What is Gyroscope: Definition and 172 Discussions

A gyroscope (from Ancient Greek γῦρος gûros, "circle" and σκοπέω skopéō, "to look") is a device used for measuring or maintaining orientation and angular velocity. 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.
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 lasers, fibre optic gyroscopes, and the extremely sensitive quantum gyroscope.Applications of gyroscopes include inertial navigation systems, such as in the Hubble Telescope, or inside the steel hull of a submerged submarine. Due to their precision, gyroscopes are also used in gyrotheodolites to maintain direction in tunnel mining. Gyroscopes can be used to construct gyrocompasses, 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.

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  1. Malwina

    Minimal rotational kinetic energy for a gyroscope to precess

    TL;DR Summary: I cannot find any information on how to calculate min. KErot at which the gyroscope does not fall over I am doing a project for school in which I investigate energy loss in a gyroscope. I apply a torque on a gyroscope to initiate its rotation and then measure the time it takes...
  2. J

    I Why do bullets precess in the opposite way from gyroscope diagrams?

    1) Bullet spin causes a bullet to become a gyroscope. Specifically, bullets have their center of pressure in front of their center of mass. Therefore, when pressed, gyroscopic forces cause a bullet to spin 90 degrees instead of tumble. See this diagram: 2)The precession does not cause the...
  3. P

    I PIGA: Pendulous Integrating Gyroscopic Accelerometer

    Wiki describes the PIGA, https://en.wikipedia.org/wiki/PIGA_accelerometer. I want to see if I have a basic intuitive understanding of how it works. https://en.wikipedia.org/wiki/PIGA_accelerometer#/media/File:PIGA_accelerometer_1.png Lets imagine that the device, as shown, is at rest on the...
  4. KDP

    I Sagnac gyroscope affected by linear acceleration?

    As some of you know I have been coding a 2+1D relativistic simulator that can handle (constant proper) acceleration in any direction on a plane. So far it is going quite well. I have now decided to simulate a Sagnac gyroscope inside the simulation by sending signals in opposite directions...
  5. T

    A Trig functions and the gyroscope

    Good Morning As I continue to study the gyroscope with Tait-Bryan angles or Euler angles, and work out relationships to develop steady precession, I notice that the trig functions cancel. I stumble on terms like: 1. sin(theta)cos(theta) - cos(theta)sin(theta) 2. Cos_squared +...
  6. Kumail Haider

    Applications of gyroscope in daily life

    Hello! I was just started the topic gyroscopic motion These questions come to my mind. please guide me that how gyroscope is used in mobiles what is its function in mobiles and also want to know their role in aircrafts that how it helps pilot to determine the position of aircraft etc. Please...
  7. Z

    I Can a Gyroscope on a Satellite Detect Orbit?

    Einstein said, when describing someone falling off a building, that the Earth accelerating up to meet him/her. Without the Earth getting larger in all directions as the paradox goes, it curvature of space-time which is why you can have the acceleration up without the surface moving up as you...
  8. cianfa72

    I Definition of "Spatial X Direction" in Spacetime Context

    Hi, although there is a lot of discussion here in PF, I'd like to ask for a clarification about the definition of 'spatial x direction' in the context of flat or curved spacetime. Consider a set of free-falling gyroscopes (zero proper acceleration) passing through an event A with different...
  9. HakimTem

    I Apparent Initial Acceleration due to Precession of Wheel Gyroscope?

    The center of mass of a system is defined as a point that acts as if all the mass is concentrated on that one point whereby all forces may act on it. With a wheel gyroscope as an example where the center of mass is in the middle of the wheel when the wheel is spun and let go, the wheel undergoes...
  10. A

    I Precession of a gyroscope in freefall

    Imagine I have the following gyroscope: This gyroscope has been spun up with significant angular momentum and rests on a platform below it. It's offset at an angle and so I've drawn the R vector from the axis of rotation. So the only force being applied right now is gravitational force...
  11. SpaceThoughts

    I Will the spinning gyroscope make the plumb fall slower?

