Applied Mechanics and Materials Vols. 220-223

Abstract: High-speed permanent magnet synchronous motor (PMSM) is more and more widely applied in high precision processing and high-performance machines. It is very important to research practical control strategy for the stability operation of the high-speed PMSM. The strategy of sensorless grey prediction fuzzy direct torque control (DTC) is proposed which is suitable for high-speed PMSM control system. The method of prediction fuzzy control based on DTC is used to gain the flux, torque and flux oriented angle through the prediction model of the motor parameters. The best control scheme is gained by fuzzy reasoning to overcome the lag on the system making the adjustment process stable and realizing accurate predictive control. Thereby, the dynamic response of the system, anti-disturbance capability and control accuracy can be improved.

Abstract: Autoregressive moving average model (ARMA) was usually used for gyro random drift modeling. Because gyro random drift was a non-stationary, weak non-linear and time-variant random signal, model parameters were random and time-variant, too. For improving precision of gyro and reducing effects of random drift, this paper adopted two-stage recursive least squares method for ARMA parameter estimation. This method overcame the shortcomings of the conventional recursive extended least squares (RELS) algorithm. At the same time, the forgetting factor was introduced to adapt the model parameters change. The simulation experimental results showed that this method is effective.

Abstract: According to the development and current situation of DSP (Digital Signal Processing) at home and abroad, using high-speed computation ability and rich resources of TMS320F28335 chip to achieve higher real-time demand motion control in numerical control system (linear interpolation, continuous interpolation, position control, Serial communication, etc). On that basis, this paper discusses realization of hardware and software design method of this controller. Such movement controller has the perfect function and excellent performance, it often provides the multi-axis motion coordination control on the plate, and has higher control precision.

Abstract: A new type of logging transmit circuit applied to measurement while drilling (MWD) based on DDS technology is presented. As for logging instrument, Electromagnetic wave source is very important .The logging transmit circuit adopts TMS320VC33 series digital signal processing chip as main controller, in addition, LWD(logging while drilling) signal waveform generation circuit, peripheral signal processing circuit, DDS module, DSP and AD9850 interfaces, etc have been given.2MHz and 400KHz digital transmit circuit mainly composed of DDS AD9850 , which carries out the shift of the phase and the limit of the amplitude easily ,has been designed and debugged successfully. it is used to substitute for the conventional transmit circuit ，so the all-digital transmit channel of phase shift is achieved. The experimental results show that the logging transmit circuit for MWD is feasible.

Abstract: This article presents a real-time measurement method for the motion parameters of rocket nozzle by means of binocular vision and rocket nozzle rotation axes. With preprocessing, this method defines the rotation transformation relation between world coordinate system and fixed nozzle coordinate system by measuring the position of two nozzle rotation axes in world coordinate system based on binocular vision. During real-time measurement, the nozzle motion parameters can be measured with transformation of marker coordinate from world coordinate system to fixed nozzle coordinate system. This method overcomes the disadvantages of existing method, such as larger measurement error of motion parameters, more markers and single-dimension measurement. The experiment results verified this method and show that it can achieve higher measurement accuracy.

Abstract: For determine the location of the ingestible electronic pill inside the human body ，a new positioning system of the micro medical device inside the human body is designed. CC2430 communication chips combined with ZigBee protocol software are used as radio frequency transceiver of the system. When transmission power is very low, significant error codes will be generated at the receiving terminal. We can locate the electronic pill according to the analysis results of the packet error rate. And we adopt Trilateration to build up a set of nonlinear equations, which is related to the inter-node distance and spatial location variables of the pill. At last, equations are solved with numerical solution. It is found that the method is feasible.

Abstract: The paper presents a weighted tuning PI controller for speed estimating of induction motor using model reference adaptive system (MRAS) approach in a direct torque control system. The performance of speed controller affects the performance of sensorless each other. The objective of presented weighted tuning PI controller is to improve the performance of induction motor drive and enhance the performance of speed estimation. The presented controller is based on Ziegler-Nichols (Z-N) tuning formula with weighted tuning. The method improves the problem of parameter choice, reduces the over shoot and is simple as Z-N without system model. The availability of the proposed structure scheme is verified by through simulation results.

Abstract: Motor plays an important role in the dynamic property of the rotary-screw-driven dispensing system. Dynamic model of the motor was developed and validated in this paper. The output angle displacement and input voltage were measured from photoelectric digital encoder which is used to measure the angle displacement of the motor. In order to realize data smooth processing, Alpha-Beta filter was used. Discrete model of the motor was developed based on the Least Square Method and Model Selection criterion. Computational studies show that the system is equivalent to second order system. Moreover, the model was validated based on the experiment results under the different applied pressure and angular speed of motor. It is revealed that there is a good fit between experiment data and model simulation.

Abstract: Operation of neutron bandwidth limiting chopper requires high controlling precision. Phase difference between the chopper rotor and the synchronous pulse signal should be maintained to be fixed. Rotating frequency of the rotor needs to be very stable. To achieve the above technical requirements, control scheme, dynamic balance, and other means are made. Thus influences to control accuracy are effectively reduced, which are from rotor asymmetry and neutron absorbing materials. In the case described in this paper, phase tracking error was controlled under ±0.10752°with 90% confidence for the designed chopper.

Abstract: The designed electronic throttle control systems are able to diagnose faults, which affects the proper performance of the system. In this study, a fault-diagnosis algorithm of electronic throttle system based on parameter estimation is presented, using a simplified version of the DC motor model so as to minimize the relevant computation. By means of the Butterworth digital filtering state equation, the signal’s filtering value as well as its first-order and second-order derivatives are obtained. Thus, the operational precision is improved and the error influence from derivative discretization is avoided. The experimental results are consistent with the proposed algorithm employed in fault analysis.