Vehicle Control Apparatus for Regenerative Braking Torque Compensation
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Solution Overview
Problem
Conventional electric and hybrid vehicles face limitations in maintaining consistent braking force and deceleration feeling during regenerative braking, leading to abnormal braking sensations and driver anxiety.
Innovation Solution
A vehicle control apparatus that includes an inputter, determiner, calculator, and controller to receive and process regenerative braking and ABS signals, calculating a current pressure value corresponding to coast regeneration torque and compensating the target pressure value to maintain uniform deceleration and improve braking feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is performed by cooperative control of friction brake torque and electric motor brake torque, then fuel efficiency is improved, but braking force consistency deteriorates when ABS control starts
Solution Approach 1:
The controller calculates coast regeneration torque values in advance and stores them in a map structure before ABS control begins. When ABS control starts, the pre-calculated coast regeneration torque values are immediately applied, eliminating the delay and inconsistency that would occur if calculations were performed in real-time during ABS operation.
Solution Approach 2:
The system continuously monitors wheel speeds and braking conditions, using this feedback to select appropriate coast regeneration torque values from the pre-calculated map. The controller adjusts the electric motor brake torque based on feedback from wheel speed sensors and ABS control status, maintaining consistent total braking force throughout the braking process.
2Device complexity
If coast regeneration torque is not considered during braking, then control simplicity is maintained, but deviation between braking forces occurs
Solution Approach 1:
Coast regeneration torque values are pre-calculated and stored in a map during system initialization or before braking events. This preliminary preparation allows the controller to simply lookup and apply the appropriate coast regeneration torque value during braking without performing complex real-time calculations, maintaining control simplicity while achieving accurate braking force distribution.
3Loss of time
If predetermined torque values are used without considering coast regeneration torque, then response time is reduced, but deceleration feeling uniformity deteriorates
Solution Approach 1:
The coast regeneration torque map is pre-computed and stored, allowing the controller to immediately retrieve and apply the appropriate torque value when braking conditions match map criteria. This eliminates real-time calculation delays while ensuring accurate coast regeneration torque compensation, maintaining both fast response time and uniform deceleration feeling.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively compensates for the coast regeneration torque during ABS control, maintaining consistent braking force and improving the deceleration feeling, thereby reducing abnormal braking sensations and driver anxiety.
Implementation Method 1
a braking force according to a brake pedal pressure can be generated through frictional braking
Implementation Method 2
regenerative braking is performed by cooperative control of a friction brake torque and an electric motor brake torque to reduce a vehicle speed and charge a battery
Data Source
AI summary
The vehicle control apparatus include: an inputter receive a regenerative braking signal and an anti-lock brake system operation signal output, and a driver's current necessary braking pressure value, in a regenerative braking state and in an ABS started state, a determiner determines whether the input driver's current necessary braking pressure value is in a first state in which the driver's current necessary braking pressure value is less than or equal to a set target pressure value, a calculator configured to calculate a current pressure value corresponding to a coast regeneration torque value when the input driver's current necessary braking pressure value is in the first state and a controller to convert the calculated current pressure value into a ratio of the current pressure value to the driver's current necessary braking pressure value to compensate for the target pressure value, and transmit a compensated target pressure value to the braking apparatus.