Eccentric Motor Tilt Sensing via Current Synchronous Component
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Solution Overview
Problem
Existing tilt sensors are costly, inaccurate, and bulky, making them unsuitable for certain applications, such as consumer electronics and industrial use, where precise tilt angle measurement is required without occupying valuable space.
Innovation Solution
A tilt sensor apparatus that senses the current flowing in an eccentric mass motor and uses a detector circuit to assess the amplitude of the synchronous component of the motor current, providing an output signal indicating the tilt angle relative to a gravitational axis, employing synchronous demodulation, filtering, and processing to accurately estimate the tilt angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional tilt sensors (accelerometers, magnetic devices, pendulum systems) are used, then tilt angle measurement is achieved, but cost increases, accuracy decreases, and device size increases
Solution Approach 1:
The patent makes the eccentric mass motor serve dual functions: providing vibratory motion to the device and simultaneously acting as a tilt sensor. By measuring the motor current drawn by the eccentric mass motor, the system determines tilt angle without requiring separate sensor components, thereby reducing device complexity and cost while maintaining measurement capability
Solution Approach 2:
The system uses the motor's own operational parameter (current consumption) as the sensing mechanism. The eccentric mass motor inherently draws varying current based on its tilt angle due to gravitational effects on the eccentric mass, and this self-generated signal is processed to determine tilt angle, eliminating the need for external sensing components
2Measurement precision
If separate tilt sensors are added to provide accurate tilt measurement, then measurement precision improves, but device size and space consumption increase
Solution Approach 1:
The eccentric mass motor is designed to perform both its primary function of generating vibratory motion and a secondary function of tilt sensing. The motor controller processes the motor current signal to extract tilt angle information, allowing one component to fulfill multiple roles and eliminating the need for additional sensor space on the circuit board
Solution Approach 2:
The patent combines the tilt sensing function with the existing motor assembly by measuring the motor current. The motor controller integrates both motor drive and tilt sensing capabilities, merging what would traditionally be separate components (motor + tilt sensor) into a single integrated system that saves space
3Measurement precision
If high-precision tilt sensors are used, then tilt angle measurement accuracy improves, but device cost increases
Solution Approach 1:
The system utilizes the motor's inherent electrical characteristics (current draw variations due to gravitational load on the eccentric mass) as the sensing mechanism. This self-service approach converts an existing operational parameter into a useful sensing signal, eliminating the need to purchase and integrate expensive dedicated tilt sensors while maintaining measurement accuracy
Solution Approach 2:
The motor controller acts as an intermediary that processes the motor current signal to extract tilt angle information. Rather than using expensive dedicated sensors, the system uses the controller's existing signal processing capabilities to interpret the motor current variations caused by tilt, providing accurate measurement at lower cost
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 solution provides a cost-effective, compact, and accurate method for determining tilt angles, suitable for various applications, including consumer electronics and industrial use, by leveraging the motor current's synchronous component to estimate the tilt angle with high precision.
Implementation Method 1
a rotor that supports an eccentric mass and rotates about a rotor axis
Implementation Method 2
the amplitude of a synchronous component of the motor current varies with a tilt angle of the rotor axis relative to a gravitational axis
Data Source
Figure 1~3
Figure 2
Figure 4~5
AI summary
In described examples, for sensing or estimating a tilt angle, a current (Im) flowing in an eccentric mass motor (110) is sensed, and a detector circuit (180) assesses the amplitude of a synchronous component of the motor current and provides an output signal or value (190) indicating a tilt angle (θy) relative to a gravitational axis (G) at least partially according to the amplitude of the synchronous component of the motor current (Im).