Automatic Transmission Oil Pressure Learning for Clutch Wear Adaptation

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Solution Overview

Problem

Existing oil pressure adjustment methods for automatic transmissions fail to accurately account for changes in clutch or brake characteristics over time, leading to inadequate oil pressure adjustments.

Innovation Solution

An oil pressure learning method that uses reinforcement learning to adjust oil pressure based on detected input rotation speed, gear-shift time, heat generation, and torque changes, updating relational regulation data to optimize oil pressure command values for improved transmission performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If oil pressure is adjusted simply based on the blow amount of the input rotation speed, then the control method is simple, but the oil pressure cannot be appropriately adjusted according to the change in the characteristics of the automatic transmission

Engineering Contradiction:
Improvesimplicity of control methodVSAvoidappropriateness of oil pressure adjustment
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements feedback mechanisms by detecting multiple parameters (blow amount, gear-shift time, heat generation amount) and using them to update relational regulation data through reinforcement learning. The system continuously monitors transmission characteristics and adjusts oil pressure commands based on feedback from these detections, ensuring appropriate adaptation to clutch/brake wear while maintaining a structured control framework.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes multiple parameters simultaneously for comprehensive adjustment: it detects blow amount, gear-shift time, and heat generation amount; calculates torque variables based on input torque changes; and updates relational regulation data with learned values. This multi-parameter approach allows appropriate oil pressure adjustment according to transmission characteristics while avoiding oversimplification.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If reinforcement learning is used to update relational regulation data with multiple variables, then the oil pressure adjustment accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improveoil pressure adjustment accuracyVSAvoidcomplexity of control system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control device performs multiple functions using a unified reinforcement learning framework: it detects various parameters (blow amount, gear-shift time, heat generation), calculates torque variables, updates relational regulation data, and generates oil pressure commands. This multi-functional approach improves adjustment accuracy while avoiding the need for separate complex systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses itself to improve its own performance through reinforcement learning. The control device detects its own operational parameters, calculates performance metrics (blow amount, gear-shift time, heat generation), and autonomously updates its relational regulation data based on learned experiences. This self-service mechanism improves accuracy without requiring external complex adjustment systems.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the relational regulation data is updated frequently to adapt to changing transmission characteristics, then the adaptability is improved, but the stability of the control system may deteriorate

Engineering Contradiction:
Improveadaptability to transmission characteristicsVSAvoidstability of control system
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent updates relational regulation data based on learned values from reinforcement learning, which accumulates knowledge over multiple detection cycles. By preliminarily learning from past experiences and storing relational regulation data, the system adapts to transmission characteristics changes while maintaining stability through established learned patterns rather than making immediate abrupt changes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically balances adaptability and stability by using reinforcement learning to gradually update relational regulation data. The control device adapts to changing transmission characteristics (clutch/brake wear) over time through continuous learning, while the stability is maintained by building upon previously learned relational patterns rather than making sudden changes.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11421781B2Oil pressure learning method of automatic transmission, control device thereof, and control system thereof
Publication Date: 2022.08.23 TOYOTA JIDOSHA KK
  • US11421781B2 patent drawing
  • US11421781B2 patent drawing
  • US11421781B2 patent drawing

AI summary

An oil pressure learning method of an automatic transmission includes acquiring a state of a vehicle in a state where relational regulation data is stored, supplying oil to the automatic transmission such that the value of the oil pressure is set to an oil pressure command value, calculating, as a specific variable, a variable representing an amount in which a detected input rotation speed exceeds a target input rotation speed, or the like, calculating a reward in a manner in which it has a larger value when the specific variable satisfies a criterion than when it does not satisfy the criterion, updating the relational regulation data by inputting, to an update mapping, the reward and the oil pressure command value, and calculating a torque variable having a value that is increased as an amount of change in an input torque is increased.