The Earth Rover Mini Plus is a mobile robot platform controlled through the cloud-based Frodobots SDK. Unlike traditional robots with direct hardware connections, it uses HTTP API communication for control and WebRTC for camera streaming.
Overview Earth Rover Mini Plus offers:
Cloud-based control via Frodobots SDK
Dual camera system (front and rear)
Linear and angular velocity control
Telemetry including GPS, battery, and orientation
HTTP API communication
No direct hardware connection required
Features
Mobility : Differential drive with linear and angular velocity controlCameras : Front and rear cameras via WebRTC/Agora cloudTelemetry : Battery, GPS, orientation, vibration sensorsControl : HTTP POST requests to SDK serverDeployment : Cloud-connected operation
Architecture The Earth Rover Mini Plus uses a unique cloud-based architecture:
Your Code (LeRobot) ↓ HTTP API Frodobots SDK Server (localhost:8000 or remote) ↓ Cloud (WebRTC/HTTP) Earth Rover Mini Plus Robot
Installation Prerequisites
Frodobots SDK must be running (provided by manufacturer)
Robot must be connected to Frodobots cloud
Network access to SDK server
Software Installation No additional drivers or hardware connections required.
Configuration Basic Configuration from lerobot.robots.earthrover_mini_plus import ( EarthRoverMiniPlus, EarthRoverMiniPlusConfig ) config = EarthRoverMiniPlusConfig( robot_type = "earthrover_mini_plus" , id = "rover_1" , sdk_url = "http://localhost:8000" # Frodobots SDK URL )
Remote SDK Configuration config = EarthRoverMiniPlusConfig( robot_type = "earthrover_mini_plus" , id = "rover_remote" , sdk_url = "http://192.168.1.100:8000" # Remote SDK server )
Configuration Parameters sdk_url
str
default: "http://localhost:8000"
URL of the Frodobots SDK server. Use localhost if SDK runs on same machine, or remote IP if SDK runs elsewhere.
Robot identifier (for calibration file compatibility, though not used for this robot)
Usage Basic Connection from lerobot.robots.earthrover_mini_plus import ( EarthRoverMiniPlus, EarthRoverMiniPlusConfig ) config = EarthRoverMiniPlusConfig( robot_type = "earthrover_mini_plus" , id = "rover_1" , sdk_url = "http://localhost:8000" ) with EarthRoverMiniPlus(config) as robot: # Get current state obs = robot.get_observation() print ( f "Battery: { obs[ 'battery.level' ] } %" ) print ( f "GPS: { obs[ 'gps.latitude' ] } , { obs[ 'gps.longitude' ] } " ) # Send movement command action = { "linear.vel" : 0.5 , # m/s forward "angular.vel" : 0.0 # rad/s (no rotation) } robot.send_action(action)
The robot returns comprehensive telemetry:
obs = robot.get_observation() # Returns: { # Camera images "front" : np.ndarray, # Front camera (height, width, 3) "rear" : np.ndarray, # Rear camera (height, width, 3) # Motion "linear.vel" : 0.5 , # Current linear velocity (m/s) # Power "battery.level" : 85.0 , # Battery percentage (0-100) # Orientation "orientation.deg" : 45.0 , # Compass heading (degrees) # GPS "gps.latitude" : 37.7749 , # Latitude "gps.longitude" : - 122.4194 , # Longitude "gps.signal" : 4 , # GPS signal strength # Status "signal.level" : 3 , # Network signal strength "vibration" : 0.1 , # Vibration level "lamp.state" : False # Lamp on/off }
action = { "linear.vel" : 0.5 , # Linear velocity (m/s) # Positive = forward, negative = backward "angular.vel" : 0.3 # Angular velocity (rad/s) # Positive = CCW, negative = CW } robot.send_action(action)
Camera Access Cameras are accessed via SDK HTTP endpoints:
with EarthRoverMiniPlus(config) as robot: obs = robot.get_observation() # Front camera image front_img = obs[ "front" ] print ( f "Front camera shape: { front_img.shape } " ) # Rear camera image rear_img = obs[ "rear" ] print ( f "Rear camera shape: { rear_img.shape } " ) # Images are RGB numpy arrays import cv2 cv2.imwrite( "front_view.jpg" , cv2.cvtColor(front_img, cv2. COLOR_RGB2BGR ))
Camera frames are streamed via WebRTC through Agora cloud and accessed via SDK HTTP endpoints, not through direct Camera objects.
