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256 lines
12 KiB
Markdown
256 lines
12 KiB
Markdown
# Simulation-In-Hardware (SIH)
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<Badge type="tip" text="PX4 v1.9 (MC)" /><Badge type="tip" text="PX4 v1.13 (MC, VTOL, FW)" />
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:::warning
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This simulator is [community supported and maintained](../simulation/community_supported_simulators.md).
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It may or may not work with current versions of PX4 (known to work in PX4 v1.14).
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See [Toolchain Installation](../dev_setup/dev_env.md) for information about the environments and tools supported by the core development team.
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:::
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Simulation-In-Hardware (SIH) is an alternative to [Hardware In The Loop simulation (HITL)](../simulation/hitl.md) for quadrotors, fixed-wing vehicles (airplane), and VTOL tailsitters.
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SIH can be used by new PX4 users to get familiar with PX4 and the different modes and features, and of course to learn to fly a vehicle using an RC controller in simulation, which is not possible using SITL.
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## 개요
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With SIH the whole simulation is running on embedded hardware: the controller, the state estimator, and the simulator.
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The Desktop computer is only used to display the virtual vehicle.
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### 호환성
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- SIH is compatible with all PX4 supported boards except those based on FMUv2.
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- SIH for quadrotor is supported from PX4 v1.9.
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- SIH for fixed-wing (airplane) and VTOL tailsitter are supported from PX4 v1.13.
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- SIH as SITL (without hardware) from PX4 v1.14.
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- SIH for Standard VTOL from PX4 v1.16.
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### Benefits
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SIH provides several benefits over HITL:
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- It ensures synchronous timing by avoiding the bidirectional connection to the computer.
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As a result the user does not need such a powerful desktop computer.
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- The whole simulation remains inside the PX4 environment.
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Developers who are familiar with PX4 can more easily incorporate their own mathematical model into the simulator.
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They can, for instance, modify the aerodynamic model, or noise level of the sensors, or even add a sensor to be simulated.
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- The physical parameters representing the vehicle (such as mass, inertia, and maximum thrust force) can easily be modified from the [SIH parameters](../advanced_config/parameter_reference.md#simulation-in-hardware).
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## Requirements
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To run the SIH, you will need a:
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- [Flight controller](../flight_controller/index.md), such as a Pixhawk-series board
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- [Manual controller](../getting_started/px4_basic_concepts.md#manual-control): either a [radio control system](../getting_started/rc_transmitter_receiver.md) or a [joystick](../config/joystick.md).
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- QGroundControl for flying the vehicle via GCS.
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- Development computer for visualizing the virtual vehicle (optional).
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From PX4 v1.14 you can run SIH "as SITL", in which case a flight controller is not required.
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## Starting SIH
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To set up/start SIH:
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1. Connect the flight controller to the desktop computer with a USB cable.
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2. Open QGroundControl and wait for the flight controller too boot and connect.
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3. Open [Vehicle Setup > Airframe](../config/airframe.md) then select the desired frame:
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- [SIH Quadcopter X](../airframes/airframe_reference.md#copter_simulation_sih_quadcopter_x)
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- [SIH plane AERT](../airframes/airframe_reference.md#plane_simulation_sih_plane_aert)
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- [SIH Tailsitter Duo](../airframes/airframe_reference.md#vtol_simulation_sih_tailsitter_duo)
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- [SIH Standard VTOL QuadPlane](../airframes/airframe_reference.md#vtol_simulation_sih_standard_vtol_quadplane)
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The autopilot will then reboot.
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The `sih` module is started on reboot, and the vehicle should be displayed on the ground control station map.
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:::warning
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The airplane needs to takeoff in manual mode at full throttle.
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Also, if the airplane crashes the state estimator might lose its fix.
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:::
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## Display/Visualisation (optional)
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The SIH-simulated vehicle can be displayed using [jMAVSim](../sim_jmavsim/index.md) as a visualiser.
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:::tip
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SIH does not _need_ a visualiser — you can connect with QGroundControl and fly the vehicle without one.
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:::
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To display the simulated vehicle:
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1. Close _QGroundControl_ (if open).
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2. Unplug and replug the flight controller (allow a few seconds for it to boot).
