Copy back a lot of the 2014 code.

Change-Id: I552292d8bd7bce4409e02d254bef06a9cc009568
diff --git a/y2014/control_loops/claw/claw.cc b/y2014/control_loops/claw/claw.cc
new file mode 100644
index 0000000..b2ac562
--- /dev/null
+++ b/y2014/control_loops/claw/claw.cc
@@ -0,0 +1,994 @@
+#include "y2014/control_loops/claw/claw.h"
+
+#include <algorithm>
+
+#include "aos/common/controls/control_loops.q.h"
+#include "aos/common/logging/logging.h"
+#include "aos/common/logging/queue_logging.h"
+#include "aos/common/logging/matrix_logging.h"
+#include "aos/common/commonmath.h"
+
+#include "y2014/constants.h"
+#include "y2014/control_loops/claw/claw_motor_plant.h"
+
+// Zeroing plan.
+// There are 2 types of zeros.  Enabled and disabled ones.
+// Disabled ones are only valid during auto mode, and can be used to speed up
+// the enabled zero process.  We need to re-zero during teleop in case the auto
+// zero was poor and causes us to miss all our shots.
+//
+// We need to be able to zero manually while disabled by moving the joint over
+// the zeros.
+// Zero on the down edge when disabled (gravity in the direction of motion)
+//
+// When enabled, zero on the up edge (gravity opposing the direction of motion)
+// The enabled sequence needs to work as follows.  We can crash the claw if we
+// bring them too close to each other or too far from each other.  The only safe
+// thing to do is to move them in unison.
+//
+// Start by moving them both towards the front of the bot to either find either
+// the middle hall effect on either jaw, or the front hall effect on the bottom
+// jaw.  Any edge that isn't the desired edge will provide an approximate edge
+// location that can be used for the fine tuning step.
+// Once an edge is found on the front claw, move back the other way with both
+// claws until an edge is found for the other claw.
+// Now that we have an approximate zero, we can robustify the limits to keep
+// both claws safe.  Then, we can move both claws to a position that is the
+// correct side of the zero and go zero.
+
+// Valid region plan.
+// Difference between the arms has a range, and the values of each arm has a
+// range.
+// If a claw runs up against a static limit, don't let the goal change outside
+// the limit.
+// If a claw runs up against a movable limit, move both claws outwards to get
+// out of the condition.
+
+namespace frc971 {
+namespace control_loops {
+
+static const double kZeroingVoltage = 4.0;
+static const double kMaxVoltage = 12.0;
+const double kRezeroThreshold = 0.07;
+
+ClawLimitedLoop::ClawLimitedLoop(StateFeedbackLoop<4, 2, 2> &&loop)
+    : StateFeedbackLoop<4, 2, 2>(::std::move(loop)),
+      uncapped_average_voltage_(0.0),
+      is_zeroing_(true),
+      U_Poly_((Eigen::Matrix<double, 4, 2>() << 1, 0,
+               -1, 0,
+               0, 1,
+               0, -1).finished(),
+              (Eigen::Matrix<double, 4, 1>() << kMaxVoltage, kMaxVoltage,
+               kMaxVoltage, kMaxVoltage).finished()),
+      U_Poly_zeroing_((Eigen::Matrix<double, 4, 2>() << 1, 0,
+               -1, 0,
+               0, 1,
+               0, -1).finished(),
+              (Eigen::Matrix<double, 4, 1>() <<
+               kZeroingVoltage, kZeroingVoltage,
+               kZeroingVoltage, kZeroingVoltage).finished()) {
+  ::aos::controls::HPolytope<0>::Init();
+}
+
+// Caps the voltage prioritizing reducing velocity error over reducing
+// positional error.
+// Uses the polytope libararies which we used to just use for the drivetrain.
+// Uses a region representing the maximum voltage and then transforms it such
+// that the points represent different amounts of positional error and
+// constrains the region such that, if at all possible, it will maintain its
+// current efforts to reduce velocity error.
+void ClawLimitedLoop::CapU() {
+  const Eigen::Matrix<double, 4, 1> error = R() - X_hat();
+
+  double u_top = U(1, 0);
+  double u_bottom = U(0, 0);
+
+  uncapped_average_voltage_ = (u_top + u_bottom) / 2;
+
+  double max_voltage = is_zeroing_ ? kZeroingVoltage : kMaxVoltage;
+
+  if (::std::abs(u_bottom) > max_voltage || ::std::abs(u_top) > max_voltage) {
+    LOG_MATRIX(DEBUG, "U at start", U());
+    // H * U <= k
+    // U = UPos + UVel
+    // H * (UPos + UVel) <= k
+    // H * UPos <= k - H * UVel
+
+    // Now, we can do a coordinate transformation and say the following.
+
+    // UPos = position_K * position_error
+    // (H * position_K) * position_error <= k - H * UVel
+
+    Eigen::Matrix<double, 2, 2> position_K;
+    position_K << K(0, 0), K(0, 1),
+                  K(1, 0), K(1, 1);
+    Eigen::Matrix<double, 2, 2> velocity_K;
+    velocity_K << K(0, 2), K(0, 3),
+                  K(1, 2), K(1, 3);
+
+    Eigen::Matrix<double, 2, 1> position_error;
+    position_error << error(0, 0), error(1, 0);
+    Eigen::Matrix<double, 2, 1> velocity_error;
+    velocity_error << error(2, 0), error(3, 0);
+    LOG_MATRIX(DEBUG, "error", error);
+
+    const auto &poly = is_zeroing_ ? U_Poly_zeroing_ : U_Poly_;
+    const Eigen::Matrix<double, 4, 2> pos_poly_H = poly.H() * position_K;
+    const Eigen::Matrix<double, 4, 1> pos_poly_k =
+        poly.k() - poly.H() * velocity_K * velocity_error;
+    const ::aos::controls::HPolytope<2> pos_poly(pos_poly_H, pos_poly_k);
+
+    Eigen::Matrix<double, 2, 1> adjusted_pos_error;
+    {
+      const auto &P = position_error;
+
+      // This line was at 45 degrees but is now at some angle steeper than the
+      // straight one between the points.
