Optimization Design and Test of GNSS Flat Control System

Farmland leveling technology can improve quality of farmland irrigation and uniformity of soil minerals，so as to achieve purpose of saving water and increasing production.With establishment and improvement of Global Navigation Satellite System（GNSS），fine formation technology of farmland land based on GNSS has been widely applied.The current use of GNSS positioning data for elevation closed-loop control is likely to cause overshoot of flat ground.A GNSS-based precision leveling electromechanical control system was designed，and a time-controlled hysteresis control algorithm was proposed.By controlling power-on time of solenoid valve，leveling scraper lift could be accurately controlled to reduce overadjustment.Experimental results showed that vibration of flat shovel could be reduced by 15% at low speed and 23% at high speed.At the same time，abrupt transition of flat spade elevation was effectively reduced，which was reduced by 30% at low speed and 8% at high speed.No matter low speed operation or high speed operation，more than 90% points could be guaranteed within±2 cm after completion of operation to meet precision requirements of land leveling.