[wpilib][sim] Add Onboard IMU Sim (#8855)

This provides the ability to simulate parts of the Onboard IMU at the
HAL level. This allows team to use and simulate the IMU in code, and a
follow up PR could be made to the halsim_gui to add a new widget to view
and modify the data graphically.

Since the C++ IMU uses radians for angles that is what I did for the
simulator.

Partially deals with #8845

wpilibc/src/test/native/cpp/OnboardIMUTest.cpp

@@ -0,0 +1,59 @@
+// 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 "wpi/hardware/imu/OnboardIMU.hpp"
+
+#include <gtest/gtest.h>
+
+#include "wpi/simulation/OnboardIMUSim.hpp"
+
+using namespace wpi;
+
+TEST(OnboardIMUTest, SimDevices) {
+  OnboardIMU imu{OnboardIMU::FLAT};
+
+  EXPECT_EQ(0.0, imu.GetAngleX().value());
+  EXPECT_EQ(0.0, imu.GetAngleY().value());
+  EXPECT_EQ(0.0, imu.GetAngleZ().value());
+
+  EXPECT_EQ(0.0, imu.GetGyroRateX().value());
+  EXPECT_EQ(0.0, imu.GetGyroRateY().value());
+  EXPECT_EQ(0.0, imu.GetGyroRateZ().value());
+
+  EXPECT_EQ(0.0, imu.GetAccelX().value());
+  EXPECT_EQ(0.0, imu.GetAccelY().value());
+  EXPECT_EQ(0.0, imu.GetAccelZ().value());
+
+  EXPECT_EQ(0.0, imu.GetYaw().value());
+
+  sim::OnboardIMUSim sim{};
+
+  sim.SetAngleX(wpi::units::radian_t{1});
+  sim.SetAngleY(wpi::units::radian_t{2});
+  sim.SetAngleZ(wpi::units::radian_t{3});
+
+  sim.SetGyroRateX(wpi::units::radians_per_second_t{3.504});
+  sim.SetGyroRateY(wpi::units::radians_per_second_t{1.91});
+  sim.SetGyroRateZ(wpi::units::radians_per_second_t{22.9});
+
+  sim.SetAccelX(wpi::units::meters_per_second_squared_t{-1});
+  sim.SetAccelY(wpi::units::meters_per_second_squared_t{-2});
+  sim.SetAccelZ(wpi::units::meters_per_second_squared_t{-3});
+
+  sim.SetYaw(wpi::units::radian_t{1.234});
+
+  EXPECT_EQ(1.0, imu.GetAngleX().value());
+  EXPECT_EQ(2.0, imu.GetAngleY().value());
+  EXPECT_EQ(3.0, imu.GetAngleZ().value());
+
+  EXPECT_EQ(3.504, imu.GetGyroRateX().value());
+  EXPECT_EQ(1.91, imu.GetGyroRateY().value());
+  EXPECT_EQ(22.9, imu.GetGyroRateZ().value());
+
+  EXPECT_EQ(-1.0, imu.GetAccelX().value());
+  EXPECT_EQ(-2.0, imu.GetAccelY().value());
+  EXPECT_EQ(-3.0, imu.GetAccelZ().value());
+
+  EXPECT_EQ(1.234, imu.GetYaw().value());
+}

wpilibc/src/test/python/test_onboard_imu.py

@@ -0,0 +1,41 @@
+from wpilib import OnboardIMU
+from wpilib.simulation import OnboardIMUSim
+
+def test_sim_device() -> None:
+
+    imu = OnboardIMU(OnboardIMU.MountOrientation.FLAT)
+    sim = OnboardIMUSim()
+
+    assert 0.0 == imu.getAngleX()
+    assert 0.0 == imu.getAngleY()
+    assert 0.0 == imu.getAngleZ()
+    assert 0.0 == imu.getGyroRateX()
+    assert 0.0 == imu.getGyroRateY()
+    assert 0.0 == imu.getGyroRateZ()
+    assert 0.0 == imu.getAccelX()
+    assert 0.0 == imu.getAccelY()
+    assert 0.0 == imu.getAccelZ()
+    
+    sim.setAngleX(1)
+    sim.setAngleY(2)
+    sim.setAngleZ(3)
+    
+    sim.setGyroRateX(3.504)
+    sim.setGyroRateY(1.91)
+    sim.setGyroRateZ(22.9)
+    
+    sim.setAccelX(-1)
+    sim.setAccelY(-2)
+    sim.setAccelZ(-3)
+
+    assert 1.0 == imu.getAngleX()
+    assert 2.0 == imu.getAngleY()
+    assert 3.0 == imu.getAngleZ()
+
+    assert 3.504 == imu.getGyroRateX()
+    assert 1.91 == imu.getGyroRateY()
+    assert 22.9 == imu.getGyroRateZ()
+
+    assert -1.0 == imu.getAccelX()
+    assert -2.0 == imu.getAccelY()
+    assert -3.0 == imu.getAccelZ()