Task

Your task is to design a subsumption hierarchy for the robot that will deliver patient supplies from the supply counter to the patient's room.

The robot has five behaviors: move forward, follow wall, escape, enter doorway, and rfid found . Your subsumption architecture will assign a priority to each of these behaviors. Remember that in a subsumption architecture many behaviors are operating in parallel, competing for control of the motors. By assigning a priority to each of these behaviors, you will control which behaviors get control. A correct ordering will produce a coordinated behavior that results in the robot making it into the patient room. Once the robot is in the room, it will stop moving. Incorrect orderings will cause the robot to do other things, such as crash into walls, wander aimlessly, or simply stop moving in the middle of the hallway.

The robot is equipped with two different kinds of sensors. A laser ranging system provides information about how far away things are in the environment. The robot can use this information to detect walls, obstacles, and doorways. An RFID sensor indicates the presence of an RFID tag in the environment. RFID stands for Radio-Frequency IDentification; an RFID tag is a small electronic tag that emits a signal that can uniquely identify it. In this hospital, each door is marked with an RFID signal. When the robot embarks on a delivery, it can use the RFID tags to locate a specific room.

Hints:

• Don't try and use all of the behaviors right away. Start with just one or two behaviors.
• Some behaviors are "always on" some must be " triggered" by something in the environment. For example, the rfid found behavior activates whenever the robot senses an RFID tag in the environment. Try to figure out how each one works.
• Try to figure out the simplest subsumption architecture that will let the robot navigate. If you get the robot moving through the hospital without crashing into things, congratulations! You are very close to the solution. Once you've got this, you know what order those behaviors need to be in. Then try to fit the other behaviors into the hierarchy as well.