Biomedical soft robots: current status and perspective

T. Ashuri,A. Armani,R. Jalilzadeh Hamidi,T. Reasnor,S. Ahmadi,K. Iqbal 대한의용생체공학회 2020 Biomedical Engineering Letters (BMEL) Vol.10 No.3

This paper reviews the current status of soft robots in biomedical fi eld. Soft robots are made of materials that have comparablemodulus of elasticity to that of biological systems. Several advantages of soft robots over rigid robots are safe human interaction,ease of adaptation with wearable electronics and simpler gripping. We review design factors of soft robots includingmodeling, controls, actuation, fabrication and application, as well as their limitations and future work. For modeling, wesurvey kinematic, multibody and numerical fi nite element methods. Finite element methods are better suited for the analysisof soft robots, since they can accurately model nonlinearities in geometry and materials. However, their real-time integrationwith controls is challenging. We categorize the controls of soft robots as model-based and model-free. Model-free controllersdo not rely on an explicit analytical or numerical model of the soft robot to perform actuation. Actuation is the abilityto exert a force using actuators such as shape memory alloys, fl uid gels, elastomers and piezoelectrics. Nonlinear geometryand materials of soft robots restrict using conventional rigid body controls. The fabrication techniques used for soft robotsdiff er signifi cantly from that of rigid robots. We survey a wide range of techniques used for fabrication of soft robots fromsimple molding to more advanced additive manufacturing methods such as 3D printing. We discuss the applications andlimitations of biomedical soft robots covering aspects such as functionality, ease of use and cost. The paper concludes withthe future discoveries in the emerging fi eld of soft robots.

상지 보조 소프트로봇의 의복화를 위한 디자인 개발 프로세스

홍유화 ( Yuhwa Hong ),박주연 ( Juyeon Park ),남윤자 ( Yun Ja Nam ),박대근 ( Daegeun Park ),조규진 ( Kyu-jin Cho ),김연주 ( Youn Joo Kim ) 한국의류산업학회 2021 한국의류산업학회지 Vol.23 No.1

This study proposes a design process for an upper limb assistive wearable soft robot that will enable the development of a clothing product for an upper limb assistive soft robot. A soft robot made of a flexible and soft material that compensates for the shortcomings of existing upper limb muscle strength assistive devices is being developed. Consequently, a clothing process of the upper limb assistive soft robot is required to increase the possibility of wearing such a device. The design process of the upper limb auxiliary soft robot is presented as follows. User analysis and required performance deduction-Soft robot design-upper limb assistive wearable soft robot prototype design and production-evaluation. After designing the clothing according to the design process, the design was revised and supplemented repeatedly according to the results of the clothing evaluation. In the post-production evaluation stage, the first and second prototypes were attached to actual subjects, and the second prototype showed better results. The developed soft robot evaluated if the functionality as a clothing function and the functionality as the utility of the device were harmonized. The convergence study utilized a process of reducing friction conducted through an understanding and cooperation between research fields. The results of this study can be used as basic data to establish the direction of prototype development in fusion research.

Development of New Soft Actuator Using Magnetic Intelligent Fluids for Flexible Walking Robot

Hironari Taniguchi,Masaki Miyake,Koichi Suzumori 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

The purpose of my work is to develop a new soft actuator with magnetic intelligent fluids such as a magnetic fluid and a magneto-rheological fluid for flexible walking robots. For this purpose, the authors have produced two types of soft magnetic materials. One is called the magnetic fluid rubber that consists of an isoparaffin-based magnetic fluid and elastic silicone rubber. The other is called the magneto-rheological fluid rubber that consists of a polyalphaolefin-based magneto-rheological fluid and elastic silicone rubber. We have developed four types of cylindrical soft actuators using proposed soft magnetic materials. An experimental system was constructed and a response test was made using it. A Laser displacement sensor was employed to find the relationships between the magnetic flux density and the displacement of soft actuator. The experiment showed that the responsibility of soft actuator with the magnetic fluid rubber indicated the best performance. In addition, we operated four electromagnetic coils to control the direction and the displacement of soft actuator. As a result, we have succeeded in moving the tip of soft actuator like drawing a circle. We represented a first possible step towards the development of soft actuator with magnetic functional fluids for flexible walking robots.

