Road Test Results Research Articles

A Tracking System of Multiple LiDAR Sensors Using Scan Point Matching

We address a tracking system of 360° field of view using Light Detection And Ranging (LiDAR) sensors, which are a key module for detecting surrounding traffic and infrastructure for vehicular safety applications. We propose a joint algorithm for estimating motion and a nonparametric contour model whose complexity is O(N), with N being the number of scan points. Particularly, the proposed nonparametric model has the potential to track objects with arbitrary shape (e.g., car, pedestrian, and bicycle). A comparison of the proposed approach with other methods using parametric models shows the robustness and the quality of the proposed system. Quantitative performance evaluation against ground truth is presented in tracking a car, a pedestrian, and a bicycle. Experiments demonstrate that the proposed system substantially improves performance. Road test results show the effectiveness and efficiency of the implemented system. A lane-change alert (LCA) demonstration system is built based on the detection system, and the LCA performance is analyzed using ground truth.

Center of gravity height real-time estimation for lightweight vehicles using tire instant effective radius

Center of gravity (CG) height is an important parameter for lightweight vehicles (LWVs). Because of the inherently smaller weight and size, a LWV's CG height is more easily affected by loading conditions compared with conventional vehicles. This paper proposes a novel tire instant effective radius (TIER) method for real-time estimation of the CG height for LWVs. The method utilizes the mathematical correlation between the tire vertical load transfer that is proportional to the CG height, and the TIER variation. A Kalman filter based estimator is designed to simultaneously identify the vehicle CG height as well as the unknown nominal tire effective radius. To verify the performance of the proposed estimator, simulation results are first provided for several vehicles with different CG heights, and then road test results obtained on a lightweight electric ground vehicle (EGV) equipped with an advanced measurement system are given. Both simulation and experimental results show that the developed estimator is capable of providing an accurate estimation of the vehicle CG height in real-time.

Algorithm Improvement of the Low-End GNSS/INS Systems for Land Vehicles Navigation

Recent advances in MEMS IMUs give the potential to develop affordable low-end GNSS/INS systems for land vehicles navigation (LVN). To improve the performance of low-end GNSS/INS systems, we made detailed quantitative analysis to the computation terms of the INS navigation equation in regard to accuracy impacts and computation loads and then proposed a simplified INS algorithm and adjusted the corresponding Kalman filter of GPS/INS integration. Comprehensive analysis was made to get the quantitative impacts of each simplified term. Results of road test have shown that the degradation of the navigation accuracy caused by the algorithm simplification was much less than that caused by the sensors errors of the MEMS IMU. Meanwhile, the computation load could be reduced by 70% with the simplified algorithm, and the reduction can go further to reach nearly 95% by downsampling IMU data rate simultaneously. Therefore, it is feasible to simplify the INS algorithm without losing accuracy and get benefits of reducing the computation load, which can further enhance the real-time performance of the navigation. The work has special significance for the applications that have limited processor resource and request strict real-time response, such as a deeply coupled GPS/INS receiver.

A Driver Modeling Based on the Preview-Follower Theory and the Jerky Dynamics

Based on the preview optimal simple artificial neural network driver model (POSANN), a new driver model, considering jerky dynamics and the tracing error between the real track and the planned path, is established. In this paper, the modeling for the driver-vehicle system is firstly described, and the relationship between weighting coefficients of driver model and system parameters is examined through test data. Secondly, the corresponding road test results are presented in order to verify the vehicle model and obtain the information on drive model and vehicle parameters. Finally, the simulations are carried out via CarSim. Simulation results indicate that the jerky dynamics need to be considered and the proposed new driver model can achieve a better path-following performance compared with the POSANN driver model.

Effective energy regeneration from multi-mode-based vehicle vibration

In recent years, energy harvesting technologies using renewable energy have been focused. This paper presents a novel vibration power generation device for vehicles where effective power generation can be obtained by multi-mode vibration of the vehicles. The main advantage of the developed device is the power generation over wide frequency range. First, road tests of the vehicle are performed for several representative conditions such as mass and velocity variations, and then the obtained data is analysed. Next, a vibration power generation device specially designed for the vehicle is proposed. This new device is composed of the multiple masses and spring plates equipped with a lead zirconate titanate (PZT), and is effective in multi-mode vibration. Taking the road-test results into consideration, the design is carried out based on agreement between the resonant frequencies of the device and the vibration frequencies of the vehicle. The validity of the developed device is confirmed by the simulation and experimental results.

Research on Shifting Control Method of Positive Independent Mechanical Split Path Transmission for the Starting Gear

To realize a smooth and quick shift of the positive independent mechanical split path transmission (PIMSPT) equipped with automatic shifting control system (ASCS), the research on the feasibility of improving shift quality by dynamic and cooperative controlling engine, steering clutches, and brakes has been conducted. The shifting control method suited to starting gear of PIMSPT has been proposed. The control method is based on control parameters, such as the driving shaft speed and its derivative. The control laws of steering clutches and brakes are presented during each gear and stage of shifting. Bench and road test results show that the proposed shifting control method can not only shorten the shift time, but also decrease the jerk of shifting effectively.

A reconfigurable structure electronic commutator for a dual BLDC motor EV drive

Abstract An electronic commutator that can drive a PM BLDC motor either in the full bridge or half bridge configuration has been developed. This commutator allows increasing the motor speed over the nominal value, hence the motor is able to operate within a wide constant power speed range. An application of the commutator with a reconfigurable structure for the double drive of a small electric vehicle Elipsa has been presented. The driveline consists of two independent commutators feeding the motors coupled by gears with rear wheels of the vehicle. Both commutators are controlled by a common control system based on a signal microcontroller. The results of road tests indicate new areas of BLCD motor drives application. The fact that the BLCD motor work in the second speed range does not require any changes in the motor construction and at the same time does not significantly deteriorate the drive efficiency is an indisputable advantage of the presented solution

Map Matching-Aided In-Motion SINS Initial Alignment

The paper introduces a novel in-motion SINS initial alignment algorithm using the inertial frame as computing reference. First, dead reckoning method is utilized with the help of the external odometer speed information aiming to eliminate the angular and linear moving disturbances. Second, in order to suppressing the divergence of the positioning error, a new integrated Map Matching algorithm is introduced which is able to reduce the effect of misalignment angle from coarse alignment for positioning error. Road test results show that this algorithm has greatly reduced the coarse alignment of directional accuracy and saved the requirements of speed and route for land vehicles. Not only is the mobility of land vehicle enhanced but also the accuracy of initial alignment of inertial navigation system is improved, which is meaningful in real application.

Cooperative control of regenerative braking and hydraulic braking of an electrified passenger car

With the aims of regeneration efficiency and brake comfort, three different control strategies, namely the maximum-regeneration-efficiency strategy, the good-pedal-feel strategy and the coordination strategy for regenerative braking of an electrified passenger car are researched in this paper. The models of the main components related to the regenerative brake and the frictional blending brake of the electric passenger car are built in MATLAB/Simulink. The control effects and regeneration efficiencies of the control strategies in a typical deceleration process are simulated and analysed. Road tests under normal deceleration braking and an ECE driving cycle are carried out. The simulation and road test results show that the maximum-regeneration-efficiency strategy, which causes issues on brake comfort and safety, could hardly be utilized in the regenerative braking system adopted. The good-pedal-feel strategy and coordination strategy are advantageous over the first strategy with respect to the brake comfort and regeneration efficiency. The fuel economy enhanced by the regenerative braking system developed is more than 25% under the ECE driving cycle.

The Layout of Strain Sensor Based on the Preanalysis Load Distribution

In this paper, the load distribution of the rear axle of a MPV is preanalyzed, by using the finite element analysis method, which obtains the contour and the strain tensor maps in the four working conditions of the rear axle: static load, braking, steering and torsion. By analyzing the contour and strain tensor maps, the key load locations and their main stress direction is identified. Through processing data of the calibration tests, the equations of linear regression between load and strain on the rear axle are determined.Comparing with the real 5vehicle road test results, the placement locations of the sensor on the rear axle, which is determined through the finite element analysis, are verified to be correct.

