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servo_calcs.cpp
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servo_calcs.cpp
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/*******************************************************************************
* BSD 3-Clause License
*
* Copyright (c) 2019, Los Alamos National Security, 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 the copyright holder 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 HOLDER 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.
*******************************************************************************/
/* Title : servo_calcs.cpp
* Project : moveit_servo
* Created : 1/11/2019
* Author : Brian O'Neil, Andy Zelenak, Blake Anderson
*/
#include <cassert>
#include <std_msgs/Bool.h>
#include <std_msgs/Float64MultiArray.h>
#include <moveit_servo/make_shared_from_pool.h>
#include <moveit_servo/servo_calcs.h>
static const std::string LOGNAME = "servo_calcs";
constexpr size_t ROS_LOG_THROTTLE_PERIOD = 30; // Seconds to throttle logs inside loops
namespace moveit_servo
{
namespace
{
// Helper function for detecting zeroed message
bool isNonZero(const geometry_msgs::TwistStamped& msg)
{
return msg.twist.linear.x != 0.0 || msg.twist.linear.y != 0.0 || msg.twist.linear.z != 0.0 ||
msg.twist.angular.x != 0.0 || msg.twist.angular.y != 0.0 || msg.twist.angular.z != 0.0;
}
// Helper function for detecting zeroed message
bool isNonZero(const control_msgs::JointJog& msg)
{
bool all_zeros = true;
for (double delta : msg.velocities)
{
all_zeros &= (delta == 0.0);
};
return !all_zeros;
}
// Helper function for converting Eigen::Isometry3d to geometry_msgs/TransformStamped
geometry_msgs::TransformStamped convertIsometryToTransform(const Eigen::Isometry3d& eigen_tf,
const std::string& parent_frame,
const std::string& child_frame)
{
geometry_msgs::TransformStamped output = tf2::eigenToTransform(eigen_tf);
output.header.frame_id = parent_frame;
output.child_frame_id = child_frame;
return output;
}
} // namespace
// Constructor for the class that handles servoing calculations
ServoCalcs::ServoCalcs(ros::NodeHandle& nh, ServoParameters& parameters,
const planning_scene_monitor::PlanningSceneMonitorPtr& planning_scene_monitor)
: nh_(nh)
, parameters_(parameters)
, planning_scene_monitor_(planning_scene_monitor)
, stop_requested_(true)
, paused_(false)
{
// MoveIt Setup
current_state_ = planning_scene_monitor_->getStateMonitor()->getCurrentState();
joint_model_group_ = current_state_->getJointModelGroup(parameters_.move_group_name);
prev_joint_velocity_ = Eigen::ArrayXd::Zero(joint_model_group_->getActiveJointModels().size());
// Subscribe to command topics
twist_stamped_sub_ =
nh_.subscribe(parameters_.cartesian_command_in_topic, ROS_QUEUE_SIZE, &ServoCalcs::twistStampedCB, this);
joint_cmd_sub_ = nh_.subscribe(parameters_.joint_command_in_topic, ROS_QUEUE_SIZE, &ServoCalcs::jointCmdCB, this);
// ROS Server for allowing drift in some dimensions
drift_dimensions_server_ = nh_.advertiseService(ros::names::append(nh_.getNamespace(), "change_drift_dimensions"),
&ServoCalcs::changeDriftDimensions, this);
// ROS Server for changing the control dimensions
control_dimensions_server_ = nh_.advertiseService(ros::names::append(nh_.getNamespace(), "change_control_dimensions"),
&ServoCalcs::changeControlDimensions, this);
// ROS Server to reset the status, e.g. so the arm can move again after a collision
reset_servo_status_ = nh_.advertiseService(ros::names::append(nh_.getNamespace(), "reset_servo_status"),
&ServoCalcs::resetServoStatus, this);
// Publish and Subscribe to internal namespace topics
ros::NodeHandle internal_nh(nh_, "internal");
collision_velocity_scale_sub_ =
internal_nh.subscribe("collision_velocity_scale", ROS_QUEUE_SIZE, &ServoCalcs::collisionVelocityScaleCB, this);
worst_case_stop_time_pub_ = internal_nh.advertise<std_msgs::Float64>("worst_case_stop_time", ROS_QUEUE_SIZE);
// Publish freshly-calculated joints to the robot.
