Abstract
Using soft pneumatic actuator is a feasible solution in the complex unstructured environment, owing to their inherent compliance, light weight, and safety. However, due to the limitations of soft actuators' materials and structures, they fall short of motion accuracy and load capacity, or need large-size, bulky compressors. Meanwhile, in order to gain better control, it is essential for them to sense the environments as well. This leads to high-price sensors or a complicated manufacture technique. Here, a self-sensing vacuum soft actuation structure is proposed, aiming at acquiring good balance among precision, output force, and actuation pressure. The actuator mainly comprises a flexible membrane and a compression spring. When actuated, the flexible membrane outside the actuator compresses the internal spring skeleton, realizing large contractile motion in axial direction. Its built-in force sensor can indirectly measure the absolute displacement of the actuator with certain accuracy (about 5% F.S.). Besides, it does not require high actuation pressure to generate enough output force. The actuator is quite easy to manufacture with low cost, and there are a variety of materials to choose from. We established quasi-static models for actuators built of two different kinds of membrane materials, and tested their accuracy and output force. In addition, to break through the limits of vacuum actuation, a method of positive-negative pressure combined actuation has been proposed, which lowers the requirements for air source equipments, increases actuation pressure, and reduces potential safety threats at the same time. This kind of soft actuators can also effectively resist and detect impacts. The design of a two-finger dexterous robot hand and robot joint based on this soft actuator illustrates its broad application prospects in the fields of mobile robots, wearable devices, and human–robot interaction.
Highlights
Soft actuators, relative to rigid mechanical structures, have been widely used in rescue, medical care, wearable devices (Ilievski et al, 2011; Kim et al, 2013; Cianchetti et al, 2014; Park et al, 2014; Rus and Tolley, 2015), etc, owing to their inherent compliance and safety
We present a novel linear actuator Self-sensing Pneumatic Compressing Artificial Muscle (SPCAM) based on the work of Li et al (2017), but there are several key improvements
One end of the actuator is fixed to the base, and the other end is connected to the external tension sensor via a pulley, we can detect the output force
Summary
Relative to rigid mechanical structures, have been widely used in rescue, medical care, wearable devices (Ilievski et al, 2011; Kim et al, 2013; Cianchetti et al, 2014; Park et al, 2014; Rus and Tolley, 2015), etc, owing to their inherent compliance and safety. Liquid–based resistive sensors can be tuned by modulation of channel geometries, and are able to measure various types of strains (Vogt et al, 2013), have acquired wide attention in applications like soft robotic hand (Wall et al, 2017), wearable devices (Kramer et al, 2011b), and human fingers (Kramer et al, 2011a). They suffer the large temperature drift due to the correlation between temperature and ion concentration.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
