Winnie Liu / Hobbyking_Cheetah_modify1105

hobbyking_cheetah source code modified 2020/12/15

Dependencies:   mbed-dev-f303 FastPWM3

FOC/foc.cpp@55:71a6e5fe5805, 2020-12-15 (annotated)

Committer:
WinnieLiu
Date:
Tue Dec 15 07:28:27 2020 +0000
Revision:
55:71a6e5fe5805
Parent:
53:e85efce8c1eb 
2020/12/15

Who changed what in which revision?

UserRevisionLine numberNew contents of line
WinnieLiu 55:71a6e5fe5805 1 /* -----
WinnieLiu 55:71a6e5fe5805 2 移除速度控制，把位置控制改成PID
WinnieLiu 55:71a6e5fe5805 3
WinnieLiu 55:71a6e5fe5805 4 log file:
WinnieLiu 55:71a6e5fe5805 5 11/05: 把現在的控制架構改成PID(torque_control)
WinnieLiu 55:71a6e5fe5805 6 ----- */
WinnieLiu 55:71a6e5fe5805 7
benkatz 37:c0f352d6e8e3 8
benkatz 22:60276ba87ac6 9 #include "foc.h"
WinnieLiu 55:71a6e5fe5805 10
WinnieLiu 55:71a6e5fe5805 11 //#define POS_MAX 6.283185f //359.9999 deg
benkatz 26:2b865c00d7e9 12 using namespace FastMath;
benkatz 22:60276ba87ac6 13
benkatz 22:60276ba87ac6 14
benkatz 22:60276ba87ac6 15 void abc( float theta, float d, float q, float *a, float *b, float *c){
benkatz 25:f5741040c4bb 16 /// Inverse DQ0 Transform ///
benkatz 22:60276ba87ac6 17 ///Phase current amplitude = lengh of dq vector///
benkatz 22:60276ba87ac6 18 ///i.e. iq = 1, id = 0, peak phase current of 1///
benkatz 37:c0f352d6e8e3 19 float cf = FastCos(theta);
benkatz 37:c0f352d6e8e3 20 float sf = FastSin(theta);
benkatz 37:c0f352d6e8e3 21
benkatz 37:c0f352d6e8e3 22 *a = cf*d - sf*q; // Faster Inverse DQ0 transform
benkatz 37:c0f352d6e8e3 23 *b = (0.86602540378f*sf-.5f*cf)*d - (-0.86602540378f*cf-.5f*sf)*q;
benkatz 37:c0f352d6e8e3 24 *c = (-0.86602540378f*sf-.5f*cf)*d - (0.86602540378f*cf-.5f*sf)*q;
benkatz 22:60276ba87ac6 25 }
benkatz 22:60276ba87ac6 26
benkatz 26:2b865c00d7e9 27
benkatz 22:60276ba87ac6 28 void dq0(float theta, float a, float b, float c, float *d, float *q){
benkatz 25:f5741040c4bb 29 /// DQ0 Transform ///
benkatz 22:60276ba87ac6 30 ///Phase current amplitude = lengh of dq vector///
benkatz 22:60276ba87ac6 31 ///i.e. iq = 1, id = 0, peak phase current of 1///
benkatz 22:60276ba87ac6 32
benkatz 37:c0f352d6e8e3 33 float cf = FastCos(theta);
benkatz 37:c0f352d6e8e3 34 float sf = FastSin(theta);
benkatz 26:2b865c00d7e9 35
benkatz 37:c0f352d6e8e3 36 *d = 0.6666667f*(cf*a + (0.86602540378f*sf-.5f*cf)*b + (-0.86602540378f*sf-.5f*cf)*c); ///Faster DQ0 Transform
benkatz 37:c0f352d6e8e3 37 *q = 0.6666667f*(-sf*a - (-0.86602540378f*cf-.5f*sf)*b - (0.86602540378f*cf-.5f*sf)*c);
benkatz 37:c0f352d6e8e3 38
benkatz 22:60276ba87ac6 39 }
benkatz 22:60276ba87ac6 40
benkatz 22:60276ba87ac6 41 void svm(float v_bus, float u, float v, float w, float *dtc_u, float *dtc_v, float *dtc_w){
benkatz 25:f5741040c4bb 42 /// Space Vector Modulation ///
benkatz 25:f5741040c4bb 43 /// u,v,w amplitude = v_bus for full modulation depth ///
benkatz 22:60276ba87ac6 44
benkatz 48:74a40481740c 45 float v_offset = (fminf3(u, v, w) + fmaxf3(u, v, w))*0.5f;
benkatz 47:e1196a851f76 46
