Experimental studies and identifying a model of the dynamic system “anti-vibration seat - operator” of a mobile machine

When creating new types of transport and technological mobile machines, it is important to ensure compliance with sanitary standards for vibrations at the driver’s seat. Anti-vibration seats are widely used to reduce vibrations transmitted from the engine and chassis of the machine to the operator's workplace. When designing a machine, mathematical modeling can be used to make a reasonable choice of seat parameters. Since the anti-vibration seat together with the operator’s body form a single dynamic system, the mathematical model must include both the anti-vibration seat and the operator’s body. The article presents an overview of mathematical models that describe vertical vibrations of the seated body. It describes an experimental setup for studying the dynamics of a human operator sitting in an anti-vibration seat. The experimental setup includes an electrodynamic vibration bench produced by LDS, control and recording equipment. The studies were carried out for the Sibeco anti-vibration seat. During testing, the base of the seat performed vertical harmonic vibrations with a gradually increasing frequency, while the amplitude of vibration accelerations was maintained constant. The accelerometers installed on the seat elements, on a special disk located on the seat cushion and on the operator’s body, recorded vibrations of these elements. As a result of processing experimental data, transfer functions were obtained. They connect the amplitudes of movement of various elements of the model with movements of the base in a given frequency range. The experiments were carried out with the participation of testers with different body weights. The article proposes a mathematical model that describes the vertical vibrations of the “vibration-protective seat - operator’s body” system. The inertial and elastic-damping characteristics of the seat elements were determined earlier during special tests. Based on a comparison of calculated and experimental data, the parameters of the model elements describing the operator’s body were refined. The parameters of the mathematical model obtained during the study will be used in the future research for calculation estimates of the vibration load of the operator’s workplace.