A robust anti-windup control design for electrically driven robots — Theory and experiment

Abstract

A Robust Anti-Windup Control (RAWC) method is proposed for n-Degree-of-Freedom (DOF) electrically driven robots considering the actuator voltage saturation. The actuator's saturation is fairly modeled by a smooth nonlinear function and the control design task is developed to avoid windup besides being robust against both model uncertainties and external disturbances. As a major point, the paper also takes into consideration the fact that windup phenomenon can be caused by some strong disturbances. As a result, being robust to external disturbances promises safer situation against windup. The proposed controller needs no saturation output feedback and torque's measurement for control implementation. The analytical studies as well as the experimental results produced using MATLAB/SIMULINK External Mode Control on a 2-DOF robot manipulator driven by geared Permanent magnet DC motors prove the superiority of the proposed approach.

Robust Optimal Adaptive Trajectory Tracking Control of Quadrotor Helicopter

“…Sometimes, the best tracking and regulation performance are achievable by means of large control input magnitude which may exceed the actuators' bounds. Disregard of actuator limits probably brings about system's collapse; in addition, undesired transient response and even damaging the actuators can be the other effects (Izadbakhsh et al (2011)). In Kendoul et al (2007), global asymptotic stability of quadrotor and boundedness of control inputs are guaranteed via nested-saturation based nonlinear controller.…”

Single-loop versus multi-loop control strategies for electrically driven robots with elastic joint

“…Then, according to Fig. 1, we have This result, together with (5), (11) and (17), gives (17) e(t) + k p e(t) =̃ T (x) + dzn(u(t), u ) + (x) The last inequality will be negative definite if As a result, the link position-tracking error is bounded. Since e is bounded, boundedness of q can be obtained, whereas q d is bounded.…”

Robust adaptive control of robot manipulators using Bernstein polynomials as universal approximator

“…For practical situations, the actuator input voltages are subjected to some constraints, called motor saturation limits. This occurs usually between output of the controller and the PWM module . Following the same notation as in Reference , for the development of the controller in this article, we assume that the relation between the actual actuator's input ( v ( t ) ∈ ℜ n ) and the control signal produced by the controller ( u ( t ) ∈ ℜ n ) is given by where h ( u ( t )) ∈ ℜ n is a continuous nonlinear function representing the saturation nonlinearity or its approximation.…”

“…Following the same notation as in Reference , for the development of the controller in this article, we assume that the relation between the actual actuator's input ( v ( t ) ∈ ℜ n ) and the control signal produced by the controller ( u ( t ) ∈ ℜ n ) is given by where h ( u ( t )) ∈ ℜ n is a continuous nonlinear function representing the saturation nonlinearity or its approximation. As shown in Reference the nonimplemented control signal of the actuators can be expressed as …”