ARCHITECTURAL PROBLEMS OF THE HYBRID POSITION AND FORCE CONTROL SYSTEM OF ROBOTS

An experimental robot control system has been developed at the Budapest Technical University, providing access for research and development in terms of modern robot control algorithms. The multiprocessor robot control system is connected to a NOKIA-PUMA 560 humanoid robot arm. The purpose of this study is to discuss the architectural problems of the mentioned multiprocessor control system. The guiding principles of the modern hybrid position-force control are explained and the structure of the multiprocessor control system is presented. The tasks of the components and the features of the communication channels are also discussed. Finally, the study gives the summary of the architectural and communication requirements of a hybrid position and force control system in the above environment

SOFTWARE PROBLEMS OF AN EXPERIMENTAL ROBOT CONTROLLER BASED ON QNX REAL-TIME OPERATING SYSTEMS

At the Department of Automation and Applied Informatics an experimental robot control system has been developed. The purpose of this research is to study modern robot control algorithms and their realization in a real environment. The project focuses on the problems of multiprocessor systems including the task distribution and communication. Another field of this research is to integrate a six-component force-torque sensor into the robot control system and making use of this information in new robot control algorithms. Another purpose of this study is to examine the software problems of an IBM PC-based multiprocessor system controlling a NOKIA-PUMA 560 humanoid robot arm. The features and system services of the new QNX Neutrino operating system is presented in comparison with the previously used QNX v4. The main areas of the version upgrade will be shown focusing on the interprocess communication questions. The processing components of this multiprocessor robot control system with its external interfaces will be discussed later and some further system level development possibilities will be outlined. This final part of the study gives the summary of the architectural and communication requirements of a hybrid position and force control system in the above environment

Hybrid position and force control algorithm expansion of a robot control system

At the Technical University of Budapest within the scope of a project supported by the Hungarian Research Fund (OTKA, grant No. T029072) an experimental robot control system has been developed. Last year a new component, a six-axis force/torque sensor and the related control unit were added to the system, allowing to implement the hybrid position and force control algorithm. The purpose of this study is to describe the new hardware component and its tasks within the control system. The paper presents an overview of the control algorithm and summarises the architecture of the experimental robot control and the force/torque sensor systems. Then the architecture of the hardware designed and its computing task are outlined. Finally, estimation for the cycle time required by the calculations is given

Nonholonomic Path Planning for a Point Robot with Car-Like Kinematics

A new approach of nonholonomic path planning for car-like robots is presented. The main idea is similar to many existing approaches which obtain a path in two phases. It is familiar in nonholonomic planning that at first a holonomic path is planned which is approximated by a nonholonomic one in a second step by subdividing it into smaller parts and replacing them with local paths fulfilling the kinematic constraints. These methods mostly rely on probabilistic methods and heuristic optimization. Our approach uses a holonomic preliminary path as well, but it serves only as a "loose guidance" to the second phase of the planning process. The final path is not required to contain any of the intermediate points of the preliminary path at all. The method is effective in environments consisting of narrow corridors but having wider free areas as well which can be used for maneuvering

Corner Detection and Classification of Simple Objects in Low-Depth Resolution Range Images

This paper deals with corner detection of simple geometric objects in quantized range images. Low depth resolution and noise introduce challenges in edge and corner detection. Corner detection and classification is based on layer by layer depth data extraction and morphologic operations. Appearance based heuristics are applied to identify different corner types defined in this paper. Both computer generated and captured range images are dealt with. Synthetic range images have arbitrary range resolution while captured images are based on the sensor used. Real world data is collected using a structured light based sensor to provide dense range map

A Model Predictive Navigation Approach Considering Mobile Robot Shape and Dynamics

Most mobile robot navigation approaches assume the robot being point-like or consider only its bounding circle while looking for a collision-free path to a given goal position. A well-known method called the Dynamic Window Approach (DWA) introduced an interesting idea for solving the navigation problem by local optimization in the control space of the robot. Some extensions of the original DWA method can also be found in the literature, which enable its applicability to holonomic and non-holonomic robots and ensure a global and safe solution to the navigation problem. The method described in this paper has also been motivated by the basic idea of dynamic window and contributes to the previous variants by taking the robot shape into consideration as well. A navigation function based model predictive control scheme is utilized to choose the appropriate control for a safe and successful navigation

A LOW-COST ROBOT CONTROLLER AND ITS SOFTWARE PROBLEMS

In recent years the need for advanced robot control algorithms for industrial robots has grown. The deyelopment of a low-cost robot controller to support the development, implementation and testing of those algorithms which require high computational power was targeted. This paper deals wiith the requirements of an experimental controller that can be connected to a NOKIA PUMA 560 robot arm. It explains the IBM PC compatible host and the TEXAS Digital Signal Processor (DSP) based hardware. On the host computer the UNIX-like QXX real-time operating system is used. In the current phase of development the robot controller works with the classical decentralised joint control based strategy. The Advanced Robot Pogramming System (ARPS) explicit robot programming, language is implementedl