benkatz 31:61eb6ae28215 47 *dtc_u = fminf(fmaxf(((u -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX);
benkatz 31:61eb6ae28215 48 *dtc_v = fminf(fmaxf(((v -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX);
benkatz 47:e1196a851f76 49 *dtc_w = fminf(fmaxf(((w -v_offset)/v_bus + .5f), DTC_MIN), DTC_MAX);
benkatz 47:e1196a851f76 50
benkatz 47:e1196a851f76 51 /*
benkatz 47:e1196a851f76 52 sinusoidal pwm
benkatz 47:e1196a851f76 53 *dtc_u = fminf(fmaxf((u/v_bus + .5f), DTC_MIN), DTC_MAX);
benkatz 47:e1196a851f76 54 *dtc_v = fminf(fmaxf((v/v_bus + .5f), DTC_MIN), DTC_MAX);
benkatz 47:e1196a851f76 55 *dtc_w = fminf(fmaxf((w/v_bus + .5f), DTC_MIN), DTC_MAX);
benkatz 47:e1196a851f76 56 */
benkatz 47:e1196a851f76 57
benkatz 22:60276ba87ac6 58
benkatz 22:60276ba87ac6 59 }
benkatz 22:60276ba87ac6 60
benkatz 48:74a40481740c 61 void linearize_dtc(float *dtc){
benkatz 48:74a40481740c 62 /// linearizes the output of the inverter, which is not linear for small duty cycles ///
benkatz 48:74a40481740c 63 float sgn = 1.0f-(2.0f*(dtc<0));
benkatz 48:74a40481740c 64 if(abs(*dtc) >= .01f){
benkatz 48:74a40481740c 65 *dtc = *dtc*.986f+.014f*sgn;
benkatz 48:74a40481740c 66 }
benkatz 48:74a40481740c 67 else{
benkatz 48:74a40481740c 68 *dtc = 2.5f*(*dtc);
benkatz 48:74a40481740c 69 }
benkatz 48:74a40481740c 70
benkatz 48:74a40481740c 71 }
benkatz 48:74a40481740c 72
benkatz 48:74a40481740c 73
benkatz 25:f5741040c4bb 74 void zero_current(int *offset_1, int *offset_2){ // Measure zero-offset of the current sensors
benkatz 22:60276ba87ac6 75 int adc1_offset = 0;
benkatz 22:60276ba87ac6 76 int adc2_offset = 0;
benkatz 22:60276ba87ac6 77 int n = 1024;
benkatz 25:f5741040c4bb 78 for (int i = 0; i<n; i++){ // Average n samples of the ADC
benkatz 27:501fee691e0e 79 TIM1->CCR3 = (PWM_ARR>>1)*(1.0f); // Write duty cycles
benkatz 27:501fee691e0e 80 TIM1->CCR2 = (PWM_ARR>>1)*(1.0f);
benkatz 27:501fee691e0e 81 TIM1->CCR1 = (PWM_ARR>>1)*(1.0f);
benkatz 26:2b865c00d7e9 82 ADC1->CR2 |= 0x40000000; // Begin sample and conversion
benkatz 22:60276ba87ac6 83 wait(.001);
benkatz 22:60276ba87ac6 84 adc2_offset += ADC2->DR;
benkatz 22:60276ba87ac6 85 adc1_offset += ADC1->DR;
benkatz 22:60276ba87ac6 86 }
benkatz 22:60276ba87ac6 87 *offset_1 = adc1_offset/n;
benkatz 22:60276ba87ac6 88 *offset_2 = adc2_offset/n;
benkatz 22:60276ba87ac6 89 }
benkatz 45:26801179208e 90
benkatz 45:26801179208e 91 void init_controller_params(ControllerStruct *controller){
benkatz 45:26801179208e 92 controller->ki_d = KI_D;
benkatz 45:26801179208e 93 controller->ki_q = KI_Q;
benkatz 45:26801179208e 94 controller->k_d = K_SCALE*I_BW;
benkatz 45:26801179208e 95 controller->k_q = K_SCALE*I_BW;
benkatz 45:26801179208e 96 controller->alpha = 1.0f - 1.0f/(1.0f - DT*I_BW*2.0f*PI);
benkatz 45:26801179208e 97
benkatz 45:26801179208e 98 }
benkatz 22:60276ba87ac6 99
benkatz 22:60276ba87ac6 100 void reset_foc(ControllerStruct *controller){
benkatz 28:8c7e29f719c5 101 TIM1->CCR3 = (PWM_ARR>>1)*(0.5f);
