Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and ev...Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.展开更多
The flow between a grooved and a flat plate was presented to investigate the effects of groove on the behavior of hydro-viscous drive. The flow was solved by using computational fluid dynamics (CFD) code, Fluent. Para...The flow between a grooved and a flat plate was presented to investigate the effects of groove on the behavior of hydro-viscous drive. The flow was solved by using computational fluid dynamics (CFD) code, Fluent. Parameters related to the flow, such as velocity, pressure, temperature, axial force and viscous torque, are obtained. The results show that pressure at the upstream notch is negative, pressure at the downstream notch is positive and pressure along the film thickness is almost the same. Dynamic pressure peak decreases as groove depth or groove number increases, but increases as output rotary speed increases. Consequently, the groove depth is suggested to be around 0.4 mm. Both the groove itself and groove parameters (i.e. groove depth, groove number) have little effect on the flow temperature. Circumferential pressure gradient induced by the groove weakens the viscous torque on the grooved plate (driven plate) greatly. It has little change as the groove depth increases. However, it decreases dramatically as the groove number increases. The experiment results show that the trend of experimental temperature and pressure are the same with numerical results. And the output rotary speed also has relationship with input flow rate and flow temperature.展开更多
In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely used.Researches are made to analyze the kinematic and compliance model of the r...In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely used.Researches are made to analyze the kinematic and compliance model of the robot joint with harmonic drive to acquire high precision torque output.Through analyzing the structures of the harmonic drive and experiment apparatus,a scheme of the proposed joint torque estimation method based on both the dynamic characteristics and unscented Kalman filter(UKF)is designed and built.Based on research and scheme,torque estimation methods in view of only harmonic drive compliance model and compliance model with the Kalman filter are simulated as guidance and reference to promote the research on the torque estimation technique.Finally,a promoted torque estimation method depending on both harmonic drive compliance model and UKF is designed,and simulation results compared with the measurements of a commercial torque sensor,have verified the effectiveness of the proposed method.展开更多
Laptop personal computers(LPCs) and their components are vulnerable devices in harsh mechanical environments. One of the most sensitive components of LPCs is hard disk drive(HDD) which needs to be protected against da...Laptop personal computers(LPCs) and their components are vulnerable devices in harsh mechanical environments. One of the most sensitive components of LPCs is hard disk drive(HDD) which needs to be protected against damages attributable to shock and vibration in order to have better magnetic read/write performance. In the present work, a LPC and its HDD are modeled as two degrees of freedom system and the nonlinear optimization method is employed to perform a passive control through minimizing peak of HDD absolute acceleration caused by a base shock excitation. The presented shock excitation is considered as half-sine pulse of acceleration. In addition, eleven inequality constraints are defined based on geometrical limitations and allowable intervals of lumped modal parameters. The target of the optimization is to reach optimum modal parameters of rubber mounts and rubber feet as design variables and subsequently propose new characteristics of rubber mounts and rubber feet to be manufactured for the HDD protection against shock excitation. The genetic algorithm and the modified constrained steepest descent algorithm are employed in order to solve the nonlinear optimization problem for three widely-used commercial cases of HDD. Finally, the results of both optimization methods are compared to make sure about their accuracy.展开更多
A kind of single impulse welding drive axle used in a truck was selected as research object.The dynamic characteristic simulation of the drive axle was analyzed through building the vehicle dynamics simulation model i...A kind of single impulse welding drive axle used in a truck was selected as research object.The dynamic characteristic simulation of the drive axle was analyzed through building the vehicle dynamics simulation model in virtual software.Comparison between different speeds and different roads were made to get the corresponding dynamics of drive axle.展开更多
In many cases, the cutting method is usually adopted for the efficient machining of non-circular body of revolution and a feed drive is needed to actuate the cutting tool to and fro according to input signal wave. The...In many cases, the cutting method is usually adopted for the efficient machining of non-circular body of revolution and a feed drive is needed to actuate the cutting tool to and fro according to input signal wave. The feed drive for the purpose is required of fast response and accurate positioning. Both of these are highly dependent upon the actuating elements. Several schemes of actuation are specially interested. One is the introduction of piezoelectric actuation. However, the tiny working stroke of the piezoelectric material limits its application to a narrow range. Another is the application of electro-magnetic actuator. An innovative feed drive actuated by the stepper motor is