TheInfoList

A gyroscope (from
Ancient Greek Ancient Greek includes the forms of the Greek language Greek ( el, label=Modern Greek Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply as Greek (, ), refers collectively to the diale ...
γῦρος ''gûros'', "circle" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining
orientation Orientation may refer to: Positioning in physical space * Map orientation, the relationship between directions on a map and compass directions * Orientation (housing), the position of a building with respect to the sun, a concept in building design ...
and
angular velocity In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force. ...

. It is a spinning wheel or disc in which the axis of rotation (spin axis) is free to assume any orientation by itself. When rotating, the orientation of this axis is unaffected by tilting or rotation of the mounting, according to the
conservation of angular momentum In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force. " ...
. Gyroscopes based on other operating principles also exist, such as the microchip-packaged MEMS gyroscopes found in electronic devices (sometimes called gyrometers), solid-state
ring lasersRing lasers are composed of two beams of light Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that can be visual perception, perceived by the human eye. Visible light is usually defined as ...
,
fibre optic gyroscope A fibre-optic gyroscope (FOG) senses changes in orientation using the Sagnac effect, thus performing the function of a mechanical gyroscope A gyroscope (from Ancient Greek γῦρος ''gûros'', "circle" and σκοπέω ''skopéō'', "to l ...
s, and the extremely sensitive
quantum gyroscope A quantum gyroscope is a very sensitive device to measure Angular momentum, angular rotation based on quantum mechanics, quantum mechanical principles. The first of these has been built by Richard Packard and his colleagues at the University of Ca ...
. Applications of gyroscopes include
inertial navigation system An inertial navigation system (INS) is a navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation ...
s, such as in the
Hubble Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...
, or inside the steel hull of a submerged submarine. Due to their precision, gyroscopes are also used in
gyrotheodolite In surveying Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial or three-dimensional positions of points and the distances and angles between them. A land surveying professional is called a ...
s to maintain direction in tunnel mining. Gyroscopes can be used to construct
gyrocompass A gyrocompass is a type of non-magnetic compass A compass is a device that shows the cardinal direction The four cardinal directions, or cardinal points, are the directions north, east, south, and west, commonly denoted by their initi ...
es, which complement or replace magnetic compasses (in ships, aircraft and spacecraft, vehicles in general), to assist in stability (bicycles, motorcycles, and ships) or be used as part of an inertial guidance system. MEMS gyroscopes are popular in some consumer electronics, such as smartphones.

# Description and diagram

A gyroscope is an instrument, consisting of a wheel mounted into two or three
gimbal A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of ...

s providing pivoted supports, for allowing the wheel to rotate about a single axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow a wheel mounted on the innermost gimbal to have an orientation remaining independent of the orientation, in space, of its support. In the case of a gyroscope with two gimbals, the outer gimbal, which is the gyroscope frame, is mounted so as to pivot about an axis in its own plane determined by the support. This outer gimbal possesses one degree of rotational freedom and its axis possesses none. The second gimbal, inner gimbal, is mounted in the gyroscope frame (outer gimbal) so as to pivot about an axis in its own plane that is always perpendicular to the pivotal axis of the gyroscope frame (outer gimbal). This inner gimbal has two degrees of rotational freedom. The axle of the spinning wheel defines the spin axis. The rotor is constrained to spin about an axis, which is always perpendicular to the axis of the inner gimbal. So the rotor possesses three degrees of rotational freedom and its axis possesses two. The wheel responds to a force applied to the input axis by a reaction force to the output axis. The behaviour of a gyroscope can be most easily appreciated by consideration of the front wheel of a bicycle. If the wheel is leaned away from the vertical so that the top of the wheel moves to the left, the forward rim of the wheel also turns to the left. In other words, rotation on one axis of the turning wheel produces rotation of the third axis. A gyroscope flywheel will roll or resist about the output axis depending upon whether the output gimbals are of a free or fixed configuration. Examples of some free-output-gimbal devices would be the attitude reference gyroscopes used to sense or measure the pitch, roll and yaw attitude angles in a spacecraft or aircraft. The centre of gravity of the rotor can be in a fixed position. The rotor simultaneously spins about one axis and is capable of oscillating about the two other axes, and it is free to turn in any direction about the fixed point (except for its inherent resistance caused by rotor spin). Some gyroscopes have mechanical equivalents substituted for one or more of the elements. For example, the spinning rotor may be suspended in a fluid, instead of being mounted in gimbals. A
control moment gyroscope A control moment gyroscope (CMG) is an attitude control Attitude control is the process of controlling the orientation of an aerospace Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is ve ...
(CMG) is an example of a fixed-output-gimbal device that is used on spacecraft to hold or maintain a desired attitude angle or pointing direction using the gyroscopic resistance force. In some special cases, the outer gimbal (or its equivalent) may be omitted so that the rotor has only two degrees of freedom. In other cases, the centre of gravity of the rotor may be offset from the axis of oscillation, and thus the centre of gravity of the rotor and the centre of suspension of the rotor may not coincide.

