driver.cc

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// Copyright (C) 2007, 2009-2012 Austin Robot Technology, Patrick Beeson, Jack O'Quin
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#include <string>
#include <cmath>

#include <ros/ros.h>
#include <tf/transform_listener.h>
#include <velodyne_msgs/VelodyneScan.h>

#include "velodyne_driver/driver.h"

namespace velodyne_driver
{

VelodyneDriver::VelodyneDriver(ros::NodeHandle node,
                               ros::NodeHandle private_nh)
{
  // use private node handle to get parameters
  private_nh.param("frame_id", config_.frame_id, std::string("velodyne"));
  std::string tf_prefix = tf::getPrefixParam(private_nh);
  ROS_DEBUG_STREAM("tf_prefix: " << tf_prefix);
  config_.frame_id = tf::resolve(tf_prefix, config_.frame_id);

  // get model name, validate string, determine packet rate
  private_nh.param("model", config_.model, std::string("64E"));
  double packet_rate;                   // packet frequency (Hz)
  std::string model_full_name;
  if ((config_.model == "64E_S2") || 
      (config_.model == "64E_S2.1"))    // generates 1333312 points per second
    {                                   // 1 packet holds 384 points
      packet_rate = 3472.17;            // 1333312 / 384
      model_full_name = std::string("HDL-") + config_.model;
    }
  else if (config_.model == "64E")
    {
      packet_rate = 2600.0;
      model_full_name = std::string("HDL-") + config_.model;
    }
  else if (config_.model == "64E_S3") // generates 2222220 points per second (half for strongest and half for lastest)
    {                                 // 1 packet holds 384 points
      packet_rate = 5787.03;          // 2222220 / 384
      model_full_name = std::string("HDL-") + config_.model;
    }
  else if (config_.model == "32E")
    {
      packet_rate = 1808.0;
      model_full_name = std::string("HDL-") + config_.model;
    }
    else if (config_.model == "32C")
    {
      packet_rate = 1507.0;
      model_full_name = std::string("VLP-") + config_.model;
    }
  else if (config_.model == "VLP16")
    {
      packet_rate = 754;             // 754 Packets/Second for Last or Strongest mode 1508 for dual (VLP-16 User Manual)
      model_full_name = "VLP-16";
    }
  else
    {
      ROS_ERROR_STREAM("unknown Velodyne LIDAR model: " << config_.model);
      packet_rate = 2600.0;
    }
  std::string deviceName(std::string("Velodyne ") + model_full_name);

  private_nh.param("rpm", config_.rpm, 600.0);
  ROS_INFO_STREAM(deviceName << " rotating at " << config_.rpm << " RPM");
  double frequency = (config_.rpm / 60.0);     // expected Hz rate

  // default number of packets for each scan is a single revolution
  // (fractions rounded up)
  config_.npackets = (int) ceil(packet_rate / frequency);
  private_nh.getParam("npackets", config_.npackets);
  ROS_INFO_STREAM("publishing " << config_.npackets << " packets per scan");

  std::string dump_file;
  private_nh.param("pcap", dump_file, std::string(""));

  double cut_angle;
  private_nh.param("cut_angle", cut_angle, -0.01);
  if (cut_angle < 0.0)
  {
    ROS_INFO_STREAM("Cut at specific angle feature deactivated.");
  }
  else if (cut_angle < (2*M_PI))
  {
      ROS_INFO_STREAM("Cut at specific angle feature activated. " 
        "Cutting velodyne points always at " << cut_angle << " rad.");
  }
  else
  {
    ROS_ERROR_STREAM("cut_angle parameter is out of range. Allowed range is "
    << "between 0.0 and 2*PI or negative values to deactivate this feature.");
    cut_angle = -0.01;
  }

  // Convert cut_angle from radian to one-hundredth degree, 
  // which is used in velodyne packets
  config_.cut_angle = int((cut_angle*360/(2*M_PI))*100);

  int udp_port;
  private_nh.param("port", udp_port, (int) DATA_PORT_NUMBER);

  // Initialize dynamic reconfigure
  srv_ = boost::make_shared <dynamic_reconfigure::Server<velodyne_driver::
    VelodyneNodeConfig> > (private_nh);
  dynamic_reconfigure::Server<velodyne_driver::VelodyneNodeConfig>::
    CallbackType f;
  f = boost::bind (&VelodyneDriver::callback, this, _1, _2);
  srv_->setCallback (f); // Set callback function und call initially

