Vehicle Braking Control Using Suspension Pitch Frequency Compensation
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Solution Overview
Problem
Existing vehicle braking systems face challenges with repeated wheel slip and deterioration of wheel slip control performance due to longitudinal load movement, primarily because they do not effectively account for pitch motion characteristics and vertical load changes in real-time.
Innovation Solution
A filter-based feedforward/feedback control method is employed to determine and compensate for the braking force command, considering the natural frequency of vehicle suspension pitch motion by using a first filter to remove or decrease and a second filter to extract or increase this frequency component, thereby adjusting the braking force to prevent wheel slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional braking control is used without considering pitch motion, then the control system is simple, but wheel slip occurs repeatedly due to longitudinal load movement
Solution Approach 1:
The patent applies preliminary action by calculating and compensating for pitch motion effects before they cause wheel slip. The controller predicts longitudinal load movement based on pitch angle and rate of change, then adjusts braking force commands in advance to prevent slip, rather than reacting after slip occurs.
Solution Approach 2:
The patent implements feedback by continuously monitoring pitch angle and pitch rate from sensors, then using this information to dynamically adjust braking force distribution. The system feeds back actual pitch motion data to the controller, which modifies braking commands to maintain optimal tire-road contact and prevent wheel slip.
2Productivity
If braking force is increased to improve stopping performance, then braking efficiency improves, but wheel slip occurs due to reduced vertical load on driving wheels
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting braking force based on pitch motion parameters (pitch angle and pitch rate). When pitch motion reduces vertical load on driving wheels, the system modifies braking force parameters to stay within the reduced friction limit, preventing wheel slip while maintaining effective braking.
Solution Approach 2:
The patent implements dynamics by making braking force control adaptive to changing vehicle conditions. The system continuously adjusts braking force distribution based on real-time pitch motion data, transitioning from static braking control to dynamic control that responds to longitudinal load transfer during braking.
3Reliability
If pitch motion is not compensated, then manufacturing cost is low, but wheel slip control performance deteriorates
Solution Approach 1:
The patent uses feedback from existing pitch sensors to improve wheel slip control without adding major hardware. The controller processes pitch angle and pitch rate data from available sensors, converting existing sensor capabilities into enhanced braking control performance through software-based compensation algorithms.
Solution Approach 2:
The patent replaces complex mechanical solutions with electronic control. Instead of adding mechanical components to physically prevent pitch motion or load transfer, the system uses electronic sensors and controllers to detect and compensate for pitch effects through software algorithms, reducing manufacturing complexity.
Data Source
AI summary
A method for controlling braking of a vehicle includes determining a natural frequency of a vehicle suspension pitch motion according to characteristics of a suspension, providing a first filter configured to remove or decrease the natural frequency component of the vehicle suspension pitch motion and a second filter configured to extract or increase the natural frequency component of the vehicle suspension pitch motion, determining a total requested braking force command based on vehicle driving information collected while the vehicle is driven, determining a post-filter application total braking force command through a processing procedure by the first filter, determining a braking force compensation amount through a processing procedure by the second filter, and compensating for the post-filter application total braking force command using the braking force compensation amount, and controlling a braking force, which is applied to a wheel, using the post-compensation total braking force command.