Difference between revisions of "DevGuide/DesignOverview"

From PaparazziUAV
Jump to: navigation, search
m
 
Line 1: Line 1:
 
== Airborne Functional Diagram ==
 
== Airborne Functional Diagram ==
 +
[[Image:Airborne_software_functional.png]]
 +
 +
== Generating Doxygen Code Documentation ==
 +
 +
see [[Doxygen]]
 +
 +
== Previous designs ==
 +
 +
The documentation below this point reflects older version of paparazzi below v5.x
 +
 +
=== Airborne Functional Diagram ===
 
[[Image:functional_diagram.png]]
 
[[Image:functional_diagram.png]]
  
  
== Design Goals ==
+
=== Design Goals ===
 
  -Static approach
 
  -Static approach
 
  -Modularity
 
  -Modularity
Line 9: Line 20:
 
  -Runtime efficiency
 
  -Runtime efficiency
  
=== Static Approach ===
+
==== Static Approach ====
 
   -only "things that needs to be changed during flight are changeable
 
   -only "things that needs to be changed during flight are changeable
 
   -maximise compilation time resolutions
 
   -maximise compilation time resolutions
Line 18: Line 29:
 
     Safety/Robustness
 
     Safety/Robustness
  
=== Modularity ===
+
==== Modularity ====
  
 
[[Image:modularity.png]]
 
[[Image:modularity.png]]
Line 30: Line 41:
 
[[Image:dependancies_example.png]]
 
[[Image:dependancies_example.png]]
  
=== Hardware abstraction ===
+
==== Hardware abstraction ====
  
 
   -Segregate hardware dependant modules
 
   -Segregate hardware dependant modules
Line 37: Line 48:
  
  
=== Runtime Efficiency ===
+
==== Runtime Efficiency ====
  
 
We have to take care that our code runs efficient on the autopilot board microprocessor. It is for example very unlikely that we will physically change the serial port on which we connected our telemetry modem during a flight.
 
We have to take care that our code runs efficient on the autopilot board microprocessor. It is for example very unlikely that we will physically change the serial port on which we connected our telemetry modem during a flight.
Line 53: Line 64:
 
  UartWrite(...);
 
  UartWrite(...);
  
== Design Solutions ==
+
=== Design Solutions ===
  
 
  * Heavy pre-processor usage
 
  * Heavy pre-processor usage
Line 61: Line 72:
  
  
=== pre-processor ===
+
==== pre-processor ====
  
==== header selection ====
+
===== header selection =====
  
 
conf/airframes/funjet1.xml
 
conf/airframes/funjet1.xml
Line 83: Line 94:
  
 
   
 
   
==== macros ====
+
===== macros =====
  
 
conf/airframes/funjet1.xml
 
conf/airframes/funjet1.xml
Line 100: Line 111:
  
  
=== C code generation ===
+
==== C code generation ====
  
 
For problems too complex to solve with the pre processor, we use custom compilers to generate code from a description in xml
 
For problems too complex to solve with the pre processor, we use custom compilers to generate code from a description in xml
  
  
==== example 1 : command laws, aka mixers ====
+
===== example 1 : command laws, aka mixers =====
 
conf/airframes/funjet1.xml
 
conf/airframes/funjet1.xml
 
  <command_laws>
 
  <command_laws>
Line 128: Line 139:
  
  
==== example 2 : flight plan ====
+
===== example 2 : flight plan =====
  
 
conf/flight plans/example.xml
 
conf/flight plans/example.xml
Line 162: Line 173:
 
     }
 
     }
  
=== Makefile ===
+
==== Makefile ====
  
==== Connecting and configuring modules ====
+
===== Connecting and configuring modules =====
  
 
   ap.CFLAGS += -DDOWNLINK -DDOWNLINK_TRANSPORT=XBeeTransport -DXBEE_UART=Uart1
 
   ap.CFLAGS += -DDOWNLINK -DDOWNLINK_TRANSPORT=XBeeTransport -DXBEE_UART=Uart1
Line 172: Line 183:
  
  
==== Modules configuration ====
+
===== Modules configuration =====
  
 
3 sources of configuration:
 
3 sources of configuration:
Line 185: Line 196:
  
  
=== Conventions ===
+
==== Conventions ====
  
== Generating Doxygen Code Documentation ==
 
 
see [[Doxygen]]
 
  
 
[[Category:Software]] [[Category:Hardware]] [[Category:Developer_Documentation]]
 
[[Category:Software]] [[Category:Hardware]] [[Category:Developer_Documentation]]

Latest revision as of 15:21, 18 April 2015

Airborne Functional Diagram

Airborne software functional.png

Generating Doxygen Code Documentation

see Doxygen

Previous designs

The documentation below this point reflects older version of paparazzi below v5.x

Airborne Functional Diagram

Functional diagram.png


Design Goals

-Static approach
-Modularity
-Hardware abstraction
-Runtime efficiency

Static Approach

 -only "things that needs to be changed during flight are changeable
 -maximise compilation time resolutions
 advantages
   Error checking
   Efficiency
   Safety/Robustness

Modularity

Modularity.png

 -Separation of concerns
 -Maintenability
 -Interface
 -C provide no dedicated mechanism for modularity
 -Main issues with modularity are configuration and dependancies

