Suspension Frame Research Articles

Dynamic Interaction Analysis of a Coupled System of Permanent Maglev Train and Flexible Track Beam

Vehicle–track beam coupling resonance greatly influences the vibration response of the suspended permanent (SPML) system. Therefore, the study established the coupled dynamic model of the SPML train and the track beam using. The model is used to analyze the dynamic response of SPML trains when passing through the long-span flexible track beam at resonance speed. The accuracy of the model was verified by field tests, which simulated and compared the dynamic responses of maglev train and track beam systems at different running speeds. Furthermore, the coupled vibration response of the train and track beam at resonant speed are investigated to gain insight into the mechanism and vibrational properties of the SPML system in a resonant background. It shows that the dominant frequency of the train, suspension frame, and track beam is 6.74[Formula: see text]Hz. They result in resonance in the SPML system at 30[Formula: see text]km/h. Further analysis shows that adjusting the vertical distance between the mass center of the vehicle and the track beam can effectively alleviate the resonance between the vehicle and the track. Additionally, deformation at the ends of the long-span track beams affects the levitation force and gap of the suspension frame, offering valuable guidance for SPML system design.

Comparative analysis of seismic isolation effects under three-way seismic actions for suspension core-tube structure and frame core-tube structure

In this paper, the suspension core-tube structure and frame core-tube structure are taken as the research objects, and the modal analysis of them and their basic seismic isolation structures are carried out firstly to explore the self-vibration characteristics and seismic isolation effect of the structures. Secondly, the nonlinear time-history analysis of the four structures under the action of rare earthquakes in the X, Y, and Z directions is carried out, and their inter-story drift angles, inter-story shear forces, base shear forces, maximum accelerations at the apex of the core-tube, and cantilever beam stresses are analyzed comparatively. Finally, the displacements and loads of the energy dissipators, the maximum horizontal displacements and tensile and compressive stresses of the seismic isolation bearings are analyzed to evaluate the performance of both of them under rare earthquakes. The results show that the suspension core-tube structure and the frame core-tube structure with base seismic isolation bearings can provide good control of their inter-story drift angles and internal forces, etc. The suspension core-tube structure is superior to the frame core-tube structure in controlling the maximum acceleration at the apex of the core tube response.

Permanent Magnet Electrodynamic Suspension System Integrated With a Car: Design, Implementation, and Test

In this paper, a permanent magnet electrodynamic suspension (PMEDS) system integrated with a car has been developed by our group, along with a 100-m-long test track made of copper. The entire vehicle weighs 2.8 ton and is freely suspended in air over 35 mm without a lateral constraint on guideway. The car uses its own wheels and engine to provide a take-off speed for the PMEDS system, eliminating the excessive costs of the motor, with a maximum speed of 70 km/h. Firstly, a new topology structure equipped with the damping magnets is presented. Afterward, the onboard magnets and guideway are designed via the simulation method verified by the high-speed rotary experiment platform with a diameter of 2500 mm, clarifying the mapping between the electromagnetic forces and structure parameters. The suspension frame and gap adjustment mechanism are developed, and a complete test system is built to monitor the levitation gap, accelerations and deflection angle. Lastly, the integrated PMEDS system is implemented and tested. In-house experiment and line test results not only reveal that the PMEDS has a significant weak guidance capability, but also confirm the effectiveness of the proposed damping magnets. Through the damping magnets, the maximum lateral deflection is limited to less than 11°. The tested levitation-drag-ratio is in general agreement with the simulation results. The great suspension capacity of the PMEDS system can be visually demonstrated. This paper conducts the free suspension test of the PMEDS system for the first time in China, which can open up prospects for further engineering applications.

Nonlinear Vibration and Stiffness Characteristics Analysis of Maglev Train Based on Cubic Displacement Control

A control strategy combining cubic displacement feedback nonlinear control and proportional-differential (PD) linear control is used to control the vibration performance of the maglev system. The maglev system is divided into positive stiffness maglev system, quasi-zero stiffness maglev system and negative stiffness maglev system according to the linear stiffness value of maglev system. Firstly, an improved multi-scale method is used to analyze the vibration characteristics of suspension in the positive stiffness state of the maglev system. Secondly, the influence of control parameters on train vibration amplitude and vibration center displacement under quasi-zero stiffness is studied. Finally, the vibration characteristics of the train when the maglev system is in negative stiffness are analyzed by numerical simulation. The maglev system exhibits the worst vibration performance under negative stiffness compared with positive stiffness and quasi-zero stiffness. The suspension frame is easy to enter the chaotic motion state, and its vibration center is easy to deviate from the equilibrium position and produce large displacement when the maglev system is in the negative stiffness state. The control results show that the control strategy combining the cubic displacement feedback nonlinear control with the PD linear control can make the maglev system exhibit better vibration characteristics under positive and quasi-zero stiffness.

