In-wheel Motor Research Articles

Negative effect and optimal control of in-wheel motor with inclined eccentricity on driving safety for electric vehicle

During the driving process of the in-wheel drive electric vehicle, the air gap eccentricity of the motor caused by external disturbance cannot be avoided, resulting in a negative effect on vehicle dynamics. In this paper, the negative effect of vehicle lateral dynamics caused by motor-inclined eccentricity and the corresponding control method are studied. According to the Maxwell stress tensor and the air gap permeance correction coefficient, the unbalanced radial force under the inclined eccentricity of the in-wheel motor is characterized, and the corresponding vehicle dynamics model is established. Based on the vehicle dynamics model, different steering conditions are set to explore the influence of inclined eccentricity on the negative effect of vehicle lateral dynamics. It is found that the inclined eccentricity affects the handling stability of the vehicle under normal conditions and affects the rollover stability under extreme conditions. In order to solve these problems, the integrated control strategy is formulated by using the steering and driving system of an electric vehicle, and the particle swarm optimization algorithm is introduced to optimize it. The simulation results show that the proposed integrated optimal control of active rear-wheel steering and direct yaw control can effectively alleviate the negative effect of vehicle lateral dynamics caused by the inclined eccentricity of the in-wheel motor under different working conditions.

Analysing the possibility of using a hydraulic transmission with motor wheels for the nomad at off-roader

Problem. The creation of transport vehicles for operation in difficult road conditions requires solving a complex of problems related to the fulfilment of the necessary requirements for speed and traction characteristics, in particular, shifting modes, overcoming climbs, manoeuvrability and increased speed with its stepless change, anti-skid properties. Such requirements are achieved thanks to constructive solutions in transmissions of various types. Goal. The aim is an attempt to create a full-flow continuously variable transmission with hydrostatic transmission and motor-wheels instead of a step-mechanical one to improve the technical characteristics of the all-terrain vehicle and the technological possibilities of manufacturing the transmission by the block method when using standard components. Methodology. Based on the analysis of the technical characteristics of the analogue all-terrain vehicle with a mechanical multi-gear transmission and a review of achievements in modern hydrostatic transmission with hydraulic motor-wheels, static calculations were carried out to assess the possibility of creating a stepless full-flow hydro volume transmission and building its hydraulic schematic diagram. Calculations are based on mathematical models created on the basis of the laws of mechanics and hydraulics. The results. According to the results of the calculations, it has been shown that it is fundamentally possible to create a stepless hydrostatic transmission for an all-terrain vehicle with the specified traction and speed characteristics. Further research is proposed on the analysis of the dynamics of the hydrostatic transmission of the all-terrain vehicle and the creation of a corresponding experimental model of the vehicle. Originality. For the analogue all-terrain vehicle, the hydraulic motor-wheels required for the working volume were selected, which provide the parameters of traction and speed characteristics and allow creating an original transmission without the use of reducers and gearboxes. Practical meaning. The obtained results are planned to be considered as recommended for carrying out a functional and cost analysis in the design and determination of technological possibilities in the manufacture of a hydrostatic transmission of an all-terrain vehicle. It is also proposed to consider the method of calculating the hydrostatic transmission of an all-terrain vehicle in the educational process for master's students of industrial mechanical engineering when studying the disciplines related to the design of hydraulic drives and their tests.

An Asymmetric Independently Steerable Wheel for Climbing Robots and Its Motion Control Method

Climbing robots, with their expansive workspace and flexible deployment modes, have the potential to revolutionize the manufacturing processes of large and complex components. Given that the surfaces to be machined typically exhibit variable curvature, good surface adaptability, load capacity, and motion accuracy are essential prerequisites for climbing robots in manufacturing tasks. This paper addresses the manufacturing requirements of climbing robots by proposing an asymmetric independently steerable wheel (AISW) for climbing robots, along with the motion control method. Firstly, for the adaptability issue of the locomotion mechanism on curved surfaces under heavy load, an asymmetric independently steerable wheel motion module is proposed, which improves the steering difficulty of the traditional independently steerable wheel (ISW) based on the principle of steering assisted by wheels. Secondly, a kinematic model of the AISW chassis is established and, on this basis, a trajectory tracking method based on feedforward and proportional–integral feedback is proposed. Comparative experimental results on large, curved surface components show that the asymmetric independently steerable wheel has lower steering resistance and higher motion accuracy, significantly enhancing the reachability of climbing robots and facilitating their application in the manufacturing of large and complex components.

