Kinematics and Stiffness Modeling of a 4-DOF Parallel Robot for Schönflies Motion Generation

2014 ◽  
Author(s):  
Shaoping Bai ◽  
Lasse Køgs Andersen ◽  
Carsten Rebbe Mølgaard
Keyword(s):  
Dynamic Performance ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Motion Generation ◽  
Stiffness Modeling ◽  
Pick And Place ◽  
Fea Simulation ◽  
Schönflies Motion ◽  
Pick And Place Operation ◽  
Good Agreement

This work deals with the design of parallel robots for the generation of pick-and-place operation, or Schönflies motion. The aim is to develop a robot with workspace optimized for fast pick-and-place operations, namely, a robot with a superellipsoidal reachable volume, which suits best for the pick-and-place operations on conveyers, where robots’ working areas are nearly rectangular. In this paper, the kinematics and stiffness modeling of the new robot are presented. A method of stiffness modeling by means of Castigliano’s Theorem is developed. Using the new method, the stiffness of the robot is analyzed. The results are compared with FEA simulation, which shows a good agreement between the results. The method is finally applied to the engineering design of the new robot for enhanced static and dynamic performance.

Dynamic Analysis of a Parallel Pick-and-Place Robot With Flexible Links

2008 ◽  
Author(s):  
Haihong Li ◽  
Zhiyong Yang
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Lithium Ion ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Modeling And Analysis ◽  
Flexible Links ◽  
Pick And Place ◽  
Floating Frame ◽  
Pick And Place Operation

The dynamic modeling and analysis of a 2-DOF translational parallel robot for high-speed pick-and-place operation was presented. Considering the flexibility of all links, the governing equation of motion of a flexible link is formulated in the floating frame of reference using Euler-Lagrange method. A kineto-elasto dynamic model of the system is achieved, ready for modal analysis. Simulation in FEM software showed the similar modes with above computational result in typical location and rotation. The dynamic experiment presented the dominant modes and proved the theoretical analysis and simulation. The Diamond robot used in Lithium-ion battery sorting was taken as an example to demonstrate how to finish above studies. The result shows that the mechanism has good dynamic performance. The work is available for all parallel robots with flexible links.

scholarly journals Design and Analysis of a Novel Schönflies Motion Parallel Robot with Full Cycle Rotation

2021 ◽  
Author(s):  
Luquan Li ◽  
Yuefa Fang ◽  
Lin Wang ◽  
Jiaqiang Yao
Keyword(s):  
Complex Dynamics ◽  
Virtual Work ◽  
Parallel Robot ◽  
Singularity Analysis ◽  
Parallel Robots ◽  
The Novel ◽  
Scara Robot ◽  
Pick And Place ◽  
Place Task ◽  
Schönflies Motion

Abstract Due to the complex structures of multi-limbed parallel robots, conventional parallel robots generally have limited workspace, complex kinematics, and complex dynamics, which increases the application difficulty of parallel robot in industrial engineering. To solve the above problems, this paper proposes a single-loop Schönflies motion parallel robot with full cycle rotation, the robot can generate Schönflies motion by the most simplified structure. The novel Schönflies motion parallel robot is a two-limb parallel mechanism with least links and joints, and each limb is driven by a 2-degree of freedom (DOF) cylindrical driver (C-driver). The full cycle rotation of the output link is achieved by “…R-H…” structure, where the revolute (R) and helical (H) joints are coaxial. Mobility, kinematics, workspace and singularity analysis of novel Schönflies motion parallel robot are analyzed. Then, dynamic model is formulated based on the principle of virtual work. Moreover, a pick-and-place task is implemented by proposed Schönflies motion parallel robot and a serial SCARA robot, respectively. The simulation results verify the correctness of the theoretical model. Furthermore, dynamics performances of Schönflies motion parallel robot and serial SCARA robot are compared, which reveal the performance merits of proposed Schönflies motion parallel robot.

Investigation on the Vibration of High Speed Cable Robot Manipulation due to Tension Around Drum

2019 ◽  
Author(s):  
Jinwoo Jung ◽  
Jinlong Piao ◽  
Eunpyo Choi ◽  
Jong-Oh Park ◽  
Chang-Sei Kim
Keyword(s):  
High Speed ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Rigid Base ◽  
Robot System ◽  
Vibration Problem ◽  
Cable Robot ◽  
Pick And Place ◽  
Flexible Cables ◽  
Pick And Place Operation

Abstract A cable-driven parallel robot (CDPR) consists of an end-effector, flexible lightweight cables, pulleys, winches, and a rigid base frame. As opposed to the rigid links of the traditional serial robots and parallel robots, the flexible lightweight cables allow the CDPR to easily achieve the high speed, heavy payload manipulation, and scalable workspace. Especially, the conventional high-speed pick and place operation can be realized due to the lightweight of its flexible cables. However, the flexibility of the lightweight cables can introduce a considerable vibration problem to the high speed cable robot system. One of main causes can be a cable tension difference between initial pre-tension and winding tension around a drum of the winch-motor actuator. To effectively investigate the effect of the tension around the drum on the high speed manipulation of the cable robot system, the spatial eight-cable high speed cable robot was reduced to the horizontal two cable system. The reduction of the number of the cable enables us to minimize the influences from the other factors such as the cable sagging and the geometric errors. A series of experiments was conducted using the combinations of the low and high initial pre-tensions and low and high tensions around the drum. The experimental results clearly show that the low tension around the drum can cause the vibration problem during the high speed pick and place operation. Also, it demonstrates that securing the drum tension similar to the initial pre-tension can effectively reduce the magnitude of the vibration.

