allwpilib/wpilibc/src/test/native/cpp/simulation/StateSpaceSimTest.cpp

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.

#include <gtest/gtest.h>

#include "wpi/hardware/motor/PWMVictorSPX.hpp"
#include "wpi/hardware/rotation/Encoder.hpp"
#include "wpi/math/controller/PIDController.hpp"
#include "wpi/math/controller/SimpleMotorFeedforward.hpp"
#include "wpi/math/system/plant/LinearSystemId.hpp"
#include "wpi/simulation/BatterySim.hpp"
#include "wpi/simulation/DifferentialDrivetrainSim.hpp"
#include "wpi/simulation/ElevatorSim.hpp"
#include "wpi/simulation/EncoderSim.hpp"
#include "wpi/simulation/FlywheelSim.hpp"
#include "wpi/simulation/LinearSystemSim.hpp"
#include "wpi/simulation/PWMSim.hpp"
#include "wpi/simulation/RoboRioSim.hpp"
#include "wpi/system/RobotController.hpp"
#include "wpi/units/angular_acceleration.hpp"
#include "wpi/units/angular_velocity.hpp"

TEST(StateSpaceSimTest, FlywheelSim) {
  const frc::LinearSystem<1, 1, 1> plant =
      frc::LinearSystemId::IdentifyVelocitySystem<units::radian>(
          0.02_V / 1_rad_per_s, 0.01_V / 1_rad_per_s_sq);
  frc::sim::FlywheelSim sim{plant, frc::DCMotor::NEO(2)};
  frc::PIDController controller{0.2, 0.0, 0.0};
  frc::SimpleMotorFeedforward<units::radian> feedforward{
      0_V, 0.02_V / 1_rad_per_s, 0.01_V / 1_rad_per_s_sq};
  frc::Encoder encoder{0, 1};
  frc::sim::EncoderSim encoderSim{encoder};
  frc::PWMVictorSPX motor{0};

  frc::sim::RoboRioSim::ResetData();
  encoderSim.ResetData();

  for (int i = 0; i < 100; i++) {
    // RobotPeriodic runs first
    auto voltageOut = controller.Calculate(encoder.GetRate(), 200.0);
    motor.SetVoltage(units::volt_t{voltageOut} +
                     feedforward.Calculate(200_rad_per_s));

    // Then, SimulationPeriodic runs
    frc::sim::RoboRioSim::SetVInVoltage(
        frc::sim::BatterySim::Calculate({sim.GetCurrentDraw()}));
    sim.SetInput(
        frc::Vectord<1>{motor.Get() * frc::RobotController::GetInputVoltage()});
    sim.Update(20_ms);
    encoderSim.SetRate(sim.GetAngularVelocity().value());
  }

  ASSERT_TRUE(std::abs(200 - encoder.GetRate()) < 0.1);
}