Linear Actuator Tool Detection via Drive Motor Force Analysis
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Solution Overview
Problem
Existing linear actuators with removable tools face increased manufacturing costs and size due to the need for additional sensors to detect end-of-travel, which can lead to damage if not properly stopped.
Innovation Solution
An electronic module that acquires variables representing instantaneous force and its time derivative to control the interruption of drive means, reducing the need for additional sensors by determining when to stop the actuator based on predetermined values, and automatically restarting to return the component to its initial position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are added to detect end-of-travel position, then the actuator can stop properly to prevent damage, but manufacturing costs and device size increase
Solution Approach 1:
The actuator uses its own drive motor to generate the signal for end-of-travel detection. The motor's back-EMF or current characteristics naturally change when the movable component assembly reaches the end position, allowing the system to detect position without external sensors. The motor serves both its primary driving function and the secondary function of position sensing.
Solution Approach 2:
The drive motor is made multi-functional by using it both for actuation and for position detection. The electronic module analyzes electrical parameters (current, voltage, or back-EMF) from the motor to determine when the movable component assembly has reached the end position, eliminating the need for dedicated sensors while maintaining reliable detection.
2Reliability
If sensors are added to detect end-of-travel position, then the actuator can stop properly to prevent damage, but manufacturing costs increase
Solution Approach 1:
The actuator uses its own drive motor to generate the signal for end-of-travel detection. The motor's back-EMF or current characteristics naturally change when the movable component assembly reaches the end position, allowing the system to detect position without external sensors. The motor serves both its primary driving function and the secondary function of position sensing.
Solution Approach 2:
The sensing function is extracted from the motor's electrical characteristics rather than requiring separate physical sensors. By monitoring existing electrical parameters (current, voltage, or back-EMF) that already exist during motor operation, the system removes the need for additional sensor components and their associated manufacturing costs.
3Measurement precision
If the actuator continuously monitors force variables, then it can detect tool presence accurately, but energy consumption increases
Solution Approach 1:
Instead of continuous monitoring, the electronic module performs periodic measurements of force variables at specific intervals during operation. The system measures the variable, compares it to reference values, and only continues monitoring if the tool presence state is uncertain, reducing unnecessary energy consumption while maintaining detection accuracy.
Solution Approach 2:
The system performs preliminary measurements of force variables during the initial phase of operation to establish baseline values and determine tool presence before full operation begins. This preliminary detection phase allows the system to adjust its monitoring strategy accordingly, reducing energy consumption during normal operation when tool presence is already known.
Data Source
AI summary
The present disclosure relates to a linear actuator including drive means for driving a movable component assembly for actuating a tool controlled by an electronic module. In exemplary embodiments, the module comprises acquisition means for acquiring a quantity that is representative of the instantaneous force supplied by the drive means and/or the time derivative of this variable, and the electronic module is capable of controlling interruption means for interrupting the operation of the drive means if the variable does not exceed a first predetermined value during a first predetermined time period from the start of the driving of the movable component assembly, and/or if the derivative does not exceed a second predetermined value during the first predetermined time period from the start of the driving of the movable component assembly.