pr2_base_controller.cpp

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/*
 * Author: Sachin Chitta and Matthew Piccoli
 */
 
#include "pr2_mechanism_controllers/pr2_base_controller.h"
#include "pluginlib/class_list_macros.hpp"
 
PLUGINLIB_EXPORT_CLASS( controller::Pr2BaseController, pr2_controller_interface::Controller)
 
namespace controller {
 
  const static double EPS = 1e-5;
 
Pr2BaseController::Pr2BaseController()
{
  //init variables
  cmd_vel_.linear.x = 0;
  cmd_vel_.linear.y = 0;
  cmd_vel_.angular.z = 0;
 
  desired_vel_.linear.x = 0;
  desired_vel_.linear.y = 0;
  desired_vel_.angular.z = 0;
 
  cmd_vel_t_.linear.x = 0;
  cmd_vel_t_.linear.y = 0;
  cmd_vel_t_.angular.z = 0;
 
  new_cmd_available_ = false;
  last_publish_time_ = ros::Time(0.0);
 
  pthread_mutex_init(&pr2_base_controller_lock_, NULL);
}
 
Pr2BaseController::~Pr2BaseController()
{
  cmd_sub_.shutdown();
  cmd_sub_deprecated_.shutdown();
}
 
bool Pr2BaseController::init(pr2_mechanism_model::RobotState *robot, ros::NodeHandle &n)
{
  if(!base_kin_.init(robot,n))
    return false;
  node_ = n;
  state_publisher_.reset(new realtime_tools::RealtimePublisher<pr2_mechanism_controllers::BaseControllerState>(n, base_kin_.name_ + "/state", 1));
 
  int num_joints = base_kin_.num_wheels_ + base_kin_.num_casters_;
  state_publisher_->msg_.joint_names.resize(num_joints);
  state_publisher_->msg_.joint_velocity_measured.resize(num_joints);
  state_publisher_->msg_.joint_effort_measured.resize(num_joints);
  state_publisher_->msg_.joint_velocity_commanded.resize(num_joints);
  state_publisher_->msg_.joint_effort_commanded.resize(num_joints);
  state_publisher_->msg_.joint_velocity_error.resize(num_joints);
  state_publisher_->msg_.joint_effort_error.resize(num_joints);
 
  //Get params from param server
  node_.param<double> ("max_translational_velocity", max_translational_velocity_,0.5);
  node_.param<double> ("max_rotational_velocity", max_rotational_velocity_, 10.0); //0.5
  node_.param<double> ("max_translational_acceleration/x", max_accel_.linear.x, .2);
  node_.param<double> ("max_translational_acceleration/y", max_accel_.linear.y, .2);
  node_.param<double> ("max_rotational_acceleration", max_accel_.angular.z, 10.0); //0.2
 
  node_.param<double> ("kp_caster_steer", kp_caster_steer_, 80.0);
  node_.param<double> ("timeout", timeout_, 1.0);
  node_.param<double> ("state_publish_rate", state_publish_rate_,2.0);
  if(state_publish_rate_ <= 0.0)
  {
    publish_state_ = false;
    state_publish_time_ = 0.0;
  }
  else
  {
    publish_state_ = true;
    state_publish_time_ = 1.0/state_publish_rate_;
  }
 
  //  cmd_sub_deprecated_ = root_handle_.subscribe<geometry_msgs::Twist>("cmd_vel", 1, &Pr2BaseController::commandCallback, this);
  cmd_sub_ = node_.subscribe<geometry_msgs::Twist>("command", 1, &Pr2BaseController::commandCallback, this);
 
  //casters
  caster_controller_.resize(base_kin_.num_casters_);
  caster_position_pid_.resize(base_kin_.num_casters_);
  for(int i = 0; i < base_kin_.num_casters_; i++)
  {
    control_toolbox::Pid p_i_d;
    state_publisher_->msg_.joint_names[i] = base_kin_.caster_[i].joint_name_;
    if(!p_i_d.init(ros::NodeHandle(node_, base_kin_.caster_[i].joint_name_+"/velocity_controller")))
    {
      ROS_ERROR("Could not initialize pid for %s",base_kin_.caster_[i].joint_name_.c_str());
      return false;
    }
 
