This work solves the safe trajectory tracking control problem of robot manipulators with actuator faults, uncertain dynamics, and external disturbance. Another key issue met in practical robot engineering, i.e., joint velocity measurement uncertainty is also investigated. A robust control framework is presented. In this approach, a novel reconstruction law is preliminarily developed to estimate velocity measurement uncertainty, while the estimation error is finite-time stable. An adaptive control law is then designed by using the joint position, the estimated velocity, and the reconstructed knowledge of velocity measurement uncertainty. The key advantage of this methodology is that actual joint velocity and any prior knowledge of actuator faults are not required. The effectiveness of this proposed scheme is experimentally validated on a real robot arm.

This study considers the global output‐feedback control for a class of switched stochastic non‐linear time‐delay systems under arbitrary switchings. By using the backstepping technique and choosing an appropriate Lyapunov–Krasoviskii functional, an output‐feedback controller independent of switching signals is constructed to render the closed‐loop system globally asymptotically stable in probability and the output can be regulated to the origin almost surely. Two simulation examples are provided to show the effectiveness of the designed controller.

This paper discusses the problem of finite-time stabilisation for a class of stochastic low-order nonlinear systems via output feedback. By generalising the adding a power integrator technique, constructing an implementable reduced-order observer and using the stochastic finite-time stability criterion, a finite-time output feedback controller is presented to guarantee that the closed-loop system is finite-time stable in probability. A simulation example is provided to verify the effectiveness of the proposed design method.

Global output feedback stabilisation problem for a class of stochastic feedforward non‐linear systems with state time delay is investigated in this study for the first time. By introducing the homogeneous domination approach in the stochastic system, constructing an implementable homogeneous reduced‐order observer and choosing an appropriate Lyapunov–Krasoviskii functional, an output feedback controller is designed to render the closed‐loop system globally asymptotically stable in probability and the output can be regulated to the origin almost surely. A simulation example is provided to show the effectiveness of the designed controller.