Vehicle Braking Control Device Motor Speed Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing braking control device for vehicles experiences discomfort due to abrupt changes in operation noise of the electric motor, which can lead to decreased controllability of fluid pressure inside the wheel cylinder when trying to suppress noise changes.
Innovation Solution
A braking control device that includes a fluid pressure control unit, a motor target calculation unit, and a difference calculation unit to adjust the rotation speed of the electric motor gradually, ensuring the fluid pressure inside the wheel cylinder is increased efficiently while minimizing noise discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the rotation speed of the electric motor is increased to increase the brake fluid discharge amount, then the fluid pressure inside the wheel cylinder increases, but the operation noise of the electric motor increases
Solution Approach 1:
The patent applies dynamics by making the motor speed target value adjustable and time-dependent. The control system dynamically modifies the motor speed target value based on the relationship between current and target fluid pressures, enabling the system to adapt motor speed characteristics to different operating conditions rather than using a fixed speed-pressure relationship
Solution Approach 2:
The patent changes the parameter of motor speed target value based on the pressure difference relationship. When the target fluid pressure is higher than current pressure, a larger motor speed target value is used for faster pressure increase. When target pressure equals or is lower than current pressure, a smaller motor speed target value is used to reduce noise, thus optimizing both performance and comfort
2Object-affected harmful factors
If an upper-limit is provided in the rotation speed of the electric motor to suppress abrupt noise changes, then the operation noise changes are suppressed, but the fluid pressure inside the wheel cylinder cannot be increased to the target value and controllability deteriorates
Solution Approach 1:
The patent makes the motor speed control dynamic by adjusting the motor speed target value based on real-time pressure conditions. The system dynamically selects between larger speed targets (when pressure needs to increase) and smaller speed targets (when pressure is sufficient or decreasing), thereby maintaining both noise comfort and pressure controllability under different operating conditions
Solution Approach 2:
The patent changes the motor speed target parameter according to the pressure relationship. By setting different motor speed target values based on whether target pressure is higher than or equal to current pressure, the system optimizes the balance between noise suppression and pressure control effectiveness
3Productivity
If the rotation speed of the electric motor is increased to increase the brake fluid discharge amount, then the fluid pressure inside the wheel cylinder increases faster, but the magnitude of operation noise changes largely
Solution Approach 1:
The patent applies dynamics by making the motor speed target value time-dependent and condition-adjustable. The control system dynamically modifies the motor speed target value based on the relationship between current and target fluid pressures, enabling the system to adapt motor speed characteristics to different operating conditions rather than using a fixed speed-pressure relationship
Solution Approach 2:
The patent changes the parameter of motor speed target value based on the pressure difference relationship. When the target fluid pressure is higher than current pressure, a larger motor speed target value is used for faster pressure increase. When target pressure equals or is lower than current pressure, a smaller motor speed target value is used to reduce noise, thus optimizing both performance and comfort
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
This configuration allows for faster fluid pressure increase inside the wheel cylinder while reducing abrupt noise changes, thus enhancing controllability and occupant comfort.
Implementation Method 1
an electric motor which is a power source of the pump
Implementation Method 2
a pump which supplies a brake fluid to the wheel cylinder
Data Source
AI summary
A control device including a fluid pressure control unit for controlling a pressure in a wheel cylinder by driving an electric motor of a pump on the basis of a command value; a motor target calculation unit for calculating a motor speed target value in accordance with an amount of increase in a fluid pressure target value; and a difference calculation unit for deriving a calculated value representing a difference obtained by subtracting the actual value from the target value for either the electric motor rotation speed or the pressure. The fluid pressure control unit derives the command value such that when the motor speed target value is less than the previous actual value for the electric motor rotation speed, the previous actual value is made the upper-limit of the command value, and the command value increases in proportion to the motor speed target value and to the calculated value.