// Put the outgoing msg in the right format (trajectory_msgs/JointTrajectory or std_msgs/Float64MultiArray).
if (parameters_.command_out_type == "trajectory_msgs/JointTrajectory")
outgoing_cmd_pub_ = nh_.advertise<trajectory_msgs::JointTrajectory>(parameters_.command_out_topic, ROS_QUEUE_SIZE);
else if (parameters_.command_out_type == "std_msgs/Float64MultiArray")
outgoing_cmd_pub_ = nh_.advertise<std_msgs::Float64MultiArray>(parameters_.command_out_topic, ROS_QUEUE_SIZE);
// Publish status
status_pub_ = nh_.advertise<std_msgs::Int8>(parameters_.status_topic, ROS_QUEUE_SIZE);
internal_joint_state_.name = joint_model_group_->getActiveJointModelNames();
num_joints_ = internal_joint_state_.name.size();
internal_joint_state_.position.resize(num_joints_);
internal_joint_state_.velocity.resize(num_joints_);
// A map for the indices of incoming joint commands
for (std::size_t i = 0; i < num_joints_; ++i)
{
joint_state_name_map_[internal_joint_state_.name[i]] = i;
}
// Low-pass filters for the joint positions
for (size_t i = 0; i < num_joints_; ++i)
{
position_filters_.emplace_back(parameters_.low_pass_filter_coeff);
}
// A matrix of all zeros is used to check whether matrices have been initialized
Eigen::Matrix3d empty_matrix;
empty_matrix.setZero();
tf_moveit_to_ee_frame_ = empty_matrix;
tf_moveit_to_robot_cmd_frame_ = empty_matrix;
}
ServoCalcs::~ServoCalcs()
{
stop();
}
void ServoCalcs::start()
{
// Stop the thread if we are currently running
stop();
// We will update last_sent_command_ every time we start servo
auto initial_joint_trajectory = moveit::util::make_shared_from_pool<trajectory_msgs::JointTrajectory>();
// When a joint_trajectory_controller receives a new command, a stamp of 0 indicates "begin immediately"
// See http://wiki.ros.org/joint_trajectory_controller#Trajectory_replacement
initial_joint_trajectory->header.stamp = ros::Time(0);
initial_joint_trajectory->header.frame_id = parameters_.planning_frame;
initial_joint_trajectory->joint_names = internal_joint_state_.name;
trajectory_msgs::JointTrajectoryPoint point;
point.time_from_start = ros::Duration(parameters_.publish_period);
if (parameters_.publish_joint_positions)
planning_scene_monitor_->getStateMonitor()->getCurrentState()->copyJointGroupPositions(joint_model_group_,
point.positions);
if (parameters_.publish_joint_velocities)
{
std::vector<double> velocity(num_joints_);
point.velocities = velocity;
}
if (parameters_.publish_joint_accelerations)
{
// I do not know of a robot that takes acceleration commands.
// However, some controllers check that this data is non-empty.
// Send all zeros, for now.
std::vector<double> acceleration(num_joints_);
point.accelerations = acceleration;
}
initial_joint_trajectory->points.push_back(point);
last_sent_command_ = initial_joint_trajectory;
current_state_ = planning_scene_monitor_->getStateMonitor()->getCurrentState();
tf_moveit_to_ee_frame_ = current_state_->getGlobalLinkTransform(parameters_.planning_frame).inverse() *
current_state_->getGlobalLinkTransform(parameters_.ee_frame_name);
tf_moveit_to_robot_cmd_frame_ = current_state_->getGlobalLinkTransform(parameters_.planning_frame).inverse() *
current_state_->getGlobalLinkTransform(parameters_.robot_link_command_frame);
stop_requested_ = false;
thread_ = std::thread([this] { mainCalcLoop(); });
new_input_cmd_ = false;
}
void ServoCalcs::stop()
{
// Request stop
stop_requested_ = true;
// Notify condition variable in case the thread is blocked on it
{
// scope so the mutex is unlocked after so the thread can continue
// and therefore be joinable
const std::lock_guard<std::mutex> lock(input_mutex_);
new_input_cmd_ = false;
input_cv_.notify_all();
}
// Join the thread
if (thread_.joinable())
{
thread_.join();
}
}
void ServoCalcs::mainCalcLoop()
{
ros::Rate rate(1.0 / parameters_.publish_period);
while (ros::ok() && !stop_requested_)
{
// lock the input state mutex
std::unique_lock<std::mutex> input_lock(input_mutex_);
// low latency mode -- begin calculations as soon as a new command is received.
