Adaptive Gain Control for a Two-Axis, H-Frame-Type, Positioning System

Abstract

XY gantry systems play an important role in many applications in diverse industries, where they are used to position a part or tool along the xy plane within the working area of the system. The increased demand for enhanced performance and low cost of XY gantry systems has driven research to develop alternative structural designs and improve their capabilities. A two-axis, parallel H-frame XY positioning system (H-Bot) is of increasing interest as a candidate for development due to its low number of moving parts, lightweight, low cost and speed of the system. However, the system has an uncertainty of cart or end-effector position when moving at high speed because of the friction and flexibility of the elastic timing belt. The H-bot developed here using an adaptive gain control showed a good repeatability and improved accuracy, reducing the root mean square error between the desired and the actual trajectory of 32.7% and 53.2% on the x-axis and y-axis, respectively, for drawing a 80 mm diameter circle in 36 seconds.