Applied Mechanics and Materials Vol. 392

Abstract: In this paper, the explicit constrained min-max MPC problem is solved by an algorithm which is based on a discrete-time linear system with uncertain disturbances. Since the maximum of the quadratic cost function is only attained at extreme point of the disturbance set, the designed method is proposed in two different kinds of active extreme point sets, which correspond to two kinds of state regions. As a result, the state space is partitioned into polyhedral regions and a piecewise linear feedback control law has been defined over resulting cones.

Abstract: This paper proposes a decentralized control law of NlCyP&BG for a team of autonomous agents, which aims at achieving collective and uniform distribution around an appointed destination. A technique by virtual of coordinate constraints is described for eigenvalues derivation and contribution analysis, so that conditions for local asymptotical stability of n-agent system is deduced. Simulation work on a two-agent case and an extended four-agent case are displayed to prove the validity of stability conclusion, and at the same time the effectiveness of control law in accomplishing expected distribution and reorientation is verified exactly.

Abstract: It is difficult to model and solve the reliability of complicated dynamic system in the traditional reliability modeling method. A new reliability modeling method based on generalized stochastic petri net (GSPN) is proposed to analyze the wireless control system (WCS). After studying the common faults of the WCS, a dynamic fault tree is constructed to analyze the system, and it is transformed into formalization definition of GSPN. Finally, a certain type of WCS is selected to validate the proposed method. This method has important value to other WCS design and analysis.

Abstract: Data acquisition is one of the processes to obtain the signal information. This paper designed a data collection system which is based on ARM Cortex-A8 processor for traditional crane, to acquire position signals and alarm signals. The results will be transmitted through RS232 serial communication bus to the receiver, then be displayed, so the field signals will be real-time monitored, the operations to the crane will be safe.

Abstract: The electron beam welding has high energy density, and the advantages of small welding deformation, in the defense, automotive, shipbuilding, precision machinery and other industries has been widely applied. Traditional electron beam welding machine power supply system adopts the technology of the power frequency or medium frequency, high volume, low efficiency and poor stability of electron beam. Combining with the characteristics of electron beam welding power source and the existing shortcomings, I put forward a digital filament power control scheme based on STM32, and introduce the hardware and software implementation method in detail. Experiments show that it can realize soft-start and soft-down process, and also be quickly identified and promptly forbid the output when filament fracture, which realize the intellectualization of filament power supply.

Abstract: This article develops the automatic test system of voltage and current dynamic waveform for circuit breaker. The system has the automatic monitoring, the storage and the display function of contact voltage and current waveform of circuit breaker in switching process. And then, it also designs the hardware and software of voltage and current dynamic monitoring system for miniature circuit breaker: the hardware circuit of this test system mainly consists of the detection circuit and the data acquisition circuit of current and voltage. And the software system, which mainly consists of control program, data acquisition program and data processing program, is programmed under the condition of LabVIEW. At last, it carries on the real-time monitor to the voltage and current waveform at the both ends of the circuit breaker, especially for the waveform during the switching process, which contributes to study the arc energy and contact wear of circuit breaker.

Abstract: This paper proposes a new improved zero-voltage switching isolated boost converter with coupling inductors. With the traditional advantages of smaller input current ripple, low diode voltage rating, and low transformer turns ratio of boost half bridge topology [ being retained, the proposed converter makes it much easier to realize zero voltage switching of primary switches compared with conventional converters.

Abstract: With the three-dimensional field analysis software Ansoft, we establish three-dimensional finite element model of the electromagnetic release, obtain the electromagnetic release static characteristics of electromagnetic force by simulation, and analyze the relationship between the electromagnetic force, the short-circuit current and the air gap size. By Analyzing the dynamic characteristics of moving iron core, different short-circuit currents influence on the velocity and displacement of the moving iron core was gained.

Abstract: Under low air pressure, dc arcs often levitate from surface of polluted insulator to form air-gap arcs during flashover process. The U-I characteristic of surface arc is different from that of air-gap arc. Considering the characteristic differences between surface arc and air-gap arc, the values of characteristic indexes indicating the effects of pollution and air pressure on flashover voltage are studied theoretically. The theoretical values of the characteristic indexes are also compared with reported experimental data.

Abstract: This paper introduces the working principle of the research of simulation in the main circuit of Static Var Generator based on Cascade H-Bride and takes the three-phase Static Var Generator based on cascade H-Bride with rated capacity 10kVar,rated voltage 380V for example to proceed the MATLAB simulation. The research shows that the more amount of cascade H-Bride, the more number of output voltage levels in the main circuit of Static Var Generator, the smaller value of voltage waveform distortion factor, and the less harmonic content be inject in electric network, which improves power index.