    if(!caster_position_pid_[i].init(ros::NodeHandle(node_, base_kin_.caster_[i].joint_name_+"/position_controller")))
    {
      ROS_ERROR("Could not initialize position pid controller for %s",base_kin_.caster_[i].joint_name_.c_str());
      return false;
    }
    caster_controller_[i].reset(new JointVelocityController());
    if(!caster_controller_[i]->init(base_kin_.robot_state_, base_kin_.caster_[i].joint_name_, p_i_d))
    {
      ROS_ERROR("Could not initialize pid for %s",base_kin_.caster_[i].joint_name_.c_str());
      return false;
    }
    if (!caster_controller_[i]->joint_state_->calibrated_)
    {
      ROS_ERROR("Caster joint \"%s\" not calibrated (namespace: %s)",
                base_kin_.caster_[i].joint_name_.c_str(), node_.getNamespace().c_str());
      return false;
    }
  }
  //wheels
  wheel_controller_.resize(base_kin_.num_wheels_);
  for(int j = 0; j < base_kin_.num_wheels_; j++)
  {
    control_toolbox::Pid p_i_d;
    state_publisher_->msg_.joint_names[j + base_kin_.num_casters_] = base_kin_.wheel_[j].joint_name_;
    if(!p_i_d.init(ros::NodeHandle(node_,base_kin_.wheel_[j].joint_name_)))
    {
      ROS_ERROR("Could not initialize pid for %s",base_kin_.wheel_[j].joint_name_.c_str());
      return false;
    }
    wheel_controller_[j].reset(new JointVelocityController());
   if(!wheel_controller_[j]->init(base_kin_.robot_state_, base_kin_.wheel_[j].joint_name_, p_i_d))
   {
      ROS_ERROR("Could not initialize joint velocity controller for %s",base_kin_.wheel_[j].joint_name_.c_str());
      return false;
   }
  }
  for(int i = 0; i < base_kin_.num_casters_; ++i)
  {
    if(!base_kin_.caster_[i].joint_->calibrated_)
    {
      ROS_ERROR("The Base controller could not start because the casters were not calibrated. Relaunch the base controller after you see the caster calibration finish.");
      return false; // Casters are not calibrated
    }
  }
 
  if (!((filters::MultiChannelFilterBase<double>&)caster_vel_filter_).configure(base_kin_.num_casters_, std::string("caster_velocity_filter"), node_)){
     ROS_ERROR("BaseController: could not configure velocity filters for casters");
     return false;
  }
  filtered_velocity_.resize(base_kin_.num_casters_);
  return true;
}
 
// Set the base velocity command
void Pr2BaseController::setCommand(const geometry_msgs::Twist &cmd_vel)
{
  double vel_mag = sqrt(cmd_vel.linear.x * cmd_vel.linear.x + cmd_vel.linear.y * cmd_vel.linear.y);
  double clamped_vel_mag = filters::clamp(vel_mag,-max_translational_velocity_, max_translational_velocity_);
  if(vel_mag > EPS)
  {
    cmd_vel_t_.linear.x = cmd_vel.linear.x * clamped_vel_mag / vel_mag;
    cmd_vel_t_.linear.y = cmd_vel.linear.y * clamped_vel_mag / vel_mag;
  }
  else
  {
    cmd_vel_t_.linear.x = 0.0;
    cmd_vel_t_.linear.y = 0.0;
  }
  cmd_vel_t_.angular.z = filters::clamp(cmd_vel.angular.z, -max_rotational_velocity_, max_rotational_velocity_);
  cmd_received_timestamp_ = base_kin_.robot_state_->getTime();
 
  ROS_DEBUG("BaseController:: command received: %f %f %f",cmd_vel.linear.x,cmd_vel.linear.y,cmd_vel.angular.z);
  ROS_DEBUG("BaseController:: command current: %f %f %f", cmd_vel_.linear.x,cmd_vel_.linear.y,cmd_vel_.angular.z);
  ROS_DEBUG("BaseController:: clamped vel: %f", clamped_vel_mag);
  ROS_DEBUG("BaseController:: vel: %f", vel_mag);
 