if (parameters_.low_latency_mode)
{
input_cv_.wait(input_lock, [this] { return (new_input_cmd_ || stop_requested_); });
}
// reset new_input_cmd_ flag
new_input_cmd_ = false;
// run servo calcs
const auto start_time = ros::Time::now();
calculateSingleIteration();
const auto run_duration = ros::Time::now() - start_time;
// Log warning when the run duration was longer than the period
if (run_duration.toSec() > parameters_.publish_period)
{
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME,
"run_duration: " << run_duration.toSec() << " (" << parameters_.publish_period
<< ")");
}
// normal mode, unlock input mutex and wait for the period of the loop
if (!parameters_.low_latency_mode)
{
input_lock.unlock();
rate.sleep();
}
}
}
void ServoCalcs::calculateSingleIteration()
{
// Publish status each loop iteration
auto status_msg = moveit::util::make_shared_from_pool<std_msgs::Int8>();
status_msg->data = static_cast<int8_t>(status_);
status_pub_.publish(status_msg);
// Always update the joints and end-effector transform for 2 reasons:
// 1) in case the getCommandFrameTransform() method is being used
// 2) so the low-pass filters are up to date and don't cause a jump
updateJoints();
// Update from latest state
current_state_ = planning_scene_monitor_->getStateMonitor()->getCurrentState();
if (latest_twist_stamped_)
twist_stamped_cmd_ = *latest_twist_stamped_;
if (latest_joint_cmd_)
joint_servo_cmd_ = *latest_joint_cmd_;
// Check for stale cmds
twist_command_is_stale_ =
((ros::Time::now() - latest_twist_command_stamp_) >= ros::Duration(parameters_.incoming_command_timeout));
joint_command_is_stale_ =
((ros::Time::now() - latest_joint_command_stamp_) >= ros::Duration(parameters_.incoming_command_timeout));
have_nonzero_twist_stamped_ = latest_nonzero_twist_stamped_;
have_nonzero_joint_command_ = latest_nonzero_joint_cmd_;
// Get the transform from MoveIt planning frame to servoing command frame
// Calculate this transform to ensure it is available via C++ API
// We solve (planning_frame -> base -> robot_link_command_frame)
// by computing (base->planning_frame)^-1 * (base->robot_link_command_frame)
tf_moveit_to_robot_cmd_frame_ = current_state_->getGlobalLinkTransform(parameters_.planning_frame).inverse() *
current_state_->getGlobalLinkTransform(parameters_.robot_link_command_frame);
// Calculate the transform from MoveIt planning frame to End Effector frame
// Calculate this transform to ensure it is available via C++ API
tf_moveit_to_ee_frame_ = current_state_->getGlobalLinkTransform(parameters_.planning_frame).inverse() *
current_state_->getGlobalLinkTransform(parameters_.ee_frame_name);
have_nonzero_command_ = have_nonzero_twist_stamped_ || have_nonzero_joint_command_;
// Don't end this function without updating the filters
updated_filters_ = false;
// If paused or while waiting for initial servo commands, just keep the low-pass filters up to date with current
// joints so a jump doesn't occur when restarting
if (wait_for_servo_commands_ || paused_)
{
resetLowPassFilters(original_joint_state_);
// Check if there are any new commands with valid timestamp
wait_for_servo_commands_ =
twist_stamped_cmd_.header.stamp == ros::Time(0.) && joint_servo_cmd_.header.stamp == ros::Time(0.);
// Early exit
return;
}
// If not waiting for initial command, and not paused.
// Do servoing calculations only if the robot should move, for efficiency
// Create new outgoing joint trajectory command message
auto joint_trajectory = moveit::util::make_shared_from_pool<trajectory_msgs::JointTrajectory>();
// Prioritize cartesian servoing above joint servoing
// Only run commands if not stale and nonzero
if (have_nonzero_twist_stamped_ && !twist_command_is_stale_)
{
if (!cartesianServoCalcs(twist_stamped_cmd_, *joint_trajectory))
{
resetLowPassFilters(original_joint_state_);
return;
}
}
else if (have_nonzero_joint_command_ && !joint_command_is_stale_)
{
if (!jointServoCalcs(joint_servo_cmd_, *joint_trajectory))
{
resetLowPassFilters(original_joint_state_);
return;
}
}
else
{
// Joint trajectory is not populated with anything, so set it to the last positions and 0 velocity
*joint_trajectory = *last_sent_command_;
for (auto& point : joint_trajectory->points)
{
point.velocities.assign(point.velocities.size(), 0);
}
}
// Print a warning to the user if both are stale
if (!twist_command_is_stale_ || !joint_command_is_stale_)
{
ROS_WARN_STREAM_THROTTLE_NAMED(10, LOGNAME,
"Stale command. "
"Try a larger 'incoming_command_timeout' parameter?");
}
// If we should halt
if (!have_nonzero_command_)
{
suddenHalt(*joint_trajectory);
have_nonzero_twist_stamped_ = false;
have_nonzero_joint_command_ = false;
}
// Skip the servoing publication if all inputs have been zero for several cycles in a row.
// num_outgoing_halt_msgs_to_publish == 0 signifies that we should keep republishing forever.
if (!have_nonzero_command_ && (parameters_.num_outgoing_halt_msgs_to_publish != 0) &&
(zero_velocity_count_ > parameters_.num_outgoing_halt_msgs_to_publish))
{
ok_to_publish_ = false;
ROS_DEBUG_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME, "All-zero command. Doing nothing.");
}
else
{
ok_to_publish_ = true;
}
// Store last zero-velocity message flag to prevent superfluous warnings.
