Skill place
Version: 1.0.0
Default path:
/skill/placeDatatype: manipulation_skills/action/Place
Definition source:
package.xmlin ros4hri/manipulation_skills
Commands the robot to place an object at a specified location. This skill sends a goal to the robot’s manipulation system to execute a placing action.
- Once invoked, the robot will:
Move to the target location.
Release the object.
Return to a safe position.
Typical uses include placing objects on tables, shelves, or designated drop-off points.
The skill assumes that the robot is already holding an object. See Skill grasp for the grasping action.
Input parameters
target
geometry_msgs/msg/PoseStamped, requiredThe target pose where the object should be placed. This includes position and orientation.
release_upon_completion
boolean, default:TrueIf
true, the robot will release the object upon reaching the target pose. Iffalse, the robot will move to the target pose without releasing the object.side
string, default:""Which hand or end-effector to use. Supported values:
left: Use the left hand.right: Use the right hand.default (empty string): Use the default hand.
constraint manipulation_skills/msg/Constraint
The motion planning constraint to apply. Contains:
constraint_type(uint8): type of constraint0:FREE_PLAN(no constraint)1:ORIENTATION_CONSTRAINT(apply orientation constraint)
orientation_constraint(moveit_msgs/OrientationConstraint): the actual orientation constraint to use ifconstraint_type = ORIENTATION_CONSTRAINT.
Quick snippets
Call the skill from the command-line
$ ros2 action send_goal /skill/place manipulation_skills/action/Place # then press Tab to complete the message prototype
Call the action from a Python script:
#!/usr/bin/env python
import rclpy
from rclpy.action import ActionClient
from rclpy.node import Node
from manipulation_skills.action import
class PlaceActionClient(Node):
def __init__(self):
super().__init__('place_client')
self._action_client = ActionClient(self, , '/skill/place')
def send_goal(self, a, b):
goal_msg = .Goal()
# TODO: adapt to the action's parameters
# check the PlaceGoal message
# definition for the possible goal parameters
# goal_msg.a = a
# goal_msg.b = b
self._action_client.wait_for_server()
return self._action_client.send_goal_async(goal_msg)
if __name__ == '__main__':
rclpy.init(args=args)
action_client = ActionClient()
# TODO: adapt to your action's parameters
future = action_client.send_goal(a, b)
rclpy.spin_until_future_complete(action_client, future)
rclpy.shutdown()
Call the action from a C++ program:
#include <functional>
#include <future>
#include <memory>
#include <string>
#include <sstream>
#include <chrono>
#include "manipulation_skills/action/.hpp"
#include "rclcpp/rclcpp.hpp"
#include "rclcpp_action/rclcpp_hpp"
#include "rclcpp_components/register_node_macro.hpp"
using namespace std::chrono_literals;
using namespace std;
class PlaceActionClient : public rclcpp::Node
{
public:
using = manipulation_skills::action::;
using GoalHandle = rclcpp_action::ClientGoalHandle<>;
explicit PlaceActionClient(const rclcpp::NodeOptions & options)
: Node("place_action_client", options)
{
this->client_ptr_ = rclcpp_action::create_client<>(
this,
"");
this->timer_ = this->create_wall_timer(
500ms,
bind(&PlaceActionClient::send_goal, this));
}
void send_goal()
{
using namespace std::placeholders;
this->timer_->cancel();
if (!this->client_ptr_->wait_for_action_server()) {
RCLCPP_ERROR(this->get_logger(), "Action server not available after waiting");
rclcpp::shutdown();
}
auto goal_msg = ::Goal();
// check the PlaceGoal message
// definition for the possible goal parameters
// goal_msg.... = ...;
RCLCPP_INFO(this->get_logger(), "Sending goal");
auto send_goal_options = rclcpp_action::Client<>::SendGoalOptions();
send_goal_options.goal_response_callback =
bind(&PlaceActionClient::goal_response_callback, this, _1);
send_goal_options.feedback_callback =
bind(&PlaceActionClient::feedback_callback, this, _1, _2);
send_goal_options.result_callback =
bind(&PlaceActionClient::result_callback, this, _1);
this->client_ptr_->async_send_goal(goal_msg, send_goal_options);
}
private:
rclcpp_action::Client<>::SharedPtr client_ptr_;
rclcpp::TimerBase::SharedPtr timer_;
void goal_response_callback(const GoalHandle::SharedPtr & goal_handle)
{
if (!goal_handle) {
RCLCPP_ERROR(this->get_logger(), "Goal was rejected by server");
} else {
RCLCPP_INFO(this->get_logger(), "Goal accepted by server, waiting for result");
}
}
void feedback_callback(
GoalHandle::SharedPtr,
const shared_ptr<const ::Feedback> feedback)
{
stringstream ss;
ss << "Next number in sequence received: ";
for (auto number : feedback->partial_sequence) {
ss << number << " ";
}
RCLCPP_INFO(this->get_logger(), ss.str().c_str());
}
void result_callback(const GoalHandle::WrappedResult & result)
{
switch (result.code) {
case rclcpp_action::ResultCode::SUCCEEDED:
break;
case rclcpp_action::ResultCode::ABORTED:
RCLCPP_ERROR(this->get_logger(), "Goal was aborted");
return;
case rclcpp_action::ResultCode::CANCELED:
RCLCPP_ERROR(this->get_logger(), "Goal was canceled");
return;
default:
RCLCPP_ERROR(this->get_logger(), "Unknown result code");
return;
}
stringstream ss;
ss << "Result received: ";
for (auto number : result.result->sequence) {
ss << number << " ";
}
RCLCPP_INFO(this->get_logger(), ss.str().c_str());
rclcpp::shutdown();
}
}; // class PlaceActionClient
RCLCPP_COMPONENTS_REGISTER_NODE(PlaceActionClient)
You can call this skill from QML using the following code snippet. See ros_qml_plugin to learn more.
import Ros 2.0
// ...
PlaceSkill {
id: mySkill
onResult: {
console.log("Skill result: " + result);
}
onFeedback: {
console.log("Skill feedback: " + feedback);
}
}
// Call the skill
mySkill.place();
See also
List of other Manipulation skills
List of other Motions skills