Transient characteristics analysis of linear flux-switching permanent magnet machines for precision control

A dynamical dq model is proposed for a linear flux-switching permanent magnet（LFSPM） machine which is suitable for high-precision control applications.The operation principle of the prototype machine is analyzed using the finite element method（FEM）,and the parameters,such as the back electromotive force（EMF） and the phase flux linkage,are calculated.The calculated and measured results reveal that the back EMF and the flux linkage are essentially sinusoidal,and the variation of the phase flux linkage profile of the LFSPM machine is similar to that of the linear surface permanent magnet（LSPM） machine.Based on this,a dynamical dq model and a simulation control model are proposed.The simulation results are compared with the test results obtained from a DSP-based control platform,which verifies that the model is correct and effective.Moreover,the model can be used for design optimization and control development.

Method of Precision Control of 3-D Solid Discretization Based on the Second-Order Osculating Surface

A discretization precision control method based on the second order osculating surface is proposed. The discretization precision of 3 D solid is controlled according to the error between the discrete solid surface and its second order osculating surface. The global maximal error has been gotten after analyzing all the extremums of the error function. It can be used in controlling and optimizing the discretization precision of 3 D solid in computer 3 D modeling and NC milling path generation.

Study on the methods of precision controlling for the manufacture of hull curvature sections

The precision controlling technology is a key step for the modern ship construction, with the precision controlling of the ship-hull curvature as one of bottlenecks in shipbuilding, where the initial is to present a compensation value for the ship-hull plate precisely. The compensation value of the curvature plate is composed of two parts: the construction compensation, which results in the process of heating construction of curvature plate, and the assembling compensation, which results in welding ribbed stiffeners onto the curvature plate. Based on the developed computation system for the local contraction value, this paper presents a method to establish the experimented samples for the assembling compensation by means of numerical experiments, and another method to establish the practical mathematical model for the construction compensation of curvature plate. Furthermore, it introduces the experimental measuring method for the assembling compensation of the curvature plate, based on which the related database system has been developed. Numerical examples are analyzed to demonstrate the process to establish mathematical model for the assembling compensation values.

Neural network solution for finite-horizon H-infinity constrained optimal control of nonlinear systems

In this paper, neural networks are used to approximately solve the finite-horizon constrained input H-infinity state feedback control problem. The method is based on solving a related Hamilton-Jacobi-Isaacs equation of the corresponding finite-horizon zero-sum game. The game value function is approximated by a neural network with time- varying weights. It is shown that the neural network approximation converges uniformly to the game-value function and the resulting almost optimal constrained feedback controller provides closed-loop stability and bounded L2 gain. The result is an almost optimal H-infinity feedback controller with time-varying coefficients that is solved a priori off-line. The effectiveness of the method is shown on the Rotational/Translational Actuator benchmark nonlinear control problem.

Design methodology of a mini-missile considering flight performance and guidance precision

The design of mini-missiles(MMs)presents several novel challenges.The stringent mission requirement to reach a target with a certain precision imposes a high guidance precision.The miniaturization of the size of MMs makes the design of the guidance,navigation,and control(GNC)have a larger-thanbefore impact on the main-body design(shape,motor,and layout design)and its design objective,i.e.,flight performance.Pursuing a trade-off between flight performance and guidance precision,all the relevant interactions have to be accounted for in the design of the main body and the GNC system.Herein,a multi-objective and multidisciplinary design optimization(MDO)is proposed.Disciplines pertinent to motor,aerodynamics,layout,trajectory,flight dynamics,control,and guidance are included in the proposed MDO framework.The optimization problem seeks to maximize the range and minimize the guidance error.The problem is solved by using the nondominated sorting genetic algorithm II.An optimum design that balances a longer range with a smaller guidance error is obtained.Finally,lessons learned about the design of the MM and insights into the trade-off between flight performance and guidance precision are given by comparing the optimum design to a design provided by the traditional approach.

