Gyroscope control. How it works: gyroscope

Many interesting features and sensors are equipped with smartphones and other mobile devices. One of the leading modules is a gyro sensor or gyroscope. An outlandish novelty in the device, made on the basis of a microelectromechanical system, made a big leap in improving functionality and won great sympathy among users. The origin of the word “gyroscope” has a long history. It stands for the phrase “circle” and “I look.”

The founder of the ancient Greek saying was the French physicist Leon Foucault. In the 19th century, he was studying the daily rotation of the Earth, and this term was perfect for the new device. Gyro sensors are used by airlines, shipping, and astronautics. Apple Company, manufacturer of modern mobile phones, was the first to take this functionality as a basis and implement it in the iPhone 4. Despite the fact that the video below is on English language, a technology demonstration from Steve Jobs is understandable without translation.

Now, in order to answer incoming calls or scroll through pages e-book, just shake your phone. Thanks to the device, photos and other images are quickly viewed, and the music changes. A new application on the iPone smartphone called CoveFlow allows you to use a calculator. Functions such as division, multiplication, addition and subtraction are now easily performed. When the phone is rotated 90° this function automatically switches to extensive functionality with many complex mathematical operations.

Along with easy functions, the developers have introduced more complex ones into the device. software. For example, in some operating systems By shaking the phone, an update for Bluetooth is launched or a specific program for measuring inclination angles and levels is launched. The gyroscope perfectly takes into account the speed of movement and determines the location of a person in unfamiliar terrain.

From a technical point of view, a gyroscope is a rather complex device. When developing it, we took as a basis the principle of operation of an accelerometer, which is a flask with a spring and a weight inside. A weight is attached to one side of the spring, and the other side of the spring is fixed to a damper to dampen vibrations. When the measuring instrument is shaken (accelerated), the attached mass moves and tensions the spring.

Such fluctuations can be represented in the form of data. If you place three such accelerometers perpendicularly, you can get an idea of ​​how an object is located in space. Since it is technically possible to place such a bulky measuring device impossible in a smartphone, the operating principle was left the same, but the load was replaced with an inert mass, which is located in a very small chip. When accelerating, the position of the inertial mass changes and thus the position of the smartphone in space is calculated.

With the help of GPS navigation, a map appears on the display that records the same direction of objects for any rotation of the body. In other words, if you are facing a river, it will automatically appear on the map. When turning 180 degrees towards a body of water, similar changes instantly occur on the monitor. Using this function makes it easier to navigate the area. This is especially important for people involved active species recreation.

Thanks to accurate tracking of movement speed, smartphone control becomes more convenient and harmonious. Amateurs often use gyroscopes on Android computer games- gamers. A unique device in the device instantly turns pictures into reality. Racing games, simulators, shooting games, and Pokemon Go become especially plausible.

Just change the position of your smartphone and the speed of rotation, and driving a virtual car will seem real to you. The heroes on the display will accurately point the machine gun, aim the cannon, turn the steering wheel, lift the helicopter into the air, and kill the enemy. Pocket monsters will not jump on virtual grass, but will move around the real world in the visible area of ​​the built-in camera.

Of course, this is not the entire list of positive characteristics inherent in Android smartphones and iPhone. The list of pleasant and convenient moments is endless. However, not all users appreciated the universal qualities. Some chose to abandon the gyroscope in the new smartphone, others simply turned it off. And there is an explanation for this.
Among the many advantages, there are subtle disadvantages.

1. One of the disadvantages is the installation of individual applications that react with a slight delay to changes in positions in space. It seems like a mere trifle, but the presence of this sensor causes certain inconvenience to the smartphone user. The disadvantages are especially noticeable when reading an e-book while lying down. The reader changes his position, at the same time, a gyro sensor connected to the device changes the position of the page. We have to urgently reconfigure its orientation.
2. Smartphone manufacturers in their presentations in most cases are silent about the presence of an important sensor. When purchasing a new model, the presence of a gyroscope can be detected in technical specifications gadget in the list of sensors. There are other ways, for example, installing the YouTube client, which allows you to quickly install the functionality. Using the AnTuTu Benchmark app, Sensor Sense also determines the built-in gyro sensor or lack thereof.

The modern element of a smartphone works on an ongoing basis. This is an independent sensor that does not require calibration. It does not need to be turned on or off. Automation will do this work for you. If the device is missing, you will not be able to play virtual reality. You'll just have to buy new phone with built-in functions.

Nowadays, all smartphones are equipped with at least one sensor, and most often several. The most common sensors are proximity, lighting and motion sensors. Most smartphones are equipped with an accelerometer that responds to device movement in two or maximum three planes. To fully interact with a virtual reality headset, you need a gyroscope that detects movements in any direction.

