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ODrive/MotorControl/low_level.c
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/* Includes ------------------------------------------------------------------*/
// Because of broken cmsis_os.h, we need to include arm_math first,
// otherwise chip specific defines are ommited
#include <stm32f4xx_hal.h> //Sets up the correct chip specifc defines required by arm_math
#define ARM_MATH_CM4
#include <arm_math.h>
#include <low_level.h>
#include <stdlib.h>
#include <math.h>
#include <cmsis_os.h>
#include <main.h>
#include <adc.h>
#include <tim.h>
#include <spi.h>
#include <utils.h>
/* Private defines -----------------------------------------------------------*/
#ifndef M_PI
#define M_PI 3.14159265358979323846f
#endif
/* Private macros ------------------------------------------------------------*/
/* Private typedef -----------------------------------------------------------*/
/* Global constant data ------------------------------------------------------*/
/* Global variables ----------------------------------------------------------*/
float vbus_voltage = 12.0f; //Arbitrary non-zero inital value to avoid division by zero if ADC reading is late
//@TODO: Migrate to C++, clearly we are actually doing object oriented code here...
Motor_t motors[] = {
{ //M0
.motor_thread = 0,
.thread_ready = false,
.motor_timer = &htim1,
.next_timings = {TIM_PERIOD_CLOCKS/2, TIM_PERIOD_CLOCKS/2, TIM_PERIOD_CLOCKS/2},
.control_deadline = TIM_PERIOD_CLOCKS,
.current_meas = {0.0f, 0.0f},
.DC_calib = {0.0f, 0.0f},
.gate_driver = {
.spiHandle = &hspi3,
//Note: this board has the EN_Gate pin shared!
.EngpioHandle = EN_GATE_GPIO_Port,
.EngpioNumber = EN_GATE_Pin,
.nCSgpioHandle = M0_nCS_GPIO_Port,
.nCSgpioNumber = M0_nCS_Pin,
.RxTimeOut = false,
.enableTimeOut = false
},
.shunt_conductance = 1.0f/0.0005f, //[S]
.current_control = {
.current_lim = 75.0f, //[A] //Note: consistent with 40v/v gain
.p_gain = 0.0f, // [V/A] should be auto set after resistance and inductance measurement
.i_gain = 0.0f, // [V/As] should be auto set after resistance and inductance measurement
.v_current_control_integral_d = 0.0f,
.v_current_control_integral_q = 0.0f
},
.rotor = {
.encoder_timer = &htim3,
.encoder_offset = 0,
.encoder_state = 0,
.phase = 0.0f, // [rad]
.pll_pos = 0.0f, // [rad]
.pll_vel = 0.0f, // [rad/s]
.pll_kp = 0.0f, // [rad/s / rad]
.pll_ki = 0.0f // [(rad/s^2) / rad]
}
},
{ //M1
.motor_thread = 0,
.thread_ready = false,
.motor_timer = &htim8,
.next_timings = {TIM_PERIOD_CLOCKS/2, TIM_PERIOD_CLOCKS/2, TIM_PERIOD_CLOCKS/2},
.control_deadline = (3*TIM_PERIOD_CLOCKS)/2,
.current_meas = {0.0f, 0.0f},
.DC_calib = {0.0f, 0.0f},
.gate_driver = {
.spiHandle = &hspi3,
//Note: this board has the EN_Gate pin shared!
