Wooden Jin / BLDC_V2

bldc driver firmware based on hobbyking cheetah compact

Dependencies:   BLDC_V2 mbed-dev-f303 FastPWM3

Dependents:   BLDC_V2

Calibration/calibration.cpp@47:f4ecf3e0576a, 2020-05-13 (annotated)

Committer:
Wooden
Date:
Wed May 13 09:53:27 2020 +0000
Revision:
47:f4ecf3e0576a
Parent:
45:aadebe074af6
Child:
48:a74e401a6d84
bldc firmware based on hobbyking cheetah compact

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 44:efcde0af8390 9 #include "motor_config.h"
benkatz 44:efcde0af8390 10 #include "current_controller_config.h"
benkatz 22:60276ba87ac6 11
Wooden 47:f4ecf3e0576a 12 extern Serial pc;
Wooden 47:f4ecf3e0576a 13
benkatz 23:2adf23ee0305 14 void order_phases(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){
benkatz 28:8c7e29f719c5 15
benkatz 22:60276ba87ac6 16 ///Checks phase order, to ensure that positive Q current produces
benkatz 22:60276ba87ac6 17 ///torque in the positive direction wrt the position sensor.
Wooden 47:f4ecf3e0576a 18 pc.printf("\n\r Checking phase ordering\n\r");
benkatz 22:60276ba87ac6 19 float theta_ref = 0;
benkatz 22:60276ba87ac6 20 float theta_actual = 0;
benkatz 44:efcde0af8390 21 float v_d = .15f; //Put all volts on the D-Axis
benkatz 44:efcde0af8390 22 float v_q = 0.0f;
benkatz 22:60276ba87ac6 23 float v_u, v_v, v_w = 0;
benkatz 44:efcde0af8390 24 float dtc_u, dtc_v, dtc_w = .5f;
benkatz 22:60276ba87ac6 25 int sample_counter = 0;
benkatz 22:60276ba87ac6 26
benkatz 22:60276ba87ac6 27 ///Set voltage angle to zero, wait for rotor position to settle
benkatz 25:f5741040c4bb 28 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 29 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation
benkatz 22:60276ba87ac6 30 for(int i = 0; i<20000; i++){
benkatz 27:501fee691e0e 31 TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); // Set duty cycles
benkatz 27:501fee691e0e 32 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v);
benkatz 27:501fee691e0e 33 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 34 wait_us(100);
benkatz 22:60276ba87ac6 35 }
benkatz 22:60276ba87ac6 36 //ps->ZeroPosition();
benkatz 45:aadebe074af6 37 ps->Sample(DT);
benkatz 23:2adf23ee0305 38 wait_us(1000);
benkatz 38:67e4e1453a4b 39 //float theta_start = ps->GetMechPositionFixed(); //get initial rotor position
benkatz 26:2b865c00d7e9 40 float theta_start;
benkatz 23:2adf23ee0305 41 controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset); //Calculate phase currents from ADC readings
benkatz 23:2adf23ee0305 42 controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
benkatz 23:2adf23ee0305 43 controller->i_a = -controller->i_b - controller->i_c;
benkatz 23:2adf23ee0305 44 dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q); //dq0 transform on currents
benkatz 23:2adf23ee0305 45 float current = sqrt(pow(controller->i_d, 2) + pow(controller->i_q, 2));
Wooden 47:f4ecf3e0576a 46 pc.printf("\n\rCurrent\n\r");
Wooden 47:f4ecf3e0576a 47 pc.printf("%f %f %f\n\r\n\r", controller->i_d, controller->i_q, current);
benkatz 22:60276ba87ac6 48 /// Rotate voltage angle
benkatz 25:f5741040c4bb 49 while(theta_ref < 4*PI){ //rotate for 2 electrical cycles
benkatz 25:f5741040c4bb 50 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 51 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation
benkatz 22:60276ba87ac6 52 wait_us(100);
benkatz 27:501fee691e0e 53 TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); //Set duty cycles
benkatz 27:501fee691e0e 54 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v);
benkatz 27:501fee691e0e 55 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 45:aadebe074af6 56 ps->Sample(DT); //sample position sensor
benkatz 38:67e4e1453a4b 57 theta_actual = ps->GetMechPositionFixed();
benkatz 26:2b865c00d7e9 58 if(theta_ref==0){theta_start = theta_actual;}
benkatz 22:60276ba87ac6 59 if(sample_counter > 200){
benkatz 22:60276ba87ac6 60 sample_counter = 0 ;
