Design, additive manufacturing and component testing of pneumatic rotary vane actuators for lightweight robots

Abstract

Purpose This study aims to investigate the suitability of a multi-step prototyping strategy for producing pneumatic rotary vane actuators (RVAs) for the development of lightweight robots and actuation systems. Design/methodology/approach RVAs typically have cast aluminum housings and injection-molded seals that consist of hard thermoplastic cores and soft elastomeric overmolds. Using a combination of additive manufacturing (AM), computer numerical control (CNC) machining and elastomer molding, a conventionally manufactured standard RVA was replicated. The standard housing design was modified, and polymeric replicas were obtained by selective laser sintering (SLS) or PolyJet (PJ) printing and subsequent CNC milling. Using laser-sintered molds, actuator seals were replicated by overmolding laser-sintered polyamide cores with silicone (SIL) and polyurethane (PU) elastomers. The replica RVAs were subjected to a series of leakage, friction and durability experiments. Findings The AM-based prototyping strategy described is suitable for producing functional and reliable RVAs for research and product development. In a representative durability experiment, the RVAs in this study endured between 40,000 and 1,000,000 load cycles. Frictional torques were around 0.5 Nm, which is 10% of the theoretical torque at 6 bar and comparable to that of the standard RVA. Models and parameters are provided for describing the velocity-dependent frictional torque. Leakage experiments at 10,000 load cycles and 6 bar differential pressure showed that PJ housings exhibit lower leakage values (6.8 L/min) than laser-sintered housings (15.2 L/min), and PU seals exhibit lower values (8.0 l/min) than SIL seals (14.0 L/min). Combining PU seals with PJ housings led to an initial leakage of 0.4 L/min, which increased to only 1.2 L/min after 10,000 load cycles. Overall, the PU material used was more difficult to process but also more abrasion- and tear-resistant than the SIL elastomer. Research limitations/implications More work is needed to understand individual cause–effect relationships between specific design features and system behavior. Originality/value To date, pneumatic RVAs have been manufactured by large-scale production technologies. The absence of suitable prototyping strategies has limited the available range to fixed sizes and has thus complicated the use of RVAs in research and product development. This paper proves that functional pneumatic RVAs can be produced by using more accessible manufacturing technologies and provides the tools for prototyping of application-specific RVAs.

Design, Topology Optimization, and Additive Manufacturing of a Pneumatically Actuated Lightweight Robot

“…The manufacturing of the robot involved three-dimensional (3D) inkjet printing and selective laser sintering as well as using these processes for the manufacturing of molds [46]. Three-dimensional (3D) inkjet printing is a material jetting process in which piezo nozzles are used to deposit droplets of acrylate-based inks.…”

“…Integration of the mechanical and pneumatic systems to form the final robot design is presented in Section 4. Parallel publications deal with the development of AM RVAs [46], soft AM-based bellows actuators [45,47], and the robot's gripper [44] with an integrated printed soft actuator.…”

Active Control of Diesel Engine Exhaust Noise Incorporating Widrow-hoff LMS Algorithm

“…For the EN, its size is related to the DE noise source, the whole exhaust system assembly arrangement, the exhaust pipe diameter and the internal structure of the exhaust muffler, etc. However, since the DE technology has been mature for a long time, it is difficult to continue to reduce the noise from the consideration of the noise source, and the space limitation of the DE makes it difficult to change the whole exhaust assembly arrangement [9]. Therefore, the current method of improving the design of the internal structure of exhaust muffler and the diameter of exhaust connection pipe to reduce EN is widely used.…”

Additive Manufacturing of Biomaterials—Design Principles and Their Implementation

“…Additive manufacturing (AM, also known as 3D printing) technologies are among the most feasible advanced manufacturing options to create complex structures for use in technology-driven industries, such as healthcare [ 1 ], automotive [ 2 , 3 ], and aerospace [ 4 ]. AM, being different from other manufacturing methods, such as subtractive and formative methods, results in less scrap and waste of materials and allows for lightweight complex structures, often hollow or porous, thus requiring less material input and energy input during their fabrication and service.…”