Abstract
The development and optimisation of compliant (or flexure-based) manipulators with redundant actuation have been considered before, showing that the redundancy can be exploited to increase the support stiffness and reduce actuator loads. However, so far only 2-DOF manipulators have been considered which enable translational motion in two directions. In this paper a third degree of freedom, the in-plane rotation of the end effector, is added. The goal is to design and evaluate a first prototype capable of full planar motion. The dynamic performance of the manipulator is analysed with a flexible multibody model. The links are assumed to be rigid. The SPACAR software is used as its flexible beam element can describe the non-linear behaviour of the flexure joints well at rather large deflections and accounts for constraint warping. In this prototype the end effector range of motion is limited such that the joint rotations do not exceed ±30 deg. Butterfly and cartwheel flexure joints can handle the specifications without violating stress constraints. In the final design the lowest natural frequencies are 3.6 Hz for both translations and 7.9 Hz for the rotation. The first parasitic frequency is expected at 76 Hz, which is sufficiently high. This prototype has been manufactured with 3D printing. The lowest translational frequencies appear to be somewhat higher than expected, which could arise from stiffness added by the flexible coupling between actuator and upper arm. A higher resonance frequency is found near 80 Hz, which agrees well with the expected first relevant parasitic mode.
Original language | English |
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Title of host publication | Proceedings of the11th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS |
Place of Publication | Lisbon |
Publisher | Instituto Superior Técnico Lisbon |
Number of pages | 10 |
Publication status | Accepted/In press - 30 Mar 2023 |
Event | 11th ECCOMAS Thematic Conference on Multibody Dynamics 2023 - Instituto Superior Técnico (IST) Congress Center , Lisbon, Portugal Duration: 24 Jul 2023 → 28 Jul 2023 Conference number: 11 https://multibody2023.tecnico.ulisboa.pt/ |
Conference
Conference | 11th ECCOMAS Thematic Conference on Multibody Dynamics 2023 |
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Country/Territory | Portugal |
City | Lisbon |
Period | 24/07/23 → 28/07/23 |
Internet address |
Keywords
- Flexure-based mechanisms
- Redundantly actuated parallel kinematic manipulator (PKM)
- Non-linear beam elements
- Experimental system identification