+      Eigen::Matrix<double, 1, 2> angle_45;
+      // If the top claw is above its soft upper limit, make the line actually
+      // 45 degrees to avoid smashing it into the limit in an attempt to fix the
+      // separation error faster than the bottom position one.
+      if (X_hat(0, 0) + X_hat(1, 0) >
+          constants::GetValues().claw.upper_claw.upper_limit) {
+        angle_45 << 1, 1;
+      } else {
+        // Fixing separation error half as fast as positional error works well
+        // because it means they both close evenly.
+        angle_45 << ::std::sqrt(3), 1;
+      }
+      Eigen::Matrix<double, 1, 2> L45_quadrant;
+      L45_quadrant << ::aos::sign(P(1, 0)), -::aos::sign(P(0, 0));
+      const auto L45 = L45_quadrant.cwiseProduct(angle_45);
+      const double w45 = 0;
+
+      Eigen::Matrix<double, 1, 2> LH;
+      if (::std::abs(P(0, 0)) > ::std::abs(P(1, 0))) {
+        LH << 0, 1;
+      } else {
+        LH << 1, 0;
+      }
+      const double wh = LH.dot(P);
+
+      Eigen::Matrix<double, 2, 2> standard;
+      standard << L45, LH;
+      Eigen::Matrix<double, 2, 1> W;
+      W << w45, wh;
+      const Eigen::Matrix<double, 2, 1> intersection = standard.inverse() * W;
+
+      bool is_inside_h;
+      const auto adjusted_pos_error_h =
+          DoCoerceGoal(pos_poly, LH, wh, position_error, &is_inside_h);
+      const auto adjusted_pos_error_45 =
+          DoCoerceGoal(pos_poly, L45, w45, intersection, nullptr);
+      if (pos_poly.IsInside(intersection)) {
+        adjusted_pos_error = adjusted_pos_error_h;
+      } else {
+        if (is_inside_h) {
+          if (adjusted_pos_error_h.norm() > adjusted_pos_error_45.norm()) {
+            adjusted_pos_error = adjusted_pos_error_h;
+          } else {
+            adjusted_pos_error = adjusted_pos_error_45;
+          }
+        } else {
+          adjusted_pos_error = adjusted_pos_error_45;
+        }
+      }
+    }
+
+    LOG_MATRIX(DEBUG, "adjusted_pos_error", adjusted_pos_error);
+    mutable_U() = velocity_K * velocity_error + position_K * adjusted_pos_error;
+    LOG_MATRIX(DEBUG, "U is now", U());
+
+    {
+      const auto values = constants::GetValues().claw;
+      if (top_known_) {
+        if (X_hat(0, 0) + X_hat(1, 0) > values.upper_claw.upper_limit && U(1, 0) > 0) {
+          LOG(WARNING, "upper claw too high and moving up\n");
+          mutable_U(1, 0) = 0;
+        } else if (X_hat(0, 0) + X_hat(1, 0) < values.upper_claw.lower_limit &&
+                   U(1, 0) < 0) {
+          LOG(WARNING, "upper claw too low and moving down\n");
+          mutable_U(1, 0) = 0;
+        }
+      }
+      if (bottom_known_) {
+        if (X_hat(0, 0) > values.lower_claw.upper_limit && U(0, 0) > 0) {
+          LOG(WARNING, "lower claw too high and moving up\n");
+          mutable_U(0, 0) = 0;
+        } else if (X_hat(0, 0) < values.lower_claw.lower_limit && U(0, 0) < 0) {
+          LOG(WARNING, "lower claw too low and moving down\n");
+          mutable_U(0, 0) = 0;
+        }
+      }
+    }
+  }
+}
+
+ZeroedStateFeedbackLoop::ZeroedStateFeedbackLoop(const char *name,
+                                                 ClawMotor *motor)
+    : offset_(0.0),
+      name_(name),
+      motor_(motor),
+      zeroing_state_(UNKNOWN_POSITION),
+      posedge_value_(0.0),
+      negedge_value_(0.0),
+      encoder_(0.0),
+      last_encoder_(0.0) {}
+
+void ZeroedStateFeedbackLoop::SetPositionValues(const HalfClawPosition &claw) {
+  front_.Update(claw.front);
+  calibration_.Update(claw.calibration);
+  back_.Update(claw.back);
+
+  bool any_sensor_triggered = any_triggered();
+  if (any_sensor_triggered && any_triggered_last_) {
+    // We are still on the hall effect and nothing has changed.
+    min_hall_effect_on_angle_ =
+        ::std::min(min_hall_effect_on_angle_, claw.position);
+    max_hall_effect_on_angle_ =
+        ::std::max(max_hall_effect_on_angle_, claw.position);
+  } else if (!any_sensor_triggered && !any_triggered_last_) {
+    // We are still off the hall effect and nothing has changed.
+    min_hall_effect_off_angle_ =
+        ::std::min(min_hall_effect_off_angle_, claw.position);
+    max_hall_effect_off_angle_ =
+        ::std::max(max_hall_effect_off_angle_, claw.position);
+  } else if (any_sensor_triggered && !any_triggered_last_) {
+    // Saw a posedge on the hall effect.  Reset the limits.
+    min_hall_effect_on_angle_ = ::std::min(claw.posedge_value, claw.position);
+    max_hall_effect_on_angle_ = ::std::max(claw.posedge_value, claw.position);
+  } else if (!any_sensor_triggered && any_triggered_last_) {
+    // Saw a negedge on the hall effect.  Reset the limits.
