Off-line Robot Programming Research Articles

Creating Digital Twins of Robotic Stations Using a Laser Tracker

This article deals with the design and creation of digital twins of robotic stations. A literature review of digital twins, robot programming methods and laser tracker applications is presented. This paper shows that the construction of digital twins is closely related to one of the most popular methods of robot programming, i.e., off-line programming. In the case of digital twins of robotic stations, modeling accuracy and two-way communication with the real station proved to be crucial. The article proposes a methodology for solving the basic problem of off-line robot programming, i.e., the limited accuracy of the representation of the station and the details. The algorithm of proceeding in the case when the station already exists and its digital model is built and the case when the digital model is first created and the real solution is built on its basis is shown. According to the developed methodology, a digital twin of a real robotic station was created and the possibilities arising from the use of virtual tools were shown. The developed digital twin has the ability to communicate with advanced Matlab 2021-type tools, uses cloud solutions and virtual and augmented reality for training, simulates physical phenomena and provides the ability to accurately program robots off-line.

Offline robot programming assisted by task demonstration: an AutomationML interoperable solution for glass adhesive application and welding

ABSTRACT Robots have been successfully deployed in both traditional and novel manufacturing processes. However, they are still difficult to program by non-experts, which limits their accessibility to a wider range of potential users. Programming robots requires expertise in both robotics and the specific manufacturing process in which they are applied. Robot programs created offline often lack parameters that represent relevant manufacturing skills when executing a specific task. These skills encompass aspects like robot orientation and velocity. This paper introduces an intuitive robot programming system designed to capture manufacturing skills from task demonstrations performed by skilled workers. Demonstration data, including orientations and velocities of the working paths, are acquired using a magnetic tracking system fixed to the tools used by the worker. Positional data are extracted from CAD/CAM. Robot path poses are transformed into Cartesian space and validated in simulation, subsequently leading to the generation of robot programs. PathML, an AutomationML-based syntax, integrates robot and manufacturing data across the heterogeneous elements and stages of the manufacturing systems considered. Experiments conducted on the glass adhesive application and welding processes showcased the intuitive nature of the system, with path errors falling within the functional tolerance range.

User Study to Validate the Performance of an Offline Robot Programming Method That Enables Robot-Independent Kinesthetic Instruction through the Use of Augmented Reality and Motion Capturing

The paper presents a novel offline programming (OLP) method based on programming by demonstration (PbD), which has been validated through user study. PbD is a programming method that involves physical interaction with robots, and kinesthetic teaching (KT) is a commonly used online programming method in industry. However, online programming methods consume significant robot resources, limiting the speed advantages of PbD and emphasizing the need for an offline approach. The method presented here, based on KT, uses a virtual representation instead of a physical robot, allowing independent programming regardless of the working environment. It employs haptic input devices to teach a simulated robot in augmented reality and uses automatic path planning. A benchmarking test was conducted to standardize equipment, procedures, and evaluation techniques to compare different PbD approaches. The results indicate a 47% decrease in programming time when compared to traditional KT methods in established industrial systems. Although the accuracy is not yet at the level of industrial systems, users have shown rapid improvement, confirming the learnability of the system. User feedback on the perceived workload and the ease of use was positive. In conclusion, this method has potential for industrial use due to its learnability, reduction in robot downtime, and applicability across different robot sizes and types.

The Use of Virtual Twins in the Robotic Yoghurt Mixing Process

This paper presents the results of computer simulations related to the selection and optimisation of parameters for a robotic yoghurt mixing process. The authors proposed a station configuration using the RobotStudio environment for off-line robot programming and virtual controller technology and determined the performance of the robotised production line. The main component of the study was a computer simulation of the station based on the Picking PowerPac package and Pick Master 3 program. As a result of the simulations, numerical values were obtained informing about the number of handled and rejected products, filled containers and the times of production cycles of the station.