BIKE E-CATALOUGE

Abstract— An augmented reality mobile app that suggests features for a bike where customers can view details about the characteristics and technologies of the bike in front by scanning the QR code from a mobile app. The app ought to be able to display the most crucial elements on the screen. such as a strong engine Electronically Chic Front lights Diamond-Style Suspension Frame Prolonged, etc. This application focuses on addressing the inconvenience of customer to visit the physical store, providing users with a seamless and immersive platform where they can virtually inspect, customize, and experience bikes in detail, facilitating informed purchase decisions without the need for in- person visits to brick-and-mortar stores. Keywords— E-Catalogue, QR Scan, Augmented Reality, 3D Visualization, User Experience (UX)

Parameter optimization of electromagnetic suspension-type maglev train control system based on multi-objective grey wolf non-dominated sorting hybrid algorithm-Ⅱ hybrid algorithm

This paper presents a novel hybrid algorithm based on CMOGWO-ADNSGA-II to solve the vibration stability problem during the operation of a EMS-type maglev train dynamics model subjected to strong non-linear magnetic buoyancy. The proposed algorithm optimizes the control system parameters of EMS-type maglev train suspensions by combining an improved multi-objective chaotic grey wolf algorithm (CMOGWO) with an improved non-dominated Sorting genetic algorithm-II (ADNSGA-II) to enhance the search capability of the algorithm and ensure population diversity. The efficacy of the algorithm is demonstrated by applying it to the EMS-type maglev train suspension frame control system to find the optimal control parameters. Experimental results show that the system with the optimal parameters applied significantly reduces the suspension gap amplitude and the corresponding standard deviation, as well as the vertical acceleration amplitude and the corresponding standard deviation during operation. The proposed algorithm provides a good solution for EMS-type maglev train suspension vibration control, which can improve its performance and safety.

A Fuzzy-Logic-System-Based Cooperative Control for the Multielectromagnets Suspension System of Maglev Trains With Experimental Verification

A maglev train is a sustainable public transport method with the characteristics of being green, pollution-free, and low-noise, as well as providing environmental protection. However, the performance of existing maglev control strategies for maglev trains may be deteriorated by various challenges, including disregard of the coordination and synchronization between multiple electromagnets, control input unidirectionality, dead zones, saturation, and finite time stability ability, etc. In this paper, an adaptive fuzzy-based suspension control method based on a multi-electromagnets dynamic coupling model is proposed that can cope with dead zone and saturation problems and guarantee the finite-time of the airgap tracking errors of multiple electromagnets simultaneously. Specifically, a fuzzy-logic system (FLS) is utilized to compensate for the nonlinear input unidirectionality, dead zone, saturation and unmodeled dynamics. Moreover, considering the coupling dynamic characteristics of adjacent electromagnet control modules, a fuzzy-based cooperative suspension controller with adaptive update law is designed. The finite time stability of the presented control strategy is proven with the Lyapunov method. Finally, the suspension frame experimental results are illustrated to validate the effectiveness and robustness of the developed method, whose superior performance is shown by being experimentally compared with some baseline methods.

Operation Control Method for High-Speed Maglev Based on Fractional-Order Sliding Mode Adaptive and Diagonal Recurrent Neural Network

The speed profile tracking calculation of high-speed maglev trains is mainly affected by running resistance. In order to reduce the adverse effects and improve tracking accuracy, this paper presents a maglev train operation control method based on a fractional-order sliding mode adaptive and diagonal recurrent neural network (FSMA-DRNN). First, the kinematic resistance equation is established due to the three types of resistance that occur during the actual operation of a train: air resistance, guide eddy current resistance, and suspension frame generator coil resistance. Then, the FSMA-DRNN control law and parameter update law are designed, and a FSMA-DRNN operation controller is composed of three parts: speed feed forward, fractional-order sliding mode adaptive equivalent control, and diagonal recurrent neural network resistance compensation. Furthermore, by using the designed operation controller, it is proven effective by the Lyapunov theory for the stability of the closed-loop control system. Apart from the proposed theoretical analysis, the proposed approaches are verified by experiments on the high-speed maglev hardware-in-the-loop simulation platform Rt-Lab, in line with the 29.86 km test line and a five-car train from the Shanghai maglev, showing the effectiveness and superiority for operation optimization.

