Solving the Forward Kinematic Problem of UnderConstrained Cable Driven Robots for Online Control Purposes

In this paper, a method is proposed which allows computing the position of the end-effector base on neural networks approach by considering external forces applied to the end-effector. As in under-constrained robots kinematics and statics are intrinsically coupled together, and they simultaneously should be considered, the forward kinematic problem of the robot converts to an optimization problem. Solving the optimization problem is time consuming and not suitable for practical purposes. So, in order to solve the forward kinematics problem a SimMechanics model base on the robots geometry and dynamic designed and presented. By means of this method, the forward kinematic problem is solved offline and used online. Moreover, an analysis of workspace is performed which reveals that the solution of the forward kinematic problem of the under-constrained cable robots can be calculated uniquely. By means of neural network method A position control is performed and the proposed method is validated. The comparison of operated and desired path is shown for a helical trajectory. Maximum error in the assumed workspace is 0.4 percent. Finally the proposed method was implemented experimentally and the results confirm the efficiency of the foregoing method.