Electric Brake Torque Estimation from Motor Position and Current
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Solution Overview
Problem
Existing electric brake devices require highly accurate sensors to estimate driving force, increasing costs and complicating control due to the need for wheel movement to acquire accurate force information.
Innovation Solution
An electric brake device comprising an electric motor, a straight-moving portion, a brake pad, and a motor control device that estimates braking torque based on motor position and current relationships, allowing for accurate control without high-precision sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If highly accurate sensors are used to acquire driving force information, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent extracts and eliminates the thrust sensor from the system by using alternative estimation methods. The control device estimates braking force through motor current detection and braking torque estimation, removing the need for expensive high-precision sensors while maintaining adequate measurement accuracy for control purposes
Solution Approach 2:
The patent replaces expensive high-precision sensors with lower-cost sensing approaches using standard motor current detectors and calculation-based estimation. This substitution uses more economical components that, while not as precise as thrust sensors, provide sufficient accuracy for the control application
2Measurement precision
If wheel movement is required to acquire accurate driving force information, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent substitutes mechanical measurement methods (requiring wheel movement and physical thrust sensors) with an electrical and computational approach. By detecting motor current and calculating braking torque through control algorithms, the system eliminates the need for complex mechanical movement and physical sensing infrastructure
Solution Approach 2:
The system uses its own existing components (motor current detector and control device) to generate the required force information. The motor control device leverages data already available from motor operation to estimate braking force, eliminating the need for separate measurement systems or additional mechanical actions
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 enables accurate and cost-effective control of the electric brake device, reducing the need for expensive sensors and simplifying the control process.
Implementation Method 1
an electric motor 8
Implementation Method 2
a brake pad 5a, 5b presses a disc rotor 2
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
It is an object of the present invention to provide an electric brake device capable of accurate control at low cost. The present invention includes a motor control device 11 that controls rotation of an electric motor 8 for pressing brake pads 5a, 5b. The motor control device 11 is provided with: a motor position-current relationship generation portion 43 that acquires a relationship between the rotational position and the current of the electric motor 8; a braking torque estimation portion 41 that estimates braking torque pressing the brake pads 5a, 5b, on the rotational position of the electric motor 8; and a braking torque-position relationship portion generation portion 42 that acquires a relationship between the rotational position and the braking torque of the electric motor 8 on the basis of information from the motor position-current relationship generation portion 43 and the braking torque estimation portion 41. The rotation of the electric motor 8 is controlled on the basis of information from the braking torque-position relationship portion generation portion 42.