This paper studies a conformal invariance and an integration of first-order differential equations. It obtains the corresponding infinitesimal generators of conformal invariance by using the symmetry of the differenti...This paper studies a conformal invariance and an integration of first-order differential equations. It obtains the corresponding infinitesimal generators of conformal invariance by using the symmetry of the differential equations, and expresses the differential equations by the equations of a Birkhoff system or a generalized Birkhoff system. If the infinitesimal generators are those of a Noether symmetry, the conserved quantity can be obtained by using the Noether theory of the Birkhoff system or the generalized Birkhoff system.展开更多
Abstract： Based on digital signal processor（DSP） and field programmable gate array（FPGA） techniques, the architecture of super large view field（SLVF） panoramic night vision image processing hardware platform wa...Abstract： Based on digital signal processor（DSP） and field programmable gate array（FPGA） techniques, the architecture of super large view field（SLVF） panoramic night vision image processing hardware platform was established. The panoramic unwrapping and correcting algorithm, up to a full 360°, based on coordinate rotation digital computer （CORDIC） and night vision image enhancement algorithm, based on histogram equalization theory and edge detection theory, was presented in this paper, with the purpose of processing night vision dynamic panoramic annular image. The annular image can be unwrapped and corrected to conventional rectangular panorama by the panoramic image processing algorithm, which uses the pipelined CORDIC configuration to realize a trigonometric function generator with high speed and high precision. Histogram equalization algorithm can perfectly enhance the contrast of the night vision image. Edge detection algorithm can be propitious to find and detect small dim dynamic targets in night vision circumstances. After abundant experiment, the al- gorithm for panoramic image processing and night vision image enhancement is successfully implemented in FPGA and DSP. The panoramic night vision image system is a compact device, with no external rotating parts. And the system can reliably and dynamically detect 360＊ SLVF panoramic night vision image.展开更多
The performance characteristics of an axial-flow pump with tandem blades are studied based on the numerical computations. The arrangement of the pump impellers is established through the analysis of velocity triangles...The performance characteristics of an axial-flow pump with tandem blades are studied based on the numerical computations. The arrangement of the pump impellers is established through the analysis of velocity triangles. With the commercial computational fluid dynamics (CFD) software NUMECA, the turbulent flow in the tandem axial-flow pump is simulated in various flow conditions. The detail flow structure in the leading edge region of the rear impeller is described, and the influence of the deflection angle of the rear blade on the head performance is studied. According to the simulation, the performance comparison is made between the tandem axial-flow pump and the conventional two-stage axial-flow pump with a uniform impeller size. Results of the study indicate that the tandem axial-flow pump can work in a wider range with high efficiency.展开更多
Feature selection is an important problem in pattern classification systems. High dimension fisher criterion（HDF） is a good indicator of class separability. However, calculating the high dimension fisher ratio is di...Feature selection is an important problem in pattern classification systems. High dimension fisher criterion（HDF） is a good indicator of class separability. However, calculating the high dimension fisher ratio is difficult. A new feature selection method, called fisher-and-correlation （FC）, is proposed. The proposed method is combining fisher criterion and correlation criterion based on the analysis of feature relevance and redundancy. The proposed methodology is tested in five different classification applications. The presented resuits confirm that FC performs as well as HDF does at much lower computational complexity.展开更多
According to the necessary condition of the functional taking the extremum, that is its first variation is equal to zero, the variational problems of the functionals for the undetermined boundary in the calculus of va...According to the necessary condition of the functional taking the extremum, that is its first variation is equal to zero, the variational problems of the functionals for the undetermined boundary in the calculus of variations are researched, the functionals depend on single argument, arbitrary unknown functions and their derivatives of higher orders. A new view point is posed and demonstrated, i.e. when the first variation of the functional is equal to zero, all the variational terms are not independent to each other, and at least one of them is equal to zero. Some theorems and corollaries of the variational problems of the functionals are obtained.展开更多