ドロネー単体分割を利用した位置決め誤差補正手法と大型成形機への適用

Recently digital twins are widely utilized in various manufacturing stages. Robot off-line programming, a typical example of manufacturing digital twin, have been used for over 20 years in actual factory shops, and various methods are proposed to compensate the error between digital model and real world. This paper discusses the error compensation methods for various types of mechanical errors, and proposes a new method which can compensate positional errors of any points based on a certain number of measured points using Delaunay Triangulation. We applied this method to a large-sized forming machine and show that this method can reduce the positional error to less than half.

Overview of some Command Modes for Human-Robot Interaction Systems

Interaction and command modes as well as their combination are essential features of modern and futuristic robotic systems interacting with human beings in various dynamical environments. This paper presents a synthetic overview concerning the most command modes used in Human-Robot Interaction Systems (HRIS). It includes the first historical command modes which are namely tele-manipulation, off-line robot programming, and traditional elementary teaching by demonstration. It then introduces the most recent command modes which have been fostered later on by the use of artificial intelligence techniques implemented on more powerful computers. In this context, we will consider specifically the following modes: interactive programming based on the graphical-user-interfaces, voice-based, pointing-on-image-based, gesture-based, and finally brain-based commands.

Utilization of OLP method in the analysis of a robotic 3d scanning process

In the paper the assessment of the feasibility of using a selected off-line robot programming environment in the design process of a robotic 3D scanning process was presented. First of all, basic information about modern industrial robots implementations were outlined. Secondly, a developed virtual model of an analyzed robotic cell was described. Moreover, analyses on selected aspects of the considered issue were discussed. The study has confirmed that utilization of OLP method is very useful and needed for improvement of robotic production processes.

Off-line programming of robot on laser cleaning for large complex components

Laser cleaning path planning is great for significance to the cleaning effect of component surface. In view of the fact that the cleaning head must keep a fixed focal length with the workpiece surface and keep a vertical angle with the workpiece surface at all times in the laser cleaning process, this paper introduces the numerical model of large components into the general off-line programming software, and according to the relevant laser cleaning process and setting specific parameters in the software, obtains the automatically planned machine. The human trajectory program is introduced into the robot to realize the surface cleaning of large and complex components. Finally, according to the actual cleaning effect in the field, the laser focal length deviation is controlled within ± 2mm, and the application of off-line programming of industrial robots in complex surfaces is summarized and prospected.

Towards a CAD-based Automated Robot Offline-Programming Approach for Disassembly

Currently, programming a robot is time-consuming both online and offline. To address this challenge, a novel approach is applied to generate the robot program of an industrial robot automatically. Robot program blocks are generated based on disassembly information from the CAD product model and the product model itself. For this purpose, the robot manufacturer-independent robot offline programming software "Octopuz" is used. Furthermore, the focus of the presented approach is on the two fundamental process types, "pick & place" and "unscrewing", to validate the feasibility of the proposed method.

Autonomous Off-line robot programming for powder suction operation with PythonOCC

1. KOHR C.T., STAMP R., PIPE A.G., KIELY J., SCHIEDERMEIER G., 2013, An Online Robot Trajectory Planning and Programming Support System for Industrial Use, Robot. Comput. Integr. Manuf., 29/1, 71–79, Feb., DOI: 10.1016/j.rcim.2012.07.010. CrossRef Google Scholar

Offline programming method and implementation of industrial robot grinding based on VTK