  // initialize diagnostics
  diagnostics_.setHardwareID(deviceName);
  const double diag_freq = packet_rate/config_.npackets;
  diag_max_freq_ = diag_freq;
  diag_min_freq_ = diag_freq;
  ROS_INFO("expected frequency: %.3f (Hz)", diag_freq);

  using namespace diagnostic_updater;
  diag_topic_.reset(new TopicDiagnostic("velodyne_packets", diagnostics_,
                                        FrequencyStatusParam(&diag_min_freq_,
                                                             &diag_max_freq_,
                                                             0.1, 10),
                                        TimeStampStatusParam()));
  diag_timer_ = private_nh.createTimer(ros::Duration(0.2), &VelodyneDriver::diagTimerCallback,this);

  config_.enabled = true;

  // open Velodyne input device or file
  if (dump_file != "")                  // have PCAP file?
    {
      // read data from packet capture file
      input_.reset(new velodyne_driver::InputPCAP(private_nh, udp_port,
                                                  packet_rate, dump_file));
    }
  else
    {
      // read data from live socket
      input_.reset(new velodyne_driver::InputSocket(private_nh, udp_port));
    }

  // raw packet output topic
  output_ =
    node.advertise<velodyne_msgs::VelodyneScan>("velodyne_packets", 10);

  last_azimuth_ = -1;
}

bool VelodyneDriver::poll(void)
{
  if (!config_.enabled) {
    // If we are not enabled exit once a second to let the caller handle
    // anything it might need to, such as if it needs to exit.
    ros::Duration(1).sleep();
    return true;
  }

  // Allocate a new shared pointer for zero-copy sharing with other nodelets.
  velodyne_msgs::VelodyneScanPtr scan(new velodyne_msgs::VelodyneScan);

  if( config_.cut_angle >= 0) //Cut at specific angle feature enabled
  {
    scan->packets.reserve(config_.npackets);
    velodyne_msgs::VelodynePacket tmp_packet;
    while(true)
    {
      while(true)
      {
        int rc = input_->getPacket(&tmp_packet, config_.time_offset);
        if (rc == 0) break;       // got a full packet?
        if (rc < 0) return false; // end of file reached?
      }
      scan->packets.push_back(tmp_packet);

      // Extract base rotation of first block in packet
      std::size_t azimuth_data_pos = 100*0+2;
      int azimuth = *( (u_int16_t*) (&tmp_packet.data[azimuth_data_pos]));

      //if first packet in scan, there is no "valid" last_azimuth_
      if (last_azimuth_ == -1) {
         last_azimuth_ = azimuth;
         continue;
      }
      if((last_azimuth_ < config_.cut_angle && config_.cut_angle <= azimuth)
         || ( config_.cut_angle <= azimuth && azimuth < last_azimuth_)
         || (azimuth < last_azimuth_ && last_azimuth_ < config_.cut_angle))
      {
        last_azimuth_ = azimuth;
        break; // Cut angle passed, one full revolution collected
      }
      last_azimuth_ = azimuth;
    }
  }
  else // standard behaviour
  {
  // Since the velodyne delivers data at a very high rate, keep
  // reading and publishing scans as fast as possible.
    scan->packets.resize(config_.npackets);
    for (int i = 0; i < config_.npackets; ++i)
    {
      while (true)
        {
          // keep reading until full packet received
          int rc = input_->getPacket(&scan->packets[i], config_.time_offset);
          if (rc == 0) break;       // got a full packet?
          if (rc < 0) return false; // end of file reached?
        }
    }
  }

  // publish message using time of last packet read
  ROS_DEBUG("Publishing a full Velodyne scan.");
  scan->header.stamp = scan->packets.back().stamp;
  scan->header.frame_id = config_.frame_id;
  output_.publish(scan);

  // notify diagnostics that a message has been published, updating
  // its status
  diag_topic_->tick(scan->header.stamp);
  diagnostics_.update();

  return true;
}

void VelodyneDriver::callback(velodyne_driver::VelodyneNodeConfig &config,
              uint32_t level)
{
  ROS_INFO("Reconfigure Request");
  if (level & 1)
  {
    config_.time_offset = config.time_offset;
  }
  if (level & 2)
  {
    config_.enabled = config.enabled;
  }
}

void VelodyneDriver::diagTimerCallback(const ros::TimerEvent &event)
{
  (void)event;
  // Call necessary to provide an error when no velodyne packets are received
  diagnostics_.update();
}

} // namespace velodyne_driver