# History

Essentially, a gyroscope is a
top A spinning top, or simply a top, is a toy A toy is an item that is used primarily by children though may also be marketed to adults under certain circumstances. Playing with toys can be an enjoyable means of training young children for li ...

combined with a pair of
gimbal A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of ...

s. Tops were invented in many different civilizations, including classical Greece, Rome, and China. Most of these were not utilized as instruments. The first known apparatus similar to a gyroscope (the "Whirling Speculum" or "Serson's Speculum") was invented by
John SersonJohn Serson (died 1744) was an English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon England, early medieval England, which has eventually ...
in 1743. It was used as a level, to locate the horizon in foggy or misty conditions. The first instrument used more like an actual gyroscope was made by
Johann Bohnenberger Johann Gottlieb Friedrich von Bohnenberger (5 June 1765 – 19 April 1831) was a German astronomer born at Simmozheim, Duchy of Württemberg, Württemberg. He studied at the University of Tübingen. In 1798, he was appointed professor o ...
of Germany, who first wrote about it in 1817. At first he called it the "Machine". Bohnenberger's machine was based on a rotating massive sphere. In 1832, American Walter R. Johnson developed a similar device that was based on a rotating disc. The French mathematician
Pierre-Simon Laplace Pierre-Simon, marquis de Laplace (; ; 23 March 1749 – 5 March 1827) was a French scholar A scholar is a person who pursues academic and intellectual activities, particularly those that develop expertise in an area of Studying, study. A ...

, working at the
École Polytechnique File:Statue X DSC08329.JPG, upA statue in the courtyard of the school commemorates the cadets of ''Polytechnique'' rushing to the Battle of Paris (1814), defence of Paris in 1814. A copy was installed in West Point. The École Polytechnique (Fr ...
in Paris, recommended the machine for use as a teaching aid, and thus it came to the attention of
Léon Foucault Jean Bernard Léon Foucault ( , , ; 18 September 1819 – 11 February 1868) was a French physicist A physicist is a scientist A scientist is a person who conducts Scientific method, scientific research to advance knowledge in an Branches of ...
. In 1852, Foucault used it in an experiment involving the rotation of the Earth. It was Foucault who gave the device its modern name, in an experiment to see (Greek ''skopeein'', to see) the Earth's rotation (Greek ''gyros'', circle or rotation), which was visible in the 8 to 10 minutes before friction slowed the spinning rotor. In the 1860s, the advent of electric motors made it possible for a gyroscope to spin indefinitely; this led to the first prototype
heading indicator The heading indicator (also called an HI) is a flight instrument used in an aircraft An aircraft is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using eithe ...

