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Virtual Prototyping of Tool Machines with Force Feedback
Partners in this project
- Laboratory for Machine Tools (WZL), Aachen University
Prof. Manfred Weck - Center for Computing and Communication (CCC), Aachen University, Virtual Reality group
Dr. Torsten Kuhlen
Status
Finished in 2000
Project description
The synergy between the fields of Robotics and Virtual Reality has extensively been documented in the literature of the 90's. While most of the work concentrates on applications in robot programming, plant layout simulation and teleoperation, our project is about the use of VR technology in the design process of innovative robot kinematics and tool machines. The innovative aspects of our approach comprise the integration of force feedback into the interaction and the possibility to modify a robot configuration from within the virtual environment.
Until today, CAD software is often used for the development of tool machines. However, although the modeling of a robot by means of a CAD tool can give a first impression on the characteristics and capabilities of the kinematics, it cannot give the engineers an intuitive assessment of the robot's behavior. As a consequence, the development of a new tool machine involves the creation of numerous prototypes, algineer to validate the kinematics and physical behavior of the robot. However, it is a well-known fact, that physical prototyping is a time-consuming and therefore cost-intensive task. Furthermore, physical prototypes are inflexible in the sense that the modification of an already built model is nearly impossible.
Motivated by the activities of the automotive industry, which has been successfully experimenting with Virtual Prototyping during the recent years, we therefore propose to replace most of the physical prototypes of tool machines by virtual prototypes in the robot design process in order to reduce time and costs.
We are developing a software package that allows an engineer to interactively explore a robot prototype in a virtual environment. The software is based on the platform-independent ViSTA (Virtual Reality Software University of Technology Aachen). To get an intuitive feeling of the virtual robot characteristics, 3-D interaction techniques and immersive projection technologies should be integrated. In ViSTA, the virtual prototypes can be alternatively visualized in a CAVE or on a (dual) Workbench. Typically, the engineer wants to move the robot's end effector in the working volume. In our software, real-time inverse kinematics in combination with direct interaction using a 3-D tracked mouse give the impression that we grasp the tool center point just like that of a real prototype. The sensation of reality can be dramatically improved by using force feedback techniques. Appropriate forces are generated when the robot's tool center point reaches the border of the working volume or when collisions between robot segments occur. In ViSTA, a PHANToM Haptic Device has been integrated to transfer the calculated forces to the user.
The tool macines we are working on are innovative in the sense that they are based on parallel kinematics. The Hexapod for example, consists of a fixed frame that joins six handles whose length can be varied in order to steer the tool center point in the middle of the machine. This construction allows a much more precise operation in comparison to traditional robot arms. Our software not only allows an interactive exploration of the kinematics for a given Hexapod configuration, but it also enables the engineer to modify the joint arrangement in order to find an optimal configuration for a required manipulation task. The engineer is supported by guiding cycles when she wants to modify the configuration.
Videos
- Interactive exploration of the Hexapod with force feedback Download (9 MB) or Streaming
- Interactive configuration of the Hexapod Download (10 MB) or Streaming
- Part of an interview with T. Kuhlen in WDR television Download (20 MB) or Streaming
Gallery
| Physical prototype | CAD model | Interactive exploration of the Hexapod |
| | Interactive modification of the Hexapod configuration from within the virtual environment | |
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