.EngpioHandle = EN_GATE_GPIO_Port,
.EngpioNumber = EN_GATE_Pin,
.nCSgpioHandle = M1_nCS_GPIO_Port,
.nCSgpioNumber = M1_nCS_Pin,
.RxTimeOut = false,
.enableTimeOut = false
},
.shunt_conductance = 1.0f/0.0005f, //[S]
.current_control = {
.current_lim = 75.0f, //[A] //Note: consistent with 40v/v gain
.p_gain = 0.0f, // [V/A] should be auto set after resistance and inductance measurement
.i_gain = 0.0f, // [V/As] should be auto set after resistance and inductance measurement
.v_current_control_integral_d = 0.0f,
.v_current_control_integral_q = 0.0f
},
.rotor = {
.encoder_timer = &htim4,
.encoder_offset = 0,
.encoder_state = 0,
.phase = 0.0f,
.pll_pos = 0.0f, // [rad]
.pll_vel = 0.0f, // [rad/s]
.pll_kp = 0.0f, // [rad/s / rad]
.pll_ki = 0.0f // [(rad/s^2) / rad]
}
}
};
const int num_motors = sizeof(motors)/sizeof(motors[0]);
/* Private constant data -----------------------------------------------------*/
static const float one_by_sqrt3 = 0.57735026919f;
static const float sqrt3_by_2 = 0.86602540378;
/* Private variables ---------------------------------------------------------*/
//Local view of DRV registers
//@TODO: Include these in motor object instead
static DRV_SPI_8301_Vars_t gate_driver_regs[2/*num_motors*/];
//Log to store the timing of calls to check_timing
//This is used in various places, so be sure to look for all the places it is written
#define TIMING_LOG_SIZE 32
static volatile uint16_t timing_logs[2/*num_motors*/][TIMING_LOG_SIZE];
static volatile int timing_log_index[2/*num_motors*/] = {0, 0};
/* Private function prototypes -----------------------------------------------*/
static void DRV8301_setup(Motor_t* motor, DRV_SPI_8301_Vars_t* local_regs);
static void start_adc_pwm();
static void start_pwm(TIM_HandleTypeDef* htim);
static void sync_timers(TIM_HandleTypeDef* htim_a, TIM_HandleTypeDef* htim_b,
uint16_t TIM_CLOCKSOURCE_ITRx, uint16_t count_offset);
static float phase_current_from_adcval(uint32_t ADCValue, int motornum);
static uint16_t check_timing(TIM_HandleTypeDef* htim, volatile uint16_t* log, volatile int* idx);
static void queue_voltage_timings(Motor_t* motor, float v_alpha, float v_beta);
static float measure_phase_resistance(Motor_t* motor, float test_current, float max_voltage);
static float measure_phase_inductance(Motor_t* motor, float voltage_low, float voltage_high);
static int16_t calib_enc_offset(Motor_t* motor, float voltage_magnitude);
/* Function implementations --------------------------------------------------*/
// Initalises the low level motor control and then starts the motor control threads
void init_motor_control() {
//Init gate drivers
DRV8301_setup(&motors[0], &gate_driver_regs[0]);
DRV8301_setup(&motors[1], &gate_driver_regs[1]);
// Start PWM and enable adc interrupts/callbacks
start_adc_pwm();
// Start Encoders
HAL_TIM_Encoder_Start(&htim3, TIM_CHANNEL_ALL);
HAL_TIM_Encoder_Start(&htim4, TIM_CHANNEL_ALL);
//Wait for current sense calibration to converge
//@TODO make timing a function of calibration filter tau
osDelay(1500);
}
//@TODO make available from anywhere
void safe_assert(int arg) {
if(!arg) {
htim1.Instance->BDTR &= ~(TIM_BDTR_MOE);
htim8.Instance->BDTR &= ~(TIM_BDTR_MOE);
for(;;);
}
}
// Set up the gate drivers
//@TODO stick DRV_SPI_8301_Vars_t in motor
static void DRV8301_setup(Motor_t* motor, DRV_SPI_8301_Vars_t* local_regs) {
for (int i = 0; i < num_motors; ++i) {
DRV8301_enable(&motor->gate_driver);
DRV8301_setupSpi(&motor->gate_driver, local_regs);
//@TODO we can use reporting only if we actually wire up the nOCTW pin
local_regs->Ctrl_Reg_1.OC_MODE = DRV8301_OcMode_LatchShutDown;
//Overcurrent set to approximately 150A at 100degC. This may need tweaking.
local_regs->Ctrl_Reg_1.OC_ADJ_SET = DRV8301_VdsLevel_0p730_V;
//20V/V on 500uOhm gives a range of +/- 150A
//40V/V on 500uOhm gives a range of +/- 75A
local_regs->Ctrl_Reg_2.GAIN = DRV8301_ShuntAmpGain_40VpV;
local_regs->SndCmd = true;
DRV8301_writeData(&motor->gate_driver, local_regs);
local_regs->RcvCmd = true;
DRV8301_readData(&motor->gate_driver, local_regs);
}
}
static void start_adc_pwm(){
//Enable ADC and interrupts
__HAL_ADC_ENABLE(&hadc1);
__HAL_ADC_ENABLE(&hadc2);
__HAL_ADC_ENABLE(&hadc3);
//Warp field stabilize.