Simulation Analysis and Online Monitoring of Suspension Frame of Maglev Train

A maglev train is a new type of high-speed railway transportation. A high-temperature superconducting (HTS) maglev system is one of the typical representatives in the field of maglev trains. In order to research the levitation characteristics of an HTS maglev train, the force characteristics and operation performance of the train were researched. However, at present, there is still no research that simulates the real load situation of a running maglev train while analyzing the suspension frame. Regarding this issue, in this paper, the suspension frame is simulated and analyzed to simulate the real load situation of a maglev train. The results show that the suspension frame of an HTS maglev train can bear corresponding loads under different working conditions, and its strength and stiffness meet the requirements of use, safety, and reliability. Random irregularity in the permanent magnet track of an HTS maglev train route is inevitable, which will make the suspension frame produce a vibration response under different running speeds of the train. Vibration of the suspension frame of the train is inevitable. For the electromagnetic levitation (EMS) train, researchers considered monitoring the train status. However, at present, there is no suspension frame condition monitoring device for an HTS maglev train. In addition, the levitation height of the suspension frame affects the suspension performance and traction performance of the vehicle, and the vibration of the suspension frame during running affects the dynamic performance and safety of the suspension frame and the vehicle. Regarding the issue above, through a suspension frame monitoring system, the lateral and vertical vibration acceleration and levitation height of the suspension frame are monitored at different train speeds. The maximum value of vibration acceleration and the fluctuation range of levitation height are within the safe range. It is verified that the simulation analysis of the suspension frame of an HTS maglev train is correct, the suspension frame is safe, and the train can run safely.

Field Measurements and Analyses of Traction Motor Noise of Medium and Low Speed Maglev Train

In order to reduce the impact of noise on the environment and reduce the dissipation of useless energy of traction motors, this study analyzed the noise of a traction motor by detecting the vibration acceleration of the suspension frame. Field tests were conducted to measure the traction noise and suspension frame vibration in a commercially operational medium- and low-speed maglev train. The tests showed that as the train accelerates, the sound pressure grows overall, but the increase becomes smaller at each test speed. The speed of the maglev train is closely correlated with the vibrations of the suspension frame in lateral/vertical directions. The dominant frequency of traction motor noise is basically consistent with that of suspension frame vibration acceleration, showing that the suspension frame vibration is the main reason for high-frequency noise in the operation of low–medium-speed maglev trains.

Field experimental tests and analyses of suspension frame vibration of low-medium speed maglev train

Pushed by social demands, China has continuously developed its low-medium speed maglev transportation systems in recent decades. However, with the increase of the running mileage of the train, high frequency vibration of suspension frame gradually appears. In this paper, a method to analyze the high frequency vibration of suspension frame by detecting the current of traction motor is proposed. Field measurements of suspension frame vibration and traction motor current of low-medium maglev train were conducted on a maglev line that has been commercially put into operation. The test results show that the speed of the measured maglev train was closely correlated with vibration accelerations of the suspension frame in three directions, but as the speed increased, the influence it imposed on the suspension frame vibration waned. The dominant frequency of traction motor resultant current was consistent with the dominant frequency of the suspension frame vibration acceleration. The switching frequency of traction inverter was the main cause of high frequency vibration of suspension frame.

Field Tests and Analyses on Running Stability of Fenghuang Medium and Low Speed Maglev Train

Multiple field tests were carried out on the Fenghuang medium and low speed maglev train. During the tests, the authors collected the vibration data of train carriage and suspension frames under no-load (AW0). Next, the stability of the maglev train under corresponding conditions was investigated, using indices like weighted RMS acceleration (ISO 2631) and Sperling index. Through the in-depth analyses, it was concluded that the maglev train runs smoothly, and the passengers on the train generally feel comfortable.

