test_ompl_constraints.cpp

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/* Author: Jeroen De Maeyer */
 
#include "load_test_robot.h"
 
#include <memory>
#include <string>
#include <iostream>
 
#include <gtest/gtest.h>
#include <Eigen/Dense>
 
#include <moveit/robot_model/robot_model.h>
#include <moveit/robot_state/robot_state.h>
#include <moveit/robot_state/conversions.h>
#include <moveit/utils/robot_model_test_utils.h>
#include <moveit/ompl_interface/detail/ompl_constraints.h>
#include <moveit_msgs/msg/constraints.hpp>
#include <moveit/utils/logger.hpp>
 
#include <ompl/util/Exception.h>
#include <ompl/base/spaces/RealVectorStateSpace.h>
#include <ompl/base/spaces/constraint/ProjectedStateSpace.h>
#include <ompl/base/ConstrainedSpaceInformation.h>
 
rclcpp::Logger getLogger()
{
  return moveit::getLogger("test_ompl_constraints");
}
 
constexpr int NUM_RANDOM_TESTS = 10;
 
constexpr unsigned int DIFFERENT_LINK_OFFSET = 2;
 
constexpr double JAC_ERROR_TOLERANCE = 1e-4;
 
moveit_msgs::msg::PositionConstraint createPositionConstraint(std::string& base_link, std::string& ee_link)
{
  shape_msgs::msg::SolidPrimitive box_constraint;
  box_constraint.type = shape_msgs::msg::SolidPrimitive::BOX;
  box_constraint.dimensions = { 0.05, 0.4, 0.05 }; /* use -1 to indicate no constraints. */
 
  geometry_msgs::msg::Pose box_pose;
  box_pose.position.x = 0.9;
  box_pose.position.y = 0.0;
  box_pose.position.z = 0.2;
  box_pose.orientation.w = 1.0;
 
  moveit_msgs::msg::PositionConstraint position_constraint;
  position_constraint.header.frame_id = base_link;
  position_constraint.link_name = ee_link;
  position_constraint.constraint_region.primitives.push_back(box_constraint);
  position_constraint.constraint_region.primitive_poses.push_back(box_pose);
 
  return position_constraint;
}
 
class TestOMPLConstraints : public ompl_interface_testing::LoadTestRobot, public testing::Test
{
protected:
  TestOMPLConstraints(const std::string& robot_name, const std::string& group_name)
    : LoadTestRobot(robot_name, group_name)
  {
  }
 
  void SetUp() override
  {
  }
 
  void TearDown() override
  {
  }
 
  const Eigen::Isometry3d fk(const Eigen::VectorXd& q, const std::string& link_name) const
  {
    robot_state_->setJointGroupPositions(joint_model_group_, q);
    return robot_state_->getGlobalLinkTransform(link_name);
  }
 
  Eigen::VectorXd getRandomState()
  {
    robot_state_->setToRandomPositions(joint_model_group_);
    Eigen::VectorXd joint_positions;
    robot_state_->copyJointGroupPositions(joint_model_group_, joint_positions);
    return joint_positions;
  }
 
  Eigen::MatrixXd numericalJacobianPosition(const Eigen::VectorXd& q, const std::string& link_name) const
  {
    const double h = 1e-6; /* step size for numerical derivation */
 
    Eigen::MatrixXd jacobian = Eigen::MatrixXd::Zero(3, num_dofs_);
 
    // helper matrix for differentiation.
    Eigen::MatrixXd m_helper = h * Eigen::MatrixXd::Identity(num_dofs_, num_dofs_);
 
    for (std::size_t dim = 0; dim < num_dofs_; ++dim)
    {
      Eigen::Vector3d pos = fk(q, link_name).translation();
      Eigen::Vector3d pos_plus_h = fk(q + m_helper.col(dim), link_name).translation();
      Eigen::Vector3d col = (pos_plus_h - pos) / h;
      jacobian.col(dim) = col;
    }
    return jacobian;
  }
 
  void setPositionConstraints()
  {
    moveit_msgs::msg::Constraints constraint_msgs;
    constraint_msgs.position_constraints.push_back(createPositionConstraint(base_link_name_, ee_link_name_));
 
    constraint_ = std::make_shared<ompl_interface::BoxConstraint>(robot_model_, group_name_, num_dofs_);
    constraint_->init(constraint_msgs);
  }
 
  void setPositionConstraintsDifferentLink()
  {
    std::string different_link = joint_model_group_->getLinkModelNames().at(num_dofs_ - DIFFERENT_LINK_OFFSET);
 
