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[WIP] Enforce joint limits #223

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2 changes: 2 additions & 0 deletions ur_robot_driver/CMakeLists.txt
Original file line number Diff line number Diff line change
Expand Up @@ -115,6 +115,7 @@ add_dependencies(ur_robot_driver ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EX
add_library(ur_robot_driver_plugin
src/ros/dashboard_client_ros.cpp
src/ros/hardware_interface.cpp
src/ros/joint_limit_interface.cpp
)
target_link_libraries(ur_robot_driver_plugin ur_robot_driver ${catkin_LIBRARIES})
add_dependencies(ur_robot_driver_plugin ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
Expand All @@ -123,6 +124,7 @@ add_executable(ur_robot_driver_node
src/ros/dashboard_client_ros.cpp
src/ros/hardware_interface.cpp
src/ros/hardware_interface_node.cpp
src/ros/joint_limit_interface.cpp
)
target_link_libraries(ur_robot_driver_node ${catkin_LIBRARIES} ur_robot_driver)
add_dependencies(ur_robot_driver_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
Expand Down
33 changes: 33 additions & 0 deletions ur_robot_driver/include/ur_robot_driver/ros/hardware_interface.h
Original file line number Diff line number Diff line change
Expand Up @@ -45,8 +45,13 @@
#include <ur_msgs/SetIO.h>
#include "ur_msgs/SetSpeedSliderFraction.h"

#include <urdf/model.h>
#include <ur_controllers/speed_scaling_interface.h>
#include <ur_controllers/scaled_joint_command_interface.h>
#include <joint_limits_interface/joint_limits.h>
#include <joint_limits_interface/joint_limits_interface.h>
#include <joint_limits_interface/joint_limits_rosparam.h>
#include <joint_limits_interface/joint_limits_urdf.h>

#include "ur_robot_driver/ur/ur_driver.h"
#include <ur_robot_driver/ros/dashboard_client_ros.h>
Expand Down Expand Up @@ -156,6 +161,19 @@ class HardwareInterface : public hardware_interface::RobotHW
bool shouldResetControllers();

protected:
/*!
* \brief Applies joint limits & soft joint limits on position, velocity & effort defined in URDF / parameter server
*
*/
void registerJointLimits(ros::NodeHandle& robot_hw_nh, const hardware_interface::JointHandle& joint_handle_position,
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Does this function apply the limits or register the limits? I guess, the docstring needs to be adapted.

const hardware_interface::JointHandle& joint_handle_velocity, std::size_t joint_id);

/*!
* \brief Loads URDF model from robot_description parameter
*
* Requires robot_description paramter to be set on the parameter server
*/
void loadURDF(ros::NodeHandle& nh, std::string param_name);
/*!
* \brief Transforms force-torque measurements reported from the robot from base to tool frame.
*
Expand Down Expand Up @@ -223,6 +241,21 @@ class HardwareInterface : public hardware_interface::RobotHW
ur_controllers::ScaledVelocityJointInterface svj_interface_;
hardware_interface::ForceTorqueSensorInterface fts_interface_;

// Joint limits interfaces - Saturation
joint_limits_interface::PositionJointSaturationInterface pos_jnt_sat_interface_;
joint_limits_interface::VelocityJointSaturationInterface vel_jnt_sat_interface_;

// Joint limits interfaces - Soft limits
joint_limits_interface::PositionJointSoftLimitsInterface pos_jnt_soft_interface_;
joint_limits_interface::VelocityJointSoftLimitsInterface vel_jnt_soft_interface_;

// Copy of limits, in case we need them later in our control stack
std::vector<double> joint_position_lower_limits_;
std::vector<double> joint_position_upper_limits_;
std::vector<double> joint_velocity_limits_;

urdf::Model* urdf_model_;

vector6d_t joint_position_command_;
vector6d_t joint_velocity_command_;
vector6d_t joint_positions_;
Expand Down
22 changes: 18 additions & 4 deletions ur_robot_driver/src/ros/hardware_interface.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -61,6 +61,9 @@ HardwareInterface::HardwareInterface()
, pausing_state_(PausingState::RUNNING)
, pausing_ramp_up_increment_(0.01)
, controllers_initialized_(false)
, joint_position_lower_limits_(6)
, joint_position_upper_limits_(6)
, joint_velocity_limits_(6)
{
}

