概述
Moveit使用运动规划插件来进行在线的运动规划。下例展示了调用运动规划器的过程。
示例代码
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/* Author: Sachin Chitta, Michael Lautman */
#include <pluginlib/class_loader.h>
#include <ros/ros.h>
// MoveIt
#include <moveit/robot_model_loader/robot_model_loader.h>
#include <moveit/planning_interface/planning_interface.h>
#include <moveit/planning_scene/planning_scene.h>
#include <moveit/kinematic_constraints/utils.h>
#include <moveit_msgs/DisplayTrajectory.h>
#include <moveit_msgs/PlanningScene.h>
#include <moveit_visual_tools/moveit_visual_tools.h>
#include <boost/scoped_ptr.hpp>
int main(int argc, char** argv)
{
const std::string node_name = "motion_planning_tutorial";
ros::init(argc, argv, node_name);
ros::AsyncSpinner spinner(1);
spinner.start();
ros::NodeHandle node_handle("~");
// BEGIN_TUTORIAL
// Start
// ^^^^^
// Setting up to start using a planner is pretty easy. Planners are
// setup as plugins in MoveIt and you can use the ROS pluginlib
// interface to load any planner that you want to use. Before we
// can load the planner, we need two objects, a RobotModel and a
// PlanningScene. We will start by instantiating a `RobotModelLoader`_
// object, which will look up the robot description on the ROS
// parameter server and construct a :moveit_core:`RobotModel` for us
// to use.
//
// .. _RobotModelLoader:
// http://docs.ros.org/melodic/api/moveit_ros_planning/html/classrobot__model__loader_1_1RobotModelLoader.html
const std::string PLANNING_GROUP = "panda_arm";
robot_model_loader::RobotModelLoader robot_model_loader("robot_description");
robot_model::RobotModelPtr robot_model = robot_model_loader.getModel();
/* Create a RobotState and JointModelGroup to keep track of the current robot pose and planning group*/
robot_state::RobotStatePtr robot_state(new robot_state::RobotState(robot_model));
const robot_state::JointModelGroup* joint_model_group = robot_state->getJointModelGroup(PLANNING_GROUP);
// Using the :moveit_core:`RobotModel`, we can construct a :planning_scene:`PlanningScene`
// that maintains the state of the world (including the robot).
planning_scene::PlanningScenePtr planning_scene(new planning_scene::PlanningScene(robot_model));
// Configure a valid robot state
planning_scene->getCurrentStateNonConst().setToDefaultValues(joint_model_group, "ready");
// We will now construct a loader to load a planner, by name.
// Note that we are using the ROS pluginlib library here.
boost::scoped_ptr<pluginlib::ClassLoader<planning_interface::PlannerManager>> planner_plugin_loader;
planning_interface::PlannerManagerPtr planner_instance;
std::string planner_plugin_name;
// We will get the name of planning plugin we want to load
// from the ROS parameter server, and then load the planner
// making sure to catch all exceptions.
if (!node_handle.getParam("planning_plugin", planner_plugin_name))
ROS_FATAL_STREAM("Could not find planner plugin name");
try
{
planner_plugin_loader.reset(new pluginlib::ClassLoader<planning_interface::PlannerManager>(
"moveit_core", "planning_interface::PlannerManager"));
}
catch (pluginlib::PluginlibException& ex)
{
ROS_FATAL_STREAM("Exception while creating planning plugin loader " << ex.what());
}
try
{
planner_instance.reset(planner_plugin_loader->createUnmanagedInstance(planner_plugin_name));
if (!planner_instance->initialize(robot_model, node_handle.getNamespace()))
ROS_FATAL_STREAM("Could not initialize planner instance");
ROS_INFO_STREAM("Using planning interface '" << planner_instance->getDescription() << "'");
}
catch (pluginlib::PluginlibException& ex)
{
const std::vector<std::string>& classes = planner_plugin_loader->getDeclaredClasses();
std::stringstream ss;
for (std::size_t i = 0; i < classes.size(); ++i)
ss << classes[i] << " ";
ROS_ERROR_STREAM("Exception while loading planner '" << planner_plugin_name << "': " << ex.what() << std::endl
<< "Available plugins: " << ss.str());
}
// Visualization
// ^^^^^^^^^^^^^
// The package MoveItVisualTools provides many capabilties for visualizing objects, robots,
// and trajectories in RViz as well as debugging tools such as step-by-step introspection of a script
namespace rvt = rviz_visual_tools;
moveit_visual_tools::MoveItVisualTools visual_tools("panda_link0");
visual_tools.loadRobotStatePub("/display_robot_state");
visual_tools.enableBatchPublishing();
visual_tools.deleteAllMarkers(); // clear all old markers
visual_tools.trigger();
/* Remote control is an introspection tool that allows users to step through a high level script
via buttons and keyboard shortcuts in RViz */
visual_tools.loadRemoteControl();
/* RViz provides many types of markers, in this demo we will use text, cylinders, and spheres*/
Eigen::Isometry3d text_pose = Eigen::Isometry3d::Identity();
text_pose.translation().z() = 1.75;
visual_tools.publishText(text_pose, "Motion Planning API Demo", rvt::WHITE, rvt::XLARGE);
/* Batch publishing is used to reduce the number of messages being sent to RViz for large visualizations */
visual_tools.trigger();
/* We can also use visual_tools to wait for user input */
visual_tools.prompt("Press 'next' in the RvizVisualToolsGui window to start the demo");
// Pose Goal
// ^^^^^^^^^
// We will now create a motion plan request for the arm of the Panda
// specifying the desired pose of the end-effector as input.
