Text b Technical Parameters of Robots

• Number of axes– two axes are required to reach any point in a plane; three axes are required to reach any point in space.

• Degrees of freedomwhich is usually the same as the number of axes.

• Working space– the region of space a robot can reach.

• Kinematics– the actual arrangement of rigid members and joints in the robot, which determines the robot's possible motions.

• Carrying capacity or payload – how much weight a robot can lift.

• Speed– how fast the robot can position the end of its arm. This may be defined as angular or linear speed of each axis or a compound speed when all axes are moving.

• Acceleration- how quickly the movement along an axis accelerates.

• Accuracy– how closely a robot can reach a commanded position. Accuracy can vary with speed and payload (see compliance).

• Repeatability- how well the robot will return to a programmed position.

• Motion control– for some applications, such as simple pick-and-place assembly, the robot need merely return repeatedly to a limited number of positions. For more sophisticated applications, such as welding, the orientation and velocity of motion must be continuously controlled.

• Power source– some robots use electric motors, others use hydraulic actuators. The former are faster, the latter are stronger and advantageous in applications such as spray painting, where a spark could set off an explosion.

• Drive – some robots connect electric motors to the joints via gears; others connect the motor to the joint directly (direct drive).

• Compliance- this is a measure of the amount in angle or distance that a robot axis will move when a force is applied to it. Because of compliance when a robot goes to a position carrying its maximum payload it will be at a position slightly lower than when it is carrying no payload.

Задания к тексту B:

I. Найдите в тексте английские эквиваленты следующим русским выражениям:

угловая или линейная скорость каждой оси; источник питания; рабочая область; ускорение; приводная система; количество осей; несущая нагрузка; повторяемость; управление движением; степени свободы; точность; возможные движения робота; согласованность.

II. Сформулируйте в нескольких словах содержание каждого абзаца.

III. Напишите резюме к тексту.

IV. Ответьте на вопросы:

1. What are technical parameters of robots?

2. Can you give some examples of the robot’s parameters?

3. How many axes are necessary for a robot to reach any point in space?

4. Is the freedom degree parameter the same as the parameter of the number of axes?

5. Which parameter is responsible for weight a robot can lift?

6. How can a robot’s speed parameter be defined?

7. What is a difference between accuracy, repeatability and compliance?

V. Перескажите текст, используя в качестве плана вопросы предыдущего упражнения.