Hybrid position force coordination for dual-arm manipulation of flexible materials

The problem of coordinating two arms for the manipulation of flexible materials is studied through the bending of a flexible beam. The solution proposed an this paper is based on a hybrid position/force approach. The choice of controlled variables in each direction is determined by minimum-effort optimality criteria. The bending effort is defined as the overall bending moment and force applied by the grippers. The control of forces exploits the material's elasticity, which is an impedance for the manipulators. The force controller then behaves as an admittance, in the form of an accommodation (inverse damping) law. Experimental results show the efficacy of the approach in achieving task requirements.