Integrated sliding mode control with input restriction, output feedback and repetitive learning for space robot with flexible-base, flexible-link and flexible-joint

Abstract

In the control of space robots, flexible vibrations exist in the base, links and joints. When building a motion control scheme, the following three aspects should be considered: (1) the complexity in dynamic modeling; (2) the low accuracy of motion control and (3) the simultaneous suppression of multiple flexible vibrations. In this paper, we propose a motion vibration integrated saturation control scheme. First, the dynamic model of space robot with flexible-base, flexible-link and flexible-joint is established according to the assumed modes method and Lagrange equation. Second, singular perturbation theory is used to decompose the model into two subsystems: a slow subsystem containing the rigid motions of base and joints as well as the vibration of links, and a fast subsystem containing vibrations of base and joints. Third, an integrated sliding mode control with input restriction, output feedback and repetitive learning (ISMC-IOR) is designed, which can track the desired trajectories of base and joints with −3 orders of magnitude accuracy, while suppressing the multiple flexible vibrations of base, links and joints 50%–80% and 37% performance improvement over ISMC-IOR-NV were achieved. Finally, the algorithm is verified by simulations.

Adaptive fractional-order integral fast terminal sliding mode and fault-tolerant control of dual-arm robots

“…where η i ∈(0,1) is the fractional order of the derivative and b i is a viscoelasticity coefficient. Combination of nonlinear viscosity (13) with fractional friction ( 14) leads to a nonlinear fractional-order model…”

“…Sliding mode control (SMC) [7][8][9][10][11][12][13][14][15][16][17][18], a robust control approach, is known to be effective in controlling manipulators. While possessing strong robustness against uncertainties and disturbances, SMC is, on the other hand, subject to some drawbacks, for instance, highly switching gains, long convergence time, and chattering in the response.…”

“…Similar to the goal of super-twisting SMC [12], logarithmic SMC introduces logarithm function in terms of states into control structure to reduce chattering of control signals [12]. Specifically, integral TSMC [13] is effective in alleviating chattering and improving further steady-state performance. Therefore, combining integral action into FTSMC is one of the feasible choices for controlling DARs.…”

“…While SMC-based algorithms [7][8][9][10][11][12][13][14][15][16][17][18] can maintain well the tracking performance, they lack the ability to adjust control parameters in response to large system uncertainties. As a remedy, adaptive control approaches have been integrated into the SMC.…”

Space Robot On-Orbit Operation of Insertion and Extraction Impedance Control Based on Adaptive Neural Network

“…Compared with sending astronauts into space to complete these tasks, space robots have stronger adaptability to the harsh space environment and need not the life support system needed to maintain the survival of astronauts. Their long working hours and high efficiency can greatly save the cost of space exploration and perform more complex tasks [1][2][3][4]. Therefore, it is of great significance to do research on space robots [5][6][7][8].…”