Model of a dynamic system of an industrial tractor for researching the vibration load of the driver-operator workplace

When designing self-propelled road construction equipment, it is important to ensure compliance with sanitary standards at the driver-operator's workplace. At the same time, mathematical modeling of the machine's dynamics is widely used to justify the selection of vibration isolation characteristics for the workplace. The problem of reducing vibration loading is especially relevant for bulldozers based on crawler tractors with semi-rigid suspension. The article presents a mathematical model describing the dynamics of the “tracked bogie - body - cabin - vibration-protective seat with driver” system of a crawler tractor with semi-rigid suspension. The model describes low-frequency vibrations caused by the movement of support rollers on a link track. The proposed model is distinguished by a detailed description of the track drive, which allows us to study the influence of soil properties, the arrangement of support rollers, the shape of the supporting surface of the tracks, etc. on machine vibrations. When modeling the dynamics of the vibration-protective seat with the operator, a multi-mass model is used, which allows us to study the vibration loading of various parts of the driver - operator's body. Differential equations of motion of the system are given. To obtain the spectral density functions of vertical vibration accelerations at the driver's seat, a spectral method is used. A technique for obtaining the spectral density functions of vertical and angular displacements of the tracked bogie is considered. Techniques for obtaining frequency transfer functions linking the generalized coordinates of the mathematical model with the input effect and calculating the mean square values of vibration accelerations in standard frequency bands are also presented. The results presented in the article confirm the need to use a multi-mass vibration-protective seat with a driver-operator to obtain an adequate assessment of the vibration loading of the workplace. The developed model and calculation methodology will be used in the future to solve a number of practical problems.