Control of cooperative multiple flexible joint robots

The author addresses the problem of controlling multiple flexible joint robots (mFJR) during cooperative manipulation of a rigidly grasped common load (this problem is called the cmFJR problem). The dynamic model of the cmFJR shows that the interaction between the manipulators in the closed chain in the mFJR system is analogous to a single manipulator interacting with a frictionless (algebraic constraint) surface while in motion along the surface. It is assumed that each flexible joint robot is equipped with joint velocity and position sensors and actuator-mounted position and velocity sensors. It is shown that it is not necessary to use force sensors mounted on the robot wrist in order to track a desired load trajectory and an internal force trajectory. The transient response of the position error and the internal force error can be arbitrarily assigned, despite the fact that force sensors are not used