pxmlw6n2f/Gazebo_Distributed_TCP/test/integration/physics_msgs_inertia.cc

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2019-03-28 10:57:49 +08:00
/*
* Copyright (C) 2015 Open Source Robotics Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <string>
#include "gazebo/msgs/msgs.hh"
#include "gazebo/physics/physics.hh"
#include "gazebo/transport/transport.hh"
#include "gazebo/test/ServerFixture.hh"
#include "gazebo/test/helper_physics_generator.hh"
using namespace gazebo;
class InertiaMsgsTest : public ServerFixture,
public testing::WithParamInterface<const char*>
{
/// \brief Set inertia parameters over ~/model/modify
/// and verify that Inertial accessors register the change.
/// \param[in] _physicsEngine Type of physics engine to use.
public: void InertialAccessors(const std::string &_physicsEngine);
/// \brief Set center of mass of link over ~/model/modify
/// and verify that it causes a seesaw to unbalance.
/// \param[in] _physicsEngine Type of physics engine to use.
public: void SetCoG(const std::string &_physicsEngine);
/// \brief Set mass of link over ~/model/modify
/// and verify that it causes a seesaw to unbalance.
/// \param[in] _physicsEngine Type of physics engine to use.
public: void SetMass(const std::string &_physicsEngine);
/// \brief Set moment of inertia of pendulums over ~/model/modify
/// and verify that it changes frequency of oscillation.
/// \param[in] _physicsEngine Type of physics engine to use.
public: void SetPendulumInertia(const std::string &_physicsEngine);
};
/////////////////////////////////////////////////
void InertiaMsgsTest::InertialAccessors(const std::string &_physicsEngine)
{
this->Load("worlds/seesaw.world", true, _physicsEngine);
physics::WorldPtr world = physics::get_world("default");
ASSERT_TRUE(world != NULL);
const std::string modelName("cube1");
auto model = world->GetModel(modelName);
ASSERT_TRUE(model != NULL);
auto link = model->GetLink();
ASSERT_TRUE(link != NULL);
auto inertial = link->GetInertial();
ASSERT_TRUE(inertial != NULL);
const double mass = inertial->GetMass();
const math::Vector3 cog = inertial->GetCoG();
const math::Vector3 Ixxyyzz = inertial->GetPrincipalMoments();
const math::Vector3 Ixyxzyz = inertial->GetProductsofInertia();
EXPECT_DOUBLE_EQ(mass, 45.56250000000001);
EXPECT_EQ(cog, math::Vector3::Zero);
EXPECT_EQ(Ixxyyzz, 1.537734375*math::Vector3::One);
EXPECT_EQ(Ixyxzyz, math::Vector3::Zero);
// new inertial values
msgs::Model msg;
msg.set_name(modelName);
msg.add_link();
auto msgLink = msg.mutable_link(0);
msgLink->set_name("link");
msgLink->set_id(link->GetId());
auto msgInertial = msgLink->mutable_inertial();
msgInertial->set_mass(99.9);
msgInertial->set_ixx(12.3);
msgInertial->set_ixy(0.123);
msgInertial->set_ixz(0.456);
msgInertial->set_iyy(13.4);
msgInertial->set_iyz(0.789);
msgInertial->set_izz(15.6);
const ignition::math::Vector3d newCog(1.1, -2.2, 3.3);
msgs::Set(msgInertial->mutable_pose(), ignition::math::Pose3d(
newCog, ignition::math::Quaterniond()));
// Set inertial properties by publishing to "~/model/modify"
transport::PublisherPtr modelPub =
this->node->Advertise<msgs::Model>("~/model/modify");
modelPub->WaitForConnection();
modelPub->Publish(msg, true);
while (newCog != inertial->GetCoG().Ign())
{
world->Step(1);
common::Time::MSleep(1);
modelPub->Publish(msg, true);
}
EXPECT_DOUBLE_EQ(inertial->GetMass(), msgInertial->mass());
EXPECT_EQ(inertial->GetCoG().Ign(), newCog);
EXPECT_EQ(inertial->GetPrincipalMoments(),
ignition::math::Vector3d(
msgInertial->ixx(),
msgInertial->iyy(),
msgInertial->izz()));
