Electromechanical Service Brake Control Without Force Sensors
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Solution Overview
Problem
Existing electromechanical service brakes require force sensors for determining brake pressure, which are space-consuming and expensive, and their operation is not cost-effective.
Innovation Solution
Determine and store a current profile of the force-displacement characteristic of the force-sensor-less electromechanical service brake during parking, using the total rotation angle of the electric motor shaft to calculate the required braking force without direct force measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force sensors are used to determine brake pressure, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical force sensors with an electrical measurement system. The electric motor's current consumption is measured and used to calculate braking force through a force-displacement characteristic curve, substituting direct mechanical force measurement with electrical parameter measurement and computational derivation.
Solution Approach 2:
The patent introduces a control unit that acts as an intermediary between the electric motor and the braking system. This control unit measures current consumption, determines the force-displacement characteristic, and calculates the actual braking force, serving as a mediator that eliminates the need for direct force sensors while maintaining measurement capability.
2Measurement precision
If force sensors are used to determine brake pressure, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive mechanical force sensors with a control unit that uses electrical current measurement and computational algorithms. This substitution significantly reduces manufacturing costs while maintaining the ability to accurately determine brake pressure through electrical parameters and force-displacement characteristic curves.
Solution Approach 2:
The patent employs a cost-effective approach by using standard electrical sensors (current measurement) and software-based calculations instead of expensive mechanical force sensors. The solution uses readily available components and computational methods that are more economical while achieving the same measurement objective.
3Loss of information
If the parking brake is actuated during parking, then the force-displacement characteristic can be determined, but the braking process is extended
Solution Approach 1:
The patent performs preliminary measurement of the force-displacement characteristic during the parking brake actuation phase. By utilizing this time period to gather necessary data for subsequent service brake operations, the system prepares the force-displacement characteristic curve in advance, enabling accurate braking force calculation during normal driving without requiring additional measurement time.
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
Enables reliable braking without force sensors, ensuring simple, safe, and cost-effective operation of electromechanical service brakes by utilizing the relationship between the total rotation angle of the electric motor shaft and the position of the friction elements.
Implementation Method 1
an element moved by an electric motor, for example a ball screw, is provided, which acts on movable friction elements of the brake in order to close the brake. The force supplied by the electric motor is converted into a movement of the friction elements of the brake
Implementation Method 2
an element moved by an electric motor, for example a ball screw
Implementation Method 3
a brake pad is pressed against a brake disk and in this way the brake pressure required to close the brake is generated
Data Source
AI summary
In a method for operating a force-sensor-less electromechanical service brake of a vehicle, a current profile of a force-displacement characteristic is determined and stored during a closing of a parking brake when the vehicle is being parked. The current profile of the force-displacement characteristic is used during a subsequent trip to set a required braking force on the electromechanical service brake.