Hub Motor Research Articles

Engine power distribution system for four-wheel drive autonomous electric vehicle

Nowadays, there is an active stage of development of advanced energy-saving technologies in the field of automotive industry, and therefore, electric vehicles are becoming increasingly popular. One of the main indicators of the efficiency of autonomous electric transport is the power reserve, the increase of which can be achieved by reducing the weight of the vehicle. In classic cars, the torque from the internal combustion engine is passed to the wheels by means of a transmission. In electric vehicles, due to the use of motor wheels, there is no need for a transmission, which significantly reduces the weight of the construction, as well as reduces maintenance and repair costs. The article considers the issue of power distribution of engines of an autonomous electric vehicle based on four-wheel hub motor. A mathematical description of an electronic differential for an electric car based on two and four motor wheels based on the Ackerman control principle is also obtained. A digital simulation of the four-wheel drive electric vehicle system was carried out in the MATLAB/Simulink software. Transients are obtained in terms of the speed of rotation of the engine shaft and the torque on the engine shaft, which satisfy the requirements for overregulation and quickness of the system.

Implementation and Experimental Validation of Efficiency Improvement in PM Synchronous Hub Motors for Light Electric Vehicles

The efficiency of permanent magnet synchronous hub motors (PMSHM) used in light electric vehicles (EVs) is lower than that used in commercial EVs. Therefore, in this study a high-efficiency radial-flux outer-rotor PMSHM was designed for light EVs. The high-efficiency motor will contribute to the reduction of the power consumption demand from the batteries of EVs, the longer life of the batteries and the longer uninterrupted operation of the system. The optimization objectives, such as motor sizing, number of slots and poles, air gap length, material selection, stator winding structure, stator slot shape, magnet thickness, and cutting method for stator sheets were considered to ensure high efficiency and low cogging torque. In this study, three validation stages were followed; electromagnetic analyzes with FEM, analytical calculations, and finally experimental validation. First, the design parameters of the motor were determined based on the analyses results obtained using ANSYS Maxwell software, and then validated both with the analytical calculations and experimental results. The comparison results show that the design data of the motor at the rated speed agree well with the analytical calculations and test results. After obtaining the optimized motor design, the motor was installed on a prototype electric car for the road test. During the test drive, the motor performed successfully and operated compatibly with the rest of the electric vehicle systems such as the motor driver and the battery.

Modeling, Simulation and Implementation of All Terrain Adaptive Five DOF Robot.

The ability of an off-road robot to traverse obstacles determines whether the robot can complete complex environmental tasks. In order to improve the off-road ability of off-road robots, this paper proposes a new design idea, in which four hub motors are the power system of the robot, the steering system of the robot is composed of a steering machine and a stepping motor, and a five degree of freedom robot model is established. The body structure is designed according to the characteristics of arthropods. The body structure is divided into three modules, and the connecting rod is used as the joint system of the robot to connect the three parts. The body can deform when facing complex obstacles, so as to adapt to different terrains. Then the body structure is simplified, and a mathematical model is established to describe the mathematical relationship between body joint changes. In order to verify the ability of the adaptive all-terrain cross-country robot to traverse obstacles, the load-bearing experiment and obstacle-crossing simulation experiment were carried out through Adams software, and the continuous traversing performance at low obstacles and the ability to break through high obstacles were tested, respectively. The experimental results prove that the designed adaptive all-terrain off-road robot is feasible, has good carrying capacity, and has good passability in the face of low obstacles and high obstacles. Using Ansys software to perform finite element analysis on the wheel connection, the experimental results show that the strength meets the material strength requirements. Finally, a real vehicle test is carried out to verify the correctness of the simulation results.

Research on Direct Yaw Moment Control of Electric Vehicles Based on Electrohydraulic Joint Action

