Vibrating structure gyroscope
Encyclopedia
A vibrating structure gyroscope is a type of
gyroscope
that functions much like the halteres
of an insect.
The underlying physical principle is that a vibrating
object tends to continue vibrating in the same plane
as its support rotates. In the engineering literature, this type of device
is also known as a Coriolis vibratory gyro because
as the plane of oscillation is rotated, the response
detected by the transducer results from the Coriolis
term in its equations of motion ("Coriolis force").
Vibrating structure gyroscopes are
simpler and cheaper than conventional rotating
gyroscopes of similar accuracy.
Miniaturized devices using this principle
are a relatively inexpensive type of
attitude indicator
.
. Recall that the Coriolis effect
induces an acceleration on the proof masses equal to
, where 
is a velocity
and
is an angular rate
of rotation. The in-plane velocity of the proof masses is given by:
, if the in-plane position is given by 
. The out-of-plane motion 
, induced by rotation, is given by:
where
is a mass of the proof mass,
is a spring constant in the out of plane direction,
is a magnitude of a rotation vector in the plane of and perpendicular to the driven proof mass motion.
In application to axi-symmetric thin-walled structures like beams and shells, the Coriolis forces cause a precession of vibration pattern about the axis of rotation. For such shells, it causes a slow precession of a standing wave about this axis with an angular rate which differs from input one. It is so-called "wave inertia effect" discovered in 1890 by British scientist George Hartley Bryan
(1864–1928).
If we consider a polarization of a shear (transverse) elastic wave propagating along an acoustic axis in a solid, a polarization rotation effect due to rotation of the body as a whole (so-called, "polarization inertia effect") can be observed too (it was noted by Ukrainian scientist Sergii A. Sarapuloff in early 80th, as well as a corresponding modification of Green-Christoffel's tensors in Acoustics).
can be measured to produce a signal related to the rate of rotation.
discovery of the underlying physical phenomenon,
Dr. David D. Lynch, et al developed and patented several variants of such gyros for the Space & Launch divisions of Delco Electronics / General Motors Corp., Litton Guidance & Control Systems, and Northrop Grumman Corp. (CA, USA). There are two basic variants of the system, one based on a rate regime of operation and one based on an integrating regime of operation, usually in combination with a controlled parametric excitation. It is possible to use both regimes with the same hardware, which is a feature unique to this type of gyroscope. Engineers and researchers in several countries have been working on the technology.
F.W. Meredith registered a patent for such a device in 1942 while working at the Royal Aircraft Establishment
. Further development was carried out at the RAE in the late 1950s by G.H. Hunt and A.E.W. Hobbs, who demonstrated drift of less than 1 °/h (3.6×10−4 °/s).
Modern variants of tactical gyros use doubled tuning fork
s such as those produced by SAGEM Défence Securité / Safran Group
(France).
technology have become widely available. These are packaged
similarly to other integrated circuit
s and may provide either analog or digital outputs. In many cases, a single part includes gyroscopic sensors for multiple axes. Some parts incorporate both a gyroscope and an accelerometer
, in which case the output has six full degrees of freedom. Panasonic
, Robert Bosch GmbH
, InvenSense, Seiko Epson
, STMicroelectronics
, and Analog Devices
are major manufacturers.
Internally, MEMS gyroscopes use lithographically constructed versions of one or more of the mechanisms outlined above (tuning forks, vibrating wheels, or resonant solids of various designs).
positioning of spacecraft such as Cassini-Huygens. These small Hemispherical Resonator Gyroscopes made of quartz glass
operate in vacuum. There are also prototypes of Cylindrical Resonator Gyroscopes (CRG) made from high-purity single-crystalline sapphire
. They provide accurate 3 axis positioning of the spacecraft and are highly reliable over the years as they don't have any moving parts.
systems in conjunction with a steering wheel sensor. Advanced systems could conceivably offer rollover detection based on a second VSG but it is cheaper to add longitudinal and vertical accelerometers to the existing lateral one to this end.
uses a piezoelectric gyroscope to detect rotational movement. The Sony SIXAXIS
PS3 controller uses a single MEMS gyroscope to measure the sixth axis (yaw). The Nintendo Wii MotionPlus
accessory uses multi-axis MEMS
gyroscopes provided by InvenSense to augment the motion sensing capabilities of the Wii Remote
. The iPhone 4
, iPad2, iPod Touch
, Nintendo 3DS
, Nexus S
and HTC Titan
also feature gyroscopes.
