Dynamics Analysis of a Controllable Mechanism

Author(s):  
Zhang Ke ◽  
Wang Shengze

Hybrid mechanism is a kind of controllable mechanism. It may be composed of one or multiple coupled kinematic loops forming a mechanism network, and is highly nonlinear devices. The bond graph approach provides a compact and versatile representation for kinematics and dynamics of hybrid mechanism, and is more suitable for automatic derivation and computation on a computer. Here, an analysis procedure that can be used to produce the dynamics equations of hybrid mechanism is presented. According to bond graph model, dynamics equations can be derived. The unified formula of dynamics equations derived here is a regularized one. The driving powers of hybrid mechanism can be obtained in terms of physical parameters of mechanism and kinematic states, and no need to analyze acceleration of mechanism. Finally, a numerical example is presented illustrating its validity. The results show that efficiency and reliability of dynamics analysis for hybrid mechanism are enhanced obviously.

Author(s):  
Ke Zhang

A hybrid five bar mechanism is a typical planar parallel robot. It is a configuration that combines the motions of two characteristically different motors by means of a five bar mechanism to produce programmable output. Hybrid five bar mechanism is the most representative one of hybrid mechanism. In this paper, considering the bond graph can provide a compact and versatile representation for kinematics and dynamics of hybrid mechanism, the dynamics analysis for a hybrid five-bar mechanism based on power bond graph theory is introduced. Then an optimization design of hybrid mechanism is performed with reference to dynamic objective function. By the use of the properties of global search of genetic algorithm (GA), an improved GA algorithm is proposed based on real-code. Optimum dimensions are obtained assuming there are no dimensional tolerances or clearances. Finally, a numerical example is carried out, and the simulation result shows that the optimization method is feasible and satisfactory in the design of hybrid mechanism.


2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878285 ◽  
Author(s):  
Jian Zhao ◽  
Zhiqiang Hu ◽  
Bing Zhu ◽  
Jiapeng Gong

Brake system is an important actuator of most active safety systems equipped on vehicles. It combines with the wheel to make vehicle decelerate and finally stop it. Moreover, brake system is an electronic, mechanical, and hydraulic hybrid system; it contains some highly nonlinear characters, which is a challenge to system control. In this article, an integrated model of brake system and single-wheel system using bond graph method is developed, in which the nonlinear characters of the volumetric compliance effect of brake fluid and the resistance effect of valves are taken into consideration. The accuracy and reliability of the brake system is verified by experiment. Nonlinear sliding-mode controller as well as sliding-mode observer is proposed. The controller is used to modulate inlet and outlet valves control signals according to the vehicle states, which will lead to cancel the usage of wheel cylinder pressure sensors. The controller is analyzed by different tire–road friction coefficient conditions. The results show that the proposed integrated bond graph model is accurate, and the nonlinear sliding-mode control is reliable on valves control signal regulation.


Author(s):  
Gopisetti Srinivasarao ◽  
Arun K Samantaray ◽  
Sanjoy K Ghoshal

The dynamics of a twin-rotor multi-input multi-output system, which is similar to that of a helicopter in many ways, is highly nonlinear in nature. In this article, a detailed dynamical model of twin-rotor multi-input multi-output system is developed and simulated by using bond graph approach. Nonlinear nature of the interface gain, thrust, and drag forces, and the stiffness of cable attached to support column joint are estimated. The rotors are modeled through the Newton–Euler equations. The bond graph model is created by using the generic sub-models and the same set of sub-models can be assembled differently to model many other similar systems such as tricopters and quadcopters. Inertial forces and moments, rotor thrust and drag forces, active and reactive motor torques, and direct current motor dynamics are considered in the model. The responses from the model are compared with the test data for validation.


2008 ◽  
Vol 1 (06) ◽  
pp. 329-334
Author(s):  
S. Rabih ◽  
C. Turpin ◽  
S. Astier

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110336
Author(s):  
Safia Akram ◽  
Maria Athar ◽  
Khalid Saeed ◽  
Alia Razia

The consequences of double-diffusivity convection on the peristaltic transport of Sisko nanofluids in the non-uniform inclined channel and induced magnetic field are discussed in this article. The mathematical modeling of Sisko nanofluids with induced magnetic field and double-diffusivity convection is given. To simplify PDEs that are highly nonlinear in nature, the low but finite Reynolds number, and long wavelength estimation are used. The Numerical solution is calculated for the non-linear PDEs. The exact solution of concentration, temperature and nanoparticle are obtained. The effect of various physical parameters of flow quantities is shown in numerical and graphical data. The outcomes show that as the thermophoresis and Dufour parameters are raised, the profiles of temperature, concentration, and nanoparticle fraction all significantly increase.


2021 ◽  
Vol 10 (1) ◽  
pp. 39-45
Author(s):  
S. Kumbinarasaiah ◽  
K.R. Raghunatha

Abstract In this article, we present the Laguerre wavelet exact Parseval frame method (LWPM) for the two-dimensional flow of a rotating micropolar fluid in a porous channel with huge mass transfer. This flow is governed by highly nonlinear coupled partial differential equations (PDEs) are reduced to the nonlinear coupled ordinary differential equations (ODEs) using Berman's similarity transformation before being solved numerically by a Laguerre wavelet exact Parseval frame method. We also compared this work with the other methods in the literature available. Moreover, in the graphs of the velocity distribution and microrotation, we shown that the proposed scheme's solutions are more accurate and applicable than other existing methods in the literature. Numerical results explaining the effects of various physical parameters connected with the flow are discussed.


1975 ◽  
Vol 97 (2) ◽  
pp. 184-188 ◽  
Author(s):  
A. S. Perelson

The lack of arbitrariness in the choice of bond graph sign conventions is established. It is shown that an unoriented bond graph may have no unique meaning and that with certain choices of orientation a bond graph may not correspond to any lumped parameter system constructed from the same set of elements. Network interpretations of these two facts are given. Defining a bond graph as an oriented object leads to the consideration of equivalence classes of oriented bond graphs which represent the same system. It is also shown that only changes in the orientation of bonds connecting 0-junctions and 1-junctions can lead to changes in the observable properties of a bond graph model.


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