osDelay(2);
__HAL_ADC_ENABLE_IT(&hadc1, ADC_IT_JEOC);
__HAL_ADC_ENABLE_IT(&hadc2, ADC_IT_JEOC);
__HAL_ADC_ENABLE_IT(&hadc3, ADC_IT_JEOC);
__HAL_ADC_ENABLE_IT(&hadc2, ADC_IT_EOC);
__HAL_ADC_ENABLE_IT(&hadc3, ADC_IT_EOC);
//Ensure that debug halting of the core doesn't leave the motor PWM running
__HAL_DBGMCU_FREEZE_TIM1();
__HAL_DBGMCU_FREEZE_TIM8();
//Turn off the regular conversion trigger for the inital phase
hadc2.Instance->CR2 &= ~ADC_CR2_EXTEN;
hadc3.Instance->CR2 &= ~ADC_CR2_EXTEN;
start_pwm(&htim1);
start_pwm(&htim8);
//TODO: explain why this offset
sync_timers(&htim1, &htim8, TIM_CLOCKSOURCE_ITR0, TIM_PERIOD_CLOCKS/2 - 1*128);
}
static void start_pwm(TIM_HandleTypeDef* htim){
//Init PWM
int half_load = TIM_PERIOD_CLOCKS/2;
htim->Instance->CCR1 = half_load;
htim->Instance->CCR2 = half_load;
htim->Instance->CCR3 = half_load;
//This hardware obfustication layer really is getting on my nerves
HAL_TIM_PWM_Start(htim, TIM_CHANNEL_1);
HAL_TIMEx_PWMN_Start(htim, TIM_CHANNEL_1);
HAL_TIM_PWM_Start(htim, TIM_CHANNEL_2);
HAL_TIMEx_PWMN_Start(htim, TIM_CHANNEL_2);
HAL_TIM_PWM_Start(htim, TIM_CHANNEL_3);
HAL_TIMEx_PWMN_Start(htim, TIM_CHANNEL_3);
htim->Instance->CCR4 = 1;
HAL_TIM_PWM_Start_IT(htim, TIM_CHANNEL_4);
}
static void sync_timers(TIM_HandleTypeDef* htim_a, TIM_HandleTypeDef* htim_b,
uint16_t TIM_CLOCKSOURCE_ITRx, uint16_t count_offset) {
//Store intial timer configs
uint16_t MOE_store_a = htim_a->Instance->BDTR & (TIM_BDTR_MOE);
uint16_t MOE_store_b = htim_b->Instance->BDTR & (TIM_BDTR_MOE);
uint16_t CR2_store = htim_a->Instance->CR2;
uint16_t SMCR_store = htim_b->Instance->SMCR;
//Turn off output
htim_a->Instance->BDTR &= ~(TIM_BDTR_MOE);
htim_b->Instance->BDTR &= ~(TIM_BDTR_MOE);
// Disable both timer counters
htim_a->Instance->CR1 &= ~TIM_CR1_CEN;
htim_b->Instance->CR1 &= ~TIM_CR1_CEN;
// Set first timer to send TRGO on counter enable
htim_a->Instance->CR2 &= ~TIM_CR2_MMS;
htim_a->Instance->CR2 |= TIM_TRGO_ENABLE;
// Set Trigger Source of second timer to the TRGO of the first timer
htim_b->Instance->SMCR &= ~TIM_SMCR_TS;
htim_b->Instance->SMCR |= TIM_CLOCKSOURCE_ITRx;
// Set 2nd timer to start on trigger
htim_b->Instance->SMCR &= ~TIM_SMCR_SMS;
htim_b->Instance->SMCR |= TIM_SLAVEMODE_TRIGGER;
// Dir bit is read only in center aligned mode, so we clear the mode for now
uint16_t CMS_store_a = htim_a->Instance->CR1 & TIM_CR1_CMS;
uint16_t CMS_store_b = htim_b->Instance->CR1 & TIM_CR1_CMS;
htim_a->Instance->CR1 &= ~TIM_CR1_CMS;
htim_b->Instance->CR1 &= ~TIM_CR1_CMS;
// Set both timers to up-counting state
htim_a->Instance->CR1 &= ~TIM_CR1_DIR;
htim_b->Instance->CR1 &= ~TIM_CR1_DIR;
// Restore center aligned mode
htim_a->Instance->CR1 |= CMS_store_a;
htim_b->Instance->CR1 |= CMS_store_b;
// set counter offset
htim_a->Instance->CNT = count_offset;
htim_b->Instance->CNT = 0;
// Start Timer a
htim_a->Instance->CR1 |= (TIM_CR1_CEN);
// Restore timer configs
htim_a->Instance->CR2 = CR2_store;
htim_b->Instance->SMCR = SMCR_store;
//restore output
htim_a->Instance->BDTR |= MOE_store_a;
htim_b->Instance->BDTR |= MOE_store_b;
}
static float phase_current_from_adcval(uint32_t ADCValue, int motornum) {
float rev_gain;
//@TODO we can shave off some clock cycles by writing a static rev_gain in the motor struct
//when we set the gains
switch (gate_driver_regs[motornum].Ctrl_Reg_2.GAIN) {
case DRV8301_ShuntAmpGain_10VpV:
rev_gain = 1.0f/10.0f;
break;
case DRV8301_ShuntAmpGain_20VpV:
rev_gain = 1.0f/20.0f;
break;
case DRV8301_ShuntAmpGain_40VpV:
rev_gain = 1.0f/40.0f;
break;
case DRV8301_ShuntAmpGain_80VpV:
rev_gain = 1.0f/80.0f;
break;
default:
rev_gain = 0.0f; //to stop warning
safe_assert(0);
}
int adcval_bal = (int)ADCValue - (1<<11);
float amp_out_volt = (3.3f/(float)(1<<12)) * (float)adcval_bal;
float shunt_volt = amp_out_volt * rev_gain;
float current = shunt_volt * motors[motornum].shunt_conductance;
return current;
}
void vbus_sense_adc_cb(ADC_HandleTypeDef* hadc) {
static const float voltage_scale = 3.3 * 11.0f / (float)(1<<12);
//Only one conversion in sequence, so only rank1
uint32_t ADCValue = HAL_ADCEx_InjectedGetValue(hadc, ADC_INJECTED_RANK_1);
vbus_voltage = ADCValue * voltage_scale;
}
// This is the callback from the ADC that we expect after the PWM has triggered an ADC conversion.