    When winding a bike wheel up in an elastic double string in the ceiling, and then let the wheel spin vertically, it unwinds more slowly than if it was not spinning. I tried it. But it if a spinning disk is placed in a solid construction like this (photo attached) , and can only rotate...
  12. SpaceThoughts

    I How to calculate gyroscopic inertia this setup?

    This text refers to the photo below. The wheel in the middle can rotate vertically without friction. The construction around it can rotate the wheel horizontally as well, also without friction. When the blue weight is falling while the wheel is not rotating, I can calculate the kinetic energi...
  13. curiousPep

    I Solving Euler's Dynamics Equations for a Gyro-Compass

    Hello, I know it might sound silly but sometimes I get confused. Let's say I have a gyro-compass and I get 3 equations of torque for the 3 axes. I am expected to find the equation of motion and two of them are equated with 0. These are the Euler's dynamics equation with moving reference frame...
  14. T

    A What happens first: precession or nutation?

    Good Morning Suppose, for the sake of this question, the following Euler rotations for a gyroscope) A precession about the vertical 3-axis (like with a top, going around a vertical) Then, a nutation (a leaning over) about the 1-axis Then, back to the spin itself of the top body about the...
  15. Homestar1

    B Electron angular momentum, gyroscope?

    Any spinning item, proton, electron, even planet, has angular momentum that creates force. How can an electron exist in a random orbital cloud around a spinning proton if it has an angular momentum and requires force to alter from any circular orbital plane (like a planet orbiting a star)?
  16. S

    Can a gyroscope lift a fulcrum (and itself), hinged to the floor?

    This is a purely experimental idea which I would like some help understanding A) whether it can work and B) how best to understand the mechanics of the act. Firstly, my limited understanding of gyroscopes is that a stable gyroscope will (effectively) attempt to remain at the same angle if it is...
  17. HarryLime

    Accelerometer vs. Gyroscope - measuring torque

    Summary:: accelerometer Vs gyroscope - measuring torque Torque can be measured with an accelerometer (tangential-acceleration): t = F*r and F=m*a, so we get a from the accelerometer, giving: t = m*a*r Nm Torque can be measured with an gyroscope (angular-acceleration): t = F*r The...
  18. Leo Liu

    The angle of tilt of a gyroscope

    Problem Solution My question For the torque equation, I calculated the torque of the wheel at the point at the upper end of the string L' and wrote ##\dot{\vec L_x}=\tau_x=-Mg(l+L\sin\beta) \text{[the direction of x is out of paper]}## rather than the equation highlighted by green colour...
  19. richengle

    What is the minimum gyroscope speed to yield force precession?

    Does anyone know what the minimum speed of a gyro to make it so a force at 0deg will yield a movement at 90deg... or even better, what the angle is wrt speed... see http://www.copters.com/aero/gyro.html for pictures. -thx, rich
  20. F

    I Gyroscope, Gimbals Frame, lack of precession

    Hello, A simple gyroscope, which is nothing but a spinning top, will exhibit precessional motion if a) it spins and b) a nonzero gravitational torque is applied to it. The tip of the gyroscope rotates while the tip rotates on itself. If the gyroscope is mounted on gimbals, which are rings, the...
  21. andyonassis

    Gyroscope (Coriolis Torque and Force)

    I know that to prove the total coriolis torque from the coriolis torque on a point mass is to express dm as a function of ##d\theta## and integrate from 0 to ##2\pi## and then the x component disappears due to orthogonality of sine and cosine. But i am stuck at other parts.
  22. Like Tony Stark

    Reaction forces on a gyroscope

    I know that ##\vec{v_c}=(\omega_1;-\omega_2;0)×(L;-r;0)=0## So ##\omega_2=\frac{r\omega_1}{L}## Then, using the system of coordinates shown in the picture and ##\Sigma M_z## I can find the reaction force in ##C##. But how can I find the reaction forces on ##A## and ##O##? I mean, what system...
  23. J

    Why is there angular acceleration in a non-spinning gyroscope?

