Abstract: A precision calibration method of attitude measuring systems is provided. The precision calibration method of attitude measuring systems includes the following steps: calibrating a zero-deviation, a scale coefficient, and a non-orthogonal angle between axes of an accelerometer to the attitude measuring system via an ellipsoid fitting model (S1); compensating original data of the accelerometer using a calculated ellipsoid parameter (S2); calibrating an electronic compass via the ellipsoid fitting model according to compensated accelerometer data (S3); compensating original electronic compass data by the calculated ellipsoid parameter (S4); calculating an attitude according to the compensated data of the accelerometer and compensated data of the electronic compass (S5). The above steps of the method have a reliable calibration result and a high precision with a less time consumption of calibration.

Abstract: Disclosed is a hydraulic control valve assembly of automatic steering system for agricultural machine including a proportional directional valve (3). A balancing valve (1) is arranged between the proportional directional valve (3) and the steering cylinder. A first shuttle valve (2) is arranged between the proportional directional valve (3) and the balancing valve (1). The first shuttle valve (2) is positioned on one side of the proportional directional valve (3). An overflow valve (4) is positioned on another side of the proportional directional valve (3). The overflow valve (4) is connected to a second shuttle valve (6) and a logic valve (5) respectively. The hydraulic control valve assembly has a large control power, a rapid response, and is more suitable for the autonomous navigation operation of agricultural machine. Moreover, the system saves more energy, such that the autonomous navigation operation of agricultural machine is more stable.

Abstract: A precision calibration method of attitude measuring systems is provided. The precision calibration method of attitude measuring systems includes the following steps: calibrating a zero-deviation, a scale coefficient, and a non-orthogonal angle between axes of an accelerometer to the attitude measuring system via an ellipsoid fitting model (S1); compensating original data of the accelerometer using a calculated ellipsoid parameter (S2); calibrating an electronic compass via the ellipsoid fitting model according to compensated accelerometer data (S3); compensating original electronic compass data by the calculated ellipsoid parameter (S4); calculating an attitude according to the compensated data of the accelerometer and compensated data of the electronic compass (S5). The above steps of the method have a reliable calibration result and a high precision with a less time consumption of calibration.

Abstract: Disclosed is a hydraulic control valve assembly of automatic steering system for agricultural machine including a proportional directional valve (3). A balancing valve (1) is arranged between the proportional directional valve (3) and the steering cylinder. A first shuttle valve (2) is arranged between the proportional directional valve (3) and the balancing valve (1). The first shuttle valve (2) is positioned on one side of the proportional directional valve (3). An overflow valve (4) is positioned on another side of the proportional directional valve (3). The overflow valve (4) is connected to a second shuttle valve (6) and a logic valve (5) respectively. The hydraulic control valve assembly has a large control power, a rapid response, and is more suitable for the autonomous navigation operation of agricultural machine. Moreover, the system saves more energy, such that the autonomous navigation operation of agricultural machine is more stable.

Abstract: A method of updating an all-attitude angle of an agricultural machine based on a nine-axis MEMS sensor includes the following steps: establishing an error model of a gyroscope, an electronic compass calibration ellipse model and a seven-dimensional EKF filtering model, and setting a parameter vector corresponding to a vehicle motional attitude (S1); acquiring data including an acceleration and an angular velocity of a motion of vehicle, and an geomagnetic field intensity in real time (S2); calculating an angle, a velocity, position information, and a course angle of the vehicle by established error model of the gyroscope and the electronic compass calibration ellipse model(S3); data-fusion processing the angle, the velocity, the position information and the course angle of the vehicle by the seven-dimensional EKF filtering model, and updating a motional attitude angle of the vehicle in real time. The steps of the method have a small error, high precision, and reliability.