Event-driven industrial robot control architecture for the Adept V+ platform.

Oleksandr Semeniuta,Petter Falkman

doi:10.7717/peerj-cs.207

Abstract

Modern industrial robotic systems are highly interconnected. They operate in a distributed environment and communicate with sensors, computer vision systems, mechatronic devices, and computational components. On the fundamental level, communication and coordination between all parties in such distributed system are characterized by discrete event behavior. The latter is largely attributed to the specifics of communication over the network, which, in terms, facilitates asynchronous programming and explicit event handling. In addition, on the conceptual level, events are an important building block for realizing reactivity and coordination. Event-driven architecture has manifested its effectiveness for building loosely-coupled systems based on publish-subscribe middleware, either general-purpose or robotic-oriented. Despite all the advances in middleware, industrial robots remain difficult to program in context of distributed systems, to a large extent due to the limitation of the native robot platforms. This paper proposes an architecture for flexible event-based control of industrial robots based on the Adept V+ platform. The architecture is based on the robot controller providing a TCP/IP server and a collection of robot skills, and a high-level control module deployed to a dedicated computing device. The control module possesses bidirectional communication with the robot controller and publish/subscribe messaging with external systems. It is programmed in asynchronous style using pyadept, a Python library based on Python coroutines, AsyncIO event loop and ZeroMQ middleware. The proposed solution facilitates integration of Adept robots into distributed environments and building more flexible robotic solutions with event-based logic.

Highlights

Robots are always associated with high level of complexity, which is usually considered with respect to the task being performed
Big advantage of the proposed architecture is that the robot controller is treated as a service: once the server task is launched, the central application logic is driven by the Python-based MasterControlNode
This paper has presented an industrial robot control architecture for the Adept V+ platform that aims at maximizing flexibility of system development

Summary

INTRODUCTION

Robots are always associated with high level of complexity, which is usually considered with respect to the task being performed. Many robot systems need to respond at varying temporal scopes—from millisecond feedback control to minutes, or hours, for complex tasks’’ This is the reason why robotic architecture becomes increasingly important. The main idea is to treat the robot and external nodes (such as vision systems) as services, and coordinate communication with them from a high-level control node. The logic of the latter is composed from a set of Python AsyncIO coroutines based on domain-specific abstractions. The architecture facilitates specification of event-driven communication logic and internal asynchronous runtime As a result, it becomes easier, more flexible, and less error-prone to program industrial robots and integrate them into distributed environments.

BACKGROUND

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DISCUSSION

SUMMARY AND FURTHER WORK