The gyroscope in a smartphone is a microelectromechanical converter of angular velocities into an electrical signal. In other words, this sensor calculates the change in the angle of inclination relative to the axis when the device is rotated.

A gyroscope belongs to microelectromechanical systems (MEMS), which combine mechanical and electronic parts. Such chips are on the order of a couple of millimeters or less in size.

A conventional gyroscope consists of an inertial object that rapidly rotates around its axis. Thus, it maintains its direction, and the displacement of the controlled object is measured by changing the position of the suspensions. Such a top obviously won’t fit into smartphones; MEMS is used instead.

Converting mechanical motion into electrical signal

The simplest single-axis gyroscope has two moving masses moving in opposite directions (shown in blue in the picture). As soon as an external angular velocity is applied, the mass is subject to a Coriolis force, which is directed perpendicular to their motion (marked in orange).

Under the influence of the Coriolis force, the masses shift by an amount proportional to the applied speed. Changing the position of the masses changes the distance between the moving electrodes (rotors) and stationary electrodes (stators), which leads to a change in the capacitance of the capacitor and, accordingly, the voltage on its plates, and this is an electrical signal. It is these multiple signals that are recognized by the MEMS gyroscope, determining the direction and speed of movement.

Calculating smartphone orientation

The microcontroller receives the voltage information and converts it into angular velocity at the moment. The magnitude of the angular velocity can be determined with a given accuracy, for example, up to 0.001 degrees per second. To determine how many degrees around the axis the device was rotated, it is necessary to multiply the instantaneous speed by the time between two sensor readings. If we use a three-axis gyroscope, we will receive data on rotations relative to all three axes, that is, in this way we can determine the orientation of the smartphone in space.

It is worth noting here that to obtain the angle values, it is necessary to integrate the original equations, which include angular velocities. With each integration the error increases. If you calculate the position only using a gyroscope, then over time the calculated values ​​will become incorrect.

Therefore, in smartphones, to accurately determine orientation in space, accelerometer data is also required. This sensor measures linear acceleration but does not respond to cornering. Both sensors are capable of fully describing all types of motion. The main advantage of a gyroscope over an accelerometer is that it responds to movement in any direction.

Why do you need a gyroscope in a smartphone?

This sensor has received increased attention over the last couple of years, when games and virtual reality applications began to actively develop. For user interaction with virtual reality, the program needs to accurately determine the person’s position in space. Now even in the most budget smartphones An accelerometer is installed, but its readings are accompanied by noise, and the sensor does not respond to turns and movements in the horizontal plane. Therefore, for complete immersion in virtual reality, a smartphone must have a gyroscope and an accelerometer.

How to find out if your smartphone has a gyroscope

Typically, the characteristics of a smartphone indicate what sensors it has. If you doubt the veracity of the information, they will help special programs. For example, Sensor Box for Android shows information about all built-in sensors. The gyroscope is designated as Gyroscope. There are other methods that we described in this article.

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GYROSCOPE (from the Greek γ?ρος - circle, circle and σκοπ?ω - to observe), a device that makes rapid cyclic (rotational or oscillatory) movements and is therefore sensitive to rotation in inertial space. The term “gyroscope” was proposed in 1852 by J. B. L. Foucault for the device he invented, designed to demonstrate the rotation of the Earth around its axis. For a long time, the term "gyroscope" was used to refer to a rapidly rotating symmetrical rigid body. In modern technology, a gyroscope is the main element of all kinds of gyroscopic devices or instruments, widely used for automatic control of the movement of aircraft, ships, torpedoes, missiles, spacecraft, mobile robots, for navigation purposes (course, turn, horizon, cardinal indicators), for measuring angular orientation of moving objects and in many other cases (for example, when passing adit shafts, constructing subways, when drilling wells).

Classic gyroscope. According to the laws of Newtonian mechanics, the speed of rotation of the axis of a rapidly rotating symmetrical solid body in space is inversely proportional to its own angular velocity and, therefore, the gyroscopic axis rotates so slowly that at a certain time interval it can be used as an indicator of a constant direction in space.

