stabilization_attitude_euler_int.c

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/*
 * Copyright (C) 2008-2009 Antoine Drouin <poinix@gmail.com>
 *
 * This file is part of paparazzi.
 *
 * paparazzi is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * paparazzi is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with paparazzi; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
#include "std.h"
#include "generated/airframe.h"
 
#include "firmwares/rotorcraft/stabilization/stabilization_attitude_euler_int.h"
#include "firmwares/rotorcraft/stabilization/stabilization_attitude_ref_euler_int.h"
#include "paparazzi.h"
#include "state.h"
 
#ifndef USE_ATTITUDE_REF
#define USE_ATTITUDE_REF 1
#endif
 
#ifndef STABILIZATION_ATTITUDE_PHI_FFDGAIN
#define STABILIZATION_ATTITUDE_PHI_FFDGAIN 0
#endif
#ifndef STABILIZATION_ATTITUDE_THETA_FFDGAIN
#define STABILIZATION_ATTITUDE_THETA_FFDGAIN 0
#endif
#ifndef STABILIZATION_ATTITUDE_PSI_FFDGAIN
#define STABILIZATION_ATTITUDE_PSI_FFDGAIN 0
#endif
 
struct Int32AttitudeGains  stabilization_gains;
 
/* warn if some gains are still negative */
#if (STABILIZATION_ATTITUDE_PHI_PGAIN < 0) || \
  (STABILIZATION_ATTITUDE_THETA_PGAIN < 0) || \
  (STABILIZATION_ATTITUDE_PSI_PGAIN < 0)   || \
  (STABILIZATION_ATTITUDE_PHI_DGAIN < 0)   || \
  (STABILIZATION_ATTITUDE_THETA_DGAIN < 0) || \
  (STABILIZATION_ATTITUDE_PSI_DGAIN < 0)   || \
  (STABILIZATION_ATTITUDE_PHI_IGAIN < 0)   || \
  (STABILIZATION_ATTITUDE_THETA_IGAIN < 0) || \
  (STABILIZATION_ATTITUDE_PSI_IGAIN  < 0)
#error "ALL control gains have to be positive!!!"
#endif
 
struct Int32Eulers stabilization_att_sum_err;
 
int32_t stabilization_att_fb_cmd[COMMANDS_NB];
int32_t stabilization_att_ff_cmd[COMMANDS_NB];
 
static struct Int32Eulers stab_att_sp_euler;
static struct AttRefEulerInt att_ref_euler_i;
 
static inline void reset_psi_ref_from_body(void)
{
  //sp has been set from body using stabilization_attitude_get_yaw_i, use that value
  att_ref_euler_i.euler.psi = stateGetNedToBodyEulers_i()->psi << (REF_ANGLE_FRAC - INT32_ANGLE_FRAC);
  att_ref_euler_i.rate.r = 0;
  att_ref_euler_i.accel.r = 0;
}
 
#if PERIODIC_TELEMETRY
#include "modules/datalink/telemetry.h"
 
static void send_att(struct transport_tx *trans, struct link_device *dev)
{
  struct Int32Rates *body_rate = stateGetBodyRates_i();
  struct Int32Eulers *att = stateGetNedToBodyEulers_i();
  pprz_msg_send_STAB_ATTITUDE_INT(trans, dev, AC_ID,
                                  &(body_rate->p), &(body_rate->q), &(body_rate->r),
                                  &(att->phi), &(att->theta), &(att->psi),
                                  &stab_att_sp_euler.phi,
                                  &stab_att_sp_euler.theta,
                                  &stab_att_sp_euler.psi,
                                  &stabilization_att_sum_err.phi,
                                  &stabilization_att_sum_err.theta,
                                  &stabilization_att_sum_err.psi,
                                  &stabilization_att_fb_cmd[COMMAND_ROLL],
                                  &stabilization_att_fb_cmd[COMMAND_PITCH],
                                  &stabilization_att_fb_cmd[COMMAND_YAW],
                                  &stabilization_att_ff_cmd[COMMAND_ROLL],
                                  &stabilization_att_ff_cmd[COMMAND_PITCH],
                                  &stabilization_att_ff_cmd[COMMAND_YAW],
                                  &stabilization.cmd[COMMAND_ROLL],
                                  &stabilization.cmd[COMMAND_PITCH],
                                  &stabilization.cmd[COMMAND_YAW]);
}
 
