Bring back the gazebo plugins (#1063)

The models and meshes are not included. We will need to find an alternate way to reintegrate these and use them. * Add simulation/gz_msgs back, and build with Gradle. * Add back in the frc simulation plugins for gazebo. * Add a new shared library, halsim_gazebo. This library will become the interface between the HAL sim layer and gazebo. * Preserve the first channel number used in created Encoders in the Sim MockData. This allows us to use the DIO channel number to connect with simulated encoders. * Have the HAL Simulator set the reverse direction on creation. This enables a simulator to be aware of the direction. * Add a drive_motor plugin. This is a bit of a 'magic' motor, which allows us to build robot models that drive in a more realistic fashion. It does this by apply forces directly to the chassis, rather than relying on the complex motion dynamics of a driven wheel. This in turn allows the model to reduce wheel friction, reducing scrub, and allowing for a more natural driving experience.
2026-06-25 01:41:43 +00:00 · 2018-06-30 02:45:21 -05:00
parent 70960b0251
commit ebd41fe0bb
60 changed files with 5278 additions and 1 deletions
--- a/simulation/frc_gazebo_plugins/src/drive_motor/cpp/drive_motor.cpp
+++ b/simulation/frc_gazebo_plugins/src/drive_motor/cpp/drive_motor.cpp
@@ -0,0 +1,134 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2016-2018 FIRST. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include "drive_motor.h"
+
+#include <boost/algorithm/string/replace.hpp>
+
+GZ_REGISTER_MODEL_PLUGIN(DriveMotor)
+
+void DriveMotor::Load(gazebo::physics::ModelPtr model, sdf::ElementPtr sdf) {
+  this->model = model;
+  signal = 0;
+
+  // Parse SDF properties
+  joint = model->GetJoint(sdf->Get<std::string>("joint"));
+  if (!joint) {
+    gzerr << "Error initializing drive motor: could not get joint";
+    return;
+  }
+
+  parent = joint->GetParent();
+  if (!parent) {
+    gzerr << "Error initializing drive motor: could not get parent";
+    return;
+  }
+
+  child = joint->GetChild();
+  if (!child) {
+    gzerr << "Error initializing drive motor: could not get child";
+    return;
+  }
+
+  if (sdf->HasElement("topic")) {
+    topic = sdf->Get<std::string>("topic");
+  } else {
+    topic = "~/" + sdf->GetAttribute("name")->GetAsString();
+  }
+
+  if (sdf->HasElement("max_speed")) {
+    maxSpeed = sdf->Get<double>("max_speed");
+  } else {
+    maxSpeed = 0;
+  }
+
+  if (sdf->HasElement("multiplier")) {
+    multiplier = sdf->Get<double>("multiplier");
+  } else {
+    multiplier = 1;
+  }
+
+  if (sdf->HasElement("dx")) {
+    dx = sdf->Get<double>("dx");
+  } else {
+    dx = 0;
+  }
+
+  if (sdf->HasElement("dy")) {
+    dy = sdf->Get<double>("dy");
+  } else {
+    dy = 0;
+  }
+
+  if (sdf->HasElement("dz")) {
+    dz = sdf->Get<double>("dz");
+  } else {
+    dz = 0;
+  }
+
+  gzmsg << "Initializing drive motor: " << topic
+        << " parent=" << parent->GetName() << " directions=" << dx << " " << dy
+        << " " << dz << " multiplier=" << multiplier << std::endl;
+
+  // Connect to Gazebo transport for messaging
+  std::string scoped_name =
+      model->GetWorld()->GetName() + "::" + model->GetScopedName();
+  boost::replace_all(scoped_name, "::", "/");
+  node = gazebo::transport::NodePtr(new gazebo::transport::Node());
+  node->Init(scoped_name);
+  sub = node->Subscribe(topic, &DriveMotor::Callback, this);
+
+  // Connect to the world update event.
+  // This will trigger the Update function every Gazebo iteration
+  updateConn = gazebo::event::Events::ConnectWorldUpdateBegin(
+      boost::bind(&DriveMotor::Update, this, _1));
+}
+
+static double computeForce(double input, double velocity, double max) {
+  double output = input;
+  if (max == 0.0) return output;
+  if (std::fabs(velocity) >= max) {
+    output = 0;
+  } else {
+    double reduce = (max - std::fabs(velocity)) / max;
+    output *= reduce;
+  }
+  return output;
+}
+
+void DriveMotor::Update(const gazebo::common::UpdateInfo& info) {
+#if GAZEBO_MAJOR_VERSION >= 8
+  ignition::math::Vector3d velocity = parent->RelativeLinearVel();
+#else
+  ignition::math::Vector3d velocity = parent->GetRelativeLinearVel().Ign();
+#endif
+
+  if (signal == 0) return;
+
+  double x = computeForce(signal * dx * multiplier, velocity.X(),
+                          std::fabs(maxSpeed * dx));
+  double y = computeForce(signal * dy * multiplier, velocity.Y(),
+                          std::fabs(maxSpeed * dy));
+  double z = computeForce(signal * dz * multiplier, velocity.Z(),
+                          std::fabs(maxSpeed * dz));
+
+  ignition::math::Vector3d force(x, y, z);
+#if GAZEBO_MAJOR_VERSION >= 8
+  parent->AddLinkForce(force, child->RelativePose().Pos());
+#else
+  parent->AddLinkForce(force, child->GetRelativePose().Ign().Pos());
+#endif
+}
+
+void DriveMotor::Callback(const gazebo::msgs::ConstFloat64Ptr& msg) {
+  signal = msg->data();
+  if (signal < -1) {
+    signal = -1;
+  } else if (signal > 1) {
+    signal = 1;
+  }
+}