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3. Start jMAVSim by calling the script **jmavsim_run.sh** from a terminal:
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```sh
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./Tools/simulation/jmavsim/jmavsim_run.sh -q -d /dev/ttyACM0 -b 2000000 -o
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```
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where the flags are:
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- `-q` to allow the communication to _QGroundControl_ (optional).
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- `-d` to start the serial device `/dev/ttyACM0` on Linux.
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On macOS this would be `/dev/tty.usbmodem1`.
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- `-b` to set the serial baud rate to `2000000`.
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- `-o` to start jMAVSim in _display Only_ mode (i.e. the physical engine is turned off and jMAVSim only displays the trajectory given by the SIH in real-time).
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- add a flag `-a` to display an aircraft or `-t` to display a tailsitter.
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If this flag is not present a quadrotor will be displayed by default.
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4. After few seconds, _QGroundControl_ can be opened again.
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At this point, the system can be armed and flown.
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The vehicle can be observed moving in jMAVSim, and on the QGC _Fly_ view.
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## SIH as SITL (no FC)
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SIH can be run as SITL (Software-In-The-Loop) from v1.14.
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What this means is that the simulation code is executed on the laptop/computer instead of a flight controller, similar to Gazebo or jMAVSim.
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In this case you don't need the flight controller hardware.
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To run SIH as SITL:
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1. Install the [PX4 Development toolchain](../dev_setup/dev_env.md).
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2. Run the appropriate make command for each vehicle type (at the root of the PX4-Autopilot repository):
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- quadrotor:
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```sh
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make px4_sitl sihsim_quadx
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```
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- Fixed-wing (plane):
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```sh
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make px4_sitl sihsim_airplane
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```
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- XVert VTOL tailsitter:
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```sh
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make px4_sitl sihsim_xvert
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```
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- Standard VTOL:
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```sh
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make px4_sitl sihsim_standard_vtol
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```
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### Change Simulation Speed
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SITL allows the simulation to be run faster than real time.
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To run the airplane simulation 10 times faster than real time, run the command:
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```sh
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PX4_SIM_SPEED_FACTOR=10 make px4_sitl sihsim_airplane
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```
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To display the vehicle in jMAVSim during SITL mode, enter the following command in another terminal:
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```sh
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./Tools/simulation/jmavsim/jmavsim_run.sh -p 19410 -u -q -o
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```
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- add a flag `-a` to display an aircraft or `-t` to display a tailsitter.
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If this flag is not present a quadrotor will be displayed by default.
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### Set Custom Takeoff Location
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The takeoff location in SIH on SITL can be set using environment variables.
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This will override the default takeoff location.
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The variables to set are: `PX4_HOME_LAT`, `PX4_HOME_LON`, and `PX4_HOME_ALT`.
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예:
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```sh
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export PX4_HOME_LAT=28.452386
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export PX4_HOME_LON=-13.867138
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export PX4_HOME_ALT=28.5
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make px4_sitl sihsim_quadx
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```
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## Adding New Airframes
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[Adding a new airframe](../dev_airframes/adding_a_new_frame.md) for use in SIH simulation is much the same as for other use cases.
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You still need to configure your vehicle type and [geometry](../config/actuators.md) (`CA_` parameters) and start any other defaults for that specific vehicle.
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:::warning
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Not every vehicle can be simulated with SIH — there are currently [four supported vehicle types](../advanced_config/parameter_reference.md#SIH_VEHICLE_TYPE), each of which has a relatively rigid implementation in [`sih.cpp`](https://github.com/PX4/PX4-Autopilot/blob/main/src/modules/simulation/simulator_sih/sih.cpp).
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:::
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The specific differences for SIH simulation airframes are listed in the sections below.
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For all variants of SIH:
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- Set all the [Simulation In Hardware](../advanced_config/parameter_reference.md#simulation-in-hardware) parameters (prefixed with `SIH_`) in order to configure the physical model of the vehicle.
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::: tip
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Make sure that the `SIH_*` parameters and the `CA_*` parameters describe the same vehicle.
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Note that some of these parameters are redundant!
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:::
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- `param set-default SYS_HITL 2` to enable SIH on the next boot.
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::: info
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This also disables input from real sensors.
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For SIH on the FC (only), it also enables the simulated GPS, barometer, magnetometer, and airspeed sensor.
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For SIH on SITL you will need to explicitly enable these sensors as shown below.
