Robotic system uses camera control to achieve absolute precision

Citation

(1998), "Robotic system uses camera control to achieve absolute precision", Industrial Robot, Vol. 25 No. 5. https://doi.org/10.1108/ir.1998.04925eaf.005

Robotic system uses camera control to achieve absolute precision

Robotic system uses camera control to achieve absolute precision

Keywords Camera industry, Neos Robotics, Robotics

Significant savings are possible when machining bulky work pieces by working to great precision. According to Neos Robotics of Sweden this capability is offered by a combination of a robot and a photogrammetric measurement and control system. There is no need to construct expensive jigs and fixtures, and error tolerances owing to material expansion are eliminated. The new method is called TI² (see Plate 2), derived from its three component parts; the Tricept robot, the Imetric measuring system and the Igrip simulation program, and is based on Swedish-Finnish-Swiss co-operation.

TI² is a system that offers genuine flexibility in manufacturing large, bulky work pieces. The system includes the Tricept robot from Neos Robotics, the Imetric camera measurement system from Switzerland, and a Finnish Tehdasmallit's computer simulation program. The robot's tool head is adjusted to align with the actual position of the work piece, taking into account ambient temperature, heating from the machining processes, changes in the work piece shape and position, etc. Measurement points applied to the work piece are identified and read by a CCD camera system, and compared with the correct dimensional values in the CAD file from the drawing office. This is turn forms the basis for steering and positioning the robot's manipulation head in precisely the correct position, duly compensated and corrected for the current actual dimensions of the work piece.

Plate 2 The TI² robot C: Neos Robotics AB

The TI² concept can broadly be divided into four constituent parts; the Tricept robot, a positioning camera system, a control and regulation unit and a supervisory camera system.

The Tricept industrial robot from Neos Robotics is the manipulative part of the TI² system, and its tool holder can be equipped with a variety of tools for drilling, milling, riveting, gluing, assembling and so on.

Put simply, the camera system can be said to be the eyes the system uses to ensure correct location of the work piece, regardless of its position, while the software regulating the robot simulation and control movements forms the link between the CAD model and the real, actual conditions on the work bench. All this is carried out in real time and is immediately applicable during the machining process.

Many application areas

The TI² system is ideally suited to such machining tasks as drilling and milling of, for example, truck chassis with individual variants of the drilling hole patterns and riveting of large components, or to limited series production of aircraft wings. The same applies to all applications where precision is required over large machining areas which may tend to distort during the machining process.

Aircraft industry first

The great potential of the TI² system has attracted the attention of the American aircraft manufacturer Boeing, which has negotiated for the first robot cell. Responsible for this agreement is purchasing manager Sandy S. Cunningham: "This new technology has great potential within our manufacturing group, and production technicians are now coming from our civil and military facilities all over the USA to study it."

Tricept facts

This robot has six degrees of freedom and can achieve a press power of as much as 15,000 N (1.5 tons) vertically and 3,500 N (0.35 tons) horizontally. Its ballscrew-driven triangle concept boasts a movement precision of +/­0.20mm, with a repetitive accuracy of +/­ 0.02mm, at a point-to-point speed of 1.0m/s.

For further information, please contact: Neos Robotics AB, VD Karl-Erik Neumann, Ritarslingan 22A, S-187 61 Täby, Sweden. Tel + 46 8 630 03 75; Fax: + 46 8 630 03 79; Mobile: + 46 70 568 08 20; E-mail: