Motor Current Based Force Control of Simple Cable-Driven Parallel Robots

State of the art cable-driven parallel robots achieve high precision and reliability using a complex setup. The complexity results largely from the integration of force sensors which are omitted in the presented design. Instead, a motor current based approach is proposed to determine the cable forces. Therefore, methods are employed to compensate the cogging torque of the motor and frictional forces along the transmission path from the motor torque to the acting force at the platform. Despite the compensation, it is useful to reduce the overall frictional forces. Therefore, a gearless design scheme with a single pivoting pulley for cable guidance is realized. The proposed approach enables the application of advanced control methods for simple cable-driven robots.