Electric Wheel Research Articles

The Use of Integral Adaptation Principle to Synthesize Robust Control of Electric Vehicle Wheel Slip

The usage of "motor-wheel" systems requires the electric vehicle control system improvement by using the characteristics of the wheel adhesion to the road surface. One of the aspects of such improvement is the enhancement of the algorithms for the functioning of the antilock braking system (ABS). In developing the ABS control algorithms, various approaches and methods of modern control theory are used, including methods based on the estimation of wheel slip, traction force, wheel friction coefficient using linear and nonlinear estimation methods, linear and nonlinear regulators. This work illustrates the application of the principle of high order integral adaptation (PIA) of Synergetic Control Theory (SCT) for constructing a robust control law for an electric vehicle wheel slip. The main features of the SCT contain: firstly, a fundamental change in the goals of the behavior of the synthesized systems; secondly, direct consideration of the natural properties of nonlinear objects; thirdly, the formation of an analytical mechanism for generating feedbacks, i.e. control laws. PIA consists in introducing nonlinear integrators into the control law that compensate for disturbances without their immediate estimation. The obtained in this work control law has a fairly simple structure, is focused on using physically accessible state variables of the braking system, and its implementation does not require immediate estimation of disturbances or building a complex neural network to calculate disturbances. The results of computer simulations of the synthesized robust control law for ABS indicate its effectiveness in functioning under conditions of external environment uncertainty.

Estimating operation modes for the individual wheel electric drive of the all-wheel drive vehicle with the use of the driving simulator

With the development of the electric drive systems and vehicle on-board power sources the electric transport is becoming more popular, in particular wheeled vehicles with individually driven wheels, while the question of choosing power plants for this type of transport remains unresolved. In the presented article, the authors illustrate an approach to determining the requirements for power plants of such vehicles by an example of a four-wheel drive car equipped with an individual electric wheel drive. The approach is based on the use of the real-time driving simulator allowing the operator to drive the vehicle along typical routes. The typical routes for the driving simulator are generated from the known statistical data on the excitation inputs during the vehicle motion. Thus, the developed driving simulator provides analysis of the vehicle traction motors operation in the conditions most close to the actual ones and collection of the necessary statistical data which can be used for statement of the requirements for new electric machines which would provide their most effective use on the vehicle.

Influence Mechanism of Electromechanical Parameters on Transient Vibration of Electric Wheel System

<div class="section abstract"><div class="htmlview paragraph">Electric wheel systems of in-wheel motor driven vehicles consist of the motor controller, in-wheel motor and tire-suspension assembly. The coupling between the electromagnetic excitation and elastic structure gives rise to electromechanical dynamic issues. As for the structural layout of the electric wheel system, the driving motor is directly connected to the wheel without torsion dampers or transmission in the driveline, thus making the electric wheel structure a weak damping system. Moreover, the driving torque of electric wheel can change rapidly in various conditions of vehicle. As a result, the transient vibration problem becomes one of the key electromechanical dynamic issues in the electric wheel system. To investigate this problem, the electromechanical coupling model of the electric wheel system is established first. Then the transient responses of the electric wheel under abrupt changes of the driving torque are simulated. The results indicate that the tire mainly suffers from longitudinal shocks in the anti-phase rotational mode at 95 Hz and vibration in the in-phase rotational mode at 44Hz successively, while the motor vibrates in the in-phase rotational mode at 44Hz. As the electric wheel system is electromechanically coupled, the influence mechanism and rules of electromechanical parameters on the transient vibration are studied. The results show that the permanent magnet flux linkage increases damping ratio of the in-phase rotational mode in virtue of the electromagnetic stiffness and damping, thus further weakening transient vibration of motor. The anti-phase rotational mode is sensitive to tire’s stiffness. It is effective to optimize tire’s shock by adjusting tire’s stiffness. This paper reveals the electromechanical coupling mechanism of the electric wheel system, and provides reference for parameter design from the perspective of improvement in dynamic characteristics.</div></div>

