Vehicle Control Apparatus Thrust Force Accuracy
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Solution Overview
Problem
Existing electric brake apparatuses lack precise control over the thrust force of independently controllable pistons, leading to inaccuracies in braking force application.
Innovation Solution
A vehicle control system that includes a control portion to calculate and output instructions for actuating first and second thrust portions based on a target thrust force instruction value, improving the accuracy of thrust force control by adjusting the actuation of both pistons according to a physical amount related to the change in the target thrust force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two pistons are actuated alternately or simultaneously without specific control order, then the braking force can be applied to the wheel, but the accuracy of controlling the piston thrust force deteriorates
Solution Approach 1:
The control of piston actuation is segmented into distinct phases: a first piston is actuated first when the target thrust force increases, followed by actuation of a second piston. This segmentation of the actuation process allows for precise control of the thrust force buildup, preventing excessive thrust force differences between pistons while maintaining reliable braking force application.
2Ease of operation
If the actuation order of two pistons is not specified, then the control system is simpler to operate, but the accuracy of controlling the thrust force deteriorates
Solution Approach 1:
The control system dynamically adjusts the actuation sequence of pistons based on the direction of thrust force change. When the target thrust force increases, pistons are actuated in a specific sequence (first piston then second piston). When the target thrust force decreases, the actuation sequence is reversed. This dynamic adaptation maintains high control accuracy without requiring complex predetermined sequences for all operating conditions.
3Device complexity
If pistons are actuated without considering the change in target thrust force, then the control process is simpler, but the difference in thrust forces between pistons increases
Solution Approach 1:
The control system continuously monitors the target thrust force and adjusts piston actuation based on feedback regarding the change in thrust force. The control unit determines whether the target thrust force is increasing or decreasing and modifies the actuation sequence accordingly. This feedback mechanism ensures that thrust force differences between pistons are minimized while maintaining a relatively simple control process structure.
Data Source
AI summary
Left front electric brake mechanisms apply a braking force to a left front wheel by actuating an “electric motor of a first left front electric brake mechanism” and an “electric motor of a second left front electric brake mechanism” controllable independently of each other. A first ECU (a control portion) acquires a target thrust force instruction value to be generated on the left front electric brake mechanisms based on a target braking force to be applied to the left front wheel. The first ECU (the control portion) outputs a first control instruction for actuating the electric motor of the first left front electric brake mechanism and a second control instruction for actuating the electric motor of the first left front electric brake mechanism according to a change amount of the target thrust force instruction value.