benkatz 28:8c7e29f719c5 102 TIM1->CCR1 = (PWM_ARR>>1)*(0.5f);
benkatz 28:8c7e29f719c5 103 TIM1->CCR2 = (PWM_ARR>>1)*(0.5f);
benkatz 28:8c7e29f719c5 104 controller->i_d_ref = 0;
benkatz 28:8c7e29f719c5 105 controller->i_q_ref = 0;
benkatz 28:8c7e29f719c5 106 controller->i_d = 0;
benkatz 28:8c7e29f719c5 107 controller->i_q = 0;
benkatz 37:c0f352d6e8e3 108 controller->i_q_filt = 0;
benkatz 22:60276ba87ac6 109 controller->q_int = 0;
benkatz 22:60276ba87ac6 110 controller->d_int = 0;
benkatz 28:8c7e29f719c5 111 controller->v_q = 0;
benkatz 28:8c7e29f719c5 112 controller->v_d = 0;
benkatz 47:e1196a851f76 113
benkatz 22:60276ba87ac6 114 }
benkatz 45:26801179208e 115
benkatz 48:74a40481740c 116 void reset_observer(ObserverStruct *observer){
benkatz 48:74a40481740c 117 observer->temperature = 25.0f;
benkatz 48:74a40481740c 118 observer->resistance = .1f;
benkatz 48:74a40481740c 119 }
benkatz 48:74a40481740c 120
benkatz 45:26801179208e 121 void limit_current_ref (ControllerStruct *controller){
benkatz 45:26801179208e 122 float i_q_max_limit = (0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
benkatz 45:26801179208e 123 float i_q_min_limit = (-0.5774f*controller->v_bus - controller->dtheta_elec*WB)/R_PHASE;
benkatz 45:26801179208e 124 controller->i_q_ref = fmaxf(fminf(i_q_max_limit, controller->i_q_ref), i_q_min_limit);
benkatz 45:26801179208e 125 }
benkatz 22:60276ba87ac6 126
benkatz 22:60276ba87ac6 127
benkatz 48:74a40481740c 128 void commutate(ControllerStruct *controller, ObserverStruct *observer, GPIOStruct *gpio, float theta){
benkatz 48:74a40481740c 129
benkatz 48:74a40481740c 130 /// Update observer estimates ///
benkatz 48:74a40481740c 131 // Resistance observer //
benkatz 48:74a40481740c 132 // Temperature Observer //
benkatz 48:74a40481740c 133 float t_rise = (float)observer->temperature - 25.0f;
benkatz 49:83d83040ea51 134 float q_th_in = (1.0f + .00393f*t_rise)*(controller->i_d*controller->i_d*R_PHASE*SQRT3 + controller->i_q*controller->i_q*R_PHASE*SQRT3);
benkatz 48:74a40481740c 135 float q_th_out = t_rise*R_TH;
benkatz 48:74a40481740c 136 observer->temperature += INV_M_TH*DT*(q_th_in-q_th_out);
benkatz 48:74a40481740c 137
benkatz 49:83d83040ea51 138 observer->resistance = (controller->v_q - SQRT3*controller->dtheta_elec*(WB))/controller->i_q;
benkatz 49:83d83040ea51 139 //observer->resistance = controller->v_q/controller->i_q;
benkatz 48:74a40481740c 140 if(isnan(observer->resistance)){observer->resistance = R_PHASE;}
benkatz 48:74a40481740c 141 observer->temperature2 = (double)(25.0f + ((observer->resistance*6.0606f)-1.0f)*275.5f);
benkatz 48:74a40481740c 142 double e = observer->temperature - observer->temperature2;
benkatz 48:74a40481740c 143 observer->temperature -= .001*e;
benkatz 48:74a40481740c 144 //printf("%.3f\n\r", e);
benkatz 48:74a40481740c 145
benkatz 47:e1196a851f76 146
benkatz 25:f5741040c4bb 147 /// Commutation Loop ///
benkatz 25:f5741040c4bb 148 controller->loop_count ++;
