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Improve comments for pick-and-place task (moveit#238)
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@FabianSchuetze
FabianSchuetze authored Jul 6, 2024
1 parent fbc05e4 commit 702710d
Showing 1 changed file with 23 additions and 19 deletions.
42 changes: 23 additions & 19 deletions demo/src/pick_place_task.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -144,6 +144,7 @@ void PickPlaceTask::loadParameters() {
rosparam_shortcuts::shutdownIfError(LOGNAME, errors);
}

// Initialize the task pipeline, defining individual movement stages
bool PickPlaceTask::init() {
ROS_INFO_NAMED(LOGNAME, "Initializing task pipeline");
const std::string object = object_name_;
Expand All @@ -153,10 +154,13 @@ bool PickPlaceTask::init() {
task_.reset();
task_.reset(new moveit::task_constructor::Task());

// Individual movement stages are collected within the Task object
Task& t = *task_;
t.stages()->setName(task_name_);
t.loadRobotModel();

/* Create planners used in various stages. Various options are available,
namely Cartesian, MoveIt pipeline, and joint interpolation. */
// Sampling planner
auto sampling_planner = std::make_shared<solvers::PipelinePlanner>();
sampling_planner->setProperty("goal_joint_tolerance", 1e-5);
Expand Down Expand Up @@ -201,7 +205,7 @@ bool PickPlaceTask::init() {
* *
***************************************************/
Stage* initial_state_ptr = nullptr;
{ // Open Hand
{
auto stage = std::make_unique<stages::MoveTo>("open hand", sampling_planner);
stage->setGroup(hand_group_name_);
stage->setGoal(hand_open_pose_);
Expand All @@ -214,7 +218,8 @@ bool PickPlaceTask::init() {
* Move to Pick *
* *
***************************************************/
{ // Move-to pre-grasp
// Connect initial open-hand state with pre-grasp pose defined in the following
{
auto stage = std::make_unique<stages::Connect>(
"move to pick", stages::Connect::GroupPlannerVector{ { arm_group_name_, sampling_planner } });
stage->setTimeout(5.0);
Expand All @@ -229,6 +234,7 @@ bool PickPlaceTask::init() {
***************************************************/
Stage* pick_stage_ptr = nullptr;
{
// A SerialContainer combines several sub-stages, here for picking the object
auto grasp = std::make_unique<SerialContainer>("pick object");
t.properties().exposeTo(grasp->properties(), { "eef", "hand", "group", "ik_frame" });
grasp->properties().configureInitFrom(Stage::PARENT, { "eef", "hand", "group", "ik_frame" });
Expand All @@ -237,10 +243,11 @@ bool PickPlaceTask::init() {
---- * Approach Object *
***************************************************/
{
// Move the eef link forward along its z-axis by an amount within the given min-max range
auto stage = std::make_unique<stages::MoveRelative>("approach object", cartesian_planner);
stage->properties().set("marker_ns", "approach_object");
stage->properties().set("link", hand_frame_);
stage->properties().configureInitFrom(Stage::PARENT, { "group" });
stage->properties().set("link", hand_frame_); // link to perform IK for
stage->properties().configureInitFrom(Stage::PARENT, { "group" }); // inherit group from parent stage
stage->setMinMaxDistance(approach_object_min_dist_, approach_object_max_dist_);

// Set hand forward direction
Expand All @@ -255,29 +262,31 @@ bool PickPlaceTask::init() {
---- * Generate Grasp Pose *
***************************************************/
{
// Sample grasp pose
// Sample grasp pose candidates in angle increments around the z-axis of the object
auto stage = std::make_unique<stages::GenerateGraspPose>("generate grasp pose");
stage->properties().configureInitFrom(Stage::PARENT);
stage->properties().set("marker_ns", "grasp_pose");
stage->setPreGraspPose(hand_open_pose_);
stage->setObject(object);
stage->setObject(object); // object to sample grasps for
stage->setAngleDelta(M_PI / 12);
stage->setMonitoredStage(initial_state_ptr); // hook into successful initial-phase solutions

// Compute IK
// Compute IK for sampled grasp poses
auto wrapper = std::make_unique<stages::ComputeIK>("grasp pose IK", std::move(stage));
wrapper->setMaxIKSolutions(8);
wrapper->setMaxIKSolutions(8); // limit number of solutions
wrapper->setMinSolutionDistance(1.0);
wrapper->setIKFrame(grasp_frame_transform_, hand_frame_);
wrapper->properties().configureInitFrom(Stage::PARENT, { "eef", "group" });
wrapper->properties().configureInitFrom(Stage::INTERFACE, { "target_pose" });
wrapper->setIKFrame(grasp_frame_transform_, hand_frame_); // define virtual frame to reach the target_pose
wrapper->properties().configureInitFrom(Stage::PARENT, { "eef", "group" }); // inherit properties from parent
wrapper->properties().configureInitFrom(Stage::INTERFACE,
{ "target_pose" }); // inherit property from child solution
grasp->insert(std::move(wrapper));
}

/****************************************************
---- * Allow Collision (hand object) *
***************************************************/
{
// Modify planning scene (w/o altering the robot's pose) to allow touching the object for picking
auto stage = std::make_unique<stages::ModifyPlanningScene>("allow collision (hand,object)");
stage->allowCollisions(
object, t.getRobotModel()->getJointModelGroup(hand_group_name_)->getLinkModelNamesWithCollisionGeometry(),
Expand All @@ -300,7 +309,7 @@ bool PickPlaceTask::init() {
***************************************************/
{
auto stage = std::make_unique<stages::ModifyPlanningScene>("attach object");
stage->attachObject(object, hand_frame_);
stage->attachObject(object, hand_frame_); // attach object to hand_frame_
grasp->insert(std::move(stage));
}

Expand Down Expand Up @@ -352,6 +361,7 @@ bool PickPlaceTask::init() {
* *
*****************************************************/
{
// Connect the grasped state to the pre-place state, i.e. realize the object transport
auto stage = std::make_unique<stages::Connect>(
"move to place", stages::Connect::GroupPlannerVector{ { arm_group_name_, sampling_planner } });
stage->setTimeout(5.0);
Expand All @@ -364,6 +374,7 @@ bool PickPlaceTask::init() {
* Place Object *
* *
*****************************************************/
// All placing sub-stages are collected within a serial container again
{
auto place = std::make_unique<SerialContainer>("place object");
t.properties().exposeTo(place->properties(), { "eef", "hand", "group" });
Expand Down Expand Up @@ -498,13 +509,6 @@ bool PickPlaceTask::execute() {
moveit_msgs::MoveItErrorCodes execute_result;

execute_result = task_->execute(*task_->solutions().front());
// // If you want to inspect the goal message, use this instead:
// actionlib::SimpleActionClient<moveit_task_constructor_msgs::ExecuteTaskSolutionAction>
// execute("execute_task_solution", true); execute.waitForServer();
// moveit_task_constructor_msgs::ExecuteTaskSolutionGoal execute_goal;
// task_->solutions().front()->toMsg(execute_goal.solution);
// execute.sendGoalAndWait(execute_goal);
// execute_result = execute.getResult()->error_code;

if (execute_result.val != moveit_msgs::MoveItErrorCodes::SUCCESS) {
ROS_ERROR_STREAM_NAMED(LOGNAME, "Task execution failed and returned: " << execute_result.val);
Expand Down

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