Design of reduced DOF parallel cable-based robots (original) (raw)
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In this paper, we study the design and workspace of a 6-6 cable-suspended parallel robot. The workspace volume is characterized as the set of points where the centroid of the moving platform can reach with tensions in all suspension cables at a constant orientation. This paper attempts to tackle some aspects of optimal design of a 6DOF cable robot by addressing the variations of the workspace volume and the accuracy of the robot using different geometric configurations, different sizes and orientations of the moving platform. The global condition index is used as a performance index of a robot with respect to the force and velocity transmission over the whole workspace. The results are used for design analysis of the cable-robot for a specific motion of the moving platform.
Journal of Technical Education Science
One of the main concerns in controlling the cable-driven parallel robot (CDPR) mechanism is dealing with the distribution of tension on each cable, which is critical to the operation of the entire cable system. It can be said that adjusting the cable tension will determine the power consumption of the motors and the stiffness of the structure. Therefore, the problem that needs to be solved is how to handle the cable tension when the end-effector moves throughout the entire workspace. The tension of each cable needs to be adjusted properly to ensure it remains the same. Moment and force act in a static state, keeping the kinematic position of the end moving platform from being deflected and the main purpose is to ensure that the robot achieves a rigid state and eliminates vibration when moving. Because of that essential demand, this article will refer to the Quadratic programming algorithm to solve the problem of tension distribution for the Planar Cable-Driven Parallel Robot consist...
Design and workspace analysis of a 6–6 cable-suspended parallel robot
Mechanism and Machine Theory, 2004
In this paper, we study the design and workspace of a 6-6 cable-suspended parallel robot. The workspace volume is characterized as the set of points where the centroid of the MP (MP) can reach with tensions in all suspension cables at a constant orientation. This paper attempts to tackle some aspects of optimal design of a 6DOF cable robot by addressing the variations of the workspace volume and the accuracy of the robot using different geometric configurations, different sizes and orientations of the MP. The global condition index is used as a performance index of a robot with respect to the force and velocity transmission over the whole workspace. The results are used for design analysis of the cable-robot for a specific motion of the MP. 0-7803-7860-1/03/$17.00
Design and implementation of a multi-degrees-of-freedom cable-driven parallel robot with gripper
International Journal of Advanced Robotic Systems, 2018
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 struct...
Four-cable-driven parallel robot
This paper presents design and kinematic analysis for a cable-driven parallel robotic (CDPR) manipulator with four cables, The CDPR manipulator produces a planar motion including two translational and one rotational degrees of freedom. To move the end-effector of CDPR, its kinematic structure is analyzed and the inverse kinematics is formulated in the closed-form solution. The experimental tests using an implemented prototype have shown the feasibility of the system design and its operation.
Mechanics Based Design of Structures and Machines, 2017
This study investigates the three-dimensional static and dynamic stiffness analyses of the cable driven parallel robot by considering cable mass, elasticity and mass of end-effector. According to these models, optimization of cable tensions and cable lengths using fminimax solver is carried out to determine the static stiffness. Static and dynamic stiffness of the cables are obtained with simulations. Results show that analyses in three-dimension are very important to measure the actual performance of the cable driven parallel robot. This demonstrates potential for general applicability and motion of the cable driven parallel robot.
Geometrico-Static Analysis of Under-Constrained Cable-Driven Parallel Robots
Advances in Robot Kinematics: Motion in Man and Machine, Springer.
This paper studies the kinematics and statics of cable-driven parallel robots with less than six cables, in crane configuration. A geometrico-static model is provided, together with a general procedure aimed at effectively solving, in analytical form, the inverse and direct position problems. The stability of equilibrium is assessed within the framework of a constrained optimization problem, for which a purely algebraic formulation is provided. A spatial robot with three cables is studied as an application example.
2013 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2013
This paper addresses the simplification of cable model in static analysis of large-dimension cable-driven parallel robots (CDPR). An approach to derive a simplified hefty cable model is presented. The approach provides an insight into the limitation of such a simplification. The resulting cable tension computation is then used to solve the inverse kinematic problem of CDPR. A new expression of cable length taking into account both the non-negligible cable mass and elasticity is also introduced. Finally, simulations and experiments on a large CDPR prototype are provided. The results show that taking into account both cable mass and elasticity improves the robot accuracy.
Optimal design of cable-driven parallel robots for large industrial structures
2014 IEEE International Conference on Robotics and Automation (ICRA), 2014
This paper presents the preliminary studies dedicated to the design of cable-driven parallel robots (CDPRs) for industrial purposes. The goal is to transport the proper tools around a jacket, an offshore structure supporting a wind turbine, in order to perform painting and sandblasting tasks. In this paper, a simplified case study consisting of a structure composed of four tubes is investigated. A fully constrained CDPR and a suspended CDPR are studied. The design problems of the CDPRs at hand are formulated as optimization problems. They aim at determining the locations of the base anchor points of the cables that minimize the size of the CDPR, while satisfying a set of constraints. Those constraints guarantee that the moving platform can support the external wrenches and that there is no interference between the cables and between the cables and the environment, all along the path to be followed by the moving platform.
Design and Control of a Suspended Cable-Driven Parallel Robot with Four Cables
—This paper presents the state of the art of design and control of a new suspended under-constrained cable-driven parallel robot with four cables. In order to improve the estimation of the cable lengths, an auxiliary roller screw mechanism is utilized to move the winch linearly for proper cable coiling on one layer. Also, in order to compute the configuration of the robot in real-time, a gyro sensor is installed on the end-effector. The collected data from the gyro sensor is used to make equivalent the solution of the direct geometric-static problem to the solution of linear system of equations. The foregoing reduced system can be readily solved and leads to the position of the end-effector in real-time which is a definite asset in control. Moreover, kinematic problem of the cable-driven parallel robot is provided and a new approach for solving the forward kinematic problem is proposed.