pxmlw6n2f/Gazebo_Distributed_TCP/plugins/HarnessPlugin.hh

135 lines
4.5 KiB
C++

/*
* Copyright (C) 2016 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.
*
*/
#ifndef GAZEBO_PLUGINS_HARNESSPLUGIN_HH_
#define GAZEBO_PLUGINS_HARNESSPLUGIN_HH_
#include <string>
#include <vector>
#include "gazebo/transport/TransportTypes.hh"
#include "gazebo/common/PID.hh"
#include "gazebo/common/Plugin.hh"
namespace gazebo
{
/// \brief This plugin is designed to lower a model at a controlled rate.
/// Joints between a harness model and a model to lower are created
/// according to SDF provided to this plugin.
///
/// A winch joint and detach joint can be specified. The winch joint,
/// ideally a prismatic joint, has a PID controller. The detach joint,
/// which can be the same joint as the winch joint, is detached on a given
/// signal.
///
/// Two topics are created:
///
/// 1. ~/<plugin_model_name>/harness/velocity
/// - Message Type: GzString, expected to be a float
/// - Purpose: Set target winch velocity
///
/// 2. ~/<plugin_model_name>/harness/detach
/// - Message Type: GzString, expected to be a bool ("true")
/// - Purpose: Detach the <detach> joint.
///
/// For an example refer to:
/// - World file: worlds/harness.world
/// - Code: examples/stand_alone/harness
class GAZEBO_VISIBLE HarnessPlugin : public ModelPlugin
{
/// \brief Constructor.
public: HarnessPlugin();
/// \brief Destructor.
public: virtual ~HarnessPlugin();
// Documentation Inherited.
public: virtual void Load(physics::ModelPtr _model, sdf::ElementPtr _sdf);
// Documentation Inherited.
public: virtual void Init();
/// \brief Set the target winch velocity
/// \param[in] _value Target winch velocity.
public: void SetWinchVelocity(const float _value);
/// \brief Get the current winch velocity
/// \return Velocity of the winch joint
public: double WinchVelocity() const;
/// \brief Detach the <detach> joint. Once the joint is detached, it
/// cannot be reattached.
public: void Detach();
/// \brief Callback for World Update events.
/// \param[in] _info Update information
private: void OnUpdate(const common::UpdateInfo &_info);
/// \brief Velocity control callback.
/// \param[in] _msg Message data, interpreted as a float
private: void OnVelocity(ConstGzStringPtr &_msg);
/// \brief Detach control callback.
/// \param[in] _msg Message data, interpreted as a bool
private: void OnDetach(ConstGzStringPtr &_msg);
/// \brief Get the index of a joint with the given name.
/// \param[in] _name Name of the joint to find.
/// \return Index into this->jointsto
private: int JointIndex(const std::string &_name) const;
/// \brief Vector of joints
private: std::vector<physics::JointPtr> joints;
/// \brief Index into the joints vector that specifies the winch joint.
private: int winchIndex = 0;
/// \brief Index into the joints vector that specifies the joint to detach.
private: int detachIndex = 0;
/// \brief Position PID controller for the winch
private: common::PID winchPosPID;
/// \brief Velocity PID controller for the winch
private: common::PID winchVelPID;
/// \brief Target winch position
private: float winchTargetPos = 0.0;
/// \brief Target winch velocity
private: float winchTargetVel = 0.0;
/// \brief Previous simulation time
private: common::Time prevSimTime = common::Time::Zero;
/// \brief Communication node
/// \todo: Transition to ignition-transport in gazebo8
private: transport::NodePtr node;
/// \brief Velocity control subscriber
/// \todo: Transition to ignition-transport in gazebo8
private: transport::SubscriberPtr velocitySub;
/// \brief Detach control subscriber
/// \todo: Transition to ignition-transport in gazebo8
private: transport::SubscriberPtr detachSub;
/// \brief Connection to World Update events.
private: event::ConnectionPtr updateConnection;
};
}
#endif