iRobot%20Create%20Command%20Interface

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iRobot Create Command Interface

• CPSC 601.68/CPSC 599.68
• Rob Kremer
• Department of Computer Science
• University of Calgary

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Anatomy
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Anatomy
Bump Sensors
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Anatomy
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Agent software support sensor tab
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Agent software support sensor tab
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Agent software support execute command
execute takes a string of bytes (in
decimal). Can also prefix a number with "s" to
make it parse it as two bytes (a short).
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Modes

• OFF
• Unresponsive (except START (128))
• Can charge
• PASSIVE
• Sensor status commands
• No Actuator commands
• Can charge
• SAFE ? recommended!
• Sensor status commands
• Actuator commands
• But reverts to PASSIVE if moving forward and any
  cliff sensor is activated any wheel drop sensor
  is activated or the charger is plugged in
• No Charging
• FULL
• Sensor status commands
• Actuator commands
• No Charging

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Modes
START (128)
OFF
PASSIVE
SAFE (131)
FULL (132)
START (128)
START (128)
SAFE (131)
FULL
SAFE
FULL (132)
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Modes WAIT

• A 5th Mode WAIT
• When in WAIT mode the robot does not respond to
  ANY input.
• Goes into WAIT mode for 3 commands (see WAIT
  slide)
• WAIT-DISTANCE
• WAIT-ANGLE
• WAIT-TIME
• WAIT-EVENT
• If the robot is prevented, for some reason, from
  traveling the distance or the angle, it wont
  respond to anything (try the undocumented command
  7).
• Use only in scripts, NOT RECOMMENDED

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Actuators Drive

• DRIVE (137 ltvelocityhighgt ltvelocitylowgt
  ltradiushighgt ltradiuslowgt)
• 2 short (16 bit) parameters
• Each represented by 2 bytes, high byte first (so
  a total of 5 bytes for this command)
• Parameter 1 velocity in mm/sec
• -500 to 500 (-ve means backwards)
• Parameter 2 curve radius in mm
• -2000 to 2000 where -ve means clockwise and ve
  means counterclockwise
• 32768 means go straight
• -1 and 1 mean spin in place clockwise,
  counterclockwise respectively

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Actuators LEDs

• LEDs (139 ltAdvPlaygt ltpowerColorgt ltpowerIntengt)
• AdvPlay
• Bit 1 (2) Play LED
• Bit 3 (8) Advance LED
• PowerColor (0-255)
• 0green 255red
• PowerIntensity (0-255)
• 0off 255full intensity

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Actuators Send IR

• SEND-IR (151 ltIRbytegt)
• Sends a byte using an add-on circuit and a IR LED
• Can be received by the omnidirectional IR
  reciever at the front of the robot
• Could be use to transmit short-distance
  identifiers for each robot
• Does not replace CASA agent communication
  protocols!

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Actuators Songs

• Load a song
• 140 ltsonggt ltlengthgt ltnotegt ltdurationgt
• ltsonggt 0-15
• ltlengthgt number of notes (1/2 of bytes) (up to
  16 notes)
• ltnotegt see table in OI Manual
• ltdurationgt in 1/64 second (31G_at_49.0Hz
  127G_at_12543.9Hz)
• Play a song
• 141 ltsonggt
• Doesnt work if a song is already playing

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Inputs Sensors

• Read Sensors
• 142 ltpacketIDgt
• Packets 0-6 are packet groups (eg 0 is sensors
  7-26, which is 26 bytes some are two-byte
  returns)
• Packets 7-42 are individual sensors
• Either numerical values (1 or 2 bytes) or bitmaps
• See OI Manual
• Also a commands for
• reading a list of sensors (149)
• requesting a continuous stream of packet data
  (148)
• pausing/resuming a stream (150)

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Sensor Groups Packets
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Sensor Single Packets
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Scripts

• Load a script
• 152 ltlengthgt ltopcodegt
• ltlengthgt number of bytes in script (up to 100)
• ltopcodegt OI commands
• Play a script
• 143
• No flow control except for WAIT commands (next
  slide)
• Show script
• 154
• Returns the current script

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Scripts Wait

• Wait time
• 155 lttimegt
• lttimegt in 1/10 sec (resolution of 15ms)
• Wait Distance
• 156 ltdisthighgt ltdistlowgt
• ltdistgt distance in mm. veforward, -veback
• Works for passively rotating the wheels
• Wait Angle
• 157 ltanglehighgt ltanglelowgt
• ltanglegt angle in deg. vecounterclockwise,
  -veclockwise
• Wait Event
• 158 lteventgt
• lteventgt eg 1wheel drop (see table in OI
  Manual, p.16)
• Use -ve for inverse of event (eg -1 wheel drop
  stops)

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Tasks measuring

• You can track the distance traveled by using
  sensor 19 (distance)
• Angle with sensor 20 (angle)
• Note reading these sensors causes them to be
  reset
• Distance (angles) increment for forward
  (counterclockwise) and decrement for backward
  (clockwise)
• Class iRobotCreates regular sensor reading keeps
  an accumulator for distance and angle

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Tasks Following a wall

• You can track along a wall using the wall sensor
  (sensor 8)
• Use Drive straight (137 ltvelocitygt 32687) when
  the wall is there or a wide right curve (137
  ltvelocitygt -2000) when the wall goes away
• You should expect the occasional right-bump
• If you get a left-bumb, youve probably hit a
  corner