ardupilot/ArduCopter/heli.pde

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/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
// Traditional helicopter variables and functions
#if FRAME_CONFIG == HELI_FRAME
#ifndef HELI_DYNAMIC_FLIGHT_SPEED_MIN
#define HELI_DYNAMIC_FLIGHT_SPEED_MIN 500 // we are in "dynamic flight" when the speed is over 1m/s for 2 seconds
#endif
// counter to control dynamic flight profile
static int8_t heli_dynamic_flight_counter;
// Tradheli flags
static struct {
uint8_t dynamic_flight : 1; // 0 // true if we are moving at a significant speed (used to turn on/off leaky I terms)
} heli_flags;
#if HELI_CC_COMP == ENABLED
static LowPassFilterFloat rate_dynamics_filter; // Rate Dynamics filter
#endif
// heli_init - perform any special initialisation required for the tradheli
static void heli_init()
{
#if HELI_CC_COMP == ENABLED
rate_dynamics_filter.set_cutoff_frequency(0.01f, 4.0f);
#endif
}
// get_pilot_desired_collective - converts pilot input (from 0 ~ 1000) to a value that can be fed into the g.rc_3.servo_out function
static int16_t get_pilot_desired_collective(int16_t control_in)
{
// return immediately if reduce collective range for manual flight has not been configured
if (g.heli_stab_col_min == 0 && g.heli_stab_col_max == 1000) {
return control_in;
}
// scale pilot input to reduced collective range
float scalar = ((float)(g.heli_stab_col_max - g.heli_stab_col_min))/1000.0f;
int16_t collective_out = g.heli_stab_col_min + control_in * scalar;
collective_out = constrain_int16(collective_out, 0, 1000);
return collective_out;
}
// heli_check_dynamic_flight - updates the dynamic_flight flag based on our horizontal velocity
// should be called at 50hz
static void check_dynamic_flight(void)
{
if (!motors.armed() || throttle_mode == THROTTLE_LAND || !motors.motor_runup_complete()) {
heli_dynamic_flight_counter = 0;
heli_flags.dynamic_flight = false;
return;
}
bool moving = false;
// with GPS lock use inertial nav to determine if we are moving
if (GPS_ok()) {
// get horizontal velocity
float velocity = inertial_nav.get_velocity_xy();
moving = (velocity >= HELI_DYNAMIC_FLIGHT_SPEED_MIN);
}else{
// with no GPS lock base it on throttle and forward lean angle
moving = (g.rc_3.servo_out > 800 || ahrs.pitch_sensor < -1500);
}
if (moving) {
// if moving for 2 seconds, set the dynamic flight flag
if (!heli_flags.dynamic_flight) {
heli_dynamic_flight_counter++;
if (heli_dynamic_flight_counter >= 100) {
heli_flags.dynamic_flight = true;
heli_dynamic_flight_counter = 100;
}
}
}else{
// if not moving for 2 seconds, clear the dynamic flight flag
if (heli_flags.dynamic_flight) {
if (heli_dynamic_flight_counter > 0) {
heli_dynamic_flight_counter--;
}else{
heli_flags.dynamic_flight = false;
}
}
}
}
// heli_integrated_swash_controller - convert desired roll and pitch rate to roll and pitch swash angles
// should be called at 100hz
// output placed directly into g.rc_1.servo_out and g.rc_2.servo_out
static void heli_integrated_swash_controller(int32_t target_roll_rate, int32_t target_pitch_rate)
{
int32_t roll_p, roll_i, roll_d, roll_ff; // used to capture pid values for logging
int32_t pitch_p, pitch_i, pitch_d, pitch_ff;
int32_t current_roll_rate, current_pitch_rate; // this iteration's rate
int32_t roll_rate_error, pitch_rate_error; // simply target_rate - current_rate
int32_t roll_output, pitch_output; // output from pid controller
