Research and Design of In-Arm Torsional Electromagnetic Active Suspension

2019 ◽  
Author(s):  
Chengleng Han ◽  
Lin Xu ◽  
Mohamed A. A. Abdelkareem ◽  
Enkang Cui ◽  
Junyi Zou ◽  
...  
Keyword(s):  
Characteristic Curve ◽  
Body Height ◽  
Active Suspension ◽  
Small Scale ◽  
Unknown Parameters ◽  
Body Attitude ◽  
New Type ◽  
Stiffness And Damping ◽  
The Mathematical Model ◽  
Research And Design

Abstract This paper introduced a new type of an active suspension named as In-Arm Torsional Electromagnetic Active Suspension (ITEAS) according to its suspension characteristics. The proposed ITEAS is capable of actively controlling body attitude and adjusting the stiffness and damping of a suspension system in a larger scale. The structure of the ITEAS system is composing of a mechanical displacement adjustment device, a two-chamber vane damper connected by an electromagnetic valve, two torsion bars and necessary connection units such as trailing arms. Based on the hydraulic theory and fluid mechanics, the mathematical model of the vane damper was established and the external characteristic curve of the damper was obtained through the simulations. Regarding to the ITEAS stiffness and damping analysis, a quarter dynamic vehicle model was established and simulated by the AMESim platform. The results showed that the automobile ride based on the ITEAS system was reasonable as well as the functions of body height adjustment and suspension controllability were available. Thereafter, a small-scale prototype has been built to calibrate the unknown parameters for further research on ITEAS.

Study on the working state of the five hundred-meter aperture spherical telescope using step-wise assignment method

2014 ◽  
Vol 229 (2) ◽  
pp. 316-324 ◽  
Author(s):  
Yu Liu ◽  
Feng Gao
Keyword(s):  
Nonlinear Equations ◽  
Analytical Solutions ◽  
Driving Mechanism ◽  
Initial Value ◽  
Unknown Parameters ◽  
Support Structure ◽  
Assignment Method ◽  
New Type ◽  
Set Up ◽  
The Mathematical Model

The working state of the five hundred-meter aperture spherical telescope (FAST) is solved using the step-wise assignment method. In this paper, the mathematical model of the cable-net support structure of the FAST is set up by the catenary equation. There are a large number of nonlinear equations and unknown parameters of the model. The nonlinear equations are solved by using the step-wise assignment method. The method is using the analytical solutions of the cable-net equations of one working state as the initial value for the next working state, from which the analytical solutions of the nonlinear equations of the cable-net for each working state of the FAST and the tension and length of each driving cable can be obtained. The suggested algorithm is quite practically well suited to study the working state of the cable-net structures of the FAST. Also, the working state analysis result of the cable-net support structure of a reduced model of the cable-net structure reflector for the FAST is given to verify the reliability of the method. In order to show the validity of the method, comparisons with another algorithm to set the initial value are presented. This method has an important guiding significance to the further study on the control of the new type of flexible cable driving mechanism, especially the FAST.

Research on Vibration Model of Special Vehicle Based on Dual-Mass System

2013 ◽  
Vol 385-386 ◽  
pp. 89-92 ◽  
Author(s):  
Ya Jun Shao ◽  
Qin He Gao ◽  
Hong Jie Cheng
Keyword(s):  
Characteristic Curve ◽  
Suspension System ◽  
Mass System ◽  
Nonlinear Characteristics ◽  
Actual Structure ◽  
Vibration Model ◽  
Special Vehicle ◽  
Set Up ◽  
Stiffness And Damping ◽  
The Mathematical Model

Taking a special vehicle vibration system as the research object, according to the actual structure of the chassis, the spring damping and stiffness of the nonlinear characteristics and the tire vertical elastic accounted, a nonlinear vibration model of special vehicle based on dual-mass-system is set up. The tire radial stiffness value is analyzed in Ansys, a simulation is performed by leading the mathematical model of suspension system into Adams, a characteristic curve of stiffness and damping of suspension system is obtained.