s, and a rather more complicated device, the
gyrocompass A gyrocompass is a type of non-magnetic compass A compass is a device that shows the cardinal direction The four cardinal directions, or cardinal points, are the directions north, east, south, and west, commonly denoted by their initi ...
. The first functional gyrocompass was patented in 1904 by German inventor . American
Elmer Sperry Elmer Ambrose Sperry Sr. (October 12, 1860 – June 16, 1930) was an American inventor and entrepreneur, most famous for construction, 2 years after Herman Anschütz-Kaempfe, of the gyrocompass and as founder of the Sperry Gyroscope Company. H ...
followed with his own design later that year, and other nations soon realized the military importance of the invention—in an age in which naval prowess was the most significant measure of military power—and created their own gyroscope industries. The
Sperry Gyroscope Company Sperry Corporation (1910−1986) was a major American equipment and electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. I ...
quickly expanded to provide aircraft and naval stabilizers as well, and other gyroscope developers followed suit. In 1917, the Chandler Company of Indianapolis created the "Chandler gyroscope", a toy gyroscope with a pull string and pedestal. Chandler continued to produce the toy until the company was purchased by TEDCO inc. in 1982. The chandler toy is still produced by TEDCO today. In the first several decades of the 20th century, other inventors attempted (unsuccessfully) to use gyroscopes as the basis for early
black box In science, computing, and engineering, a black box is a system which can be viewed in terms of its inputs and outputs (or transfer characteristics), without any knowledge of its internal workings. Its implementation is "opaque" (black). The ter ...
navigational systems by creating a stable platform from which accurate acceleration measurements could be performed (in order to bypass the need for star sightings to calculate position). Similar principles were later employed in the development of
inertial navigation system An inertial navigation system (INS) is a navigation Navigation is a field of study that focuses on the process of monitoring and controlling the movement of a craft or vehicle from one place to another.Bowditch, 2003:799. The field of navigation ...
s for
ballistic missile A ballistic missile follows a ballistic trajectory to deliver one or more warheads on a predetermined target. These weapons are guided only during relatively brief periods—most of the flight is unpowered. Short-range ballistic missiles stay ...
s. During World War II, the gyroscope became the prime component for aircraft and anti-aircraft gun sights. After the war, the race to miniaturize gyroscopes for guided missiles and weapons navigation systems resulted in the development and manufacturing of so-called midget gyroscopes that weighed less than and had a diameter of approximately . Some of these miniaturized gyroscopes could reach a speed of 24,000 revolutions per minute in less than 10 seconds. Gyroscopes continue to be an engineering challenge. For example, the axle bearings have to be extremely accurate. A small amount of friction is deliberately introduced to the bearings, since otherwise an accuracy of better than $10^$ of an inch (2.5 nm) would be required. Three-axis MEMS-based gyroscopes are also being used in portable electronic devices such as tablets,
smartphone A smartphone is a portable device A mobile device (or handheld computer) is a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can per ...

s, and
smartwatch A smartwatch is a wearable computer A wearable computer, also known as a wearable or body-borne computer, is a computing device worn on the body. The definition of 'wearable computer' may be narrow or broad, extending to smartphone A sma ...

es. This adds to the 3-axis acceleration sensing ability available on previous generations of devices. Together these sensors provide 6 component motion sensing; accelerometers for X,Y, and Z movement, and gyroscopes for measuring the extent and rate of rotation in space (roll, pitch and yaw). Some devices additionally incorporate a
magnetometer A magnetometer is a device that measures magnetic field A magnetic field is a vector field In vector calculus and physics, a vector field is an assignment of a vector to each point in a subset of space. For instance, a vector field in ...
to provide absolute angular measurements relative to the Earth's magnetic field. Newer MEMS-based inertial measurement units incorporate up to all nine axes of sensing in a single integrated circuit package, providing inexpensive and widely available motion sensing.

# Gyroscopic principles

All spinning objects have gyroscopic properties. The main properties that an object can experience in any gyroscopic motion are rigidity in space and
precession Precession is a change in the orientation Orientation may refer to: Positioning in physical space * Map orientation, the relationship between directions on a map and compass directions * Orientation (housing), the position of a building with re ...

.

## Rigidity in space

Rigidity in space describes the principle that a gyroscope remains in the fixed position on the plane in which it is spinning, unaffected by the Earth's rotation. For example, a bike wheel.

## Precession

A simple case of precession, also known as steady precession, can be described by the following relation to Moment: $\sum M_x = -I^2 \sin\theta \cos\theta +I_z\phi\text{'} \sin\theta\left(\phi\text{'} \cos\theta + \psi\text{'} \right)$ where $\phi\text{'}$ represents precession, $\psi\text{'}$ is represented by spin, $\theta$ is the nutation angle, and $I$ represents inertia along its respective axis. This relation is only valid with the Moment along the Y and Z axises are equal to 0. The equation can be further reduced noting that the angular velocity along the z-axis is equal to the sum of the Precession and the Spin: $\omega_z = \phi\text{'} \cos \theta + \psi\text{'}$, Where $\omega_z$ represents the angular velocity along the z axis. $\sum M_x = -I^2 \sin \theta \cos \theta + I_z \psi\text{'} \left(\sin\theta\right)\omega_z$ or $\sum M_x = \psi\text{'} \sin \theta \left(I_z\omega_z-I\psi\text{'} \cos \theta\right)$ Gyroscopic
precession Precession is a change in the orientation Orientation may refer to: Positioning in physical space * Map orientation, the relationship between directions on a map and compass directions * Orientation (housing), the position of a building with re ...

is torque induced. Described as the rate of change of the angular momentum and angular velocity that was produced by the same applied torque. This physical phenomenon results in the seemingly impossible dynamic occurrences. For example, a
spinning top A spinning top, or simply a top, is a toy with a squat body and a sharp point at the bottom, designed to be rotation, spun on its vertical Axis of rotation, axis, balancing on the tip due to the gyroscopic effect. Once set in motion, a top wil ...
. This gyroscopic process is taken advantage of in many aerospace circumstances, such as airplanes and helicopters to help guide them into a desired orientation.