EXPECT_EQ(inertial->GetProductsofInertia(),
ignition::math::Vector3d(
msgInertial->ixy(),
msgInertial->ixz(),
msgInertial->iyz()));
}
/////////////////////////////////////////////////
TEST_P(InertiaMsgsTest, InertialAccessors)
{
InertialAccessors(GetParam());
}
/////////////////////////////////////////////////
void InertiaMsgsTest::SetCoG(const std::string &_physicsEngine)
{
this->Load("worlds/seesaw.world", true, _physicsEngine);
physics::WorldPtr world = physics::get_world("default");
ASSERT_TRUE(world != NULL);
// check the gravity vector
physics::PhysicsEnginePtr physics = world->GetPhysicsEngine();
ASSERT_TRUE(physics != NULL);
EXPECT_EQ(physics->GetType(), _physicsEngine);
math::Vector3 g = physics->GetGravity();
EXPECT_EQ(g, math::Vector3(0, 0, -9.8));
const std::string modelName("plank");
auto model = world->GetModel(modelName);
ASSERT_TRUE(model != NULL);
auto link = model->GetLink();
ASSERT_TRUE(link != NULL);
auto inertial = link->GetInertial();
ASSERT_TRUE(inertial != NULL);
const double mass = inertial->GetMass();
const math::Vector3 cog = inertial->GetCoG();
const math::Vector3 Ixxyyzz = inertial->GetPrincipalMoments();
const math::Vector3 Ixyxzyz = inertial->GetProductsofInertia();
EXPECT_DOUBLE_EQ(mass, 120);
EXPECT_EQ(cog, math::Vector3::Zero);
EXPECT_EQ(Ixxyyzz, math::Vector3(2.564, 360.064, 362.5));
EXPECT_EQ(Ixyxzyz, math::Vector3::Zero);
// new center of mass
msgs::Model msg;
msg.set_name(modelName);
msg.add_link();
auto msgLink = msg.mutable_link(0);
msgLink->set_name("link");
msgLink->set_id(link->GetId());
auto msgInertial = msgLink->mutable_inertial();
const ignition::math::Vector3d newCoG(2.5, 0, 0);
msgs::Set(msgInertial->mutable_pose(), ignition::math::Pose3d(
newCoG, ignition::math::Quaterniond()));
// Set inertial properties by publishing to "~/model/modify"
transport::PublisherPtr modelPub =
this->node->Advertise<msgs::Model>("~/model/modify");
modelPub->WaitForConnection();
modelPub->Publish(msg, true);
while (newCoG != inertial->GetCoG().Ign())
{
world->Step(1);
common::Time::MSleep(1);
modelPub->Publish(msg, true);
}
EXPECT_EQ(inertial->GetCoG().Ign(), newCoG);
world->Step(1000);
EXPECT_GT(model->GetWorldPose().rot.GetAsEuler().y, 0.25);
}
/////////////////////////////////////////////////
TEST_P(InertiaMsgsTest, SetCoG)
{
std::string physicsEngine = GetParam();
if (physicsEngine == "bullet" || physicsEngine == "simbody")
{
gzerr << physicsEngine
<< " doesn't yet support dynamically changing a link's center of mass"
<< std::endl;
return;
}
SetCoG(GetParam());
}
/////////////////////////////////////////////////
void InertiaMsgsTest::SetMass(const std::string &_physicsEngine)
{
this->Load("worlds/seesaw.world", true, _physicsEngine);
physics::WorldPtr world = physics::get_world("default");
ASSERT_TRUE(world != NULL);
// check the gravity vector
physics::PhysicsEnginePtr physics = world->GetPhysicsEngine();
ASSERT_TRUE(physics != NULL);
EXPECT_EQ(physics->GetType(), _physicsEngine);
math::Vector3 g = physics->GetGravity();
EXPECT_EQ(g, math::Vector3(0, 0, -9.8));
const std::string modelName("cube1");
auto model = world->GetModel(modelName);
ASSERT_TRUE(model != NULL);
auto link = model->GetLink();
ASSERT_TRUE(link != NULL);
auto inertial = link->GetInertial();
ASSERT_TRUE(inertial != NULL);
const double mass = inertial->GetMass();
const math::Vector3 cog = inertial->GetCoG();
const math::Vector3 Ixxyyzz = inertial->GetPrincipalMoments();
const math::Vector3 Ixyxzyz = inertial->GetProductsofInertia();
EXPECT_DOUBLE_EQ(mass, 45.56250000000001);
