high accuracy and high precision Vibrating Gyro | Products | Silicon Sensing Systems Japan - MEMS ring rate gyro

Silicon Sensing's gyros are Vibrating Type.
"In the world there are mainly three types of gyros:"

A vibrating element (vibrating resonator) , when rotated, is subjected to Coriolis effect that causes secondary vibration orthogonal to the original vibrating direction. By sensing the secondary vibration, the rate of turn can be detected. For vibration excitation and detection the piezo-electric effect is often used, therefore vibrating gyros are often called "piezo", "ceramic", or "quartz" gyro, although in fact vibration and detection do NOT necessarily use the piezo effect. This type of gyro is suitable for mass production and almost free of maintenance. Drawback is, when it is used under external vibration, it cannot distinguish between secondary vibration and external vibration:( This is especially true for those using tuning fork or beam (often triangular) shaped vibrating element which has solid support to the base/case. Dampers around it will not solve the problem since dampers will affect rotational motion, making the gyro's response worse. Our CRS gyro has overcome this problem using a ring shaped element vibrating in squeeze oval motion up&down while the ring is suspended by spokes around it : External vibration will not cause the oval squeeze vibration mode, and lateral only suspension by spokes around it, enables the element be insusceptible of linear vibrations/shocks no matter how hard the CRS gyro is strap down to the base.

Spinning Mass Gyro, is the classical gyro, that has a mass spinning steadily with free movable axis (so called gimbal) When the gyro is tilted, Gyroscopic effect causes precession (motion orthogonal to the direction tilt sense) on the rotating mass axis, hence letting you know the angle moved. Because mechanical constraints cause numerous error factors, the idea came up such that fixing the axis with springs and the spring tension is proportional to the precession speed. By integrating the spring tension one would get the angle. Angular velocity (rate of turn) sensor, therefore, is rate-gyroscope. Nowadays most gyroscopes are actually rate-gyroscopes. Dry tuned gyro ( dynamically tuned gyro ) is a type of spinning mass gyro, which has been designed to cause very small mechanical constraints once the spinning speed reaches to specific speed Do not confuse with GyroCompass. GyroCompass is also a spinning mass gyro (usually big) , but its axis is made to rotate (and maintain ) same direction as that of the earth rotation all the time, hence giving you True North all the time: But gyroSCOPE (gyro) gives you info on relative change of angles. Sale of spinning mass gyro is always contingent to specific regular maintenance. Very fragile.

Optical Gyroscope: Let laser ray reflect around many times within the enclosure. If the enclosure rotates, the duration between the moment of laser emittance to eventual reception will be different. In an RLG (Ring Laser Gyro), the laser go-around is done by mirrors inside the enclosure. In a FOG (Fiber Optic Gyro), the laser go-around is done by a coil of optical-fiber. Laser emitter deteriorates with time. Also, the fiber has its life. Fragile.

Other Gyroscopes include gas rate gyro, etc. Gas rate gyro sprays gas onto heated wires. When there's rotation the spray is curved therefore there's change in the temperature of the wires. Numerous factors including fluid mechanics uncertainties are blocking the practical usage of gas rate-gyro, although it has been produced in several cases with enclosures bigger than that typical for vibrating gyros. Characteristics change with mounting position, due to convectional heat transfer.