Time Optimal Trajectory Tracking of Redundant Planar Cable-Suspended Robots Considering Both Tension and Velocity Constraints

Abstract

In this paper, time optimal trajectory tracking of redundant planar cable-suspended robots is investigated. The equations of motion of these cable robots are obtained as a system of second order differential equation in terms of path parameter s using the specified path. Besides, the bounds on the cable tensions and cable velocities are transformed into the bounds on the acceleration and velocity along the path. Assuming bang-bang control, the switching points in ṡ2−s plane are obtained. Then the cable tensions are found in terms of path parameter and, subsequently, versus time. The proposed approach is validated and the effect of the number of superfluous cables on the value of minimum time is studied. The next notable challenges include time optimal path planning of cable-suspended robots. By developing a hybrid genetic algorithm and bang-bang control approach, the minimum motion time from initial state to final one and also the corresponding path can be found. The optimum path is the one that minimizes traveling time from initial state to final one, while not exceeding the cable tensions and cable velocities limits, without collision with any obstacles.

Dynamic trajectory planning study of planar two-dof redundantly actuated cable-suspended parallel robots

“…In other words, this robot is a planar redundantly actuated cable-suspended robot. In previous literature [18], redundantly actuated cables are considered to decrease motion time and to reduce the loads among cables for a specific trajectory. In [16,17], dynamic workspace and dynamical parametric features for straight line and circular periodic Cartesian trajectories are developed for a cable-suspended two-dof robot.…”

“…Compared with two-cable planar robots, redundantly actuated cable robots bring more challenges for dynamic trajectory planning but may also offer more potential. A similar analysis of redundantly actuated planar cable-suspended robots is also presented in [18], but which focuses on the trajectory tracking with optimal time based on tension and velocity constraints.…”

Dynamic trajectory planning of planar two-dof redundantly actuated cable-suspended parallel robots

“…Compared with two-cable planar robots, redundantly actuated cable robots bring more challenges for dynamic trajectory planning but may also offer more potential. A similar analysis of redundantly actuated planar cable-suspended robots is presented in [15], but which focuses on the trajectory tracking with optimal time based on tension and velocity constraints.…”

Iterative Learning Tracking Control of a Hybrid-Driven Based Three-Cable Parallel Manipulator

“…Workspace and stiffness analysis of cable-driven manipulators considering cable mass has been investigated by Arsenault [9]. Different aspects like time optimal trajectory tracking [10], workspace [11], and bounded cable tensions [12] were also investigated extensively. Notash and Kamalzadeh [13] investigated the dynamics of wire-actuated parallel manipulators with a constraining linkage by Lagrangian method.…”