Parking Brake Force Estimation via Electrical Measurement

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Solution Overview

Problem

Existing parking brake systems rely on position sensors to determine the position of the actuator assembly and brake piston, which increases cost, space, and weight, and may not comply with updated vehicle guidelines; there is a need for a method to accurately estimate and control the parking brake force without using a position sensor.

Innovation Solution

A method that measures voltage and current during parking brake application or release to estimate the position of the motor, actuator assembly, and brake piston, and relates translational displacement to parking brake force using a linear time variant estimation model, allowing for accurate determination of parking brake force creation and release without a position sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a position sensor is used to determine the position of the actuator assembly and brake piston, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improveposition determination accuracyVSAvoidsystem complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical position sensor system with an electrical measurement system. The control unit determines actuator assembly position by measuring electrical quantities (current, voltage) and applying mathematical models, substituting the physical sensor mechanism with an electrical-field-based measurement approach that reduces mechanical complexity while maintaining measurement capability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electrical measurements (current and voltage) as intermediary variables to indirectly determine position. Instead of directly measuring position with a sensor, the system measures easily obtainable electrical quantities and uses these as intermediaries to calculate position through mathematical relationships, simplifying the overall measurement system

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a position sensor is used to determine the position of the actuator assembly and brake piston, then measurement precision is improved, but weight increases

Engineering Contradiction:

Improveposition determination accuracyVSAvoidsystem weight

Core Design Contradiction:

Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent eliminates the physical position sensor hardware by substituting it with an electrical measurement system. The control unit uses electrical current and voltage measurements combined with mathematical modeling to determine position, removing the need for heavy mechanical sensors and reducing overall system weight

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a virtual model or mathematical representation of the actuator assembly position based on electrical measurements. Instead of physically sensing position, the system creates a computational copy of the position information through mathematical relationships between electrical quantities and mechanical displacement, eliminating the need for physical sensing hardware

Inventive Principle:

Principle #26Copying

3Measurement precision

If a position sensor is used to determine the position of the actuator assembly and brake piston, then measurement precision is improved, but cost increases

Engineering Contradiction:

Improveposition determination accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive position sensor hardware with a cost-effective electrical measurement system. By using standard electrical sensors (current and voltage measurements) and computational algorithms, the system achieves position determination capability without requiring specialized mechanical sensors, significantly reducing manufacturing costs

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables the existing electrical system components to serve dual purposes. The motor's current and voltage measurements, originally intended for basic motor control, are also used to determine actuator assembly position. This self-service approach eliminates the need for separate position sensing hardware, reducing overall system cost

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS10137878B2Method for controlling a parking brake system

Publication Date: 2018.11.27 AKEBONO BRAKE IND CO LTD

AI summary

A method that includes steps of measuring voltage and current of the parking brake system during creation of a parking brake apply or release of the parking brake apply. The method includes estimating motor position, motor speed, and a current draw of the motor using the measured voltage and the measured current. The method includes estimating a parking brake force with the estimated motor position. The method includes correcting the estimated motor position, motor speed, and the current draw of the motor with the measured current, and/or correcting the estimated parking brake force with the corrected estimated motor position, corrected motor, and the corrected current draw of the motor. The method includes determining the creation of the parking brake apply with the corrected parking brake force and/or determining release of the parking brake apply with the corrected estimated motor position.