EXPECT_EQ(cog, math::Vector3::Zero);
EXPECT_EQ(Ixxyyzz, 1.537734375*math::Vector3::One);
EXPECT_EQ(Ixyxzyz, math::Vector3::Zero);
// new inertial values
msgs::Model msg;
msg.set_name(modelName);
msg.add_link();
auto msgLink = msg.mutable_link(0);
msgLink->set_name("link");
msgLink->set_id(link->GetId());
auto msgInertial = msgLink->mutable_inertial();
const double newMass = 500;
msgInertial->set_mass(newMass);
// Set inertial properties by publishing to "~/model/modify"
transport::PublisherPtr modelPub =
this->node->Advertise<msgs::Model>("~/model/modify");
modelPub->WaitForConnection();
modelPub->Publish(msg, true);
while (!math::equal(newMass, inertial->GetMass()))
{
world->Step(1);
common::Time::MSleep(1);
modelPub->Publish(msg, true);
}
EXPECT_DOUBLE_EQ(inertial->GetMass(), msgInertial->mass());
world->Step(1000);
EXPECT_LT(model->GetWorldPose().pos.z, 0.40);
}
/////////////////////////////////////////////////
TEST_P(InertiaMsgsTest, SetMass)
{
std::string physicsEngine = GetParam();
if (physicsEngine == "simbody")
{
gzerr << physicsEngine
<< " doesn't yet support dynamically changing a link's mass"
<< std::endl;
return;
}
SetMass(physicsEngine);
}
/////////////////////////////////////////////////
void InertiaMsgsTest::SetPendulumInertia(const std::string &_physicsEngine)
{
this->Load("worlds/pendulum_axes.world", true, _physicsEngine);
physics::WorldPtr world = physics::get_world("default");
ASSERT_TRUE(world != NULL);
// check the gravity vector
physics::PhysicsEnginePtr physics = world->GetPhysicsEngine();
ASSERT_TRUE(physics != NULL);
EXPECT_EQ(physics->GetType(), _physicsEngine);
math::Vector3 g = physics->GetGravity();
EXPECT_EQ(g, math::Vector3(0, 0, -9.8));
double dt = physics->GetMaxStepSize();
EXPECT_NEAR(dt, 1e-3, 1e-6);
std::vector<std::string> modelNames;
for (auto const &model : world->GetModels())
{
std::string name = model->GetName();
if (name.find("pendulum_") == 0)
{
modelNames.push_back(name);
}
}
ASSERT_EQ(modelNames.size(), 6u);
std::vector<physics::ModelPtr> models;
std::vector<physics::JointPtr> joints;
std::vector<physics::LinkPtr> links;
std::vector<double> pendulumLengths;
std::vector<double> initialAngles;
std::vector<double> cycleAngles;
std::vector<int> cycleCount;
for (auto const &modelName : modelNames)
{
gzdbg << "Initializing model "
<< modelName
<< std::endl;
auto model = world->GetModel(modelName);
ASSERT_TRUE(model != NULL);
models.push_back(model);
auto link = model->GetLink();
ASSERT_TRUE(link != NULL);
links.push_back(link);
auto joint = model->GetJoint("joint");
ASSERT_TRUE(joint != NULL);
joints.push_back(joint);
// Compute distance from cg to joint anchor
auto linkPose = link->GetWorldCoGPose();
auto jointPose = joint->GetWorldPose();
auto jointToCoG = linkPose.pos - jointPose.pos;
double length = jointToCoG.GetLength();
EXPECT_NEAR(length, 0.05, 1e-6);
pendulumLengths.push_back(length);
double angle =
asin(jointToCoG.Cross(g).Dot(joint->GetGlobalAxis(0)) / length / 9.8);
EXPECT_NEAR(angle, -M_PI / 10, 1e-5);
initialAngles.push_back(angle);
// hysteresis threshhold for cycle counting
cycleAngles.push_back(angle / 2);
// count of oscillation cycles
cycleCount.push_back(0);
}
// unthrottle physics to allow for many timesteps
physics->SetRealTimeUpdateRate(0.0);
// simulate 30 seconds and count oscillation cycles
const int steps = 30000;
const double timeStepped = steps * dt;
for (int step = 0; step < steps; ++step)
{
world->Step(1);
for (unsigned int i = 0; i < models.size(); ++i)
{
auto model = models[i];
auto joint = joints[i];
