STM3 ESC dual brushless motor controller. 10-60v, motor power rating tiny to kW. Ganged or independent motor control As used in 'The Brute' locomotive - www.jons-workshop.com
Dependencies: mbed BufferedSerial Servo FastPWM
brushless_motor.cpp
- Committer:
- JonFreeman
- Date:
- 2019-03-04
- Revision:
- 12:d1d21a2941ef
- Parent:
- 11:bfb73f083009
File content as of revision 12:d1d21a2941ef:
// Cloned from 'DualBLS2018_06' on 23 November 2018
#include "mbed.h"
//#include "users/mbed_official/code/mbed-dev/file/707f6e361f3e/targets/TARGET_STM/TARGET_STM32F4/TARGET_STM32F401xE/device/stm32f401xe.h"
#include "stm32f401xe.h"
#include "DualBLS.h"
#include "BufferedSerial.h"
#include "FastPWM.h"
#include "Servo.h"
#include "brushless_motor.h"
extern eeprom_settings mode ;
extern double rpm2mph ;
extern BufferedSerial pc; // The two com ports used. There is also an unused com port, com3 setup @ 1200 baud
brushless_motor::brushless_motor (PinName iadc, PinName pwv, PinName pwi,
const uint16_t * lutptr, PinName px, PinName py, PinName pz, PortName pn, int port_bit_mask, uint32_t rnum)
: Motor_I(iadc), maxV(pwv,PWM_PRESECALER_DEFAULT), maxI(pwi,PWM_PRESECALER_DEFAULT), H1(px), H2(py), H3(pz), OP(pn, port_bit_mask) // Constructor
{
// Constructor
OP = 0;
H1.mode (PullUp); // PullUp resistors enabled on all Hall sensor input pins
H2.mode (PullUp);
H3.mode (PullUp);
H1.rise (callback(this, &brushless_motor::Hall_change)); // Attach handler to the rising interruptIn edge
H1.fall (callback(this, &brushless_motor::Hall_change)); // Attach handler to the falling interruptIn edge
H2.rise (callback(this, &brushless_motor::Hall_change)); // Attach handler to the rising interruptIn edge
H2.fall (callback(this, &brushless_motor::Hall_change)); // Attach handler to the falling interruptIn edge
H3.rise (callback(this, &brushless_motor::Hall_change)); // Attach handler to the rising interruptIn edge
H3.fall (callback(this, &brushless_motor::Hall_change)); // Attach handler to the falling interruptIn edge
Hall_total = 0; // mode can be only 0, 8, 16 or 24, lut row select for Handbrake, Forward, Reverse, or Regen Braking
Hall_previous = 0;
maxV.period_ticks (MAX_PWM_TICKS + 1); // around 18 kHz
maxI.period_ticks (MAX_PWM_TICKS + 1);
maxV.pulsewidth_ticks (MAX_PWM_TICKS - 20); // Motor voltage pwm is inverted, see MCP1630 data
maxI.pulsewidth_ticks (MAX_PWM_TICKS / 30); // Motor current pwm is not inverted. Initial values for scope hanging test
visible_mode = MOTOR_REGENBRAKE;
inner_mode = MOTOR_REGENBRAKE;
lut = lutptr; // Pointer to motor energisation bit pattern table
current_sense_rs_offset = rnum; // This is position in mode.rd(current_sense_rs_offset)
Hall_index[0] = Hall_index[1] = read_Halls ();
tickleon = 0;
direction = 0;
angle_cnt = 0; // Incremented or decremented on each Hall event according to actual measured direction of travel
encoder_error_cnt = 0; // Incremented when Hall transition not recognised as either direction
last_V = last_I = 0.0;
Idbl = 0.0;
numof_current_sense_rs = 1.0;
RPM_filter = 0.0;
dv_by_dt = 0.0;
s[1] = 0.25;
s[2] = 9.0;
s[3] = 0.4;
s[4] = 0.2;
dRPM = 0.0;
V_clamp = 1.0 ; // Used to limit top speed
motor_poles = 8; // Default to 8 pole motor
#ifdef USING_DC_MOTORS
dc_motor = (Hall_index[0] == 7) ? true : false ;
#endif
}
/**
* void brushless_motor::sniff_current () { // Initiate ADC current reading
* This to be called in response to ticker timebase interrupt.