To solve the problem of lateral instability of the vehicle caused by insufficient lateral force of the tires due to the insufficient torque provided by the motor to the tire when the vehicle turns sharply or avoids obstacles in an emergency, a layered control method is used to design a lateral stability control system. The upper decision layer selects the yaw rate and the sideslip angle of the center of mass as the control variables and uses the joint state deviation of the yaw rate and the sideslip angle of the center of mass and the rate of change of the deviation as the input of the sliding mode variable structure controller to calculate the additional yaw moment required to maintain vehicle stability. The lower torque distribution layer realizes the distribution of torque through the electro-hydraulic coordinated control method: the torque distribution rule based on real-time load transfer calculates the torque corresponding to the control wheel and generates the torque through the hub motor and transmits it to the wheel. When the torque output from the motor cannot provide sufficient torque for the vehicle, hydraulic braking is used as a compensating control, and the difference between the required yaw torque and the motor-generated yaw torque is used as the required torque for hydraulic control to calculate the wheel cylinder pressure required to brake the wheels. Based on the joint simulation model of MATLAB/Simulink and Carsim, the sine and double shift line working condition are selected for stability simulation experiments. From the simulation results, it can be seen that the yaw rate and sideslip angle of the center of mass of the vehicle with sliding mode control and electro-hydraulic coordinated control almost coincide with the ideal value curve, which are both smaller than the output parameters of the uncontrolled vehicle. From the perspective of the motor output torque, compared with pure motor control, the effect of electro-hydraulic coordinated control is better, and the hydraulic system can compensate for the braking torque in time and enhance the lateral stability of the vehicle. The designed control strategy can make the yaw rate and the sideslip angle of the center of mass of the vehicle follow the reference value better, which can effectively avoid the vehicle sideslip and instability and improve the vehicle yaw stability and driving safety. However, due to the limitations of experimental equipment, the proposed method could not be applied to the real vehicle test. The real vehicle test can better test the control effect of the proposed method.

Lightweight design of the planetary gear reducer of reduction drive hub motors

Hub motor is the development direction of new energy vehicles in the future. Usually, the reduction drive hub motor is directly arranged in the narrow rim space, so there are strict restrictions on the volume and weight of its reducer. This paper presents a highly integrated transmission scheme which can improve the working life of the reducer. For the planetary gear reducer integrated by the reduction drive hub motor, a multi-objective optimization function with minimum volume and large coincidence degree is constructed. In terms of constraints, the necessary conditions of planetary gear transmission are fully considered, the gear module meets the requirements of national standards, and the strength conditions of gear transmission. Using genetic optimization algorithm, the optimal solution satisfying the constraints is obtained. The optimization results show that the coincidence degree of the engagement between the sun gear and the planetary gear increases by 67% and the equivalent volume decreases by 31%, which can reduce the volume and reduce the transmission noise at the same time.

Research on Simulation Method for Wear for Dynamic Seal in Axial Flux Hub Motor

A simulation method for the wear of a dynamic seal in an axial flux hub motor is proposed in this work. A quasi-3D magnetic model without deflection between the axes of a stator and a rotor is built. An analytical model for unbalanced magnetic force considering the cogging effect and axial deflection is presented based on the quasi-3D magnetic model. Boundary conditions of the dynamic seal are obtained through solving the FE model of a hub motor. Both the structural and thermal FE model of a dynamic seal are built and the thermal–structural coupling method is given. A dynamic wear simulation method is displayed based on the mesh reconstruction method proposed previously. It is proved through the contrast with the experimental results that the presented method is feasible.

Design and locomotion analysis of a close-chain leg-wheel mobile platform

PurposeTo take the advantages of terrain-adaptive capability of legged platform and fast-moving ability of wheeled platform, this paper aims to design a leg-wheel mobile platform for obstacle surmounting and analyze the feasibility and locomotivity of different moving modes.Design/methodology/approachThe platform consists of six leg-wheel units. Each of the units has a close-chain mechanical leg and an actuated wheel at the end of the leg. The platform moves with two modes: legged mode and leg-wheel composite mode. The legged mode achieves high mobility driven by crank motors, while the leg-wheel composite mode achieves obstacle-surmounting ability actuated by crank motors and pitch link motors and obtains high efficiency with the hub motors. The gait planning in different modes has been carried out and the obstacle-surmounting capacity has been analyzed.FindingsBased on the results of kinematic analysis and gait planning of the close-chain leg-wheel platform, the high mobility and efficiency obstacle-surmounting ability are demonstrated with the two movement modes. The feasibility of the design and the performance of the mobile platform is verified with the prototype experiment. The results of this paper show that the platform possesses good obstacle-surmounting capability.Originality/valueThe work presented in this paper is a novel exploration to design a close-chain leg mechanism and with an actuated wheel in series. The close-chain leg mechanism has the advantages of high leg lift and single degree of freedom characteristics, which makes the platform obtain the ability of obstacle-surmounting.