Strength analysis and optimization of three-bridge rigid frame for mining dump truck using finite element stress linearization method

A finite element stress linearization method is introduced into the structural verification of the three-bridge rigid frame, a newly designed frame for the wide-body mining dump truck. This method successfully captures the potential local failure around the structural-discontinuity zone. The results indicate that the suspension supports experience high-level stress under six operating conditions and the most dangerous location of the frame always lies at the weld bead between the suspension support and frame. The stress intensities of the original frame under six operating conditions are all smaller than the allowable value, manifesting that the strength of the original frame can meet the strength requirements. The local modifications greatly reduce the local stress and thus improve the reliability of the frame, manifested by the reduced stress level and stress intensity along dangerous paths. The primary plus secondary stress intensity along the most dangerous path decreases by 16.69% under the condition of free-hanging left front wheel, and by 59.91% under the condition of free-hanging right rear wheel. The present work provides a sound method to evaluate the local failure of the frame for the mining dump truck containing many structural-discontinuity zones, and the result is helpful for the continuous improvement of the frame for the wide-body mining dump truck and provides a guideline for designing a new frame.

Vibration Characteristics of HTS Maglev System Levitated Above a Halbach Permanent Magnet Track

As a novel type of rail transit system, high temperature super-conducting (HTS) magnetic levitation (maglev) has entered the research and development stage of engineering application. Dur-ing the future practical engineering, the dynamics performance of HTS maglev system is very important. Because its vibration char-acteristics will affect the safety and comfort of vehicle operation. Although, lots of previous experimental studies have shown that the HTS maglev system is laterally-vertically coupled, the related researches are not sufficient. This lack of lateral-vertical coupling model will make it very difficult to analyze the vibration charac-teristics of HTS maglev system in a practical operation condition. Therefore, a lateral-vertical coupling dynamic model is estab-lished in this paper, and the response of the maglev system under forced vibration is analyzed. Firstly, we use a scaled-down sus-pension frame to carry out the free vibration experiment of the maglev system. Secondly, based on a mathematical model of two-dimensional force, a damping term is added to reflect the hystere-sis, so as to establish a lateral-vertical coupling dynamic model. After comparing the simulation results of the dynamic model with the experimental results, the accuracy of the dynamic model is verified. Finally, this dynamic model is used to simulate the forced vibration of the maglev system, and the lateral-vertical coupling vibration characteristics of the maglev system under dif-ferent working conditions are studied. Results show that the lat-eral-vertical coupling effect of the maglev system is significant, and the coupling vibration has strong nonlinear characteristics. This study is expected to provide relevant reference basis for the engineering application of HTS maglev.

Vertical Dynamic Response of the 2-DOF Maglev System considering Suspension Nonlinearity

In order to study the dynamic characteristics of the nonlinear system of the maglev train, a vibration model of the two-degree-of-freedom nonlinear suspension system of the maglev train is established in this paper. Based on the linearized model of the suspension control module, the suspension system is controlled by the state feedback method. Compared with the results of the Runge–Kutta method, the accuracy of the settlement results is verified. This paper analyzes the influence of system parameters and feedback control parameters on the system. The results show that the linear stiffness mainly affects the left-right migration of the resonance peak and the difference between the maximum and minimum of the resonance region of the suspension frame; the nonlinear stiffness mainly affects the slope of the resonance region of the car body and the suspension frame; displacement feedback control parameters can reduce the amplitude of the system, velocity feedback control parameters can make the state change of the suspension frame more smoothly, and acceleration feedback control parameters make the car body and the suspension frame have a strong coupling effect. According to the Hurwitz criterion of Hopf bifurcation, this paper deduces the conditions that the control parameters should satisfy when the equilibrium point is stable, and the instability produces periodic vibration under PID control. Through numerical simulation, it is found that the system has complex dynamic behavior, the results show that the system works under some conditions, and there are multiple stable and unstable limit cycles simultaneously. Therefore, the system will appear alternately between multiperiod and chaotic motion, which will affect the stability of the system.

Reconfiguration of a Bus Chassis Module Using the Digital Expression for Connectivity between Module Interfaces

Modular design for a bus chassis is a practical solution to address different bus types and their differing powertrains. Physics interfaces are used to connect interacting subsystems in bus chassis modules. There are few studies focusing on the criteria for assessing interface connectivity, with significantly non-standard characteristics, between bus chassis modules. This study proposes criteria for assessing the interface connectivity in bus chassis modules in accordance with the digital expression of the module interface. Criteria for judging the compatibility of the connection between bus chassis modules are proposed and modular reconfiguration methods are provided, based on the criteria. Reconfiguration of the process matrix is constructed to indicate changes in position, shape, and size after the component is modified, based on the connectivity between modules. Finally, the proposed method is applied to the reconfiguration and replacement of the front suspension frame module of a bus chassis. The results demonstrated and proved the effectiveness of this method.

