Adaptive vibration control for constrained moving vehicle-mounted nonlinear 3D rigid-flexible manipulator system subject to actuator failures

This paper proposes an active adaptive fault-tolerant control scheme for position tracking and vibration suppression of a constrained moving rigid-flexible manipulator system (RFMS) in three-dimensional (3D) space. The investigated RFMS comprises four parts: a vehicle, a rotatable base, a rigid link, and a flexible link, which is first modeled using nonlinear partial differential equations (PDEs) in terms of Hamilton’s principle. The system may suffer from unknown actuator faults, and the proposed control strategy can compensate for the faults without knowing the fault type and information. The displacement constraint of the vehicle can be ensured by using the barrier Lyapunov function. In the presence of unknown actuator faults and the displacement constraint, the angular position tracking of rigid link, flexible link and rotatable base, and vehicle position tracking can be realized. At the same time, the vibration of the flexible link can be effectively suppressed. The closed-loop system is proven to be asymptotically stable via employing the extended LaSalle’s invariance. Numerical simulations are carried out to verify the effectiveness of the proposed control protocol.