithm is designed to perform the position tracking control of the flexible-joint manipulator. First, gravity and friction are fed forward to reduce the nonlinearity of the robotic manipulator. Secondly, an extended high gain observer is used to observe the angular velocity of the joint and correct compensation errors of gravity and friction in real time. Finally, EHGO based adaptive controller is used to eliminate the inertia parameter measurement errors of the dynamic model, and to achieve high precision position tracking control. Simulation experiments show that the proposed control method can improve the position tracking accuracy of the flexible-joint manipulator and restrain the flexible-joint vibration obviously, and thus verifies that the designed controller can meet the requirements of accurate tracking control of the surgical robot.