A low cost solar powered vehicle – a boon for physically challenged persons

This paper presents a low cost solar powered vehicle for physically challenged persons. Generally, the persons with physical disabilities restrict their movement within a house or building due to their dependence on other people for their outdoor work. The disabled people use their limbs to drive the wheelchairs which physically stress them. There are electrical wheelchairs which are operated by hands, by mouth or any other functioning body part. The high cost and its limitation for outdoor environment restrict its usage for rich people and hospitals. This often makes the poor disabled person to be unemployed and depend on others for their daily life. In this regard, developing a low cost self-driven electric wheel chair can improve the life of the person. This paper presents a low cost vehicle for physically challenged people that can be used as a mobile shop to sell products at any place independently. The self-driven vehicle motivates the persons to become an entrepreneur. A cost effective and user friendly prototype has been developed for the benefit the poor disabled people and the cost analysis is presented. The purpose of developing the vehicle is satisfied as they no longer depend on others for their living. Implications for rehabilitationThe movement of physically challenged persons is often restricted within a building due to their dependence on other people for their outdoor work.The high cost of the assist vehicles and the difficulty encountered in using the vehicles in outdoor environment decreases their standard of living.The developed low cost vehicle can be used by physically challenged people as a mobile shop to sell products at any place independently.The self-driven vehicle motivates the physically challenged persons to become an entrepreneur.

Fuzzy fatigue reliability analysis and optimization of A-type frame of electric wheel dump truck based on response surface method

Due to many bends on the mine road surface, the electric wheel dump trucks turn frequently. The A-type frame is regarded as the key bearing component in the steering system for the electric wheel dump truck , while its fatigue reliability is one of the important factors to ensure truck’s running safety. In order to accurately evaluate fatigue reliability performances of A-type frame, a fuzzy fatigue reliability calculation method based on response surface method is proposed, considering the uncertainties of A-type frame in the actual manufacture and use stage. The material parameters of welding seam of A-type frame were obtained through experimental work. The load information of pivotal connection sites of A-type frame was obtained by the rigid and flexible coupling multi-body dynamics analysis for the whole vehicle. The finite element model of A-type frame with welding details was constructed, and its accuracy was verified by stress test on the mine road surface. Then, the material parameters and load information of A-type frame were taken as random variables and fatigue limit was regarded as a fuzzy variable. The random variables were sampled by Latin hypercube method, and the corresponding response values were obtained by the elastic and plastic finite element simulation under cyclic loadings. The fatigue reliability performance function of A-type frame was constructed based on response surface method. Finally, based on fuzzy theory, the fatigue reliability performance of A-type frame under the condition of downhill and turning braking with full load was evaluated, and its fatigue reliability was found to be less than 90%. Then, the fuzzy fatigue reliability performance was optimized by genetic algorithm. According to the optimized results, a new flexible front lateral stabilizer for this steering system was presented，which could improve the bearing capacity and force status of A-type frame and guarantee the fatigue reliability performance of A-type frame. The final fatigue reliability of the optimized A-type frame reached up to 98%. DOI: http://dx.doi.org/10.5755/j01.mech.25.1.21726

Design of a New Type of External Traction Device of Wheelchair based on STM32 Chip

Compared with manual wheelchair, electric wheelchairs are more suitable for long-distance walking. But the price of electric wheelchair is high and it is inconvenient to carry. In this paper, a new type of external traction device of wheelchair based on STM32 chip was designed, which was versatile, light weight and easy to carry. The traction device was mainly composed of car body, electric wheel, drive control system, electronic intelligent steering system, speed control system, pre-crash safety system and etc. It had a variety of functions and was easy to operate, providing excellent solutions for wheelchair users.

