Embedded Intellingent Dynamic Balance Testing System and Its Digital Filter Designing

A lot of information needs processing in time in dynamic balance testing, but the current intelligent dynamic balance instruments and the controlling box of dynamic balance machines made up ofsinglemicrocontroller do not meet the request.A method isgioen that the DSP-Microcontroller will be useddiredtlyinthe system of the intelligent dynamic balance instrumentby using embedded design technique. A principal and subordinate control system compose of DSP and microcontroller. The Microcontroller the system as a principal controller and the DSP implements digital filtering and FFT in dynamic balanc by means of its fast operation. The system develoyed according tothe method can do more analysisin time areaand frequency area.     

Robust H control for vehicle seat suspension systems with stochastic disturbance

The paper proposes the design method of robust H controller of vehicle seat suspension system. The dynamic model of seat suspension is developed,and the parameters uncertainties (mass, stiffness, damping) and stochastic vibration are introduced into the model system. Based on stochastic differential theory and Lyapunov functional, a semi controller is designed, and the controller parameters are solved by linear matrix inequality (LMI) which guarantees H performance index. The simulation results in time domain and frequency domain show that the controller designed for parameter uncertainties and stochastic vibration can attenuate the vertical acceleration of suspension system and improve riding comfort of human.     

The Active DC Filter Based on Hysteresis Controller on the DC Side of HVDC

For Passive Active Hybrid filtering system on the DC side of HVDC system, the controller based on Hysteresis method is presented, and the corresponding control circuits are also designed in this paper. Simulation results show very fast dynamic response and excellent compensating performance by using the proposed controller and the designed circuits.     

A NEW APPROACH OF LOAD FREQUENCY DECENTRALIZED CONTROL-OPTIMIZATION OF WEIGHT MATRIX Q

As the optimization and coordination of weight matrix Q and feedback gain matrix K are taken into account, the dynamic performance of the decentralized controller designed by this method is as good as that of the optimal controller. This method can be used in the strong or weak coupled systems, and various controllers can be designed according to the demand. An example is given to prove the validity and advantage of this method.     

Dynamic optimization design of gear transmission system for wind turbine

The differential equation which governs the behavior of the gear transmission system of 1.5 MW wind turbine is established. The external excitation caused by wind speed fluctuation is discussed and the internal excitation due to time varying mesh stiffness and comprehensive error is also analyzed. The calculating formulations of the harmonic balance method of nonlinear dynamic equations are presented. Then, the multi objective dynamic optimization model is developed to minimize the value of vibration acceleration and the overall volume. The optimization of a practical example using mixed discrete combined programming is performed. The result shows that the proposed method of modeling and optimization design can effectively reduce the wind turbines gearbox vibration levels and weight.     

Dynamic scheduling method of vehicle air-conditioning assembly shop based on feedback control

By analyzing the inherent uncertainties, discrete uncertainties and external environmental uncertainties, a dual-feedback control strategy and the dynamic scheduling method are proposed to solve the dynamic scheduling problem of vehicle air-conditioning assembly shop under uncertainty. Considering the reentrant constraint, equipment capacity constraint, and time discrete constraint etc., the multi-objective scheduling model of vehicle air-conditioning assembly shop is set up,taken the earliness/tardiness, process time, production cost and quality loss as optimization objectives. According to the characteristic of the model, sectional chromosome encoding, crossover operator and mutation operator are designed to prevent the generation of illegal solutions and improve efficiency of the algorithm. An example is given to prove the feasibility and validity of the approach.     

Human simulated intelligent control for dynamic walking of biped robot

A human simulated intelligent control scheme based on sensory-motor schema for dynamic walking of biped robot is presented to solve the complex controller design.The dynamics model of a five-link planar biped is established. By imitating human walking movement and apprehending the posture change of the legs, the complex process of dynamic walking for biped robot is divided by four sequence phases. The multi-mode control law and the group of sensory-motor schema are designed based on the analysis of quality-quantity combination to the phase plane. Simulation results show that the proposed control strategy is effective to ensure continuous dynamic walking of biped robot and the control method is simple and easy to be realized.     

Binary phase only filter based watermarking combined with discrete wavelet transform

The binary phase only filter (BPOF) based digital image watermarking combined with a discrete wavelet transform (DWT) was proposed. Firstly, the DWT transform was applied to an image. Then, the discrete Fourier transform (DFT) was applied to the low frequency subband of the DWT transform. Next, the phase information of the DFT was binarized to obtain the BPOF, which would be taken as the watermark and embedded into the corresponding magnitude. Compared to applying the DFT transform to the whole image and embedding the BPOF watermark in the entire frequency range, or in the low frequency range, the watermark robustness in JPEG compression is improved significantly while maintaining the watermark imperceptibility and detection efficiency. This method may be used to demonstrate the authenticity and integrity of an image. The simulation experiments demonstrate the efficiency of this method.     

