scholarly journals Dynamic analysis and optimization of a kinematically redundant planar parallel manipulator

2018 ◽  
Vol 42 (1) ◽  
pp. 20-29 ◽  
Author(s):  
Roger Boudreau ◽  
Jérémie Léger ◽  
Hakim Tinaou ◽  
André Gallant
Keyword(s):  
Dynamic Analysis ◽  
Objective Function ◽  
Dynamic Model ◽  
Parallel Manipulator ◽  
Optimization Method ◽  
Acceptable Solution ◽  
End Effector ◽  
Planar Parallel Manipulator ◽  
Static Approach

This paper presents the dynamic model of a kinematically redundant planar parallel manipulator and an optimization method to minimize the actuator torques when the end-effector is subjected to a wrench while following a trajectory. A previous study proposed a static approach to solve the same problem. The objective of the work presented here was to verify if the static assumption was valid. Including the dynamic model in the optimization produced some undesirable oscillations and required the use of a different objective function. It is shown that for the application considered, the static approach provided an acceptable solution.

Vibration Control for Parallel Manipulator Based on the Feed Forward Control Strategy

2013 ◽  
Author(s):  
Ming Li ◽  
Huapeng Wu ◽  
Heikki Handroos ◽  
Marco Ceccarelli ◽  
Giuseppe Carbone
Keyword(s):  
Control System ◽  
Dynamic Model ◽  
Control Strategy ◽  
Parallel Manipulator ◽  
External Disturbance ◽  
Machining Process ◽  
End Effector ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Model Based

Due to the high stiffness, high dynamic performance, the parallel manipulator presents great advantages in the industrial manufacture. However in the machining process, the external low frequency disturbance, e.g. the varying cutting force, has a significant effect on the control system of parallel manipulator, which presents a chatter phenomenon on the end-effector of manipulator. In this paper, a feed forward control strategy is proposed to eliminate the effect of the random external disturbance on the control system of parallel manipulator. By applying the external disturbance force on the inverse dynamic model, the compensation torque is calculated and fed forward into the manipulator driving joints to cancel out the effect of the disturbance acting on the manipulator end-effector. The key issue herein is to be able to establish the accurate dynamic model for the parallel manipulator. Furthermore, in order to guarantee the position precision of the manipulator, a feed forward model-based control strategy combined with the feedback loop PV (position and velocity) control has been developed based on the reference trajectory, which could relatively simplify the highly nonlinear control system of the parallel manipulator and obtain a stable tracking error model. The whole research has been carried out on a parallel manipulator named CaPaMan which has been built in the laboratory of robotics and mechatronics in university of Cassino and South Latium. The results show that the chatter phenomenon could be utterly depressed by the force compensation from the feed forward path of the external disturbance; meanwhile the model-based controller can guarantee the trajectory tracking accuracy within a stable error by choosing the suitable PV gains.

Effect of Changing the Position of Tool Point on the Moving Platform on the Kinematics of a 3RRR Planar Parallel Manipulator

2014 ◽  
Vol 541-542 ◽  
pp. 792-797
Author(s):  
Roshdy Foaad Abo-Shanab
Keyword(s):  
Parallel Manipulator ◽  
Performance Criteria ◽  
Mobile Platform ◽  
Optimum Location ◽  
End Effector ◽  
Global Indices ◽  
Reachable Workspace ◽  
Planar Parallel Manipulator ◽  
Moving Platform ◽  
Structural Length

This paper discusses the effect of changing the location of the tool point, on the mobile platform, on the kinematics of a planar parallel manipulator. It is shown that changing the position of the end-effector greatly changes the shape and the area of the reachable workspace. Global conditioning index and the structural length index are used as global indices to find the optimum location of the end-effector on the mobile platform of a parallel manipulator. The results show that the performance criteria are varying in opposite directions, the dexterity is decreasing when the workspace area is increasing. Hence, the problem of optimal design becomes a problem of determination an acceptable compromise between the two requirements. The results of the present work show that the position of the end-effector on the mobile platform should be considered while optimizing the performance of a parallel manipulator.