Measuring Point Selection Method of Vibration Signal of Electric Wheel Based on Compounded Distinguish Index

Measuring Point Selection Method of Vibration Signal of Electric Wheel Based on Compounded Distinguish Index

Dynamic Response Analysis for NW Planetary Gear Transmission Used in Electric Wheel Hub

Taking the NW planetary gear transmission of an electric wheel hub as the research object, the mesh model was developed to calculate the mesh parameters using Masta. Then the lump parameter method was used to establish the dynamic model of the NW planetary transmission system considering the time-varying mesh stiffness, transmission error and bearing stiffness. The impacts of the torque load on the dynamic characteristics including the dynamic mesh force, center trajectory, offsets and load sharing coefficients were investigated. Results show that the dynamic mesh force waveform and spectral characteristics of each planetary gear at high and low speeds under the rated and maximum torque load are almost identical. Compared to the peak response at speed 485 rpm and 1770 rpm, both the magnitude and location of the third response at relative high speed about 4300 rpm are increased due to the load increasing. The mean and fluctuation range of the offsets in the radial direction are both larger than the tangential direction. As the load increases, the mean value of the radial offset increases and the magnitude decreases significantly. The mean value of the tangential offset decreases significantly, but the magnitude increases first and then decreases. The load sharing characteristics of the low-speed stage of the NW planetary gear is better than the first stage. With the increase of the load, the load sharing performance of a two-stage planetary transmission gets better and the difference in load sharing between the high-speed and low-speed stages also decreases.

Model predictive speed planning for electric wheel chair considering interaction with pedestrians

Model predictive speed planning for electric wheel chair considering interaction with pedestrians

Coordinated motion and powertrain control of a series-parallel hybrid 8 × 8 vehicle with electric wheels

This article deals with the coordinated motion and powertrain control of a series-parallel hybrid 8 × 8 vehicle equipped with mechanical transmission and electric wheels. With six wheels driven by in-wheel motors and two driven by an AMT, the 8 × 8 vehicle has enormous potential to improve its dynamic performance, fuel economy, off-road mobility, maneuverability, gradeability, etc. On the other hand, as vehicle motion dynamics and powertrain components are closely coupled in the complex hybrid system, appropriate control strategy is urgently desired to deal with the torque distribution problem. Continuous control variables such as wheel torque, engine torque, generator torque, and discrete variable like transmission gear should be determined properly to achieve optimum control of the vehicle. A hierarchical control strategy constructed by tracking controller and allocation algorithm is proposed. Integral sliding mode control is adopted in the upper layer to track desired vehicle planar motion. The allocation problem is handled by a three-step control allocation algorithm based on quadratic programming, with carefully consideration of vehicle and powertrain features. Co-simulations with Matlab/Simulink® and TruckSim® show that the proposed coordinated control approach is capable of controlling vehicle planar motion and managing the complex series-parallel hybrid system simultaneously.

Brain-Computer Interface for wheelchair control operations: An approach based on Fast Fourier Transform and On-Line Sequential Extreme Learning Machine

ObjectiveThe paper aims to control an electric wheel chair with a Brain-Computer Interface (BCI) headset. This wheel chair would be helpful for disabled people who cannot move their hands and legs or basically suffering from cerebromedullospinal disconnection. The main objective is to map different facial expression to the movement of the wheelchair. MethodsThe headset used for this purpose comprises of an EEG cap which has a total of 16 electrodes connected out of which 14 electrodes are used for acquiring data and the rest 2 are used as ground and reference. To operate the wheelchair the subject has to place the cap on his/her head and different facial expressions (clench, smile, blink, etc.) are performed. The movement of muscles around the face due to facial expressions can be observed from the EEG signals being recorded. Each expression is linked to movement of the wheelchair. Signal is preprocessed to remove the artifacts and then features are extracted using Fast Fourier Transform. In this paper, for classification we have used state-of-the-art machine learning technique which is a slight variation of Extreme Learning Machine called as Online Sequential Extreme Learning Machine abbreviated as OS-ELM. ResultsAn overall accuracy of 97.62% was obtained using 10-fold cross validation. ConclusionThe proposed framework attains better classification accuracy compared to various other classifiers.

