Nonlinear suboptimal SDRE controller for cooperative manipulators to increase dynamic load carrying capacity

Abstract

In this paper, the application of state-dependent Riccati equation (SDRE) controller in the field of cooperative manipulators is introduced. The ultimate goal is to increase dynamic load carrying capacity (DLCC) by means of cooperation between robots. Carrying the load with two arms creates constraint in predefined trajectory and complexity for the control problem. The rate of distribution of load between the arms is another subject to be addressed. Optimal load distribution method is selected to solve both: handling the constraint by providing an answer for Lagrange multipliers; and putting each arm under pressure at a desired rate. The brought up points and formulation of SDRE control in cooperative robotics are studied in this paper. Two planar connected arms are simulated to carry a load in a circular path and compared with two separated arms in the same path to show the capability of the proposed controller and enhancement of precision by cooperation. The results revealed success in reducing the error.