benkatz 25:f5741040c4bb 149 if(PHASE_ORDER){ // Check current sensor ordering
benkatz 25:f5741040c4bb 150 controller->i_b = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset); // Calculate phase currents from ADC readings
benkatz 22:60276ba87ac6 151 controller->i_c = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
benkatz 22:60276ba87ac6 152 }
benkatz 22:60276ba87ac6 153 else{
benkatz 25:f5741040c4bb 154 controller->i_b = I_SCALE*(float)(controller->adc1_raw - controller->adc1_offset);
benkatz 22:60276ba87ac6 155 controller->i_c = I_SCALE*(float)(controller->adc2_raw - controller->adc2_offset);
benkatz 22:60276ba87ac6 156 }
benkatz 26:2b865c00d7e9 157 controller->i_a = -controller->i_b - controller->i_c;
benkatz 22:60276ba87ac6 158
benkatz 26:2b865c00d7e9 159 float s = FastSin(theta);
benkatz 26:2b865c00d7e9 160 float c = FastCos(theta);
benkatz 44:8040fa2fcb0d 161 dq0(controller->theta_elec, controller->i_a, controller->i_b, controller->i_c, &controller->i_d, &controller->i_q); //dq0 transform on currents
benkatz 44:8040fa2fcb0d 162 //controller->i_d = 0.6666667f*(c*controller->i_a + (0.86602540378f*s-.5f*c)*controller->i_b + (-0.86602540378f*s-.5f*c)*controller->i_c); ///Faster DQ0 Transform
benkatz 44:8040fa2fcb0d 163 //controller->i_q = 0.6666667f*(-s*controller->i_a - (-0.86602540378f*c-.5f*s)*controller->i_b - (0.86602540378f*c-.5f*s)*controller->i_c);
benkatz 37:c0f352d6e8e3 164
benkatz 37:c0f352d6e8e3 165 controller->i_q_filt = 0.95f*controller->i_q_filt + 0.05f*controller->i_q;
benkatz 47:e1196a851f76 166 controller->i_d_filt = 0.95f*controller->i_d_filt + 0.05f*controller->i_d;
benkatz 37:c0f352d6e8e3 167
benkatz 45:26801179208e 168
benkatz 49:83d83040ea51 169 // Filter the current references to the desired closed-loop bandwidth
benkatz 45:26801179208e 170 controller->i_d_ref_filt = (1.0f-controller->alpha)*controller->i_d_ref_filt + controller->alpha*controller->i_d_ref;
benkatz 45:26801179208e 171 controller->i_q_ref_filt = (1.0f-controller->alpha)*controller->i_q_ref_filt + controller->alpha*controller->i_q_ref;
benkatz 48:74a40481740c 172
benkatz 48:74a40481740c 173
benkatz 48:74a40481740c 174 /// Field Weakening ///
benkatz 48:74a40481740c 175
benkatz 48:74a40481740c 176 controller->fw_int += .001f*(0.5f*OVERMODULATION*controller->v_bus - controller->v_ref);
benkatz 51:6cd89bd6fcaa 177 controller->fw_int = fmaxf(fminf(controller->fw_int, 0.0f), -I_FW_MAX);
benkatz 48:74a40481740c 178 controller->i_d_ref = controller->fw_int;
benkatz 48:74a40481740c 179 //float i_cmd_mag_sq = controller->i_d_ref*controller->i_d_ref + controller->i_q_ref*controller->i_q_ref;
benkatz 48:74a40481740c 180 limit_norm(&controller->i_d_ref, &controller->i_q_ref, I_MAX);
benkatz 25:f5741040c4bb 181
benkatz 47:e1196a851f76 182
benkatz 47:e1196a851f76 183
benkatz 25:f5741040c4bb 184 /// PI Controller ///
benkatz 22:60276ba87ac6 185 float i_d_error = controller->i_d_ref - controller->i_d;