+    min_hall_effect_off_angle_ = ::std::min(claw.negedge_value, claw.position);
+    max_hall_effect_off_angle_ = ::std::max(claw.negedge_value, claw.position);
+  }
+
+  posedge_value_ = claw.posedge_value;
+  negedge_value_ = claw.negedge_value;
+  last_encoder_ = encoder_;
+  if (front().value() || calibration().value() || back().value()) {
+    last_on_encoder_ = encoder_;
+  } else {
+    last_off_encoder_ = encoder_;
+  }
+  encoder_ = claw.position;
+  any_triggered_last_ = any_sensor_triggered;
+}
+
+void ZeroedStateFeedbackLoop::Reset(const HalfClawPosition &claw) {
+  set_zeroing_state(ZeroedStateFeedbackLoop::UNKNOWN_POSITION);
+
+  front_.Reset(claw.front);
+  calibration_.Reset(claw.calibration);
+  back_.Reset(claw.back);
+  // close up the min and max edge positions as they are no longer valid and
+  // will be expanded in future iterations
+  min_hall_effect_on_angle_ = claw.position;
+  max_hall_effect_on_angle_ = claw.position;
+  min_hall_effect_off_angle_ = claw.position;
+  max_hall_effect_off_angle_ = claw.position;
+  any_triggered_last_ = any_triggered();
+}
+
+bool TopZeroedStateFeedbackLoop::SetCalibrationOnEdge(
+    const constants::Values::Claws::Claw &claw_values,
+    JointZeroingState zeroing_state) {
+  double edge_encoder;
+  double edge_angle;
+  if (GetPositionOfEdge(claw_values, &edge_encoder, &edge_angle)) {
+    LOG(INFO, "Calibration edge edge should be %f.\n", edge_angle);
+    SetCalibration(edge_encoder, edge_angle);
+    set_zeroing_state(zeroing_state);
+    return true;
+  }
+  return false;
+}
+
+void TopZeroedStateFeedbackLoop::HandleCalibrationError(
+    const constants::Values::Claws::Claw &claw_values) {
+  double edge_encoder;
+  double edge_angle;
+  if (GetPositionOfEdge(claw_values, &edge_encoder, &edge_angle)) {
+    const double calibration_error =
+        ComputeCalibrationChange(edge_encoder, edge_angle);
+    LOG(INFO, "Top calibration error is %f\n", calibration_error);
+    if (::std::abs(calibration_error) > kRezeroThreshold) {
+      LOG(WARNING, "rezeroing top\n");
+      SetCalibration(edge_encoder, edge_angle);
+      set_zeroing_state(ZeroedStateFeedbackLoop::UNKNOWN_POSITION);
+    }
+  }
+}
+
+
+void BottomZeroedStateFeedbackLoop::HandleCalibrationError(
+    const constants::Values::Claws::Claw &claw_values) {
+  double edge_encoder;
+  double edge_angle;
+  if (GetPositionOfEdge(claw_values, &edge_encoder, &edge_angle)) {
+    const double calibration_error =
+        ComputeCalibrationChange(edge_encoder, edge_angle);
+    LOG(INFO, "Bottom calibration error is %f\n", calibration_error);
+    if (::std::abs(calibration_error) > kRezeroThreshold) {
+      LOG(WARNING, "rezeroing bottom\n");
+      SetCalibration(edge_encoder, edge_angle);
+      set_zeroing_state(ZeroedStateFeedbackLoop::UNKNOWN_POSITION);
+    }
+  }
+}
+
+bool BottomZeroedStateFeedbackLoop::SetCalibrationOnEdge(
+    const constants::Values::Claws::Claw &claw_values,
+    JointZeroingState zeroing_state) {
+  double edge_encoder;
+  double edge_angle;
+  if (GetPositionOfEdge(claw_values, &edge_encoder, &edge_angle)) {
+    LOG(INFO, "Calibration edge.\n");
+    SetCalibration(edge_encoder, edge_angle);
+    set_zeroing_state(zeroing_state);
+    return true;
+  }
+  return false;
+}
+
+ClawMotor::ClawMotor(control_loops::ClawGroup *my_claw)
+    : aos::controls::ControlLoop<control_loops::ClawGroup>(my_claw),
+      has_top_claw_goal_(false),
+      top_claw_goal_(0.0),
+      top_claw_(this),
+      has_bottom_claw_goal_(false),
+      bottom_claw_goal_(0.0),
+      bottom_claw_(this),
+      claw_(MakeClawLoop()),
+      was_enabled_(false),
+      doing_calibration_fine_tune_(false),
+      capped_goal_(false),
+      mode_(UNKNOWN_LOCATION) {}
+
+const int ZeroedStateFeedbackLoop::kZeroingMaxVoltage;
+
+bool ZeroedStateFeedbackLoop::SawFilteredPosedge(
+    const HallEffectTracker &this_sensor, const HallEffectTracker &sensorA,
+    const HallEffectTracker &sensorB) {
+  if (posedge_filter_ == nullptr && this_sensor.posedge_count_changed() &&
+      !sensorA.posedge_count_changed() && !sensorB.posedge_count_changed() &&
+      this_sensor.value() && !this_sensor.last_value()) {
+    posedge_filter_ = &this_sensor;
+  } else if (posedge_filter_ == &this_sensor &&
+             !this_sensor.posedge_count_changed() &&
+             !sensorA.posedge_count_changed() &&
+             !sensorB.posedge_count_changed() && this_sensor.value()) {
+    posedge_filter_ = nullptr;
+    return true;
+  } else if (posedge_filter_ == &this_sensor) {
+    posedge_filter_ = nullptr;
+  }
+  return false;
+}
+
+bool ZeroedStateFeedbackLoop::SawFilteredNegedge(
+    const HallEffectTracker &this_sensor, const HallEffectTracker &sensorA,
+    const HallEffectTracker &sensorB) {
+  if (negedge_filter_ == nullptr && this_sensor.negedge_count_changed() &&
+      !sensorA.negedge_count_changed() && !sensorB.negedge_count_changed() &&
+      !this_sensor.value() && this_sensor.last_value()) {
+    negedge_filter_ = &this_sensor;
+  } else if (negedge_filter_ == &this_sensor &&
+             !this_sensor.negedge_count_changed() &&
+             !sensorA.negedge_count_changed() &&
+             !sensorB.negedge_count_changed() && !this_sensor.value()) {
+    negedge_filter_ = nullptr;
+    return true;
+  } else if (negedge_filter_ == &this_sensor) {
+    negedge_filter_ = nullptr;
+  }
