allwpilib/simulation/frc_gazebo_plugins/pneumatic_piston/src/pneumatic_piston.cpp

/*----------------------------------------------------------------------------*/
/* Copyright (c) FIRST 2016. All Rights Reserved.                             */
/* Open Source Software - may be modified and shared by FRC teams. The code   */
/* must be accompanied by the FIRST BSD license file in the root directory of */
/* the project.                                                               */
/*----------------------------------------------------------------------------*/

#ifdef _WIN32
// Ensure that Winsock2.h is included before Windows.h, which can get
// pulled in by anybody (e.g., Boost).
#include <Winsock2.h>
#endif

#include "pneumatic_piston.h"

#include <boost/algorithm/string/replace.hpp>
#include <gazebo/physics/physics.hh>
#include <gazebo/transport/transport.hh>

GZ_REGISTER_MODEL_PLUGIN(PneumaticPiston)

void PneumaticPiston::Load(physics::ModelPtr model, sdf::ElementPtr sdf) {
  this->model = model;
  signal = 0;

  // Parse SDF properties
  joint = model->GetJoint(sdf->Get<std::string>("joint"));
  if (sdf->HasElement("topic")) {
    topic = sdf->Get<std::string>("topic");
  } else {
    topic = "~/" + sdf->GetAttribute("name")->GetAsString();
  }

  forward_force = sdf->Get<double>("forward-force");
  reverse_force = sdf->Get<double>("reverse-force");

  if (sdf->HasElement("direction") &&
      sdf->Get<std::string>("direction") == "reversed") {
    forward_force = -forward_force;
    reverse_force = -reverse_force;
  }

  gzmsg << "Initializing piston: " << topic << " joint=" << joint->GetName()
        << " forward_force=" << forward_force
        << " reverse_force=" << reverse_force << std::endl;

  // Connect to Gazebo transport for messaging
  std::string scoped_name =
      model->GetWorld()->GetName() + "::" + model->GetScopedName();
  boost::replace_all(scoped_name, "::", "/");
  node = transport::NodePtr(new transport::Node());
  node->Init(scoped_name);
  sub = node->Subscribe(topic, &PneumaticPiston::Callback, this);

  // Connect to the world update event.
  // This will trigger the Update function every Gazebo iteration
  updateConn = event::Events::ConnectWorldUpdateBegin(
      boost::bind(&PneumaticPiston::Update, this, _1));
}

void PneumaticPiston::Update(const common::UpdateInfo& info) {
  joint->SetForce(0, signal);
}

void PneumaticPiston::Callback(const msgs::ConstFloat64Ptr& msg) {
  if (msg->data() < -0.001) {
    signal = -reverse_force;
  } else if (msg->data() > 0.001) {
    signal = forward_force;
  }
}