// Cartesian and joint commands must both be zero.
if (!have_nonzero_command_)
{
// Avoid overflow
if (zero_velocity_count_ < std::numeric_limits<int>::max())
++zero_velocity_count_;
}
else
{
zero_velocity_count_ = 0;
}
if (ok_to_publish_ && !paused_)
{
// Put the outgoing msg in the right format
// (trajectory_msgs/JointTrajectory or std_msgs/Float64MultiArray).
if (parameters_.command_out_type == "trajectory_msgs/JointTrajectory")
{
// When a joint_trajectory_controller receives a new command, a stamp of 0 indicates "begin immediately"
// See http://wiki.ros.org/joint_trajectory_controller#Trajectory_replacement
joint_trajectory->header.stamp = ros::Time(0);
outgoing_cmd_pub_.publish(joint_trajectory);
}
else if (parameters_.command_out_type == "std_msgs/Float64MultiArray")
{
auto joints = moveit::util::make_shared_from_pool<std_msgs::Float64MultiArray>();
if (parameters_.publish_joint_positions && !joint_trajectory->points.empty())
joints->data = joint_trajectory->points[0].positions;
else if (parameters_.publish_joint_velocities && !joint_trajectory->points.empty())
joints->data = joint_trajectory->points[0].velocities;
outgoing_cmd_pub_.publish(joints);
}
last_sent_command_ = joint_trajectory;
}
// Update the filters if we haven't yet
if (!updated_filters_)
resetLowPassFilters(original_joint_state_);
}
// Perform the servoing calculations
bool ServoCalcs::cartesianServoCalcs(geometry_msgs::TwistStamped& cmd,
trajectory_msgs::JointTrajectory& joint_trajectory)
{
// Check for nan's in the incoming command
if (std::isnan(cmd.twist.linear.x) || std::isnan(cmd.twist.linear.y) || std::isnan(cmd.twist.linear.z) ||
std::isnan(cmd.twist.angular.x) || std::isnan(cmd.twist.angular.y) || std::isnan(cmd.twist.angular.z))
{
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME,
"nan in incoming command. Skipping this datapoint.");
return false;
}
// If incoming commands should be in the range [-1:1], check for |delta|>1
if (parameters_.command_in_type == "unitless")
{
if ((fabs(cmd.twist.linear.x) > 1) || (fabs(cmd.twist.linear.y) > 1) || (fabs(cmd.twist.linear.z) > 1) ||
(fabs(cmd.twist.angular.x) > 1) || (fabs(cmd.twist.angular.y) > 1) || (fabs(cmd.twist.angular.z) > 1))
{
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME,
"Component of incoming command is >1. Skipping this datapoint.");
return false;
}
}
// Set uncontrolled dimensions to 0 in command frame
if (!control_dimensions_[0])
cmd.twist.linear.x = 0;
if (!control_dimensions_[1])
cmd.twist.linear.y = 0;
if (!control_dimensions_[2])
cmd.twist.linear.z = 0;
if (!control_dimensions_[3])
cmd.twist.angular.x = 0;
if (!control_dimensions_[4])
cmd.twist.angular.y = 0;
if (!control_dimensions_[5])
cmd.twist.angular.z = 0;
// Transform the command to the MoveGroup planning frame
if (cmd.header.frame_id != parameters_.planning_frame)
{
Eigen::Vector3d translation_vector(cmd.twist.linear.x, cmd.twist.linear.y, cmd.twist.linear.z);
Eigen::Vector3d angular_vector(cmd.twist.angular.x, cmd.twist.angular.y, cmd.twist.angular.z);
// If the incoming frame is empty or is the command frame, we use the previously calculated tf
if (cmd.header.frame_id.empty() || cmd.header.frame_id == parameters_.robot_link_command_frame)
{
translation_vector = tf_moveit_to_robot_cmd_frame_.linear() * translation_vector;
angular_vector = tf_moveit_to_robot_cmd_frame_.linear() * angular_vector;
}
else if (cmd.header.frame_id == parameters_.ee_frame_name)
{
// If the frame is the EE frame, we already have that transform as well
translation_vector = tf_moveit_to_ee_frame_.linear() * translation_vector;
angular_vector = tf_moveit_to_ee_frame_.linear() * angular_vector;
}
else
{
// We solve (planning_frame -> base -> cmd.header.frame_id)
// by computing (base->planning_frame)^-1 * (base->cmd.header.frame_id)
const auto tf_moveit_to_incoming_cmd_frame =
current_state_->getGlobalLinkTransform(parameters_.planning_frame).inverse() *
current_state_->getGlobalLinkTransform(cmd.header.frame_id);
translation_vector = tf_moveit_to_incoming_cmd_frame.linear() * translation_vector;
angular_vector = tf_moveit_to_incoming_cmd_frame.linear() * angular_vector;
}
// Put these components back into a TwistStamped
cmd.header.frame_id = parameters_.planning_frame;
cmd.twist.linear.x = translation_vector(0);
cmd.twist.linear.y = translation_vector(1);
cmd.twist.linear.z = translation_vector(2);
cmd.twist.angular.x = angular_vector(0);
cmd.twist.angular.y = angular_vector(1);
cmd.twist.angular.z = angular_vector(2);
}
Eigen::VectorXd delta_x = scaleCartesianCommand(cmd);
// Convert from cartesian commands to joint commands
Eigen::MatrixXd jacobian = current_state_->getJacobian(joint_model_group_);
// May allow some dimensions to drift, based on drift_dimensions
// i.e. take advantage of task redundancy.