Pedalling Comfort of a Custom Pedal Series Hybrid Drivetrain in a Cargo E-Tricycle

A Pedal Series Hybrid Drivetrain (PSHD) uses an electrical power transmission rather than a chain, belt, or shaft. It creates exciting opportunities for the vehicle's design, but pedalling does not always feel comfortable. This study evaluates the pedalling comfort of a custom PSHD in an electric cargo tricycle. In this PSHD, pedal-drive generator converts human mechanical power to electrical power that is used by two hub motors to propel the vehicle. The pedal-driven generator is mechanically decoupled from the propulsion of the vehicle. Therefore, natural pedalling is replicated using a custom programmable controller for the mechanical resistance of the generator. Test subjects reported a very comfortable pedalling feeling, however slightly different from the feeling of a traditional e-bike. They failed to explain the differences in more detail. Further measurements show that the pedal generator of the PSHD has the same power cycle as the pedals in a traditional e-bike, but the pedal generator has a greater variation in the instantaneous angular velocity.

Detachable stepper design

In view of the shortcomings of the existing stepper in the market, this paper makes some improvement designs to improve the performance of all aspects as much as possible. In this paper, the overall structure scheme of the dismountable walking machine is determined firstly. Secondly, the size design of the key parts of the walking machine (base plate, connecting table, drive shaft and driven shaft) and the strength check of the key parts (shaft and key connection) are carried out. Finally, the description and application of the control are given. The small part design, the use of hub motor and its better control and detachable features make the walking machine more flexible and convenient. The detachable walking machine is flexible, convenient, easy to operate and simple in structure, which has certain practical value and research significance.

Optimal design and dynamic control of the HMDV inertial suspension based on the ground-hook positive real network

The positive real network of the inertial suspension system can effectively suppress the low frequency vibration of vehicle, but the improvement effect of it at medium and high frequency band is not significant. The ground-hook control can obviously reduce the vibration of the dynamic tire load at high frequency band. The motors of Hub Motor Drive Vehicle (HMDV) can increase the dynamic tire load, so the paper combines the inertial suspension and the ground-hook control to achieve the reduction of the dynamic tire load at the wider frequency domain. Firstly, the quarter-vehicle kinetic model with the Switched Reluctance Motor (SRM) is established. Then the constraints of the first order and the second order ground-hook positive real networks are identified, and the structural parameters are optimized respectively. In addition, the influences of the first order and the second order ground-hook positive real networks on the dynamic tire load are analyzed. Lastly, the controller based on the Model Reference Adaptive Control (MRAC) is designed to control the mechatronic inerter to achieve the ideal performance output. Simulation results show that, the Root Mean Square (RMS) values of dynamic tire load and suspension working space of the controllable inertial suspension is reduced by 18.21%, 28.26% respectively by comparing to the conventional suspension. And the dynamic tire load is suppressed at the wider frequency domain, which verify that the advantages of the inertial suspension and the ground-hook control are utilized effectively.

Vertical Negative Effect Suppression of In-Wheel Electric Vehicle Based on Hybrid Variable-Universe Fuzzy Control

To suppress a negative effect brought by introducing hub motor in vertical vibration of the body and that of a hub motor, a suppressing vertical negative effect algorithm of in-wheel electric vehicle is proposed based on hybrid variable universe fuzzy control (VUFC). Vertical accelerations of the body and that of the hub motor are taken as optimization objects, and to control the main suspension damper and in-wheel damper simultaneously, the semi-actively VUFC algorithm is adopted to improve vertical vibration characteristics effectively. The simulated results show that the peak and root mean square (RMS) of body vertical acceleration (VA) are optimized by 21.0% and 19.6%, respectively, after optimization compared to the original in-wheel electric model, the peak and RMS of hub motor VA are optimized by 30.1% and 32.5%, respectively, and the vertical negative effect is suppressed significantly.

Vibration Suppression of Hub Motor-Air Suspension Vehicle

Aiming at the negative vibration effect caused by the increased unsprung mass of the hub motor-air suspension (HM-AS) vehicle and the unbalanced magnetic force (UMF) of the hub motor, a linear quadratic regulator (LQR) air suspension control strategy based on a genetic algorithm is proposed. Considering the coupling effect of road surface excitation and UMF, the model of the HM-AS vehicle is established. Then, according to optimal control theory and the genetic algorithm, the LQR controller is designed to suppress the vibration of the HM-AS vehicle, and the weight matrix of the LQR controller is optimized through the genetic algorithm. The simulation results show that the proposed LQR control strategy effectively improves the ride comfort and motor safety of the HM-AS vehicle.

