y2014/control_loops/shooter/shooter.cc

#include "y2014/control_loops/shooter/shooter.h"

#include <algorithm>
#include <chrono>
#include <cstdio>
#include <limits>

#include "aos/logging/logging.h"
#include "y2014/constants.h"
#include "y2014/control_loops/shooter/shooter_motor_plant.h"

namespace y2014::control_loops::shooter {

namespace chrono = ::std::chrono;
using ::aos::monotonic_clock;

using ::y2014::control_loops::shooter::kDt;
using ::y2014::control_loops::shooter::kMaxExtension;
using ::y2014::control_loops::shooter::kSpringConstant;
using ::y2014::control_loops::shooter::MakeShooterLoop;

void ZeroedStateFeedbackLoop::CapU() {
  const double old_voltage = voltage_;
  voltage_ += U(0, 0);

  uncapped_voltage_ = voltage_;

  // Make sure that reality and the observer can't get too far off.  There is a
  // delay by one cycle between the applied voltage and X_hat(2, 0), so compare
  // against last cycle's voltage.
  if (X_hat(2, 0) > last_voltage_ + 4.0) {
    voltage_ -= X_hat(2, 0) - (last_voltage_ + 4.0);
    AOS_LOG(DEBUG, "Capping due to runaway\n");
  } else if (X_hat(2, 0) < last_voltage_ - 4.0) {
    voltage_ += X_hat(2, 0) - (last_voltage_ - 4.0);
    AOS_LOG(DEBUG, "Capping due to runaway\n");
  }

  voltage_ = std::min(max_voltage_, voltage_);
  voltage_ = std::max(-max_voltage_, voltage_);
  mutable_U(0, 0) = voltage_ - old_voltage;

  last_voltage_ = voltage_;
  capped_goal_ = false;
}

void ZeroedStateFeedbackLoop::CapGoal() {
  if (uncapped_voltage() > max_voltage_) {
    double dx;
    if (index() == 0) {
      dx = (uncapped_voltage() - max_voltage_) /
           (controller().K(0, 0) -
            plant().A(1, 0) * controller().K(0, 2) / plant().A(1, 2));
      mutable_R(0, 0) -= dx;
      mutable_R(2, 0) -= -plant().A(1, 0) / plant().A(1, 2) * dx;
    } else {
      dx = (uncapped_voltage() - max_voltage_) / controller().K(0, 0);
      mutable_R(0, 0) -= dx;
    }
    capped_goal_ = true;
  } else if (uncapped_voltage() < -max_voltage_) {
    double dx;
    if (index() == 0) {
      dx = (uncapped_voltage() + max_voltage_) /
           (controller().K(0, 0) -
            plant().A(1, 0) * controller().K(0, 2) / plant().A(1, 2));
      mutable_R(0, 0) -= dx;
      mutable_R(2, 0) -= -plant().A(1, 0) / plant().A(1, 2) * dx;
    } else {
      dx = (uncapped_voltage() + max_voltage_) / controller().K(0, 0);
      mutable_R(0, 0) -= dx;
    }
    capped_goal_ = true;
  } else {
    capped_goal_ = false;
  }
}

void ZeroedStateFeedbackLoop::RecalculatePowerGoal() {
  if (index() == 0) {
    mutable_R(2, 0) = (-plant().A(1, 0) / plant().A(1, 2) * R(0, 0) -
                       plant().A(1, 1) / plant().A(1, 2) * R(1, 0));
  } else {
    mutable_R(2, 0) = -plant().A(1, 1) / plant().A(1, 2) * R(1, 0);
  }
}

void ZeroedStateFeedbackLoop::SetCalibration(double encoder_val,
                                             double known_position) {
  double previous_offset = offset_;
  offset_ = known_position - encoder_val;
  double doffset = offset_ - previous_offset;
  mutable_X_hat(0, 0) += doffset;
  // Offset the goal so we don't move.
  mutable_R(0, 0) += doffset;
  if (index() == 0) {
    mutable_R(2, 0) += -plant().A(1, 0) / plant().A(1, 2) * (doffset);
  }
}

