Real-World Feedback/Control Systems

 

   

1. Targeted Ads
Whenever we search for a product on a search engine or buy things online, some companies take (or 'sense') this information and keeps track of our personal records. The company's computing system processes this information using an algorithm and makes a decision about what ads it should display for the particular consumer and their interests. The actuation is the placement of the ads on websites.

This feedback/control system works well because it customizes ads for the individual consumer, which increases the probability of the person actually clicking the ad and generating a profit for the company. However, it might not work as well for shared computers with different users.


2. Motion-Sensing Light Switch
The motion sensor constantly emits carrier waves and senses the reflected waves. When a person or an object comes near the sensor, the wave motion changes and is sensed by the sensor. The sensor can detect human motion specifically by detecting the infrared waves that is emitted by the human body. When the sensor detects the motion (or a presence of a human), it sends the information to the light switch which acts as a control mechanism that turns on the light. 
This feedback/control system works well because it only turns on the light when necessary. However, the sensor is not 100% accurate (which means the person might have to wave their arms near the sensor) and it is a bang-bang control without any subtle brightness controlling ability (It would be cool to have a feedback/control system that controls brightness of the light according to human needs!) 

http://www.unitedelectricalservices.com.au/sensor-light-combo.jpg

3. Vending Machines
When you put money into the vending machine, the machine detects the bill using optical sensors that look for identifying patterns in the bills. There are also other sensors that can tell counterfeit bills apart from the real bills. For coins, the machine usually detects its weight, size and magnetism. The information about the money is then transferred to the machine's system and that determines whether the money is real or fake. After the decision has been made, the machine spits the money back out if it's fake and accepts it if it is real.
This system works well because the machine is able to detect money without a human being present and detect counterfeits more easily. However, if there is a failure in the control, it could take your money and not give it back.

http://www.bmigaming.com/Games/Pictures/vending-machines/hr40-glass-front-snack-vending-machine-perfect-break-systems.jpg

 

 

 

 

4. Automatic Braking in Cars
Radars emits a signal and detects it when it is reflected off of an object and comes back.  A camera scans the object to help identify what the object is. The information from the radar and camera is brought to the car's computer, which then does calculations to determine the speed and the identity of the object in front of the car and decide on an appropriate response. The car's brakes actuates the computer's decision by either applying or not applying the braking force.
This system is very efficient because it can sometimes make decisions faster than the human nervous system, but it can be dangerous if the weather conditions are bad and there is very little friction between the wheel and the road.