Robotic limbs can be designed to look and function like organic limbs or be designed to do specific tasks that no known living organism can do. This section will focus on hands.
The differences between Robotic and Human hands is reducing all the time as we develop more humanoid robots and robotic limbs for humans that require them. However some robot hands are not designed to be like human hands, such as the Canadarm2 arm on the International Space station.
Muscles are used to provide the strength for motion, these expand and contract causing motion for organic life, robots can immitate this using Motors which turn clockwise and anticlockwise and are especially useful for circular motion such as wheels and pullies. When more strength is required Hydraulic Cylinders, which also expand and contract causing motion, are used, these can be seen in construction vehicles.
Tendons connect the muscles to the skeleton or exoskeletons of organic creatures, and ligaments connect the bones together. Robots and machines can relicate this using Gears, axles, pullies and levers, where the motion of a motor can be transfered into different types of motion. As we develop new technologies plastic tendons and ligaments are replacing more traditional mechanics, this is to replicate more organic motion.
Bones provide the Physical Structure of organisms, in mammels this strength is internal. The strength needed for a structure depends on the job it needs to do and this is very important for robots that are designed to do specific roles. Robots are not made from bone, but have physical sructure which can be made from lots of different matterials to do different tasks.
Organic organisms are full of nerves to provide the ability for life to feel and provide safety information, from catching a ball to typing a letter, many tasks we do every day would be more difficult without our ability to feel what we are doing, you can test this by wearing thick gloves and trying to do every day jobs. Our ability to feel also protects us from holding objects that are too sharp, hot or cold. Sensors and wires do the job in a Robot, connecting touch, temperature and other sensors to the processing unit (Brain) of the robot. However where organic organists mostly only have the ability to feel pressure and temperature a robot can be made to sense many other things, for example radiation or magnetic fields.
Finally organic limbs require a Blood Supply, to provide the energy for muscles and keep muscles strong and nerve cells alive. While robots do not need fuel in the way we do, they do require energy and a power supply, wires are connect pumps, sensors and motors for energy and communitcations, if strength comes from hydrolics then Hydraulic fluid and piping are also required.
Canadarm2 has Force movement sensors, these “Touch” sensors combined with its automatic imaging system “Sight” allow it to automatically and safely catch any free flying payloads. Its payloads can include Astronauts.
The Human hand works the same way, where the human eyes and hand work together to catch an object, judging its size and how delicate it is. Have you ever tried catching an egg?
Further Materials, Resources & Information
Below you will find more resources and external websites related to this lesson.
- www.arborsci.com (Pdf File) – Have a go at catching eggs with this Key Stage 3 activity about forces and momentum
- teachengineering.org – Learn about stuctures and strength by building then with straws.
- abc.net.au – Try to crush an egg activity.
- littlebinsforlittlehands.com – Simple activity for building foundations with eggs
- carolina.com – Have a go at building a working hand, can you improve on the design and add other structures to your model?