* As designed, called at 200 micro second intervals (Feb 2019)
* Updates double I.dbl current measured in milliamps
* Reading not used elsewhere in this code but made available through command line for external controller
*/
void brushless_motor::sniff_current () { // Initiate ADC current reading
const double sampweight = 0.01 ; /// (double)CURRENT_SAMPLES_AVERAGED ;
const double shrinkby = 1.0 - sampweight;
uint16_t samp = Motor_I.read_u16 (); // CHECK but thought to be called once per 200us for each motor - CORRECT Feb 2019
double dbls = ((double)samp) * numof_current_sense_rs / 6.0; // reading in mA
Idbl *= shrinkby; // Jan 2019 New recursive low pass filter
Idbl += dbls * sampweight; // Current reading available, however not certain this is of any real use
}
bool brushless_motor::poles (int p) { // Jan 2019 max_rom no longer used. target_speed is preferred
if (!max_rpm) { // Not been set since powerup
max_rpm = (uint32_t) (((double)mode.rd(TOP_SPEED) / rpm2mph) / 10.0) ;
target_speed = (double)mode.rd(TOP_SPEED) / 10.0;
numof_current_sense_rs = (double)mode.rd(current_sense_rs_offset);
pc.printf ("max_rpm=%d, tp speed=%.1f, rpm2mph=%.6f\r\n", max_rpm, target_speed, rpm2mph);
}
if (p == 4 || p == 6 || p == 8) {
motor_poles = p;
return true;
}
return false;
}
void brushless_motor::Hall_change () {
int32_t delta_theta;
const int32_t delta_theta_lut[] = { // Looks up -1 for forward move detected, +1 for reverse move detected, 0 for error or unknown
0, 0, 0, 0, 0, 0, 0, 0, // Previous Hindex was 0
0, 0, 0,-1, 0, 1, 0, 0, // Previous Hindex was 1
0, 0, 0, 1, 0, 0,-1, 0, // Previous Hindex was 2
0, 1,-1, 0, 0, 0, 0, 0, // Previous Hindex was 3
0, 0, 0, 0, 0,-1, 1, 0, // Previous Hindex was 4
0,-1, 0, 0, 1, 0, 0, 0, // Previous Hindex was 5
0, 0, 1, 0,-1, 0, 0, 0, // Previous Hindex was 6
0, 0, 0, 0, 0, 0, 0, 0, // Previous Hindex was 7
} ;
Hall_index[0] = read_Halls ();
delta_theta = delta_theta_lut[(Hall_index[1] << 3) | Hall_index[0]];
if (delta_theta == 0)
encoder_error_cnt++;
else
angle_cnt += delta_theta;
OP = lut[inner_mode | Hall_index[0]]; // changed mode to inner_mode 27/04/18
Hall_total++;
Hall_index[1] = Hall_index[0];
}
/**
* void brushless_motor::direction_set (int dir) {
* Used to set direction according to mode data from eeprom
*/
void brushless_motor::direction_set (int dir)
{
direction = (dir != 0) ? MOTOR_FORWARD | MOTOR_REVERSE : 0; // bits used in eor, FORWARD = 1<<3, REVERSE = 1<<4
}
int brushless_motor::read_Halls ()
{
int x = 0;
if (H1) x |= 1;
if (H2) x |= 2;
if (H3) x |= 4;
return x;
}
void brushless_motor::high_side_off () // Jan 2019 Only ever called from main when high side gate drive charge might need pumping up
{
uint16_t p = OP;
p &= lut[32]; // KEEP_L_MASK_A or B
OP = p;
}
/*
void brushless_motor::low_side_on ()
{
maxV.pulsewidth_ticks (1);
OP = lut[31]; // KEEP_L_MASK_A or B
}
*/
void brushless_motor::set_speed (double p) // Sets target_speed
{
target_speed = p;
}
/**
* void brushless_motor::set_V_limit (double p) // Sets max motor voltage.
