Add shooter class and python.

Change-Id: I27b4c8f282a0b80344a7df59cf3b04569d9c8110
diff --git a/y2020/control_loops/superstructure/accelerator/BUILD b/y2020/control_loops/superstructure/accelerator/BUILD
new file mode 100644
index 0000000..2c680bf
--- /dev/null
+++ b/y2020/control_loops/superstructure/accelerator/BUILD
@@ -0,0 +1,17 @@
+package(default_visibility = ["//visibility:public"])
+
+load("@com_github_google_flatbuffers//:build_defs.bzl", "flatbuffer_cc_library")
+
+genrule(
+    name = "genrule_accelerator",
+    outs = [
+        "accelerator_plant.h",
+        "accelerator_plant.cc",
+        "accelerator_integral_plant.h",
+        "accelerator_integral_plant.cc",
+    ],
+    cmd = "$(location //y2020/control_loops/python:accelerator) $(OUTS)",
+    tools = [
+        "//y2020/control_loops/python:accelerator",
+    ],
+)
diff --git a/y2020/control_loops/superstructure/finisher/BUILD b/y2020/control_loops/superstructure/finisher/BUILD
new file mode 100644
index 0000000..b9bfc4f
--- /dev/null
+++ b/y2020/control_loops/superstructure/finisher/BUILD
@@ -0,0 +1,17 @@
+package(default_visibility = ["//visibility:public"])
+
+load("@com_github_google_flatbuffers//:build_defs.bzl", "flatbuffer_cc_library")
+
+genrule(
+    name = "genrule_finisher",
+    outs = [
+        "finisher_plant.h",
+        "finisher_plant.cc",
+        "finisher_integral_plant.h",
+        "finisher_integral_plant.cc",
+    ],
+    cmd = "$(location //y2020/control_loops/python:finisher) $(OUTS)",
+    tools = [
+        "//y2020/control_loops/python:finisher",
+    ],
+)
diff --git a/y2020/control_loops/superstructure/shooter/BUILD b/y2020/control_loops/superstructure/shooter/BUILD
new file mode 100644
index 0000000..d63231b
--- /dev/null
+++ b/y2020/control_loops/superstructure/shooter/BUILD
@@ -0,0 +1,58 @@
+package(default_visibility = ["//visibility:public"])
+
+load("@com_github_google_flatbuffers//:build_defs.bzl", "flatbuffer_cc_library")
+
+cc_library(
+    name = "shooter_plants",
+    srcs = [
+        "//y2020/control_loops/superstructure/accelerator:accelerator_integral_plant.cc",
+        "//y2020/control_loops/superstructure/accelerator:accelerator_plant.cc",
+        "//y2020/control_loops/superstructure/finisher:finisher_integral_plant.cc",
+        "//y2020/control_loops/superstructure/finisher:finisher_plant.cc",
+    ],
+    hdrs = [
+        "//y2020/control_loops/superstructure/accelerator:accelerator_integral_plant.h",
+        "//y2020/control_loops/superstructure/accelerator:accelerator_plant.h",
+        "//y2020/control_loops/superstructure/finisher:finisher_integral_plant.h",
+        "//y2020/control_loops/superstructure/finisher:finisher_plant.h",
+    ],
+    deps = [
+        "//frc971/control_loops:state_feedback_loop",
+    ],
+)
+
+cc_library(
+    name = "shooter",
+    srcs = [
+        "shooter.cc",
+    ],
+    hdrs = [
+        "shooter.h",
+    ],
+    deps = [
+        ":flywheel_controller",
+        "//aos/controls:control_loop",
+        "//frc971/control_loops:profiled_subsystem",
+        "//y2020/control_loops/superstructure:superstructure_goal_fbs",
+        "//y2020/control_loops/superstructure:superstructure_output_fbs",
+        "//y2020/control_loops/superstructure:superstructure_position_fbs",
+        "//y2020/control_loops/superstructure:superstructure_status_fbs",
+    ],
+)
+
+cc_library(
+    name = "flywheel_controller",
+    srcs = [
+        "flywheel_controller.cc",
+    ],
+    hdrs = [
+        "flywheel_controller.h",
+    ],
+    deps = [
+        ":shooter_plants",
+        "//aos/controls:control_loop",
+        "//frc971/control_loops:profiled_subsystem",
+        "//y2020/control_loops/superstructure:superstructure_goal_fbs",
+        "//y2020/control_loops/superstructure:superstructure_status_fbs",
+    ],
+)
diff --git a/y2020/control_loops/superstructure/shooter/flywheel_controller.cc b/y2020/control_loops/superstructure/shooter/flywheel_controller.cc
new file mode 100644
index 0000000..0f920a4
--- /dev/null
+++ b/y2020/control_loops/superstructure/shooter/flywheel_controller.cc
@@ -0,0 +1,70 @@
+#include "y2020/control_loops/superstructure/shooter/flywheel_controller.h"
+
+#include <chrono>
+
+#include "aos/logging/logging.h"
+#include "y2020/control_loops/superstructure/accelerator/accelerator_plant.h"
+#include "y2020/control_loops/superstructure/finisher/finisher_plant.h"
+
+namespace y2020 {