scholarly journals Simulation and Optimisation of a Two Degree of Freedom, Planar, Parallel Manipulator

2021 ◽  
Author(s):  
◽  
Ben Haughey
Keyword(s):  
Genetic Algorithm ◽  
Simulation Model ◽  
Cycle Time ◽  
Parallel Manipulator ◽  
Robotic Manipulators ◽  
Degree Of Freedom ◽  
End Effector ◽  
Planar Parallel Manipulator ◽  
Pick And Place ◽  
Two Degree Of Freedom

<p>Development in pick-and-place robotic manipulators continues to grow as factory processes are streamlined. One configuration of these manipulators is the two degree of freedom, planar, parallel manipulator (2DOFPPM). A machine building company, RML Engineering Ltd., wishes to develop custom robotic manipulators that are optimised for individual pick-and-place applications. This thesis develops several tools to assist in the design process. The 2DOFPPM’s structure lends itself to fast and accurate translations in a single plane. However, the performance of the 2DOFPPM is highly dependent on its dimensions. The kinematics of the 2DOFPPM are explored and used to examine the reachable workspace of the manipulator. This method of analysis also gives insight into the relative speed and accuracy of the manipulator’s end-effector in the workspace. A simulation model of the 2DOFPPM has been developed in Matlab’s® SimMechanics®. This allows the detailed analysis of the manipulator’s dynamics. In order to provide meaningful input into the simulation model, a cubic spline trajectory planner is created. The algorithm uses an iterative approach of minimising the time between knots along the path, while ensuring the kinematic and dynamic limits of the motors and end-effector are abided by. The resulting trajectory can be considered near-minimum in terms of its cycle-time. The dimensions of the 2DOFPPM have a large effect on the performance of the manipulator. Four major dimensions are analysed to see the effect each has on the cycle-time over a standardised path. The dimensions are the proximal and distal arms, spacing of the motors and the height of the manipulator above the workspace. The solution space of all feasible combinations of these dimensions is produced revealing cycle-times with a large degree of variation over the same path. Several optimisation algorithms are applied to finding the manipulator configuration with the fastest cycle-time. A random restart hill-climber, stochastic hill-climber, simulated annealing and a genetic algorithm are developed. After each algorithm’s parameters are tuned, the genetic algorithm is shown to outperform the other techniques.</p>

Dynamics of a Flexible-Link Planar Parallel Manipulator in Cartesian Space

1994 ◽  
Author(s):  
Abbas Fattah ◽  
Arun K. Misra ◽  
Jorge Angeles
Keyword(s):  
Parallel Manipulator ◽  
High Speed ◽  
Inverse Dynamics ◽  
Equations Of Motion ◽  
Flexible Link ◽  
End Effector ◽  
Joint Torques ◽  
Flexible Links ◽  
Cartesian Space ◽  
Planar Parallel Manipulator

Abstract The subject of this paper is the modeling and simulation of a flexible-link planar parallel manipulator in Cartesian space. Given a desired end-effector motion, the inverse kinematics and inverse dynamics of a rigid-link model of the parallel manipulator is used to obtain actuated joint torques. The actual end-effector motion and vibration of the flexible links are obtained using simulation (direct dynamics) for the flexible-link manipulator. Finite elements are used to model the flexible links, while the Euler-Lagrange formulation is used to derive the equations of motion of the uncoupled links. The equations of motion of all the links are assembled to obtain the governing equations for the entire system. The methodology of the natural orthogonal complement, which has been previously applied to flexible-link systems with open-chain structures, is used here to eliminate the constraint forces. Finally, geometric nonlinearities in elastic deformations, which are very important in high-speed operations, are also considered.