Coordination control strategy of motion stability and tire slip for electric vehicle driven by in-wheel-motors

The Direct Yaw Moment Control (DYC) is a widely utilized technique for electric vehicles equipped with In-Wheel Motors (IWMs) to ensure yaw stability. However, most existing DYC studies calculate the additional control yaw moment solely based on the torque differences among the four IWMs, disregarding the nonlinear tire characteristics and wheel rotational movements. When road conditions are poor or torque changes are intense, the tire may slip, preventing it from generating the required longitudinal tire force for the desired direct yaw moment. To address this challenge, this study introduces a coordination control strategy for motion stability and tire slip in electric vehicles (EV) driven by IWMs. To enhance control performance, the nonlinear tire characteristics and wheel rotational movements are integrated into the modeling process when calculating tire forces. Additionally, a state and parameter coupling estimation algorithm is utilized to obtain feedback on tire parameters and vehicle motion states. Using these estimation results as a foundation, a coordination strategy is developed to achieve reference motion state tracking and tire slip ratio control. The Model Predictive Control (MPC) algorithm is employed to solve the control problem with constraints on both control inputs and outputs, and the estimation results are utilized to update the control model as well as provide states feedback. Simulations and experiments are conducted to validate the feasibility and effectiveness of the proposed control strategy. The results demonstrate that our proposed control strategy effectively improves vehicle stability by coordinating vehicle motion and tire slip control.

Research on torque ripple suppression of in-wheel fractional slot permanent magnet synchronous motors based on auxiliary slots

Research on torque ripple suppression of in-wheel fractional slot permanent magnet synchronous motors based on auxiliary slots

Comparison between an Adaptive Gain Scheduling Control Strategy and a Fuzzy Multimodel Intelligent Control Applied to the Speed Control of Non-Holonomic Robots

The main objective of this work is to address problems related to the speed control of mobile robots with non-holonomic constraints and differential traction—specifically, robots for football games in the VSS (Very Small Size) category. To achieve this objective, an implementation and comparison is carried out between two control strategies: an adaptive control strategy by gain scheduling and a fuzzy multimodel intelligent control strategy. The mathematical models of the wheel motors for each operating range are approximated by a first-order system since data acquisition is performed using the step response. Tuning of the proportional and integral gains of the local controllers is carried out using the root locus technique in discrete time. For each mathematical model obtained for an operating range, a local controller is tuned. Finally, with the local controllers in hand, the implementation of and comparison between the gain scheduling adaptive control strategy and the fuzzy multimodel intelligent control strategy are carried out, in which the control strategies are programmed into the low-level code of a non-holonomic robot with a differential drive to verify the performance of the speed tracking dynamics imposed on the wheel motors to improve robot navigation during a robot football match.

Analytical Investigation of Vertical Force Control in In-Wheel Motors for Enhanced Ride Comfort

This study explores the effectiveness of vertical force control in in-wheel motors (IWMs) to enhance ride comfort in electric vehicles (EVs). A dynamic vehicle model and a proportional ride-blending controller were used to reduce vertical vibrations of the sprung mass. By converting the state-space model into a transfer function, the system’s frequency response was evaluated using road profiles generated according to ISO 8608 standards and converted into Power Spectral Density (PSD) inputs. The frequency-weighted acceleration (aw) was calculated based on ISO 2631 standards to measure ride comfort improvements. The results showed that increasing the proportional gain (Kp) effectively reduced the frequency-weighted acceleration and the RMS of the vertical acceleration of the sprung mass. However, the proportional gain could not be increased indefinitely due to the torque limitations of the IWMs. Optimal proportional gains for various road profiles demonstrated significant improvements in ride comfort. This study concludes that advanced suspension technologies, including the proportional ride-blending controller, can effectively mitigate the challenges of increased unsprung mass in IWM vehicles, thereby enhancing ride quality and vehicle dynamics.