Soft Robot Review

이치원,KIMSUNGWAN,김명준,김윤재,홍나영,류승완,김현진 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.1

Soft robots are often inspired from biological systems which consist of soft materials or are actuated byelectrically activated materials. There are several advantages of soft robots compared to the conventional robots;safe human-machine interaction, adaptability to wearable devices, simple gripping system, and so on. Due to theunique features and advantages, soft robots have a considerable range of applications. This article reviews stateof-the-art researches on soft robots and application areas. Actuation systems for soft robots can be categorizedand analyzed into three types: variable length tendon, fluidic actuation, and electro-active polymer (EAP). The deformableproperty of soft robots restricts the use of many conventional rigid sensors such as encoders, strain gauges,or inertial measurement units. Thus, contactless approaches for sensing and/or sensors with low modulus are preferablefor soft robots. Sensors include low modulus (< 1 MPa) elastomers with liquid-phase material filled channelsand are appropriate for proprioception which is determined by the degree of curvature. In control perspective, novelcontrol idea should be developed because the conventional control techniques may be inadequate to handle softrobots. Several innovative techniques and diverse materials & fabrication methods are described in this review article. In addition, a wide range of soft robots are characterized and analyzed based on the following sub-categories;actuation, sensing, structure, control and electronics, materials, fabrication and system, and applications.

Towards Nanomaterial-Incorporated Soft Actuators: from Inorganic/Organic Material-Based Soft Robot to Biomaterial-Based Biohybrid Robot

신민규,Kim Seewoo,Melvin Ambrose Ashwin,Choi Jeong-Woo 한국바이오칩학회 2024 BioChip Journal Vol.18 No.1

Soft actuators have played an indispensable part in the fi eld of biosensors and soft robotics as such systems offer solutions that cannot be addressed with rigid actuators due to the lack of both flexibility and sensitivity. However, soft actuators have certain limitations when it comes to their durability and longevity. In recent years, quite a few versatile fabrication techniques and innovative solutions have been developed that have played an essential role in the development of soft robotics. An exemplary innovation involves the integration of nanomaterials into polymers that act as a host in the fabrication of inorganic/organic actuators. These actuators have shown significant enhancement both in their physical and chemical properties. Consequently, it paves the way for the development of sophisticated soft actuator-based devices that can find broader applications in the field of biomedical sciences. However, biocompatibility has been a matter of concern for inorganic/organic soft actuators. Addressing this issue, studies on the development of biomaterial-based soft actuators that incorporate nanomaterials have been conducted for biohybrid robots. This review aims to provide a comprehensive understanding of diverse stimulus-trigger actuation alongside exploring the influence of nanomaterials in inorganic/organic actuators. Further, it gives valuable insights into the implication of biomaterials in soft actuators for the development of biohybrid robot.

Triboelectric-Based Film-Type Soft Robot Driven via Low-Frequency Mechanical Stimuli

Sungho Ji,Jaehee Shin,Jiyoung Yoon,Jung-Hwan Youn,Jihyeong Ma,Ki-Uk Kyung,Duck Hwan Kim,Hanchul Cho,Jinhyoung Park 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.4

Triboelectric nanogenerators (TENGs) have received considerable attention owing to their ability to harvest energy from the environment. They can be effectively used as a self-generating power source to drive low-power devices. Compared with other energy harvesting technologies, the energy conversion efficiency is much higher, but the current output is low—only enough to drive an existing rotor-type motor. In this study, we designed a film-type soft robot that can produce high-voltage, low-power, triboelectric output without using a motor. Polyvinylidene fluoride (PVDF) film was used as the actuator for the soft robot. We designed a resonance structure to increase the movement of the soft robot driven by low-frequency triboelectric output. A driving test was performed by simulating the shape of butterfly wings and an inch-worm. When the butterfly-shaped PVDF film robot simulated the flapping motion of wings using the resonance structure parameter design, it was able to generate 2.5 times greater movement than the model without the resonance structure. In addition, the artificial inch-worm soft robot optimized for the TENG input was fabricated by applying the parameter design method to the PVDF film. We developed and tested a self-powered, intelligent soft robot that can be driven by low-frequency mechanical stimuli. This study can help extend the application of triboelectric generators.