    RCLCPP_DEBUG_STREAM(getLogger(), different_link);
 
    moveit_msgs::msg::Constraints constraint_msgs;
    constraint_msgs.position_constraints.push_back(createPositionConstraint(base_link_name_, different_link));
 
    constraint_ = std::make_shared<ompl_interface::BoxConstraint>(robot_model_, group_name_, num_dofs_);
    constraint_->init(constraint_msgs);
  }
 
  void setEqualityPositionConstraints()
  {
    moveit_msgs::msg::PositionConstraint pos_con_msg = createPositionConstraint(base_link_name_, ee_link_name_);
 
    // Make the tolerance on the x dimension smaller than the threshold used to recognize equality constraints.
    // (see docstring EqualityPositionConstraint::equality_constraint_threshold).
    pos_con_msg.constraint_region.primitives.at(0).dimensions[0] = 0.0005;
 
    // The unconstrained dimensions are set to a large (unused) value
    pos_con_msg.constraint_region.primitives.at(0).dimensions[1] = 1.0;
    pos_con_msg.constraint_region.primitives.at(0).dimensions[2] = 1.0;
 
    moveit_msgs::msg::Constraints constraint_msgs;
    constraint_msgs.position_constraints.push_back(pos_con_msg);
 
    // Tell the planner to use an Equality constraint model
    constraint_msgs.name = "use_equality_constraints";
 
    constraint_ = std::make_shared<ompl_interface::EqualityPositionConstraint>(robot_model_, group_name_, num_dofs_);
    constraint_->init(constraint_msgs);
  }
 
  void testJacobian()
  {
    SCOPED_TRACE("testJacobian");
 
    double total_error = 999.9;
 
    for (int i = 0; i < NUM_RANDOM_TESTS; ++i)
    {
      auto q = getRandomState();
      auto jac_exact = constraint_->calcErrorJacobian(q);
 
      Eigen::MatrixXd jac_approx = numericalJacobianPosition(q, constraint_->getLinkName());
 
      RCLCPP_DEBUG_STREAM(getLogger(), "Analytical jacobian:");
      RCLCPP_DEBUG_STREAM(getLogger(), jac_exact);
      RCLCPP_DEBUG_STREAM(getLogger(), "Finite difference jacobian:");
      RCLCPP_DEBUG_STREAM(getLogger(), jac_approx);
 
      total_error = (jac_exact - jac_approx).lpNorm<1>();
      EXPECT_LT(total_error, JAC_ERROR_TOLERANCE);
    }
  }
 
  void testOMPLProjectedStateSpaceConstruction()
  {
    SCOPED_TRACE("testOMPLProjectedStateSpaceConstruction");
 
    auto state_space = std::make_shared<ompl::base::RealVectorStateSpace>(num_dofs_);
    ompl::base::RealVectorBounds bounds(num_dofs_);
 
    // get joint limits from the joint model group
    auto joint_limits = joint_model_group_->getActiveJointModelsBounds();
    EXPECT_EQ(joint_limits.size(), num_dofs_);
 
    for (std::size_t i = 0; i < num_dofs_; ++i)
    {
      EXPECT_EQ(joint_limits[i]->size(), 1u);
      bounds.setLow(i, joint_limits[i]->at(0).min_position_);
      bounds.setHigh(i, joint_limits[i]->at(0).max_position_);
    }
 
    state_space->setBounds(bounds);
 
    auto constrained_state_space = std::make_shared<ompl::base::ProjectedStateSpace>(state_space, constraint_);
 
    // constrained_state_space->setStateSamplerAllocator()
 
    auto constrained_state_space_info =
        std::make_shared<ompl::base::ConstrainedSpaceInformation>(constrained_state_space);
 
    // TODO(jeroendm) There are some issue with the sanity checks.
    // But these issues do not prevent us to use the ConstrainedPlanningStateSpace! :)
    // The jacobian test is expected to fail because of the discontinuous constraint derivative.
    // In addition not all samples returned from the state sampler will be valid.
    // For more details: https://github.com/ros-planning/moveit/issues/2092#issuecomment-669911722
    try
    {
      constrained_state_space->sanityChecks();
    }
    catch (ompl::Exception& ex)
    {
      RCLCPP_ERROR(getLogger(), "Sanity checks did not pass: %s", ex.what());
    }
  }
 
  void testEqualityPositionConstraints()
  {
    SCOPED_TRACE("testEqualityPositionConstraints");
 
    EXPECT_NE(constraint_, nullptr) << "First call setEqualityPositionConstraints before calling this test.";
 
    // all test below are in the assumption that we have equality constraints on the x-position, dimension 0.
 
