joint_position_controller.cpp
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00034 
00035 #include "robot_mechanism_controllers/joint_position_controller.h"
00036 #include "angles/angles.h"
00037 #include "pluginlib/class_list_macros.h"
00038 
00039 PLUGINLIB_EXPORT_CLASS( controller::JointPositionController, pr2_controller_interface::Controller)
00040 
00041 using namespace std;
00042 
00043 namespace controller {
00044 
00045 JointPositionController::JointPositionController()
00046 : joint_state_(NULL), command_(0),
00047   loop_count_(0),  initialized_(false), robot_(NULL), last_time_(0)
00048 {
00049 }
00050 
00051 JointPositionController::~JointPositionController()
00052 {
00053   sub_command_.shutdown();
00054 }
00055 
00056 bool JointPositionController::init(pr2_mechanism_model::RobotState *robot, const std::string &joint_name,
00057                                    const control_toolbox::Pid &pid)
00058 {
00059   assert(robot);
00060   robot_ = robot;
00061   last_time_ = robot->getTime();
00062 
00063   joint_state_ = robot_->getJointState(joint_name);
00064   if (!joint_state_)
00065   {
00066     ROS_ERROR("JointPositionController could not find joint named \"%s\"\n",
00067               joint_name.c_str());
00068     return false;
00069   }
00070   if (!joint_state_->calibrated_)
00071   {
00072     ROS_ERROR("Joint %s not calibrated for JointPositionController", joint_name.c_str());
00073     return false;
00074   }
00075 
00076   pid_controller_ = pid;
00077 
00078   return true;
00079 }
00080 
00081 bool JointPositionController::init(pr2_mechanism_model::RobotState *robot, ros::NodeHandle &n)
00082 {
00083   assert(robot);
00084   node_ = n;
00085 
00086   std::string joint_name;
00087   if (!node_.getParam("joint", joint_name)) {
00088     ROS_ERROR("No joint given (namespace: %s)", node_.getNamespace().c_str());
00089     return false;
00090   }
00091 
00092   control_toolbox::Pid pid;
00093   if (!pid.init(ros::NodeHandle(node_, "pid")))
00094     return false;
00095 
00096   controller_state_publisher_.reset(
00097     new realtime_tools::RealtimePublisher<pr2_controllers_msgs::JointControllerState>
00098     (node_, "state", 1));
00099 
00100   sub_command_ = node_.subscribe<std_msgs::Float64>("command", 1, &JointPositionController::setCommandCB, this);
00101 
00102   return init(robot, joint_name, pid);
00103 }
00104 
00105 
00106 void JointPositionController::setGains(const double &p, const double &i, const double &d, const double &i_max, const double &i_min)
00107 {
00108   pid_controller_.setGains(p,i,d,i_max,i_min);
00109 }
00110 
00111 void JointPositionController::getGains(double &p, double &i, double &d, double &i_max, double &i_min)
00112 {
00113   pid_controller_.getGains(p,i,d,i_max,i_min);
00114 }
00115 
00116 std::string JointPositionController::getJointName()
00117 {
00118   return joint_state_->joint_->name;
00119 }
00120 
00121 // Set the joint position command
00122 void JointPositionController::setCommand(double cmd)
00123 {
00124   command_ = cmd;
00125 }
00126 
00127 // Return the current position command
00128 void JointPositionController::getCommand(double & cmd)
00129 {
00130   cmd = command_;
00131 }
00132 
00133 void JointPositionController::update()
00134 {
00135   if (!joint_state_->calibrated_)
00136     return;
00137 
00138   assert(robot_ != NULL);
00139   double error(0);
00140   ros::Time time = robot_->getTime();
00141   assert(joint_state_->joint_);
00142   dt_= time - last_time_;
00143 
00144   if (!initialized_)
00145   {
00146     initialized_ = true;
00147     command_ = joint_state_->position_;
00148   }
00149 
00150   if(joint_state_->joint_->type == urdf::Joint::REVOLUTE)
00151   {
00152     angles::shortest_angular_distance_with_limits(
00153           joint_state_->position_,
00154           command_,
00155           joint_state_->joint_->limits->lower,
00156           joint_state_->joint_->limits->upper,
00157           error);
00158 
00159   }
00160   else if(joint_state_->joint_->type == urdf::Joint::CONTINUOUS)
00161   {
00162     error = angles::shortest_angular_distance(joint_state_->position_,
00163           command_);
00164   }
00165   else //prismatic
00166   {
00167     error = command_ - joint_state_->position_;
00168   }
00169 
00170   double commanded_effort = pid_controller_.computeCommand(error, 
00171         0.0 - joint_state_->velocity_, dt_); // assuming desired velocity is 0
00172   joint_state_->commanded_effort_ = commanded_effort;
00173 
00174   if(loop_count_ % 10 == 0)
00175   {
00176     if(controller_state_publisher_ && controller_state_publisher_->trylock())
00177     {
00178       controller_state_publisher_->msg_.header.stamp = time;
00179       controller_state_publisher_->msg_.set_point = command_;
00180       controller_state_publisher_->msg_.process_value = joint_state_->position_;
00181       controller_state_publisher_->msg_.process_value_dot = joint_state_->velocity_;
00182       controller_state_publisher_->msg_.error = error;
00183       controller_state_publisher_->msg_.time_step = dt_.toSec();
00184       controller_state_publisher_->msg_.command = commanded_effort;
00185 
00186       double dummy;
00187       getGains(controller_state_publisher_->msg_.p,
00188                controller_state_publisher_->msg_.i,
00189                controller_state_publisher_->msg_.d,
00190                controller_state_publisher_->msg_.i_clamp,
00191                dummy);
00192       controller_state_publisher_->unlockAndPublish();
00193     }
00194   }
00195   loop_count_++;
00196 
00197   last_time_ = time;
00198 }
00199 
00200 void JointPositionController::setCommandCB(const std_msgs::Float64ConstPtr& msg)
00201 {
00202   command_ = msg->data;
00203 }
00204 
00205 }


robot_mechanism_controllers
Author(s): John Hsu, Melonee Wise, Stuart Glaser
autogenerated on Thu Aug 27 2015 14:22:45