Diff: main.cpp
- Revision:
- 0:6fee21a0a314
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Sat Aug 20 17:53:11 2011 +0000
@@ -0,0 +1,107 @@
+#include "mbed.h"
+#include "QEI.h"
+
+// Initialize motor PWM signal period and pulsewidth
+PwmOut speed(p22);
+DigitalIn SetSpeed(p20);
+Timer t;
+QEI encoder (p29, p30, NC, 18); //http://mbed.org/users/aberk/libraries/QEI/le4bkf, //http://mbed.org/cookbook/QEI
+Serial pc(USBTX, USBRX); // tx, rx
+float avgrpm;
+int main() {
+
+// Initialize motor PWM signal period and pulsewidth (Experimented to find these numbers)
+ //speed.period_us(100000); //Set the PWM period, specified in micro-seconds (int), keeping the duty cycle the same.
+ //speed.pulsewidth_us(10000); //Set the PWM pulsewidth, specified in micro-seconds (int), keeping the period the same.
+
+// Start motor forward at 25% speed
+ int s; s = 25000;
+ //speed.pulsewidth_us(s);
+
+// Aquire set point from user
+ int DutyCycle;
+ while ( (DutyCycle < 25) || (DutyCycle > 100) ){ // Experimented to determine this range
+ pc.printf("Enter a desired duty cycle between 25%% and 90%% as an interger.\n\n");
+ pc.scanf("%i", &DutyCycle);
+ }
+
+ pc.printf("Duty cycle set to %i%%\n\n", DutyCycle);
+ s = (DutyCycle * 1000);
+ //speed.pulsewidth_us(s);
+ wait(1);
+
+// Motor RPM average initialization and index
+ float rpm[5] = {0.0, 0.0, 0.0, 0.0, 0.0};
+ int i; i = 0;
+
+// Start program loop
+ while(1) {
+
+// Index and reset Motor Average Counter
+ if(i > 4) {
+ pc.printf("******Motor RPM %i= %f\n AVGRPM = %f\n\n", i, rpm[i], avgrpm);
+ i = 0;
+ }
+
+// Revolutions per minute
+ t.start();
+ encoder.reset(); // requires 1_us to execute
+ wait_ms(100); // requires 9.062_ms to execute
+ int pulse10ms = encoder.getPulses(); // requires 3.152 ms to execute for small numbers of pulses (i.e. < 10,000
+ t.stop();
+ pc.printf("Pulses Count is %i in %f ms\n", pulse10ms, t.read()*1000); // requires 13.542 ms to excute (cp: number of pulses per clock timer ~100ms)
+ rpm[i] = (60*pulse10ms)/(2*18*t.read()); // cp: rev/minute = 60 sec/min / timeInsec * pulses / 2*18 in1Revolution
+ avgrpm = (rpm[0] + rpm[1] + rpm[2] + rpm[3] + rpm[4]) / 5 ;
+ pc.printf("Motor RPM %i= %f\n AVGRPM = %f\n\n", i, rpm[i], avgrpm);
+ ++i;
+ t.reset();
+ wait(1);
+
+/* Speed Control of Motor ****(CHANGE TO LINE COMMENT TO ADD SPEED CONTROL)******
+
+// Build DC Motor Table and enter values into variables on the next line
+ /// cp: might need to interpoloate rpm20 //
+ int rpm20 = , rpm100 = , rpm60 = , rpm70 = , dcY = , rpmLimit = 250;
+ int SetSpeed;
+ static int j = 1;
+
+ if(j > 0){
+ while ( (SetSpeed < rpm60) || (SetSpeed > rpm70) ){
+ pc.printf("Enter a desired RPM between %i and %i as an interger.\n", rpm60, rpm70);
+ pc.scanf("%i", &SetSpeed);
+ pc.printf("RPM Set Point= %i rpm \n\n", SetSpeed);
+ DutyCycle = (80 * SetSpeed / (rpm100 - rpm20)) - dcY; // y = m*x + b (linear motor curve
+ pc.printf("Approx Duty Cycle = %i us \n", DutyCycle);
+ s = (DutyCycle * 1000);
+ pc.printf("Inital Pulse Width = %i us \n\n", s);
+ wait(2);
+ }
+ }
+ j = 0;
+ if ( avgrpm < (SetSpeed - rpmLimit)) {
+ DutyCycle = (DutyCycle + 1);
+ s = (DutyCycle * 1000);
+ pc.printf("Increase Duty Cycle= %i%%\n", DutyCycle);
+ pc.printf("Pulse Width = %i us \n\n", s);
+ speed.pulsewidth_us(s);
+ }
+ else if ( avgrpm > (SetSpeed + rpmLimit)){
+ DutyCycle = (DutyCycle - 1);
+ s = (DutyCycle*1000);
+ pc.printf("Decrease Duty Cycle= %i%%\n", DutyCycle);
+ pc.printf("Pulse Width = %i us \n\n", s);
+ speed.pulsewidth_us(s);
+ }
+ else if ( (avgrpm > (SetSpeed - rpmLimit)) || (avgrpm < (SetSpeed + rpmLimit)) ) {
+ s = DutyCycle * 1000;
+ pc.printf("Stable Duty Cycle= %i%%\n", DutyCycle);
+ pc.printf("Pulse Width = %i us \n\n", s);
+ }
+ else
+
+ return 0;
+
+*/ //****(CHANGE TO LINE COMMENT TO ADD SPEED CONTROL)
+
+ }
+}
clifton pang