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AR_AttitudeControl: caller provides dt instead of calculated internally

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This allows the vehicle's main loop rate to be used instead of an internally calculated dt which suffers from jitter
This commit is contained in:
Randy Mackay 2018-05-22 10:04:53 +09:00
parent c032095c80
commit a7fbfe7767
2 changed files with 42 additions and 39 deletions
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65
libraries/APM_Control/AR_AttitudeControl.cpp
View File

@ -182,7 +182,7 @@ AR_AttitudeControl::AR_AttitudeControl(AP_AHRS &ahrs) :
// return a steering servo output from -1.0 to +1.0 given a desired lateral acceleration rate in m/s/s.
// positive lateral acceleration is to the right.
float AR_AttitudeControl::get_steering_out_lat_accel(float desired_accel, bool motor_limit_left, bool motor_limit_right)
float AR_AttitudeControl::get_steering_out_lat_accel(float desired_accel, bool motor_limit_left, bool motor_limit_right, float dt)
{
// record desired accel for reporting purposes
_steer_lat_accel_last_ms = AP_HAL::millis();
@ -208,11 +208,11 @@ float AR_AttitudeControl::get_steering_out_lat_accel(float desired_accel, bool m
// Calculate the desired steering rate given desired_accel and speed
const float desired_rate = desired_accel / speed;
return get_steering_out_rate(desired_rate, motor_limit_left, motor_limit_right);
return get_steering_out_rate(desired_rate, motor_limit_left, motor_limit_right, dt);
}
// return a steering servo output from -1 to +1 given a heading in radians
float AR_AttitudeControl::get_steering_out_heading(float heading_rad, float rate_max, bool motor_limit_left, bool motor_limit_right)
float AR_AttitudeControl::get_steering_out_heading(float heading_rad, float rate_max, bool motor_limit_left, bool motor_limit_right, float dt)
{
// calculate heading error (in radians)
const float yaw_error = wrap_PI(heading_rad - _ahrs.yaw);
@ -224,29 +224,27 @@ float AR_AttitudeControl::get_steering_out_heading(float heading_rad, float rate
desired_rate = constrain_float(desired_rate, -rate_max, rate_max);
}
return get_steering_out_rate(desired_rate, motor_limit_left, motor_limit_right);
return get_steering_out_rate(desired_rate, motor_limit_left, motor_limit_right, dt);
}
// return a steering servo output from -1 to +1 given a
// desired yaw rate in radians/sec. Positive yaw is to the right.
float AR_AttitudeControl::get_steering_out_rate(float desired_rate, bool motor_limit_left, bool motor_limit_right)
float AR_AttitudeControl::get_steering_out_rate(float desired_rate, bool motor_limit_left, bool motor_limit_right, float dt)
{
// calculate dt
// sanity check dt
dt = constrain_float(dt, 0.0f, 1.0f);
// if not called recently, reset input filter and desired turn rate to actual turn rate (used for accel limiting)
const uint32_t now = AP_HAL::millis();
float dt = (now - _steer_turn_last_ms) / 1000.0f;
if ((_steer_turn_last_ms == 0) || (dt > (AR_ATTCONTROL_TIMEOUT_MS / 1000.0f))) {
dt = 0.0f;
if ((_steer_turn_last_ms == 0) || ((now - _steer_turn_last_ms) > AR_ATTCONTROL_TIMEOUT_MS)) {
_steer_rate_pid.reset_filter();
// reset desired turn rate to actual turn rate for accel limiting
_desired_turn_rate = _ahrs.get_yaw_rate_earth();
} else {
_steer_rate_pid.set_dt(dt);
}
_steer_turn_last_ms = now;
// acceleration limit desired turn rate
if (is_positive(_steer_accel_max)) {
const float change_max = radians(_steer_accel_max) * dt;
if (is_positive(dt) && is_positive(change_max)) {
desired_rate = constrain_float(desired_rate, _desired_turn_rate - change_max, _desired_turn_rate + change_max);
}
_desired_turn_rate = desired_rate;
@ -261,6 +259,9 @@ float AR_AttitudeControl::get_steering_out_rate(float desired_rate, bool motor_l
// We do this in earth frame to allow for rover leaning over in hard corners
const float rate_error = (_desired_turn_rate - _ahrs.get_yaw_rate_earth());
// set PID's dt
_steer_rate_pid.set_dt(dt);
// record desired rate for logging purposes only
_steer_rate_pid.set_desired_rate(_desired_turn_rate);
@ -320,8 +321,11 @@ bool AR_AttitudeControl::get_lat_accel(float &lat_accel) const
// return a throttle output from -1 to +1 given a desired speed in m/s (use negative speeds to travel backwards)
// motor_limit should be true if motors have hit their upper or lower limits
// cruise speed should be in m/s, cruise throttle should be a number from -1 to +1
float AR_AttitudeControl::get_throttle_out_speed(float desired_speed, bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle)
float AR_AttitudeControl::get_throttle_out_speed(float desired_speed, bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle, float dt)
{
// sanity check dt
dt = constrain_float(dt, 0.0f, 1.0f);
// get speed forward
float speed;
if (!get_forward_speed(speed)) {
@ -330,19 +334,19 @@ float AR_AttitudeControl::get_throttle_out_speed(float desired_speed, bool motor
return 0.0f;
}
// calculate dt
// if not called recently, reset input filter and desired speed to actual speed (used for accel limiting)
const uint32_t now = AP_HAL::millis();
float dt = (now - _speed_last_ms) / 1000.0f;
if ((_speed_last_ms == 0) || (dt > (AR_ATTCONTROL_TIMEOUT_MS / 1000.0f))) {
dt = 0.0f;
if ((_speed_last_ms == 0) || ((now - _speed_last_ms) > AR_ATTCONTROL_TIMEOUT_MS)) {
_throttle_speed_pid.reset_filter();
} else {
_throttle_speed_pid.set_dt(dt);
_desired_speed = speed;
}
_speed_last_ms = now;
// record desired speed for next iteration
_desired_speed = desired_speed;
// acceleration limit desired speed
_desired_speed = get_desired_speed_accel_limited(desired_speed, dt);
// set PID's dt
_throttle_speed_pid.set_dt(dt);
// calculate speed error and pass to PID controller
const float speed_error = desired_speed - speed;
@ -397,7 +401,7 @@ float AR_AttitudeControl::get_throttle_out_speed(float desired_speed, bool motor
}
// return a throttle output from -1 to +1 to perform a controlled stop. returns true once the vehicle has stopped
float AR_AttitudeControl::get_throttle_out_stop(bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle, bool &stopped)
float AR_AttitudeControl::get_throttle_out_stop(bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle, float dt, bool &stopped)
{
// get current system time
const uint32_t now = AP_HAL::millis();
@ -406,7 +410,7 @@ float AR_AttitudeControl::get_throttle_out_stop(bool motor_limit_low, bool motor
bool _stopped = (_stop_last_ms != 0) && (now - _stop_last_ms) < 300;
// get deceleration limited speed
float desired_speed_limited = get_desired_speed_accel_limited(0.0f);
float desired_speed_limited = get_desired_speed_accel_limited(0.0f, dt);
// get speed forward
float speed;
@ -432,7 +436,7 @@ float AR_AttitudeControl::get_throttle_out_stop(bool motor_limit_low, bool motor
// clear stopped system time
_stop_last_ms = 0;
// run speed controller to bring vehicle to stop
return get_throttle_out_speed(desired_speed_limited, motor_limit_low, motor_limit_high, cruise_speed, cruise_throttle);
return get_throttle_out_speed(desired_speed_limited, motor_limit_low, motor_limit_high, cruise_speed, cruise_throttle, dt);
}
}
@ -478,18 +482,17 @@ float AR_AttitudeControl::get_desired_speed() const
}
// get acceleration limited desired speed
float AR_AttitudeControl::get_desired_speed_accel_limited(float desired_speed) const
float AR_AttitudeControl::get_desired_speed_accel_limited(float desired_speed, float dt) const
{
// calculate dt
const uint32_t now = AP_HAL::millis();
float dt = (now - _speed_last_ms) / 1000.0f;
// sanity check dt
dt = constrain_float(dt, 0.0f, 1.0f);
// use previous desired speed as basis for accel limiting
float speed_prev = _desired_speed;
// if no recent calls to speed controller limit based on current speed
if (is_negative(dt) || (dt > AR_ATTCONTROL_TIMEOUT_MS / 1000.0f)) {
dt = 0.0f;
const uint32_t now = AP_HAL::millis();
if ((_speed_last_ms == 0) || ((now - _speed_last_ms) > AR_ATTCONTROL_TIMEOUT_MS)) {
get_forward_speed(speed_prev);
}

