Rear Motor Research Articles

Analysis of a Quadcopter’s Acoustic Signature in Different Flight Regimes

This paper presents a detailed analysis of quadcopter noise emitted in different flight regimes and suggests an innovative approach to quadcopter sound detection. Currently, quadcopters have become extremely popular and are used for various applications. In some case scenarios, these applications are not legal; therefore, they represent a threat, and early detection of quadcopters becomes imperative. However, conventional detection with radars and infrared cameras does not provide satisfactory results, since some quadcopters have relatively small dimensions, and their motors have low heat emissions. Thus, this paper focuses on the noise emitted by quadcopters, which is connected to the changing revolutions per minute of the electric quadcopter motors. Thus, the paper connects the unique quadcopter features with the emitted sounds, which can be used for detection in different acoustic environments. The suggested algorithm uses signal processing with a nonlinear function, which results in new spectral lines that correspond to rotational speed differences between the front and rear motors. The analysis shows that the processed signal mixed with a traffic noise signal can be detected when the level reaches 3 dB lower than the level of the surrounding noise.

Fault-Tolerant Stability Control for Independent Four-Wheel Drive Electric Vehicle Under Actuator Fault Conditions

Various torque distribution and stability control algorithms have been studied along with the development of four-wheel drive vehicles. But, most of those algorithms focus only on performance improvement. Since the independent four-wheel drive system is based on four drive motors, faults can occur in a motor or an inverter. If a fault occurs, the vehicle stability is not guaranteed and a fatal accident can occur. In this study, the fault-tolerant stability control algorithm for remaining healthy motors is proposed. This fault-tolerant control (FTC) system contains torque distribution and stability control algorithms. For accurate control of motor allocation, driving conditions such as under/over-steering, and steering direction should be considered, as well as vehicle condition such as fault motor location and motor performance limits. The proposed FTC is evaluated with two fault conditions (e.g., front motor fault, rear motor fault) under straight acceleration and constant steering acceleration scenarios. The behavior characteristics and driving risks caused by failures of motors while driving are analyzed. Also, the FTC algorithm is accurately follow a desired path within a minimum error range that the driver can cover.

Exploration of Optimal Powertrain Design Using Realistic Load Profiles

The electrification of bus-based public transportation contributes to the goal of reducing the adverse environmental impacts caused by urban transportation. However, the penetration of electric vehicles has been slow due to their lower vehicle range and total costs in comparison to vehicles driven by internal combustion engines. By improving the powertrain efficiency, the total costs can be reduced for the same vehicle range. Therefore, this paper proposes a holistic design exploration approach to investigate and identify the optimal powertrain concept for electric city buses based on the component costs and energy consumption costs. The load profiles of speed, slope, and passenger occupancy profiles are derived for a selected bus route in Singapore, which is used in a powertrain design exploration for a 30-passenger vehicle. Six different powertrain architectures are analyzed, together with single and multi-speed gearbox configurations, to identify the optimal powertrain architecture and the resulting component sizes. The powertrain configurations are further analyzed in terms of their influence on the vehicle characteristics and total costs. Multi-motor configurations were found to have better vehicle characteristics and lower total costs in comparison to single rear motor configurations. Concepts with motors on the front and a rear axle could shift the load points to a higher efficiency region, resulting in lower energy consumption and energy costs. The optimal powertrain concept was a fixed-speed two-motor configuration, with a booster motor on the front axle and a motor on the rear axle.

Automatic motor speed reference generators for cruise and lateral control of electric vehicles with in-wheel motors

Motor speed reference generators have been recently presented in the literature for the cruise control of electric vehicles powered by centralized electric motors. Steady-state operation at a safe tire longitudinal slip is guaranteed to be achieved in the presence of uncertain external conditions. In this paper, a generalization of the aforementioned result to electric vehicles that make use of two in-wheel motors and are required to perform a bend manoeuvre is provided. A new cruise and lateral control is presented. The two in-wheel rear motors provide propulsion, while being capable of acting as a rear differential. The key point relies on the definition of suitable references for the two motor speeds, so that motor speed control algorithms can be directly inherited from the electric machine control literature, while intrinsically robust motor speed control loops can be additionally incorporated. Both CarSim simulations and experiments are included to illustrate the practical effectiveness of the proposed approach.

Development of Braking Force Distribution Strategy for Dual-Motor-Drive Electric Vehicle

In the development of the optimal braking force distribution strategy for a dual-motor-drive electric vehicle (DMDEV) with a series cooperative braking system, three key factors were taken into consideration, i.e. the regenerative force distribution coefficient between the front and the rear motor ( β ), the energy recovery coefficient at the wheels ( α 3 ), and the front-and-rear-axle braking force distribution coefficient ( λ ). First, the overall power loss model of the two surface-mounted permanent magnetic synchronous motors (SMPMSMs) was created based on the d-q axis equivalent circuit model. The optimal relationship of β and the overall efficiency of the dual-motor system were confirmed, where the latter was quite different from that obtained from the traditional look-up table method for the motors’ efficiency. Then, four dimensionless evaluation coefficients were used to evaluate braking stability, regenerative energy transfer efficiency, and energy recovery at the wheels. Finally, based on several typical braking operations, the comprehensive effects of the four coefficients on braking stability and energy recovery were revealed. An optimal braking force distribution strategy balancing braking stability and energy recovery is suggested for a DMDEV with a series cooperative braking system.

Autonomy and User Experience Enhancement Control of an Electrically Assisted Bicycle With Dual-Wheel Drive

This paper presents a control strategy study of a dual-wheel drive electric bicycle by taking the human–bicycle coupling into consideration. Containing two electric motors (one on the hub of each wheel), the bicycle is controlled by a fuzzy controller, which ensures a sharing of the total power between the front and rear motors. The goal of this paper is to develop a control method for an electric bicycle with regenerative braking and dual-wheel drive. The proposed method can achieve a better user experience (response time and speed control) than the one currently proposed to the market. The two motors are controlled by two separate torque references and the control algorithm is carefully designed in order to consider the coupling between human reaction time and motor driving response time. In addition, both wheels are equipped with kinetic energy recovering breaks allowing an increased autonomy. The developed controller also has the ability to adapt different road conditions, in the objective of user experience improvement and power saving.

Optimal power distribution of front and rear motors for minimizing energy consumption of 4-wheel-drive electric vehicles

In this paper, the optimal power distribution of the front and rear motors for minimizing energy consumption of a 4WD EV is investigated. An optimal power distribution control is developed based on the mathematical energy consumption model of an EV. The objective function is defined while ignoring time. And, the time effect is applied by considering the objective function for every single driving point which consists of the vehicle driving force and velocity. From the optimization problem, the optimal torque distribution maps of the front and rear motors can be obtained for all vehicle driving force and velocity ranges. These maps can be expressed using a 3-dimensional map. If the vehicle driving force and velocity are determined, the optimal front and rear motor torques can be determined using these maps. These maps can distribute the front and rear motor torques for the entire velocity range. Thus, these maps can perform the optimal power (torque times speed) distribution of the front and rear motors for minimizing the energy consumption of the 4WD EV. The performance of the optimal power distribution is evaluated by comparing the energy consumption to that of simple power distribution control. For obtaining the energy consumption, a vehicle driving simulation is performed. For the simulation, the driving cycle is required, and the NEDC (New European Driving Cycle) is used. From the simulation results, it is found that the energy consumption of simple power distribution is 4.8 % larger than the optimal one. Thus, the optimal power distribution can minimize the 4WD EV energy consumption as the optimization objective function.

High order sliding mode control for hybrid vehicle stability

This paper tackles the problem of driving stability for a hybrid vehicle. A rear electric motor has been added to the vehicle driveline and the positive/negative torque generated by this motor affects the driving conditions. The vehicle stability control is addressed using high order sliding modes (HOSMs) control and observation techniques. Two cases are studied: yaw stability and traction control. The proposed controllers preserve the system’s safety under undesirable rear motor effects, at the same time, they cope with vehicle uncertainties. The feasibility of this platform was tested in a vehicle simulator.

PD-fuzzy Control of a Stair Climbing Wheelchair

This paper focuses on the development of a control strategy of a compact stair climbing wheelchair to maintain stable and balance while negotiating staircases in confined spaces for the elderly and disabled. The Visual Nastran 4D is used to develop a simulation models and linked with Matlab platform for control and visual assessment purposes. The challenges are to control front and rear motors as well as tilt angle to ensure system stability and maintain smoothness of the climbing process. PD-Fuzzy controls are developed, tested and associated performances are assessed through intensive visual approach.

Flight PID controller design for a UAV quadrotor

This paper presents the modeling of a four rotor vertical take-off and landing (VTOL) unmanned air vehicle known as the quad rotor aircraft. The paper presents a new model design method for the flight control of an autonomous quad rotor. The paper describes the controller architecture for the quad rotor as well. The dynamic model of the quad-rotor, which is an under actuated aircraft with fixed four pitch angle rotors was described. The Modeling of a quad rotor vehicle is not an easy task because of its complex structure. The aim is to develop a model of the vehicle as realistic as possible. The model is used to design a stable and accurate controller. This paper explains the developments of a PID (proportional-integral-derivative) control method to obtain stability in flying the Quad-rotor flying object. The model has four input forces which are basically the thrust provided by each propeller connected to each rotor with fixed angle. Forward (backward) motion is maintained by increasing (decreasing) speed of front (rear) rotor speed while decreasing (increasing) rear (front) rotor speed simultaneously which means changing the pitch angle. Left and right motion is accomplished by changing roll angle by the same way. The front and rear motors rotate counter-clockwise while other motors rotate clockwise so that the yaw command is derived by increasing (decreasing) counter-clockwise motors speed while decreasing (increasing) clockwise motor speeds. Key words: Quadrotor, proportional-integral-derivative (PID) controller, vertical take-off and landing (VTOL), unmanned aerial vehicles (UAV), MATLAB / Simulink.

퍼지 슬라이딩 모드를 이용한 4WD 하이브리드 차량의 선회성능 향상

A new Fuzzy sliding mode controller is proposed to improve the cornering performance of the four wheel hybrid vehicles. The Fuzzy sliding mode control is applied for the control of rear motor and EHB (Electro-Hydraulic Brake) to improve the cornering performance. The modeling of the automobile is simplified that each of the two wheels is modeled as two degrees of freedom object and the friction coefficient between the wheel and the ground is assumed to be constant. The output of the Fuzzy sliding mode algorithm is the direct yaw moment for the rear wheels, which compensates for the slip angle. Through the simulations using ADAMS and MATLAB Simulink, the cornering performance of the proposed algorithm is compared to the conventional PID to show the superiority of the proposed algorithm. In the simulation experiments, the J-Turn and single lane change are used for each of the Fuzzy sliding mode algorithm and PID controller with the optimal gains which are tuned empirically.

Vehicle Stability Enhancement of Four-Wheel-Drive Hybrid Electric Vehicle Using Rear Motor Control

A vehicle stability enhancement control algorithm for a four-wheel-drive hybrid electric vehicle (HEV) is proposed using rear motor driving, regenerative braking control, and electrohydraulic brake (EHB) control. A fuzzy-rule-based control algorithm is proposed, which generates the direct yaw moment to compensate for the errors of the sideslip angle and yaw rate. Performance of the vehicle stability control algorithm is evaluated using ADAMS and MATLAB Simulink cosimulations. HEV chassis elements such as the tires, suspension system, and steering system are modeled to describe the vehicle's dynamic behavior in more detail using ADAMS, whereas HEV power train elements such as the engine, motor, battery, and transmission are modeled using MATLAB Simulink with the control algorithm. It is found from the simulation results that the driving and regenerative braking at the rear motor is able to provide improved stability. In addition, better performance can be achieved by applying the driving and regenerative braking control, as well as EHB control.

Optimal brake torque distribution for a four-wheeldrive hybrid electric vehicle stability enhancement

Vehicle stability control logic for a four-wheel-drive hybrid electric vehicle is proposed using the regenerative braking of the rear motor and an electrohydraulic brake (EHB). To obtain the optimal brake torque distribution between the regenerative braking and the EHB torque, a genetic algorithm is used. The genetic algorithm calculates the optimal regenerative braking torque and the optimal EHB torque for the given inputs of the desired yaw moment and road friction coefficient. Based on the optimal brake torque distribution, the vehicle stability control logic proposed generates the desired direct yaw moment to compensate the errors of the side-slip angle and yaw rate by a fuzzy control algorithm corresponding to the driver's steering angle and vehicle velocity. Performance of the vehicle stability control logic is evaluated by comparison of the fixed regenerative braking and the optimal regenerative braking for a single lane change manoeuvre. It is found from the simulation results that the optimal regenerative braking is able to provide the increased recuperation energy compared with the fixed regenerative braking while satisfying the vehicle stability.

Advanced Active Safety System Using Separated Front and Rear Motor Control for a 4WD Hybrid Electric Vehicle

Vehicle stability in 4 wheel drive(4WD) vehicles has been pursued by torque split based technology and brake based technology. The brake based methods are essentially brake maneuver strategies using the active control of the individual wheel brake. By comparison, the torque split based technologies realize stability by varying the traction torque split through powertrain to create an offset yaw moment. In the 4WD hybrid electric vehicle adopting separate front and rear motor, the vehicle stability enhancement algorithm using the rear motor control has some advantages such as faster response, braking energy recuperation, etc. However, since the left and right wheels are controlled by the same driving and regenerative torque from one motor, stability enhancement only by the front and rear motor control has a limitation in satisfying the required offset yaw moment. Therefore, to obtain the demanded offset yaw moment, a brake force distribution at each wheel is required. In this paper, a vehicle stability control logic using the front and rear motor and electrohydraulic brake(EHB) is proposed for a 4WD hybrid electric vehicle. A fuzzy control algorithm is suggested to compensate the error of the sideslip angle and the yaw rate by generating the direct yaw moment. Performance of the vehicle stability control algorithm is evaluated using ADAMS and MATLAB Simulink co-simulation.

Vehicle Stability Control with Regenerative Braking and Electronic Brake Force Distribution for a Four-Wheel Drive Hybrid Electric Vehicle

Vehicle stability control for a four-wheel drive (4WD) hybrid electric vehicle is investigated using the regenerative braking of the rear motor and electrohydraulic brake (EHB). A fuzzy-rule-based control algorithm is proposed, which generates the direct yaw moment to compensate for the errors of the sideslip angle and yaw rate. Performance of the stability control logic is evaluated for J-turn and single-lane change. It is found from the simulation results that the regenerative braking of the rear motor is able to provide improved stability compared with the vehicle performance without any control. It is found that better performance can be achieved by applying the regenerative braking plus the EHB control. In addition, the optimal distribution ratio of the EHB force is presented to minimize the EHB power consumption. The simulation results show that the required torque level by the optimal EHB distribution ratio control is much lower than that of the fixed distribution ratio, while providing almost the same control performance. It is expected that the vehicle stability control algorithm suggested in this study is able to offer improved vehicle stability.

Increasing the Speed of a Lateral Guided Vehicle with a Sensor Steering Mechanism Using 1kHz Intelligent Camera(Drift Control by Changing of Steering and Arm Length Ratio)

The previous paper proposed a SSM (Sensor Steering Mechanism) for a lateral guided vehicle which follows the guideway. The SSM achieves high-speed moving on a straight line, but the cornering stability is influenced by the approach speed and the slip angle of the tires. For the conventional SSM, the steering ratio (the ratio of a sensor arm angle and a steering angle) is set at 2 to 1. In order to reach high speeds while moving, this paper proposes the variable steering ratio and the sensor arm ratio (the ratio of the sensor arm length and the wheel base). For the experiment, the steering ratio of the RR (Rear motor Rear drive) type SSM vehicle with 1 kHz smart camera is changed to 1 to 1.5. Experimental and simulated results of running on the test track are presented and demonstrated the advantage of this method.

Drift Turning of Lateral Guided Vehicle with Sensor Steering Mechanism. Application of a Variable Kinetic Friction Model.

In the previous paper, the simulated loci of high speed cornering are not correspond with the experimental results, because of the tire model is only used the sticking in Coulomb friction model. If the centrifugal force becomes larger than the cornering force of tires, the vehicle does not maintain the desired course. This demeanor includes the sticking and slipping condition of the tire. In order to simulate the trajectory at the high speed corner, this paper is assumed three stages of friction condition; the low kinetic friction force at the beginning of slipping, the period of kinetic friction force, and returning to the static friction at the small slip angle. In addition of the RR (Rear motor Rear drive) type vehicle, FF (Front motor Front drive) type with SSM (Sensor Steering Mechanism) and four-wheel steering mechanism is developed, and both robots run on the oval course at high speed. Numerical simulation and experimental results show the effectiveness of the presented friction model.

Vibroisolating apparatus of vacuum cleaner

The present invention relates to a vibroisolating apparatus for a vacuum cleaner adapted to absorb and inhibit the vibrations generated in a suction motor from being transmitted to a body of the vacuum cleaner to thereby reduce the noise resulting from the vibration to a minimum, and at the same time, to improve the ease of assembling and to decrease manufacturing cost by way of a simplified construction. The vibration generated in the suction motor during operations is absorbed and inhibited at a front side of the motor by a vibroisolating ring which is tightly disposed between a front motor case and the suction motor. The vibration is also absorbed and inhibited at a rear side of the motor by the rear surface packing which is disposed between a rear motor case and the motor. The apparatus thereby reduces generation of noise resulting from the vibration of the suction motor to a minimum and provides for relatively silent operation of the vacuum cleaner.