allegroNode.cpp

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/*
 * allegroNode.cpp
 *
 *  Created on: Nov 14, 2012
 *  Authors: Alex ALSPACH, Seungsu KIM
 */
 
// CONTROL LOOP TEMPLATE 
// Using  timer callback  

// For the most basic torque control algorithm, 
// you need only add code where it says:
        // =============================== //
        // = COMPUTE control torque here = //
        // =============================== //   
// in the timer callback below. 
// READ, COMPUTE, and WRITE and PUBLISH
// are contrained within this callback.
 
#include <iostream>
#include <boost/thread/thread.hpp>
#include <boost/date_time.hpp>
#include <boost/thread/locks.hpp>

#include "ros/ros.h"
#include "ros/service.h"
#include "ros/service_server.h"
#include "sensor_msgs/JointState.h"
#include "std_msgs/String.h"

#include <stdio.h>
#include <iostream>
#include <string>

//#include "BHand/BHand.h"
#include "controlAllegroHand.h"

// Topics
#define JOINT_STATE_TOPIC "/allegroHand/joint_states"
#define JOINT_CMD_TOPIC "/allegroHand/joint_cmd"
#define EXT_CMD_TOPIC "/allegroHand/external_cmd"

#define JOINT_DESIRED_TOPIC "/allegroHand/joint_desired_states"
#define JOINT_CURRENT_TOPIC "/allegroHand/joint_current_states"


double desired_position[DOF_JOINTS]                             = {0.0};
double current_position[DOF_JOINTS]                     = {0.0};
double previous_position[DOF_JOINTS]                    = {0.0};
double current_position_filtered[DOF_JOINTS]    = {0.0};
double previous_position_filtered[DOF_JOINTS]   = {0.0};

double desired_velocity[DOF_JOINTS]                             = {0.0};
double current_velocity[DOF_JOINTS]                     = {0.0};
double previous_velocity[DOF_JOINTS]                    = {0.0};
double current_velocity_filtered[DOF_JOINTS]    = {0.0};

double desired_torque[DOF_JOINTS]                               = {0.0};


std::string jointNames[DOF_JOINTS]      = {    "joint_0.0",    "joint_1.0",    "joint_2.0",   "joint_3.0" , 
                                                                                   "joint_4.0",    "joint_5.0",    "joint_6.0",   "joint_7.0" , 
                                                                                   "joint_8.0",    "joint_9.0",    "joint_10.0",  "joint_11.0", 
                                                                                   "joint_12.0",   "joint_13.0",   "joint_14.0",  "joint_15.0" };

int frame = 0;

// Flags
int lEmergencyStop = 0;

boost::mutex *mutex;

// ROS Messages
ros::Publisher joint_state_pub;
ros::Publisher joint_desired_state_pub;
ros::Publisher joint_current_state_pub;

ros::Subscriber joint_cmd_sub;                          // Handles external joint command (eg. sensor_msgs/JointState)
ros::Subscriber external_cmd_sub;                       // Handles any other type of eternal command (eg. std_msgs/String)
sensor_msgs::JointState msgJoint_desired;       // Desired Position, Desired Velocity, Desired Torque
sensor_msgs::JointState msgJoint_current;       // Current Position, Current Velocity, NOTE: Current Torque Unavailable
sensor_msgs::JointState msgJoint;                       // Collects most relavent information in one message: Current Position, Current Velocity, Control Torque
std::string  ext_cmd;

// ROS Time
ros::Time tstart;
ros::Time tnow;
double secs;
double dt;

// Initialize CAN device                
controlAllegroHand *canDevice;



// Called when a desired joint position message is received
void SetjointCallback(const sensor_msgs::JointState& msg)
{
        mutex->lock();
        for(int i=0;i<DOF_JOINTS;i++) desired_position[i] = msg.position[i];
        mutex->unlock();        
}

// Called when an external (string) message is received
void extCmdCallback(const std_msgs::String::ConstPtr& msg)
{
        ROS_INFO("CTRL: Processing external command");
        ext_cmd = msg->data.c_str();

        // Compare the message received to an expected input
        if (ext_cmd.compare("comparisonString") == 0)
        {
                // Do something
        }    
        else
        {
                // Do something else
        }       
}


// In case of the Allegro Hand, this callback is processed every 0.003 seconds
void timerCallback(const ros::TimerEvent& event)
{
        // Calculate loop time;
        tnow = ros::Time::now();
        dt = 1e-9*(tnow - tstart).nsec;
        tstart = tnow;
                
        // save last joint position for velocity calc
        for(int i=0; i<DOF_JOINTS; i++) previous_position[i] = current_position[i];
                
