Towards a new Delta robot: an inverted Delta
In the way of developing fast parallel robots, the following work proposes a development of a new delta robot. This robot is a 3 d.o.f. parallel robot based on a Delta-like kinematics [Clavel 88, 92]. It is actually an inverted Delta in which the parallel bars are inverted towards the basis. There are two principal advantages of this structure. The first is that there is less links between the actuators and the support basis. The second concerns the fact that end- effector naturally moves without changing the direction of the motors. This last characteristic leads to a fastest structure. This paper is organized as follows: At first, we will present the previous version of the micro-delta [Rey 94] and the actuator trajectories when carrying out a typical pick and place operations. The second part concerns the proposition of this new kinematics (called inverted delta), its optimization, simulation, design and the mechanics. A comparison between the actuator’s trajectories will be shown to stress on the improvements on the fastness of the structure. Finally, the motion control and performances are shown to prove the efficiency of such structure. The experimental position control is presented when using a simplified feed forward controller that seems to be quit sufficient for the desired performances (around 0.1mm at the end effector). This structure has been actually developed for the pick and place operations in the market where there is a need of fast operations relative to small workspace.