Search

This paper presents a modeling method of weld bead profiles deposited on uneven base metal surfaces and its application in multi-pass welding. The robotized multi-pass tungsten inert gas welding requires precise positioning of the weld beads to avoid welding defects and achieve the desirable welding join since the weld bead shapes depend on the surface of the previously deposited beads. The proposed model consists of fuzzy systems to estimate the coefficients of the profile function. The characteristic points of the trapezoidal membership functions in the rule bases are tuned by the Bacterial Memetic Algorithm during supervised training. The fuzzy systems are structured as multiple-input-single-output systems, where the inputs are the welding process variables and the coefficients of the shape functions of the segments underlying the modeled bead; the outputs are the coefficients of the bead shape function. Each segment surface is approximated by a second-order polynomial function defined in the weld bead’s local coordinate system. The model is developed from empirical data collected from single and multi-pass welding. The performance of the proposed model is compared with a multiple linear regression model. During the experimental validation, first, the individual beads are evaluated by comparing the estimated coefficients of the profile function and other bead characteristics (bead area, width, contact angles, and position of the toe points) with the measurements, and the estimations of a multiple linear regression model. Second, the sequential placement of the weld beads is evaluated while filling a straight V-groove by comparing the estimated bead characteristics with the measurements and calculating the accumulated error of the filled groove cross-section. The results show that the proposed model provides a good estimation of the bead shapes during deposition on uneven base metal surfaces and outperforms the regression model with low error in both validation cases. Furthermore, it is experimentally validated that the derived bead characteristics provide a suitable measure to identify locations sensitive to welding defects.

In this paper, the use of a monitoring companion is proposed to more efficiently collect the process information during the tuning of industrial systems, and therefore to assist the system integrator in the optimization process for complex robotic installations. The monitoring companion consists of an industrial manipulator (monitoring robot) and a Unity-ROS framework for controlling it. We discuss in this paper the features that allow the solution to be re-used in different industrial application thanks to its compatibility with ROS. In particular, we present the approach based on admittance virtual fixtures and how we use such abstraction to track a moving target (it could be the end-effector of another robot for example). Moreover, the concept of varying compliance is introduced as a way to influence the motion of the monitoring robot on the virtual fixtures in the presence of obstacles. The experiments have been conducted in simulation as well as on real hardware to test the accuracy of the system at respecting the virtual fixtures with both a static and a moving monitoring target, although in the current implementation the varying compliance was not included in the experiments.

Worldwide, the focus on industrial development is on achieving smaller and smaller batch sizes in production. This has led to the need for providing cost efficient support to robot users. In this study, a new method for the remote operation of industrial robot systems is introduced. The method is based upon multi-modal man-machine communication and sensor bridging to transfer huge amounts of information from the industrial robot cell to the brain of the remote operator.

In an increasing demand for human-robot collaboration systems, the need for safe robots is crucial. This paper presents a proactive strategy to enable an awareness of the current risk for the robot. The awareness is based upon a map of historically occupied space by the operator. The map is built based on a risk evaluation of each pose presented by the operator. The risk evaluation results in a risk field that can be used to evaluate the risk of a collaborative task. Based on this risk field, a control algorithm that constantly reduces the current risk within its task constraints was developed. Kinematic redundancy was exploited for simultaneous task performance within task constraints, and risk minimization. Sphere-based geometric models were used both for the human and robot. The strategy was tested in simulation, and implemented and experimentally tested on a NACHI MR20 7-axes industrial robot.

Using robots for heavy welding application is a growing field of automation; numerous development project carried out for the ship manufacturing or the offshore industry. However, most of the largest size Francis hydro power turbine are still welded manually due to their unique and complex design, and the high-quality requirements. This paper presents an application of a Tungsten Inner Gas robot welding system for heavy multi-pass welding, what emphasizes the synergy of advanced CAD — CAM programming and human-in-the-loop control. The concept consists three separated phase: the off-line planning of the whole process, the plan update based on the previous activities, and the on-line welding operation. The proposed system was verified through experiments.

