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Mikołaj Kordowski edited this page Dec 16, 2022 · 19 revisions

Client interact with simulation via 2 different channels for video and control.

  • video default port is 44209
  • control default port is 44210

Packets structure

All packets are TCP/IP. Data length is equal to 0 when packet doesn't have data. Data length is in little endian.
IMPORTANT Video request packet is only 1 byte long, it is just packet type byte!

Packet type Packet flag Data length as int32 Data
1 byte 1 byte 4 bytes n bytes

Flags

Value Abbreviation Description
0 NONE No flags
1 SERVER_ECHO If client packet has this flag, server will respond with additional ACK packet
2 DO_NOT_LOG_PACKET Information that the packet should not be logged (for very repetitive packets like GET_SENS. Server will not log this packet in log file
128 TEST Test flag

Simulation control

This channel is responsible for controlling simulation: steering the robot, recording data etc. Not all packets include data so see packets structure. All non-binary data is in ASCII JSON format. All packets types are listed in the table below.

Packet types bytes are groped by activity they are connected with:

  • 0x00 to 0x9F unused
  • 0xA0 to 0xAF motors
  • 0xB0 to 0xBF sensors
  • 0xC0 to 0xCF simulation
  • 0xD0 to 0xDF data (e.g. getting object detection)
  • 0xE0 to 0xEF unused
  • 0xF0 to 0xFF unused

If packet is GET_* client cannot change the parameter.
If packet is SET_* client can request the current value (with data length equals to zero) apart from changing it.
If packet is send without data, server will respond with current values e.g.
response to SET_CONTROL_MODE request without data will be the current mode.

Byte Abbreviation Description JSON from client JSON from server Working
0xA0 SET_MTR Sets motor power {FLH, FLV, BLV, BLH, FRH, FRV, BRV, BRH} Yes
0xA1 ARM_MTR Arms motors Yes
0xA2 DISARM_MTR Disarms motors Yes
0xA3 SET_CONTROL_MODE Sets control mode mode Yes
0xA4 SET_ACRO Sets Acro mode values {rotSpeed, vel}
0xA5 SET_STABLE Sets Stable mode values {rot, vel, depth} Yes
0xA6 SET_PID Sets motors PIDs {roll, pitch, yaw, depth, rollSpeed, pitchSpeed, yawSpeed} Yes
0xB0 GET_SENS Gets sensors read outs {rot, rotSpeed, accel, rotAccel, baro} Yes
0xB1 GET_DEPTH Requests depth texture depth Yes
0xB2 GET_DEPTH_BYTES Requests depth texture binary data Yes
0xB3 GET_VIDEO_BYTES Requests video frame binary data Yes
0xB4 GET_VIDEO Requests video frame frame
0xC0 SET_SIM Sets simulation options quality
0xC1 ACK Acknowledgement Yes
0xC3 SET_ORIEN Sets Okon’s orientation {pos, rot} Yes
0xC4 RST_SIM Resets simulation Yes
0xC5 PING Sends ping to server {timestamp, ping} {timestamp, ping} Yes
0xC6 GET_CPS Requests checkpoints state [{id,reached}, ...] Yes
0xC7 HIT_NGZ Transmits when Okon hits NGZ id Yes
0xC8 HIT_FZ Transmits when Okon hits FZ id Yes
0xC9 CHK_AP Checks actionpoint state id active Yes
0xCA ERROR Informs about server side error {info, jsonFromClient} Yes
0xDE GET_DETE Gets object detection [{visibleInFrame, min, max, fill, className, distance, colorPercentVisible}, ...] Yes
0xFF 0xFF Illegal packet. Breaks connection Yes

SET_MTR

Packet sets thrusters power and direction. FLH, FLV, BLV, BLH, FRH, FRV, BRV, BRH are abbreviations e.g. FLH FrontLeftHorizontal thruster ([H]orizontal, [V]ertical). Values are in range from -1.0f to 1.0f.
JSON structure:

  • FLH
  • FLV
  • BLV
  • BLH
  • FRH
  • FRV
  • BRV
  • BRH

Example request {"FLH":0.0,"FLV":0.0,"BLV":0.0,"BLH":0.0,"FRH":0.0,"FRV":0.0,"BRV":0.0,"BRH":0.0}

ARM_MTR

Packet arms motors. Without being armed, motors will not spin.

DISARM_MTR

Packet disarms motors. Without being armed, motors will not spin.