利用频域有限元法分析内嵌管式辐射地板频域热特性

分析内嵌管式辐射地板的频域热特性,便于进一步了解内嵌管式辐射地板的动态热特征,为辐射地板的系统和控制设计提供重要的参考依据。建立了内嵌管式辐射地板的频域有限元模型,同时采用ANSYS软件建立了内嵌管式辐射地板的时域传热模型,通过2个模型的对比说明了频域有限元模型的准确性。采用频域有限元模型计算并分析了内嵌管式辐射地板的频域热特性。结果表明,在低频区域,地板的频域热响应基本不随频率变化,其传热过程接近于稳态,而在高频区域,地板的频域热响应随频率的变化十分剧烈,地板传热呈现明显的动态特征。当房间内存在较多成分的高频热扰时,关于辐射地板的传热计算应采用动态计算方法。     

中山市日平均气温时间序列的周期性与混沌性分析

用广东省中山市1955-2017年日平均气温时间序列分析周期与混沌性质。结果表明,功率谱为363d左右的年周期变化,为周期吸引子;是太阳直射点在南北移动导致。在滤去频率范围为0~0.005/d的年周期变化信息以后,功率谱呈连续谱;最大Lyapunov指数是正的,关联维数为10.1,表明高频气温变化部分具有混沌性。     

DIGITAL POWER SYSTEM STABILIZER ( DPSS )

A digital power system stabilizer ( DPSS ) and its design method are presented in this paper. The mathematical model of a single machine infinite bus power system is obtained using off-line parameter identifications, and on the base of the identified model the control system is synthesized by generalized minimum variance control principles. Through feedback combination of several signals this control system has double functions of damping low frequency oscillation and automatic voltage regulating. In order to avoid static errors the very effective way is to combine discrete generalized minimum variance control with continuous integral control. Besides the proposed control strategy is very simple in structures and very easy to realize. Simulation results under several cases have shown the correctness and effectiveness of the proposed control strategy.     

Improvement and simulation on direct torque control system of permanent magnet synchronous motor

To solve the problems of large flux, torque ripple and inconstant inverter switching frequency in conventional direct torque control (DTC), a space vector modulation (SVM) technique is introduced to the conventional PMSM-DTC system and analyzed thoroughly based on the mathematical model. This novel control method which enjoys the advantages of VC and DTC has only one easy adjustable PI regulator and is easy to realize. The simulation verifies that this control system is capable of effectively improving the steady state performance and keeping the excellent dynamic performance of the PMSM-DTC system simultaneously and remain the switching frequency constant.     

Time Domain BEM for Wave Propagation Problems in Layered or Anisotropic Media and Its Application in Engineering

The dynamic response of an underground powerhouse under seismic waves is studied by time domain BEM for anisotropic media. The responses of displacements and stresses are evaluated. The effects of angle and frequency of incident waves and the degree of media anisotropy on dynamic response of the underground structure are analyzed in detail. Some important findings for engineering are obtained.     

A NEW REDUCED-ORDER PREDICTIVE SELF-TUNING CONTROL ALGORITHM

This paper presents a new self-tuning controller for pure time-lag controlled processes. The experimental results of digital simulation and real-time control on the high temperature diffuse furnaces prove that the algorithm suits the mimimum or non - minimum systems which have large time-lag, and it has distinguished characteristics in real-time and control precision.     

The compensation method for the random time-delay of the feedbackchannel and the forward channel in the networked control system

An improved predictive control method is presented to compensate the random time delay in the networked control system. The feedback time delay is compensated by predictive controller based on softened increment input strategy. The forward time delay is unknown for controller, so an extra feedback loop is added to compensate the delay by estimating the error between the actual control signal effected on plant and the output of controller in historical moment. For the controlled system with unknown or slowly varying parameters, the networked feedback correction algorithm is discussed based on a modified recursive least-squares identi cation algorithm. The system stability is analyzed and the simulation results show that the time delay in the networked control system can be accurately compensated. The excellent network performance is ensured with this strategy.     

The Application of Narrowband Interference Suppression in Direct Sequence Spread Spectrum

In order to improve the system effect, it is necessary take the technique of digital signal process to suppress interference, because of the finite gain and the narrow-band interference in system of direct sequence spread spectrum. The authors design a new filter structure improving on tunable digital heterodyne adaptive notch filters. This filter can adaptively track the interference frequency and control the bandwidth and depth of notch, which has the excellent agility and utility. The experiment proves this method overcomes limitation of other interference suppressions, hardly weaken the system performances, enhances the stability of the filter system, and can quickly track the interference frequency.     

THE MATRIX METHOD FOR ESTABLISHING DISCRETE SYSTEM DYNAMIC EQUATIONS

In this paper a matrix method for establishing discrete system dynamic equations is presented. Using this method to establish discrete system dynamic equations, netting but the derivative of function, and matrix multiplication are required. This method suits to the holonomic system as well as the linear nonholomic system.     

Fuzzy Comprehensive Evaluation on Landslides Risk Assessment Induced by Extreme Rainfall

The hazard assessment of the highway landslide induced by the extreme rainfall is a complicated systemetic issue.By combining the modified analytic hierarchy process and the fuzzy comprehensive evaluation,all the factors that influence the highway landslide are analyzed.And the comprehensive evaluation index system as well as the danger rating is established.In the process of evaluation,different rainfall's dynamic weighting system is fixed,and then the membership of continuous and discrete index are calculated respectively by using the trapezoid membership function formula and expertise assignment,and finally case study is carried out.It is shown that this method is suitable and rational to evaluate the highway landslide induced by extreme rainfall.     

Analysis of model-following control for multi-axle steering vehicle

The dynamic model of multi-axle steering vehicle is improved by considering the impact of the front-axle mechanical steering on the vehicle steering performance and implying the front-axle wheel angle in control variables to reduce the difficulty of vehicle control. On the basis of modified dynamic model, the multi-axle vehicle is analyzed by combining model-following method with pole assignment process. The transient response and frequency domain characteristics of the yaw angle velocity and sideslip angle at different speeds are obtained. The results indicate that, using model-following method to control vehicle can obtain desired tracking effects. At high speed, the transient response has no overshoot, the response time is shortened, and the stability of vehicle is improved.