Torque-based Optimal Acceleration Control for Electric Vehicle

The existing research of the acceleration control mainly focuses on an optimization of the velocity trajectory with respect to a criterion formulation that weights acceleration time and fuel consumption. The minimum-fuel acceleration problem in conventional vehicle has been solved by Pontryagin＇s maximum principle and dynamic programming algorithm, respectively. The acceleration control with minimum energy consumption for battery electric vehicle（EV） has not been reported. In this paper, the permanent magnet synchronous motor（PMSM） is controlled by the field oriented control（FOC） method and the electric drive system for the EV（including the PMSM, the inverter and the battery） is modeled to favor over a detailed consumption map. The analytical algorithm is proposed to analyze the optimal acceleration control and the optimal torque versus speed curve in the acceleration process is obtained. Considering the acceleration time, a penalty function is introduced to realize a fast vehicle speed tracking. The optimal acceleration control is also addressed with dynamic programming（DP）. This method can solve the optimal acceleration problem with precise time constraint, but it consumes a large amount of computation time. The EV used in simulation and experiment is a four-wheel hub motor drive electric vehicle. The simulation and experimental results show that the required battery energy has little difference between the acceleration control solved by analytical algorithm and that solved by DP, and is greatly reduced comparing with the constant pedal opening acceleration. The proposed analytical and DP algorithms can minimize the energy consumption in EV＇s acceleration process and the analytical algorithm is easy to be implemented in real-time control.

The Confirmation of Hypothesis of the Absolute Reference System

The purpose of the research in this article is the examination of the agreement of the hypothesis of the absolute reference system with the results of experiments that have been implemented in the past in order to confirm the special theory of relativity. To achieve this goal, we have chosen for discussing a theoretical topic of electromagnetism, that of electromagnetic mass calculation, and some experiments, some of which concern the transverse Doppler effect in a rotated system, two experiments that concern the kinetic energy measurement of accelerated electrons, one of which is the well known Bertozzis experiment, one experiment that concerns the propagation of Coulomb fields and one more experiment that concerns the effect of annihilation. The basic principles of the hypothesis of the absolute reference system, and the electromagnetic theory derived from these principles, are used to explain the experimental results. In these examples, the hypothesis of the absolute reference system is confirmed, since the experimental results agree with the predictions of this hypothesis. Also, in the discussion of calculation of electromagnetic mass is addressed the difficulty of solving this problem, when someone tries to solve this according to the energy-mass relation of the theory of relativity.

D'ALEMBERT PRINCIPLE IN THE VELOCITY SPACE

According to Newton's dynamical equation of the system of particles, the force is considered to be the function of the coordinate r, velocity and time t, and the various formulae for D'Alembert principle of the velocity space in both the holonomic and nonholonomic systems are deduced by introducing the concept of kinetic energy in the velocity space (i.e. the accelerated energy).

Experimental research on critical point hy- pothesis

According to the critical point hypothesis (CPH), energy release would accelerate in power law before occurrence of large earthquakes or failure of brittle materials. In the paper, CPH was studied by acoustic emission experiments of large-scale rock samples. Three kinds of rock samples were used in the experiments. The tri-axial loading con- dition was applied under different loading histories. The released elastic energy (Acoustic emission) was recorded with acoustic emission technique as microcracks emerged and developed inside the rock samples. The experimen- tal results gave a further verification on the CPH. The elastic energy release of rock samples would accelerate be- fore the failure even under different experimental conditions. Primary studies were also made on medium-term earthquake prediction by using accelerating energy release (AER) in the paper.

Study on medium-short term earthquake forecast in Yunnan Province by precursory events

The medium-short term forecast for a certain kinds of main earthquake events might be possible with the time-to-failure method presented by Varnes (1989), Bufe and Varnes (1993), which is to simulate an accelerative releasing model of precursory earthquake energy. By fitting the observed data with the theoretical formula, a medium-short term forecast technique for the main shock events could be established, by which the location, time and magnitude of the main shock could be determined. The data used in the paper are obtained from the earthquake catalogue recorded by Yunnan Regional Seismological Network with a time coverage of 1965~2002. The statistical analyses for the past 37 years show that the data of M2.5 earthquakes were fairly complete. In the present paper, 30 main shocks occurred in Yunnan region were simulated. For 25 of them, the forecasting time and magnitude from the simulation of precursory sequence are very close to the actual values with the precision of about 0.57 (magnitude unit). Suppose that the last event of the precursory sequence is known, then the time error for the forecasting main shock is about 0.64 year. For the other 5 main shocks, the simulation cannot be made due to the insufficient precursory events for the full determination of energy accelerating curve or disturbance to the energy-release curve. The results in the paper indicate that there is no obviously linear relation in the optimal searching radius for the main shock and the precursory events because Yunnan is an active region with damage earthquakes and moderate and small earthquakes. However, there is a strong correlation between the main shock moment and the coefficient k/m. The optimal fitting range for the forecasting time and magnitude can be further reduced using the relation between the main shock moment lgM0 and the coefficient lgk/m and the value range of the restricting index m, by which the forecast precision of the simulated main shock can be improved. The time-to-failure method is used to fit 30 main shocks in the paper and more than 80% of them have acquired better results, indicating that the method is prospective for its ability to forecast the known main shock sequence. Therefore, the prospect is cheerful to make medium-short term forecast for the forthcoming main shocks by the precursory events.

