The development of sensors and transducers very quickly according to the progress of automation technology, increasingly complex an automated system is built, the more types of sensors are used. Robotics is as an example of a complex automation system, sensors are used here can be categorized into two types of sensors, namely:
a. Internal sensor, the sensor mounted on the robot body.
Internal sensor is required to observe the position, velocity, and acceleration of various mechanical connection to the robot, and is part of the servo mechanism.
b. External sensor, the sensor is mounted outside the robot body.
External sensor is required for two reasons, namely:
1) For security and
2) For a guide.
Referred to the security “includes a security robot, ie the protection of the robots of the damage itself, as well as security for equipment, components, and people in the environment where the robot is used. Here are two simple examples to illustrate the above case.
The first example: suppose a move keposisinya new robot and he met an obstacle, which may be another engine for example. If the robot does not have a sensor that can detect the obstacle, either before or after contact, the result will be damage.
A second example: sensors to the security problem is illustrated by the robot in taking an egg. If the robot mounted mechanical gripper (gripper), then the sensor must be able to measure how much force is appropriate to take the eggs. Power that is too large will cause the breakup of eggs, whereas if it is too small eggs will fall apart.
Now how does the sensor to the guide or guides ?. Katogori is very broad, but the following examples will give consideration.
The first example: the components are located above the conveyor belt arrives in front of the robot programmed to spray him. What would happen if a component is missing or in the wrong position ?. Robots would have to have sensors that can detect the presence or absence of components, because otherwise he would spray the place is empty. Although no damage, but it is not something that is expected to occur in a factory.
A second example: a sensor for guiding expected quite sophisticated in welding. To perform the operation well, the robot must move the stalk welding along a predetermined weld line, and also moves with constant speed and maintain a certain distance to the surface.
In accordance with the function of the sensor as a detection signal and the signal gives the following information to the next system, the role and function of the sensor will be continued by the transducer. Because of the link between sensors and transducers so closely the selection of appropriate and corresponding transducer is also noteworthy.
classification Sensor
In general, based on the functions and use of sensors can be grouped into 3 parts:
a. sensor thermal (heat)
b. mechanical sensor
c. optical sensors (light)
Thermal sensor is a sensor used to detect the symptoms of heat changes / temperature / temperature to a dimension object or a specific room dimensions.
Example; bimetal, thermistors, thermocouples, RTD, photo transistors, photo diodes, photo multiplier, photovoltaic, infrared pyrometer, hygrometer, etc.
Mechanical sensor is a sensor that detects changes in mechanical motion, such as displacement or shift or position, straight and circular motion, pressure, flow, level and so on.
Example; strain gage, linear variable deferential transformer (LVDT), proximity, potentiometers, load cell, Bourdon tube, etc.
Optical or light sensor is a sensor that detects changes in light from the light source, the light reflection or refraction of light that mengernai objects or space.
Example; photo cell, photo transistors, photo diodes, photo voltaic, photo multiplier, optical pyrometer, etc.