A New Approach to Control Single-Link Flexible Arms. Part 2. Control of the Tip Position in the Presence of Joint Friction
Abstract
This report presents a new way to control the tip position of single link flexible arms when friction is present in the joint. In order to minimize the influence of the nonlinear components of this friction, the control scheme is composed of two nexted loops: an inner loop that controls the motor position, and an outer loop that controls the tip position. It is demonstrated that proper design of the inner loop of this control scheme eliminates the effects of friction in controlling the tip position, and may significantly simplify the design of the tip position controller. Three control schemes are proposed for the outer loop. All of them are based on an hybrid feedforward-feedback control scheme. The first and second schemes use only tip position feedback while the third one uses sensing of positions at several points of the beam. Performances of the three schemes are compared under the following disturbances: a) motor position perturbations, b) unmodelled dynamics, and c) changes in the payload. Experimental results are presented for the two arms described in the Part I; the three tip position control schemes are compared in both arms; and finally, conclusions are drawn.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1989
- Accession Number
- ADA213365
Entities
People
- H. B. Brown Jr.
- Kuldip S. Rattan
- Vicente Feliu
Organizations
- Carnegie Mellon University