ME 224 Experimental Engineering: Professor Espinosa 2005 TEAM : Jamie Charles Carlo Niko Javier

ME 224 Experimental Engineering: Professor Espinosa 2005 Overview Goal Assembly Programming Gyroscope Calibration Feedback Control Conclusion

ME 224 Experimental Engineering: Professor Espinosa 2005 Goal Goal is to follow given path

ME 224 Experimental Engineering: Professor Espinosa 2005 Assembly Building and assembly –Robotic kit –Additional parts Handy board Metal Wheely Bar Bread board –Gyroscope, Operational amplifier, low pass filter: R, C Programming –Several choices in programming codes

ME 224 Experimental Engineering: Professor Espinosa 2005 Programming Choosing the Code –Labview Non RealTime External connections –Basic Stamp Avoid analog to digital converter External computations Programmed in Basic

ME 224 Experimental Engineering: Professor Espinosa 2005 Programming Interactive C –Advantages Analog input with 8 bit precision No external connections Easier to program LCD display –Disadvantages Causes noise in the gyroscope rate out –CODE

ME 224 Experimental Engineering: Professor Espinosa 2005 Self Test * Verified Chip Function * Applied the following connections * Behavior: - +/-0.66V rateout

ME 224 Experimental Engineering: Professor Espinosa 2005 ADXRS150 - Angular Rate Sensor Fc = -2m(ω x vr)

ME 224 Experimental Engineering: Professor Espinosa 2005 Gyroscope Calibration First Stage –Rotate Robot at different angular velocities for different periods of time –Use Labview to obtain Output Voltage –Analyze data with Excel, taking an average of the output voltage –Test Robot

ME 224 Experimental Engineering: Professor Espinosa 2005 Labview Code

ME 224 Experimental Engineering: Professor Espinosa 2005 Obtained Data

ME 224 Experimental Engineering: Professor Espinosa 2005 Calibration Results

ME 224 Experimental Engineering: Professor Espinosa 2005 Gyroscope Calibration Angles not followed correctly Second Stage Calibration –Reduce noise caused mainly by vibrations and handy-board by adding a low-pass filter –Supply 5V instead of 4.75 V to gyroscope –Re-Calibrate using different method

ME 224 Experimental Engineering: Professor Espinosa 2005 Re-Calibration Write simple program to rotate robot 1080 degrees Adjust the “gyro calibration factor” (degrees/second/volt) Iterate several times until angle of rotation is accurate enough Test Robot by following the path

ME 224 Experimental Engineering: Professor Espinosa 2005 FeedBack Control Two Sectors of control –Straight –Turns Limitations of servos –Do not change speeds easily –20 millisecond update limit –Jitter response to noise

ME 224 Experimental Engineering: Professor Espinosa 2005 Is t < desired runtime L Calibrate gyro center: C (volts) NoYes Stop Servo Pulse: A7=const A5=const V < C -.03V > C +.03V = C ±.03 t = t +.5 Gyro output: V (volts) Correct Left: Servo A7 pulse +1 Correct Right Servo A5 pulse + 1 No Correction Feedback Control Diagram for Strait Linear Motion User Input: L (seconds)

ME 224 Experimental Engineering: Professor Espinosa 2005 Feedback Control Diagram for Constant Rotation Turns User Input: D (degrees) Calibrate gyro center: C (volts) Is Deg < D NoYes Servo Pulse: A7=const A5=const Calibrated gyro conversion factor: S (ω/volt) Stop Gyro output: V (volts) Deg = Deg + ω *.01 ω = (C-V)*S t = t +.01

ME 224 Experimental Engineering: Professor Espinosa 2005 Special Features No extensions / attached harnesses LCD read out Adjustable trajectory length Accuracy

ME 224 Experimental Engineering: Professor Espinosa 2005 Conclusion We applied learned techniques in Labview Utilized ECE knowledge –OpAmp voltage output modification –Capacitive filtering –Voltage Divider Created effective control programs Integrated Gyro Sensor Had Fun