Modelling the Turtle Python library in CSP

TL;DR

This paper introduces CSP2Turtle, a toolchain that models Python's Turtle library in CSP to verify robot navigation plans, aiming to improve reliability in robotic systems.

Contribution

It presents a formal CSP model of the Turtle library and an interactive verification toolchain for pre-execution plan validation in robotics.

Findings

CSP2Turtle enables verification of Turtle plans before execution.

The approach helps prevent certain classes of errors in robotic navigation.

Examples demonstrate effective plan verification in grid-world scenarios.

Abstract

Software verification is an important tool in establishing the reliability of critical systems. One potential area of application is in the field of robotics, as robots take on more tasks in both day-to-day areas and highly specialised domains. Robots are usually given a plan to follow, if there are errors in this plan the robot will not perform reliably. The capability to check plans for errors in advance could prevent this. Python is a popular programming language in the robotics domain, through the use of the Robot Operating System (ROS) and various other libraries. Python's Turtle package provides a mobile agent, which we formally model here using Communicating Sequential Processes (CSP). Our interactive toolchain CSP2Turtle with CSP model and Python components, enables Turtle plans to be verified in CSP before being executed in Python. This means that certain classes of errors can be avoided, and provides a starting point for more detailed verification of Turtle programs and more complex robotic systems. We illustrate our approach with examples of robot navigation and obstacle avoidance in a 2D grid-world.