After the war, gyroscopes were miniaturized for use in guided missiles and weapons navigation systems; these midget gyroscopes weighed less than 3 ounces 85 g and had a diameter of approximately 1 inch 2. The gyroscope is basically a massive rotor that is fixed in light supporting rings called gimbals. The gimbals have frictionless bearings that isolate the central rotor from outside torques. The spin axis is defined by the axle of the spinning wheel. The rotor spins about an axis, with three degrees of rotational freedom.
Having thus acquired extraordinary stability of balance at high speeds, it maintains the high speed rotation axis of its central rotor. Now when the gyroscope is applied with external torques or rotations about the given axis, one can measure the orientation using a precession phenomenon precession refers to the change in the orientation of the rotational axis of a rotating body. In other words, upon the application of external torque - along a direction perpendicular to the rotational axis - on an object rotating about an axis, precession takes place.
This rotation about the spin axis is identified and information on this rotation is passed on to a motor or other device that applies torque in an opposite direction thus cancelling the precession and maintaining the orientation. Precession can also be avoided by using two gyroscopes arranged perpendicular to each other. The rotation rate can be measured by the pulsation of counteracting torque at constant time intervals.
MEMS gyroscopes are basically miniaturized gyroscopes found in electronic devices. These are built on the idea of the Foucault pendulum and use a vibrating element. Also known as a wine-glass gyroscope or mushroom gyro, the HRG makes use of a thin solid-state hemispherical shell, anchored by a thick stem.
This shell is driven to a flexural resonance by electrostatic forces generated by electrodes which are deposited directly onto separate fused-quartz structures enveloping the shell.
The inertial property of the flexural standing waves helps produce a gyroscopic effect. Also known as a Coriolis Vibratory Gyroscope CVG , a vibrating structure gyroscope is a gyroscope that uses a vibrating structure to determine the rate of rotation. A DTG is a rotor suspended by a universal joint with flexure pivots.
The flexure spring stiffness is independent of spin rate. But the dynamic inertia from the gyroscopic reaction effect from the gimbal lends a negative spring stiffness proportional to the square of the spin speed.
So at a particular speed, the two moments cancel each other, freeing the rotor from torque, making it an ideal gyroscope. A ring laser gyroscope uses the Sagnac effect to calculate rotation by measuring the shifting interference pattern of a beam split into two-halves, even as the two-halves move around the ring in opposite directions.
In the Sagnac effect, a beam of light is split and the two beams are made to follow the same path but in opposite directions.
On return to the point of entry the two light beams are allowed to exit the ring and undergo interference. A fiber optic gyroscope uses the interference of light to detect mechanical rotation. How a gyroscope works in a ship. Browse Search Menu. Browse Browse posts by categories. Development tools. Editors Ariel Hershkovitz. Sensor fusion.
Posted On November 29, Charles Pao. Thursday, November 29, In an earlier post, we defined a piece of technology that is helping to shape the future— the IMU sensor. Uses: Inertial navigation systems in military aircraft, commercial airliners, ships and spacecrafts Pros: High performance: High accuracy, better than 0. Posted By. Sensor fusion Wireless. August 10, Automotive Sensor fusion Wireless.
June 22, May 30, Sensors, sensors everywhere. Now what do I do? Posted On July 25, Moshe Sheier. Posted On March 17, Elia Shenberger. It continues trying to move leftward because of Newton's first law of motion, but the gyro's spinning rotates it, like this:.
This effect is the cause of precession. The different sections of the gyroscope receive forces at one point but then rotate to new positions! When the section at the top of the gyro rotates 90 degrees to the side, it continues in its desire to move to the left. The same holds true for the section at the bottom -- it rotates 90 degrees to the side and it continues in its desire to move to the right. These forces rotate the wheel in the precession direction.
As the identified points continue to rotate 90 more degrees, their original motions are cancelled. So the gyroscope's axle hangs in the air and precesses. When you look at it this way you can see that precession isn't mysterious at all -- it is totally in keeping with the laws of physics!
The effect of all this is that, once you spin a gyroscope, its axle wants to keep pointing in the same direction. If you mount the gyroscope in a set of gimbals so that it can continue pointing in the same direction, it will. This is the basis of the gyro-compass.
If you mount two gyroscopes with their axles at right angles to one another on a platform, and place the platform inside a set of gimbals, the platform will remain completely rigid as the gimbals rotate in any way they please. This is this basis of inertial navigation systems INS. In an INS, sensors on the gimbals' axles detect when the platform rotates.
The INS uses those signals to understand the vehicle's rotations relative to the platform. If you add to the platform a set of three sensitive accelerometers , you can tell exactly where the vehicle is heading and how its motion is changing in all three directions. With this information, an airplane's autopilot can keep the plane on course, and a rocket's guidance system can insert the rocket into a desired orbit! Sign up for our Newsletter! Mobile Newsletter banner close.
Mobile Newsletter chat close.
0コメント