static void send_att_ref(struct transport_tx *trans, struct link_device *dev)
{
  pprz_msg_send_STAB_ATTITUDE_REF_INT(trans, dev, AC_ID,
                                      &stab_att_sp_euler.phi,
                                      &stab_att_sp_euler.theta,
                                      &stab_att_sp_euler.psi,
                                      &att_ref_euler_i.euler.phi,
                                      &att_ref_euler_i.euler.theta,
                                      &att_ref_euler_i.euler.psi,
                                      &att_ref_euler_i.rate.p,
                                      &att_ref_euler_i.rate.q,
                                      &att_ref_euler_i.rate.r,
                                      &att_ref_euler_i.accel.p,
                                      &att_ref_euler_i.accel.q,
                                      &att_ref_euler_i.accel.r);
}
#endif
 
void stabilization_attitude_euler_int_init(void)
{
 
  INT_EULERS_ZERO(stab_att_sp_euler);
 
  attitude_ref_euler_int_init(&att_ref_euler_i);
 
 
  VECT3_ASSIGN(stabilization_gains.p,
               STABILIZATION_ATTITUDE_PHI_PGAIN,
               STABILIZATION_ATTITUDE_THETA_PGAIN,
               STABILIZATION_ATTITUDE_PSI_PGAIN);
 
  VECT3_ASSIGN(stabilization_gains.d,
               STABILIZATION_ATTITUDE_PHI_DGAIN,
               STABILIZATION_ATTITUDE_THETA_DGAIN,
               STABILIZATION_ATTITUDE_PSI_DGAIN);
 
  VECT3_ASSIGN(stabilization_gains.i,
               STABILIZATION_ATTITUDE_PHI_IGAIN,
               STABILIZATION_ATTITUDE_THETA_IGAIN,
               STABILIZATION_ATTITUDE_PSI_IGAIN);
 
  VECT3_ASSIGN(stabilization_gains.dd,
               STABILIZATION_ATTITUDE_PHI_DDGAIN,
               STABILIZATION_ATTITUDE_THETA_DDGAIN,
               STABILIZATION_ATTITUDE_PSI_DDGAIN);
 
  VECT3_ASSIGN(stabilization_gains.ffd,
               STABILIZATION_ATTITUDE_PHI_FFDGAIN,
               STABILIZATION_ATTITUDE_THETA_FFDGAIN,
               STABILIZATION_ATTITUDE_PSI_FFDGAIN);
 
  INT_EULERS_ZERO(stabilization_att_sum_err);
 
#if PERIODIC_TELEMETRY
  register_periodic_telemetry(DefaultPeriodic, PPRZ_MSG_ID_STAB_ATTITUDE_INT, send_att);
  register_periodic_telemetry(DefaultPeriodic, PPRZ_MSG_ID_STAB_ATTITUDE_REF_INT, send_att_ref);
#endif
}
 
void stabilization_attitude_enter(void)
{
  reset_psi_ref_from_body();
  INT_EULERS_ZERO(stabilization_att_sum_err);
}
 
#define OFFSET_AND_ROUND(_a, _b) (((_a)+(1<<((_b)-1)))>>(_b))
#define OFFSET_AND_ROUND2(_a, _b) (((_a)+(1<<((_b)-1))-((_a)<0?1:0))>>(_b))
 
#define MAX_SUM_ERR 4000000
 
void stabilization_attitude_run(bool in_flight, struct StabilizationSetpoint *sp, struct ThrustSetpoint *thrust, int32_t *cmd)
{
  stab_att_sp_euler = stab_sp_to_eulers_i(sp);
 
  /* update reference */
#if USE_ATTITUDE_REF
  attitude_ref_euler_int_update(&att_ref_euler_i, &stab_att_sp_euler);
#else
  INT32_EULERS_LSHIFT(att_ref_euler_i.euler, stab_att_sp_euler, (REF_ANGLE_FRAC - INT32_ANGLE_FRAC));
  INT_RATES_ZERO(att_ref_euler_i.rate);
  INT_RATES_ZERO(att_ref_euler_i.accel);
#endif
 
  const struct Int32Eulers att_ref_scaled = {
      OFFSET_AND_ROUND(att_ref_euler_i.euler.phi, (REF_ANGLE_FRAC - INT32_ANGLE_FRAC)),
      OFFSET_AND_ROUND(att_ref_euler_i.euler.theta, (REF_ANGLE_FRAC - INT32_ANGLE_FRAC)),
      OFFSET_AND_ROUND(att_ref_euler_i.euler.psi, (REF_ANGLE_FRAC - INT32_ANGLE_FRAC))
    };
  const struct Int32Rates rate_ref_scaled = {
      OFFSET_AND_ROUND(att_ref_euler_i.rate.p, (REF_RATE_FRAC - INT32_RATE_FRAC)),
      OFFSET_AND_ROUND(att_ref_euler_i.rate.q, (REF_RATE_FRAC - INT32_RATE_FRAC)),
      OFFSET_AND_ROUND(att_ref_euler_i.rate.r, (REF_RATE_FRAC - INT32_RATE_FRAC))
    };
 
