Fabrication of a Polyimide Film Pneumatic Actuator by Molding and Welding Processes

The bellows pneumatic actuator, which is made by folding a non-stretch film, has been proposed for various applications because it is easy to fabricate and is extremely thin and light. However, it has subpar durability performance, especially in the folded part of the film. In this study, we propose an actuator with a pod structure that possesses high design flexibility and is free from folding. A method of molding a pod structure on a polyimide film was established and a pneumatic actuator was successfully fabricated by using PI films. Two types of PI film pneumatic actuators with the same curvature, bellows type, and pod type were fabricated. Both were confirmed to have equivalent output characteristics. The bending angle and generated torque of the pod-structure actuator were 34 degrees and 3.3 mNm, respectively. In addition, the pod structure has approximately twice the durability of the bellows structure. By using the fabrication method proposed in this paper, it is possible to realize an air chamber (i.e., an actuator) that has both high durability and bending motion

The Design and Manufacturing of Soft Robotic Pneumatic Actuators

As technology is advances, people are beginning to see more cybernetic enhancements to compensate for mechanical deficiencies. One area of focus is on bio medics, particularly regarding prosthesis; As the overall health status in the US decreases those needing prosthetic mechanisms increases, due to this, more effective systems should be considered. This is the basis for this research topic: to apply soft robotics pneumatic actuation to a gripper system that closely reflects the mobility and dexterity of the average human being of today. The important factors considered in the design of an efficient actuator using soft robotic actuation is the efficiency of actuation with pressure, bending angle achieved at certain pressures and optimizations considering different actuator designs and medium transitions for optimizing the finger. Current implementations of the actuator configuration have been able to reveal major design flaws and critical aspects that would affect the efficiency of the actuator. These proclivities have resulted in an actuator system incapable of producing a force generation profile significant enough to conclude the systems validity, and as such requires more testing and analysis due to issues experienced in the fabrication process. With the development of a successful actuator design in future work, this project would seek to optimize the systems actuation methods before implementation of sensory encoders or layer jamming systems.No embargoAcademic Major: Mechanical Engineerin

Design and Fabrication of Soft 3D Printed Actuators: Expanding Soft Robotics Applications

Soft pneumatic actuators are ideal for soft robotic applications due to their innate compliance and high power-weight ratios. Presently, the majority of soft pneumatic actuators are used to create bending motions, with very few able to produce significant linear movements. Fewer can actively produce strains in multiple directions. The further development of these actuators is limited by their fabrication methods, specifically the lack of suitable stretchable materials for 3D printing. In this thesis, a new highly elastic resin for digital light projection 3D printers, designated ElastAMBER, is developed and evaluated, which shows improvements over previously synthesised elastic resins. It is prepared from a di-functional polyether urethane acrylate oligomer and a blend of two different diluent monomers. ElastAMBER exhibits a viscosity of 1000 mPa.s at 40 °C, allowing easy printing at near room temperatures. The 3D-printed components present an elastomeric behaviour with a maximum extension ratio of 4.02 ± 0.06, an ultimate tensile strength of (1.23 ± 0.09) MPa, low hysteresis, and negligible viscoelastic relaxation

Projeto de luva pneumática para ajuda na reabilitação da mão

Trabalho final de Mestrado para obtenção do grau de Mestre em Engenharia Biomédica.A perda da funcionalidade da mão interfere com o desempenho das atividades diárias conduzindo a uma redução considerável da qualidade de vida do indivíduo. A introdução de dispositivos vestíveis nas estratégias de reabilitação assistida tem vindo a demonstrar resultados eficazes na recuperação. O objetivo deste trabalho passou pela criação de uma luva composta por atuadores pneumáticos que eficazmente facilitasse o processo de assistência à reabilitação da mão. Neste projeto foram utilizadas várias áreas e tecnologias, desde a robótica macia para a criação dos protótipos dos atuadores pneumáticos macios até ao software CAD e impressão 3D para a criação dos seus moldes. Foi realizado também um estudo computacional, com recurso à análise por Elementos Finitos, que permitiu concluir que a estrutura física do atuador conseguiria cumprir a sua função, ou seja, confirmou a correta flexão dos atuadores. Além disso, confirmou que com um maior incremento de pressão interna a dilatação entre duas câmaras adjacentes aumenta proporcionalmente. Após a análise por simulação foram construídos os protótipos dos atuadores pneumáticos macios e a luva pneumática para a reabilitação da mão. Os ensaios experimentais dos atuadores e da luva demonstraram a concordância com os resultados das simulações e da literatura. Os valores de pressão máxima para a flexão normal dos atuadores estão no intervalo de 100 kPa e 150 kPa e os ângulos máximos de flexão entre 120º e 160º. Por fim, foram selecionados cinco dos sete atuadores desenvolvidos que foram colocados na luva construída em tecido elástico, sendo este depois alvo de teste de preensão com objetos diferentes.The loss of hand functionality interferes with the performance of daily activities leading to a considerable reduction in the quality of life of the individual. The introduction of wearable devices in assisted rehabilitation strategies has shown effective results in recovery. The aim of this work was to create a glove composed of pneumatic actuators that effectively facilitates the process of assisted hand rehabilitation. Several areas and technologies were used in this project, from soft robotics for the creation of the prototypes of the soft pneumatic actuators to CAD software and 3D printing for the creation of their molds. A computational study was also performed, using Finite Element analysis, which allowed concluding that the physical structure of the actuator could fulfil its function, i.e., it confirmed the correct bending of the actuators. Furthermore, it confirmed that with a higher internal pressure increment the dilatation between two adjacent chambers increases proportionally. After the simulation analysis the prototypes of the soft pneumatic actuators and the pneumatic glove for hand rehabilitation were built. The experimental tests of the actuators and the sleeve demonstrated the agreement with the simulation results and literature. The maximum pressure values for normal bending of the actuators are in the range of 100 kPa and 150 kPa, and the maximum bending angles are between 120° and 160°. Finally, five of the seven actuators developed were selected and placed on the glove made of elastic fabric, which was then subjected to a grip test with different objects.N/

A structural optimisation method for a soft pneumatic actuator

This study aims to investigate the effects of various design parameters on the actuation performance of a pneumatic network actuator (PNA), optimise its structure using the finite element method (FEM), and subsequently quantify the performance of the resulting actuator topology experimentally. The effects of the structural parameters, including the operation pressure, the wall thickness and the gap between the chambers, bottom layer thickness, and the geometry of the channel cross section, on the deformation and bending angle of the actuator were evaluated to optimise the performance of the pneumatic actuator. A Global Analysis of Variance (ANOVA) was performed to investigate how the variables affect the mechanical output of the actuator and, thus, the significance of variables affecting the deformation (and bending angle) of the pneumatic actuator was identified. After the parameter optimisation, a pneumatic channel with a 4.5 mm bottom layer thickness, 1.5 mm wall thickness, and 1.5 mm gap between sequential chambers is recommended to perform optimised bending motion for the pneumatic network actuator. The optimised FE model results were verified experimentally. This design optimisation method based on the FEM and ANOVA analysis can be extended to the topology optimisation of other soft actuators