Smart Lock Operational End Stops for Motor Stall Prevention
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Solution Overview
Problem
Existing smart locks inefficiently manage power usage and mechanical wear due to repeated stalling against mechanical end stops, leading to battery instability and reduced motor life, as they lack effective methods to determine optimal stopping points beyond mechanical end stops.
Innovation Solution
A smart lock system that uses a processor to monitor current signals and position sensors to define operational end stops, preventing the electric actuator from stalling by stopping at predefined operational points before reaching mechanical end stops, thereby reducing unnecessary movement and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the motor is driven until the mechanical end stop is reached, then the lock mechanism reaches the locked or unlocked position, but the motor stalls causing excessive current draw (300%-400% of normal load), mechanical wear, and battery instability
Solution Approach 1:
The system performs preliminary detection of the mechanical end stop position using the position sensor before driving the motor to that position. By knowing where the end stop is located in advance, the control system can stop the motor at the optimal point just before the mechanical end stop is reached, preventing stalling and excessive current draw while still achieving complete locking or unlocking of the bolt.
Solution Approach 2:
The system uses feedback from the position sensor to continuously monitor the lock mechanism's position during motor actuation. This real-time feedback enables the control system to detect when the bolt has reached its fully locked or unlocked position and stop the motor at that precise moment, avoiding the mechanical end stop and the associated high current consumption and mechanical wear.
2Reliability
If the motor is driven repeatedly to stall at the mechanical end stop, then the lock mechanism achieves complete locking or unlocking, but significant gear wear and reduced motor life occur
Solution Approach 1:
The system performs preliminary detection of the mechanical end stop position using the position sensor before driving the motor to that position. By knowing where the end stop is located in advance, the control system can stop the motor at the optimal point just before the mechanical end stop is reached, preventing stalling and excessive current draw while still achieving complete locking or unlocking of the bolt.
Solution Approach 2:
The system uses feedback from the position sensor to continuously monitor the lock mechanism's position during motor actuation. This real-time feedback enables the control system to detect when the bolt has reached its fully locked or unlocked position and stop the motor at that precise moment, avoiding the mechanical end stop and the associated high current consumption and mechanical wear.
3Measurement precision
If the motor continues driving past the locked position, then the mechanical end stop is reached for verification, but operational time is wasted with no additional benefit
Solution Approach 1:
The system uses feedback from the position sensor to continuously monitor the lock mechanism's position during motor actuation. This real-time feedback enables the control system to detect when the bolt has reached its fully locked or unlocked position and stop the motor at that precise moment, avoiding the mechanical end stop and the associated high current consumption and mechanical wear.
Solution Approach 2:
The system replaces the mechanical end stop verification method with an electronic position sensor-based verification system. The position sensor provides precise electronic detection of the bolt's position, eliminating the need to mechanically drive the motor to the end stop for verification, thus reducing operational time while maintaining verification accuracy.
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
This approach reduces mechanical wear and power usage by accurately determining optimal stopping points, extending motor and battery life while improving operational efficiency and compatibility with various door mechanisms.
Implementation Method 1
a current sensor arranged to output a current signal indicative of an electrical current flowing through the electric actuator
Implementation Method 2
a position sensor arranged to output a location signal indicative of a position of the drive train
Data Source
AI summary
A smart lock for securing a closure is provided. The smart lock comprises: a drive train for actuating a lock mechanism between a first mechanical end stop and a second mechanical end stop, corresponding to an unlocked position and a locked position or vice-versa; an electric actuator arranged to drive the drive train to actuate the lock mechanism; a position sensor arranged to output a location signal indicative of a position of the drive train; a current sensor arranged to output a current signal indicative of an electrical current flowing through the electric actuator; and a processor. The processor is configured to: control the electric actuator to actuate the lock mechanism in a first direction; monitor the current signal; determine a position of the first mechanical end stop for the lock mechanism based upon the current signal; define a first operational end stop for the lock mechanism, the first operational end stop spaced from the first mechanical end stop; and control the electric actuator to actuate the lock mechanism to stop at the first operational end stop based upon the location signal.