Kaneko Tetsuya

This study focuses on changes in the friction characteristics of paved roads under various conditions from the viewpoint of traffic safety. In general, the braking characteristics of road vehicles are examined using the μ–s characteristics of the tires. Therefore, in our research, we used three types of limited datasets and identified them using the Magic Formula proposed by Prof. Pacejka. Based on various experiments, it was shown that changes in the road surface environment, such as dry and wet conditions, significantly affect the μ–s characteristics, and this influence varies significantly depending on the pavement conditions. In this study, as the first stage of the analysis of these influences, it was clarified that the difference in the friction characteristics of wet and dry road surfaces varies significantly depending on the pavement surface, which is based on experimental results obtained using actual roads. As this variation is closely related to the safety of actual road traffic, we used a brush model, which is a dynamic model of the road surface and tires, to clarify the differences in this characteristic.

Using the road friction measurement method constructed in previous our studies, the measurement results of friction characteristics on dry and wet surfaces are shown. From this comparison, it is confirmed that the characteristics of the wet and dry roads studied so far can be expressed. Next, we study the velocity dependence of these properties. As a result, it is shown that the velocity dependence of μ-s characteristics on ordinary roads is almost non-existent. Finally, a method of expressing μ-s characteristics obtained by continuous friction measurement, which is a feature of this measurement system, is presented. And, it is shown the peak μ and lock μ obtained from these, and also shown the superiority of this measurement method.

The Personal Mobility Vehicle (PMV), which has an inward-tilting angle, turns with lateral force due to a large camber angle, so it is necessary to consider the lateral movement of the tire vertical load axis during turning. Although the steering torque mechanisms are very different from those of automobiles, there are not many studies of the steering torque mechanisms of PMVs. In this paper, based on the effects of the force of six components acting on the tires, a method for setting the steering axis specifications is derived, including the geometrical minimization of steering moment disturbance due to the vertical load reaction force during turning. Automobile tires have a significant ground camber angle when traveling on rutted roads, but they do not have it on slanted roads because the vehicle body tilts along the road surface. On the other hand, in PMVs, the vehicle body always keeps upright when traveling both on slanted roads and on rutted roads. Therefore, the tires have ground camber angles on both types of road surface. We study the straight running ability under such road surface disturbances based on the geometrical minimization of steering moment disturbance due to the vertical load reaction force during turning. This straight running ability can be a remarkable strong point of PMVs with an inward tilt mechanism. In this study, it was proved that the steering axis parameters can be derived uniquely by taking into consideration the requirement to zero the moment (disturbance) around the steering axis due to the reaction force against the vertical load at all internal tilt angles.

This study focuses on the possibility of constructing a database on friction coefficients for actual roads from the viewpoint of traffic safety. A measurement algorithm is established to construct a road friction-measuring device. Next, the tires are selected for use in the measurements and their characteristics are measured using a bench tire characteristic tester. The measuring device is designed and constructed based on these characteristics. Finally, using this device, the measurement results of the road friction characteristics for two types of road surfaces are presented.

In this study, dynamic maps are being constructed for the road stability of autonomous vehicles and vehicles equipped with ADAS (Advanced Driver-Assistance Systems), which are currently undergoing demonstration experiments. Tire and road surface friction characteristics, which govern vehicle motion performance, are important, and a database is being built to add road surface characteristics data, which vary in various driving environments, to the dynamic map. In previous research, a measurement method of road friction coefficient and an estimation method of road friction characteristics were proposed. However, there is a problem that the overall estimation accuracy is affected by the estimation accuracy of the coefficient of friction at the time of tire lock, and the estimation accuracy decreases. Therefore, in this paper, the friction coefficient, at the time of tire lock is estimated by the estimation method from the correlation between each coefficient of Magic Formula and the curvature of the friciton characteristic. This paper describes the results of an attempt to improve the estimation accuracy of overall road surface friction characteristics. In the future, we will ivestigate wheter the method studied can be used for other tires. Also, we will study vehicle dynamics control using the database constructed by using these method.