Clustered Wireless Sensor Network in Precision Agriculture via Graph Theory

Food security and sustainable development is making a mandatory move in the entire human race.The attainment of this goal requires man to strive for a highly advanced state in thefield of agriculture so that he can produce crops with a minimum amount of water and fertilizer.Even though our agricultural methodol-ogies have undergone a series of metamorphoses in the process of a present smart-agricultural system,a long way is ahead to attain a system that is precise and accurate for the optimum yield and profitability.Towards such a futuristic method of cultivation,this paper proposes a novel method for monitoring the efficientflow of a small quantity of water through the conventional irrigation system in cultiva-tion using Clustered Wireless Sensor Networks(CWSN).The performance measure is simulated the creation of edge-fixed geodetic clusters using Mat lab’s Cup-carbon tool in order to evaluate the suggested irrigation process model’s performance.Thefindings of blocks 1 and 2 are assessed.Each signal takes just a little amount of energy to communicate,according to the performance.It is feasible to save energy while maintaining uninterrupted communication between nodes and cluster chiefs.However,the need for proper placement of a dynamic control station in WSN still exists for maintaining connectivity and for improving the lifetime fault tolerance of WSN.Based on the minimum edgefixed geodetic sets of the connected graph,this paper offers an innovative method for optimizing the placement of control stations.The edge-fixed geodetic cluster makes the network fast,efficient and reliable.Moreover,it also solves routing and congestion problems.

Application of Monte Carlo method in rudder control precision

After the trajectory simulation model of rudder control rocket with six degrees of freedom is established by Matlab/ Simulink, the simulated targeting of rudder control rocket with rudder angle error and starting control moment error is carried out respectively by means of Monte Carlo method and the distribution of impact points of rudder control rocket is counted from all the successful subsamples. In the case of adding interference errors associated with rudder angle error and starting time error, the simulation analysis of impact point dispersion is done and its lateral and longitudinal correction abilities at different targeting angles are simulated to identify the effects of these factors on characteristics and control precision of the rudder control rocket, which provides the relevant reference for high-precision design of rudder control system.

Development of a PWM Precision Spraying Controller for Unmanned Aerial Vehicles

This paper presents a new Pulse Width Modulation (PWM) controller for Unmanned Aerial Vehicle (UAV) precisionsprayer for agriculture using a TL494 fixed-frequency pulse width modulator together with a data acquisition board and developedsoftware. An UAV can be remotely controlled or flown autonomously by pre-programmed flight plans. The PWMcontroller was implemented through the guidance system on the UAV with control commands sent between the UAV helicopterand the ground control station via a wireless telemetry system. The PWM controller was tested and validated using LabVIEW8.2. Several analyses were performed in a laboratory to test different control signals. The results show that the PWM controllerhas promise as a higher precision technique for spray applications, which will improve efficiency of pesticide application,especially in crop production areas.

Stability of networked control systems with multi-step delay based on time-division algorithm

A new control mode is proposed for a networked control system whose network-induced delay is longer than a sampling period. A time-division algorithm is presented to implement the control and for the mathematical modeling of such networked control system. The infinite horizon controller is designed, which renders the networked control system mean square exponentially stable.Simulation results show the validity of the proposed theory.

Synchronization Control of the Oppositely Driven System with Dual Asymmetric Cylinders

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The Research on Adaptive Control Modeling of a Liquid Fertilizer Spreader

This paper describes a general modeling and control approach for steering wheel variable rate liquid fertilizer applicator. An adaptive numerical modeling approach for describing the system input-output dynamics is proposed, and an optimal control that accounts for the control hardware limits is developed. Field tests have demonstrated the effectiveness of the theoretical development.

