bhand_node.py

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#!/usr/bin/env python
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# Copyright (c) 2014, Robotnik Automation SLL
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import rospy 
from pyHand_api import *

from std_msgs.msg import String
from bhand_controller.msg import State, TactileArray, Service
from bhand_controller.srv import Actions, SetControlMode
from sensor_msgs.msg import JointState

import time, threading
import math

DEFAULT_FREQ = 100.0
MAX_FREQ = 250.0


CONTROL_MODE_POSITION = "POSITION"
CONTROL_MODE_VELOCITY = "VELOCITY"

WATCHDOG_VELOCITY = 0.1 # Max time (seconds) between velocity commands before stopping the velocity

# class to save the info of each joint
class JointHand:
        
        def __init__(self, id, name):
                self.id = id
                self.joint_name = name
                self.desired_position = 0.0
                self.desired_velocity = 0.0
                self.real_position = 0.0
                self.real_velocity = 0.0
                
        
# Class control the Barrett Hand
class BHand:
        
        def __init__(self, args):
                
                self.port = args['port']
                self.topic_state_name = args['topic_state']
                self.desired_freq = args['desired_freq'] 
                if self.desired_freq <= 0.0 or self.desired_freq > MAX_FREQ:
                        rospy.loginfo('%s::init: Desired freq (%f) is not possible. Setting desired_freq to %f'%(rospy.get_name(), self.desired_freq, DEFAULT_FREQ))
                        self.desired_freq = DEFAULT_FREQ
                self.tactile_sensors = args['tactile_sensors'] 
                self.real_freq = 0.0
                
                joint_ids_arg = args['joint_ids']
                joint_names_arg = args['joint_names']
                # Control mode
                self.control_mode = args['control_mode']
                if self.control_mode != CONTROL_MODE_POSITION and self.control_mode != CONTROL_MODE_VELOCITY:
                        rospy.loginfo('%s: init: setting control mode by default to %s'%(rospy.get_name(), CONTROL_MODE_POSITION))
                        self.control_mode = CONTROL_MODE_POSITION
                
                self.state = State.INIT_STATE
                # flag to control the initialization of CAN device 
                self.can_initialized = False
                # flag to control the initialization of the hand
                self.hand_initialized = False
                # flag to control the initialization of ROS stuff
                self.ros_initialized = False
                # flag to control that the control loop is running
                self.running = False
                
                self.time_sleep = 1.0
                # BHand library object
                self.hand = pyHand(self.port)
                # Current state of the joints
                self.joint_state = JointState()
                # Msg to publish the tactile array
                self.msg_tact_array = TactileArray()
                # State msg to publish
                self.msg_state = State()
                # Timer to publish state
                self.publish_state_timer = 1
                # Flag active after receiving a new command
                self.new_command = False
                # Flag active for reading temperature
                self.temp_command = False
                # Used to read one temperature sensor every time
                self.temp_current_sensor = 0
                # Total number of temperature sensors 
                self.temp_sensor_number = 8
                # Frequency to read temperature
                self.temp_read_timer = 5# seconds
                # Counts the number of CAN errors before switching to FAILURE
                self.can_errors = 0
                # Max. number of CAN errors 
                self.max_can_errors = 5
                # Flag to perform a failure recover
                self.failure_recover = False
                # Timer to try the FAILURE RECOVER
                self.failure_recover_timer = 5  
                # Timer to save the last command 
                self.timer_command = time.time()
                self.watchdog_command = float(WATCHDOG_VELOCITY)
                
                # List where saving the required actions
                self.actions_list = []
                # Mode of the hand to perform the grasp
                self.grasp_mode = Service.SET_GRASP_1
                
                #print 'Control mode = %s'%self.control_mode
                
                # Data structure to link assigned joint names with every real joint
                # {'ID': ['joint_name', index], ...}
                #self.joint_names = {'F1': ['j12_joint',  0], 'F1_TIP': ['j13_joint', 1] , 'F2': ['j22_joint', 2], 'F2_TIP': ['j23_joint', 3],  'F3': ['j32_joint', 4], 'F3_TIP': ['j33_joint', 5], 'SPREAD_1': ['j11_joint', 6], 'SPREAD_2': ['j21_joint', 7]}
                # {'ID': ['joint_name'], ...}
                #'j33_joint' -> F3-Fingertip
                #'j32_joint' -> F3-Base
                #
                #'j11_joint' -> F1-Spread
                #'j12_joint' -> F1-Base
                #'j13_joint' -> F1-Fingertip
                #
                #'j21_joint' -> F2-Spread
                #'j22_joint' -> F2-Base
                #'j23_joint' -> F2-Fingertip
                
                self.joint_names = {}
                
                for i in range(len(joint_ids_arg)):
                        self.joint_names[joint_ids_arg[i]] = [joint_names_arg[i], i]
                
                print   self.joint_names
                
                # {'ID': [Puck_temp, motor_temp], ..}
                self.temperatures = {'F1': [0.0,  0.0], 'F2': [0.0,  0.0], 'F3': [0.0,  0.0], 'SPREAD': [0.0,  0.0]}
                
