Robust Active Disturbance Rejection Control For Flexible Link Manipulator

Abstract

SummaryThis paper presents an advanced robust active disturbance rejection control (ADRC) for flexible link manipulator (FLM) to track desired trajectories in the joint space and minimize the link’s vibrations. It has been shown that the ADRC technique has a very good disturbance rejection capability. Both the internal dynamics and the external disturbances can be estimated and compensated in real time. The proposed robust ADRC control law is developed to solve the problems existing in the original version of the ADRC related to the disturbance estimation errors and the variation of the parameters. Indeed, these parameters cannot be included in the existing disturbances and then be estimated by the extended state observer. The proposed control law is based on the sliding mode technique, which considers the uncertainties in the control gains and disturbance estimation errors. Lyapunov theory is used to prove the closed-loop stability of the system. The proposed control strategy is simulated and tested experimentally on one FLM. The effect of the observer bandwidth on the system performance is simulated and studied to select the best values of the bandwidth frequency. The simulation and experimental results show that the proposed robust ADRC has better performance than the traditional ADRC.

Review on Modeling and Control of Flexible Link Manipulators

“…Pradhan and Subudhi (2020) proposed a nonlinear self-tuning PID controller to control the joint position and link deflection of the FLM subjected to varying payloads. Fareh et al (2020) presented robust active disturbance rejection control for FLM to solve joint trajectories tracking control problem and minimize the link's vibrations. Xu et al (2018) proposed a second order non-singular terminal sliding mode optimal control technique for a two-link flexible manipulator with uncertain model parameters.…”

“…(d) Active disturbance rejection control technique has an excellent disturbance rejection capability (Fareh et al, 2020) • Disadvantages (a) There is a problem of input delay in the feedback loop because the estimations of the system states are calculated based on the sensor reading.…”

A Novel Visual Sensor Stabilization Platform for Robotic Sharks Based on Improved LADRC and Digital Image Algorithm

“…where M is a Hurwitz matrix and G(η) is bounded, η ∈ R n , and M ∈ R n×n , the error η is uniformly ultimately bounded [27][28][29][30].…”

“…Suppose a general error dynamic system where is a Hurwitz matrix and is bounded, , and , the error is uniformly ultimately bounded [ 27 , 28 , 29 , 30 ].…”

Terminal Traction Control of Teleoperation Manipulator With Random Jitter Disturbance Based on Active Disturbance Rejection Sliding Mode Control

“…However, ADRC is subjected to two major problems, i.e., the disturbance estimation errors and parameter variations, which cannot be included in the lumped disturbance and then estimated with the extended observer. The estimation errors of the lumped disturbance are commonly neglected, while parameter variations of the control input are not considered [43]. As revealed from the former analysis, the sliding mode control exhibits insensitivity to external disturbance and parameter perturbation, which can remedy the defect of ADRC.…”