The plane medium and point charge are regarded as an integral system. The static field＇s distribution situation of the point charge is studied in the medium structure of plane division layers by using mirror image me...The plane medium and point charge are regarded as an integral system. The static field＇s distribution situation of the point charge is studied in the medium structure of plane division layers by using mirror image method, drawing the point charge＇s calculation expression of the electric potential in every medium space. The mathematics model of passive electrostatic detecting people through the medium （regular distance between the goal point charge and the medium） is established, using MATLAB software to carry out emulation of the model and analysing the result, establishing the theoretical foundation for studying the technology of the passive static detecting people through the wall.展开更多
For the strong coupling among the channels of bank-to-turn （BTT） missile with high-aspect-ratio wing, an autopilot is designed with a two loop control structure robust autopilot design methods. By the inner loop des...For the strong coupling among the channels of bank-to-turn （BTT） missile with high-aspect-ratio wing, an autopilot is designed with a two loop control structure robust autopilot design methods. By the inner loop design, the question of pole-zero cancellation is solved, and the stabilization of structured uncertainty is achieved. Through the outer loop of H∞ controller design, the flying performance and robustness can be guaranteed. The nonlinear simulation results show that the autopilot designed has perfect time domain response, and can suppress bad influence of the inertial and kinematics couplings. It can make the missile fly stably in the large flying areas. The control is very effective.展开更多
The microscopic structures and the bonding properties of Y-doped and undoped （011^-8）/[044^-1]/180° （∑37） grain boundaries in alumina are investigated by using ab initio method. The formation energy of grain...The microscopic structures and the bonding properties of Y-doped and undoped （011^-8）/[044^-1]/180° （∑37） grain boundaries in alumina are investigated by using ab initio method. The formation energy of grain boundary and the segregation energy of Y to grain boundary are acquired. Electronic structures, potential distributions, bond orders and effective charges of Y-doped and undoped ∑37 GB systems are calculated. Our results reveal that the higher strength Y-O bond than Al-O bond is ascribed to the hybridization of Y（4p, 3d） with O（2s）. Meanwhile, dopant Y also causes a change in potential distribution in the grain boundary region, thereby further affecting the transport property of ceramic alumina.展开更多
A system for simulating and analyzing the Doppler signal of air-target fuse is established by constructing two parts： Doppler signal testing with simulation and Doppler signal analysis. The first part establishes the...A system for simulating and analyzing the Doppler signal of air-target fuse is established by constructing two parts： Doppler signal testing with simulation and Doppler signal analysis. The first part establishes the near-field target characteristic model where the Doppler spectrum in different encounter condition is obtained. The second part mainly deals with a general purpose hardware platform to obtain and process the Doppler signal as well as a software to estimate the Doppler spectrum. The model and the result of Doppler spectrum analysis were verified by experiments.展开更多
The operational principle, the impulse force and terminal guidance laws of terminal correction mortar projectiles（TCMP） are researched in this paper, by using the TCMP simulation program, key techniques such as the ...The operational principle, the impulse force and terminal guidance laws of terminal correction mortar projectiles（TCMP） are researched in this paper, by using the TCMP simulation program, key techniques such as the miss distance influenced by the acting point of impulse force, the impulse force value, the correction threshold, and the number of impulse rockets are researched in this paper. And the dual pulse control scheme is also studied. Simulation results indicate that the best acting point is near the center of gravity, sufficient correction resources are needed, the miss distance is insentive to the correction threshold, increasing the number of impulse rockets properly is beneficial to increase the hit precision, the velocity pursuit guidance law has less miss distance, the change of the attack angle is milder and the transient time becomes less in the dual impulse control scheme. These conclusions are important for choosing parameters and impulse correction schemes designed for TCMP.展开更多