*
* Set motor voltage limit from zero (p=0.0) to max link voltage (p=1.0)
*/
void brushless_motor::set_V_limit (double p) // Sets max motor voltage.
{
if (p < 0.0)
p = 0.0;
if (p > 1.0)
p = 1.0;
last_V = p; // Retains last voltage limit demanded by driver
if ((V_clamp < last_V) && (inner_mode == MOTOR_FORWARD || inner_mode == MOTOR_REVERSE)) // Jan 2019 limit top speed when driving
p = V_clamp; // If motor runnable, set voltage limit to lower of last_V and V_clamp
p *= 0.95; // need limit, ffi see MCP1630 data
p = 1.0 - p; // because pwm is wrong way up
maxV.pulsewidth_ticks ((int)(p * MAX_PWM_TICKS)); // PWM output to MCP1630 inverted motor pwm as MCP1630 inverts
}
/**void brushless_motor::set_I_limit (double p) // Sets max motor current. pwm integrated to dc ref voltage level
*
* Set motor current limit from zero (p=0.0) to max determined by current sense resistors (p=1.0)
* Value sent to pwm with RC integrator acting as AnalogOut.
* pwm capable of 0.0 <= V_out <= 3.3. This feeds MCP1630 V_Ref, range 0 to 2.7v
* Therefore (2.7/3.3) = 0.82 factor included.
* Jan 2019 - As yet uncalibrated, so let's have a go at working it out!
* Voltage ax current sense resistors amplified by op-amp with gain 5.7 (see EasyPC file 'BrushlessSTM3.sch', U6, R63, R64)
* This then put through pot divider (10k with 4k7 to ground, gain 0.32) reducing overall gain to 1.8 (accurate enough)
* This connects to MCP1630 CS (current sense) pin which works over the voltage range 0.0 to 0.9v
* Therefore 0.5v across current sense resistor is sufficient to turn driver off.
* 0.5v across 0.05 ohm gives 10A per current sense resistor fitted.
* ** NOTE ** This is fast acting cycle by cycle current limit, the 10A figure is therefore peak T_on current.
*
* Current flows through current sense reaistor when one high side and one low side switch are on, expect a rising ramp due to motor inductance.
* When either switch is off, inductor current continues to flow but not through current sense resistors, through a parasitic diode instead.
* Thus T_on current is measured, T_off current is not measured
* This means current reading should approximate to current taken from the supply. Motor average current may be considerably higher.
* During REGEN_BRAKING, current flows the 'wrong' way through sense resistors and can not be measured.
*
* Board designed to have 1, 2, 3 or 4 0R05 current sense resistors per motor for 10A, 20A, 30A or 40A peak motor currents
*/
void brushless_motor::set_I_limit (double p) // Sets max motor current. pwm integrated to dc ref voltage level
{
const uint32_t MPR = ((MAX_PWM_TICKS * 9) / 11); // Scales 3.3v pwm DAC output to 2.7v V_Ref input
if (p < 0.0)
p = 0.0;
if (p > 1.0)
p = 1.0;
last_I = p; // Retains last current limit demanded by driver
maxI.pulsewidth_ticks ((uint32_t)(p * MPR)); // PWM
}
/**
* void brushless_motor::speed_monitor_and_control () // ** CALL THIS 32 TIMES PER SECOND **
* Call this once per 'MAIN_LOOP_REPEAT_TIME_US= 31250' main loop pass to keep RPM and MPH figures correct
* Tracks total transitions on Hall sensor inputs to determine speed.
* Sets variables double dRPM of motor RPM, and double dMPH miles per hour
*
* Speed control - double target_speed as reference input. *
* ** This is where any speed limit gets applied **
* Motor voltage reduced when at or over speed. Does NOT apply any braking
* Scope for further improvement of control algorithm - crude implementation of PID with no I
*/
void brushless_motor::speed_monitor_and_control () // call this once per 'MAIN_LOOP_REPEAT_TIME_US= 31250' main loop pass to keep count = edges per sec
{
#ifdef USING_DC_MOTORS
if (dc_motor)
return 0;
#endif
// Feb 2019 - coefficients currently values in ram to allow for tweaking via command line. Will be 'const' once settled upon.