Vertical vibration control of an in‐wheel motor‐driven electric vehicle using an in‐wheel active vibration system

AbstractThe objective of this study is to present a novel in‐wheel (IW) active vibration system for an IW motor (IWM)‐driven electric vehicle to overcome the negative effects of vertical vibration due to road roughness and the impact of rotary inertial forces from the IWM. First, the reason for the poor ride comfort of the general electric wheel structure is examined by theoretical derivation. Second, a 6 degree‐of‐freedom (DOF) vehicle model is established and the corresponding cost function based on 10 ride comfort indexes is proposed. Third, a fuzzy optimal sliding mode (FOSM) control method is presented and the IW active vibration system is designed by applying this proposed control theory. Then, normalization and analytic hierarchy process (AHP) methodologies are adopted to select reasonable weighted coefficients of performance indexes. Finally, the advantages of the electric vehicle with the IW active vibration system are illustrated by MATLAB/Simulink. Analysis results demonstrate the feasibility and effectiveness of the proposed method.

Rolling centrifuge repulsion Force Spacecraft

A Rolling Centrifugal Repulsion force UFO Introduction: Any object that rolls along a straight line will generate a centrifugal repulsive force that is away from the body being rolled, it is rolling centrifugal repulsive force. Utilizing this phenomenon, rolling the round ring along the edge of the UFO's disk will produce a constant lift, and then use the electric wheel technology to set the ballast rock at the bottom of the UFO to change the position of the ballast stone at the bottom of the chamber. In order to change the position of the center of gravity of the UFO, the purpose of driving the UFO can be achieved.

Longitudinal vibration analysis and suppression of electric wheel system driven by in-wheel motor considering unbalanced magnetic pull

With the blowout of electric vehicles recently, the key parts of the electric vehicles driven by in-wheel motors named the electric wheel system become the core of development research. The torque ripple of the in-wheel motor mainly results in the longitudinal dynamics of the electric wheel system. The excitation sources are first analyzed through the finite element method, including the torque ripple induced by the in-wheel motor and the unbalanced magnetic pull produced by the relative motion between the stator and rotor. The accuracy of the finite element model is verified by the back electromotive force test of the in-wheel motor. Second, the longitudinal-torsional coupled dynamic model is established. The proposed model can take into account the unbalanced magnetic pull. Based on the model, the modal characteristics and the longitudinal dynamics of the electric wheel system are analyzed. The coupled dynamic model is verified by the vibration test of the electric wheel system. Two indexes, namely, the root mean square of longitudinal vibration of the stator and the signal-to-noise ratio of the tire slip rate, are proposed to evaluate the electric wheel longitudinal performance. The influence of unbalanced magnetic pull on the evaluation indexes of the longitudinal dynamics is analyzed. Finally, the influence of motor’s structural parameters on the average torque, torque ripple, and equivalent electromagnetic stiffness are analyzed through the orthogonal test. A surrogate model between the structural parameters of the in-wheel motor and the average torque, torque ripple, and equivalent electromagnetic stiffness is established based on the Bp neural network. The torque ripple and the equivalent electromagnetic stiffness are then reduced through optimizing the structural parameters of the in-wheel motor. It turns out that the proposed Bp neural network–based method is effective to suppress the longitudinal vibration of the electric wheel system.

