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2013 Vol. 39, No. 1

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INS error modification method based on pseudo line-of-sights intersection for cruise missile
Zhang Youan, Kou Kunhu, Liu Aili, Geng Baoliang
2013, (1): 1-5.
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In absence of other navigation systems, cruise missile inertial navigation system (INS) error cumulates continuously with time. To solve this problem, a novel INS error modification method was proposed based on continuous observation to single known feature target without the need of distance information. According to the relative relation between cruise missile and feature target, the INS error modification problem was transferred into the problem of multiple pseudo feature targets locating cruise missile cooperatively by using the pseudo line-of-sights intersection method. Then the cruise missile biased position was estimated by the least squares algorithm. Treating the biased position and atmosphere system information as the observation, unbiased estimation of cruise missile position and velocity were realized with application of Kalman filter which can simultaneously estimate state and system error with direct feedthrough. Simulation results show that this method can modify INS position error and velocity error effectively.
Optical properties of sun synchronous orbit satellite
Shen Wentao, Zhu Dingqiang, Shi Liangchen, Cai Guobiao
2013, (1): 6-10.
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Optical characteristics of sun synchronous orbit satellite FY-1 were studied by simulation and experimental verification in visible and infrared band. Taken as input in calculation of infrared emission, temperature field on satellite surfaces were solved according to the radiation flux of outer sources. Undulating algorithm was used to describe appearance of the surface material. Reflection from satellite was based on judgments of shadow and bi-directional reflectance distribution function (BRDF) of surface materials. The signatures of FY-1 satellite were calculated and analyzed in infrared and visible band. The results show that infrared luminance of satellite surface is related with temperature. The maximum value is 90 W/(m2·sr) in 8~14 μm band, and 20 W/(m2·sr) in 14~16 μm band. The reflected light intensity show remarkable specula reflect. Maximum value is 2 200 W/sr. The measurement relative error is less than 20%.
Nonlinear finite element modeling and simulation for landing leg of lunar lander
Liang Dongping, Chai Hongyou, Zeng Fuming
2013, (1): 11-15.
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In order to accurately predict the load attenuation and energy absorption capabilities of landing leg during the landing event for supporting the design and optimization of landing gear mechanism, a new approach of using nonlinear finite element method in landing impact dynamic analysis was proposed. A detailed finite element model of landing leg was constructed and ABAQUS/Explicit was selected as the solver. Mass scaling technique was used to increase computational efficiency. Landing dynamic simulation of two landing scenarios were carried out, and the validity of analysis results were verified by comparison with test data. Results indicate that nonlinear finite element model with varied nonlinear factors can predict the landing performance of landing leg precisely. The flexibility of landing leg has a great effect on the friction between the inner and outer cylinders of leg struts, and the friction force can be decreased by increasing the leg stiffness.
Sampled-data control for a class of nonlinear time-delay systems
Fan Liying, Wu Junfeng
2013, (1): 16-21.
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The problem of sampled-data control was investigated for a class of nonlinear time-delay perturbed systems, where the upper bound of sampling intervals was known and both constant sampling and variable sampling were considered. The objective is to design a state-feedback sampled-data controller, which guarantees the closed-loop system exponentially stable and satisfies given performance index. By applying an input delay approach, the sampled-data control system was transformed into a continuous time-delay system. The novel time-dependent Lyapunov functions were introduced, which did not grow before the arrival of the next sampling time. By linear matrix inequality(LMI) approach, sufficient conditions were obtained, under which the nonlinear time-delay perturbed systems were exponentially stable. And simulation results show that the proposed method can improve the immunity of system.
Rectifying drifts of symplectic algorithm
Liu Xiaomei, Zhou Gang, Wang Yonghong, Sun Weirong
2013, (1): 22-26.
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Symplectic algorithm preserves the symplectic structure and laws for Hamiltonian systems compared with Runge-Kutta(RK) methods, but the point-wise numerical precision is worse for elliptic Hamiltonian systems. In order to improve it, the average statistic drift formulae of the third-order symplectic method and the fourth-order scheme were deduced. The precision was improved through compensating the drifts and step segmentation. A standard was built to find a better symplectic scheme in phase drift. The results of examples show that the third-order fractional step and symmetric symplectic algorithm(FSJS3 algorithm) is higher than the fourth-order one in phase accuracy, which is recommended for engineering application.