Gauss Principle of Least Compulsion for Relative Motion Dynamics and Differential Equations of Motion

This paper focuses on Gauss principle of least compulsion for relative motion dynamics and derives differential equations of motion from it. Firstly, starting from the dynamic equation of the relative motion of particles, we give the Gauss principle of relative motion dynamics. By constructing a compulsion function of relative motion, we prove that at any instant, its real motion minimizes the compulsion function under Gaussian variation, compared with the possible motions with the same configuration and velocity but different accelerations. Secondly, the formula of acceleration energy and the formula of compulsion function for relative motion are derived because the carried body is rigid and moving in a plane. Thirdly, the Gauss principle we obtained is expressed as Appell, Lagrange, and Nielsen forms in generalized coordinates. Utilizing Gauss principle, the dynamical equations of relative motion are established. Finally, two relative motion examples also verify the results' correctness.

Role of inter-particle collision on solids acceleration in riser

Collision among particles plays a significant role in governing the structure of gas-solids flow in a riser, especially in the dense and acceleration region. The inter-particle collision is the major cause not only for the kinetic energy dissipation （in terms of additional pressure drop beyond the solids hold-up） but also for the control of solids acceleration （in terms of a balancing force to prevent a free acceleration of solids）. A neglect of the balancing force of inter-particle collision against the hydrodynamic force in the solids momentum equation would simply overestimate the solids acceleration or concentration while underestimate the axial gradient of pressure along the riser by a large margin, typically by up to two orders of magnitude. This paper aims to illustrate the importance of the collision on the characteristic of the gas-solids riser flow. Our analysis shows that the collision force should be of the same order of magnitude as that of the drag force in the dense and acceleration region, which can be far beyond that of gravitational force on solids. A simple formulation of the collision force is therefore proposed to bear a similar format of drag force, with regard to the dependence upon local solids properties.With the inclusion of the proposed correlation of collision force in the solids momentum equation, our model would be able to yield reasonable phase distributions of gas-solid flows, which can be validated, in a bulk range, against available measurements of solids volume fraction and axial gradient of pressure.

Analysis of gamma-emitting radionuclides in soils around high energy accelerators

Objective To investigate the specific activities of gamma radionuclides in the soils around high energy accelerators,and to analyze the influence of rays emitted by nuclides with characteristic peaks at similar energy points on nuclide measurement results,in order to provide reference for the accurate identification of radionuclides.Methods GR5021 high-purity germanium gamma spectroscopy system was used to measure the specific activities of gamma-emitting radionuclides 226Ra,232Th,238U,40K and artificial radionuclides 54Mn,52Mn,7Be,22Na,59Fe,95Zr in six soil samples around three kinds of high energy accelerators,and the theoretical counts of the characteristic peak of 835.7keV were compared with the measured counts of the characteristic peak of 54Mn.Results The specific activity ranges of gamma-emitting radionuclides 226Ra,232Th,238U and 40K in the soils around three kinds of high energy accelerators were 55.5–171,34.9–99.9,21.9–79.3 and 247–680 Bq/kg,respectively.The specific activities of artificial radionuclides 52Mn,7Be,22Na,59Fe and 95Zr were basically lower than the minimum detection limit.A characteristic peak was found at the energy point of 835.7keV in six soil samples,and the corresponding total absorption peak counts were from 228Ac of 232Thdecay daughter.Conclusions The specific activities of gamma-emitting radionuclides were at the normal natural background levels.The specific activities of artificial radionuclides were basically lower than the minimum detection limits.For 232Th,when its specific activity is above 40 Bq/kg,characteristic peak of its decay daughter 228Ac could be misjudged as characteristic peak of 54Mn.

New scheme to trigger fusion in a compact magnetic fusion device by combining muon catalysis and alpha heating effects

The application of laser pulses with psec or shorter duration enables nonthermal efficient ultrahigh acceleration of plasma blocks with homogeneous high ion energies exceeding ion current densities of 10^(12) A cm^(-2). The effects of ultrahigh acceleration of plasma blocks with high energy proton beams are proposed for muon production in a compact magnetic fusion device. The proposed new scheme consists of an ignition fusion spark by muon catalyzed fusion(μCF) in a small mirror-like configuration where low temperature D–T plasma is trapped for a duration of 1 μs. This initial fusion spark produces sufficient alpha heating in order to initiate the fusion process in the main device. The use of a multi-fluid global particle and energy balance code allows us to follow the temporal evolution of the reaction rate of the fusion process in the device. Recent progress on the ICAN and IZEST projects for high efficient high power and high repetition rate laser systems allows development of the proposed device for clean energy production. With the proposed approaches,experiments on fusion nuclear reactions and μCF process can be performed in magnetized plasmas in existing kJ/PW laser facilities as the GEKKO-LFEX, the PETAL and the ORION or in the near future laser facilities as the ELI-NP Romanian pillar.