The research and verification of In-Arm Torsional Electromagnetic Active Suspension

2020 ◽  
pp. 095440702096528
Author(s):  
Chengleng Han ◽  
Lin Xu ◽  
Junyi Zou ◽  
Mohamed AA Abdelkareem ◽  
Enkang Cui
Keyword(s):  
Body Height ◽  
Simulation Models ◽  
Active Suspension ◽  
The Body ◽  
Theoretical Principle ◽  
The Road ◽  
New Type ◽  
Critical Components ◽  
Vehicle Suspension System ◽  
And Control

This paper designs and manufactures a new type of arm suspension institution named In-Arm Torsional Electromagnetic Active Suspension (ITEAS) according to the structure and characteristic. The paper introduces the function and application scenarios of ITEAS and narrates the research value and scientific significance of the system. At first, the structure and principle of ITEAS are presented briefly, based on which the mathematical model of ITEAS suspension and height adjustment is built and analyzed. Next, the paper studies three critical components of ITEAS respectively. The mathematical solution is found to calculate the stiffness of the torsion bar. The structure and hydrodynamic model of the vane damper is researched, and the simulation model of the absorber is built in AMESim. The paper studies the theoretical principle of height adjustment and obtains the frequency characteristic of “Motor-Load” through the transfer function solved in MATLAB. Therefore, simulation models are built in AMESim in allusion to the three functions in the next chapter to verify the suspension characteristic, the height adjustment and the active displacement control of ITEAS independently. At last, several experiments are conducted on the test bench to check the feasibility of ITEAS. The results show that ITEAS is capable of being used as a vehicle suspension system and has a good impact on mitigation ability under road surface excitation, which enables us to adjust the body height and control the displacement actively according to the road condition.

scholarly journals Single Epoch Ambiguity Resolution of Small-Scale CORS with Multi-Frequency GNSS

2021 ◽  
Vol 14 (1) ◽  
pp. 13
Author(s):  
Shengyue Ji ◽  
Qianli Zheng ◽  
Duojie Weng ◽  
Wu Chen ◽  
Zhenjie Wang ◽  
...  
Keyword(s):  
Ambiguity Resolution ◽  
Geographic Area ◽  
Satellite System ◽  
Small Scale ◽  
Full Potential ◽  
Unknown Parameters ◽  
Network Rtk ◽  
Single Epoch ◽  
Global Navigation Satellite ◽  
The Mathematical Model

The network real-time kinematic (RTK) technique uses continuously operating reference stations (CORS) within a geographic area to model the distance dependent errors, allowing users in the area to solve ambiguities. A key step in network RTK is to fix ambiguities between multiple reference stations. When a new satellite rises or when maintenance happens, many unknown parameters are involved in the mathematical model, and traditional methods take some time to estimate the integer ambiguities reliably. The purpose of this study is the single-epoch ambiguity resolution on small-scale CORS network with inter-station distance of around 50 km. A new differencing scheme is developed to explore the full potential of multi-frequency Global Navigation Satellite System (GNSS). In this scheme, a differencing operation is formed between satellites with the closest mapping functions. With the new differencing scheme, tropospheric error can be mostly neglected after the correction, as well as the double-differencing operation. Numerical tests based on two baselines of 49 km and 35 km show that the success rate of ambiguity resolution can reach more than 90%. The single-epoch ambiguity resolution for reference stations brings many benefits to the network RTK service, for example, the instantaneous recovery after maintenance or when a new satellite rises.

A simplified method for fault detection and identification of mismatch modules and strings in a grid-tied solar photovoltaic system

2020 ◽  
Vol 21 (4) ◽  
Author(s):  
Namani Rakesh ◽  
Sanchari Banerjee ◽  
Senthilkumar Subramaniam ◽  
Natarajan Babu
Keyword(s):  
Characteristic Curve ◽  
Dynamic Change ◽  
Photovoltaic System ◽  
Small Scale ◽  
Pv System ◽  
Pv Array ◽  
Detection And Identification ◽  
Fault Detection And Identification ◽  
Theoretical Predictions ◽  
Solar Photovoltaic System

AbstractThe foremost problem facing by the photovoltaic (PV) system is to identify the faults and partial shade conditions. Further, the power loss can be avoided by knowing the number of faulty modules and strings. Hence, to attend these problems, a new method is proposed to differentiate the faults and partially shaded conditions along with the number of mismatch modules and strings for a dynamic change in irradiation. The proposed method has developed in two main steps based on a simple observation from the Current versus Voltage (I-V) characteristic curve of PV array at Line-Line (LL) fault. First, the type of fault is detected using defined variables, which are continuously updated from PV array voltage, current, and irradiation. Second, it gives the number of mismatch modules (or short-circuited bypass diodes) and mismatch strings (or open-circuited blocking diodes) by comparing with the theoretical predictions from the I-V characteristic curve of PV array. The proposed algorithm has been validated both on experimentation using small scale grid-connected PV array developed in the laboratory as well as MATLAB/Simulink simulations. Further, the comparative assessment with existing methods is presented with various performance indices to show the effectiveness of the proposed algorithm.