The installation of industrial robot systems requires considerable human effort both related to the mechanical and electromechanical setup. However, the task of programming a robot is of particular importance to satisfy given process requirements. Typically, only 20% of the entire programming time is needed to define the path and logics while the remaining 80% is related to process optimization. This causes considerable costs due to the need for human presence. With a remote assistance system and a process monitoring robot, expert assistance could be decoupled from the physical presence. An important challenge is to solve the tracking between the monitoring robot and the robot performing the process. In this paper we propose a controllable sensor system for enhanced process monitoring. The system is decoupled from the process tool and can therefore be controlled independently. It provides the machine operator with adaptive process information and enhances the capabilities to qualify complex processes. We apply the concept to an autonomous sensor robot monitoring an industrial robot system for heavy, multipass TIG welding of voluminous workpieces.

Recently industrial robot systems are introduced widely even in the small and medium size enterprises. However, it is difficult for them to employ professional engineers permanently. Then, they need to depend on outside to maintain industrial robots. Therefore a remote operation support system for industrial robots is proposed. Visual and auditory feedback is often used. However, a perception of the information might be limited if different kinds of information in particular sense modality is delivered at the same time. To solve the problem, we proposed a tactile interface which uses tactile information. This paper evaluates the usefulness of the vibrotactile information using the glove-type interface. The experimental results showed that vibrotactile information could not improve work efficiency. However it enable an operator to concentrate other information without increasing a workload. Therefore vibrotactile information is useful.

The trend in robotization is to use industrial robot more and more frequently in small and medium sized enterprises (SMEs). Wide spread of the enterprises over considerable area and small number of applied robot units per enterprise, emerges need to provide an efficient, inexpensive and immediate support remotely. Since there are a lot of important information to be communicated to efficiently support an industrial robot system, traditional data acquisition and human-machine-interfaces (HMI) cannot provide complete and effectively comprehended overview of the state of the robot cell. The goal of the paper is to demonstrate new methodology and technology for remote HMI based upon Cognitive Informatics Communication (CogInfoCom 2011) that augments efficiency of communication between an industrial robot system and remote operator exercising control over the system. For the purposes of evaluation a remote operating laboratory is developed. The laboratory consists of multimodal HMI interfacing an operator with physically separated seven axes NACHI MR20 robot. By means of multi-camera vision, multi-speaker sound system, and advanced 3D simulation, the robot is controlled remotely. The results show that HMI based upon CogInfoCom can be beneficially applied to communicate complex states of an industrial robot system to a remote operator.

This paper presents a robot control system using force control on a redundant industrial robot. The control system is based upon an active force feedback system using six axes force sensor attached to the robot's end effector. The redundancy is used to explore a model for singularity avoidance based on different states of redundancy. The system is implemented and tested experimentally for one of the described states on a NACHI MR20 seven axes robot. The experimental results demonstrate the possibility to control a redundant industrial robot by force control.

This paper presents an automated assembly and tack welding operation of high performance aerospace components using two real-time controlled industrial robots and a high-precision non-contact measurement system. The system was able to align two components with an offset distance less than 0.1 mm, well within manufacturing tolerances.

A system concept for industrial collision avoidance is presented. The paper searches solutions for small and medium enterprises which have strictly limited resources for robot installations. Key factor is to use commercially available components and user-friendly algorithms. The experimental setup consists of a 7-axis industrial robot and an industrial robot controller. The obstacle detecting sensors are applied on the robotic arm. Designing guidelines are formed according to industrial considerations and preliminary experiments are presented.

This paper evaluates a wristband-type tactile interface as a user interface for controlling an industrial robot remotely. When operating a remote monitoring system, information delivery from a local site to an operator at a remote site is important. Visual and auditory feedback is often used. However, perception of the information might be limited if different kinds of information in particular sense modality is delivered at the same time. To solve the problem, we proposed a tactile interface which uses tactile information and we evaluate it. First, we explain the remote operation system for industrial robot and interface, then after that, we present an experiment of vibrotactile information of industrial robot.