ShooterMotor::ShooterMotor(::aos::EventLoop *event_loop,
                           const ::std::string &name)
    : frc971::controls::ControlLoop<Goal, Position, Status, Output>(event_loop,
                                                                    name),
      shooter_(MakeShooterLoop()),
      state_(STATE_INITIALIZE),
      cycles_not_moved_(0),
      shot_count_(0),
      zeroed_(false),
      distal_posedge_validation_cycles_left_(0),
      proximal_posedge_validation_cycles_left_(0),
      last_distal_current_(true),
      last_proximal_current_(true) {}

double ShooterMotor::PowerToPosition(double power) {
  const constants::Values &values = constants::GetValues();
  double maxpower = 0.5 * kSpringConstant *
                    (kMaxExtension * kMaxExtension -
                     (kMaxExtension - values.shooter.upper_limit) *
                         (kMaxExtension - values.shooter.upper_limit));
  if (power < 0) {
    power = 0;
  } else if (power > maxpower) {
    power = maxpower;
  }

  double mp = kMaxExtension * kMaxExtension - (power + power) / kSpringConstant;
  double new_pos = 0.10;
  if (mp < 0) {
    AOS_LOG(ERROR,
            "Power calculation has negative number before square root (%f).\n",
            mp);
  } else {
    new_pos = kMaxExtension - ::std::sqrt(mp);
  }

  new_pos = ::std::min(::std::max(new_pos, values.shooter.lower_limit),
                       values.shooter.upper_limit);
  return new_pos;
}

double ShooterMotor::PositionToPower(double position) {
  double power = kSpringConstant * position * (kMaxExtension - position / 2.0);
  return power;
}

void ShooterMotor::CheckCalibrations(const Position *position) {
  AOS_CHECK_NOTNULL(position);
  const constants::Values &values = constants::GetValues();

  // TODO(austin): Validate that this is the right edge.
  // If we see a posedge on any of the hall effects,
  if (position->pusher_proximal()->posedge_count() !=
          last_proximal_posedge_count_ &&
      !last_proximal_current_) {
    proximal_posedge_validation_cycles_left_ = 2;
  }
  if (proximal_posedge_validation_cycles_left_ > 0) {
    if (position->pusher_proximal()->current()) {
      --proximal_posedge_validation_cycles_left_;
      if (proximal_posedge_validation_cycles_left_ == 0) {
        shooter_.SetCalibration(position->pusher_proximal()->posedge_value(),
                                values.shooter.pusher_proximal.upper_angle);

        AOS_LOG(DEBUG, "Setting calibration using proximal sensor\n");
        zeroed_ = true;
      }
    } else {
      proximal_posedge_validation_cycles_left_ = 0;
    }
  }

  if (position->pusher_distal()->posedge_count() !=
          last_distal_posedge_count_ &&
      !last_distal_current_) {
    distal_posedge_validation_cycles_left_ = 2;
  }
  if (distal_posedge_validation_cycles_left_ > 0) {
    if (position->pusher_distal()->current()) {
      --distal_posedge_validation_cycles_left_;
      if (distal_posedge_validation_cycles_left_ == 0) {
        shooter_.SetCalibration(position->pusher_distal()->posedge_value(),
                                values.shooter.pusher_distal.upper_angle);

        AOS_LOG(DEBUG, "Setting calibration using distal sensor\n");
        zeroed_ = true;
      }
    } else {
      distal_posedge_validation_cycles_left_ = 0;
    }
  }
}

// Positive is out, and positive power is out.
void ShooterMotor::RunIteration(const Goal *goal, const Position *position,
                                aos::Sender<Output>::Builder *output,
                                aos::Sender<Status>::Builder *status) {
  OutputT output_struct;
  const monotonic_clock::time_point monotonic_now =
      event_loop()->monotonic_now();
  if (goal && ::std::isnan(goal->shot_power())) {
    state_ = STATE_ESTOP;
    AOS_LOG(ERROR, "Estopping because got a shot power of NAN.\n");
  }