H∞ Output Feedback Control of Constrained Systems via Moving Horizon Strategy

这份报纸与致动器浸透为分离时间的系统处理 H 产量反馈控制问题。开始，一条抑制 H 输出反馈控制途径在线性矩阵不平等(LMI ) 的框架被介绍优化。在骚乱精力界限上的某些假设下面，靠近环的 H 性能被完成。而且，动人的地平线策略被用于控制性能的一个联机管理以便靠近环的系统能在意外大骚乱的情况中满足控制限制。驱散限制被导出完成动人的地平线靠近环的系统消散。模拟结果证明抑制 H 控制器在骚乱假设下面有效地工作并且动人的地平线 H 控制器罐头交易自动地在令人满意的控制限制和提高的性能之间。

Active vibration control of spindle in ultra-precision turning machine

In order to minimize vibration and improve rotary precision of spindle, we apply active vibration control technique to ultra-precision turning machine based on the analysis of vibration characteristic of aerostatic bearing spindle. Using aerostatic bearing itself as actuator, the vibration of spindle is controlled by adjusting admission pressure respectively and by changing pressure distribution in the bearing. The experiments and simulations prove that this method can minimize the vibration of spindle effectively.

Analysis on the Impacts of Precise Poverty Alleviation on Folk Customs and Control Measures

The promotion of precise poverty alleviation in poverty-stricken areas will inevitably lead to changes in local folk customs.The economic development may bring about greater development of folk customs,and may also lead to qualitative changes in folk customs.This paper mainly introduced the impact of the precise poverty alleviation on the folk customs.Based on the analysis,it came up with pertinent control measures,to better combine the folk customs with precise poverty alleviation measures,to promote common development of economy and culture in poverty stricken areas.

An Electro-Mechanical Controller for Adjusting Piston Pump Stroke On-the-Go for Site-Specific Application of Crop Nutrients

Nutrient application systems are designed to apply a relatively uniform amount of a fertilizer to agricultural fields. However, considerable variation in soil texture and other characteristics often occurs within and across production fields, which could have a major impact on fertilizer management strategies. Therefore, uniform application of a fertilizer over the entire field can be both costly and environmentally unsound. Due to their rugged and fool-proof design, crankshaft type piston pumps are widely used in agriculture. The on-the-go outlet flow of these pumps can only be varied by changing the drive shaft speed for each pump stroke setting. But only a limited range of flow rates can be achieved by changing the drive shaft speed. There is a need for an electronic controller, which can adjust the pump stroke on-the-go, for real-time, variable-rate application of crop nutrients. The Clemson “Electro-me-chanical controller for adjusting pump stroke on-the-go” was designed to replace the current manual stroke adjustment system on positive displacement piston pumps. This affordable system can be retrofitted on most John Blue - piston pumps for real-time adjustment of the pump stroke and can be controlled using pre-described position sequences (map-based) or real-time sensor commands (such as optical, pressure, and flow sensors) combined with fertilizer calculation algorithms. In addition, it can adjust pump stroke manually, using an eclectic dial from the tractor’s cab.

Evaluation of the Effects of High-efficiency Compound Formulations on the Prevention and Control of Sugarcane Brown Rust

[Objectives]This study was conducted to screen high-efficiency compound formulations and precise application technologies for the prevention and control of sugarcane brown rust. [Methods] Zineb, dinconazole, mancozeb, azoxystrobin, pyraclostrobin, difenoconazole·azoxystrobin, chlorothalonil and carbendazim were selected for field efficacy tests. [Results] Four formulations,(65% zineb WP 1 500 g+75% chlorothalonil WP 1 500 g+potassium dihydrogen phosphate 2 400 g+agricultural synergist 300 ml)/hm^(2),(12.5% dinconazole WP 1 500 g +75% chlorothalonil WP 1 500 g+potassium dihydrogen phosphate 2 400 g+agricultural synergist 300 ml)/hm^(2),(80% mancozeb WP 1 500 g+75% chlorothalonil WP 1 500 g+potassium dihydrogen phosphate 2 400 g+agricultural synergist 300 ml)/hm^(2) and(30% difenoconazole·azoxystrobin SC 900 ml+potassium dihydrogen phosphate 2 400 g+agricultural synergist 300 ml) had good control efficacy on sugarcane brown rust, and showed disease indexes all below 18.79 and control efficacy over 80.53%. The four formulations are ideal high-efficiency compound formulations for the prevention and control of sugarcane brown rust. They can be sprayed manually and by unmanned aerial vehicles on the foliar surface from July to August, once every 7 to 10 d, continuously for 2 times. [Conclusions] This study provides new technical support for accurate and efficient prevention and control of sugarcane rust.

