Assessment and Improvement of the Low-Frequency Vibrational Comfort on Agricultural Machinery by Optimized Cabin Suspension

摘要

This work aims at the improvement of the low-frequency vibrational comfo rt on mobile agricultural machines. Assessment of the comfort situation on a combine harvester shows that the European action and limit values f or low-frequency vibrational comfort are violated for several working co nditions of the machine. The frequently used rubber cabin mounts have a deteriorating effect on the comfort of the operator in the low-frequency region. Two alternative cabin mounts are designed consisting of hydraulic and pn eumatic components. Non-linear parametric models based on first principl es are derived and verified experimentally. Optimization of the model pa rameters is performed with respect to the objective comfort values effec tive root means square and vibration dose value. Alternatively the devia tion for an ideal frequency response function is also proposed as goal t o be minimized. A six degree of freedom linear model of the cab suspension is derived. B y incorporating linearized models of the cab mounts, predictions can be made of the resulting comfort values for the different working condition s. These predictions are verified by evaluation of the physical cabin su spension system on a hydraulic test rig. In-situ measured vibration sign als are reproduced by the rig enabling the evaluation of the suspension under controlled lab conditions.