Synthesis of an Extended Kalman Filter for Cable-Driven Parallel Robots

Cable-driven parallel robots are light-weight parallel robots where cables replace rigid actuators to move an end-effector. As a consequence, they have large workspaces, high-dynamic handlings, ease of reconfigurability and/or low-cost architecture. Knowing the full state variables of the robot model is usually useful for control and monitoring; however, it is often not directly measured and therefore the development of state observers is essential. In this work a general approach to develop a nonlinear state observer based on an Extended Kalman Filter is proposed and validated numerically by referring to a cable-suspended parallel robot. The state observer is based on a system model obtained converting a set of Differential Algebraic Equations into Ordinary Differential Equations through two different methods: the penalty formulation and the Udwadia-Kalaba formulation.