  // we must always have these or we have issues.
  if (status == NULL) {
    if (output) output_struct.voltage = 0;
    AOS_LOG(ERROR, "Thought I would just check for null and die.\n");
    return;
  }
  bool status_ready = false;

  if (WasReset()) {
    state_ = STATE_INITIALIZE;
    last_distal_current_ = position->pusher_distal()->current();
    last_proximal_current_ = position->pusher_proximal()->current();
  }
  if (position) {
    shooter_.CorrectPosition(position->position());
  }

  // Disable the motors now so that all early returns will return with the
  // motors disabled.
  if (output) output_struct.voltage = 0;

  const constants::Values &values = constants::GetValues();

  // Don't even let the control loops run.
  bool shooter_loop_disable = false;

  const bool disabled = !has_joystick_state() || !joystick_state().enabled();

  // If true, move the goal if we saturate.
  bool cap_goal = false;

  // TODO(austin): Move the offset if we see or don't see a hall effect when we
  // expect to see one.
  // Probably not needed yet.

  if (position) {
    int last_index = shooter_.index();
    if (position->plunger() && position->latch()) {
      // Use the controller without the spring if the latch is set and the
      // plunger is back
      shooter_.set_index(1);
    } else {
      // Otherwise use the controller with the spring.
      shooter_.set_index(0);
    }
    if (shooter_.index() != last_index) {
      shooter_.RecalculatePowerGoal();
    }
  }

  switch (state_) {
    case STATE_INITIALIZE:
      if (position) {
        // Reinitialize the internal filter state.
        shooter_.InitializeState(position->position());

        // Start off with the assumption that we are at the value
        // futhest back given our sensors.
        if (position->pusher_distal()->current()) {
          shooter_.SetCalibration(position->position(),
                                  values.shooter.pusher_distal.lower_angle);
        } else if (position->pusher_proximal()->current()) {
          shooter_.SetCalibration(position->position(),
                                  values.shooter.pusher_proximal.upper_angle);
        } else {
          shooter_.SetCalibration(position->position(),
                                  values.shooter.upper_limit);
        }

        // Go to the current position.
        shooter_.SetGoalPosition(shooter_.absolute_position(), 0.0);
        // If the plunger is all the way back, we want to be latched.
        latch_piston_ = position->plunger();
        brake_piston_ = false;
        if (position->latch() == latch_piston_) {
          state_ = STATE_REQUEST_LOAD;
        } else {
          shooter_loop_disable = true;
          AOS_LOG(DEBUG,
                  "Not moving on until the latch has moved to avoid a crash\n");
        }
      } else {
        // If we can't start yet because we don't know where we are, set the
        // latch and brake to their defaults.
        latch_piston_ = true;
        brake_piston_ = true;
      }
      break;
    case STATE_REQUEST_LOAD:
      if (position) {
        zeroed_ = false;
        if (position->pusher_distal()->current() ||
            position->pusher_proximal()->current()) {
          // We started on the sensor, back up until we are found.
          // If the plunger is all the way back and not latched, it won't be
          // there for long.
          state_ = STATE_LOAD_BACKTRACK;

          // The plunger is already back and latched.  Don't release it.
          if (position->plunger() && position->latch()) {
            latch_piston_ = true;
          } else {
            latch_piston_ = false;
          }
        } else if (position->plunger() && position->latch()) {
          // The plunger is back and we are latched.  We most likely got here
          // from Initialize, in which case we want to 'load' again anyways to
          // zero.
          Load(monotonic_now);
          latch_piston_ = true;
        } else {
          // Off the sensor, start loading.
          Load(monotonic_now);
          latch_piston_ = false;
        }
      }

      // Hold our current position.
      shooter_.SetGoalPosition(shooter_.absolute_position(), 0.0);
      brake_piston_ = false;
      break;
    case STATE_LOAD_BACKTRACK:
      // If we are here, then that means we started past the edge where we want
      // to zero.  Move backwards until we don't see the sensor anymore.
      // The plunger is contacting the pusher (or will be shortly).