DESIGN AND DEVELOPMENT OF ANTI-LOCK BRAKING SYSTEM FOR ELECTRIC VEHICLE

Modern automobiles are more than just mechanical gadgets. Because of the connectivity which is increased between the vehicular networks and the present outside world, hackers now have more security flaws via which they can cause exploitations of a vehicular network. The CAN network that is controlled area network is a common communication bus protocol that helps ECU that is electronic control units in a vehicular network to communicate with one another. The safety systems which connect to network, on the other hand, are particularly vulnerable to malicious internal or external assaults due to their varied security flaws. This study presents a new way for introducing a Message Authentication System to enhance CAN security. The electric vehicle is basically driven by the lithium-ion battery coupled to hub motor. The motor needs a power supply to run which can be from an array of source. Electric vehicles do not emit any carbon dioxide because they are fuelled by electricity rather than any other fuel. Carbon dioxide contributes to the greenhouse effect. The design of the electric vehicle includes Hub motor which is brushless dc motor the outer part which rotates is called rotor and permanent magnets is used above the rotor inner part is called as stator and windings are used above it. Hence hub motors are dc motors as they work on dc voltage. Lithium-ion battery is made up of anode, cathode, electrolyte and two current collectors (positive and negative). Li-ion batteries can be recharged 100 times and are more stable. Henceforth, high efficiency with less noise and environment friendly electric vehicle is designed. The method that is proposed and implemented in a MATLAB and Simulink of CAN-based in the networks of the vehicle design along with ABS. By introducing additional security characteristic information unique to each transmitted CAN packets, model that applies Authentication of messages with a safety mechanism for any unknown detection that is intruded. The suggested method's result analysis revealed the fact that the feature which is security

DESIGN AND DEVELOPMENT OF ANTI-LOCK BRAKING SYSTEM FOR ELECTRIC VEHICLE

Modern automobiles are more than just mechanical gadgets. Because of the connectivity which is increased between the vehicular networks and the present outside world, hackers now have more security flaws via which they can cause exploitations of a vehicular network. The CAN network that is controlled area network is a common communication bus protocol that helps ECU that is electronic control units in a vehicular network to communicate with one another. The safety systems which connect to network, on the other hand, are particularly vulnerable to malicious internal or external assaults due to their varied security flaws. This study presents a new way for introducing a Message Authentication System to enhance CAN security. The electric vehicle is basically driven by the lithium-ion battery coupled to hub motor. The motor needs a power supply to run which can be from an array of source. Electric vehicles do not emit any carbon dioxide because they are fuelled by electricity rather than any other fuel. Carbon dioxide contributes to the greenhouse effect. The design of the electric vehicle includes Hub motor which is brushless dc motor the outer part which rotates is called rotor and permanent magnets is used above the rotor inner part is called as stator and windings are used above it. Hence hub motors are dc motors as they work on dc voltage. Lithium-ion battery is made up of anode, cathode, electrolyte and two current collectors (positive and negative). Li-ion batteries can be recharged 100 times and are more stable. Henceforth, high efficiency with less noise and environment friendly electric vehicle is designed. The method that is proposed and implemented in a MATLAB and Simulink of CAN-based in the networks of the vehicle design along with ABS. By introducing additional security characteristic information unique to each transmitted CAN packets, model that applies Authentication of messages with a safety mechanism for any unknown detection that is intruded. The suggested method's result analysis revealed the fact that the feature which is security that has been proven to be very effective method that detects and blocks any third-party that has been intruded into the anti-lock braking system through the controlled area network bus protocol, The stability is maintained between all coupled Electronic control units. Hence method that is implemented with the design of electric vehicle gives the best results of the output.

Design and Development of Economical E-Bicycle

People around the globe using fuel powered bikes for city riding and short distance mobility. Which is one of the reason for increasing CO2 emission parallelly counts for increasing global warming. Because of this, electric bicycle come into the picture as an alternative. The need for an affordable and efficient transportation system has created a growing demand for Electric Bicycles in India and this project is seen as an opportunity, rather a challenge to design and develop a leading electric bicycle class for commute to quotidian. The electric bicycle has wheels that are specially powered by an electric hub motor, powered by a battery pack,that provides the required power. The electric bicycle has an electric motor with an intelligent controller and a battery pack connected to efficient cable systems and monitoring tools. Also, the use of electric bicycles will create less pollution and keep the environment alive. These project research mainly highlights into the design and development of a smart, Economical, and secure electric bicycle achieved through market research, studying the available options to determine the customers need and there requirement.

A Novel Step Current Excitation Control Method to Reduce the Torque Ripple of Outer-Rotor Switched Reluctance Motors

Featured in low-speed and high-torque operation, outer-rotor switched reluctance motors (OSRMs) have the potential to be widely deployed in low-speed commuter and logistics vehicle applications. In this paper, a five-phase OSRM and the control method featuring torque ripple reduction has been proposed, which can be applied as the wheel hub motor in the electric vehicles. The simulation was carried out to analyze the OSRM operation. The electromagnetic characteristics of single-phase and two-phase hybrid excitation mode, as well as step current excitation mode, were compared and analyzed. To solve the problem of the large torque ripple of OSRMs under traditional excitation modes, the torque ripple suppression method based on step current excitation was also studied. The experiment design, including motor start-up control, speed control, and torque ripple reduction, are presented to verify the system torque ripple mitigation method.