+  return false;
+}
+
+bool ZeroedStateFeedbackLoop::DoGetPositionOfEdge(
+    const constants::Values::Claws::AnglePair &angles, double *edge_encoder,
+    double *edge_angle, const HallEffectTracker &this_sensor,
+    const HallEffectTracker &sensorA, const HallEffectTracker &sensorB,
+    const char *hall_effect_name) {
+  bool found_edge = false;
+
+  if (SawFilteredPosedge(this_sensor, sensorA, sensorB)) {
+    if (min_hall_effect_off_angle_ == max_hall_effect_off_angle_) {
+      LOG(WARNING, "%s: Uncertain which side, rejecting posedge\n", name_);
+    } else {
+      const double average_last_encoder =
+          (min_hall_effect_off_angle_ + max_hall_effect_off_angle_) / 2.0;
+      if (posedge_value_ < average_last_encoder) {
+        *edge_angle = angles.upper_decreasing_angle;
+        LOG(INFO, "%s Posedge upper of %s -> %f posedge: %f avg_encoder: %f\n",
+            name_, hall_effect_name, *edge_angle, posedge_value_,
+            average_last_encoder);
+      } else {
+        *edge_angle = angles.lower_angle;
+        LOG(INFO, "%s Posedge lower of %s -> %f posedge: %f avg_encoder: %f\n",
+            name_, hall_effect_name, *edge_angle, posedge_value_,
+            average_last_encoder);
+      }
+      *edge_encoder = posedge_value_;
+      found_edge = true;
+    }
+  }
+
+  if (SawFilteredNegedge(this_sensor, sensorA, sensorB)) {
+    if (min_hall_effect_on_angle_ == max_hall_effect_on_angle_) {
+      LOG(WARNING, "%s: Uncertain which side, rejecting negedge\n", name_);
+    } else {
+      const double average_last_encoder =
+          (min_hall_effect_on_angle_ + max_hall_effect_on_angle_) / 2.0;
+      if (negedge_value_ > average_last_encoder) {
+        *edge_angle = angles.upper_angle;
+        LOG(INFO, "%s Negedge upper of %s -> %f negedge: %f avg_encoder: %f\n",
+            name_, hall_effect_name, *edge_angle, negedge_value_,
+            average_last_encoder);
+      } else {
+        *edge_angle = angles.lower_decreasing_angle;
+        LOG(INFO, "%s Negedge lower of %s -> %f negedge: %f avg_encoder: %f\n",
+            name_, hall_effect_name, *edge_angle, negedge_value_,
+            average_last_encoder);
+      }
+      *edge_encoder = negedge_value_;
+      found_edge = true;
+    }
+  }
+
+  return found_edge;
+}
+
+bool ZeroedStateFeedbackLoop::GetPositionOfEdge(
+    const constants::Values::Claws::Claw &claw_values, double *edge_encoder,
+    double *edge_angle) {
+  if (DoGetPositionOfEdge(claw_values.front, edge_encoder, edge_angle, front_,
+                          calibration_, back_, "front")) {
+    return true;
+  }
+  if (DoGetPositionOfEdge(claw_values.calibration, edge_encoder, edge_angle,
+                          calibration_, front_, back_, "calibration")) {
+    return true;
+  }
+  if (DoGetPositionOfEdge(claw_values.back, edge_encoder, edge_angle, back_,
+                          calibration_, front_, "back")) {
+    return true;
+  }
+  return false;
+}
+
+void TopZeroedStateFeedbackLoop::SetCalibration(double edge_encoder,
+                                                double edge_angle) {
+  double old_offset = offset_;
+  offset_ = edge_angle - edge_encoder;
+  const double doffset = offset_ - old_offset;
+  motor_->ChangeTopOffset(doffset);
+}
+
+double TopZeroedStateFeedbackLoop::ComputeCalibrationChange(double edge_encoder,
+                                                            double edge_angle) {
+  const double offset = edge_angle - edge_encoder;
+  const double doffset = offset - offset_;
+  return doffset;
+}
+
+void BottomZeroedStateFeedbackLoop::SetCalibration(double edge_encoder,
+                                                   double edge_angle) {
+  double old_offset = offset_;
+  offset_ = edge_angle - edge_encoder;
+  const double doffset = offset_ - old_offset;
+  motor_->ChangeBottomOffset(doffset);
+}
+
+double BottomZeroedStateFeedbackLoop::ComputeCalibrationChange(
+    double edge_encoder, double edge_angle) {
+  const double offset = edge_angle - edge_encoder;
+  const double doffset = offset - offset_;
+  return doffset;
+}
+
+void ClawMotor::ChangeTopOffset(double doffset) {
+  claw_.ChangeTopOffset(doffset);
+  if (has_top_claw_goal_) {
+    top_claw_goal_ += doffset;
+  }
+}
+
+void ClawMotor::ChangeBottomOffset(double doffset) {
+  claw_.ChangeBottomOffset(doffset);
+  if (has_bottom_claw_goal_) {
+    bottom_claw_goal_ += doffset;
+  }
+}
+
+void ClawLimitedLoop::ChangeTopOffset(double doffset) {
+  mutable_Y()(1, 0) += doffset;
+  mutable_X_hat()(1, 0) += doffset;
+  LOG(INFO, "Changing top offset by %f\n", doffset);
+}
+void ClawLimitedLoop::ChangeBottomOffset(double doffset) {
+  mutable_Y()(0, 0) += doffset;
+  mutable_X_hat()(0, 0) += doffset;
+  mutable_X_hat()(1, 0) -= doffset;
+  LOG(INFO, "Changing bottom offset by %f\n", doffset);
+}
+
+void LimitClawGoal(double *bottom_goal, double *top_goal,
+                   const frc971::constants::Values &values) {
+  // first update position based on angle limit
+  const double separation = *top_goal - *bottom_goal;
+  if (separation > values.claw.soft_max_separation) {
+    LOG_STRUCT(DEBUG, "before", ClawPositionToLog(*top_goal, *bottom_goal));
+    const double dsep = (separation - values.claw.soft_max_separation) / 2.0;
+    *bottom_goal += dsep;
+    *top_goal -= dsep;
+    LOG_STRUCT(DEBUG, "after", ClawPositionToLog(*top_goal, *bottom_goal));
+  }