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:::
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- `param set-default EKF2_GPS_DELAY 0` to improve state estimator performance (the assumption of instant GPS measurements would normally be unrealistic, but is accurate for SIH).
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For SIH on FC:
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- Airframe file goes in `ROMFS/px4fmu_common/init.d/airframes` and follows the naming template `${ID}_${model_name}.hil`, where `ID` is the `SYS_AUTOSTART_ID` used to select the airframe, and `model_name` is the airframe model name.
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- Add the model name in `ROMFS/px4fmu_common/init.d/airframes/CMakeLists.txt` to generate a corresponding make target.
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- Actuators are configured with `HIL_ACT_FUNC*` parameters (not the usual `PWM_MAIN_FUNC*` parameters).
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This is to avoid using the real actuator outputs in SIH.
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Similarly, the bitfield for inverting individual actuator output ranges is `HIL_ACT_REV`, rather than `PWM_MAIN_REV`.
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For SIH as SITL (no FC):
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- Airframe file goes in `ROMFS/px4fmu_common/init.d-posix/airframes` and follows the naming template `${ID}_sihsim_${model_name}`, where `ID` is the `SYS_AUTOSTART_ID` used to select the airframe, and `model_name` is the airframe model name.
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- Add the model name in `src/modules/simulation/simulator_sih/CMakeLists.txt` to generate a corresponding make target.
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- Actuators are configured as usual with `PWM_MAIN_FUNC*` and `PWM_MAIN_REV`.
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- Additionally, set:
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- `PX4_SIMULATOR=${PX4_SIMULATOR:=sihsim}`
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- `PX4_SIM_MODEL=${PX4_SIM_MODEL:=svtol}` (replacing `svtol` with the airframe model name)
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- Enable the simulated sensors using [SENS_EN_GPSSIM](../advanced_config/parameter_reference.md#SENS_EN_GPSSIM), [SENS_EN_BAROSIM](../advanced_config/parameter_reference.md#SENS_EN_BAROSIM), [SENS_EN_MAGSIM](../advanced_config/parameter_reference.md#SENS_EN_MAGSIM), and [SENS_EN_ARSPDSIM](../advanced_config/parameter_reference.md#SENS_EN_ARSPDSIM) (this is only needed for SIH-as-SITL):
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- `param set-default SENS_EN_GPSSIM 1`
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- `param set-default SENS_EN_BAROSIM 1`
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- `param set-default SENS_EN_MAGSIM 1`
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- `param set-default SENS_EN_ARSPDSIM 1` (if it is a fixed-wing or VTOL airframe with airspeed sensor)
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For specific examples see the `_sihsim_` airframes in [ROMFS/px4fmu_common/init.d-posix/airframes](https://github.com/PX4/PX4-Autopilot/blob/main/ROMFS/px4fmu_common/init.d-posix/airframes/) (SIH as SITL) and [ROMFS/px4fmu_common/init.d/airframes](https://github.com/PX4/PX4-Autopilot/tree/main/ROMFS/px4fmu_common/init.d/airframes) (SIH on FC).
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## Dynamic Models
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The dynamic models for the various vehicles are:
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- Quadrotor: [pdf report](https://github.com/PX4/PX4-user_guide/raw/main/assets/simulation/SIH_dynamic_model.pdf).
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- Fixed-wing: Inspired by the PhD thesis: "Dynamics modeling of agile fixed-wing unmanned aerial vehicles." Khan, Waqas, supervised by Nahon, Meyer, McGill University, PhD thesis, 2016.
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- Tailsitter: Inspired by the master's thesis: "Modeling and control of a flying wing tailsitter unmanned aerial vehicle." Chiappinelli, Romain, supervised by Nahon, Meyer, McGill University, Masters thesis, 2018.
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## 비디오
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<lite-youtube videoid="PzIpSCRD8Jo" title="SIH FW demo"/>
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## Credits
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SIH was originally developed by Coriolis g Corporation.
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The airplane model and tailsitter models were added by Altitude R&D inc.
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Both are Canadian companies:
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- Coriolis g developped a new type of Vertical Takeoff and Landing (VTOL) vehicles based on passive coupling systems;
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- [Altitude R&D](https://www.altitude-rd.com/) is specialized in dynamics, control, and real-time simulation (today relocated in Zurich).
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The simulator is released for free under BSD license.
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