Geometric optimisation of electroadhesive actuators based on 3D electrostatic simulation and its experimental verification

A systematic research methodology for the performance evaluation of different electroadhesive pad geometries is demonstrated in this paper. The proposed research method for the investigation was based on a 3D electrostatic simulation using COMSOL Multiphysics, a cost-effective electroadhesive pad design and manufacturing process based on solid-ink printing, chemical etching, conformal coating, and an advanced and mechatronic electroadhesive force testing platform and procedure. The method has been validated using 2 novel pad designs, approximate 21 cm x 19 cm, compared with the normal comb design, on the glass and aluminium plate. The experimental results showed that: 1) on the glass substrate, a relative increase of 1% and 28% in the electroadhesive forces obtainable can be seen in the curve-comb pad and the worm-comb pad respectively; and 2) on the Al substrate, a relative increase of 5% and 12% can be seen. This manifests that the two new pad designs, especially the worm-comb shape design, are better at generating larger electroadhesive forces. The comparison between the simulation results and experimental results proved that proposed method is promising for evaluating the pad design before spending time and money on pad manufacture and testing

Stretchable Electroadhesion for Soft Robots

With the ongoing rise of soft robots there emerges a need for new soft robotic technologies that can cope with hyper-flexibility and stretchability. In this paper, we describe our developments on enabling controllable adhesion, namely electroadhesion, for the use in soft robots. We present a method to manufacture stretchable electroadhesive pads and characterize their performance when stretching the pad more than double its original length. Our results suggest that the normal detachment force per area slightly decreases with the stretching, while the shear detachment force per area increase with the stretch ratio. These results imply that stretchable electroadhesive pads have higher adaptivity to a given task compared to non-stretchable pads, because the stretchable pads are adaptable in terms of their mechanical stiffness as well as their adhesive force

Optimization and experimental verification of coplanar interdigital electroadhesives

A simplified and novel theoretical model for coplanar interdigital electroadhesives has been presented in this paper. The model has been verified based on a mechatronic and reconfigurable testing platform, and a repeatable testing procedure. The theoretical results have shown that, for interdigital electroadhesive pads to achieve the maximum electroadhesive forces on non-conductive substrates, there is an optimum electrode width/space between electrodes (width/space) ratio, approximately 1.8. On conductive substrates, however, the width/space ratio should be as large as possible. The 2D electrostatic simulation results have shown that, the optimum ratio is significantly affected by the existence of the air gap and substrate thickness variation. A novel analysis of the force between the electroadhesive pad and the substrate has highlighted the inappropriateness to derive the normal forces by the division of the measured shear forces and the friction coefficients. In addition, the electroadhesive forces obtained in a 5 d period in an ambient environment have highlighted the importance of controlling the environment when testing the pads to validate the models. Based on the confident experimental platform and procedure, the results obtained have validated the theoretical results. The results are useful insights for the investigation into environmentally stable and optimized electroadhesives

Numerical and experimental study of electroadhesion to enable manufacturing automation

Robotics and autonomous systems (RAS) have great potential to propel the world to future growth. Electroadhesion is a promising and potentially revolutionising material handling technology for manufacturing automation applications. There is, however, a lack of an in-depth understanding of this electrostatic adhesion phenomenon based on a confident electroadhesive pad design, manufacture, and testing platform and procedure. This Ph.D. research endeavours to obtain a more comprehensive understanding of electroadhesion based on an extensive literature review, theoretical modelling, electrostatic simulation, and experimental validation based on a repeatable pad design, manufacture, and testing platform and procedure. [Continues.

Challenges in the Locomotion of Self-Reconfigurable Modular Robots

Self-Reconfigurable Modular Robots (SRMRs) are assemblies of autonomous robotic units, referred to as modules, joined together using active connection mechanisms. By changing the connectivity of these modules, SRMRs are able to deliberately change their own shape in order to adapt to new environmental circumstances. One of the main motivations for the development of SRMRs is that conventional robots are limited in their capabilities by their morphology. The promise of the field of self-reconfigurable modular robotics is to design robots that are robust, self-healing, versatile, multi-purpose, and inexpensive. Despite significant efforts by numerous research groups worldwide, the potential advantages of SRMRs have yet to be realized. A high number of degrees of freedom and connectors make SRMRs more versatile, but also more complex both in terms of mechanical design and control algorithms. Scalability issues affect these robots in terms of hardware, low-level control, and high-level planning. In this thesis we identify and target three major challenges: (i) Hardware design; (ii) Planning and control; and, (iii) Application challenges. To tackle the hardware challenges we redesigned and manufactured the Self-Reconfigurable Modular Robot Roombots to meet desired requirements and characteristics. We explored in detail and improved two major mechanical components of an SRMR: the actuation and the connection mechanisms. We also analyzed the use of compliant extensions to increase locomotion performance in terms of locomotion speed and power consumption. We contributed to the control challenge by developing new methods that allow an arbitrary SRMR structure to learn to locomote in an efficient way. We defined a novel bio-inspired locomotion-learning framework that allows the quick and reliable optimization of new gaits after a morphological change due to self-reconfiguration or human construction. In order to find new suitable application scenarios for SRMRs we envision the use of Roombots modules to create Self-Reconfigurable Robotic Furniture. As a first step towards this vision, we explored the use and control of Plug-n-Play Robotic Elements that can augment existing pieces of furniture and create new functionalities in a household to improve quality of life