In a PMV that tilts inward on cornering, as with a motorcycle, the lateral force is mainly generated by the tire camber angle. Therefore, the steering angle required to drive on a trajectory is generally independent from the vehicle speed, as same as motorcycles. This PMV is steered by the steering wheel like a car, and there is a room to consider the matching between this steering interface and the steering characteristics. In this paper, the steering characteristics and the steering torque characteristics are compared with automobiles and motorcycles, and preliminarily consider the way to warn the cornering limit to drivers. In PMVs that do not show understeer characteristics or saturation of steering torque like cars and are not suitable for touchdown of the vehicle body like motorcycles, it seems necessary to warn the limit with additional torque to the steering wheel.

This research deals with the possibility for construction of the database on the braking friction coefficient for actual roads from the viewpoint of traffic safety especially for automated driving such as level 4 or higher. In an automated driving such levels, the controller needs to control the vehicle, but the road surface condition, especially the road friction coefficient on wet roads, snowy or icy roads, changes greatly, and in some cases, changes by almost one order. Therefore, it is necessary for the controller to constantly collect environment information such as the road friction coefficients and prepare for emergencies such as obstacle avoidance.However, at present, the measurement of the road friction coefficients is not systemically performed, and a method for accurately measuring has not been established. In order to improve this situation, this study examines a method for continuously measurement for the road friction characteristics such as μ-s characteristics.

抄録 操舵角に応じて内傾角を与えるパーソナルモビリティビークルにて，操舵トルクの復元側への補正手段が提案されているが，そのヒステリシスの与え方は明確になっていない．本報では，車両の内傾挙動によるヒステリシス発生メカニズムを分析し，その内傾角に比例した補正トルク付加による，ヒステリシスの解消方法を示した．

Personal Mobility Vehicle (PMV) which has an inward tilting angle according to the steering angle, turns with the lateral force due to large camber angle, so it is necessary to consider the lateral movement of the tire vertical load axis during turning. Although the steering torque mechanism are very different from those of automobiles, there are not many examples which studied the steering torque mechanism of PMV. In this study, based on the effects of six components force acting on the tires, a method for setting the steering axis specifications is derived, including the geometrical minimization of steering moment disturbance due to the vertical load reaction force during turning.

操舵角に応じて内傾角を与えるPMVは主にキャンバ角による横力で旋回するため，操舵トルク特性は巻き込み側となり自動車のそれとは大きく異なる．PMVの操舵トルク特性を整理し，低μ路やカウンタステア時の挙動も考察した上で，キャスタトレールと共に仮想横加速度に比例した復元トルクを付加する是正方法を提案する．

This paper describes the development and verification of target trajectory and speed control target calculation. The control target calculation system of the autonomous vehicle algorithm, which is the focus of this study, mimics an expert driver's direction and speed control in detail. The proposed algorithm consists of a driver model, which considers the risk potential, and vehicle dynamics model like a human driver. We think that a human driver drives under the influence of some obstacles and the oncoming vehicle on the road. And they change a driving action so that their risk is always kept low. At first we measured the traveling path and vehicle speed as a driving action of the human driver by the experiment in the real traffic condition. Next, we reproduced the driving action of the human driver by the proposed algorithm. The parameter of the risk potential driver model was estimated by the experiment results. In addition, we performed inspection by the simulation about calculated control target. As a result, it was confirmed that direction control and the vehicle speed control by proposed algorithm simulated the driving of the human driver in detail.

In this study, PMVs with an active inward tilting mechanism with three wheels, double front wheels and single rear wheel, were studied regarding front inner wheel lifting phenomena, capability of obstacle avoidance and energy balance of active tilting mechanism. Based on a comprehensive study of inner wheel lifting and obstacle avoidance, PMVs with a front wheel steering system as the most realistic specification were compared on capability of obstacle avoidance with passenger cars and motorcycles with those that have current market experience, and showed better capability. Although the energy consumption of an active inward tilting mechanism might be in conflict with the energy efficiency of small PMV concepts, the energy needed to tilt PMVs was very little compared with the general energy consumption of driving. It was clarified that the new PMV concepts with inward tilting mechanism have sufficient social acceptability from both mandatory points of safety and efficiency.

