The Influence of Payload Mass and Inertia Properties on a Piloted Flight Simulator Hexapod Dynamic Performance

2014 ◽  
Vol 1037 ◽  
pp. 61-65
Author(s):  
Chun Ping Pan ◽  
Ying Lu ◽  
Yi Jun Lin

In order to improve the dynamic performance of a piloted flight simulator hexapod, a study was carried out to quantify the effects of payload mass and inertia properties on hexapod dynamic performance. Based on the Lagrange-Euler formulation, a dynamics model of hexapod parallel mechanism including the payload mass characteristics was built, and then analyzed with the real hexapod through experiments. According to a large amount of experiment datum, the influence of payload mass and inertia properties on a piloted flight simulator hexapod dynamic performance was obtained, and these results are significant for the high speed and high acceleration control of the hexapod mechanism.

Author(s):  
Zhonghui Yin ◽  
Jiye Zhang ◽  
Haiying Lu ◽  
Weihua Zhang

Due to urbanisation and the economic challenges of traffic, it is urgently necessary to develop an environmentally friendly virtual-track train with suitable speed, high load capacity and low construction cost in China. To guide the design and evaluate this train’s dynamic behaviour, a spatial-dynamics model has been developed based on the dynamics theory and tyre-road interaction. The proposed dynamics model comprises mechanical vehicle systems, traction and braking characteristics and tyre-road dynamic interactions. The coupling effects amongst those systems of virtual track train are derived theoretically for the first time. The nonlinear characteristics of the tyre are modelled by the transit tyre-magic formula with consideration of road irregularities. Based on a designed PID controller and the comprehensive dynamics model, the dynamic performance of the system can be revealed considering motion coupling effects and complicated excitations, especially under traction and braking conditions. The dynamic responses of whole virtual track train can be obtained by numerical integration under different conditions. The vibration characteristics of such train are assessed under running at a constant speed and during the traction/braking process. The results show that the vibrations of the vehicle system are significantly influenced by road irregularities, especially at high speed ranges. The motions and vibrations of different components are intensive coupled, which should not to be neglected in the dynamics assessment of the virtual track train. Besides, the dynamics model can also be applied to dynamics-related assessment (fatigue, strength and some damage conditions, et al.) and parameter optimisation of the virtual-track train.


2010 ◽  
Vol 97-101 ◽  
pp. 3113-3119
Author(s):  
Ping Ma ◽  
Cheng Xiang Liao ◽  
Zhen Hui Chen ◽  
Gong Zhen

In high speed machining, the feed drives with high velocity and high acceleration are necessary to make full use of the capacities of the high speed motorized spindles. The linear motor feed drive eliminates any mid- transmitting mechanism, which cause achieved the high acceleration. In this paper, the GD-Ⅲ linear induction motor feed drive is introduced, and its controller is modeled and its stiffness has been investigated with simulation program MATLAB & SIMULINK. The influence of the parameters of the controller on the dynamic performance has also been analyzed. The simulation shows that the positional loop proportional gain kv, velocity proportional gain kp, velocity loop integral time constant Tn and the current loop proportional gain kpi have great influence on the dynamics of the linear motor feed drive. In the end, the simulation is verified by the experimental results.


Author(s):  
Zhiwei Wang ◽  
Guiming Mei ◽  
Weihua Zhang ◽  
Yao Cheng ◽  
Hangyu Zou ◽  
...  

This study investigates the effects of polygonal wear of wheels on the dynamic performance of the gearbox housing of high-speed trains. First, a dynamics model of the driving system is developed considering gear meshing and flexible deformation of the gearbox housing. Responses of the gearbox housing are calculated using the modal superposition method. Then, a multibody dynamics model of a railway motor car is established considering the driving system. Rig tests in the laboratory and field experiments on the Beijing–Shanghai high-speed rail line are, respectively, performed. Based on the simulation and experiments, the dynamic characteristics of the gearbox housing of the motor car are analysed. The results of the analysis show that polygonal wear can significantly influence the vibration of the gearbox housing, and the maximum amplitude of the acceleration of vibration is more than 200  g. In addition, resonance of the gearbox housing occurs due to the 20th-order polygonal wear. In the resonance region, the oil level sight glass of the gearbox housing vibrates severely, contributing immensely to its cracking.


2011 ◽  
Vol 311-313 ◽  
pp. 1398-1403
Author(s):  
Ying Cai Yuan ◽  
Yan Li ◽  
Yi Ming Wang

In high speed, the web press’s fold mechanism appears nonlinear dynamic response characteristics, which seriously affect the fold system’s stability and precision. The clearance and roller’s deformation are the main factors to cause the nonlinear dynamic response. To study the influence of clearance and roller’s deformation, the hypothesis of rigid role and spring combination is put forward. Based on the hypothesis, the dynamics model of fold system with clearance is established by kinematics and dynamics analysis. Through the dynamics model of fold system, the situation of pair clearance and roller’s deformation can be obtained, and the influence to the dynamic performance of fold system can be easily got.