Expand All @@ -72,6 +75,9 @@ bool HardwareInterface::init(ros::NodeHandle& root_nh, ros::NodeHandle& robot_hw
std::string output_recipe_filename;
std::string input_recipe_filename;

// Load URDF file from parameter server
loadURDF(robot_hw_nh, "robot_description");
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This should probably be the root_nh


// The robot's IP address.
if (!robot_hw_nh.getParam("robot_ip", robot_ip_))
{
Expand Down Expand Up @@ -295,14 +301,18 @@ bool HardwareInterface::init(ros::NodeHandle& root_nh, ros::NodeHandle& robot_hw
&joint_velocities_[i], &joint_efforts_[i]));

// Create joint position control interface
pj_interface_.registerHandle(
hardware_interface::JointHandle(js_interface_.getHandle(joint_names_[i]), &joint_position_command_[i]));
vj_interface_.registerHandle(
hardware_interface::JointHandle(js_interface_.getHandle(joint_names_[i]), &joint_velocity_command_[i]));
hardware_interface::JointHandle joint_handle_position =
hardware_interface::JointHandle(js_interface_.getHandle(joint_names_[i]), &joint_position_command_[i]);
pj_interface_.registerHandle(joint_handle_position);
hardware_interface::JointHandle joint_handle_velocity =
hardware_interface::JointHandle(js_interface_.getHandle(joint_names_[i]), &joint_velocity_command_[i]);
vj_interface_.registerHandle(joint_handle_velocity);
spj_interface_.registerHandle(ur_controllers::ScaledJointHandle(
js_interface_.getHandle(joint_names_[i]), &joint_position_command_[i], &speed_scaling_combined_));
svj_interface_.registerHandle(ur_controllers::ScaledJointHandle(
js_interface_.getHandle(joint_names_[i]), &joint_velocity_command_[i], &speed_scaling_combined_));

registerJointLimits(robot_hw_nh, joint_handle_position, joint_handle_velocity, i);
}

speedsc_interface_.registerHandle(
Expand Down Expand Up @@ -519,10 +529,14 @@ void HardwareInterface::write(const ros::Time& time, const ros::Duration& period
{
if (position_controller_running_)
{
pos_jnt_soft_interface_.enforceLimits(period);
pos_jnt_sat_interface_.enforceLimits(period);
ur_driver_->writeJointCommand(joint_position_command_, comm::ControlMode::MODE_SERVOJ);
}
else if (velocity_controller_running_)
{
vel_jnt_soft_interface_.enforceLimits(period);
vel_jnt_sat_interface_.enforceLimits(period);
ur_driver_->writeJointCommand(joint_velocity_command_, comm::ControlMode::MODE_SPEEDJ);
}
else
Expand Down
187 changes: 187 additions & 0 deletions ur_robot_driver/src/ros/joint_limit_interface.cpp
Original file line number Diff line number Diff line change
@@ -0,0 +1,187 @@
/*********************************************************************
* Software License Agreement (BSD License)
*
* Copyright (c) 2015, PickNik LLC
* All rights reserved.
*
* 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 PickNik LLC 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.
*********************************************************************/

/* Author: Dave Coleman
Desc: Helper ros_control hardware interface that loads configurations
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I think a note where this file comes from and that you added modifications to it (if you did) might be nice to add here.

*/

#include "ur_robot_driver/ros/hardware_interface.h"

namespace ur_driver
{
void HardwareInterface::registerJointLimits(ros::NodeHandle& robot_hw_nh,
const hardware_interface::JointHandle& joint_handle_position,
const hardware_interface::JointHandle& joint_handle_velocity,
std::size_t joint_id)
{
// Default values
joint_position_lower_limits_[joint_id] = -std::numeric_limits<double>::max();
joint_position_upper_limits_[joint_id] = std::numeric_limits<double>::max();
joint_velocity_limits_[joint_id] = std::numeric_limits<double>::max();

// Limits datastructures
joint_limits_interface::JointLimits joint_limits; // Position
joint_limits_interface::SoftJointLimits soft_limits; // Soft Position
bool has_joint_limits = false;
bool has_soft_limits = false;

// Get limits from URDF
if (urdf_model_ == nullptr)
{
ROS_WARN_STREAM("No URDF model loaded, unable to get joint limits");
return;
}

// Get limits from URDF
urdf::JointConstSharedPtr urdf_joint = urdf_model_->getJoint(joint_names_[joint_id]);

