• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Using a Rotary Potentiometer to Detect the Position of a Robotic Arm

Extracts from this document...

Introduction

Using a Rotary Potentiometer to Detect the Position of a Robotic Arm Plan: A rotary variable resistor would be set up as shown mechanically and electronically: Various different fixed resistors would be tried, with several readings taken for each. I suggest 9 readings should be taken, every twenty degrees starting at 20 for each resistor. That way, a full range of angles can be tried along the whole movement of the arm. Once the results have been obtained, then graphs can be plotted to calibrate the sensor, and from these graphs the most suitable resistor can be chosen for the sensor involved. Initial experiments show that all readings will be in the range of 0 to 5 volts. Results: Voltage across sensor (V) Resistor Used in Potential Divider (ohms) Degrees 100 220 470 1000 2200 4700 10000 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20 0.35 0.17 0.08 0.04 0.02 0.01 0.00 40 3.14 2.32 1.48 0.86 0.44 0.21 0.11 60 3.98 3.45 2.68 1.84 1.07 0.57 0.29 80 4.23 3.82 3.17 2.36 1.50 0.84 0.44 100 4.42 4.10 3.60 2.87 1.96 1.17 0.64 120 4.46 4.22 3.78 3.13 2.24 1.39 0.79 140 4.51 4.29 3.99 3.31 2.45 1.59 0.92 160 ...read more.

Middle

For example, the 100-ohm resistor has 12 readings less than 0.5 volts apart. This results in a low SD, even though the spread is less even). I have also divided the standard deviation by the range to allow for comparison between resistors of different ranges, and quantitative comparison. A larger graph that better depicts these readings is in the appendix. Again, the higher the SD/Range ratio the better for a generalist arm. However, I believe that range should also be maximized, and as such I believe the 2.2k? is the most effective in this role (see below). Linear variation is most desirable for this use in a non-specialist arm. This is beneficial, in a typical arm, because a large and even difference in voltage is present wherever the arm in its arc. A more specialized arm, for example in a car factory, might need great accuracy in a certain position, such as near the car, and less accuracy in others, like storage position, and well above the car. This arm would require a large spread of potential difference over certain angles, and smaller spread of potential difference over others. ...read more.

Conclusion

Its accuracy and range would be extremely good, however. Response time of the system was around 1 second. It was this poor due to the voltmeter used. The sensor itself had a very low response time. If linked into a different voltmeter, or logic circuitry, the response time would no longer be a problem, as the voltmeter that causes the delay has been removed entirely. In addition, there was no drift of the readings, as long as the arm was bound well enough to the sensor, and the extreme repeatability (near zero random variation) of the sensor means it would be very reliable as the position indicator for a robotic arm. I will end on the limitations to this project. It cannot consider the effects of time and age on the sensor, its reliability under adverse conditions such as varying temperature, vibration, shock, and water resistance. It did not compare the advantages of other rotary potentiometers over this one, either. Appendix: 1. 3.14-0.35 = 2.79 2.79*100 = 279 (as the voltmeter used was accurate to 0.01 volts) 279/20 = 13.95 1/13.95 � one fourteenth 2. 180*13.95 = 2511 ?/2511 = 0.001251132 0.001251132 * 1000 * 1 � one millimetre at 1 metre ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Systems and Control section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Systems and Control essays

  1. Bicycle Alarm Project

    one would be a waste of PCB space as well as expensive. It was therefore required to make one using logic gates. As the S and R inputs will not be selected together (this would give both Q and Q high on a simple flip-flop which is an invalid state)

  2. Getting On Line Without a Computer or Internet Access at Home

    Haledon Free PL; Northfield (Otto Bruyns PL); Northvale PL; Norwood PL; Nutley Free PL O Oakland PL; Oaklyn PL; Ocean City Free PL; Ocean County Library; Old Bridge PL; Old Tappan Free PL; Oradell Free PL; Orange PL P Palisades Park Free

  1. Design and Technology Project Design an Advertisement

    The acrylic is very easily cleaned, just requiring a quick wipe. Not exceed �10 I am aware budgeting was important to this project which is why I made sure to stick to my original amount of less than ten pounds.

  2. Build a sensor that detects air flow using an incandescent lamp to detect the ...

    As the Airflow gets stronger, the LED gets brighter and thus the voltage increases across the LED. The sensor worked well as demonstrated in the graph and the results.

  1. 'A small business wishes to sell a range of electronic games to help alleviate ...

    If an additional resistor is added between pin6 and GND then the unit is more immune to noise but less sensitive. Pin10 is a test pin and should not be connected to anything. PIN CONNECTIONS 1 Input's Ground 2 Capacitor Pin Amplifier I 3 Supply Voltage 4 Input Amplifier III

  2. The aim of my project is to produce a working 'People Counter', which will ...

    Note the output would not be crisp and sometimes distorted and possibly not very sensitive. Solution 2: This is the same as the first solution but replacing the LDR with a phototransistor. This circuit could give a more sensitive and sharper pulse from its input circuit output.

  1. An electronics firm wishes to introduce a range burglar alarms. This coursework contains the ...

    I can also make a 4 Input OR gate using a 4072 chip. This contains 2-4 Input OR gates in the 1 chip. It should be easier to use than any of the options above. Development combining the 4 Inputs To try and model the 4 inputs I will use crocodile clips.

  2. Design and build an electrical toy for children aged 5 years and over.

    fails to sell well and is sold to James Brunot who changed the name to Scrabble. The sales averaged just 8,000 but from 1953 to 1955 it suddenly takes off and sales reach 4.5 million sets. 1949 - Leeds-based Waddington's produced a mystery board game.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work