2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Gengxiang Wang ◽  
Hongzhao Liu

Effects of flexible body and clearance spherical joint on the dynamic performance of 4-SPS/CU parallel mechanism are analyzed. The flexible moving platform is treated as thin plate based on absolute nodal coordinate formulation (ANCF). In order to formulate the parallel mechanism's constraint equations between the flexible body and the rigid body, the tangent frame is introduced to define the joint coordinate. One of the spherical joints between moving platform and kinematic chains is introduced into clearance. The normal and tangential contact forces are calculated based on Flores contact force model and modified Coulomb friction model. The dynamics model of parallel mechanism with clearance spherical joint and flexible moving platform is formulated based on equation of motion. Simulations show that the dynamic performance of parallel mechanism is not sensitive to the flexible body because of the inherent property of moving platform; however, when the clearance spherical joint is considered into the parallel mechanism with flexible body, the flexible moving platform exhibits cushioning effect to absorb the energy caused by clearance joint.


Author(s):  
Leonardo Urbiola-Soto ◽  
Marcelo Lopez-Parra ◽  
Francisco Cuenca-Jimenez

Among the solutions to the rotor unbalance problem, the previous art shows the use of passive balancers. The liquid balance ring fall in this category, which basically consists of a hollow ring equipped with a number of anti-sloshing baffle boards inside the cavity. The liquid contained within the ring adopts an antagonist position to the unbalance, thus balancing the rotor. Nowadays, in regard to the shape of the baffles boards employed in liquid balance ring devices, the use of straight baffles is the standard practice. However, as the fluid is subjected to rotation, it makes sense to believe that there should be a better baffle shape to enhance the fluid-solid interaction and improve the balance ring dynamic performance. This research work introduces for the first time a balance ring with curved (forward and backward) blades that remarkably enhance the unbalance response of rotors in the transient and steady-state. A classical dynamics model of this novel bladed concept is introduced and employed in designing a liquid balance ring for high-speed performance. Experimental data showing good correlation between the model and tests is presented.


2020 ◽  
Vol 13 (2) ◽  
pp. 126-140
Author(s):  
Jing Gan ◽  
Xiaobin Fan ◽  
Zeng Song ◽  
Mingyue Zhang ◽  
Bin Zhao

Background: The power performance of an electric vehicle is the basic parameter. Traditional test equipment, such as the expensive chassis dynamometer, not only increases the cost of testing but also makes it impossible to measure all the performance parameters of an electric vehicle. Objective: A set of convenient, efficient and sensitive power measurement system for electric vehicles is developed to obtain the real-time power changes of hub-motor vehicles under various operating conditions, and the dynamic performance parameters of hub-motor vehicles are obtained through the system. Methods: Firstly, a set of on-board power test system is developed by using virtual instrument (Lab- VIEW). This test system can obtain the power changes of hub-motor vehicles under various operating conditions in real-time and save data in real-time. Then, the driving resistance of hub-motor vehicles is analyzed, and the power performance of hub-motor vehicles is studied in depth. The power testing system is proposed to test the input power of both ends of the driving motor, and the chassis dynamometer is combined to test so that the output efficiency of the driving motor can be easily obtained without disassembly. Finally, this method is used to carry out the road test and obtain the vehicle dynamic performance parameters. Results: The real-time current, voltage and power, maximum power, acceleration time and maximum speed of the vehicle can be obtained accurately by using the power test system in the real road experiment. Conclusion: The maximum power required by the two motors reaches about 9KW, and it takes about 20 seconds to reach the maximum speed. The total power required to maintain the maximum speed is about 7.8kw, and the maximum speed is 62km/h. In this article, various patents have been discussed.


2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.


Author(s):  
Zhonghui Yin ◽  
Jiye Zhang ◽  
Haiying Lu

To solve the urbanization and the economic challenges, a virtual track train (VTT) transportation system has been proposed in China. To evaluate the dynamic behavior of the VTT, a spatial dynamics model has been developed that considers the suspension system and the steering system. Additionally, the model takes into account road irregularity to make simulations more realistic. Based on the newly proposed dynamic model and a designed proportional–integral–derivative (PID) controller, simulation frames of the vehicle and of the VTT are established with the path-tracking performance. The results show that the vehicle and the VTT can run along a desired lane with allowable errors, verifying the proposed model. The vehicle and VTT with the four-wheel steering system show a better dynamic performance than the models with the front-wheel steering system in the curved section. Moreover, the simulation frame can be further applied to dynamics-related assessments, parameter optimization and active suspension control strategy.


Cryogenics ◽  
2021 ◽  
pp. 103321
Author(s):  
Yuhang Yuan ◽  
Jipeng Li ◽  
Zigang Deng ◽  
Zhehao Liu ◽  
Dingding Wu ◽  
...  

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