Purpose The purpose of this paper is to present a robotic off-line programming method for freeform surface grinding based on visualization toolkit (VTK). Nowadays, manual grinding and traditional robot on-line programming are difficult to ensure the surface grinding accuracy, thus off-line programming is gradually used in grinding, however, several problems are needed to be resolved which include: off-programming environment depends on the third-party CAD software, leads to insufficient self-development flexibility; single support for robot type or workpiece model format contributes to lack of versatility; grinding point data depends on external data calculation and import process, causes human-computer interaction deterioration. Design/methodology/approach In this method, the visualization pipeline and observer/command mode of VTK are used to display the 3D model of the robot grinding system and pick up the workpiece surfaces to be grinded respectively. Two groups of cutter planes with equidistant spacing are created to form the grinding nodes on the surface, and the extraction method for the position and posture of the nodes is proposed. Furthermore, the position and posture of discretized points along the grinding curve are obtained by B-spline curve interpolation and quaternion spherical linear interpolation respectively. Finally, the motion simulation is realized by robot inverse kinematics. Findings Through a watch case grinding experiment, the results show that the proposed method based on VTK can achieving high precision grinding effect, which is obviously better than traditional method. Originality/value The proposed method is universal which does not depend on the specific forms of surface, and all calculations in simulation are completed within the system, avoiding tedious external data calculation and import process. The grinding trajectory can be generated only by the mouse picking operation without relying on the other third-party CAD software.

Research on off-line programming method of spatial intersection curve welding based on VTK

Robot off-line programming is widely used in the field of spatial intersection curve welding. However, several existing problems are needed to be resolved which include the following: the operation process depends on the third-party CAD software, the welding trajectory planning depends on the precise analytical formula, and the determination of welding posture lacks fusion of geometrical features of surrounding surfaces. This paper presents an off-line programming method of spatial intersection curve welding based on visualization toolkit (VTK). In this method, the visualization pipeline and observer/command mode of VTK are used to display the 3D model of the robot welding system and pick up the surfaces around the welding seam respectively. By calculating the normal vectors of the picked surfaces, the equidistant cutter planes perpendicular to these surfaces can be automatically created to form the planning weld nodes on the intersection of the surfaces, and the position and posture of the welding torch on weld nodes can be extracted. Furthermore, the position and posture along the weld curve are discretized by B-spline curve interpolation and quaternion spherical linear interpolation, respectively. Finally, the motion simulation is realized by the application of robot inverse kinematics. This method does not depend on the specific form of intersection, and all calculation processes are completed within the system, avoiding tedious external data calculation and import process. The correctness and practicability of the method are verified by the welding experiment of saddle-shaped cylindrical intersection pipes.

A new approach to simulate coating thickness in cold spray

In the process of cold spray on complex components, the coating thickness is an important indicator to monitor and control. Current methods such as destructive tests or direct mechanical measurements can only be performed after spraying. Besides, these methods lead to production shutdown and additional costs . This article presents a novel approach predicting coating thickness for components with complex curved surfaces, especially in the case of shadow effects. Firstly, a three-dimensional geometric model of the coating profile based on Gaussian distribution was developed. In addition, the relative deposition efficiency (RDE) resulting from the different robot kinematic parameters was illustrated in detail. Secondly, this model was coupled with robotic trajectories and processing parameters to simulate coating deposition in robotic off-line programming software. Finally, the coating morphologies as well as the predicted coating thickness were presented in a graphical virtual environment. According to the results of the simulation, the robot trajectory, operating parameters and spray strategy can be adjusted with iteration in the feedback loop to achieve the desired coating thickness distribution. Both numerical and experimental verifications were carried out in the end of this study. The results show that this proposed method has a reliable prediction accuracy for practice.

A robot off-line programming system for welding intersecting pipe

In order to meet the requirements of welding intersecting line welds, an off-line programming system is designed. The off-line programming system is developed with SolidWorks API functions, includes kinematics analysis, trajectory planning, off-line simulation and other modules. The system is applied to an ABB welding robot with six revolute joints. The welding experiment of the robot cylindrical intersecting pipe is carried out, and the experimental results verify the system.