Autonóm robotok korszerű irányításelméletének, navigációjának és az intelligencia növelésének kutatása = Research in the advanced control theory and navigation of autonomous robots and the increase of the intelligence

Módszereket dolgoztunk ki redundáns mobilis robotok mozgásának koordinálására es a mozgás optimális megosztására a platform és a robot között. Rétegezett irányításon és játékelméleten alapuló mozgástervezési és irányítási algoritmusokat dolgoztunk ki multiágensű rendszerek számára. Tárgymanipulációs algoritmusokat fejlesztettünk ki kooperáló robotok és többujjas robotkezek irányításához mesterséges intelligencia eszközök bevonásával. Módszereket adtunk járművek és intelligens beavatkozó szerveik modellezésére, pályatervezésére és korszerű irányításukra. Adaptív irányítási algoritmusokat fejlesztettünk ki mechatronikai rendszerek és robotok súrlódási jelenségeinek modellezésére és kompenzálására. Földi járművek automatikus akadályelerülésére pályatervezési módszert és prediktív irányítási algoritmust dolgoztunk ki. Sztereó képfeldolgozási módszereket fejlesztettünk ki a 3D jelenet rekonstruálására, az objektumok felismerésére és a tárgyak relatív helyzetének meghatározására. Robotok kézmozdulatokkal történő irányításához és a teleoperációhoz kidolgoztuk az emberi kéz részletes kinematikai modelljét. Mobilis és mikrorobotok viselkedésorientált irányításához platform független szimulátort fejlesztettünk ki, amely csökkenti a tervezési fázis költségét és a meghibásodás kockázatát. Ipari robot hibrid pozíció/erő irányításához új architektúrát, kommunikációs megoldásokat és szoftver platformot fejlesztettünk ki, amely megkönnyíti a valósidejű irányító szoftverek fejlesztését. | Methods were developed to coordinate the motion of redundant mobile robots allowing optimal task distribution between platform and robot arm. Motion design and control algorithms using stratified control and game theory were developed for multiagent systems. Object manipulation algorithms were elaborated to the control of cooperating robots and multifingered dexterous hands integrating artificial intelligence tools. Methods were given for modeling, path design, and advanced control of vehicles and their intelligent actuators. Adaptive control algorithms were developed for friction modeling and compensation in mechatronic and robotic systems. A path design method and a predictive control algorithm were elaborated for Collision Avoidance Systems of ground vehicles. Stereo image processing methods were developed for 3D reconstruction, object recognition, and for the determination of the relative pose among objects. A detailed kinematic model of the human hand was elaborated for the control and teleoperation of robots by hand gestures. A platform independent simulator was developed for the behavior based control of mobile and micro robots which decreases the cost of the design phase and reduces the risk of failures. A new architecture, communication solutions, and a software platform were developed for the hybrid position/force control of industrial robots facilitating the design of the real time control software tools

Autonomous Path Planning for Road Vehicles in Narrow Environments: An Efficient Continuous Curvature Approach

In this paper we introduce a novel method for obtaining good quality paths for autonomous road vehicles (e.g., cars or buses) in narrow environments. There are many traffic situations in urban scenarios where nontrivial maneuvering in narrow places is necessary. Navigating in cluttered parking lots or having to avoid obstacles blocking the way and finding a detour even in narrow streets are challenging, especially if the vehicle has large dimensions like a bus. We present a combined approximation-based approach to solve the path planning problem in such situations. Our approach consists of a global planner which generates a preliminary path consisting of straight and turning-in-place primitives and a local planner which is used to make the preliminary path feasible to car-like vehicles. The approximation methodology is well known in the literature; however, both components proposed in this paper differ from existing similar planning methods. The approximation process with the proposed local planner is proven to be convergent for any preliminary global paths. The resulting path has continuous curvature which renders our method well suited for application on real vehicles. Simulation experiments show that the proposed method outperforms similar approaches in terms of path quality in complicated planning tasks

Camera placement optimization in object localization systems

\u3cp\u3eThis paper focuses on the placement of cameras in order to achieve the highest possible localization accuracy with a multi-camera system. The cameras have redundant fields of view. They have to be placed according to some natural constraints but user defined constraints are allowed as well. A camera model is described and the components causing the localization errors are identified. Some localization accuracy measures are defined for any number of cameras. The multi-camera placement is analytically formulated using the expanded measures for multiple cameras. An example of placing two cameras is shown and the generalizations into higher dimensional parameter spaces are examined. There are publications where camera placement algorithms are formulated or compared. We make an attempt to examine the analytical solution of this problem in case of different objective functions.\u3c/p\u3