Design and implementation of a multi-degrees-of-freedom cable-driven parallel robot with gripper

Abstract

Cable-driven parallel robots comprise driven actuators that allow controlled cables to act in parallel on an end-effector. Such a robotic system has a potentially large reachable workspace, large load capacity, high payload-to-weight ratio, high reconfigurability, and low inertia, relative to rigid link serial and parallel robots. In this work, a multi-degrees-of-freedom cable-suspended robot that can carry out pick-and-place tasks in large workspaces with heavy loads is designed. The proposed cable-driven parallel robot is composed of a rigid frame and an end-effector that is suspended from eight cables—four upper cables and four lower cables. The lengths of the cables are computed from the given positions of the suspended end-effector using a kinematic model. However, most multi-cable-driven robots suffer from interference among the cables, requiring a complex control methodology to find a target goal. Owing to this issue with cable-driven parallel robots, the whole control structure decomposes positioning control missions and allocates them into upper level and lower level. The upper level control is responsible for tracking the suspended end-effector to the target region. The lower level control makes fine positional modifications. Experimental results reveal that the hybrid control mode notably improves positioning performance. The wide variety of issues that are considered in this work apply to aerostats, towing cranes, locomotion interfaces, and large-scale manufacturing that require cable-driven parallel robots.

Motion control of a cable-suspended robot using image recognition with coordinate transformation

“…The system configuration, shown in Figure 2, is similar but not totally the same one presented elsewhere. 14 The weight of the suspended platform, which included gripper, is around 1.14 kg. The position of the suspended platform is controlled by AC servomotors that can retract or extend the cables to which it is attached.…”

“…The derivation procedure for kinematic calculation can be applied to geometric concept, as indicated in Figure 3. The detailed kinematic derivation is similar to that of Lin et al 14 The distances from a fixed point on the main frame to the specific point on the suspended platform are given by l i ( i = 1,…,8). The lengths of the upper cables are denoted as l i ( i =1, 2, 3, 4) and lengths of the lower cables are specified as l i ( i = 5, 6, 7, 8), respectively.…”

“…Currently, various styles of crane constructions are extensively applied in material handling for various manufacturing purposes. 14–17 Nevertheless, several kinds of payloads have to be loaded and unloaded, such as satellites, aircrafts, and other eccentric payloads. This affects the lateral and inclination forces while loading and unloading that can lead to payload devastation, impairment, or spin.…”

“…17 Hence, in order to resolve those concerns, some control schemes to carry out material-handling tasks have been proposed and demonstrated in previous studies. 14–17…”

Design Optimization of Redundantly Actuated Cable-Driven Parallel Robots for Automated Warehouse System

“…By driving the mobile platform through cables, all the drive units, including motors and gear reducers, can be located on the base structure to decrease the mass and inertia. At present, many CDPR prototypes have been designed to perform various tasks, such as manufacturing operations for large-scale material [3], high-speed photography in stadiums [4], giant radio telescopes [5], and handling operations for heavy payloads in huge workspaces [6], among others [7]- [9]. Hassan and Khajepour [10] proposed a symmetric CDPR of a large-workspace manipulator for automated warehouse system, and the mobile platform parameters are optimized to enhanced the manipulator stiffness.…”