Hiroshi Fujimoto

Bio: Hiroshi Fujimoto is an academic researcher from University of Tokyo. The author has contributed to research in topics: Feed forward & Electric vehicle. The author has an hindex of 39, co-authored 622 publications receiving 6406 citations. Previous affiliations of Hiroshi Fujimoto include Kyoto University & NSK Ltd..

Perfect tracking control based on multirate feedforward control with generalized sampling periods

Abstract: In this paper, a novel perfect tracking control method based on multirate feedforward control is proposed. The advantages of the proposed method are that: (1) the proposed multirate feedforward controller eliminates the notorious unstable zero problem in designing the discrete-time inverse system; (2) the states of the plant match the desired trajectories at every sampling point of reference input; and (3) the proposed controller is completely independent of the feedback characteristics. Thus, highly robust performance is assured by the robust feedback controller. Moreover, by generalizing the relationship between the sampling period of plant output and the control period of plant input, the proposed method can be applied to various systems with hardware restrictions of these periods, which leads to higher performance. Next, it is shown that the structure of the proposed perfect tracking controller is very simple and clear. Illustrative examples of position control using a DC servomotor are presented, and simulations and experiments demonstrate the advantages of this approach.

Lateral Stability Control of In-Wheel-Motor-Driven Electric Vehicles Based on Sideslip Angle Estimation Using Lateral Tire Force Sensors

Abstract: This paper presents a method for using lateral tire force sensors to estimate vehicle sideslip angle and to improve vehicle stability of in-wheel-motor-driven electric vehicles (IWM-EVs) Considering that the vehicle motion is governed by tire forces, lateral tire force measurements give practical benefits in estimation and motion control To estimate the vehicle sideslip angle, a state observer derived from the extended-Kalman-filtering (EKF) method is proposed and evaluated through field tests on an experimental IWM-EV Experimental results show the ability of a proposed observer to provide accurate estimation Moreover, using the estimated sideslip angle and tire cornering stiffness, the vehicle stability control system, making best use of the advantages of IMW-EVs with a steer-by-wire system, is proposed Computer simulation using Matlab/Simulink-Carsim and experiments are carried out to demonstrate the effectiveness of the proposed stability control system Practical application of lateral tire force sensors to vehicle control systems is discussed for future personal electric vehicles

Estimation of Sideslip and Roll Angles of Electric Vehicles Using Lateral Tire Force Sensors Through RLS and Kalman Filter Approaches

Abstract: Robust estimation of vehicle states (e.g., vehicle sideslip angle and roll angle) is essential for vehicle stability control applications such as yaw stability control and roll stability control. This paper proposes novel methods for estimating sideslip angle and roll angle using real-time lateral tire force measurements, obtained from the multisensing hub units, for practical applications to vehicle control systems of in-wheel-motor-driven electric vehicles. In vehicle sideslip estimation, a recursive least squares (RLS) algorithm with a forgetting factor is utilized based on a linear vehicle model and sensor measurements. In roll angle estimation, the Kalman filter is designed by integrating available sensor measurements and roll dynamics. The proposed estimation methods, RLS-based sideslip angle estimator, and the Kalman filter are evaluated through field tests on an experimental electric vehicle. The experimental results show that the proposed estimator can accurately estimate the vehicle sideslip angle and roll angle. It is experimentally confirmed that the estimation accuracy is improved by more than 50% comparing to conventional method's one (see rms error shown in Fig. 4). Moreover, the feasibility of practical applications of the lateral tire force sensors to vehicle state estimation is verified through various test results.

Molecular orbital calculations of the electronic structure of borazane

Abstract: An ab initio molecular orbital calculation of the addition compound of boron hydride and ammonia has been carried out. By expanding the molecular orbitals of the addition compound in terms of the molecular orbitals of boron hydride and of ammonia in a separated state, the origin of charge transfer and bond formation between these two species in the interaction has been studied. A configuration analysis of the wavefunction of the addition compound has been performed.

