Vehicle rotational-angle calculating apparatus

• US 5,644,082 A
• Filed: 06/29/1995
• Issued: 07/01/1997
• Est. Priority Date: 06/30/1994
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Iwata, Eiji, Maeda, Hiroyuki
• Primary Examiner(s): O'Shea, Sandra L.
• Assistant Examiner(s): Noori, Max H.
• Application Number:
  US08/496,618
• Time in Patent Office: 733 Days
• Field of Search: 73/503.3, 73/504.01, 73/504.02, 73/504.03, 73/504.18, 73/118.1
• US Class Current: 73/504.03
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments

Abstract

A first sensor outputs a signal representing an angular rate of a vehicle body. A second sensor outputs a signal representing a direction of the vehicle body. The output signal of the first sensor is integrated to generate a signal representing a tentative rotational angle of the vehicle body. First data pieces are generated which represent temporally spaced samples of the output signal of the second sensor respectively. Second data pieces are generated which represent temporally spaced samples of the tentative rotational angle signal respectively. Two first data pieces are selected from among the first data pieces. Calculation is given of a time interval between the occurrence moments of the selected two first data pieces. Two second data pieces are selected from among the second data pieces. Calculation is given of a direction difference between directions represented by the selected two first data pieces. Calculation is given of a rotational-angle difference between tentative rotational angles represented by the selected two second data pieces. An amount of offset in the output signal of the first sensor is calculated in response to the calculated time interval and the calculated rotational-angle difference in cases where the calculated direction difference is equal to or smaller than a predetermined direction difference. The output signal of the first sensor is corrected into an offset-free signal in response to the calculated offset amount. The offset-free signal is integrated to generate a signal representing a final rotational angle of the vehicle body.

Claims

1. A vehicle rotational-angle calculating apparatus comprising:

a first sensor outputting a signal representing an angular rate of a vehicle body;

a second sensor outputting a signal representing a direction of the vehicle body;

first means connected to the first sensor for integrating the output signal of the first sensor to generate a signal representing a tentative rotational angle of the vehicle body;

second means connected to the second sensor for generating first data pieces representing temporally spaced samples of the output signal of the second sensor respectively;

third means connected to the first means for generating second data pieces representing temporally spaced samples of the signal generated by the first means respectively;

fourth means connected to the second means for selecting two first data pieces from among the first data pieces generated by the second means, the selected two first data pieces relating to occurrence moments spaced by at least a given time;

fifth means connected to the fourth means for calculating a time interval between the occurrence moments of the selected two first data pieces;

sixth means connected to the third means for selecting two second data pieces from among the second data pieces generated by the third means, the selected two second data pieces relating to occurrence moments corresponding to the occurrence moments of the selected first data pieces respectively;

seventh means connected to the fourth means for calculating a direction difference between directions represented by the selected two first data pieces;

eighth means connected to the seventh means for deciding whether or not the direction difference calculated by the seventh means is greater than a predetermined direction difference;

ninth means connected to the sixth means for calculating a rotational-angle difference between tentative rotational angles represented by the selected two second data pieces;

tenth means connected to the fifth means, the eighth means, and the ninth means for calculating an amount of offset in the output signal of the first sensor in response to the time interval calculated by the fifth means and the rotational-angle difference calculated by the ninth means in cases where the eighth means decides that the direction difference calculated by the seventh means is equal to or smaller than the predetermined direction difference;

eleventh means connected to the first sensor and the tenth means for correcting the output signal of the first sensor into an offset-free signal in response to the offset amount calculated by the tenth means; and

twelfth means connected to the eleventh means for integrating the offset-free signal to generate a signal representing a final rotational angle of the vehicle body.

5. The vehicle rotational-angle calculating apparatus of claim 1, further comprising thirteenth means connected to the second means and the third means for storing each of the first data pieces and the second data pieces during a predetermined length of time.

6. The vehicle rotational-angle calculating apparatus of claim 1, further comprising thirteenth means connected to the second sensor for detecting an accuracy of the output signal of the second sensor, and fourteenth means connected to the tenth means and the thirteen means for controlling the offset amount calculated by the tenth means in response to the accuracy detected by the thirteenth means.

7. The vehicle rotational-angle calculating apparatus of claim 1, further comprising thirteenth means connected to the tenth means for deciding whether or not the offset amount calculated by the tenth means is in a predetermined range, and fourteenth means connected to the eleventh means and the thirteenth means for controlling the correction by the eleventh means in response to whether or not the offset amount calculated by the tenth means is in the predetermined range.

