Vehicle automatic transmission control system

• US 5,036,730 A
• Filed: 06/16/1989
• Issued: 08/06/1991
• Est. Priority Date: 06/17/1988
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Matsui, Hiroki, Yamamoto, Masataka, Sakai, Ichiro, Arai, Yasuhisa
• Primary Examiner(s): Herrmann, Allan D.
• Assistant Examiner(s): Levi, Benjamin
• Application Number:
  US07/368,191
• Time in Patent Office: 781 Days
• Field of Search: 74/866, 180/170, 364/424.1, 364/424.01, 364/164, 364/807, 364/426.01, 364/513
• US Class Current: 701/57
• CPC Class Codes: B60W 2050/0057 Frequency analysis, spectral techniques or transforms
• CPC Class Codes: F16H 2059/183 Rate of change of accelerator position, i.e. pedal or throttle change gradient
• CPC Class Codes: F16H 2061/0081 Fuzzy logic
• CPC Class Codes: F16H 2061/161 by checking feasibility of shifts, i.e. determine if requested shift can be successfully completed and post shift values are in an acceptable range
• CPC Class Codes: F16H 59/24 dependent on the throttle opening
• CPC Class Codes: F16H 59/66 Road conditions, e.g. slope, slippery
• CPC Class Codes: F16H 59/74 Inputs being a function of engine parameters F16H59/14 takes precedence
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/686 with orbital gears
• CPC Class Codes: Y10S 706/90 Fuzzy logic

Abstract

A system for controlling automatic, multi-step or continuously variable, transmission equipped with a motor vehicle utilizing fuzzy logic. In the system, fuzzy production rules have been prepared based upon an expert driver'"'"'s judgments and operation made on a vehicle with a manually shifted transmission. Various operating conditions including opening degree of a throttle valve and road speed of the vehicle are detected and from the detected value, various predictions are made such as an appropriateness of vehicle response to a gearshift intended by the driver and engine output change that would occur should the transmission be shifted to a given gear. These measured or estimated value are put on a common scale named universe of discourse and membership values of the rules are successively calculated. Among the rules, one rule is finally selected and according to the gear indicated in the selected rule, the current gear is shifted up or down or is held at the present position, in case of the multi-step transmission. Similarly, the speed ratio in the continuously variable transmission is determined from the selected rule.

Claims

1. A system for controlling a vehicle automatic multi-step geared or continuously variable transmission, comprising:

first means for detecting operating conditions of the vehicle including engine speed, degree of throttle opening, change in the throttle opening degree, vehicle speed, change in the vehicle speed and gear ratio currently engaged;

second means for predicting, with respect to gear ratios to which it is possible to shift from the gear ratio currently engaged, reserve motive force available and change in the engine speed, which would occur upon shifting to each of said gear ratios not currently engaged;

third means for establishing a membership function of a fuzzy set of detected and predicted parameters including the detected operating conditions of the vehicle, in accordance with a plurality of predetermined fuzzy production rules defining gear ratio shifting;

fourth means for carrying out fuzzy reasoning based on the rules using the detected and predicted parameters to determine a gear ratio to be shifted to; and

actuator means for driving a gear ratio shift mechanism in response to the determined gear ratio.

2. A system according to claim 1, wherein said reserve motive force is used in at least one of the rules which defines upshifting.

3. A system according to claim 1, wherein said reserve motive force available is calculated from a gradient of a road surface on which the vehicle is traveling.

4. A system according to claim 1, 2, or 3, wherein said fourth means carries out fuzzy reasoning on a ratio change coefficient and determines the gear ratio to be shifted to, by multiplying the gear ratio currently engaged by the ratio change coefficient.

5. A system according to claim 1, 2, or 3, wherein said rules are established on the basis of an analysis of judgments and feelings of a driver of a vehicle with a manually shifted transmission.

6. A system for controlling a vehicle automatic transmission, comprising:

first means for determining operating conditions of the vehicle including degree of throttle opening, vehicle speed, and gear ratio currently engaged;

second means for establishing a membership function of a fuzzy set for each of a plurality of parameters from the determined operating conditions in accordance with a plurality of predetermined fuzzy production rules defining a plurality of respective gear ratio shifting conclusions;

third means for carrying out fuzzy reasoning based on the fuzzy production rules to determined said respective gear ratio shifting conclusions and to determine a target gear ratio shift based on the gear ratio shifting conclusions from the gear ratio currently engaged; and

actuator means for driving a gear ratio shift mechanism in response to the determined target gear ratio shift.

7. A system according to claim 6, wherein said third means determines the target gear ratio by calculating the membership function of the rules to select one rule and wherein the calculated membership function is then compared with a prescribed value and if the calculated membership function is found to be not larger than the prescribed value, the selection of said one rule is cancelled.

8. A system according to claim 6, wherein said rules include a rule whose membership function complements that of another rule.

9. A system according to claim 6, wherein said membership function has a maximum membership function which differs among said rules.

10. A system according to claim 9, wherein said rule assigned the maximum membership function is a rule for protecting the engine from damage.

11. A system according to claim 7, 8, 9, 10 or 6 wherein said rules are established on the basis of an analysis of judgments and feelings of a driver of a vehicle with a manually shifted transmission.