Abstract: To solve the problem that the demand of plant growth lighting environment is nonlinear, time-varying and difficult to establish accurate mathematical model, this paper proposes a novel control system based on fuzzy control algorithm and fuzzy language description to realize the high precision control of plant growth lighting environment. In this system, PC interface based on LabVIEW, is used to set photon flux density (PFD) values of red, blue, green wavelength bands light for different plants or the same plant on different growth stages. In the lower computer system, 3 TEMT6000 light intensity sensors are used to detect the real-time PFD of red, blue and green bands and output the reasoning and decision-making according to voltage difference signal of red, blue, green light, then control quantity of LED light source module is achieved and PWM values are dynamically adjusted, thus intensity output of LED light in red, blue, green bands is controlled and PFD values of the plant lighting required for red, blue, green bands are ensured. Simulation and experiments show that the system realizes the intelligent adjustment to control red, blue, green light intensity output accurately and stablely, which meets the needs of plant growth lighting environment.

Key words: fuzzy control, PWM, light environment