Telemetry obs = robot.get_observation() latitude = obs[ "gps.latitude" ] longitude = obs[ "gps.longitude" ] signal = obs[ "gps.signal" ] # Signal strength print ( f "Position: { latitude } , { longitude } " ) print ( f "GPS Signal: { signal } /5" )
Battery Monitoring obs = robot.get_observation() battery = obs[ "battery.level" ] # 0-100% if battery < 20 : print ( "Low battery warning!" ) # Return to base or stop
Orientation obs = robot.get_observation() heading = obs[ "orientation.deg" ] # 0-360 degrees print ( f "Robot heading: { heading } °" )
Movement Control Straight Line Motion # Move forward robot.send_action({ "linear.vel" : 0.5 , # 0.5 m/s forward "angular.vel" : 0.0 }) # Move backward robot.send_action({ "linear.vel" : - 0.3 , # 0.3 m/s backward "angular.vel" : 0.0 })
Rotation # Rotate in place (CCW) robot.send_action({ "linear.vel" : 0.0 , "angular.vel" : 0.5 # rad/s }) # Rotate in place (CW) robot.send_action({ "linear.vel" : 0.0 , "angular.vel" : - 0.5 })
Curved Motion # Drive in a curve robot.send_action({ "linear.vel" : 0.4 , # Forward "angular.vel" : 0.2 # While turning })
Stop # Emergency stop robot.send_action({ "linear.vel" : 0.0 , "angular.vel" : 0.0 })
No Calibration Required Unlike motor-based robots, the Earth Rover Mini Plus does not require calibration:
# is_calibrated always returns True print (robot.is_calibrated) # True # calibrate() is a no-op robot.calibrate() # Does nothing
HTTP API Details The robot communicates with the SDK via HTTP:
# Internally, the robot makes requests to: # - GET {sdk_url}/robot/state - Get telemetry # - GET {sdk_url}/camera/front - Get front camera frame # - GET {sdk_url}/camera/rear - Get rear camera frame # - POST {sdk_url}/robot/command - Send motion commands
Requests are made using the requests library with:
Timeout: 5 seconds
Error handling: Cached fallback values
Automatic retry on failure
Error Handling The robot implements graceful degradation:
# If HTTP request fails: # - Uses cached values from previous successful request # - Logs warning # - Continues operation # Check if using cached data try : obs = robot.get_observation() except Exception as e: print ( f "Communication error: { e } " ) # Robot returns last known good observation
Troubleshooting SDK Not Running # Check if SDK is accessible curl http://localhost:8000/health # If not, start the Frodobots SDK # (Instructions from SDK documentation)
Connection Timeout # Verify SDK URL import requests response = requests.get( "http://localhost:8000/robot/state" , timeout = 5 ) print (response.status_code) # Should be 200
Camera Frames Not Updating # Check SDK camera endpoints import requests response = requests.get( "http://localhost:8000/camera/front" ) if response.status_code == 200 : print ( "Front camera OK" ) else : print ( f "Front camera error: { response.status_code } " )
Robot Not Moving # Check if action is being sent import requests response = requests.post( "http://localhost:8000/robot/command" , json = { "linear" : 0.5 , "angular" : 0.0 } ) print (response.json())
Network Issues
Ensure SDK server is running
Check firewall rules
Verify robot is connected to Frodobots cloud
Check network connectivity between your code and SDK
Implementation Details
Communication: HTTP REST API
Cameras: WebRTC/Agora cloud streaming via SDK
No direct hardware connection
No motor bus (uses HTTP commands)
Source: /home/daytona/workspace/source/src/lerobot/robots/earthrover_mini_plus/robot_earthrover_mini_plus.py
Config: /home/daytona/workspace/source/src/lerobot/robots/earthrover_mini_plus/config_earthrover_mini_plus.py
Robot Overview See all supported robots
LeKiwi Another mobile manipulator platform
Recording Data Record outdoor navigation data
Camera API Camera system overview
External Resources