Design And Research Of Cleaning Device For Glass Greenhouse Roofs

Greenhouse is an important part of modern agriculture. In the recent decades, the greenhouses are extensively applied no matter at home or abroad. The increasing numbers of greenhouse meet the needs of people for high quality and quantity of products. However, because of fact that the greenhouse in a natural environment can easily be polluted by dust, microbes or other pollutant, the further applications of greenhouse are constrained. In general, the pollutant always occurs on the roof and the pollutant severely decreases the light transmittance of greenhouse. Manual-cleaning is the favorited method of cleaning the roof but it faces some problems. For example, high cost, low efficiency and high risk. Greenhouse includs glass greenhouse and plastic greenhouse, due to the two greenhouse have different shape structure and construction materials, their cleaning equipments also have some differences. Access to domestic and international research status on cleaning equipment of greenhouse roof, a little of study for glass greenhouse. Importantly, the current research of cleaning is focused on the cases of greenhouse without shade nets. But in applications, more greenhouses employ the shade nets to prevent the blazing sun, especially in our country. In practice, these greenhouses are hard to clean and in current, there is no feasible cleaning machine or equipment.This paper presents a overall design of cleaning device which is expected to be applicable to clean the roof of glass greenhouse with shade nets. This device can be automatically controlled by a wireless remote control system.This study determine the cleaning method through a test and design reasonable overall structure of the cleaning device.The cleaning device is mainly composed of bracket, walking mechanism, cleaning mechanism and lifting mechanism. It is controlled by remote wireless controller. The control system includes a transmitting unit and a receiving execution unit. And both the two units use microcontroller’s SPI serial communication function. In detail, the electronic hardware includes walking motor control module, cleaning motor control module, motor current detection module, lift motor control module, current limit detection module, top part detection module, walking synchronous detection module, wireless remote control module, work alarm module and power supply module, the electronic hardware use PIC 16F1828 chip of Mircroship company for the transmitter unit CPU of remote control, PIC18F4580 chip for the receiving and execution unit CPU, MRF49XA chip for the wireless transceiver module, MC33186 for walking motor drive chip, VNH5200AS-E for the lifting motor drive chip. The software program includes wireless transmission main program, reception execution main program, greenhouse roofs end interrupt subroutine, lifting limit positions interrupt subroutine, cleaning subroutine, advancing subroutine and back subroutine. The test of cleaning device is carried out.. It applied orthogonal test to select the parameters of cleaning effect influence factor about positive pressure, walking speed, broom rotate speed and water volume, and verified the rationality and reliability of the system.The test result implies this cleaning device can achieve the expected design function. It is controlled by remote wireless controller to clean, forward, backward, adjust the speed and stop. The system can realize automatically stop when reaching the end of glass greenhouse roof; automatically adjust the lifting motor to control the pressure of disc brush and roof’s glass, which can ensure the cleaning effect, The system have the function of synchronous detection and correction, which makes the left and right sides of cleaning device do not deviate. In addition, the system can real-time alarm for working. The further test shows when the cleaning device work in the optimal combination of cleaning effect impact factor, the light transmittance can reach up to 80% after the cleaning. Compared with 20% to 35% transmittance before cleaning, the cleaning device has a perfect performance.