scholarly journals A Dynamic Modeling Method for the Bi-Directional Pneumatic Actuator Using Dynamic Equilibrium Equation

Actuators ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 7
Author(s):  
Yiqing Li ◽  
Wen Zhou ◽  
Junwu Wu ◽  
Guoxu Hu

Dynamic modeling of soft pneumatic actuators are a challenging research field. In this paper, a dynamic modeling method used for a bi-directionaly soft pneumatic actuator with symmetrical chambers is proposed. In this dynamic model, the effect of uninflated rubber block on bending deformation is considered. The errors resulting from the proposed dynamic equilibrium equation are analyzed, and a compensation method for the dynamic equilibrium equation is proposed. The equation can be solved quickly after simplification. The results show that the proposed dynamic model can describe the motion process of the bi-directional pneumatic actuator effectively.

2011 ◽  
Vol 88-89 ◽  
pp. 657-661 ◽  
Author(s):  
Yi Fang He ◽  
Sha Nen Yu ◽  
Qun Li Shang ◽  
Fu Kai Deng

Pneumatic operated spring-diaphragm actuator is the most popular acting device in industrial applications. Precise modelling of pneumatic actuator continues to remain a major challenge because of its nonlinear characteristic. In this work, the characteristics of pneumatic actuator are analysed in details, and then the dynamic model, which considers effects of stem friction and compressibility of air, is developed. Computer simulation and experimental tests have been carried out on the developed model. The results show the model has a better performance.


Author(s):  
R. A. Hart ◽  
N. D. Ebrahimi

Abstract This two-part paper presents a dynamic model of a legged vehicle for travel on a variable-topographic terrain. In Part 1 of the paper, we develop expressions for the kinematics of the vehicular system. These expressions, in turn, form the foundation for the dynamic analysis of the robotic vehicle presented in Part 2 of the paper. The model applies to a system composed of a cargocarrying body supported by four multi-degree-of-freedom linkage assemblies whose configurations are adjustable to accommodate terrain irregularities. The mobility of the locomotion system is provided by four rigid wheels which serve as a base to the kinematic chains that extend from the platform of the vehicle. To assure dynamic equilibrium of all members in the system, torque actuators are employed at the joints between inter-connecting bodies to facilitate the adjustment of each articulated chain configuration without reducing the adaptability of the vehicle to ground profile variations. The dynamic model used for determining the system response to environmental contact forces is based on a Newton-Euler recursive formulation.


2021 ◽  
Vol 2 (1) ◽  
pp. 63-80
Author(s):  
Noushad Bin Jamal Bin Jamal M ◽  
Hsiao Wei Lee ◽  
Chebolu Lakshmana Rao ◽  
Cemal Basaran

Traditionally dynamic analysis is done using Newton’s universal laws of the equation of motion. According to the laws of Newtonian mechanics, the x, y, z, space-time coordinate system does not include a term for energy loss, an empirical damping term “C” is used in the dynamic equilibrium equation. Energy loss in any system is governed by the laws of thermodynamics. Unified Mechanics Theory (UMT) unifies the universal laws of motion of Newton and the laws of thermodynamics at ab-initio level. As a result, the energy loss [entropy generation] is automatically included in the laws of the Unified Mechanics Theory (UMT). Using unified mechanics theory, the dynamic equilibrium equation is derived and presented. One-dimensional free vibration analysis with frictional dissipation is used to compare the results of the proposed model with that of a Newtonian mechanics equation. For the proposed entropy generation equation in the system, the trend of predictions is comparable with the reported experimental results and Newtonian mechanics-based predictions.


1978 ◽  
Vol 10 (1) ◽  
pp. 43-49 ◽  
Author(s):  
D S Dendrinos

Some basic elements of catastrophe theory are discussed insofar as they relate to discontinuities observed in the allocation of economic activities in urban settings. The case of a dynamic model of the allocation of manufacturing and residential activities is presented in an open urban area as a model of a hyperbolic umbilic catastrophe. The dynamic equilibrium allocations of these two activities are identified as possible paths in the bifurcation set of the three parameter (control variables) and two behavioral-variables catastrophe type. A regulating function governing the urban system at the macroscale is discussed.


Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2638
Author(s):  
Xianhua Chen ◽  
Xingkai Yang ◽  
Ming J. Zuo ◽  
Zhigang Tian

Planetary gearbox systems are critical mechanical components in heavy machinery such as wind turbines. They may suffer from various failure modes, due to the harsh working environment. Dynamic modeling is a useful method to support early fault detection for enhancing reliability and reducing maintenance costs. However, reported studies have not considered the sun gear tooth crack and bearing clearance simultaneously to analyze their combined effect on vibration characteristics of planetary gearboxes. In this paper, a dynamic model is developed for planetary gearboxes considering the clearance of planet gear, sun gear, and carrier bearings, as well as sun gear tooth crack levels. Bearing forces are calculated considering bearing clearance, and the dynamic model equations are updated accordingly. The results reveal that the combination of bearing clearances can affect the vibration response with sun gear tooth crack by increasing the kurtosis. It is found that the effect of planet gear bearing clearance is very small, while the sun gear and carrier bearing clearance has clear impact on the vibration responses. These findings suggest that the incorporation of bearing clearance is important for planetary gearbox dynamic modeling.


2008 ◽  
Vol 381-382 ◽  
pp. 439-442
Author(s):  
Qi Wang ◽  
Zhi Gang Feng ◽  
K. Shida

Least squares support vector machine (LS-SVM) combined with niche genetic algorithm (NGA) are proposed for nonlinear sensor dynamic modeling. Compared with neural networks, the LS-SVM can overcome the shortcomings of local minima and over fitting, and has higher generalization performance. The sharing function based niche genetic algorithm is used to select the LS-SVM parameters automatically. The effectiveness and reliability of this method are demonstrated in two examples. The results show that this approach can escape from the blindness of man-made choice of LS-SVM parameters. It is still effective even if the sensor dynamic model is highly nonlinear.


2010 ◽  
Vol 156-157 ◽  
pp. 332-338
Author(s):  
Yuan Zhang ◽  
Kai Fu Zhang ◽  
Jian Feng Yu ◽  
Lei Zhao

To study the effect of assembly process information combining disassemble and assemble on satellite assembly sequence, this paper presents an object-oriented and assembly information integrated model, which is composed of static model and dynamic model. The feasibility determination based on Cut-set theory is presented and the construction algorithm of dynamic model is established by static model, the dynamic assembly model tree is obtained by analyzing in layers and verifying possible states using this algorithm, where the assembly model tree includes all the geometric feasible assembly sequences of satellite. Finally, this modeling method is verified by a satellite product.


2013 ◽  
Vol 475-476 ◽  
pp. 1551-1554
Author(s):  
Tie Nan Li ◽  
Shun Yu ◽  
Feng Yang

Almost all the fields use tree modeling in society, so it analyses the tree modeling in the academic circles. But it is difficult to find an efficient tree modeling method because its own complexity and wind, rain acting on tree. The object suffers rain power that the force calculated by momentum theorem. And then compare the value of rupture limit to Young modulus. It is determined object to fracture or sway. Then it constructs tree dynamic modeling in the nature.


2011 ◽  
Vol 199-200 ◽  
pp. 19-24
Author(s):  
Jin Fu Zhang

In order to investigate dynamic performance of flexible multi-link manipulators more exactly, establishing the dynamic model with accounting for link foreshortening and link material damping is needed. In this paper, a new dynamic model for planar flexible multi-link manipulators is established by using Lagrange approach. Both link foreshortening and link material damping are accounted for in this model. As a case simulation, this model is applied to a planar flexible two-link manipulator with a tip mass, and the motion responses of the manipulator are obtained using Gear method.


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