//@TODO: Document how the phasing is done, link to timing diagram
void pwm_trig_adc_cb(ADC_HandleTypeDef* hadc) {
#define calib_tau 0.2f //@TOTO make more easily configurable
static const float calib_filter_k = CURRENT_MEAS_PERIOD / calib_tau;
//Ensure ADCs are expected ones to simplify the logic below
safe_assert(hadc == &hadc2 || hadc == &hadc3);
bool current_meas_not_DC_CAL;
Motor_t* motor;
// Check if this trigger was the CC4 channel, used for actual current measurement at SVM vector 0
// or the update trigger, which is used for DC_CAL measurement at SVM vector 7
// M1 DC_CAL is a special case since due to hardware limitations, it uses the "regular" conversions
// rather than the injected ones.
uint32_t inj_src = hadc->Instance->CR2 & ADC_CR2_JEXTSEL;
uint32_t reg_edge = hadc->Instance->CR2 & ADC_CR2_EXTEN;
if (reg_edge != ADC_EXTERNALTRIGCONVEDGE_NONE) {
//We are measuring M1 DC_CAL here
current_meas_not_DC_CAL = false;
motor = &motors[1];
//Next measurement on this motor will be M1 current measurement
HAL_GPIO_WritePin(M1_DC_CAL_GPIO_Port, M1_DC_CAL_Pin, GPIO_PIN_RESET);
//Next measurement on this ADC will be M0 current
hadc->Instance->CR2 &= ~(ADC_CR2_JEXTEN | ADC_CR2_EXTEN | ADC_CR2_JEXTSEL);
hadc->Instance->CR2 |= (ADC_EXTERNALTRIGINJECCONVEDGE_RISING | ADC_EXTERNALTRIGINJECCONV_T1_CC4);
//Set ADC channels for next measurement
hadc->Instance->JSQR &= ~ADC_JSQR(ADC_JSQR_JSQ1, 1, 1);
hadc->Instance->JSQR |= ADC_JSQR((hadc == &hadc2) ? ADC_CHANNEL_10 : ADC_CHANNEL_11, 1, 1);
//Load next timings for M0 (only once is sufficient)
if (hadc == &hadc2) {
motors[0].motor_timer->Instance->CCR1 = motors[0].next_timings[0];
motors[0].motor_timer->Instance->CCR2 = motors[0].next_timings[1];
motors[0].motor_timer->Instance->CCR3 = motors[0].next_timings[2];
}
//Check the timing of the sequencing
check_timing(motor->motor_timer, timing_logs[1], &timing_log_index[1]);
} else if (inj_src == ADC_EXTERNALTRIGINJECCONV_T1_CC4) {
//We are measuring M0 current here
current_meas_not_DC_CAL = true;
motor = &motors[0];
//Next measurement on this motor will be M0 DC_CAL measurement
HAL_GPIO_WritePin(M0_DC_CAL_GPIO_Port, M0_DC_CAL_Pin, GPIO_PIN_SET);
//Next measurement on this ADC will be M1 current
hadc->Instance->CR2 &= ~(ADC_CR2_JEXTEN | ADC_CR2_EXTEN | ADC_CR2_JEXTSEL);
hadc->Instance->CR2 |= (ADC_EXTERNALTRIGINJECCONVEDGE_RISING | ADC_EXTERNALTRIGINJECCONV_T8_CC4);
//Set ADC channels for next measurement
hadc->Instance->JSQR &= ~ADC_JSQR(ADC_JSQR_JSQ1, 1, 1);
