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RflySim APIs - Low-Level Control Interface Library

The RflySim APIs library provides a complete set of low-level control interfaces, covering read/write operations for key data such as attitude, velocity, position, acceleration, force/torque, remote controller, and actuators, supporting user-defined controller development and real-machine deployment.

Module List

HIL Control Interfaces

Module Function Description
HIL16 Ctrls Norm HIL 16-dimensional normalized control interface, outputting normalized actuator control commands
HIL16 Ctrls PWM HIL 16-dimensional PWM control interface, outputting PWM-format actuator control signals

Remote Controller Interfaces

Module Function Description
Input RC Cali Remote controller input calibration module, supporting channel calibration and neutral point setting
Input RC Norm Normalized remote controller input, converting raw PWM signals to standardized values in the [-1, 1] range
RC Over Ctrl Remote controller override control, enabling RC signal priority over automatic controllers

Offboard Control Interfaces

Module Function Description
Offboard PVA Ctrl Offboard position/velocity/acceleration control, supporting multi-level control of position, velocity, and acceleration
Offboard Att Ctrl Offboard attitude control, supporting attitude angle and angular rate control
Offboard Adv Ctrl Offboard advanced control, supporting more complex control modes and hybrid control strategies
Off Ctrl Msg All Offboard control message aggregation, integrating command outputs from multiple control modes

State Acquisition Interfaces

Module Function Description
Pos Vel Att All Full-state acquisition of position/velocity/attitude, outputting the complete motion state of the vehicle
Msg2Simulink API Message-to-Simulink API, converting MAVLink messages into Simulink-compatible formats
Torque Thrust Ctrls Torque/thrust control interface, supporting low-level control based on torque and thrust

Utility Modules

Module Function Description
Re PX4 Block PX4 module reconfiguration, supporting dynamic reconfiguration of flight controller parameters and module settings

Usage Scenarios

Custom Controller Development

  • Position Controller: Develop custom position, velocity, and acceleration controllers using Offboard PVA Ctrl
  • Attitude Controller: Implement custom attitude stabilization and control using Offboard Att Ctrl
  • Force-Position Hybrid Control: Achieve low-level force/torque-based control by combining Torque Thrust Ctrls

Real-Machine Deployment

  • HIL Simulation Validation: Validate controllers in hardware-in-the-loop simulation using HIL16 Ctrls modules
  • Real-Machine Control: Directly control real vehicles using Simulink controllers via Offboard interfaces
  • Remote Controller Integration: Enable seamless switching between manual and automatic control using RC-related modules

Data Acquisition and Analysis

  • State Monitoring: Acquire the complete motion state of the vehicle using Pos Vel Att All
  • Message Parsing: Convert flight controller messages into usable data via Msg2Simulink API
  • Real-Time Analysis: Perform real-time analysis of flight controller data and generate control decisions in Simulink

Usage Notes

Offboard Control Notes

  1. Mode Switching: Ensure the flight controller is in the correct flight mode (typically Position or Hold mode) before entering Offboard mode
  2. Command Frequency: Offboard control commands must be sent at a sufficiently high frequency (≥50 Hz recommended); otherwise, the flight controller will exit Offboard mode
  3. Safety Boundaries: Always define reasonable flight boundaries and fault protection mechanisms when using Offboard control
  4. Coordinate System Convention: Ensure that command outputs from the Simulink controller align with the coordinate system expected by the flight controller (typically NED)

HIL Simulation Notes

  1. Signal Range: Control signals output by HIL16 Ctrls must conform to the flight controller’s expected normalized or PWM ranges
  2. Simulation Synchronization: Ensure the Simulink simulation step size matches the flight controller’s control period to avoid timing inconsistencies
  3. Sensor Models: In HIL simulation, sensor data used by the flight controller originates from the Simulink model; ensure sufficient accuracy of the sensor models

Remote Controller Integration Notes

  1. Channel Mapping: Ensure RC input channels match the channel functions configured on the flight controller (e.g., throttle, yaw, pitch, roll)
  2. Loss-of-Signal Protection: Configure appropriate flight controller protection behaviors (e.g., return-to-launch, landing, or hold) when RC signal is lost
  3. Mode Switching: Properly configure RC channels for flight mode switching to ensure smooth transitions between automatic and manual modes

Note: This document serves as the index for the RflySim APIs library. For detailed usage instructions for each module, please refer to its respective standalone documentation page.