Comparison of Thermographic Imaging and Other Diagnostic Techniques in Diagnosis of Cattle with Laminitis

Background: Lameness results in major economic losses on dairy farms. The proportion of lameness in cows are between 4-55%, the origin of 90% lameness are caused by foot diseases. Hoof abnormalities such as laminitis are major contributors to lameness. Aim of the study, compared with thermographic imaging (IRT) and radiographic, magnetic resonans (MR), computer tomography (CT), histopathological analysis on the diagnosis of laminitis.Materials, Methods & Results: Preliminary, the animals (20 Holstein-Fresian) were selected by lameness examination for evaluation of the for any obvious signs of disease. The animals were examined when rising and walking of the free stalls. Walking was very painful and clinical symptoms of general distress become present for laminitic group. The cows were scored on a 1 to 5 scale for their locomotion (1 = normal locomotion; 5 = severely lame). Thermographic examinations were performed the all animals after the routine clinical examination methods. The infrared images were taken from the dorsal view of all hoovesto monitor the temperature of coronary band. All images were scanned using a hand-held portable infrared camera (Wahl, Thermal Imager HSI3000 Series), which was calibrated to ambient temperature and absorptive conditions. Incentives radiological examinations, dorso-palmar and latero-medial shooting was done for using of (Regius Model 110 Konica, Minolta) 70 kV and 30 mAs for each claws. MRI images of all isolated digits were performed at the Department of Radiology, by using Siemens Symphony Erlangen, Germany. Continuous series of transversal, sagital and dorsoplantar scan were obtained from all digit. Computer tomography (CT), isolated digits were performed at the Imaging Department of Radiology, by using Siemens Symphony Erlangen, Germany. CT scanner was used to obtain contiguous slices from the region of the proximal sesamoid bones to the toe. Anterior side (laminar and perilaminar tissues) of the claws was uncovered with electric wheel. Tissue samples were taken 10% buffered formaldehyde solution after establishing a routine laboratory procedure following the prepared paraffin blocks 5 micrometers thick sections with hematoxylineosin dye method according to the staining. It was finally examined by light microscopy. The computer soft ware of the infrared thermal camera showed increased local temperature, by 0.5-1.5°C, between the normal and suspected regions for laminitic cases. Clinically, animals suspected of laminitis were showed general stiffness, lameness during walking difficulty. Examination of the claws was demonstrated of rings and plump appearance was evident in paries ungulae. The main damage was seen during trimming of the sole from no hemorrhages or discoloration of control group. The transversal MRI images provided excellent depictions of anatomical structures when compared to their corresponding pictures. Identifiable anatomic structure was labeled on the line drawings of the limb sections and on the corresponding CT images. Twenty out of 30 claws (65%) were shown laminitis statistical with histopathological examination. In histopathological examination; mononuclear cells and neutrophil granulocytes infilrations and edema, haemorrhagia, mild hyperemia in the lamellar region was remarkable in laminitic cases.Discussion: As a results, thermographic examination may have potential as a detection tool for laminitis. MR transversal images provided excellent depiction of anatomical structures and many biometric research in the bovine hoof can be easily investigated. The usefulness of IRT, MRI, CT in evaluating laminitis in the acute patient remains stil open. The use of diagnostic techniques during the initial active phase of laminitis as a means to increase the understanding of the disease and also serves as a justification for the development of an experiment involving live cows induces laminitis.

The assumptions of the engine design for mounting in the hub of the vehicle

The article presents the concept of engine design for installation in the hub of an electric car wheel. The authors presented the advantages and disadvantages of direct drive and possible applications of this type. The publication presents the results of preliminary design calculations for the electromagnetic circuit, the stator thermal model and the mechanical design of the engine.

Warning System Using Multicast Transmission for Pedestrian and Pedal-Cyclist Safety Against the Electric-Powered Driving Means in CVCN Network