The simplest gyroscope is a top, the paradoxical behavior of which lies in its resistance to changing the direction of the rotation axis. Under the influence of an external force, the axis of the top begins to move in a direction perpendicular to the force vector. It is thanks to this property that the rotating top does not fall, and its axis describes a cone around the vertical. This movement is called gyroscope precession. If a pair of forces (P, P'), P' = -P, is applied to the axis of a rapidly rotating free gyroscope, with a moment M = Ph, where h is the arm of the pair of forces (Fig. 1), then (contrary to expectation) the gyroscope will begin to rotate additionally not around the x-axis, perpendicular to the plane of the pair of forces, but around the y-axis, lying in this plane and perpendicular to the z-axis of rotation of the gyroscope. If at any point in time the action of a pair of forces stops, then precession will simultaneously stop, i.e. the precessional movement of the gyroscope is inertia-free. So that the axis of the gyroscope can rotate freely in space, the gyroscope is usually fixed in the rings of a gimbal (Fig. 2), which is a system of solid bodies (frames, rings) connected in series by cylindrical hinges. Usually, in the absence of technological errors, the axes of the gimbal frames intersect at one point - the center of the suspension. A symmetrical body of rotation (rotor) fixed in such a suspension has three degrees of freedom and can make any rotation around the center of the suspension. A gyroscope whose center of mass coincides with the center of the suspension is called balanced, astatic or free. Studying the laws of motion of a classical gyroscope is a problem of rigid body dynamics.

The main quantitative characteristic of the rotor of a mechanical gyroscope is its vector of its own kinetic moment, also called angular momentum or angular momentum,

where I is the moment of inertia of the gyroscope rotor relative to the axis of its own rotation, Ω is the angular velocity of the gyroscope’s own rotation relative to the axis of symmetry.

The slow movement of the vector of the gyroscope’s own angular momentum under the influence of moments of external forces, called precession of the gyroscope, is described by the equation

ω x Η = M, (2)

where ω is the vector of the angular velocity of precession, H is the vector of the gyroscope’s own angular momentum, M is the component of the torque vector of external forces applied to the gyroscope orthogonal to H.

The moment of forces applied from the rotor to the bearings of the axis of the rotor’s own rotation, which occurs when the direction of the axis changes and is determined by the equation

М g = -М = Η x ω, (3)

called gyroscopic moment.

In addition to slow precessional movements, the gyroscope axis can perform rapid oscillations with small amplitude and high frequency- so-called nutations. For a free gyroscope with a dynamically symmetrical rotor in an inertia-free suspension, the frequency of nutational oscillations is determined by the formula

where A is the moment of inertia of the rotor relative to an axis orthogonal to the axis of its own rotation and passing through the center of mass of the rotor. In the presence of frictional forces, nutational vibrations usually decay quite quickly.

The gyroscope error is measured by the speed at which its axis moves away from its original position. According to equation (2), the amount of drift, also called drift, is proportional to the moment of force M relative to the center of the gyroscope suspension:

ω х = М/Н (4)

The loss ω х is usually measured in degrees of arc per hour. From formula (4) it follows that a free gyroscope functions ideally only if the external moment M is equal to 0. In this case, the angular velocity of precession becomes zero and the axis of its own rotation will exactly coincide with the constant direction in inertial space.

However, in practice, any means used to suspend the gyroscope rotor causes unwanted external moments of unknown magnitude and direction. Formula (4) determines ways to increase the accuracy of a mechanical gyroscope: it is necessary to reduce the “harmful” moment of forces M and increase the kinetic moment N. When choosing the angular velocity of a gyroscope, it is necessary to take into account one of the main limitations associated with the strength limits of the rotor material due to centrifugal forces arising during rotation strength When the rotor accelerates above the so-called permissible angular velocity, the process of its destruction begins.

The best modern gyroscopes have a random drift of about 10 -4 -10 -5 °/h. The gyroscope axis, with an error of 10 -5 °/h, makes a full rotation of 360 ° in 4 thousand years! The gyroscope balancing accuracy with an error of 10 -5 °/h should be higher than one ten-thousandth of a micrometer (10 -10 m), that is, the displacement of the rotor center of mass from the center of the suspension should not exceed a value on the order of the diameter of a hydrogen atom.

Gyroscopic devices can be divided into power and measuring. Power devices serve to create moments of force applied to the base on which the gyroscopic device is installed; measuring ones are designed to determine the parameters of the movement of the base (the measured parameters can be the angles of rotation of the base, projections of the angular velocity vector, etc.).

The first time a balanced gyroscope found practical application was in 1898 in a device for stabilizing the course of a torpedo, invented by the Austrian engineer L. Aubry. Similar devices in various versions began to be used in the 1920s on airplanes to indicate heading (direction gyroscope, gyro-compasses), and later to control the movement of rockets. Figure 3 shows an example of using a gyroscope with three degrees of freedom in an aviation heading indicator (gyro-half-compass). The rotation of the rotor in ball bearings is created and supported by a stream of compressed air directed at the grooved surface of the rim. Using the azimuth scale attached to the outer frame, you can, by setting the axis of the rotor’s own rotation parallel to the plane of the device’s base, enter the required azimuth value. Friction in the bearings is insignificant, so the axis of rotation of the rotor maintains a given position in space. Using the arrow attached to the base, you can control the rotation of the aircraft on the azimuth scale.

