Cezary Zieliński

Motion Generation in the MRROC++ Robot Programming Framework

In this paper we present a formal approach to robot motion specification. This motion specification takes into account three elementary behaviors that suffice to define any robot interaction with the environment, i.e. free motion, exerting generalized forces and the transition between both of these behaviors. These behaviors provide a foundation for general motion generation taking into account any sensors, any effectors and the capability to exchange information between embodied agents. This specification can be used both for the definition of robot tasks and implementation of robot control software, hence both of those aspects are presented in this paper. This formal approach was used for the implementation of the MRROC++ robot programming framework. Two-handed manipulation of a Rubik’s cube is used as an exemplary task. Extensive experimentation both with the presented formalism and the MRROC++ framework showed that the imposed formal rigor eliminates many errors at the software specification phase, produces well-structured control software and significantly speeds up and simplifies its implementation. These advantages are mainly due to the fact that the proposed formal specification tool is derived from operational semantics used in computer science for the definition of programming languages, thus a close relationship between abstract definition and the implementation of the control system resulted.

Recent Advances in Automation, Robotics and Measuring Techniques

This book presents the recent advances and developments in control, automation, robotics and measuring techniques. It presents contributions of top experts in the fields, focused on both theory and industrial practice. The particular chapters present a deep analysis of a specific technical problem which is in general followed by a numerical analysis and simulation and results of an implementation for the solution of a real world problem. The book presents the results of the International Conference AUTOMATION 2014 held 26 - 28 March, 2014 in Warsaw, Poland on Automation Innovations and Future Prospectives The presented theoretical results, practical solutions and guidelines will be useful for both researchers working in the area of engineering sciences and for practitioners solving industrial problems.

Object-oriented robot programming

The paper presents an object-oriented approach to the implementation of a software library (MRROC+) which contains building blocks for the construction of multi-robot system controllers tailored to meet specific demands of a task at hand. Moreover, the paper supplies a brief overview of robot programming methods.

The MRROC++ system

The paper proposes a structure for open, hierarchical, multi-device controllers. The proposed structure takes into account that the system may contain several robots of different type, a certain number of cooperating devices, diverse sensors and also the fact that the task, the system has to execute, and the number and type of its components may vary considerably over time. The concept has been verified by designing a controller for a prototype RNT robot and an ASEA IRb-6 type robot. The flexibility of the system is due to the software, so the programming aspect is treated in detail.

Torbol: an object level robot programming language

Abstract Mechatronic devices need a user-friendly human interaction interface. The more complex the device, the more important is the way of communicating with it. This paper presents a brief specification of a robot programming language. An example of a program controlling the execution of a simple industrial task is also provided. Although TORBOL is a robot programming language, there is no need of referring to the notion of a robot in the text of the program. The user has only to define the objects in the robot environment and the relations that have to take place between them. The programmer is completely released (by the compiler) from an obligation of specifying the consecutive positions of the robot arm. The user concentrates on the relations between the objects that have to take place in the following phases of the industrial process, and the compiler determines all the necessary motions of the robot. In this way, the TORBOL user determines only what has to be done and not how it is to be done. The text of the program written in TORBOL is a sequence of descriptions of situations. The language also takes into account reasons of changes in the state of the environment other than those caused by the controlled robot.

Rubik's cube as a benchmark validating MRROC++ as an implementation tool for service robot control systems

Purpose – This paper seeks to develop universal software (a programming framework) enabling the implementation of service robot controllers. The software should distinguish the hardware‐oriented part of the system from the task‐oriented one. Moreover, force, vision as well as other sensors should be taken into account. Multi‐effector systems have to be considered.Design/methodology/approach – The robot programming framework MRROC++ has been implemented as a hierarchical structure composed of processes, potentially consisting of threads. All of the software is written in an object‐oriented manner using C++ and is supervised by a QNX real‐time operating system. The framework has been verified on several systems executing diverse tasks. Here, a Rubiks cube puzzle‐solving system, consisting of two arms and utilizing force control and visual servos, is presented.Findings – The presented framework is well suited to tasks requiring two‐handed manipulation with force sensing, visual servoing and online construct...

Transition-Function Based Approach to Structuring Robot Control Software

Whenever control software is to be coded for a new piece of equipment or for a new task that it has to execute, we notice that there is considerable similarity with the code that has been produced previously for alike devices and tasks. However, if the previously produced software does not have a structure facilitating its reuse it is usually very difficult to extract the useful portions. Moreover, any modification or extension of the old software might be hindered by its inadequate structure. This is especially true for robot control software. It is relatively easy to produce code for a specific device and a specific task, but when those change, it is sometimes easier to start coding from scratch than try to reuse the old pieces. The problem that we want to tackle in this paper is: whether we can give some insight into structuring the robot system control software without a priori knowledge of: the exact type of hardware (robot, sensors) that will be used, the number of controlled devices, the task that will be executed by the system, the control paradigm employed (e.g., behavioural, deliberative).

Structures of visual servos

The paper classifies visual servos and using this classification derives their possible structures. It also analyzes the influence of robot-model calibration and robot-camera calibration on the derived control structures. The systematic derivation of possible structures of visual servos enabled the creation of software patterns within the MRROC++ (Zielinski et al., 2007) [29] robot programming framework facilitating their implementation. Those considerations are preceded by a brief introduction defining the principal concepts used in the paper. The paper is concluded by presenting the use of the derived structures in the experiments with grasping static and tracking moving objects. The paper highlights the advantages and drawbacks of the presented structures.

A systematic method of designing control systems for service and field robots

The paper presents a systematic approach to robot control system design. The robot is treated as an embodied agent decomposed into effectors, receptors, both real and virtual, and a control subsystem. Those entities communicate through communication buffers. The activities of those entities are governed by FSMs that invoke behaviours formulated in terms of transition functions taking as arguments the contents of input buffers and producing the values inserted into output buffers. The method is exemplified by applying it to a design of a control system of a robot capable of locating an open box and covering it with a lid. Other systems that have been designed in a similar way are presented as well, to demonstrate the versatility of the approach.

Control and programming of a multi‐robot‐based reconfigurable fixture

Purpose – Machining fixtures must fit exactly the work piece to support it appropriately. Even slight change in the design of the work piece renders the costly fixture useless. Substitution of traditional fixtures by a programmable multi‐robot system supporting the work pieces requires a specific control system and a specific programming method enabling its quick reconfiguration. The purpose of this paper is to develop a novel approach to task planning (programming) of the reconfigurable fixture system.Design/methodology/approach – The multi‐robot control system has been designed following a formal approach based on the definition of the system structure in terms of agents and transition function definition of their behaviour. Thus, a modular system resulted, enabling software parameterisation. This facilitated the introduction of changes brought about by testing different variants of the mechanical structure of the system. A novel approach to task planning (programming) of the reconfigurable fixture syst...