Speed control strategy of dual flexible servo system considering time‐varying parameters for flexible manipulator with an axially translating arm

Abstract

Many factors lead to fluctuations of output speed in the motor side during the movement processes in a flexible manipulator with an axially translating arm. These factors include the time‐varying characteristics of manipulator parameters, external disturbance, and flexibility in the manipulator. The vibration of flexible manipulators is strengthened by fluctuations of output speed, which seriously affects the motion accuracy. Therefore, a variable parameters proportional–integral (PI) control strategy based on disturbance observer is adopted to reduce fluctuations of output speed in a dual flexible servo system. First, the dynamic model of the dual flexible servo system is established by the assumed mode method. Then, the variable parameters PI control strategy is applied to the servo system, and the controller parameters in different conditions are selected by pole placement strategies. Finally, numerical simulations and control experiments of the servo system are carried out. The results show that the control strategy using the variable parameters and disturbance observer could reduce fluctuations of output speed and improve the motion accuracy of flexible manipulators.

Advances in Flexible Robotic Manipulator Systems — Part II: Planning, Control, Applications, and Perspectives

“…1) Proportional-Integral-Derivative (PID) Control: Sarkhel et al [55] used a PID controller for vibration suppression in a fishing rod-type FRM and explored the best location to place the controller along the flexible rod. Shang et al [56] developed a tunable PI controller, wherein the key parameters in the controller are dynamically tuned online by AMM-based pole placement.…”

Adaptive visual servoing for the robot manipulator with extreme learning machine and reinforcement learning

“…At present, intelligent control technology and robust control methods for robots have received extensive research [1][2][3][4]. Utilizing visual sensors as the feedback unit for robots is known as visual servoing, which is now widely applied in mobile robots control [5], underwater robot attitude control [6], unmanned aerial vehicle (UAV) attitude control [7,8], and plant harvesting [9].…”

Vibration control of the flexible manipulator with input constraints and external disturbances based on Nussbaum function

“…As a result, the angle tracking and vibration inhibition of the flexible manipulator have received extensive attention from scholars. Different control laws are proposed to solve this question, for example, PID control [2], adaptive control [3,4], sliding mode control [5,6], neural network control [7], and fuzzy control [8]. However, these traditional control methods are mainly based on with finite-dimensional truncation model described by the ordinary differential equations (ODEs), which ignores some high-frequency modes, leading to model information loss and control spillover problems so as to reduce the control accuracy [9].…”