Tracking error constraint-based adaptive dynamic surface control of electro-hydraulic manipulator system

This paper discusses the nonlinear tracking control problem of electro-hydraulic manipulator system (EHMS) with tracking error constraints. A barrier Lyapunov function-based adaptive dynamic surface control (BLF-ADSC) method is employed in EHMS to improve the dynamic tracking performance in the presence of parameter uncertainties. The combination of barrier Lyapunov function with dynamic surface control is convenient for eliminating both the violation of tracking error constraints and the differential explosion of backstepping iteration. In order to reduce the model uncertainties of EHMS, adaptation law and discontinuous projection mapping are incorporated to estimate the uncertain parameters. As a result, the asymptotic convergence and ultimate boundedness of the tracking error in EHMS are derived through the theoretical derivation. Comparisons of simulation results show prescribed tracking accuracy and good transient response of the proposed method.