    I was watching the above video which is part of a series explaining the mechanics behind a gyroscope. In the video the author explains the mechanics of the gyroscope when stationary (the disc is not rotating). Here he derives a result that the angular acceleration is g/r which is non zero...
  24. LCSphysicist

    Kleppner 7.10 — Using a gyroscope to measure latitude

    I am not sure about a, but i think as long as there is no torque about the Lp direction, it will remain constant with relation to the polar star. I would like help in proof this mathematically. I just don't know how to proceed, i wonder if i would need to consider the torque provide by...
  25. D

    I Steady precession of a gyroscope

    Hi I am trying to understand the concept of why a gyroscope that is not spinning drops down but when it is spinning then it precesses. I have looked in "University Physics" by Young + Freedman and Kleppner , Morin and Gregory but i am not getting anywhere. Does anyone know of a relatively simple...
  26. rzyn

    Rotation and effective gravity on Earth

    I'm interested in calculating effective gravity for a point-mass in a spinning gyro or swinging pendulum bob on a rotating planet undergoing any translational velocities and/or accelerations. I want to investigate the theoretical effects of high-energy mechanical oscillation on orbital...
  27. T

    Angular Momentum Vector and Torque Vector

    In studying gyroscopic progression, the angular momentum vector is added to the torque vector. As intuitively these two vectors seem to be qualitatively quite different, how do we know that both vectors are in the same vector field and that they can be manipulated using the rules of vector...
  28. D

    Resistance and Precession Torque of a Gyroscope

    Hi, Say there's a gyroscope with moments of inertia Ix, Iy and Iz spinning around a vertical z-axis (see attached illustration) with a given angular velocity ωz. Notice that the gyroscope is floating in space as in that there's no gravity acting on the gyroscope. Now I apply a torque τx...
  29. Z

    Difference between gyroscope angular displacement and Euler angles

    Hi guys, I'm trying to understand between gyroscope angular displacement and euler angles? for example { Δx = Δx + h * Rx * SCx);} this is gyroscope output about anguler displacement.This value can be used to determine angle that device created.Why we should euler angles to fly.(I know...
  30. N

    B Does a gyroscope bend spacetime?

    I've tried to find the answer to this but I can't I know what we experience as gravity is the bending of space by the mass of the Earth. But, a gyroscope is able to defy the Earths bending of space. Does a gyroscope on a small scale bend space perpendicular to the Earths bending and that's why...
  31. E

    I How do three flywheels, one in each axis, behave?

    I have been struggling to visualize how three rotating reaction wheels on bearings and affixed to each other at 90 degree angles, one at each axis (picture the kind of 3-axis reaction devices used in satalites), would behave when torque is applied to the whole assembly. If all three reaction...
  32. alan123hk

    B Simple derivation of the Equations of a Gyroscope

    Frankly, it is difficult for me to understand the derivation of mathematical equations that describe and explain the motion behavior of a gyroscope, particularly the reason why it spins in one direction, gravity tries to rotate it in a second direction, but it actually ends up turning in the...
  33. T

    Can someone explain to me gyroscopic stiffening and softening

    hi, I’m trying to understand why in a rotor bearing system that the critical speeds of the rotor are higher for forward whirl, and lower for backward whirl. My general understanding is that forward and backward whirl frequencies diverge due to gyroscopic effects, and for forward whirl the...
  34. G

    Why is the Gödel Universe Rotating

    Homework Statement Consider the Godel Metric in spherical coordinates as on page 6 here; ds^2=4a^2\left[-dt^2+dr^2+dz^2-(\sinh^{4}(r)-\sinh^{2}(r))d\phi^2+2\sqrt{2}\sinh^{2}(r)dt d\phi)\right] This is a solution to Einstein's Equations if we have ##a=\frac{1}{2\sqrt{2\pi\rho}}## and ##\Lambda...
  35. Luigi Fortunati

    The gyroscope and its ability to avoid "falling down"

    The feature of the gyroscope is its ability to prevent the falling down of an object that rotates. Only a force directed upward can oppose a downward force. In the case of the spinning slingshot, we see that the stone tends to go up when the angular velocity increases. To identify the force...
  36. JTC

    Gyroscopic Water Wave Energy Converters

    Say I have a disk spinning in a buoy. Let me say the spin axis is vertical to the flat surface of the buoy (or sea if there were no waves). Now along comes a wave (that will induce a "precession" of the disk/buoy. The axis of this precession is from "starboard to port." This would induce...
  37. T