hadc->Instance->JSQR |= ADC_JSQR((hadc == &hadc2) ? ADC_CHANNEL_13 : ADC_CHANNEL_12, 1, 1);
//Load next timings for M1 (only once is sufficient)
if (hadc == &hadc2) {
motors[1].motor_timer->Instance->CCR1 = motors[1].next_timings[0];
motors[1].motor_timer->Instance->CCR2 = motors[1].next_timings[1];
motors[1].motor_timer->Instance->CCR3 = motors[1].next_timings[2];
}
//Check the timing of the sequencing
check_timing(motor->motor_timer, timing_logs[0], &timing_log_index[0]);
} else if (inj_src == ADC_EXTERNALTRIGINJECCONV_T8_CC4) {
//We are measuring M1 current here
current_meas_not_DC_CAL = true;
motor = &motors[1];
//Next measurement on this motor will be M1 DC_CAL measurement
HAL_GPIO_WritePin(M1_DC_CAL_GPIO_Port, M1_DC_CAL_Pin, GPIO_PIN_SET);
//Next measurement on this ADC will be M0 DC_CAL
hadc->Instance->CR2 &= ~(ADC_CR2_JEXTEN | ADC_CR2_EXTEN | ADC_CR2_JEXTSEL);
hadc->Instance->CR2 |= (ADC_EXTERNALTRIGINJECCONVEDGE_RISING | ADC_EXTERNALTRIGINJECCONV_T1_TRGO);
//Set ADC channels for next measurement
hadc->Instance->JSQR &= ~ADC_JSQR(ADC_JSQR_JSQ1, 1, 1);
hadc->Instance->JSQR |= ADC_JSQR((hadc == &hadc2) ? ADC_CHANNEL_10 : ADC_CHANNEL_11, 1, 1);
//Check the timing of the sequencing
check_timing(motor->motor_timer, timing_logs[1], &timing_log_index[1]);
} else if (inj_src == ADC_EXTERNALTRIGINJECCONV_T1_TRGO) {
//We are measuring M0 DC_CAL here
current_meas_not_DC_CAL = false;
motor = &motors[0];
//Next measurement on this motor will be M0 current measurement
HAL_GPIO_WritePin(M0_DC_CAL_GPIO_Port, M0_DC_CAL_Pin, GPIO_PIN_RESET);
//Next measurement on this ADC will be M1 DC_CAL
hadc->Instance->CR2 &= ~(ADC_CR2_JEXTEN | ADC_CR2_EXTEN | ADC_CR2_JEXTSEL);
hadc->Instance->CR2 |= ADC_EXTERNALTRIGCONVEDGE_RISING;
//Set ADC channels for next measurement
hadc->Instance->JSQR &= ~ADC_JSQR(ADC_JSQR_JSQ1, 1, 1);
hadc->Instance->JSQR |= ADC_JSQR((hadc == &hadc2) ? ADC_CHANNEL_13 : ADC_CHANNEL_12, 1, 1);
//Check the timing of the sequencing
check_timing(motor->motor_timer, timing_logs[0], &timing_log_index[0]);
} else {
safe_assert(0);
}
uint32_t ADCValue;
if (reg_edge != ADC_EXTERNALTRIGCONVEDGE_NONE) {
ADCValue = HAL_ADC_GetValue(hadc);
} else {
ADCValue = HAL_ADCEx_InjectedGetValue(hadc, ADC_INJECTED_RANK_1);
}
//@TODO remove hardcoded motornum
float current = phase_current_from_adcval(ADCValue, 0);
if (current_meas_not_DC_CAL) {
// ADC2 and ADC3 record the phB and phC currents concurrently,
// and their interrupts should arrive on the same clock cycle.
// We dispatch the callbacks in order, so ADC2 will always be processed before ADC3.
