Ben Katz / Hobbyking_Cheetah_general

auto-measurements

Dependencies:   FastPWM3 mbed-dev

Fork of Hobbyking_Cheetah_Compact by Ben Katz

Calibration/calibration.cpp@34:47a55f96fbc4, 2017-10-02 (annotated)

Committer:
benkatz
Date:
Mon Oct 02 00:55:39 2017 +0000
Revision:
34:47a55f96fbc4
Parent:
28:8c7e29f719c5 
Auto-measurement

Who changed what in which revision?

UserRevisionLine numberNew contents of line
benkatz 22:60276ba87ac6 1 /// Calibration procedures for determining position sensor offset,
benkatz 22:60276ba87ac6 2 /// phase ordering, and position sensor linearization
benkatz 22:60276ba87ac6 3 ///
benkatz 22:60276ba87ac6 4
benkatz 22:60276ba87ac6 5 #include "calibration.h"
benkatz 23:2adf23ee0305 6 #include "foc.h"
benkatz 23:2adf23ee0305 7 #include "PreferenceWriter.h"
benkatz 23:2adf23ee0305 8 #include "user_config.h"
benkatz 34:47a55f96fbc4 9 #include "math.h"
benkatz 34:47a55f96fbc4 10 #include "math_ops.h"
benkatz 34:47a55f96fbc4 11
benkatz 34:47a55f96fbc4 12 void measure_rl(int n, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){
benkatz 34:47a55f96fbc4 13
benkatz 34:47a55f96fbc4 14
benkatz 34:47a55f96fbc4 15 }
benkatz 22:60276ba87ac6 16
benkatz 23:2adf23ee0305 17 void order_phases(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){
benkatz 28:8c7e29f719c5 18
benkatz 22:60276ba87ac6 19 ///Checks phase order, to ensure that positive Q current produces
benkatz 22:60276ba87ac6 20 ///torque in the positive direction wrt the position sensor.
benkatz 22:60276ba87ac6 21 printf("\n\r Checking phase ordering\n\r");
benkatz 22:60276ba87ac6 22 float theta_ref = 0;
benkatz 22:60276ba87ac6 23 float theta_actual = 0;
benkatz 34:47a55f96fbc4 24 float v_d = 2.0; //Put all volts on the D-Axis
benkatz 22:60276ba87ac6 25 float v_q = 0.0;
benkatz 22:60276ba87ac6 26 float v_u, v_v, v_w = 0;
benkatz 22:60276ba87ac6 27 float dtc_u, dtc_v, dtc_w = .5;
benkatz 22:60276ba87ac6 28 int sample_counter = 0;
benkatz 22:60276ba87ac6 29
benkatz 22:60276ba87ac6 30 ///Set voltage angle to zero, wait for rotor position to settle
benkatz 25:f5741040c4bb 31 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages
benkatz 34:47a55f96fbc4 32 svm(V_BUS, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation
benkatz 34:47a55f96fbc4 33 TIM1->CCR3 = (PWM_ARR)*(0.5f); // Set duty cycles
benkatz 34:47a55f96fbc4 34 TIM1->CCR2 = (PWM_ARR)*(0.5f);
benkatz 34:47a55f96fbc4 35 TIM1->CCR1 = (PWM_ARR)*(0.5f);
benkatz 34:47a55f96fbc4 36 wait_us(100);
benkatz 22:60276ba87ac6 37 for(int i = 0; i<20000; i++){
benkatz 34:47a55f96fbc4 38 wait_us(50);
benkatz 34:47a55f96fbc4 39 TIM1->CCR3 = (PWM_ARR)*(1.0f-dtc_u); // Set duty cycles
benkatz 34:47a55f96fbc4 40 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_v);
benkatz 34:47a55f96fbc4 41 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 42 }
benkatz 34:47a55f96fbc4 43
benkatz 34:47a55f96fbc4 44
benkatz 22:60276ba87ac6 45 //ps->ZeroPosition();
benkatz 22:60276ba87ac6 46 ps->Sample();
benkatz 23:2adf23ee0305 47 wait_us(1000);
benkatz 26:2b865c00d7e9 48 //float theta_start = ps->GetMechPosition(); //get initial rotor position
benkatz 26:2b865c00d7e9 49 float theta_start;
benkatz 34:47a55f96fbc4 50
benkatz 22:60276ba87ac6 51 /// Rotate voltage angle
benkatz 34:47a55f96fbc4 52 while(theta_ref < 4.0f*PI){ //rotate for 2 electrical cycles
benkatz 25:f5741040c4bb 53 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages
benkatz 34:47a55f96fbc4 54 svm(V_BUS, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation
benkatz 22:60276ba87ac6 55 wait_us(100);
