Jan Wrege

Aspects on design of high precision parallel robots

This paper presents a concept for a micro‐assembly station and shows different possibilities for increasing the positioning accuracy. The main part of the station consists of a spatial parallel structure with three translational degrees of freedom. An additional rotational axis is integrated into the working platform. This structure is constructed with low friction joints, which are nearly free of backlash. The construction of these high precision joints is presented and the characteristics of the robot such as workspace and resolution are discussed. After this an approach for increasing the accuracy of parallel robots by integrating flexure hinges into the structure is described.

PARVUS – miniaturised robot for improved flexibility in micro production

Purpose – Until now, the size range of most machines for precision assembly was much larger than the size of the pieces to be handled or the necessary workspace. Flexibly scalable miniaturised production machines can help to develop much more flexible micro production systems. The paper aims to describe the development of a micro‐parallel‐SCARA robot adapted in size to MEMS products.Design/methodology/approach – The robot consists of a miniaturised parallel structure, which provides a high level of accuracy in a workspace of 60 × 45 × 20 mm3. It has a base area of 130 × 170 mm2 and offers four degrees of freedom.Findings – Based on simulations, the degree of miniaturisation in terms of a smaller structure and a high level of accuracy is determined. The results show that a miniaturised hybrid robot with a plane parallel structure driven by miniaturised zero‐backlash gears and electric motors can reach a theoretical repeatability better than 1 μm.Research limitations/implications – The first prototype provi...

Compliant Parallel Robots

In this paper the development of a macro parallel robot is presented in which conventional bearings are replaced by pseudo-elastic flexure hinges. The robot consists of a spatial parallel structure with three translational degrees of freedom and is driven by three linear direct drives. The structure has been optimized with respect to workspace and transmission ratio. Additionally, in simulations with the FEA tool ANSYS different geometrical arrangements and combinations of flexure hinges have been investigated with respect to the dynamic behavior of the compliant mechanism. Due to the symmetrical character of the structure and the optimized design of the combined flexure hinges the structure is very stiff. The experimental measured repeatability of the compliant robot is below 0.3 µrn.

“Parvus” a Micro-Parallel-Scara Robot for Desktop Assembly Lines

The paper describes the development of a micro-parallel-SCARA robot adapted in size to MEMS products. The degree of miniaturization is optimized concerning a smaller structure but high accuracy in a workspace dimensioned to chip card size. The robot supports the mostly used four degrees of freedom with a base area of less than 150 × 150 mm2. It is the result of a cooperative project between the Institute of Machine Tools and Production Technology at the Technical University of Braunschweig and Micromotion GmbH. This company is an innovative manufacturer of miniaturized zero-backlash gears and actors, which are used as main drives of the robot.

Sensor Guided Micro Assembly by Using Laser-Scanning Technology

To recognize geometric objects of components in assembly processes, in particular of microelectronic or micro system components, nowadays the use of vision systems is preferred. These systems are working very fast but the results depend on ambient conditions, especially of light settings. They deliver 2D object information referring to the image plane of a camera. In most sensor guided assembly systems, additional to vision systems laser displacement sensors are implemented to get information about the third dimension, the components height. In this paper a scanning method is presented which enables object recognition by using a laser positioning sensor and to use the achieved measuring values for a sensor guided assembly process.

High Precision Compliant Parallel Robot With an Optimized Large Workspace

In this paper a macro parallel robot is presented in which conventional bearings are replaced by pseudo-elastic flexure hinges. The robot consists of a spatial parallel structure with three translational degrees of freedom and is driven by three linear direct drives. The structure has been optimized with respect to workspace and transmission ratio. Additionally, in simulations with the FEM tool ANSYS different geometrical arrangements and combinations of flexure hinges have been investigated with respect to the dynamic behavior of the compliant mechanism. Due to the symmetrical character of the structure and the optimized design of the combined flexure hinges the structure is very stiff. The experimental measured repeatability of the compliant robot is below 0.3 μm.Copyright