Design and implementation of a hybrid electric motorcycle management system

This paper presents a successful design and implement of a shunt-winding hybrid electric motorcycle management system which utilizes an electronic control unit (ECU) to integrate two major subsystems together, one being the traditional system of 125 c.c. internal combustion engine and the other an electric power motor. The hybrid electric motorcycle is assembled together robustly by these two major subsystems and eventually leads to successful road tests. The hybrid power system thus implemented can recharge its own batteries with electricity provided by the electrical recharge system and thus increasing the cruising mileages largely. The testing results obtained by using the proposed experimental platform indicate that lead-acid cells can boost their state of charge (SOC) by approximately 4% when it is operated under the hybrid mode for four driving cycles (about 1600 s) with the recharger on in a standard ECE-40 testing procedure. The results of road tests also clearly show that the pollutant emissions of the engine can be reduced at a lower speed or idling condition, and the problem of insufficient cruising range for electric motorcycles can also be greatly enhanced.

Vibrational protection provided by automobile suspensions with both hydraulic and inertial-frictional shock absorbers

A mathematical model is used to investigate automobile suspensions with both hydraulic and inertial-frictional shock absorbers. The optimal parameters of this combined damping system are determined for the suspension of the GAZ-66 vehicle. A prototype inertial-frictional shock absorber is described, and the results of road tests on the Gazel ambulance are presented.

DriveWise: An Interdisciplinary Hospital-Based Driving Assessment Program

ABSTRACT Health care professionals working with the elderly have opportunities through research and clinical practice to shape public policy affecting the older driver. This article describes DriveWise, an interdisciplinary hospital-based driving assessment program developed in response to clinical concerns about the driving safety of individuals with medical conditions. DriveWise clinicians use evidence-based, functional assessments to determine driving competence. In addition, the program was designed to meet the emotional needs of individuals whose driving safety has been called into question. To date, approximately 380 participants have been assessed through DriveWise. The following report details the DriveWise mission, DriveWise team members, and road test results. We continue to refine the assessment process to promote safety and support the dignity and independence of all participants. The DriveWise interdisciplinary approach to practice is a concrete example of how gerontological education across professions can have direct benefits to the older adult.

Experimental investigation of tyre dynamics by means of MEMS accelerometers fixed on the liner

Nowadays, many researches exist in the automotive field aimed at improving vehicle active control. Recently, the possibility to exploit sensors fixed inside the tyre (particularly on the liner) has been presented by the authors of this paper [F. Braghin, M. Brusarosco, F. Cheli, A. Cigada, S. Manzoni, and F. Mancosu, Measurement of contact forces and patch features by means of accelerometers fixed inside the tyre to improve future car active control, Vehicle Syst. Dyn. 44(1) (2006), pp. 3–13]. These sensors allow measurements to be obtained from the closest point to the contact patch, making possible the best description of contact phenomena (with respect to the actual situation in which sensors are usually placed on the hub); these data can be sent to the vehicle controller, processed and therefore used for active control. However, there is still a tyre layer between the sensors and the road, therefore a specific study of the transfer functions between tyre input and sensor signals is needed to understand how to correlate signal trends to physical events, taking into account tyre behaviour. This also means that signal features have to be analysed to find how they depend on physical parameters (such as vertical load, camber angle, etc.). A dedicated test facility has been designed and built to perform this task; this is the object of the present paper, which first of all focuses on the choices for this particular design solution. Different tyres have been tested by means of this test bench (the study has been carried out up to 2 kHz and this threshold comes from road test results), looking for eventual differences among their behaviours; in particular, the effects of tyre tread block presence have been investigated.

