Design and modelling of a fluid inerter

Mechanical spring-damper network performance can often be improved by the inclusion of a third passive component called the inerter. This ideally has the characteristic that the force at the terminals is directly proportional to the relative acceleration between them. The fluid inerter presented here has advantages over mechanical ball screw devices in terms of simplicity of design. Furthermore, it can be readily adapted to implement various passive network layouts. Variable orifices and valves can be included to provide series or parallel damping. Test data from prototypes with helical tubes have been compared with models to investigate parasitic damping effects of the fluid. © 2013 Copyright Taylor and Francis Group, LLC.

Design and modeling of an integrated device for acoustic resonance spectroscopy

This paper investigates the design and modelling of an integrated device for acoustic resonance spectroscopy (ARS). Miniaturisation of such platforms can be achieved using MEMS technology thereby enabling scaling of device dimensions to investigate smaller specimens while simultaneously operating at higher frequencies. We propose an integrated device where the transducers are mounted in close proximity with the specimen to be analysed (e.g. by integrating ultrasound transducers within a microfluidic channel). A finite element (FE) model and a simplified analytical model have been constructed to predict the acoustic response of a sample embedded in such a device configuration. A FE simulation is performed in COMSOL by embedding the piezoelectric transducers in representative fluid media. Resonant frequencies associated with the measurement can be extracted from this data. The response of various media modelled through FEA matches with analytical predictions for a range of biological media. A variety of biological media may be identified by using the measured resonant frequencies as a signature of relevant physical characteristics. The paper establishes the modelling basis of an integrated acoustic resonant spectrometer that is then applied to examine the impact of geometrical scaling on system resolution. © 2013 IEEE.

Design and control of a climbing robot based on hot melt adhesion

Robust climbing in unstructured environments has been one of the long-standing challenges in robotics research. Among others, the control of large adhesion forces is still an important problem that significantly restricts the locomotion performance of climbing robots. The main contribution of this paper is to propose a novel approach to autonomous robot climbing which makes use of hot melt adhesion (HMA). The HMA material is known as an economical solution to achieve large adhesion forces, which can be varied by controlling the material temperature. For locomotion on both inclined and vertical walls, this paper investigates the basic characteristics of HMA material, and proposes a design and control of a climbing robot that uses the HMA material for attaching and detaching its body to the environment. The robot is equipped with servomotors and thermal control units to actively vary the temperature of the material, and the coordination of these components enables the robot to walk against the gravitational forces even with a relatively large body weight. A real-world platform is used to demonstrate locomotion on a vertical wall, and the experimental result shows the feasibility and overall performances of this approach. © 2013 Elsevier B.V. All rights reserved.

Design and control of a pendulum driven hopping robot

In this paper a new kind of hopping robot has been designed which uses inverse pendulum dynamics to induce bipedal hopping gaits. Its mechanical structure consists of a rigid inverted T-shape mounted on four compliant feet. An upright "T" structure is connected to this by a rotary joint. The horizontal beam of the upright "T" is connected to the vertical beam by a second rotary joint. Using this two degree of freedom mechanical structure, with simple reactive control, the robot is able to perform hopping, walking and running gaits. During walking, it is experimentally shown that the robot can move in a straight line, reverse direction and control its turning radius. The results show that such a simple but versatile robot displays stable locomotion and can be viable for practical applications on uneven terrain.