Wooden 47:f4ecf3e0576a 61 pc.printf("%.4f %.4f\n\r", theta_ref/(NPP), theta_actual);
benkatz 22:60276ba87ac6 62 }
benkatz 22:60276ba87ac6 63 sample_counter++;
benkatz 22:60276ba87ac6 64 theta_ref += 0.001f;
benkatz 22:60276ba87ac6 65 }
benkatz 38:67e4e1453a4b 66 float theta_end = ps->GetMechPositionFixed();
benkatz 22:60276ba87ac6 67 int direction = (theta_end - theta_start)>0;
Wooden 47:f4ecf3e0576a 68 pc.printf("Theta Start: %f Theta End: %f\n\r", theta_start, theta_end);
Wooden 47:f4ecf3e0576a 69 pc.printf("Direction: %d\n\r", direction);
Wooden 47:f4ecf3e0576a 70 if(direction){pc.printf("Phasing correct\n\r");}
Wooden 47:f4ecf3e0576a 71 else if(!direction){pc.printf("Phasing incorrect. Swapping phases V and W\n\r");}
benkatz 23:2adf23ee0305 72 PHASE_ORDER = direction;
benkatz 22:60276ba87ac6 73 }
benkatz 22:60276ba87ac6 74
benkatz 22:60276ba87ac6 75
benkatz 23:2adf23ee0305 76 void calibrate(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){
benkatz 22:60276ba87ac6 77 /// Measures the electrical angle offset of the position sensor
benkatz 22:60276ba87ac6 78 /// and (in the future) corrects nonlinearity due to position sensor eccentricity
Wooden 47:f4ecf3e0576a 79 pc.printf("Starting calibration procedure\n\r");
benkatz 22:60276ba87ac6 80
benkatz 25:f5741040c4bb 81 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 82 const int n2 = 50; // increments between saved samples (for smoothing motion)
benkatz 25:f5741040c4bb 83 float delta = 2*PI*NPP/(n*n2); // change in angle between samples
benkatz 25:f5741040c4bb 84 float error_f[n] = {0}; // error vector rotating forwards
benkatz 25:f5741040c4bb 85 float error_b[n] = {0}; // error vector rotating backwards
benkatz 28:8c7e29f719c5 86 const int n_lut = 128;
benkatz 28:8c7e29f719c5 87 int lut[n_lut]= {0}; // clear any old lookup table before starting.
benkatz 28:8c7e29f719c5 88 ps->WriteLUT(lut);
benkatz 22:60276ba87ac6 89 int raw_f[n] = {0};
benkatz 22:60276ba87ac6 90 int raw_b[n] = {0};
benkatz 22:60276ba87ac6 91 float theta_ref = 0;
benkatz 22:60276ba87ac6 92 float theta_actual = 0;
benkatz 44:efcde0af8390 93 float v_d = .15f; // Put volts on the D-Axis
benkatz 44:efcde0af8390 94 float v_q = 0.0f;
benkatz 22:60276ba87ac6 95 float v_u, v_v, v_w = 0;
benkatz 44:efcde0af8390 96 float dtc_u, dtc_v, dtc_w = .5f;
benkatz 22:60276ba87ac6 97
benkatz 22:60276ba87ac6 98
benkatz 22:60276ba87ac6 99 ///Set voltage angle to zero, wait for rotor position to settle
benkatz 25:f5741040c4bb 100 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 101 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 22:60276ba87ac6 102 for(int i = 0; i<40000; i++){
benkatz 27:501fee691e0e 103 TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u); // Set duty cycles
benkatz 24:58c2d7571207 104 if(PHASE_ORDER){
benkatz 27:501fee691e0e 105 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v);
benkatz 27:501fee691e0e 106 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 107 }
benkatz 22:60276ba87ac6 108 else{
benkatz 27:501fee691e0e 109 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_v);
benkatz 27:501fee691e0e 110 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 111 }
benkatz 22:60276ba87ac6 112 wait_us(100);
benkatz 22:60276ba87ac6 113 }
benkatz 45:aadebe074af6 114 ps->Sample(DT);
benkatz 23:2adf23ee0305 115 controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset); //Calculate phase currents from ADC readings
benkatz 23:2adf23ee0305 116 controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
benkatz 23:2adf23ee0305 117 controller->i_a = -controller->i_b - controller->i_c;
benkatz 23:2adf23ee0305 118 dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q); //dq0 transform on currents
benkatz 23:2adf23ee0305 119 float current = sqrt(pow(controller->i_d, 2) + pow(controller->i_q, 2));
Wooden 47:f4ecf3e0576a 120 pc.printf(" Current Angle : Rotor Angle : Raw Encoder \n\r\n\r");
