Abstract:
Flexible pneumatic actuators have been broadly explored in soft robotic engineering field where large strokes are required to interface with objects in delicate environments. Some of them have successfully demonstrated the capability of contracting, expanding, bending, and/or twisting, however their reproducibility, force output, bending capability and customizability of design is still quite limited. This research focused on the development of a precise and effective way of designing a pneumatic bending actuator by using modelling tools and specified winding fabrication technique. The proposed pneumatic bending actuator (PBA) is capable of generating satisfactory force and bending displacement without unwanted radial expansion upon internal fluidic pressure supply. The presented design owns some outstanding attributes, including low profile, light weight, compliant nature and robustness. A systematic characterization and investigation on the output of PBA across a range of parameters makes the entire design process highly controllable and applicable to a large variety of applications. The entire research could be divided into three parts. The first section mainly involves the proof of concepts and fabrication try-outs to successfully develop a PBA using controllable and repeatable fabrication technique. The proposed bimorph-like PBA is sufficiently strong to withhold high-pressure supply and capable of producing bending displacement and bending force to a satisfactory level. In the middle section, a rational behind design is explained through modelling and simulation. A systematic characterization and investigation on proposed PBA gives insights to understand the its behavior and makes the entire design process highly controllable, parameterizable and customizable. To demonstrate practicability of proposed FBA in real world application, two examples of its application in engineering field are presented in the end. The first example involves the development of a rehabilitation glove by upgrading the previously designed bimorph-like PBA to a hybrid type, bi-directional bending actuator. The complete prototype of hand rehabilitation system is consisted of a FBA-based rehabilitation glove, control kit and user interface, which shows good repeatability and controllability. Attributed to its light weight, low profile, anthropomorphic form, satisfactory output force and angular displacement in both contraction and expansion stroke, it could provide a pragmatic solution to an automatic robot-aided post-stroke hand rehabilitation system. In the second case of application, the prototype of a soft gripper to interface with delicate objects using the novel bimorph-like PBA is presented. The gripper was modelled through finite element analysis to reflect its gripping capability during interaction with certain targeted objects and validated via preliminary experiments on objects of different weight and size.