                # Inits joint state (FOR PUBLISHING)
                k = 0
                for i in self.joint_names:
                        self.joint_state.name.append(self.joint_names[i][0])
                        self.joint_names[i][1] = k # Updates the index
                        k = k + 1
                        #self.joint_state.name = ['j33_joint', 'j32_joint', 'j21_joint', 'j22_joint', 'j23_joint', 'j11_joint', 'j12_joint', 'j13_joint']
                        self.joint_state.position.append(0.0)
                        self.joint_state.velocity.append(0.0)
                        self.joint_state.effort.append(0.0)
                
                #  Saves the desired position of the joints {'joint_name': value, ...}
                self.desired_joints_position = {self.joint_names['F1'][0]: 0.0, self.joint_names['F2'][0]: 0.0, self.joint_names['F3'][0]: 0.0, self.joint_names['SPREAD_1'][0]: 0.0, self.joint_names['SPREAD_2'][0]: 0.0}
                self.desired_joints_velocity = {self.joint_names['F1'][0]: 0.0, self.joint_names['F2'][0]: 0.0, self.joint_names['F3'][0]: 0.0, self.joint_names['SPREAD_1'][0]: 0.0, self.joint_names['SPREAD_2'][0]: 0.0}
                # Saves the last sent velocity
                self.sent_joints_velocity = {self.joint_names['F1'][0]: 0.0, self.joint_names['F2'][0]: 0.0, self.joint_names['F3'][0]: 0.0, self.joint_names['SPREAD_1'][0]: 0.0, self.joint_names['SPREAD_2'][0]: 0.0}
                
                self.t_publish_state = threading.Timer(self.publish_state_timer, self.publishROSstate)
                self.t_read_temp = threading.Timer(self.temp_read_timer, self.readTemp)
                
                rospy.loginfo('%s: port %s, freq = %d, topic = %s, tactile_sensors = %s'%(rospy.get_name() , self.port, self.desired_freq, self.topic_state_name, self.tactile_sensors))
        
        
        def setup(self):
                '''
                        Initializes de hand
                        @return: True if OK, False otherwise
                '''
                if self.can_initialized or self.hand.initialize() == True:
                        self.can_initialized = True
                        return 0
                else:
                        self.hand.can_uninit()
                        rospy.logerr('%s: Error initializing the hand'%rospy.get_name() )
                        return -1
                
                
        def rosSetup(self):
                '''
                        Creates and inits ROS components
                '''
                if self.ros_initialized:
                        return 0
                        
                #self._enable_disable_service = rospy.Service('%s/enable_disable'%rospy.get_name(), enable_disable, self.enableDisable)
                # PUBLISHERS
                self._state_publisher = rospy.Publisher('%s/state'%rospy.get_name(), State)
                self._joints_publisher = rospy.Publisher('/joint_states', JointState)
                self._tact_array_publisher = rospy.Publisher('%s/tact_array'%rospy.get_name(), TactileArray)
                # SUBSCRIBERS
                self._joints_subscriber = rospy.Subscriber('%s/command'%rospy.get_name(), JointState, self.commandCallback)
                
                # SERVICES
                self._hand_service = rospy.Service('%s/actions'%rospy.get_name(), Actions, self.handActions)
                self._set_control_mode_service = rospy.Service('%s/set_control_mode'%rospy.get_name(), SetControlMode, self.setControlModeServiceCb)
        
                self.ros_initialized = True
                
                self.publishROSstate()
                
                return 0
                
                
        def shutdown(self):
                '''
                        Shutdowns device
                        @return: 0 if it's performed successfully, -1 if there's any problem or the component is running
                '''
                if self.running or not self.can_initialized:
                        return -1
                rospy.loginfo('%s::shutdown'%rospy.get_name())
                self.setControlMode('POSITION')
                # Performs Hand shutdown
                self.hand.can_uninit()
                # Cancels current timers
                self.t_publish_state.cancel()
                self.t_read_temp.cancel()
                
                
                self.can_initialized = False
                self.hand_initialized = False
                
                return 0
        
        
        def rosShutdown(self):
                '''
                        Shutdows all ROS components
                        @return: 0 if it's performed successfully, -1 if there's any problem or the component is running
                '''
                if self.running or not self.ros_initialized:
                        return -1
                
