LRA Drive Control with Phase Tracking for Resonant Drift
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Solution Overview
Problem
Linear Resonant Actuators (LRAs) experience degraded performance due to large Q values and frequency deviations caused by climate, humidity, and aging, which existing technologies fail to effectively address.
Innovation Solution
An electronic device comprising a signal generator, driver, delay unit, sensor, and Digital Signal Processor (DSP) that generates and adjusts digital signals to control the resonant frequency and gain of the LRA, using phase difference and temperature measurements to maintain optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the LRA operates at its central resonant frequency, then the vibration feedback performance is optimized, but the operational performance degrades when the frequency deviates due to climate, humidity, and aging
Solution Approach 1:
The patent implements a feedback control system where the DSP continuously monitors the phase difference between the drive signal and the back electromotive force (EMF) signal from the LRA. Based on this phase difference information, the system automatically adjusts the resonant frequency of the signal generator to maintain optimal operation. This closed-loop feedback mechanism enables the system to adapt to frequency drift caused by environmental factors and aging, resolving the contradiction between maintaining optimal performance and adapting to frequency variations.
Solution Approach 2:
The patent dynamically changes the resonant frequency parameter of the signal generator based on detected phase difference. The DSP adjusts the frequency parameter in real-time to track the actual resonant frequency of the LRA, which shifts due to climate, humidity, and aging. This parameter adaptation allows the system to maintain optimal vibration feedback performance despite environmental variations and component aging.
2Device complexity
If a fixed resonant frequency is used, then the device complexity is reduced, but the performance degrades due to frequency drift from environmental factors
Solution Approach 1:
The patent employs a feedback mechanism where the phase difference between the drive signal and LRA response is continuously measured and used to adjust the resonant frequency. This feedback approach maintains performance consistency without requiring overly complex control systems, as it uses simple phase detection and frequency adjustment logic implemented in the DSP.
Solution Approach 2:
The system performs self-adjustment by automatically detecting phase difference and correcting its own resonant frequency without external intervention. The DSP monitors the LRA's actual resonant frequency through phase measurement and autonomously adjusts the signal generator to maintain optimal operation, enabling the system to self-correct for environmental drift and aging effects.
3Reliability
If the resonant frequency is continuously adjusted to track environmental changes, then the performance is maintained, but the measurement and control complexity increases
Solution Approach 1:
The patent uses phase difference as a feedback parameter to indicate deviations from optimal resonant frequency. By monitoring this single phase parameter, the system can determine when and how much to adjust the frequency without requiring complex measurements of multiple environmental parameters directly. This simplifies the detection and measurement complexity while maintaining reliable performance.
Solution Approach 2:
The phase difference measurement serves multiple functions: it indicates frequency deviation, guides frequency adjustment, and provides a unified metric for both detection and control. This multi-functional use of a single measurement parameter reduces overall system complexity compared to implementing separate sensors for temperature, humidity, and direct frequency measurement.
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
The solution stabilizes the resonant frequency and gain of the LRA, enhancing its operational performance and making it less susceptible to environmental variations, thus improving the overall performance and reliability of the device.
Implementation Method 1
An LRA (Linear Resonant Actuator) can provide vibration feedback for a user
Implementation Method 2
The delay unit delays the digital signal for a predetermined time, so as to generate an estimated voltage signal
Implementation Method 3
The sensor detects the current flowing through the LRA, so as to generate a sensing current signal
Implementation Method 4
The DSP controls the resonant frequency or the gain value of the signal generator according to the estimated voltage signal and the sensing current signal
Data Source
AI summary
An electronic device for controlling an LRA (Linear Resonant Actuator) includes a signal generator, a driver, a delay unit, a sensor, and a DSP (Digital Signal Processor). The signal generator generates a digital signal. The driver drives the LRA according to the digital signal. The delay unit delays the digital signal for a predetermined time, so as to generate an estimated voltage signal. The sensor detects the current flowing through the LRA, so as to generate a sensing current signal. The DSP controls the resonant frequency or the gain value of the signal generator according to the estimated voltage signal and the sensing current signal.