Soft robotics enables the design of soft machines and devices at different scales. The compliance and mechanical properties of soft robots make them especially interesting for medical applications. Depending on the level of interaction with humans, different levels of biocompatibility and biomimicry are required for soft materials used in robots. In this Review, we investigate soft robots for biomedical applications, including soft tools for surgery, diagnosis and drug delivery, wearable and assistive devices, prostheses, artificial organs and tissue-mimicking active simulators for training and biomechanical studies. We highlight challenges regarding durability and reliability, and examine traditional and novel soft and active materials as well as different actuation strategies. Finally, we discuss future approaches and applications in the field. Soft robots have broad applications in medicine. In this Review, biomedical applications, including surgery, drug delivery, prostheses, wearable devices and artificial organs, are discussed in the context of materials, actuation strategies and challenges.

Biomedical applications of soft robotics

Recently, researchers started to engineer not only the outer shape of objects, but also their internal microstructure. Such objects, typically based on 3D cell grids, are also known as metamaterials. Metamaterials have been used, for example, to create materials with soft and hard regions.So far, metamaterials were understood as materials-we want to think of them as machines. We demonstrate metamaterial objects that perform a mechanical function. Such metamaterial mechanisms consist of a single block of material the cells of which play together in a well-defined way in order to achieve macroscopic movement. Our metamaterial door latch, for example, transforms the rotary movement of its handle into a linear motion of the latch. Our metamaterial Jansen walker consists of a single block of cells-that can walk. The key element behind our metamaterial mechanisms is a specialized type of cell, the only ability of which is to shear.In order to allow users to create metamaterial mechanisms efficiently we implemented a specialized 3D editor. It allows users to place different types of cells, including the shear cell, thereby allowing users to add mechanical functionality to their objects. To help users verify their designs during editing, our editor allows users to apply forces and simulates how the object deforms in response.

Metamaterial Mechanisms

A Review of Thickness-Accommodation Techniques in Origami-Inspired Engineering

\n Flexure-based compliant mechanisms are becoming increasingly promising in precision engineering, robotics, and other applications due to the excellent advantages of no friction, no backlash, no wear, and minimal requirement of assembly. Because compliant mechanisms have inherent coupling of kinematic-mechanical behaviors with large deflections and/or complex serial-parallel configurations, the kinetostatic and dynamic analyses are challenging in comparison to their rigid-body counterparts. To address these challenges, a variety of techniques have been reported in a growing stream of publications. This paper surveys and compares the conceptual ideas, key advances, and applicable scopes, and open problems of the state-of-the-art kinetostatic and dynamic modeling methods for compliant mechanisms in terms of small and large deflections. Future challenges are discussed and new opportunities for extended study are highlighted as well. The presented review provides a guide on how to select suitable modeling approaches for those engaged in the field of compliant mechanisms.

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Kinetostatic and Dynamic Modeling of Flexure-Based Compliant Mechanisms: A Survey

Design and numerical validation of quasi-zero-stiffness metamaterials for very low-frequency band gaps

pt. 1. Introduction to compliant mechanisms -- pt. 2. Modeling of compliant mechanisms -- pt. 3. Synthesis of compliant mechanisms -- pt. 4. Library of compliant mechanisms.

Handbook of compliant mechanisms

Handbook of Compliant Mechanisms: Howell/Handbook

The knowledge related to the synthesis and analysis of compliant mechanisms continues to grow and mature. Building on this growth, a classification scheme has been established to categorize compliant elements and mechanisms in a manner that engineers can incorporate compliance into their designs. This paper demonstrates a design approach engineers can use to convert an existing rigid-body mechanism into a compliant mechanism by using an established classification scheme. This approach proposes two possible techniques that use rigid-body replacement synthesis in conjunction with a compliant mechanism classification scheme. One technique replaces rigid-body elements with a respective compliant element. The other technique replaces a complex rigid-body mechanism by decomposing the mechanism into simpler functions and then replacing a respective rigid-body mechanism with a compliant mechanism that has a similar functionality.Copyright © 2010 by ASME

Utilizing a Classification Scheme to Facilitate Rigid-Body Replacement for Compliant Mechanism Design

A user-selectable force conversion apparatus includes a first and a second connecting member that are pivotally connected to each other between a sliding member and a fixed member. The apparatus also includes a leaf spring holder for removably retaining one or more leaf springs and loading the second connecting member with a substantially linear force response of the leaf springs. A user may change the combination of leaf springs and/or vary a length ratio for the first and second connecting members and thereby change the force response of the apparatus. Movement of the sliding member by the mechanical input may convert the substantially linear force response of the leaf springs to a user-selected force response for the mechanical input. A corresponding method is also disclosed.

User-selectable force conversion apparatus and method

Limited resources are currently available to assist engineers in implementing compliant members into mechanical designs. As a result, engineers often have little to no direction incorporating compliance, though compliant mechanisms have characteristics that prove to be more advantageous in some circumstances. This paper proposes a classification scheme for compliant elements and mechanisms that can be used to compose a reference source intended to help engineers find existing compliant designs they can incorporate in their own designs. The classification scheme decomposes compliant mechanisms and elements of compliant mechanisms according to their respective functions.Copyright © 2009 by ASME

Brian M. Olsen

Papers

Handbook of compliant mechanisms

Handbook of Compliant Mechanisms: Howell/Handbook

Utilizing a Classification Scheme to Facilitate Rigid-Body Replacement for Compliant Mechanism Design

User-selectable force conversion apparatus and method

A Proposed Extendable Classification Scheme for Compliant Mechanisms