Before define the “industrial robot” term, it’s important to define what is a robot.
Definition of a robot
A robot could be defined in a numbers of way depending of the activity sector. For the public, the robot term will be immediately associated with an humanoid robot of this type :
In the industrial world, the robot term is related to different types. Here are some exemples :
Theoretical definition of a robot
An industrial robot is a mechatronics device (mechanical, electronics, computer) doing automatic tasks which are generally dangerous, painful, repetitive, impossible for humans or simple tasks that could be done better (with higher quality or faster) than what could make a human.
This definition isn’t very accurate but resume well what is a robot.
Definition of an industrial robot
In the industrial world and specially in the domain of industrial robot, my definition is :
A robot is a device with multiple axes fixed together (from 2 to x axes) and controlled by an “intelligence”. This “intelligence” is composed of control electronics, power electronics and data processing (a computer). Movements of the robot could be done axis by axis or in a coordinate way (multiple axis move is same time).
What will do a big difference between a robot and a simple assembly of axes is that with a robot, all axes will moves is a coordinate way. I’ll get back on this point in details below.
A robot is a set of 2 main components :
- an axes system : which could be, for example, a 6 axes robot arm or a cartesian robot (XYZ table)
- a controller
In industrial robotics and generally in an industrial robot, it’s electrical axis technology which is the most common.
Axes are electrical (paired with a electrical motor) for matters of flexibility, regulation quality in speed and position, accuracy, …
Electrical axis motors are controlled by drives. Drives are controlled by a computer.
Each axis position is send to the corresponding drive by an encoder. This encoder lets the controller know each axis position in real time.
The axes system could take the shape of a robot arm (also named anthropomorphic arm), a cartesian robot (XYZ table), a SCARA robot (4 axes), a parallel robot (also named delta or spider robot), …
The axes system is connected to a controller by power and axes cables.
A robot controller is build with 2 main subassemblies :
- the driving and command part. This part is composed of multiple drives (depending of the number of axes in the industrial robot). Each of these drives is connected to the axis motor.
- the control part which is composed by a computer and a coordination unit. The control part is in charge to interpret the industrial robot program and makes position computations for each axis to get synchronized movements.
The controller gets often many other functions, like :
- transforming the primary power (generally very flexible and adaptable on a lot of power networks). This allow to work with different voltages and frequencies depending on installation site.
- distributing different powers : drives power, computer power, I/O (digital and analog inputs and outputs) power, security unit power, …
- security unit : This unit manages emergency stop signals, doors signals, manual and automatic modes of the robot,…
- axes computer unit : This unit is sometimes include inside the main computer but most of the time, the unit is separate to get better cycle time (response time). Indeed, we can’t afford waiting times of a classical computer program which can results in uncoordinated movements.
- I/O modules : We can generally found integrated I/O modules inside robot controller or field communication buses which allow to connect I/O modules.
- UPS (Uninterruptible Power Supply) to provide a power backup via battery during micro power shutdown or during controller shutdown process.
- A teachpendant which allow the robotician to make the teaching of the industrial robot and testing the program.
I’m Thibaud Norberg, a passionned robotics engineer, born in Belgium in 1981. My wife, my son and I live in Maredsous (Belgium) which is well known for his Abbey, cheese and, last but not least, his beer.
I’ve been working in robotics since 2003 in 2 companies which are called “integrators” in our domain.