                # Performs ROS topics & services shutdown
                self._state_publisher.unregister()
                self._joints_publisher.unregister()
                self._tact_array_publisher.unregister()
                self._joints_subscriber.unregister()
                self._set_control_mode_service.shutdown()
                self._hand_service.shutdown()
                
                self.ros_initialized = False
                
                return 0
                        
        
        def stop(self):
                '''
                        Creates and inits ROS components
                '''
                self.running = False
                
                return 0
        
        
        def start(self):
                '''
                        Runs ROS configuration and the main control loop
                        @return: 0 if OK
                '''
                self.rosSetup()
                
                if self.running:
                        return 0
                        
                self.running = True
                
                self.controlLoop()
                
                return 0
        
        
        def controlLoop(self):
                '''
                        Main loop of the component
                        Manages actions by state
                '''
                
                while self.running and not rospy.is_shutdown():
                        t1 = time.time()
                        
                        if self.state == State.INIT_STATE:
                                self.initState()
                                
                        elif self.state == State.STANDBY_STATE:
                                self.standbyState()
                                
                        elif self.state == State.READY_STATE:
                                self.readyState()
                                
                        elif self.state == State.EMERGENCY_STATE:
                                self.emergencyState()
                                
                        elif self.state == State.FAILURE_STATE:
                                self.failureState()
                                
                        elif self.state == State.SHUTDOWN_STATE:
                                self.shutdownState()
                                
                        self.allState()
                        
                        t2 = time.time()
                        tdiff = (t2 - t1)
                        
                        
                        t_sleep = self.time_sleep - tdiff
                        #print 't_sleep = %f secs'%(t_sleep)
                        if t_sleep > 0.0:
                                #print 't_sleep = %f secs'%(self.time_sleep)
                                rospy.sleep(t_sleep)
                        
                        t3= time.time()
                        self.real_freq = 1.0/(t3 - t1)
                
                self.running = False
                # Performs component shutdown
                self.shutdownState()
                # Performs ROS shutdown
                self.rosShutdown()
                rospy.loginfo('%s::controlLoop: exit control loop'%rospy.get_name())
                
                return 0
                
        
        
        def rosPublish(self):
                '''
                        Publish topics at standard frequency
                '''
                #self._state_publisher.publish(self.getState())
                
                
                t = rospy.Time.now()
                
                self.joint_state.header.stamp = t
                self._joints_publisher.publish(self.joint_state)
                
                if self.tactile_sensors:
                        self.msg_tact_array.header.stamp = t
                        self._tact_array_publisher.publish(self.msg_tact_array)
                        
                return 0
                
        
        
        def initState(self):
                '''
                        Actions performed in init state
                '''
                error = 0
                if not self.can_initialized:
                        ret = self.setup()
                        if ret == -1:
                                error = 1
                                
                if self.hand_initialized and self.can_initialized:
                        self.switchToState(State.STANDBY_STATE)
                
                self.canError(error)
                
                return
        
        def standbyState(self):
                '''
                        Actions performed in standby state
                '''
                #self.hand.close_grasp()
                self.switchToState(State.READY_STATE)
                
                return
        
        
        def readyState(self):
                '''
                        Actions performed in ready state
                '''
                f1_index = self.joint_names['F1'][1]
                f2_index = self.joint_names['F2'][1]
                f3_index = self.joint_names['F3'][1]
                f1_tip_index = self.joint_names['F1_TIP'][1]
                f2_tip_index = self.joint_names['F2_TIP'][1]
                f3_tip_index = self.joint_names['F3_TIP'][1]
                spread1_index = self.joint_names['SPREAD_1'][1]
                spread2_index = self.joint_names['SPREAD_2'][1]
                errors = 0
                
                
                try:
                        # Reads position
                        self.hand.read_packed_position(SPREAD)
                        self.hand.read_packed_position(FINGER1)
                        self.hand.read_packed_position(FINGER2)
                        self.hand.read_packed_position(FINGER3)
                        
                        # Reads strain
                        self.hand.read_strain(FINGER1)
                        self.hand.read_strain(FINGER2)
                        self.hand.read_strain(FINGER3)
                        
                        # Reads temperature
                        if self.temp_command:
                                self.hand.read_temp(FINGER1)
                                self.hand.read_temp(FINGER2)
                                self.hand.read_temp(FINGER3)
                                self.hand.read_temp(SPREAD)
                                self.hand.read_therm(FINGER1)
                                self.hand.read_therm(FINGER2)
                                self.hand.read_therm(FINGER3)
                                self.hand.read_therm(SPREAD)
                                self.initReadTempTimer()
                        
