node.cpp

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/*
 * Copyright (c) 2014, RoboPeak
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, 
 *    this list of conditions and the following disclaimer in the documentation 
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
/*
 *  RoboPeak LIDAR System
 *  RPlidar ROS Node
 *
 *  Copyright 2009 - 2014 RoboPeak Team
 *  http://www.robopeak.com
 * 
 */



#include "ros/ros.h"
#include "sensor_msgs/LaserScan.h"
#include "std_srvs/Empty.h"

#include "rplidar.h" //RPLIDAR standard sdk, all-in-one header

#ifndef _countof
#define _countof(_Array) (int)(sizeof(_Array) / sizeof(_Array[0]))
#endif

#define DEG2RAD(x) ((x)*M_PI/180.)

using namespace rp::standalone::rplidar;

RPlidarDriver * drv = NULL;

void publish_scan(ros::Publisher *pub, 
                  rplidar_response_measurement_node_t *nodes, 
                  size_t node_count, ros::Time start,
                  double scan_time, bool inverted, 
                  float angle_min, float angle_max, 
                  std::string frame_id)
{
    static int scan_count = 0;
    sensor_msgs::LaserScan scan_msg;

    scan_msg.header.stamp = start;
    scan_msg.header.frame_id = frame_id;
    scan_count++;

    scan_msg.angle_min =  M_PI - angle_min;
    scan_msg.angle_max =  M_PI - angle_max;
    scan_msg.angle_increment = 
        (scan_msg.angle_max - scan_msg.angle_min) / (double)(node_count-1);

    scan_msg.scan_time = scan_time;
    scan_msg.time_increment = scan_time / (double)(node_count-1);

    scan_msg.range_min = 0.15;
    scan_msg.range_max = 6.;

    scan_msg.intensities.resize(node_count);
    scan_msg.ranges.resize(node_count);
    if (!inverted) { // assumes scan window at the top
        for (size_t i = 0; i < node_count; i++) {
            float read_value = (float) nodes[i].distance_q2/4.0f/1000;
            if (read_value == 0.0)
                scan_msg.ranges[i] = std::numeric_limits<float>::infinity();
            else
                scan_msg.ranges[i] = read_value;
            scan_msg.intensities[i] = (float) (nodes[i].sync_quality >> 2);
        }
    } else {
        for (size_t i = 0; i < node_count; i++) {
            float read_value = (float)nodes[i].distance_q2/4.0f/1000;
            if (read_value == 0.0)
                scan_msg.ranges[node_count-1-i] = std::numeric_limits<float>::infinity();
            else
                scan_msg.ranges[node_count-1-i] = read_value;
            scan_msg.intensities[node_count-1-i] = (float) (nodes[i].sync_quality >> 2);
        }
    }

    pub->publish(scan_msg);
}

bool checkRPLIDARHealth(RPlidarDriver * drv)
{
    u_result     op_result;
    rplidar_response_device_health_t healthinfo;

    op_result = drv->getHealth(healthinfo);
    if (IS_OK(op_result)) { 
        printf("RPLidar health status : %d\n", healthinfo.status);
        
        if (healthinfo.status == RPLIDAR_STATUS_ERROR) {
            fprintf(stderr, "Error, rplidar internal error detected."
                            "Please reboot the device to retry.\n");
            return false;
        } else {
            return true;
        }

    } else {
        fprintf(stderr, "Error, cannot retrieve rplidar health code: %x\n", 
                        op_result);
        return false;
    }
}

bool stop_motor(std_srvs::Empty::Request &req,
                                std_srvs::Empty::Response &res)
{
  if(!drv)
        return false;

  ROS_DEBUG("Stop motor");
  drv->stop();
  drv->stopMotor();
  return true;
}

bool start_motor(std_srvs::Empty::Request &req,
                                std_srvs::Empty::Response &res)
{
  if(!drv)
        return false;
  ROS_DEBUG("Start motor");
  drv->startMotor();
  drv->startScan();;
  return true;
}


int main(int argc, char * argv[]) {
    ros::init(argc, argv, "rplidar_node");

    std::string serial_port;
    int serial_baudrate = 115200;
    std::string frame_id;
    bool inverted = false;
    bool angle_compensate = true;

    ros::NodeHandle nh;
    ros::Publisher scan_pub = nh.advertise<sensor_msgs::LaserScan>("scan", 1000);
    ros::NodeHandle nh_private("~");
    nh_private.param<std::string>("serial_port", serial_port, "/dev/ttyUSB0"); 
    nh_private.param<int>("serial_baudrate", serial_baudrate, 115200); 
    nh_private.param<std::string>("frame_id", frame_id, "laser_frame");
    nh_private.param<bool>("inverted", inverted, "false");
    nh_private.param<bool>("angle_compensate", angle_compensate, "true");
        
    u_result     op_result;
   