      if (!disabled) {
        shooter_.SetGoalPosition(
            shooter_.goal_position() + values.shooter.zeroing_speed * kDt,
            values.shooter.zeroing_speed);
      }
      cap_goal = true;
      shooter_.set_max_voltage(4.0);

      if (position) {
        if (!position->pusher_distal()->current() &&
            !position->pusher_proximal()->current()) {
          Load(monotonic_now);
        }
        latch_piston_ = position->plunger();
      }

      brake_piston_ = false;
      break;
    case STATE_LOAD:
      // If we are disabled right now, reset the timer.
      if (disabled) {
        Load(monotonic_now);
        // Latch defaults to true when disabled.  Leave it latched until we have
        // useful sensor data.
        latch_piston_ = true;
      }
      if (output == nullptr) {
        load_timeout_ += ::frc971::controls::kLoopFrequency;
      }
      // Go to 0, which should be the latch position, or trigger a hall effect
      // on the way.  If we don't see edges where we are supposed to, the
      // offset will be updated by code above.
      shooter_.SetGoalPosition(0.0, 0.0);

      if (position) {
        CheckCalibrations(position);

        // Latch if the plunger is far enough back to trigger the hall effect.
        // This happens when the distal sensor is triggered.
        latch_piston_ =
            position->pusher_distal()->current() || position->plunger();

        // Check if we are latched and back.  Make sure the plunger is all the
        // way back as well.
        if (position->plunger() && position->latch() &&
            position->pusher_distal()->current()) {
          if (!zeroed_) {
            state_ = STATE_REQUEST_LOAD;
          } else {
            state_ = STATE_PREPARE_SHOT;
          }
        } else if (position->plunger() &&
                   ::std::abs(shooter_.absolute_position() -
                              shooter_.goal_position()) < 0.001) {
          // We are at the goal, but not latched.
          state_ = STATE_LOADING_PROBLEM;
          loading_problem_end_time_ = monotonic_now + kLoadProblemEndTimeout;
        }
      }
      if (load_timeout_ < monotonic_now) {
        if (position) {
          // If none of the sensors is triggered, estop.
          // Otherwise, trigger anyways if it has been 0.5 seconds more.
          if (!(position->pusher_distal()->current() ||
                position->pusher_proximal()->current()) ||
              (load_timeout_ + chrono::milliseconds(500) < monotonic_now)) {
            state_ = STATE_ESTOP;
            AOS_LOG(ERROR, "Estopping because took too long to load.\n");
          }
        }
      }
      brake_piston_ = false;
      break;
    case STATE_LOADING_PROBLEM:
      if (disabled) {
        state_ = STATE_REQUEST_LOAD;
        break;
      }
      // We got to the goal, but the latch hasn't registered as down.  It might
      // be stuck, or on it's way but not there yet.
      if (monotonic_now > loading_problem_end_time_) {
        // Timeout by unloading.
        Unload(monotonic_now);
      } else if (position && position->plunger() && position->latch()) {
        // If both trigger, we are latched.
        state_ = STATE_PREPARE_SHOT;
      }
      // Move a bit further back to help it trigger.
      // If the latch is slow due to the air flowing through the tubes or
      // inertia, but is otherwise free, this won't have much time to do
      // anything and is safe.  Otherwise this gives us a bit more room to free
      // up the latch.
      shooter_.SetGoalPosition(values.shooter.lower_limit, 0.0);
      if (position) {
        AOS_LOG(DEBUG, "Waiting on latch: plunger %d, latch: %d\n",
                position->plunger(), position->latch());
      }

      latch_piston_ = true;
      brake_piston_ = false;
      break;
    case STATE_PREPARE_SHOT:
      // Move the shooter to the shot power set point and then lock the brake.
      // TODO(austin): Timeout.  Low priority.

      if (goal) {
        shooter_.SetGoalPosition(PowerToPosition(goal->shot_power()), 0.0);
      }