Effect of pre-corrosion on the MSD occurrence probability
Zhang Jianyu, Yuan Jun, Shi Xinhong
2013, (1): 27-30,41.
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Aimed at the multiple side damage(MSD) existed in the typical aircraft structural components,the occurrence probability of multiple side damage was investigated. The condition of pre-corrosion was dipping in 3.5% NaCl solution for 240 hours. The influence coefficient C was obtained based on the pre-corrosion and the normal fatigue experiment of 7B04-T74 aluminum alloy single detail specimens. The relationship could be estalished between the MSD occurrence probability under the specified pre-corrosion and the MSD occurrence probability under the normal fatigue condition. The formula of MSD occurrence probability after per-corrosion was gained. The calculation and experimentation results were compared. Results show that the new formula can compute the MSD occurrence probability after pre-corrosion commendably.
Nozzle chemical non-equilibrium effects based on strut combustor
Cheng Cheng, Qin Lizi, Liu Yu
2013, (1): 31-36.
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The finite volume method in implicit scheme and surrogate fuel C12H23's 10 species and 13 step reactions Arrhenius finite-rate model were adopted to investigate the non-equilibrium chemical reaction flow in kerosene-fueled scramjet single expansion ramp nozzle (SERN), and the ‘inlet thin layer' problem in SERN model was effectually solved by establishing the strut combustor-SERN model. Numerical simulation results show that the chemical non-equilibrium effect exits in the whole SERN, especially near the nozzle inlet zone; The SERN performance with non-equilibrium chemical reaction flow is obviously higher than that with frozen flow. With the increase of engine equivalent mixture ratio (ε) the δ grows up, which is the percentage of increment about nozzle thrust coefficient and lift coefficient with non-equilibrium chemical reaction flow relative to frozen flow.When the ε=0.8, thrust coefficient increment δCF=9.41%, lift coefficient increment δCY=16.39%, thus the chemical non-equilibrium effect of kerosene-fueled scramjet nozzle cannot be ignored.
Comparison of flow rate calculation method for ultrasonic flow measurement
Yu Yang, Zong Guanghua, Ding Fenglin
2013, (1): 37-41.
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Ultrasonic flow meter (UFM) calculates the flow rate, by measuring the difference of ultrasound transit time between the upstream direction and downstream direction. For the purpose of accurate flow measurement, transit time difference method and frequency difference method were compared from three aspects: change of environment temperature, accuracy of time measurement, and uncertainty calculation. Ultrasonic flow measurement experiment shows, when the flow meter is not calibrated, compared with frequency difference method, transit time difference method can achieve better accuracy. The calibrated factor for the transit time difference method is more linear, so better accuracy is achieved for full flow range measurement.
Degradation prediction based on correlation analysis and assembled neural network
Dang Xiangjun, Jiang Tongmin
2013, (1): 42-46,51.
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Efficient prognosis for remaining useful life of product is critical for both accelerated degradation testing and prognostics and health management, which are two hot points in recent years. A novel degradation prediction model was proposed to improve the long prediction capability for complex degradation path. Durbin-Watson method and partial correlation graph were utilized to analyze the decomposition results of wavelet transformation. Then, according to the characters of series, back propagation(BP) and wavelet neural network were assembled to predict degradation path. To verify the proposed method, wavelet neural network was selected as comparison. A practical degradation result demonstrates that this model can offer smaller mean square error (MSE) and higher prediction accuracy for remaining useful life (RUL).
System level link budget method
Liu Yan, Su Donglin, Zhang Kai, Li Yaoyao
2013, (1): 47-51.
