Pajako: Stiffness optimization of functionally extended Delta robots

  Delta-Robot with three Arms Copyright: © IGMR


Photo of Christian Mirz © Copyright: IGMR


+49 241 80-99804



Project State



The increasingly high degree of industrial automation has led to growing demands for efficient and sustainable robotic systems. While the power consumption of a single system is comparatively low, large scale production with thousands of robots places considerable demands. In this context, green and efficient production systems have become an important sales argument for modern industries in recent years. In this context, the reduction of peak power requirements is of great importance.

Highly dynamic handling tasks require a high payload/weight ratio, high positioning accuracy and excellent stiffness properties. Parallel manipulators meet these requirements due to their special architecture with frame-side drives and thus low moving masses. Delta robots are the most widely used manipulators for high-speed pick-and-place applications. This poses new challenges for the development process. Accordingly, kinematic and dynamic analyses are confronted with demanding models of functionally extended variants. The increased complexity is reflected in computationally intensive modelling approaches. Consequently, efficient modelling techniques are required to predict system behaviour and finally to form the basis for a holistic task-oriented dimension synthesis.

The basis for such a dimensional synthesis was laid in a previous project, in cooperation with the Mechanical Systems Design Laboratory of the Tokyo Institute of Technology ("Performance Enhancement of Functionally Enhanced Delta Robots", funded by the DAAD), with the development of a dimensional synthesis based on kinematic and dynamic evaluation criteria. It was shown, that such combined approaches are particularly advantageous for industry-relevant delta robots that have been extended by serial chains. In addition, the consideration of dynamic properties and suitable evaluation criteria (such as energy consumption and maximum performance) takes into account the growing requirements for energy-efficient and sustainable production.

The optimization of the dynamic properties of a system (tends to) go hand in hand with a reduction of masses and thus a deterioration of the stiffness properties. Therefore, the aim of this project is to integrate the stiffness properties into the design optimization/dimensional synthesis process. Accordingly, the elasticities of the individual robot components are modelled and used to describe and optimise the overall stiffness of the robot using an analytical stiffness model. Finally, this model is combined with the existing dimensional synthesis based on kinematic and dynamic evaluation criteria to achieve a holistic optimization of the robot.

The research on this project is conducted in close cooperation with the Mechanical Systems Design Laboratory of the Tokyo Institute of Technology and mutual exchange of scientific staff and students.



Mechanical Systems Design Laboratory, Tokyo Institute of Technology, Japan


PAJAKO, DAAD: Deutscher Akademischer Austauschdienst e. V