Actual Vehicle Test Research Articles

Model Predictive Idle Speed Control: Design, Analysis, and Experimental Evaluation

Idle speed control is a landmark application of feedback control in automotive vehicles that continues to be of significant interest to automotive industry practitioners, since improved idle performance and robustness translate into better fuel economy, emissions and drivability. In this paper, we develop a model predictive control (MPC) strategy for regulating the engine speed to the idle speed set-point by actuating the electronic throttle and the spark timing. The MPC controller coordinates the two actuators according to a specified cost function, while explicitly taking into account constraints on the control and requirements on the acceptable engine speed range, e.g., to avoid engine stalls. Following a process proposed here for the implementation of MPC in automotive applications, an MPC controller is obtained with excellent performance and robustness as demonstrated in actual vehicle tests. In particular, the MPC controller performs better than an existing baseline controller in the vehicle, is robust to changes in operating conditions, and to different types of disturbances. It is also shown that the MPC computational complexity is well within the capability of production electronic control unit and that the improved performance achieved by the MPC controller can translate into fuel economy improvements.

Study on soft computing arithmetic for vehicle yaw rate based on ANFIS

A soft computing arithmetic based on Adaptive Neuro-Fuzzy Inference System (ANFIS) is proposed to estimate vehicle yaw rate in a driver-vehicle closed loop system, and vehicle yaw rate is considered as a nonlinear mapping of time series of rack displacement and lateral acceleration. Simulation study on soft computing of vehicle yaw rate in the driver-vehicle closed loop system is conducted, and the performance of the soft computing arithmetic based on ANFIS is evaluated with the help of actual vehicle test data. Results indicate that the generalisation of the soft computing arithmetic based on ANFIS is better than that based on Radial Basis Function (RBF) neural network.

A driver model for vehicle lateral dynamics

There have been several studies aiming to develop a realistic driver model in accordance with the increased interest in vehicle safety issues and in computer simulation for a vehicle design. This study is especially considering the human driver's steering process; path planning, feed-forward steering, and preview feedback steering. Important human factors, such as the view angle and the neuromuscular system, are also regarded. The suggested driver model is simulated based on the CarSim vehicle model in a Simulink environment. The simulation results are then compared to the actual vehicle test data and to the driving simulator test data with regard to the four human driver levels. The driver model suggested in this study represents the human steering behaviour and well matches the real vehicle test data.

Ride comfort enhancement and energy efficiency using electric active stabiliser system

This paper introduces the concept of a road input control system to coexist superior ride comfort performance with driving stability using an electric active stabiliser system. The specific road input control system studied, extends the skyhook theory in the roll direction to offer both ride comfort and driving stability. The predictions of performance achieved by this method have been confirmed through actual vehicle tests to offer superior ride comfort and tracing performance. Moreover, consumed power of the road input control was 7–25% of conventional steering input control because of the efficiency of the regenerated power in the active stabiliser system.

Autonomous terrain-following for unmanned air vehicles

This paper presents an integrated guidance and control design scheme for an unmanned air vehicle (UAV), and its flight test results. The paper focuses on the longitudinal control and guidance aspects, with particular emphasis on the terrain-following problem. An introduction to the mission, and the terrain-following problem is given first. Waypoints for climb and descent are defined. Computation of the reference trajectory in the vertical plane is discussed, including a terrain-following (TF) algorithm for real-time calculation of climb/descent points and altitudes. The algorithm is particularly suited for online computation and is therefore useful for autonomous flight. The algorithm computes the height at which the vehicle should fly so that a specified clearance from the underlying terrain is always maintained, while ensuring that the vehicle’s rate of climb and rate of descent constraints are not violated. The output of the terrain-following algorithm is used to construct a smooth reference trajectory for the vehicle to track. The design of a robust controller for altitude tracking and stability augmentation of the vehicle is then presented. The controller uses elevators for pitch control in the inner loop, while the reference pitch commands are generated by the outer altitude control loop. The controller tracks the reference trajectory computed by the terrain-following algorithm. The design of an electromechanical actuator for actuating the control surfaces of the vehicle during flight is also discussed. The entire guidance and control scheme is implemented on an actual experimental vehicle and flight test results are presented and discussed.

EPSシステムの設計支援用簡易ステアリングシミュレータの開発(機械力学,計測,自動制御)

The estimation of steering characteristics such as steering feel by using only computer simulation technology is extremely difficult. To solve this problem, a steering simulator referred to as "Hard-in-the Loop" has been developed by researchers, in which the steering reaction force on the tie rod is produced by an AC servo motor and a ball screw, assuming mathematical models of the vehicle and tires are known. The purpose of this study is to develop a more simplified steering simulator, in which the electric motor in the EPS produces steering reaction torque and conventional assist torque. In this paper, emphasis is placed on the validity of this proposed means of generating steering reaction torque. The usefulness of this steering simulator was ascertained by comparing the test results of the simulator with the results obtained from computer simulation and actual vehicle testing.