// Get main joint limits
if (urdf_joint == nullptr)
{
ROS_ERROR_STREAM("URDF joint not found " << joint_names_[joint_id]);
return;
}

// Get limits from URDF
if (joint_limits_interface::getJointLimits(urdf_joint, joint_limits))
{
has_joint_limits = true;
ROS_DEBUG_STREAM("Joint " << joint_names_[joint_id] << " has URDF position limits [" << joint_limits.min_position
<< ", " << joint_limits.max_position << "]");
if (joint_limits.has_velocity_limits)
ROS_DEBUG_STREAM("Joint " << joint_names_[joint_id] << " has URDF velocity limit [" << joint_limits.max_velocity
<< "]");
}
else
{
if (urdf_joint->type != urdf::Joint::CONTINUOUS)
ROS_WARN_STREAM("No URDF limits are configured for joint " << joint_names_[joint_id]);
}

// Get limits from ROS param
if (joint_limits_interface::getJointLimits(joint_names_[joint_id], robot_hw_nh, joint_limits))
{
has_joint_limits = true;
ROS_DEBUG_STREAM("Joint " << joint_names_[joint_id] << " has rosparam position limits ["
<< joint_limits.min_position << ", " << joint_limits.max_position << "]");
if (joint_limits.has_velocity_limits)
ROS_DEBUG_STREAM("Joint " << joint_names_[joint_id] << " has rosparam velocity limit ["
<< joint_limits.max_velocity << "]");
} // the else debug message provided internally by joint_limits_interface

// Get soft limits from URDF
if (joint_limits_interface::getSoftJointLimits(urdf_joint, soft_limits))
{
has_soft_limits = true;
ROS_DEBUG_STREAM("Joint " << joint_names_[joint_id] << " has soft joint limits.");
}
else
{
ROS_DEBUG_STREAM("Joint " << joint_names_[joint_id]
<< " does not have soft joint "
"limits");
}

// Quit we we haven't found any limits in URDF or rosparam server
if (!has_joint_limits)
{
return;
}

// Copy position limits if available
if (joint_limits.has_position_limits)
{
// Slighly reduce the joint limits to prevent floating point errors
joint_limits.min_position += std::numeric_limits<double>::epsilon();
joint_limits.max_position -= std::numeric_limits<double>::epsilon();

joint_position_lower_limits_[joint_id] = joint_limits.min_position;
joint_position_upper_limits_[joint_id] = joint_limits.max_position;
}

// Copy velocity limits if available
if (joint_limits.has_velocity_limits)
{
joint_velocity_limits_[joint_id] = joint_limits.max_velocity;
}

if (has_soft_limits) // Use soft limits
{
ROS_DEBUG_STREAM("Using soft saturation limits");
const joint_limits_interface::PositionJointSoftLimitsHandle soft_handle_position(joint_handle_position,
joint_limits, soft_limits);
pos_jnt_soft_interface_.registerHandle(soft_handle_position);
const joint_limits_interface::VelocityJointSoftLimitsHandle soft_handle_velocity(joint_handle_velocity,
joint_limits, soft_limits);
vel_jnt_soft_interface_.registerHandle(soft_handle_velocity);
}
else // Use saturation limits
{
ROS_DEBUG_STREAM("Using saturation limits (not soft limits)");

const joint_limits_interface::PositionJointSaturationHandle sat_handle_position(joint_handle_position,
joint_limits);
pos_jnt_sat_interface_.registerHandle(sat_handle_position);

const joint_limits_interface::VelocityJointSaturationHandle sat_handle_velocity(joint_handle_velocity,
joint_limits);
vel_jnt_sat_interface_.registerHandle(sat_handle_velocity);
}
}

void HardwareInterface::loadURDF(ros::NodeHandle& nh, std::string param_name)
{
std::string urdf_string;
urdf_model_ = new urdf::Model();

// search and wait for robot_description on param server
while (urdf_string.empty() && ros::ok())
{
std::string search_param_name;
if (nh.searchParam(param_name, search_param_name))
{
ROS_INFO_STREAM("Waiting for model URDF on the ROS param server at location: " << nh.getNamespace()
<< search_param_name);
nh.getParam(search_param_name, urdf_string);
}

usleep(100000);
}

if (!urdf_model_->initString(urdf_string))
ROS_ERROR_STREAM("Unable to load URDF model");
else
ROS_DEBUG_STREAM("Received URDF from param server");
}
} // namespace ur_driver