allegroNode.cpp

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/*
 * allegroNode.cpp
 *
 *  Created on: Feb 1, 2013
 *  Authors: Alex ALSPACH, Seungsu KIM
 */
 
// JOINT SPACE POSITION CONTROL
// Using  timer 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 "std_msgs/Float32.h"

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

#include "controlAllegroHand.h"


#define RADIANS_TO_DEGREES(radians) ((radians) * (180.0 / M_PI))
#define DEGREES_TO_RADIANS(angle) ((angle) / 180.0 * M_PI)


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

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

double desired_position[DOF_JOINTS]                             = {0.0};
double desired_torque[DOF_JOINTS]                               = {0.0};

double k_p[DOF_JOINTS]                          = { 600.0,  600.0,  600.0, 1000.0,  // Default P Gains for PD Controller
                                                                                600.0,  600.0,  600.0, 1000.0,  // These gains are loaded if the 'gains_pd.yaml' file is not loaded
                                                                                600.0,  600.0,  600.0, 1000.0,
                                                                           1000.0, 1000.0, 1000.0,  600.0 };

double k_d[DOF_JOINTS]                          = {  15.0,   20.0,   15.0,   15.0,  // Default D Gains for PD Controller
                                                                                 15.0,   20.0,   15.0,   15.0,  // These gains are loaded if the 'gains_pd.yaml' file is not loaded
                                                                                 15.0,   20.0,   15.0,   15.0,
                                                                                 30.0,   20.0,   20.0,   15.0 };
                
                                                                        
double home_pose[DOF_JOINTS]            = {   0.0,  -10.0,   45.0,   45.0,  // Default (HOME) position (degrees)
                                                                                  0.0,  -10.0,   45.0,   45.0,  // This position is loaded and set upon system start
                                                                                  5.0,   -5.0,   50.0,   45.0,  // if no 'initial_position.yaml' parameter is loaded.
                                                                             60.0,   25.0,   15.0,   45.0 };


std::string pGainParams[DOF_JOINTS] = { "~gains_pd/p/j00", "~gains_pd/p/j01", "~gains_pd/p/j02", "~gains_pd/p/j03", 
                                                                                "~gains_pd/p/j10", "~gains_pd/p/j11", "~gains_pd/p/j12", "~gains_pd/p/j13",
                                                                                "~gains_pd/p/j20", "~gains_pd/p/j21", "~gains_pd/p/j22", "~gains_pd/p/j23", 
                                                                                "~gains_pd/p/j30", "~gains_pd/p/j31", "~gains_pd/p/j32", "~gains_pd/p/j33"};

std::string dGainParams[DOF_JOINTS] = { "~gains_pd/d/j00", "~gains_pd/d/j01", "~gains_pd/d/j02", "~gains_pd/d/j03", 
                                                                                "~gains_pd/d/j10", "~gains_pd/d/j11", "~gains_pd/d/j12", "~gains_pd/d/j13",
                                                                                "~gains_pd/d/j20", "~gains_pd/d/j21", "~gains_pd/d/j22", "~gains_pd/d/j23", 
                                                                                "~gains_pd/d/j30", "~gains_pd/d/j31", "~gains_pd/d/j32", "~gains_pd/d/j33"};
                                                                                
std::string initialPosition[DOF_JOINTS] = {     "~initial_position/j00", "~initial_position/j01", "~initial_position/j02", "~initial_position/j03", 
                                                                                        "~initial_position/j10", "~initial_position/j11", "~initial_position/j12", "~initial_position/j13",
                                                                                        "~initial_position/j20", "~initial_position/j21", "~initial_position/j22", "~initial_position/j23", 
                                                                                        "~initial_position/j30", "~initial_position/j31", "~initial_position/j32", "~initial_position/j33"};                                                                            


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::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;
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;
        
        //if ((1/dt)>400)
        //      printf("%f\n",(1/dt-333.33333));
        
                
        // save last iteration info
        for(int i=0; i<DOF_JOINTS; i++)
        {
                previous_position[i] = current_position[i];
                previous_position_filtered[i] = current_position_filtered[i];
                previous_velocity[i] = current_velocity[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]);
        }       
        
        
        
/*  ================================= 
    =        POSITION CONTROL       =   
    ================================= */
    if(frame>100) // give the low pass filters 100 iterations (0.03s) to build up good data.
    {   
                for(int i=0; i<DOF_JOINTS; i++)    
                {
                        desired_torque[i] = k_p[i]*(desired_position[i]-current_position_filtered[i]) - k_d[i]*current_velocity_filtered[i];
                        desired_torque[i] = desired_torque[i]/800.0;
                }
        }               


        // 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);


        // set gains_pd via gains_pd.yaml or to defaul values
        if (ros::param::has("~gains_pd"))
        {
                ROS_INFO("\n\nCTRL: PD gains loaded from param server.\n");
                for(int i=0; i<DOF_JOINTS; i++)
                {
                        ros::param::get(pGainParams[i], k_p[i]);
                        ros::param::get(dGainParams[i], k_d[i]);
                        //printf("%f ", k_p[i]);
                }
                //printf("\n");
        }
        else
        {
                // gains will be loaded every control iteration
                ROS_WARN("\n\nCTRL: PD gains not loaded.\nCheck launch file is loading /parameters/gains_pd.yaml\nloading default PD gains...\n");
        }


        // set initial position via initial_position.yaml or to defaul values
        if (ros::param::has("~initial_position"))
        {
                ROS_INFO("\n\nCTRL: Initial Pose loaded from param server.\n");
                for(int i=0; i<DOF_JOINTS; i++)
                {
                        ros::param::get(initialPosition[i], desired_position[i]);
                        desired_position[i] = DEGREES_TO_RADIANS(desired_position[i]);
                }
        }
        else
        {
                ROS_WARN("\n\nCTRL: Initial postion not loaded.\nCheck launch file is loading /parameters/initial_position.yaml\nloading Home position instead...\n");
                // Home position
                for(int i=0; i<DOF_JOINTS; i++) desired_position[i] = DEGREES_TO_RADIANS(home_pose[i]);                                                                         
        }


        // 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;

        // 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;
        
}