This Is AuburnElectronic Theses and Dissertations

An Automatic Depth Control System for the On-the-Go Soil Strength Sensor




Smith, Clifford

Type of Degree



Electrical and Computer Engineering


Hardpans are areas of soil compaction formed by vehicle traffic or natural processes. These compacted areas beneath the topsoil can hinder successful crop production. A novel sensor for measuring soil strength was presented in an earlier work, and patented as the OSSS (On-The-Fly Soil Strength Sensor). The focus of this thesis is the design and evaluation of a control system for this new method of sensing soil strength. The graphical user interface has been implemented with National Instrument’s LabVIEW R software, and drives an analog PID-type (proportional, integral, and derivative) position controller for a hydraulic cylinder. This controller causes the strength sensor to vertically oscillate in the soil at consistently spaced distance intervals, regardless of tractor speed variations. Successful development enables this system to collect soil strength information over an entire field at all desired depths in a short period of time.