A cascade structure for robust control design

Abstract

Absfraet-In the context of robust control theory and applications, the well-known variable structure approach and the so-called binary control approach offer both interesting properties and disadvantages. In this note, the idea of combining the two techniques in order to define a cascade structure exploiting the desirable features of both approaches is discussed, and its natural applicability to the control of a nonlinear electrical actuator is shown by a simulation case.

Experimental comparison of decentralized controllers for industrial robots

“…An interesting approach, which seems particularly appropriate for application in mechanical systems, is the recently developed discontinuous integral control, both in the continuous and discrete version. [12][13][14][15][16] The aim of this kind of control is to reduce the chattering introduced by the characteristic switching term of the controller, by adding an integrator with a nonlinear switching input whose purpose is to track the unknown disturbances. In this way, the switching term has to compensate only the difference between the real disturbances and its estimations, so that its effect can be significantly reduced.…”

“…These controllers are the PID-based ones where the control scheme basically consists of an inner velocity loop and an outer position loop, a nonlinear three term controller proposed by Tarokh 11 and the discontinuous integral control (both in the continuous and discretised version), which is a kind of variable structure sliding mode controller, which has been recently devised. [12][13][14][15][16] The paper is organized as follows: In Section 2 the adopted controllers are described. In Section 3 the experimental setup is presented.…”