Design, Actuation, and Functionalization of Untethered Soft Magnetic Robots with Life-Like Motions: A Review

Soft robots have demonstrated superior flexibility and functionality than conventional rigid robots. These versatile devices can respond to a wide range of external stimuli (including light, magnetic field, heat, electric field, etc.), and can perform sophisticated tasks. Notably, soft magnetic robots exhibit unparalleled advantages among numerous soft robots (such as untethered control, rapid response, and high safety), and have made remarkable progress in small-scale manipulation tasks and biomedical applications. Despite the promising potential, soft magnetic robots are still in their infancy and require significant advancements in terms of fabrication, design principles, and functional development to be viable for real-world applications. Recent progress shows that bionics can serve as an effective tool for developing soft robots. In light of this, the review is presented with two main goals: (i) exploring how innovative bioinspired strategies can revolutionize the design and actuation of soft magnetic robots to realize various life-like motions; (ii) examining how these bionic systems could benefit practical applications in small-scale solid/liquid manipulation and therapeutic/diagnostic-related biomedical fields

Development of Multifunctional E-skin Sensors

Electronic skin (e-skin) is a hot topic due to its enormous potential for health monitoring, functional prosthesis, robotics, and human-machine-interfaces (HMI). For these applications, pressure and temperature sensors and energy harvesters are essential. Their performance may be tuned by their films micro-structuring, either through expensive and time-consuming photolithography techniques or low-cost yet low-tunability approaches. This PhD thesis aimed to introduce and explore a new micro-structuring technique to the field of e-skin – laser engraving – to produce multifunctional e-skin devices able to sense pressure and temperature while being self-powered. This technique was employed to produce moulds for soft lithography, in a low-cost, fast, and highly customizable way. Several parameters of the technique were studied to evaluate their impact in the performance of the devices, such as moulds materials, laser power and speed, and design variables. Amongst the piezoresistive sensors produced, sensors suitable for blood pressure wave detection at the wrist [sensitivity of – 3.2 kPa-1 below 119 Pa, limit of detection (LOD) of 15 Pa], general health monitoring (sensitivity of 4.5 kPa-1 below 10 kPa, relaxation time of 1.4 ms, micro-structured film thickness of only 133 µm), and robotics and functional prosthesis (sensitivity of – 6.4 × 10-3 kPa-1 between 1.2 kPa and 100 kPa, stable output over 27 500 cycles) were obtained. Temperature sensors with micro-cones were achieved with a temperature coefficient of resistance (TCR) of 2.3 %/°C. Energy harvesters based on micro-structured composites of polydimethylsiloxane (PDMS) and zinc tin oxide (ZnSnO3) nanowires (NWs; 120 V and 13 µA at > 100 N) or zinc oxide (ZnO) nanorods (NRs; 6 V at 2.3 N) were produced as well. The work described herein unveils the tremendous potential of the laser engraving technique to produce different e-skin devices with adjustable performance to suit distinct applications, with a high benefit/cost ratio

Inorganic micro/nanostructures-based high-performance flexible electronics for electronic skin application