benkatz 25:f5741040c4bb 121 for(int i = 0; i<n; i++){ // rotate forwards
benkatz 22:60276ba87ac6 122 for(int j = 0; j<n2; j++){
benkatz 22:60276ba87ac6 123 theta_ref += delta;
benkatz 25:f5741040c4bb 124 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 125 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 27:501fee691e0e 126 TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u);
benkatz 25:f5741040c4bb 127 if(PHASE_ORDER){ // Check phase ordering
benkatz 27:501fee691e0e 128 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v); // Set duty cycles
benkatz 27:501fee691e0e 129 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 130 }
benkatz 22:60276ba87ac6 131 else{
benkatz 27:501fee691e0e 132 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_v);
benkatz 27:501fee691e0e 133 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 134 }
benkatz 22:60276ba87ac6 135 wait_us(100);
benkatz 45:aadebe074af6 136 ps->Sample(DT);
benkatz 22:60276ba87ac6 137 }
benkatz 45:aadebe074af6 138 ps->Sample(DT);
benkatz 38:67e4e1453a4b 139 theta_actual = ps->GetMechPositionFixed();
benkatz 22:60276ba87ac6 140 error_f[i] = theta_ref/NPP - theta_actual;
benkatz 22:60276ba87ac6 141 raw_f[i] = ps->GetRawPosition();
Wooden 47:f4ecf3e0576a 142 pc.printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_f[i]);
benkatz 22:60276ba87ac6 143 //theta_ref += delta;
benkatz 22:60276ba87ac6 144 }
benkatz 26:2b865c00d7e9 145
benkatz 25:f5741040c4bb 146 for(int i = 0; i<n; i++){ // rotate backwards
benkatz 22:60276ba87ac6 147 for(int j = 0; j<n2; j++){
benkatz 22:60276ba87ac6 148 theta_ref -= delta;
benkatz 25:f5741040c4bb 149 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 150 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 27:501fee691e0e 151 TIM1->CCR3 = (PWM_ARR>>1)*(1.0f-dtc_u);
benkatz 24:58c2d7571207 152 if(PHASE_ORDER){
benkatz 27:501fee691e0e 153 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_v);
benkatz 27:501fee691e0e 154 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 155 }
benkatz 22:60276ba87ac6 156 else{
benkatz 27:501fee691e0e 157 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f-dtc_v);
benkatz 27:501fee691e0e 158 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 159 }
benkatz 22:60276ba87ac6 160 wait_us(100);
benkatz 45:aadebe074af6 161 ps->Sample(DT);
benkatz 22:60276ba87ac6 162 }
benkatz 45:aadebe074af6 163 ps->Sample(DT); // sample position sensor
benkatz 38:67e4e1453a4b 164 theta_actual = ps->GetMechPositionFixed(); // get mechanical position
benkatz 22:60276ba87ac6 165 error_b[i] = theta_ref/NPP - theta_actual;
benkatz 22:60276ba87ac6 166 raw_b[i] = ps->GetRawPosition();
Wooden 47:f4ecf3e0576a 167 pc.printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_b[i]);
benkatz 22:60276ba87ac6 168 //theta_ref -= delta;
benkatz 22:60276ba87ac6 169 }
benkatz 22:60276ba87ac6 170
benkatz 22:60276ba87ac6 171 float offset = 0;
benkatz 22:60276ba87ac6 172 for(int i = 0; i<n; i++){
benkatz 25:f5741040c4bb 173 offset += (error_f[i] + error_b[n-1-i])/(2.0f*n); // calclate average position sensor offset
benkatz 22:60276ba87ac6 174 }
benkatz 25:f5741040c4bb 175 offset = fmod(offset*NPP, 2*PI); // convert mechanical angle to electrical angle
benkatz 23:2adf23ee0305 176
benkatz 22:60276ba87ac6 177
benkatz 25:f5741040c4bb 178 ps->SetElecOffset(offset); // Set position sensor offset
benkatz 23:2adf23ee0305 179 __float_reg[0] = offset;
benkatz 23:2adf23ee0305 180 E_OFFSET = offset;
benkatz 22:60276ba87ac6 181
benkatz 22:60276ba87ac6 182 /// Perform filtering to linearize position sensor eccentricity
benkatz 22:60276ba87ac6 183 /// FIR n-sample average, where n = number of samples in one electrical cycle
benkatz 22:60276ba87ac6 184 /// This filter has zero gain at electrical frequency and all integer multiples
benkatz 25:f5741040c4bb 185 /// So cogging effects should be completely filtered out.
