Posted by on Aug 26, 2017 in Tell Me Why Numerous Questions and Answers |

# When Was the Gyroscope Invented?

Any spinning object resists attempts to change the direction of its axis, the imaginary straight line round which it revolves. Thus you can move a gyroscope up, down, forwards, sideways or backwards and feel no resistance, but you will meet opposition if you try to turn it through an angle. The gyroscope’s other important characteristic is called “precession”. This means that when you do overcome the resistance and push the axis out of the straight, the gyroscope does not tilt the way you push it but at right angles to the push and axis.

The peculiar qualities of gyroscopes have been exploited in complex instruments used for stabilizing purposes at sea, on land and in the air. They are used in the compasses, gun sights, and instruments for ships and aircraft. The first gyroscope was made in about 1817 by a German, G. C. Johann Bohnenberger. But the name was the idea of a French physicist, Léon Foucault, in 1852 when he used the device to demonstrate the rotation of the earth. It comes from two Greek words gyros, meaning “turn” or “revolution”, and skopein, meaning “to view”. Therefore gyroscope means “to view the turning”.

In 1832, American Walter R. Johnson developed a similar device that was based on a rotating disc. The French mathematician Pierre-Simon Laplace, working at the École Polytechnique in Paris, recommended the machine for use as a teaching aid. This instrument is based on the principle of a spinning top which remains upright in resistance to the force of gravitation as long as it keeps revolving. In a gyroscope a wheel is mounted in such a manner that it is free to revolve round any axis. When rotating the wheel gives its framework the same tendency to remain at the angle at which it is placed as a top has when it is spinning alone.

Essentially, a gyroscope is a top combined with a pair of gimbals. 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 Serson in 1743. It was used as a level, to locate the horizon in foggy or misty conditions.

In the 1860s, the advent of electric motors made it possible for a gyroscope to spin indefinitely; this led to the first prototype heading indicators, and a rather more complicated device, the gyrocompass. The first functional gyrocompass was patented in 1904 by German inventor Hermann Anschütz-Kaempfe. American Elmer Sperry 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 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 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 systems for ballistic missiles.

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 3 ounces (85 g) and had a diameter of approximately 1 inch (2.5 cm). 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 {\displaystyle 10^{-7}}of an inch would be required. Three-axis MEMS-based gyroscopes are also being used in portable electronic devices such as tablets, smartphones, and smartwatches. This adds to the 3-axis acceleration sensing ability available on previous generations of devices.

Together these sensors provide 6 component motion sensing; acceleration for X,Y, and Z movement, and gyroscopes for measuring the extent and rate of rotation in space (roll, pitch and yaw). Some devices (e.g. the iPhone) additionally incorporate a magnetometer 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.

Content for this question contributed by Diebra Bohnenkamper, resident of Cincinnati, Hamilton County, Ohio, USA