Make A Model of a Robotic Arm End Effector
The history of robots begins in 350 BC with Archyta of Tarentum. He built a mechanical bird that was propelled by steam. The ancient Greeks liked to build mechanized figures of animals and humans. These mechanized figures are called automata. People still make automata today.
In 1495 Leonardo DaVinci designed an armored knight called “Leonardo’s Robot.” A person could stand inside and operate the pulleys and gears to bend the arms and legs. Pictured in Figure 1 is a modern-day version built from drawings made by Leonardo DaVinci.
What is the difference between a machine and a robot?
There are five main parts robot: a controller, an actuator, a drive, an end-effector, and a sensor.
- The controller is the computer that runs the robot. You can think of it as the “brain.” The controller gets feedback from the sensors.
- The actuator is a motor that moves parts of the robot and helps it do all or part of its job by moving parts of the robot.
- The drive is the engine that puts the robot and the robot arm into place.
- The sensor gives the robot information about its surroundings. A light sensor can detect light and dark. Temperature sensors can detect changes in the temperature. Think of situations in which a robot with a temperature sensor would be helpful.
- An end effector is the attachment at the end of the robotic arm. The end-effector may be a rubber gripper, a drill, a welding tool, a paint sprayer. What else can be used at the end of a robotic arm? Think about a robotic arm that would help you make a sandwich? What end effectors would it need to complete the task?
Many of the robots in existence today are robotic arms and work in factories performing dangerous or repetitive jobs. Robotic arms are used in automobile factories to assemble and weld, paint automobile bodies and move the heavy chassis. One automobile factory can utilize between 800 and 900 robots! In these factories, humans operate and repair the robots while the robots do the dangerous jobs and heavy lifting.
One famous robotic arm is the Canadarm2 on the International Space. Its full name is the Space Station Remote Manipulator System. It is strong enough to move about 20 elephants at one time! One of the end effectors on the Canadarm2 is a snare type of mechanism.
Three wires form a triangle and as the end effector turns, the triangle tightens around whatever the arm is trying to grab. Let’s make a model of the SSRMS end-effector.
Check out how this snare-type mechanism works by watching this video from the Canadian Space Agency of the arm on the International Space Station:
Make a Snare Type End Effector
- 1 piece Card stock
- 3 thin Rubber bands
- 1 Empty cardboard roll
- Small, lightweight items such as a pencil, bottle cap, paper clip.
- Gather the materials listed above.
- Cut a piece of card stock 4" x 7".
- Wrap the card stock piece around the cardboard roll. It should overlap about 1 inch. The card stock roll should be able to move, but not be too loose. See the video below if you need clarification.
- Tape the card stock tube closed. Do NOT tape it to the cardboard tube.
- Make 1 cut in each rubber band.
- Make 3 marks on the card board tub, equidistant apart.
- Staple one rubber band on each mark, near the top of the cardboard tube. Slide the card stock tube over the card board tube. Hang the rubber bands over the top of the card stock tube so they hand on the outside.
- Tape the rubber bands to the card stock tube.
- Hold the card board tube with one hand and twist the white card stock tube with the other hand.
- As you twist the rubber bands will form a triangular snare!
- Try holding different objects in the snare end effector.
If you enjoyed this STEM activity, check out others:
Check out more about the International Space Station Canadaarm