      AOS_LOG(DEBUG, "PDIFF: absolute_position: %.2f, pow: %.2f\n",
              shooter_.absolute_position(),
              goal ? PowerToPosition(goal->shot_power())
                   : ::std::numeric_limits<double>::quiet_NaN());
      if (goal &&
          ::std::abs(shooter_.absolute_position() -
                     PowerToPosition(goal->shot_power())) < 0.001 &&
          ::std::abs(shooter_.absolute_velocity()) < 0.005) {
        // We are there, set the brake and move on.
        latch_piston_ = true;
        brake_piston_ = true;
        shooter_brake_set_time_ = monotonic_now + kShooterBrakeSetTime;
        state_ = STATE_READY;
      } else {
        latch_piston_ = true;
        brake_piston_ = false;
      }
      if (goal && goal->unload_requested()) {
        Unload(monotonic_now);
      }
      break;
    case STATE_READY:
      AOS_LOG(DEBUG, "In ready\n");
      // Wait until the brake is set, and a shot is requested or the shot power
      // is changed.
      if (monotonic_now > shooter_brake_set_time_) {
        status_ready = true;
        // We have waited long enough for the brake to set, turn the shooter
        // control loop off.
        shooter_loop_disable = true;
        AOS_LOG(DEBUG, "Brake is now set\n");
        if (goal && goal->shot_requested() && !disabled) {
          AOS_LOG(DEBUG, "Shooting now\n");
          shooter_loop_disable = true;
          shot_end_time_ = monotonic_now + kShotEndTimeout;
          firing_starting_position_ = shooter_.absolute_position();
          state_ = STATE_FIRE;
        }
      }
      if (state_ == STATE_READY && goal &&
          ::std::abs(shooter_.absolute_position() -
                     PowerToPosition(goal->shot_power())) > 0.002) {
        // TODO(austin): Add a state to release the brake.

        // TODO(austin): Do we want to set the brake here or after shooting?
        // Depends on air usage.
        status_ready = false;
        AOS_LOG(DEBUG, "Preparing shot again.\n");
        state_ = STATE_PREPARE_SHOT;
      }

      if (goal) {
        shooter_.SetGoalPosition(PowerToPosition(goal->shot_power()), 0.0);
      }

      latch_piston_ = true;
      brake_piston_ = true;

      if (goal && goal->unload_requested()) {
        Unload(monotonic_now);
      }
      break;

    case STATE_FIRE:
      if (disabled) {
        if (position) {
          if (position->plunger()) {
            // If disabled and the plunger is still back there, reset the
            // timeout.
            shot_end_time_ = monotonic_now + kShotEndTimeout;
          }
        }
      }
      shooter_loop_disable = true;
      // Count the number of contiguous cycles during which we haven't moved.
      if (::std::abs(last_position_position_ - shooter_.absolute_position()) <
          0.0005) {
        ++cycles_not_moved_;
      } else {
        cycles_not_moved_ = 0;
      }

      // If we have moved any amount since the start and the shooter has now
      // been still for a couple cycles, the shot finished.
      // Also move on if it times out.
      if (((::std::abs(firing_starting_position_ -
                       shooter_.absolute_position()) > 0.0005 &&
            cycles_not_moved_ > 6) ||
           monotonic_now > shot_end_time_) &&
          robot_state().voltage_battery() > 10.5) {
        state_ = STATE_REQUEST_LOAD;
        ++shot_count_;
      }
      latch_piston_ = false;
      brake_piston_ = true;
      break;
    case STATE_UNLOAD:
      // Reset the timeouts.
      if (disabled) Unload(monotonic_now);

      // If it is latched and the plunger is back, move the pusher back to catch
      // the plunger.
      bool all_back;
      if (position) {
        all_back = position->plunger() && position->latch();
      } else {
        all_back = last_position_plunger_ && last_position_latch_;
      }

      if (all_back) {
        // Pull back to 0, 0.
        shooter_.SetGoalPosition(0.0, 0.0);
        if (shooter_.absolute_position() < 0.005) {
          // When we are close enough, 'fire'.
          latch_piston_ = false;
        } else {
          latch_piston_ = true;

          if (position) {
            CheckCalibrations(position);
          }
        }
      } else {
        // The plunger isn't all the way back, or it is and it is unlatched, so
        // we can now unload.
        shooter_.SetGoalPosition(shooter_.absolute_position(), 0.0);
        latch_piston_ = false;
        state_ = STATE_UNLOAD_MOVE;
        unload_timeout_ = monotonic_now + kUnloadTimeout;
      }