benkatz 34:47a55f96fbc4 56 TIM1->CCR3 = (PWM_ARR)*(1.0f-dtc_u); //Set duty cycles
benkatz 34:47a55f96fbc4 57 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_v);
benkatz 34:47a55f96fbc4 58 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 25:f5741040c4bb 59 ps->Sample(); //sample position sensor
benkatz 22:60276ba87ac6 60 theta_actual = ps->GetMechPosition();
benkatz 26:2b865c00d7e9 61 if(theta_ref==0){theta_start = theta_actual;}
benkatz 22:60276ba87ac6 62 if(sample_counter > 200){
benkatz 22:60276ba87ac6 63 sample_counter = 0 ;
benkatz 22:60276ba87ac6 64 printf("%.4f %.4f\n\r", theta_ref/(NPP), theta_actual);
benkatz 22:60276ba87ac6 65 }
benkatz 22:60276ba87ac6 66 sample_counter++;
benkatz 22:60276ba87ac6 67 theta_ref += 0.001f;
benkatz 22:60276ba87ac6 68 }
benkatz 22:60276ba87ac6 69 float theta_end = ps->GetMechPosition();
benkatz 22:60276ba87ac6 70 int direction = (theta_end - theta_start)>0;
benkatz 34:47a55f96fbc4 71 float ratio = abs(4.0f*PI/(theta_end-theta_start));
benkatz 34:47a55f96fbc4 72 int pole_pairs = (int) roundf(ratio);
benkatz 34:47a55f96fbc4 73
benkatz 22:60276ba87ac6 74 printf("Theta Start: %f Theta End: %f\n\r", theta_start, theta_end);
benkatz 22:60276ba87ac6 75 printf("Direction: %d\n\r", direction);
benkatz 23:2adf23ee0305 76 if(direction){printf("Phasing correct\n\r");}
benkatz 22:60276ba87ac6 77 else if(!direction){printf("Phasing incorrect. Swapping phases V and W\n\r");}
benkatz 23:2adf23ee0305 78 PHASE_ORDER = direction;
benkatz 22:60276ba87ac6 79 }
benkatz 22:60276ba87ac6 80
benkatz 22:60276ba87ac6 81
benkatz 23:2adf23ee0305 82 void calibrate(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){
benkatz 22:60276ba87ac6 83 /// Measures the electrical angle offset of the position sensor
benkatz 22:60276ba87ac6 84 /// and (in the future) corrects nonlinearity due to position sensor eccentricity
benkatz 22:60276ba87ac6 85 printf("Starting calibration procedure\n\r");
benkatz 22:60276ba87ac6 86
benkatz 25:f5741040c4bb 87 const int n = 128*NPP; // number of positions to be sampled per mechanical rotation. Multiple of NPP for filtering reasons (see later)
benkatz 25:f5741040c4bb 88 const int n2 = 50; // increments between saved samples (for smoothing motion)
benkatz 25:f5741040c4bb 89 float delta = 2*PI*NPP/(n*n2); // change in angle between samples
benkatz 25:f5741040c4bb 90 float error_f[n] = {0}; // error vector rotating forwards
benkatz 25:f5741040c4bb 91 float error_b[n] = {0}; // error vector rotating backwards
benkatz 28:8c7e29f719c5 92 const int n_lut = 128;
benkatz 28:8c7e29f719c5 93 int lut[n_lut]= {0}; // clear any old lookup table before starting.
benkatz 28:8c7e29f719c5 94 ps->WriteLUT(lut);
benkatz 22:60276ba87ac6 95 int raw_f[n] = {0};
benkatz 22:60276ba87ac6 96 int raw_b[n] = {0};
benkatz 22:60276ba87ac6 97 float theta_ref = 0;
benkatz 22:60276ba87ac6 98 float theta_actual = 0;
benkatz 34:47a55f96fbc4 99 float v_d = 2.0f; // Put volts on the D-Axis
benkatz 22:60276ba87ac6 100 float v_q = 0.0;
benkatz 22:60276ba87ac6 101 float v_u, v_v, v_w = 0;
benkatz 22:60276ba87ac6 102 float dtc_u, dtc_v, dtc_w = .5;
benkatz 22:60276ba87ac6 103
benkatz 22:60276ba87ac6 104
benkatz 22:60276ba87ac6 105 ///Set voltage angle to zero, wait for rotor position to settle
benkatz 25:f5741040c4bb 106 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 34:47a55f96fbc4 107 svm(V_BUS, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 22:60276ba87ac6 108 for(int i = 0; i<40000; i++){
benkatz 34:47a55f96fbc4 109 TIM1->CCR3 = (PWM_ARR)*(1.0f-dtc_u); // Set duty cycles
benkatz 24:58c2d7571207 110 if(PHASE_ORDER){
