Robotics

A real industrial robot

With SIX revolute jointsA revolute joint has ONE degree of freedom ( 1 DOF) that is

defined by its angle

1

23

4

There are two more joints on the end effector (the

gripper)

“Robot” coined by Karel Capek in a 1921 science-fiction Czech play

“A robot is a reprogrammable, multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks.” (Robot Institute of America)

Definition:

Alternate definition:

“A robot is a one-armed, blind idiot with limited memory and which cannot speak, see, or hear.”

MIT’s Kismet: a robot which exhibits expressions, e.g., happy, sad, surprise, disgust.

Automation vs. robots

• Automation –Machinery designed to carry out a specific task– Bottling machine– Dishwasher– Paint sprayer

• Robots – machinery designed

to carry out a variety of tasks– Pick and place arms– Mobile robots– Computer Numerical Control

machines

(These are always better than robots, because they can be optimally designed

for a particular task).

• Actions– Simple joints

• prismatic—sliding joint, e.g., square cylinder in square tube

• revolute—hinge joint– Compound joints

• ball and socket = 3 revolute joints• round cylinder in tube = 1 prismatic, 1

revolute• Mobility

– Wheels– multipedal (multi-legged with a sequence of

actions)

Kinematics and dynamics (cont.)

Feedback control

• Rotation encoders

• Cameras

• Pressure sensors

• Temperature sensors

• Limit switches

• Optical sensors

• Sonar

Materials for Robotics

Bending of a Carbon nanotube

J.-P. Salvetat Adv. Mat. 11, 161-65 (1999).J.-P. Salvetat Phys. Rev. Lett. 82, 944-47 (1999).

Young’s Mod. = 810GPa.Shear Mod = 1GPa.

100 times smaller than a human hair (50-100um)

CNT’s are 100x stronger than steel.

Already being used in bridges

Neal Bridge, Pittstown, ME, USA

Micromotors for robotics

Watch motors: mechanical motors presently are 1-5mm in size.CNT motors are 0.01mm in size.

To be used for muscle joints, grips, making robot hands. S

An inverted pendulum robot (Strictly for fun!)

Has real applications: e.g., Segway transporter