Development of Wireless In-Wheel Motor Using Magnetic Resonance Coupling

Abstract: In-wheel motors (IWMs) in electric vehicles are particularly important for motion control. A conventional IWM is powered from a battery aboard the vehicle via cables. Since power cables and signal cables of an IWM are exposed to harsh environments, they can possibly become disconnected by high acceleration or vibration. In order to overcome this problem, the wireless-in wheel motor (W-IWM) has been proposed. The risk of disconnection would disappear if the cables of the IWM are removed. One way to implement wireless power transfer is by utilizing the magnetic resonance coupling method. However, motion of the W-IWM, and thus, a misalignment between the wheel and the vehicle, leads to variations in the secondary-side voltage provided. To account for this, this paper discusses two new control methods. One proposed method maintains the secondary voltage using a hysteresis comparator. The other proposed method estimates the secondary inverter output power, applying it to a feedforward controller in order to keep the secondary dc-link voltage constant. Experimental results show that these methods can drive a W-IWM effectively with high efficiency.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Role of Frontier Orbitals in Chemical Reactions

Abstract: Since the 3rd century for more than a thousand years chemistry has been thought of as a complicated, hard-to-predict science. Efforts to improve even a part of its unpredictable character are said to have born fruit first of all in the success of the \" electronic theory \". This was founded mainly by organic chemists , such as Fry, Stieglitz, Lucas, Lapworth and Sidgwick, brought to a completed form by Robinson and Ingold, and developed later by many other chemists. 1 In the electronic theory, the mode of migration of electrons in molecules is noted and is considered under various judgements. For that purpose, a criterion is necessary with respect to the number of electrons which should originally exist in an atom or a bond in a molecule. Therefore, it can be said to be the concept by Lewis of the sharing of electrons that has given a firm basis to the electronic theory. 2 In the organic electronic theory, the chemical concepts such as acid and base, oxidation and reduction and so on, have been conveniently utilized from a long time ago. Furthermore, there are terms centring closer around the electron concept, such as electrophilicity and nucleophilicity, and electron donor and acceptor both being pairs of relative concepts. One may be aware that these concepts can be connected qualitatively to the scale of electron density or electric charge. In the electronic theory, the static and dynamic behaviours of molecules are explained by the electronic effects which are based on nothing but the distribution of electrons in a molecule. The mode of charge distribution in a molecule can be sketched to some extent by the use of the electronegativity concept of atoms through organic chemical experience. At the same time, it is given foundation, made quantitative , and supported by physical measurements of electron distribution and theoretical calculations based on quantum theory. The distribution of electrons or electric charge-with either use the result is unchanged-in a molecule is usually represented by the total numbers (generally not integer) of electrons in each atom and each bond, and it was a concept easily acceptable even to empirical chemists as having a tolerably realistic meaning. Therefore, chemists employed the electron density as a fundamental concept to explain or to comprehend various phenomena. In particular, for the purpose of promoting chemical investigations, researchers usually rely upon the analogy through experience, and the electron density …

Catalytic Carbophilic Activation: Catalysis by Platinum and Gold π Acids

Abstract: The ability of platinum and gold catalysts to effect powerful atom-economic transformations has led to a marked increase in their utilization. The quite remarkable correlation of their catalytic behavior with the available structural data, coordination chemistry, and organometallic reactivity patterns, including relativistic effects, allows the underlying principles of catalytic carbophilic activation by π acids to be formulated. The spectrum of reactivity extends beyond their utility as catalytic and benign alternatives to conventional stoichiometric π acids. The resulting reactivity profile allows this entire field of catalysis to be rationalized, and brings together the apparently disparate electrophilic metal carbene and nonclassical carbocation explanations. The advances in coupling, cycloisomerization, and structural reorganization—from the design of new transformations to the improvement to known reactions—are highlighted in this Review. The application of platinum- and gold-catalyzed transformations in natural product synthesis is also discussed.