                        # Reads tactile sensor cells
                        if self.tactile_sensors:
                                self.hand.read_full_tact(SPREAD)
                                self.hand.read_full_tact(FINGER1)
                                self.hand.read_full_tact(FINGER2)
                                self.hand.read_full_tact(FINGER3)
                                
                                
                except Exception, e:
                        rospy.logerr('%s::readyState: error getting info: %s'%(rospy.get_name(), e))
                        errors = errors + 1
                
                # Predefined actions
                if len(self.actions_list) > 0:
                        action = self.actions_list[0]
                        # Removes action from list 
                        self.actions_list.remove(action)
                        
                        # Actions performed in CONTROL POSITION
                        if self.control_mode == CONTROL_MODE_VELOCITY:
                                self.setControlMode(CONTROL_MODE_POSITION)
                        
                        if action == Service.CLOSE_GRASP:
                                self.closeFingers(3.14)
                        
                        if action == Service.CLOSE_HALF_GRASP:
                                self.closeFingers(1.57)
                                
                        elif action == Service.OPEN_GRASP:
                                self.openFingers()
                                
                        elif action == Service.SET_GRASP_1:
                                if self.joint_state.position[f1_index] > 0.1 or self.joint_state.position[f2_index] > 0.1 or self.joint_state.position[f3_index] > 0.1:
                                        #rospy.logerr('BHand::ReadyState: Service SET_GRASP 1 cannot be performed. Rest of fingers have to be on zero position')
                                        self.openFingers()
                                        time.sleep(2.0)
                                
                                self.desired_joints_position['SPREAD_1'] = 0.0
                                self.desired_joints_position['SPREAD_2'] = 0.0
                                self.hand.move_to(SPREAD, self.hand.rad_to_enc(self.desired_joints_position['SPREAD_1'], BASE_TYPE), False)
                                self.grasp_mode = action
                                        
                        elif action == Service.SET_GRASP_2:
                                if self.joint_state.position[f1_index] > 0.1 or self.joint_state.position[f2_index] > 0.1 or self.joint_state.position[f3_index] > 0.1:
                                        #rospy.logerr('BHand::ReadyState: Service SET_GRASP 2 cannot be performed. Rest of fingers have to be on zero position')
                                        self.openFingers()
                                        time.sleep(2.0)
                                #else:
                                self.desired_joints_position['SPREAD_1'] = 3.14
                                self.desired_joints_position['SPREAD_2'] = 3.14
                                self.hand.move_to(SPREAD, self.hand.rad_to_enc(self.desired_joints_position['SPREAD_1'], BASE_TYPE), False)
                                self.grasp_mode = action
                        
                # NO pre-defined actions                        
                else: 
                        if self.control_mode == CONTROL_MODE_POSITION:
                        
                                # Moves joints to desired pos
                                if self.new_command:
                                        try:
                                                f1_joint = self.joint_names['F1'][0]            
                                                if self.desired_joints_position[f1_joint] != self.joint_state.position[f1_index]:
                                                        #print 'moving joint %s to position  %f'%(self.joint_state.name[0], self.desired_joints_position['j12_joint'])
                                                        self.hand.move_to(FINGER1, self.hand.rad_to_enc(self.desired_joints_position[f1_joint], BASE_TYPE), False)
                                                
                                                f2_joint = self.joint_names['F2'][0]
                                                if self.desired_joints_position[f2_joint] != self.joint_state.position[f2_index]:
                                                        #print 'moving joint %s to position  %f'%(self.joint_state.name[2], self.desired_joints_position['j22_joint'])
                                                        self.hand.move_to(FINGER2, self.hand.rad_to_enc(self.desired_joints_position[f2_joint], BASE_TYPE), False)
                                                        
                                                f3_joint = self.joint_names['F3'][0]
                                                if self.desired_joints_position[f3_joint] != self.joint_state.position[f3_index]:
                                                        #print 'moving joint %s to position  %f'%(self.joint_state.name[4], self.desired_joints_position['j32_joint'])
                                                        self.hand.move_to(FINGER3, self.hand.rad_to_enc(self.desired_joints_position[f3_joint], BASE_TYPE), False)
                                                        
