Dynamic properties of a motor grader seat with quasi-zero static characteristics

Abstract

During operation, transport and technological machines and equipment experience significant vibration effects from the working environment, which are transmitted to the human operator through the cab seat. The negative impact of dynamic influences and vibrations transmitted through the seat to the operator is noted in many works. The use of vibration protection systems for operator seats requires their simulation and study on mathematical models, which is an urgent task in the design of such systems. Vibration protection systems with the effect of quasi-zero stiffness are promising. To study vibration protection systems with quasi-zero stiffness, a complex simulation mathematical model of a motor grader was developed, the movements of which are of a spatial nature. The model includes subsystems of supporting elements of the base chassis, vibration-proof supports of the operator’s cabin, and, finally, the vibration-proof mechanism of the operator’s seat. The last subsystem makes it possible to study vibration protection mechanisms with a given size of the zone of quasi-zero stiffness in the static force characteristic. Using the developed complex simulation model, the system’s responses to step actions exerted on the elements of the running equipment of the base chassis of the motor grader were studied. The effects on one of the wheels of the front balance axle and one of the wheels of the rear balance bogie of the motor grader were investigated. Two static power characteristics of the vibration-protective seat system were considered, one of which had a section of quasi-zero stiffness, and the second did not. According to the results of the computational experiment, it was established that the vibration protection system with a quasi-zero stiffness section provides maximum seat accelerations that are ten times less than a vibration protection system without a quasi-zero stiffness section. This confirms the promise of using vibration protection systems with the effect of quasi-zero stiffness.