// Remove the Jacobian rows corresponding to True in the vector drift_dimensions
// Work backwards through the 6-vector so indices don't get out of order
for (auto dimension = jacobian.rows() - 1; dimension >= 0; --dimension)
{
if (drift_dimensions_[dimension] && jacobian.rows() > 1)
{
removeDimension(jacobian, delta_x, dimension);
}
}
Eigen::JacobiSVD<Eigen::MatrixXd> svd =
Eigen::JacobiSVD<Eigen::MatrixXd>(jacobian, Eigen::ComputeThinU | Eigen::ComputeThinV);
Eigen::MatrixXd matrix_s = svd.singularValues().asDiagonal();
Eigen::MatrixXd pseudo_inverse = svd.matrixV() * matrix_s.inverse() * svd.matrixU().transpose();
delta_theta_ = pseudo_inverse * delta_x;
enforceVelLimits(delta_theta_);
// If close to a collision or a singularity, decelerate
applyVelocityScaling(delta_theta_, velocityScalingFactorForSingularity(delta_x, svd, pseudo_inverse));
prev_joint_velocity_ = delta_theta_ / parameters_.publish_period;
return convertDeltasToOutgoingCmd(joint_trajectory);
}
bool ServoCalcs::jointServoCalcs(const control_msgs::JointJog& cmd, trajectory_msgs::JointTrajectory& joint_trajectory)
{
// Check for nan's
for (double velocity : cmd.velocities)
{
if (std::isnan(velocity))
{
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME,
"nan in incoming command. Skipping this datapoint.");
return false;
}
}
// Apply user-defined scaling
delta_theta_ = scaleJointCommand(cmd);
enforceVelLimits(delta_theta_);
// If close to a collision, decelerate
applyVelocityScaling(delta_theta_, 1.0 /* scaling for singularities -- ignore for joint motions */);
prev_joint_velocity_ = delta_theta_ / parameters_.publish_period;
return convertDeltasToOutgoingCmd(joint_trajectory);
}
bool ServoCalcs::convertDeltasToOutgoingCmd(trajectory_msgs::JointTrajectory& joint_trajectory)
{
internal_joint_state_ = original_joint_state_;
if (!addJointIncrements(internal_joint_state_, delta_theta_))
return false;
lowPassFilterPositions(internal_joint_state_);
// Calculate joint velocities here so that positions are filtered and SRDF bounds still get checked
calculateJointVelocities(internal_joint_state_, delta_theta_);
composeJointTrajMessage(internal_joint_state_, joint_trajectory);
if (!enforcePositionLimits())
{
suddenHalt(joint_trajectory);
status_ = StatusCode::JOINT_BOUND;
}
// done with calculations
if (parameters_.use_gazebo)
{
insertRedundantPointsIntoTrajectory(joint_trajectory, gazebo_redundant_message_count_);
}
return true;
}
// Spam several redundant points into the trajectory. The first few may be skipped if the
// time stamp is in the past when it reaches the client. Needed for gazebo simulation.
