Electric Braking Device Wheel Slip Control
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Solution Overview
Problem
Existing vehicle electric braking systems face challenges in effectively controlling wheel slip during bidirectional multiplex communication due to communication cycle delays, which can lead to increased wheel slip and reduced responsiveness in slip restriction control.
Innovation Solution
The system includes a body electronic control unit and a wheel electronic control unit connected by a communication line, where the wheel speed sensor directly inputs wheel speed to the wheel electronic control unit, allowing it to adjust the electric motor output based on calculated body speed and wheel speed without time delays, thereby executing wheel slip restriction control accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If wheel speed is transmitted from wheel electronic control unit to body electronic control unit via communication line for body speed calculation, then system architecture is simplified and cost is reduced, but communication cycle delays occur causing increased wheel slip
Solution Approach 1:
The patent divides the control function into two parts: the body electronic control unit calculates body speed using wheel speed data transmitted via communication line, while the wheel electronic control unit independently performs wheel slip restriction control using locally acquired wheel speed data. This segmentation allows the system to maintain simplified architecture while ensuring reliable slip control through distributed intelligence.
Solution Approach 2:
The wheel electronic control unit acquires wheel speed data directly from the wheel speed sensor in advance, before communication delays occur. This preliminary acquisition of critical control data enables the wheel slip restriction control to respond immediately without waiting for data transmission and processing cycles.
2Ease of manufacture
If wheel speed is transmitted via communication line between control units, then cable costs are reduced, but responsiveness of slip restriction control deteriorates
Solution Approach 1:
The system separates the data acquisition function from the control execution function. The wheel electronic control unit independently acquires wheel speed data directly from the sensor, eliminating the need for rapid transmission of this critical data. This segmentation allows use of lower-cost communication lines while maintaining high control responsiveness through local data availability.
Solution Approach 2:
The wheel electronic control unit serves itself by directly acquiring wheel speed data from the wheel speed sensor without requiring data transmission from other control units. This self-service capability ensures immediate access to wheel speed information for slip restriction control, maintaining high responsiveness while reducing communication infrastructure costs.
3Extent of automation
If body electronic control unit calculates body speed using transmitted wheel speed data, then centralized control is achieved, but communication delays increase control cycle time
Solution Approach 1:
The patent segments the control architecture so that the body electronic control unit performs centralized body speed calculation using transmitted wheel speed data, while the wheel electronic control unit independently executes wheel slip restriction control using locally acquired wheel speed data. This segmentation eliminates the need for the wheel slip control to wait for body speed calculation, reducing control cycle time while maintaining centralized monitoring capabilities.
Solution Approach 2:
The wheel electronic control unit performs preliminary acquisition of wheel speed data directly from the sensor before the body electronic control unit completes its body speed calculation. This preliminary action ensures that critical control data is available immediately for slip restriction control, reducing the effective control cycle time for this safety-critical function.
Data Source
AI summary
This electric braking device for a vehicle imparts to the wheels of the vehicle a braking torque in accordance with the output of an electric motor. A vehicle body-side electronic control unit calculates a command value for the output of the electric motor on the basis of the amount of operation performed on a braking operation member. A wheel-side electronic control unit adjusts the output of the electric motor on the basis of the command value. The vehicle body-side electronic control unit calculates the vehicle body speed on the basis of the wheel speed. The wheel-side electronic control unit adjusts the output of the electric motor so as to prevent an increase in slippage of the wheels on the basis of the vehicle body speed and the wheel speed.