+  if (separation < values.claw.soft_min_separation) {
+    LOG_STRUCT(DEBUG, "before", ClawPositionToLog(*top_goal, *bottom_goal));
+    const double dsep = (separation - values.claw.soft_min_separation) / 2.0;
+    *bottom_goal += dsep;
+    *top_goal -= dsep;
+    LOG_STRUCT(DEBUG, "after", ClawPositionToLog(*top_goal, *bottom_goal));
+  }
+
+  // now move both goals in unison
+  if (*bottom_goal < values.claw.lower_claw.lower_limit) {
+    LOG_STRUCT(DEBUG, "before", ClawPositionToLog(*top_goal, *bottom_goal));
+    *top_goal += values.claw.lower_claw.lower_limit - *bottom_goal;
+    *bottom_goal = values.claw.lower_claw.lower_limit;
+    LOG_STRUCT(DEBUG, "after", ClawPositionToLog(*top_goal, *bottom_goal));
+  }
+  if (*bottom_goal > values.claw.lower_claw.upper_limit) {
+    LOG_STRUCT(DEBUG, "before", ClawPositionToLog(*top_goal, *bottom_goal));
+    *top_goal -= *bottom_goal - values.claw.lower_claw.upper_limit;
+    *bottom_goal = values.claw.lower_claw.upper_limit;
+    LOG_STRUCT(DEBUG, "after", ClawPositionToLog(*top_goal, *bottom_goal));
+  }
+
+  if (*top_goal < values.claw.upper_claw.lower_limit) {
+    LOG_STRUCT(DEBUG, "before", ClawPositionToLog(*top_goal, *bottom_goal));
+    *bottom_goal += values.claw.upper_claw.lower_limit - *top_goal;
+    *top_goal = values.claw.upper_claw.lower_limit;
+    LOG_STRUCT(DEBUG, "after", ClawPositionToLog(*top_goal, *bottom_goal));
+  }
+  if (*top_goal > values.claw.upper_claw.upper_limit) {
+    LOG_STRUCT(DEBUG, "before", ClawPositionToLog(*top_goal, *bottom_goal));
+    *bottom_goal -= *top_goal - values.claw.upper_claw.upper_limit;
+    *top_goal = values.claw.upper_claw.upper_limit;
+    LOG_STRUCT(DEBUG, "after", ClawPositionToLog(*top_goal, *bottom_goal));
+  }
+}
+
+bool ClawMotor::is_ready() const {
+  return (
+      (top_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED &&
+       bottom_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED) ||
+      (((::aos::joystick_state.get() == NULL)
+            ? true
+            : ::aos::joystick_state->autonomous) &&
+       ((top_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED ||
+         top_claw_.zeroing_state() ==
+             ZeroedStateFeedbackLoop::DISABLED_CALIBRATION) &&
+        (bottom_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED ||
+         bottom_claw_.zeroing_state() ==
+             ZeroedStateFeedbackLoop::DISABLED_CALIBRATION))));
+}
+
+bool ClawMotor::is_zeroing() const { return !is_ready(); }
+
+// Positive angle is up, and positive power is up.
+void ClawMotor::RunIteration(const control_loops::ClawGroup::Goal *goal,
+                             const control_loops::ClawGroup::Position *position,
+                             control_loops::ClawGroup::Output *output,
+                             control_loops::ClawGroup::Status *status) {
+  constexpr double dt = 0.01;
+
+  // Disable the motors now so that all early returns will return with the
+  // motors disabled.
+  if (output) {
+    output->top_claw_voltage = 0;
+    output->bottom_claw_voltage = 0;
+    output->intake_voltage = 0;
+    output->tusk_voltage = 0;
+  }
+
+  if (goal) {
+    if (::std::isnan(goal->bottom_angle) ||
+        ::std::isnan(goal->separation_angle) || ::std::isnan(goal->intake) ||
+        ::std::isnan(goal->centering)) {
+      return;
+    }
+  }
+
+  if (WasReset()) {
+    top_claw_.Reset(position->top);
+    bottom_claw_.Reset(position->bottom);
+  }
+
+  const frc971::constants::Values &values = constants::GetValues();
+
+  if (position) {
+    Eigen::Matrix<double, 2, 1> Y;
+    Y << position->bottom.position + bottom_claw_.offset(),
+        position->top.position + top_claw_.offset();
+    claw_.Correct(Y);
+
+    top_claw_.SetPositionValues(position->top);
+    bottom_claw_.SetPositionValues(position->bottom);
+
+    if (!has_top_claw_goal_) {
+      has_top_claw_goal_ = true;
+      top_claw_goal_ = top_claw_.absolute_position();
+      initial_separation_ =
+          top_claw_.absolute_position() - bottom_claw_.absolute_position();
+    }
+    if (!has_bottom_claw_goal_) {
+      has_bottom_claw_goal_ = true;
+      bottom_claw_goal_ = bottom_claw_.absolute_position();
+      initial_separation_ =
+          top_claw_.absolute_position() - bottom_claw_.absolute_position();
+    }
+    LOG_STRUCT(DEBUG, "absolute position",
+               ClawPositionToLog(top_claw_.absolute_position(),
+                                 bottom_claw_.absolute_position()));
+  }
+
+  bool autonomous, enabled;
+  if (::aos::joystick_state.get() == nullptr) {
+    autonomous = true;
+    enabled = false;
+  } else {
+    autonomous = ::aos::joystick_state->autonomous;
+    enabled = ::aos::joystick_state->enabled;
+  }
+
+  double bottom_claw_velocity_ = 0.0;
+  double top_claw_velocity_ = 0.0;
+
+  if (goal != NULL &&
+      ((top_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED &&
+        bottom_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED) ||
+       (autonomous &&
+        ((top_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED ||
+          top_claw_.zeroing_state() ==
+              ZeroedStateFeedbackLoop::DISABLED_CALIBRATION) &&
+         (bottom_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED ||
+          bottom_claw_.zeroing_state() ==
+              ZeroedStateFeedbackLoop::DISABLED_CALIBRATION))))) {
+    // Ready to use the claw.
