Robot Mower Communications Standard

Robot Mower Communications Standard (RMCS)

Describes message format used to externally control a robot mower (e.g. Ardumower-based) using a serial line (PC/Raspberry/Android etc.)

Requirements

• Serial interface (or serial USB)
• ...

Message format

NMEA 0183 compatible format (ASCII encoded)

message structure: $IDMSG,data,<cr><lf>

message components:

• $: start of message symbol
• ID: device ID (the destination of a command message or source of an event message) - examples: RM (robot mower), DW (ranging beacons), ...
• MSG: message type (see below)
• data: comma separated message data (see below) - if a value is not existing it should be empty
• <cr><lf>: end of message symbol

example: $RMSEN,1,1,,,,0,1,,0,179.8,,,0,0<cr><lf>

Messages

• $RMMOW: Set mowing state command (start mowing, stop mowing, go to docking station)
• $RMSTA: Robot state event (robot state, errors, battery, charger)
• $RMSEN: Robot sensor data event (sensor values)
• $RMTRG: Robot sensor trigger event (sensor trigger counters)
• $RMCFG: Robot mower configuration event (protocol version, available sensors)
• $RMMOV: Move robot until sensor trigger command
• $RMKOA: Keep ongoing action command (mower communications saftety)
• $DWDAT: beacons ranging data event (e.g. DW1000)

Set mowing state command (start,stop,dock)

$RMMOW,s<cr><lf>

• s: stop mowing (0), start mowing (1), go to docking station (2)

Robot state event (robot state, errors, battery, charger)

$RMSTA,ts,s,e,b,bl,c,h,l,r<cr><lf>

• ts: timestamp ms
• s: robot state: stopped (0), mowing (1), busy (2), error (3), going to dock (4)
• o: docking state: not docked (0), docked (1)
• e: error code
• b: battery percent
• bl: battery low (0/1)
• c: charging percent
• h: absolute compass heading in degree
• l: left odometry counter
• r: right odometry counter

Robot sensor data event (sensor values)

$RMSEN,ts,bl,br,bc,pfl,pfr,pfc,prl,prr,prc,ih,ip,ir,ga,go,ul,ur,uc<cr><lf>

• ts: timestamp ms
• bl: bumperLeft
• br: bumperRight
• bc: bumperCenter
• pfl: perimeterFrontLeft
• pfr: perimeterFrontRight
• pfc: perimeterFrontCenter
• prl: perimeterRearLeft
• prr: perimeterRearRight
• prc: perimeterRearCenter
• ih: IMUcompassHeading degree
• ip: IMUpitch degree
• pr: IMUroll degree
• ga: GPSlatitude
• go: GPSlongitude
• ul: ultrasonicLeft
• ur: ultrasonicRight
• uc: ultrasonicCenter

Robot sensor trigger event (sensor trigger counters)

$RMTRG,ts,ml,mr,bl,br,bc,pfl,pfr,pfc,prl,prr,prc,t,ul,ur,uc<cr><lf>

• ts: timestamp ms
• ml: motorLeftStall
• mr: motorRightStall
• bl: bumperLeft
• br: bumperRight
• bc: bumperCenter
• pfl: perimeterFrontLeft
• pfr: perimeterFrontRight
• pfc: perimeterFrontCenter
• prl: perimeterRearLeft
• prr: perimeterRearRight
• prc: perimeterRearCenter
• t: robot orientation tilt
• ul: ultrasonicLeft
• ur: ultrasonicRight
• uc: ultrasonicCenter

Robot mower configuration event (protocol version, type of sensors)

$RMCFG,p,m,d,pfl,pfr,pfc,prl,prr,prc,ih,ip,o,g,ul,ur,uc<cr><lf>

• p: robot is using protocol version (1)
• m: robot requires minimum protocol version (1)
• d: Docking station available (1/0)
• pfl: perimeterFrontLeft available (1/0)
• pfr: perimeterFrontRight available (1/0)
• pfc: perimeterFrontCenter available (1/0)
• prl: perimeterRearLeft available (1/0)
• prr: perimeterRearRight available (1/0)
• prc: perimeterRearCenter available (1/0)
• ih: IMU compass available (1/0)
• ip: IMU pitch/roll available (1/0)
• o: Odometry available (1/0)
• g: GPS available (1/0)
• ul: ultrasonicLeft available (1/0)
• ur: ultrasonicRight available (1/0)
• uc: ultrasonicCenter available (1/0)

Move robot until sensor trigger command

This command is used to control the robot movements directly.

$RMMOV,m,l,r,p,i,d,o<cr><lf>

• m: mowing motor on (1) or off (0)
• l: left motor target ticks per frame
• r: right motor target ticks per frame
• p: PID_Kp
• i: PID_Ki
• d: PID_Kd
• o: PID_Ko

Keep ongoing action command (mower communications saftety)

This command is used to control the motors directly. The mower will stop motors if not receiving another message within 2 seconds.

$RMKOA<cr><lf>

Beacons ranging data event (e.g. DW1000)

$DWDAT,t,b1,b2,b3,b4,...<cr><lf>

• t: timestamp ms
• b1,b2,b3,b4,...: beacon ranging in meter

Proprietary

• Any proprietary messages not defined by this protocol