diffbot_base.cpp

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#include <ros/ros.h>
#include <diffbot_base/diffbot_hw_interface.h>
#include <controller_manager/controller_manager.h>
 
int main(int argc, char **argv)
{
    // Initialize the ROS node
    ros::init(argc, argv, "diffbot_hw_interface");
    ros::NodeHandle nh;
    
    // Create an instance of your robot so that this instance knows about all 
    // the resources that are available.
    diffbot_base::DiffBotHWInterface diffBot(nh);
 
    // Create an instance of the controller manager and pass it the robot, 
    // so that it can handle its resources.
    controller_manager::ControllerManager cm(&diffBot);
    
    // Setup a separate thread that will be used to service ROS callbacks.
    // NOTE: We run the ROS loop in a separate thread as external calls such
    // as service callbacks to load controllers can block the (main) control loop
    ros::AsyncSpinner spinner(1);
    spinner.start();
    
    // Setup for the control loop.
    ros::Time prev_time = ros::Time::now();
    ros::Rate rate(10.0); // 50 Hz rate
    rate.sleep();
 
    // Blocks until shutdown signal recieved
    while (ros::ok())
    {
        // Basic bookkeeping to get the system time in order to compute the control period.
        const ros::Time     time   = ros::Time::now();
        const ros::Duration period = time - prev_time;
        prev_time = time;
 
        // Execution of the actual control loop.
        diffBot.read(time, period);
        // If needed, its possible to define transmissions in software by calling the 
        // transmission_interface::ActuatorToJointPositionInterface::propagate()
        // after reading the joint states.
        cm.update(time, period);
        // In case of software transmissions, use 
        // transmission_interface::JointToActuatorEffortHandle::propagate()
        // to convert from the joint space to the actuator space.
        diffBot.write(time, period);
        
        // All these steps keep getting repeated with the specified rate.
        rate.sleep();
    }
    return 0;
}