In this study, we investigate an adaptability of drivers to a personal mobility vehicle (PMV) us- ing leaning process. In this paper, control behavior of the drivers were analyzed by running ex- periment using the driving simulator(DS). First, The equivalent preview time was calculated from the data obtained in the DS experiment. As a result, it is found that there are “driving be- havior in which the main control algorithm with a positive equivalent preview time is feedfor- ward control” and “driving behavior in which the main control algorithm with a negative equiv- alent preview time is feedback control”. In addition, it was shown that the equivalent preview time used to calculate feedforward steering can be grasped by a check sheet on driver's work- load sensitivity. Next, the feedforward steering angle of the driver whose equivalent preview time is positive was calculated. As a result, the steering angle of the selected driver can be al- most reproduced by feedforward steering. In addition, it is shown that steering gain, constitute steering of the feedforward, is depending on the vehicle characteristics, and also the preview time is depending on each driver.

Traffic congestions and lack of parking spaces in urban areas, etc. may impair original benefits of cars, and now new ultra-small mobility concepts called Personal Mobility Vehicles (PMVs) are payed attention. Among them, PMVs with inward tilting mechanism in order to avoid over- turning on turning as same as motorcycles look realistic in innovative new traffic systems. In this report, PMVs with active inward tilting mechanism with three wheels; double front wheels + single rear wheel and front steering + rear traction, are studied on front inner wheel lifting phenomena, on capability of obstacle avoidance and on energy balance of active tilting mecha- nism. Then, sufficient social acceptability of inward tilting type PMVs was shown.

This paper considers personal mobility vehicles with lean mechanism. We performed an analysis of the influence of some sudden steering input on the tire contact performance with the roll motion by simulation analysis using multi-degree-of-freedom vehicle dynamics model for three type model (3 wheels and Rear Steering, 3 wheels and Front Steering, 4 Wheels and Front Steering). The results of the analysis showed the relationship between the dynamic response of roll motion with lean mechanism and two control method of the lean mechanism. Then We have proposed performance improvement methods by applying the closed loop lean control model and applying the unstable zero transfer function to the front wheel steering.

パーソナルモビリティビークル(PMV)の旋回時内傾の実現手段として,操舵角に応じた強制ストロークをサスペンションに与える例があるが,先行研究にて急操舵時の内輪浮きが指摘された.本報ではPMVのロール・ヨー特性の検討により,今後のPMV企画のために実用範囲で内輪浮きを起こさない車両諸元範囲(ロール・ヨー慣性,操舵角比など)を導出した. 原口哲之理, 景山一郎, 金子哲也 担当：研究計画，理論解析

This paper considers personal mobility vehicles with lean mechanism. We performed a sensitivity analysis of the influence of change in vehicle parameters, such as height of center of gravity and steer characteristics, on the rollover limit. To achieve this, a simulation analysis using a multi-degree-of-freedom vehicle dynamics model was performed. The results of the simulation analysis showed the relationship between the dynamic response of roll motion with lean mechanism from a maneuvering input and the rollover limit characteristic, including a phase delay.

The concept studies by driver's sense are absolutely necessary at early stage of development of Personal Mobility Vehicles (PMV), which have totally different mechanism from current cars. The purpose of this work is to make clear the requirements to Driving Simulators (DS) in order to study tilting type PMV. Then we prospect future PMV study by immersive DS with stereoscopic vision of five large screens.

エネルギー産業技術総合開発機構主導の「エネルギーITS推進事業」と題して2008年度から５ヵ年計画で実施された大型自動車の自動運転・隊列走行に関する研究開発プロジェクトを経て，自動運転車両の障害物回避，車線変更，合流時の自動操縦において人間が感受するリスク感覚を考慮したドライバモデルを制御目標生成アルゴリズムに適用した技術を確立してきた． 本稿では，上記の自律走行車両の運動制御において最も重要となるドライバの運転動作を考慮した制御目標生成アルゴリズムについてその理論の概要とこれまでの適用例を紹介する．

