Ben Katz / HKC_MiniCheetah

Mini Cheetah Actuator Branch Superseded by: https://github.com/bgkatz/motorcontrol

Dependencies:   mbed-dev-f303 FastPWM3

Superseded by: https://github.com/bgkatz/motorcontrol

Calibration/calibration.cpp@26:2b865c00d7e9, 2017-05-01 (annotated)

Committer:
benkatz
Date:
Mon May 01 15:22:58 2017 +0000
Revision:
26:2b865c00d7e9
Parent:
25:f5741040c4bb
Child:
27:501fee691e0e
- Added CAN Send/Receive; - Updated to most recent MBED (Broke SPI 16-bit read/write.  Hacked to work with 2 8-bit writes now); - Removed most sine/cos calculations; - Fixed sign error in autocalibration routine

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 22:60276ba87ac6 9
benkatz 23:2adf23ee0305 10 void order_phases(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){
benkatz 22:60276ba87ac6 11 ///Checks phase order, to ensure that positive Q current produces
benkatz 22:60276ba87ac6 12 ///torque in the positive direction wrt the position sensor.
benkatz 22:60276ba87ac6 13 printf("\n\r Checking phase ordering\n\r");
benkatz 22:60276ba87ac6 14 float theta_ref = 0;
benkatz 22:60276ba87ac6 15 float theta_actual = 0;
benkatz 25:f5741040c4bb 16 float v_d = .2; //Put all volts on the D-Axis
benkatz 22:60276ba87ac6 17 float v_q = 0.0;
benkatz 22:60276ba87ac6 18 float v_u, v_v, v_w = 0;
benkatz 22:60276ba87ac6 19 float dtc_u, dtc_v, dtc_w = .5;
benkatz 22:60276ba87ac6 20 int sample_counter = 0;
benkatz 22:60276ba87ac6 21
benkatz 22:60276ba87ac6 22 ///Set voltage angle to zero, wait for rotor position to settle
benkatz 25:f5741040c4bb 23 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 24 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation
benkatz 22:60276ba87ac6 25 for(int i = 0; i<20000; i++){
benkatz 25:f5741040c4bb 26 TIM1->CCR3 = 0x708*(1.0f-dtc_u); // Set duty cycles
benkatz 22:60276ba87ac6 27 TIM1->CCR2 = 0x708*(1.0f-dtc_v);
benkatz 22:60276ba87ac6 28 TIM1->CCR1 = 0x708*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 29 wait_us(100);
benkatz 22:60276ba87ac6 30 }
benkatz 22:60276ba87ac6 31 //ps->ZeroPosition();
benkatz 22:60276ba87ac6 32 ps->Sample();
benkatz 23:2adf23ee0305 33 wait_us(1000);
benkatz 26:2b865c00d7e9 34 //float theta_start = ps->GetMechPosition(); //get initial rotor position
benkatz 26:2b865c00d7e9 35 float theta_start;
benkatz 23:2adf23ee0305 36 controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset); //Calculate phase currents from ADC readings
benkatz 23:2adf23ee0305 37 controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
benkatz 23:2adf23ee0305 38 controller->i_a = -controller->i_b - controller->i_c;
benkatz 23:2adf23ee0305 39 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 40 float current = sqrt(pow(controller->i_d, 2) + pow(controller->i_q, 2));
benkatz 23:2adf23ee0305 41 printf("\n\rCurrent\n\r");
benkatz 23:2adf23ee0305 42 printf("%f %f %f\n\r\n\r", controller->i_d, controller->i_q, current);
benkatz 22:60276ba87ac6 43 /// Rotate voltage angle
benkatz 25:f5741040c4bb 44 while(theta_ref < 4*PI){ //rotate for 2 electrical cycles
benkatz 25:f5741040c4bb 45 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); //inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 46 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); //space vector modulation
benkatz 22:60276ba87ac6 47 wait_us(100);
benkatz 25:f5741040c4bb 48 TIM1->CCR3 = 0x708*(1.0f-dtc_u); //Set duty cycles
benkatz 22:60276ba87ac6 49 TIM1->CCR2 = 0x708*(1.0f-dtc_v);
benkatz 22:60276ba87ac6 50 TIM1->CCR1 = 0x708*(1.0f-dtc_w);
benkatz 25:f5741040c4bb 51 ps->Sample(); //sample position sensor
benkatz 22:60276ba87ac6 52 theta_actual = ps->GetMechPosition();
benkatz 26:2b865c00d7e9 53 if(theta_ref==0){theta_start = theta_actual;}
benkatz 22:60276ba87ac6 54 if(sample_counter > 200){