The global industry is developing towards smaller and smaller batch sizes in production due to the high pressure on Just-in-time production. This has led to the need for providing cost efficient support to robot users, especially SMEs having limited internal resources and competence to setup, maintain and reconfigure their industrial robot systems. In this study, a new method for the remote operation of industrial robot systems is presented. The method is based upon multi-modal man-machine communication and sensor bridging to transfer huge amounts of information from the industrial robot cell to the brain of the remote operator. The general methodology is explained, however, a special focus is put on gripping and stick-slip detecting in order to provide optimal grasping conditions during robot operations; especially during remote operation.

Development of the international industry is towards smaller and smaller batch sizes in the production. This has riced a need for cost efficient support of robot users. In this paper, new methodology for remote operation of industrial robot systems is introduced. The method is based upon multi-modal man-machine communication and sensor bridging to transfer the huge amount of information from the industrial robot cell to the brain of the remote operator.

This paper presents a control system for redundant robot manipulators that handles the path planning and redundancy control in two separate loops. The goal is to simplify industrial programming of redundant robots, by decomosing it to a familiar path planning loop, and an autonomous redundant control loop. The familiar path planning is done using an industrial robots native control system, which is already known to the operator. An external feedback loop acts as a secondary task control loop so that the redundancy in the robot is used automatically. The secondary task control is expanded from the null space projection method to a method where a parallel space to task space is modeled in joint space. The system was implemented and experimentally verified on a NACHI MR20 7-axes industrial robot with AX20 Controller. The secondary task in the experiments was an obstacle avoidance task that was tested in unknown dynamic and static environments.

Presents a robot control system dedicated to grinding large Francis turbines. The control system is based on an active force feedback system using a three‐axes force sensor attached to the robot’s end effector. This system offers high flexibility and robustness against workpiece positioning and grinding tool wear. It provides control of the grinding process parameters ensuring high productivity in addition to good grinding performance and grinding tool economy. The system was experimentally tested out on a MultiCraft 560 grinding robot.

In this paper the main focus is on the user interfaces available for robot controllers and how they comply with the requirements of flexibility. An overview is given of the most important robot manufacturers teach pendant interfaces. The conclusion is that the process of creating customized user interfaces is still complicated and the how-to is unclear. We introduce the concept of flexible user interface based on service oriented robot cell operation. In order to offer more user friendly solutions industrial robot systems should use human-centred approach. Service oriented robot cell operation creates an abstract level for human robot interaction which is adapted to human cognition. A flexible graphical user interface is the final link between the robot cell and the operator, which offers a solution for issues faced in creation of customized user interfaces by its flexibility. One implementation called FlexGui is described in details and the most important features are demonstrated in a case study.

Presents a robot control system dedicated for grinding and deburring robots. The control system is based on an active force feedback system using three axes force sensor attached to the robot’s end effector. This system offers new functionality in rapid programming of the robot by applying automatic programming and force supervision. The system is implemented and tested experimentally on a MultiCraft 560 robot with parallel kinematics. The experimental results show a significant reduction in the programming and set up time compared to conventional robot control systems.

An attempt is currently being made to widely introduce industrial robots to Small-Medium Enterprises (SMEs). Since the enterprises usually employ too small number of robot units to afford specialized departments for robot maintenance, they must be provided with inexpensive and immediate support remotely. This paper evaluates whether the support can be provided by means of Cognitive Info-communication – communication in which human cognitive capabilities are extended irrespectively of geographical distances. The evaluations are given with an aid of experimental system that consists of local and remote rooms, which are physically separated – a six-degree-of-freedom NACHI SH133-03 industrial robot is situated in the local room, while the operator, who supervises the robot by means of audio-visual Cognitive Human-Machine Interface, is situated in the remote room. The results of simple experiments show that Cognitive Info-communication is not only efficient mean to provide the support remotely, but is probably also a powerful tool to enhance interaction with any data-rich environment that require good conceptual understanding of system's state and careful attention management. Furthermore, the paper discusses data presentation and reduction methods for data-rich environments, as well as introduces the concepts of Naturally Acquired Data and Cognitive Human-Machine Interfaces.

A new programming method is developed for grinding robots. Instead of using the conventional jog-and-teach method, the workpiecc geometry is automatically scanned by a contour tracking system. During tracking of the workpiece contour, the robot position is continuously logged. Finally a robot program is automatically generated.