// Start from 2 because the first point's timestamp is already 1*parameters_.publish_period
void ServoCalcs::insertRedundantPointsIntoTrajectory(trajectory_msgs::JointTrajectory& joint_trajectory, int count) const
{
joint_trajectory.points.resize(count);
auto point = joint_trajectory.points[0];
// Start from 2 because we already have the first point. End at count+1 so (total #) == count
for (int i = 2; i < count; ++i)
{
point.time_from_start = ros::Duration(i * parameters_.publish_period);
joint_trajectory.points[i] = point;
}
}
void ServoCalcs::lowPassFilterPositions(sensor_msgs::JointState& joint_state)
{
for (size_t i = 0; i < position_filters_.size(); ++i)
{
joint_state.position[i] = position_filters_[i].filter(joint_state.position[i]);
}
updated_filters_ = true;
}
void ServoCalcs::resetLowPassFilters(const sensor_msgs::JointState& joint_state)
{
for (std::size_t i = 0; i < position_filters_.size(); ++i)
{
position_filters_[i].reset(joint_state.position[i]);
}
updated_filters_ = true;
}
void ServoCalcs::calculateJointVelocities(sensor_msgs::JointState& joint_state, const Eigen::ArrayXd& delta_theta)
{
for (int i = 0; i < delta_theta.size(); ++i)
{
joint_state.velocity[i] = delta_theta[i] / parameters_.publish_period;
}
}
void ServoCalcs::composeJointTrajMessage(const sensor_msgs::JointState& joint_state,
trajectory_msgs::JointTrajectory& joint_trajectory) const
{
// When a joint_trajectory_controller receives a new command, a stamp of 0 indicates "begin immediately"
// See http://wiki.ros.org/joint_trajectory_controller#Trajectory_replacement
joint_trajectory.header.stamp = ros::Time(0);
joint_trajectory.header.frame_id = parameters_.planning_frame;
joint_trajectory.joint_names = joint_state.name;
trajectory_msgs::JointTrajectoryPoint point;
point.time_from_start = ros::Duration(parameters_.publish_period);
if (parameters_.publish_joint_positions)
point.positions = joint_state.position;
if (parameters_.publish_joint_velocities)
point.velocities = joint_state.velocity;
if (parameters_.publish_joint_accelerations)
{
// I do not know of a robot that takes acceleration commands.
// However, some controllers check that this data is non-empty.
// Send all zeros, for now.
std::vector<double> acceleration(num_joints_);
point.accelerations = acceleration;
}
joint_trajectory.points.push_back(point);
}
// Apply velocity scaling for proximity of collisions and singularities.
void ServoCalcs::applyVelocityScaling(Eigen::ArrayXd& delta_theta, double singularity_scale)
{
double collision_scale = collision_velocity_scale_;
if (collision_scale > 0 && collision_scale < 1)
{
status_ = StatusCode::DECELERATE_FOR_COLLISION;
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME, SERVO_STATUS_CODE_MAP.at(status_));
}
else if (collision_scale == 0)
{
status_ = StatusCode::HALT_FOR_COLLISION;
}
delta_theta = collision_scale * singularity_scale * delta_theta;
if (status_ == StatusCode::HALT_FOR_COLLISION)
{
ROS_WARN_STREAM_THROTTLE_NAMED(3, LOGNAME, "Halting for collision!");
delta_theta_.setZero();
}
}
// Possibly calculate a velocity scaling factor, due to proximity of singularity and direction of motion
double ServoCalcs::velocityScalingFactorForSingularity(const Eigen::VectorXd& commanded_velocity,
const Eigen::JacobiSVD<Eigen::MatrixXd>& svd,
const Eigen::MatrixXd& pseudo_inverse)
{
double velocity_scale = 1;
std::size_t num_dimensions = commanded_velocity.size();
// Find the direction away from nearest singularity.
// The last column of U from the SVD of the Jacobian points directly toward or away from the singularity.
// The sign can flip at any time, so we have to do some extra checking.
// Look ahead to see if the Jacobian's condition will decrease.
Eigen::VectorXd vector_toward_singularity = svd.matrixU().col(num_dimensions - 1);
double ini_condition = svd.singularValues()(0) / svd.singularValues()(svd.singularValues().size() - 1);
// This singular vector tends to flip direction unpredictably. See R. Bro,
// "Resolving the Sign Ambiguity in the Singular Value Decomposition".
// Look ahead to see if the Jacobian's condition will decrease in this
// direction. Start with a scaled version of the singular vector
Eigen::VectorXd delta_x(num_dimensions);
double scale = 100;
delta_x = vector_toward_singularity / scale;
// Calculate a small change in joints
Eigen::VectorXd new_theta;
current_state_->copyJointGroupPositions(joint_model_group_, new_theta);
new_theta += pseudo_inverse * delta_x;
current_state_->setJointGroupPositions(joint_model_group_, new_theta);
Eigen::MatrixXd new_jacobian = current_state_->getJacobian(joint_model_group_);
Eigen::JacobiSVD<Eigen::MatrixXd> new_svd(new_jacobian);
double new_condition = new_svd.singularValues()(0) / new_svd.singularValues()(new_svd.singularValues().size() - 1);
// If new_condition < ini_condition, the singular vector does point towards a
// singularity. Otherwise, flip its direction.
if (ini_condition >= new_condition)
{
vector_toward_singularity *= -1;
}
// If this dot product is positive, we're moving toward singularity ==> decelerate
double dot = vector_toward_singularity.dot(commanded_velocity);
if (dot > 0)
{
// Ramp velocity down linearly when the Jacobian condition is between lower_singularity_threshold and
// hard_stop_singularity_threshold, and we're moving towards the singularity
if ((ini_condition > parameters_.lower_singularity_threshold) &&
(ini_condition < parameters_.hard_stop_singularity_threshold))
{
velocity_scale = 1. - (ini_condition - parameters_.lower_singularity_threshold) /
(parameters_.hard_stop_singularity_threshold - parameters_.lower_singularity_threshold);
status_ = StatusCode::DECELERATE_FOR_SINGULARITY;
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME, SERVO_STATUS_CODE_MAP.at(status_));
}
// Very close to singularity, so halt.
