[13] In Fig. 3.31, the location of the tool, T, is not accurately known. Using force control, the robot feels around with the tool tip until it inserts it into the socket (or Goal) at location T. Once in this "calibration" configuration (in which {G} and {T) are coincident), the position of the robot, is figured out by reading the joint angle sensors and computing the kinematics. Assuming T and T are known, give the transform equation to compute the unknown tool frame, T.