Evaluation of the Effect of High-efficiency Compound Formulations on the Prevention and Control of Sugarcane Brown Stripe

[Objectives]This study was conducted to screen high-efficiency compound formulations and precise application technologies for the prevention and control of sugarcane brown stripe disease.[Methods]Carbendazim,benomyl,chlorothalonil,azoxystrobin,pyraclostrobine and difenoconazole·azoxystrobin were selected for field efficacy tests.[Results]Three formulations,(50%carbendazim WP 1500 g+75%chlorothalonil WP 1500 g+potassium dihydrogen phosphate 2400 g+agricultural synergist 300 ml)/hm^(2),(50%benomyl WP 1500 g+75%chlorothalonil WP 1500 g+potassium dihydrogen phosphate 2400 g+agricultural synergist 300 ml)/hm^(2) and(25%pyraclostrobin 600 ml+potassium dihydrogen phosphate 2400 g+agricultural synergist 300 ml)/hm^(2) had good control effects on sugarcane brown stripe disease,and showed disease index below 14.02 and control efficacy above 84.41%.The three formulations are ideal high-efficiency compound formulations for the prevention and control of sugarcane brown stripe disease.They can be sprayed manually and by unmanned aerial vehicles on the foliar surface from July to August,once every 7 to 10 d,continuously for 2 times.[Conclusions]This study provides new technical support for accurate and efficient prevention and control of sugarcane brown stripe disease.

Study on Model Predictive Control to Minimize Movements in Positions Due to Thermal Expansion of Plate with Varying Generation of Heat

Precise temperature control to decrease movements in positions due to thermal expansion of work pieces is required in the manufacturing processes to achieve nanometer-order accuracy. We analytically examined the effect of a method of minimizing movements in positions on a plate with varying generation of noise-heat. Control by monitoring temperature changes caused larger movements in positions than that without control because maximum change in temperature occurred at non-monitoring positions. The best method of minimizing movements in positions due to thermal expansion of a plate with varying generation of noise-heat was model predictive control by the monitoring movements and distributed temperature changes in the control heater according to the effects of the generation of noise-heat. The maximum movement in positions was 6 nm, which was 1/4 times of that without control.

Practical stabilization of receding-horizon control

The purpose of this work is to propose a scheme to stabilize the predictive control systems in the practical stability sense. In the paper, the authors dealt with a general discrete predictive control system x j+1|t =f(x j|t , u j|t ) by using the Lyapunov direct method combining with receding horizon control technique, and presented a new condition to guarantee the practical stabilization of the systems. With the proposed results, one can design the optimal controllers easily to practically stabilize the predictive control systems.

INTELLIGENT PRECISION CONTROL IN CNC GRINDING

The development of intelligent control techniques provides powerful means for the control of machine tools. In this paper, a intelligent control technique and an algorithm for precision control of CNC grinding of ceramic chips are introduced. In the process of ceramic chip CNC grinding, the dimension of the chips tends to get larger and the dimensional error to exceed the tolerance as the number of the chips increases which are machined on the same part program. There are many factors leading to the occurrence of the error and the law of error variation is very complicated. With the introduced intelligent self learning error compensation technique, the CNC system can improve the control strategy to compensate the error automatically. The simulational result is also given.