benkatz 22:60276ba87ac6 55 sample_counter = 0 ;
benkatz 22:60276ba87ac6 56 printf("%.4f %.4f\n\r", theta_ref/(NPP), theta_actual);
benkatz 22:60276ba87ac6 57 }
benkatz 22:60276ba87ac6 58 sample_counter++;
benkatz 22:60276ba87ac6 59 theta_ref += 0.001f;
benkatz 22:60276ba87ac6 60 }
benkatz 22:60276ba87ac6 61 float theta_end = ps->GetMechPosition();
benkatz 22:60276ba87ac6 62 int direction = (theta_end - theta_start)>0;
benkatz 22:60276ba87ac6 63 printf("Theta Start: %f Theta End: %f\n\r", theta_start, theta_end);
benkatz 22:60276ba87ac6 64 printf("Direction: %d\n\r", direction);
benkatz 23:2adf23ee0305 65 if(direction){printf("Phasing correct\n\r");}
benkatz 22:60276ba87ac6 66 else if(!direction){printf("Phasing incorrect. Swapping phases V and W\n\r");}
benkatz 23:2adf23ee0305 67 PHASE_ORDER = direction;
benkatz 22:60276ba87ac6 68 }
benkatz 22:60276ba87ac6 69
benkatz 22:60276ba87ac6 70
benkatz 23:2adf23ee0305 71 void calibrate(PositionSensor *ps, GPIOStruct *gpio, ControllerStruct *controller, PreferenceWriter *prefs){
benkatz 22:60276ba87ac6 72 /// Measures the electrical angle offset of the position sensor
benkatz 22:60276ba87ac6 73 /// and (in the future) corrects nonlinearity due to position sensor eccentricity
benkatz 22:60276ba87ac6 74 printf("Starting calibration procedure\n\r");
benkatz 22:60276ba87ac6 75
benkatz 25:f5741040c4bb 76 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 77 const int n2 = 50; // increments between saved samples (for smoothing motion)
benkatz 25:f5741040c4bb 78 float delta = 2*PI*NPP/(n*n2); // change in angle between samples
benkatz 25:f5741040c4bb 79 float error_f[n] = {0}; // error vector rotating forwards
benkatz 25:f5741040c4bb 80 float error_b[n] = {0}; // error vector rotating backwards
benkatz 22:60276ba87ac6 81 int raw_f[n] = {0};
benkatz 22:60276ba87ac6 82 int raw_b[n] = {0};
benkatz 22:60276ba87ac6 83 float theta_ref = 0;
benkatz 22:60276ba87ac6 84 float theta_actual = 0;
benkatz 25:f5741040c4bb 85 float v_d = .2; // Put volts on the D-Axis
benkatz 22:60276ba87ac6 86 float v_q = 0.0;
benkatz 22:60276ba87ac6 87 float v_u, v_v, v_w = 0;
benkatz 22:60276ba87ac6 88 float dtc_u, dtc_v, dtc_w = .5;
benkatz 22:60276ba87ac6 89
benkatz 22:60276ba87ac6 90
benkatz 22:60276ba87ac6 91 ///Set voltage angle to zero, wait for rotor position to settle
benkatz 25:f5741040c4bb 92 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 93 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 22:60276ba87ac6 94 for(int i = 0; i<40000; i++){
benkatz 25:f5741040c4bb 95 TIM1->CCR3 = 0x708*(1.0f-dtc_u); // Set duty cycles
benkatz 24:58c2d7571207 96 if(PHASE_ORDER){
benkatz 22:60276ba87ac6 97 TIM1->CCR2 = 0x708*(1.0f-dtc_v);
benkatz 22:60276ba87ac6 98 TIM1->CCR1 = 0x708*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 99 }
benkatz 22:60276ba87ac6 100 else{
benkatz 22:60276ba87ac6 101 TIM1->CCR1 = 0x708*(1.0f-dtc_v);
benkatz 22:60276ba87ac6 102 TIM1->CCR2 = 0x708*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 103 }
benkatz 22:60276ba87ac6 104 wait_us(100);
benkatz 22:60276ba87ac6 105 }
benkatz 22:60276ba87ac6 106 ps->Sample();
benkatz 23:2adf23ee0305 107 controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset); //Calculate phase currents from ADC readings
benkatz 23:2adf23ee0305 108 controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
benkatz 23:2adf23ee0305 109 controller->i_a = -controller->i_b - controller->i_c;
benkatz 23:2adf23ee0305 110 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 111 float current = sqrt(pow(controller->i_d, 2) + pow(controller->i_q, 2));
benkatz 26:2b865c00d7e9 112 printf(" Current Angle : Rotor Angle : Raw Encoder \n\r\n\r");
benkatz 25:f5741040c4bb 113 for(int i = 0; i<n; i++){ // rotate forwards
