Reconfigurable fully constrained cable-driven parallel mechanism for avoiding collision between cables with human

Abstract

Productivity can be increased by manipulators tracking the desired trajectory with some constraints. Humans as moving obstacles in a shared workspace are one of the most challenging problems for cable-driven parallel mechanisms (CDPMs) that are considered in this research. One of the essential primary issues in CDPM is collision avoidance among cables and humans in the shared workspace. This paper presents a model and simulation of a reconfigurable, fully constrained CDPM enabling detection and avoidance of cable–human collision. In this method, unlike conventional CDPMs where the attachment points are fixed, the attachment points on the rails can be moved (up and down on their rails), and then the geometric configuration is adapted. Karush–Kuhn–Tucker method is proposed, which focuses on estimating the shortest distance among moving obstacles (human limbs) and all cables. When cable and limbs are close to colliding, the new idea of reconfiguration is presented by moving the cable’s attachment point on the rail to increase the distance between the cables and human limbs while they are both moving. Also, the trajectory of the end effector remains unchanged. Some simulation results of reconfiguration theory as a new approach are shown for the eight-cable-driven parallel manipulator, including the workspace boundary variation. The proposed method could find a collision-free predefined path, according to the simulation results.

Motion Planning for a Cable-Driven Lower Limb Rehabilitation Robot with Movable Distal Anchor Points

“…But this method has some limitations, it needs to plan the cable direction in advance, and the movement of some distal anchor points must be spatial. For the M-CDPRs obstacle avoidance research, Youssef [22,23] studied the fully constrained M-CDPR, its distal anchor points change their positions according to the distance between cables or between cable and human in real time to avoid collision. An [24] proposed a novel M-CDPR and studied its collision detection method and the obstacle avoidance algorithm when multiple moving or/and static obstacles exist.…”

Nonlinear optimal control for a 4-DOF SCARA robotic manipulator

“…Potential application areas for the article's developments, always related to industrial robotics, are described in refs. [32][33][34][35].…”