introduced for the purpose. For a conventional step operating mode, a stepper motor can only be controlled to position at finite discrete points. Thus, when it is applied as an actuator of the feed drive, it is very difficult to maintain high accuracy and fast response. To eliminate quantitative error, the stepper motor is controlled under the continual mode. It is achieved with a micro-controller system and a built-in control algorithm program, called "tracking algorithm". Within each sampling cycle, the micro-controller will sample the input signal and the time interval will be divided into two parts according to the relative position between two adjacent stepping points. The phase coils correspondent to the two adjacent stepping points are energized respectively with calculated time duration. In the way, the motion of the tool frame smoothly tracks the input signal. This paper presents modeling and identification of frequency response of the proposed drive. The dynamic response of the feed drive is manly decided by the natural frequency of the stepper motor. For the conventional small-size stepper motors, the natural frequency is within the range 200～400 Hz. Experimental results show that the stepper motor actuated tool frame can smoothly keep in track of the input signal wave under "tracking control". The bandwidth of frequency of the feed drive exceeds 310 Hz.展开更多
The principle of rotor flux-orientation vector control on 100/150 kW three-phase AC induction motor for electric drive tracked vehicles is analyzed, and the mathematic model is deduced. The drive system of induction m...The principle of rotor flux-orientation vector control on 100/150 kW three-phase AC induction motor for electric drive tracked vehicles is analyzed, and the mathematic model is deduced. The drive system of induction motor is modeled and simulated by Matlab/Simulink. The characteristics of motor and drive system are analyzed and evaluated by practical bench test. The simulation and bench test results show that the model is valid, and the driving control system has constant torque under rated speed, constant torque above rated speed, widely variable speed range and better dynamic characteristics. In order to evaluate the practical applications of high power induction motor driving system in electric drive tracked vehicles, a collaborative simulation based on interface technology of Matlab/Simulink and multi-body dynamic analysis software known as RecurDyn is done, the vehicle performances are predicted in the acceleration time (0-32 km/h) and turning characteristic (v=10 km/h, R=B).展开更多
基金Supported by the National Natural Science Foundation of China (11161027)。
文摘Projective synchronization problems of a drive system and a particular response network were investigated,where the drive system is an arbitrary system with n+1 dimensions;it may be a linear or nonlinear system,and even a chaotic or hyperchaotic system,the response network is complex system coupled by N nodes,and every node is showed by the approximately linear part of the drive system.Only controlling any one node of the response network by designed controller can achieve the projective synchronization.Some numerical examples were employed to verify the effectiveness and correctness of the designed controller.
基金Project(50475106)supported by the National Natural Science Foundation of China
文摘The flow between a grooved and a flat plate was presented to investigate the effects of groove on the behavior of hydro-viscous drive. The flow was solved by using computational fluid dynamics (CFD) code, Fluent. Parameters related to the flow, such as velocity, pressure, temperature, axial force and viscous torque, are obtained. The results show that pressure at the upstream notch is negative, pressure at the downstream notch is positive and pressure along the film thickness is almost the same. Dynamic pressure peak decreases as groove depth or groove number increases, but increases as output rotary speed increases. Consequently, the groove depth is suggested to be around 0.4 mm. Both the groove itself and groove parameters (i.e. groove depth, groove number) have little effect on the flow temperature. Circumferential pressure gradient induced by the groove weakens the viscous torque on the grooved plate (driven plate) greatly. It has little change as the groove depth increases. However, it decreases dramatically as the groove number increases. The experiment results show that the trend of experimental temperature and pressure are the same with numerical results. And the output rotary speed also has relationship with input flow rate and flow temperature.
基金supported by the National Natural Science Foundation of China(51879055)。
文摘In the applications of joint control and robot movement,the joint torque estimation has been treated as an effective technique and widely used.Researches are made to analyze the kinematic and compliance model of the robot joint with harmonic drive to acquire high precision torque output.Through analyzing the structures of the harmonic drive and experiment apparatus,a scheme of the proposed joint torque estimation method based on both the dynamic characteristics and unscented Kalman filter(UKF)is designed and built.Based on research and scheme,torque estimation methods in view of only harmonic drive compliance model and compliance model with the Kalman filter are simulated as guidance and reference to promote the research on the torque estimation technique.Finally,a promoted torque estimation method depending on both harmonic drive compliance model and UKF is designed,and simulation results compared with the measurements of a commercial torque sensor,have verified the effectiveness of the proposed method.