A new method called critical suction is used based on the wall climbing robot demands of miniature structure, moving smartly and low noise. It makes the robot achieve the homeostasis state in the suction cup, and in t...A new method called critical suction is used based on the wall climbing robot demands of miniature structure, moving smartly and low noise. It makes the robot achieve the homeostasis state in the suction cup, and in this condition the robot can stay on the wall reliably and move smartly. The fluid mechanics model and fluid network model are set up to analyze the robot suction system when the airflow is steady or changes suddenly. Furthermore, simulation results indicate the close relation between the key parameters of robot structure and the suction system. Finally the method of critical suction proves correct in theory.展开更多
The motion planning for obstacle negotiation by humanoid robot BHR-2 through stepping over or stepping on/off the wide and flat obstacle at known locations is presented. In the trajectory generation method, first the ...The motion planning for obstacle negotiation by humanoid robot BHR-2 through stepping over or stepping on/off the wide and flat obstacle at known locations is presented. In the trajectory generation method, first the constraints of the foot motion parameters which include obstacle dimensions and the distance of obstacle from the humanoid robot is formulated. By varying the values of the constraint parameters, different types of foot motion for different obstacles can be produced. In this method, first the foot trajectory is generated, and then the waist trajectory is computed by using cubic spline interpolation without first calculating the zero moment point （ZMP） trajectory . The dynamic stability during the execution of stepping over and stepping on/off trajectories are ensured by incorporating the ZMP criterion. The effectiveness of the proposed method is confirmed by simulations and experiments on humanoid robot BHR-2.展开更多
The system composition, the operational principle of terminal correction mortar projectiles （TCMP） and the concept planning design of TCMP are researched in this paper. An overall design and aerodynamic configuratio...The system composition, the operational principle of terminal correction mortar projectiles （TCMP） and the concept planning design of TCMP are researched in this paper. An overall design and aerodynamic configuration layout for TCMP are made in this paper, and its aerodynamic coefficients are calculated by using computational fluid dynamics （CFD） software. Test results of TCMP simulated ballistic projectiles indicate the designed TCMP can satisfy the interior ballistic demand and has a fine flight stability. The drag coefficients identified from the radar velocity-time data are in accord with the CFD computed results. According to the exposure frequency of the ground laser designator, a four-quadrant impulse correction scheme and a high exposure frequency impulse correction scheme are brought. The latter can calculate the target azimuth angle by counting the times of the facula passing through one quadrant. Simulation results also show that the guidance precision of the velocity pursuit is higher than that of the body pursuit, and the detector axis is less circuitous. Researches on the typical trajectory indicate that the terminal impulse correction can improve the hit precision of TCMP remarkably.展开更多
The alignment accuracy of the strap-down inertial navigation system （SINS） of airborne weapon is greatly degraded by the dynamic wing flexure of the aircraft. An adaptive Kalman filter uses innovation sequences base...The alignment accuracy of the strap-down inertial navigation system （SINS） of airborne weapon is greatly degraded by the dynamic wing flexure of the aircraft. An adaptive Kalman filter uses innovation sequences based on the maximum likelihood estimated criterion to adapt the system noise covariance matrix and the measurement noise covariance matrix on line, which is used to estimate the misalignment if the model of wing flexure of the aircraft is unknown. From a number of simulations, it is shown that the accuracy of the adaptive Kalman filter is better than the conventional Kalman filter, and the erroneous misalignment models of the wing flexure of aircraft will cause bad estimation results of Kalman filter using attitude match method.展开更多
The alternate location method of a robot team is proposed. Three of the robots are kept still as beacon robots, not always the same ones, while the others are regarded as mobile robots. The mobile robots alternatively...The alternate location method of a robot team is proposed. Three of the robots are kept still as beacon robots, not always the same ones, while the others are regarded as mobile robots. The mobile robots alternatively measure the distance between one of them and three beacon robots with ultrasonic measurement module. The distance data are combined with its dead-reckoning information using iterated extended Kalrnan filter （IEKF） to realize the optimal estimate of its position. According to the condition the future beacon robots＇ positions should be desired ones, the target function and the nonlinear constrain equations are set up which are used by nonlinear optimization algorithm to estimate the position of the future beacon robots. By alternately changing the robots＇ roles as active beacon, the alternate location in unknown environment can＇be realized. Process and result of the simulation test are given and the position estimation error is within ＋ 10 ram, which proves the validity of this method.展开更多
