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Dependencies:   mbed

WheelControl/Wheel.h@8:5ed6685f6edd, 2019-03-31 (annotated)

Committer:
mazdo25
Date:
Sun Mar 31 20:31:30 2019 +0000
Revision:
8:5ed6685f6edd
Parent:
6:477382219bcf
Child:
9:cefa177c1353
version used in test demo 3

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mazdo25 5:f1613df66ceb 1 class Wheel
mazdo25 5:f1613df66ceb 2 {
mazdo25 5:f1613df66ceb 3 private:
mazdo25 5:f1613df66ceb 4
mazdo25 5:f1613df66ceb 5 float distance; //distance traversed by wheel
mazdo25 5:f1613df66ceb 6 float angularVelocity;
mazdo25 5:f1613df66ceb 7
mazdo25 5:f1613df66ceb 8 float const static gain = 0.9f; //closed loop gain, (amount to amplify the difference) you have to tune this value
mazdo25 5:f1613df66ceb 9 //but make sure its less than 1.5 otherwise you'll have a really sensitive motor
mazdo25 5:f1613df66ceb 10
mazdo25 5:f1613df66ceb 11 PwmOut Mtr; //connect this pin to the motor driveboard pwm
mazdo25 5:f1613df66ceb 12 DigitalOut direction; //connected to the direction pin of motor drive board
mazdo25 5:f1613df66ceb 13 DigitalOut polarity; //connected to the bipolar of motor drive board. 0 = unipolar 1 = bipolar
mazdo25 5:f1613df66ceb 14
mazdo25 5:f1613df66ceb 15 Ticker updater;
mazdo25 5:f1613df66ceb 16
mazdo25 5:f1613df66ceb 17 Encoder* enc;
mazdo25 5:f1613df66ceb 18
mazdo25 5:f1613df66ceb 19 PID controller;
mazdo25 5:f1613df66ceb 20
mazdo25 5:f1613df66ceb 21 public:
mazdo25 5:f1613df66ceb 22
mazdo25 8:5ed6685f6edd 23 float maxAngularVel;
mazdo25 8:5ed6685f6edd 24 float minAngularVel;
mazdo25 5:f1613df66ceb 25
mazdo25 5:f1613df66ceb 26 float static const wheelDiameter = 0.18; //used in calculation of Linear velocity i.e never
mazdo25 5:f1613df66ceb 27
mazdo25 8:5ed6685f6edd 28 Wheel (Encoder* E, PinName M, PinName D, PinName Mode) : Mtr(M), direction(D), polarity(Mode), controller(gain,3.0f,0.00005f,0.0005f)
mazdo25 5:f1613df66ceb 29 {
mazdo25 5:f1613df66ceb 30 maxAngularVel = 0.0f;
mazdo25 5:f1613df66ceb 31 enc = E;
mazdo25 5:f1613df66ceb 32 polarity = 0;
mazdo25 5:f1613df66ceb 33 direction = 0;
mazdo25 5:f1613df66ceb 34 distance = 0;
mazdo25 5:f1613df66ceb 35 Mtr.period_us(100); //frequency of 5KHz determine this constant value based on switching losses+frequency losses
mazdo25 5:f1613df66ceb 36 //higher freq -> more switching losses lower freq -> more "capacitive losses" need to find a balance
mazdo25 5:f1613df66ceb 37 Mtr.write(1); //start off on the turned off state
mazdo25 5:f1613df66ceb 38
mazdo25 5:f1613df66ceb 39 updater.detach();
mazdo25 5:f1613df66ceb 40
mazdo25 5:f1613df66ceb 41 float *maxAVptr = &maxAngularVel;
mazdo25 5:f1613df66ceb 42 float *minAVPtr = &minAngularVel;
mazdo25 5:f1613df66ceb 43 controller.assignLimitAddress(maxAVptr,minAVPtr);
mazdo25 5:f1613df66ceb 44 }
mazdo25 5:f1613df66ceb 45
mazdo25 5:f1613df66ceb 46 void calculateAngularVelocity() //returns a float value which is the angular velocity of the WHEEL
mazdo25 5:f1613df66ceb 47 {
mazdo25 5:f1613df66ceb 48 float eTR = enc->encoderTickRate();
mazdo25 5:f1613df66ceb 49 angularVelocity = (eTR/256.0f)*2.0f*(float)PI;
mazdo25 5:f1613df66ceb 50 }
mazdo25 5:f1613df66ceb 51
mazdo25 5:f1613df66ceb 52 void setFrequency(int freq) //if you want to adjust the frequency
mazdo25 5:f1613df66ceb 53 {
mazdo25 5:f1613df66ceb 54 Mtr.period(1/freq);
mazdo25 5:f1613df66ceb 55 }
mazdo25 5:f1613df66ceb 56
mazdo25 5:f1613df66ceb 57 float returnAngularVelocity() //as it says
mazdo25 5:f1613df66ceb 58 {
mazdo25 5:f1613df66ceb 59 return angularVelocity;
mazdo25 5:f1613df66ceb 60 }
mazdo25 5:f1613df66ceb 61
mazdo25 5:f1613df66ceb 62 //only called once during initialization to calculate max angular velocity
