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US 2014/0156153 A1Published application
Real Time Pull-Slip Curve Modeling in Large Track-Type Tractors
AssigneeCaterpillar Inc.
InventorJoseph Faivre
Life of this patent
Estimating the term…
Abstract
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.
Claims20
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;
- and
- a 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;
- calculate a coefficient of traction (COT) from drawbar pull and slope at slip percentages in a first range;
- divide values of the nominal pull-slip curve by the COT to produce a normalized pull-slip curve;
- determine an optimum operating state using the COT and the slope;
- and
- provide the optimum operating state and a current operating point to a device for use in adjusting one or more current operating conditions.
9 more elements
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;
- and
- averaging 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;
- and
- using the adjusted pull-slip curve, the COT, and the slope to determine an optimum performance;
- and
- providing the optimum performance to a device for use in adjusting a current operating state of the track-type tractor to reach the optimum performance.
14 more elements
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%;
- and
- averaging 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;
- and
- using the adjusted pull-slip curve, the COT, and the slope to determine an optimum performance;
- and
- providing 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.
14 more elements
Dependencies are inferred from the claim text.