Tomasz Winiarski

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.

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...

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.

Opening a door with a redundant impedance controlled robot

Opening a door with a robotic manipulator equipped with a gripper, is a vital problem in service robotics research. This paper presents an approach to opening a cabinet door with an impedance controlled 7-DOF redundant manipulator. A control system is developed that considers redundancy in order to maximise the manipulation capabilities of the manipulator whilst avoiding reaching the joints limits. The control strategy is based on automatically estimating the kinematic parameters of the door. All conducted experiments were based on the assumption that the manipulator pulls a handle and opens a door using a single finger.

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...

Indirect force control development procedure

Addition of extra sensors, especially video cameras and force sensors, under control of appropriate software makes robotic manipulators working in factories suitable for a range of new applications. The article presents a method of manipulator indirect force control development, in which the force set values are specified in the operational space and the manipulator is equipped with a force sensor in its wrist. Standard control development methods need an estimation of parameters of the detailed model of a manipulator and position servos, what is a complicated and time consuming task. Hence in this work a time efficient hybrid procedure of controller development is proposed consisting of both an analytical and experimental stages: proposal of an approximate continuous model of a manipulator, experimental determination and verification of its parameter values using the resonance phenomenon, continuous regulator development, digitization of the regulator. keywords: manipulator control, indirect force control, controller development

Specification of a Multi-agent Robot-Based Reconfigurable Fixture Control System

The paper presents a formal specification of the control software of a reconfigurable fixture used for machining thin plates. The fixture is based on relocatable supporting robots. A multi-agent approach to control system structuring is used. The behaviour of agents is defined in terms of finite state automatons, transition functions, and terminal conditions.

Applications of MRROC++ robot programming framework

The paper concentrates on the way that the MRROC++ robot programming framework has been applied to produce control systems for robots of different types performing diverse tasks. Moreover, both a brief formal specification and the method of implementation of the MRROC ++ based system is presented.

Research Oriented Motor Controllers for Robotic Applications

Motor controllers are vital parts of robotic manipulators as well as their grippers. Typical, commercial motor controllers available on the market are developed to work with high level robot industrial controllers, hence their adaptation to work as a part of a scientific, experimental robotic system is problematic. The general concept of research oriented motor controllers for robotic systems is presented in this article as well as an exemplary gripper and manipulator application based on this concept.

Control Architecture for Sensor-Based Two-Handed Manipulation

In this paper we propose a sensor-based control architecture for two-handed robotic manipulation in a partially structured environment. We deal with two major aspects of sensor-based manipulation: visual localisation and recognition of objects and utilization of force and torque measurements. We also take into account that service robots should be endowed with reasoning capabilities about motions that have to executed and that high level operations must be translated into trajectories to be executed by the manipulators. As a benchmark task we chose the manipulation of Rubik’s cube.