SIL

Software-in-the-loop simulator for rockets

Compiling SIL

SIL works on Mac or Linux. Windows is not currently supported, but you can run it in the Vagrant VM. A C++ compiler (clang++ or g++) and Python (any version) are required. PM Leo or Jaren if compilation fails.

Run make and pass in microcontroller code:

make code0=../firmware-launch/fc/fc.h code1=../firmware-launch/tpc/tpc.h

Required microcontroller code file format

#include"pins.h"#include"mbed.h"#include"BMP388.h"// TODO Define your pins here// Syntax: DigitalOut <pin_name>(<pin_number>); (without the angle brackets)floatmax_alt;
// TODO What other vars might it be useful to define? I2Ci2c_sensors(I2C_SENSOR_SDA, I2C_SENSOR_SCL);
Serialdebug(DEBUG_TX, DEBUG_RX);
Pressurepressure;
BMP388barometer(&i2c_sensors, &debug);
voidstart() {
//Assign any other variables here. max_alt=0;
barometer.init();
}
voidloop() {
// Read pressure using the BMP388 librarybarometer.readPressure(&pressure);
floatpressure_pascals=pressure.pressure();
// TODO Convert pressure to altitude.// TODO Update max altitude // TODO Deploy parachutes at the correct time by setting pins to a boolean true value
}
intmain() {
start();
while (true) {
loop();
}
}

Code should be self-contained. Any includes except for flatbuffers and mbed will have to be copied to the SIL includes directory.

Running SIL

• To run a simulation file

./build/sil config/simulations/intro_proj_sim.json

• To connect to the debug serial ports, add -sN (unconnected serial ports will print to main output):

./build/sil config/simulations/intro_proj_sim.json -s01

• Then in separate terminal windows, open the serial client for each microcontroller:

./build/terminal 0
./build/terminal 1

Simulation file formats

Don't actually use // comments, they're not allowed in json 😊

Simulation file format

{"rocket": "config/rockets/testrocket.json",// Rocket file"wind": {// Simualted wind in environment"type": "fixed",// Only type for now"x": 1,// Wind dir vector"y": 0,"z": 0},"ground_height": 10,// Ground height at start"ground_height_far": 20,// Ground height when rocket moves away from start pos"timeout": 3,// When to end the sim after no movement"output": [// List of output types{"type": "pos",// Output type (see list of classes subclassing Output)"file": "pos_data.csv",// Output filename"frequency": 10000// Polling frequency}],"tests": [// List of tests to run, with various failures and required assertions (separate environment for each){"name": "test1","assertions": [// List of assertions checked at launch finish"max_altitude > 300",// Assertion format: {number | environment_variable} [><=] {number | environment_variable}"landing_speed < 10"],"failures": [// List of failures"altimeter"// Failure name (see failure classes for details)]}]}

Rocket file format

[// Array of rocket stages{"name": "booster",// Stage name"weight": 5,// Rocket stage weight"drag_area": 0.02,// Rocket stage drag area"leds": {// List of LEDs on rocket stage"led1": {// LED Name"pin": "flight_computer:7"// Connected PIN for LED}},"motors": {// List of motors on rocket stage"booster": {// Motor name"file": "config/motors/aerotech_j800t.json",// Motor JSON config file"fuse": 10// Fuse time (when the rocket will be activated after the sim start)}},"separators": {// List of stage separators"stage1": {// Name"separate": "sustainer",// Stage to separate (doesn't exist in this example)"pin": "flight_computer:10"// Connected pin}},"chutes": {// List of chutes"drogue": {// Name"drag_area": 5,// Chute drag area"pin": "flight_computer:12"// Connected pin}},"microcontrollers": {// List of MCUs"flight_computer": {// Name"id": 0,// ID --> should be unique to file"pin": "telemetry_power_control:24"// Powering pin (optional, if not present the mcu will always be on)},"telemetry_power_control": {"id": 1}},"communications": [// List of UART connections["flight_computer:4","telemetry_power_control:3"],["telemetry_power_control:4","flight_computer:3"],["SIL_INPUT","flight_computer:5"],// SIL_INPUT for simulated debug connection (in)["flight_computer:6","SIL_OUTPUT"],["SIL_INPUT","telemetry_power_control:5"],// SIL_OUTPUT for simulated debug connection (out)["telemetry_power_control:6","SIL_OUTPUT"]]}]

Motor file format

{"interpolation": "linear",// Type of interpolation between thrust curve points"thrust_curve": {// Time from activation and thrust (N), must start and end with 0, must be in chronological order"0": 0,"0.5": 100,"5": 100,"5.5": 0}}

Using debug uart

Use Serial or UARTSerial in mbed.h (in src/includes)

An example of output:

Serialdebug_uart(DEBUG_TX, DEBUG_RX, 115200); // tx pin, rx pin, baud rate (rate of data transfer)// printf is normal c printfdebug_uart.printf("Helloaltitudeis %f\n", altitude); // here altitude is a float

Adding output formats

• Create a .cc and .h file for the intended output (subclass of Output)
• Add relevant parsing code for the output in output_parser.cc and .h

Weird things are happening (segfault, etc.) when running or compiling the program

• Try make clean first