Kinematic and Dynamic Analysis of Parallel Manipulators by Means of Motor Algebra

1987 ◽  
Vol 109 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Koichi Sugimoto
Keyword(s):  
Dynamic Analysis ◽  
Dynamic Model ◽  
Parallel Manipulator ◽  
Parallel Manipulators ◽  
Joint Torques

The derivation of a kinematic and dynamic model for a parallel manipulator is presented in this paper. The model can be used to calculate displacements, velocities, and accelerations of both joints and links, and also joint torques and forces required to drive a manipulator. The expression in this paper, which is derived using the motor algebra and the Newton-Euler formulation, can be applied to many kinds of parallel manipulators.

Bond Graph Modeling and Simulating of 3 RPR Planar Parallel Manipulator

2014 ◽  
Author(s):  
Cheng Yin ◽  
Shengqi Jian ◽  
Md. Hassan Faghih ◽  
Md. Toufiqul Islam ◽  
Luc Rolland
Keyword(s):  
Parallel Manipulator ◽  
High Speed ◽  
Reference Frames ◽  
Bond Graph ◽  
Dynamics Simulation ◽  
Bond Graphs ◽  
End Effector ◽  
Planar Parallel Manipulator ◽  
Bond Graph Modeling ◽  
Graph System

A 3-RPR planar parallel robot is a kind of planar mechanisms, which can work at high speed, with high accuracy and high rigidity. In this paper, a multi-body bond graph system will be built for the 3-RPR planar parallel manipulator (PPM), along with 3 PID controllers which give commands to 3 DC motors respectively. The advantage of bond graphs is that they can integrate different types of dynamics systems, the manipulator, the control and the motor can be modelled and simulated altogether in the same process. Bond graph will be established for each rigid body with body-fixed coordinate’s reference frames, which are connected with parasitic elements (damping and compliance) to each other. The PID set-point signals are generated by the explicit inverse kinematic equations. The 3 prismatic lengths constitute the measured feedback signals. In order to make the end-effector reach the ideal position with target orientation, the three links should reach the target lengths simultaneously. In this study, the dynamics simulation of 3-RPR PPM is conducted after building the bond graph system. As the 3 motors are working simultaneously and independently, the end-effector will arrive to the expected position. Finally, the bond graph and control system are validated with the compiled results and 3D animation. Force plot and torque plot will be generated as dynamics performance. Moreover, kinematics of manipulators are also calculated using bond graph. Eventually, bond graphs are shown to be effective in solving not only dynamic but also kinematic problems.

scholarly journals Integrating Dynamics into Design and Motion Optimization of a 3-PRR Planar Parallel Manipulator with Discrete Time Transfer Matrix Method

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Guoning Si ◽  
Mengqiu Chu ◽  
Zhuo Zhang ◽  
Haijie Li ◽  
Xuping Zhang
Keyword(s):  
Dynamic Model ◽  
Dynamic Modeling ◽  
Discrete Time ◽  
Parallel Manipulator ◽  
Robot Manipulators ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Time Transfer ◽  
Performance Indices ◽  
Planar Parallel Manipulator

This paper presents a novel method of dynamic modeling and design optimization integrated with dynamics for parallel robot manipulators. Firstly, a computationally efficient modeling method, the discrete time transfer matrix method (DT-TMM), is proposed to establish the dynamic model of a 3-PRR planar parallel manipulator (PPM) for the first time. The numerical simulations are performed with both the proposed DT-TMM dynamic modeling and the ADAMS modeling. The applicability and effectiveness of DT-TMM in parallel manipulators are verified by comparing the numerical results. Secondly, the design parameters of the 3-PRR parallel manipulator are optimized using the kinematic performance indices, such as global workspace conditioning index (GWCI), global condition index (GCI), and global gradient index (GGI). Finally, a dynamic performance index, namely, driving force index (DFI), is proposed based on the established dynamic model. The described motion trajectory of the moving platform is placed into the optimized workspace and the initial position is determined to finalize the end-effector trajectory of the parallel manipulator by the further optimization with the integrated kinematic and dynamic performance indices. The novelty of this work includes (1) developing a new dynamic model method with high computation efficiency for parallel robot manipulators using DT-TMM and (2) proposing a new dynamic performance index and integrating the dynamic index into the motion and design optimization of parallel robot manipulators.

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