Actuator Force Estimation Using Motor Current Signals
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Solution Overview
Problem
Existing position-based control methods for actuators in vehicles fail to detect and prevent excessive actuating forces, which can cause damage to actuators or other elements due to tooth-on-tooth contact and excessive synchronizing force requirements.
Innovation Solution
A method to determine actuating force by evaluating current intensity signals, using a control device to monitor and limit electrical current consumption based on the relationship between the position of a transmission element and the actuating force, allowing for path-dependent control and regulation of electric motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If position-based control is used for actuator control, then the control system is simple and easy to implement, but the actuating force cannot be detected or limited, creating risk of damage due to excessive force
Solution Approach 1:
The patent replaces direct mechanical force measurement with an electrical measurement approach. By measuring the electrical current consumed by the electric motor and using the known relationship between current and actuating force (based on motor characteristics and gear ratio), the system determines actuating force without complex mechanical sensors. This substitution maintains control simplicity while enabling force detection and limitation for reliable operation.
2Reliability
If electrical current measurement is used to determine actuating force, then reliable detection and limitation of excessive force is achieved, but the system complexity increases due to additional monitoring and control requirements
Solution Approach 1:
The patent utilizes the electrical current signal that already exists in the actuator system for motor operation. This same current signal is evaluated to determine actuating force, making the measurement system self-service rather than requiring separate dedicated sensors or measurement devices. The control unit leverages existing electrical infrastructure to achieve force detection and limitation, minimizing additional system complexity.
3Reliability
If the actuating force is limited by limiting electrical current, then damage prevention is achieved quickly, but the power output of the actuator is reduced
Solution Approach 1:
The patent implements dynamic current limitation rather than a fixed reduction. The control unit monitors the evaluated actuating force in real-time and adjusts the electrical current dynamically based on the actual operating conditions and detected force levels. This dynamic approach allows the actuator to maintain full power output when operating within safe parameters while quickly limiting current only when excessive force is detected, thus preventing damage without unnecessarily reducing overall power capability.
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 detection and prevention of excessive actuating forces, preventing damage by quickly limiting actuating forces to permissible levels, particularly effective in electrically actuated systems with minimal inertia.
Implementation Method 1
the control actuator is designed to generate the actuating force by absorbing electrical current, in particular by means of an electric motor
Implementation Method 2
the mechanical power output of the actuator, and in particular of the electric motor, is proportional to the electrical power consumption, which is determined in particular by the basic formula
Data Source
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AI summary
What is disclosed is a method for determining an actuation force (FB) of an actuator (A), wherein the actuator (A) is designed to generate the actuation force (FB) by receiving electric current (I), in particular by way of an electric motor, and to transmit said actuation force to at least one further element, and wherein the actuation force (FB) is determined by evaluating a current strength signal (Si) that describes the magnitude of the current strength of the received electric current (I). A control device (3), a system, a computer program product and a data carrier are also disclosed.