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A simple mathematics iteration method was used to calculation of communication link margin between the ground station and aircraft in the past. However, factors such as complex vehicle model and climate conditions can cause radiation pattern distortion in the actual application. A method to assess the system level link budget was constructed. The relative changes equation of antenna radiation pattern caused by attitude change was established by applying rotation transformation matrix. Radiation pattern distortion information of installed antenna was simulated. Radiation pattern was used to data mining according to the relative changes variation. The link margin was computed under variable attitude by applying entire system link margin expression. Finally, examples about communication link performance between the ground navigation station and aircraft ultra-shortwave antenna, and between the ground heading station and aircraft heading antenna were used to validation the practicality of this method.
High-precision control for inertia momentum wheel based disturbance observer
Zhang Cong, Liu Gang, Li Guangjun
2013, (1): 52-56.
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To improve the output torque accuracy, a novel disturbance rejection strategy was presented with disturbance observer, based on the internal disturbance torque of inertia momentum wheel. By establishing the dynamic model of inertia momentum wheel, the existing torque control system was analyzed. The analysis results indicated that the torque control couldn't track the torque instruction without deflection, essentially. The proposed disturbance observer was designed. According to the estimated disturbance torque, the compensation control voltage was calculated. Ultimately, the control system was designed to carry out experimentations on the prototype of inertia momentum wheel. Experimental results demonstrate that the output torque accuracy can be improved from 0.01 N穖 to 0.002 N穖 by the disturbance rejection strategy. And the rotational speed and torque response curves are more smooth.
Development of Chang’E-1 operational simulator
Zheng Aiwu, Zhou Jianping, Ma Yongping
2013, (1): 57-61.
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Operational simulator is a satellite simulation system used to validate the flight program and ground control schemes, to train mission operators, constructing a realistic mission environment for system testing in the flight control center. The functional design, structure and using mode of Chang'E-1 operational simulator were introduced. In order to make the simulator jump to any orbit phase of the mission, and to improve the flexibility of system drilling, a new time jump method with orbit elements was presented. The simulator constructed a high-precision orbit dynamics model based on patched two-body with perturbation. In addition, part of onboard software was directly embedded into the simulator for the first time. Thus, the fidelity of the simulator was greatly improved. Centralized monitoring software was specifically designed for the simulator. The graphical man-machine interface facilitated the user's operation and management. The simulator was dependently used in the preparation of Chang'E-1 mission, and contributed for the success of it. Based on the development experience of the simulator, some advice is suggested for future simulator development.
Fault diagnosis of EHA-VPVM based on improved HHT
Liu Jun, Wang Zhanlin, Fu Yongling, Han Xu
2013, (1): 62-66.
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The system composition of the electro-hydrostatic actuator with variable pump displacement and variable motor speed(EHA-VPVM) was introduced. According to early fault signal features of EHA-VPVM, a new time-frequency analysis method Hilbert-Huang transform(HHT) was used. Two improved methods were introduced to solve problems of HHT, these problems were mode confusion and false intrinsic mode functions(IMF). The ensemble empirical mode decomposition(EEMD) was used to solve the mode confusion, and the correlation coefficient method was used to identify the effective IMF. In the early fault diagnosis experiment of EHA-VPVM prototype, Hilbert marginal spectrum and HHT spectrum were used to analyze the vibration signals of the permanent magnet brushless DC motor in different work conditions. The experiment results show the improved HHT well solved the problems of mode confusion and false IMF, and extracted the early fault features of the rolling bearing accurately. Moreover, the improved HHT method has good effect on the early fault diagnosis of EHA-VPVM.
Image scrambling algorithm based on chaotic weighted sampling theory and sorting transformation
Cao Guanghui, Hu Kai
2013, (1): 67-72.
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In order to enhance the security of digital image transmitted by network, Ye's algorithm, a typical image permutation algorithm based on sorting transformation was studied. Chaotic interval sampling sequence was introduced into image permutation algorithm. By doing so, image permutation effect was improved. In order to understand the internal principle of enhancing permutation effect, approximate entropy theory was employed. For enlarging key space, based on chaotic interval sampling and sorting transformation, new image permutation algorithm was designed in which Shannon's weighted sum idea was employed. In key space, permutation strength and security against reconstruction attack, the proposed permutation algorithm outperforms traditional chaotic sorting permutation algorithm.
Quality evaluation method for aircraft large components joining based on position and orientation measurement uncertainty
Du Fuzhou, Wu Pu
2013, (1): 73-77.
