37 lines
2.3 KiB
Markdown
37 lines
2.3 KiB
Markdown
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This is a tool to allow MATLAB to interface with the SITL JSON backend.
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The SITL_connector function can be used to simplify the connection process. SITL_connector.m uses the TCP/UDP/IP Toolbox 2.0.6 by Peter Rydesäter and is much (10x) faster than the MATLAB functions available with the instrument control toolbox (and free!). However this may require compilation of a mex file, prebuilt mex files are included in most cases they will work without the need to re-compile.
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see Copter/SIM_multicopter.m for example usage.
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The function is defined as:
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```
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SITL_connector(target_ip,state,init_function,physics_function,delta_t)
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```
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- target_ip: the IP address of the machine running SITL eg '127.0.0.1'
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- state: this is the persistent physics state of the vehicle its is a structure and must contain the following felids:
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```
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state.gyro(roll, pitch, yaw) (radians/sec) body frame
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state.attitude(roll, pitch yaw) (radians)
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state.accel(north, east, down) (m/s^2) body frame
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state.velocity(north, east,down) (m/s) earth frame
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state.position(north, east, down) (m) earth frame
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```
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the structure can have also any other felids required for the physics model
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- init_function: function handle that will be called to init the physics model, this will be called on the first run and after a SITL reboot. It should take and return the state.
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function state init(state)
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init_function = @(state)init(state);
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- physics_function: function handle that will be called to update the physics model by a single time step. It should take in the state and array of 16 PWM inputs and return the state.
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```
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function state = physics_step(pwm_in,state)
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physics_function = @(pwm_in,state)physics_step(pwm_in,state);
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```
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- delta_t: time step size the physics model wil use in seconds. Note that this is directly connected to the maximum speed you can run SITL at.
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The JSON SITL interface is lock-step scheduled. This allows matlab breakpoints to work as normal.
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Using the connection it should be possible to achieve > 1500 fps, at this speed MATLAB code efficiency plays a important factor in the max frame rate. For a 400hz physics time step this gives a maximum speedup of 4 to 5 times. For planes and rovers it should be possible to use a much larger physics time step resulting in a larger maximum speed up. Note that large speedups risk the GCS getting left behind.
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