    Gyroscope Experiment Homework: Find Centre of Gravity & Nutation Effects

    Homework Statement Ok so in my lab we have been given a set-up as shown below Minus the horse shoe dector on the right hand side. During this set-up up we need to find the point where the balance point and centre of gravity are equal (as I understand) here is exactly what my script say...
  38. JTC

    Calculating power from a prescribed rotation

    Hi, Forgive me for this trivial question. I am confused. Let's say I have a gyroscopic device in which the rotor is set to spin at a prescribed angular velocity. Next, put it on an ocean surface in which the ocean waves induce a precession. These two rotations, then induce a moment (induce a...
  39. L

    Gyroscope precession compensation questions

    Hello I was watching some videos about gyroscopes and inertial guidance. In one of the videos lecturer said that rotating gyroscope set in one direction on gimbal will be pointing one direction and stay like this virtually forever, so we can use it for guidance system. However I read more...
  40. A

    Mechanical gyroscopes -- still used in airplanes?

    I was a bit unsure where to post this, but this one seemed fitting enough. I was wondering about the state of gyros in airplanes, like which type is being used today. Are they all optik/fiber-based or are there mechanical gyroscopes at work. (By mechanical i mean the standard spinning wheel, not...
  41. G

    How Can I Relate Measurements from a Gyroscope and Accelerometer?

    Hi Physics Forums, I have two sensors that I am trying to relate: - One gyroscopes measuring angle - Two accelerometer measuring linear speed I have put the gyroscope in the middle of a long rectangular tube. While the accelerometers are at each end of this tube. I need help getting started...
  42. A

    I How Does a Clockwise Spinning Gyroscope Stay Upright?

    So I've just started reading into how gyroscopes work and I've hit a wall. Previously I thought that the upwards angular momentum kept the spinning object up straight, but why does it do the same if it's spinning clockwise too even though the angular momentum would be pointing down? Does the...
  43. TomVu

    Finding torque from gyroscopic effect

    Hello everyone, I have a problem while calculate dynamic for gyroscope system on bicycle. I use Lagrange's equation for modelling precession effect, with generalized coordinate is a angular, the applied generalized force will be a torque. The model of gyroscope system like picture below: I've...
  44. T

    I Gyroscopic Precession: Understanding the Physics

    I was watching this and I get it that when you rotate the wheel, the torque due to its weight will cause it to revolve parallel to the ground instead of perpendicular to the ground. I know that the faster you spin the wheel, the less likely the lever from the wheel to the pivot will be slanted...
  45. D

    Why Does My Car's Fuel Gauge Show False Readings on Hills?

    hello i am new here. I am facing a problem in fuel gauge that when i drive for a long time on hills it start to show false value. I decided to solve this problem i have a gyro and known resistance from fuel tank of my car and now i want to have true value all the time please help me with it or...
  46. M

    A gyroscope as weight for a lever

    if i got a beam of 40 meters and one side (35m) is 12 metric ton how do i calculate the forces on the gyroscope. I tried to caclutate it but i just get a torque and a angular momentum, how do i converted torque and angelur momenten in Netwons?
  47. A

    Can a CMG System Help Create a Self-Balancing Bicycle with Dual Flywheels?

    I want to build a Self Balancing autonomous bicycle for which I need to know about CMG System,Can Any one please guide me to the basics of Gyroscope and CMG- Ebooks would be a great starts.
  48. J

    I 2 Questions About the Gyroscope Effect

    I'm talking here about this situation: The explanation which is usually given as to why there is a precession, is that the torque is perpendicular to the angular momentum and the angular momentum changes in the direction of the torque. A few things I don't understand about it: 1. The torque is...
  49. B

    NASA's experiment with a gyroscope featured in Fabric of the Cosmos

    In Brian Greene's documentary The Fabric of the Cosmos, the thesis of the documentary is that empty space has physical properties even if there are no atoms or molecules in it. As I recall, most of the documentary shows the story of how NASA had a goal of sending a gyroscope up into space to...