hardware_interface_adapter.h

Go to the documentation of this file.

// Copyright (C) 2013, PAL Robotics S.L.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
//   * Neither the name of PAL Robotics S.L. nor the names of its
//     contributors may be used to endorse or promote products derived from
//     this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.


#ifndef JOINT_TRAJECTORY_CONTROLLER_HARDWARE_INTERFACE_ADAPTER_H
#define JOINT_TRAJECTORY_CONTROLLER_HARDWARE_INTERFACE_ADAPTER_H

#include <cassert>
#include <string>
#include <vector>

#include <boost/shared_ptr.hpp>

#include <ros/node_handle.h>
#include <ros/time.h>

#include <control_toolbox/pid.h>
#include <hardware_interface/joint_command_interface.h>

template <class HardwareInterface, class State>
class HardwareInterfaceAdapter
{
public:
  bool init(std::vector<typename HardwareInterface::ResourceHandleType>& joint_handles, ros::NodeHandle& controller_nh)
  {
    return false;
  }

  void starting(const ros::Time& time) {}
  void stopping(const ros::Time& time) {}

  void updateCommand(const ros::Time&     time,
                     const ros::Duration& period,
                     const State&         desired_state,
                     const State&         state_error) {}
};

template <class State>
class HardwareInterfaceAdapter<hardware_interface::PositionJointInterface, State>
{
public:
  HardwareInterfaceAdapter() : joint_handles_ptr_(0) {}

  bool init(std::vector<hardware_interface::JointHandle>& joint_handles, ros::NodeHandle& controller_nh)
  {
    // Store pointer to joint handles
    joint_handles_ptr_ = &joint_handles;

    return true;
  }

  void starting(const ros::Time& time) {}
  void stopping(const ros::Time& time) {}

  void updateCommand(const ros::Time&     /*time*/,
                     const ros::Duration& /*period*/,
                     const State&         desired_state,
                     const State&         /*state_error*/)
  {
    // Forward desired position to command
    const unsigned int n_joints = joint_handles_ptr_->size();
    for (unsigned int i = 0; i < n_joints; ++i) {(*joint_handles_ptr_)[i].setCommand(desired_state.position[i]);}
  }

private:
  std::vector<hardware_interface::JointHandle>* joint_handles_ptr_;
};

template <class State>
class HardwareInterfaceAdapter<hardware_interface::EffortJointInterface, State>
{
public:
  HardwareInterfaceAdapter() : joint_handles_ptr_(0) {}

  bool init(std::vector<hardware_interface::JointHandle>& joint_handles, ros::NodeHandle& controller_nh)
  {
    // Store pointer to joint handles
    joint_handles_ptr_ = &joint_handles;

    // Initialize PIDs
    pids_.resize(joint_handles.size());
    for (unsigned int i = 0; i < pids_.size(); ++i)
    {
      // Node handle to PID gains
      ros::NodeHandle joint_nh(controller_nh, std::string("gains/") + joint_handles[i].getName());

      // Init PID gains from ROS parameter server
      pids_[i].reset(new control_toolbox::Pid());
      if (!pids_[i]->init(joint_nh))
      {
        ROS_WARN_STREAM("Failed to initialize PID gains from ROS parameter server.");
        return false;
      }
    }

    return true;
  }

  void starting(const ros::Time& time)
  {
    if (!joint_handles_ptr_) {return;}

    // Reset PIDs, zero effort commands
    for (unsigned int i = 0; i < pids_.size(); ++i)
    {
      pids_[i]->reset();
      (*joint_handles_ptr_)[i].setCommand(0.0);
    }
  }

  void stopping(const ros::Time& time) {}

  void updateCommand(const ros::Time&     /*time*/,
                     const ros::Duration& period,
                     const State&         /*desired_state*/,
                     const State&         state_error)
  {
    const unsigned int n_joints = joint_handles_ptr_->size();

    // Preconditions
    if (!joint_handles_ptr_) {return;}
    assert(n_joints == state_error.position.size());
    assert(n_joints == state_error.velocity.size());

    // Update PIDs
    for (unsigned int i = 0; i < n_joints; ++i)
    {
      const double command = pids_[i]->computeCommand(state_error.position[i], state_error.velocity[i], period);
      (*joint_handles_ptr_)[i].setCommand(command);
    }
  }

private:
  typedef boost::shared_ptr<control_toolbox::Pid> PidPtr;
  std::vector<PidPtr> pids_;

  std::vector<hardware_interface::JointHandle>* joint_handles_ptr_;
};

#endif // header guard