Example Source Code

Code:

/*
ActivMedia Robotics Interface for Applications (ARIA)
Copyright (C) 2004,2005 ActivMedia Robotics, LLC


    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

If you wish to redistribute ARIA under different terms, contact
ActivMedia Robotics for information about a commercial version of ARIA at
robots@activmedia.com or
ActivMedia Robotics, 19 Columbia Drive, Amherst, NH 03031; 800-639-9481

*/

#include "Aria.h"

/*
This example demonstrates how to make actions and how to use them.

It creates two actions, Go and Turn. Go will drive the robot forward safely,
while Turn will avoid obstacles by turning. It also adds a predefined
action from Aria which tries to recover from stalls (hit something and
can't move forward) by backing and turning.

Each of these actions have the normal constructor and destructor, note that
the constructors use constructor chaining to create their ArAction part
correctly.  Each action then also implements the essential virtual method,
fire(). This fire function is called by the ArRobot's action resolver, and
returns values that, in combination with other actions' desired behavior,
determine the driving commands sent to the robot.

Also note that each of these actions override the setRobot function; these
implementations obtain the sonar device from the robot in addition to doing the
needed caching of the robot pointer.  This is what you should do if you
care about the presence or absence of a particular sensor.  If you don't
care about any particular sensor you could just use one of the
ArRobot::checkRangeDevice functions (there are four of them).
Also note that these are very naive actions, they are simply an example
of how to use actions.

See the Aria reference manual for more details about actions.

This program will only try to open a direct serial port connection
to the robot, it will not work in the simulator.
*/


/* This action drives the robot forward, but stops if obstacles are
 * detected by sonar.
 */
class ActionGo : public ArAction
{
public:
  // constructor, sets myMaxSpeed and myStopDistance
  ActionGo(double maxSpeed, double stopDistance);
  // destructor, its just empty, we don't need to do anything
  virtual ~ActionGo(void) {};
  // fire, this is what the resolver calls to figure out what this action wants
  virtual ArActionDesired *fire(ArActionDesired currentDesired);
  // sets the robot pointer, also gets the sonar device
  virtual void setRobot(ArRobot *robot);
protected:
  // this is to hold the sonar device form the robot
  ArRangeDevice *mySonar;

  // what the action wants to do. fire() modifies this and returns a pointer
  // to it.
  ArActionDesired myDesired;

  // maximum speed
  double myMaxSpeed;

  // stop if obstacles are closer than this distance.
  double myStopDistance;
};


/* This action turns the robot away from obstacles detected by the
 * robot's sonar. */
class ActionTurn : public ArAction
{
public:
  // constructor, sets the turnThreshold, and turnAmount
  ActionTurn(double turnThreshold, double turnAmount);
  // destructor, its just empty, we don't need to do anything
  virtual ~ActionTurn(void) {};
  // fire, this is what the resolver calls to figure out what this action wants
  virtual ArActionDesired *fire(ArActionDesired currentDesired);
  // sets the robot pointer, also gets the sonar device
  virtual void setRobot(ArRobot *robot);
protected:
  // this is to hold the sonar device form the robot
  ArRangeDevice *mySonar;
  // what the action wants to do
  ArActionDesired myDesired;
  // distance at which to start turning
  double myTurnThreshold;
  // amount to turn when turning is needed
  double myTurnAmount;
  // value ot hold onto so turns are smooth, which direction its turning
  int myTurning; // -1 == left, 1 == right, 0 == none
};

/*
  This is the constructor, note the use of constructor chaining with the
  ArAction. also note how it uses setNextArgument, which makes it so that
  other things can see what parameters this action has, and set them.
  It also initializes the classes variables.
*/
ActionGo::ActionGo(double maxSpeed, double stopDistance) :
  ArAction("Go")
{
  mySonar = NULL;
  myMaxSpeed = maxSpeed;
  myStopDistance = stopDistance;
  setNextArgument(ArArg("maximum speed", &myMaxSpeed, "Maximum speed to go."));
  setNextArgument(ArArg("stop distance", &myStopDistance, "Distance at which to stop."));
}
/*
  Sets the myRobot pointer (all setRobot overloaded functions must do this),
  finds the sonar device from the robot, and if the sonar isn't there,
  then it deactivates itself.
*/
void ActionGo::setRobot(ArRobot *robot)
{
  myRobot = robot;
  mySonar = myRobot->findRangeDevice("sonar");
  if (mySonar == NULL)
    {
      printf("I found no sonar");
      deactivate();
    }
}
/*
  This fire is the whole point of the action.
  currentDesired is the combined desired action from other actions
  previously processed by the action resolver.  In this case, we're
  not interested in that, we will set our desired
  forward velocity in the myDesired member, and return it.