The gyro horizon, or artificial horizon, which allows the pilot to maintain his aircraft in a horizontal position when the natural horizon is not visible, is based on the use of a gyroscope with a vertical axis of rotation that maintains its direction when the aircraft is tilted. Autopilots use two gyroscopes with horizontal and vertical axes of rotation; the first serves to maintain the plane's heading and controls the vertical rudders, the second - to maintain horizontal position aircraft and controls the horizontal rudders.

Using a gyroscope, autonomous inertial navigation systems (INS) have been created, designed to determine the coordinates, speed and orientation of a moving object (ship, plane, spacecraft, etc.) without using any external information. In addition to the gyroscope, the INS includes accelerometers designed to measure the acceleration (overload) of an object, as well as a computer that integrates the output signals of the accelerometers over time and provides navigation information taking into account the gyroscope readings. By the beginning of the 21st century, such accurate ANNs have been created that further increases in accuracy are no longer required to solve many problems.

The development of gyroscopic technology in recent decades has focused on the search for unconventional areas of application of gyroscopic devices - mineral exploration, earthquake prediction, ultra-precise measurement of the coordinates of railway tracks and oil pipelines, medical equipment and much more.

Non-classical types of gyroscopes. High demands on the accuracy and operational characteristics of gyroscopic devices have led not only to further improvements to the classic gyroscope with a rotating rotor, but also to the search for fundamentally new ideas to solve the problem of creating sensitive sensors for indicating and measuring the angular movements of an object in space. This was facilitated by the successes of quantum electronics, nuclear physics and other areas of the exact sciences.

An air-supported gyroscope replaces the ball bearings used in a traditional gimbal with a "gas cushion" (gas-dynamic support). This completely eliminated the wear of the support material during operation and made it possible to increase the service life of the device almost indefinitely. The disadvantages of gas supports include fairly large energy losses and the possibility of sudden failure if the rotor accidentally comes into contact with the support surface.

A float gyroscope is a rotary gyroscope in which, to unload the suspension bearings, all moving elements are weighed in a liquid with high density so that the weight of the rotor along with the casing is balanced by hydrostatic forces. Thanks to this, dry friction in the suspension axes is reduced by many orders of magnitude and the shock and vibration resistance of the device is increased. The sealed casing, which acts as the internal frame of the gimbal, is called a float. The gyroscope rotor inside the float rotates on an air cushion in aerodynamic bearings at a speed of about 30-60 thousand revolutions per minute. To increase the accuracy of the device, it is necessary to use a thermal stabilization system. A float gyroscope with high viscous fluid friction is also called an integrating gyroscope.

A dynamically tunable gyroscope (DTG) belongs to the class of gyroscopes with an elastic rotor suspension, in which the freedom of angular movements of the axis of its own rotation is ensured due to the elastic compliance of structural elements (for example, torsion bars). In the DNG, in contrast to the classic gyroscope, the so-called internal cardan suspension is used (Fig. 4), formed by an inner ring 2, which is attached from the inside by torsion bars 4 to the shaft of the electric motor 5, and from the outside by torsion bars 3 to the rotor 1. The frictional moment in the suspension is manifested only as a result of internal friction in the material of elastic torsion bars. In the DNG, due to the selection of the moments of inertia of the suspension frames and the angular speed of rotation of the rotor, the elastic moments of the suspension applied to the rotor are compensated. The advantages of DNGs include their miniature size, the absence of bearings with specific friction moments present in a classic gimbal suspension, high stability of readings, and relatively low cost.

Rice. 4. Dynamically adjustable gyroscope with internal gimbal suspension: 1 - rotor; 2 - inner ring; 3 and 4 - torsion bars; 5 - electric motor.

A ring laser gyroscope (RLG), also called a quantum gyroscope, is created on the basis of a laser with a ring resonator, in which counter-propagating electromagnetic waves simultaneously propagate along a closed optical circuit. The advantages of KLG include the absence of a rotating rotor, bearings exposed to friction forces, and high accuracy.

A fiber-optic gyroscope (FOG) is a fiber-optic interferometer in which counterpropagating electromagnetic waves propagate. FOG is an analog converter of the angular velocity of rotation of the base on which it is installed into an output electrical signal.

A solid-state wave gyroscope (SWG) is based on the use of the inert properties of elastic waves in a solid. An elastic wave can propagate in a continuous medium without changing its configuration. If standing waves of elastic vibrations are excited in an axisymmetric resonator, then the rotation of the base on which the resonator is installed causes the standing wave to rotate through a smaller but known angle. The corresponding movement of the wave as a whole is called precession. The rate of precession of a standing wave is proportional to the projection of the angular velocity of rotation of the base onto the axis of symmetry of the resonator. The advantages of VTG include: high accuracy/price ratio; ability to withstand heavy overloads, compactness and low weight, low energy intensity, short readiness time, weak dependence on ambient temperature.

