Distance measurement device and vehicle velocity control device for maintaining inter-vehicular distance
First Claim
1. A distance measurement device comprising:
- distance measurement means for measuring a distance to an object and outputting measurement values periodically;
a weighting means operable to adjust each of said measurement values by weighting each of said measurement values with at least one of previously measured value and previously adjusted measurement value to obtain a currently adjusted distance value; and
selecting means for selecting a weighing constant of said weighting means, from a plurality of weighting constants, depending upon a current measurement value output from said distance measurement means;
wherein said weighing means uses said selected weighting constant to adjust the currently measured value to thereby provide said currently adjusted distance value.
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Abstract
The computer (CPU) of a distance measurement device determines the inter-vehicular distance by applying a software filter (weighing means) upon successive values obtained directly from measurement. A vehicle velocity control device for maintaining the inter-vehicular distance include a distance measurement device for measuring the inter-vehicular distance, and the deviation ΔR of the inter-vehicular distance with respect to the target inter-vehicle distance RS is determined. The vehicle velocity is controlled on the basis of the deviation ΔR in accordance with the PID (proportion plus integral plus differential) control method, and the gains are varied in accordance with the current value of the inter-vehicular distance.
70 Citations
19 Claims
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1. A distance measurement device comprising:
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distance measurement means for measuring a distance to an object and outputting measurement values periodically; a weighting means operable to adjust each of said measurement values by weighting each of said measurement values with at least one of previously measured value and previously adjusted measurement value to obtain a currently adjusted distance value; and selecting means for selecting a weighing constant of said weighting means, from a plurality of weighting constants, depending upon a current measurement value output from said distance measurement means; wherein said weighing means uses said selected weighting constant to adjust the currently measured value to thereby provide said currently adjusted distance value. - View Dependent Claims (2, 3, 4)
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5. A vehicle velocity control device for maintaining an inter-vehicular distance comprising:
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distance measurement means mounted on a vehicle for measuring a distance to another vehicle and outputting measurement values periodically; weighting means operable to adjust each of said measurement values by weighting each of said measurement values with at least one of previously measured value and previously adjusted measurement value to obtain a currently adjusted distance value; selected means for selecting a weighting constant of said weighting means from a plurality of weighting constants depending upon a current measurement value output from said distance measurement means; wherein said weighting means uses said selected weighting constant to adjust the currently measured value to thereby provide said currently adjusted distance value; and vehicle velocity control means, coupled to said weighting means, for controlling a vehicle velocity of said vehicle on the basis of said currently adjusted distance value supplied from said weighting means, such that said distance to said another vehicle is maintained at a target inter-vehicle distance.
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6. A vehicle velocity control device for maintaining an inter-vehicular distance, comprising:
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distance measurement means mounted on a vehicle for measuring a distance to another vehicle and outputting measurement values at a predetermined sampling period; a weighting means operable to adjust each of said measurement values by weighting each of said measurement values and a previously adjusted measurement value to obtain a currently adjusted distance value; selecting means for selecting a weighting constant of said weighting means from a plurality of weighting constants depending upon a current measurement value output from said distance measurement means; wherein said weighting means uses said selected weighting constant to adjust the currently measured value to thereby provide said currently adjusted distance value; deviation detection means, coupled to said distance measurement means, for calculating a deviation of said currently adjusted distance value from a target inter-vehicle distance; calculation means, coupled to said deviation detection means, for calculating a parameter corresponding to said deviation; and vehicle velocity control means, coupled to said calculation means, for controlling a vehicle velocity of said vehicle on the basis of said parameter, such that said distance to said another vehicle is maintained at said target inter-vehicle distance. - View Dependent Claims (7, 9, 10, 11, 12, 13, 14)
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8. A vehicle velocity control device as claimed in claim 8, wherein:
said calculation means decreases at least one of said proportional gain and said differential gain when said current measurement value output from said distance measurement means increases, and increases at least one of said proportional gain and said differential gain when said current measurement value output from said distance measurement means decreases.
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15. A vehicle velocity control device for maintaining an inter-vehicular distance, comprising:
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distance measurement means mounted on a vehicle for measuring a distance to another vehicle and outputting measurement values at a predetermined sampling period; calculation means, coupled to said distance measurement means, for calculating a differential of said measurement values with respect to time; weighting means operable to weight successive values of said differential of said measurement values with respect to time, said weighting means calculating a weighted average of a plurality of said successive values of said differential, wherein a weight assigned to a current value of said differential in taking said weighted average of a plurality of said successive values of said differential is inversely proportional to a weighting constant; and vehicle velocity control means, coupled to said distance measurement means and said weighting means, for controlling a vehicle velocity of said vehicle on the basis of said measurement values in accordance with proportional plus integral plus differential control, such that said distance to said another vehicle is maintained at said target inter-vehicle distance;
wherein a differential control value of said proportional plus intergral plus differential control is obtained by multiplying an output of said weighting means by a differential gain. - View Dependent Claims (16, 17, 18, 19)
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Specification