Study of inter-operational breaks impact on materials flow in flexible manufacturing system

Present development of advanced technologies in production and logistics, orientation for a customer needs and global, competitive market determines a creation of flexible manufacturing systems. Each FMS consisting of the automated and robotized subsystems of production, assembly, inter-operational transport and storage should be treated as a complete logistics system in which the efficient flow of materials is realized, at every stage of processing. The efficiency of the system is based on possibility of quick, automated retooling and reprogramming for the manufacturing of new products, especially in the production for individual order. Except that, according to modern concepts of enterprise management, one of the factors to improve material flow is to minimize unnecessary inter-operative interruptions. The inter-operational breaks include many factors: handling and transport, waiting for a technological operation and assembly, quality control, unpredictable failures. While technological times are almost impossible to shorten, all issues related with logistics are possible to improve. The inter-operational breaks don’t create added value, they’re only waste. They often remain outside the research sphere or are treated marginally as a loss included in the manufacturing process. The article describes study on an effective method of searching for negative inter-operational breaks in advanced manufacturing processes and eliminating them. Advanced software for off-line programming of machine tools, robots, automated transport and warehouse systems and general-purpose simulation software for production and logistics gives possibility to conduct research on limiting the impact of inter-operational breaks on FMS.

The virtual commissioning technology applied in the design process of a flexible automation system

This paper describes an application of the virtual commissioning technology applied to the design of a robotized manufacturing cell. Virtual commissioning requires the integration of different technologies, such as PLC (programmable logic controller) programming, device communication with OPC (OLE for process control), off-line robot programming, HIL (hardware-in-the-loop), as well as the design of devices and tools using computer-aided design (CAD) applications. Within this application, the virtual commissioning resource evaluates the operation of an assembly line, simulates several processes in a digital environment, tests real equipment and tools and integrates a system that shares the signals of the sensors and actuators with the simulation environment in the computer. The case study described herein compares a conventional design process of a car floor spot welding station to the design approach using virtual commissioning. The robotic welding cell is controlled by a PLC integrated in a simulation environment that uses two industrial robots created in the Process Simulate Robotics application of Siemens Tecnomatix®.

Using Virtual Reality as a Support Tool for the Offline Robot Programming

Abstract The present article focuses on the possibilities of using Virtual Reality (VR) as a supporting tool by using the offline programming method for industrial robots. The philosophy of using such a process is hierarchically linked to the observance of methodological procedures for the proposal new workstations with using industrial robots. First, it is necessary to develop CAD models of the projected workplace, which can be imported into a suitable simulation environment for the creation of robotic simulations with support for visualization to the immersive VR environment. In our case, the CAD software Catia was used to develop a workstation, followed by integration of the CAD database into the simulation environment of Process Simulate (PS). Support for the visualization in the immersive environment of the Virtual Reality of Process Simulate was vested using the glasses headset HTC VIVE.

Off-line scan path planning for robotic NDT

This work presents computer-aided scan path generation for robotic non-destructive testing of complex shaped test-pieces. Off-line programmed scan path was used to robotically inspect an aluminium fixed leading edge skin panel of an aircraft wing by means of swept frequency eddy currents method. Eddy currents probe was deployed by means of a six-axis robotic arm KUKA KR5 arc. Reverse engineering of the test-piece was carried out to reconstruct CAD model of its surface. Positioning accuracy of the performed continuous scan was measured with a laser tracker in accordance with ISO 9283:1998 and is reported in the paper. The positional uncertainty of the NDT scan calculated as the standard deviation of the measured path coordinates from the command path coordinates does not exceed 0.5 mm which is rather moderate taking in account uncertainties associated with the off-line robot programming.

Survey on Human-Robot Interaction for Robot Programming in Industrial Applications

The recent trends in modern industry highlight an increasing use of robots for a wide range of applications, which span from established manufacturing operations to novel tasks characterized by a close collaboration with the operators. Although human-robot collaboration allows to relieve operators of exhausting works, an effective collaboration requires a straightforward interaction to foster the use of robot assistants. This paper provides a comprehensive survey on human-robot interaction approaches and related interfaces addressed to robot programming. An overview of on-line and off-line robot programming techniques is first presented. Then, novel intuitive interaction means, such as those based on multi-modal interaction, virtual and augmented reality, are considered. The paper aims at pointing out that collaborative robotics can effectively reduce operator’s physical workload if easy to use interfaces for robot programming are provided.

The Design of General Off-Line Graphical Robot Programming System

The Design of General Off-Line Graphical Robot Programming System