systems on video and still cameras employ vibrating structure gyroscopes.
s to help control the helicopter's tail rotor or in radio-controlled airplanes to help keep the tail steady during take-off or hand (especially with discus launched glider
s) launch.
gyroscope
Gyroscope
A gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum. In essence, a mechanical gyroscope is a spinning wheel or disk whose axle is free to take any orientation...
that functions much like the halteres
Halteres
Halteres are small knobbed structures modified from the hind wings in some two-winged insects. They are flapped rapidly and function as gyroscopes, informing the insect about rotation of the body during flight....
of an insect.
The underlying physical principle is that a vibrating
object tends to continue vibrating in the same plane
as its support rotates. In the engineering literature, this type of device
is also known as a Coriolis vibratory gyro because
as the plane of oscillation is rotated, the response
detected by the transducer results from the Coriolis
term in its equations of motion ("Coriolis force").
Vibrating structure gyroscopes are
simpler and cheaper than conventional rotating
gyroscopes of similar accuracy.
Miniaturized devices using this principle
are a relatively inexpensive type of
attitude indicator
Attitude indicator
An attitude indicator , also known as gyro horizon or artificial horizon, is an instrument used in an aircraft to inform the pilot of the orientation of the aircraft relative to earth. It indicates pitch and bank or roll and is a primary instrument for flight in instrument meteorological conditions...
.
Theory of operation
Consider two proof masses vibrating in plane (as in the MEMS gyro) at frequency. Recall that the Coriolis effectCoriolis effect
In physics, the Coriolis effect is a deflection of moving objects when they are viewed in a rotating reference frame. In a reference frame with clockwise rotation, the deflection is to the left of the motion of the object; in one with counter-clockwise rotation, the deflection is to the right...
induces an acceleration on the proof masses equal to
, where is a velocityVelocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
and
is an angular rateAngular frequency
In physics, angular frequency ω is a scalar measure of rotation rate. Angular frequency is the magnitude of the vector quantity angular velocity...
of rotation. The in-plane velocity of the proof masses is given by:
, if the in-plane position is given by . The out-of-plane motion , induced by rotation, is given by:where
is a mass of the proof mass, is a spring constant in the out of plane direction, is a magnitude of a rotation vector in the plane of and perpendicular to the driven proof mass motion.In application to axi-symmetric thin-walled structures like beams and shells, the Coriolis forces cause a precession of vibration pattern about the axis of rotation. For such shells, it causes a slow precession of a standing wave about this axis with an angular rate which differs from input one. It is so-called "wave inertia effect" discovered in 1890 by British scientist George Hartley Bryan
George H. Bryan
George Hartley Bryan FRS, generally referred to in the technical literature as G. H. Bryan, was a professor at University College, Bangor, Wales who is generally credited with developing the modern mathematical treatment of the motion of airplanes in flight as rigid bodies with six degrees of freedom...
(1864–1928).
If we consider a polarization of a shear (transverse) elastic wave propagating along an acoustic axis in a solid, a polarization rotation effect due to rotation of the body as a whole (so-called, "polarization inertia effect") can be observed too (it was noted by Ukrainian scientist Sergii A. Sarapuloff in early 80th, as well as a corresponding modification of Green-Christoffel's tensors in Acoustics).
Piezoelectric gyroscope
A piezoelectric material can be induced to vibrate, and lateral motion due to centrifugal forceCentrifugal force
Centrifugal force can generally be any force directed outward relative to some origin. More particularly, in classical mechanics, the centrifugal force is an outward force which arises when describing the motion of objects in a rotating reference frame...
can be measured to produce a signal related to the rate of rotation.
