Measurement and Analysis of Mechanical Vibrations Caused by Corn Head Clutch Slippage

摘要

Slippage of a corn head row unit is an event that occurs when one or more row units become clogged with foreign materials and a clutch coupling the drive shaft to the row unit is subjected to slipping. The slippage can cause severe mechanical damage to the system and yield loss as the row unit ceases to operate. Since it is difficult for the operator to observe the slip event during harvesting, the development of a system for detecting a slip event is essential to protecting the mechanical integrity of the head. One very possible indication of the event is the mechanical vibration generated by each row unit of the corn head. In order to develop a vibration based monitoring system, preliminary data was collected during normal operation and during slip events to characterize the slip event. A field-programmable gate array (FPGA) based data acquisition system and accelerometers were employed to collect high-frequency vibration data. The sensors were mounted at key locations on individual row units and the endplate of a corn head to determine the most robust location to identify a slip event. The gathered data was transformed using FFT (Fast Fourier transform) to frequency domain, which is information-rich for characterizing vibration signals. Data assessment was conducted using the raw and the FFT-transformed data. The outcome includes the quantification of sensor response in both time and frequency domain and the quantification of variability in the responses. The resulting responses to slip events provided maximized mounting locations to detect an event. Model Based Software Development has been utilized to develop a monitoring algorithm that provides a Boolean response to a slip event on a corn head.