An impedance-controlled parallel robot for high-speed assembly of white goods

Purpose – Aims to discuss how impedance-controlled parallel robots can effectively perform industrial assembly tasks. Design/methodology/approach – A new purely translational parallel robot has been designed to fulfil the requirements of industrial assembly tasks. The kinematic and dynamic models of the robot have been obtained in analytic form. A full-scale prototype has been realized within the Italian research programme PRIDE (Parallel Robots Interacting with Dynamic Environments). An impedance control algorithm based on the kinematic and dynamic models has been implemented on the control unit of the PRIDE prototype. The effectiveness of the impedance-controlled PKM has been evaluated performing the assembly of white goods components. Findings – The test results show that the combined use of impedance control and dynamic compensation applied to parallel kinematics machines allows to reduce remarkably the operational time compared to the currently used position-controlled industrial robots. Research limitations/implications – The experimental tests on the PRIDE prototype show the overall industrial feasibility of impedance-controlled parallel kinematics machines. Practical implications – The introduction of impedance-controlled PKMs may improve, with a relatively low cost, the level of automation of several production plants in which delicate operations requiring force control are still executed manually. Originality/value – While there is a large number of existing position-controlled PKMs, the experimental research about force-controlled or impedance-controlled PKMs is not widespread.