Robotic Workcell Research Articles

Notes on Feasibility and Optimality Conditions of Small-Scale Multifunction Robotic Cell Scheduling Problems With Pickup Restrictions

Optimization of robotic workcells is a growing concern in automated manufacturing systems. This study develops a methodology to maximize the production rate of a multifunction robot (MFR) operating within a rotationally arranged robotic cell. An MFR is able to perform additional special operations while in transit between transferring parts from adjacent processing stages. Considering the free-pickup scenario, the cycle time formulas are initially developed for small-scale cells where an MFR interacts with either two or three machines. A methodology for finding the optimality regions of all possible permutations is presented. The results are then extended to the no-wait pickup scenario in which all parts must be processed from the input hopper to the output hopper, without any interruption either on or between machines. This analysis enables insightful evaluation of the productivity improvements of MFRs in real-life robotized workcells.

A Literature Survey on Reconfigurable Industrial Robotic Work Cells

As the unpredictability of market needs and the mass customization trends increase, employing reconfigurable industrial robotic work cells becomes a viable solution for manufacturers. A reconfigurable manufacturing system is a system designed for a quick change in structure, both in hardware and software, in order to rapidly adjust production capacity and functionalities. However, the approach is quite general; a simple search within scientific literature, patent databases or the world-wide-web returns thousands of results, covering a time period from the 80s to date. Among the results, different approaches on reconfigurable industrial robotic work cell implementations can be easily noticed. This paper surveys the literature in reconfigurable industrial robotic work cells, aiming to identify, besides the most important approaches on this topic, also performance criteria associated to robotic workcell reconfigurability and means of measuring the reconfigurability degree of such cells. The survey also aims to identify command and control architectures used to achieve various levels of reconfigurability. The survey was conducted by using a specific search methodology, which is also presented in the paper.

Augmented Reality for Telemaintenance and -inspection in Force-Sensitive Industrial Robot Applications

Telematic solutions allow fast remote support in industrial robot work cells: Robotic experts can assist the local staff in work process modifications or in tracking down errors without having to actually travel to the remote site. In order to be able to perform such teleinspection and telemaintenance tasks the operator needs to establish a data connection to the robot and get an understanding of the remote work process, as well as of the transmitted data.This contribution introduces a telematic control system developed for remote monitoring and control of an industrial robot performing force-sensitive work applications. An Augmented Reality interface is proposed for intuitive representation of complex robotic data, allowing quick analysis of the current working cycle and process data and altering the robot's program remotely while still having a clear spatial reference to the work environment.

Virtual Reality Based Support System for Layout Planning and Programming of an Industrial Robotic Work Cell

Traditional robotic work cell design and programming are considered inefficient and outdated in current industrial and market demands. In this research, virtual reality (VR) technology is used to improve human-robot interface, whereby complicated commands or programming knowledge is not required. The proposed solution, known as VR-based Programming of a Robotic Work Cell (VR-Rocell), consists of two sub-programmes, which are VR-Robotic Work Cell Layout (VR-RoWL) and VR-based Robot Teaching System (VR-RoT). VR-RoWL is developed to assign the layout design for an industrial robotic work cell, whereby VR-RoT is developed to overcome safety issues and lack of trained personnel in robot programming. Simple and user-friendly interfaces are designed for inexperienced users to generate robot commands without damaging the robot or interrupting the production line. The user is able to attempt numerous times to attain an optimum solution. A case study is conducted in the Robotics Laboratory to assemble an electronics casing and it is found that the output models are compatible with commercial software without loss of information. Furthermore, the generated KUKA commands are workable when loaded into a commercial simulator. The operation of the actual robotic work cell shows that the errors may be due to the dynamics of the KUKA robot rather than the accuracy of the generated programme. Therefore, it is concluded that the virtual reality based solution approach can be implemented in an industrial robotic work cell.

