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Tracker: move servo control to servos.pde file

master
Randy Mackay 11 years ago
parent
643a680fed
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1135ef3610
2 changed files with 264 additions and 259 deletions
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  1. 264
      AntennaTracker/servos.pde
  2. 259
      AntennaTracker/tracking.pde

264
AntennaTracker/servos.pde
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@ -0,0 +1,264 @@ @@ -0,0 +1,264 @@
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
* servos.pde - code to move pitch and yaw servos to attain a target heading or pitch
*/
/**
update the pitch (elevation) servo. The aim is to drive the boards ahrs pitch to the
requested pitch, so the board (and therefore the antenna) will be pointing at the target
*/
static void update_pitch_position_servo(float pitch)
{
// degrees(ahrs.pitch) is -90 to 90, where 0 is horizontal
// pitch argument is -90 to 90, where 0 is horizontal
// servo_out is in 100ths of a degree
float ahrs_pitch = ahrs.pitch_sensor*0.01f;
int32_t err = (ahrs_pitch - pitch) * 100.0;
// Need to configure your servo so that increasing servo_out causes increase in pitch/elevation (ie pointing higher into the sky,
// above the horizon. On my antenna tracker this requires the pitch/elevation servo to be reversed
// param set RC2_REV -1
//
// The pitch servo (RC channel 2) is configured for servo_out of -9000-0-9000 servo_out,
// which will drive the servo from RC2_MIN to RC2_MAX usec pulse width.
// Therefore, you must set RC2_MIN and RC2_MAX so that your servo drives the antenna altitude between -90 to 90 exactly
// To drive my HS-645MG servos through their full 180 degrees of rotational range, I have to set:
// param set RC2_MAX 2540
// param set RC2_MIN 640
//
// You will also need to tune the pitch PID to suit your antenna and servos. I use:
// PITCH2SRV_P 0.100000
// PITCH2SRV_I 0.020000
// PITCH2SRV_D 0.000000
// PITCH2SRV_IMAX 4000.000000
int32_t new_servo_out = channel_pitch.servo_out - g.pidPitch2Srv.get_pid(err);
channel_pitch.servo_out = constrain_float(new_servo_out, -9000, 9000);
// add slew rate limit
if (g.pitch_slew_time > 0.02f) {
uint16_t max_change = 0.02f * 18000 / g.pitch_slew_time;
if (max_change < 1) {
max_change = 1;
}
new_servo_out = constrain_float(new_servo_out,
channel_pitch.servo_out - max_change,
channel_pitch.servo_out + max_change);
}
channel_pitch.servo_out = new_servo_out;
}
/**
update the pitch (elevation) servo. The aim is to drive the boards ahrs pitch to the
requested pitch, so the board (and therefore the antenna) will be pointing at the target
*/
static void update_pitch_onoff_servo(float pitch)
{
// degrees(ahrs.pitch) is -90 to 90, where 0 is horizontal
// pitch argument is -90 to 90, where 0 is horizontal
// servo_out is in 100ths of a degree
float ahrs_pitch = degrees(ahrs.pitch);
float err = ahrs_pitch - pitch;
float acceptable_error = g.onoff_pitch_rate * g.onoff_pitch_mintime;
if (fabsf(err) < acceptable_error) {
channel_pitch.servo_out = 0;
} else if (err > 0) {
// positive error means we are pointing too high, so push the
// servo down
channel_pitch.servo_out = -9000;
} else {
// negative error means we are pointing too low, so push the
// servo up
channel_pitch.servo_out = 9000;
}
}
/**
update the pitch (elevation) servo. The aim is to drive the boards ahrs pitch to the
requested pitch, so the board (and therefore the antenna) will be pointing at the target
*/
static void update_pitch_servo(float pitch)
{
switch ((enum ServoType)g.servo_type.get()) {
case SERVO_TYPE_ONOFF:
update_pitch_onoff_servo(pitch);
break;
case SERVO_TYPE_POSITION:
default:
update_pitch_position_servo(pitch);
break;
}
channel_pitch.calc_pwm();
channel_pitch.output();
}
/**
update the yaw (azimuth) servo. The aim is to drive the boards ahrs
yaw to the requested yaw, so the board (and therefore the antenna)
will be pointing at the target
*/
static void update_yaw_position_servo(float yaw)
{
int32_t ahrs_yaw_cd = wrap_180_cd(ahrs.yaw_sensor);
int32_t yaw_cd = wrap_180_cd(yaw*100);
const int16_t margin = 500; // 5 degrees slop
static uint16_t count = 0;
static uint32_t last_millis= 0;
uint32_t millis = hal.scheduler->millis();
if (millis > last_millis + 1000)
{
// hal.uartA->printf("ahrs_yaw_cd %ld yaw_cd %ld\n", ahrs_yaw_cd, yaw_cd);
// hal.uartA->printf("count %d\n", count);
last_millis = millis;
count = 0;
}
count++;
// Antenna as Ballerina. Use with antenna that do not have continuously rotating servos, ie at some point in rotation
// the servo limits are reached and the servo has to slew 360 degrees to the 'other side' to keep tracking.