# Contemporary uses

A
Steadicam Steadicam is a brand of camera stabilizer A camera stabilizer, or camera–stabilizing mount, is a device designed to hold a camera A camera is an optical instrument used to capture an image An SAR radar imaging, radar image ...
rig was employed during the filming of ''
Return of the Jedi ''Return of the Jedi'' (also known as ''Star Wars: Episode VI – Return of the Jedi'' is a 1983 American epic Epic commonly refers to: * Epic poetry, a long narrative poem celebrating heroic deeds and events significant to a culture or nati ...
'', in conjunction with two gyroscopes for extra stabilization, to film the background plates for the
speeder bikeSpeeder bikes (also known as "jumpspeeders" or "hover bikes") and swoop bikes (or just "swoops") are small, fast transports that use repulsorlift engines in the fictional ''Star Wars'' universe. ''Return of the Jedi'' includes a prominent speeder b ...
Garrett Brown Garrett Brown (born April 6, 1942) is an American inventor, best known as the creator of the Steadicam. Brown's invention allows camera operators to film while walking without the normal shaking and jostles of a handheld camera. The Steadicam was ...

operated the shot, walking through a redwood forest, running the camera at one frame per second. When projected at 24 frames per second, it gave the impression of flying through the air at perilous speeds.''Empire of Dreams: The Story of the Star Wars Trilogy'' Star Wars Trilogy Box Set DVD documentary,
004 004, 0O4, O04, OO4 may refer to: * 004, fictional British 00 Agent * 0O4, Corning Municipal Airport (California) * O04, the Oversea-Chinese Banking Corporation * Abdul Haq Wasiq, Guantanamo detainee 004 * Junkers Jumo 004 turbojet engine * Lauda Ai ...
/ref>

The heading indicator or directional gyro has an axis of rotation that is set horizontally, pointing north. Unlike a magnetic compass, it does not seek north. When being used in an airliner, for example, it will slowly drift away from north and will need to be reoriented periodically, using a magnetic compass as a reference.

## Gyrocompass

Unlike a directional gyro or heading indicator, a gyrocompass seeks north. It detects the rotation of the Earth about its axis and seeks the ''true'' north, rather than the ''magnetic'' north. Gyrocompasses usually have built-in damping to prevent overshoot when re-calibrating from sudden movement.

## Accelerometer

By determining an object's acceleration and integrating over time, the velocity of the object can be calculated. Integrating again, position can be determined. The simplest accelerometer is a weight that is free to move horizontally, which is attached to a spring and a device to measure the tension in the spring. This can be improved by introducing a counteracting force to push the weight back and to measure the force needed to prevent the weight from moving. A more complicated design consists of a gyroscope with a weight on one of the axes. The device will react to the force generated by the weight when it is accelerated, by integrating that force to produce a velocity.

# Variations

## Gyrostat

A gyrostat consists of a massive flywheel concealed in a solid casing. Its behaviour on a table, or with various modes of suspension or support, serves to illustrate the curious reversal of the ordinary laws of static equilibrium due to the gyrostatic behaviour of the interior invisible flywheel when rotated rapidly. The first gyrostat was designed by
Lord Kelvin William Thomson, 1st Baron Kelvin, (26 June 182417 December 1907) was a British mathematician A mathematician is someone who uses an extensive knowledge of mathematics Mathematics (from Greek: ) includes the study of such topics ...