Multiple-degrees-of-freedom dielectric elastomer actuators for soft printable hexapod robot

Nguyen, Canh Toan,Phung, Hoa,Nguyen, Tien Dat,Jung, Hosang,Choi, Hyouk Ryeol Elsevier 2017 Sensors and actuators. A Physical Vol.267 No.-

<P><B>Abstract</B></P> <P>In this paper, we present the development of a printable hexapod walking robot driven by the multiple-degrees-of-freedom (multi-DOF) soft actuators based on dielectric elastomer. The multi-DOF soft actuators are employed to provide versatile movements including two translations and single rotation within a simple structure based on the antagonistic configuration of two elastomer membranes. The soft actuators demonstrate the potential of being used as a multifunctional joint to actuate the robot leg’s motion which biologically mimics the animal’s walking posture. The actuator performances are enhanced by developing the novel mixed silicone compound, Wacker P7670 and Nusil CF2-2186, and applying the optimized prestrain to the silicone-based actuator membranes. A theoretically and experimentally comprehensive study was carried out to investigate the soft actuators performances in terms of linear displacements, deflection angle, output force, torque, dynamic response, and load carrying capability. We successfully demonstrated the robot’s locomotion on the flat rigid surfaces with the forward and backward walking movements at an average speed of 3cm/s (about 12 body-lengths/min) using the alternating tripod walking gait of insects.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The application of the multiple-degrees-of-freedom (multi-DOF) soft actuators based on dielectric elastomer in driving the locomotion of a hexapod walking robot is presented in this paper. </LI> <LI> The actuator performances are significantly enhanced by replacing the synthetic elastomer with the novel mixed silicone compound, Wacker P7670 and Nusil CF2-2186, and applying the optimized prestrain to the silicone-based actuator membranes. </LI> <LI> The hexapod robot’s fabrication process is implemented using 3D printing technology which provides the lightweight, scalable, and easy-to-manufacture characteristic of the robot. </LI> <LI> A theoretically and experimentally comprehensive study is carried out to investigate the soft actuators performances in terms of linear displacements, deflection angle, output force, torque, dynamic response, and load carrying capability. </LI> <LI> The hexapod robot’s locomotion on flat rigid surfaces with the forward and backward walking movements at an average speed of 3cm/s (about 12 body-lengths/min) using the alternating tripod walking gait of insects is successfully demonstrated. </LI> </UL> </P>

유연한 착용형 손 로봇 기술 동향

인현기(Hyunki In),정우석(Useok Jeong),강병현(Byunghyun Kang),이해민(Haemin Lee),구인욱(Inwook Koo),조규진(Kyu-Jin Cho) 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.6

Hand function is one of the essential functions required to perform the activities of daily living, and wearable robots that assist or recover hand functions have been consistently developed. Previously, wearable robots commonly employed conventional robotic technology such as linkage which consists of rigid links and pin joints. Recently, as the interest in soft robotics has increased, many attempts to develop a wearable robot with a soft structure have been made and are in progress in order to reduce size and weight. This paper presents the concept of a soft wearable robot composed of a soft structure by comparing it with conventional wearable robots. After that, currently developed soft wearable robots and related issues are introduced.

Deformable-wheel robot based on soft material

이대영,고제성,김지석,김승원,조규진 한국정밀공학회 2013 International Journal of Precision Engineering and Vol.14 No.8

Soft robotics, a concept contrary to conventional “hard” robotics, is a robot design methodology that uses soft materials inspired by nature. In contrast to a hard robot, a soft robot is composed of soft and flexible materials that blur the distinction between an actuator and a structure, which leads to unique characteristics that cannot be found in a conventional hard robot. This paper presents our approach to the issues that arise when the concept of soft robotics is applied to a wheeled robot. The compliance of the wheel diversifies its potential movement and allows for a high degree of adaptability to the environment. Although the wheel radius of the robot is 50 mm, it can pass through a 30 mm gap and climb a 45 mm step. While soft robotics displays properties whose performance can be challenging to implement, it also enables us to create complex forms of movement in a cheaper and simpler way. We expect that this kind of approach can provide a new design method for a deformable wheel.

3D printing for soft robotics – a review

Gul, Jahan Zeb,Sajid, Memoon,Rehman, Muhammad Muqeet,Siddiqui, Ghayas Uddin,Shah, Imran,Kim, Kyung-Hwan,Lee, Jae-Wook,Choi, Kyung Hyun TaylorFrancis 2018 SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS Vol.19 No.1

<P><B>Abstract</B></P><P>Soft robots have received an increasing attention due to their advantages of high flexibility and safety for human operators but the fabrication is a challenge. Recently, 3D printing has been used as a key technology to fabricate soft robots because of high quality and printing multiple materials at the same time. Functional soft materials are particularly well suited for soft robotics due to a wide range of stimulants and sensitive demonstration of large deformations, high motion complexities and varied multi-functionalities. This review comprises a detailed survey of 3D printing in soft robotics. The development of key 3D printing technologies and new materials along with composites for soft robotic applications is investigated. A brief summary of 3D-printed soft devices suitable for medical to industrial applications is also included. The growing research on both 3D printing and soft robotics needs a summary of the major reported studies and the authors believe that this review article serves the purpose.</P>