Applied Mechanics and Materials Vols. 541-542

Abstract: The Hydro-mechanical variable transmission (HMT) is an infinitely variable and high efficient multi-power flow transmission, whose stepless speed ratio changing process includes speed ratio changing in range and power shift. In this paper, a HMT control strategy is proposed that includes four components: speed control strategy in range, power shift condition, power shift logics and power shift control strategies. The simulation results of the two-range HMT demonstrate that the proposed control strategy can stabilize the engine speed to the target operating area near the optimal speed and can satisfy demands of the vehicle acceleration, slide and brake.

Abstract: Simulation research work is presented for fuel cell supercapacitor hybrid powertrain. Sub-systems of the fuel cell hybrid powertrain are modeled, simulation system is developed and load following control strategy is designed. Vehicle dynamic and fuel economy performance are investigated through simulation method and the control strategy is verified through experiments on dynamic testbed. Simulation and test result show that supercapacitor can work well for power assist and fuel economy performance is improved through brake energy recovery.

Abstract: One of the disadvantages of traditional direct torque control is high torque ripple, A method of reduce torque ripple was proposed basing bus-clamping and duty ratio control technique in this paper. Firstly, the switch vector table with bus-clamping technology was improved by analyzing the role of zero voltage vector to reduce torque ripple in different sector of voltage. Secondly, on the base of combing the improved bus-clamping direct torque control (BCDTC) and discrete duty ratio control (DDRC), a new switch vector table with discrete duty ratio and bus clamping was designed by analyzing the role of zero voltage vector to reduce torque ripple in different speed range. Finally, simulations are performed to verify the proposed strategies.

Abstract: Foaming machine is a piece of important equipment in the production process of the foam concrete. This paper designed the control system with singlechip as the core of the digital processing. The communication between the singlechip and frequency converter was realized through RS485 port and the automatic control of the working process of the air compression double-bubble foaming machine can come true. The high performance-cost ratio of the single ratio enables the system control to be economical and practical; the touchscreen interface makes it simple to use; and the multi-gear setting also is easy to adjust and control. All these improve the overall performance of the foaming machine.

Abstract: Taking into consideration the lack of control precision of the hydraulic system of intelligent asphalt disperser, an internal model control method based on BP neural network was proposed. In this method, the ability of identification of complicated systems using neural network was combined with the feature that internal model control has low requirements on the model precision. In this way, the design of hydraulic controller of asphalt disperser can be achieved. The results show that this method has better robustness with regard to the systematic uncertainty and disturbance when compared with the PID control system, and the control effect is better, which provides a novel approach for the control of hydraulic system of intelligent asphalt disperser.

Abstract: In fermentation process, substrate concentration control is important in increasing product concentration, productivity and substrate yield so as to decrease the production cost. But, the feedback control of substrate concentration is difficult for the lack of sensor for online measurement of substrate concentration. In order to overcome above problem, dissolved oxygen (DO) stat strategy was developed for feedback control of glucose feeding in fedbatch fermentation using the abrupt increase of DO as the indicator for glucose depletion and glucose feeding. In this research, the DO stat control strategy for bioreactor control will be developed and the control process will be simulated. The simulation results indicate that the DO stat strategy is effective in glucose feeding control.

Abstract: This paper reports the simulation and experimental results of a type of widely used load control valve. The investigated load control valve is usually applied to the mobile crane booming hydraulic circuit. It is used to balance the overrunning load due to gravity and to modulate the flow of oil when lowering the load. The load control valve has a significant influence on the performance of mobile crane booming system. A simulation model of the load control valve is established based on AMESim, moreover, a bench-test is conducted to evaluate the performance of the load control valve. The simulation results and the experiment data agree well and both results show a good performance of the valve. Further study of the effect and the inner principle of the key design parameters of the load control valve are also presented.

Abstract: PLC control system in heavy lift improved the lift performance. It became more intelligent, simple operation and running . The design uses frequency converters as executive agencies to design a system to control 3-layer lift, so as to realize the normal operation of its various works.

Abstract: Using the bounded sigmoid function and two-order Butterworth low-pass filter, a self-controlling feedback method for regulate the motion of a chaotic system is presented in this paper. It is shown that such controller has the advantage of being easy to implement based on the measurable input signals. A rigorous stability proof is provided from LaSalle Invariance theorem. Furthermore, the effectiveness and efficiency of the proposed feedback control strategy is illustrated by means of the numerical simulations of two-well Duffing Vander Pol oscillator. Finally, the result reveals that the enough large maximum amplitude results in a more possible regular domain in parameter space of the controlled oscillator.

Abstract: In order to improve the dependability and security of the lever control system, we introduced the generalized predictive control (GPC) algorithm. We used MATLAB/Simulink program development tools to control the double capacity water tank. At first, we used the water tank level control device as the object and set up a mathematical model of the control system. Then we put forward the generalized predictive control algorithm based on the model. The simulation results show that the presented algorithm has a good dynamic response performance, fast-track settings, and a preferable control effect. Experimental results show that the improved methods are reasonable and practicable.