Probing rotaxane dynamics with 19F NMR/MRI: Unveiling the roles of mechanical bond and steric hindrance

BackgroundDeciphering the molecular dynamics (MD) of rotaxanes is crucial for designing and refining their applications in molecular devices. This study employed fluorine-19 nuclear magnetic resonance (19F NMR) and magnetic resonance imaging (MRI) to unveil the interplay between mechanical bonds and steric hindrance in a series of fluorinated rotaxanes. Results1H/19F NMR revealed stable “Z”-shaped wheel conformations minimizing steric clashes and favoring π-π interactions with the axle. Utilizing fluorines and axle protons as reporters, 1H/19F relaxation rates and solid-state 19F NMR studies demonstrated that mechanical bond primarily governs wheel motion, while steric hindrance dictates axle movement. Intriguingly, mechanical bond mainly affects local axle groups, leaving distant ones minimally impacted. MD simulations corroborated these findings. Temperature-dependent 19F NMR indicated that energy input enhances rotational motion and wheel conformational transitions. Furthermore, the drastic increase in 19F relaxation rates upon mechanical bond formation and steric hindrance enables sensitive and selective 19F MRI visualization of MD changes. SignificanceThis study, by elucidating the roles of internal and external factors on rotaxane molecular dynamics using 19F NMR/MRI, offers valuable insights that can advance the field of rotaxane-based molecular devices.

The Control of Handling Stability for Four-Wheel Steering Distributed Drive Electric Vehicles Based on a Phase Plane Analysis

For the sake of enhancing the handling and stability of distributed drive electric vehicles (DDEVs) under four-wheel steering (4WS) conditions, this study proposes a novel hierarchical control strategy based on a phase plane analysis. This approach involves a meticulous comparison of the stable region in the phase plane to thoroughly analyze the intricate influence of the front wheel angle, rear wheel angle, road adhesion coefficient, and longitudinal speed on the complex dynamic performances of DDEVs and to accurately determine the critical stable-state parameter. Subsequently, a hierarchical control strategy is presented as an integrated solution to achieve the coordinated control of maneuverability and stability. On the upper control level, a model predictive control (MPC) motion controller is developed, wherein the real-time adjustment of the control weight matrix is ingeniously achieved by incorporating the crucial vehicle stable-state parameter. The lower control level is responsible for the optimal torque allocation among the four wheel motors to minimize the tire load rate, thereby ensuring a sufficient tire grip margin. The optimal torque distribution for the four wheel motors is achieved using a sophisticated two-level allocation algorithm, wherein the friction ellipse is employed as a judgement condition. Finally, this developed control strategy is thoroughly validated through co-simulation utilizing the CarSim 2019 and Simulink 2020b commercial software, demonstrating the validity of the developed control strategy. The comparative results indicate that the presented controller ensures a better tracking capability to the desired vehicle state while exhibiting improved handling stability under both the double lane shifting condition and the serpentine working condition.

Enhancing brushless DC motor wheel design using single and multi-objective heat transfer search optimization approach

Enhancing brushless DC motor wheel design using single and multi-objective heat transfer search optimization approach

Sliding mode control strategy based on disturbance observer for permanent magnet in-wheel motor

A novel sliding mode control(NSMC) strategy combined with a fast terminal sliding mode observer(FTSMO) is suggested in this paper to solve the parameter variation issue of permanent magnet in-wheel motor(PMIWM) installed in the distributed drive electrical vehicle (DDEV). First, a novel sliding mode power converging law is employed to enhance the response speed of the PMIWM controller. Second, an FTSMO is suggested to compensate for the parameter variation of the PMIWM system to strengthen the robustness of the control object. Finally, a fuzzy controller is designed to adjust the control parameters of the NSMC to optimize the control performance. Several simulations and experiments demonstrate that the proposed FTSMO-NSMC scheme can precisely compensate for parameter variation of the control object and improve control accuracy effectively.

Vertical-Longitudinal Comprehensive Control for Vehicle With In-Wheel Motors Considering Energy Recovery and Vibration Mitigation

Vertical-Longitudinal Comprehensive Control for Vehicle With In-Wheel Motors Considering Energy Recovery and Vibration Mitigation

Performance materials with variations of tractor drive wheel fin angle and low-cost manufacturing analysis

Nowadays, the demand for workers in the agriculture industry has decreased and there is a need for rising mechanization in the agriculture process. The agriculture process that requires mechanization is cultivating. The rice cultivator has to be as light as possible, so requires a lighter material but is also strong enough. The correlation between the rice transplanter tool and the wheels is closely related to soil conditions. The selection of wheel materials is considered based on the characteristics of the planting area. In addition, another influence variable is the angle of the fin in the rice transplanter wheel. Material of rice transplanter wheel has been established, these are 1023 carbon steel sheet, AISI 1020 steel cold rolled, AISI 316 stainless steel. The angle of the fin was varied, these are 30, 35, and 40, this fin will give an effect on the traction result of rice transplanter wheel movement. The combination of lightweight material and the appropriate fin angle of the rice transplanter wheel has the best traction result. As a result of this research, the suitable material for the rice transplanter wheel was carbon steel and the fin’s angle was 30. This research involved a comparison and analysis of material strength under various fin angles. The evaluation of stress criteria was conducted using design values to determine the most reliable final product design. The paper contributes by illustrating how to represent the final decision on the combination of design and materials, incorporating a cost index assessment.

Adaptive Control for Suspension System of In-Wheel Motor Vehicle with Magnetorheological Damper

This study proposes two adaptive controllers and applies them to the vibration control of an in-wheel motor vehicle’s (electric vehicle) suspension system, in which a semi-active magnetorheological (MR) damper is installed as an actuator. As a suspension model, a nonlinear quarter car is used, providing greater practical feasibility than linear models. In the synthesis of the controller design, the values of the sprung mass, damping coefficient and suspension stiffness are treated as bounded uncertainties. To take into account the uncertainties, both direct and indirect adaptive sliding mode controllers are designed, in which the principal control parameters for the adaptation law are updated using the auto-tune method. To reflect the practical implementation of the proposed controller, only two accelerometers are used, and the rest of the state values are estimated using a Kalman observer. The designed controller is applied to a quarter car suspension model of an in-wheel motor vehicle featuring an MR damper, followed by a performance evaluation considering factors such as ride comfort and road holding. It is demonstrated in this comparative work that the proposed adaptive controllers show superior control performance to the conventional proportional–integral–derivative (PID) controller by reducing the vibration magnitude by 50% and 70% for the first and second modes, respectively. In addition, it is identified that the second mode (wheel mode) of the in-wheel motor vehicle is more sensitive than the first body mode depending on the mass ratio between the sprung and unsprung mass.

Design and analysis of a mobile robot with novel caster mechanism for high step-overcoming capability

The mobile robot market is experiencing rapid growth, playing a pivotal role in various human-centric environments like restaurants, offices, hotels, hospitals, apartments, and factories. However, current differential-driven mobile robots, employing conventional casters and wheel motors, encounter limitations in surmounting uneven surfaces and high steps due to constraints caused by wheel and caster dimensions. While some robots address these challenges by incorporating optimized wheel shapes and additional motors, this invariably leads to an increase in both size and cost. This research introduces an innovative solution; a novel caster-wheel mechanism designed to enhance the high-step overcoming capability of mobile robots without necessitating alterations to their overall size and structure. By incorporating a sub-wheel linked to a passive joint, the driving force is effeciently converted into a vertical force, thereby empowering the mobile robot to navigate obstacles 85% larger than its caster-wheel radius. Crucially, this innovative caster can be seamlessly manufactured and integrated, offering the potential for widespread adoption as a replacement for conventional casters. Validation through comprehensive simulations and experiments conducted on a prototype robot has been presented in this article, demonstrating its effectiveness even at a robot velocity of 0.1 m/s. This pioneering solution holds significant promise for diverse applications across various mobile robot configurations, presenting a compelling avenue for further exploration and implementation in the field.

An indoor delivery robot based on YOLOv8 and ROS

Abstract Aiming at the problems of inflexible movement, poor operation efficiency, low space utilization in the storage area and poor compatibility of placed items, intelligent route planning ability and weak intelligent obstacle avoidance ability in the current indoor delivery robot operation process, this paper takes ROS combined with YOLOv8 as the intelligent driving core, uses the A* algorithm to make the robot go to the target position, plan a reasonable route, take STM32 as the intelligent control core, and use the Mecanum wheel as the power take-off wheel. Based on this, an indoor delivery robot based on ROS and the McNum wheel motion scheme is designed. This paper designs the robot as a whole, designs the mechanical structure and functional modules of the robot, and simulates and analyzes the obstacle avoidance scheme and key functions of intelligent driving. Experiments have proved that the design of the delivery robot can not only achieve efficient and accurate distribution, but also reduce energy consumption to a certain extent, and provide new ideas for the intelligent transformation and development of the logistics industry.