+    // Limit the goals here.
+    bottom_claw_goal_ = goal->bottom_angle;
+    top_claw_goal_ = goal->bottom_angle + goal->separation_angle;
+    has_bottom_claw_goal_ = true;
+    has_top_claw_goal_ = true;
+    doing_calibration_fine_tune_ = false;
+    mode_ = READY;
+
+    bottom_claw_.HandleCalibrationError(values.claw.lower_claw);
+    top_claw_.HandleCalibrationError(values.claw.upper_claw);
+  } else if (top_claw_.zeroing_state() !=
+             ZeroedStateFeedbackLoop::UNKNOWN_POSITION &&
+             bottom_claw_.zeroing_state() !=
+             ZeroedStateFeedbackLoop::UNKNOWN_POSITION) {
+    // Time to fine tune the zero.
+    // Limit the goals here.
+    if (!enabled) {
+      // If we are disabled, start the fine tune process over again.
+      doing_calibration_fine_tune_ = false;
+    }
+    if (bottom_claw_.zeroing_state() != ZeroedStateFeedbackLoop::CALIBRATED) {
+      // always get the bottom claw to calibrated first
+      LOG(DEBUG, "Calibrating the bottom of the claw\n");
+      if (!doing_calibration_fine_tune_) {
+        if (::std::abs(bottom_absolute_position() -
+                       values.claw.start_fine_tune_pos) <
+            values.claw.claw_unimportant_epsilon) {
+          doing_calibration_fine_tune_ = true;
+          bottom_claw_goal_ += values.claw.claw_zeroing_speed * dt;
+          top_claw_velocity_ = bottom_claw_velocity_ =
+              values.claw.claw_zeroing_speed;
+          LOG(DEBUG, "Ready to fine tune the bottom\n");
+          mode_ = FINE_TUNE_BOTTOM;
+        } else {
+          // send bottom to zeroing start
+          bottom_claw_goal_ = values.claw.start_fine_tune_pos;
+          LOG(DEBUG, "Going to the start position for the bottom\n");
+          mode_ = PREP_FINE_TUNE_BOTTOM;
+        }
+      } else {
+        mode_ = FINE_TUNE_BOTTOM;
+        bottom_claw_goal_ += values.claw.claw_zeroing_speed * dt;
+        top_claw_velocity_ = bottom_claw_velocity_ =
+            values.claw.claw_zeroing_speed;
+        if (top_claw_.front_or_back_triggered() ||
+            bottom_claw_.front_or_back_triggered()) {
+          // We shouldn't hit a limit, but if we do, go back to the zeroing
+          // point and try again.
+          doing_calibration_fine_tune_ = false;
+          bottom_claw_goal_ = values.claw.start_fine_tune_pos;
+          top_claw_velocity_ = bottom_claw_velocity_ = 0.0;
+          LOG(DEBUG, "Found a limit, starting over.\n");
+          mode_ = PREP_FINE_TUNE_BOTTOM;
+        }
+
+        if (position && bottom_claw_.SawFilteredPosedge(
+                            bottom_claw_.calibration(), bottom_claw_.front(),
+                            bottom_claw_.back())) {
+          // do calibration
+          bottom_claw_.SetCalibration(
+              position->bottom.posedge_value,
+              values.claw.lower_claw.calibration.lower_angle);
+          bottom_claw_.set_zeroing_state(ZeroedStateFeedbackLoop::CALIBRATED);
+          // calibrated so we are done fine tuning bottom
+          doing_calibration_fine_tune_ = false;
+          LOG(DEBUG, "Calibrated the bottom correctly!\n");
+        } else if (bottom_claw_.calibration().last_value()) {
+          LOG(DEBUG, "Aborting bottom fine tune because sensor triggered\n");
+          doing_calibration_fine_tune_ = false;
+          bottom_claw_.set_zeroing_state(
+              ZeroedStateFeedbackLoop::UNKNOWN_POSITION);
+        } else {
+          LOG(DEBUG, "Fine tuning\n");
+        }
+      }
+      // now set the top claw to track
+
+      top_claw_goal_ = bottom_claw_goal_ + values.claw.claw_zeroing_separation;
+    } else {
+      // bottom claw must be calibrated, start on the top
+      if (!doing_calibration_fine_tune_) {
+        if (::std::abs(top_absolute_position() -
+                       values.claw.start_fine_tune_pos) <
+            values.claw.claw_unimportant_epsilon) {
+          doing_calibration_fine_tune_ = true;
+          top_claw_goal_ += values.claw.claw_zeroing_speed * dt;
+          top_claw_velocity_ = bottom_claw_velocity_ =
+              values.claw.claw_zeroing_speed;
+          LOG(DEBUG, "Ready to fine tune the top\n");
+          mode_ = FINE_TUNE_TOP;
+        } else {
+          // send top to zeroing start
+          top_claw_goal_ = values.claw.start_fine_tune_pos;
+          LOG(DEBUG, "Going to the start position for the top\n");
+          mode_ = PREP_FINE_TUNE_TOP;
+        }
+      } else {
+        mode_ = FINE_TUNE_TOP;
+        top_claw_goal_ += values.claw.claw_zeroing_speed * dt;
+        top_claw_velocity_ = bottom_claw_velocity_ =
+            values.claw.claw_zeroing_speed;
