Hidehisa Yoshida

Lane change steering manoeuvre using model predictive control theory

This paper is a fundamental study on steering manoeuvre (driver model) when the steering angle input is obtained via Model Predictive Control (MPC). Conventional front steering angle for the lane change manoeuvre uses the sine wave input. This is very simple but this feed forward control input does not have adequate performance for mounting on real vehicle. For this reason, the steering input using MPC is developed. For example, the collision avoidance of lane-change steering manoeuvre has to deal with many constraints, so that the servo control like an LQI theory is not suitable for this problem. In addition, offline nonlinear programming calculation for optimal steering input of vehicle trajectory involves too heavy computational complexity to apply with real-time controllers. Desired control of the lane-change performance is conducted by the MPC approach with the constraint conditions. Potential advantage of the collision avoidance steering compared to the hard braking is estimated.

Target Following Brake Control for Collision Avoidance Assist of Active Interface Vehicle

In this study, target following brake control for collision avoidance assist by proposing active interface vehicle is developed. In this paper, the collision avoidance assist method for stopped vehicle in front, for recovering the recognition delay by inattentive driving is proposed. The system sets deceleration motion with the desired deceleration for the purpose of collision avoidance, etc. after the discovery in the driver in respect of the obstruction in front. In comparison with brake action of actual driver, the investigation which supplemented the shortage deceleration was carried out, to confirm the collision avoidance performance

Coupled Vibration of Passenger and Lightweight Car-Body in Consideration of Human-Body Biomechanics

Lightweight railway car body structure is a very important factor for the speeding up and energy saving of high-speed railway vehicles, such as magnetically levitated vehicles, and high-speed bullet train, Shinkansen. However, as lightening the car body decreases the bending rigidity of the car body, various elastic vibrations are liable to be induced in the car body, which results in deteriorating ride comfort for passengers. In this study, a special experimental set-up was made in order to investigate the coupled vibration of human body and flexible car body, the mass ratio of which is analogous to that of passengers and actual railway vehicles. After analyzing the behavior of human body affected by flexible car body vibration, computer simulation has been conducted by using a multi-degree-of-freedom flexible vehicle model of Shinkansen 700 series. The simulation analysis reveals that the resonant frequency of the first bending vibration mode depends on the passenger-seat dynamics, and the sensitiveness of the resonant peak is affected by the dynamic interaction, that is, coupled vibration between passengers and the car body.

Study on handling and stability using tire hardware-in-the-loop simulator

This paper presents development and application of a tire hardware-in-the-loop simulator (HILS) for evaluating vehicle dynamics. Tire HILS is a combination of a simulation (vehicle model) and an experiment (tires) part. The key to HILS is that simulation and experiment work is done together in the same time as a real time simulation. In this paper, analysis of handling and stabilities of a vehicle in plane motion is proposed. From the results, it can be stated that the response of the vehicle simulated on Tire HILS significantly gets closer to a real vehicle, as compared to simulation by off-line linear tire model.

Two-Dimensional Linear Friction Damper Consisting of Concave Cone and Cylindrical Member (Investigation of Performance by Numerical Simulation and Experiment)

A passive vibration isolation system consisting of a constant friction force has performance limitations; the isolation performance declines and the residual displacement becomes large in the case of the large friction force, while the resonant peak becomes large in the case of the small friction force. It is known that above drawbacks are avoidable when the friction force varies in proportion to the relative displacement. Recently, authors have proposed a simple linear friction damper mechanism that consists of a cylindrical block and a tilt lever supported with a pivot or a leaf spring. Performance of the vibration isolation system equipped with the proposed damper is investigated, and its effectiveness is confirmed by numerical simulations and the experiments. However, the motion of the mechanism is limited to one-dimension. This paper proposes an extended mechanism that can be applied to motion moving in two dimensions by combining the concave cone and the cylindrical member. The concave cone is supported with a universal joint on the apex side and its tilting motion is constrained by the restoring spring. The rounded edge of the cylindrical member is set up to contact the inside flank of the concave cone. When the cylindrical member moves in an arbitrary direction on the planar floor and pushes the concave cone, the normal and friction forces at the contact point vary depending on the displacement of the cylindrical member. The fundamental property and the performance of the proposed mechanism are investigated by numerical simulations and experiments.Copyright

Linear Friction Damper Consisted of Cylindrical Block and Inclined Lever (Improvement to Avoid Sprag-Slip Problem and Analytical Model to Verify Cause)

For the passive isolation systems, the ordinary friction damper of constant friction force has performance limitations. This is, because the isolation characteristic declines and the displacement remains apart from the equilibrium position after the disturbance disappears, when the friction force is large. It is known that the above drawbacks are improved when the friction force varies depending on the displacement. The authors have proposed a new type of friction damper in our previous paper. This friction damper uses an inclined lever, which contacts the cylindrical block by means of a rotational spring. The angle of inclination of the lever varies together with the displacement of the cylindrical block. Then, the normal and friction forces on the contact surface vary depending on the displacement. However, “Sprag-slip” vibration occurred in some cases in the experiments. This paper investigates the cause of the vibration and a design to prevent it. Then, an analytical model is proposed to simulate the problem and to estimate the effect of improvement.Copyright

Study on Car Body Tilting System Using Variable Link Mechanism (2nd Report, Tilting Control Design Based on the Strategy of Perfect Tilting Condition)

This paper aims to analyze fundamental dynamic characteristics of tilting railway vehicle using variable link mechanism for compensating both lateral acceleration that passengers feel and wheel load imbalance between inner and outer rails. Theoretical analysis is conducted to find “Perfect Tilting Condition” that is a geometric parameter set of link mechanism that can provide both zero lateral acceleration and zero wheel load imbalance simultaneously. This perfect tilting condition can be realized by changing the variable length of link mechanism so that this tilting control system is a kind of semi-active control. To change the length of link mechanism on curved section, feedforward + feedback optimal control theory is applied to the vehicle body tilting system with a developed variable link mechanism presented in 1st report. From computer simulation and experiment using a scale model, it is clarified that the proposed tilting control is effective to suppress both over-centrifugal acceleration and wheel load imbalance.

Study on Car Body Tilting System Using Variable Link Mechanism : 1st Report, Fundamental Characteristics of Pendulum Motion and Strategy of Perfect Tilting Condition

This paper aims to analyze fundamental dynamic characteristics of tilting railway vehicle using variable link mechanism for compensating both lateral acceleration that passengers feel and wheel load imbalance between inner and outer rails. In this report, geometric relations between the center of rotation, the center of gravity, and the positions of all four links of tilting system are analyzed. Then, equations of the pendulum motions of railway vehicle body with four-link mechanism are derived. This paper theoretically discusses about the geometrical shapes of link mechanism that can provide zero lateral acceleration and zero wheel load fluctuation simultaneously. Then, “perfect tilting condition”, which is the control target of feedforward tilting control, is derived by linear equation of tilting motion.

Investigation of Attitude Control Assistance System for Lane-Keeping Situation

Abstract Most of Lane-Keeping Assistance Systems are designed to regulate the lateral deviation of vehicle that may interfere the drivers maneuver in some cases resulting in deterioration of drivers workload. This paper proposes a new algorithm for the Lane-Keeping Assistant System by controlling of yaw angle of vehicle as called Attitude Control Assistance System or ACAS. The ACAS controls yaw angle of vehicle using two types of control inputs, steering torque and rear steering angle in this paper. The control system is designed and the systems effectiveness is evaluated based on experiment using driving simulator.