Topology optimization of the compliant underactuated finger with the focus on out-of-plane stiffness

Topology optimization of the compliant underactuated finger with the focus on out-of-plane stiffness

Goemans, V.Y.

Herder, J.L. (mentor)

Mechanical, Maritime and Materials Engineering

BioMechanical Engineering

BMD

2013-06-27

For large-displacement mechanisms, such as underactuated fingers, the out-of-plane stiffness can pose problems, especially as it tends to vary over the in-plane range of motion. In this paper a method is presented to design compliant underactuated fingers using topology optimization with a focus on obtaining a desired out-of-plane stiffness profile. Load path representation is used in combination with a non-dominated sorting genetic algorithm. Aside from the thickness of beam elements, the curve of a beam element is also employed as design variable. A set of objective functions is used to evaluate the behavior of the out-of-plane stiffness over the range of motion. The resulting Pareto solutions provide insight into the trade-off between the different objective functions on contact force and out-of-plane stiffness and also show the capability of this method to design compliant underactuated fingers. Using objective functions on out-of-plane stiffness results in solutions with a higher out-of-plane stiffness than when these objective functions were not used, while the solutions decrease little in performance in terms of contact force. The resulting shape of the out-of-plane stiffness over the in-plane range of motion is shown to vary per solution. It is also shown that using curved beam elements can have a positive effect on the out-of-plane stiffness. Experiments on an underactuated finger prototype verified the simulation results.

topology optimization
compliance
underactuated
finger
out-of-plane stiffness
load path representation

http://resolver.tudelft.nl/uuid:18461370-a513-4448-9adf-fbbaeaa572fd

Student theses

master thesis

(c) 2013 Goemans, V.Y.