Stable force controller design based on frequency response identification

Abstract

This paper proposes a method of stable force controller design for robotic manipulators based on frequency response identification. The force controller described here falls into the hybrid controller category. Force control loops are added to a popular position controller, enabling position control loops and force control loops to be designed independently. The proposed method does not require a detailed model of manipulator and environment dynamics. It is, therefore, robust enough for unmodeled dynamics, and easily analyzes stability in the high frequency region using the phase and gain margin method. The frequency response is identified by an accurate method called multi-decimation (MD), using motor input and contact-force output data. The MD method was previously developed by the author. The force control parameters (i.e. PID feedback parameters) are calculated by a stable design method called partial-modelmatching (PMM), using the identified frequency response. The effectiveness of the proposed design method is demonstrated, through some experimental results, including a tracing task along a stiff environment, carried out using a planar two-link manipulator with harmonic drive gears.

Observer-Based Robust Adaptive Tracking for Uncertain Robot Manipulators with External Force Disturbance Rejection

“…Zongli Lin [112], he discussed the problem related to robust semi-global or practical stabilization problem for Multi-Input and Multi-Output (MIMO) minimum phase linearizable systems, as a control he used output feedback along with squaring-up design [113]. Juhoon Back and Hyungbo Shim [114], used Linear Disturbance Observer (LDO) technique along with output-feedback controller to compensate the effect of disturbances in uncertain nonlinear system for example robot manipulator and this techniques was expected to be implemented in practical applications for increasing the performance of the closed loop system.…”

Comparison of Contact Force Control Strategies on Different Robot Arm Types

“…This control type applied to dual-arm robot manipulators that interact each other [34,35] and to robust control of industrial robots [36], for redundant manipulators extended hybrid position/force control developed [9,12,44]. [37] Studied on the stable force controller design based on frequency response identification.…”