Abstract: In the agricultural freshwater breeding, the appropriate amount of water grass is conducive to fish respiration and can purify water quality, but the excessive amount of water grass will affect the survival and growth of fish. Mechanical mowing is the most widely used mowing method at present. The propulsion system of mowing boat was an important link of mechanical mowing. Brushless DC motor was a typical mechatronic equipment. Using the embedded technology, power electronics technology, analog electronics technology and digital electronics technology, the control system of the mowing boat based on brushless dc motor was designd, and realized the direction control, speed control and mowing control of navigation through hardware design and software design were realized. Through the prototype test, the control system has higher practicability and stability. Compared with the traditional brush DC motors, the mechanical mower with brushless DC motor has a longer life.

Key words: mechanical mowing, freshwater farming, brushless DC motor, navigation control