Secure practical tracking of an uncertain robotic system under coarse conditions on reference trajectory and obstacles

Abstract

Abstract This article investigates practical tracking joint with obstacle‐avoidance for a class of uncertain robotic systems. The remarkable features are revealed from two aspects. First, more serious system uncertainties are allowed than the related literature due to the presence of unknown system matrices and mismatched disturbance in the investigated system. Second, only coarse conditions are required on reference trajectory and obstacles since their time derivatives are not necessarily to be available for feedback but those of the related literature muse be, while the reference trajectory is only required to be first rather than second order continuously differentiable. For this, a secure adaptive control framework is established by incorporating adaptive dynamic compensation mechanism into the backstepping procedure with the smart choice of adaptive law and the skillful injection of a barrier function. Consequently, a state‐feedback controller is explicitly designed which guarantees the obstacle‐avoidance of the robotic system while all the signals of the resulting closed‐loop system are bounded with system output practically tracking the reference trajectory. Finally, simulation results are provided for two specified robot systems to validate the effectiveness of the theoretical results.

Keywords

• adaptive control
• non‐linear control systems
• robots