14
libraries/APM_Control/AR_AttitudeControl.h
View File

@ -44,15 +44,15 @@ public:
//
// return a steering servo output from -1.0 to +1.0 given a desired lateral acceleration rate in m/s/s.
// positive lateral acceleration is to the right.
float get_steering_out_lat_accel(float desired_accel, bool motor_limit_left, bool motor_limit_right);
// positive lateral acceleration is to the right. dt should normally be the main loop rate.
float get_steering_out_lat_accel(float desired_accel, bool motor_limit_left, bool motor_limit_right, float dt);
// return a steering servo output from -1 to +1 given a heading in radians
float get_steering_out_heading(float heading_rad, float rate_max, bool motor_limit_left, bool motor_limit_right);
float get_steering_out_heading(float heading_rad, float rate_max, bool motor_limit_left, bool motor_limit_right, float dt);
// return a steering servo output from -1 to +1 given a
// desired yaw rate in radians/sec. Positive yaw is to the right.
float get_steering_out_rate(float desired_rate, bool motor_limit_left, bool motor_limit_right);
float get_steering_out_rate(float desired_rate, bool motor_limit_left, bool motor_limit_right, float dt);
// get latest desired turn rate in rad/sec recorded during calls to get_steering_out_rate. For reporting purposes only
float get_desired_turn_rate() const;
@ -76,10 +76,10 @@ public:
// desired_speed argument should already have been passed through get_desired_speed_accel_limited function
// motor_limit should be true if motors have hit their upper or lower limits
// cruise speed should be in m/s, cruise throttle should be a number from -1 to +1
float get_throttle_out_speed(float desired_speed, bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle);
float get_throttle_out_speed(float desired_speed, bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle, float dt);
// return a throttle output from -1 to +1 to perform a controlled stop. stopped is set to true once stop has been completed
float get_throttle_out_stop(bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle, bool &stopped);
float get_throttle_out_stop(bool motor_limit_low, bool motor_limit_high, float cruise_speed, float cruise_throttle, float dt, bool &stopped);
// low level control accessors for reporting and logging
AC_P& get_steering_angle_p() { return _steer_angle_p; }
@ -99,7 +99,7 @@ public:
float get_desired_speed() const;
// get acceleration limited desired speed
float get_desired_speed_accel_limited(float desired_speed) const;
float get_desired_speed_accel_limited(float desired_speed, float dt) const;
// get minimum stopping distance (in meters) given a speed (in m/s)
float get_stopping_distance(float speed);