Review of Biomimetic Mechanism, Actuation, Modeling and Control in Soft Manipulators

Abstract

Soft manipulators are new type of machine mainly made of soft materials. They possess the characteristics of high flexibility, good adaptability to complex environment and safely human-machine interactivity. New soft material and fabrication, the variable stiffening, the flexible sensor are proposed as the key technology and the promising potential research directions of soft manipulators. The research involves a combination of material science, bionics, mechanics and sensor technology. And it provides theoretical and technical guidance for application of soft materials and bionic research. The soft manipulators have been intensively studied for their wide application prospects in the fields of industrial production, minimally invasive surgery, rescue, Nursing Gerontology and so on. The review of existing soft manipulators in terms of bionic principle, actuation, stiffening methods, modeling and control is presented. The bionic mechanism from octopus arms and elephant trunks is introduced. Soft manipulators are summarized as FEA, TDA, PAM, SMA, EAP and hybrid mode by their actuating mechanisms. The methods of stiffening are summarized as antagonistic, jamming and phase change. The common modeling methods and control strategies are also introduced. The difficulties, current issues and possible solutions are discussed. The lack of repeatability, precision, lower output force, modeling and control method can be summarized as limiting factors for their applications. The key technology and future development include the preparation and molding technology, rigid flexible combination / variable stiffness robot, flexible sensor technology and so on.