Vibration Analysis of a Soft Hydrodynamic Manipulator

Abstract

In modern times, industrial automation has made significant progress by reducing human labour and speeding up manufacturing processes. However, limitations in traditional manipulators have led to restricted workspaces and time-consuming repetitive tasks, making the implementation of flexible manipulators with increased freedom highly beneficial. Regardless, the deformation of the soft manipulator poses a challenge to its actuation, resulting in undesired vibrations. Additionally, the actuation process itself, characterised by the utilisation of pumping power, represents a significant factor contributing to the observed vibrations. This research focuses on the deformations and vibration analysis of the soft manipulator through experiments. The vibration is characterised by the ripple factor obtained from the fluctuation of the linear and angular positions with respect to changing velocity and time. Initially, an optimised model is constructed based on geometric parameters to maximise deflection. Subsequently, vibration analysis is conducted on the optimised model with three different test fluids: water, engine oil, and mustard oil with large viscosity differences at the same temperature, to identify the most suitable fluid in terms of viscosity for actuation. Based on numerical and experimental analysis, engine oil is selected as the most suitable fluid due to its deformation capability at low Reynolds numbers, as well as its vibration control characteristics. This optimal fluid is then used for various test scenarios involving the geometric model. Finally, numerical results are validated with experimental data.

Dhaka Univ. J. Sci. 74(1): 87-94, 2026 (January)