benkatz 22:60276ba87ac6 114 for(int j = 0; j<n2; j++){
benkatz 22:60276ba87ac6 115 theta_ref += delta;
benkatz 25:f5741040c4bb 116 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 117 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 22:60276ba87ac6 118 TIM1->CCR3 = 0x708*(1.0f-dtc_u);
benkatz 25:f5741040c4bb 119 if(PHASE_ORDER){ // Check phase ordering
benkatz 25:f5741040c4bb 120 TIM1->CCR2 = 0x708*(1.0f-dtc_v); // Set duty cycles
benkatz 22:60276ba87ac6 121 TIM1->CCR1 = 0x708*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 122 }
benkatz 22:60276ba87ac6 123 else{
benkatz 22:60276ba87ac6 124 TIM1->CCR1 = 0x708*(1.0f-dtc_v);
benkatz 22:60276ba87ac6 125 TIM1->CCR2 = 0x708*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 126 }
benkatz 22:60276ba87ac6 127 wait_us(100);
benkatz 22:60276ba87ac6 128 ps->Sample();
benkatz 22:60276ba87ac6 129 }
benkatz 22:60276ba87ac6 130 ps->Sample();
benkatz 22:60276ba87ac6 131 theta_actual = ps->GetMechPosition();
benkatz 22:60276ba87ac6 132 error_f[i] = theta_ref/NPP - theta_actual;
benkatz 22:60276ba87ac6 133 raw_f[i] = ps->GetRawPosition();
benkatz 22:60276ba87ac6 134 printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_f[i]);
benkatz 22:60276ba87ac6 135 //theta_ref += delta;
benkatz 22:60276ba87ac6 136 }
benkatz 26:2b865c00d7e9 137
benkatz 25:f5741040c4bb 138 for(int i = 0; i<n; i++){ // rotate backwards
benkatz 22:60276ba87ac6 139 for(int j = 0; j<n2; j++){
benkatz 22:60276ba87ac6 140 theta_ref -= delta;
benkatz 25:f5741040c4bb 141 abc(theta_ref, v_d, v_q, &v_u, &v_v, &v_w); // inverse dq0 transform on voltages
benkatz 25:f5741040c4bb 142 svm(1.0, v_u, v_v, v_w, &dtc_u, &dtc_v, &dtc_w); // space vector modulation
benkatz 22:60276ba87ac6 143 TIM1->CCR3 = 0x708*(1.0f-dtc_u);
benkatz 24:58c2d7571207 144 if(PHASE_ORDER){
benkatz 22:60276ba87ac6 145 TIM1->CCR2 = 0x708*(1.0f-dtc_v);
benkatz 22:60276ba87ac6 146 TIM1->CCR1 = 0x708*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 147 }
benkatz 22:60276ba87ac6 148 else{
benkatz 22:60276ba87ac6 149 TIM1->CCR1 = 0x708*(1.0f-dtc_v);
benkatz 22:60276ba87ac6 150 TIM1->CCR2 = 0x708*(1.0f-dtc_w);
benkatz 22:60276ba87ac6 151 }
benkatz 22:60276ba87ac6 152 wait_us(100);
benkatz 22:60276ba87ac6 153 ps->Sample();
benkatz 22:60276ba87ac6 154 }
benkatz 25:f5741040c4bb 155 ps->Sample(); // sample position sensor
benkatz 25:f5741040c4bb 156 theta_actual = ps->GetMechPosition(); // get mechanical position
benkatz 22:60276ba87ac6 157 error_b[i] = theta_ref/NPP - theta_actual;
benkatz 22:60276ba87ac6 158 raw_b[i] = ps->GetRawPosition();
benkatz 22:60276ba87ac6 159 printf("%.4f %.4f %d\n\r", theta_ref/(NPP), theta_actual, raw_b[i]);
benkatz 22:60276ba87ac6 160 //theta_ref -= delta;
benkatz 22:60276ba87ac6 161 }
benkatz 22:60276ba87ac6 162
benkatz 22:60276ba87ac6 163 float offset = 0;
benkatz 22:60276ba87ac6 164 for(int i = 0; i<n; i++){
benkatz 25:f5741040c4bb 165 offset += (error_f[i] + error_b[n-1-i])/(2.0f*n); // calclate average position sensor offset
benkatz 22:60276ba87ac6 166 }
benkatz 25:f5741040c4bb 167 offset = fmod(offset*NPP, 2*PI); // convert mechanical angle to electrical angle
benkatz 23:2adf23ee0305 168
benkatz 22:60276ba87ac6 169
benkatz 25:f5741040c4bb 170 ps->SetElecOffset(offset); // Set position sensor offset
benkatz 23:2adf23ee0305 171 __float_reg[0] = offset;
benkatz 23:2adf23ee0305 172 E_OFFSET = offset;
benkatz 22:60276ba87ac6 173
benkatz 22:60276ba87ac6 174 /// Perform filtering to linearize position sensor eccentricity
benkatz 22:60276ba87ac6 175 /// FIR n-sample average, where n = number of samples in one electrical cycle
benkatz 22:60276ba87ac6 176 /// This filter has zero gain at electrical frequency and all integer multiples
benkatz 25:f5741040c4bb 177 /// So cogging effects should be completely filtered out.