A numerical calculation method based on the finite element analysis of dynamic characteristics of artillery-fuze system is discussed in detail. Pretension element is used to mesh the couple structure between artillery...A numerical calculation method based on the finite element analysis of dynamic characteristics of artillery-fuze system is discussed in detail. Pretension element is used to mesh the couple structure between artillery and fuze to analyze the change of dynamic characteristics of artillery-fuze system when pre-tightening force varies between artillery and fuze. Numerical calculation of the finite element analysis and actual hammering test of a artillery-fuze system are carried out with the same input to verify the accuracy of numerical calculation. The results show that the finite element model of artillery-fuze system is credible and the calculation accuracy is perfect.展开更多
The method which can simulate the stochastic process of the overload during the course of a projectile launching is discussed in detail. The calculated theory bases on the principle of information diffusion in fuzzy t...The method which can simulate the stochastic process of the overload during the course of a projectile launching is discussed in detail. The calculated theory bases on the principle of information diffusion in fuzzy theory. To approach the actual launching overload, the calculated theoretical overload is disposed by the white noise. The dynamic test is used to calculate the fuze response of the launching overload. Finally, the launching overload of a projectile fuze is simulated to verify the validity of the method. The result is found basically to be in accord with the actual launching overload of the fuze, and the calculation accuracy is perfect.展开更多
This paper studies integration of a higher-order differential equation which can be reduced to a second-order ordinary differential equation. The solution of the second-order equation can be obtained by the Noether me...This paper studies integration of a higher-order differential equation which can be reduced to a second-order ordinary differential equation. The solution of the second-order equation can be obtained by the Noether method and the Poisson method. Then the solution of the higher-order equation can be obtained by integrating the solution of the second-order equation.展开更多
The dynamic characteristics of acceleration autopilot and attitude autopilot are discu.ssed in detail. Also, a comparison study was made between these two different types of control schemes for guidance loop. By means...The dynamic characteristics of acceleration autopilot and attitude autopilot are discu.ssed in detail. Also, a comparison study was made between these two different types of control schemes for guidance loop. By means of simulation, it is concluded that the guidance accuracy is mainly determined by the slowest subsystem among different system dynamics. For air-to-ground missiles, with limited terminal guidance time, the control scheme of acceleration autopilot combined with proportional navigation guidance （PNG） law is the better choice.展开更多
Basing on the explicit instantaneous dynamics software MSC-Dytran and the general coupling arithmetic, the process of the projectile penetration into concrete target was simulated with the point-line-surfacebody model...Basing on the explicit instantaneous dynamics software MSC-Dytran and the general coupling arithmetic, the process of the projectile penetration into concrete target was simulated with the point-line-surfacebody modeling method. Simulation results are in agreement with experimental results. The simulated data could provide design reference for the defense engineering construction and penetrator design.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos 10572021 and 10772025)the Doctoral Programme Foundation of Institution of Higher Education of China (Grant No 20040007022)
文摘This paper studies a conformal invariance and an integration of first-order differential equations. It obtains the corresponding infinitesimal generators of conformal invariance by using the symmetry of the differential equations, and expresses the differential equations by the equations of a Birkhoff system or a generalized Birkhoff system. If the infinitesimal generators are those of a Noether symmetry, the conserved quantity can be obtained by using the Noether theory of the Birkhoff system or the generalized Birkhoff system.