auto initialAngle = initialAngles[i];
auto cycleAngle = cycleAngles[i];
auto angle = joint->GetAngle(0).Radian() - initialAngle;
if (angle / cycleAngle >= 1)
{
cycleAngles[i] *= -1;
cycleCount[i]++;
}
}
}
// Verify that expected number of cycles is counted
for (unsigned int i = 0; i < models.size(); ++i)
{
auto length = pendulumLengths[i];
auto cycles = cycleCount[i];
// expected natural frequency for box pendulum (Hz)
// see physics_msgs_inertia.ipynb for derivation
double freq = 0.5 * M_1_PI * sqrt(300.0 / 401.0 * g.GetLength() / length);
// 2 cycles counted per oscillation
double expectedCycles = 2 * freq * timeStepped;
EXPECT_EQ(cycles, static_cast<int>(expectedCycles));
}
// modify inertia of each named pendulum
for (unsigned int i = 0; i < models.size(); ++i)
{
auto model = models[i];
auto joint = joints[i];
auto link = links[i];
auto inertial = link->GetInertial();
ASSERT_TRUE(inertial != NULL);
const math::Vector3 Ixxyyzz = inertial->GetPrincipalMoments();
const math::Vector3 Ixyxzyz = inertial->GetProductsofInertia();
// new inertial values
msgs::Model msg;
msg.set_name(modelNames[i]);
msg.add_link();
auto msgLink = msg.mutable_link(0);
msgLink->set_name("link");
msgLink->set_id(link->GetId());
auto msgInertial = msgLink->mutable_inertial();
msgInertial->set_ixx(Ixxyyzz[0] * 2);
msgInertial->set_iyy(Ixxyyzz[1] * 2);
msgInertial->set_izz(Ixxyyzz[2] * 2);
// Set inertial properties by publishing to "~/model/modify"
transport::PublisherPtr modelPub =
this->node->Advertise<msgs::Model>("~/model/modify");
modelPub->WaitForConnection();
modelPub->Publish(msg, true);
while (Ixxyyzz[0] == inertial->GetPrincipalMoments()[0])
{
world->Step(1);
common::Time::MSleep(1);
modelPub->Publish(msg, true);
}
EXPECT_NEAR(2*Ixxyyzz[0], inertial->GetPrincipalMoments()[0], 1e-10);
EXPECT_NEAR(2*Ixxyyzz[1], inertial->GetPrincipalMoments()[1], 1e-10);
EXPECT_NEAR(2*Ixxyyzz[2], inertial->GetPrincipalMoments()[2], 1e-10);
}
// Reset world and cycle count to restore initial conditions
world->Reset();
for (unsigned int i = 0; i < cycleCount.size(); ++i)
{
cycleCount[i] = 0;
cycleAngles[i] = initialAngles[i] / 2;
}
// simulate 30 seconds and count oscillation cycles
for (int step = 0; step < steps; ++step)
{
world->Step(1);
for (unsigned int i = 0; i < models.size(); ++i)
{
auto model = models[i];
auto joint = joints[i];
auto initialAngle = initialAngles[i];
auto cycleAngle = cycleAngles[i];
auto angle = joint->GetAngle(0).Radian() - initialAngle;
if (angle / cycleAngle >= 1)
{
cycleAngles[i] *= -1;
cycleCount[i]++;
}
}
}
// Verify that expected number of cycles is counted
for (unsigned int i = 0; i < models.size(); ++i)
{
auto length = pendulumLengths[i];
auto cycles = cycleCount[i];
// expected natural frequency for box pendulum (Hz)
// see physics_msgs_inertia.ipynb for derivation
double freq = 0.5 * M_1_PI * sqrt(150.0 / 251.0 * g.GetLength() / length);
// 2 cycles counted per oscillation
double expectedCycles = 2 * freq * timeStepped;
EXPECT_EQ(cycles, static_cast<int>(expectedCycles));
}
}
/////////////////////////////////////////////////
TEST_P(InertiaMsgsTest, SetPendulumInertia)
{
std::string physicsEngine = GetParam();
if (physicsEngine == "simbody")
{
gzerr << physicsEngine
<< " doesn't yet support dynamically changing moment of inertia"
<< std::endl;
return;
}
SetPendulumInertia(physicsEngine);
}
INSTANTIATE_TEST_CASE_P(PhysicsEngines, InertiaMsgsTest,
PHYSICS_ENGINE_VALUES);
/////////////////////////////////////////////////
int main(int argc, char **argv)
{
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}