benkatz 34:47a55f96fbc4 111 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_v);
benkatz 34:47a55f96fbc4 112 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 113 }
benkatz 22:60276ba87ac6 114 else{
benkatz 34:47a55f96fbc4 115 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_v);
benkatz 34:47a55f96fbc4 116 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 117 }
benkatz 22:60276ba87ac6 118 wait_us(100);
benkatz 22:60276ba87ac6 119 }
benkatz 22:60276ba87ac6 120 ps->Sample();
benkatz 26:2b865c00d7e9 121 printf(" Current Angle : Rotor Angle : Raw Encoder \n\r\n\r");
benkatz 25:f5741040c4bb 122 for(int i = 0; i<n; i++){ // rotate forwards
benkatz 22:60276ba87ac6 123 for(int j = 0; j<n2; j++){
benkatz 22:60276ba87ac6 124 theta_ref += delta;
benkatz 25:f5741040c4bb 125 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 34:47a55f96fbc4 126 svm(V_BUS, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 34:47a55f96fbc4 127 TIM1->CCR3 = (PWM_ARR)*(1.0f-dtc_u);
benkatz 25:f5741040c4bb 128 if(PHASE_ORDER){ // Check phase ordering
benkatz 34:47a55f96fbc4 129 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_v); // Set duty cycles
benkatz 34:47a55f96fbc4 130 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 131 }
benkatz 22:60276ba87ac6 132 else{
benkatz 34:47a55f96fbc4 133 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_v);
benkatz 34:47a55f96fbc4 134 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 135 }
benkatz 22:60276ba87ac6 136 wait_us(100);
benkatz 22:60276ba87ac6 137 ps->Sample();
benkatz 22:60276ba87ac6 138 }
benkatz 22:60276ba87ac6 139 ps->Sample();
benkatz 22:60276ba87ac6 140 theta_actual = ps->GetMechPosition();
benkatz 22:60276ba87ac6 141 error_f[i] = theta_ref/NPP - theta_actual;
benkatz 22:60276ba87ac6 142 raw_f[i] = ps->GetRawPosition();
benkatz 22:60276ba87ac6 143 printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_f[i]);
benkatz 22:60276ba87ac6 144 //theta_ref += delta;
benkatz 22:60276ba87ac6 145 }
benkatz 26:2b865c00d7e9 146
benkatz 25:f5741040c4bb 147 for(int i = 0; i<n; i++){ // rotate backwards
benkatz 22:60276ba87ac6 148 for(int j = 0; j<n2; j++){
benkatz 22:60276ba87ac6 149 theta_ref -= delta;
benkatz 25:f5741040c4bb 150 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 34:47a55f96fbc4 151 svm(V_BUS, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 34:47a55f96fbc4 152 TIM1->CCR3 = (PWM_ARR)*(1.0f-dtc_u);
benkatz 24:58c2d7571207 153 if(PHASE_ORDER){
benkatz 34:47a55f96fbc4 154 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_v);
benkatz 34:47a55f96fbc4 155 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 156 }
benkatz 22:60276ba87ac6 157 else{
benkatz 34:47a55f96fbc4 158 TIM1->CCR1 = (PWM_ARR)*(1.0f-dtc_v);
benkatz 34:47a55f96fbc4 159 TIM1->CCR2 = (PWM_ARR)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 160 }
benkatz 22:60276ba87ac6 161 wait_us(100);
benkatz 22:60276ba87ac6 162 ps->Sample();
benkatz 22:60276ba87ac6 163 }
benkatz 25:f5741040c4bb 164 ps->Sample(); // sample position sensor
benkatz 25:f5741040c4bb 165 theta_actual = ps->GetMechPosition(); // get mechanical position
benkatz 22:60276ba87ac6 166 error_b[i] = theta_ref/NPP - theta_actual;
benkatz 22:60276ba87ac6 167 raw_b[i] = ps->GetRawPosition();
benkatz 22:60276ba87ac6 168 printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_b[i]);
benkatz 22:60276ba87ac6 169 //theta_ref -= delta;
benkatz 22:60276ba87ac6 170 }
benkatz 22:60276ba87ac6 171
benkatz 22:60276ba87ac6 172 float offset = 0;
benkatz 22:60276ba87ac6 173 for(int i = 0; i<n; i++){
