Bilateral Control Based on Disturbance Observer of Delta Robot with Gravity Compensation

Abstract

Recently, delta robots is widely used in many industrial application because the structure of delta robot is close loop chain and have properties of high rigid body and fast movement. However, the moving part of delta robot is arranged in pattern that influenced by gravity and has an impact on control system. In this paper, we proposed force and position control in master-slave configuration while compensate gravity. The control system using disturbance observer (DOB) to estimate sum of action/reaction force and gravity force of master-slave delta robot instead of the force sensors. The external force on travelling plate of delta robot is estimated by disturbance force on upper and computational gravity force from dynamic model. Moreover, the delta robot may various in size due to the conditioning of workspace, therefore the method to control the task space is proposed. The simulation is conduct to verify the control system, compare the position and force of travelling plate with and without gravity compensation.