Experimental results of an impedance-controlled PKM for assembly tasks

The paper presents the experimental results of a three-degree-of-freedom, purely translational parallel kinematics machine, developed by the PMARlab research group of the University of Genova. Thanks to its low-friction components and to the absence of gear-boxes, the robot mechanism is reversible; this feature allows to control the force exerted by the end-effector by regulating the actuator currents, applying an impedance algorithm; therefore the robot can effectively perform tasks that require the control of the interactions with the environment, such as assembly operations, without the additional costs related to the placement of force sensors on the end-effector. The robot performance has been tested in the assembly of deformable components, pursuing the goal of reproducing the time-history of the mating force applied by a human operator, with good results.