Design of an Anti-Windup PID Algorithm for Differential Torque Steering Systems

The EV (electric vehicle) with a wheel hub motor has the advantage of independent driving torque distribution for each wheel, which allows the vehicle performance to be improved. Therefore, a lot of work has been done to investigate the torque allocation algorithm for the mechanical and differential torque integration steering system. To investigate the differential steering process, the 2 DOF (degree of freedom) dual-track reference models with linear and nonlinear tire models are established, and based on the steering process analysis and yaw rate gain calculation, a BP-NN (backpropagation neural network) model is initiated to maintain the accuracy of the calculated yaw rate gain. The limitation of DTSS (differential torque steering system) and the difference of reference models with linear and nonlinear tires are drawn. In addition, an anti-windup variable PID (proportion integration differentiation) controller is designed for the torque distribution. Based on the built 8 DOF model, the vehicle performance indicators are calculated and compared, the gap between the models with linear and nonlinear tires is non-negligible, and a reference model with a nonlinear tire model is recommended for the relevant research. The anti-windup variable PID controller has a better performance than the normal PID controller except for the stability phase plane indicator.

Ride comfort analysis of electric vehicle using hub motor as dynamic absorber

Abstract To resolve the problems of adding unsprung mass and worsening ride comfort of hub motor drive electric vehicles, a new drive system with hub motor as dynamic absorber is studied and proposed. The mathematical models of the new hub motor drive system and the centralized motor drive system are established, and their ride comfort is compared and analyzed. The impact of dynamic absorber parameters on ride comfort of the new hub motor drive system is analyzed, and the parameter sensitivity is calculated. The results show that the body acceleration, suspension dynamic deflection, wheel dynamic load of the new hub motor drive system are better than those of the centralized motor drive system, and the dynamic absorber parameters have a great effect on the electric vehicle performance.

MPC-Based Integrated Control of Trajectory Tracking and Handling Stability for Intelligent Driving Vehicle Driven by Four Hub Motor

Aiming at the problem of trajectory tracking and handling stability of intelligent four hub-motor independent-drive electric vehicle at high speed, an integrated control strategy based on model predictive control (MPC) is proposed. Firstly, a kinematics preview model is established considering the adaptive change of preview distance with longitudinal vehicle speed. Secondly, combined with the proposed preview model and considering the vehicle dynamic characteristics, an upper level controller of MPC is created to track the lateral deviation, heading angle deviation, sideslip angle and yaw rate to obtain the optimal solution of front wheel angle and additional yaw moment, which realize the control of handling stability while ensuring the trajectory tracking accuracy at same time. Then considering the varying road adhesion and the influence of longitudinal slip at the four tires, a lower level controller composed of torque optimal control and sliding mode controller is designed to realize the optimal torque distribution of four hub motors. Finally, through the co-simulation of MATLAB / Simulink and CarSim and the hardware-in-the-loop experiment, it is verified that the proposed integrated control strategy can effectively improve the path tracking accuracy and ensure the vehicle handling stability at high speed. Compared with the general MPC strategy, who does not control the sideslip angle and yaw rate with no preview model, the cumulative lateral tracking error of the integrated control is reduced by 51.9% and 87.7% respectively.

Fault-Tolerant Operation of a Six-Phase Permanent Magnet Synchronous Hub Motor Based on Model Predictive Current Control With Virtual Voltage Vectors

This paper proposes a model predictive current control (MPCC) compensation method based on virtual voltage vectors for single-phase open-circuit faults of an asymmetric six-phase permanent magnet synchronous hub motor (PMHSM). The proposed strategy adopts the normal vector space to decompose the transformation matrix without reconfiguring the controller topology. By analyzing the difference between the open-circuit phase voltage and the state of health, the disturbance term of the prediction vector in the α-β and x-y subspaces is obtained. 64 voltage vectors are obtained from the switching states of the 6-phase two-level inverter, and then these 64 voltage vectors are appropriately compensated and synthesized into 24 new virtual voltage vectors. The new virtual vectors avoid the adjustment of the MPCC weighting factors and the synthesized virtual vectors can suppress current harmonics. Finally, the experimental results show the effective performance of the method before and after the fault-tolerant operation.