Five Bar Planar Manipulator Simulation and Analysis by Bond Graph

Author(s):  
Shengqi Jian ◽  
Cheng Yin ◽  
Luc Rolland ◽  
Lesley James

This work focuses on the bond graph modelling method and its application on multi-body system, especially on the five-bar parallel robot. Five-bar parallel robot is comprised of four arms, two revolute actuators and five revolute joints. This paper adopts five-bar parallel robot in symmetric configuration as simulation object. As it will be used as a pickup and placing machine, its workspace is fixed on Cartesian coordinate. The relationship between the two rotating angles and end effector’s desire position is built by inverse kinematics. Bond graph is used to describe moment, torque, velocity, angle relationships. In this project, the dynamic performances between arms, motors at robot basement and end effector will be researched. In this paper, an investigation about how to use bond graph to model DC (direct current) servo motor and an integrated motion control system is carried out. During a typical end effector point-point displacement, the torque change between arms is plotted. Finally, 3-D animation experiment is conducted. Experiment results show that bond graph can simulate robot dynamics performance without having to make a large number of equations. It is able to simulate and solve five-bar kinematics problem in the process.

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3403 ◽  
Author(s):  
Rodriguez-Barroso ◽  
Saltaren ◽  
Portilla ◽  
Cely ◽  
Yakrangi

Cable-driven parallel robots with a redundant configuration have infinite solutions for their cable tension distribution to provide a specific wrench to the end-effector. Redundancy is commonly used to increase the workspace and stiffness or to achieve secondary objectives like energetic minimization or additional movements. This article presents a method based on energy distribution to handle the redundancy of cable-driven parallel robots. This method allows the deformation and tension of each link to be related to the total energy available in the parallel robot. The study of energy distribution expression allows deformation, tension, and position to be combined. It also defines the range of tension and deformation that cables can achieve without altering the wrench exerted on the end-effector. This range is used with a passive reconfigurable end-effector to control the position of two grippers attached to some cables which act as compliant actuators. The relationship between the actuators’ energy and their corresponding gripper positions is also provided. In this way, energy measurement from the actuators allows the grasping state to be sensed. The results are validated using multibody dynamic software.


2012 ◽  
Vol 463-464 ◽  
pp. 1116-1119 ◽  
Author(s):  
Monica Loredana Enescu ◽  
Cătălin Alexandru

The purpose of this paper is to model and simulate a 6 DOF robotic system with revolute joints. This is in order to optimize the motion law which results in uniform coating deposited by spray pyrolysis. The structure and the complexity of the robotic system are determined by the necessary movements in the spray pyrolysis process. The nozzle (end-effector of the robot manipulator) has two translations, in longitudinal and transversal direction relative to the surface deposition. The mechanical model of the robot mechanism was developed by using the MBS (Multi Body Systems) environment ADAMS of MSC Software.


2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Loïc Cuvillon ◽  
Xavier Weber ◽  
Jacques Gangloff

Abstract Cable-driven parallel robots are well suited for applications that require a very large workspace. Thanks to their lightweight moving parts, they can achieve high dynamics while remaining pretty safe for nearby human workers. Furthermore, their size depends only on the length of the cables; thus, their scale is almost totally decoupled from their cost. However, due to the cables, the stiffness is very low with respect to rigid link robots, inducing slowly damped oscillations of the end effector. Previous works have shown that those vibrations can be effectively damped by the winch actuators thanks to active vibration damping techniques. In this paper, a gain scheduling approach is proposed based on a linearized model of the robot dynamics. This model is projected in the modal space yielding six decoupled transfer functions for six degrees-of-freedom (DoFs) of a cable-driven parallel robot using thin cables. The stability of the proposed control law is analyzed for a static and a moving end effector. The proposed control algorithm is validated experimentally on an eight-cable suspended robot prototype.


Author(s):  
K. Azizian ◽  
P. Cardou ◽  
B. Moore

The wrench-closure workspace of parallel cable-driven mechanisms is the set of poses for which any wrench can be produced at the end-effector by a set of a non-negative cable tensions. It is already known that the boundary of the constant-orientation wrench-closure workspace of a planar parallel cable-driven mechanism is composed of segments of conic sections. However, the relationship between the geometry of the mechanism and the types of these conic sections is unknown. This paper proposes a graphical method for determining the types of these conic sections. It is also shown that the proposed method can be applied to find the constant-orientation singularities of a 3-RPR planar parallel robot, since these contours correspond to the boundary segment of the analogous three-cable driven planar parallel mechanism.