+namespace control_loops {
+namespace superstructure {
+namespace shooter {
+
+FlywheelController::FlywheelController(StateFeedbackLoop<3, 1, 1> &&loop)
+    : loop_(new StateFeedbackLoop<3, 1, 1>(std::move(loop))) {
+  history_.fill(0);
+  Y_.setZero();
+}
+
+void FlywheelController::set_goal(double angular_velocity_goal) {
+  loop_->mutable_next_R() << 0.0, angular_velocity_goal, 0.0;
+  last_goal_ = angular_velocity_goal;
+}
+
+void FlywheelController::set_position(double current_position) {
+  // Update position in the model.
+  Y_ << current_position;
+
+  // Add the position to the history.
+  history_[history_position_] = current_position;
+  history_position_ = (history_position_ + 1) % kHistoryLength;
+}
+
+double FlywheelController::voltage() const { return loop_->U(0, 0); }
+
+void FlywheelController::Update(bool disabled) {
+  loop_->mutable_R() = loop_->next_R();
+  if (loop_->R(1, 0) < 1.0) {
+    // Kill power at low angular velocities.
+    disabled = true;
+  }
+
+  loop_->Correct(Y_);
+  loop_->Update(disabled);
+}
+
+flatbuffers::Offset<FlywheelControllerStatus> FlywheelController::SetStatus(
+    flatbuffers::FlatBufferBuilder *fbb) {
+  // Compute the oldest point in the history.
+  const int oldest_history_position =
+      ((history_position_ == 0) ? kHistoryLength : history_position_) - 1;
+
+  // Compute the distance moved over that time period.
+  const double avg_angular_velocity =
+      (history_[oldest_history_position] - history_[history_position_]) /
+      (::aos::time::DurationInSeconds(::aos::controls::kLoopFrequency) *
+       static_cast<double>(kHistoryLength - 1));
+
+  FlywheelControllerStatusBuilder builder(*fbb);
+
+  builder.add_avg_angular_velocity(avg_angular_velocity);
+  builder.add_angular_velocity(loop_->X_hat(1, 0));
+  builder.add_angular_velocity_goal(last_goal_);
+  return builder.Finish();
+}
+
+}  // namespace shooter
+}  // namespace superstructure
+}  // namespace control_loops
+}  // namespace y2020
diff --git a/y2020/control_loops/superstructure/shooter/flywheel_controller.h b/y2020/control_loops/superstructure/shooter/flywheel_controller.h
new file mode 100644
index 0000000..20cd681
--- /dev/null
+++ b/y2020/control_loops/superstructure/shooter/flywheel_controller.h
@@ -0,0 +1,61 @@
+#ifndef Y2020_CONTROL_LOOPS_SHOOTER_FLYWHEEL_CONTROLLER_H_
+#define Y2020_CONTROL_LOOPS_SHOOTER_FLYWHEEL_CONTROLLER_H_
+
+#include <memory>
+
+#include "aos/controls/control_loop.h"
+#include "aos/time/time.h"
+#include "frc971/control_loops/state_feedback_loop.h"
+#include "y2020/control_loops/superstructure/accelerator/accelerator_integral_plant.h"
+#include "y2020/control_loops/superstructure/finisher/finisher_integral_plant.h"
+#include "y2020/control_loops/superstructure/superstructure_status_generated.h"
+
+namespace y2020 {
+namespace control_loops {
+namespace superstructure {
+namespace shooter {
+
+// Handles the velocity control of each flywheel.
+class FlywheelController {
+ public:
+  FlywheelController(StateFeedbackLoop<3, 1, 1> &&loop);
+
+  // Sets the velocity goal in radians/sec
+  void set_goal(double angular_velocity_goal);
+  // Sets the current encoder position in radians
+  void set_position(double current_position);
+
+  // Populates the status structure.
+  flatbuffers::Offset<FlywheelControllerStatus> SetStatus(
+      flatbuffers::FlatBufferBuilder *fbb);
+
+  // Returns the control loop calculated voltage.
+  double voltage() const;
+
+  // Returns the instantaneous velocity.
+  double velocity() const { return loop_->X_hat(1, 0); }
+
+  // Executes the control loop for a cycle.
+  void Update(bool disabled);
+
+ private:
+  // The current sensor measurement.
+  Eigen::Matrix<double, 1, 1> Y_;
+  // The control loop.
+  ::std::unique_ptr<StateFeedbackLoop<3, 1, 1>> loop_;
+
+  // History array for calculating a filtered angular velocity.
+  static constexpr int kHistoryLength = 10;
+  ::std::array<double, kHistoryLength> history_;
+  ptrdiff_t history_position_ = 0;
+  double last_goal_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(FlywheelController);
+};
+
+}  // namespace shooter
+}  // namespace superstructure
+}  // namespace control_loops
+}  // namespace y2020
+
+#endif  // Y2020_CONTROL_LOOPS_SHOOTER_FLYWHEEL_CONTROLLER_H_
diff --git a/y2020/control_loops/superstructure/shooter/shooter.cc b/y2020/control_loops/superstructure/shooter/shooter.cc
new file mode 100644
index 0000000..6a1d201