to illustrate the more complicated state of motion of a spinning body when free to wander about on a horizontal plane, like a top spun on the pavement, or a bicycle on the road. Kelvin also made use of gyrostats to develop mechanical theories of the elasticity of matter and of the ether. In modern
continuum mechanics Continuum mechanics is a branch of mechanics Mechanics (Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Eu ...
there is a variety of these models, based on ideas of Lord Kelvin. They represent a specific type of Cosserat theories (suggested for the first time by Eugène Cosserat and François Cosserat), which can be used for description of artificially made smart materials as well as of other complex media. One of them, so-called Kelvin's medium, has the same equations as magnetic insulators near the state of magnetic saturation in the approximation of quasimagnetostatics. In modern times, the gyrostat concept is used in the design of attitude control systems for orbiting spacecraft and satellites. For instance, the Mir space station had three pairs of internally mounted flywheels known as ''gyrodynes'' or ''control moment gyros''. In physics, there are several systems whose dynamical equations resemble the equations of motion of a gyrostat. Examples include a solid body with a cavity filled with an inviscid, incompressible, homogeneous liquid, the static equilibrium configuration of a stressed elastic rod in elastica theory, the polarization dynamics of a light pulse propagating through a nonlinear medium, the
Lorenz system The Lorenz system is a system of ordinary differential equations first studied by Edward Norton Lorenz, Edward Lorenz. It is notable for having Chaos theory, chaotic solutions for certain parameter values and initial conditions. In particular, the ...

in chaos theory, and the motion of an ion in a
Penning trapA Penning trap is a device for the storage of charged particles using a homogeneous axial magnetic field A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materi ...
mass spectrometer.

## MEMS gyroscope

A
microelectromechanical systems Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems constitute the technology of microscopic devices, p ...
(MEMS) gyroscope is a miniaturized gyroscope found in electronic devices. It takes the idea of the
Foucault pendulum The Foucault pendulum or Foucault's pendulum is a simple device named after French physicist Léon Foucault and conceived as an experiment to demonstrate the Earth's rotation. The pendulum was introduced in 1851 and was the first experiment to gi ...

and uses a vibrating element. This kind of gyroscope was first used in military applications but has since been adopted for increasing commercial use.

## HRG

The hemispherical resonator gyroscope (HRG), also called a wine-glass gyroscope or mushroom gyro, 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 that surround the shell. Gyroscopic effect is obtained from the inertial property of the flexural standing waves.

## VSG or CVG

A
vibrating structure gyroscope A vibrating structure gyroscope, defined by the IEEE as a Coriolis vibratory gyroscope (CVG), is a gyroscope A gyroscope (from Ancient Greek γῦρος ''gûros'', "circle" and σκοπέω ''skopéō'', "to look") is a device used for meas ...
(VSG), also called a Coriolis vibratory gyroscope (CVG), uses a resonator made of different metallic alloys. It takes a position between the low-accuracy, low-cost MEMS gyroscope and the higher-accuracy and higher-cost fiber optic gyroscope. Accuracy parameters are increased by using low-intrinsic damping materials, resonator vacuumization, and digital electronics to reduce temperature dependent drift and instability of control signals. High quality wine-glass resonators are used for precise sensors like HRG.

## DTG

A dynamically tuned gyroscope (DTG) is a rotor suspended by a universal joint with flexure pivots. The flexure spring stiffness is independent of spin rate. However, the dynamic inertia (from the gyroscopic reaction effect) from the gimbal provides negative spring stiffness proportional to the square of the spin speed (Howe and Savet, 1964; Lawrence, 1998). Therefore, at a particular speed, called the tuning speed, the two moments cancel each other, freeing the rotor from torque, a necessary condition for an ideal gyroscope.

## Ring laser gyroscope

A
ring laser gyroscope A ring laser gyroscope (RLG) consists of a ring laser having two independent counter-propagating resonant modes over the same path; the difference in the frequencies is used to detect rotation. It operates on the principle of the Sagnac effect w ...
relies on the
Sagnac effect The Sagnac effect, also called Sagnac interference, named after French physicist Georges Sagnac, is a phenomenon encountered in interferometry that is elicited by rotation. The Sagnac effect manifests itself in a setup called a ring interferometer. ...
to measure rotation by measuring the shifting interference pattern of a beam split into two-halves, as the two-halves move around the ring in opposite directions. When the
Boeing 757 The Boeing 757 is an American narrow-body airliner A narrow-body aircraft or single-aisle aircraft is an airliner arranged along a single aisle, permitting up to 6-abreast airline seat, seating in a aircraft cabin, cabin below of width. In c ...