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In order to support the development and application of digital measurement assisted joining of large size aircraft components based on position and orientation, related work focus on measurement uncertainty of position and orientation, and quality evaluation methodology based on uncertainty was done. First of all, the mathematical expression and connotation of position and orientation in digital joining environment was proposed. Then an analytical algorithm based on covariance matrix for calculating the measurement uncertainty of position and orientation was proposed, and compared with the Monte Carlo simulation algorithm to verify its validity. The concept of digital measurement process capability index was given to evaluate the credibility of measurement result. Through implementing the mapping from measurement uncertainty of position and orientation to quality requirements, a novel methodology for evaluating the quality of large size components joining based on measurement uncertainty of position and orientation was proposed. Finally, the case of wing-fuselage digital joining was studied to present the verification of the feasibility and validity of the methodology.
Improvement of finite difference time domain method and its application to calculation of ultrasonic sound fields
Xu Na, Li Yang, Zhou Zhenggan, Yu Guang
2013, (1): 78-82.
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Finite difference time domain (FDTD) method is an effective way to establish ultrasonic testing model. However, a big difference between acoustic impedances of two adjacent materials may cause instability of the difference computation in the interface of two materials. To solve this problem, based on the conventional FDTD algorithm, an improved FDTD method was introduced by taking the average of the ultrasonic parameters of two materials on both sides of the interface. The model was built for the sound field calculation of the media consisted by two adjacent materials, one of which the acoustical impedance is five orders larger than the other, and the conventional and improved FDTD method were used respectively. Numerical calculation and practical experiments for an ultrasonic probe were accomplished. The results show that the improved FDTD method is a feasible and effective method for ultrasonic sound filed calculation.
Differential barometric altimetry method based on mobile phone base stations
Du Xiaohui, Pei Jun, Zhang Lirong, Liu Cheng
2013, (1): 83-88.
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A differential barometric altimetry was proposed for differential measurement to solve poor elevation positioning accuracy in existing satellite navigation and positioning systems by using the existing mobile phone base station as reference. The barometric measurement data from the densely distributed mobile phone base stations would be broadcasted to the adjacent user receiver. Absolute elevation value of the user receiver would be calculated by using relative formula combining the barometric pressure values and temperature values in the mobile phone base stations with the measured point. Experimental tests indicate that the indoor elevation positioning accuracy is about 1 m and the outdoor is less than 1 m. The resolution of barometric altimetry is about 0.2 m. Three-dimensional positioning accuracy of global navigation satellite system(GNSS) increase by about 60%. This method that barometric altimetry can be taken as a constraint condition involved in the solution of measurement equations can not only compensate the poor elevation positioning accuracy, also overcome the traditional barometric altimetry depending on the weather stations where are far away from most of the user receivers. Therefore, this method can assist satellite navigation system, improve the three-dimensional positioning accuracy and solve the problem of resolution upstairs and downstairs.
Compressive behavior of composite cylinder shell with cover
Fan Zhou, Cheng Xiaoquan, Li Zhonghai, Hu Renwei
2013, (1): 89-94.
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The compressive behavior of one-third composite cylindrical shell with cover was studied. The composite cylinder shell with cover which was tested under compressive load failed in local buckling at 118.944 kN without post-buckling. The finite element model was built in ABAQUS to calculate buckling behavior of the composite cylindrical structure. The computational results were compared with experimental results to verify the validity of this finite element model. The built finite element model was utilized to investigate the method of improving buckling load of the structure. The results show that the layer angles of patch and cover have directly effect on the buckling load. If the angle of patch and cover change from 0皌o 20 ,the structure buckling load will improve 6.80% and 2.39%. The thickness of patch also has effect on the buckling load. However, increasing thickness of patch is not an ideal method to improve buckling load. Because when the number of the layers increases from 11 to 16, buckling load only improves by 2.37%. Considering the cost and weight, it is not a wise choice compared with changing layer angle.
Hot diaphragm forming of carbon fiber composite with C-shaped structure
Yao Shuang, Li Min, Gu Yizhuo, Ma Xiaoxing
2013, (1): 95-99,104.