文摘Abstract： Based on digital signal processor（DSP） and field programmable gate array（FPGA） techniques, the architecture of super large view field（SLVF） panoramic night vision image processing hardware platform was established. The panoramic unwrapping and correcting algorithm, up to a full 360°, based on coordinate rotation digital computer （CORDIC） and night vision image enhancement algorithm, based on histogram equalization theory and edge detection theory, was presented in this paper, with the purpose of processing night vision dynamic panoramic annular image. The annular image can be unwrapped and corrected to conventional rectangular panorama by the panoramic image processing algorithm, which uses the pipelined CORDIC configuration to realize a trigonometric function generator with high speed and high precision. Histogram equalization algorithm can perfectly enhance the contrast of the night vision image. Edge detection algorithm can be propitious to find and detect small dim dynamic targets in night vision circumstances. After abundant experiment, the al- gorithm for panoramic image processing and night vision image enhancement is successfully implemented in FPGA and DSP. The panoramic night vision image system is a compact device, with no external rotating parts. And the system can reliably and dynamically detect 360＊ SLVF panoramic night vision image.
基金Sponsored bythe National Natural Science Foundation of China(50679001) the Basic Research Foundation of Beijing Institute of Technology(20060342001)
文摘The performance characteristics of an axial-flow pump with tandem blades are studied based on the numerical computations. The arrangement of the pump impellers is established through the analysis of velocity triangles. With the commercial computational fluid dynamics (CFD) software NUMECA, the turbulent flow in the tandem axial-flow pump is simulated in various flow conditions. The detail flow structure in the leading edge region of the rear impeller is described, and the influence of the deflection angle of the rear blade on the head performance is studied. According to the simulation, the performance comparison is made between the tandem axial-flow pump and the conventional two-stage axial-flow pump with a uniform impeller size. Results of the study indicate that the tandem axial-flow pump can work in a wider range with high efficiency.
基金the Ministerial Level Advanced Research Foundation(66830202)
文摘Feature selection is an important problem in pattern classification systems. High dimension fisher criterion（HDF） is a good indicator of class separability. However, calculating the high dimension fisher ratio is difficult. A new feature selection method, called fisher-and-correlation （FC）, is proposed. The proposed method is combining fisher criterion and correlation criterion based on the analysis of feature relevance and redundancy. The proposed methodology is tested in five different classification applications. The presented resuits confirm that FC performs as well as HDF does at much lower computational complexity.
文摘According to the necessary condition of the functional taking the extremum, that is its first variation is equal to zero, the variational problems of the functionals for the undetermined boundary in the calculus of variations are researched, the functionals depend on single argument, arbitrary unknown functions and their derivatives of higher orders. A new view point is posed and demonstrated, i.e. when the first variation of the functional is equal to zero, all the variational terms are not independent to each other, and at least one of them is equal to zero. Some theorems and corollaries of the variational problems of the functionals are obtained.
文摘The plane medium and point charge are regarded as an integral system. The static field＇s distribution situation of the point charge is studied in the medium structure of plane division layers by using mirror image method, drawing the point charge＇s calculation expression of the electric potential in every medium space. The mathematics model of passive electrostatic detecting people through the medium （regular distance between the goal point charge and the medium） is established, using MATLAB software to carry out emulation of the model and analysing the result, establishing the theoretical foundation for studying the technology of the passive static detecting people through the wall.
文摘For the strong coupling among the channels of bank-to-turn （BTT） missile with high-aspect-ratio wing, an autopilot is designed with a two loop control structure robust autopilot design methods. By the inner loop design, the question of pole-zero cancellation is solved, and the stabilization of structured uncertainty is achieved. Through the outer loop of H∞ controller design, the flying performance and robustness can be guaranteed. The nonlinear simulation results show that the autopilot designed has perfect time domain response, and can suppress bad influence of the inertial and kinematics couplings. It can make the missile fly stably in the large flying areas. The control is very effective.