static bool roll_pid_saturated, pitch_pid_saturated; // tracker from last loop if the PID was saturated
current_roll_rate = (omega.x * DEGX100); // get current roll rate
current_pitch_rate = (omega.y * DEGX100); // get current pitch rate
roll_rate_error = target_roll_rate - current_roll_rate;
pitch_rate_error = target_pitch_rate - current_pitch_rate;
roll_p = g.pid_rate_roll.get_p(roll_rate_error);
pitch_p = g.pid_rate_pitch.get_p(pitch_rate_error);
if (roll_pid_saturated){
roll_i = g.pid_rate_roll.get_integrator(); // Locked Integrator due to PID saturation on previous cycle
} else {
if (motors.has_flybar()) { // Mechanical Flybars get regular integral for rate auto trim
if (target_roll_rate > -50 && target_roll_rate < 50){ // Frozen at high rates
roll_i = g.pid_rate_roll.get_i(roll_rate_error, G_Dt);
} else {
roll_i = g.pid_rate_roll.get_integrator();
}
} else {
if (heli_flags.dynamic_flight){
roll_i = g.pid_rate_roll.get_i(roll_rate_error, G_Dt);
} else {
roll_i = g.pid_rate_roll.get_leaky_i(roll_rate_error, G_Dt, RATE_INTEGRATOR_LEAK_RATE);
}
}
}
if (pitch_pid_saturated){
pitch_i = g.pid_rate_pitch.get_integrator(); // Locked Integrator due to PID saturation on previous cycle
} else {
if (motors.has_flybar()) { // Mechanical Flybars get regular integral for rate auto trim
if (target_pitch_rate > -50 && target_pitch_rate < 50){ // Frozen at high rates
pitch_i = g.pid_rate_pitch.get_i(pitch_rate_error, G_Dt);
} else {
pitch_i = g.pid_rate_pitch.get_integrator();
}
} else {
if (heli_flags.dynamic_flight){
pitch_i = g.pid_rate_pitch.get_i(pitch_rate_error, G_Dt);
} else {
pitch_i = g.pid_rate_pitch.get_leaky_i(pitch_rate_error, G_Dt, RATE_INTEGRATOR_LEAK_RATE);
}
}
}
roll_d = g.pid_rate_roll.get_d(target_roll_rate, G_Dt);
pitch_d = g.pid_rate_pitch.get_d(target_pitch_rate, G_Dt);
roll_ff = g.heli_roll_ff * target_roll_rate;
pitch_ff = g.heli_pitch_ff * target_pitch_rate;
roll_output = roll_p + roll_i + roll_d + roll_ff;
pitch_output = pitch_p + pitch_i + pitch_d + pitch_ff;
#if HELI_CC_COMP == ENABLED
// Do cross-coupling compensation for low rpm helis
// Credit: Jolyon Saunders
// Note: This is not widely tested at this time. Will not be used by default yet.
float cc_axis_ratio = 2.0f; // Ratio of compensation on pitch vs roll axes. Number >1 means pitch is affected more than roll
float cc_kp = 0.0002f; // Compensation p term. Setting this to zero gives h_phang only, while increasing it will increase the p term of correction
float cc_kd = 0.127f; // Compensation d term, scaled. This accounts for flexing of the blades, dampers etc. Originally was (motors.ext_gyro_gain * 0.0001)
float cc_angle, cc_total_output;
uint32_t cc_roll_d, cc_pitch_d, cc_sum_d;
int32_t cc_scaled_roll;
int32_t cc_roll_output; // Used to temporarily hold output while rotation is being calculated
int32_t cc_pitch_output; // Used to temporarily hold output while rotation is being calculated
static int32_t last_roll_output = 0;
static int32_t last_pitch_output = 0;
cc_scaled_roll = roll_output / cc_axis_ratio; // apply axis ratio to roll
cc_total_output = safe_sqrt(cc_scaled_roll * cc_scaled_roll + pitch_output * pitch_output) * cc_kp;
// find the delta component
cc_roll_d = (roll_output - last_roll_output) / cc_axis_ratio;
cc_pitch_d = pitch_output - last_pitch_output;
cc_sum_d = safe_sqrt(cc_roll_d * cc_roll_d + cc_pitch_d * cc_pitch_d);
// do the magic.