Ontology based action planning and verification for agile manufacturing

Many of today?s robotic work cells are unable to adapt to even small changes in tasking without significant reprogramming. This results in downtime for production lines anytime a change to a product or procedure must be made. This paper examines a novel knowledge-driven system that provides added agility by removing the programming burden for new activities from the robot and placing it in the knowledge representation. The system is able to automatically recognize and adapt to changes in its work-flow and dynamically change assignment details. The system also provides for action verification and late binding of action parameters, thus providing flexibility by allowing plans to adapt to production errors and changing environmental conditions. The key feature of this system is its knowledge base that contains the necessary relationships and representations to allow for adaptation. This paper presents the ontology that stores this knowledge as well as the overall system architecture. The manufacturing domain of kit construction is examined as a sample test environment. HighlightsWe examine a novel knowledge-driven system that provides added agility.System removes the programming burden for new activities from the robot.System provides for action verification and late binding of action parameters.System adapts to production errors and changing environmental conditions.We present our ontology as well as the overall system architecture.

Agent-Based Systems Approach for Robotic Workcell Integration

This paper presents an approach to the application of agent-based systems for robotic workcell integration. Agent-based systems constitute a relatively new approach for analyzing, designing as well as implementing applications to be used in distributed systems, which is multi-robot workcell described in the paper. This systems should provide coordinated actions of all cooperating agents in order to achieve a common task. In the work was assumed the independent and autonomous operation of each robot as an individual agent. The aim of the designed system was to maximize the number of tasks realized by robots while minimizing the incompatibility of different robots during their joint work. It is assumed the independent operation of each robot and at their highest efficiency and effectiveness. In the paper are presented steps required to reach this aim and the short descriptions of proposed algorithms.

Augmented Reality Aided Control of Industrial Robots

This contribution presents the method of simultaneous control and creation of programming sequences for industrial robot with the use of interactivity achieved in the environment of augmented reality. Paper describes the experimental testing of proposed conception realized at the Faculty of Manufacturing Technologies in Presov of Technical University of Kosice (Slovakia) in the environment of experimental robotic workcell with the use of augmented reality tools. From the viewpoint of displaying units it consider the projection on half-silvered glass as well as using the head mounted display for virtual reality. Final part of the paper summarizes possible trends of further development in described area and also the possibilities of industrial applications.

스케줄링 문제를 위한 멀티로봇 위치 기반 다목적 유전 알고리즘

This paper presents a scheduling problem for a high-density robotic workcell using multi-objective genetic algorithm. We propose a new algorithm based on NSGA-II(Non-dominated Sorting Algorithm-II) which is the most popular algorithm to solve multi-objective optimization problems. To solve the problem efficiently, the proposed algorithm divides the problem into two processes: clustering and scheduling. In clustering process, we focus on multi-robot positions because they are fixed in manufacturing system and have a great effect on task distribution. We test the algorithm by changing multi-robot positions and compare it to previous work. Test results shows that the proposed algorithm is effective under various conditions.

Augmented reality–based programming, planning and simulation of a robotic work cell

In this article, the development of an augmented reality–based robotic work cell is presented, consisting of a virtual robot arm, conveyor belt, pallet and computer numerical control machine that simulates an actual manufacturing plant environment. The kinematics of the robot arm is realized using Denavit–Hartenberg’s theorem, which enables complete manipulation of the end-effector in three-dimensional space when interacting with other virtual machines. Collision detection is implemented in two areas, namely, modifiable marker–based detection for the robot arm, which detects nearby obstacles as well as integration with object manipulation to pick and place a virtual object around the environment. In addition, an augmented heads-up display overlay displays live information of the current system. The case studies suggest that the proposed system can simulate a collision-free operation while displaying the coordinates of the virtual object, current tool equipped and speed of the conveyor belt, with a percentage error of less than 5%.