基金supported by the National Natural Science Foundation of China (Grant Nos 10744002 and 10774017)supported by the Supercomputing Centre of Chinese Academy of Sciences (SCCAS)
文摘The microscopic structures and the bonding properties of Y-doped and undoped （011^-8）/[044^-1]/180° （∑37） grain boundaries in alumina are investigated by using ab initio method. The formation energy of grain boundary and the segregation energy of Y to grain boundary are acquired. Electronic structures, potential distributions, bond orders and effective charges of Y-doped and undoped ∑37 GB systems are calculated. Our results reveal that the higher strength Y-O bond than Al-O bond is ascribed to the hybridization of Y（4p, 3d） with O（2s）. Meanwhile, dopant Y also causes a change in potential distribution in the grain boundary region, thereby further affecting the transport property of ceramic alumina.
文摘A system for simulating and analyzing the Doppler signal of air-target fuse is established by constructing two parts： Doppler signal testing with simulation and Doppler signal analysis. The first part establishes the near-field target characteristic model where the Doppler spectrum in different encounter condition is obtained. The second part mainly deals with a general purpose hardware platform to obtain and process the Doppler signal as well as a software to estimate the Doppler spectrum. The model and the result of Doppler spectrum analysis were verified by experiments.
基金Sponsored by the Ministerial Level Advanced Research Foundation (40406030101)
文摘The operational principle, the impulse force and terminal guidance laws of terminal correction mortar projectiles（TCMP） are researched in this paper, by using the TCMP simulation program, key techniques such as the miss distance influenced by the acting point of impulse force, the impulse force value, the correction threshold, and the number of impulse rockets are researched in this paper. And the dual pulse control scheme is also studied. Simulation results indicate that the best acting point is near the center of gravity, sufficient correction resources are needed, the miss distance is insentive to the correction threshold, increasing the number of impulse rockets properly is beneficial to increase the hit precision, the velocity pursuit guidance law has less miss distance, the change of the attack angle is milder and the transient time becomes less in the dual impulse control scheme. These conclusions are important for choosing parameters and impulse correction schemes designed for TCMP.
基金Sponsored byt he Scientific Research Foundation for Returned Overseas Chinese Scholars ,State Education Ministry(20060232001)
文摘A new method called critical suction is used based on the wall climbing robot demands of miniature structure, moving smartly and low noise. It makes the robot achieve the homeostasis state in the suction cup, and in this condition the robot can stay on the wall reliably and move smartly. The fluid mechanics model and fluid network model are set up to analyze the robot suction system when the airflow is steady or changes suddenly. Furthermore, simulation results indicate the close relation between the key parameters of robot structure and the suction system. Finally the method of critical suction proves correct in theory.
基金Sponsored by the National"863"Program Project (1020021300704)
文摘The motion planning for obstacle negotiation by humanoid robot BHR-2 through stepping over or stepping on/off the wide and flat obstacle at known locations is presented. In the trajectory generation method, first the constraints of the foot motion parameters which include obstacle dimensions and the distance of obstacle from the humanoid robot is formulated. By varying the values of the constraint parameters, different types of foot motion for different obstacles can be produced. In this method, first the foot trajectory is generated, and then the waist trajectory is computed by using cubic spline interpolation without first calculating the zero moment point （ZMP） trajectory . The dynamic stability during the execution of stepping over and stepping on/off trajectories are ensured by incorporating the ZMP criterion. The effectiveness of the proposed method is confirmed by simulations and experiments on humanoid robot BHR-2.
基金the Ministerial Level Advanced Research Foundation (40406030101)
文摘The system composition, the operational principle of terminal correction mortar projectiles （TCMP） and the concept planning design of TCMP are researched in this paper. An overall design and aerodynamic configuration layout for TCMP are made in this paper, and its aerodynamic coefficients are calculated by using computational fluid dynamics （CFD） software. Test results of TCMP simulated ballistic projectiles indicate the designed TCMP can satisfy the interior ballistic demand and has a fine flight stability. The drag coefficients identified from the radar velocity-time data are in accord with the CFD computed results. According to the exposure frequency of the ground laser designator, a four-quadrant impulse correction scheme and a high exposure frequency impulse correction scheme are brought. The latter can calculate the target azimuth angle by counting the times of the facula passing through one quadrant. Simulation results also show that the guidance precision of the velocity pursuit is higher than that of the body pursuit, and the detector axis is less circuitous. Researches on the typical trajectory indicate that the terminal impulse correction can improve the hit precision of TCMP remarkably.