自律走行車両のステアリング制御に着目し，制御目標となる目標走行軌跡や車両状態量の生成について，レーンチェンジや障害物回避時の人間の運転動作を基本とした危険感ポテンシャルドライバモデルと車両運動性能を考慮した車両モデルを用いた制御目標生成アルゴリズムの提案を行った．また提案したアルゴリズムの妥当性検証の１つとして，熟練ドライバによる実車走行実験データと同様の走行環境から生成された制御目標との比較検証を行い，提案したモデルによって人間の運転行動の再現性を確認した．更に提案されたアルゴリズムにより生成された制御目標を用いた操舵制御による車両の誘導制御の実現性の確認をするため，多自由度の運動力学シミュレーションを行った結果について述べた．

（独）新エネルギー・産業技術総合開発機構は「エネルギーITS 推進事業」自動運転・隊列走行システムの研究開発に取組んでいる．本研究はこのシステムを構成する大型3軸トラックの横運動を表現する車両モデルに関するものである．その3 軸トラックは操舵機構を備えた前1 軸と操舵機構を備えない後2 軸で構成される．実路にはカントがあり曲線があり，車線維持のためあて舵が必要になる．曲線ではカント横力と旋回横力のつり合いから，カントを上り或いは下る．それを把握してモデルにして実路データと照合する．実用場面で想定される事象を表現して,それに対処する制御則検討の役にたつ自由度を備えたモデルから,制御のための簡単モデルへの展開の筋道としてのモデルの簡単化について示す．

This paper describes the development of a vehicle model for a steering control system on the platooning system of a heavy truck. In the vehicle model, the sideslip characteristic and steering characteristic were obtained from the measurement data by a steady-state turning test performed using an experimental vehicles for obtaining the equivalent cornering stiffness. The vehicle model corresponded to the measurement data of the experimental vehicle. Therefore, it was confirmed that the vehicle model had a high performance in the identification accuracy.

This paper proposes a steering control strategy for new transport system equipped with an all-wheel steering system to achieve zero off-tracking running. In this system, the center of each axle passes through the same locus, which is similar to the operation of trains. The control system is composed of two parts-the feedforward and feedback controllers. A sliding mode controller as a nonlinear robust control is applied and imparts sufficient robustness by correcting the steeringangle. This control system was validated by means of numerical simulations using a multi degree of freedom vehicle dynamics model.

This paper is concerned with the constructing of driver-vehicle-environment model for analyzed interaction between drivers and vehicles. We obtained different result of the fuel consumptions between two professional test drivers on mode-test in previous works. Therefore, it should be concerned with that not only the vehicle characteristics but also the interactions between drivers and vehicles on the assessment of fuel consumption. So we focused on the interactions from the viewpoint of driver-vehicle-environment model, especially, the longitudinal control interaction of drivervehicle-environment on heavy-duty vehicles. First, the driver's operations are enumerated by using of analysis of the experimental result. Next, the information which is perceived by the drivers is considered on each operation. After that, driver's operations are modeled by the multiple regression analysis using experimental result. Finally, the confirmation of the model is performed by the closedloop-simulation which is composed driver-vehicle-environment model and the vehicle model. As a result, the difference between simulation result of constructed model and experimental result is compared, and then the validity of the constructed mode is clearly.

３次元画像解析法を用い、運転者の状態推定手法の一つのツールとして、「顔面の表情」に着目した．まず、アンケートにより、基本6表情の客観評価を行った．そしてドライビングシミュレータの走行実験を用いて、顔面各部の表情変化を定量的に分析し、感情と運転負担との関係を調べた．また同時に運転者の生体負担を生理的反応から分析し、顔面表情との関係について検討を行った．

This article is concerned with the behavior of drivers of heavy-duty vehicles in following the preceding cars. It has been analyzed using a driver model. We first focus on a way for drivers to obtain information so that they can longitudinally control their vehicles. The model is used to describe the two kinds of control methods for drivers: the first is feed-forward, and the second is feed-back. Using multiple regression analysis, the feed-forward model was constructed taking the time-delay and the cut-off frequency of information into consideration. A feed-back model for information that cannot be described by feed-forward control was also constructed. Using a combination of the feed-forward and the feed-back model, a fore-and-aft control model was constructed, and we found that the driver model could provide a good description of the actual driver behavior. Finally, major factors involved in getting control information to the driver are clarified using factor analysis.