A vibration gyroscope (VG) is based on the property of a tuning fork to maintain the plane of vibration of its legs. In the leg of an oscillating tuning fork mounted on a platform rotating around the axis of symmetry of the tuning fork, a periodic moment of force arises, the frequency of which is equal to the frequency of vibration of the legs, and the amplitude is proportional to the angular velocity of rotation of the platform. Therefore, by measuring the amplitude of the twist angle of the tuning fork leg, one can judge the angular velocity of the platform. The disadvantages of VG include instability of readings due to the difficulties of high-precision measurement of the amplitude of oscillations of the legs, as well as the fact that they do not work in conditions of vibration, which almost always accompanies the installation sites of devices on moving objects. The idea of ​​a tuning fork gyroscope stimulated a whole line of searches for new types of gyroscopes using the piezoelectric effect or vibration of liquids or gases in specially curved tubes and the like.

Micromechanical gyroscope (MMG) refers to low-precision gyroscopes (below 10 -1 °/h). This area has traditionally been considered unpromising for the problems of controlling moving objects and navigation. But at the end of the 20th century, the development of MMGs became one of the most intensively developed areas of gyroscopic technology, closely related to modern silicon technologies. An MMG is a kind of electronic chip with a quartz substrate with an area of ​​several square millimeters, onto which a flat vibrator such as a tuning fork is applied using photolithography. The accuracy of modern MMGs is low and reaches 10 1 -10 2 °/h, but the extremely low cost of micromechanical sensing elements is of decisive importance. Thanks to the use of well-developed modern technologies mass production of microelectronics opens up the possibility of using MMG in completely new areas: cars and binoculars, telescopes and video cameras, mice and joysticks personal computers, mobile robotic devices and even children's toys.

Non-contact gyroscope refers to ultra-high precision gyroscopic devices (10 -6 -5·10 -4 °/h). The development of a gyroscope with non-contact gimbals began in the mid-20th century. In non-contact gimbals, the state of levitation is realized, i.e., a state in which the gyroscope rotor “floats” in the force field of the gimbal without any mechanical contact with surrounding bodies. Among non-contact gyroscopes, gyroscopes with electrostatic, magnetic and cryogenic rotor suspensions are distinguished. In an electrostatic gyroscope, a conductive beryllium spherical rotor is suspended in an evacuated cavity in a controlled electric field created by a system of electrodes. In a cryogenic gyroscope, a superconducting niobium spherical rotor is suspended in a magnetic field; The working volume of the gyroscope is cooled to ultra-low temperatures, so that the rotor goes into a superconducting state. A gyroscope with a magnetic resonance suspension of the rotor is an analogue of a gyroscope with an electrostatic suspension of the rotor, in which the electric field is replaced by a magnetic field, and the beryllium rotor is replaced by a ferrite one. Modern gyroscopes with non-contact suspensions are highly complex devices that incorporate the latest technological advances.

In addition to the types of gyroscopes listed above, work has been and is being done on exotic types of gyroscope, such as ion gyroscope, nuclear gyroscope, etc.

Mathematical problems in gyroscope theory. The mathematical foundations of the theory of the gyroscope were laid by L. Euler in 1765 in his work “Theoria motus corporum solidorum sue rigidorum”. The motion of a classical gyroscope is described by a system of 6th order differential equations, the solution of which has become one of the most famous mathematical problems. This problem belongs to the section of the theory of rotational motion of a rigid body and is a generalization of problems that can be completely solved by simple means of classical analysis. However, it is so difficult that it is still far from completion, despite the results obtained by the greatest mathematicians of the 18th-20th centuries. Modern gyroscopic devices required solving new mathematical problems. The movement of non-contact gyroscopes obeys the laws of mechanics with high accuracy, therefore, by solving the equations of motion of a gyroscope using a computer, one can accurately predict the position of the gyroscope axis in space. Thanks to this, developers of non-contact gyroscopes do not have to balance the rotor with an accuracy of 10 -10 m, which is impossible to achieve with the current level of technology. It is enough to accurately measure the manufacturing errors of the rotor of a given gyroscope and introduce appropriate corrections into the gyroscope signal processing programs. The equations of motion of the gyroscope obtained taking into account these corrections turn out to be very complex, and to solve them it is necessary to use very powerful computers, using algorithms based on the latest advances in mathematics. The development of programs for calculating the movement of a gyroscope with non-contact gimbals can significantly increase the accuracy of the gyroscope, and therefore the accuracy of determining the location of the object on which these gyroscopes are installed.