//
// This algorithm accounts for the fact that the antenna mount may not be aligned with North
// (in fact, any alignment is permissable), and that the alignment may change (possibly rapidly) over time
// (as when the antenna is mounted on a moving, turning vehicle)
// When the servo is being forced beyond its limits, it rapidly slews to the 'other side' then normal tracking takes over.
//
// Caution: this whole system is compromised by the fact that the ahrs_yaw reported by the compass system lags
// the actual yaw by about 5 seconds, and also periodically realigns itself with about a 30 second period,
// which makes it very hard to be completely sure exactly where the antenna is _really_ pointing
// especially during the high speed slew. This can cause odd pointing artifacts from time to time. The best strategy is to
// position and point the mount so the aircraft does not 'go behind' the antenna (if possible)
//
// With my antenna mount, large pwm output drives the antenna anticlockise, so need:
// param set RC1_REV -1
// to reverse the servo. Yours may be different
//
// You MUST set RC1_MIN and RC1_MAX so that your servo drives the antenna azimuth from -180 to 180 relative
// to the mount.
// To drive my HS-645MG servos through their full 180 degrees of rotational range and therefore the
// antenna through a full 360 degrees, I have to set:
// param set RC1_MAX 2380
// param set RC1_MIN 680
// According to the specs at https://www.servocity.com/html/hs-645mg_ultra_torque.html,
// that should be 600 through 2400, but the azimuth gearing in my antenna pointer is not exactly 2:1
int32_t err = wrap_180_cd(ahrs_yaw_cd - yaw_cd);
/*
a positive error means that we need to rotate counter-clockwise
a negative error means that we need to rotate clockwise
Use our current yawspeed to determine if we are moving in the
right direction
*/
static int8_t slew_dir;
static uint32_t slew_start_ms;
int8_t new_slew_dir = slew_dir;
Vector3f earth_rotation = ahrs.get_gyro() * ahrs.get_dcm_matrix();
bool making_progress;
if (slew_dir != 0) {
making_progress = (-slew_dir * earth_rotation.z >= 0);
} else {
making_progress = (err * earth_rotation.z >= 0);
}
if (abs(channel_yaw.servo_out) == 18000 &&
abs(err) > margin &&
making_progress &&
hal.scheduler->millis() - slew_start_ms > g.min_reverse_time*1000) {
// we are at the limit of the servo and are not moving in the
// right direction, so slew the other way
new_slew_dir = -channel_yaw.servo_out / 18000;
slew_start_ms = hal.scheduler->millis();
}
/*
stop slewing and revert to normal control when normal control
should move us in the right direction
*/
if (slew_dir * err < -margin) {
new_slew_dir = 0;
}
if (new_slew_dir != slew_dir) {
gcs_send_text_fmt(PSTR("SLEW: %d/%d err=%ld servo=%ld ez=%.3f"),
(int)slew_dir, (int)new_slew_dir,
(long)err,
(long)channel_yaw.servo_out,