Visual-Motor Coordination While Drifting Through the Corner of an Ice-Racing Track: A Case Study of an Expert and a Novice Driver

This case study investigated the visual-motor coordination of an expert and a novice driver during high-speed cornering on an ice-racing track. The frozen track imposes unique task constraints on drivers due to the loss of traction. We Examined the coordination structure employed by the drivers to stabilize task goals in such an uncertain environment. The eye tracker system collected data on eye movements, head rotation, and steering wheel rotation. Coherent patterns of eye-head-steering were evaluated through Mutual Information with a time delay. The results showed that both drivers were forced to deal with unstable, shaky steering under the task constraints of losing traction. The novice driver employed a control strategy that suppressed both head and steering wheel movements. The expert driver exhibited rhythmic head rotation, which may have a functional role in dealing with disturbances by generating stable movement patterns. This study highlights human flexibility and adaptability in response to challenging and uncertain environments. The perception-action system of the expert driver actively generated movements, forming a functional and complementary coordination.

Application of Continuous Stability Control to a Lightweight Solar-Electric Vehicle Using SMC and MPC

This paper investigates the application of contusion stability yaw control of a lightweight solar-electric vehicle. The vehicle’s customized design envelope makes it more sensitive to variations in load due to its low weight and relatively large size. To address this issue, control strategies were developed using differential motor torques to generate direct yaw moments using the vehicle’s rear in-wheel motors. This paper introduces the working conditions of solar vehicles and demonstrates the necessity of stability control. Vehicle parameters such as mass and center of gravity position are obtained to apply control to the real vehicle. The paper then describes two stability control strategies, using (i) sliding-mode control (SMC) and (ii) model predictive control (MPC). To account for the road bank angle of the test area and the impact of additional weight from a driver and passenger, a Kinematic-Based Observer is designed to estimate the vehicle’s side-slip based on measured values. To collect real-time data, a dSPACE MicroAutobox was installed on the solar vehicle. The results show the effect of the observer and controllers under different vehicle speeds and load conditions. Finally, closed-loop simulation results are presented to support the findings from the open-loop testing.

Multi input multi output lateral dynamics control of an electric vehicle

Full electric vehicles with multiple and independently controlled powertrains allow for an improvement of vehicle handling capabilities both in steady state and in transient manoeuvres. This paper focuses on active lateral dynamics control of an electric vehicle equipped with 4 in-wheel motors and active rear steering. An integral terminal sliding mode controller (ITSMC) is derived starting from the linearized single track model with the addition of the rear wheel steering angle. The controller has a multi-input multi-output structure and is designed to track vehicle yaw rate and sideslip angle reference quantities through torque vectoring and active rear steering actuation. A novel approach for calculating reference sideslip angle and yaw rate using a logistic function is also presented in this paper. The ITSMC relies on real time knowledge of sideslip angle which cannot be measured in the real vehicle, thus it is estimated through the addition of an extended Kalman filter to the control loop. The performance of the controller is tested with VI-CarRealTime 14 degrees of freedom nonlinear model both for steady state and transient manoeuvres. Simulation results show a good tracking of the reference value with no chattering issues and with an improved behaviour if compared to a sliding mode controller from literature.

Fixed-time anti-disturbance constraint fuzzy synchronization control for PMSM based four-wheel-independent-drive EVs

A fixed-time anti-disturbance constraint fuzzy synchronization control method is proposed, for the sake of solving the problem of fast recovery of synchronization between in-wheel permanent magnet synchronous motors (PMSMs) in four-wheel-independent drive electric vehicles. The system model of in-wheel PMSM is presented in the beginning, and fuzzy logic systems are used for approximating the uncertainty parts of the PMSM model. Based on the PMSM model, a fixed-time disturbance-observer is designed to account for fast estimation of fluctuating load torque. Then, the neighborhood synchronization error is constructed based on a directed-graph, and a performance function is designed to guarantee the neighborhood synchronization error evolves strictly within the prescribed bound. Besides, the fixed-time bound of all signals is proved. Finally, the hardware-in-the-loop platform is built, and the electronic differential and the nonlinear vehicle model are employed to validate the advanced performance of the design control method.