visual_tools.publishRobotState(planning_scene->getCurrentStateNonConst(), rviz_visual_tools::GREEN);
visual_tools.trigger();
planning_interface::MotionPlanRequest req;
planning_interface::MotionPlanResponse res;
geometry_msgs::PoseStamped pose;
pose.header.frame_id = "panda_link0";
pose.pose.position.x = 0.3;
pose.pose.position.y = 0.4;
pose.pose.position.z = 0.75;
pose.pose.orientation.w = 1.0;
// A tolerance of 0.01 m is specified in position
// and 0.01 radians in orientation
std::vector<double> tolerance_pose(3, 0.01);
std::vector<double> tolerance_angle(3, 0.01);
// We will create the request as a constraint using a helper function available
// from the
// `kinematic_constraints`_
// package.
//
// .. _kinematic_constraints:
// http://docs.ros.org/melodic/api/moveit_core/html/namespacekinematic__constraints.html#a88becba14be9ced36fefc7980271e132
moveit_msgs::Constraints pose_goal =
kinematic_constraints::constructGoalConstraints("panda_link8", pose, tolerance_pose, tolerance_angle);
req.group_name = PLANNING_GROUP;
req.goal_constraints.push_back(pose_goal);
// We now construct a planning context that encapsulate the scene,
// the request and the response. We call the planner using this
// planning context
planning_interface::PlanningContextPtr context =
planner_instance->getPlanningContext(planning_scene, req, res.error_code_);
context->solve(res);
if (res.error_code_.val != res.error_code_.SUCCESS)
{
ROS_ERROR("Could not compute plan successfully");
return 0;
}
// Visualize the result
// ^^^^^^^^^^^^^^^^^^^^
ros::Publisher display_publisher =
node_handle.advertise<moveit_msgs::DisplayTrajectory>("/move_group/display_planned_path", 1, true);
moveit_msgs::DisplayTrajectory display_trajectory;
/* Visualize the trajectory */
moveit_msgs::MotionPlanResponse response;
res.getMessage(response);
display_trajectory.trajectory_start = response.trajectory_start;
display_trajectory.trajectory.push_back(response.trajectory);
visual_tools.publishTrajectoryLine(display_trajectory.trajectory.back(), joint_model_group);
visual_tools.trigger();
display_publisher.publish(display_trajectory);
/* Set the state in the planning scene to the final state of the last plan */
robot_state->setJointGroupPositions(joint_model_group, response.trajectory.joint_trajectory.points.back().positions);
planning_scene->setCurrentState(*robot_state.get());
// Display the goal state
visual_tools.publishRobotState(planning_scene->getCurrentStateNonConst(), rviz_visual_tools::GREEN);
visual_tools.publishAxisLabeled(pose.pose, "goal_1");
visual_tools.publishText(text_pose, "Pose Goal (1)", rvt::WHITE, rvt::XLARGE);
visual_tools.trigger();
/* We can also use visual_tools to wait for user input */
visual_tools.prompt("Press 'next' in the RvizVisualToolsGui window to continue the demo");
// Joint Space Goals
// ^^^^^^^^^^^^^^^^^
// Now, setup a joint space goal
robot_state::RobotState goal_state(robot_model);
std::vector<double> joint_values = { -1.0, 0.7, 0.7, -1.5, -0.7, 2.0, 0.0 };
goal_state.setJointGroupPositions(joint_model_group, joint_values);
moveit_msgs::Constraints joint_goal = kinematic_constraints::constructGoalConstraints(goal_state, joint_model_group);
req.goal_constraints.clear();
req.goal_constraints.push_back(joint_goal);
// Call the planner and visualize the trajectory
/* Re-construct the planning context */
context = planner_instance->getPlanningContext(planning_scene, req, res.error_code_);
/* Call the Planner */
context->solve(res);
/* Check that the planning was successful */
if (res.error_code_.val != res.error_code_.SUCCESS)
{
ROS_ERROR("Could not compute plan successfully");
return 0;
}
/* Visualize the trajectory */
res.getMessage(response);
display_trajectory.trajectory.push_back(response.trajectory);
/* Now you should see two planned trajectories in series*/
visual_tools.publishTrajectoryLine(display_trajectory.trajectory.back(), joint_model_group);
visual_tools.trigger();
display_publisher.publish(display_trajectory);
/* We will add more goals. But first, set the state in the planning
scene to the final state of the last plan */
robot_state->setJointGroupPositions(joint_model_group, response.trajectory.joint_trajectory.points.back().positions);
planning_scene->setCurrentState(*robot_state.get());
// Display the goal state
