Reactive Paradigm

1
Reactive Paradigm

• Why Study RP?
• Robotic Systems are still being constructed using
  RP.
• Helps Understand Hybrid Paradigm

2
Basic Difference

• HP has horizontal decomposition (HD)
• RP has vertical decomposition (VD)
• Difference between HD and VD
• In VD many processes can be performed
  simultaneously.
• Breathing can continue while writing, sleeping,
  etc.

3
Behaviors in RPTwo approaches

• Subsumption (Brooks)
• Insect Like robots (hardware circuitory captures
  behaviour)
• Potential Fields (Arkin and Payton)
• Easy to implement in software
• Behaviour represented as vector, difference
  vectors are summed to produce emergent behaviour.

4
Subsumption

• Behaviour a collection (network) of sensing and
  acting that accomplishes the task.
• Behaviours are released in a stimulus-response
  way, without an external program interacting
  explicitly from outside the body of the robot.

5
Aspects of Subsumption

• Layers of competence
• In these layers intelligence according to its
  complexity is stored.
• Basic intelligence at the lower layers.
• Modules in the upper layer can override the lower
  layers
• No knowledge of the localized topology is
  maintained.
• TASK Any appropriate layer is activated which
  further activates lower layers if required.

6
Example

• Design a Robot that could move forward without
  colliding.
• Guess how many sensors would be required?
• How many actuators will be required?

7
Answers

• Multiple Sensors (say 10)
• At least two actuators
• Sensing SONAR BASED
• Produce a polar plot (range of sensor readings in
  polar coordinates (r , theta))
• Detect when not to move forward