  /* compute feedforward command */
  stabilization_att_ff_cmd[COMMAND_ROLL] =
    OFFSET_AND_ROUND(stabilization_gains.dd.x * att_ref_euler_i.accel.p, 5) +
    stabilization_gains.ffd.x * rate_ref_scaled.p;
  stabilization_att_ff_cmd[COMMAND_PITCH] =
    OFFSET_AND_ROUND(stabilization_gains.dd.y * att_ref_euler_i.accel.q, 5) +
    stabilization_gains.ffd.y * rate_ref_scaled.q;
  stabilization_att_ff_cmd[COMMAND_YAW] =
    OFFSET_AND_ROUND(stabilization_gains.dd.z * att_ref_euler_i.accel.r, 5) +
    stabilization_gains.ffd.z * rate_ref_scaled.r;
 
  /* with FFD gain of 100, reference rate of 180deg/s (3.14 rad/s)
   * INT32_RATE_FRAC = 12, CMD_SHIFT = 11
   * fb cmd: 100 * 3.14 * 2^INT32_RATE_FRAC / 2^CMD_SHIFT = 628
   * max possible command is 9600
   */
 
  /* compute feedback command */
  /* attitude error            */
  struct Int32Eulers att_err;
  struct Int32Eulers *ltp_to_body_euler = stateGetNedToBodyEulers_i();
  EULERS_DIFF(att_err, att_ref_scaled, (*ltp_to_body_euler));
  INT32_ANGLE_NORMALIZE(att_err.psi);
 
  if (in_flight) {
    /* update integrator */
    EULERS_ADD(stabilization_att_sum_err, att_err);
    EULERS_BOUND_CUBE(stabilization_att_sum_err, -MAX_SUM_ERR, MAX_SUM_ERR);
  } else {
    INT_EULERS_ZERO(stabilization_att_sum_err);
  }
 
  /* rate error                */
  struct Int32Rates rate_err;
  struct Int32Rates *body_rate = stateGetBodyRates_i();
  RATES_DIFF(rate_err, rate_ref_scaled, (*body_rate));
 
  /* PID                  */
  stabilization_att_fb_cmd[COMMAND_ROLL] =
    stabilization_gains.p.x    * att_err.phi +
    stabilization_gains.d.x    * rate_err.p +
    OFFSET_AND_ROUND2((stabilization_gains.i.x  * stabilization_att_sum_err.phi), 10);
 
  stabilization_att_fb_cmd[COMMAND_PITCH] =
    stabilization_gains.p.y    * att_err.theta +
    stabilization_gains.d.y    * rate_err.q +
    OFFSET_AND_ROUND2((stabilization_gains.i.y  * stabilization_att_sum_err.theta), 10);
 
  stabilization_att_fb_cmd[COMMAND_YAW] =
    stabilization_gains.p.z    * att_err.psi +
    stabilization_gains.d.z    * rate_err.r +
    OFFSET_AND_ROUND2((stabilization_gains.i.z  * stabilization_att_sum_err.psi), 10);
 
 
  /* with P gain of 100, att_err of 180deg (3.14 rad)
   * fb cmd: 100 * 3.14 * 2^12 / 2^CMD_SHIFT = 628
   * max possible command is 9600
   */
#define CMD_SHIFT 11
 
  /* sum feedforward and feedback */
  cmd[COMMAND_ROLL] =
    OFFSET_AND_ROUND((stabilization_att_fb_cmd[COMMAND_ROLL] + stabilization_att_ff_cmd[COMMAND_ROLL]), CMD_SHIFT);
 
  cmd[COMMAND_PITCH] =
    OFFSET_AND_ROUND((stabilization_att_fb_cmd[COMMAND_PITCH] + stabilization_att_ff_cmd[COMMAND_PITCH]), CMD_SHIFT);
 
  cmd[COMMAND_YAW] =
    OFFSET_AND_ROUND((stabilization_att_fb_cmd[COMMAND_YAW] + stabilization_att_ff_cmd[COMMAND_YAW]), CMD_SHIFT);
 
  cmd[COMMAND_THRUST] = th_sp_to_thrust_i(thrust, 0, THRUST_AXIS_Z);
 
  /* bound the result */
  BoundAbs(cmd[COMMAND_ROLL], MAX_PPRZ);
  BoundAbs(cmd[COMMAND_PITCH], MAX_PPRZ);
  BoundAbs(cmd[COMMAND_YAW], MAX_PPRZ);
  BoundAbs(cmd[COMMAND_THRUST], MAX_PPRZ);
 
}