// Therefore we store the value from ADC2 and signal the thread that the
// measurement is ready when we recieve the ADC3 measurement
//return or continue
if (hadc == &hadc2) {
motor->current_meas.phB = current - motor->DC_calib.phB;
return;
} else {
motor->current_meas.phC = current - motor->DC_calib.phC;
}
// Trigger motor thread
if (motor->thread_ready)
osSignalSet(motor->motor_thread, M_SIGNAL_PH_CURRENT_MEAS);
} else {
// DC_CAL measurement
if (hadc == &hadc2) {
motor->DC_calib.phB += (current - motor->DC_calib.phB) * calib_filter_k;
} else {
motor->DC_calib.phC += (current - motor->DC_calib.phC) * calib_filter_k;
}
}
}
static uint16_t check_timing(TIM_HandleTypeDef* htim, volatile uint16_t* log, volatile int* idx) {
uint16_t timing = htim->Instance->CNT;
bool down = htim->Instance->CR1 & TIM_CR1_DIR;
if (down) {
uint16_t delta = TIM_PERIOD_CLOCKS - timing;
timing = TIM_PERIOD_CLOCKS + delta;
}
if (log != NULL && idx != NULL) {
if(++(*idx) == TIMING_LOG_SIZE)
*idx = 0;
log[*idx] = timing;
}
return timing;
}
static float measure_phase_resistance(Motor_t* motor, float test_current, float max_voltage) {
static const float kI = 10.0f; //[(V/s)/A]
static const int num_test_cycles = 3.0f / CURRENT_MEAS_PERIOD;
float test_voltage = 0.0f;
for (int i = 0; i < num_test_cycles; ++i) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
float Ialpha = -0.5f * (motor->current_meas.phB + motor->current_meas.phC);
test_voltage += (kI * CURRENT_MEAS_PERIOD) * (test_current - Ialpha);
if (test_voltage > max_voltage) test_voltage = max_voltage;
if (test_voltage < -max_voltage) test_voltage = -max_voltage;
//Test voltage along phase A
queue_voltage_timings(motor, test_voltage, 0.0f);
//Check we meet deadlines after queueing
safe_assert(check_timing(motor->motor_timer, NULL, NULL) < motor->control_deadline);
}
//De-energize motor
queue_voltage_timings(motor, 0.0f, 0.0f);
float phase_resistance = test_voltage / test_current;
return phase_resistance;
}
static void queue_modulation_timings(Motor_t* motor, float mod_alpha, float mod_beta) {
float tA, tB, tC;
SVM(mod_alpha, mod_beta, &tA, &tB, &tC);
motor->next_timings[0] = (uint16_t)(tA * (float)TIM_PERIOD_CLOCKS);
motor->next_timings[1] = (uint16_t)(tB * (float)TIM_PERIOD_CLOCKS);
motor->next_timings[2] = (uint16_t)(tC * (float)TIM_PERIOD_CLOCKS);
}
static void queue_voltage_timings(Motor_t* motor, float v_alpha, float v_beta) {
float vfactor = 1.0f / ((2.0f / 3.0f) * vbus_voltage);
float mod_alpha = vfactor * v_alpha;
float mod_beta = vfactor * v_beta;
queue_modulation_timings(motor, mod_alpha, mod_beta);
}
static float measure_phase_inductance(Motor_t* motor, float voltage_low, float voltage_high) {
float test_voltages[2] = {voltage_low, voltage_high};
float Ialphas[2] = {0.0f};
static const int num_cycles = 5000;
for (int t = 0; t < num_cycles; ++t) {
for (int i = 0; i < 2; ++i) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
Ialphas[i] += -motor->current_meas.phB - motor->current_meas.phC;
//Test voltage along phase A
queue_voltage_timings(motor, test_voltages[i], 0.0f);
//Check we meet deadlines after queueing
safe_assert(check_timing(motor->motor_timer, NULL, NULL) < motor->control_deadline);
}
}
float v_L = 0.5f * (voltage_high - voltage_low);
//Note: A more correct formula would also take into account that there is a finite timestep.
//However, the discretisation in the current control loop inverts the same discrepancy
float dI_by_dt = (Ialphas[1] - Ialphas[0]) / (CURRENT_MEAS_PERIOD * (float)num_cycles);
float L = v_L / dI_by_dt;
return L;
}
//TODO: Do the scan with current, not voltage!
//TODO: add check_timing
static int16_t calib_enc_offset(Motor_t* motor, float voltage_magnitude) {
static const float start_lock_duration = 1.0f;
static const int num_steps = 1024;
static const float dt_step = 1.0f/500.0f;
static const float scan_range = 4.0f * M_PI;
const float step_size = scan_range / (float)num_steps; //TODO handle const expressions better (maybe switch to C++ ?)
