SENSORS

Definition
a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena. The output is generally a signal that is converted to human-readable display at the sensor location or transmitted electronically over a network for reading or further processing.

CHARACTERISTICS

In robotics, sensors are used for both
internal feedback control and external
interaction with the outside environment

There are huge array of sensors available for measuring
almost every phenomenon. We will limit our discussion to
sensors used in conjunction with robotics, automation and
manufacturing industry.

Size and Weight
Depending on application of the sensor, the size may be of primary importance for example joint replacement sensors have to be adopted into the design of joints and move with the robot body element. The weight of sensor is also very important. A heavy sensors adds to the inertia of the arm and reduces its overall payload.

Type of Output
The output of the sensor may be digital or analog.
Depending on the application this may be used directly
or to be converted. The output of potentiometer is analog whereas that of an encoder is digital.

Interfacing
Sensors must be interfaced with other devices such as microprocessors and controllers. The interfacing between the sensor and the device can become an important issue if they do not match or if other add on components and circuits become necessary.

Resolution
Resolution is the minimum step size within the range of measurement of the sensor. In wire wound potentiometer it will be equal to the resistance of one turn of the wire. In digital device it is equal to (Full range/(2n))

Sensitivity and Linearity
Sensitivity is the ratio of change in output in response to a change in input and linearity represents the relationship between input variations and output variations. Highly sensitive sensors will show large fluctuations of output as a result of fluctuation in input.

Response Time
Response time is the time that a sensor’s output requires to reach a percentage of total change. It is usually expressed in percentage of total change such as 95%.

Reliability and Accuracy
Reliability is the ratio of how many times a system
operates properly divided by how many times it is used.
While accuracy is defined how close the output of the
sensor is to the expected value

TYPE OF
SENSORS

2. Position Sensors
Used to measure displacements,
both angular and linear as well
as movements

Types

Potentiometer
Converts position information into
a variable voltage through a resistor.
As the sliding contact slides on the resistor
due to change in position the proportion of
the resistance varies

Linear Velocity Differential Transducer (LVDT)
It is actually a transformer whose core moves with the distance measured and that outputs a variable analog voltage as a result of his displacement

1. Velocity Sensors
Their application is
very much related
to the type of the
position sensor.

Types

Tachometers
It is a generator that converts
mechanical energy into electrical energy.
Its output is analog voltage proportional to
input angular speed.

Encoders
A simple device that can output a
digital signal from each portion of
movement

5. Force and
Pressure Sensors

Types

Piezoelectric Transducers
Piezoelectric material compresses if exposed to
a voltage and produces voltage if compressed.
This principle is used to measure force or pressure.

Strain Gauge
The output of a strain gauge is a variable resistance,
proportional to a strain, which itself is a function of
applied force.

6. Proximity Sensors
To determine that an object is close
to another object before contact is made

Types

Magnetic Type
These sensors are activated when they are close to a magnet. Many devices have a magnetic proximity sensor that sends a signal when the door is open to stop the rotating of moving parts

Optical Proximity Sensors
Consists of a light source called emitter and a receiver, which senses the presence or the absence of light. The receiver is usually a phototransistor and the emitter is usually a LED.
The combination of two creates a light sensor and used in many applications.

Others

  • Ultrasonic, inductive, capacitive and
    eddy current proximity sensors

3. Visible Light and Infrared Sensors
React to the intensity of light projected onto them by
changing their electrical resistance. If intensity of light is zero,
the resistance is at maximum. As the light intensity increases
the resistance decreases and consequently current increases.
These sensors are very useful and can be used in making
optical encoders.

4. Torque Sensors
Torque can be measured by pair of strategically placed forced sensors. Suppose the two sensors are placed on shaft, opposite to each other, on opposite sides. If a torque is applied to the shaft, it generates two opposite forces on the shaft body, causing strains in opposite direction. The two sensors an measure the forces that can be converted into the couple.

Future Trends and Factors
Affecting Sensors and Automation
in Pharmaceutical Industries


  1. Empowered patients who become equal partners with their caregivers hack the whole healthcare system. These 'E-patients' will want to get into clinical trials. Some even acquire biotech companies to run their own trials.

  1. Health gamification, which makes it easier to motivate everyone to live more healthily. The incentives pharma companies are currently using to motive patients and medical professionals to use a certain product are obsolete. They need to turn to gamification to reach people where they are online, which can help improve both adherence and pharma's image.
  1. Augmented reality and virtual reality with devices such as Google Glass or Oculus Rift give us a new view of the world through digital information. If you have ever had a chance to use a virtual reality device, you can compare the attractiveness of information on a website with seeing how a drug works in 3D and realise the potential that virtual reality holds for pharma
  1. Genomics and truly personalised medicine to enable us to receive therapy individually customised to our own genetic background. I own a huge text file containing my DNA data. I can take it to my doctor and hope to receive personalised drugs instead of the blockbusters that are manufactured for millions of people even though we are all genetically and metabolically different.
  1. Body sensors, inside and out, that measure health parameters in a comfortable and cheap way to provide crucial data. The success of clinical trials largely depends on how medical professionals collect data about their patients. Imagine this being solved and made constant and automatic by increasing use of health sensors.
  1. 'Do it yourself' biotechnology that generates a new generation of scientists who see no limitations in research. The biggest drug ideas have come from large institutions, but this era might be over as citizen scientists like Jack Andraka, who developed a really disruptive pancreatic cancer test, can change the whole game in a speciality
  1. The 3D printing revolution that can manufacture medical prostheses, equipment, and pharmaceuticals. A Scottish group has been working on printing out drugs in 3D with a printer. Imagine getting a blueprint of a customised drug in a customised dosage related to your genomic background and that a local pharmacy could print it out for you, all without the participation of big pharma.
  1. The end of human experimentation through detailed simulation of human physiology. We live in a barbaric era when new drugs are tested on actual people. What if thousands of drug targets could be tested on billions of simulations modelling the physiology of the human body in seconds with supercomputers?
  1. Medical decision making with artificial intelligence, using the power of supercomputers in everyday medicine. Cognitive computers, such as IBM Watson, have been used in many ways to analyse big data, not only in genomic research but also in biotechnology. This will change the way new drugs are found.
  1. Nanorobots in our blood that can make early diagnoses by measuring any health parameters. If the technology of transporting drugs to the actual cellular targets in nanocages becomes viable, the pharma industry will have to start producing different end products to make sure they are compatible with nanotechnology.