8. The vehicle rotational-angle calculating apparatus of claim 1, further comprising thirteenth means connected to the second sensor and the first means for periodically calculating a direction difference between the vehicle body direction represented by the output signal of the second sensor and the tentative rotational angle represented by the signal generated by the first means, fourteenth means connected to the thirteenth means for averaging latest and previous direction differences calculated by the thirteenth means into a mean direction difference during every given interval, fifteenth means connected to the fourteenth means for separating latest and previous mean direction differences calculated by the fourteenth means into groups according to related vehicle body directions, and sixteenth means connected to the fifteenth means and contained in the tenth means for determining the offset amount in response to mean direction differences in same one of the groups.

2. A vehicle rotational-angle calculating apparatus comprising:

a first sensor outputting a signal representing an angular rate of a vehicle body;

a second sensor outputting a signal representing a direction of the vehicle body;

first means connected to the first sensor for integrating the output signal of the first sensor to generate a signal representing a tentative rotational angle of the vehicle body;

second means connected to the second sensor for generating first data pieces representing temporally spaced samples of the output signal of the second sensor respectively;

third means connected to the first means for generating second data pieces representing temporally spaced samples of the signal generated by the first means respectively;

fourth means connected to the second means for selecting a first pair of first data pieces and a second pair of first data pieces from among the first data pieces generated by the second means;

fifth means connected to the third means for selecting a first pair of second data pieces and a second pair of second data pieces from among the second data pieces generated by the third means, wherein the two second data pieces in the first pair relate to occurrence moments corresponding to the occurrence moments of the first data pieces in the first pair respectively, and the two second data pieces in the second pair relate to occurrence moments corresponding to the occurrence moments of the first data pieces in the second pair respectively;

sixth means connected to the fourth means for calculating a first direction difference between directions represented by the two first data pieces in the first pair, and a second direction difference between directions represented by the two first data pieces in the second pair;

seventh means connected to the fifth means for calculating a first rotational-angle difference between tentative rotational angles represented by the two second data pieces in the first pair, and a second rotational-angle difference between tentative rotational angles represented by the two second data pieces in the second pair;

eighth means connected to the sixth means for calculating a difference between the first direction difference and the second direction difference calculated by the sixth means;

ninth means connected to the seventh means for calculating a difference between the first rotational-angle difference and the second rotational-angle difference calculated by the seventh means;

tenth means connected to the eighth means and the ninth means for calculating a sensitivity coefficient related to the output signal of the first sensor in response to the difference calculated by the eighth means and the difference calculated by the ninth means;

eleventh means connected to the first sensor and the tenth means for correcting a magnitude of the output signal of the first sensor in response to the sensitivity coefficient calculated by the tenth means to convert the output signal of the first sensor into a gain-corrected signal; and

twelfth means connected to the eleventh means for integrating the gain-corrected signal to generate a signal representing a final rotational angle of the vehicle body.

3. A vehicle rotational-angle calculating apparatus comprising:

a first sensor outputting a signal representing an angular rate of a vehicle body;

a second sensor outputting a signal representing a direction of the vehicle body;

first means connected to the first sensor for integrating the output signal of the first sensor to generate a signal representing a tentative rotational angle of the vehicle body;

second means connected to the second sensor for generating first data pieces representing temporally spaced samples of the output signal of the second sensor respectively;

third means connected to the first means for generating second data pieces representing temporally spaced samples of the signal generated by the first means respectively;

fourth means connected to the second means for selecting a first pair of first data pieces and a second pair of first data pieces from among the first data pieces generated by the second means;

fifth means connected to the fourth means for calculating a first time interval between the occurrence moments of the two first data pieces in the first pair, and a second time interval between the occurrence moments of the two first data pieces in the second pair;

sixth means connected to the third means for selecting a first pair of second data pieces and a second pair of second data pieces from among the second data pieces generated by the third means, wherein the two second data pieces in the first pair relate to occurrence moments corresponding to the occurrence moments of the first data pieces in the first pair respectively, and the two second data pieces in the second pair relate to occurrence moments corresponding to the occurrence moments of the first data pieces in the second pair respectively;

seventh means connected to the fourth means for calculating a first direction difference between directions represented by the two first data pieces in the first pair, and a second direction difference between directions represented by the two first data pieces in the second pair;

eighth means connected to the fifth means for calculating a sum of the first time interval and the second time interval calculated by the fifth means;

ninth means connected to the seventh means for calculating a sum of the first direction difference and the second direction difference calculated by the seventh means;

tenth means connected to the eighth means for deciding whether or not the sum calculated by the eighth means is smaller than a predetermined time interval;

eleventh means connected to the ninth means for deciding whether or not the sum calculated by the ninth means is greater than a predetermined direction difference;