                                                spread1_joint = self.joint_names['SPREAD_1'][0]
                                                spread2_joint = self.joint_names['SPREAD_2'][0]
                                                if self.desired_joints_position[spread1_joint] != self.joint_state.position[spread1_index]:
                                                        #print 'moving joint %s to position  %f'%(self.joint_state.name[6], self.desired_joints_position['jspread_joint'])
                                                        self.hand.move_to(SPREAD, self.hand.rad_to_enc(self.desired_joints_position[spread1_joint], SPREAD_TYPE), False)
                                                elif self.desired_joints_position[spread2_joint] != self.joint_state.position[spread2_index]:
                                                        #print 'moving joint %s to position  %f'%(self.joint_state.name[6], self.desired_joints_position['jspread_joint'])
                                                        self.hand.move_to(SPREAD, self.hand.rad_to_enc(self.desired_joints_position[spread2_joint], SPREAD_TYPE), False)
                                                
                                        except Exception, e:
                                                rospy.logerr('%s::readyState: error sending command: %s'%(rospy.get_name(), e))
                                                errors = errors + 1
                                        
                                        self.new_command = False
                        
                        else:
                                # VELOCITY CONTROL
                                if ((time.time() - self.timer_command) >= self.watchdog_command):
                                        try:
                                                #rospy.loginfo('BHand::readyState: Watchdog velocity')
                                                self.desired_joints_velocity[self.joint_names['F1'][0]] = 0.0
                                                self.desired_joints_velocity[self.joint_names['F2'][0]] = 0.0
                                                self.desired_joints_velocity[self.joint_names['F3'][0]] = 0.0
                                                self.desired_joints_velocity[self.joint_names['SPREAD_1'][0]] = 0.0
                                                self.desired_joints_velocity[self.joint_names['SPREAD_2'][0]] = 0.0
                                                self.setJointVelocity('F1')
                                                self.setJointVelocity('F2')
                                                self.setJointVelocity('F3')
                                                self.setJointVelocity('SPREAD_1')
                                        except Exception, e:
                                                rospy.logerr('%s::readyState: error sending command: %s'%(rospy.get_name(), e))
                                                errors = errors + 1
                                # Moves joints to desired pos
                                if self.new_command:
                        
                                        try:
                                                self.setJointVelocity('F1')
                                                self.setJointVelocity('F2')
                                                self.setJointVelocity('F3')
                                                self.setJointVelocity('SPREAD_1')
                                                
                                                
                                        except Exception, e:
                                                rospy.logerr('%s::readyState: error sending command: %s'%(rospy.get_name(), e))
                                                errors = errors + 1
                                        
                                        self.new_command = False
                        
                time.sleep(0.002)
                
                # Reads messages from CAN bus
                if self.hand.process_can_messages() != 0:
                        # If it doesn't read any msg, counts as error
                        self.canError(1)
                
                # Updating variables
                # Position
                self.joint_state.position[f1_index], self.joint_state.position[f1_tip_index] = self.hand.get_packed_position(FINGER1)
                self.joint_state.position[f2_index], self.joint_state.position[f2_tip_index] = self.hand.get_packed_position(FINGER2)
                self.joint_state.position[f3_index], self.joint_state.position[f3_tip_index] = self.hand.get_packed_position(FINGER3)
                self.joint_state.position[spread1_index], e = self.hand.get_packed_position(SPREAD)
                self.joint_state.position[spread2_index] = self.joint_state.position[spread1_index]
                
                # Strain
                self.joint_state.effort[f1_index] = self.joint_state.effort[f1_tip_index] = self.strain_to_nm(self.hand.get_strain(FINGER1))
                self.joint_state.effort[f2_index] = self.joint_state.effort[f2_tip_index] = self.strain_to_nm(self.hand.get_strain(FINGER2))
                self.joint_state.effort[f3_index] = self.joint_state.effort[f3_tip_index] = self.strain_to_nm(self.hand.get_strain(FINGER3))
                
                # Temperature
                self.msg_state.temp_f1[1] = self.hand.get_temp(FINGER1)
                self.msg_state.temp_f2[1] = self.hand.get_temp(FINGER2)
                self.msg_state.temp_f3[1] = self.hand.get_temp(FINGER3)
                self.msg_state.temp_spread[1] = self.hand.get_temp(SPREAD)
                self.msg_state.temp_f1[0] = self.hand.get_therm(FINGER1)
                self.msg_state.temp_f2[0] = self.hand.get_therm(FINGER2)
                self.msg_state.temp_f3[0] = self.hand.get_therm(FINGER3)
                self.msg_state.temp_spread[0] = self.hand.get_therm(SPREAD)
                
                # Tactile Sensors
                self.msg_tact_array.finger1 = self.hand.get_full_tact(FINGER1)
                self.msg_tact_array.finger2 = self.hand.get_full_tact(FINGER2)
                self.msg_tact_array.finger3 = self.hand.get_full_tact(FINGER3)
                self.msg_tact_array.palm = self.hand.get_full_tact(SPREAD)
                
