case study 4

Desired features of Mobile Robotics Architecture

Dr Reeja S RProfessorCSE Dept.SJEC, Vamanjoor,

Mangalore

Desired features of Mobile Robotics Architecture1. Supports deliberate and reactive behavior. (ex: collect

a rock sample) (ex: avoid an obstacle)

2. Allows uncertainty and unpredictability of environment. (such as contradictory sensor readings).

3. System must consider possible dangerous operations by Robot and in its environment (Ex: reduced power supply, dangerous vapors, unexpectedly opening doors of hazardous materials, etc)

4. The system must give the designer flexibility of experimentation and reconfiguration (mission’s change/requirement changes)

Solution #3: Implicit Invocation

Implicit invocation using exception handler, wiretapping and monitors

REQ #1:Supports Deliberate and reactive behavior

Deliberate : Task trees Reactive: exceptions, wiretapping and monitors

REQ #2:Should operate with incomplete and unreliable info

Create tentative task trees which are then modified by exception handlers when exceptional event occurs.

REQ #3:Account for danger Exception, wiretapping and monitors

address needs for performance, safety and fault tolerance

REQ #4:Design for flexibility (experimentation and reconfiguration)

For dynamic Reconfiguration, It is often sufficient to register new handlers, exceptions, wiretaps, or monitors with central server; no existing components are affected.

Solution #4: Blackboard

•The “captain”, the overall supervisor.

•The “map navigator”, the high level path planner.

•The “lookout”, a module that monitors the environment for landmarks.

•The “pilot”, the low level path planner and motor controller.

•The perception subsystem, the modules that accept the raw input from multiple sensors and integrate it into a coherent interpretation.

REQ #1:Deliberate and reactive behavior

Achieved using blackboard

REQ #2:Should operate with incomplete and unreliable info

The blackboard acts as a means of resolving uncertainties.

REQ #3:Account for danger Exception handling, wiretapping,

monitors can be used for certain signs of problematic situations

REQ #4:Design for flexibility (experimentation and reconfiguration)

Supports concurrencySeparates senders from receivers

Cruise Control System

Case Study #4

Cruise control- problem statement

Whenever the system is active, determine the desired speed, and control the engine throttle setting to maintain that speed.

Block diagram for cruise control

Booch’s OOD for cruise control

Process control view of cruise control

The cruise control system is supposed to maintain constant speed in an automobile despite variations in terrain, vehicle load, air resistance, fuel quality, etc.