Rubber Abrasion and Tire Wear

Abstract Rubber abrasion is essentially a mechanical tearing process and has been linked with the rate of a cut growth process as function of the tearing energy dissipated in the contact area between rubber and track which leads inevitably to considerable temperature rises at the points of highest stress concentration i.e. at the points at which a mechanical detachment of abraded particles is most likely. This leads to thermal degradation and oxidation as important secondary mechanisms which may well decide whether a compound performs better or worse than a reference outweighing the mechanical properties. A laboratory method has been developed, using the LAT 100 test equipment, which uses the energy dissipation and slip speeds in the contact area of a rubber sample wheel, rotating under slip, to evaluate the abrasion performance of a compound over a wide range of these variables. The resulting equations can be used either to test directly the correlation between laboratory and road test results which is usually good over a limited range, or they are used in a road test simulation program with well defined road test conditions. The latter gives a set of single compound ratings and tire lives. These depend however strongly on the chosen test conditions and in that they reflect reality

Road test evaluation of vibration control performance of vehicle suspension featuring electrorheological shock absorbers

This work presents road test results for vibration control of a vehicle suspension system equipped with continuously controllable electrorheological (ER) shock absorbers. The test vehicle is a mid-sized passenger car whose suspension systems are typical Macpherson strut types for the front part and multilink types for the rear part. The four ER shock absorbers (two for the front suspension and two for the rear suspension) are devised based on design specifications for the test vehicle and their damping forces are experimentally evaluated with respect to the electric field. The ER shock absorbers and conventional spring elements are then assembled into suspension systems. Prior to undertaking the road test, the front ER suspension is applied to the quarter-car facility in order to validate control performance of the skyhook controller embedded in on-chip hardware. Subsequently, the full-vehicle model incorporating four ER suspensions is established and the skyhook control gains are determined in an optimal manner. The controller is then implemented on the test vehicle which is equipped with several sensors, a data acquisition system, and high-voltage amplifiers. Control performances are evaluated under various road conditions (bump, long waved, rugged, paved, and unpaved) and presented in both time and frequency domains.

POSSIBILITIES OF DRIVEABILITY AND FUEL CONSUMPTION IMPROVEMENT BY ADVANCED CONTROL POWER TRANSMISSION SYSTEM IN PASSENGER CAR

The correct work of a power transmission system for the sake of a car motion properties, fuel consumption and pollution emission, requires proper control of an engine and power transmission system. This problem becomes especially significant in the case of automation of the power transmission system and particularly regarding the system of constant gear ratio change between the engine and drive wheels (Continuously Variable Transmission), examined in the paper. This control is based on friction degree conditions estimation between metal belt and the transmission wheels. This paper also describes the experimental results of bench test and road test and applying of different control strategies.

Idling-stop vehicle road tests of advanced valve-regulated lead-acid (VRLA) battery

The results of road tests on valve-regulated lead-acid (VRLA) batteries in an idling-stop (stop and go) vehicle are reported. Idling-stop systems are simple systems to improve fuel economy of automobiles. They are expected to spread widely from an environmental perspective. Performances of a conventional flooded battery, a conventional VRLA battery, and an improved VRLA battery were compared in road tests with an idling-stop vehicle. It was found that the improved VRLA battery was suited to idling-stop applications because it had a smaller capacity loss than the conventional flooded battery during partial-state-of-charge (PSoC) operation. The positive grid was corroded in layers, unlike the usual grain boundary corrosion of SLI battery grid. It is because the corrosion proceeded mainly under PSoC conditions. The corrosion rate could be controlled by potential control of positive plates.

Influence of rubber compound and tread pattern of retreaded tyres on vehicle active safety

The aim of the article is to present the results of road tests of original and retreaded tyres, analysed in the aspect of vehicle active safety. The tests covered emergency braking, steady-state circular tests and severe lane-change manoeuvre. The tests were performed in summer and winter conditions. Original Michelin tyres and Michelin tyres retreaded with summer and winter rubber compounds were used. The results of the tests proved that vehicle active safety is affected by retreaded tyres. The differences between braking deceleration of a car with original tyres and braking deceleration of a car with retreaded tyres confirmed the necessity of performing braking tests on the place of accident with the set of tyres with which the vehicle participating in the accident was equipped.

The dynamics of the acceleration of a car fuelled with petrol and CNG

In this publication presented are the results of road tests of a passenger car fuelled alternatively with petrol and IV generation CNG. Described are the design of an engine fuelling system and the methodology of testing. Compared are the obtained results and evaluated is the influence of the type of fuel on the dynamics of car acceleration.