int32_t encvaluesum = 0;
//go to rotor zero phase for 2s to get ready to scan
for (int i = 0; i < start_lock_duration*CURRENT_MEAS_HZ; ++i) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
queue_voltage_timings(motor, voltage_magnitude, 0.0f);
}
//scan forwards
for (float ph = -scan_range / 2.0f; ph < scan_range / 2.0f; ph += step_size) {
for (int i = 0; i < dt_step*(float)CURRENT_MEAS_HZ; ++i) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
float v_alpha = voltage_magnitude * arm_cos_f32(ph);
float v_beta = voltage_magnitude * arm_sin_f32(ph);
queue_voltage_timings(motor, v_alpha, v_beta);
}
//TODO actual unit conversion
encvaluesum += (int16_t)motor->rotor.encoder_timer->Instance->CNT;
}
//check direction
//TODO ability to handle both encoder directions
safe_assert((int16_t)motor->rotor.encoder_timer->Instance->CNT > 0);
//scan backwards
for (float ph = scan_range / 2.0f; ph > -scan_range / 2.0f; ph -= step_size) {
for (int i = 0; i < dt_step*(float)CURRENT_MEAS_HZ; ++i) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
float v_alpha = voltage_magnitude * arm_cos_f32(ph);
float v_beta = voltage_magnitude * arm_sin_f32(ph);
queue_voltage_timings(motor, v_alpha, v_beta);
}
//TODO actual unit conversion
encvaluesum += (int16_t)motor->rotor.encoder_timer->Instance->CNT;
}
int16_t offset = encvaluesum / (num_steps * 2);
return offset;
}
static void scan_motor_loop(Motor_t* motor, float omega, float voltage_magnitude) {
for(;;) {
for (float ph = 0.0f; ph < 2.0f * M_PI; ph += omega * CURRENT_MEAS_PERIOD) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
float v_alpha = voltage_magnitude * arm_cos_f32(ph);
float v_beta = voltage_magnitude * arm_sin_f32(ph);
queue_voltage_timings(motor, v_alpha, v_beta);
//Check we meet deadlines after queueing
safe_assert(check_timing(motor->motor_timer, NULL, NULL) < motor->control_deadline);
}
}
}
static void update_rotor(Rotor_t* rotor) {
//@TODO stick parameter into struct
#define QCPR (600*4)
static const float elec_rad_per_enc = 7.0 * 2 * M_PI * (1.0f / (float)QCPR);
//update internal encoder state
int16_t delta_enc = (int16_t)rotor->encoder_timer->Instance->CNT - (int16_t)rotor->encoder_state;
rotor->encoder_state += (int32_t)delta_enc;
//compute electrical phase
float ph = elec_rad_per_enc * ((rotor->encoder_state % QCPR) - rotor->encoder_offset);
ph = fmodf(ph, 2*M_PI);
rotor->phase = ph;
//run pll (for now pll is in units of encoder counts)
//@TODO pll_pos runs out of precision very quickly here! Perhaps decompose into integer and fractional part?
// Predict current pos
rotor->pll_pos += CURRENT_MEAS_PERIOD * rotor->pll_vel;
// discrete phase detector
float delta_pos = (float)(rotor->encoder_state - (int32_t)floorf(rotor->pll_pos));
// pll feedback
rotor->pll_pos += CURRENT_MEAS_PERIOD * rotor->pll_kp * delta_pos;
rotor->pll_vel += CURRENT_MEAS_PERIOD * rotor->pll_ki * delta_pos;
}
static void FOC_voltage_loop(Motor_t* motor, float v_d, float v_q) {
for (;;) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
update_rotor(&motor->rotor);
float c = arm_cos_f32(motor->rotor.phase);
float s = arm_sin_f32(motor->rotor.phase);
float v_alpha = c*v_d - s*v_q;
float v_beta = c*v_q + s*v_d;
queue_voltage_timings(motor, v_alpha, v_beta);
//Check we meet deadlines after queueing
safe_assert(check_timing(motor->motor_timer, NULL, NULL) < motor->control_deadline);
}
}
static void FOC_current(Motor_t* motor, float Id_des, float Iq_des) {
Current_control_t* ictrl = &motor->current_control;
//Clarke transform
float Ialpha = -motor->current_meas.phB - motor->current_meas.phC;
float Ibeta = one_by_sqrt3 * (motor->current_meas.phB - motor->current_meas.phC);
//Park transform
float c = arm_cos_f32(motor->rotor.phase);
float s = arm_sin_f32(motor->rotor.phase);
float Id = c*Ialpha + s*Ibeta;
float Iq = c*Ibeta - s*Ialpha;
//Current error
float Ierr_d = Id_des - Id;
float Ierr_q = Iq_des - Iq;
//@TODO look into feed forward terms (esp omega, since PI pole maps to RL tau)
//@TODO current limit
//Apply PI control
float Vd = ictrl->v_current_control_integral_d + Ierr_d * ictrl->p_gain;