Lit.: Magnus K. Gyroscope. Theory and application. M., 1974; Ishlinsky A. Yu. Orientation, gyroscopes and inertial navigation. M., 1976; Klimov D. M., Kharlamov S. A. Dynamics of a gyroscope in a gimbal suspension. M., 1978; Ishlinsky A. Yu., Borzov V. I., Stepanenko N. P. Lectures on the theory of gyroscopes. M., 1983; Novikov L.Z., Shatalov M.Yu. Mechanics of dynamically tuned gyroscopes. M., 1985; Zhuravlev V.F., Klimov D.M. Wave solid-state gyroscope. M., 1985; Martynenko Yu. G. Movement of a rigid body in electric and magnetic fields. M., 1988.

When you try to turn a spinning body, a force arises that acts perpendicular to the force you apply to it. In the second picture you can see that when the parts of the wheel, indicated by points A and B, are rotated 90 degrees, they tend to rotate the wheel clockwise in the plane of the screen. This is called precession. Because of this force, the axis of the top always moves in a circle, if it is not launched smoothly, very non-intuitive.

Let's dream about summer, imagine that we are riding a bike. We can clearly see the front wheel, almost from above. If we try to turn, for example, to the left, then we apply force to the wheel axis. Those parts of the wheel that are currently ahead are given an impulse directed to the left, and rear parts the wheel has an impulse to the right.

But, since we are driving fast and the wheel is spinning, the part that was just in front ends up behind, and the small impulse that we managed to give to this part of the wheel now works in the opposite direction and turns it in the opposite direction.

It turns out that due to the rotation of the wheel, we prevent ourselves from turning it. That is, the force that we apply to turn the wheel is returned to us after half a revolution of the wheel.

Any rotating object can be called a gyroscope. It counteracts the deviation of the rotation axis, and people actively use it:

In modern controllers game consoles And the iPhone 4 has gyroscopes, but they are designed on a completely different principle.

In navigation devices on airplanes and spacecraft. A well-balanced gyroscope on special hinges, installed on an airplane, always maintains its position in space; no aerobatics will knock it down. This allows the aircraft's instruments to always know which way is down.

In arms. The bullet twists when fired, which gives it much greater stability, which greatly increases shooting accuracy.

The wheels of a bicycle or motorcycle work like gyroscopes, and this prevents the rider from falling. It is more difficult to ride a bicycle slowly than quickly, because at high speed the wheels spin faster and make it more stable.

There are many toys where the main part is a gyroscope: all kinds of tops and yo-yos with which you can do the following tricks:

Gyroscope invented by Foucault (built by Dumolin-Froment, 1852)

Before the invention of the gyroscope, humanity used various methods for determining direction in space. Since ancient times, people have been guided visually by distant objects, in particular by the Sun. Already in ancient times, the first instruments appeared: a plumb line and a level based on gravity. In the Middle Ages, a compass was invented in China, using the magnetism of the Earth. In Europe, the astrolabe and other instruments were created based on the positions of the stars.

The advantage of the gyroscope over more ancient devices was that it worked correctly in difficult conditions (poor visibility, shaking, electromagnetic interference). However, the rotation of the gyroscope quickly slowed down due to friction.

In the second half of the 19th century, it was proposed to use an electric motor to accelerate and maintain the rotation of the gyroscope. The gyroscope was first used in practice in the 1880s by engineer Aubrey to stabilize the course of a torpedo. In the 20th century, gyroscopes began to be used in airplanes, rockets and submarines instead of or in conjunction with a compass.

Classification

Main types of gyroscopes by number of degrees of freedom:

• two-stage,
• three-degree.

There are two main types of gyroscopes based on their operating principle:

• mechanical gyroscopes,
• optical gyroscopes.

Mechanical gyroscopes

Among mechanical gyroscopes, it stands out rotary gyroscope- a rapidly rotating solid body (rotor), the axis of rotation of which can freely change orientation in space. In this case, the rotation speed of the gyroscope significantly exceeds the rotation speed of its rotation axis. The main property of such a gyroscope is the ability to maintain a constant direction of the rotation axis in space in the absence of the influence of moments of external forces on it and to effectively resist the action of external moments of forces. This property is largely determined by the angular velocity of the gyroscope's own rotation.

For the first time this property was used by Foucault in . It was thanks to this demonstration that the gyroscope got its name from the Greek words “rotation”, “observe”.

Properties of a three-degree rotor gyroscope

Precession of a mechanical gyroscope.

that is, it is inversely proportional to the rotation speed of the gyroscope.