benkatz 22:60276ba87ac6 178
benkatz 22:60276ba87ac6 179 float error[n] = {0};
benkatz 23:2adf23ee0305 180 const int window = 128;
benkatz 22:60276ba87ac6 181 float error_filt[n] = {0};
benkatz 23:2adf23ee0305 182 float cogging_current[window] = {0};
benkatz 22:60276ba87ac6 183 float mean = 0;
benkatz 25:f5741040c4bb 184 for (int i = 0; i<n; i++){ //Average the forward and back directions
benkatz 22:60276ba87ac6 185 error[i] = 0.5f*(error_f[i] + error_b[n-i-1]);
benkatz 22:60276ba87ac6 186 }
benkatz 22:60276ba87ac6 187 for (int i = 0; i<n; i++){
benkatz 22:60276ba87ac6 188 for(int j = 0; j<window; j++){
benkatz 25:f5741040c4bb 189 int ind = -window/2 + j + i; // Indexes from -window/2 to + window/2
benkatz 22:60276ba87ac6 190 if(ind<0){
benkatz 25:f5741040c4bb 191 ind += n;} // Moving average wraps around
benkatz 22:60276ba87ac6 192 else if(ind > n-1) {
benkatz 22:60276ba87ac6 193 ind -= n;}
benkatz 22:60276ba87ac6 194 error_filt[i] += error[ind]/(float)window;
benkatz 22:60276ba87ac6 195 }
benkatz 23:2adf23ee0305 196 if(i<window){
benkatz 23:2adf23ee0305 197 cogging_current[i] = current*sinf((error[i] - error_filt[i])*NPP);
benkatz 23:2adf23ee0305 198 }
benkatz 22:60276ba87ac6 199 //printf("%.4f %4f %.4f %.4f\n\r", error[i], error_filt[i], error_f[i], error_b[i]);
benkatz 22:60276ba87ac6 200 mean += error_filt[i]/n;
benkatz 22:60276ba87ac6 201 }
benkatz 25:f5741040c4bb 202 int raw_offset = (raw_f[0] + raw_b[n-1])/2; //Insensitive to errors in this direction, so 2 points is plenty
benkatz 22:60276ba87ac6 203 const int n_lut = 128;
benkatz 22:60276ba87ac6 204 int lut[n_lut];
benkatz 23:2adf23ee0305 205 printf("\n\r Encoder non-linearity compensation table\n\r");
benkatz 23:2adf23ee0305 206 printf(" Sample Number : Lookup Index : Lookup Value : Cogging Current Lookup\n\r\n\r");
benkatz 25:f5741040c4bb 207 for (int i = 0; i<n_lut; i++){ // build lookup table
benkatz 22:60276ba87ac6 208 int ind = (raw_offset>>7) + i;
benkatz 22:60276ba87ac6 209 if(ind > (n_lut-1)){
benkatz 22:60276ba87ac6 210 ind -= n_lut;
benkatz 22:60276ba87ac6 211 }
benkatz 22:60276ba87ac6 212 lut[ind] = (int) ((error_filt[i*NPP] - mean)*(float)(ps->GetCPR())/(2.0f*PI));
benkatz 23:2adf23ee0305 213 printf("%d %d %d %f\n\r", i, ind, lut[ind], cogging_current[i]);
benkatz 26:2b865c00d7e9 214 wait(.001);
benkatz 22:60276ba87ac6 215 }
benkatz 23:2adf23ee0305 216
benkatz 25:f5741040c4bb 217 ps->WriteLUT(lut); // write lookup table to position sensor object
benkatz 23:2adf23ee0305 218 //memcpy(controller->cogging, cogging_current, sizeof(controller->cogging)); //compensation doesn't actually work yet....
benkatz 25:f5741040c4bb 219 memcpy(&ENCODER_LUT, lut, sizeof(lut)); // copy the lookup table to the flash array
benkatz 23:2adf23ee0305 220 printf("\n\rEncoder Electrical Offset (rad) %f\n\r", offset);
benkatz 22:60276ba87ac6 221
benkatz 23:2adf23ee0305 222 if (!prefs->ready()) prefs->open();
benkatz 25:f5741040c4bb 223 prefs->flush(); // write offset and lookup table to flash
benkatz 25:f5741040c4bb 224 prefs->close();
benkatz 23:2adf23ee0305 225
benkatz 23:2adf23ee0305 226
benkatz 22:60276ba87ac6 227 }