A workcell calibration method for enhancing accuracy in robot machining of aerospace parts

Industrial robotics provides high flexibility and reconfigurability supported by a user-friendly programming, but still lacks in accuracy. An effective workcell calibration reduces errors in robot manufacturing and enables robot machining applications. A novel workcell calibration method is embedded in an integrated design framework for an in-depth exploitation of CAD-based simulations and offline programming. The method is composed of two steps: first calibration of the workpiece-independent equipment in the workcell layout and final automated online calibration of workpiece-dependent equipment. The method is finally applied to a changeable robotic workcell for finishing aluminium cast housings for aerospace gear transmissions characterised by complex shapes and by close dimensional and geometrical specifications. Experimental results prove the method effectiveness in enhancing accuracy in robot machining.

Implementation of a Voice-ControlSystem for Issuing Commands in a Virtual Manufacturing Simulation Process

Speech recognition is a technology that attempts to involve audio cues during interaction with machines, instead of being limited to just visual and touch interfaces. However, a keyboard and mouse input is an archaic method of interaction, adding on to the fact that voice control is seemingly more natural. This study aims to implement speech recognition as a form of machine control to perform simple commands in a virtual simulation process. The simulation system is an in-house developed augmented reality robotic work cell which includes a robot arm, a conveyer belt, a computer numerical control (CNC) machine, and a pellet. Issuing commands are performed via the Windows Speech Recognition software built from the Microsoft Speech Application Programming Interface (SAPI). This software is advantageous because it can be fairly accurate once trained properly, is easily modifiable by anyone regardless of the operator’s programming knowledge, and is free. A macros tool is used to support the additional features of the recognition software which includes directly programmable Extensible Markup Language (XML) codes.

Robotic Arm for Automated Assembly of Proton Exchange Membrane Fuel Cell Stacks

We present an innovative, inexpensive end-effector, the robot workcell, and the fuel cell components used to demonstrate the automated assembly process of a proton exchange membrane fuel cell stack. The end-effector is capable of handling a variety of fuel cell components including membrane electrode assemblies, bipolar plates and gaskets using vacuum cups mounted on level compensators and connected to a miniature vacuum pump. The end-effector and the fuel cell components are designed with features that allow an accurate component alignment during the assembly process within a tolerance of 0.02 in. and avoiding component overlapping which represents a major cause of overboard gas leaks during the fuel cell operation. The accurate component alignment in the stack is achieved with electrically nonconductive alignment pins permanently mounted on one fuel cell endplate and positioning holes machined on the fuel cell components and on the end-effector. The alignment pins feature a conical tip which eases the engagement between them and the positioning holes. A passive compliance system consisting of two perpendicularly mounted miniature linear blocks and rails allow compensating for the robot's limitations in accuracy and repeatability.

THE CAPABILITY MAP: A TOOL TO ANALYZE ROBOT ARM WORKSPACES

More and more systems are developed that include several robot arms, like humanoid robots or industrial robot systems. These systems are designed for complex tasks to be solved in cooperation by the robot arms. However, the capabilities of the individual robot arms to perform given tasks or the suitability of a multi-robot system for cooperative tasks cannot be intuitively comprehended. For planning complex tasks or designing robot systems, a representation of a robot arm's workspace is needed that allows to determine from which directions objects in the workspace can be reached. In this paper, the capability map is presented. It is a representation of a robot arm's kinematic capabilities in its workspace. The capability map is used to compare existing robot arms, to support the design phase of an anthropomorphic robot arm and to enable robot workcell planning.

Offline Programming for Robotic Deburring Process of Aluminium Wheels

The paper presents application of Siemens RobotExpert software of industrial robot offline programming. The deburring process of aluminium wheel is described and developed. The robotic work-cell contains robot ABB IRB 1600id and two axes positioner ABB IRBP A 750 D 1000 H 700. The final robot tool path is checked using the collision viewer, the joint status monitor, the tool centre point speed viewer and tracker.

Visual Reconstruction and Optimization of Real Workplace on the Base of Spatial Digitisation

This article provides perspective into creation of virtual 3D model of existing robotic workcell to optimize productive process and save space. Separate parts of the paper describe the process of creation of the environment with the usage of an alternative scanning device, namely Kinect in combination with various software applications. This alternative offers scans of environment and components surfaces that are from the viewpoint of precision and quality comparable with much more expensive devices but based only on open source elements.