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The device of hot diaphragm forming was designed. The preforms of carbon fiber composite with C-shape structure were fabricated. The variations of temperatures on the preforms and the mould were measured. Furthermore, the influences of the forming temperature and the size of perform on the processing quality and internal defect were investigated. It shows the combination of preheating of mould with the radiation heating effect during the hot diaphragm forming could guarantee the temperature of the prepreg distributes homogeneously. When the forming temperature is low, the viscidity of the prepreg is relatively great and the ability of slipping between prepreg is poor which cause the fiber wrinkle at the corner of preform and high poriness. In addition, the preform tends to warp, when the size of preform is close to that of the mould. This phenomenon results from the diaphragm bridging and large deformation of the preform, hence proper size proportion between preform and mould must be controlled.
Preparation of borate-based metal compounds and their electrocatalytic activities
Liu Yanjun, Jin Tao, Xiang Min, Diao Peng
2013, (1): 100-104.
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Borate-based metal compounds thin film such as cobalt-borate(CoBi), nickel-borate(NiBi), manganese-borate(MnBi), rhodium-borate(RhBi) and palladium-borate(PdBi) were prepared on the surface of indium tin oxide(ITO) through electrochemical method at room temperature in alkaline medium. These compounds were amorphous films by morphology and structure characterization. Comparing their catalytic activities in electrocatalytical water splitting for oxygen generation, CoBi, NiBi and RhBi show higher activity than MnBi and PdBi. Further research indicates that borate is beficial for the preparation of borate-based metal compounds, and as a proton acceptor, the concentration of HBO32- rised gradually as pH increases from 7 to 11, HBO32- can accept the proton produced from oxygen evolving process, improving the electrocatalytical water splitting. In addition, the as-synthesized catalysts could be self-repaired and recycled.
Flow visualization of supersonic optical dome with jet
Zhu Yangzhu, Yi Shihe, Tian Lifeng, Chen Zhi
2013, (1): 105-108.
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In the Mach 3.8 wind tunnel, fine structures in the flow field of optical dome with or without jet were studied by nano-tracer based planar laser scattering(NPLS), which has high spatiotemporal resolution. Lots of complex structures in the flow field were clearly visible, such as shock wave, expansion wave, shear layer and turbulent boundary layer. The analysis of time-correlated NPLS images revealed the temporal evolution characteristic of flow structures. The results show that most of flow above the optical window without jet cooling is laminar. The laminar zone with jet cooling is much shorter and transits to turbulence in a short distance. The transition point of the shear layer with higher pressure is closer to the injector exit, and the vortices are more complex. Compared to the former, the latter case will induce aero-optical effects even more.
Multi-source knowledge fusion algorithm
Zhou Fang, Wang Pengbo, Han Liyan
2013, (1): 109-114.
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Multiple source knowledge fusion can effectively enhance the reliability and credibility of the ruling result. In the light of information fusion, methods and general model of knowledge fusion were analyzed, with emphasis on knowledge fusion algorithms based on Bayes rule, Dempster-Shafer(D-S) proof theory and fuzzy sets theory. Explicit processing steps of the algorithms mentioned above were presented, and comparison between which from the perspectives of the characteristics, applicability wend practicability were drawn as well. Finally, the knowledge fusion algorithms based on Bayes theory was introduced into the field of synthetic aperture radar(SAR) image fusions. Simulation results show the effectiveness of the multiple source knowledge fusion algorithms.
Application of ADRC technology in electrohydraulic force servo system
Guo Dong, Fu Yongling, Lu Ning, Long Manlin
2013, (1): 115-119.
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To meet the performance requirements of electrohydraulic force servo system for the upset process of billet flash butt welding of the ending welding rolling, composite control strategy based on active disturbance rejection control (ADRC) technology and force synchronization errors feedback correction strategy were presented. Considering the nonlinear of the system, time-varying parameters and coupling arising from mechanical structure, the system model was built in AMESim. The system has the challenges entailed by the conditions such as the upset force to be loaded with big force value, the variable rigidity of the loading system, the synchrony requirement while the two cylinders loading with even load on each cylinder. The interference of hydraulic servo system should be eliminated. Aiming at to furnish a robust, quick response, and synchronous loading system, composite control strategy based on ADRC technology and proportional integral synchronization errors feedback correction was proposed. The effectiveness and feasibility of the composite control strategy are verified through simulation research of a quick and big load servo with impulse.
