sim_joy.cpp

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#include <ros/ros.h>
#include <sensor_msgs/Joy.h>
#include <geometry_msgs/TwistStamped.h>

#include <string.h>
#include <vector>

#define COMMAND_TIMEOUT_SEC 0.5

const int PUBLISH_FREQ = 20;

class SimOperator
{
public:
        SimOperator(unsigned int numOfRobots);

        void receiveJoyMessage(const sensor_msgs::Joy::ConstPtr& msg);
        void sendControl();

private:
        unsigned int mNumberOfRobots;
        double mMaxLinearVelocity;
        double mMaxAngularVelocity;

        ros::Subscriber mJoySubscriber;
        std::vector<ros::Publisher> mCommandPublisher;
        std::vector<geometry_msgs::Twist> mCommand;
};

SimOperator::SimOperator(unsigned int numOfRobots)
{
        mNumberOfRobots = numOfRobots;
        mMaxLinearVelocity = 1.0;
        mMaxAngularVelocity = 1.0;

        ros::NodeHandle node;   

        // Subscribe to joystick
        mJoySubscriber = node.subscribe("joy", 10, &SimOperator::receiveJoyMessage, this);

        // Publish commands for every robot in the simulation
        char topic[50];
        for(unsigned int i = 0; i < mNumberOfRobots; i++)
        {
                if(mNumberOfRobots > 1)
                        sprintf(topic, "/robot_%d/cmd_vel", i);
                else
                        sprintf(topic, "/cmd_vel");
                mCommandPublisher.push_back(node.advertise<geometry_msgs::Twist>(topic, 1));

                geometry_msgs::Twist twist;
                mCommand.push_back(twist);
        }
}

void SimOperator::receiveJoyMessage(const sensor_msgs::Joy::ConstPtr& msg)
{
        for(unsigned int i = 0; i < mNumberOfRobots; i++)
        {
                if(msg->buttons[i])
                {
                        mCommand[i].linear.x = msg->axes[1] * mMaxLinearVelocity;
                        mCommand[i].angular.z = msg->axes[0] * mMaxAngularVelocity;
                }else
                {
                        mCommand[i].linear.x = 0;
                        mCommand[i].angular.z = 0;
                }
        }
}

void SimOperator::sendControl()
{
        for(unsigned int i = 0; i < mNumberOfRobots; i++)
        {
                mCommandPublisher[i].publish(mCommand[i]);
        }
}

int main(int argc, char** argv)
{
        // init the ROS node
        ros::init(argc,argv,"SimController");
        ros::NodeHandle node;

        unsigned int num = 1;
        if(argc > 1)
        {
                num = (unsigned int)atoi(argv[1]);
                if(num > 6) num = 6;
        }
        
        ROS_INFO("Using Joystick to operate %d robots in simulation!", num);
        SimOperator simOp(num);

        ros::Rate pub_rate(PUBLISH_FREQ);
        while (node.ok())
        {
                ros::spinOnce();
                simOp.sendControl();
                pub_rate.sleep();
        }

        return 0;
}