Applied Mechanics and Materials Vols. 433-435

Abstract: Vertical Sieve-tray Tower (VST) and grinding system are the key equipment of cement production line. The production of VST and grinding system involves complex physical and chemical mechanisms, harsh operating environment, fuzzy changing boundary conditions. It shows a multi-field coupling integrated complex multiphase. Yield, quality, efficiency, safety, energy conservation, emission reduction and other operational indicators of the system is not only interrelated but also mutual restraint. The physical relationship between system operation and system control performance indicator is not clear, so it is difficult to adopt traditional control methods based on mechanism modeling and model-based analysis. In view of that, a design of process-optimization expert control system is proposed for VST and grinding system. The system model is designed according to energy consumption and operating experience. It has optimal control of the entire procession for equipment operation and achieves minimum energy consumption to meet the production requirements.

Abstract: In order to achieve the function for automatic test paper and automatic scoring of blank-filling test module in the theory examination system for tower cranes, first of all, the blank-filling is classified based on the answer complexity of blank-filling, and the questions of blank-filling related table structure are designed. Then, test paper is automatically generated by extracting the corresponding questions based on the different random numbers generated random function rand (). Scoring is automatically accomplished by using the matching mode technology which compares the examinee answer and standard answer. Finally, the score is cumulated to calculated achievement for blank-filling test module by extracting the examinee score of the relevant information table. Therefore, the implementation of automatic test paper and automatic scoring can ensure the effectiveness of the test papers and the accuracy of the papers marked.

Abstract: The large airspace varying trajectory is modified to large airspace spiral maneuver trajectory, in order to improve the penetration effect of a supersonic anti-warship missile against enemy long-distance ship-to-air missile (LDSAM). In the descent phase the missile may suffer the interception of LDSAM, so the descent phase is modified to spiral maneuver descent trajectory. A variable structure guidance law is designed firstly. On the basis of it, a variable structure guidance law with spiral maneuver is proposed, in order to realize the large airspace spiral maneuver trajectory. The simulation results show that the proposed guidance law can guide the supersonic anti-warship missile to realize the large airspace spiral maneuver trajectory. The entire missiles performance indexes satisfy the flight requirement.

Abstract: Direct-drive volume control electro-hydraulic servo control system, derivation model of single-rod hydraulic cylinder system, pointed out that when the reciprocating motion characteristics are inconsistent. In order to solve this problem, proposed direct-drive differential volume control electro-hydraulic servo system design of its control system and analysis of system models. Through theoretical analysis, validate this proposed direct-drive bad dynamic volume control system, symmetric dynamic performance, improving control system reliability.

Abstract: Islanding detection techniques for DGPV are employed in order to determine the status of the electrical grid. In fact, the grid-connected inverter must be stopped once the islanding operating mode is detected according to standards and grid-code limits. Passive anti-islanding techniques monitor grid parameters to detect islanding. One advantage of passive techniques is a lower THD injected into the grid by active techniques. Thus, passive techniques were studied and an improved passive detection technique was proposed in this paper. The ratio of phase variation and the voltage variation at the point of common coupling (PCC) was adopted to detect islanding. In addition, this method combined with the under/over voltage detection and the under/over frequency detection. Then, the proposed technique not only has the merit of low cost and easy to operate, but also has multiple judgment and high reliability. The simulation results under Matlab/Simulink show that the proposed technique is very effective in reducing the non-detection zone and that the islanding operation can be detected more rapidly and effectively than traditional passive techniques, and that it can not misjudge when the load reduce suddenly.

Abstract: The inverted pendulum system is a high order, strong coupling, multi-variable and absolutely unstable nonlinear system. Its optimal control has been the hotspot in the field of study. A new two degree of freedom model driven PID control system is introduced in this paper.It will state the structure of the control technology and design steps.The control technology is applied to control linear inverted pendulum in this paper. The simulation results prove that two degree of freedom model driven PID control system has the feasibility and superiority.

Abstract: In order to evaluate security risks of long span bridge structure more scientifically and accurately. According to the principles of scientific, integrity, this paper applies grey-fuzzy theory to divide the security risk factors of long span bridge structure into quality cable, tower concrete foundations, weld cracks, expansion joints, and bridge deck pavement condition five types. First, according to the evaluation rules, use expert scoring method to score the individual evaluation index of long span bridge structure, fraction is in 0~100.Analyze the expert scoring by using grey theory, substitute the score into albino function, calculate grey statistics, and form weight matrix. This method can be used for comprehensive evaluation of security risks assessment of long span bridge structure.

Abstract: In order to intercept high maneuvering target, a super twisting guidance law based on extended state observer (ESO) is proposed. The target acceleration can be defined as external disturbance which can be estimated in ESO and compensated in super twisting guidance law. The super twisting algorithm can effectively decrease the undesired charting which exists in normal sliding mode control. The simulation results which are verified via computer show that this guidance law has strong robustness, target acceleration can be estimated and compensated, and has good miss distance.

Abstract: In this paper, we propose a Model Predictive Controller (MPC) based on Gaussian process for nonlinear systems with uncertain delays and external Gaussian disturbances. We investigate the ability of Gaussian process based MPC on handling the variable delay that follows a Gaussian distribution through a properly selected observation horizon. To test the effectiveness of this approach, comparisons are made for the proposed Gaussian process based MPC and RBF (Radial Basis Function) neural networks by analyzing the time complexity and control performance. In simulations, two experiments are designed to verify the results of different systems, including a first-order nonlinear plant and a second-order nonlinear plant with variable delays and Gaussian noises. It is demonstrated that the proposed approach may achieve the desired results.

Abstract: The generalized Wonham controllable canonical form in multi-input systems is presented and applied to pole placement of state derivative feedback. A new direct algorithm is proposed. The multi-input system can be decomposed some single-input systems and for every single-input system the problem is easy to be resolved. The advantage of this algorithm is no need to compute the characteristic polynomial of the system. The theory and approach are introduced, and the general expression containing arbitrary parameter is obtained for the derivative feedback gain matrix of the multi-input system. An illustrative example is presented to show the proposed method.