Bond Graph Modeling and Simulating of 3 RPR Planar Parallel Manipulator

Author(s):  
Cheng Yin ◽  
Shengqi Jian ◽  
Md. Hassan Faghih ◽  
Md. Toufiqul Islam ◽  
Luc Rolland

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.

Author(s):  
Abbas Fattah ◽  
Arun K. Misra ◽  
Jorge Angeles

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.


2011 ◽  
Vol 467-469 ◽  
pp. 1351-1356
Author(s):  
Xiao Rong Zhu ◽  
Hui Ping Shen ◽  
Wei Zhu

A kind of 2-DOF parallel manipulator driven by two sliders moving along two parallel guides is analyzed. Based on the explicit expression of inverse position, velocity and acceleration analyses, the mobile trajectory of this manipulator is investigated and simulated. In trajectory planning, the trajectory profiles are assigned to be accelerated and decelerated at the first and last few seconds, respectively, and keep at constant speed for the remainder of time, where the forth-order polynomial is fitted during acceleration and deceleration, and clothoid curve is applied around the corner of axis. Then the mobile rule exerted on the actuator sliders is obtained using inverse position based on the desired end-effecter trajectory. Finally, the virtual prototype of this mechanism is modeled using Solidwork and the kinematics and dynamics simulation is performed using Cosmostion. The result shows that both velocity, acceleration of the sliders and the driving force exerted on the sliders are continuous curves, which can fully satisfy the demand of high-accuracy and real-time processing of the high-speed Manipulator.


Author(s):  
Zhengsheng Chen ◽  
Minxiu Kong

To obtain excellent comprehensive performances of the planar parallel manipulator for the high-speed application, an integrated optimal design method, which integrated dimensional synthesis, motors/reducers selection, and control parameters tuning, is proposed, and the 3RRR parallel manipulator was taken as the example. The kinematic and dynamic performances of condition number, velocity index, acceleration capability, and low-order frequency are taken into accounts for the dimensional synthesis. Then, to match motors/reducers parameters and keep an economical cost, the constraint equations and the parameters library are built, and the cost is chosen as one of the optimization objectives. Also, to get high tracking accuracy, the dynamic forward plus proportional–derivative control scheme is introduced, and the tracking error is chosen as one of the optimization objectives. Hence, the optimization model including dimensional synthesis, motors/reducers selection and controller parameters tuning is established, which is solved by the genetic algorithm II (NSGA-II). The result shows that comprehensive performances can be effectively promoted through the proposed integrated optimal design, and the prototype was constructed according to the Pareto-optimal front.


2001 ◽  
Author(s):  
R. C. Rosenberg ◽  
E. D. Goodman ◽  
Kisung Seo

Abstract Mechatronic system design differs from design of single-domain systems, such as electronic circuits, mechanisms, and fluid power systems, in part because of the need to integrate the several distinct domain characteristics in predicting system behavior. The goal of our work is to develop an automated procedure that can explore mechatronic design space in a topologically open-ended manner, yet still find appropriate configurations efficiently enough to be useful. Our approach combines bond graphs for model representation with genetic programming for generating suitable design candidates as a means of exploring the design space. Bond graphs allow us to capture the common energy behavior underlying the several physical domains of mechatronic systems in a uniform notation. Genetic programming is an effective way to generate design candidates in an open-ended, but statistically structured, manner. Our initial goal is to identify the key issues in merging the bond graph modeling tool with genetic programming for searching. The first design problem we chose is that of finding a model that has a specified set of eigenvalues. The problem can be studied using a restricted set of bond graph elements to represent suitable topologies. We present the initial results of our studies and identify key issues in advancing the approach toward becoming an effective and efficient open-ended design tool for mechatronic systems.


1994 ◽  
Vol 116 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Chiaming Yen ◽  
Glenn Y. Masada

An Extended Bond Graph (EBG) formulation is described for analyzing the dynamics of a flexible multibody system. This work extends the EBG method, which was originally developed for systems with small spatial motion, to rigid and flexible multibody systems exhibiting large overall motions. The development uses modular models for the elements so that complex system models can be derived by coupling these modules. The EBG formulation for moving reference frames is used to derive models of one-link and two-link flexible manipulator systems. This approach has several advantages over the Lagrangian and Newtonian methods, such as its ability to solve the forward and inverse dynamic problems using the same bond graph. Finally, the EBG formulations for cantilever beams and for multi-rigid body dynamic systems are shown to be special cases of the general EGBs for flexible bodies.


2005 ◽  
Vol 128 (4) ◽  
pp. 976-979 ◽  
Author(s):  
Lu Ren ◽  
James K. Mills ◽  
Dong Sun

In this paper, we develop a new control method, termed adaptive synchronized (A-S) control, for improving tracking accuracy of a P-R-R type planar parallel manipulator with parametric uncertainty. The novelty of A-S control, a combination of synchronized control and adaptive control, is in the application of synchronized control to a single parallel manipulator so that tracking accuracy is improved during high-speed, high-acceleration tracking motions. Through treatment of each chain as a submanipulator; the P-R-R manipulator is thus modeled as a multi-robot system comprised of three submanipulators grasping a common payload. Considering the geometry of the platform, these submanipulators are kinematically constrained and move in a synchronous manner. To solve this synchronization control problem, a synchronization error is defined, which represents the coupling effects among the submanipulators. With the employment of this synchronization error, tracking accuracy of the platform is improved. Simultaneously, the estimated unknown parameters converge to their true values through the use of a bounded-gain-forgetting estimator. Experiments conducted on the P-R-R manipulator demonstrate the validity of the approach.


2014 ◽  
Vol 541-542 ◽  
pp. 792-797
Author(s):  
Roshdy Foaad Abo-Shanab

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.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Yunkai Wu ◽  
Bin Jiang ◽  
Ningyun Lu ◽  
Yang Zhou

Reliability of the traction system is of critical importance to the safety of CRH (China Railway High-speed) high-speed train. To investigate fault propagation mechanism and predict the probabilities of component-level faults accurately for a high-speed railway traction system, a fault prognosis approach via Bayesian network and bond graph modeling techniques is proposed. The inherent structure of a railway traction system is represented by bond graph model, based on which a multilayer Bayesian network is developed for fault propagation analysis and fault prediction. For complete and incomplete data sets, two different parameter learning algorithms such as Bayesian estimation and expectation maximization (EM) algorithm are adopted to determine the conditional probability table of the Bayesian network. The proposed prognosis approach using Pearl’s polytree propagation algorithm for joint probability reasoning can predict the failure probabilities of leaf nodes based on the current status of root nodes. Verification results in a high-speed railway traction simulation system can demonstrate the effectiveness of the proposed approach.


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