Cable Driven Robot to Simulate Low Gravity and Its Applications in Underwater Humanoid Robots

[Abstract] This paper addresses the main results obtained during the design and analysis of a cable-driven robot able to simulate the dynamic conditions existing in underwater environment. This work includes the kinematic and dynamic modeling as well as the analysis of the tension of the cables along different trajectories. The low-gravity simulator application is novel in the context of cable-driven robots and it is aimed to be implemented in an underwater humanoid robot. Therefore, this work can be seen as a test case of the complementary research contributions of the group of Robotics and Intelligent Machines at CAR in the recent years.The research leading to these results has received funding from the Spanish Government CICYT project Ref. DPI2014-57220-C2-1-P, DPI2013-49527-EXP, the Universidad Politécnica de Madrid project Ref. AL14-PID-15, and the RoboCity2030-III-CM project (Robótica aplicada a la mejora de la calidad de vida de los ciudadanos. Fase III; S2013/MIT-2748), funded by Programas de Actividades I+D en la Comunidad de Madrid and cofunded by Structural Funds of the EUUniversidad Politécnica de Madrid; AL14-PID-15Comunidad de Madrid; S2013/MIT-2748https://doi.org/10.17979/spudc.978849749808

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

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

A Deployable Cable-Driven Parallel Robot With Large Rotational Capabilities for Laser-Scanning Applications

This paper presents a novel Cable-Driven Parallel Robot dedicated to laser-scanning operations. The proposed device can inspect low-accessibility environments, thanks to a self-deployable end-effector, which can be inserted in a closed container through very small access areas, such as hatches, pipes, etc. The reconfigurable end-effector is suspended and actuated by extendable cables, and is equipped with an optical mirror, which is used to deflect a laser beam produced by a frame-fixed laser distance sensor. Thanks to its large orientation capabilities, the machine can record the position of points belonging to a large portion of the surface to be scanned, primarily by tilting and panning the end-effector. The robot is equipped with a frame-orientation calibration device, which can align the machine frame to earth gravity before operation. The robot capabilities are validated by a prototype, which experimentally reconstruct benchmark surfaces