This thesis has described an investigation into the complementary problems of map-building and exploration by a mobile robot. This chapter highlights the most significant results of this investigation.

The novel contribution of this research can be summarised as:

• • The integration of a physical robot, a sonar model, map construction algorithms, and a localisation algorithm into an effective working system;

• • The definition and implementation of a novel quantitative measure of map quality;

• • A thorough quantitative and statistical evaluation of the map-building and exploration capabilities of the system, using the quality metric and a variety of exploration strategies.

The system components and the quality metric were described in Part II of this thesis. Sections 19.1 to 19.4 briefly review these topics. The experimental evaluation of exploration strategies formed the bulk of Part III of this thesis. The results of this work have already been summarised in Chapter 18.

Chapter 2 described the continuing debate between the ‘traditional’ supporters of modelbased robotics and the proponents of behaviour-based robotics. An outcome of the current research has been an awareness of the need to balance these two approaches. The value of reactive navigation became more apparent as the research progressed. Section 19.5 reviews the course of the research in the context of the ‘models versus behaviours’ debate.

19.1 The Ultrasonic Sensor Model

Chapter 6 presented a set of experimental results which showed how the Polaroid ultrasonic rangefmder detected each type of object that would be encountered in the test environments.