Digital redesign of robot control

Abstract

A control algorithm with nonlinear feedback is effective for the precise motion control of robot manipulators. It is usually designed in continuous-time form, although it is digitally implemented. In this paper, a continuous nonlinear control law for a robot manipulator is redesigned for digital implementation. The digital control law is derived so that the response of the digital control system is close to that of the continuous control system. The amount of computation for the redesigned control algorithm is almost the same as the amount of computation for the original nonlinear control algorithm. The redesign method provides satisfactory stable results even for a fairly large sampling interval. The simulation and experimental results illustrate the effectiveness of the proposed redesign method.

GA-based intelligent digital redesign of fuzzy-model-based controllers

“…is and and is THEN for (8) where is the feedback gain to be digitally redesigned in the th fuzzy subspace. The defuzzified output of the fuzzy-modelbased controller is given by (9) where…”

“…The intelligent digital redesign problem can be stated as follows: Given the continuous-time nonlinear system (1), the continuous-time fuzzy-model-based controller (4) and the sampling time , design a discrete-time fuzzy-model-based controller (8) to minimize the cost function defined by (10) where is the final time of interest, and are the th state variables of the state vectors and , respectively, with a sufficiently large integer , and and are the th state variables of the state vectors and evaluated at , respectively. The intersampling behavior of the analogously controlled system can also be considered by the objective function (10).…”

“…Thanks to the extensive research works of various kinds of digital redesign techniques by Shieh et al [1], [3], [5], [6], the digital redesign technique for linear sys-tems become attractive for the practical implementation of digital controllers. However, there are relatively less research works on the digital redesign of nonlinear systems [8]- [10] since it is very difficult, if not impossible, to derive an analytical solution of the digital redesign of complex nonlinear systems. Yokoyama et al [8] applied a digital redesign technique for the motion control of a nonlinear robot manipulator system by using the linear approximation technique.…”

“…However, there are relatively less research works on the digital redesign of nonlinear systems [8]- [10] since it is very difficult, if not impossible, to derive an analytical solution of the digital redesign of complex nonlinear systems. Yokoyama et al [8] applied a digital redesign technique for the motion control of a nonlinear robot manipulator system by using the linear approximation technique. Xu et al [9] successfully established a digitally redesigned controller for the chaotic Chua's circuit.…”

A Novel Tracker for a Class of Sampled-data Nonlinear Systems

“…Taking advantage of digital technology, various digital control techniques have been developed. While another efficient approach is the so-called digital redesign (Kuo, 1980;Yokoyama et al, 1989;Joo et al, 1999;Shieh et al, 1999Shieh et al, , 2000Guo et al, 2000Guo et al, , 2001Chang et al, 2002), to convert the well-designed analog controller into the equivalent digital one, maintaining the properties of the original analog control system in the sense of state-matching, by which the benefits of both the analog controller and the advanced digital technology can be achieved. Recently, Shieh and his collaborators have investigated in digital redesign focusing on the state-feedback controller Joo et al, 1999;Guo et al, 2000;Shieh et al, 2000;Lee et al, 2003).…”