Convertible Roof Locking State Detection via Motor Current Monitoring
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Solution Overview
Problem
Existing methods for determining the locking state of a motor-driven lock for convertible car covers are costly and complex due to the need for additional sensors and switches, which are difficult to install and lead to unnecessary expenses.
Innovation Solution
Monitoring the current consumption and temporal course of the motor, as well as engine power and voltage, to differentiate between a correctly locked and an air-locked state, utilizing existing internal operating parameters and pulse width modulation with a PID controller to maintain a constant motor voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors and switches are installed to monitor the locking state, then the locking state can be accurately detected, but the device complexity and installation cost increase significantly
Solution Approach 1:
The motor serves dual functions: both actuating the locking mechanism and providing feedback about its state through current consumption monitoring. The system monitors its own operational parameters (current, voltage, time) to determine locking status, eliminating the need for separate sensors and switches.
Solution Approach 2:
The patent replaces the mechanical/electrical sensing system (sensors, switches, wiring) with an electrical parameter monitoring system. By measuring current consumption, voltage, and time during motor operation, the system infers locking state without physical contact sensors, thereby reducing device complexity while maintaining detection accuracy.
2Reliability
If additional sensors are installed to prevent airlock, then the safety against incomplete locking is improved, but the installation cost and complexity increase
Solution Approach 1:
The system continuously monitors motor current consumption and voltage during the locking process, comparing actual values against expected profiles. This feedback mechanism enables real-time detection of abnormal conditions (such as airlock where the latch reaches position without proper engagement) and can trigger corrective actions or warnings, improving reliability without additional safety sensors.
Solution Approach 2:
The patent uses electrical parameters (current, voltage, time) as intermediary indicators to infer the mechanical locking state. Instead of directly sensing the mechanical engagement between latch and bolt, the system measures the electrical characteristics of the motor during operation, which indirectly but reliably indicate whether proper locking occurred, thereby preventing airlock conditions.
3Measurement precision
If multiple monitoring components are added, then the locking state can be verified, but the assembly effort and costs increase
Solution Approach 1:
The motor is designed to perform multiple functions: it provides the actuating force for the locking mechanism and simultaneously serves as the sensing element through its electrical characteristics. The control unit integrates both motor control and locking state monitoring functions, eliminating the need for separate monitoring components and reducing assembly complexity 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 assembly effort and costs by using existing components to accurately determine the locking state, distinguishing between a complete lock and air locking through significant differences in electricity requirements, thereby ensuring the roof is fully locked and safe to drive.
Implementation Method 1
recording and evaluating the current consumption of the motor driving the locking mechanism of the convertible top and/or its temporal profile
Data Source
Figure 1~2
AI summary
In a method for determining the locking state of a motor-driven locking mechanism for the convertible top, electrical operating parameters of the motor driving the locking mechanism of the convertible top and/or its peripheral devices are recorded and evaluated.