benkatz 25:f5741040c4bb 174 offset += (error_f[i] + error_b[n-1-i])/(2.0f*n); // calclate average position sensor offset
benkatz 22:60276ba87ac6 175 }
benkatz 25:f5741040c4bb 176 offset = fmod(offset*NPP, 2*PI); // convert mechanical angle to electrical angle
benkatz 23:2adf23ee0305 177
benkatz 22:60276ba87ac6 178
benkatz 25:f5741040c4bb 179 ps->SetElecOffset(offset); // Set position sensor offset
benkatz 23:2adf23ee0305 180 __float_reg[0] = offset;
benkatz 23:2adf23ee0305 181 E_OFFSET = offset;
benkatz 22:60276ba87ac6 182
benkatz 22:60276ba87ac6 183 /// Perform filtering to linearize position sensor eccentricity
benkatz 22:60276ba87ac6 184 /// FIR n-sample average, where n = number of samples in one electrical cycle
benkatz 22:60276ba87ac6 185 /// This filter has zero gain at electrical frequency and all integer multiples
benkatz 25:f5741040c4bb 186 /// So cogging effects should be completely filtered out.
benkatz 22:60276ba87ac6 187
benkatz 22:60276ba87ac6 188 float error[n] = {0};
benkatz 23:2adf23ee0305 189 const int window = 128;
benkatz 22:60276ba87ac6 190 float error_filt[n] = {0};
benkatz 22:60276ba87ac6 191 float mean = 0;
benkatz 25:f5741040c4bb 192 for (int i = 0; i<n; i++){ //Average the forward and back directions
benkatz 22:60276ba87ac6 193 error[i] = 0.5f*(error_f[i] + error_b[n-i-1]);
benkatz 22:60276ba87ac6 194 }
benkatz 22:60276ba87ac6 195 for (int i = 0; i<n; i++){
benkatz 22:60276ba87ac6 196 for(int j = 0; j<window; j++){
benkatz 25:f5741040c4bb 197 int ind = -window/2 + j + i; // Indexes from -window/2 to + window/2
benkatz 22:60276ba87ac6 198 if(ind<0){
benkatz 25:f5741040c4bb 199 ind += n;} // Moving average wraps around
benkatz 22:60276ba87ac6 200 else if(ind > n-1) {
benkatz 22:60276ba87ac6 201 ind -= n;}
benkatz 22:60276ba87ac6 202 error_filt[i] += error[ind]/(float)window;
benkatz 22:60276ba87ac6 203 }
benkatz 34:47a55f96fbc4 204
benkatz 22:60276ba87ac6 205 //printf("%.4f %4f %.4f %.4f\n\r", error[i], error_filt[i], error_f[i], error_b[i]);
benkatz 22:60276ba87ac6 206 mean += error_filt[i]/n;
benkatz 22:60276ba87ac6 207 }
benkatz 25:f5741040c4bb 208 int raw_offset = (raw_f[0] + raw_b[n-1])/2; //Insensitive to errors in this direction, so 2 points is plenty
benkatz 28:8c7e29f719c5 209
benkatz 28:8c7e29f719c5 210
benkatz 23:2adf23ee0305 211 printf("\n\r Encoder non-linearity compensation table\n\r");
benkatz 34:47a55f96fbc4 212 printf(" Sample Number : Lookup Index : Lookup Value\n\r\n\r");
benkatz 25:f5741040c4bb 213 for (int i = 0; i<n_lut; i++){ // build lookup table
benkatz 22:60276ba87ac6 214 int ind = (raw_offset>>7) + i;
benkatz 22:60276ba87ac6 215 if(ind > (n_lut-1)){
benkatz 22:60276ba87ac6 216 ind -= n_lut;
benkatz 22:60276ba87ac6 217 }
benkatz 22:60276ba87ac6 218 lut[ind] = (int) ((error_filt[i*NPP] - mean)*(float)(ps->GetCPR())/(2.0f*PI));
benkatz 34:47a55f96fbc4 219 printf("%d %d %d\n\r", i, ind, lut[ind]);
benkatz 26:2b865c00d7e9 220 wait(.001);
benkatz 22:60276ba87ac6 221 }
benkatz 23:2adf23ee0305 222
benkatz 25:f5741040c4bb 223 ps->WriteLUT(lut); // write lookup table to position sensor object
benkatz 25:f5741040c4bb 224 memcpy(&ENCODER_LUT, lut, sizeof(lut)); // copy the lookup table to the flash array
benkatz 23:2adf23ee0305 225 printf("\n\rEncoder Electrical Offset (rad) %f\n\r", offset);
benkatz 22:60276ba87ac6 226
benkatz 23:2adf23ee0305 227 if (!prefs->ready()) prefs->open();
benkatz 25:f5741040c4bb 228 prefs->flush(); // write offset and lookup table to flash
benkatz 25:f5741040c4bb 229 prefs->close();
benkatz 23:2adf23ee0305 230
benkatz 23:2adf23ee0305 231
benkatz 22:60276ba87ac6 232 }