Brake Pad Clearance and Thrust Control for Faster Brake Response
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Solution Overview
Problem
Existing brake control systems face challenges in achieving rapid braking response when shifting from a non-braking to a braking state, with issues related to control accuracy and response time, particularly due to insufficient sensor resolution and converging piston movement.
Innovation Solution
A brake control device and system that includes a command calculation unit with separate clearance and thrust command calculation units, integrating their values to generate an operation command for the piston, ensuring a high-response braking force is applied without deceleration near the pad contact position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the motor speed limit is set to be small when shifting from braking to non-braking, then operating noise is reduced and driver comfort is improved, but the movement time to clearance position increases and braking response is delayed
Solution Approach 1:
The patent applies dynamics by making the motor speed limit variable rather than fixed. The speed limit is dynamically adjusted based on the piston position relative to the clearance position. When the piston is far from clearance position, a higher speed limit is allowed for faster response. When approaching the clearance position, the speed limit is reduced to ensure precise positioning and prevent overshooting, thereby resolving the contradiction between response speed and positioning accuracy.
2Loss of time
If the motor speed limit is set to be large to improve braking response, then braking response time is reduced, but operating noise increases and driver comfort deteriorates
Solution Approach 1:
The patent applies local quality by implementing different speed limit strategies for different stages of piston movement. In the early stage when the piston is far from the clearance position, a high speed limit is applied to minimize response time. In the final stage when approaching the clearance position, a low speed limit is applied to reduce noise and ensure precise positioning. This localized differentiation of control parameters resolves the contradiction between response speed and noise reduction.
3Measurement precision
If sensor resolution is insufficient for detecting small piston movements near clearance position, then control accuracy deteriorates, but increasing sensor resolution increases system complexity and cost
Solution Approach 1:
The patent introduces an intermediary approach by using motor rotation position detection as a mediator to indirectly measure piston position. Instead of directly measuring the small piston displacement near the clearance position with a high-resolution position sensor, the system detects the motor's rotation position and converts it to piston position using the known mechanical relationship (lead screw pitch, gear ratios). This intermediary measurement method achieves high control accuracy without requiring complex high-resolution position sensors on the piston.
4Loss of time
If the piston moves quickly to the clearance position, then braking response is improved, but the piston may overshoot the clearance position causing instability and reduced control accuracy
Solution Approach 1:
The patent applies dynamics by implementing a dynamic speed limit that automatically adjusts based on the piston's proximity to the clearance position. The control system continuously monitors the piston position and reduces the speed limit as the piston approaches the target position. This dynamic adjustment allows the piston to move quickly when far from the target while automatically slowing down near the target, preventing overshooting and ensuring stable positioning without requiring complex control algorithms.
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 system enables shortened braking response times and improved control accuracy and safety by ensuring a desired thrust is generated quickly and efficiently when transitioning from non-braking to braking.
Implementation Method 1
a linear motion mechanism that converts the rotary motion of the electric motor into a linear motion and transmits the linear motion to the brake pad
Implementation Method 2
when the pedal is depressed, the braking force is controlled using a distortion sensor or the like after contact with the brake pad
Data Source
AI summary
An object of the present invention is to provide a brake control device and a brake system capable of braking with a shortened braking response when shifting from non-braking to braking. A brake control device 10 includes a command value calculation unit 4 that calculates an operation command value required to make a pressing force by which a brake pad 11a is pressed against a brake disc 11b reach a target thrust value. The command value calculation unit 4 includes: a clearance command calculation unit 43 that calculates a command value required for contact between the brake pad 11a and the brake disc 11b; and a thrust command calculation unit 40 that calculates a command value required for reaching the target thrust from a state where the brake pad 11a and the brake disc 11b are in contact with each other. When calculating the operation command value from a state where the brake pad 11a and the brake disc 11b are separated, the command value calculation unit 4 calculates the operation command value by integrating the command value calculated from the clearance command calculation unit 43 and the command value calculated from the thrust command calculation unit 40.