Electronics in the future will be printed on diverse substrates, benefiting several emerging applications such as electronic skin (e-skin) for robotics/prosthetics, flexible displays, flexible/conformable biosensors, large area electronics, and implantable devices. For such applications, electronics based on inorganic micro/nanostructures (IMNSs) from high mobility materials such as single crystal silicon and compound semiconductors in the form of ultrathin chips, membranes, nanoribbons (NRs), nanowires (NWs) etc., offer promising high-performance solutions compared to conventional organic materials. This thesis presents an investigation of the various forms of IMNSs for high-performance electronics. Active components (from Silicon) and sensor components (from indium tin oxide (ITO), vanadium pentaoxide (V2O5), and zinc oxide (ZnO)) were realised based on the IMNS for application in artificial tactile skin for prosthetics/robotics. Inspired by human tactile sensing, a capacitive-piezoelectric tandem architecture was realised with indium tin oxide (ITO) on a flexible polymer sheet for achieving static (upto 0.25 kPa-1 sensitivity) and dynamic (2.28 kPa-1 sensitivity) tactile sensing. These passive tactile sensors were interfaced in extended gate mode with flexible high-performance metal oxide semiconductor field effect transistors (MOSFETs) fabricated through a scalable process. The developed process enabled wafer scale transfer of ultrathin chips (UTCs) of silicon with various devices (ultrathin chip resistive samples, metal oxide semiconductor (MOS) capacitors and n‐channel MOSFETs) on flexible substrates up to 4″ diameter. The devices were capable of bending upto 1.437 mm radius of curvature and exhibited surface mobility above 330 cm2/V-s, on-to-off current ratios above 4.32 decades, and a subthreshold slope above 0.98 V/decade, under various bending conditions. While UTCs are useful for realizing high-density high-performance micro-electronics on small areas, high-performance electronics on large area flexible substrates along with low-cost fabrication techniques are also important for realizing e-skin. In this regard, two other IMNS forms are investigated in this thesis, namely, NWs and NRs. The controlled selective source/drain doping needed to obtain transistors from such structure remains a bottleneck during post transfer printing. An attractive solution to address this challenge based on junctionless FETs (JLFETs), is investigated in this thesis via technology computer-aided design (TCAD) simulation and practical fabrication. The TCAD optimization implies a current of 3.36 mA for a 15 μm channel length, 40 μm channel width with an on-to-off ratio of 4.02x 107. Similar to the NRs, NWs are also suitable for realizing high performance e-skin. NWs of various sizes, distribution and length have been fabricated using various nano-patterning methods followed by metal assisted chemical etching (MACE). Synthesis of Si NWs of diameter as low as 10 nm and of aspect ratio more than 200:1 was achieved. Apart from Si NWs, V2O5 and ZnO NWs were also explored for sensor applications. Two approaches were investigated for printing NWs on flexible substrates namely (i) contact printing and (ii) large-area dielectrophoresis (DEP) assisted transfer printing. Both approaches were used to realize electronic layers with high NW density. The former approach resulted in 7 NWs/μm for bottom-up ZnO and 3 NWs/μm for top-down Si NWs while the latter approach resulted in 7 NWs/μm with simultaneous assembly on 30x30 electrode patterns in a 3 cm x 3 cm area. The contact-printing system was used to fabricate ZnO and Si NW-based ultraviolet (UV) photodetectors (PDs) with a Wheatstone bridge (WB) configuration. The assembled V2O5 NWs were used to realize temperature sensors with sensitivity of 0.03% /K. The sensor arrays are suitable for tactile e-skin application. While the above focuses on realizing conventional sensing and addressing elements for e-skin, processing of a large amount of data from e-skin has remained a challenge, especially in the case of large area skin. A Neural NW Field Effect Transistors (υ-NWFETs) based hardware-implementable neural network (HNN) approach for tactile data processing in e-skin is presented in the final part of this thesis. The concept is evaluated by interfacing with a fabricated kirigami-inspired e-skin. Apart from e-skin for prosthetics and robotics, the presented research will also be useful for obtaining high performance flexible circuits needed in many futuristic flexible electronics applications such as smart surgical tools, biosensors, implantable electronics/electroceuticals and flexible mobile phones

Engineering Dynamics and Life Sciences

From Preface: This is the fourteenth time when the conference “Dynamical Systems: Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the Committee of Mechanics of the Polish Academy of Sciences and Ministry of Science and Higher Education of Poland. It is a great pleasure that our invitation has been accepted by recording in the history of our conference number of people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcomed over 180 persons from 31 countries all over the world. They decided to share the results of their research and many years experiences in a discipline of dynamical systems by submitting many very interesting papers. This year, the DSTA Conference Proceedings were split into three volumes entitled “Dynamical Systems” with respective subtitles: Vibration, Control and Stability of Dynamical Systems; Mathematical and Numerical Aspects of Dynamical System Analysis and Engineering Dynamics and Life Sciences. Additionally, there will be also published two volumes of Springer Proceedings in Mathematics and Statistics entitled “Dynamical Systems in Theoretical Perspective” and “Dynamical Systems in Applications”