-200 entered service in 1983, it was equipped with the first suitable ring laser gyroscope. This gyroscope took many years to develop, and the experimental models went through many changes before it was deemed ready for production by the engineers and managers of
Honeywell Honeywell International Inc. is an American public company, publicly traded, multinational corporation, multinational conglomerate (company), conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four are ...

and
Boeing The Boeing Company () is an American multinational corporation A multinational company (MNC) is a corporate A corporation is an organization—usually a group of people or a company A company, abbreviated as co., is a Legal personal ...

. It was an outcome of the competition with mechanical gyroscopes, which kept improving. The reason Honeywell, of all companies, chose to develop the laser gyro was that they were the only one that didn't have a successful line of mechanical gyroscopes, so they wouldn't be competing against themselves. The first problem they had to solve was that with laser gyros rotations below a certain minimum could not be detected at all, due to a problem called "lock-in", whereby the two beams act like coupled oscillators and pull each other's frequencies toward convergence and therefore zero output. The solution was to shake the gyro rapidly so that it never settled into lock-in. Paradoxically, too regular of a dithering motion produced an accumulation of short periods of lock-in when the device was at rest at the extremities of its shaking motion. This was cured by applying a random
white noise In signal processing Signal processing is an electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, elect ...

to the vibration. The material of the block was also changed from quartz to a new glass ceramic
Cer-VitCer-vit is a family of glass-ceramic materials that were invented by Owens Illinois in the mid-1960s. Its principle ingredients are the oxides of lithium, aluminum and silicon. It is melted to form a glass which is then heat treated to nucleate and c ...
Owens Corning Owens Corning is an American company that develops and produces insulation, roofing, and fiberglass composites and related materials and products. It is the world's largest manufacturer of fiberglass composites. It was formed in 1935 as a partner ...
, because of helium leaks.

## Fiber optic gyroscope

A
fiber optic gyroscope A fibre-optic gyroscope (FOG) senses changes in orientation using the Sagnac effect, thus performing the function of a mechanical gyroscope A gyroscope (from Ancient Greek γῦρος ''gûros'', "circle" and σκοπέω ''skopéō'', "to l ...
also uses the interference of light to detect mechanical rotation. The two-halves of the split beam travel in opposite directions in a coil of
fiber optic An optical fiber (or fibre in British English British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, and standard) is a language variety that has undergone substantial codificati ...
cable as long as 5 km. Like the
ring laser gyroscope A ring laser gyroscope (RLG) consists of a ring laser having two independent counter-propagating resonant modes over the same path; the difference in the frequencies is used to detect rotation. It operates on the principle of the Sagnac effect w ...
, it makes use of the
Sagnac effect The Sagnac effect, also called Sagnac interference, named after French physicist Georges Sagnac, is a phenomenon encountered in interferometry that is elicited by rotation. The Sagnac effect manifests itself in a setup called a ring interferometer. ...
.

## London moment

A London moment gyroscope relies on the quantum-mechanical phenomenon, whereby a spinning generates a
magnetic field A magnetic field is a vector field In vector calculus and physics, a vector field is an assignment of a vector to each point in a subset of space. For instance, a vector field in the plane can be visualised as a collection of arrows with ...

whose axis lines up exactly with the spin axis of the gyroscopic rotor. A magnetometer determines the orientation of the generated field, which is
interpolated In the mathematics, mathematical field of numerical analysis, interpolation is a type of estimation, a method of constructing new data points within the range of a discrete set of known data points. In engineering and science, one often has a nu ...

to determine the axis of rotation. Gyroscopes of this type can be extremely accurate and stable. For example, those used in the
Gravity Probe B Gravity Probe B (GP-B) was a satellite-based experiment to test two unverified predictions of general relativity: the geodetic effect and frame-dragging. This was to be accomplished by measuring, very precisely, tiny changes in the direction of s ...

experiment measured changes in gyroscope spin axis orientation to better than 0.5 milliarcseconds (1.4 degrees, or about ) over a one-year period. This is equivalent to an
angular separation Angular may refer to: Anatomy * Angular artery The angular artery is the terminal part of the facial artery; it ascends to the medial angle of the eye's orbit, imbedded in the fibers of the angular head of the quadratus labii superioris, and accomp ...
the width of a human hair viewed from away. The GP-B gyro consists of a nearly-perfect spherical rotating mass made of
fused quartz Fused quartz, fused silica or quartz glass is a glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window pa ...
, which provides a
dielectric In electromagnetism Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electric charge, electrically charged particles. The electromagnetic force i ...

