End-Effector Trajectory Tracking Control of Space Robot withL2Gain Performance

Abstract

This paper presents a novel solution to the control problem of end-effector robust trajectory tracking for space robot. External disturbance and system uncertainties are addressed. For the considered robot operating in free-floating mode, a Chebyshev neural network is introduced to estimate system uncertainties and external disturbances. An adaptive controller is then proposed. The closed-loop system is guaranteed to be ultimately uniformly bounded. The key feature of this proposed approach is that, by choosing appropriate control gains, it can achieve any given small level ofL2gain disturbance attenuation from external disturbance to system output. The tracking performance is evaluated through a numerical example.

Tracking Control of Robotic Manipulators With Uncertain Kinematics and Dynamics

“…To quantify this objective, let m d   x be a desired known task-space trajectory in the path independent workspace W of the considered robot manipulator, and define a task-space tracking error as (5) Then, the control objective can be stated as follows: Consider the serial robotic manipulators with their dynamics and kinematics described by (1) and (3), respectively; design a control scheme and implement it by tuning control gains to guarantee that the actual robot trajectory x is always within the workspace W and thus away from singular configuration (hence, the corresponding kinematic singularities associated with ( ) J q can always be avoided); moreover, the tracking error 1 e is governed to zero vector in finite time.…”

“…To further evaluate the performance of the proposed double sliding mode observers-based control approach (DSMOBC), it is compared with the classical PID control [44], the 2 -gain-based adaptive control (L2BAC) [5], and the nonsingular terminal sliding mode control (NTSMC) [24] by using the following two performance indices:…”

“…It should be stressed that, high-accuracy control needs to be achieved in many applications. Motivated by this, many approaches inspired by modern control theories have been presented for robotic manipulators [5,6].…”

“…For the latter, the control law was synthesized by using sliding mode control technique. The main contributions of this paper are: (a) in comparison with the existing schemes in literature for the attenuation of uncertain kinematics/dynamics such as  2 -gain-based methods [5,6], adaptive control-based scheme [7], and sliding mode control-based scheme [11], the proposed approach can follow the desired trajectory with zero tracking error after finite time rather than with asymptotic convergence only, a faster tracking control is thus achieved, (b) compared with the previous work, the "linearity-in-parameters" assumption for the uncertain dynamics is not necessary, disturbances and uncertain moment-in-inertia in the dynamics of manipulator are also addressed; (c) the sliding mode observers proposed can achieve finite-time estimation when comparing with the existing observer-based estimation schemes [34] for robotic manipulators. This paper is organized as follows.…”

Finite-time adaptive control for the dual-arm space robots with uncertain kinematics, dynamics and deadzone nonlinearities

“…17,18 Kolhe et al 19 proposed a controller for single-arm space robots by designing a disturbance estimator and an uncertainties estimator to resist external disturbances and system uncertainties, and the stabilization of bases can be guaranteed in the meantime. Besides, in Zhang et al, 20 an adaptive control scheme is proposed to permit single-arm space robots precisely tracking trajectories, where the dynamic uncertainties are estimated by a NN. Further, Zhou et al 21 incorporates a linear switching surface into robust controllers to cope with both kinematic and dynamic uncertainties.…”