Reconfigurable control of flexible joint robot with actuator fault and uncertainty

Abstract

This paper presents the fault tolerant control (FTC) of a flexible joint robot using singular perturbation method in order to compensate for the lost performance due to the occurrence of actuator fault and the uncertainty. This FTC is based on Lyapunov redesign principle. The singular perturbation method is used to reduce the dynamic model of the flexible joint robot in a fast and slow subsystem. The time scale reduction of the flexible joint model is carried out when their joint stiffness is large enough and the singular perturbation parameter is set to zero. The fault-tolerant control structure in this paper is based on two parts. The first term described the composite control for the system without defect and without uncertainty which represents the sum between slow and fast controllers. While the second term of the fault tolerant command describes additive control designed to compensate for the fault effect of the actuator on the uncertain system. The additive approach is based on the Lyapunov theorem, which guarantees asymptotic stability despite the presence of actuator defects and the parametric uncertainty. The theoretical results are applied on a robot manipulator with a single flexible joint.

Dynamic analysis and decoupled control of a heavy-duty walking robot with flexible feet based on super twisting algorithm

“…where q d , _ q d , € q d are the ideal position, velocity and acceleration signals, respectively; u is the controller output; K P , K D are the proportional and derivative gain matrices, respectively, which are diagonal and positive definite. Equation (20) can be obtained by substituting equation (19) in to equation (9): Equation (20) can be expressed in the form of state space: where X = e _ e T Â Ã , A = 0 I; ÀK P À K D ½ .According to the exponential algorithm, equation (22) can be obtained:…”

“…17,18 Yang et al 17 established the rigid-flexible coupling model of a 6-DOF Stewart platform with flexible joints in ADAMS and MATLAB, and the explicit dynamic equations are established based on the pseudo-rigid-body model and the principle of virtual power. Elghoul 19 proposed a fault-tolerant control method of a flexible joint robot to compensate for the lost performance due to the uncertainty. The singular perturbation method was used to reduce the dynamic model of the flexible joint robot in a fast and slow subsystem.…”

Disturbance observer‐based output feedback control of hydraulic servo system considering mismatched uncertainties and internal pressure dynamics stability

“…For example, in [37], the singular perturbation method was employed to obtain the scalable and computationally efficient model of voltage-source converter. The robot flexible-joint manipulator model was established with singular perturbation method in [38]. The model reduction issue for the linear system with Lévy noise was discussed in [39].…”

An improved control strategy based sliding mode approach for high-order systems with mismatched disturbances

“…The matched disturbance corresponds to the case where the disturbance is acting through the same channels as control inputs. This kind of disturbance is common in a large class of linear and nonlinear systems, such as robots [2][3][4][5], and aerial vehicles [6][7][8]. To overcome the effects of this category of disturbance, many control schemes have been proposed, for instance, H ∞ control [9,10], and sliding mode control [11,12].…”