support for a thin layer of
niobium Niobium, also known as columbium, is a chemical element with the Symbol (chemistry), symbol Nb (formerly Cb) and atomic number 41. Niobium is a light grey, crystalline, and ductile transition metal. Pure niobium has a Mohs scale of mineral har ...

superconducting material. To eliminate friction found in conventional bearings, the rotor assembly is centered by the electric field from six electrodes. After the initial spin-up by a jet of helium which brings the rotor to 4,000
RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or with the notation min−1) is the number of turns in one minute The minute is a unit Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the ...
, the polished gyroscope housing is evacuated to an ultra-high vacuum to further reduce drag on the rotor. Provided the suspension electronics remain powered, the extreme
rotational symmetry Rotational symmetry, also known as radial symmetry in geometry Geometry (from the grc, γεωμετρία; ' "earth", ' "measurement") is, with , one of the oldest branches of . It is concerned with properties of space that are related ...
, lack of friction, and low drag will allow the angular momentum of the rotor to keep it spinning for about 15,000 years. A sensitive that can discriminate changes as small as one quantum, or about 2 Wb, is used to monitor the gyroscope. A
precession Precession is a change in the orientation Orientation may refer to: Positioning in physical space * Map orientation, the relationship between directions on a map and compass directions * Orientation (housing), the position of a building with re ...

, or tilt, in the orientation of the rotor causes the London moment magnetic field to shift relative to the housing. The moving field passes through a superconducting pickup loop fixed to the housing, inducing a small electric current. The current produces a voltage across a shunt resistance, which is resolved to spherical coordinates by a microprocessor. The system is designed to minimize Lorentz torque on the rotor.

# Other examples

## Helicopters

The main rotor of a helicopter acts like a gyroscope. Its motion is influenced by the principle of gyroscopic precession which is the concept that a force applied to a spinning object will have a maximum reaction approximately 90 degrees later. The reaction may differ from 90 degrees when other stronger forces are in play. To change direction, helicopters must adjust the pitch angle and the angle of attack.

## Gyro X

A prototype vehicle created by Alex Tremulis and Thomas Summers in 1967. The car utilizes gyroscopic precession to drive on two wheels. An assembly consisting of a flywheel mounted in a gimbal housing under the hood of the vehicle acted as a large gyroscope. The flywheel was rotated by hydraulic pumps creating a gyroscopic effect on the vehicle. A precessional ram was responsible for rotating the gyroscope to change the direction of the precessional force to counteract any forces causing the vehicle imbalance. The one-of-a-kind prototype is now at the Lane Motor Museum in Nashville, Tennessee.

# Consumer electronics

In addition to being used in compasses, aircraft, computer pointing devices, etc., gyroscopes have been introduced into consumer electronics. The first usage or application of the gyroscope in consumer electronics was popularized by
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in the Apple
iPhone {{Infobox information appliance , name = iPhone , logo = , image = , caption = The front face of an iPhone 13 Pro The iPhone 13 Pro and iPhone 13 Pro Max are smartphones designed and marketed by Apple Inc. They are the flagship smart ...

. Since the gyroscope allows the calculation of orientation and rotation, designers have incorporated them into modern technology. The integration of the gyroscope has allowed for more accurate recognition of movement within a 3D space than the previous lone accelerometer within a number of smartphones. Gyroscopes in consumer electronics are frequently combined with accelerometers (acceleration sensors) for more robust direction- and motion-sensing. Examples of such applications include smartphones such as the
Samsung Galaxy Note 4 The Samsung Galaxy Note 4 is an Android smartphone A smartphone is a mobile device that combines cellular and mobile computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and ...

, HTC Titan,
Nexus 5 Nexus 5 (code-named Hammerhead) is an Android Android may refer to: Science and technology * Android (robot), a humanoid robot or synthetic organism designed to imitate a human * Android (operating system), Google's mobile operating syst ...

,
iPhone 5s The iPhone 5S (stylized and marketed as iPhone 5s) is a smartphone A smartphone is a portable device A mobile device (or handheld computer) is a computer A computer is a machine that can be programmed to carry out sequences of a ...

,
Nokia 808 PureView The Nokia 808 PureView is a Symbian Symbian is a discontinued mobile operating system A mobile operating system is an operating system An operating system (OS) is system software that manages computer hardware, computer software, soft ...
and
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, game console peripherals such as the and the
Wii Remote The Wii Remote, also known colloquially Colloquialism or colloquial language is the style (sociolinguistics), linguistic style used for casual (informal) communication. It is the most common functional style of speech, the idiom normally employe ...

