Experiments in Control of a Flexible-Link Robotic Manipulator With Unknown Payload Dynamics: An Adaptive Approach

Abstract

This article presents technology that extends the concept of end-point control of a flexible-link robot arm to handle payloads with unknown internal dynamics. The approach is based on merging high-performance control with an innovative identification algorithm in a self-tuning regulator framework. Payload dynamics are identified in real time using recently developed subspace fitting techniques. Sufficient excitation issues are addressed. End-point feedback controllers are formulated using frequency-weighted linear quadratic gaussian design methods.Experimental results demonstrating precision control of a very flexible single-link robot arm with unknown dynamic payloads are presented.

Engineering Test Satellite VII Flight Experiments for Space Robot Dynamics and Control: Theories on Laboratory Test Beds Ten Years Ago, Now in Orbit

“…Such test beds have been used in the hardware verification of the Space Shuttle Remote Manipulator System (SRMS; Wargner-Bertak, Middleton, and Hunter 1980), in the Space Station Remote Manipulator System (SSRMS), and in the other manipulator systems that will be mounted on the International Space Station (Morimoto et al 2002). Among academic laboratories, Stanford University was one of the first to have performed an extensive study on a flexible manipulator and a free-flying/floating space robot using an air-cushion test bed (Alexander and Cannon 1987;Koningstein, Ullman, and Cannon 1989;Alder and Rock 1994). Tokyo Institute of Technology (TIT) has developed the same type of test bed.…”

Evaluation of Six Different Sensor Fusion Methods for an Industrial Robot using Experimental Data

“…One commonly used observer is the linear Kalman filter (KF) or the extended Kalman filter (EKF), used for nonlinear systems. A KF is used for a single-axis robot arm in [5] and [6]. EKFs are used in [7], and also in [8], where a two-axis robot, with tool position and joint speed measurements, are used.…”

Extended Kalman Filtering Applied to a Two-Axis Robotic Arm with Flexible Links

“…Hollars and Cannon (1990) used a constant-gain version of an extended Kalman filter (EKF) to estimate, for use by a state feedback control law, the state of a planar two-link robot arm with rigid links and flexibility in its joints. Alder and Rock (1994) used a linear Kalman filter and a state feedback control law in conjunction with an adaptive control algorithm to control the end-effector position of a planar one-link flexible robot arm with unknown payload dynamics. The same authors (Alder and Rock 1996) used a linear Kalman filter to estimate the state of a planar one-link flexible robot arm in the presence of permanent link deformations.…”