초록 ▼

A method of estimating soil conditions of a work surface during operation of a track-type tractor measures current operating conditions and current operating state to develop adjustments to a nominal pull-slip curve. The adjusted pull-slip curve is used to calculate optimum performance in terms of a

A method of estimating soil conditions of a work surface during operation of a track-type tractor measures current operating conditions and current operating state to develop adjustments to a nominal pull-slip curve. The adjusted pull-slip curve is used to calculate optimum performance in terms of an input variable such as track speed. Two factors are developed to reflect soil conditions, coefficient of traction and a shear modulus adjustment that affect different portions of the nominal pull slip curve.

대표청구항 ▼

1. A track-type tractor adapted to characterize soil conditions during operation, the track-type tractor comprising: a slope sensor that provides a slope of the track-type tractor;a track speed sensor that provides a track speed of the track-type tractor;a processor coupled to the slope sensor and t

1. A track-type tractor adapted to characterize soil conditions during operation, the track-type tractor comprising: a slope sensor that provides a slope of the track-type tractor;a track speed sensor that provides a track speed of the track-type tractor;a processor coupled to the slope sensor and the track speed sensor; anda memory coupled to the processor, the memory storing a plurality of modules that when executed by the processor, cause the processor to: access a nominal pull-slip curve stored in the memory;store data received from the slope sensor and the track speed sensor;collect a plurality of samples of drawbar pull over a period of time;calculate an instantaneous pull-weight ratio as a function of drawbar pull, rolling resistance, and slope for each of the plurality of samples of drawbar pull to generate a plurality of pull-weight ratios;calculate a coefficient of traction(COT) from the plurality of instantaneous pull-weight ratios;divide values of the nominal pull-slip curve by the COT to produce a normalized pull-slip curve;determine an optimum operating state defined as the highest possible value of cycle power of the track-type tractor using the calculated COT, the normalized pull-slip curve, and the slope; andprovide the optimum operating state and a current operating point to a device for use in adjusting one or more operational settings of affecting the operating state of the track-type tractor. 2. The track-type tractor of claim 1, wherein the plurality of modules cause the processor to calculate the coefficient of traction by calculating the plurality of instantaneous pull-weight ratios (PWratio) as (Drawbar Pull−Rolling Resistance)/(machine mass*gravity*cos θpitch). 3. The track-type tractor of claim 2, wherein the plurality of modules cause the processor to: retain only instantaneous pull-weight ratios that meet all of:data is taken while in a forward gear;a track slip is greater than 20%;no steering activity;no brake activity;deceleration pedal not activated; andeach of the instantaneous pull-weight ratios must be in a range of a minimum of about 0.5 to a maximum of about 1.2. 4. The track-type tractor of claim 3, wherein the plurality of modules cause the processor to: perform a validation test to determine that the plurality of instantaneous pull-weight ratios meet a data population criteria and a convergence criteria. 5. The track-type tractor of claim 4, wherein the plurality of modules cause the processor to: offset the COT by a multiple of a standard deviation to account for a population bias at a low end of a slip range. 6. The track-type tractor of claim 1, wherein the plurality of modules further cause the processor to: develop a shear modulus adjustment factor to characterize soil conditions from pull-weight ratios observed at a slip percentage in a second range that partially overlies the first range. 7. The track-type tractor of claim 6, wherein the second range is about 0.5% to about 40%. 8. The track-type tractor of claim 6, wherein the plurality of modules cause the processor to: calculate the shear modulus adjustment factor using a plurality of normalized pull-weight ratios (rpw) as rpw=PWratioCOT and to retain from the plurality only those values that meet additional criteria including at least one of:data is taken while in a forward gear;the track speed is in a range of a minimum of about 50 mm/s to a maximum of about 1500 mm/s;track acceleration is less than approximately 50 mm/s2;rpw is less than approximately 0.99;a COT value must have been successfully developed;ground speed must be available;no steering activity;no brake activity;deceleration pedal not activated. 9. A method of characterizing soil conditions during operation of a track-type tractor, the method comprising: providing a nominal pull-slip curve corresponding to a standard soil condition;receiving, at a processor, data from at least one sensor of the track-type tractor, the data corresponding to a slope of the track-type tractor and one or more of a track speed, a ground speed, and a drawbar pull;producing, at the processor, a coefficient of traction (COT), wherein producing the COT includes: calculating a plurality of instantaneous pull-weight ratio values using the drawbar pull and the slope;removing instantaneous pull-weight ratio values from the plurality of instantaneous pull-weight ratio values that fail to meet a first screening criteria; andaveraging the instantaneous pull-weight ratio values that meet the first screening criteria to produce the COT;normalizing, at the processor, the nominal pull-slip curve by the COT to produce a normalized pull-slip curve;producing, at the processor, a shear modulus adjustment factor that characterizes soil conditions, wherein producing the shear modulus adjustment factor includes: calculating a plurality of normalized pull-weight ratio values;removing normalized pull-weight ratio values that fail to meet a second screening criteria;calculating the shear modulus adjustment factor from the normalized pull-weight ratio values meeting the second screening criteria;applying the shear modulus adjustment factor to the normalized pull-slip curve to obtain an adjusted pull-slip curve; andusing the adjusted pull-slip curve, the COT, and the slope to determine an optimum performance; andproviding the optimum performance to a device for use in adjusting a current operating state of the track-type tractor to reach the optimum performance. 