This paper deals with a warning system for the safety of pedestrians/pedal-cyclists against electric-powered driving means including hybrid/PHEV/EV/FCEV and electric wheel on minor roads. These roads are a subset of connected-vehicle communication network(CVCN). The fatalities of pedestrians/pedal-cyclists declined recently compared to the early 2000s, but fatality rate of vehicle accidents is increasing. Clearly, this phenomenon will continue because of the increasing number of virtually silent hybrid/PHEV/EV/FCEV and electric wheels on the road.The hybrid/PHEV/EV/FCEV such as green electric-powered ones that can reduce environmental pollution are much more dangerous than traditional vehicles to pedestrians/pedal-cyclists on minor roads. The main risk factor of the electric-powered vehicles is that they are very quiet on the road because of the use of electric motor instead of engine. Thus, the safety warning system that can notify pedestrians/pedal-cyclists the dangerous approaches of vehicles from their behind have to be provided on minor roads.The proposed framework for safety warning system using multicast informs pedestrians/pedal-cyclists through smartphone when electric powered driving means are closing from their behind on minor roads. This is a new technology that uses vibration or sound of smartphone instead of artificial noise generation which is equipped to the electric powered driving means recently.

Integrated design of active suspension parameters for solving negative vibration effects of switched reluctance-in-wheel motor electrical vehicles based on multi-objective particle swarm optimization

As for the elastic layout of the direct-driven electric wheel system, the electromechanical coupling between the electromagnetic excitation of in-wheel driving motor and the weak damping system gives rise to negative vibration issues, which further deteriorate the dynamic performance of the electric vehicle. This paper presents a multi-objective optimization method for active suspension system to solve these issues by developing an integrated in-wheel motor electrical vehicles model. The unbalanced electromagnetic excitation from in-wheel driving motor is investigated by means of analytical and finite element methods. The Pareto solution set of optimal parameters are generated by the multi-objective particle swarm optimization method, and a comparison in vehicle dynamic performances is made to verify the targeted optimization method. The simulation results indicate that the optimized active suspension system attenuates the sensitivity of the vehicle system to electromagnetic excitation with a satisfactory balancing between vehicle ride comfort and stability as well as active suspension utilization.

Modular design and analysis of the x-by-wire center point steering independent suspension for in-wheel electric vehicle

In this article, a new design scheme of x-by-wire steering suspension system is proposed, which aims to solve the adaptation problem of the traditional steering system, suspension system, and the electric wheel. It meets the requirement of four-wheel independent steering function with large scale. The design keeps wheel steering center axis to coincide with the virtual wheel kingpin, thereby realizing the application of the center point steering independent suspension system in electric wheels. In addition, modular design is adopted to reduce the coupling between the system and the car body, thereby realizing the generalization of the front and rear steering suspension system, and it also decreases the number of components. Furthermore, the theoretical analysis and parameter design of the self-aligning torque of the suspension are carried out. The multi-body dynamics model of system is established, and the performance is simulated in both time domain and frequency domain. The comparison test shows that the center point steering independent suspension has higher feasibility. Finally, a prototype of the system is developed, which provides a new idea for the designing of chassis for electric vehicles.

Effects of Rotor Position Error on Longitudinal Vibration of Electric Wheel System in In-Wheel PMSM Driven Vehicle

The influence of a rotor position error on the longitudinal vibration of an electric wheel system is analyzed. To begin with, the influence of the rotor position error on the motor current and torque is deduced using coordinate transformation. The results show that the rotor position error will induce current harmonics, which cause further torque ripples with frequencies of kp res/ pfe and (6 ± kp res/ p ) fe ( k = 1, 2, 3, p is the number of motor pole pairs, p res denotes the number of resolver poles, and fe indicates the current fundamental frequency). Then, the dynamic model of the electric wheel is established, and the main vibration modes are determined. A comparative analysis of the motor's longitudinal vibration response with and without the rotor position error shows that the torque ripples with frequencies of kp res/ pfe deteriorate the vibrational characteristics of the electric wheel system over the entire working range. The torque ripples with frequencies of (6 ± kp res/ p ) fe increase the motor's vibration at low rotation speeds. Next, the influence rules of rotor position error on the current harmonics and longitudinal vibration are verified by electric wheel bench test. At last, a control method based on adaptive Kalman filter is proposed. This method can mitigate the adverse effects of the rotor position error according to the experimental results. This study provides a reference for the diagnosis of the motor rotor position error and the attenuation of electric wheel vibration.