Question A1. Consider a robot arm with three degrees of freedom shown in Figure QA1. (a) Assign the co-ordinate frames based on the Denavit-Hartenberg (D-H) representations. (b) Fill out the D-H parameter table. (c) Write all transformation A matrices of the joints. [20%] [30%] [30%] (d) Write the transformation matrix from the wrist of the robot to the base of the "T matrix in terms of the A matrices. xu Zu 12 13 d2 li d Yu ZH XH YH Figure QA1: The robot. [20%]