degrees(ahrs.get_gyro().z));
}
slew_dir = new_slew_dir;
int16_t new_servo_out;
if (slew_dir != 0) {
new_servo_out = slew_dir * 18000;
g.pidYaw2Srv.reset_I();
} else {
float servo_change = g.pidYaw2Srv.get_pid(err);
servo_change = constrain_float(servo_change, -18000, 18000);
new_servo_out = constrain_float(channel_yaw.servo_out - servo_change, -18000, 18000);
}
// add slew rate limit
if (g.yaw_slew_time > 0.02f) {
uint16_t max_change = 0.02f * 36000.0f / g.yaw_slew_time;
if (max_change < 1) {
max_change = 1;
}
new_servo_out = constrain_float(new_servo_out,
channel_yaw.servo_out - max_change,
channel_yaw.servo_out + max_change);
}
channel_yaw.servo_out = new_servo_out;
}
/**
update the yaw (azimuth) servo. The aim is to drive the boards ahrs
yaw to the requested yaw, so the board (and therefore the antenna)
will be pointing at the target
*/
static void update_yaw_onoff_servo(float yaw)
{
int32_t ahrs_yaw_cd = wrap_180_cd(ahrs.yaw_sensor);
int32_t yaw_cd = wrap_180_cd(yaw*100);
int32_t err_cd = wrap_180_cd(ahrs_yaw_cd - yaw_cd);
float err = err_cd * 0.01f;
float acceptable_error = g.onoff_yaw_rate * g.onoff_yaw_mintime;
if (fabsf(err) < acceptable_error) {
channel_yaw.servo_out = 0;
} else if (err > 0) {
// positive error means we are clockwise of the target, so
// move anti-clockwise
channel_yaw.servo_out = -18000;
} else {
// negative error means we are anti-clockwise of the target, so
// move clockwise
channel_yaw.servo_out = 18000;
}
}
/**
update the yaw (azimuth) servo.
*/
static void update_yaw_servo(float yaw)
{
switch ((enum ServoType)g.servo_type.get()) {
case SERVO_TYPE_ONOFF:
update_yaw_onoff_servo(yaw);
break;
case SERVO_TYPE_POSITION:
default:
update_yaw_position_servo(yaw);
break;
}
channel_yaw.calc_pwm();
channel_yaw.output();
}

259
AntennaTracker/tracking.pde
Unescape View File

@ -13,265 +13,6 @@ static struct { @@ -13,265 +13,6 @@ static struct {
float ground_speed; // vehicle's last known ground speed in m/s
} vehicle;
/**
update the pitch (elevation) servo. The aim is to drive the boards ahrs pitch to the
requested pitch, so the board (and therefore the antenna) will be pointing at the target
*/
static void update_pitch_position_servo(float pitch)
{
// degrees(ahrs.pitch) is -90 to 90, where 0 is horizontal
// pitch argument is -90 to 90, where 0 is horizontal
// servo_out is in 100ths of a degree
float ahrs_pitch = ahrs.pitch_sensor*0.01f;
int32_t err = (ahrs_pitch - pitch) * 100.0;
// Need to configure your servo so that increasing servo_out causes increase in pitch/elevation (ie pointing higher into the sky,
// above the horizon. On my antenna tracker this requires the pitch/elevation servo to be reversed
// param set RC2_REV -1
//
// The pitch servo (RC channel 2) is configured for servo_out of -9000-0-9000 servo_out,
// which will drive the servo from RC2_MIN to RC2_MAX usec pulse width.
