Collision-Free Workspace Design Optimisation of the 3-DOF Gantry-Tau Parallel Kinematic Machine

One of the main advantages of the Gantry-Tau machine is a large accessible workspace/footprint ratio compared to many other parallel machines. The Gantry-Tau improves this ratio by allowing a change of assembly mode without internal link collisions or collisions between the links and the moving TCP platform. This paper introduces an optimisation scheme based on the geometric approach for the workspace area and the functional dependencies of the elements of the static matrix and the minimum distance between two links to define the collisions between robot’s links. The results show that by careful design of the manipulated platform, a collision free workspace can be archived. Kinematic design obtained by optimisation according to this paper gives a workspace/footprint ratio of more than 3.5. In addition, a workspace optimisation method is presented where the parameters are the support frame lengths and the robot’s arm lengths.