float Vq = ictrl->v_current_control_integral_q + Ierr_q * ictrl->p_gain;
float vfactor = 1.0f / ((2.0f / 3.0f) * vbus_voltage);
float mod_d = vfactor * Vd;
float mod_q = vfactor * Vq;
//Vector modulation saturation, lock integrator if saturated
//@TODO make maximum modulation configurable (currently 40%)
float mod_scalefactor = 0.20f * sqrt3_by_2 * 1.0f/sqrtf(mod_d*mod_d + mod_q*mod_q);
if (mod_scalefactor < 1.0f)
{
mod_d *= mod_scalefactor;
mod_q *= mod_scalefactor;
} else {
//@TODO look into fancier anti integrator windup than simple locking
ictrl->v_current_control_integral_d += Ierr_d * (ictrl->i_gain * CURRENT_MEAS_PERIOD);
ictrl->v_current_control_integral_q += Ierr_q * (ictrl->i_gain * CURRENT_MEAS_PERIOD);
}
// Compute estimated bus current
// *IbusEst = mod_d * Id + mod_q * Iq;
// Inverse park transform
float mod_alpha = c*mod_d - s*mod_q;
float mod_beta = c*mod_q + s*mod_d;
// Apply SVM
queue_modulation_timings(motor, mod_alpha, mod_beta);
//Check we meet deadlines after queueing
safe_assert(check_timing(motor->motor_timer, NULL, NULL) < motor->control_deadline);
}
static void FOC_current_loop(Motor_t* motor, float Id_des, float Iq_des) {
for (;;) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
update_rotor(&motor->rotor);
FOC_current(motor, Id_des, Iq_des);
}
}
static void control_velocity_loop(Motor_t* motor, float test_vel) {
static const float k_vel = 5.0f / 10000.0f; // [A/(counts/s)]
for (;;) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
update_rotor(&motor->rotor);
float v_err = test_vel - motor->rotor.pll_vel;
float Iq = k_vel * v_err;
float Ilim = motor->current_control.current_lim;
if (Iq > Ilim) Iq = Ilim;
if (Iq < -Ilim) Iq = -Ilim;
FOC_current(motor, 0.0f, Iq);
}
}
static void control_position_loop(Motor_t* motor, float test_pos) {
static const float k_pos = 20.0f; // [(counts/s) / counts]
static const float k_vel = 5.0f / 10000.0f; // [A/(counts/s)]
static const float vel_lim = 10000.0f; // [counts/s]
for (;;) {
osSignalWait(M_SIGNAL_PH_CURRENT_MEAS, osWaitForever);
update_rotor(&motor->rotor);
//Position control
//@TODO Decide if we want to use encoder or pll position here
float pos_err = test_pos - motor->rotor.pll_pos;
float vel_des = k_pos * pos_err;
if (vel_des > vel_lim) vel_des = vel_lim;
if (vel_des < -vel_lim) vel_des = -vel_lim;
//Velocity control
float v_err = vel_des - motor->rotor.pll_vel;
float Iq = k_vel * v_err;
float Ilim = motor->current_control.current_lim;
if (Iq > Ilim) Iq = Ilim;
if (Iq < -Ilim) Iq = -Ilim;
FOC_current(motor, 0.0f, Iq);
}
}
void motor_thread(void const * argument) {
Motor_t* motor = (Motor_t*)argument;
motor->motor_thread = osThreadGetId();
motor->thread_ready = true;
float test_current = 4.0f;
float R = measure_phase_resistance(motor, test_current, 1.0f);
float L = measure_phase_inductance(motor, -1.0f, 1.0f);
motor->rotor.encoder_offset = calib_enc_offset(motor, test_current * R);
//Only run tests on M0 for now
if (motor == &motors[1]) {
FOC_voltage_loop(motor, 0.0f, 0.0f);
}
//Calculate current control gains
float current_control_bandwidth = 2000.0f; // [rad/s]
motor->current_control.p_gain = current_control_bandwidth * L;
float plant_pole = R/L;
motor->current_control.i_gain = plant_pole * motor->current_control.p_gain;
//Calculate rotor pll gains
float rotor_pll_bandwidth = 2000.0f; // [rad/s]
motor->rotor.pll_kp = 2.0f * rotor_pll_bandwidth;
//Check that we don't get problems with discrete time approximation
safe_assert(CURRENT_MEAS_PERIOD * motor->rotor.pll_kp < 1.0f);
//Critically damped
motor->rotor.pll_ki = 0.25f * (motor->rotor.pll_kp * motor->rotor.pll_kp);
// scan_motor(motor, 50.0f, test_current * R);
// FOC_voltage_loop(motor, 0.0f, 0.8f);
FOC_current_loop(motor, 0.0f, 0.0f);
// static const float test_vel = 10000.0f; // [counts/s]
// control_velocity_loop(motor, test_vel);
// static const float test_pos = 10000.0f; // [counts]
// control_position_loop(motor, test_pos);
//De-energize motor
queue_voltage_timings(motor, 0.0f, 0.0f);
}
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