Identification of Viscously Damped Distributed Structural Dynamic Systems

1991 ◽  
Author(s):  
R. Chander ◽  
M. Meyyappa ◽  
S. Hanagud
Keyword(s):  
Dynamic Systems ◽  
Beam Theory ◽  
Continuous Functions ◽  
Model Parameters ◽  
Unknown Parameters ◽  
Structural Dynamic ◽  
Domain Identification ◽  
Forcing Function ◽  
Cardinal Splines ◽  
Stiffness And Damping

Abstract A frequency domain identification technique applicable to damped distributed structural dynamic systems is presented. The technique is developed for beams whose behavior can be modeled using the Euler-Bernoulli beam theory. External damping of the system is included by means of a linear viscous damping model. Parameters to be identified, mass, stiffness and damping distributions are assumed to be continuous functions over the beam. The response at a discrete number of points along the length of the beam for a given forcing function is used as the data for identification. The identification scheme involves approximating the infinite dimensional response and parameter spaces by using quintic B-splines and cubic cardinal splines, respectively. A Galerkin type weighted residual procedure, in conjunction with the least squares technique, is employed to determine the unknown parameters. Numerically simulated response data for an applied impulse load are utilized to validate the developed technique. Estimated values for the mass, stiffness and damping distributions are discussed.

Deep and Shallow Water Low-Speed Maneuvering Tests: Comparison Between Experimental and Simulation Results

2016 ◽  
Author(s):  
Felipe Ribolla Masetti ◽  
Pedro Cardozo de Mello ◽  
Guilherme F. Rosetti ◽  
Eduardo A. Tannuri
Keyword(s):  
Mathematical Model ◽  
Small Scale ◽  
Shallow Waters ◽  
Hydrodynamic Coefficients ◽  
Low Speed ◽  
Tunnel Model ◽  
Oceanographic Research ◽  
Simulation Results ◽  
The University ◽  
The Mathematical Model

This paper presents small-scale low-speed maneuvering tests with an oceanographic research vessel and the comparison with mathematical model using the real time maneuvering simulator developed by the University of São Paulo (USP). The tests are intended to verify the behavior of the vessel and the mathematical model under transient and low speed tests. The small-scale tests were conducted in deep and shallow waters, with a depth-draft ratio equal to 1.28, in order to verify the simulator ability to represent the vessel maneuverability on both depth conditions. The hydrodynamic coefficients used in the simulator model were obtained by CFD calculations and wind tunnel model tests carried out for this vessel. Standard turning circle and accelerating turn maneuvers were used to compare the experimental and numerical results. A fair agreement was achieved for shallow and deep water. Some differences were observed mainly in the initial phase of the accelerating turn test.

scholarly journals The Vibration of Simply Supported Non-Uniform Cross Sectional Pipe Conveying Fluid Resting on Viscoelastic Foundation

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Natural Frequencies ◽  
Flexural Vibration ◽  
Bernoulli Model ◽  
Viscoelastic Foundation ◽  
Cross Sectional ◽  
Flowing Fluid ◽  
Simply Supported ◽  
Critical Velocities ◽  
Stiffness And Damping ◽  
The Mathematical Model

The induced flexural vibration of slender pipe systems with continuous non uniform cross sectional area containing laminar flowing fluid lying on extended Winkler viscoelastic foundation is considered. The Euler Bernoulli model of the pipe has hinged ends. The inlet flow is considered constant steady that interacts with the wall of the pipe. The mathematical model is developed and its corresponding solution is obtained. The influence of the combination of variation of cross section, foundation stiffness and damping on the critical velocities, complex natural frequencies and stabilization of the system is presented.

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