// const double samp_scale = 0.35; // Tweak this value only to tune filter
double samp_scale = s[1]; // Tweak this value only to tune filter
double shrink_by = 1.0 - samp_scale;
// const double dv_scale = 0.15;
double dv_scale = s[3];
double dv_shrink = 1.0 - dv_scale;
double speed_error, d, t;
uint32_t Hall_tot_copy = Hall_total; // Copy value for use throughout function as may get changed at any instant during exec !
moving_flag = true;
if (Hall_previous == Hall_tot_copy) { // Test for motor turning or not
moving_flag = false; // Zero Hall transitions since previous call - motor not moving
tickleon = TICKLE_TIMES; // May need to tickle some charge into high side switch bootstrap supplies
}
d = (double) ((Hall_tot_copy - Hall_previous) *640); // (Motor Hall sensor transitions in previous 31250us) * 640
d /= motor_poles; // d now true but lumpy 'RPM' during most recent 31250us corrected for number of motor poles
t = RPM_filter; // Value from last time around
RPM_filter *= shrink_by;
RPM_filter += (d * samp_scale); // filtered RPM
// RPM_filter[n] = shrink_by RPM_filter[n - 1] + samp_scale x[n]
t -= RPM_filter; // more like minus dv/dt
dv_by_dt *= dv_shrink;
dv_by_dt += (t * dv_scale); // filtered rate of change, the 'D' Differential contribution to PID control
dRPM += RPM_filter;
dRPM /= 2.0;
dMPH = RPM_filter * rpm2mph; // Completed updates of RPM and MPH
if (inner_mode == MOTOR_FORWARD || inner_mode == MOTOR_REVERSE) { // Speed control only makes sense when motor runnable
speed_error = (target_speed - dMPH) / 1000.0; // 'P' Proportional contribution to PID control
d = V_clamp + (speed_error * s[2]) + ((dv_by_dt / 1000.0) * s[4]); // Apply P+I+D (with I=0) control
if (d > 1.0) d = 1.0;
if (d < 0.0) d = 0.0;
V_clamp = d;
if (V_clamp < last_V) // Jan 2019 limit top speed when driving
{
d *= 0.95; // need limit, ffi see MCP1630 data
d = 1.0 - d; // because pwm is wrong way up
maxV.pulsewidth_ticks ((int)(d * MAX_PWM_TICKS)); // PWM output to MCP1630 inverted motor pwm as MCP1630 inverts
}
}
/* temp_tick++;
if (temp_tick > 35) { // one and a bit second
temp_tick = 0;
pc.printf ("RPM %.0f, %.3f, %.3f, %.2f, dv/dt%.3f\r\n", dRPM, RPM_filter, d, dMPH, dv_by_dt);
}
*/
Hall_previous = Hall_tot_copy;
}
bool brushless_motor::is_moving ()
{
return moving_flag;
}
/**
bool brushless_motor::set_mode (int m)
Use to set motor to one mode of HANDBRAKE, FORWARD, REVERSE, REGENBRAKE.
If this causes change of mode, also sets V and I to zero.
*/
bool brushless_motor::set_mode (int m)
{
if ((m != MOTOR_HANDBRAKE) && (m != MOTOR_FORWARD) && (m != MOTOR_REVERSE) && (m != MOTOR_REGENBRAKE)) {
// pc.printf ("Error in set_mode, invalid mode %d\r\n", m);
return false;
}
if (visible_mode != m) { // Mode change, kill volts and amps to be safe
set_V_limit (0.0);
set_I_limit (0.0);
visible_mode = m;
}
if (m == MOTOR_FORWARD || m == MOTOR_REVERSE)
m ^= direction;
inner_mode = m; // idea is to use inner_mode only in lut addressing, keep 'visible_mode' true regardless of setup data in eeprom
return true;
}
void brushless_motor::motor_set () // Energise Port with data determined by Hall sensors
{
Hall_index[0] = read_Halls ();
OP = lut[inner_mode | Hall_index[0]];
}