diff_drive_base.h

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// Author: Michael Ferguson

#ifndef ROBOT_CONTROLLERS_DIFF_DRIVE_BASE_H
#define ROBOT_CONTROLLERS_DIFF_DRIVE_BASE_H

#include <string>
#include <boost/shared_ptr.hpp>
#include <boost/thread/mutex.hpp>

#include <ros/ros.h>
#include <robot_controllers_interface/controller.h>
#include <robot_controllers_interface/controller_manager.h>
#include <robot_controllers_interface/joint_handle.h>
#include <tf/transform_broadcaster.h>

#include <geometry_msgs/Twist.h>
#include <nav_msgs/Odometry.h>
#include <sensor_msgs/LaserScan.h>

namespace robot_controllers
{

class DiffDriveBaseController : public Controller
{
public:
  DiffDriveBaseController();
  virtual ~DiffDriveBaseController() {}

  virtual int init(ros::NodeHandle& nh, ControllerManager* manager);

  virtual bool start();

  virtual bool stop(bool force);

  virtual bool reset();

  virtual void update(const ros::Time& now, const ros::Duration& dt);

  virtual std::string getType()
  {
    return "robot_controllers/DiffDriveBaseController";
  }

  virtual std::vector<std::string> getCommandedNames();

  virtual std::vector<std::string> getClaimedNames();

  void command(const geometry_msgs::TwistConstPtr& msg);

private:
  bool initialized_;
  ControllerManager* manager_;

  void publishCallback(const ros::TimerEvent& event);
  void scanCallback(const sensor_msgs::LaserScanConstPtr& scan);

  // Set base wheel speeds in m/s
  void setCommand(float left, float right);

  JointHandlePtr left_;
  JointHandlePtr right_;

  double track_width_;
  double radians_per_meter_;
  double theta_;

  double wheel_rotating_threshold_;  
  double rotating_threshold_;  
  double moving_threshold_;    

  double max_velocity_x_;
  double max_velocity_r_;
  double max_acceleration_x_;
  double max_acceleration_r_;

  // Laser can provide additional safety limits on velocity
  double safety_scaling_;
  double safety_scaling_distance_;
  double robot_width_;
  ros::Time last_laser_scan_;

  // These are the inputs from the ROS topic
  boost::mutex command_mutex_;
  double desired_x_;
  double desired_r_;

  // These are from controller update
  float last_sent_x_;
  float last_sent_r_;

  float left_last_position_;
  float right_last_position_;
  double left_last_timestamp_;
  double right_last_timestamp_;

  ros::Time last_command_;
  ros::Time last_update_;
  ros::Duration timeout_;

  boost::mutex odom_mutex_;
  nav_msgs::Odometry odom_;
  ros::Publisher odom_pub_;
  ros::Timer odom_timer_;
  ros::Subscriber cmd_sub_, scan_sub_;

  boost::shared_ptr<tf::TransformBroadcaster> broadcaster_;
  bool publish_tf_;

  bool enabled_;
  bool ready_;
};

typedef boost::shared_ptr<DiffDriveBaseController> DiffDriveBaseControllerPtr;

}  // namespace robot_controllers

#endif  // ROBOT_CONTROLLERS_DIFF_DRIVE_BASE_H