09 - Selma Lekuona Schlegel - Control and Robotics by Selma Lekuona Schlegel

A robot

lekuonaselma — 2025-03-19 12:49:37 UTC

It is a machine that performs a task or a variety of tasks automatically (without the direct control of a person) following a program.

A program

lekuonaselma — 2025-03-19 12:50:44 UTC

It is a list of orders (commands). Robots perform their tasks by following that list.

The Control

lekuonaselma — 2025-03-19 12:53:18 UTC

It is the part of the robot which is dedicated to regulating and governing the actions of the robot according to real-life situations.

Actuator (arm)

lekuonaselma — 2025-03-19 13:06:14 UTC

Most robots are "robotic arms" which work in production lines. It has a "manipulator" and a system of articulations.

The manipulator acts on the product which passes along the production line.
The system of articulations moves the manipulator to the correct place.

Power system

lekuonaselma — 2025-03-19 13:21:01 UTC

It generates the power necessary to move the arm and the manipulator of a robot. There are three types:

Electric power systems are the most common way to power robots and there are 3 types: AC motor, DC motor and step-by-step motor.
- AC and DC motors require constant control. The sensor give information and the controller tell the motor move or not.
- Step-by-step don't require sensor for position control. They don't have a lot of force, and they aren't energy efficient.
Pneumatic power system use compressed air as energy. A compressor compresses the air int a tank and then, the compressed air moves a piston inside the clyinder wich moves an actuator.
Hydraulic power systems use the pressure in oil as energy. An oil pump adds pressure to the oil from a tank, the oil travels through a system of pipes and the oil moves the actuators and then returns to the tank.

Sensors

lekuonaselma — 2025-03-21 12:41:11 UTC

It detect position, temperature, acceleration, etc. and it pass the data to the processor as an electric signal.

Position sensors are linear or angular. We use them to measure the position of an object, its size or its shape. There are 3 types:
- Inductive sensors detect metallic objects without touching them. They are a small electromagnet.
- Limit switches are the simplest type. They are a switch with a lever and a spring.
- LDRs (light dependent resistances) are resistances made of a semiconductor material that varies its resistivity with variations of light. We use it as part of photo-electric cells in automatic doors.
Force sensors: Different kinds of force sensors detect different forces.
Temperature sensors are very common. It are also used as safety devices in machines which have a risk of overheating.

The controller

lekuonaselma — 2025-03-21 12:50:10 UTC

It is the microprocessor that receives the signals (data) from the sensors. Decides what the actuators must do and then tells the actuator and the articulations of the arm when to move or stop.

It also has a memory to store:

The software (the logic).
Data, such as parameters for the program or information about the product.

Depending on the coordinate

lekuonaselma — 2025-03-21 12:57:45 UTC

Cartesian coordinates: The robot moves in a linge along the X, Y and/or Z axis. It needs to know the distance to move.
Polar coordinates: The robot rotates around the X, Y and/or Z axis. It needs to know how many degrees to rotate.

Depending on the degrees of freedom

lekuonaselma — 2025-03-25 16:57:56 UTC

The degrees of freedom are the number of axis along which the robotic arm can move, or around which the arm of the robot can rotate.
The minium is one, and the maximum is 6.

Depending on the energy used

lekuonaselma — 2025-03-25 16:59:22 UTC

Hydraulic.
Pneumatic.
Electric.

Where they work

lekuonaselma — 2025-03-25 17:03:46 UTC

Most robots "work" on production lines, especially where the activity is respective, dangerous or tiring.

For what they are generally used

lekuonaselma — 2025-03-25 17:07:20 UTC

They are generraly used if they have one or more of the following advantages:

More economical than a person.
Faster than a person.
Can work 24 hours a day.
Produce better quality.
Can work in dangerous places.

When the robots began

lekuonaselma — 2025-03-26 07:47:28 UTC

It's hard to say exactly when robotics began. Some historians, date the beginning of robotics to the middle ages, when machines were first used without direct human control.

In the first half of the 20th century, robots that worked with relays were first used. These automatisms were simple but funcional.

Modern robotics

lekuonaselma — 2025-03-26 07:56:32 UTC

It started with the development of microchips in the second half of century. Thanks to the microchips:

Logic can be more complex.
Robots are programmable: a programmer can chance the logic or the parameters.
Microchips are cheaper and more durable.

Artificial Intelligence

lekuonaselma — 2025-03-26 07:58:42 UTC

It is the capacity of the microprocessor to "learn from experience". The microprocessor control all of the movements based on its experience. For example, in a office building, the microprocessor controlling a lift remembers when people call the lift and from what floor.

Nano robots

lekuonaselma — 2025-03-26 07:58:53 UTC

Nano means "one million times smaller than the unit" (1mm=1/1,000m). The name "nano robots" refers to their very small size. For example, it's very eficient in medicine, to operate, because you can travel along human veins and un-block a blocked vein (It's only a example).