ELECTRIC GENERATOR POWERED BY A GYROSCOPIC SYSTEM - A THEORETICAL APPROACH

The development of our society now depends on electrical energy and the demand for electrical power increases yearly. Due to the vast amount of carbon dioxide released in the atmosphere by conventional power plants and the negative influence on the climate, new ways of producing electricity must be developed. A gyroscope consists of a spinning flywheel of mass m mounted in a suspension frame that allows the flywheel’s axle to point in any direction. In this analysis, one end of the axle is supported by a pylon situated at a distance R from the center of mass of the spinning flywheel. In order to generate electrical energy at this low speed, the same approach should be used as in wind power electrical generators. In this case, the wind and propeller are substituted by a gyroscopic system and gravitational attraction. Based on the conservation of angular momentum, the gravitational attraction can be used to create a precession strong enough to provide the energy and torque necessary to activate an electric generator similar to those in wind power generators. Instead of recovering the energy from this kinetic energy, we can use the precession rotation created by gravitational attraction to create the necessary kinetic energy.

Ride and Comfort Measurements - A Challenge of Subjective and Objective Correlation

<div class="section abstract"><div class="htmlview paragraph">Traditionally, vehicle ride and comfort is evaluated, subjectively as well as objectively. Based on the outcome of subjective and objective tests, it is refined by optimizing primary suspension system, secondary suspension system, seating system, rubber bushings, frame and BIW for mass, stiffness, damping, geometry etc. Many a time subjective assessment results stands in contradiction to the objective assessment results; emphasizing need for having good correlation between subjective and objective test results. In such cases, it is ambiguous to decide suitable design refinement action and can lead to no improvement situation. Hence, it is essential to have concurring test procedures for subjective and objective ride evaluation. This paper describes a novel methodology to address the above said challenge. There are defined set of test events and measurement data points to be used in subjective and objective testing. The subjective assessment is performed using clearly defined goals for what to look for and how to look for different ride and comfort attributes and sub attributes. Similarly for objective test, accelerations, displacements and loads are measured at defined locations on vehicle application specific, various types of service roads for long enough duration, to have no or minimum impact of road inputs or events having high kurtosis value, on the objective ride measurement results. Measured data is post processed separately to arrive at objective ride index value for each of the subjective attribute i.e. bounce, pitch, roll, head toss, bobbing, choppy ride etc… For this, set of measured data is processed and analyzed for interested and relevant frequency ranges instead of limiting it to ISO 2631. This approach provides direct comparison of subjective rating number and objective ride index value for each of the attribute. This new approach has proven very useful in refining the vehicle ride and comfort by achieving 85~90% correlation between subjective and objective test results.</div></div>

Theoretical analysis and optimization of toggle-brace damper for cable tray system

The cable tray system, one type of non-structural components, may suffer severe damage and even fall in case of earthquakes, causing interruptions to post-earthquake operations and even injuries or casualties. This paper introduces a toggle-brace damper (TBD) into the cable tray system to control its seismic response and damage. However, owing to the large deformation/rotation effect in the TBD equipped cable tray system, the traditional design method based on small deformation assumption is no longer applicable. The new deformation calculations of suspension frame and TBD subjected to displacement loading are established combining the optimization technique and the geometry relationship, respectively. After then, an optimization design method for connecting location of the damper brace is proposed, considering the installation errors, deformation constraints, and loading process. With the aid of numerical analysis, it is found that the large deformation effect and in-plane installation errors have considerable influence on the damping magnification function. Compared with typical seismic resistant elements such as the steel brace, diagonal- and chevron-brace damper, the proposed optimal TBD can dissipate more energy and effectively suppress the vibration of cable tray system.

Design and Build of Electric Car Frame SULA Evolution

This research is research and development. The purpose of this research is to make an electric car design drawing according to the national electric car race standards that have better dimensions and turbulence than the previous design. The method in designing an electric car frame is by observing and studying the literature. The results of data collection are selected and reviewed and a design is made according to standards. Supervise and evaluate so that design and manufacture are not much different. The results obtained in the design are (1) The design results in the manufacture of the Sula evolution electric car frame, there are two parts, namely the mainframe and the suspension frame. The frame is divided into several parts, namely the seat holder, battery holder, controller holder, and rollbar. While the suspension frame is the front arm and rear arm; (2) In the design of the Sula evolution electric car frame, the calculations carried out are using the Autodesk Inventor application and the formula in analyzing the results of the mainframe design for the Sula Evolution electric car, namely the calculation of the weight of the material based on the data taken from the design drawings made.