    // create the driver instance
        drv = RPlidarDriver::CreateDriver(RPlidarDriver::DRIVER_TYPE_SERIALPORT);
    
    if (!drv) {
        fprintf(stderr, "Create Driver fail, exit\n");
        return -2;
    }

    // make connection...
    if (IS_FAIL(drv->connect(serial_port.c_str(), (_u32)serial_baudrate))) {
        fprintf(stderr, "Error, cannot bind to the specified serial port %s.\n"
            , serial_port.c_str());
        RPlidarDriver::DisposeDriver(drv);
        return -1;
    }

    // check health...
    if (!checkRPLIDARHealth(drv)) {
        RPlidarDriver::DisposeDriver(drv);
        return -1;
    }


        ros::ServiceServer stop_motor_service = nh.advertiseService("stop_motor", stop_motor);
        ros::ServiceServer start_motor_service = nh.advertiseService("start_motor", start_motor);
        
    // start scan...
    drv->startScan();

    ros::Time start_scan_time;
    ros::Time end_scan_time;
    double scan_duration;
    while (ros::ok()) {

        rplidar_response_measurement_node_t nodes[360*2];
        size_t   count = _countof(nodes);

        start_scan_time = ros::Time::now();
        op_result = drv->grabScanData(nodes, count);
        end_scan_time = ros::Time::now();
        scan_duration = (end_scan_time - start_scan_time).toSec() * 1e-3;

        if (op_result == RESULT_OK) {
            op_result = drv->ascendScanData(nodes, count);

            float angle_min = DEG2RAD(0.0f);
            float angle_max = DEG2RAD(359.0f);
            if (op_result == RESULT_OK) {
                if (angle_compensate) {
                    const int angle_compensate_nodes_count = 360;
                    const int angle_compensate_multiple = 1;
                    int angle_compensate_offset = 0;
                    rplidar_response_measurement_node_t angle_compensate_nodes[angle_compensate_nodes_count];
                    memset(angle_compensate_nodes, 0, angle_compensate_nodes_count*sizeof(rplidar_response_measurement_node_t));
                    int i = 0, j = 0;
                    for( ; i < count; i++ ) {
                        if (nodes[i].distance_q2 != 0) {
                            float angle = (float)((nodes[i].angle_q6_checkbit >> RPLIDAR_RESP_MEASUREMENT_ANGLE_SHIFT)/64.0f);
                            int angle_value = (int)(angle * angle_compensate_multiple);
                            if ((angle_value - angle_compensate_offset) < 0) angle_compensate_offset = angle_value;
                            for (j = 0; j < angle_compensate_multiple; j++) {
                                angle_compensate_nodes[angle_value-angle_compensate_offset+j] = nodes[i];
                            }
                        }
                    }
  
                    publish_scan(&scan_pub, angle_compensate_nodes, angle_compensate_nodes_count,
                             start_scan_time, scan_duration, inverted,  
                             angle_min, angle_max, 
                             frame_id);
                } else {
                    int start_node = 0, end_node = 0;
                    int i = 0;
                    // find the first valid node and last valid node
                    while (nodes[i++].distance_q2 == 0);
                    start_node = i-1;
                    i = count -1;
                    while (nodes[i--].distance_q2 == 0);
                    end_node = i+1;

                    angle_min = DEG2RAD((float)(nodes[start_node].angle_q6_checkbit >> RPLIDAR_RESP_MEASUREMENT_ANGLE_SHIFT)/64.0f);
                    angle_max = DEG2RAD((float)(nodes[end_node].angle_q6_checkbit >> RPLIDAR_RESP_MEASUREMENT_ANGLE_SHIFT)/64.0f);

                    publish_scan(&scan_pub, &nodes[start_node], end_node-start_node +1, 
                             start_scan_time, scan_duration, inverted,  
                             angle_min, angle_max, 
                             frame_id);
               }
            } else if (op_result == RESULT_OPERATION_FAIL) {
                // All the data is invalid, just publish them
                float angle_min = DEG2RAD(0.0f);
                float angle_max = DEG2RAD(359.0f);

                publish_scan(&scan_pub, nodes, count, 
                             start_scan_time, scan_duration, inverted,  
                             angle_min, angle_max, 
                             frame_id);
            }
        }

        ros::spinOnce();
    }
        
    // done!
        RPlidarDriver::DisposeDriver(drv);
    return 0;
}