test_filter.cpp

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#include <cmath>
#include <cstddef>

#include <trajectory_tracker/filter.h>

#include <gtest/gtest.h>

TEST(Filter, LPFCharacteristic)
{
  for (int time_const = 20; time_const < 100; time_const += 20)
  {
    trajectory_tracker::Filter lpf(trajectory_tracker::Filter::FILTER_LPF, time_const, 0.0);
    ASSERT_LT(std::abs(lpf.get()), 1e-6);

    // Input step function
    float ret = 0;
    for (int i = 0; i < time_const; ++i)
    {
      ret = lpf.in(1.0);
    }
    // Check value at 1 time unit
    ASSERT_TRUE(ret == lpf.get());
    ASSERT_LT(std::abs(ret - (1.0 - expf(-1.0))), 1e-2);

    for (int i = time_const; i < time_const * 100; ++i)
    {
      ret = lpf.in(1.0);
    }
    // Check value at inf time
    ASSERT_TRUE(ret == lpf.get());
    ASSERT_LT(std::abs(ret - 1.0), 1e-2);

    // Check set
    lpf.set(1.0);
    ASSERT_LT(std::abs(lpf.get() - 1.0), 1e-2);
    lpf.in(1.0);
    ASSERT_LT(std::abs(lpf.get() - 1.0), 1e-2);
  }
}

TEST(Filter, HPFCharacteristic)
{
  for (int time_const = 20; time_const < 100; time_const += 20)
  {
    trajectory_tracker::Filter lpf(trajectory_tracker::Filter::FILTER_LPF, time_const, 0.0);
    trajectory_tracker::Filter hpf(trajectory_tracker::Filter::FILTER_HPF, time_const, 0.0);

    // Input step function
    for (int i = 0; i < time_const * 10; ++i)
    {
      float ret_h, ret_l;
      ret_l = lpf.in(1.0);
      ret_h = hpf.in(1.0);

      // Check complementarity against LPF
      ASSERT_LT(std::abs(ret_l + ret_h - 1.0), 1e-2);
    }
  }
}

TEST(Filter, AugleLPF)
{
  for (float zero = 0.0; zero < M_PI * 2 * 4; zero += M_PI * 2)
  {
    // Check 0.5 rad to 2pi - 0.5 rad transition
    const float start1 = zero + 0.5;
    const float end1 = zero + M_PI * 2.0 - 0.5;

    trajectory_tracker::Filter lpf(trajectory_tracker::Filter::FILTER_LPF, 10, start1);
    trajectory_tracker::Filter lpf_angle(trajectory_tracker::Filter::FILTER_LPF, 10, start1, true);
    ASSERT_LT(std::abs(lpf.get() - start1), 1e-6);
    ASSERT_LT(std::abs(lpf_angle.get() - start1), 1e-6);

    for (int i = 0; i < 100; ++i)
    {
      lpf.in(end1);
      lpf_angle.in(end1);
      ASSERT_GT(lpf.get(), start1);
      ASSERT_LT(lpf_angle.get(), start1);
    }
    ASSERT_LT(std::abs(lpf.get() - end1), 1e-2);
    ASSERT_LT(std::abs(lpf_angle.get() - (zero - 0.5)), 1e-2);

    // Check 2pi - 0.5 to 0.5 rad transition
    const float start2 = zero - 0.5;
    const float end2 = zero - M_PI * 2.0 + 0.5;

    lpf.set(start2);
    lpf_angle.set(start2);
    ASSERT_LT(std::abs(lpf.get() - start2), 1e-6);
    ASSERT_LT(std::abs(lpf_angle.get() - start2), 1e-6);

    for (int i = 0; i < 100; ++i)
    {
      lpf.in(end2);
      lpf_angle.in(end2);
      ASSERT_LT(lpf.get(), start2);
      ASSERT_GT(lpf_angle.get(), start2);
    }
    ASSERT_LT(std::abs(lpf.get() - end2), 1e-2);
    ASSERT_LT(std::abs(lpf_angle.get() - (zero + 0.5)), 1e-2);
  }
}

int main(int argc, char** argv)
{
  testing::InitGoogleTest(&argc, argv);

  return RUN_ALL_TESTS();
}