benkatz 22:60276ba87ac6 186
benkatz 22:60276ba87ac6 187 float error[n] = {0};
benkatz 23:2adf23ee0305 188 const int window = 128;
benkatz 22:60276ba87ac6 189 float error_filt[n] = {0};
benkatz 23:2adf23ee0305 190 float cogging_current[window] = {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 23:2adf23ee0305 204 if(i<window){
benkatz 23:2adf23ee0305 205 cogging_current[i] = current*sinf((error[i] - error_filt[i])*NPP);
benkatz 23:2adf23ee0305 206 }
benkatz 22:60276ba87ac6 207 //printf("%.4f %4f %.4f %.4f\n\r", error[i], error_filt[i], error_f[i], error_b[i]);
benkatz 22:60276ba87ac6 208 mean += error_filt[i]/n;
benkatz 22:60276ba87ac6 209 }
benkatz 25:f5741040c4bb 210 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 211
benkatz 28:8c7e29f719c5 212
Wooden 47:f4ecf3e0576a 213 pc.printf("\n\r Encoder non-linearity compensation table\n\r");
Wooden 47:f4ecf3e0576a 214 pc.printf(" Sample Number : Lookup Index : Lookup Value : Cogging Current Lookup\n\r\n\r");
benkatz 25:f5741040c4bb 215 for (int i = 0; i<n_lut; i++){ // build lookup table
benkatz 22:60276ba87ac6 216 int ind = (raw_offset>>7) + i;
benkatz 22:60276ba87ac6 217 if(ind > (n_lut-1)){
benkatz 22:60276ba87ac6 218 ind -= n_lut;
benkatz 22:60276ba87ac6 219 }
benkatz 22:60276ba87ac6 220 lut[ind] = (int) ((error_filt[i*NPP] - mean)*(float)(ps->GetCPR())/(2.0f*PI));
Wooden 47:f4ecf3e0576a 221 pc.printf("%d %d %d %f\n\r", i, ind, lut[ind], cogging_current[i]);
benkatz 26:2b865c00d7e9 222 wait(.001);
benkatz 22:60276ba87ac6 223 }
benkatz 23:2adf23ee0305 224
benkatz 25:f5741040c4bb 225 ps->WriteLUT(lut); // write lookup table to position sensor object
benkatz 23:2adf23ee0305 226 //memcpy(controller->cogging, cogging_current, sizeof(controller->cogging)); //compensation doesn't actually work yet....
benkatz 25:f5741040c4bb 227 memcpy(&ENCODER_LUT, lut, sizeof(lut)); // copy the lookup table to the flash array
Wooden 47:f4ecf3e0576a 228 pc.printf("\n\rEncoder Electrical Offset (rad) %f\n\r", offset);
benkatz 22:60276ba87ac6 229
benkatz 23:2adf23ee0305 230 if (!prefs->ready()) prefs->open();
benkatz 25:f5741040c4bb 231 prefs->flush(); // write offset and lookup table to flash
benkatz 25:f5741040c4bb 232 prefs->close();
benkatz 23:2adf23ee0305 233
benkatz 23:2adf23ee0305 234
benkatz 22:60276ba87ac6 235 }