Hou You-fu

A Fuzzy PID Cascade Control System of a Hydro-viscous Drive Speed Regulating Start

The effect of hydro-viscous drive speed regulating start depends both on reasonable structural design and appropriate control strategy. But the control system used at present cannot completely satisfy practical requirements. In order to resolve the problem, a fuzzy PID cascade control system is presented based on cascade control theory in this paper. In auxiliary control loop a PID controller is used to adjust the proportional relief valve, in main control loop a fuzzy PID controller is used to control the system. The fuzzy PID cascade control system was simulated by using Matlab software. The results show that the system can meet the actual demands quite well. To verify correctness of theoretical analysis, a test-bed of hydro-viscous drive speed regulating start was built and the experiments were carried out. The results prove the feasibility of the fuzzy PID cascade control system. Different from the simulation, in experiments, the output speed lags behind the given speed to a large extent because of the static friction force of the system. It is inevitable. More attention should be paid to this case in design of the control system.

Distinct Element Method Simulation of Discharging in Coal Silos

Particulate discharging for a coal silo is simulated by using distinct element method. In this paper, the mobility of coal particles in the silo and varieties of individual particles displacement and velocity in the flow are observed. Both static pressure and dynamic pressure are measured, and also the changes of pressure on the plane of the hopper. All of the above show the flow characteristics of coal particles.

An ontology-based information integration technology for technique preparation

In order to realize information integration and information sharing of technique preparation process, idea of ontology was applied in technique preparation process. The concept of technique preparation domain ontology was proposed and its formalization definition was presented. Moreover, the structure of technique preparation domain ontology was designed and the information integration framework for technique preparation based on domain ontology was put forward. Finally, an application case was illustrated and the information integration framework was proved efficient.