twelfth means connected to the sixth means for calculating a first rotational-angle difference between tentative rotational angles represented by the two second data pieces in the first pair, and a second rotational-angle difference between tentative rotational angles represented by the two second data pieces in the second pair;

thirteenth means connected to the twelfth means for calculating a sum of the first rotation-angle difference and the second rotational-angle difference calculated by the twelfth means;

fourteenth means connected to the eighth means, the tenth means, the eleventh means, and the thirteenth means for calculating an amount of offset in the output signal of the first sensor in response to the sum calculated by the eighth means and the sum calculated by the thirteenth means in cases where the tenth means decides that the sum calculated by the eighth means is equal to or greater than the predetermined time interval and the eleventh means decides that the sum calculated by the ninth means is equal to or smaller than a predetermined direction difference;

fifteenth means connected to the first sensor and the fourteenth means for correcting the output signal of the first sensor into an offset-free signal in response to the offset amount calculated by the fourteenth means;

sixteenth means connected to the seventh means for calculating a difference between the first direction difference and the second direction difference calculated by the seventh means;

seventeenth means connected to the twelfth means for calculating a difference between the first rotational-angle difference and the second rotational-angle difference calculated by the twelfth means;

eighteenth means connected to the sixteenth means and the seventeenth means for calculating a sensitivity coefficient related to the output signal of the first sensor in response to the difference calculated by the sixteenth means and the difference calculated by the seventeenth means;

nineteenth means connected to the first sensor and the eighteenth means for correcting a magnitude of the output signal of the first sensor in response to the sensitivity coefficient calculated by the eighteenth means to convert the output signal of the first sensor into a gain-corrected signal; and

twentieth means connected to the nineteenth means for integrating the gain-corrected signal to generate a signal representing a final rotational angle of the vehicle body.

4. A vehicle rotational-angle calculating apparatus comprising:

a first sensor outputting a signal representing an angular rate of a vehicle body;

a second sensor outputting a signal representing a direction of the vehicle body;

first means connected to the first sensor for integrating the output signal of the first sensor to generate a signal representing a tentative rotational angle of the vehicle body;

second means connected to the second sensor for generating first data pieces representing temporally spaced samples of the output signal of the second sensor respectively;

third means connected to the first means for generating second data pieces representing temporally spaced samples of the signal generated by the first means respectively;

fourth means connected to the second means for selecting a first pair of first data pieces and a second pair of first data pieces from among the first data pieces generated by the second means;

fifth means connected to the fourth means for calculating a first time interval between the occurrence moments of the two first data pieces in the first pair, and a second time interval between the occurrence moments of the two first data pieces in the second pair;

sixth means connected to the third means for selecting a first pair of second data pieces and a second pair of second data pieces from among the second data pieces generated by the third means, wherein the two second data pieces in the first pair relate to occurrence moments corresponding to the occurrence moments of the first data pieces in the first pair respectively, and the two second data pieces in the second pair relate to occurrence moments corresponding to the occurrence moments of the first data pieces in the second pair respectively;

seventh means connected to the fourth means for calculating a first direction difference between directions represented by the two first data pieces in the first pair, and a second direction difference between directions represented by the two first data pieces in the second pair;

eighth means connected to the fifth means for calculating a sum of the first time interval and the second time interval calculated by the fifth means;

ninth means connected to the seventh means for calculating a sum of the first direction difference and the second direction difference calculated by the seventh means;

tenth means connected to the eighth means for deciding whether or not the sum calculated by the eighth means is smaller than a predetermined time interval;

eleventh means connected to the ninth means for deciding whether or not the sum calculated by the ninth means is greater than a predetermined direction difference;

twelfth means connected to the sixth means for calculating a first rotational-angle difference between tentative rotational angles represented by the two second data pieces in the first pair, and a second rotational-angle difference between tentative rotational angles represented by the two second data pieces in the second pair;

thirteenth means connected to the twelfth means for calculating a sum of the first rotation-angle difference and the second rotational-angle difference calculated by the twelfth means;

fourteenth means connected to the eighth means, the tenth means, the eleventh means, and the thirteenth means for calculating an amount of offset in the output signal of the first sensor in response to the sum calculated by the eighth means and the sum calculated by the thirteenth means in cases where the tenth means decides that the sum calculated by the eighth means is equal to or greater than the predetermined time interval and the eleventh means decides that the sum calculated by the ninth means is equal to or smaller than a predetermined direction difference;

fifteenth means connected to the first sensor and the fourteenth means for correcting the output signal of the first sensor into an offset-free signal in response to the offset amount calculated by the fourteenth means; and

sixteenth means connected to the fifteenth means for integrating the offset-free signal to generate a signal representing a final rotational angle of the vehicle body.