                '''     e21, e22 = self.hand.get_packed_position(FINGER2, 1)
                        e31, e32 = self.hand.get_packed_position(FINGER3, 1)
                        espread, e_ = self.hand.get_packed_position(SPREAD, 1)
                        
                        self.joint_state.position[f2_index] = self.hand.enc_to_rad(e21, BASE_TYPE)
                        self.joint_state.position[f2_tip_index] = self.hand.enc_to_rad(e22, TIP_TYPE)
                        self.joint_state.position[f3_index] = self.hand.enc_to_rad(e31, BASE_TYPE)
                        self.joint_state.position[f3_tip_index] = self.hand.enc_to_rad(e32, TIP_TYPE)
                        self.joint_state.position[spread1_index] = self.joint_state.position[spread2_index] = self.hand.enc_to_rad(espread, SPREAD_TYPE)
                '''
                #print 'End loop'
                # Check the CAN bus status
                self.canError(errors)
                
                return
        
        
        def setJointVelocity(self, finger):
                '''
                        Sets the joint velocity of the desired joint
                        Takes the velocity value from the attribute desired_joints_velocity
                        @param joint: finger of the hand (F1, F2, F3, SPREAD)
                        @type joint: string
                '''
                if self.joint_names.has_key(finger):
                        joint = self.joint_names[finger][0]     
                                                
                        if self.desired_joints_velocity[joint] != self.sent_joints_velocity[joint]:
                                        
                                value = self.hand.rad_to_enc(self.desired_joints_velocity[joint], BASE_TYPE) / 1000
                                self.sent_joints_velocity[joint] = self.desired_joints_velocity[joint]  # Saves the last sent ref 
                                #print 'Moving Joint %s at %f rad/s (%d conts/sec)'%(joint, self.desired_joints_velocity[joint], value)
                                
                                if finger == 'F1':
                                        self.hand.set_velocity(FINGER1, value)
                                elif finger == 'F2':
                                        self.hand.set_velocity(FINGER2, value)
                                elif finger == 'F3':
                                        self.hand.set_velocity(FINGER3, value)
                                elif finger == 'SPREAD_1' or finger == 'SPREAD_2':
                                        self.hand.set_velocity(SPREAD, value)
                                                
        
        def shutdownState(self):
                '''
                        Actions performed in shutdown state 
                '''
                print 'shutdownState'
                if self.shutdown() == 0:
                        self.switchToState(State.INIT_STATE)
                
                return
        
        def emergencyState(self):
                '''
                        Actions performed in emergency state
                '''
                
                return
        
        def failureState(self):
                '''
                        Actions performed in failure state
                '''
                if self.failure_recover:
                        # Performs Hand shutdown
                        self.hand.can_uninit()
                        self.can_initialized = False
                        self.switchToState(State.INIT_STATE)
                        self.failure_recover = False
                        self.can_errors = 0
                        
                return
        
        def switchToState(self, new_state):
                '''
                        Performs the change of state
                '''
                if self.state != new_state:
                        self.state = new_state
                        rospy.loginfo('BHand::switchToState: %s', self.stateToString(self.state))
                        
                        if self.state == State.READY_STATE:
                                # On ready state it sets the desired freq.
                                self.time_sleep = 1.0 / self.desired_freq
                                self.initReadTempTimer()
                        elif self.state == State.FAILURE_STATE:
                                # On other states it set 1 HZ frequency
                                self.time_sleep = 1.0
                                self.initFailureRecoverTimer(self.failure_recover_timer)
                        else:
                                # On other states it set 1 HZ frequency
                                self.time_sleep = 1.0
                
                return
                
        def allState(self):
                '''
                        Actions performed in all states
                '''
                self.rosPublish()
                
                return
        
        
        def stateToString(self, state):
                '''
                        @param state: state to convert
                        @type state: bhand_controller.msg.State
                        @returns the equivalent string of the state
                '''
                if state == State.INIT_STATE:
                        return 'INIT_STATE'
                                
                elif state == State.STANDBY_STATE:
                        return 'STANDBY_STATE'
                        
                elif state == State.READY_STATE:
                        return 'READY_STATE'
                        
                elif state == State.EMERGENCY_STATE:
                        return 'EMERGENCY_STATE'
                        
                elif state == State.FAILURE_STATE:
                        return 'FAILURE_STATE'
                        
                elif state == State.SHUTDOWN_STATE:
                        return 'SHUTDOWN_STATE'
                else:
                        return 'UNKNOWN_STATE'
        
