joint_velocity_controller.cpp

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#include "robot_mechanism_controllers/joint_velocity_controller.h"
#include "pluginlib/class_list_macros.h"

PLUGINLIB_EXPORT_CLASS( controller::JointVelocityController, pr2_controller_interface::Controller)

using namespace std;

namespace controller {

JointVelocityController::JointVelocityController()
: joint_state_(NULL), command_(0), robot_(NULL), last_time_(0), loop_count_(0)
{
}

JointVelocityController::~JointVelocityController()
{
  sub_command_.shutdown();
}

bool JointVelocityController::init(pr2_mechanism_model::RobotState *robot, const std::string &joint_name,
                                   const control_toolbox::Pid &pid)
{
  assert(robot);
  robot_ = robot;
  last_time_ = robot->getTime();

  joint_state_ = robot_->getJointState(joint_name);
  if (!joint_state_)
  {
    ROS_ERROR("JointVelocityController could not find joint named \"%s\"\n",
              joint_name.c_str());
    return false;
  }

  pid_controller_ = pid;

  return true;
}

bool JointVelocityController::init(pr2_mechanism_model::RobotState *robot, ros::NodeHandle &n)
{
  assert(robot);
  node_ = n;
  robot_ = robot;

  std::string joint_name;
  if (!node_.getParam("joint", joint_name)) {
    ROS_ERROR("No joint given (namespace: %s)", node_.getNamespace().c_str());
    return false;
  }
  if (!(joint_state_ = robot->getJointState(joint_name)))
  {
    ROS_ERROR("Could not find joint \"%s\" (namespace: %s)",
              joint_name.c_str(), node_.getNamespace().c_str());
    return false;
  }

  if (!pid_controller_.init(ros::NodeHandle(node_, "pid")))
    return false;

  controller_state_publisher_.reset(
    new realtime_tools::RealtimePublisher<pr2_controllers_msgs::JointControllerState>
    (node_, "state", 1));

  sub_command_ = node_.subscribe<std_msgs::Float64>("command", 1, &JointVelocityController::setCommandCB, this);

  return true;
}


void JointVelocityController::setGains(const double &p, const double &i, const double &d, const double &i_max, const double &i_min)
{
  pid_controller_.setGains(p,i,d,i_max,i_min);

}

void JointVelocityController::getGains(double &p, double &i, double &d, double &i_max, double &i_min)
{
  pid_controller_.getGains(p,i,d,i_max,i_min);
}

std::string JointVelocityController::getJointName()
{
  return joint_state_->joint_->name;
}

// Set the joint velocity command
void JointVelocityController::setCommand(double cmd)
{
  command_ = cmd;
}

// Return the current velocity command
void JointVelocityController::getCommand(double  & cmd)
{
  cmd = command_;
}

void JointVelocityController::update()
{
  assert(robot_ != NULL);
  ros::Time time = robot_->getTime();

  double error = command_ - joint_state_->velocity_;
  dt_ = time - last_time_;
  double command = pid_controller_.computeCommand(error, dt_);
  joint_state_->commanded_effort_ += command;

  if(loop_count_ % 10 == 0)
  {
    if(controller_state_publisher_ && controller_state_publisher_->trylock())
    {
      controller_state_publisher_->msg_.header.stamp = time;
      controller_state_publisher_->msg_.set_point = command_;
      controller_state_publisher_->msg_.process_value = joint_state_->velocity_;
      controller_state_publisher_->msg_.error = error;
      controller_state_publisher_->msg_.time_step = dt_.toSec();
      controller_state_publisher_->msg_.command = command;

      double dummy;
      getGains(controller_state_publisher_->msg_.p,
               controller_state_publisher_->msg_.i,
               controller_state_publisher_->msg_.d,
               controller_state_publisher_->msg_.i_clamp,
               dummy);
      controller_state_publisher_->unlockAndPublish();
    }
  }
  loop_count_++;

  last_time_ = time;
}

void JointVelocityController::setCommandCB(const std_msgs::Float64ConstPtr& msg)
{
  command_ = msg->data;
}

} // namespace