10. The method of claim 9, further comprising performing a validation test on each of the plurality of instantaneous pull-weight ratio values that meet the first screening criteria to determine that the plurality of instantaneous pull-weight ratio values meet a data population criteria and a convergence criteria. 11. The method of claim 9, wherein removing instantaneous pull-weight ratio values that fail to meet the first screening criteria comprises removing the instantaneous pull-weight ratio values that fail any of: data is taken while in a forward gear;a track slip is greater than 20%;no steering activity;no brake activity;deceleration pedal not activated;must be in a range of a minimum of about 0.5 to a maximum of about 1.2. 12. The method of claim 11, further comprising offsetting the COT by a multiple of a standard deviation to account for a population bias at a low end of a range of track slip. 13. The method of claim 9, wherein normalizing the nominal pull-slip curve by the COT comprises dividing each point on the nominal pull-slip curve by the COT. 14. The method of claim 9, wherein calculating each of the plurality of normalized pull-weight ratio values (rpw) comprises calculating rpw=PWratioCOT. 15. The method of claim 9, wherein removing normalized pull-weight ratio (rpw) values that fail to meet the second screening criteria comprises removing the normalized pull weight ratio values that fail any of: data is taken while in a forward gear;track acceleration is less than approximately 50 mm/s2;track slip is in a track slip range of a minimum of about 0.5% to a maximum of about 40%;a COT value must have been successfully developed;the ground speed must be available;no steering activity;no brake activity;deceleration pedal not activated. 16. The method of claim 15, wherein calculating the shear modulus adjustment factor (kadj) comprises fitting an estimated slip (s′) to a measured slip (s) based on the inverse function of the normalized pull-slip curve over the normalized pull-weight ratio values meeting the second screening criteria using a data fitting technique. 17. The method of claim 16, wherein determining the estimated slip of the tracks at any normalized pull weight ratio (rpw) comprises performing a calculation of (f−1 (rpw))*kadj), where f−1 is the inverse function of the normalized pull-slip curve. 18. A method of characterizing soil conditions during operation of a track-type tractor implemented by execution of computer-executable instructions stored on a computer readable memory storing computer-executable instructions, the method comprising: providing a nominal pull-slip curve corresponding to a standard soil condition;receiving, at a processor, data from at least one sensor of the track-type tractor, the data corresponding to a slope of the track-type tractor and one or more of a track velocity, a ground speed, and a drawbar pull;producing, at the processor, a coefficient of traction (COT), wherein producing the COT includes: calculating a plurality of instantaneous pull-weight ratios using the drawbar pull and the slope;removing from the plurality of instantaneous pull-weight ratios the instantaneous pull-weight ratios that fail to meet a first screening criteria, the first screening criteria including removing the instantaneous pull-weight ratios corresponding to a slip value less than 20%; andaveraging the instantaneous pull-weight ratios that meet the first screening criteria to produce the COT;normalizing, at the processor, the nominal pull-slip curve by the COT to produce a normalized pull-slip curve;producing, at the processor, a shear modulus adjustment factor, wherein producing the shear modulus adjustment factor includes: calculating a plurality of normalized pull-weight ratio values;removing normalized pull-weight ratio values that fail to meet a second screening criteria, the second screening criteria including removing the normalized pull-weight ratio values corresponding to a slip outside a range of about 0.5% to about 40%;calculating the shear modulus adjustment factor from the normalized pull-weight ratio values meeting the second screening criteria;applying the shear modulus adjustment factor to the normalized pull-slip curve to obtain an adjusted pull-slip curve; andusing the adjusted pull-slip curve, the COT, and the slope to determine an optimum performance; andproviding the optimum performance to a device for use in adjusting an operating state of the track-type tractor to achieve a performance closer to the optimum performance. 19. The method of claim 18, further comprising: collecting a minimum of about 300 pull-weight ratio values that meet the first screening criteria to produce the COT;collecting a minimum of about 800 of the normalized pull-weight ratio values that meet the second screening criteria to produce the shear modulus adjustment factor. 20. The method of claim 19, further comprising: collecting additional normalized pull-weight ratio values;producing two additional shear modulus adjustment factors; and averaging the three shear modulus adjustment factors to produce a final shear modulus adjustment factor used in further calculations.