| Popis: |
A variable depth control peanut digger was developed as an automated system to control the three point hitch top link position on a 2-row KMC peanut digger, aimed at reducing peanut digging losses across a variety of soil textures. Investigation was performed to determine if top link position, and therefore the digger blade angle, can be prescribed as a function of soil electrical conductivity (EC) prescription maps, relating to soil texture, or on-the-go sensor-based feedback control. Sensors included for evaluation of on-the-go depth control included: (1) load cells fixed to ripper shanks for direct measurement of soil draft force; (2) a pressure transducer mounted to a hydraulic top link for measurement of digger reactant force; and (3) a rotary potentiometer mounted to a depth gauge for indication of blade depth. A linear potentiometer was included to indicate extension of the hydraulic top link. The measures of soil draft force were included to evaluate on-the-go indication of soil texture, because proper digger top link adjustment has been indicated to be dependent on soil texture. The hydraulic top link position was adjusted using a computer-operated directional control valve. EC mapping was used to divide a field into three texture zones, with each soil texture zone divided into 12 m (40 ft) long 2-row plots. Soil texture measurement, as indicated by hydrometer testing, demonstrated a good relationship with soil EC. On-the-go data from the front soil draft force sensing shank, top link pressure transducer, and blade depth gauge all correlated with digger setting, increasing in value with decreasing top link extension, with the top link pressure transducer statistically showing the most promise for use as a feedback-based control sensor. The results indicated that soil EC maps coupled with on-the-go sensor-based adjustment is feasible for prescription of variable depth digger settings. |