  for(int i=0; i < (int) base_kin_.num_wheels_; i++)
  {
    ROS_DEBUG("BaseController:: wheel speed cmd:: %d %f",i,(base_kin_.wheel_[i].direction_multiplier_*base_kin_.wheel_[i].wheel_speed_cmd_));
  }
  for(int i=0; i < (int) base_kin_.num_casters_; i++)
  {
    ROS_DEBUG("BaseController:: caster speed cmd:: %d %f",i,(base_kin_.caster_[i].steer_velocity_desired_));
  }
  new_cmd_available_ = true;
}
 
geometry_msgs::Twist Pr2BaseController::interpolateCommand(const geometry_msgs::Twist &start, const geometry_msgs::Twist &end, const geometry_msgs::Twist &max_rate, const double &dT)
{
  geometry_msgs::Twist result;
  geometry_msgs::Twist alpha;
  double delta(0), max_delta(0);
 
  delta = end.linear.x - start.linear.x;
  max_delta = max_rate.linear.x * dT;
  if(fabs(delta) <= max_delta || max_delta < EPS)
    alpha.linear.x = 1;
  else
    alpha.linear.x = max_delta / fabs(delta);
 
  delta = end.linear.y - start.linear.y;
  max_delta = max_rate.linear.y * dT;
  if(fabs(delta) <= max_delta || max_delta < EPS)
    alpha.linear.y = 1;
  else
    alpha.linear.y = max_delta / fabs(delta);
 
  delta = end.angular.z - start.angular.z;
  max_delta = max_rate.angular.z * dT;
  if(fabs(delta) <= max_delta || max_delta < EPS)
    alpha.angular.z = 1;
  else
    alpha.angular.z = max_delta / fabs(delta);
 
  double alpha_min = alpha.linear.x;
  if(alpha.linear.y < alpha_min)
    alpha_min = alpha.linear.y;
  if(alpha.angular.z < alpha_min)
    alpha_min = alpha.angular.z;
 
  result.linear.x = start.linear.x + alpha_min * (end.linear.x - start.linear.x);
  result.linear.y = start.linear.y + alpha_min * (end.linear.y - start.linear.y);
  result.angular.z = start.angular.z + alpha_min * (end.angular.z - start.angular.z);
  return result;
}
 
geometry_msgs::Twist Pr2BaseController::getCommand()// Return the current velocity command
{
  geometry_msgs::Twist cmd_vel;
  pthread_mutex_lock(&pr2_base_controller_lock_);
  cmd_vel.linear.x = cmd_vel_.linear.x;
  cmd_vel.linear.y = cmd_vel_.linear.y;
  cmd_vel.angular.z = cmd_vel_.angular.z;
  pthread_mutex_unlock(&pr2_base_controller_lock_);
  return cmd_vel;
}
 
void Pr2BaseController::starting()
{
  last_time_ = base_kin_.robot_state_->getTime();
  cmd_received_timestamp_ = base_kin_.robot_state_->getTime();
  for(int i = 0; i < base_kin_.num_casters_; i++)
  {
    caster_controller_[i]->starting();
  }
  for(int j = 0; j < base_kin_.num_wheels_; j++)
  {
    wheel_controller_[j]->starting();
  }
}
 
void Pr2BaseController::update()
{
  ros::Time current_time = base_kin_.robot_state_->getTime();
  double dT = std::min<double>((current_time - last_time_).toSec(), base_kin_.MAX_DT_);
 
  if(new_cmd_available_)
  {
    if(pthread_mutex_trylock(&pr2_base_controller_lock_) == 0)
    {
      desired_vel_.linear.x = cmd_vel_t_.linear.x;
      desired_vel_.linear.y = cmd_vel_t_.linear.y;
      desired_vel_.angular.z = cmd_vel_t_.angular.z;
      new_cmd_available_ = false;
      pthread_mutex_unlock(&pr2_base_controller_lock_);
    }
  }
 
  if((current_time - cmd_received_timestamp_).toSec() > timeout_)
  {
    cmd_vel_.linear.x = 0;
    cmd_vel_.linear.y = 0;
    cmd_vel_.angular.z = 0;
  }
  else
    cmd_vel_ = interpolateCommand(cmd_vel_, desired_vel_, max_accel_, dT);
 
  computeJointCommands(dT);
 
  setJointCommands();
 
  updateJointControllers();
 
  if(publish_state_)
    publishState(current_time);
 
  last_time_ = current_time;
 