// Therefore, you must set RC2_MIN and RC2_MAX so that your servo drives the antenna altitude between -90 to 90 exactly
// To drive my HS-645MG servos through their full 180 degrees of rotational range, I have to set:
// param set RC2_MAX 2540
// param set RC2_MIN 640
//
// You will also need to tune the pitch PID to suit your antenna and servos. I use:
// PITCH2SRV_P 0.100000
// PITCH2SRV_I 0.020000
// PITCH2SRV_D 0.000000
// PITCH2SRV_IMAX 4000.000000
int32_t new_servo_out = channel_pitch.servo_out - g.pidPitch2Srv.get_pid(err);
channel_pitch.servo_out = constrain_float(new_servo_out, -9000, 9000);
// add slew rate limit
if (g.pitch_slew_time > 0.02f) {
uint16_t max_change = 0.02f * 18000 / g.pitch_slew_time;
if (max_change < 1) {
max_change = 1;
}
new_servo_out = constrain_float(new_servo_out,
channel_pitch.servo_out - max_change,
channel_pitch.servo_out + max_change);
}
channel_pitch.servo_out = new_servo_out;
}
/**
update the pitch (elevation) servo. The aim is to drive the boards ahrs pitch to the
requested pitch, so the board (and therefore the antenna) will be pointing at the target
*/
static void update_pitch_onoff_servo(float pitch)
{
// degrees(ahrs.pitch) is -90 to 90, where 0 is horizontal
// pitch argument is -90 to 90, where 0 is horizontal
// servo_out is in 100ths of a degree
float ahrs_pitch = degrees(ahrs.pitch);
float err = ahrs_pitch - pitch;
float acceptable_error = g.onoff_pitch_rate * g.onoff_pitch_mintime;
if (fabsf(err) < acceptable_error) {
channel_pitch.servo_out = 0;
} else if (err > 0) {
// positive error means we are pointing too high, so push the
// servo down
channel_pitch.servo_out = -9000;
} else {
// negative error means we are pointing too low, so push the
// servo up
channel_pitch.servo_out = 9000;
}
}
/**
update the pitch (elevation) servo. The aim is to drive the boards ahrs pitch to the
requested pitch, so the board (and therefore the antenna) will be pointing at the target
*/
static void update_pitch_servo(float pitch)
{
switch ((enum ServoType)g.servo_type.get()) {
case SERVO_TYPE_ONOFF:
update_pitch_onoff_servo(pitch);
break;
case SERVO_TYPE_POSITION:
default:
update_pitch_position_servo(pitch);
break;
}
channel_pitch.calc_pwm();
channel_pitch.output();
}
/**
update the yaw (azimuth) servo. The aim is to drive the boards ahrs
yaw to the requested yaw, so the board (and therefore the antenna)
will be pointing at the target
*/
static void update_yaw_position_servo(float yaw)
{
int32_t ahrs_yaw_cd = wrap_180_cd(ahrs.yaw_sensor);
int32_t yaw_cd = wrap_180_cd(yaw*100);
const int16_t margin = 500; // 5 degrees slop
static uint16_t count = 0;
static uint32_t last_millis= 0;
uint32_t millis = hal.scheduler->millis();
if (millis > last_millis + 1000)
{
// hal.uartA->printf("ahrs_yaw_cd %ld yaw_cd %ld\n", ahrs_yaw_cd, yaw_cd);
// hal.uartA->printf("count %d\n", count);
last_millis = millis;
count = 0;
}
count++;
// Antenna as Ballerina. Use with antenna that do not have continuously rotating servos, ie at some point in rotation
// the servo limits are reached and the servo has to slew 360 degrees to the 'other side' to keep tracking.
//
// This algorithm accounts for the fact that the antenna mount may not be aligned with North
// (in fact, any alignment is permissable), and that the alignment may change (possibly rapidly) over time
// (as when the antenna is mounted on a moving, turning vehicle)
// When the servo is being forced beyond its limits, it rapidly slews to the 'other side' then normal tracking takes over.
//
// Caution: this whole system is compromised by the fact that the ahrs_yaw reported by the compass system lags
// the actual yaw by about 5 seconds, and also periodically realigns itself with about a 30 second period,
// which makes it very hard to be completely sure exactly where the antenna is _really_ pointing
// especially during the high speed slew. This can cause odd pointing artifacts from time to time. The best strategy is to
// position and point the mount so the aircraft does not 'go behind' the antenna (if possible)
//
// With my antenna mount, large pwm output drives the antenna anticlockise, so need:
// param set RC1_REV -1
// to reverse the servo. Yours may be different
//
// You MUST set RC1_MIN and RC1_MAX so that your servo drives the antenna azimuth from -180 to 180 relative
// to the mount.