On the Development of a Specialized Flexible Gripper for Garment Handling

In this paper, we discuss ongoing work on the development of a new griper for garments handling and manipulation tasks. We analyze the specificity of the application determining the requirements for the design and functioning of the grasping system. Textiles do not have a stable shape and cannot be manipulated on the basis of a priori geometric knowledge. Therefore, the grasping task cannot be executed without exploring the material and the environment. This is to be achieved by a vision system, which is part of the robotic work cell, in combination with tactile sensors embedded in the fingertips of the gripper. A possible design for the gripper mechanism is outlined and open research and design problems are identified. 

A Web-Based Integration Procedure for the Development of Reconfigurable Robotic Work-Cells

Concepts related to the development of reconfigurable manufacturing systems (RMS) and methodologies to provide the best practices in the processing industry and factory automation, such as system integration and web-based technology, are major issues in designing next-generation manufacturing systems (NGMS). Adaptable and integrable devices are crucial for the success of NGMS. In robotic cells the integration of manufacturing components is essential to accelerate system adaptability. Sensors, control architectures and communication technologies have contributed to achieving further agility in reconfigurable factories. In this work a web-based robotic cell integration procedure is proposed to aid the identification of reconfigurable issues and requirements. This methodology is applied to an industrial robot manipulator to enhance system flexibility towards the development of a reconfigurable robotic platform.

Evaluation of UV-C Mutagenized Scheffersomyces stipitis Strains for Ethanol Production

We evaluated fermentation capabilities of five strains of Scheffersomyces stipitis (WT-2-1, WT-1-11, 14-2-6, 22-1-1, and 22-1-12) that had been produced by UV-C mutagenesis and selection for improved xylose fermentation to ethanol using an integrated automated robotic work cell. They were incubated under both facultative and anaerobic conditions to evaluate ethanol production on glucose, xylose, cellobiose, and a combination of all three sugars. The medium contained 50 g/L total sugar and 5 g/L yeast extract. The strains performed significantly better under facultative compared with anaerobic conditions. As expected, glucose was the most readily fermented sugar with ~100% fermentation efficiency (FE) under facultative conditions but only 5% to 16% FE anaerobically. Xylose utilization was 20% to 40% FE under facultative conditions but 9% to 25% FE anaerobically. Cellobiose was the least fermented sugar, at 18% to 27% FE facultatively and 8% to 11% anaerobically. Similar trends occurred in the sugar mixture. Under facultative conditions, strain 22-1-12 produced 19.6 g/L ethanol on glucose, but strain 14-2-6 performed best on xylose (4.5 g/L ethanol) and the sugar combination (8.0 g/L ethanol). Ethanol titers from glucose under anaerobic conditions were again highest with strain 22-1-12, but none of the strains produced ethanol from xylose. Future trials will evaluate nutrient addition to boost microaerophilic xylose fermentation.

Periodic Schedules for Bounded Timed Weighted Event Graphs

Timed event graphs (TEGs) and timed weighted event graphs (TWEGs), which have multiple arc cardinalities, have been widely used for automated production systems such as robotic work cells or embedded systems. TWEGs are useful for modeling batch flows of entities such as batch arrivals or processing of jobs. Periodic schedules, that combine an explicit description of starting times and an easy implementation, are particularly interesting, and have been proved to be optimal for ordinary timed event graphs (TEGs). In this paper, we present polynomial algorithms to check the existence of periodic schedules of bounded TWEGs and to compute their optimal throughput. These results can be considered as generalizations of those for ordinary timed event graphs. We then establish that periodic schedules are suboptimal for TWEGs and may not exist even for a live TWEG. The gap between optimal throughput and throughput of an optimal periodic schedule is experimentally investigated for a subclass of TWEGs, namely timed weighted circuits.

Automated Systems.

Automated Systems.