This paper is concerned with a driver's behavior of heavy-duty vehicle on car following condition using the driver model. Firstly, we focus on the way for drivers to get some information. The model describes for two control parts of drivers, one is the feed-forward control, and the other is feed-back control. The feed-forward model by using of multiple regression analysis was constructed in consideration of time delay and cut-off frequency of information. Furthermore, the feedback model of the part which cannot be described by the feedforward control is constructed. The fore and aft control model is constructed using combination between feed forward model and feedback model. Finally, it is shown that the driver model constructed in this research expressed actual driver behavior well.

4輪操舵機構を有する連節バスを対象とし、前輪車軸中心の通過位置を後輪車軸中心が同軌跡をたどる同轍走行の可能性とその際の制御手法について検討を行った。同轍制御の検討として制御システムを構築し、シミュレーションによる検討および、模型車両実験により制御則の妥当性を確認した。

This paper describes the stability of a tractor-semitrailer combination while braking. We first constructed nonlinear equations of motion for articulated vehicles with 8 degrees of freedom. Secondly, a simulation study was carried out to model vehicle performance in realistic situations. Jackknifing was recreated by simulation under conditions of traveling down a longitudinal road gradient. A study of the load rate of each tire showed that our model accurately describes the mechanism of jackknifing as well as the motion of limit performance conditions. Finally, the relationship between articulated vehicle, road gradient and limit performance is shown. (C) 2003 Society of Automotive Engineers of Japan, Inc. and Elsevier Science B.V. All rights reserved.

This paper is concerned with a driver model of heavy-duty vehicles for longitudinal control using the multiple regression analysis. Firstly, as a longitudinal control, modeling of a fore-and-aft operation was constructed for each gear based on experiment data for heavy-duty vehicles. Next, the gear change model was constructed to select a longitudinal control model. Using the factor analysis for the model, the relationship between input and output was analyzed. Finally, the driver's control for longitudinal direction was described using this driver model.

This paper is concerned with the running stability of tractor-semitrailer combination at braking. Firstly, we construct nonlinear equations of motion for the articulated vehicles, which have 9 degrees of freedom. Secondly, simulation study is carried out to show the vehicle performance in realistic situation. Jack-knifing on the straight road section was recreated by the simulation in consideration of road gradient not only for longitudinal direction but also for lateral direction. By using the concept of load rate of each tire, we confirmed that the model shows the mechanism of the jack-knifing on straight road section, and the motion of limit performance conditions. Finally, the relationship between limit performance, road gradient condition, and vehicle parameters is shown. These results emphasize the importance of observation of the tire load rate. Especially, rear axle of tractor should be considered when we discuss the limit performance of jack-knifing.

This paper is concerned with the running stability of tractor-semitrailer combination at braking. Firstly, we construct nonlinear equations of motion for the articulated vehicles, which have 9 degrees of freedom. Secondly, simulation study is carried out to show the vehicle performance in realistic situation. Jack-knifing on the straight road section was recreated by the simulation in consideration of road gradient not only longitudinal direction but also lateral direction . By using the concept of load rate of each tire, we confirmed that the model shows the mechanism of the jack-knifing on straight road section, and the motion of limit performance conditions. Finally, the relationship between limit performance, road gradient condition, and vehicle parameters is shown. These results emphasize the importance of observation of the tire load rate. Especially, rear axle of tractor should be considered when we discuss the limit performance of jack-knifing.

This paper describes a computer simulation study on performance of lateral guidance system for Dual Mode Truck. A stability limit of vehicle lateral motion is analyzed by using 9 DOF vehicle dynamic model. Relations between steering parameters and stability limit are shown. Experiments with actual Dual Mode Truck is carried out to show the effectiveness of the simulation study. Both the simulation study and experiment show that lateral guidance with one side guide rail causes unstable vehicle motion. It is shown that the unstable motion can be suppressed by cutting off the power steering equipment in the guideway.

機械式案内方式を搭載したデュアルモード車両のパワーステアリングを含めたステアリング系と機械式案内方式の連成問題の検討と安定化手法の提案，および都市間交通における走行速度の高速化手法の提案を行った．