}
 
void Pr2BaseController::publishState(const ros::Time &time)
{
  if((time - last_publish_time_).toSec()  < state_publish_time_)
  {
    return;
  }
 
  if(state_publisher_->trylock())
  {
    state_publisher_->msg_.command.linear.x  = cmd_vel_.linear.x;
    state_publisher_->msg_.command.linear.y  = cmd_vel_.linear.y;
    state_publisher_->msg_.command.angular.z = cmd_vel_.angular.z;
 
    for(int i = 0; i < base_kin_.num_casters_; i++)
    {
      state_publisher_->msg_.joint_names[i] = base_kin_.caster_[i].joint_name_;
      state_publisher_->msg_.joint_velocity_measured[i] = base_kin_.caster_[i].joint_->velocity_;
      state_publisher_->msg_.joint_velocity_commanded[i]= base_kin_.caster_[i].steer_velocity_desired_;
      state_publisher_->msg_.joint_velocity_error[i]    = base_kin_.caster_[i].joint_->velocity_ - base_kin_.caster_[i].steer_velocity_desired_;
 
      state_publisher_->msg_.joint_effort_measured[i]  = base_kin_.caster_[i].joint_->measured_effort_;
      state_publisher_->msg_.joint_effort_commanded[i] = base_kin_.caster_[i].joint_->commanded_effort_;
      state_publisher_->msg_.joint_effort_error[i]     = base_kin_.caster_[i].joint_->measured_effort_ - base_kin_.caster_[i].joint_->commanded_effort_;
    }
    for(int i = 0; i < base_kin_.num_wheels_; i++)
    {
      state_publisher_->msg_.joint_names[i+base_kin_.num_casters_] = base_kin_.wheel_[i].joint_name_;
      state_publisher_->msg_.joint_velocity_measured[i+base_kin_.num_casters_] = base_kin_.wheel_[i].wheel_speed_actual_;
      state_publisher_->msg_.joint_velocity_commanded[i+base_kin_.num_casters_]= base_kin_.wheel_[i].wheel_speed_error_;
      state_publisher_->msg_.joint_velocity_error[i+base_kin_.num_casters_]    = base_kin_.wheel_[i].wheel_speed_cmd_;
 
      state_publisher_->msg_.joint_effort_measured[i+base_kin_.num_casters_]  = base_kin_.wheel_[i].joint_->measured_effort_;
      state_publisher_->msg_.joint_effort_commanded[i+base_kin_.num_casters_] = base_kin_.wheel_[i].joint_->commanded_effort_;
      state_publisher_->msg_.joint_effort_error[i+base_kin_.num_casters_]     = base_kin_.wheel_[i].joint_->measured_effort_ - base_kin_.wheel_[i].joint_->commanded_effort_;
    }
    state_publisher_->unlockAndPublish();
    last_publish_time_ = time;
  }
}
 
void Pr2BaseController::computeJointCommands(const double &dT)
{
  base_kin_.computeWheelPositions();
 
  computeDesiredCasterSteer(dT);
 
  computeDesiredWheelSpeeds();
}
 
void Pr2BaseController::setJointCommands()
{
  setDesiredCasterSteer();
 
  setDesiredWheelSpeeds();
}
 
void Pr2BaseController::computeDesiredCasterSteer(const double &dT)
{
  geometry_msgs::Twist result;
 
  double steer_angle_desired(0.0), steer_angle_desired_m_pi(0.0);
  double error_steer(0.0), error_steer_m_pi(0.0);
  double trans_vel = sqrt(cmd_vel_.linear.x * cmd_vel_.linear.x + cmd_vel_.linear.y * cmd_vel_.linear.y);
 
  for(int i = 0; i < base_kin_.num_casters_; i++)
  {
    filtered_velocity_[i] = 0.0 - base_kin_.caster_[i].joint_->velocity_;
  }
  caster_vel_filter_.update(filtered_velocity_,filtered_velocity_);
 
