Motors are used in robots to drive the movement of the
joints. This can be done by powering a geared unit or driving a pump to move
air or fluids that will create a differential pressure. The main type of motor
that is used in robotics is an AC Servo motor. These motors are used due to the
fact that they can run at a high torque and have a resistance to external
forces so they cannot be moved.
There are two main ways in which brakes are used in
robots. The two methods are electrical braking and mechanical braking. Common
methods of electrical breaking include plugging, AC dynamic braking, DC
injection braking, Capacitive Braking and Regenerative Braking. The common
methods of mechanical braking is brake shoes and brake discs/callipers.
Each sensor that is used in robotics all have different
characteristics dependant on the circumstances and the task that is at hand.
The main purpose of a sensor is to give the robot awareness of its surroundings
and the presence of things such as physical objects, light, magnetic fields and
sound. They can also be used on the robot arm itself to judge motion forces and
are not only used in the robot work-cell.
There are many different types and sizes of teach pendant
but all of them are designed to instruct the robot from a hand held device.
They are generally used for step-by-step control and have the advantage to give
the operator a chance to perfect a task using real-time control. A dead mans
handle is fitted on all pendants that will disable the robot instantly if the
button is released and acts as an emergency stop button. The pendants can also
be switched between auto and teach mode.
End – Effector
The end effectors are the tools that will complete the
desired task that the robot has been assigned. The robot itself is programmed
to ensure that the end effectors are in their desired position and state in
free space. There are too many different end effectors to describe but some
examples may be some sort of claw that will pick and object up or a spray paint
gun that will move as told by its programme to cover a surface in paint. The
effector must have the ability to be placed into free space by the robot arm in
A) Identify 3 of the most common methods of robotic programming;
giving a description of each.
There are 3 common methods that can be used for robotic
programming. The main 3 are ‘Offline’, ‘Online’ and ‘Video’. Each one has
different advantages and disadvantages when it comes to programming.
Offline programming is achieved via a remote PC in which
some sort of programming software will be used. A popular software used for
programming is ‘Kuka Sim’. This allows you to import different types of robot
templates and environments that the robot may be in. Within the software you
can write various programmes to control your robot. It also allows you to
simulate the programme so you can see how the robot will move in real life. The
programme has the ability to identify any foreign objects that will obstruct
Offline programming allows you to write long and complex
programmes with minimal margin for error. The simulation function means that
you don’t have to test the robot physically in a potentially dangerous
environment where a wrong move or function could potentially cause damage to
equipment within the area.