Wine glass resonator
Also called a hemispherical resonator gyro or HRG, a wine glass resonator makes use of a hemisphere driven to resonance, the nodal points of which are measured to detect rotation. Almost a century after George H. Bryan'sGeorge H. Bryan
George Hartley Bryan FRS, generally referred to in the technical literature as G. H. Bryan, was a professor at University College, Bangor, Wales who is generally credited with developing the modern mathematical treatment of the motion of airplanes in flight as rigid bodies with six degrees of freedom...
discovery of the underlying physical phenomenon,
Dr. David D. Lynch, et al developed and patented several variants of such gyros for the Space & Launch divisions of Delco Electronics / General Motors Corp., Litton Guidance & Control Systems, and Northrop Grumman Corp. (CA, USA). There are two basic variants of the system, one based on a rate regime of operation and one based on an integrating regime of operation, usually in combination with a controlled parametric excitation. It is possible to use both regimes with the same hardware, which is a feature unique to this type of gyroscope. Engineers and researchers in several countries have been working on the technology.
Coriolis Vibratory Gyroscope (CVG)
This type of gyroscope was developed and patented by Innalabs uses alloys or metal based cylindrical design resonator, which can be designed as an axisymmetrical shape or not, but only axisymmetrical shapes lead to top of the range performances. This breakthrough technology allowed substantially increase product life of the gyroscopes (MTBF > 500,000 hours) and their shock resistance (>300g). The resonator is operated on its second order resonant modes. Standing waves are therefore elliptical shape oscillations with four antinodes and four nodes located circumferentially along the rim, angle between two adjacent antinode – node being 45 deg. One of the elliptical resonant modes is excited to a prescribed amplitude. When the device rotates about its sensitive axis (along its inner stem), the resulting Coriolis forces acting on the resonator’s vibrating mass elements excite the second resonant mode. Angle between major axis of the two modes is 45 deg. A closed-loop drives the second resonant mode to zero and the force required to null this mode is proportional to the input rotation rate. Corresponding control loop system is called force-rebalanced mode. In order to provide forces and to sense induced motions, piezo-electric elements placed on the resonator are used. This electromechanical system is particularly effective and leads to low output noise and large dynamic range as required in case of demanding applications.Tuning fork gyroscope
This type of gyroscope uses a pair of test masses which are driven to resonance. Their displacement from the plane of oscillation is then measured to produce a signal related to the system's rate of rotation.F.W. Meredith registered a patent for such a device in 1942 while working at the Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...
. Further development was carried out at the RAE in the late 1950s by G.H. Hunt and A.E.W. Hobbs, who demonstrated drift of less than 1 °/h (3.6×10−4 °/s).
Modern variants of tactical gyros use doubled tuning fork
Tuning fork
A tuning fork is an acoustic resonator in the form of a two-pronged fork with the prongs formed from a U-shaped bar of elastic metal . It resonates at a specific constant pitch when set vibrating by striking it against a surface or with an object, and emits a pure musical tone after waiting a...
s such as those produced by SAGEM Défence Securité / Safran Group
SAFRAN
Safran is a French conglomerate involved in defense, aerospace propulsion and equipment, and security. It is the result of a merger between the propulsion and aerospace equipment group SNECMA and the defense conglomerate SAGEM. Its headquarters are located in Paris.The name Safran, literally...
(France).
Vibrating wheel gyroscope
A wheel is driven to rotate a fraction of a full turn about its axis. The tilt of the wheel is measured to produce a signal related to the rate of rotation.MEMS gyroscope
Inexpensive (as of 2010, approximately US$5 per part in quantity) vibrating structure gyroscopes manufactured with MEMSMicroelectromechanical systems
Microelectromechanical systems is the technology of very small mechanical devices driven by electricity; it merges at the nano-scale into nanoelectromechanical systems and nanotechnology...
technology have become widely available. These are packaged
Chip carrier
A chip carrier, also known as a chip container or chip package, is a container for a transistor or an integrated circuit. The carrier usually provides metal leads, or "pins", which are sturdy enough to electrically and mechanically connect the fragile chip to a circuit board. This connection may be...
similarly to other integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s and may provide either analog or digital outputs. In many cases, a single part includes gyroscopic sensors for multiple axes. Some parts incorporate both a gyroscope and an accelerometer
Accelerometer
An accelerometer is a device that measures proper acceleration, also called the four-acceleration. This is not necessarily the same as the coordinate acceleration , but is rather the type of acceleration associated with the phenomenon of weight experienced by a test mass that resides in the frame...
