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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/MuShibo/Micro-Wheeled_leg-Robot/llms.txt

Use this file to discover all available pages before exploring further.

The Micro Wheeled-Leg Robot hosts a complete browser-based remote-control interface served directly from ESP32 flash memory — no app download or internet connection required. Once you join the robot’s access point and navigate to its IP address, a WebSocket connection is established between your browser and the on-board WebSocket server running on port 81. Every joystick movement, height adjustment, and button press sends a small JSON message over that socket, which the firmware parses in real time through the RobotProtocol::parseBasic() handler.

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Connecting to the Robot’s WiFi

The robot starts in Access Point (AP) mode by default.

Network Credentials

SSID: WLROBOT
Password: 12345678
Robot IP: 192.168.1.11

Recommended Browsers

Chrome or Firefox on Android, iOS, Windows, macOS, or Linux.
The interface uses standard WebSocket APIs — no plugins required.
Connection steps:
  1. On your device, open WiFi settings and select WLROBOT.
  2. Enter the password 12345678 and wait for the connection to establish.
  3. Open Chrome or Firefox and go to http://192.168.1.11.
  4. The robot’s control page loads from ESP32 flash. The page opens a WebSocket connection to ws://192.168.1.11:81 automatically.
The web interface is served by a WebServer instance on port 80. All control traffic flows through a separate WebSocketsServer instance on port 81. Both run concurrently on the ESP32 and are polled every loop iteration by web_loop().

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Control Interface Overview

Once the page loads and you have pressed “Robot go!” (see Startup), the following controls are available:
ControlWebSocket fieldDescription
Robot go! buttonstable = 1 / 0Enables or disables the balance controllers. Press while holding the robot upright — wheels touching the ground.
Joystick X axisjoy_x (integer)Yaw / turning left and right. Positive values rotate clockwise.
Joystick Y axisjoy_y (integer)Forward and backward movement. Passed through lpf_joyy (Tf = 0.2) before reaching the speed controller.
Height sliderheight (32 – 80)Leg extension level. 32 = maximum squat, 80 = fully extended, default = 38.
Jumpdir = “jump” → “stop”Triggers the jump sequence — see below.
Directional buttonsdir = “forward” / “back” / “left” / “right” / “stop”Discrete movement commands (supplementary to joystick).

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Leg Height and Servo Positions

The height value maps linearly to servo positions using the formulas defined in leg_loop(): 
Position[0] (ID 1, left)  = 2048 + 12 + 8.4 × (height − 32)
Position[1] (ID 2, right) = 2048 − 12 − 8.4 × (height − 32)
The firmware clamps the output to safe mechanical limits:
ServoMinimum positionMaximum position
ID 1 (left)21102510
ID 2 (right)15861986
At the default height = 38 the servos sit near the low end of travel, keeping the centre of mass low for stability. Increasing height raises the body and shifts the balance dynamics — the firmware compensates automatically via the adaptive speed gain.

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Jump Maneuver

The jump is a timed open-loop leg sequence triggered by sending dir = "jump" followed by dir = "stop". The firmware detects the transition (dir_last == JUMP and dir == STOP) and executes jump_loop():
1

Full extension

Both servos are commanded to the maximum extension equivalent to height = 80 at maximum speed and zero acceleration limiting. This is the “push-off” phase that launches the chassis upward.
Position[0] = 2048 + 12 + 8.4 × (80 − 32) = 2463
Position[1] = 2048 − 12 − 8.4 × (80 − 32) = 1633
2

Retraction (~30 loop cycles later)

After jump_flag reaches 30 (approximately 30 ms at loop speed), the legs retract to mid height (height = 40 equivalent) to prepare for landing.
Position[0] = 2048 + 12 + 8.4 × (40 − 32) = 2127
Position[1] = 2048 − 12 − 8.4 × (40 − 32) = 1969
3

Recovery hold (~200 loop cycles)

jump_flag continues incrementing. While it is non-zero, the balance controller detects “wheels off ground” and disables the wheel-position terms to prevent erratic wheel spin on landing. Normal operation resumes once jump_flag exceeds 200 and resets to 0.

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WebSocket JSON Format

Every control update from the browser is a JSON object. The firmware’s webSocketEventCallback deserialises it with ArduinoJson and routes it to rp.parseBasic(). A representative message looks like this: 
{
  "mode": "basic",
  "dir": "forward",
  "height": 38,
  "roll": 0,
  "linear": 0,
  "angular": 0,
  "stable": 1,
  "joy_x": 0,
  "joy_y": 50
}
FieldTypeValid valuesNotes
modestring"basic"Selects the parseBasic() handler
dirstring"forward", "back", "left", "right", "stop", "jump"Maps to QR_State_t enum (0–5)
heightinteger32 – 80Leg extension; default 38
rollintegernegative/positiveRoll compensation offset
linearintegernegative/positiveForward speed bias
angularintegernegative/positiveAngular speed bias
stableinteger0 or 1Enables (1) or disables (0) balance output
joy_xintegernegative/positiveYaw axis; fed into yaw_loop()
joy_yintegernegative/positiveSpeed axis; filtered by lpf_joyy

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STA Mode — Join an Existing Network

By default the robot creates its own hotspot. To connect it to a home or lab network instead, switch it to Station (STA) mode:
1

Edit wifi.cpp

Open 3.Software/wl_pro_robot/wifi.cpp and update the STA credentials:
char *sta_ssid     = "YourNetworkName";
char *sta_password = "YourNetworkPassword";
2

Switch the WiFi init call

In wl_pro_robot.ino, comment out WiFi_SetAP() and uncomment set_sta_wifi() in setup():
// WiFi_SetAP();
set_sta_wifi();   // join existing network
3

Flash and find the IP

Compile and flash the firmware. After boot, open your router’s DHCP client list to find the IP address the robot was assigned. The Serial Monitor (115200 baud) also prints it:
IP Address: 192.168.x.x
Navigate to that address in your browser instead of 192.168.1.11.
In STA mode you can connect multiple devices to the robot simultaneously through your router, and the robot has internet access if needed for future firmware features. AP mode is simpler and requires no router.

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