Ex.II 1-c; 2-b; 3-a;

III. Match the words with their Ukrainian equivalents. Then decide which terms describe the pictures given below and how they relate the gyroscopes.

1. torsion	a. коливатися
2. tuning fork	b. зношування
3. oscillate	c. з’єднання
4. sensitivity	d. крутіння
5. capacitive	e. можливий
6. feasible	f. зубець
7. voltage	g. чутливість
8. junction	h. напруга
9. tine	i. ємкісний
10. wear	j. камертон

Ex. II 1- d; 2- j; 3-а; 4- g; 5-і; 6-е; 7- h; 8-с; 9- f;10- b;

1. 2. 3.

4. 5. 6.

1-capacitive; 2- oscillate; 3-wear; 4-junction; 5-torsion; 6-tuning fork;

IV. Read and translate the text then complete the table about the types of gyroscopes mentioned in the text.

Type of gyroscope	Function Field of aqpplication	Structure	Advantages and disadvatages
1.optical gyroscopes(Ring Laser)	in aeronautics and military applications.	lasers	no wear, greater reliability smaller size and weight.
2. Tuning Fork Gyroscope	the automobile industry. functioned as the yaw rate sensor for skid control in аnti-lock braking applications.	two tines connected to a junction bar which resonate at certain amplitude.
3.Piezoelectric Plate Gyroscope			simple in its design. smaller size
4.

Gyroscope

Technically, a gyroscope is any device that can measure angular velocity. As early as the 1700‘s, spinning devices were being used for sea navigation in foggy conditions. The more traditional spinning gyroscope was invented in the early 1800‘s, and the French scientist Jean Bernard Leon Foucault coined the term gyroscope in 1852. In the late 1800‘s and early 1900‘s gyroscopes were patented for use on ships. Around 1916, the gyroscope found use in aircraft where it is still commonly used today. Throughout the 20th century improvements were made on the spinning gyroscope. In the 1960‘s, optical gyroscopes using lasers were first introduced and soon found commercial success in aeronautics and military applications. In the last ten to fifteen years, MEMS gyroscopes have been introduced and advancements have been made to create mass-produced successful products with several advantages over traditional macro-scale devices.

Gyroscopes function depends on their type. Traditional spinning gyroscopes work on the basis that a spinning object tilted perpendicularly to the direction of the spin will have a precession. The precession keeps the device oriented in a vertical direction so the angle relative to the reference surface can be measured. Optical gyroscopes are most commonly ring laser gyroscopes. These devices send two lasers around a circular path in opposite directions. If the path spins, a phase shift can be detected since the speed of light always remains constant. Usually the rings are triangles or rectangles with mirrors at each corner. Optical gyroscopes are a great improvement to the spinning mass gyroscopes because there is no wear, greater reliability and smaller size and weight. Even after the introduction of laser ring gyroscopes, a lot of properties were desired. MEMS vibrating mass gyroscopes aimed to create smaller, more sensitive devices. The two main types of MEMS gyroscope are the tuning fork gyroscope and the vibrating ring gyroscope.

Draper Tuning Fork Gyroscope: One of the most widely used micro-machined gyroscopes is the tuning fork design from the Charles Stark Draper Lab. The design consists of two tines connected to a junction bar which resonate at certain amplitude. When the tines rotate, Coriolis force causes a force perpendicular to the tines of the fork. The force is then detected as bending of the tuning fork or a torsional force. These forces are proportional to the applied angular rate, from which the displacements can be measured in a capacitive fashion. Electrostatic, electromagnetic, or piezoelectric mechanisms can be used to detect the force. Since the development of their first tuning fork gyroscope in 1993, the Draper Laboratory has made significant improvements to the device. Their first gyroscope was developed for the automobile industry. The gyroscope had command of 1 degree/hr drift, and possessed 4000 deg/hr resolution. These devices eventually functioned as the yaw rate sensor for skid control in аnti-lock braking applications.

Piezoelectric Plate Gyroscope: While vibrating ring gyroscopes and tuning fork gyroscopes were the first successful MEMS gyroscopes and are still the most widely produced, other successful MEMS gyroscopes have since been created. One of these gyroscopes is the Piezoelectric Plate Gyroscope which uses a PZT plate as its base. This method, which in the past has been used to build macro-scale gyroscopes, is actually ideal for micro devices. At micro levels, an entire plate can be made of piezoelectric material. It has advantages over the common vibrating gyroscopes in that it requires a much smaller drive voltage to create readable outputs. The piezoelectric plate gyroscope is very simple in its design. In fact, it is much simpler than the ring or fork gyroscopes. There is a piezoelectric plate, which has a length and width much larger than its depth. Like other MEMS gyroscope the piezoelectric plate gyroscope works on the principle of a vibrating body. In this case, the vibrating body is a piezoelectric sheet. The sheet does not vibrate like a plate or fork. Instead the thickness vibrates which oscillates with time.

The piezoelectric plate gyroscope is a feasible alternative to traditional MEMS gyroscopes. One of its advantages is a lower required drive voltage. However, the sensitivity is only 38 microvolts, whereas the sensitivity of a ring gyroscope is around 200 microvolts. Also, when there is no rotation, traditional gyroscopes come much closer to the ideal zero volts output than the piezoelectric plate gyroscope, which still outputs up to 100 millivolts. A major advantage and the one that could prove most practical is the versatility of the piezoelectric plate gyroscope. It can measure rotation in two directions. In addition, if the driving voltage direction is switched, the same device can measure rotation in the third direction, although with much less sensitivity. Since this device is easily incorporated into other IC chips, it could be controlled to do more things than a ring or tuning fork gyroscope, which require three gyroscopes to measure three rotation directions.