MEMS Mirror Torsion Angle Sensing via Periodic Voltage Overlay
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Solution Overview
Problem
Existing MEMS apparatuses face challenges in accurately determining the torsion angle of a mirror body, which is crucial for adequate operation, especially in LIDAR scanning applications for autonomous vehicles.
Innovation Solution
The method involves applying a driver voltage to an electrostatic comb drive and overlaying it with a periodic voltage signal to determine the torsion angle of the mirror body based on the periodic voltage signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a driver voltage is applied to the electrostatic comb drive to control the mirror body torsion angle, then the mirror body can be deflected to the desired angle, but the actual torsion angle cannot be accurately determined
Solution Approach 1:
The patent applies feedback by overlaying a periodic voltage signal on the driver voltage and measuring the resulting current signal. The current signal provides feedback information about the actual torsion angle, allowing the system to determine the mirror body's actual position and ensure accurate operation.
Solution Approach 2:
The patent uses a periodic voltage signal as an intermediary to enable torsion angle measurement. By modulating the driver voltage with a periodic signal and measuring the resulting current, the system can indirectly determine the torsion angle without directly measuring the mechanical position.
2Measurement precision
If the torsion angle determination method is improved by overlaying periodic voltage signals, then measurement precision increases, but device complexity increases
Solution Approach 1:
The electrostatic comb drive serves multiple functions: it acts as both the actuator that generates torque to deflect the mirror body and the sensor that measures the torsion angle through current measurement. This multi-functionality reduces the need for separate measurement devices and simplifies the overall system.
Solution Approach 2:
The system uses its own driver voltage circuitry to perform both actuation and measurement functions. By overlaying a periodic voltage signal on the existing driver voltage and measuring the resulting current, the system performs self-diagnosis without requiring external measurement equipment.
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 allows for precise and accurate determination of the torsion angle, ensuring that the mirror body is deflected through the set angle, thereby enhancing the operational efficiency of MEMS apparatuses.
Implementation Method 1
one or more electrostatic comb drives for twisting the mirror body based on one or more driver voltages
Implementation Method 2
determining a torsion angle of a mirror body of the MEMS apparatus based on the periodic voltage signal
Data Source
AI summary
A method comprises applying a driver voltage to an electrostatic comb drive of an MEMS apparatus and overlaying the driver voltage with a periodic voltage signal. The method further comprises determining a torsion angle of a mirror body of the MEMS apparatus based on the periodic voltage signal.