Increasing accuracy of measuring functioning parameters of agricultural units

Abstract

The paper substantiates the ways of increasing the accuracy of measuring the parameters of agricultural units (AU) functioning. It has been noted that agricultural machines and units work in conditions of vibrations and noises created by the environment and technological tools. Features of the movement of these systems and their compliance with their functional purpose are factors that determine the degree of perfection of AU. The study of the dynamics of AU operation requires new research methods and means, therefore a measuring system of the dynamics and energy of mobile machines was created. Increasing the accuracy of measuring parameters of AU operation is achieved by substantiating the data processing algorithm of the sensors of the measuring system. The main component of the measurement system is an inertial measurement unit (IMU), which consists of an accelerometer, a gyroscope, and a magnetometer. It was established that the signal measured by IMU consists of four components: real acceleration; angles of inclination of the AU element relative to the horizon; vibration and inherent noise of the sensor. The IMU installed on the tractor frame determined that the main spectrum of oscillations is in the range from 0 to 3 Hz. The maximum vibration energy corresponds to a frequency of 0.4 Hz. The second harmonic of the oscillations is at a frequency of 25 Hz for the three axes of the accelerometer. An algorithm for data processing by the measuring system has been developed, including processing with the Butterworth filter, compensation of centrifugal velocities, tilt angles, free fall acceleration. The Butterworth low-pass filter with a cut-off frequency of 3 Hz was used to compensate for the real acceleration. The speed and position data of the GPS receiver included in the measuring system must be processed by the Butterworth frequency filter with a cut-off frequency of 1 Hz. It was determined that the maximum traction power of the tractor is 108.0 kW. It was established that the power determined by the measuring system due to acceleration and data processing by the developed method is 101.3 kW. The error of measuring the traction power of the tractor is 6.2%.