        
        def actionsToString(self, action):
                '''
                        @param action: action to convert
                        @type state: bhand_controller.msg.Service
                        @returns the equivalent string of the action
                '''
                if action == Service.INIT_HAND:
                        return 'INIT_HAND'
                                
                elif action == Service.CLOSE_GRASP:
                        return 'CLOSE_GRASP'
                        
                elif action == Service.OPEN_GRASP:
                        return 'OPEN_GRASP'
                        
                elif action == Service.SET_GRASP_1:
                        return 'SET_GRASP_1'
                        
                elif action == Service.SET_GRASP_2:
                        return 'SET_GRASP_2'
                
                elif action == Service.CLOSE_HALF_GRASP:
                        return 'CLOSE_HALF_GRASP'
                        
                else:
                        return 'UNKNOWN_ACTION'
        
        
        def commandCallback(self, data):
                '''
                        Function called when receive a new value
                        @param data: state to convert
                        @type data: sensor_msgs.JointState
                '''
                bingo = False
                
                for i in range(len(data.name)):
                        if self.desired_joints_position.has_key(data.name[i]):
                                self.desired_joints_position[data.name[i]] = data.position[i]
                                self.desired_joints_velocity[data.name[i]] = data.velocity[i]
                                bingo = True
                                
                
                if bingo:
                        self.new_command = True
                        self.timer_command = time.time()
                #print 'commandCallback'
        
        
        def readTemp(self):
                '''
                        Function periodically to enable the read of temperature
                '''
                
                self.temp_current_sensor = self.temp_current_sensor + 1
                
                if self.temp_current_sensor > self.temp_sensor_number:
                        self.temp_current_sensor = 1
                
                self.temp_command = True
                
                
        def initReadTempTimer(self):
                '''
                        Function to start the timer to read the temperature
                '''
                self.temp_command = False
                
                self.t_read_temp = threading.Timer(self.temp_read_timer, self.readTemp)
                self.t_read_temp.start()
        
                
        def publishROSstate(self):
                '''
                        Publish the State of the component at the desired frequency
                '''
                self.msg_state.state = self.state
                self.msg_state.state_description = self.stateToString(self.state)
                self.msg_state.desired_freq = self.desired_freq
                self.msg_state.real_freq = self.real_freq
                self.msg_state.hand_initialized = self.hand_initialized 
                self.msg_state.control_mode = self.control_mode 
                self._state_publisher.publish(self.msg_state)
                
                self.t_publish_state = threading.Timer(self.publish_state_timer, self.publishROSstate)
                self.t_publish_state.start()
        
        
        def strain_to_nm(self, x):
                '''
                Converts from raw encoder unit reading to Newton-meters.

                @param x: value to convert

                @returns nm: the torque value in Newton-meters. 
                '''
                p1 = 2.754e-10
                p2 = -1.708e-06
                p3 = 0.003764
                p4 = -2.85
                nm= p1*x**3 + p2*x**2 + p3*x + p4
                
                return nm
                
                
        def handActions(self, req):
                '''
                Handles the callback to Actions ROS service. Allows a set of predefined actions like init_hand, close_grasp, ...

                @param req: action id to perform
                @type req: bhand_controller.srv.Actions

                @returns: True or false depending on the result
                '''
                if req.action == Service.INIT_HAND:
                        if self.state != State.INIT_STATE:
                                rospy.logerr('%s::handActions: action INIT_HAND not allowed in state %s'%(rospy.get_name() ,self.stateToString(self.state)))
                                
                                return False
                        else:
                                ret = self.hand.init_hand()
                                if ret:
                                        self.hand_initialized = True
                                        rospy.loginfo('%s::handActions: INIT HAND service OK'%rospy.get_name() )
                                        return True
                                else:
                                        rospy.logerr('%s::handActions: error on INIT_HAND service'%rospy.get_name() )
                                        # Set the max number of errors to perform the CAN reinitialization
                                        self.canError(self.max_can_errors + 1)
                                        return False
                        
                if self.state != State.READY_STATE:
                        rospy.logerr('%s::handActions: action not allowed in state %s'%(rospy.get_name(), self.stateToString(self.state)))
                        return False
                else:
                        rospy.loginfo('%s::handActions: Received new action %s'%(rospy.get_name(), self.actionsToString(req.action)))
                        self.actions_list.append(req.action)
                        
                return True


        def canError(self, n):
                '''
                Manages the CAN errors ocurred