Author(s):  
Oleksandr Stepanenko ◽  
Ilian A. Bonev

In this paper, we present a novel 4-DOF SCARA parallel robot. The 2-DOF portion of the novel robot has been proposed before and consists of an end-effector connected to the base through two legs of type RRR and one passive constraining leg of type RP, where all the base-mounted revolute joints are coaxial. Contrary to SCARA robots based on the four-bar mechanism (RRRRR), the novel robot has a fully cylindrical workspace with no voids or parallel singularities in it. The novel robot has essentially the same workspace as that of a similarly sized ceiling-mounted SCARA serial robot (RR) with links of equal length. However, the proposed robot has the advantage of having all motors mounted on the base. We present the 2-DOF portion of the robot, its kinematic analysis, and its optimal design, and finally propose a mechanism design for the 4-DOF SCARA parallel robot.


2012 ◽  
Vol 4 (2) ◽  
Author(s):  
K. Azizian ◽  
P. Cardou ◽  
B. Moore

The wrench-closure workspace of parallel cable-driven mechanisms is the set of poses for which any wrench can be produced at the end-effector by a set of non-negative cable tensions. It is already known that the boundary of the constant-orientation wrench-closure workspace of a planar parallel cable-driven mechanism is composed of segments of conic sections. However, the relationship between the geometry of the mechanism and the types of these conic sections is unknown. This technical report proposes a graphical method for determining the types of these conic sections from the mechanism geometry. It is also shown that the proposed method can be applied to find the constant-orientation singularities of a 3-RPR planar parallel robot, since these conic sections correspond to the boundary segment of the analogous three-cable driven planar parallel mechanism.


2013 ◽  
Vol 290 ◽  
pp. 91-96 ◽  
Author(s):  
Hai Tao Luo ◽  
Zheng Cang Chen ◽  
Yu Quan Leng ◽  
Hong Guang Wang

This paper mainly investigated the rigid-flexible dynamics simulation method of multi-body system. The 3-RPS parallel robot dynamics model is created by ADAMS (multi-body dynamics software) and ANSYS (finite element analysis software). In accordance with the flexible-body theory, we analyzed mechanical characteristics of parallel robot with no-load or full-load working condition, and got the deformation of end measuring point, maximum stress position and dynamics stress curve. The analysis method is more intuitional and accurate, and can increase the accuracy of dynamic response analysis of links under the dynamic loads. The simulation results create conditions for structure design and optimization of 3-RPS parallel robot.


2012 ◽  
Vol 232 ◽  
pp. 414-418 ◽  
Author(s):  
S. Nader Nabavi ◽  
Alireza Akbarzadeh ◽  
Saeed Abolghasemi

In this paper, kinematic relationships for a 3-PRR planar parallel robot are first presented. The robot dynamics equations are formulated using Lagrange equations of first kind. The derived equations are a mixed set of differential and algebraic constraint equations, DAE, which must be satisfied simultaneously. In order to solve the robot dynamic equations, a new method is presented in which the dynamics equation is first partitioned into two parts. The constraint equations and the dependent coordinates are next eliminated. This reduces the dynamic equations to a set of differential equations as a function of three independent coordinates. Finally, a trajectory for the robot end-effector is specified and PD controller which follows the desired trajectory is implemented. The proposed method significantly simplifies the solution of the dynamics equations.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2765 ◽  
Author(s):  
Alejandro Rodriguez-Barroso ◽  
Roque Saltaren ◽  
Gerardo A. Portilla ◽  
Juan S. Cely ◽  
Marco Carpio

Redundancy in cable-driven parallel robots provides additional degrees of freedom that can be used to achieve different objectives. In this robot, this degree of freedom is used to act on a reconfigurable end effector with one degree of freedom. A compliant actuator actuated by one motor exerts force on both bodies of the platform. Due to the high tension that appears in this cable in comparison with the rest of the cables, an elastic model was developed for solving the kinestostatic and wrench analysis. A linear sensor was used in one branch of this cable mechanism to provide the needed intermediate values. The position of one link of the platform was fixed in order to focus this analysis on the relationship between the cables and the platform’s internal movement. Position values of the reconfigurable end effector were calculated and measured as well as the tension at different regions of the compliant actuator. The theoretical values were compared with dynamic simulations and real prototype results.


Author(s):  
DU Hui ◽  
GAO Feng ◽  
PAN Yang

A novel 3-UP3R parallel mechanism with six degree of freedoms is proposed in this paper. One most important advantage of this mechanism is that the three translational and three rotational motions are partially decoupled: the end-effector position is only determined by three inputs, while the rotational angles are relative to all six inputs. The design methodology via GF set theory is brought out, using which the limb type can be determined. The mobility of the end-effector is analyzed. After that, the kinematic and velocity models are formulated. Then, workspace is studied, and since the robot is partially decoupled, the reachable workspace is also the dexterous workspace. In the end, both local and global performances are discussed using conditioning indexes. The experiment of real prototype shows that this mechanism works well and may be applied in many fields.


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