visual_tools.publishRobotState(planning_scene->getCurrentStateNonConst(), rviz_visual_tools::GREEN);
visual_tools.publishAxisLabeled(pose.pose, "goal_2");
visual_tools.publishText(text_pose, "Joint Space Goal (2)", rvt::WHITE, rvt::XLARGE);
visual_tools.trigger();
/* Wait for user input */
visual_tools.prompt("Press 'next' in the RvizVisualToolsGui window to continue the demo");
/* Now, we go back to the first goal to prepare for orientation constrained planning */
req.goal_constraints.clear();
req.goal_constraints.push_back(pose_goal);
context = planner_instance->getPlanningContext(planning_scene, req, res.error_code_);
context->solve(res);
res.getMessage(response);
display_trajectory.trajectory.push_back(response.trajectory);
visual_tools.publishTrajectoryLine(display_trajectory.trajectory.back(), joint_model_group);
visual_tools.trigger();
display_publisher.publish(display_trajectory);
/* Set the state in the planning scene to the final state of the last plan */
robot_state->setJointGroupPositions(joint_model_group, response.trajectory.joint_trajectory.points.back().positions);
planning_scene->setCurrentState(*robot_state.get());
// Display the goal state
visual_tools.publishRobotState(planning_scene->getCurrentStateNonConst(), rviz_visual_tools::GREEN);
visual_tools.trigger();
/* Wait for user input */
visual_tools.prompt("Press 'next' in the RvizVisualToolsGui window to continue the demo");
// Adding Path Constraints
// ^^^^^^^^^^^^^^^^^^^^^^^
// Let's add a new pose goal again. This time we will also add a path constraint to the motion.
/* Let's create a new pose goal */
pose.pose.position.x = 0.32;
pose.pose.position.y = -0.25;
pose.pose.position.z = 0.65;
pose.pose.orientation.w = 1.0;
moveit_msgs::Constraints pose_goal_2 =
kinematic_constraints::constructGoalConstraints("panda_link8", pose, tolerance_pose, tolerance_angle);
/* Now, let's try to move to this new pose goal*/
req.goal_constraints.clear();
req.goal_constraints.push_back(pose_goal_2);
/* But, let's impose a path constraint on the motion.
Here, we are asking for the end-effector to stay level*/
geometry_msgs::QuaternionStamped quaternion;
quaternion.header.frame_id = "panda_link0";
quaternion.quaternion.w = 1.0;
req.path_constraints = kinematic_constraints::constructGoalConstraints("panda_link8", quaternion);
// Imposing path constraints requires the planner to reason in the space of possible positions of the end-effector
// (the workspace of the robot)
// because of this, we need to specify a bound for the allowed planning volume as well;
// Note: a default bound is automatically filled by the WorkspaceBounds request adapter (part of the OMPL pipeline,
// but that is not being used in this example).
// We use a bound that definitely includes the reachable space for the arm. This is fine because sampling is not done
// in this volume
// when planning for the arm; the bounds are only used to determine if the sampled configurations are valid.
req.workspace_parameters.min_corner.x = req.workspace_parameters.min_corner.y =
req.workspace_parameters.min_corner.z = -2.0;
req.workspace_parameters.max_corner.x = req.workspace_parameters.max_corner.y =
req.workspace_parameters.max_corner.z = 2.0;
// Call the planner and visualize all the plans created so far.
context = planner_instance->getPlanningContext(planning_scene, req, res.error_code_);
context->solve(res);
res.getMessage(response);
display_trajectory.trajectory.push_back(response.trajectory);
visual_tools.publishTrajectoryLine(display_trajectory.trajectory.back(), joint_model_group);
visual_tools.trigger();
display_publisher.publish(display_trajectory);
/* Set the state in the planning scene to the final state of the last plan */
robot_state->setJointGroupPositions(joint_model_group, response.trajectory.joint_trajectory.points.back().positions);
planning_scene->setCurrentState(*robot_state.get());
// Display the goal state
visual_tools.publishRobotState(planning_scene->getCurrentStateNonConst(), rviz_visual_tools::GREEN);
visual_tools.publishAxisLabeled(pose.pose, "goal_3");
visual_tools.publishText(text_pose, "Orientation Constrained Motion Plan (3)", rvt::WHITE, rvt::XLARGE);
visual_tools.trigger();
// END_TUTORIAL
/* Wait for user input */
visual_tools.prompt("Press 'next' in the RvizVisualToolsGui window to exit the demo");
planner_instance.reset();
return 0;
}