+        if (top_claw_.front_or_back_triggered() ||
+            bottom_claw_.front_or_back_triggered()) {
+          // this should not happen, but now we know it won't
+          doing_calibration_fine_tune_ = false;
+          top_claw_goal_ = values.claw.start_fine_tune_pos;
+          top_claw_velocity_ = bottom_claw_velocity_ = 0.0;
+          LOG(DEBUG, "Found a limit, starting over.\n");
+          mode_ = PREP_FINE_TUNE_TOP;
+        }
+
+        if (position &&
+            top_claw_.SawFilteredPosedge(top_claw_.calibration(),
+                                         top_claw_.front(), top_claw_.back())) {
+          // do calibration
+          top_claw_.SetCalibration(
+              position->top.posedge_value,
+              values.claw.upper_claw.calibration.lower_angle);
+          top_claw_.set_zeroing_state(ZeroedStateFeedbackLoop::CALIBRATED);
+          // calibrated so we are done fine tuning top
+          doing_calibration_fine_tune_ = false;
+          LOG(DEBUG, "Calibrated the top correctly!\n");
+        } else if (top_claw_.calibration().last_value()) {
+          LOG(DEBUG, "Aborting top fine tune because sensor triggered\n");
+          doing_calibration_fine_tune_ = false;
+          top_claw_.set_zeroing_state(
+              ZeroedStateFeedbackLoop::UNKNOWN_POSITION);
+        }
+      }
+      // now set the bottom claw to track
+      bottom_claw_goal_ = top_claw_goal_ - values.claw.claw_zeroing_separation;
+    }
+  } else {
+    doing_calibration_fine_tune_ = false;
+    if (!was_enabled_ && enabled) {
+      if (position) {
+        top_claw_goal_ = position->top.position + top_claw_.offset();
+        bottom_claw_goal_ = position->bottom.position + bottom_claw_.offset();
+        initial_separation_ =
+            position->top.position - position->bottom.position;
+      } else {
+        has_top_claw_goal_ = false;
+        has_bottom_claw_goal_ = false;
+      }
+    }
+
+    if ((bottom_claw_.zeroing_state() !=
+             ZeroedStateFeedbackLoop::UNKNOWN_POSITION ||
+         bottom_claw_.front().value() || top_claw_.front().value()) &&
+        !top_claw_.back().value() && !bottom_claw_.back().value()) {
+      if (enabled) {
+        // Time to slowly move back up to find any position to narrow down the
+        // zero.
+        top_claw_goal_ += values.claw.claw_zeroing_off_speed * dt;
+        bottom_claw_goal_ += values.claw.claw_zeroing_off_speed * dt;
+        top_claw_velocity_ = bottom_claw_velocity_ =
+            values.claw.claw_zeroing_off_speed;
+        LOG(DEBUG, "Bottom is known.\n");
+      }
+    } else {
+      // We don't know where either claw is.  Slowly start moving down to find
+      // any hall effect.
+      if (enabled) {
+        top_claw_goal_ -= values.claw.claw_zeroing_off_speed * dt;
+        bottom_claw_goal_ -= values.claw.claw_zeroing_off_speed * dt;
+        top_claw_velocity_ = bottom_claw_velocity_ =
+            -values.claw.claw_zeroing_off_speed;
+        LOG(DEBUG, "Both are unknown.\n");
+      }
+    }
+
+    if (position) {
+      if (enabled) {
+        top_claw_.SetCalibrationOnEdge(
+            values.claw.upper_claw,
+            ZeroedStateFeedbackLoop::APPROXIMATE_CALIBRATION);
+        bottom_claw_.SetCalibrationOnEdge(
+            values.claw.lower_claw,
+            ZeroedStateFeedbackLoop::APPROXIMATE_CALIBRATION);
+      } else {
+        // TODO(austin): Only calibrate on the predetermined edge.
+        // We might be able to just ignore this since the backlash is soooo
+        // low.
+        // :)
+        top_claw_.SetCalibrationOnEdge(
+            values.claw.upper_claw,
+            ZeroedStateFeedbackLoop::DISABLED_CALIBRATION);
+        bottom_claw_.SetCalibrationOnEdge(
+            values.claw.lower_claw,
+            ZeroedStateFeedbackLoop::DISABLED_CALIBRATION);
+      }
+    }
+    mode_ = UNKNOWN_LOCATION;
+  }
+
+  // Limit the goals if both claws have been (mostly) found.
+  if (mode_ != UNKNOWN_LOCATION) {
+    LimitClawGoal(&bottom_claw_goal_, &top_claw_goal_, values);
+  }
+
+  claw_.set_positions_known(
+      top_claw_.zeroing_state() != ZeroedStateFeedbackLoop::UNKNOWN_POSITION,
+      bottom_claw_.zeroing_state() !=
+          ZeroedStateFeedbackLoop::UNKNOWN_POSITION);
+  if (has_top_claw_goal_ && has_bottom_claw_goal_) {
+    claw_.mutable_R() << bottom_claw_goal_, top_claw_goal_ - bottom_claw_goal_,
+        bottom_claw_velocity_, top_claw_velocity_ - bottom_claw_velocity_;
+    LOG_MATRIX(DEBUG, "actual goal", claw_.R());
+
+    // Only cap power when one of the halves of the claw is moving slowly and
+    // could wind up.
