Isotropic compliance in RRP planar manipulators

In the present paper, the isotropic compliance property is investigated, specifically focusing on RRP plane manipulators. The property is achieved by means of active stiffness regulation, considering three different control strategies, dependent on the joint exerting the control action. For each case, the analytical solutions and the corresponding workspace subsets are presented. To compare the three methods, the active and overall stiffness coefficients are evaluated in the postures defining the isotropic compliance subsets. The feasibility of the methods is also evaluated, considering the passive and active stiffness coefficients.