Dependancies example.png

Hardware abstraction

 -Segregate hardware dependant modules

Hardware abstraction.png


Runtime Efficiency

We have to take care that our code runs efficient on the autopilot board microprocessor. It is for example very unlikely that we will physically change the serial port on which we connected our telemetry modem during a flight.

bad coding practice

switch(UART) {
 case UART0 : UARTO_write(...); break;
 case UART1 : UART1_write(...); break;
}

good coding practice

#define UartWrite(x) UART ## _write(x)
UartWrite(...);

Design Solutions

* Heavy pre-processor usage
* C code generation
* Heavy Makefile usage
* Conventions to define our own module layer


pre-processor

header selection

conf/airframes/funjet1.xml

<makefile>
ap.CFLAGS += -DACTUATORS=\"servos_4017_hw.h\"
</makefile>

generated var/FJ1/Makefile.ac

ap.CFLAGS += -DACTUATORS=\"servos_4017_hw.h\"

sw/airborne/actuators.h

#include ACTUATORS

expanded by pre-processor to

#include "servos_4017_hw.h"


macros

conf/airframes/funjet1.xml

 ap.CFLAGS += -DXBEE_UART=Uart1

sw/airborne/xbee.h

 #define __XBeeLink(dev, _x) dev##_x
 #define _XBeeLink(dev, _x) __XBeeLink(dev, _x)
 #define XBeeLink(_x) _XBeeLink(XBEE_UART, _x)
 #define XBeeBuffer() XBeeLink(ChAvailable())

expanded by pre-processor to

Uart1ChAvailable()


C code generation

For problems too complex to solve with the pre processor, we use custom compilers to generate code from a description in xml


example 1 : command laws, aka mixers

conf/airframes/funjet1.xml

<command_laws>
 <let var="aileron" value="@ROLL * AILEVON_AILERON_RATE"/>
 <let var="elevator" value="@PITCH * AILEVON_ELEVATOR_RATE"/>
 <set servo="AILEVON_LEFT" value="$elevator + $aileron"/>
 <set servo="AILEVON_RIGHT" value="$elevator - $aileron"/>
</command_laws>

generated var/FJ1/airframe.h

#define SetActuatorsFromCommands(values) { \
  uint16_t servo_value;\
  float command_value;\
  int16_t _var_aileron = values[COMMAND_ROLL] * AILEVON_AILERON_RATE;\
  int16_t _var_elevator = values[COMMAND_PITCH] * AILEVON_ELEVATOR_RATE;\
[....]
  command_value = _var_elevator + _var_aileron;\
  command_value *= command_value>0 ? SERVO_AILEVON_LEFT_TRAVEL_UP :   SERVO_AILEVON_LEFT_TRAVEL_DOWN;\
  servo_value = SERVO_AILEVON_LEFT_NEUTRAL + (int16_t)(command_value);\
  actuators[SERVO_AILEVON_LEFT] = ChopServo(servo_value, SERVO_AILEVON_LEFT_MIN, SERVO_AILEVON_LEFT_MAX);\
  Actuator(SERVO_AILEVON_LEFT) = SERVOS_TICS_OF_USEC(actuators[SERVO_AILEVON_LEFT]);\


example 2 : flight plan

conf/flight plans/example.xml

  <block name="For loop (circles wp 1)">
     <for from="0" to="3" var="i">
       <circle radius="DEFAULT_CIRCLE_RADIUS+ $i*10" wp="1" until="NavCircleCount() > 1"/>
     </for>
     <deroute block="Standby"/>
   </block>

generated var/flight plan.h

 Block(29) // For loop (circles wp 1)
   switch(nav_stage) {
     static int8_t _var_i;
     static int8_t _var_i_to;
     Stage(0)
       _var_i = 0 - 1;
       _var_i_to = 3;
     Label(for_11)
     Stage(1)
       if (++_var_i > _var_i_to) Goto(endfor_12) else NextStageAndBreak();
     Stage(2)
       NavVerticalAutoThrottleMode(RadOfDeg(0.000000));
       NavVerticalAltitudeMode(WaypointAlt(3), 0.);
       NavCircleWaypoint(3, (DEFAULT_CIRCLE_RADIUS+(_var_i*10)));
       if ((NavCircleCount()>1)) NextStageAndBreak();
       break;
     Stage(3)
       Goto(for_11)
     Label(endfor_12)
     Stage(5)
       NextBlock();
       break;
   }

Makefile

Connecting and configuring modules
 ap.CFLAGS += -DDOWNLINK -DDOWNLINK_TRANSPORT=XBeeTransport -DXBEE_UART=Uart1
 ap.srcs += downlink.c xbee.c
 ap.CFLAGS += -DUSE_UART1 -DUART1_BAUD=B9600
 ap.srcs += \$(SRC_ARCH)/uart_hw.c


Modules configuration

3 sources of configuration:

 * airframe configuration file ( airframe.xml ) which "compiled" to C files and Makefile
 * specific per module configuration file ( eg radio.xml, flightplan.xml) compiled to C code to allow factorization between airframes.
 * specific per board configuration file ( eg tiny.h ) to describe modules configuration imposed by board routing



Modules configuration.png


Conventions