A new pose measuring system based on a spatial four bar linkage with RSSR chain

An innovative low cost device for the measuring of the pose, 3 translation and 3 rotations, of a body was presented. The proposed measuring system consists in a spatial four bar mechanism with a symmetrical (RSSR) kinematic structure. The first link of the chain is connected to a fixed reference system and the last one to the moving body to be tracked. The estimation procedure in analytical form was developed and the uncertainty of the estimation caused by the limited repeatability of the used sensors was derived. The uncertainty of the pose estimation was also investigated and a numerical example of the achievable measuring range and uncertainty was also illustrated. It was found that by using the proposed system all the six coördinates of the pose of the mobile frame can be measured simultaneously.