+    claw_.set_is_zeroing(mode_ == UNKNOWN_LOCATION || mode_ == FINE_TUNE_TOP ||
+                         mode_ == FINE_TUNE_BOTTOM);
+    claw_.Update(output == nullptr);
+  } else {
+    claw_.Update(true);
+  }
+
+  capped_goal_ = false;
+  switch (mode_) {
+    case READY:
+    case PREP_FINE_TUNE_TOP:
+    case PREP_FINE_TUNE_BOTTOM:
+      break;
+    case FINE_TUNE_BOTTOM:
+    case FINE_TUNE_TOP:
+    case UNKNOWN_LOCATION: {
+      if (claw_.uncapped_average_voltage() > values.claw.max_zeroing_voltage) {
+        double dx_bot = (claw_.U_uncapped(0, 0) -
+                     values.claw.max_zeroing_voltage) /
+                    claw_.K(0, 0);
+        double dx_top = (claw_.U_uncapped(1, 0) -
+                     values.claw.max_zeroing_voltage) /
+                    claw_.K(0, 0);
+        double dx = ::std::max(dx_top, dx_bot);
+        bottom_claw_goal_ -= dx;
+        top_claw_goal_ -= dx;
+        Eigen::Matrix<double, 4, 1> R;
+        R << bottom_claw_goal_, top_claw_goal_ - bottom_claw_goal_, claw_.R(2, 0),
+            claw_.R(3, 0);
+        claw_.mutable_U() = claw_.K() * (R - claw_.X_hat());
+        capped_goal_ = true;
+        LOG(DEBUG, "Moving the goal by %f to prevent windup."
+            " Uncapped is %f, max is %f, difference is %f\n",
+            dx,
+            claw_.uncapped_average_voltage(), values.claw.max_zeroing_voltage,
+            (claw_.uncapped_average_voltage() -
+             values.claw.max_zeroing_voltage));
+      } else if (claw_.uncapped_average_voltage() <
+                 -values.claw.max_zeroing_voltage) {
+        double dx_bot = (claw_.U_uncapped(0, 0) +
+                     values.claw.max_zeroing_voltage) /
+                    claw_.K(0, 0);
+        double dx_top = (claw_.U_uncapped(1, 0) +
+                     values.claw.max_zeroing_voltage) /
+                    claw_.K(0, 0);
+        double dx = ::std::min(dx_top, dx_bot);
+        bottom_claw_goal_ -= dx;
+        top_claw_goal_ -= dx;
+        Eigen::Matrix<double, 4, 1> R;
+        R << bottom_claw_goal_, top_claw_goal_ - bottom_claw_goal_, claw_.R(2, 0),
+            claw_.R(3, 0);
+        claw_.mutable_U() = claw_.K() * (R - claw_.X_hat());
+        capped_goal_ = true;
+        LOG(DEBUG, "Moving the goal by %f to prevent windup\n", dx);
+      }
+    } break;
+  }
+
+  if (output) {
+    if (goal) {
+      //setup the intake
+      output->intake_voltage =
+          (goal->intake > 12.0) ? 12 : (goal->intake < -12.0) ? -12.0
+                                                              : goal->intake;
+      output->tusk_voltage = goal->centering;
+      output->tusk_voltage =
+          (goal->centering > 12.0) ? 12 : (goal->centering < -12.0)
+              ? -12.0
+              : goal->centering;
+    }
+    output->top_claw_voltage = claw_.U(1, 0);
+    output->bottom_claw_voltage = claw_.U(0, 0);
+
+    if (output->top_claw_voltage > kMaxVoltage) {
+      output->top_claw_voltage = kMaxVoltage;
+    } else if (output->top_claw_voltage < -kMaxVoltage) {
+      output->top_claw_voltage = -kMaxVoltage;
+    }
+
+    if (output->bottom_claw_voltage > kMaxVoltage) {
+      output->bottom_claw_voltage = kMaxVoltage;
+    } else if (output->bottom_claw_voltage < -kMaxVoltage) {
+      output->bottom_claw_voltage = -kMaxVoltage;
+    }
+  }
+
+  status->bottom = bottom_absolute_position();
+  status->separation = top_absolute_position() - bottom_absolute_position();
+  status->bottom_velocity = claw_.X_hat(2, 0);
+  status->separation_velocity = claw_.X_hat(3, 0);
+
+  if (goal) {
+    bool bottom_done =
+        ::std::abs(bottom_absolute_position() - goal->bottom_angle) < 0.020;
+    bool bottom_velocity_done = ::std::abs(status->bottom_velocity) < 0.2;
+    bool separation_done =
+        ::std::abs((top_absolute_position() - bottom_absolute_position()) -
+                   goal->separation_angle) < 0.020;
+    bool separation_done_with_ball =
+        ::std::abs((top_absolute_position() - bottom_absolute_position()) -
+                   goal->separation_angle) < 0.06;
+    status->done = is_ready() && separation_done && bottom_done && bottom_velocity_done;
+    status->done_with_ball =
+        is_ready() && separation_done_with_ball && bottom_done && bottom_velocity_done;
+  } else {
+    status->done = status->done_with_ball = false;
+  }
+
+  status->zeroed = is_ready();
+  status->zeroed_for_auto =
+      (top_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED ||
+       top_claw_.zeroing_state() ==
+           ZeroedStateFeedbackLoop::DISABLED_CALIBRATION) &&
+      (bottom_claw_.zeroing_state() == ZeroedStateFeedbackLoop::CALIBRATED ||
+       bottom_claw_.zeroing_state() ==
+           ZeroedStateFeedbackLoop::DISABLED_CALIBRATION);
+
+  was_enabled_ = enabled;
+}
+
+}  // namespace control_loops
+}  // namespace frc971
+