benkatz 45:26801179208e 186 float i_q_error = controller->i_q_ref - controller->i_q;// + cogging_current;
benkatz 37:c0f352d6e8e3 187
benkatz 45:26801179208e 188 // Calculate feed-forward voltages //
benkatz 48:74a40481740c 189 float v_d_ff = SQRT3*(1.0f*controller->i_d_ref*R_PHASE - controller->dtheta_elec*L_Q*controller->i_q); //feed-forward voltages
benkatz 48:74a40481740c 190 float v_q_ff = SQRT3*(1.0f*controller->i_q_ref*R_PHASE + controller->dtheta_elec*(L_D*controller->i_d + 1.0f*WB));
benkatz 37:c0f352d6e8e3 191
benkatz 45:26801179208e 192 // Integrate Error //
benkatz 47:e1196a851f76 193 controller->d_int += controller->k_d*controller->ki_d*i_d_error;
benkatz 47:e1196a851f76 194 controller->q_int += controller->k_q*controller->ki_q*i_q_error;
benkatz 47:e1196a851f76 195
benkatz 47:e1196a851f76 196 controller->d_int = fmaxf(fminf(controller->d_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus);
benkatz 47:e1196a851f76 197 controller->q_int = fmaxf(fminf(controller->q_int, OVERMODULATION*controller->v_bus), - OVERMODULATION*controller->v_bus);
benkatz 47:e1196a851f76 198
benkatz 47:e1196a851f76 199 //limit_norm(&controller->d_int, &controller->q_int, OVERMODULATION*controller->v_bus);
benkatz 47:e1196a851f76 200 controller->v_d = controller->k_d*i_d_error + controller->d_int ;//+ v_d_ff;
benkatz 47:e1196a851f76 201 controller->v_q = controller->k_q*i_q_error + controller->q_int ;//+ v_q_ff;
benkatz 47:e1196a851f76 202
benkatz 47:e1196a851f76 203 controller->v_ref = sqrt(controller->v_d*controller->v_d + controller->v_q*controller->v_q);
benkatz 22:60276ba87ac6 204
benkatz 44:8040fa2fcb0d 205 limit_norm(&controller->v_d, &controller->v_q, OVERMODULATION*controller->v_bus); // Normalize voltage vector to lie within curcle of radius v_bus
benkatz 53:e85efce8c1eb 206 //float dtc_d = controller->v_d/controller->v_bus;
benkatz 53:e85efce8c1eb 207 //float dtc_q = controller->v_q/controller->v_bus;
benkatz 53:e85efce8c1eb 208 //linearize_dtc(&dtc_d);
benkatz 53:e85efce8c1eb 209 //linearize_dtc(&dtc_q);
benkatz 53:e85efce8c1eb 210 //controller->v_d = dtc_d*controller->v_bus;
benkatz 53:e85efce8c1eb 211 //controller->v_q = dtc_q*controller->v_bus;
benkatz 47:e1196a851f76 212 abc(controller->theta_elec + 0.0f*DT*controller->dtheta_elec, controller->v_d, controller->v_q, &controller->v_u, &controller->v_v, &controller->v_w); //inverse dq0 transform on voltages
benkatz 22:60276ba87ac6 213 svm(controller->v_bus, controller->v_u, controller->v_v, controller->v_w, &controller->dtc_u, &controller->dtc_v, &controller->dtc_w); //space vector modulation
benkatz 22:60276ba87ac6 214
benkatz 25:f5741040c4bb 215 if(PHASE_ORDER){ // Check which phase order to use,
benkatz 31:61eb6ae28215 216 TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u); // Write duty cycles
benkatz 31:61eb6ae28215 217 TIM1->CCR2 = (PWM_ARR)*(1.0f-controller->dtc_v);
benkatz 31:61eb6ae28215 218 TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_w);
benkatz 22:60276ba87ac6 219 }
