A novel parallel robot for current microassembly applications

Abstract Purpose – Aims to discuss how a Cartesian parallel robot with flexure revolute joints can effectively perform miniaturized assembly tasks. Design/methodology/approach – The results of the test and validation phase of a Cartesian parallel robot designed for miniaturized assembly are shown. The workspace volume is a cube with 30mm side and the target accuracy is 1mm. Each of the three robot legs has a prismatic-planar architecture, with a cog-free linear motor and a planar joint realized using ten superelastic flexure revolute joints. Flexure joints are adopted in order to avoid stick-slip phenomena and reach high positioning accuracy; their patented construction is relatively low-cost and allows a quick replacement in case of fatigue failure. Findings – The tests on the prototype are very encouraging: the measured positioning accuracy of the linear motors is ^0.5mm; on the other hand, the effects of unwanted rotations of flexure joints and hysteresis of the superelastic material are not negligible and must be properly compensated for in order to fully exploit the potential performance of the machine. Practical implications – The introduction of this robotic architecture can fulfil the needs of a wide range of industrial miniaturized assembly applications, thanks to its accurate positioning in a relatively large workspace. The cost of the machine is low thanks to its extreme modularity. Originality/value – The combination of Cartesian parallel kinematics, cog-free linear motors and superelastic flexure revolute joints allows one to obtain very good positioning performance.