, in which case the output has six full degrees of freedom. Panasonic
Panasonic
Panasonic is an international brand name for Japanese electric products manufacturer Panasonic Corporation, which was formerly known as Matsushita Electric Industrial Co., Ltd...
, Robert Bosch GmbH
Robert Bosch GmbH
Robert Bosch GmbH is a multinational engineering and electronics company headquartered in Gerlingen, near Stuttgart, Germany. It is the world's largest supplier of automotive components...
, InvenSense, Seiko Epson
Seiko Epson
, commonly known as Epson, is a Japanese technology company and one of the world's largest manufacturers of computer printers, information and imaging related equipment...
, STMicroelectronics
STMicroelectronics
STMicroelectronics is an Italian-French electronics and semiconductor manufacturer headquartered in Geneva, Switzerland.While STMicroelectronics corporate headquarters and the headquarters for EMEA region are based in Geneva, the holding company, STMicroelectronics N.V. is registered in Amsterdam,...
, and Analog Devices
Analog Devices
Analog Devices, Inc. , known as ADI, is an American multinational semiconductor company specializing in data conversion and signal conditioning technology, headquartered in Norwood, Massachusetts...
are major manufacturers.
Internally, MEMS gyroscopes use lithographically constructed versions of one or more of the mechanisms outlined above (tuning forks, vibrating wheels, or resonant solids of various designs).
Spacecraft orientation
The oscillation can also be induced and controlled in the vibrating structure gyroscope for thepositioning of spacecraft such as Cassini-Huygens. These small Hemispherical Resonator Gyroscopes made of quartz glass
Fused quartz
Fused quartz and fused silica are types of glass containing primarily silica in amorphous form. They are manufactured using several different processes...
operate in vacuum. There are also prototypes of Cylindrical Resonator Gyroscopes (CRG) made from high-purity single-crystalline sapphire
Sapphire
Sapphire is a gemstone variety of the mineral corundum, an aluminium oxide , when it is a color other than red or dark pink; in which case the gem would instead be called a ruby, considered to be a different gemstone. Trace amounts of other elements such as iron, titanium, or chromium can give...
. They provide accurate 3 axis positioning of the spacecraft and are highly reliable over the years as they don't have any moving parts.
Automotive
Automotive yaw sensors can be built around vibrating structure gyroscopes. These are used to detect error states in yaw compared to a predicted response when connected as an input to electronic stability controlElectronic stability control
Electronic stability control is a computerized technology that may potentially improve the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, it automatically applies the brakes to help "steer" the vehicle where the driver intends to go...
systems in conjunction with a steering wheel sensor. Advanced systems could conceivably offer rollover detection based on a second VSG but it is cheaper to add longitudinal and vertical accelerometers to the existing lateral one to this end.
Entertainment
The Nintendo Game Boy Advance game WarioWare: Twisted!WarioWare: Twisted!
WarioWare: Twisted!, known in Japan as is a video game for Game Boy Advance by Nintendo. The game is of a variety and puzzle genre. It was released on October 14, 2004 in Japan, May 23, 2005 in North America, and May 19, 2005 in Australia. It was not released in Europe, despite having been...
uses a piezoelectric gyroscope to detect rotational movement. The Sony SIXAXIS
Sixaxis
The Sixaxis Wireless Controller was the official gamepad for the Sony PlayStation 3 from launch until 2008 when it was succeeded by the DualShock 3....
PS3 controller uses a single MEMS gyroscope to measure the sixth axis (yaw). The Nintendo Wii MotionPlus
Wii MotionPlus
The is an expansion device for the Wii Remote video game controller for the Wii that allows it to more accurately capture complex motion. According to Nintendo, the sensor in the device supplements the accelerometer and Sensor Bar capabilities of the Wii Remote to enable actions to be rendered...
accessory uses multi-axis MEMS
Microelectromechanical systems
Microelectromechanical systems is the technology of very small mechanical devices driven by electricity; it merges at the nano-scale into nanoelectromechanical systems and nanotechnology...
gyroscopes provided by InvenSense to augment the motion sensing capabilities of the Wii Remote
Wii Remote
The , also known as the Wiimote, is the primary controller for Nintendo's Wii console. A main feature of the Wii Remote is its motion sensing capability, which allows the user to interact with and manipulate items on screen via gesture recognition and pointing through the use of accelerometer and...
