Add kinematics suite (#1787)

Co-authored-by: Tyler Veness <calcmogul@gmail.com>
Co-authored-by: Matt <matthew.morley.ca@gmail.com>

wpilibcExamples/src/main/cpp/examples/SwerveBot/include/Drivetrain.h

@@ -0,0 +1,61 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <frc/AnalogGyro.h>
+#include <frc/geometry/Translation2d.h>
+#include <frc/kinematics/SwerveDriveKinematics.h>
+#include <frc/kinematics/SwerveDriveOdometry.h>
+#include <wpi/math>
+
+#include "SwerveModule.h"
+
+/**
+ * Represents a swerve drive style drivetrain.
+ */
+class Drivetrain {
+ public:
+  Drivetrain() { m_gyro.Reset(); }
+
+  /**
+   * Get the robot angle as a Rotation2d.
+   */
+  frc::Rotation2d GetAngle() const {
+    // Negating the angle because WPILib Gyros are CW positive.
+    return frc::Rotation2d(units::degree_t(-m_gyro.GetAngle()));
+  }
+
+  void Drive(units::meters_per_second_t xSpeed,
+             units::meters_per_second_t ySpeed, units::radians_per_second_t rot,
+             bool fieldRelative);
+  void UpdateOdometry();
+
+  static constexpr units::meters_per_second_t kMaxSpeed =
+      3.0_mps;  // 3 meters per second
+  static constexpr units::radians_per_second_t kMaxAngularSpeed{
+      wpi::math::pi};  // 1/2 rotation per second
+
+ private:
+  frc::Translation2d m_frontLeftLocation{+0.381_m, +0.381_m};
+  frc::Translation2d m_frontRightLocation{+0.381_m, -0.381_m};
+  frc::Translation2d m_backLeftLocation{-0.381_m, +0.381_m};
+  frc::Translation2d m_backRightLocation{-0.381_m, -0.381_m};
+
+  SwerveModule m_frontLeft{1, 2};
+  SwerveModule m_frontRight{2, 3};
+  SwerveModule m_backLeft{5, 6};
+  SwerveModule m_backRight{7, 8};
+
+  frc::AnalogGyro m_gyro{0};
+
+  frc::SwerveDriveKinematics<4> m_kinematics{
+      m_frontLeftLocation, m_frontRightLocation, m_backLeftLocation,
+      m_backRightLocation};
+
+  frc::SwerveDriveOdometry<4> m_odometry{m_kinematics};
+};

wpilibcExamples/src/main/cpp/examples/SwerveBot/include/SwerveModule.h

@@ -0,0 +1,49 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <frc/Encoder.h>
+#include <frc/Spark.h>
+#include <frc/controller/PIDController.h>
+#include <frc/controller/ProfiledPIDController.h>
+#include <frc/kinematics/SwerveModuleState.h>
+#include <wpi/math>
+
+class SwerveModule {
+ public:
+  SwerveModule(int driveMotorChannel, int turningMotorChannel);
+  frc::SwerveModuleState GetState() const;
+  void SetDesiredState(const frc::SwerveModuleState& state);
+
+ private:
+  static constexpr double kWheelRadius = 0.0508;
+  static constexpr int kEncoderResolution = 4096;
+
+  // We have to use meters here instead of radians because of the fact that
+  // ProfiledPIDController's constraints only take in meters per second and
+  // meters per second squared.
+
+  static constexpr units::meters_per_second_t kModuleMaxAngularVelocity =
+      units::meters_per_second_t(wpi::math::pi);  // radians per second
+  static constexpr units::meters_per_second_squared_t
+      kModuleMaxAngularAcceleration = units::meters_per_second_squared_t(
+          wpi::math::pi * 2.0);  // radians per second squared
+
+  frc::Spark m_driveMotor;
+  frc::Spark m_turningMotor;
+
+  frc::Encoder m_driveEncoder{0, 1};
+  frc::Encoder m_turningEncoder{0, 1};
+
+  frc2::PIDController m_drivePIDController{1.0, 0, 0};
+  frc::ProfiledPIDController m_turningPIDController{
+      1.0,
+      0.0,
+      0.0,
+      {kModuleMaxAngularVelocity, kModuleMaxAngularAcceleration}};
+};