High-performance artificial muscle is of great interest to robotics community. In this study, we investigate the influence of pre-stress on fishing line artificial muscle's tensile stroke. Fishing line artificial muscles with electrothermal actuation were made from nylon 6 mono-filament and resistance wires. The tensile stroke in time domain was found to exhibit different actuation behavior under different levels of pre-stress in spring-load test. The supplied current was kept constant through all the experimental tests to investigate the effect of prestress on the artificial muscle performance. The presented study provided new insight into implementation of fishing line artificial muscle towards robotic applications, especially regarding how to choose appropriate pre-stress for muscle integration.
This paper describes the design and manufacturing of a modular actuator unit based on twisted and coiled polymer actuator. Twisted and coiled polymer actuators have attracted attention in the field of smart actuators and robotics. The proposed concept allows for the improvement of the response time of the twisted and coiled polymer actuator by incorporating active cooling method. This realization results in the development of modular actuator unit for bio-robotic system. The modular actuator unit consist of several twisted and coiled polymer actuators, a 3D printed frame and DC fans. The design and manufacturing of such modular actuator unit will be discussed in detail. Preliminary results about the performance of the twisted and coiled polymer actuators will also be presented.
Actuators are the most important elements that affect the performance of biorobotic systems design and development. One of the objectives of this project is to design stronger, lighter, 3D printable, functionally graded bone-like structures and bio-inspired musculoskeletal system for the articulation of robots. Another objective is to identify the fundamental science of manufacturing and modeling of the muscle systems. A modular building block is presented consisting of bone-like structures, cartilages and artificial muscles (that are inexpensive and powerful), which can be cascaded to create complex robots. In this paper, we present terrestrial robots as a demonstration of the building blocks for biorobotic systems. We particularly illustrate a humanoid robot developed using soft actuators based on twisted and coiled polymer (TCP) muscles. The integration of TCPs in biorobotic systems has some challenges to overcome such as initial pre-stress, adding multiple actuators in parallel or in antagonistic pair and speed of actuation and other accessories. We will quantify the performance of these robots experimentally. We presented two TCP muscles types, one without heating element and the other one that incorporates a heating element that allows electrical actuation.
This paper describes the design and experimental investigation of a self-reconfigurable icosahedral robot for locomotion. The robot consists of novel and modular tensegrity structures, which can potentially maneuver in unstructured environments while carrying a payload. Twisted and Coiled Polymer (TCP) muscles were utilized to actuate the tensegrity structure as needed. The tensegrity system has rigid struts and flexible TCP muscles that allow keeping a payload in the central region. The TCP muscles provide large actuation stroke, high mechanical power per fiber mass and can undergo millions of highly reversible cycles. The muscles are electrothermally driven, and, upon stimulus, the heated muscles reconfigure the shape of the tensegrity structure. Here, we present preliminary experimental results that determine the rolling motion of the structure.
This paper describes the design and experimental analysis of novel artificial muscles, made of twisted and coiled nylon fibers, for powering a biomimetic robotic hand. The design is based on circulating hot and cold water to actuate the artificial muscles and obtain fast finger movements. The actuation system consists of a spring and a coiled muscle within a compliant silicone tube. The silicone tube provides a watertight, expansible compartment within which the coiled muscle contracts when heated and expands when cooled. The fabrication and characterization of the actuating system are discussed in detail. The performance of the coiled muscle fiber in embedded conditions and the related characteristics of the actuated robotic finger are described.
A soft robotic device inspired by the pumping action of a biological heart is presented in this study. Developing
artificial heart to a humanoid robot enables us to make a better biomedical device for ultimate use in humans. As
technology continues to become more advanced, the methods in which we implement high performance and
biomimetic artificial organs is getting nearer each day. In this paper, we present the design and development of a
soft artificial heart that can be used in a humanoid robot and simulate the functions of a human heart using shape
memory alloy technology. The robotic heart is designed to pump a blood-like fluid to parts of the robot such as the
face to simulate someone blushing or when someone is angry by the use of elastomeric substrates and certain
features for the transport of fluids.