. The iPhone 4
IPhone 4
The iPhone 4 is a touchscreen slate smartphone developed by Apple Inc. It is the fourth generation iPhone, and successor to the iPhone 3GS. It is particularly marketed for video calling , consumption of media such as books and periodicals, movies, music, and games, and for general web and e-mail...
, iPad2, iPod Touch
IPod Touch
The iPod Touch is a portable media player, personal digital assistant, handheld game console, and Wi-Fi mobile device designed and marketed by Apple Inc. The iPod Touch adds the multi-touch graphical user interface to the iPod line...
, Nintendo 3DS
Nintendo 3DS
The is a portable game console produced by Nintendo. The autostereoscopic device is able to project stereoscopic 3D effects without the use of 3D glasses or any additional accessories. The Nintendo 3DS features backward compatibility with Nintendo DS series software, including Nintendo DSi software...
, Nexus S
Nexus S
The Nexus S is a smartphone co-developed by Google and Samsung and manufactured by Samsung Electronics. It was the first smartphone to use the Android 2.3 "Gingerbread" operating system, and the first Android device to support Near Field Communication in both hardware and software...
and HTC Titan
HTC Titan
The HTC Titan is an EVDO Rev. A Windows Mobile 6.1 Pocket PC phone manufactured by High Tech Computer Corporation of Taiwan. It is the successor to the HTC Apache upon which it improves by adding more ROM, GPS, EVDO Rev. A, additional hard keys, a scroll-wheel, spring-loaded keyboard, and a higher...
also feature gyroscopes.
Photography
Many Image stabilizationImage stabilization
Image stabilization is a family of techniques used to reduce blurring associated with the motion of a camera during exposure. Specifically, it compensates for pan and tilt of a camera or other imaging device. It is used in image-stabilized binoculars, still and video cameras, and astronomical...
systems on video and still cameras employ vibrating structure gyroscopes.
Hobbies
Vibrating structure gyroscopes are commonly used in radio-controlled helicopterRadio-controlled helicopter
Radio-controlled helicopters are model aircraft which are distinct from RC airplanes because of the differences in construction, aerodynamics, and flight training...
s to help control the helicopter's tail rotor or in radio-controlled airplanes to help keep the tail steady during take-off or hand (especially with discus launched glider
Discus Launch Glider (DLG), Radio Controlled
A Discus Launch Glider is a radio controlled model sailplane launched using a 'discus launch' in which the glider is held by a wingtip and rotated around the flyer by hand before release...
s) launch.
Other
The Segway Human Transporter employs a vibrating structure gyroscope made by Silicon Sensing Systems to maintain stability of the operator platform.External links
- Proceedings of Anniversary Workshop on Solid-State Gyroscopy (19–21 May 2008. Yalta, Ukraine). - Kyiv-Kharkiv. ATS of Ukraine. 2009. - ISBN 978-976-02-5248-6. See also the next meetings at: International Workshops on Solid-State Gyroscopy http://www.facebook.com/pages/International-Workshops-on-Solid-State-Gyroscopy/135430619833718.
- Silicon Sensing - Case Study: Segway HT
- Apostolyuk V. Theory and Design of Micromechanical Vibratory Gyroscopes
- Prandi L. , Antonello R., Oboe R., and Biganzoli F. Automatic Mode-Matching in MEMS Vibrating Gyroscopes Using Extremum Seeking Control //IEEE Transactions on Industrial Electronics. 2009. Vol.56. - P.3880-3891.. http://automatica.dei.unipd.it/publications.html?autore=autore&condizione=228&testo=UHVibGljYXRpb25zIG9mIGF1dGhvciBSb2JlcnRvIE9ib2U=
- Prandi L., Antonello R., Oboe R., Caminada C., and Biganzoli F. Open-Loop Compensation of the Quadrature Error in MEMS Vibrating Gyroscopes //Proceedings of 35th Annual Conference of the IEEE Industrial Electronics Society - IECON-2009. 2009. http://automatica.dei.unipd.it/publications.html?autore=autore&condizione=228&testo=UHVibGljYXRpb25zIG9mIGF1dGhvciBSb2JlcnRvIE9ib2U=