else if (ini_condition > parameters_.hard_stop_singularity_threshold)
{
velocity_scale = 0;
status_ = StatusCode::HALT_FOR_SINGULARITY;
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME, SERVO_STATUS_CODE_MAP.at(status_));
}
}
return velocity_scale;
}
void ServoCalcs::enforceVelLimits(Eigen::ArrayXd& delta_theta)
{
// Convert to joint angle velocities for checking and applying joint specific velocity limits.
Eigen::ArrayXd velocity = delta_theta / parameters_.publish_period;
std::size_t joint_delta_index{ 0 };
double velocity_scaling_factor{ 1.0 };
for (const moveit::core::JointModel* joint : joint_model_group_->getActiveJointModels())
{
const auto& bounds = joint->getVariableBounds(joint->getName());
if (bounds.velocity_bounded_ && velocity(joint_delta_index) != 0.0)
{
const double unbounded_velocity = velocity(joint_delta_index);
// Clamp each joint velocity to a joint specific [min_velocity, max_velocity] range.
const auto bounded_velocity = std::min(std::max(unbounded_velocity, bounds.min_velocity_), bounds.max_velocity_);
velocity_scaling_factor = std::min(velocity_scaling_factor, bounded_velocity / unbounded_velocity);
}
++joint_delta_index;
}
// Convert back to joint angle increments.
delta_theta = velocity_scaling_factor * velocity * parameters_.publish_period;
}
bool ServoCalcs::enforcePositionLimits()
{
bool halting = false;
for (auto joint : joint_model_group_->getActiveJointModels())
{
// Halt if we're past a joint margin and joint velocity is moving even farther past
double joint_angle = 0;
for (std::size_t c = 0; c < original_joint_state_.name.size(); ++c)
{
if (original_joint_state_.name[c] == joint->getName())
{
joint_angle = original_joint_state_.position.at(c);
break;
}
}
if (!current_state_->satisfiesPositionBounds(joint, -parameters_.joint_limit_margin))
{
const std::vector<moveit_msgs::JointLimits> limits = joint->getVariableBoundsMsg();
// Joint limits are not defined for some joints. Skip them.
if (!limits.empty())
{
if ((current_state_->getJointVelocities(joint)[0] < 0 &&
(joint_angle < (limits[0].min_position + parameters_.joint_limit_margin))) ||
(current_state_->getJointVelocities(joint)[0] > 0 &&
(joint_angle > (limits[0].max_position - parameters_.joint_limit_margin))))
{
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME,
ros::this_node::getName() << " " << joint->getName()
<< " close to a "
" position limit. Halting.");
halting = true;
}
}
}
}
return !halting;
}
// Suddenly halt for a joint limit or other critical issue.
// Is handled differently for position vs. velocity control.
void ServoCalcs::suddenHalt(trajectory_msgs::JointTrajectory& joint_trajectory)
{
// Prepare the joint trajectory message to stop the robot
joint_trajectory.points.clear();
joint_trajectory.points.emplace_back();
trajectory_msgs::JointTrajectoryPoint& point = joint_trajectory.points.front();
// When sending out trajectory_msgs/JointTrajectory type messages, the "trajectory" is just a single point.
// That point cannot have the same timestamp as the start of trajectory execution since that would mean the
// arm has to reach the first trajectory point the moment execution begins. To prevent errors about points
// being 0 seconds in the past, the smallest supported timestep is added as time from start to the trajectory point.
