Vehicle Brake Control Device Inertia Compensation

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Solution Overview

Problem

Existing vehicle brake control devices face challenges in compensating for inertia influences during acceleration and deceleration, leading to response delays and overshoots due to the inertia of the electric motor and overall device, which existing methods like gradient limitation fail to address effectively.

Innovation Solution

A vehicle brake control device that determines the necessity of inertia compensation based on operation amounts and calculates specific inertia compensation energization patterns to adjust the target energization amount, using time-series patterns for acceleration and deceleration phases to improve responsiveness and reduce overshoot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If gradient limitation is provided against the indication current to ensure stable control, then control stability is improved, but the target motor rotation angular acceleration cannot be correctly calculated, resulting in insufficient inertia compensation

Engineering Contradiction:
Improvecontrol stabilityVSAvoidinertia compensation precision
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent segments the control process into two distinct phases: a gradient limitation phase for stable control, and an inertia compensation phase for precise acceleration compensation. By separating these functions into different control stages, the system can apply gradient limitation to ensure stability while independently calculating inertia compensation based on actual motor acceleration, thus resolving the contradiction between stability and precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary calculation of the target motor rotation angular acceleration before applying gradient limitation to the indication current. By pre-calculating the acceleration value based on the map data and operation amount, the system preserves the accuracy needed for inertia compensation while still applying gradient limitation for stable control execution.

Inventive Principle:
Principle #10Preliminary action

2Speed

If inertia compensation current is calculated based on target motor rotation angular acceleration from indication current, then responsiveness during acceleration is improved, but overshoot during deceleration occurs due to incorrect acceleration calculation under gradient limitation

Engineering Contradiction:
Improveresponsiveness of braking torqueVSAvoidbraking torque convergence
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent introduces feedback mechanisms to monitor actual motor rotation speed and calculate actual acceleration values. By comparing target indication current with actual motor response, the system can accurately determine when inertia compensation is needed and calculate appropriate compensation values, preventing both responsiveness loss and overshoot issues.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically adjusts the control strategy based on motor operation state. During acceleration phases, inertia compensation is actively applied to improve responsiveness. During deceleration phases, the system dynamically switches to a different control mode that prevents overshoot, thereby adapting to different operational requirements in real-time.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2786907B1Braking control device for vehicle
Publication Date: 2020.01.08 ADVICS CO LTD
  • EP2786907B1 patent drawingFigure 1
  • EP2786907B1 patent drawingFigure 2
  • EP2786907B1 patent drawingFigure 3

AI summary

In this device, an electric motor is controlled based on a target energization amount calculated based on an operation amount (Bpa) of a braking operation member. Based on the operation amount (Bpa), it is determined whether or not an inertia compensation control for compensating for the influence of the inertia of a brake actuator is necessary. When the inertia compensation control is determined to be necessary (FLj←1 or FLk←1), an inertia compensation energization amount (Ijt, Ikt) for compensating for the influence of the inertia of the brake actuator is calculated based on a time-series pattern (CHj, CHk) set in advance based on the maximum response of the brake actuator. Based on the inertia compensation energization amount (Ijt, Ikt), the target energization amount is calculated. Consequently, it is possible to provide a vehicle brake control device which causes an electric motor to generate a braking torque and which is capable of appropriately compensating for the influence of the inertia of the entire device including the inertia of the electric motor.