  Note that myDesired must be a class member, since this method
  will return a pointer to myDesired to the caller. If we had
  declared the desired action as a local variable in this method,
  the pointer we returned would be invalid after this method
  returned.
*/
ArActionDesired *ActionGo::fire(ArActionDesired currentDesired)
{
  double range;
  double speed;
  // reset the actionDesired (must be done)
  myDesired.reset();
  // if the sonar is null we can't do anything, so deactivate
  if (mySonar == NULL)
  {
    deactivate();
    return NULL;
  }
  // get the range off the sonar
  range = mySonar->currentReadingPolar(-70, 70) - myRobot->getRobotRadius();
  // if the range is greater than the stop distance, find some speed to go
  if (range > myStopDistance)
  {
    // just an arbitrary speed based on the range
    speed = range * .3;
    // if that speed is greater than our max, cap it
    if (speed > myMaxSpeed)
      speed = myMaxSpeed;
    // now set the velocity
    myDesired.setVel(speed);
  }
  // the range was less than the sop distance, so just stop
  else
  {
    myDesired.setVel(0);
  }
  // return a pointer to the actionDesired, so resolver knows what to do
  return &myDesired;
}


/*
  This is the ActionTurn constructor, note the use of constructor chaining
  with the ArAction. also note how it uses setNextArgument, which makes
  it so that other things can see what parameters this action has, and
  set them.  It also initializes the classes variables.
*/
ActionTurn::ActionTurn(double turnThreshold, double turnAmount) :
  ArAction("Turn")
{
  myTurnThreshold = turnThreshold;
  myTurnAmount = turnAmount;
  setNextArgument(ArArg("turn threshold (mm)", &myTurnThreshold, "The number of mm away from obstacle to begin turnning."));
  setNextArgument(ArArg("turn amount (deg)", &myTurnAmount, "The number of degress to turn if turning."));
  myTurning = 0;
}

/*
  Sets the myRobot pointer (all setRobot overloaded functions must do this),
  finds the sonar device from the robot, and if the sonar isn't there,
  then it deactivates itself.
*/

void ActionTurn::setRobot(ArRobot *robot)
{
  myRobot = robot;
  mySonar = myRobot->findRangeDevice("sonar");
  if (mySonar == NULL)
    deactivate();
}

/*
  This is the guts of the action.
*/
ArActionDesired *ActionTurn::fire(ArActionDesired currentDesired)
{
  double leftRange, rightRange;
  // reset the actionDesired (must be done)
  myDesired.reset();
  // if the sonar is null we can't do anything, so deactivate
  if (mySonar == NULL)
  {
    deactivate();
    return NULL;
  }
  // Get the left readings and right readings off of the sonar
  leftRange = (mySonar->currentReadingPolar(0, 100) -
        myRobot->getRobotRadius());
  rightRange = (mySonar->currentReadingPolar(-100, 0) -
        myRobot->getRobotRadius());
  // if neither left nor right range is within the turn threshold,
  // reset the turning variable and don't turn
  if (leftRange > myTurnThreshold && rightRange > myTurnThreshold)
  {
    myTurning = 0;
    myDesired.setDeltaHeading(0);
  }
  // if we're already turning some direction, keep turning that direction
  else if (myTurning)
  {
    myDesired.setDeltaHeading(myTurnAmount * myTurning);
  }
  // if we're not turning already, but need to, and left is closer, turn right
  // and set the turning variable so we turn the same direction for as long as
  // we need to
  else if (leftRange < rightRange)
  {
    myTurning = -1;
    myDesired.setDeltaHeading(myTurnAmount * myTurning);
  }
  // if we're not turning already, but need to, and right is closer, turn left
  // and set the turning variable so we turn the same direction for as long as
  // we need to
  else
  {
    myTurning = 1;
    myDesired.setDeltaHeading(myTurnAmount * myTurning);
  }
  // return a pointer to the actionDesired, so resolver knows what to do
  return &myDesired;
}



int main(void)
{
  // The connection we'll use to talk to the robot
  ArSerialConnection con;
  // the robot
  ArRobot robot;
  // the sonar device
  ArSonarDevice sonar;
  // some stuff for return values
  int ret;
  std::string str;
  // the behaviors from above, and a stallRecover behavior that uses defaults
  ActionGo go(500, 350);
  ActionTurn turn(400, 10);
  ArActionStallRecover recover;
  // this needs to be done
  Aria::init();
  // open the connection, just using the defaults, if it fails, exit
  if ((ret = con.open()) != 0)
  {
    str = con.getOpenMessage(ret);
    printf("Open failed: %s\n", str.c_str());
    Aria::shutdown();
    return 1;
  }
  // add the range device to the robot, you should add all the range
  // devices and such before you add actions
  robot.addRangeDevice(&sonar);
  // set the robot to use the given connection
  robot.setDeviceConnection(&con);
 
  // do a blocking connect, if it fails exit
  if (!robot.blockingConnect())
  {
  printf("Could not connect to robot... exiting\n");
  Aria::shutdown();
  return 1;
  }
 
  // enable the motors, disable amigobot sounds
  robot.comInt(ArCommands::ENABLE, 1);
  robot.comInt(ArCommands::SOUNDTOG, 0);
  // add our actions in a good order, the integer here is the priority,
  // with higher priority actions going first
  robot.addAction(&recover, 100);
  robot.addAction(&go, 50);
  robot.addAction(&turn, 49);
  // run the robot, 'true' means to return if it loses connection
  robot.run(true);
 
  // now just shutdown and go away
  Aria::shutdown();
  return 0;
}


bharris wrote:Hey. I was looking for some example code on how to write the initiate function for Aria but I couldn't find any. Every example I looked at called the function like this Aria::init() instead of actually creating the function from scratch. I'm assuming that there is already some code created for this function in a library and all we have to do is call that function to initialize Aria.