Introduction. The article substantiates the necessity of determining the slippage of the tractor wheels during testing. The principle of operation and design of the sensors used to determine the slippage of the driving wheel in the testing of tractors and agricultural machines are considered; design features and characteristics of common shunting sensors based on a rotating disk with slots through a fixed angle are noted. The authors analized advantages and key disadvantages of existing sensors, such as the complexity of mounting and the need to manufacture the sensor mounting parts for a specific tractor model. The aim of the study is to develop a universal slip sensor for testing wheel and tracked tractors. Materials and Methods. The proposed solution determines the positions of the driving wheel in three-dimensional space on the basis of the inertial navigation system. The principles of operation of inertial navigation system components are described. The system consist of an accelerometer, a gyroscope and a magnetometer. The basic mathematical digital orientation filters applied for processing raw data are analyzed. Results. The design of the tractor slip determination device is developed. The main element of the mechanism is an inertial wheel position sensor. The selection of the main components of the sensor is substantiated: name and model of the inertial navigation system, the digital orientation filter and the microcontroller for the functioning the sensor. As a result of the research, the position sensor of the driving wheel was designed and manufactured on the basis of the MPU-9250 inertial navigation system and the STM32F405 microcontroller. The sensor software was developed in C language. A digital filter was based on the Madgwick algorithm for real-time data processing. Discussion and Conclusions. The result of the research was the development of a sensor for slipping the tractor wheels based on an inertial navigation system. This type of sensor is devoid of the main disadvantages of the widely used sensors of driving wheels. The advantages of the sensor are easy installation and method of wireless data transfer.

When testing agricultural machinery in order to determine its functional indicators, the ability to wirelessly transmit data between sensors, measuring and information systems are important. (Research purpose) To develop methods and create wireless digital devices for determining the functional indicators of agricultural tractors and machines with the ability to wirelessly transmit data to a remote control point in real time. (Materials and methods) The authors assumed that it was possible to determine the slipping of driving wheels using an inertial navigation system. It was found that in order to calculate real-time indicators obtained using wireless technologies, it was necessary to determine the characteristics of the input signals of discrete sensors on the side of the measuring system. (Results and discussions) The authors substantiated a method for determining the period of incoming signals of discrete sensors with an accuracy of 0.001 seconds for wireless information transmission. They proposed the design of a slipping sensor for an energy vehicle driving wheels, the main element of which is an inertial wheel position sensor. They developed a discrete signal input module and an inertial slipping sensor with the possibility of wireless data transmission based on a radio system with a carrier frequency of 433 megahertz. During field tests, it was found that the accuracy of determining slippage using the inertial wireless sensor IP-291 does not exceed 1 percent; the range of stable radio communication from the tested object to the test control center reaches 1000 meters; the current indicators obtained through digital radio communication did not differ from the indicators obtained in the tractor cab. (Conclusions) The authors worked out an effective system for wireless information transfer with the ability to calculate the performance of the tested equipment in real time.

Introduction. When carrying out an energy assessment of agricultural machines and traction tests of tractors, the most important indicator is the value of the tractive effort. The existing methods for determining the tractive effort of tractors imply the use of specialized measuring instruments, such as strain gauges and devices for processing and displaying information. The accuracy of determining the tractive effort is significantly influenced by the physical and mechanical properties of soil. To process the useful signal during the measurement of tractive effort, the data stream of the strain gauge sensor must be subjected to additional digital filtering taking into account the operating conditions of the agricultural unit. Materials and Methods. The functions of changing the tractive effort obtained on the K-744R2 tractor in various gears have been analyzed. An algorithm for digital processing of the signal of a strain gauge force meter based on a median filter has been developed that makes it possible to increase the measurement accuracy. The advantage of the proposed method is the ability to cut off sharp short-term impulse noise and sharp fluctuations in the amplitude of the measured value. Results. A method for determining the amount of tractive effort using median signal processing has been proposed. A device for determining the tractive effort during testing of agricultural tractors and units has been developed. The choice of the main components of the device for determining the magnitude of the tractive effort has been substantiated. As a result of the research, a device for measuring and digital processing of the signal of a force meter based on a microcontroller and specialized software for processing initial data in real time was designed and manufactured. Discussion and Conclusion. The developed method makes it possible to exclude the negative effect of impulse noise arising in the process of measuring the tractive effort of the tractor. The proposed device for measuring the tractive effort of tractors is compatible at the level of the exchange protocol with existing devices, has a high speed of operation in real time, multi-channel operation.