    Eigen::VectorXd joint_values = getDeterministicState();
 
    Eigen::Vector3d f;
    f << 99, 99, 99;  // fill in known but wrong values that should all be overwritten
    constraint_->function(joint_values, f);
 
    // f should always be zero for unconstrained dimensions
    EXPECT_DOUBLE_EQ(f[1], 0.0);
    EXPECT_DOUBLE_EQ(f[2], 0.0);
 
    Eigen::MatrixXd jac(3, num_dofs_);
    jac.setOnes();  // fill in known but wrong values that should all be overwritten
    constraint_->jacobian(joint_values, jac);
 
    for (std::size_t i = 0; i < num_dofs_; ++i)
    {
      // rows for unconstrained dimensions should always be zero
      EXPECT_DOUBLE_EQ(jac(1, i), 0.0);
      EXPECT_DOUBLE_EQ(jac(2, i), 0.0);
    }
    // the constrained x-dimension has some non-zeros
    // ( we checked this is true for the given joint values!)
    EXPECT_NE(f[0], 0.0);
    EXPECT_NE(jac.row(0).squaredNorm(), 0.0);
  }
 
protected:
  std::shared_ptr<ompl_interface::BaseConstraint> constraint_;
};
 
/***************************************************************************
 * Run all tests on the Panda robot
 * ************************************************************************/
class PandaConstraintTest : public TestOMPLConstraints
{
protected:
  PandaConstraintTest() : TestOMPLConstraints("panda", "panda_arm")
  {
  }
};
 
TEST_F(PandaConstraintTest, InitPositionConstraint)
{
  setPositionConstraints();
  setPositionConstraintsDifferentLink();
}
 
TEST_F(PandaConstraintTest, PositionConstraintJacobian)
{
  setPositionConstraints();
  testJacobian();
 
  constraint_.reset();
  setPositionConstraintsDifferentLink();
  testJacobian();
}
 
TEST_F(PandaConstraintTest, PositionConstraintOMPLCheck)
{
  setPositionConstraints();
  testOMPLProjectedStateSpaceConstruction();
  // testOMPLStateSampler();
 
  constraint_.reset();
  setPositionConstraintsDifferentLink();
  testOMPLProjectedStateSpaceConstruction();
}
 
TEST_F(PandaConstraintTest, EqualityPositionConstraints)
{
  setEqualityPositionConstraints();
  testOMPLProjectedStateSpaceConstruction();
  testEqualityPositionConstraints();
}
/***************************************************************************
 * Run all tests on the Fanuc robot
 * ************************************************************************/
class FanucConstraintTest : public TestOMPLConstraints
{
protected:
  FanucConstraintTest() : TestOMPLConstraints("fanuc", "manipulator")
  {
  }
};
 
TEST_F(FanucConstraintTest, InitPositionConstraint)
{
  setPositionConstraints();
  setPositionConstraintsDifferentLink();
}
 
TEST_F(FanucConstraintTest, PositionConstraintJacobian)
{
  setPositionConstraints();
  testJacobian();
 
  constraint_.reset();
  setPositionConstraintsDifferentLink();
  testJacobian();
}
 
TEST_F(FanucConstraintTest, PositionConstraintOMPLCheck)
{
  setPositionConstraints();
  testOMPLProjectedStateSpaceConstruction();
  // testOMPLStateSampler();
 
  constraint_.reset();
  setPositionConstraintsDifferentLink();
  testOMPLProjectedStateSpaceConstruction();
}
 
TEST_F(FanucConstraintTest, EqualityPositionConstraints)
{
  setEqualityPositionConstraints();
  testOMPLProjectedStateSpaceConstruction();
  testEqualityPositionConstraints();
}
 
/***************************************************************************
 * Run all tests on the PR2's left arm
 * ************************************************************************/
class PR2LeftArmConstraintTest : public TestOMPLConstraints
{
protected:
  PR2LeftArmConstraintTest() : TestOMPLConstraints("pr2", "left_arm")
  {
  }
};
 
TEST_F(PR2LeftArmConstraintTest, InitPositionConstraint)
{
  setPositionConstraints();
  setPositionConstraintsDifferentLink();
}
 
TEST_F(PR2LeftArmConstraintTest, PositionConstraintJacobian)
{
  setPositionConstraints();
  testJacobian();
 
  constraint_.reset();
  setPositionConstraintsDifferentLink();
  testJacobian();
}
 
TEST_F(PR2LeftArmConstraintTest, PositionConstraintOMPLCheck)
{
  setPositionConstraints();
  testOMPLProjectedStateSpaceConstruction();
 
  constraint_.reset();
  setPositionConstraintsDifferentLink();
  testOMPLProjectedStateSpaceConstruction();
}
 
TEST_F(PR2LeftArmConstraintTest, EqualityPositionConstraints)
{
  setEqualityPositionConstraints();
  testOMPLProjectedStateSpaceConstruction();
  testEqualityPositionConstraints();
}
 
/***************************************************************************
 * MAIN
 * ************************************************************************/
int main(int argc, char** argv)
{
  testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}