Vibration gyroscopes

Vibrating gyroscopes are devices that maintain the plane of their vibrations when the base is rotated. This type of gyroscope is much simpler and cheaper with comparable accuracy compared to a rotary gyroscope. In foreign literature, the term “Coriolis vibration gyroscopes” is also used - since the principle of their operation is based on the effect of the Coriolis force, like rotary gyroscopes.
For example, vibration gyroscopes are used in the tilt measurement system of the Segway electric scooter. The system consists of five vibration gyroscopes, whose data is processed by two microprocessors.
It is this type of gyroscopes that is used in mobile devices, in particular, in the iPhone 4 and others.

Principle of operation

Two suspended weights vibrate on a plane in a MEMS gyroscope with a frequency of .

When the gyroscope turns, a Coriolis acceleration occurs equal to , where is the speed and is the angular frequency of the gyroscope rotation. The horizontal speed of the oscillating weight is obtained as: , and the position of the weight in the plane is . The out-of-plane motion caused by the rotation of the gyroscope is equal to:

where: is the mass of the oscillating weight.

- spring stiffness coefficient in the direction perpendicular to the plane.

- the amount of rotation in the plane perpendicular to the movement of the oscillating weight.

Varieties

Gyroscope at MAKS-2009

where is the difference in arrival times of rays released in different directions, is the contour area, and is the angular velocity of rotation of the gyroscope. Since the value is very small, its direct measurement using passive interferometers is possible only in fiber-optic gyroscopes with a fiber length of 500-1000 m. In a rotating ring interferometer of a laser gyroscope, the phase shift of counterpropagating waves can be measured equal to:

where is the wavelength.

Application of gyroscopes in technology

Diagram of a simple mechanical gyroscope in a gimbal

The properties of a gyroscope are used in devices - gyroscopes, the main part of which is a rapidly rotating rotor, which has several degrees of freedom (axes of possible rotation).

The most commonly used are gyroscopes placed in gimbals. Such gyroscopes have 3 degrees of freedom, that is, it can make 3 independent rotations around its axes AA", BB" And CC", intersecting in the center of the suspension ABOUT, which remains relative to the base A motionless.

Stabilization systems

Stabilization systems come in three main types.

• System force stabilization(on two-stage gyroscopes).

One gyroscope is needed for stabilization around each axis. Stabilization is carried out by a gyroscope and an unloading motor, at the beginning the gyroscopic moment acts, and then the unloading motor is connected.

• Indicator-power stabilization system (on two-step gyroscopes).

One gyroscope is needed for stabilization around each axis. Stabilization is carried out only by unloading engines, but at the beginning a small gyroscopic moment appears, which can be neglected.

• Indicator stabilization system (on three-degree gyroscopes)

To stabilize around two axes, one gyroscope is needed. Stabilization is carried out only by unloading motors.

New types of gyroscopes

Constantly growing requirements for the accuracy and performance characteristics of gyro-devices have forced scientists and engineers from many countries around the world not only to improve classic gyroscopes with a rotating rotor, but also to look for fundamentally new ideas that solve the problem of creating sensitive sensors for measuring and displaying the parameters of the angular motion of an object.

Currently known more than a hundred various phenomena and physical principles that allow solving gyroscopic problems. In Russia and the USA, thousands of patents and copyright certificates have been issued for relevant discoveries and inventions.

Because precision gyroscopes are used in the guidance systems of long-range strategic missiles, information about research conducted in this area was classified as classified during the Cold War.

The direction of development of quantum gyroscopes is promising.

Prospects for the development of gyroscopic instrumentation

Today, fairly accurate gyroscopic systems have been created that satisfy a wide range of consumers. The reduction of funds allocated for the military-industrial complex in the budgets of the world's leading countries has sharply increased interest in the civilian applications of gyroscopic technology. For example, today the use of micromechanical gyroscopes in car stabilization systems or video cameras is widespread.

According to supporters of navigation methods such as GPS and GLONASS, outstanding progress in the field of high-precision satellite navigation has made autonomous navigation aids unnecessary (within the coverage area of ​​​​the satellite navigation system (SNS), that is, within the planet). Currently, SNS systems are superior to gyroscopic systems in terms of weight, dimensions and cost.

Currently being developed third generation navigation satellite system. It will allow you to determine the coordinates of objects on the Earth's surface with an accuracy of several centimeters in differential mode, when located in the coverage area of ​​the DGPS correction signal. In this case, there is supposedly no need to use directional gyroscopes. For example, installing two satellite signal receivers on the wings of an airplane allows you to obtain information about the rotation of the airplane around a vertical axis.

However, SNS systems are unable to accurately determine position in urban environments with poor satellite visibility. Similar problems are found in wooded areas. In addition, the passage of SNS signals depends on processes in the atmosphere, obstacles and signal reflections. Autonomous gyroscopic devices work anywhere - underground, underwater, in space.