                @param n: number of produced
                @type n: int

                @returns: True or false depending on the result
                '''
                
                self.can_errors = self.can_errors + n   
                
                #rospy.loginfo('%s::canError: %d errors on CAN bus'%(rospy.get_name(),self.can_errors)) 
                
                if self.can_errors > self.max_can_errors:
                        rospy.logerr('%s::canError: Errors on CAN bus'%rospy.get_name())
                        self.switchToState(State.FAILURE_STATE)
        
        
        def initFailureRecoverTimer(self, timer = 5):
                '''
                        Function to start the timer to recover from FAILURE STATE
                '''
                t = threading.Timer(timer, self.failureRecover)
                t.start()
        
                
        def failureRecover(self):               
                '''
                        Sets the recovery flag TRUE. Function called after timer
                '''
                self.failure_recover = True
        
        
        def setControlModeServiceCb(self, req):
                '''
                        Sets the hand control mode
                        @param req: Requested service
                        @type req: bhand_controller.srv.SetControlMode
                '''
                if self.state != State.READY_STATE:
                        rospy.logerr('%s:setControlModeServiceCb: bhand is not in a valid state to change the mode'%rospy.get_name() )
                        return False
                        
                if req.mode != CONTROL_MODE_POSITION and req.mode != CONTROL_MODE_VELOCITY:
                        rospy.logerr('%s:setControlModeServiceCb: invalid control mode %s'%(rospy.get_name(), req.mode))
                        return False
                        
                else:
                        if self.setControlMode(req.mode):
                                rospy.loginfo('%s:setControlModeServiceCb: control mode %s set successfully'%(rospy.get_name(), req.mode))
                                return True
                                
                        else:
                                return False
        
        
        def setControlMode(self, mode):         
                '''
                        Configures the hand to work under the desired control mode
                        @param mode: new mode
                        @type mode: string
                '''
                if self.control_mode == mode:
                        return True
                                
                if mode == CONTROL_MODE_POSITION:
                        self.hand.set_mode(HAND_GROUP, 'IDLE')
                        
                        
                elif mode == CONTROL_MODE_VELOCITY:
                        self.hand.set_mode(HAND_GROUP, 'VEL')
                        
                self.control_mode = mode
        
        
        def openFingers(self):
                '''
                        Opens all the fingers
                '''             
                self.desired_joints_position['F1'] = 0.0
                self.desired_joints_position['F2'] = 0.0
                self.desired_joints_position['F3'] = 0.0
                self.hand.move_to(FINGER1, self.hand.rad_to_enc(self.desired_joints_position['F1'], BASE_TYPE), False)
                self.hand.move_to(FINGER2, self.hand.rad_to_enc(self.desired_joints_position['F2'], BASE_TYPE), False)
                self.hand.move_to(FINGER3, self.hand.rad_to_enc(self.desired_joints_position['F3'], BASE_TYPE), False)
                                
        
        def closeFingers(self, value):
                '''
                        Closes all the fingers
                '''             
                self.desired_joints_position['F1'] = value
                self.desired_joints_position['F2'] = value
                self.desired_joints_position['F3'] = value
                self.hand.move_to(FINGER1, self.hand.rad_to_enc(self.desired_joints_position['F1'], BASE_TYPE), False)
                self.hand.move_to(FINGER2, self.hand.rad_to_enc(self.desired_joints_position['F2'], BASE_TYPE), False)
                self.hand.move_to(FINGER3, self.hand.rad_to_enc(self.desired_joints_position['F3'], BASE_TYPE), False)
                
                
                
def main():

        rospy.init_node("bhand_node")
        
        
        _name = rospy.get_name()
        
        arg_defaults = {
          'port':  '/dev/pcan32',
          'topic_state': 'state',
          'desired_freq': DEFAULT_FREQ,
          'tactile_sensors': True,
          'control_mode': 'POSITION',
          'joint_ids': [ 'F1', 'F1_TIP', 'F2', 'F2_TIP', 'F3', 'F3_TIP', 'SPREAD_1', 'SPREAD_2'],
          'joint_names': ['bh_j12_joint', 'bh_j13_joint', 'bh_j22_joint', 'bh_j23_joint', 'bh_j32_joint', 'bh_j31_joint', 'bh_j11_joint', 'bh_j21_joint']
        }
        
        args = {}
        
        for name in arg_defaults:
                try:
                        if rospy.search_param(name): 
                                args[name] = rospy.get_param('%s/%s'%(_name, name)) # Adding the name of the node, because the para has the namespace of the node
                        else:
                                args[name] = arg_defaults[name]
                        #print name
                except rospy.ROSException, e:
                        rospy.logerror('bhand_node: %s'%e)
                        
        #print args
        bhand_node = BHand(args)
        
        rospy.loginfo('bhand_node: starting')

        bhand_node.start()


if __name__ == "__main__":
        main()