A graphical simulation tool with off-line robot programming

A robotic simulation and off-line programming package has been developed for use on Silicon Graphics workstations that has the capability of using several types commercially available virtual reality (VR) hardware devices. The software includes a library of 4, 5, and 6 degree-of-freedom (DOF) industrial robots with closed form inverse kinematics and translators that convert graphical simulation commands into the device control language that can be transferred to the robot control hardware. Forward kinematics, inverse kinematics, and joint space path planning methods used in the software development are discussed. The performance of three types of commercially available 6-DOF input devices are compared for use in interactive off-line programming. Stereo vision and external 6-DOF positioning devices were added to enhance programming efficiency and offer more realistic access to the virtual workcell environment.

The use of industrial robots for welding automation is a major and expanding applications area. In a welding task, the robot should smoothly trace along the weldseam with appropriate tool poses. For welding a complex 3-D curve, a large number of points should be taught to make the weld path smooth. This is a very tedious job and is not an easy way to leach the robot. In this paper, the requirements of a CAD system to be used as a robotic off-line arc-welding programming system are discussed. An off-line programming system for such application was developed. The workpieces and the weldseam were represented by analytical geometries. The positions and orientations of the weldgun along the trajectory were analysed by the task requirement of the welding procedure and solved by differential geometry. Calibration process was discussed to ensure programs were properly executed. This system is especially useful for off-line programming for the welding of complex 3-D curves.

The work described in this paper address the problems of productivity of Grohe's Portugal grinding/ polishing department, related to the frequent stops of robotic cells for on-line programming and program adjustments. The solution to the stated problem was achieved through the adoption of off-line programming as an alternative to the conventional on-line method. Efforts were developed to overcome some limitations and restrictions found in terms of the software applications used, in order to adapt and improve their use to the needs of this type of contact applications. The solution developed is currently used for off-line programming the grinding robots at Grohe Portugal, with a significant reduction in the cells stop time to program the robots and also in the cycle time. The application of the off-line programming method and of the new programming techniques allowed to obtain a reduction of the cell stop time (up to 85% reduction), to optimize the production cycle time (up to 10% reduction) and, simultaneously, good results in terms of product finishing. The main limitations faced are the lack of realism of the wheel flexibility and the lack of sensitivity of the contact force with it.

Examines the developing uses of off‐line programming (OLP) in the automotive industry, particularly in the areas of robot welding and robot painting of vehicle bodies. States that this is due to the development of graphical simulation tools and outlines their role in “right first time” policies. Looks at applications of OLP at Volvo, Capponi Alesina (Fiat’s largest, painting subcontractor) and Applied Manufacturing Technologies, a US manufacturing systems design house. Describes the use of OLP in painting machines and truck painting, and in spot welding truck bodies.

In this paper, the path planning method of a redundant robotic work cell consisting of an overhead linear rail and a FANUC 6-joint robot mounted on it is studied for the continuous-trajectory tracking task. The existence of the solution of the inverse kinematics problem of the rail-mounted industrial robot (RMIR) is discussed and an analytical redundancy resolution scheme for RMIR is proposed based on the workspace. The path planning method with the performance evaluation mechanism makes the end-effector (EE) of robot reach the target position and posture and avoid joint limit, which makes the best of the redundant degree of freedom to improve the robot performance. The results of simulation and experiment prove that the proposed method is effective in the application of the long and closed-trajectory tracking. The above research findings are integrated into the robot off-line programming (OLP) software developed based on the UG platform and successfully applied to the robotic induction hardening for the chamfers of the large automobile panel dies.

We consider a modeling language and a simulation environment based on object- oriented principles and aimed to help in the design of reactive systems. The language framework includes diagrams of object structure and interconnection, statecharts as a behavior description, and C++ for data objects and functions. Timed Transition Systems are used as a semantical model. COVERS enables the user to perform the whole modeling-simulation-analysis cycle within a single MS Windows-based graphical environment. We overview the code generation, model execution and visualization of results. The correspondence between COVERS language and the Unified notation is outlined.

16 - Collagen hydrogel-based scaffolds for vascular tissue regeneration: Mechanical and viscoelastic characterization

In typical robotic sheet metal bending process, unloading of sheet metal parts is a challenging task due to complex nature of three-dimensional part geometry, and it is not possible to place the parts on a flat table. Hence, there is a need to design proper unloading station that allows the robotic gripper to unload the part with stability and without any collision. For this purpose, this paper proposes configuration of unloading station with a perforated table with a specific pattern of holes in which cylindrical pins are inserted. Then, a CAM system with a heuristic algorithm, along with a graphical interface, is developed to identify the number and distribution of pins on a perforated table that supports the part in a stable manner. The results are validated, for a variety of complex-shaped parts, using a graphical simulation tool.

Off-line programming of spot-weld robot is the future application of robotics. It could develop robot programs without the access to the robot itself and reduce the programming time required for the manufacturing process. In this paper, an approach to implement the off-line programming of robot based on Robcad with the process knowledge of car-body in White welding was proposed. Some common problems, such as motion simulation, collision detection and calibration can be solved by this approach. Finally, the off-line programming of spot-welding robots for a car's welding work-station was realized.

The general requirements of a robot simulation system are discussed and the benefits of integrating such a system with a solid modeller are indicated. The status of a robot simulator integrated with the BUILD solid modelling system is examined. The application example cited is the Condition Number analysis for optimum positioning of a workpiece in a robot's workspace. The robot simulator is used to verify that no interference takes place between the robot and workpiece in the optimum position.

ロボットのオフラインプログラミング

Off-line programming of robots will become increasingly more important. This paper describes a robot programming system which is based upon the use of geometrical constraints on the degrees of freedom of a component for specifying robotic assembly actions. Two pieces of software have been developed which allow easy definition of these constraints and the order of execution of the constraints.

Research Tends in the Off-Line Programming of Robots

A novel TCF calibration method for robotic visual measurement system

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.