文摘Laptop personal computers(LPCs) and their components are vulnerable devices in harsh mechanical environments. One of the most sensitive components of LPCs is hard disk drive(HDD) which needs to be protected against damages attributable to shock and vibration in order to have better magnetic read/write performance. In the present work, a LPC and its HDD are modeled as two degrees of freedom system and the nonlinear optimization method is employed to perform a passive control through minimizing peak of HDD absolute acceleration caused by a base shock excitation. The presented shock excitation is considered as half-sine pulse of acceleration. In addition, eleven inequality constraints are defined based on geometrical limitations and allowable intervals of lumped modal parameters. The target of the optimization is to reach optimum modal parameters of rubber mounts and rubber feet as design variables and subsequently propose new characteristics of rubber mounts and rubber feet to be manufactured for the HDD protection against shock excitation. The genetic algorithm and the modified constrained steepest descent algorithm are employed in order to solve the nonlinear optimization problem for three widely-used commercial cases of HDD. Finally, the results of both optimization methods are compared to make sure about their accuracy.
文摘A kind of single impulse welding drive axle used in a truck was selected as research object.The dynamic characteristic simulation of the drive axle was analyzed through building the vehicle dynamics simulation model in virtual software.Comparison between different speeds and different roads were made to get the corresponding dynamics of drive axle.
文摘In many cases, the cutting method is usually adopted for the efficient machining of non-circular body of revolution and a feed drive is needed to actuate the cutting tool to and fro according to input signal wave. The feed drive for the purpose is required of fast response and accurate positioning. Both of these are highly dependent upon the actuating elements. Several schemes of actuation are specially interested. One is the introduction of piezoelectric actuation. However, the tiny working stroke of the piezoelectric material limits its application to a narrow range. Another is the application of electro-magnetic actuator. An innovative feed drive actuated by the stepper motor is introduced for the purpose. For a conventional step operating mode, a stepper motor can only be controlled to position at finite discrete points. Thus, when it is applied as an actuator of the feed drive, it is very difficult to maintain high accuracy and fast response. To eliminate quantitative error, the stepper motor is controlled under the continual mode. It is achieved with a micro-controller system and a built-in control algorithm program, called "tracking algorithm". Within each sampling cycle, the micro-controller will sample the input signal and the time interval will be divided into two parts according to the relative position between two adjacent stepping points. The phase coils correspondent to the two adjacent stepping points are energized respectively with calculated time duration. In the way, the motion of the tool frame smoothly tracks the input signal. This paper presents modeling and identification of frequency response of the proposed drive. The dynamic response of the feed drive is manly decided by the natural frequency of the stepper motor. For the conventional small-size stepper motors, the natural frequency is within the range 200～400 Hz. Experimental results show that the stepper motor actuated tool frame can smoothly keep in track of the input signal wave under "tracking control". The bandwidth of frequency of the feed drive exceeds 310 Hz.
基金Sponsored by Ordnance Science and Technology Pre-research Project of China(40402070101)
文摘The principle of rotor flux-orientation vector control on 100/150 kW three-phase AC induction motor for electric drive tracked vehicles is analyzed, and the mathematic model is deduced. The drive system of induction motor is modeled and simulated by Matlab/Simulink. The characteristics of motor and drive system are analyzed and evaluated by practical bench test. The simulation and bench test results show that the model is valid, and the driving control system has constant torque under rated speed, constant torque above rated speed, widely variable speed range and better dynamic characteristics. In order to evaluate the practical applications of high power induction motor driving system in electric drive tracked vehicles, a collaborative simulation based on interface technology of Matlab/Simulink and multi-body dynamic analysis software known as RecurDyn is done, the vehicle performances are predicted in the acceleration time (0-32 km/h) and turning characteristic (v=10 km/h, R=B).
