Kinematic Modeling of Samen SpaceCam Robot with Deflection of Flexible Cables

In some of cable-driven parallel robots the end-effector position is determined by the length of cables. In fact, the length of cables is estimated by the motor''s encoder count and the end-effector position is obtained by using the direct kinematics equations. The weight and flexibility of cable lead to deflection in the cable. Therefore, the deflection of the cables leads to error in the end-effector position. Hence, the length of cables without deflection must be determined for direct kinematic equations of the robot. In this paper, first of all inverse and direct kinematics equations of Samen SpaceCam cable-driven robot are derived. Next, length of the cables without deflection is calculated for the direct kinematic of the robot. Finally, we compare the end-effector positions obtained from the actual cable length and without deflection one together.