      if (monotonic_now > unload_timeout_) {
        // We have been stuck trying to unload for way too long, give up and
        // turn everything off.
        state_ = STATE_ESTOP;
        AOS_LOG(ERROR, "Estopping because took too long to unload.\n");
      }

      brake_piston_ = false;
      break;
    case STATE_UNLOAD_MOVE: {
      if (disabled) {
        unload_timeout_ = monotonic_now + kUnloadTimeout;
        shooter_.SetGoalPosition(shooter_.absolute_position(), 0.0);
      }
      cap_goal = true;
      shooter_.set_max_voltage(6.0);

      // Slowly move back until we hit the upper limit.
      // If we were at the limit last cycle, we are done unloading.
      // This is because if we saturate, we might hit the limit before we are
      // actually there.
      if (shooter_.goal_position() >= values.shooter.upper_limit) {
        shooter_.SetGoalPosition(values.shooter.upper_limit, 0.0);
        // We don't want the loop fighting the spring when we are unloaded.
        // Turn it off.
        shooter_loop_disable = true;
        state_ = STATE_READY_UNLOAD;
      } else {
        shooter_.SetGoalPosition(
            ::std::min(
                values.shooter.upper_limit,
                shooter_.goal_position() + values.shooter.unload_speed * kDt),
            values.shooter.unload_speed);
      }

      latch_piston_ = false;
      brake_piston_ = false;
    } break;
    case STATE_READY_UNLOAD:
      if (goal && goal->load_requested()) {
        state_ = STATE_REQUEST_LOAD;
      }
      // If we are ready to load again,
      shooter_loop_disable = true;

      latch_piston_ = false;
      brake_piston_ = false;
      break;

    case STATE_ESTOP:
      AOS_LOG(WARNING, "estopped\n");
      // Totally lost, go to a safe state.
      shooter_loop_disable = true;
      latch_piston_ = true;
      brake_piston_ = true;
      break;
  }

  if (!shooter_loop_disable) {
    if (!cap_goal) {
      shooter_.set_max_voltage(12.0);
    }
    shooter_.Update(output == NULL);
    if (cap_goal) {
      shooter_.CapGoal();
    }
    // We don't really want to output anything if we went through everything
    // assuming the motors weren't working.
    if (output) output_struct.voltage = shooter_.voltage();
  } else {
    shooter_.Update(true);
    shooter_.ZeroPower();
    if (output) output_struct.voltage = 0.0;
  }

  Status::Builder status_builder = status->MakeBuilder<Status>();

  status_builder.add_ready(status_ready);
  status_builder.add_hard_stop_power(
      PositionToPower(shooter_.absolute_position()));

  if (output) {
    output_struct.latch_piston = latch_piston_;
    output_struct.brake_piston = brake_piston_;

    output->CheckOk(output->Send(Output::Pack(*output->fbb(), &output_struct)));
  }

  if (position) {
    last_position_latch_ = position->latch();
    last_position_plunger_ = position->plunger();
    last_position_position_ = position->position();

    last_distal_posedge_count_ = position->pusher_distal()->posedge_count();
    last_proximal_posedge_count_ = position->pusher_proximal()->posedge_count();
    last_distal_current_ = position->pusher_distal()->current();
    last_proximal_current_ = position->pusher_proximal()->current();
  }

  status_builder.add_absolute_position(shooter_.absolute_position());
  status_builder.add_absolute_velocity(shooter_.absolute_velocity());
  status_builder.add_state(state_);

  status_builder.add_shots(shot_count_);

  (void)status->Send(status_builder.Finish());
}

flatbuffers::Offset<Output> ShooterMotor::Zero(
    aos::Sender<Output>::Builder *output) {
  Output::Builder output_builder = output->MakeBuilder<Output>();
  output_builder.add_voltage(0.0);
  output_builder.add_latch_piston(latch_piston_);
  output_builder.add_brake_piston(brake_piston_);
  return output_builder.Finish();
}

}  // namespace y2014::control_loops::shooter