gripper_controller_handle.h

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/* Author: Michael Ferguson, Ioan Sucan, E. Gil Jones */
 
#pragma once
 
#include <moveit_simple_controller_manager/action_based_controller_handle.h>
#include <control_msgs/GripperCommandAction.h>
#include <set>
 
namespace moveit_simple_controller_manager
{
/*
 * This is an interface for a gripper using control_msgs/GripperCommandAction
 * action interface (single DOF).
 */
class GripperControllerHandle : public ActionBasedControllerHandle<control_msgs::GripperCommandAction>
{
public:
  /* Topics will map to name/ns/goal, name/ns/result, etc */
  GripperControllerHandle(const std::string& name, const std::string& ns, const double max_effort = 0.0)
    : ActionBasedControllerHandle<control_msgs::GripperCommandAction>(name, ns)
    , allow_failure_(false)
    , parallel_jaw_gripper_(false)
    , max_effort_(max_effort)
  {
  }
 
  bool sendTrajectory(const moveit_msgs::RobotTrajectory& trajectory) override
  {
    ROS_DEBUG_STREAM_NAMED("GripperController", "Received new trajectory for " << name_);
 
    if (!controller_action_client_)
      return false;
 
    if (!trajectory.multi_dof_joint_trajectory.points.empty())
    {
      ROS_ERROR_NAMED("GripperController", "Gripper cannot execute multi-dof trajectories.");
      return false;
    }
 
    if (trajectory.joint_trajectory.points.empty())
    {
      ROS_ERROR_NAMED("GripperController", "GripperController requires at least one joint trajectory point.");
      return false;
    }
 
    if (trajectory.joint_trajectory.points.size() > 1)
    {
      ROS_DEBUG_STREAM_NAMED("GripperController", "Trajectory: " << trajectory.joint_trajectory);
    }
 
    if (trajectory.joint_trajectory.joint_names.empty())
    {
      ROS_ERROR_NAMED("GripperController", "No joint names specified");
      return false;
    }
 
    std::vector<std::size_t> gripper_joint_indexes;
    for (std::size_t i = 0; i < trajectory.joint_trajectory.joint_names.size(); ++i)
    {
      if (command_joints_.find(trajectory.joint_trajectory.joint_names[i]) != command_joints_.end())
      {
        gripper_joint_indexes.push_back(i);
        if (!parallel_jaw_gripper_)
          break;
      }
    }
 
    if (gripper_joint_indexes.empty())
    {
      ROS_WARN_NAMED("GripperController", "No command_joint was specified for the MoveIt controller gripper handle. \
                      Please see GripperControllerHandle::addCommandJoint() and \
                      GripperControllerHandle::setCommandJoint(). Assuming index 0.");
      gripper_joint_indexes.push_back(0);
    }
 
    // goal to be sent
    control_msgs::GripperCommandGoal goal;
    goal.command.position = 0.0;
 
    // send last point
    int tpoint = trajectory.joint_trajectory.points.size() - 1;
    ROS_DEBUG_NAMED("GripperController", "Sending command from trajectory point %d", tpoint);
 
    // fill in goal from last point
    for (std::size_t idx : gripper_joint_indexes)
    {
      if (trajectory.joint_trajectory.points[tpoint].positions.size() <= idx)
      {
        ROS_ERROR_NAMED("GripperController", "GripperController expects a joint trajectory with one \
                         point that specifies at least the position of joint \
                         '%s', but insufficient positions provided",
                        trajectory.joint_trajectory.joint_names[idx].c_str());
        return false;
      }
      goal.command.position += trajectory.joint_trajectory.points[tpoint].positions[idx];
 
      if (trajectory.joint_trajectory.points[tpoint].effort.size() > idx)
      {
        goal.command.max_effort = trajectory.joint_trajectory.points[tpoint].effort[idx];
      }
      else
      {
        goal.command.max_effort = max_effort_;
      }
    }
 
    controller_action_client_->sendGoal(
        goal, [this](const auto& state, const auto& result) { controllerDoneCallback(state, result); },
        [this] { controllerActiveCallback(); }, [this](const auto& feedback) { controllerFeedbackCallback(feedback); });
 
    done_ = false;
    last_exec_ = moveit_controller_manager::ExecutionStatus::RUNNING;
    return true;
  }
 
  void setCommandJoint(const std::string& name)
  {
    command_joints_.clear();
    addCommandJoint(name);
  }
 
  void addCommandJoint(const std::string& name)
  {
    command_joints_.insert(name);
  }
 
  void allowFailure(bool allow)
  {
    allow_failure_ = allow;
  }
 
  void setParallelJawGripper(const std::string& left, const std::string& right)
  {
    addCommandJoint(left);
    addCommandJoint(right);
    parallel_jaw_gripper_ = true;
  }
 
private:
  void controllerDoneCallback(const actionlib::SimpleClientGoalState& state,
                              const control_msgs::GripperCommandResultConstPtr& /* result */)
  {
    if (state == actionlib::SimpleClientGoalState::ABORTED && allow_failure_)
      finishControllerExecution(actionlib::SimpleClientGoalState::SUCCEEDED);
    else
      finishControllerExecution(state);
  }
 
  void controllerActiveCallback()
  {
    ROS_DEBUG_STREAM_NAMED("GripperController", name_ << " started execution");
  }
 
  void controllerFeedbackCallback(const control_msgs::GripperCommandFeedbackConstPtr& /* feedback */)
  {
  }
 
  /*
   * Some gripper drivers may indicate a failure if they do not close all the way when
   * an object is in the gripper.
   */
  bool allow_failure_;
 
  /*
   * A common setup is where there are two joints that each move
   * half the overall distance. Thus, the command to the gripper
   * should be the sum of the two joint distances.
   *
   * When this is set, command_joints_ should be of size 2,
   * and the command will be the sum of the two joints.
   */
  bool parallel_jaw_gripper_;
 
  /*
   * The ``max_effort`` used in the GripperCommand message when no ``max_effort`` was
   * specified in the requested trajectory. Defaults to ``0.0``.
   */
  double max_effort_;
 
  /*
   * A GripperCommand message has only a single float64 for the
   * "command", thus only a single joint angle can be sent -- however,
   * due to the complexity of making grippers look correct in a URDF,
   * they typically have >1 joints. The "command_joint" is the joint
   * whose position value will be sent in the GripperCommand action. A
   * set of names is provided for acceptable joint names. If any of
   * the joints specified is found, the value corresponding to that
   * joint is considered the command.
   */
  std::set<std::string> command_joints_;
};
 
}  // end namespace moveit_simple_controller_manager