intera_interface.gripper

22 """ 23 Interface class for a gripper on the Intera Research Robot. 24 """ 25 MAX_POSITION = 0.041667 26 MIN_POSITION = 0.0 27 MAX_FORCE = 10.0 28 MIN_FORCE = 0.0 29 MAX_VELOCITY = 3.0 30 MIN_VELOCITY = 0.15 31

32 - def __init__(self, side="right", calibrate=True):

33 """ 34 Constructor. 35 36 @type side: str 37 @param side: robot gripper name 38 @type calibrate: bool 39 @param calibrate: Attempts to calibrate the gripper when initializing class (defaults True) 40 """ 41 self.devices = None 42 self.name = '_'.join([side, 'gripper']) 43 self.ee_config_sub = rospy.Subscriber('/io/end_effector/config', IONodeConfiguration, self._config_callback) 44 # Wait for the gripper device status to be true 45 intera_dataflow.wait_for( 46 lambda: not self.devices is None, timeout=5.0, 47 timeout_msg=("Failed to get gripper. No gripper attached on the robot.") 48 ) 49 50 self.gripper_io = IODeviceInterface("end_effector", self.name) 51 if self.has_error(): 52 self.reboot() 53 calibrate = True 54 if calibrate and not self.is_calibrated(): 55 self.calibrate()

56

57 - def _config_callback(self, msg):

58 """ 59 config topic callback 60 """ 61 if msg.devices != []: 62 if str(msg.devices[0].name) == self.name: 63 self.devices = msg

64

65 - def reboot(self):

66 """ 67 Power cycle the gripper, removing calibration information. 68 69 Basic call to the gripper reboot command. Waits for gripper to return 70 ready state but does not clear errors that could occur during boot. 71 72 @rtype: bool 73 @return: True if successfully Rebooted, False otherwise 74 """ 75 return self.gripper_io.set_signal_value("reboot", True)

76

77 - def stop(self):

78 """ 79 Set the gripper to stop executing command at the current 80 position, apply holding force. 81 82 @rtype: bool 83 @return: True if successfully Stopped, False otherwise 84 """ 85 return self.gripper_io.set_signal_value("go", False)

86

87 - def start(self):

88 """ 89 Set the gripper to start executing command at the current 90 position, apply holding force. 91 92 @rtype: bool 93 @return: True if successfully Started, False otherwise 94 """ 95 return self.gripper_io.set_signal_value("go", True)

96

97 - def open(self, position=MAX_POSITION):

98 """ 99 Set the gripper position to open by providing opening position. 100 @type: float 101 @param: the postion of gripper in meters 102 103 @rtype: bool 104 @return: True if successfully set Position, False otherwise 105 """ 106 return self.gripper_io.set_signal_value("position_m", position)

107

108 - def close(self, position=MIN_POSITION):

109 """ 110 Set the gripper position to close by providing closing position. 111 @type: float 112 @param: the postion of gripper in meters 113 114 @rtype: bool 115 @return: True if successfully set Position, False otherwise 116 """ 117 return self.gripper_io.set_signal_value("position_m", position)

118

119 - def has_error(self):

120 """ 121 Returns a bool describing whether the gripper is in an error state. 122 (True: Error detected, False: No errors) 123 124 @rtype: bool 125 @return: True if in error state, False otherwise 126 """ 127 return self.gripper_io.get_signal_value("has_error")

128

129 - def is_ready(self):

130 """ 131 Returns bool describing if the gripper ready, i.e. is 132 calibrated, not busy (as in resetting or rebooting), and 133 not moving. 134 135 @rtype: bool 136 @return: True if in ready state, False otherwise 137 """ 138 return (self.is_calibrated() and not self.has_error() 139 and not self.is_moving())

140

141 - def is_moving(self):

142 """ 143 Returns bool describing if the gripper is moving. 144 145 @rtype: bool 146 @return: True if in moving state, False otherwise 147 """ 148 return self.gripper_io.get_signal_value("is_moving")

149

150 - def is_gripping(self):

151 """ 152 Returns bool describing if the gripper is gripping. 153 154 @rtype: bool 155 @return: True if in gripping state, False otherwise 156 """ 157 return self.gripper_io.get_signal_value("is_gripping")

158

159 - def is_calibrated(self):

160 """ 161 Returns bool describing if the gripper is calibrated. 162 163 @rtype: bool 164 @return: True if successfully calibrated, False otherwise 165 """ 166 return self.gripper_io.get_signal_value("is_calibrated")

167

168 - def calibrate(self):

169 """ 170 Calibrate the gripper in order to set maximum and 171 minimum travel distance. 172 173 @rtype: bool 174 @return: True if successfully calibrating, False otherwise 175 """ 176 return self.gripper_io.set_signal_value("calibrate", True)

177

178 - def get_position(self):

179 """ 180 Returns float describing the gripper position in meters. 181 182 @rtype: float 183 @return: Current Position value in Meters (m) 184 """ 185 return self.gripper_io.get_signal_value("position_response_m")

186

187 - def set_position(self, position):

188 """ 189 Set the position of gripper. 190 @type: float 191 @param: the postion of gripper in meters 192 193 @rtype: bool 194 @return: True if successfully set value, False otherwise 195 """ 196 return self.gripper_io.set_signal_value("position_m", position)

197

198 - def set_velocity(self, speed):

199 """ 200 Set the velocity at which the gripper position movement will execute. 201 @type: float 202 @param: the velocity of gripper in meters per second 203 204 @rtype: float 205 @return: Current Velocity value in Meters / second (m/s) 206 """ 207 return self.gripper_io.set_signal_value("speed_mps", speed)

208

209 - def get_force(self):

210 """ 211 Returns the force sensed by the gripper in estimated Newtons. 212 213 @rtype: float 214 @return: Current Force value in Newton-Meters (N-m) 215 """ 216 return self.gripper_io.get_signal_value("force_response_n")

217

218 - def set_holding_force(self, holding_force):

219 """ 220 Set holding force of successful gripper grasp. 221 222 Set the force at which the gripper will continue applying after a 223 position command has completed either from successfully achieving the 224 commanded position, or by exceeding the moving force threshold. 225 226 @type: float 227 @param: the holding force of gripper in newton 228 229 @rtype: bool 230 @return: True if successfully set value, False otherwise 231 """ 232 return self.gripper_io.set_signal_value("holding_force_n", holding_force)

233

234 - def set_object_weight(self, object_weight):

235 """ 236 Set the weight of the object in kilograms. 237 @type: float 238 @param: the object weight in newton 239 240 @rtype: bool 241 @return: True if successfully set value, False otherwise 242 """ 243 return self.gripper_io.set_signal_value("object_kg", object_weight)

244

245 - def set_dead_zone(self, dead_zone):

246 """ 247 Set the gripper dead zone describing the position error threshold 248 where a move will be considered successful. 249 250 @type: float 251 @param: the dead zone of gripper in meters 252 253 @rtype: bool 254 @return: True if successfully set value, False otherwise 255 """ 256 return self.gripper_io.set_signal_value("dead_zone_m", dead_zone)

Source Code for Module intera_interface.gripper