Hybrid Position-Force Control of a Cable-Driven Parallel Robot with Experimental Evaluation

Abstract

Abstract. For cable-driven parallel robots elastic cables are used to manipulate a mobile platform in the workspace. In this paper, we present a hybrid position-force control, which allows for applying defined forces on the environment and simultaneous movement along the surface. We propose a synchronous control of the cable forces to ensure the stability of the platform during movement. The performance of the controller is experimentally investigated regarding contact establishment and dynamic behavior during a motion on the cable robot IPAnema 3.

Force-Sensor-Free Implementation of a Hybrid Position–Force Control for Overconstrained Cable-Driven Parallel Robots

“…When the end-effector must apply a specific wrench to an external object, a hybrid position-force control in Cartesian space may be applied. For this goal, the end-effector DOFs are divided according to their method of control, which is either in force or in position [36,37]. The same concept can be used in the joint space to develop a different hybrid position-force control.…”

A Practical Approach for the Hybrid Joint-Space Control of Overconstrained Cable-Driven Parallel Robots

“…A different strategy was proposed as a simple feed-forward alternative to more complex closed-loop controllers [1,2], and it was later called hybrid force-position control in joint space (hybrid joint-space control, in short) [10]. According to this strategy, the robot inputs, namely the joint-space controlled variables, are divided into position-and force-controlled ones, similar to hybrid control techniques in the Cartesian space, where EE controlled variables are similarly divided [7]. In practice, hybrid joint-space control results in several cables equal to the robot degree of redundancy being tension controlled, while the others are length controlled.…”

Force-distribution sensitivity to cable-tension errors in overconstrained cable-driven parallel robots

“…In practice, to ensure feasible cable tensions, a FD is computed and the torque input is corrected using a specific method, such as a feedback linearization controller [11]. When the EE is in contact with the environment, a different strategy is often used [15,16]. The latter is known as hybrid position-force control: the only inputs are the motor angles, but both position and the contact force at the EE are the outputs.…”