Clutch Pressure Control via Feedforward Feedback Segmentation

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Solution Overview

Problem

Double-clutch transmissions require an optimized control strategy for hydraulic pressure management to handle varying operating conditions effectively, as existing methods lack flexibility and adaptability to changes in hardware components and operating parameters.

Innovation Solution

A fully model-based control strategy for hydraulic pressure in double-clutch transmissions, which includes a feedforward and feedback approach to calculate target currents for proportional hydraulic valves, allowing for flexible and adaptive pressure control by modeling steady-state and dynamic influences of components, enabling separation of higher-level software from clutch control and facilitating concurrent engineering and reusability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional pressure control method is used, then the control system is simpler, but the flexibility and adaptability to hardware changes are reduced

Engineering Contradiction:
Improveadaptability to hardware changesVSAvoidcontrol strategy complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control strategy is segmented into modular components: a feedforward control module that handles adaptive adjustments based on hardware parameters, and a feedback control module that maintains stability. This segmentation allows the system to adapt to hardware changes through parameter updates in the feedforward module without requiring complete retuning, thus improving adaptability while managing complexity through structured organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system utilizes parameter changes in the feedforward control module to adapt to different hardware configurations. By adjusting feedforward parameters based on hardware specifications, the system achieves high adaptability to hardware changes without increasing overall control complexity, as the feedback module continues to operate with standard tuning.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If a fully model-based feedforward control strategy is used, then the flexibility and performance are improved, but the device complexity increases

Engineering Contradiction:
Improvepressure control performanceVSAvoidcontrol strategy structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The control strategy is divided into feedforward and feedback segments, where the feedforward portion implements the model-based approach for high performance, while the feedback portion provides stabilization. This segmentation allows the system to achieve high productivity through accurate model-based feedforward control without excessive overall complexity, as the feedback module handles deviations with standard control algorithms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The feedback control module acts as an intermediary that compensates for inaccuracies and disturbances in the model-based feedforward control. This intermediary feedback mechanism ensures high pressure control performance by correcting deviations, while keeping the overall system complexity manageable through the use of conventional feedback algorithms rather than requiring a completely complex model-based feedback system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the control strategy is highly adaptive to hardware changes, then the ease of manufacture and reusability are improved, but the initial development complexity increases

Engineering Contradiction:
Improvereusability of control strategyVSAvoidmodel-based control structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The control strategy is segmented into parameter-dependent feedforward components and structure-stable feedback components. This segmentation improves ease of manufacture and reusability because hardware changes only require updating feedforward parameters rather than redesigning the entire control structure. The feedback module maintains its standard structure across different applications, reducing development complexity for new projects.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The feedback control module provides universal functionality that can be applied across different hardware configurations without modification. This universality improves reusability of the control strategy, as the same feedback structure can be reused in various applications while only the feedforward parameters need adjustment for different hardware, thereby reducing initial development complexity for new projects.

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

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution provides high flexibility, adaptability, and performance in clutch pressure control, ensuring optimal operation under changing conditions without the need for full retuning of the control strategy, even when hardware components change, and maintains high control quality across various situations.

Implementation Method 1

a proportional valve (32) having an electrical signal input and a hydraulic output to the clutch (20)

Methodology Applied
Scientific EffectHydraulic control: Hydraulic Press

Implementation Method 2

a solenoid (31) wound around the proportional valve spool (322)

Methodology Applied
Scientific EffectElectrohydraulic actuation: Electromagnet

Implementation Method 3

a solenoid (31) wound around the proportional valve spool (322)

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Data Source

PatentEP2233766B1Clutch pressure control device
Publication Date: 2012.06.27 HOERBIGER DRIVETRAIN MECHATRONICS B A
  • EP2233766B1 patent drawingFigure 1
  • EP2233766B1 patent drawingFigure 2
  • EP2233766B1 patent drawingFigure 3~5

AI summary

The invention concerns a clutch pressure control device (1) comprising a request filter unit (2) calculating a target clutch pressure value (p_dutch_tgt) from a requested clutch pressure value (p_req) input in the request filter unit (2); a feedforward clutch pressure control model unit (3) calculating, from the target clutch pressure value (p_tgt) input by the request filter unit (2), a feedforward current value (i_OL); a PID control unit (4) calculating a feedback current value (i_CL) from a valve pressure target value (p_valve_tgt) for a hydraulic proportional valve controlling the clutch pressure and a feedback actual pressure value (p_actual); a first calculation unit (5) calculating a hydraulic proportional valve target current value (i_tot) from the input feedforward current value (i_OL) and the feedback current value (i_CL); a description of the measurement methods to find the values for the following adaption parameters: the kisspoint pressure of the clutch, the preload pressure of the clutch and the fill volume of the clutch.