// To drive my HS-645MG servos through their full 180 degrees of rotational range and therefore the
// antenna through a full 360 degrees, I have to set:
// param set RC1_MAX 2380
// param set RC1_MIN 680
// According to the specs at https://www.servocity.com/html/hs-645mg_ultra_torque.html,
// that should be 600 through 2400, but the azimuth gearing in my antenna pointer is not exactly 2:1
int32_t err = wrap_180_cd(ahrs_yaw_cd - yaw_cd);
/*
a positive error means that we need to rotate counter-clockwise
a negative error means that we need to rotate clockwise
Use our current yawspeed to determine if we are moving in the
right direction
*/
static int8_t slew_dir;
static uint32_t slew_start_ms;
int8_t new_slew_dir = slew_dir;
Vector3f earth_rotation = ahrs.get_gyro() * ahrs.get_dcm_matrix();
bool making_progress;
if (slew_dir != 0) {
making_progress = (-slew_dir * earth_rotation.z >= 0);
} else {
making_progress = (err * earth_rotation.z >= 0);
}
if (abs(channel_yaw.servo_out) == 18000 &&
abs(err) > margin &&
making_progress &&
hal.scheduler->millis() - slew_start_ms > g.min_reverse_time*1000) {
// we are at the limit of the servo and are not moving in the
// right direction, so slew the other way
new_slew_dir = -channel_yaw.servo_out / 18000;
slew_start_ms = hal.scheduler->millis();
}
/*
stop slewing and revert to normal control when normal control
should move us in the right direction
*/
if (slew_dir * err < -margin) {
new_slew_dir = 0;
}
if (new_slew_dir != slew_dir) {
gcs_send_text_fmt(PSTR("SLEW: %d/%d err=%ld servo=%ld ez=%.3f"),
(int)slew_dir, (int)new_slew_dir,
(long)err,
(long)channel_yaw.servo_out,
degrees(ahrs.get_gyro().z));
}
slew_dir = new_slew_dir;
int16_t new_servo_out;
if (slew_dir != 0) {
new_servo_out = slew_dir * 18000;
g.pidYaw2Srv.reset_I();
} else {
float servo_change = g.pidYaw2Srv.get_pid(err);
servo_change = constrain_float(servo_change, -18000, 18000);
new_servo_out = constrain_float(channel_yaw.servo_out - servo_change, -18000, 18000);
}
// add slew rate limit
if (g.yaw_slew_time > 0.02f) {
uint16_t max_change = 0.02f * 36000.0f / g.yaw_slew_time;
if (max_change < 1) {
max_change = 1;
}
new_servo_out = constrain_float(new_servo_out,
channel_yaw.servo_out - max_change,
channel_yaw.servo_out + max_change);
}
channel_yaw.servo_out = new_servo_out;
}
/**
update the yaw (azimuth) servo. The aim is to drive the boards ahrs
yaw to the requested yaw, so the board (and therefore the antenna)
will be pointing at the target
*/
static void update_yaw_onoff_servo(float yaw)
{
int32_t ahrs_yaw_cd = wrap_180_cd(ahrs.yaw_sensor);
int32_t yaw_cd = wrap_180_cd(yaw*100);
int32_t err_cd = wrap_180_cd(ahrs_yaw_cd - yaw_cd);
float err = err_cd * 0.01f;
float acceptable_error = g.onoff_yaw_rate * g.onoff_yaw_mintime;
if (fabsf(err) < acceptable_error) {
channel_yaw.servo_out = 0;
} else if (err > 0) {
// positive error means we are clockwise of the target, so
// move anti-clockwise
channel_yaw.servo_out = -18000;
} else {
// negative error means we are anti-clockwise of the target, so
// move clockwise
channel_yaw.servo_out = 18000;
}
}
/**
update the yaw (azimuth) servo.
*/
static void update_yaw_servo(float yaw)
{
switch ((enum ServoType)g.servo_type.get()) {
case SERVO_TYPE_ONOFF:
update_yaw_onoff_servo(yaw);
break;
case SERVO_TYPE_POSITION:
default:
update_yaw_position_servo(yaw);
break;
}
channel_yaw.calc_pwm();
channel_yaw.output();
}
/**
update_vehicle_position_estimate - updates estimate of vehicle positions
should be called at 50hz

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