In airplanes, the SNS turns out to be more accurate than the INS long areas. But using two SNS receivers to measure aircraft inclination angles gives errors of up to several degrees. Calculating the course by determining the speed of the aircraft using SNS is also not accurate enough. Therefore, in modern navigation systems, the optimal solution is a combination of satellite and gyroscopic systems, called an integrated (complex) INS/SNS system.

Over the past decades, the evolutionary development of gyroscopic technology has approached the threshold of qualitative changes. That is why the attention of specialists in the field of gyroscopy is now focused on finding non-standard applications for such devices. Completely new interesting tasks have opened up: geological exploration, earthquake prediction, ultra-precise measurement of the positions of railways and oil pipelines, medical equipment and many others.

Using a gyroscope in smartphones and game consoles

IPhone 4 with gyroscope inside

Significant reduction in the cost of production of MEMS gyroscopes has led to their use in smartphones and game consoles.

Also gyroscope began to be used in control game controllers, such as: Sixaxis for Sony PlayStation 3 and Wii MotionPlus for Nintendo Wii. Both of these controllers use two complementary spatial sensors: an accelerometer and gyroscope. For the first time, a game controller that can determine its position in space was released by Nintendo - Wii Remote for the Wii game console, but it only uses a three-dimensional accelerometer. A 3D accelerometer is not capable of accurately measuring rotational parameters during highly dynamic movements. And that is why in the latest game controllers: Sixaxis and Wii MotionPlus, in addition to the accelerometer, an additional spatial sensor was used - gyroscope.

Gyroscope based toys

The most simple examples toys made on the basis of a gyroscope are yo-yo, spinning top (spinning top) and helicopter models.
Tops differ from gyroscopes in that they do not have a single fixed point.
In addition, there is a sports gyroscopic simulator.

see also

Notes

1. Johann G. F. Bohnenberger (1817) “Beschreibung einer Maschine zur Erläuterung der Gesetze der Umdrehung der Erde um ihre Axe, und der Veränderung der Lage der letzteren” (“Description of a machine to explain the laws of the rotation of the Earth around its axis and the change in direction of the latter”) Tübinger Blätter für Naturwissenschaften und Arzneikunde, vol. 3, pages 72-83. On the Internet: http://www.ion.org/museum/files/File_1.pdf
2. Simeon-Denis Poisson (1813) “Mémoire sur un cas particulier du mouvement de rotation des corps pesans” (“Article on the special case of rotational motion of massive bodies”), Journal de l'École Polytechnique, vol. 9, pages 247-262. On the Internet: http://www.ion.org/museum/files/File_2.pdf
3. Photo of Bonenberger's gyroscope: http://www.ion.org/museum/item_view.cfm?cid=5&scid=12&iid=24
4. Walter R. Johnson (January 1832) "Description of an apparatus called the rotascope for exhibiting several phenomena and illustrating certain laws of rotary motion," The American Journal of Science and Art, 1st series, vol. 21, no. 2, pages 265-280. On the Internet: http://books.google.com/books?id=BjwPAAAAYAAJ&pg=PA265&lpg=PR5&dq=Johnson+rotascope&ie=ISO-8859-1&output=html
5. Illustrations of Walter R. Johnson's gyroscope (“rotascope”) appear in: Board of Regents, Tenth Annual Report of the Board of Regents of the Smithsonian Institution….(Washington, D.C.: Cornelius Wendell, 1856), pages 177-178. On the Internet: http://books.google.com/books?id=fEyT4sTd7ZkC&pg=PA178&dq=Johnson+rotascope&ie=ISO-8859-1&output=html
6. Wagner JF, "The Machine of Bohnenberger," The Institute of Navigation. On the Internet: http://www.ion.org/museum/item_view.cfm?cid=5&scid=12&iid=24
7. L. Foucault (1852) "Sur les phénomènes d'orientation des corps tournants entraînés par un axe fixe à la surface de la terre," Comptes rendus hebdomadaires des séances de l’Académie des Sciences (Paris), vol. 35, pages 424-427. On the Internet: http://www.bookmine.org/memoirs/pendule.html. Scroll down to “Sur les phénomènes d’orientation...”
8. (1) Julius Plücker (September 1853) "Über die Fessel'sche rotationsmachine," Annalen der Physik, vol. 166, no. 9, pages 174-177; (2) Julius Plücker (October 1853) "Noch ein wort über die Fessel'sche rotationsmachine," Annalen der Physik, vol. 166, no. 10, pages 348-351; (3) Charles Wheatstone (1864) "On Fessel's gyroscope," Proceedings of the Royal Society of London, vol. 7, pages 43-48. In the Internet: .