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QUIZ PREP

QUIZ PREP. Have Quiz sheet ready. Title = QUIZ 8 Name (L, F, MI), Today’s date 10/9/12 , Lab day , time section number. Announcements. First professional memo due today in lecture. Submit when called for.

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QUIZ PREP

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  1. QUIZ PREP • Have Quiz sheet ready. Title = QUIZ 8 • Name (L, F, MI), • Today’s date 10/9/12, • Lab day , time • section number

  2. Announcements • First professional memo due today in lecture. Submit when called for. • The preliminary design report is due at the beginning of your Week 10 lab mtg. • The final design report is due at the beginning of Week 13 lab.

  3. Design Reports: Audience • Design reports: Target audience is a busy technical manager, not … • Dr. Roppel • Your GTA • Mom • Team members • General public

  4. Design Reports: Audience Characteristics of your target audience: • Very limited time to comprehend your results. Can’t / won’t dig through fluff. Make results jump off the page. • Technically savvy, but not familiar with your project details (you must suspend reality here to get it right – role playing).

  5. Scores on Canvas • Check your scores on Canvas • If they are not right or not posted after two weeks, check with your GTA. • If you still need help, email me or see me in person. • All memos graded at same time, even if you submitted early.

  6. Announcements • Format and grading rubric for the Design Reports are on the class website and syllabus.

  7. Announcements • Each TEAM bring the following to lab this week: • Motor control board • Transmitter/receiver pair (check batteries – voltage should be above 10.0 V). • Two motors • R1 and R2 that will give you 10 to 12 V.

  8. Resistors • Can use resistors in lab for this week’s experiment. • You need to obtain your own for your car. • Science supply store (best option) • Radio Shack • Online (shipping cost!)

  9. Pulse Position Modulation - PPM • “Regular” or “Differential” PPM • Used for simplicity • Inexpensive, lightweight RX • Fine for R/C; not great for general communications

  10. “Regular” PPM

  11. Differential PPM Six Channels, all zero (center stick) except Channel 3 (right stick). 1 2 6 5 4 3 time Easier to decode – just need to detect time between two pulses. Differential PPM is what our setup uses.

  12. Servos and Op-Amps • Servos are special motors that include control circuitry. Used for precise control of position or velocity • DC servos are used in R/C and robots. AC servos are common in industry. • Op-Amps are important analog circuits. Used for amplifying, filtering, isolation, and motor control.

  13. DC Servos Web link

  14. Servos Purchase servos locally at Hobbytown USA

  15. Servos Position vs. Pulse Width • Input is a PWM signal; motor responds by turning to a fixed position. Example:

  16. Servo Control Signal Example

  17. Other Servo Types • Continuous Rotation (control speed and direction) • Digital • AC

  18. Continuous Rotation Servos • Can be purchased or can modify traditional servos. • “Neutral” signal (e.g. 1.5 ms) yields no movement. • PW >1.5 ms yields CW rotation. PW < 1.5 ms yields CCW rotation. • Great for driving robots.

  19. Digital Servos • Use a microprocessor to analyze incoming signal and perform motor control. • Higher pulse rate (300 Hz vs. 50 Hz) yields faster response, less deadband, more holding power. • ‘After flying digital servos, analogue versions are like controlling custard’ • Tradeoff: use more power.

  20. AC Servo Motors • Typically used for factory automation

  21. Op-Amps • Operational Amplifier • Developed circa 1940 by Bell Labs for telephone amplification. • Used for artillery aiming in WWII. • Analog computers • Now: input “pretreatment” and output buffering for DSP.

  22. Example Op-Amp Circuit Inverting Amplifier

  23. Op-Amp Circuit Analysis VX Gain = A Very large 0

  24. QUIZ PREP • Have Quiz sheet ready. Title = QUIZ 8 • Name (L, F, MI), • Today’s date 10/9/12, • Lab day , time • section number

  25. Quiz 8: Page 1 of 2 Write the correct answers on your Quiz sheet. 1. For a technical report, the use of lists, bullets, and headers should be avoided. TRUE / FALSE 2. The appropriate reader for whom you should target your design reports is: Dr. Roppel / Busy Manager / Mom 3. Differential PPM encodes joystick position as: Absolute pulse position / Space between pulses / Pulse width

  26. Quiz 8: page 2 of 2 4. For standard servos, position is determined by: Absolute pulse position / Space between pulses / Pulse width 5. Operational amplifiers are used primarily to: Calculate trajectories / Perform signal processing 6. Op-amps have internal voltage gain that is: Very small / Very large

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