Regenerative Braking Torque Control via Response Time Matching
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Solution Overview
Problem
In vehicle regenerative braking systems, the response time of the regenerative brake often precedes that of the frictional brake, potentially causing shocks due to the timing difference, and existing solutions involve delaying the regenerative brake response time, which can lead to inconsistent driver feedback.
Innovation Solution
A regenerative braking control device that computes a regenerative braking torque by matching the response time of the regenerative brake to the braking rate of the frictional brake based on vehicle speed and driver request, and releases this restriction when the driver's braking torque decreases, ensuring synchronized braking without unnecessary delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the response time of the regenerative brake is delayed to match the frictional brake, then shock is prevented, but driver feedback becomes inconsistent and braking performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the response time control of the regenerative brake adaptive rather than fixed. The control device dynamically adjusts the response time based on real-time driving conditions, vehicle speed, and brake pedal operation patterns. This allows the system to prevent shock when needed while maintaining responsive driver feedback when appropriate, resolving the contradiction between shock prevention and consistent driver feedback.
Solution Approach 2:
The patent changes the parameter of response time from a fixed delayed value to a variable parameter that adjusts based on driving conditions. By computing the regenerative brake response time based on vehicle speed, brake pedal position, and other operational parameters, the system optimizes the balance between shock prevention and driver feedback consistency across different operating scenarios.
2Object-affected harmful factors
If the response time of the regenerative brake is delayed to match the frictional brake, then shock is prevented, but braking efficiency and energy recovery are reduced
Solution Approach 1:
The system dynamically adjusts the regenerative brake response timing based on real-time conditions rather than applying a fixed delay. This allows the system to maximize energy recovery by engaging the regenerative brake as soon as conditions permit, while still preventing shock by coordinating with the frictional brake when necessary. The dynamic adjustment optimizes both shock prevention and braking efficiency simultaneously.
Solution Approach 2:
The response time parameter is changed from a static delayed value to a dynamic parameter that varies with vehicle speed, brake pedal operation, and system state. This enables the system to minimize unnecessary delays that would reduce braking efficiency while maintaining shock prevention through coordinated control of both frictional and regenerative brakes based on computed optimal timing.
3Object-affected harmful factors
If the response time of the regenerative brake is delayed to match the frictional brake, then shock is prevented, but system complexity increases due to additional control logic
Solution Approach 1:
The control device performs multiple functions within a single integrated system: it computes driver request braking torque, determines frictional brake torque, calculates optimal regenerative brake response time, and coordinates both brake systems. By consolidating these functions in one control unit with a unified computation framework, the patent reduces overall system complexity compared to separate control systems while still achieving shock prevention through coordinated control.
Solution Approach 2:
The patent uses parameter-based control where the regenerative brake response time is computed as a function of vehicle speed, brake pedal position, and other measurable parameters. This parameter-driven approach simplifies the control logic by using straightforward computational relationships rather than complex conditional rules, making the system easier to implement and manage while still achieving coordinated brake control for shock prevention.
Data Source
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AI summary
A regenerative braking control device for a vehicle includes: a driver request braking torque computation unit configured to compute a driver request braking torque based on brake pedaling of a driver; and a regenerative braking torque computation unit configured to compute a regenerative braking torque by restricting a response time of the regenerative braking torque to match a braking rate of a frictional brake based on a vehicle speed and the computed driver request braking torque, and compute the regenerative braking torque by releasing restriction on the response time of the regenerative braking torque in a case where the driver request braking torque decreases.