point.time_from_start.fromNSec(1);
point.positions.resize(num_joints_);
point.velocities.resize(num_joints_);
// Assert the following loop is safe to execute
assert(original_joint_state_.position.size() >= num_joints_);
// Set the positions and velocities vectors
for (std::size_t i = 0; i < num_joints_; ++i)
{
// For position-controlled robots, can reset the joints to a known, good state
if (parameters_.publish_joint_positions)
point.positions[i] = original_joint_state_.position[i];
// For velocity-controlled robots, stop
if (parameters_.publish_joint_velocities)
point.velocities[i] = 0;
}
}
// Parse the incoming joint msg for the joints of our MoveGroup
void ServoCalcs::updateJoints()
{
// Get the latest joint group positions
current_state_ = planning_scene_monitor_->getStateMonitor()->getCurrentState();
current_state_->copyJointGroupPositions(joint_model_group_, internal_joint_state_.position);
current_state_->copyJointGroupVelocities(joint_model_group_, internal_joint_state_.velocity);
// Cache the original joints in case they need to be reset
original_joint_state_ = internal_joint_state_;
// Calculate worst case joint stop time, for collision checking
std::string joint_name = "";
moveit::core::JointModel::Bounds kinematic_bounds;
double accel_limit = 0;
double joint_velocity = 0;
double worst_case_stop_time = 0;
for (size_t jt_state_idx = 0; jt_state_idx < internal_joint_state_.velocity.size(); ++jt_state_idx)
{
joint_name = internal_joint_state_.name[jt_state_idx];
// Get acceleration limit for this joint
for (auto joint_model : joint_model_group_->getActiveJointModels())
{
if (joint_model->getName() == joint_name)
{
kinematic_bounds = joint_model->getVariableBounds();
// Some joints do not have acceleration limits
if (kinematic_bounds[0].acceleration_bounded_)
{
// Be conservative when calculating overall acceleration limit from min and max limits
accel_limit =
std::min(fabs(kinematic_bounds[0].min_acceleration_), fabs(kinematic_bounds[0].max_acceleration_));
}
else
{
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME,
"An acceleration limit is not defined for this joint; minimum stop distance "
"should not be used for collision checking");
}
break;
}
}
// Get the current joint velocity
joint_velocity = internal_joint_state_.velocity[jt_state_idx];
// Calculate worst case stop time
worst_case_stop_time = std::max(worst_case_stop_time, fabs(joint_velocity / accel_limit));
}
// publish message
{
auto msg = moveit::util::make_shared_from_pool<std_msgs::Float64>();
msg->data = worst_case_stop_time;
worst_case_stop_time_pub_.publish(msg);
}
}
// Scale the incoming servo command
Eigen::VectorXd ServoCalcs::scaleCartesianCommand(const geometry_msgs::TwistStamped& command) const
{
Eigen::VectorXd result(6);
// Apply user-defined scaling if inputs are unitless [-1:1]
if (parameters_.command_in_type == "unitless")
{
result[0] = parameters_.linear_scale * parameters_.publish_period * command.twist.linear.x;
result[1] = parameters_.linear_scale * parameters_.publish_period * command.twist.linear.y;
result[2] = parameters_.linear_scale * parameters_.publish_period * command.twist.linear.z;
result[3] = parameters_.rotational_scale * parameters_.publish_period * command.twist.angular.x;
result[4] = parameters_.rotational_scale * parameters_.publish_period * command.twist.angular.y;
result[5] = parameters_.rotational_scale * parameters_.publish_period * command.twist.angular.z;
}
// Otherwise, commands are in m/s and rad/s
else if (parameters_.command_in_type == "speed_units")
{
result[0] = command.twist.linear.x * parameters_.publish_period;
result[1] = command.twist.linear.y * parameters_.publish_period;
result[2] = command.twist.linear.z * parameters_.publish_period;
result[3] = command.twist.angular.x * parameters_.publish_period;
result[4] = command.twist.angular.y * parameters_.publish_period;
result[5] = command.twist.angular.z * parameters_.publish_period;
}
else
ROS_ERROR_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME, "Unexpected command_in_type");
return result;
}
Eigen::VectorXd ServoCalcs::scaleJointCommand(const control_msgs::JointJog& command) const
{
Eigen::VectorXd result(num_joints_);
result.setZero();
std::size_t c;
for (std::size_t m = 0; m < command.joint_names.size(); ++m)
{
try
{
c = joint_state_name_map_.at(command.joint_names[m]);
}
catch (const std::out_of_range& e)
{
ROS_WARN_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME, "Ignoring joint " << command.joint_names[m]);
continue;
}
// Apply user-defined scaling if inputs are unitless [-1:1]
if (parameters_.command_in_type == "unitless")
result[c] = command.velocities[m] * parameters_.joint_scale * parameters_.publish_period;
// Otherwise, commands are in m/s and rad/s
else if (parameters_.command_in_type == "speed_units")
result[c] = command.velocities[m] * parameters_.publish_period;
else
ROS_ERROR_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME, "Unexpected command_in_type, check yaml file.");
}
return result;
}
// Add the deltas to each joint
bool ServoCalcs::addJointIncrements(sensor_msgs::JointState& output, const Eigen::VectorXd& increments) const
{
for (std::size_t i = 0, size = static_cast<std::size_t>(increments.size()); i < size; ++i)
{
try
{
output.position[i] += increments[i];
}
catch (const std::out_of_range& e)
{
ROS_ERROR_STREAM_THROTTLE_NAMED(ROS_LOG_THROTTLE_PERIOD, LOGNAME,
ros::this_node::getName() << " Lengths of output and "
"increments do not match.");
return false;
}
}
return true;
}
void ServoCalcs::removeDimension(Eigen::MatrixXd& jacobian, Eigen::VectorXd& delta_x, unsigned int row_to_remove)
{
unsigned int num_rows = jacobian.rows() - 1;