                
                
                
/*  ================================= 
    =       CAN COMMUNICATION       = 
    ================================= */        
        canDevice->setTorque(desired_torque);           // WRITE joint torque
        lEmergencyStop = canDevice->update();           // Returns -1 in case of an error
        canDevice->getJointInfo(current_position);      // READ current joint positions

                
                
                                
        // Stop program and shutdown node when Allegro Hand is switched off
        if( lEmergencyStop < 0 )
        {
                ROS_ERROR("\n\nAllegro Hand Node is Shutting Down! (Emergency Stop)\n");
                ros::shutdown();
        }


/*  ================================= 
        =       LOWPASS FILTERING       =   
        ================================= */
        for(int i=0; i<DOF_JOINTS; i++)    
        {
                current_position_filtered[i] = (0.6*current_position_filtered[i]) + (0.198*previous_position[i]) + (0.198*current_position[i]);
                current_velocity[i] = (current_position_filtered[i] - previous_position_filtered[i]) / dt;
                current_velocity_filtered[i] = (0.6*current_velocity_filtered[i]) + (0.198*previous_velocity[i]) + (0.198*current_velocity[i]);
        }       





    if(frame>100) // give the low pass filters 100 iterations (0.03s) to build up good data.
        {

/*  ================================= 
        =  COMPUTE CONTROL TORQUE HERE  =               // current_position_filtered --> desired_torque //
        ================================= */    

        }





        // PUBLISH current position, velocity and effort (torque)
        msgJoint.header.stamp           = tnow; 
        for(int i=0; i<DOF_JOINTS; i++)
        {
                msgJoint.position[i]    = current_position_filtered[i];
                msgJoint.velocity[i]    = current_velocity_filtered[i];
                msgJoint.effort[i]              = desired_torque[i];
        }
        joint_state_pub.publish(msgJoint);
                
                
        frame++;

} // end timerCallback








int main(int argc, char** argv)
{
        using namespace std;
        
        ros::init(argc, argv, "allegro_hand_core");
        ros::Time::init();
        
        ros::NodeHandle nh;

        // Setup timer callback (ALLEGRO_CONTROL_TIME_INTERVAL = 0.003)
        ros::Timer timer = nh.createTimer(ros::Duration(0.003), timerCallback);

        mutex = new boost::mutex();

        // Publisher and Subscribers
        joint_state_pub = nh.advertise<sensor_msgs::JointState>(JOINT_STATE_TOPIC, 3);
        joint_cmd_sub = nh.subscribe(JOINT_CMD_TOPIC, 3, SetjointCallback);
        external_cmd_sub = nh.subscribe(EXT_CMD_TOPIC, 1, extCmdCallback);
        
        // Create arrays 16 long for each of the four joint state components
        msgJoint.position.resize(DOF_JOINTS);
        msgJoint.velocity.resize(DOF_JOINTS);
        msgJoint.effort.resize(DOF_JOINTS);
        msgJoint.name.resize(DOF_JOINTS);

        // Joint names (for use with joint_state_publisher GUI - matches URDF)
        for(int i=0; i<DOF_JOINTS; i++) msgJoint.name[i] = jointNames[i];       

        
        // Get Allegro Hand information from parameter server
        // This information is found in the Hand-specific "zero.yaml" file from the allegro_hand_description package    
        string robot_name, whichHand, manufacturer, origin, serial;
        double version;
        ros::param::get("~hand_info/robot_name",robot_name);
        ros::param::get("~hand_info/which_hand",whichHand);
        ros::param::get("~hand_info/manufacturer",manufacturer);
        ros::param::get("~hand_info/origin",origin);
        ros::param::get("~hand_info/serial",serial);
        ros::param::get("~hand_info/version",version);
        

        // Initialize CAN device
        canDevice = new controlAllegroHand();
        canDevice->init();
        usleep(3000);
        
        // Dump Allegro Hand information to the terminal        
        cout << endl << endl << robot_name << " v" << version << endl << serial << " (" << whichHand << ")" << endl << manufacturer << endl << origin << endl << endl;

        // Initialize torque at zero
        for(int i=0; i<16; i++) desired_torque[i] = 0.0;

        // Start ROS time
        tstart = ros::Time::now();

        // Starts control loop, message pub/subs and all other callbacks
        ros::spin();                    

        // Clean shutdown: shutdown node, shutdown can, be polite.
        nh.shutdown();
        delete canDevice;
        printf("\nAllegro Hand Node has been shut down. Bye!\n\n");
        return 0;
        
}