--- /dev/null
+++ b/y2020/control_loops/superstructure/shooter/shooter.cc
@@ -0,0 +1,62 @@
+#include "y2020/control_loops/superstructure/shooter/shooter.h"
+
+#include <chrono>
+
+#include "aos/logging/logging.h"
+#include "y2020/control_loops/superstructure/accelerator/accelerator_plant.h"
+#include "y2020/control_loops/superstructure/finisher/finisher_plant.h"
+
+namespace y2020 {
+namespace control_loops {
+namespace superstructure {
+namespace shooter {
+
+Shooter::Shooter()
+    : finisher_(finisher::MakeIntegralFinisherLoop()),
+      accelerator_left_(accelerator::MakeIntegralAcceleratorLoop()),
+      accelerator_right_(accelerator::MakeIntegralAcceleratorLoop()) {}
+
+flatbuffers::Offset<ShooterStatus> Shooter::RunIteration(
+    const ShooterGoal *goal, const ShooterPosition *position,
+    flatbuffers::FlatBufferBuilder *fbb, OutputT *output) {
+  if (goal) {
+    // Update position/goal for our two shooter sides.
+    finisher_.set_goal(goal->velocity_finisher());
+    accelerator_left_.set_goal(goal->velocity_accelerator());
+    accelerator_right_.set_goal(goal->velocity_accelerator());
+  }
+
+  finisher_.set_position(position->theta_finisher());
+  accelerator_left_.set_position(position->theta_accelerator_left());
+  accelerator_right_.set_position(position->theta_accelerator_right());
+
+  finisher_.Update(output == nullptr);
+  accelerator_left_.Update(output == nullptr);
+  accelerator_right_.Update(output == nullptr);
+
+  flatbuffers::Offset<FlywheelControllerStatus> finisher_status_offset =
+      finisher_.SetStatus(fbb);
+  flatbuffers::Offset<FlywheelControllerStatus> accelerator_left_status_offset =
+      accelerator_left_.SetStatus(fbb);
+  flatbuffers::Offset<FlywheelControllerStatus>
+      accelerator_right_status_offset = accelerator_right_.SetStatus(fbb);
+
+  ShooterStatusBuilder status_builder(*fbb);
+
+  status_builder.add_finisher(finisher_status_offset);
+  status_builder.add_accelerator_left(accelerator_left_status_offset);
+  status_builder.add_accelerator_right(accelerator_right_status_offset);
+
+  if (output) {
+    output->finisher_voltage = finisher_.voltage();
+    output->accelerator_left_voltage = accelerator_left_.voltage();
+    output->accelerator_right_voltage = accelerator_right_.voltage();
+  }
+
+  return status_builder.Finish();
+}
+
+}  // namespace shooter
+}  // namespace superstructure
+}  // namespace control_loops
+}  // namespace y2020
diff --git a/y2020/control_loops/superstructure/shooter/shooter.h b/y2020/control_loops/superstructure/shooter/shooter.h
new file mode 100644
index 0000000..88bcb3b
--- /dev/null
+++ b/y2020/control_loops/superstructure/shooter/shooter.h
@@ -0,0 +1,37 @@
+#ifndef Y2020_CONTROL_LOOPS_SHOOTER_SHOOTER_H_
+#define Y2020_CONTROL_LOOPS_SHOOTER_SHOOTER_H_
+
+#include "aos/controls/control_loop.h"
+#include "frc971/control_loops/state_feedback_loop.h"
+#include "y2020/control_loops/superstructure/shooter/flywheel_controller.h"
+#include "y2020/control_loops/superstructure/superstructure_goal_generated.h"
+#include "y2020/control_loops/superstructure/superstructure_output_generated.h"
+#include "y2020/control_loops/superstructure/superstructure_position_generated.h"
+#include "y2020/control_loops/superstructure/superstructure_status_generated.h"
+
+namespace y2020 {
+namespace control_loops {
+namespace superstructure {
+namespace shooter {
+
+// Handles all flywheels together.
+class Shooter {
+ public:
+  Shooter();
+
+  flatbuffers::Offset<ShooterStatus> RunIteration(
+      const ShooterGoal *goal, const ShooterPosition *position,
+      flatbuffers::FlatBufferBuilder *fbb, OutputT *output);
+
+ private:
+  FlywheelController finisher_, accelerator_left_, accelerator_right_;
+
+  DISALLOW_COPY_AND_ASSIGN(Shooter);
+};
+
+}  // namespace shooter
+}  // namespace superstructure
+}  // namespace control_loops
+}  // namespace y2020
+
+#endif  // Y2020_CONTROL_LOOPS_SHOOTER_SHOOTER_H_
diff --git a/y2020/control_loops/superstructure/superstructure_goal.fbs b/y2020/control_loops/superstructure/superstructure_goal.fbs
index bade51e..f26b076 100644
--- a/y2020/control_loops/superstructure/superstructure_goal.fbs
+++ b/y2020/control_loops/superstructure/superstructure_goal.fbs
@@ -5,10 +5,10 @@
 table ShooterGoal {
   // Angular velocity in rad/s of the slowest (lowest) wheel in the kicker.
   // Positive is shooting the ball.
-  velocity_kicker:double;
+  velocity_accelerator:double;
 
