A continuous finite-time control scheme for rigid robotic manipulators is proposed using a new form of terminal sliding modes. The robustness of the controller is established using the Lyapunov stability theory. Theoretical analysis and simulation results show that faster and high-precision tracking performance is obtained compared with the conventional continuous sliding mode control method.

/pdf/continuous-finite-time-control-for-robotic-manipulators-with-2a187yyli2.pdf

Continuous finite-time control for robotic manipulators with terminal sliding modes

http://www.ece.ualberta.ca/~tbs/pmwiki/pdf/CEP-Mohammadi-2012.pdf

Nonlinear Disturbance Observer Design For Robotic Manipulators

For a class of robot arms, a proportional-derivative (PD) controller plus gravity compensation yields the global asymptotic stability for regulation tasks, and some proportional-integral-derivative (PID) controllers guarantee local regulation without gravity cancellation. However, these controllers cannot render asymptotic stability for tracking tasks. In this paper, a simple decentralized continuous sliding PID controller for tracking tasks that yields semiglobal stability of all closed-loop signals with exponential convergence of tracking errors is proposed. A dynamic sliding mode without reaching phase is enforced, and terminal attractors, as well as saturated ones, are considered. A comparative experimental study versus PD control, PID control, and adaptive control for a rigid robot arm validates our design.

Dynamic sliding PID control for tracking of robot manipulators: theory and experiments

Disturbance observer (DOB) has been one of the most widely used robust control tools since it was proposed by Ohnishi in 1983. This paper introduces the origins of DOB and presents a survey of the major results on DOB-based robust control in the last 35 years. Furthermore, it explains DOB's analysis and synthesis techniques for linear and nonlinear systems by using a unified framework. In final section, this paper presents concluding remarks on DOB-based robust control and its engineering applications.

Disturbance Observer-Based Robust Control and Its Applications: 35th Anniversary Overview

In this brief, a new variable structure proportional-integral-derivative (PID) controller design approach is considered for the tracking stabilization of robot motion. The work corroborates the utility of a certain PID sliding mode controller with PID sliding surface for tracking control of a robotic manipulator. Different from the general approach, the conventional equivalent control term is not used in this controller because that needs to use the matching conditions and exact full robot dynamics knowledge, which involves unavailable parameter uncertainties. Though the sliding surface includes also the integral error term, which makes the robot tracking control problem complicated, the existence of a sliding mode and gain selection guideline are clearly investigated. Moreover, different from uniformly ultimately boundedness, the global asymptotic stability of the robot system with proposed controller is analyzed. The sliding and global stability conditions are formulated in terms of Lyapunov full quadratic form and upper and lower matrix norm inequalities. Reduced design is also discussed. The proposed control algorithm is applied to a two-link direct drive robot arm through simulations. The simulation results indicate that the control performance of the robot system is satisfactory. The chattering phenomenon is handled by the use of a saturation function replaced with a pure signum function in the control law. The saturation function results in a smooth transient performance. The proposed approach is compared with the existing alternative sliding mode controllers for robot manipulators in terms of advantages and control performances. A comparative analysis with a plenty of simulation results soundly confirmed that the performance of developed variable structure PID controller is better under than those of both classical PID controller and an existing variable structure controller with PID-sliding surface.

A new variable structure PID-controller design for robot manipulators

This paper presents an overview of robust control schemes for robot manipulators. The survey summarizes the vast literature on the subject. The different modelling assumptions used in current control algorithms are thoroughly reviewed. The survey includes models of actuator dynamics and joint flexibility. The different control schemes are organized in the following six categories: linear schemes, passivity-based schemes, Lyapunov-based schemes, sliding mode control schemes, non-linear H omega schemes and robust adaptive control schemes. Connections and comparisons are made between the various algorithms.

Robust control of robot manipulators: A survey

In this paper, the design of a position tracking control scheme for an industrial robot manipulator is considered. The design is based on the normalized left coprime factors robust stabilization approach. By coupling this H/sub /spl infin// synthesis to a sequential quadratic programming optimization procedure, a systematic design method is developed optimizing the performance of the controller. Further, the role of the nominal model for the design is explored. The control scheme is successfully implemented and tested on a real industrial robot manipulator. The computed controller worked immediately in the first experiment without any further tuning and showed excellent robust performance.

Nonlinear optimization of robust H/sub /spl infin// controllers for industrial robot manipulators

In this paper, the design of a position tracking control scheme for an industrial robot manipulator is considered. The design is based on the normalized left coprirne factors robust stabilization approach. By coupling this H ∞ synthesis technique to a sequential quadratic programming optimization procedure, a systematic design method for the optimization of the controller's performance is developed. Further, the role of the nominal model, which serves as the basis of the design, is also explored. The control scheme is successfully implemented and tested on a real industrial robot manipulator. The computed controller has worked immediately in the first experiments without any further tuning and shows excellent robust performance superior to that of the existing PID controllers.

http://ieeexplore.ieee.org/iel7/7055173/7081895/07082464.pdf

H. G. Sage

Papers

Robust control of robot manipulators: A survey

Nonlinear optimization of robust H/sub /spl infin// controllers for industrial robot manipulators

Performance optimized H ∞ control of industrial robot manipulators

Canonical Parametrization Of Stable Systems Satisfying a Given Bound On Their H∞ Norm

H∞ Optimal Control for Industrial Robot Manipulators