L' accéléromètre à quartz et l'accéléromètre à faisceau vibrant à quartz partagent certaines similitudes dans leurs principes de fonctionnement, mais ils diffèrent fondamentalement par leur structure et leurs méthodes de mesure. Les deux sont basés sur des capteurs en quartz, mais leurs conceptions et leurs domaines d’application sont distincts.
Accéléromètre à quartz
As previously mentioned, the Quartz Accelerometer primarily utilizes the piezoelectric effect to measure acceleration. When a quartz crystal is subjected to acceleration or force, it undergoes a slight deformation, generating electric charge. These charge variations are used to measure the magnitude and direction of the acceleration.
Principe de fonctionnement de base :
- When an object accelerates, the internal structure, which includes a spring and a mass block, displaces. This displacement is sensed by the piezoelectric sensor attached to the quartz material. The charge response from the quartz crystal is converted into an acceleration signal.
- These signals are then processed and converted into usable outputs (usually voltage or current signals).
Quartz Vibrating Beam Accelerometer
The Quartz Vibrating Beam Accelerometer is designed based on the vibrating beam principle. It typically uses a quartz material vibrating beam (usually a small quartz beam) to sense acceleration. The frequency of the vibrating beam changes with acceleration, and this change can be detected by an electronic system.
The working principle is shown in Figure 1. The excitation circuit applies piezoelectric excitation to the quartz vibrating beam, causing it to undergo bending vibrations at its resonant frequency point. The mass block converts the external input acceleration into an axial force acting on the vibrating beam. By combining the force-frequency characteristics of the vibrating beam, the resonant frequency is altered by changing the stiffness of the beam. The frequency difference between the two vibrating beams is detected to obtain the magnitude and direction of the acceleration.
Principe de fonctionnement de base :
- Vibrating Beam: The accelerometer contains a fixed quartz beam that vibrates at a certain frequency. When acceleration is applied to the accelerometer, the motion of the beam alters its vibration frequency.
- Frequency Change: The vibration frequency of the beam is proportional to the applied acceleration. As acceleration changes, the deformation of the vibrating beam causes a change in its vibration frequency, which is detected and converted by the electronic circuit to calculate acceleration.
- Measurement Method: Quartz vibrating beam accelerometers typically offer high sensitivity and stability, making them suitable for high-precision acceleration measurements.
Key Differences:
| Fonctionnalité | Accéléromètre à quartz | Quartz Vibrating Beam Accelerometer |
|---|---|---|
| Principe de fonctionnement | Based on the piezoelectric effect of quartz crystals, detecting charge variation | Based on vibrating beam principle, detecting frequency changes |
| Sensing Element | Quartz crystal (utilizing piezoelectric effect) | Quartz beam (vibrating beam principle) |
| Output Signal | Charge variation (converted to electrical signal) | Frequency variation (converted to acceleration signal) |
| Application Field | Generally used for high-precision, low-frequency acceleration measurement | More suited for high-precision, broad dynamic range, and frequency-sensitive measurements |
| Stability | Excellent temperature stability and resistance to interference | Also highly stable, especially suitable for measuring small variations |
Summary:
- The Quartz Accelerometer primarily relies on the piezoelectric effect, sensing acceleration by measuring charge variations in the quartz crystal. It is suitable for general acceleration measurements, especially in low-frequency ranges.
- The Quartz Vibrating Beam Accelerometer, based on the vibrating beam principle, calculates acceleration by measuring the frequency changes in the quartz beam. It offers higher sensitivity and is ideal for applications requiring greater precision and a broad frequency response.
While they differ in principles, structure, and application, both rely on the unique properties of quartz materials to achieve high-precision acceleration measurement.
