Many university and government laboratories have constructed robot hands capable of grasping and manipulating objects. But teaching

Question:

Many university and government laboratories have constructed robot hands capable of grasping and manipulating objects. But teaching the artificial devices to perform even simple tasks required formidable computer programming. Now, however, the Dexterous Hand Master (DHM) can be worn over a human hand to record the side-to-side and bending motions of finger joints. Each joint is fitted with a sensor that changes its signal depending on position. The signals from all the sensors are translated into computer data and used to operate robot hands [1].
The DHM is shown in parts (a) and (b) of Figure DP12.3. The joint angle control system is shown in part (c). The normal value of Km is 1.0. The goal is to design a PID controller so that the steady-state error for a ramp input is zero. Also, the settling time (with a 2% criterion) must be less than 3 seconds for the ramp input. We want the controller to be

(a) Select KD and obtain the ramp response. Plot the root locus as KD varies, (b) If Km changes to one-half of its normal value and Gc(s) remains as designed in part (a), obtain the ramp response of the system. Compare the results of parts (a) and (b) and discuss the robustness of the system.