  for(int i = 0; i < base_kin_.num_casters_; i++)
  {
    result = base_kin_.pointVel2D(base_kin_.caster_[i].offset_, cmd_vel_);
    if(trans_vel < EPS && fabs(cmd_vel_.angular.z) < EPS)
    {
      steer_angle_desired = base_kin_.caster_[i].steer_angle_stored_;
    }
    else
    {
      steer_angle_desired = atan2(result.linear.y, result.linear.x);
      base_kin_.caster_[i].steer_angle_stored_ = steer_angle_desired;
    }
    steer_angle_desired_m_pi = angles::normalize_angle(steer_angle_desired + M_PI);
    error_steer = angles::shortest_angular_distance(
          base_kin_.caster_[i].joint_->position_,
          steer_angle_desired);
    error_steer_m_pi = angles::shortest_angular_distance(
          base_kin_.caster_[i].joint_->position_,
          steer_angle_desired_m_pi);
 
    if(fabs(error_steer_m_pi) < fabs(error_steer))
    {
      error_steer = error_steer_m_pi;
      steer_angle_desired = steer_angle_desired_m_pi;
    }
    //    base_kin_.caster_[i].steer_velocity_desired_ = -kp_caster_steer_ * error_steer;
    base_kin_.caster_[i].steer_velocity_desired_ = caster_position_pid_[i].computeCommand(
          error_steer,
          filtered_velocity_[i],
          ros::Duration(dT));
    base_kin_.caster_[i].caster_position_error_ = error_steer;
  }
}
 
void Pr2BaseController::setDesiredCasterSteer()
{
  for(int i = 0; i < base_kin_.num_casters_; i++)
  {
    caster_controller_[i]->setCommand(base_kin_.caster_[i].steer_velocity_desired_);
  }
}
 
void Pr2BaseController::computeDesiredWheelSpeeds()
{
  geometry_msgs::Twist wheel_point_velocity;
  geometry_msgs::Twist wheel_point_velocity_projected;
  geometry_msgs::Twist wheel_caster_steer_component;
  geometry_msgs::Twist caster_2d_velocity;
 
  caster_2d_velocity.linear.x = 0;
  caster_2d_velocity.linear.y = 0;
  caster_2d_velocity.angular.z = 0;
 
  double steer_angle_actual = 0;
  for(int i = 0; i < (int) base_kin_.num_wheels_; i++)
  {
    base_kin_.wheel_[i].updatePosition();
    caster_2d_velocity.angular.z = base_kin_.wheel_[i].parent_->steer_velocity_desired_;
    steer_angle_actual = base_kin_.wheel_[i].parent_->joint_->position_;
    wheel_point_velocity = base_kin_.pointVel2D(base_kin_.wheel_[i].position_, cmd_vel_);
    wheel_caster_steer_component = base_kin_.pointVel2D(base_kin_.wheel_[i].offset_, caster_2d_velocity);
 
    double costh = cos(-steer_angle_actual);
    double sinth = sin(-steer_angle_actual);
 
    wheel_point_velocity_projected.linear.x = costh * wheel_point_velocity.linear.x - sinth * wheel_point_velocity.linear.y;
    wheel_point_velocity_projected.linear.y = sinth * wheel_point_velocity.linear.x + costh * wheel_point_velocity.linear.y;
    base_kin_.wheel_[i].wheel_speed_cmd_ = (wheel_point_velocity_projected.linear.x + wheel_caster_steer_component.linear.x) / (base_kin_.wheel_[i].wheel_radius_);
  }
}
 
void Pr2BaseController::setDesiredWheelSpeeds()
{
  for(int i = 0; i < (int) base_kin_.num_wheels_; i++)
  {
    wheel_controller_[i]->setCommand(base_kin_.wheel_[i].direction_multiplier_ * base_kin_.wheel_[i].wheel_speed_cmd_);
  }
}
 
void Pr2BaseController::updateJointControllers()
{
  for(int i = 0; i < base_kin_.num_wheels_; i++)
    wheel_controller_[i]->update();
  for(int i = 0; i < base_kin_.num_casters_; i++)
    caster_controller_[i]->update();
}
 
void Pr2BaseController::commandCallback(const geometry_msgs::TwistConstPtr& msg)
{
  pthread_mutex_lock(&pr2_base_controller_lock_);
  base_vel_msg_ = *msg;
  this->setCommand(base_vel_msg_);
  pthread_mutex_unlock(&pr2_base_controller_lock_);
}
} // namespace