Vehicle Suspension Control Using Antilock Braking Force
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Solution Overview
Problem
Existing suspension control systems for vehicles face challenges in accurately controlling damping force during antilock braking, as vibrations in brake hydraulic pressure can lead to inappropriate vehicle body behavior, necessitating a solution that distinguishes between ordinary and antilock braking conditions.
Innovation Solution
A suspension controlling apparatus with a control unit that calculates vehicle acceleration in both forward and rearward directions, using a hydraulic pressure sensor to determine damping force, and includes features such as acceleration calculation based on antilock braking force, a damping force map, engine torque calculation, and actual acceleration sensing to manage damping force variations effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If brake hydraulic pressure is used to calculate braking force during antilock braking control, then the suspension control can respond to braking operations, but the vibration of brake hydraulic pressure causes inappropriate vehicle body behavior control
Solution Approach 1:
The patent segments the braking control into two distinct modes: ordinary braking mode where hydraulic pressure is used for acceleration calculation, and antilock braking mode where a predetermined deceleration is used instead. This segmentation allows the system to avoid using the vibrating hydraulic pressure data during antilock braking while maintaining responsive control during ordinary braking.
Solution Approach 2:
The patent introduces an intermediary approach by using a predetermined deceleration value as a substitute for the actual hydraulic pressure-based acceleration calculation during antilock braking. This intermediary value filters out the vibrations in hydraulic pressure while still providing the necessary control input for suspension adjustment.
2Speed
If the damping force is varied rapidly to respond to vehicle body behavior, then the suspension control becomes more responsive, but the variation amount of damping force becomes excessively large causing instability
Solution Approach 1:
The patent applies preliminary action by setting a variation amount limit value in advance before control execution. This predetermined limit prevents the damping force from varying excessively while still allowing sufficient adjustment range for effective suspension control during various driving conditions including antilock braking.
3Reliability
If the suspension control uses calculated acceleration during antilock braking, then appropriate control can be carried out, but the system complexity increases due to multiple calculation methods
Solution Approach 1:
The patent implements a dynamic calculation system that automatically switches between different acceleration calculation methods based on the braking mode. During ordinary braking, it uses hydraulic pressure-based calculation; during antilock braking, it uses predetermined deceleration. This dynamic adaptation maintains control reliability while managing system complexity through conditional logic.
Data Source
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AI summary
To make, in a suspension controlling apparatus for a vehicle which includes a suspension whose damping force is variably settable and a control unit which calculates acceleration of the vehicle in a forward and rearward direction on the basis of brake hydraulic pressure detected by a hydraulic pressure sensor for detecting brake hydraulic pressure and is capable of controlling the damping force of the suspension with target damping force determined on the basis of the acceleration, appropriate control possible also upon antilock braking control. [Solving Means] A control unit includes acceleration calculation means for calculating, upon ordinary braking, acceleration on the basis of ordinary braking force corresponding to a detection value of a hydraulic pressure sensor but calculating, upon antilock braking control, the acceleration on the basis of given antilock brake controlling braking force.