mazdo25 5:f1613df66ceb 63 //dir = direction, do opposite for each wheel just so your buggy doesn't move FORWARD but rather rotates
mazdo25 5:f1613df66ceb 64 void init(int dir)
mazdo25 5:f1613df66ceb 65 {
mazdo25 5:f1613df66ceb 66 enc->startTimer();
mazdo25 5:f1613df66ceb 67 Mtr.write(0); //max speed
mazdo25 5:f1613df66ceb 68 angularVelocity = 10.0f;
mazdo25 5:f1613df66ceb 69 if (dir == 0) {direction = 0;} else {direction = 1;}
mazdo25 5:f1613df66ceb 70 updater.attach(callback(this, &Wheel::init2),0.6f); //used as a wait preferably put this wait just long enough that the buggy will do a full 360 degree turn so that it hasn't moved
mazdo25 5:f1613df66ceb 71 }
mazdo25 5:f1613df66ceb 72
mazdo25 5:f1613df66ceb 73 void init2(void) //used as a temporarily wait command for the wheel to spin to max
mazdo25 5:f1613df66ceb 74 {
mazdo25 6:477382219bcf 75 enc->startTimer();
mazdo25 5:f1613df66ceb 76 calculateAngularVelocity();
mazdo25 5:f1613df66ceb 77 maxAngularVel = 60.0f;
mazdo25 5:f1613df66ceb 78 minAngularVel = -1.0f*maxAngularVel;
mazdo25 5:f1613df66ceb 79 controller.setSetPoint(0.0f);
mazdo25 5:f1613df66ceb 80 updater.attach(callback(this, &Wheel::wheelUpdates),0.0005f);
mazdo25 5:f1613df66ceb 81 }
mazdo25 5:f1613df66ceb 82
mazdo25 5:f1613df66ceb 83 void startController()
mazdo25 5:f1613df66ceb 84 {
mazdo25 5:f1613df66ceb 85 updater.attach(callback(this, &Wheel::wheelUpdates),0.01f);
mazdo25 5:f1613df66ceb 86 }
mazdo25 5:f1613df66ceb 87
mazdo25 5:f1613df66ceb 88 void stopController()
mazdo25 5:f1613df66ceb 89 {
mazdo25 5:f1613df66ceb 90 updater.detach();
mazdo25 5:f1613df66ceb 91 }
mazdo25 5:f1613df66ceb 92
mazdo25 5:f1613df66ceb 93 void wheelUpdates(void) //sampling rate the ticker is attached I.E the wheel speed is updated everytime this function is called
mazdo25 5:f1613df66ceb 94 {
mazdo25 5:f1613df66ceb 95 calculateAngularVelocity();
mazdo25 8:5ed6685f6edd 96 //distance += angularVelocity*(wheelDiameter/2)*0.0005f;
mazdo25 5:f1613df66ceb 97 float temp2 = controller.compute(angularVelocity); //another temporary value to store the computed angular velocity
mazdo25 5:f1613df66ceb 98 if (temp2 < 0) {direction = 0;} else {direction = 1;} //change direction according to the computed value
mazdo25 5:f1613df66ceb 99 Mtr.write((1.0f - abs(temp2))); //write the value as a pwm
mazdo25 8:5ed6685f6edd 100
mazdo25 5:f1613df66ceb 101 }
mazdo25 5:f1613df66ceb 102
mazdo25 5:f1613df66ceb 103 void adjustAngularVelocity(float W) // W = angular velocity you want, obviously putting a |w| value that is > max angular velocity will set dutcy cycle to max
mazdo25 5:f1613df66ceb 104 {
mazdo25 5:f1613df66ceb 105 controller.setSetPoint(W);
mazdo25 5:f1613df66ceb 106 };
mazdo25 5:f1613df66ceb 107
mazdo25 5:f1613df66ceb 108 float getDistance(void)
mazdo25 5:f1613df66ceb 109 {
mazdo25 5:f1613df66ceb 110 return distance; //distance traversed by wheel
mazdo25 5:f1613df66ceb 111 }
mazdo25 5:f1613df66ceb 112
mazdo25 8:5ed6685f6edd 113 void stop()
mazdo25 8:5ed6685f6edd 114 {
mazdo25 8:5ed6685f6edd 115 controller.setSetPoint(0);
mazdo25 8:5ed6685f6edd 116 }
mazdo25 8:5ed6685f6edd 117
mazdo25 5:f1613df66ceb 118 float returnMaxAngularVel(void)
mazdo25 5:f1613df66ceb 119 {
mazdo25 5:f1613df66ceb 120 return maxAngularVel;
mazdo25 5:f1613df66ceb 121 }
mazdo25 5:f1613df66ceb 122
mazdo25 5:f1613df66ceb 123 float* returnMaxAVptr()
mazdo25 5:f1613df66ceb 124 {
mazdo25 5:f1613df66ceb 125 float *tempPTR = &maxAngularVel;
mazdo25 5:f1613df66ceb 126 return tempPTR;
mazdo25 5:f1613df66ceb 127 }
mazdo25 5:f1613df66ceb 128
mazdo25 5:f1613df66ceb 129 float* returnMinAVptr()
mazdo25 5:f1613df66ceb 130 {
mazdo25 5:f1613df66ceb 131 float *tempPTR = &minAngularVel;
mazdo25 5:f1613df66ceb 132 return tempPTR;
mazdo25 5:f1613df66ceb 133 }
mazdo25 5:f1613df66ceb 134
mazdo25 5:f1613df66ceb 135 };