Delta Parallel Robot Based on Crank-Slider Mechanism

2017 ◽  
Vol 6 (2) ◽  
pp. 112
Author(s):  
Zhe Qin ◽  
Xiao-Chu Liu ◽  
Zhuan Zhao
Keyword(s):  
Parallel Robot ◽  
Force Transmission ◽  
Practical Application ◽  
Cartesian Space ◽  
Output Torque ◽  
Performance Indexes ◽  
Pick And Place ◽  
Delta Robot ◽  
Three Degree Of Freedom ◽  
Pick And Place Operation

A three-degree-of-freedom Delta parallel manipulator driven by a crank-slider mechanism is proposed. In Cartesian space, a gate-shaped curve is taken as the path of the pick-and-place operation, combining with the inverse kinematics theory of the Delta robot, and a mathematical model of robot statia force transmission is established. The force and the output torque of the robot-driven joint are taken as the main performance indexes, and the value of the crank-slider mechanism applied to Delta robot is further measured. The simulation results show that the delta robot driven by the crank slider mechanism can reduce the force and output torque of the driving joint during the picking and discharging operation, and has good practical application value.

Advanced Numerical Modeling of Nonlinear Elastic Cable With Permanent Stretch Using Cable Driven Parallel Robot

2017 ◽  
Author(s):  
Sung-Hyun Choi ◽  
Kyoung-Su Park
Keyword(s):  
Numerical Modeling ◽  
Steel Wire ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Cable Model ◽  
Lower Weight ◽  
Simulation Results ◽  
Nonlinear Elastic ◽  
Good Agreement ◽  
Elastic Characteristics

Since cable driven parallel robots (CDPRs) have many advantages, they have been used in many industrial fields. Fully constrained CDPRs mainly use Dyneema polyethylene because it has advantage of the lower weight than steel wire. However, the polyethylene cable has complex elastic characteristics (e.g. permanent stretch and hysteresis). In this paper, the advanced numerical modeling of nonlinear elastic cable with permanent stretch using cable driven parallel robot was derived and simulated for various cable condition. Based on the advanced numerical nonlinear cable model, the simulation was carried out under the various cable lengths and tensions. Compared to the experimental results, the simulation results are good agreement with the experimental data.

scholarly journals Optimal Kinematic Redundancy Planning for Planar Mobile Cable-Driven Parallel Robots

2018 ◽  
Author(s):  
Tahir Rasheed ◽  
Philip Long ◽  
David Marquez-Gamez ◽  
Stéphane Caro
Keyword(s):  
Parallel Robot ◽  
Parallel Robots ◽  
Degree Of Freedom ◽  
Static Equilibrium ◽  
Kinematic Redundancy ◽  
Pick And Place ◽  
Moving Platform ◽  
Three Degree Of Freedom

Mobile Cable-Driven Parallel Robots (MCDPRs) are special type of Reconfigurable Cable Driven Parallel Robots (RCDPRs) with the ability of undergoing an autonomous change in their geometric architecture. MCDPRs consists of a classical Cable-Driven Parallel Robot (CDPR) carried by multiple Mobile Bases (MBs). Generally MCDPRs are kinematically redundant due to the additional mobilities generated by the motion of the MBs. As a consequence, this paper introduces a methodology that aims to determine the best kinematic redundancy scheme of Planar MCDPRs (PMCDPRs) with one degree of kinematic redundancy for pick-and-place operations. This paper also discusses the Static Equilibrium (SE) constraints of the PMCDPR MBs that are needed to be respected during the task. A case study of a PMCDPR with two MBs, four cables and a three degree-of-freedom (DoF) Moving Platform (MP) is considered.

Development of a Five-Bar Parallel Robot With Large Workspace

2010 ◽  
Author(s):  
Lucas Campos ◽  
Francis Bourbonnais ◽  
Ilian A. Bonev ◽  
Pascal Bigras
Keyword(s):  
Parallel Robot ◽  
Parallel Robots ◽  
Industrial Grade ◽  
Pick And Place

Five-bar planar parallel robots for pick and place operations are always designed so that their singularity loci are significantly reduced. In these robots, the length of the proximal links is different from the length of the distal links. As a consequence, the workspace of the robot is significantly limited, since there are holes in it. In contrast, we propose a design in which all four links have equal lengths. Since such a design leads to more parallel singularities, a strategy for avoiding them by switching working modes is proposed. As a result, the usable workspace of the robot is significantly increased. The idea has been implemented on an industrial-grade prototype and the latter is described in detail.

scholarly journals Vision-Based Hybrid Controller to Release a 4-DOF Parallel Robot from a Type II Singularity

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4080
Author(s):  
José L. Pulloquinga ◽  
Rafael J. Escarabajal ◽  
Jesús Ferrándiz ◽  
Marina Vallés ◽  
Vicente Mata ◽  
...  
Keyword(s):  
Vision System ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Human Robot Interaction ◽  
Type Ii ◽  
Hybrid Controller ◽  
Knee Rehabilitation ◽  
System Data ◽  
Singular Configuration

The high accuracy and dynamic performance of parallel robots (PRs) make them suitable to ensure safe operation in human–robot interaction. However, these advantages come at the expense of a reduced workspace and the possible appearance of type II singularities. The latter is due to the loss of control of the PR and requires further analysis to keep the stiffness of the PR even after a singular configuration is reached. All or a subset of the limbs could be responsible for a type II singularity, and they can be detected by using the angle between two output twist screws (OTSs). However, this angle has not been applied in control because it requires an accurate measure of the pose of the PR. This paper proposes a new hybrid controller to release a 4-DOF PR from a type II singularity based on a real time vision system. The vision system data are used to automatically readapt the configuration of the PR by moving the limbs identified by the angle between two OTSs. This controller is intended for a knee rehabilitation PR, and the results show how this release is accomplished with smooth controlled movements where the patient’s safety is not compromised.

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