Dynamic modeling of combined reaction wheel and vibration isolation platform system
Huang Tingxuan, Zhang Yao, Xu Shijie
2013, (1): 120-125.
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To analyze the attenuation effect of vibration isolation platform for reaction wheel (RW) disturbances, the dynamic modeling problem of the combined system which includes an imbalance RW and a passive Stewart platform with kinetic base platform was studied. The precise dynamics formulation was derived. The equations show that there are coupling effects between the RW and the platform, and rotor imbalance can also produce additional coupling disturbances other than tonal disturbances. The magnitudes of these disturbances were investigated and a reduction of the system model was made accordingly. Numerical simulations were conducted to compare the reduced system model to the complete one, which check the validity of the reduced model. And a primary simulation for whole spacecraft system shows that the vibration isolation system could improve the attitude stability effectively.
Robust matching design optimization for wing aerodynamic characteristic of aircraft family
Meng Wengong, Ma Dongli
2013, (1): 126-131.
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The wing component is served as a common module and sharing in every model of modern aircraft family. Due to the different mission of every model, the aerodynamic requirement of wing in the aircraft family is different. The design-ratio was inducted and the matching design optimization concept for the wing aerodynamic characteristics was presented. The corresponding models with the parameter of the model design-ratio were established. The impact of the uncertainty of the design-ratio acting on the wing aerodynamic was analyzed. The model of robust matching design optimization (RMDO) for the functional module characteristics of the aircraft family was built. RMDO for the wing aerodynamic characteristics of a transonic aircraft family with two models was accomplished. The results indicate that the wing aerodynamic difference of every model in the aircraft family and the impact of the uncertainty of the design-ratio acting on the wing aerodynamic reduce based on RMDO. And the aerodynamic performance of the aircraft is improved.
Spinning missile dynamic inversion controller robustness analysis using Lyapunov methods
Liu Fang, Chen Wanchun
2013, (1): 132-137.
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A two time-scale separation based nonlinear dynamic inversion controller was designed for the spinning missile. A state-space formulation of the control system with the aerodynamic coefficient uncertainties was presented. The nonlinear controller robustness was analyzed using Lyapunov methods. Associating with the actuator's capability, the bound of inner loop time constant was obtained. The aerodynamic coefficient uncertainties boundary was calculated. The result demonstrates that the advisable range of inner loop time constant is large when the uncertainties vary to make the airframe static stable, vice versa. The controller becomes more sensitive against the uncertainties when the inner and outer loop time constant scale increases. Comparing with the three loop controller, the dynamic inversion controller is less robust, but more stable.
Control strategy for electro-mechanical braking based on curves of ECE regulations and ideal braking force
Liu Lijun, Ji Fenzhu, Yang Shichun, Xu Bin
2013, (1): 138-142.
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The braking system of electric vehicle with regenerative braking is different from friction braking system of conventional fuel vehicle. Regenerative braking system makes braking stability of electric vehicles change when it recovers braking energy of vehicles. The improvement of braking energy recovery ration was restricted by the braking stability under the precondition of safe braking distance. Aiming at the electro-mechanical hybrid braking system composed of electric braking and conventional friction braking, the calculation models of electric braking force, electric braking torque and battery charging power were established. In view of the motor torque characteristics and battery charging power limit, three kinds of control strategies for electro-mechanical hybrid braking were designed for recovering the maximal braking energy. The baking energy recovery ration, state of charge and driving range in pure electric mode were calculated and analyzed by embedding simulation module into the ADVISOR. The calculation results show that the curves of I and economic commission of europe (ECE) regulations boundary are not ideal curves of braking force distribution; the curve OABCD is more feasible; the braking energy recovery ratio should be reached 59.56% by OABCD; and the state of charge changes very little; it decreases only by 4.29%.The test data indicates that the driving range can be increased by energy callback.

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