benkatz 22:60276ba87ac6 220 else{
benkatz 32:ccac5da77844 221 TIM1->CCR3 = (PWM_ARR)*(1.0f-controller->dtc_u);
benkatz 32:ccac5da77844 222 TIM1->CCR1 = (PWM_ARR)*(1.0f-controller->dtc_v);
benkatz 32:ccac5da77844 223 TIM1->CCR2 = (PWM_ARR)*(1.0f-controller->dtc_w);
benkatz 22:60276ba87ac6 224 }
benkatz 25:f5741040c4bb 225
benkatz 48:74a40481740c 226 controller->theta_elec = theta;
benkatz 22:60276ba87ac6 227
benkatz 22:60276ba87ac6 228 }
benkatz 26:2b865c00d7e9 229
benkatz 26:2b865c00d7e9 230
benkatz 26:2b865c00d7e9 231 void torque_control(ControllerStruct *controller){
WinnieLiu 55:71a6e5fe5805 232 /*----- convert theta_mech to 0~359.9999deg -----*/
WinnieLiu 55:71a6e5fe5805 233 static float pos, round;
WinnieLiu 55:71a6e5fe5805 234 pos = controller->theta_mech;
WinnieLiu 55:71a6e5fe5805 235 modf(pos/(2*PI),&round);
WinnieLiu 55:71a6e5fe5805 236 pos = pos - round*2*PI;
WinnieLiu 55:71a6e5fe5805 237 if(abs(pos) <= 0.001)
WinnieLiu 55:71a6e5fe5805 238 pos = abs(pos);
WinnieLiu 55:71a6e5fe5805 239 else if(pos < 0)
WinnieLiu 55:71a6e5fe5805 240 pos = pos + 2*PI;
WinnieLiu 55:71a6e5fe5805 241 /*-----------------------------------------------*/
WinnieLiu 55:71a6e5fe5805 242
WinnieLiu 55:71a6e5fe5805 243 /*----- position PID control -----*/
WinnieLiu 55:71a6e5fe5805 244 static float in_err = 0, err = 0; //integral of position error
WinnieLiu 55:71a6e5fe5805 245 if(controller->p_des < pos)
WinnieLiu 55:71a6e5fe5805 246 if((controller->p_des + 2*PI - pos) < (pos - controller->p_des))
WinnieLiu 55:71a6e5fe5805 247 err = 2*PI - pos + controller->p_des;
WinnieLiu 55:71a6e5fe5805 248 else
WinnieLiu 55:71a6e5fe5805 249 err = controller->p_des - pos;
WinnieLiu 55:71a6e5fe5805 250 else
WinnieLiu 55:71a6e5fe5805 251 if((pos + 2*PI - controller->p_des) < (controller->p_des - pos))
WinnieLiu 55:71a6e5fe5805 252 err = controller->p_des - 2*PI - pos;
WinnieLiu 55:71a6e5fe5805 253 else
WinnieLiu 55:71a6e5fe5805 254 err = controller->p_des - pos;
WinnieLiu 55:71a6e5fe5805 255
WinnieLiu 55:71a6e5fe5805 256 in_err = in_err + err;
WinnieLiu 55:71a6e5fe5805 257 /*
WinnieLiu 55:71a6e5fe5805 258 err = controller->p_des - pos;
WinnieLiu 55:71a6e5fe5805 259 in_err = in_err + err;
WinnieLiu 55:71a6e5fe5805 260 */
WinnieLiu 55:71a6e5fe5805 261 float torque_ref = controller->kp*(err) + controller->t_ff + controller->ki*(in_err) + controller->kd*(-controller->dtheta_mech);
WinnieLiu 55:71a6e5fe5805 262 /*--------------------------------*/
WinnieLiu 55:71a6e5fe5805 263
WinnieLiu 55:71a6e5fe5805 264 //float torque_ref = controller->kp*(controller->p_des - controller->theta_mech) + controller->t_ff + controller->kd*(controller->v_des - controller->dtheta_mech);
benkatz 26:2b865c00d7e9 265 //float torque_ref = -.1*(controller->p_des - controller->theta_mech);
benkatz 26:2b865c00d7e9 266 controller->i_q_ref = torque_ref/KT_OUT;
benkatz 37:c0f352d6e8e3 267 controller->i_d_ref = 0.0f;
benkatz 26:2b865c00d7e9 268 }
benkatz 47:e1196a851f76 269