Development of Fuel Cell Stack Durability based on Actual Vehicle Test Data: Current Status and Future Work

Development of Fuel Cell Stack Durability based on Actual Vehicle Test Data: Current Status and Future Work

Three-Way Catalyst Meeting Euro III Emission Standards for Motorcycles

The Pt/Pd/Rh three-way catalyst was prepared using a high-performance Ce0.55Zr0.35Y0.05La0.05O2 solid solution and high surface area La-stabilized alumina (La/Al2O3). The activity and durability of the catalysts under simulated conditions and actual vehicle test conditions were studied. The results revealed that Ce0.55Zr0.35Y0.05La0.05O2 solid solution maintains superior textual and oxygen storage properties, and La/Al2O3 has superior textual properties. The catalyst had high low-temperature activity, wide air-to-fuel ratio windows, and good thermal stability. The results from the emission test of a motorcycle showed that the catalyst can meet Euro III emission requirements.

Combined bounce, pitch, and roll dynamics of vehicles negotiating single speed bump events

This paper investigates vehicle dynamic response for the increasingly common manoeuvre over single speed bumps, which is a non-trivial complex motion. One major aim of the study is to investigate the effect of the anti-roll bar upon vehicle body dynamics, while negotiating such traffic calming features. Numerical predictions are made with an intermediate vehicle model, whose results conform well to the actual vehicle tests. These results seem to suggest that events caused by truncated speed bumps can have implications for design of anti-roll bars from a ride comfort viewpoint, over and above the usual requirements dictated by safe vehicle handling.

Suppression of brake squeal noise applying finite element brake and pad model enhanced by spectral-based assurance criteria

An enhanced dynamic finite element (FE) model with friction coupling is applied to analyze the design of disc brake pad structure for squeal noise reduction. The FE model is built-up from the individual brake component representations. Its interfacial structural connections and boundary conditions are determined by correlating to a set of measured frequency response functions using a spectral-based assurance criterion. The proposed friction coupling formulation produces an asymmetric system stiffness matrix that yields a set of complex conjugate eigenvalues. The analysis shows that eigenvalues possessing positive real parts tend to produce unstable modes with the propensity towards the generation of squeal noise. Using a proposed lumped parameter model and eigenvalue sensitivity study, beneficial pad design changes can be identified and implemented in the detailed FE model to determine the potential improvements in the dynamic stability of the system. Also, a selected set of parametric studies is performed to evaluate numerous design concepts using the proposed dynamic FE model. The best pad design attained, which produces the least amount of squeal response, is finally validated by comparison to a set of actual vehicle test results.

3108 ステアリングHILシミュレータの開発 : 第2報 ステアリング操舵性能の定量的評価(シミュレーション技術,OS3 交通・物流システムのダイナミクスと制御,一般講演)

Steering reaction torque is one of the important information for drivers since it has significant influence on the maneuverability of the vehicle. Even with today's advanced simulation technology, however, it is very difficult to simulate factors such as the accurate steering feeling. The ultimate purpose of this study is to evaluate steering feeling using developed steering Hardware-in-the-loop (HIL) simulator. In this report, the difference between the results of simulator testing and actual vehicle testing was investigated. And the complement element is installed into HIL simulator to evaluate steering feeling as actual vehicle testing.

Development of hardware-in-the-loop simulation system for testing multiple ABS and TCS modules

Vehicle tests for evaluating performance of vehicle control devices are often time consuming, expensive, and not reproducible. The hardware-in-the-loop simulation (HILS) is promising on this matter since it provides time- and cost-effective ways of vehicle testing with repeatability. In this research, a HILS system has been developed to test commercial ABS and TCS units. The system has been designed to accommodate multiple ABS/TCS modules simultaneously in order to facilitate performance comparison between different ABS/TCS modules. To enhance the validity of the HILS results, CarSim has been used to generate a reliable vehicle model. The cockpit of the HILS system has been designed to be similar to that of an actual vehicle to provide a realistic environment for the operator. The HILS system has been tested with two ABS modules and one TCS module. For the same test conditions, actual vehicle tests have been performed to validate reliability of the HILS system.

A study on the brake-by-wire system using hardware-in-the-loop simulation

HILS (Hardware-In-the-Loop Simulation) is a scheme that incorporates hardware components of primary concern in the numerical simulation environment. Due to its advantages over actual vehicle test and pure simulation, HILS is being widely accepted in automotive industries as a test bench for designing, evaluating, and benchmarking vehicle control units. Developed in this study is a HILS system for the EHB (Electro-Hydraulic Brake) brake-by-wire system. The system includes a high pressure generator and a valve control system that independently modulates the brake pressures at four wheels. An EHB control logic and a VDC (Vehicle Dynamics Control) logic were tested in the HILS system. Test results under various driving conditions are presented in this paper.

