forward_joint_group_command_controller.h

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#ifndef FORWARD_COMMAND_CONTROLLER_FORWARD_JOINT_GROUP_COMMAND_CONTROLLER_H
#define FORWARD_COMMAND_CONTROLLER_FORWARD_JOINT_GROUP_COMMAND_CONTROLLER_H

#include <vector>
#include <string>

#include <ros/node_handle.h>
#include <hardware_interface/joint_command_interface.h>
#include <controller_interface/controller.h>
#include <std_msgs/Float64MultiArray.h>
#include <realtime_tools/realtime_buffer.h>


namespace forward_command_controller
{

template <class T>
class ForwardJointGroupCommandController: public controller_interface::Controller<T>
{
public:
  ForwardJointGroupCommandController() {}
  ~ForwardJointGroupCommandController() {sub_command_.shutdown();}

  bool init(T* hw, ros::NodeHandle &n)
  {
    // List of controlled joints
    std::string param_name = "joints";
    if(!n.getParam(param_name, joint_names_))
    {
      ROS_ERROR_STREAM("Failed to getParam '" << param_name << "' (namespace: " << n.getNamespace() << ").");
      return false;
    }
    n_joints_ = joint_names_.size();

    if(n_joints_ == 0){
      ROS_ERROR_STREAM("List of joint names is empty.");
      return false;
    }
    for(unsigned int i=0; i<n_joints_; i++)
    {
      try
      {
        joints_.push_back(hw->getHandle(joint_names_[i]));  
      }
      catch (const hardware_interface::HardwareInterfaceException& e)
      {
        ROS_ERROR_STREAM("Exception thrown: " << e.what());
        return false;
      }
    }

    commands_buffer_.writeFromNonRT(std::vector<double>(n_joints_, 0.0));

    sub_command_ = n.subscribe<std_msgs::Float64MultiArray>("command", 1, &ForwardJointGroupCommandController::commandCB, this);
    return true;
  }

  void starting(const ros::Time& time);
  void update(const ros::Time& /*time*/, const ros::Duration& /*period*/)
  {
    std::vector<double> & commands = *commands_buffer_.readFromRT();
    for(unsigned int i=0; i<n_joints_; i++)
    {  joints_[i].setCommand(commands[i]);  }
  }

  std::vector< std::string > joint_names_;
  std::vector< hardware_interface::JointHandle > joints_;
  realtime_tools::RealtimeBuffer<std::vector<double> > commands_buffer_;
  unsigned int n_joints_;

private:
  ros::Subscriber sub_command_;
  void commandCB(const std_msgs::Float64MultiArrayConstPtr& msg) 
  {
    if(msg->data.size()!=n_joints_)
    { 
      ROS_ERROR_STREAM("Dimension of command (" << msg->data.size() << ") does not match number of joints (" << n_joints_ << ")! Not executing!");
      return; 
    }
    commands_buffer_.writeFromNonRT(msg->data);
  }
};

}

#endif