Vision guided multi-probe assembly of 3D microstructures

This paper describes the operator assisted automated assembly of a 3-legged spatial platform by using a vision guided multi-probe assembly process. This is the first step towards the ultimate goal of building a microscale active spatial platform. Two issues are highlighted in this paper: contact management and vision feedback. Using multiple probes for part grasping and manipulation has the advantage of robustness and versatility as compared to micro-grippers. However, the contacts between the probes and the part need to be carefully managed to ensure a grasp that is stable for part pick-up and yet manipulable to allow part motion in a controlled fashion. By using vision guidance, the probes can be coordinated to grasp the parts and lift them off the die securely and reliably. We show that the contacts act as point contacts with friction, so when a part is pressed against a stationary probe, the part rotates about the axis between the contacts, changing its orientation so it may be inserted into a slot in the substrate. We have demonstrated that the three legs can be assembled in a fully automated fashion via multiple-camera vision feedback. The platform is at present assembled via tele-operation. The assembled microstructure measures 450 µm×600 µm. We are now working on the full automation of the assembly onto a substrate populated with MEMS actuators.