SET_CONTROL_MODE

Packet sets robots control mode:

  • stable - robot will keep set rotation
  • acro - robot will keep set rotation speed
  • manual - robot will not correct its rotation

SET_ACRO

Packet sets desired rotation speed and velocity in local coordinate system.
JSON structure:

  • rotSpeed
    • x
    • y
    • z
  • vel
    • x
    • y
    • z

Example request {"rotSpeed":{"x":0,"y":0,"z":0},"vel":{"x":0,"y":0,"z":0}}

SET_STABLE

Packet sets desired rotation and velocity in local coordinate system.
JSON structure:

  • rot
    • x
    • y
    • z
  • vel
    • x
    • y
    • z
  • depth

Example request {"rot":{"x":0,"y":0,"z":0},"vel":{"x":0,"y":0,"z":0},"depth":1.0}

SET_PID

Packet sets motors PIDs. WindupCapt limits max integral value. Limit limits max PID output from -limit to limit. Variables in each PID has the same structure.
JSON structure:

  • roll
    • p
    • i
    • d
    • windupCap
    • gain
    • limit
  • pitch
    • ...
  • yaw
    • ...
  • depth
    • ...
  • rollSpeed
    • ...
  • pitchSpeed
    • ...
  • yawSpeed
    • ...

Example request {"roll":{"p":0.4,"i":0,"d":0.03,"windupCap":1,"gain":1,"limit":0.5},"pitch":{"p":0.7,"i":0,"d":0.1,"windupCap":1,"gain":1,"limit":0.5},"yaw":{"p":0.3,"i":0,"d":0.04,"windupCap":1,"gain":1,"limit":0.5},"depth":{"p":10,"i":0,"d":4,"windupCap":1,"gain":1,"limit":0.5},"rollSpeed":{"p":0,"i":0,"d":0,"windupCap":0,"gain":0,"limit":0},"pitchSpeed":{"p":0,"i":0,"d":0,"windupCap":0,"gain":0,"limit":0},"yawSpeed":{"p":0,"i":0,"d":0,"windupCap":0,"gain":0,"limit":0}}

GET_SENS

Packet requests current values of on-board sensors (gyroscope, accelerometer and barometer). Values x, y, z for rot are in degrees.
JSON structure:

  • rot
    • x
    • y
    • z
  • rotSpeed
    • x
    • y
    • z
  • accel
    • x
    • y
    • z
  • rotAccel
    • x
    • y
    • z
  • baro
    • pressure

Example response {"rot":{"x":-9.81e-16,"y":180.0,"z":5.269e-7},"rotSpeed":{"x":1.2e-9,"y":1.41e-11,"z":2.282e-11},"accel":{"x":4.0e-16,"y":0.084,"z":-5.37e-17},"rotAccel":{"x":6.2e-11,"y":7.024e-13,"z":1.13e-12},"baro":{"pressure":11115.315}}

GET_DEPTH

Packet requests depth map.

Example response BASE64_DEPTH_IMAGE_STRING

GET_DEPTH_BYTES

Packet requests depth map.
binary data containing JPG/PNG encoded image

GET_VIDEO_BYTES

Packet requests video frame.
binary data containing JPG/PNG encoded image

GET_VIDEO

Packet requests video frame.

Example response BASE64_VIDEO_FRAME_STRING

SET_SIM

This packet allows to set the compression level of the frame. Value of the quality is in range from 0 to 100 (see settings file).
JSON structure

  • quality

ACK

Packet checks if the connection is still working. Server sends ACK each second of inactivity. If client send ACK server will respond with some dummy JSON.

SET_ORIEN

Packet allows to set position and rotation of the robot in simulation's world space. Rotation values are in degrees.
JSON structure:

  • rot
    • x
    • y
    • z
  • pos
    • x
    • y
    • z

Example request {"rot":{"x":0.0,"y":0.0,"z":0.0},"pos":{"x":1.0900000095367432,"y":-0.89980505108833314,"z":-2.7100000381469728}}

RST_SIM

Packet restart mission by randomizing Okons orientation and reseting all checkpoints. Packet is broadcasted to all connected clients.

PING

Packet allows to measure ping between client and simulation. Server sends back the exact copy of clients packet.

GET_CPS

Packet allows to retrive all checkpoints state. JSON structure:

  • Array
    • Object
      • id
      • reached
    • ...

Example response [{"id":"chk1","reached":true},{"id":"chk2","reached":false}]

HIT_NGZ

Packet send to all clients when Okon swims into No Go Zone.

Example response "NGZ1"

HIT_FZ

Packet send to all clients when Okon swims into Finish Zone. JSON structure:

  • id

Example response {"id":"FZ1"}

CHK_AP

Packet allows to checks if Okon is in a given actionpoint. If no data in request server will respond with ids of all action points. JSON structure:

  • active

Example request {"id":"AP1"}
Example response true

ERROR

Packet is send e.g. when client sends to server unknown packet.

JSON structure:

  • info
  • fromClient

Example response {"info":"Unknown dataframe type","fromClient":"someGarbageFromClient"}

GET_DETE

Packet requests detection info. Array of all objects in simulation is send. Each object info will have information if it is in frame and visible. Min and max variables define bounding box around the object. Fill tells how much space on the image the bounding box uses. JSON structure:

  • Array
    • Object
      • visibleInFrame
      • min
        • x
        • y
      • max
        • x
        • y
      • fill
      • className
      • distance
      • colorPercentVisible
    • ...

0xFF

If client sends this packet type, server will close the connection. Do not send this packet type.

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