Direct compliance control for serial link arm (1st report, Basic concept and decoupling condition)

Force (moment) vector and displacement (displacement angle) vector at the end-effector of robot manipulator are connected through a compliance matrix which can be directly specified by each joint compliance. On the basis of this consideration, Direct Compliance Control (DCC) is proposed and developed for a serial link arm. A framework of the analysis is described for a generalized serial link arm model having n(n+1)/2 compliance components (n: rank of the compliance matrix), and several features of DCC are made clear in comparison with the conventional compliance control scheme. A serial link arm in a horizontal plane is slected as an example of precise model analysis, and the decoupling condition of the compliance matrix is also presented. In order to check the validity of the anlaysis and the decoupling condition, computer simulations and some experiments are performed for several arm attitudes.