cc_angle = cc_kd * cc_sum_d * cc_total_output - cc_total_output * motors.get_phase_angle();
// smooth angle variations, apply constraints
cc_angle = rate_dynamics_filter.apply(cc_angle);
cc_angle = constrain_float(cc_angle, -90.0f, 0.0f);
cc_angle = radians(cc_angle);
// Make swash rate vector
Vector2f swashratevector;
swashratevector.x = cosf(cc_angle);
swashratevector.y = sinf(cc_angle);
swashratevector.normalize();
// rotate the output
cc_roll_output = roll_output;
cc_pitch_output = pitch_output;
roll_output = - (cc_pitch_output * swashratevector.y - cc_roll_output * swashratevector.x);
pitch_output = cc_pitch_output * swashratevector.x + cc_roll_output * swashratevector.y;
// make current outputs old, for next iteration
last_roll_output = cc_roll_output;
last_pitch_output = cc_pitch_output;
# endif // HELI_CC_COMP
#if HELI_PIRO_COMP == ENABLED
if (control_mode <= ACRO){
int32_t piro_roll_i, piro_pitch_i; // used to hold i term while doing prio comp
piro_roll_i = roll_i;
piro_pitch_i = pitch_i;
Vector2f yawratevector;
yawratevector.x = cos(-omega.z/100);
yawratevector.y = sin(-omega.z/100);
yawratevector.normalize();
roll_i = piro_roll_i * yawratevector.x - piro_pitch_i * yawratevector.y;
pitch_i = piro_pitch_i * yawratevector.x + piro_roll_i * yawratevector.y;
g.pid_rate_pitch.set_integrator(pitch_i);
g.pid_rate_roll.set_integrator(roll_i);
}
#endif //HELI_PIRO_COMP
if (labs(roll_output) > 4500){
roll_output = constrain_int32(roll_output, -4500, 4500); // constrain output
roll_pid_saturated = true; // freeze integrator next cycle
} else {
roll_pid_saturated = false; // unfreeze integrator
}
if (labs(pitch_output) > 4500){
pitch_output = constrain_int32(pitch_output, -4500, 4500); // constrain output
pitch_pid_saturated = true; // freeze integrator next cycle
} else {
pitch_pid_saturated = false; // unfreeze integrator
}
g.rc_1.servo_out = roll_output;
g.rc_2.servo_out = pitch_output;
}
static int16_t
get_heli_rate_yaw(int32_t target_rate)
{
int32_t p,i,d,ff; // used to capture pid values for logging
int32_t current_rate; // this iteration's rate
int32_t rate_error;
int32_t output;
static bool pid_saturated; // tracker from last loop if the PID was saturated
current_rate = (omega.z * DEGX100); // get current rate
// rate control
rate_error = target_rate - current_rate;
// separately calculate p, i, d values for logging
p = g.pid_rate_yaw.get_p(rate_error);
if (pid_saturated){
i = g.pid_rate_yaw.get_integrator(); // Locked Integrator due to PID saturation on previous cycle
} else {
if (motors.motor_runup_complete()){
i = g.pid_rate_yaw.get_i(rate_error, G_Dt);
} else {
i = g.pid_rate_yaw.get_leaky_i(rate_error, G_Dt, RATE_INTEGRATOR_LEAK_RATE); // If motor is not running use leaky I-term to avoid excessive build-up
}
}
d = g.pid_rate_yaw.get_d(rate_error, G_Dt);
ff = g.heli_yaw_ff*target_rate;
output = p + i + d + ff;
if (labs(output) > 4500){
output = constrain_int32(output, -4500, 4500); // constrain output
pid_saturated = true; // freeze integrator next cycle
} else {
pid_saturated = false; // unfreeze integrator
}
#if LOGGING_ENABLED == ENABLED
// log output if PID loggins is on and we are tuning the yaw
if( g.log_bitmask & MASK_LOG_PID && (g.radio_tuning == CH6_YAW_RATE_KP || g.radio_tuning == CH6_YAW_RATE_KD) ) {
pid_log_counter++;
if( pid_log_counter >= 10 ) { // (update rate / desired output rate) = (100hz / 10hz) = 10
pid_log_counter = 0;
Log_Write_PID(CH6_YAW_RATE_KP, rate_error, p, i, d, output, tuning_value);
}
}
#endif
return output; // output control
}
// heli_update_landing_swash - sets swash plate flag so higher minimum is used when landed or landing
// should be called soon after update_land_detector in main code
static void heli_update_landing_swash()
{
switch(throttle_mode) {
case THROTTLE_MANUAL:
case THROTTLE_MANUAL_TILT_COMPENSATED:
case THROTTLE_MANUAL_HELI:
// manual modes always uses full swash range
motors.set_collective_for_landing(false);
break;
case THROTTLE_LAND:
// landing always uses limit swash range
motors.set_collective_for_landing(true);
break;
case THROTTLE_HOLD:
case THROTTLE_AUTO:
default:
// auto and hold use limited swash when landed
motors.set_collective_for_landing(ap.land_complete || !ap.auto_armed);
break;
}
}
// heli_update_rotor_speed_targets - reads pilot input and passes new rotor speed targets to heli motors object
static void heli_update_rotor_speed_targets()
{
// get rotor control method
uint8_t rsc_control_mode = motors.get_rsc_mode();
switch (rsc_control_mode) {
case AP_MOTORS_HELI_RSC_MODE_NONE:
// even though pilot passes rotors speed directly to rotor ESC via receiver, motor lib needs to know if
// rotor is spinning in case we are using direct drive tailrotor which must be spun up at same time
case AP_MOTORS_HELI_RSC_MODE_CH8_PASSTHROUGH:
// pass through pilot desired rotor speed
motors.set_desired_rotor_speed(g.rc_8.control_in);
break;
case AP_MOTORS_HELI_RSC_MODE_SETPOINT:
// pass setpoint through as desired rotor speed
if (g.rc_8.control_in > 0) {
motors.set_desired_rotor_speed(motors.get_rsc_setpoint());
}else{
motors.set_desired_rotor_speed(0);
}
break;
}
}
#endif // FRAME_CONFIG == HELI_FRAME