Temperature Control System Design And Experiments Of Asphalt Pavement Recycling Equipment Heated By Microwave

The energy of microwave heating comes from the internal electromagnetic field changes of dielectric material. During the course the energy is absorbed and converted into heat when electromagnetic wave enters from the surface into the medium and transmits in its internal,as well it will not reduce either in-depth dielectric or on surface. Microwave heating recycling technique of asphalt pavement is based on the principle. The temperature gradient of its heating is small,besides heating distributes is homogeneous and the process is highly efficient.Conventional temperature control methods by microwave heating are PID control, two degree freedom PID control, fuzzy control. Theoretical models is related to electromagnetic fields and heat transfer control equation.Because all the properties of asphalt mixture vary with temperature it is unrealistic to determine the relationship between them, therefore we only select the main parameter to study while the remaining parameters are assumed to be constant.By the simplifying model, temperature control system transfer function is established, and then by using fuzzy PID control the parameters are simulated online.It is the first time that fuzzy-PID control has been used in asphalt paver heated by microwave.In the " microwave heating equipment in asphalt pavement recycling and its temperature control experiment ", it respectively set the irradiation angle declination of microwave heating magnetron for 0°, 15°, 20°, 30°, limits the heating time in 5min, 10min, 15min, 20min, controls heating height for 5 cm, 10cm, 15cm, 20 cm and selects measuring depth for 0 cm, 5 cm, 9cm, 15 cm. It tests the impact of these parameters to temperature and fit certain function curves. And it compares with the data without fuzzy-PID controller. Finally, recycling maintenance technique of asphalt pavement of microwave heating is prospected.