   // Angular velocity in rad/s of the flywheel. Positive is shooting.
-  velocity_flywheel:double;
+  velocity_finisher:double;
 }
 
 table Goal {
diff --git a/y2020/control_loops/superstructure/superstructure_output.fbs b/y2020/control_loops/superstructure/superstructure_output.fbs
index c14c08f..2583106 100644
--- a/y2020/control_loops/superstructure/superstructure_output.fbs
+++ b/y2020/control_loops/superstructure/superstructure_output.fbs
@@ -23,11 +23,11 @@
   washing_machine_spinner_voltage:double;
 
   // Voltage sent to the kicker. Positive is shooting.
-  kicker_left_voltage:double;
-  kicker_right_voltage:double;
+  accelerator_left_voltage:double;
+  accelerator_right_voltage:double;
 
   // Voltage sent to the flywheel. Positive is shooting.
-  flywheel_voltage:double;
+  finisher_voltage:double;
 
   // Voltage sent to the motor driving the control panel. Positive is counterclockwise from above.
   control_panel_voltage:double;
diff --git a/y2020/control_loops/superstructure/superstructure_position.fbs b/y2020/control_loops/superstructure/superstructure_position.fbs
index 63f91c7..ed4ba18 100644
--- a/y2020/control_loops/superstructure/superstructure_position.fbs
+++ b/y2020/control_loops/superstructure/superstructure_position.fbs
@@ -4,12 +4,12 @@
 
 table ShooterPosition {
   // Flywheel angle in radians, positive is shooting.
-  theta_flywheel:double;
+  theta_finisher:double;
 
   // Kicker angle in radians of the slowest (lowest) wheel, positive is
   // accelerating the ball toward the shooter.
-  theta_kicker_left:double;
-  theta_kicker_right:double;
+  theta_accelerator_left:double;
+  theta_accelerator_right:double;
 }
 
 table Position {
diff --git a/y2020/control_loops/superstructure/superstructure_status.fbs b/y2020/control_loops/superstructure/superstructure_status.fbs
index 3dd2f2c..023a242 100644
--- a/y2020/control_loops/superstructure/superstructure_status.fbs
+++ b/y2020/control_loops/superstructure/superstructure_status.fbs
@@ -3,7 +3,7 @@
 
 namespace y2020.control_loops.superstructure;
 
-table ShooterSegmentStatus {
+table FlywheelControllerStatus {
   // The current average velocity in radians/second over the last kHistoryLength
   // in shooter.h
   avg_angular_velocity:double;
@@ -18,12 +18,12 @@
 
 table ShooterStatus {
   // The final wheel shooting the ball
-  flywheel:ShooterSegmentStatus;
+  finisher:FlywheelControllerStatus;
 
-  // The subsystem to accelerate the ball before the flywheel
+  // The subsystem to accelerate the ball before the finisher
   // Velocity is the slowest (lowest) wheel
-  kicker_left:ShooterSegmentStatus;
-  kicker_right:ShooterSegmentStatus;
+  accelerator_left:FlywheelControllerStatus;
+  accelerator_right:FlywheelControllerStatus;
 }
 
 table Status {