Fuzzy Adaptive Sliding Mode Impedance Control of Fracture Reduction Robot

Abstract

With the development of robotics, it will be possible for fracture reduction robots to replace doctors in performing surgery operations. The surgery accuracy and safety by the reduction robot is important. In order to compensate various uncertainties and nonlinear problems in the reduction robot impedance control system, this paper proposes a fuzzy adaptive sliding mode impedance control of the reduction robot, which includes force residual observer (FRO) and fuzzy adaptive sliding mode controller (FASMC). The FRO is used to estimate the external force between the reduction robot and the fractured musculoskeletal tissue in real-time, no force sensor is installed at the end-effector of reduction robot. The FASMC mainly includes three parts: linearizing the system by inverse dynamics and PD control, improving the system's robustness by the sliding mode control and fuzzy adaptive switching gain to reduce chattering, eliminating the nonlinear disturbance term of the system, and the normalized factor linear combination fuzzy system is used to compensate. The co-simulation of the fracture reduction robot shows that the FASMC impedance control method has a better steady-state position and force tracking accuracy, the steady-state position accuracy is -0.733 mm, and the steady-state force accuracy is -2.12 N. This paper provides an effective method for impedance control of the fracture reduction robot.

Force/position tracking control of fracture reduction robot based on nonlinear disturbance observer and neural network

“…The details of the robot system are described in author's previous publication. 10,11 The workflow of fracture reduction is shown in Figure 2:…”

“…16 A variable impedance control strategy based on the variation of external muscle loads is proposed, which enables the robot to offer compliant force output while utilising an adaptive fuzzy sliding mode position controller to improve position tracking accuracy. 10,11 Model-based experimental results indicate that under a maximum dynamic load of 200N, the reduction accuracy for position and orientation is within �1.1 mm and �0.4°, respectively. Nevertheless, there is still a requirement for further improvement in position tracking accuracy.…”

“…5 Currently, the control methods for fracture reduction robots include Host Computer Jog Control (HCJC), 6,7 master-slave control, 8,9 and automatic control. 10,11 Recent research in this field is partially summarised in Table 1. The reduction accuracy of HCJC and master-slave control methods relies on continuous fluoroscopy.…”

“…A long bone fracture reduction robot based on compliant actuators has been introduced, featuring the incorporation of a fuzzy‐based closed‐loop velocity feedback controller to provide the robot's output force with compliance while maintaining acceptable trajectory tracking accuracy 16 . A variable impedance control strategy based on the variation of external muscle loads is proposed, which enables the robot to offer compliant force output while utilising an adaptive fuzzy sliding mode position controller to improve position tracking accuracy 10,11 . Model‐based experimental results indicate that under a maximum dynamic load of 200N, the reduction accuracy for position and orientation is within ±1.1 mm and ±0.4°, respectively.…”

Adaptive variable impedance position/force tracking control of fracture reduction robot

“…In order to realize the robot to imitate the surgeon's compliant reduction to the patient and avoid the rigid collision of the robot to the patient resulting in secondary injury, adaptive impedance control is presented in this paper. The FASMC 37 is designed based on the motor current loop and is used as the reduction robot system controller. Meanwhile, the friction force compensation is performed on the control system.…”