Electric Brake Apparatus Characteristic Data Correction
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Solution Overview
Problem
The existing electric brake apparatus may generate an actual braking hydraulic pressure that deviates from the desired pressure due to direct updates of brake characteristics using detected piston movement and pressure, leading to inaccuracies in braking performance.
Innovation Solution
An electric brake apparatus with an electric actuator, operation amount detector, movement amount detector, and controller that corrects characteristic data indicating the relationship between hydraulic pressure and piston movement based on brake pedal operation, allowing accurate generation of desired braking pressure by storing and applying corrected data for both manual and automatic braking instructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If brake characteristic is updated using direct detection of piston movement amount and generated hydraulic pressure, then the system can operate with simple detection mechanisms, but the actual braking hydraulic pressure deviates from the desired pressure
Solution Approach 1:
The system uses feedback control by detecting the actual braking hydraulic pressure through the inter-apparatus communication network, comparing it with the desired pressure, and correcting the characteristic data based on the difference. This feedback mechanism enables accurate pressure control while maintaining relatively simple detection mechanisms.
Solution Approach 2:
The patent replaces direct mechanical detection of piston movement with an alternative approach using inter-apparatus communication network to obtain braking hydraulic pressure information. This substitution allows for more accurate pressure measurement without requiring complex mechanical detection systems for piston position.
2Reliability
If characteristic data is corrected based on brake pedal operation, then accurate braking pressure can be generated, but the system requires complex coordination between multiple detection systems
Solution Approach 1:
The controller performs multiple functions using the same characteristic data correction mechanism: it corrects data based on brake pedal operation detection, applies corrections to both manual and automatic braking modes, and ensures consistent braking performance across different operating conditions. This multi-functionality approach reduces the need for separate systems for different braking scenarios.
Solution Approach 2:
The system performs preliminary correction of characteristic data during brake pedal operation before actual automatic braking occurs. This preliminary action ensures that when automatic braking is needed, the corrected characteristic data is already available, improving reliability without requiring complex real-time coordination during emergency braking situations.
3Adaptability or versatility
If the system uses inter-apparatus communication network for braking instructions, then automatic braking functions can be integrated, but communication delays may affect pressure generation accuracy
Solution Approach 1:
The system creates a corrected copy of the characteristic data that compensates for communication delays. By detecting brake pedal operation and correcting the characteristic data in advance, the system generates an accurate representation of the desired braking pressure that accounts for timing differences in the communication network, ensuring precise pressure generation despite integration delays.
Data Source
AI summary
An electric brake apparatus includes an electronic control unit (ECU) configured to move a power piston to cause a braking hydraulic pressure to be generated in a master cylinder by controlling an electric motor of an electric actuator based on an operation on a brake pedal (an input member position). A characteristic update processing portion of the ECU is configured to update, based on an operation amount of the brake pedal, characteristic data indicating a relationship between a hydraulic value transmitted from the ECU via a vehicle data bus and a movement amount of the power piston controlled based on the input member position, and store the updated characteristic data. The ECU is configured to control the electric actuator based on the updated characteristic data when an automatic brake instruction is input.