, and virtual reality sets such as the
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.
Nintendo is a Japanese Multinational corporation, multinational consumer electronics and video game company headquartered in Kyoto, Japan. The company was founded in 1889 as by craftsman Fusajiro Yamauchi and originally produced handmade playing ca ...

has integrated a gyroscope into the
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console's Wii Remote controller by an additional piece of hardware called "
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". It is also included in the 3DS, Wii U GamePad, and
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controllers, which detect movement when turning and shaking. Cruise ships use gyroscopes to level motion-sensitive devices such as self-leveling pool tables. An electric powered flywheel gyroscope inserted in a bicycle wheel is sold as an alternative to training wheels. Some features of Android phones like PhotoSphere or 360 Camera and to use VR gadget do not work without a gyroscope sensor in the phone.

* Aerotrim *
Accelerometer An accelerometer is a tool that measures proper acceleration In relativity theory, proper acceleration is the physical acceleration (i.e., measurable acceleration as by an accelerometer) experienced by an object. It is thus acceleration relative ...

* Anti-rolling gyro *
Attitude indicator The attitude indicator (AI), formerly known as the gyro horizon or artificial horizon, is a that informs the pilot of the aircraft relative to Earth's horizon, and gives an immediate indication of the smallest orientation change. The miniature ...
*
Balancing machine A balancing machine is a measuring tool used for balancing rotating machine parts such as rotors for electric motors, fans, turbine A turbine ( or ) (from the Greek , ''tyrbē'', or Latin Latin (, or , ) is a classical language belonging to ...
*
Countersteering Countersteering is used by single-track vehicle operators, such as cyclists and motorcyclists, to initiate a turn toward a given direction by momentarily steering counter to the desired direction ("steer left to turn right"). To negotiate a turn ...

*
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*
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* Gyrocar * Gyro monorail * Gyroscopic exercise tool *
Inertial measurement unit#REDIRECT Inertial measurement unit An inertial measurement unit (IMU) is an electronic device that measures and reports a body's specific force, angular rate, and sometimes the orientation of the body, using a combination of accelerometers, gy ...
*
Magnetometer A magnetometer is a device that measures magnetic field A magnetic field is a vector field In vector calculus and physics, a vector field is an assignment of a vector to each point in a subset of space. For instance, a vector field in ...
*
Molecular gyroscope A molecule is an electrically Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change in position In physics, motion is the phenomenon ...
* Reaction wheel * Rifling * Rigid body dynamics * Turn and bank indicator * Turn coordinator * Stabilizer (ship), Stabilizer

# References

*

* Felix Klein and Arnold Sommerfeld, "''Über die Theorie des Kreisels''" (Tr., About the theory of the gyroscope). Leipzig, Berlin, B.G. Teubner, 1898–1914. 4 v. illus. 25 cm. * Audin, M. ''Spinning Tops: A Course on Integrable Systems''. New York: Cambridge University Press, 1996. * Crabtree, H. "An Elementary Treatment of the Theory of Spinning Tops and Gyroscopic Motion". Longman, Green and C), 1909. Reprinted by Michigan Historical Reprint Series. * Proceedings of Anniversary Workshop on Solid-State Gyroscopy, 19–21 May 2008. Yalta, Ukraine. Kyiv-Kharkiv. ATS of Ukraine, (2009) * E. Leimanis (1965). ''The General Problem of the Motion of Coupled Rigid Bodies about a Fixed Point''. (Springer, New York). * Perry J. "Spinning Tops". London Society for Promoting Christian Knowledge, 1870. Reprinted by Project Gutemberg ebook, 2010. * Walter Wrigley, Walter M. Hollister, and William G. Denhard (1969). ''Gyroscopic Theory, Design, and Instrumentation.'' (MIT Press, Cambridge, MA). * Provatidis, C. G. (2012). Revisiting the Spinning Top, ''International Journal of Materials and Mechanical Engineering'', Vol. 1, No. 4, pp. 71–88, open access a
Ijm-me.org
(ISSN Online: 2164-280X, ISSN Print: 2162-0695). * Cooper, Donald & University of Western Australia. Dept. of Mechanical and Materials Engineering 1996, An investigation of the application of gyroscopic torque in the acceleration and retardation of rotating systems.