Device for detecting ferromagnetic bodies in the feed path of forage harvesting machinery based on the Hall sensor

Abstract

The operation principle of metal detectors used in forage harvesting equipment operating in the harvested area is based on the registration and processing of a signal from sensors that respond to changes in the static magnetic field caused by the movement of ferromagnetic bodies in the area of the magnetic field. The systems based on measuring coils do not meet modern requirements for the level of sensitivity. The authors consider a possibility of using magnetic field sensors based on the Hall effect as sensitive elements. Taking into account the geometric features of the system, each sensing element must be positioned in such a way that the magnetic field generated by two adjacent magnets is perpendicular to the plane of the sensing element. Under this design, the sensitive elements should be located in planes oriented at different angles relative to the direction of the crop supply. When a ferromagnetic object passes through the detection field, it changes the magnetic field density on one or more sensing elements, and the Hall effect sensor outputs a voltage directly proportional to the magnitude of the magnetic field. This signal is processed, after which another signal is generated to stop the feed rolls. Efficient real-time signal processing has a positive effect on the speed of response to a foreign body in the machine feeder.