The Design And Development Of Control System For Expressway Tunnel Ventilation

The cleanliness of air condition in tunnel have important effect to the safety ofpeople who go through this tunnel.In order to ensure the cleanliness of the tunnel air,making the CO concentration inside the tunnel and VI value is always within the rangeof reasonable,it’s necessary to design the ventilation system in tunnel.Althoughconventional control strategy can meet this requirement, lots of electric energy is wastedbecause too many fans tuned on.So, finding a reasonable control strategy to optimize thenumber of fans to be opened has an important and realistic significance on reducing theenergy consumption of ventilation systems.In order to achieve this goal, this paperconducted the following studies:(1) First, one-dimensional mechanical analysis on tunnel ventilation is conducted.Second,many aerodynamics models are build up to describe different parts of theventilation system, and the coupling relationship between these models is expounded.Atlast, the equation of the pollutants transportation and its’ solution method is proposed,which lay the foundation for the simulation of control effects.(2) The importance of the forecast of traffic flow for the tunnel ventilation system isemphasize in this paper.Many kinds of forecast method on traffic flow, including theiradvantages or disadvantage, are listed.What’s else, an ARMA-GARCH model is built upand used to predict the short time traffic flow, and the precision meet the demands ofengineering application.(3) In order to overcome the Large-lag and nonlinear problem of the ventilationcontrol systems, a feed forward fuzzy control strategy is put forward, and its’ availabilityis also analysised.Under the guidance of the control strategy, such a fuzzy controller isdesigned that its’ the input variables are the predicted traffic flow data and the bias ofCO density between the set-point and the actual value.At last, a simulation is conductedon the control effects of this control strategy in contrast to another control strategy-“fengduan control” by the Matlab software, which vividly proved the effectiveness ofthis control strategy, and it made the predictive control comes true.(4) A hardware platform on tunnel ventilation control is set up, the function and typeof each part of the platform is also introduced, and a upper computer software isdeveloped based on the visual basic computer language.What’s more, the controlalgorithm is integrated into the upper computer software which resulting from the Matlab software.Finally, this paper provided the thoughts of programming for PLC, and theauthor debugged the soft and hardware system successfully in the end.