Lateral control of autonomous vehicle by yaw rate feedback

In an autonomous vehicle, the reference lane is continually detected by a machine vision system. Then the vehicle is steered to follow the reference yaw rates which are generated by the deviations of lateral distance and the yaw angle between the vehicle and the reference lane. To cope with the steering delay and the side-slip of a vehicle, a PI controller is introduced for the yaw rate feedback. It is tuned by the simulation that the vehicle is modeled as 2 DOF and 79 DOF and verified by the results of the actual vehicle test. The lateral control algorithm by the yaw rate feedback has good performance of lane tracking and passenger comfort.

Vehicle stability control strategy for steer by wire system

It has been confirmed through sudden-brake test on μ-split roads, etc. that great vehicle stability is achieved by automatic front-wheel steering control. Steer by wire prevents unnecessary forces from reaching the driver because it eliminates the direct mechanical linkage of a conventional steering column. By using D ∗ control, this system can offer high steering response and reduced driving effort, among other benefits. The effectiveness of the proposed control was investigated on a driving simulator and by actual vehicle testing, and we attempted to achieve control parameter optimization by investigating the relationship between control parameters and vehicle dynamics by computer simulation.

Throttle actuator control system for vehicle traction control

Accurate and quick positioning of the throttle valve in a gasoline engine is required to implement various systems such as traction control systems (TCS), cruise control systems and drive-by-wire systems. In this research, the throttle actuator system for TCS application was developed. Unlike other systems, this system consists of only one throttle body to obtain small volume and low manufacturing cost, and uses a DC servo motor for quick and accurate responses. In order to drive the DC motor, a PWM signal generator and PWM amplifier were built and interfaced to the motor and controller. This paper also presents the position control logic of the throttle actuator with the TDC (time delay control) scheme with a variable reference model. By varying the reference model based on the size of the step changes in the target throttle angle, the TDC scheme yields good transient response characteristics in that both overshoot prevention and a quick response time are achieved. Actual vehicle tests with this developed system incorporated with the TCS system show that it satisfies all the conditions required for the TCS operation.

Development of TCS slip control logic based on engine throttle control

Slip control systems are used to prevent wheel slipping and to improve acceleration performance, stability and steerability on slippery roads through the engine torque and/or brake torque control. This paper mainly deals with the engine control algorithm via adjustment of the engine throttle angle. The slip control algorithm developed in this research includes a control gain scheduling part and a road estimating part to enhance control performance. Various actual vehicle tests have been carried out on low friction roads in order to verify the developed slip control algorithm. The test results show that the controlled vehicle is superior to the non-controlled vehicle in acceleration performance and stability.

Computational Vibration Analysis of Vehicle Shimmy by a Power-Work Method

SUMMARY This paper presents the simulation of vehicle shimmy for a mid-size truck with focus on a computational analysis tool that measures the power and corresponding work in dissipating the excitation energy. After a review of shimmy theory the power and work equations and their response classification in vibrating systems are introduced. Next, model validation compares the full vehicle model to an actual test vehicle. Finally, two designs that suppress shimmy in the test vehicle are analyzed in the model by the power-work method, showing components that effectively dissipate the shimmy energy.

A Sliding Mode Controller for Wheel Slip Ratio Control System

SUMMARY A sliding mode controller has been developed for a wheel slip ratio control system for commercial vehicles with sluggish braking actuators to replace conventional if-then rule-like ABS control laws. New techniques overcome the tendency of sliding mode controllers to chatter. Computer simulation (hardware-in-the-loop simulation) and actual vehicle tests verified the effectiveness of this method to suppress chattering and keep the wheel slip ratio in a desirable range during braking on low-friction road surfaces.

室内摩耗試験におけるドラム曲率がタイヤの摩耗に及ぼす影響の理論的考察

Indoor test machines have been used for evaluating tire tread wear because of actual vehicle testing required much cost and time. The research paper was published and was described that the tread wear due to the drum was the same tread wear with the flat belt. Vehicles mainly travel on flat road surfaces. Therefore, a flat belt type machine should be used for investigating tire tread wear. Drum type machines, however, are used as economical testing machines.In this paper, we investigated analytically the influence of drum curvature on the tire tread wear by calculating the friction energy in the contact surface. The analytical results were compared with experimental results that had published. We obtained the relationship between the friction energy on the flat belt and on the drum. Analytical results was good agreement with experimental results.