文摘The alignment accuracy of the strap-down inertial navigation system （SINS） of airborne weapon is greatly degraded by the dynamic wing flexure of the aircraft. An adaptive Kalman filter uses innovation sequences based on the maximum likelihood estimated criterion to adapt the system noise covariance matrix and the measurement noise covariance matrix on line, which is used to estimate the misalignment if the model of wing flexure of the aircraft is unknown. From a number of simulations, it is shown that the accuracy of the adaptive Kalman filter is better than the conventional Kalman filter, and the erroneous misalignment models of the wing flexure of aircraft will cause bad estimation results of Kalman filter using attitude match method.
文摘The alternate location method of a robot team is proposed. Three of the robots are kept still as beacon robots, not always the same ones, while the others are regarded as mobile robots. The mobile robots alternatively measure the distance between one of them and three beacon robots with ultrasonic measurement module. The distance data are combined with its dead-reckoning information using iterated extended Kalrnan filter （IEKF） to realize the optimal estimate of its position. According to the condition the future beacon robots＇ positions should be desired ones, the target function and the nonlinear constrain equations are set up which are used by nonlinear optimization algorithm to estimate the position of the future beacon robots. By alternately changing the robots＇ roles as active beacon, the alternate location in unknown environment can＇be realized. Process and result of the simulation test are given and the position estimation error is within ＋ 10 ram, which proves the validity of this method.
基金the Ministerial Level Advanced Research Foundation (5140C9384029389C475)
文摘A numerical calculation method based on the finite element analysis of dynamic characteristics of artillery-fuze system is discussed in detail. Pretension element is used to mesh the couple structure between artillery and fuze to analyze the change of dynamic characteristics of artillery-fuze system when pre-tightening force varies between artillery and fuze. Numerical calculation of the finite element analysis and actual hammering test of a artillery-fuze system are carried out with the same input to verify the accuracy of numerical calculation. The results show that the finite element model of artillery-fuze system is credible and the calculation accuracy is perfect.
基金Sponsored by the Ministerial Level Advanced Research Foundation (5140C9384029389C475)
文摘The method which can simulate the stochastic process of the overload during the course of a projectile launching is discussed in detail. The calculated theory bases on the principle of information diffusion in fuzzy theory. To approach the actual launching overload, the calculated theoretical overload is disposed by the white noise. The dynamic test is used to calculate the fuze response of the launching overload. Finally, the launching overload of a projectile fuze is simulated to verify the validity of the method. The result is found basically to be in accord with the actual launching overload of the fuze, and the calculation accuracy is perfect.
基金Project supported by the National Natural Science Foundation of China(Grant No10572021)Doctoral Programme Foundation of Institution of Higher Education of China(Grant No20040007022)
文摘This paper studies integration of a higher-order differential equation which can be reduced to a second-order ordinary differential equation. The solution of the second-order equation can be obtained by the Noether method and the Poisson method. Then the solution of the higher-order equation can be obtained by integrating the solution of the second-order equation.
文摘The dynamic characteristics of acceleration autopilot and attitude autopilot are discu.ssed in detail. Also, a comparison study was made between these two different types of control schemes for guidance loop. By means of simulation, it is concluded that the guidance accuracy is mainly determined by the slowest subsystem among different system dynamics. For air-to-ground missiles, with limited terminal guidance time, the control scheme of acceleration autopilot combined with proportional navigation guidance （PNG） law is the better choice.
基金Sponsored by the Ministerial Level Advanced Research Foundation (51309)
文摘Basing on the explicit instantaneous dynamics software MSC-Dytran and the general coupling arithmetic, the process of the projectile penetration into concrete target was simulated with the point-line-surfacebody modeling method. Simulation results are in agreement with experimental results. The simulated data could provide design reference for the defense engineering construction and penetrator design.
