Actuation Sequences Research Articles

A Novel Capsule-Delivered Enteric Drug-Injection Device for Delivery of Systemic Biologics: A Pilot Study in a Porcine Model.

Innovative swallowable capsule technologies such as drug-loaded, dissolvable microneedles, mucoadhesive patches, and various microdevices present unique drug-carrying capabilities to overcome challenges regarding oral delivery of biologics. Here, we report a swallowable capsule for intestinal drug delivery (SCIDD) with the potential of directly injecting biological therapeutics into the insensate small intestine wall. The design, optimization, and validation of the SCIDD's primary subsystems were performed both ex-vivo and in-vivo. The assembled capsule was further tested in vivo to validate the actuation sequence and showed a 70% (n = 17) success rate in an animal model. Additionally, a drug delivery study indicated systemic uptake of adalimumab via SCIDD compared with luminal delivery in the small intestine. The pilot study presented here establishes that the novel platform could be used to orally deliver systemic biologics.

SoMoGym: A Toolkit for Developing and Evaluating Controllers and Reinforcement Learning Algorithms for Soft Robots

Soft robotsoffer a host of benefits over traditional rigid robots, including inherent compliance that lets them passively adapt to variable environments and operate safely around humans and fragile objects. However, that same compliance makes it hard to use model-based methods in planning tasks requiring high precision or complex actuation sequences. Reinforcement learning (RL) can potentially find effective control policies, but training RL using physical soft robots is often infeasible, and training using simulations has had a high barrier to adoption. To accelerate research in control and RL for soft robotic systems, we introduce SoMoGym ( <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">So</u> ft <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Mo</u> tion <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Gym</u> ), a software toolkit that facilitates training and evaluating controllers for continuum robots. SoMoGym provides a set of benchmark tasks in which soft robots interact with various objects and environments. It allows evaluation of performance on these tasks for controllers of interest, and enables the use of RL to generate new controllers. Custom environments and robots can likewise be added easily. We provide and evaluate baseline RL policies for each of the benchmark tasks. These results show that SoMoGym enables the use of RL for continuum robots, a class of robots not covered by existing benchmarks, giving them the capability to autonomously solve tasks that were previously unattainable.

Analysis of climbing in circular and rectangular pipes with a reconfigurable sprawling robot

This paper presents an analytical description and experimental results for a reconfigurable field robot that can climb inside circular and rectangular pipes. The robot is fitted with two mechanisms that allow it to change its width and height and shift its center of mass (COM) to adapt itself to the size of the pipe. We start by describing the kinematic model of the robot as a function of its sprawl and four bar extension mechanism (FBEM). Next, we develop a force analysis based on the robot's geometry, its configuration, the position of its center of mass (COM), the diameter of the pipe, and the coefficient of friction (COF). We then develop strategies for driving, climbing and transitioning between the two modes. Although a high COF increases the robot's grip, it reduces its ability to reconfigure its shape, which it needs to transition between its climbing/driving modes. Based on this analysis, we designed a control algorithm comprised of actuation sequences to automatically drive the robot inside pipes, including the transition phases. The results show that the robot successfully executed its climbing tasks (see video).

A Survey on Security of Digital Microfluidic Biochips: Technology, Attack, and Defense

As an emerging lab-on-a-chip technology platform, digital microfluidic biochips (DMFBs) have been widely used for executing various laboratory procedures in biochemistry and biomedicine such as gene sequencing and near-patient diagnosis, with the advantages of low reagent consumption, high precision, and miniaturization and integration. With the ongoing rapid deployment of DMFBs, however, these devices are now facing serious and complicated security challenges that not only damage their functional integrity but also affect their system reliability. In this article, we present a systematic review of DMFB security, focusing on both the state-of-the-art attack and defense techniques. First, the overall security situation, the working principle, and the corresponding fabrication technology of DMFBs are introduced. Afterwards, existing attack approaches are divided into several categories and discussed in detail, including denial of service, intellectual property piracy, bioassay tampering, layout modification, actuation sequence tampering, concentration altering, parameter modification, reading forgery, and information leakage. To prevent biochips from being damaged by these attack behaviors, a number of defense measures have been proposed in recent years. Accordingly, we further classify these techniques into three categories according to their respective defense purposes, including confidentiality protection, integrity protection, and availability protection. These measures, to varying degrees, can provide effective protection for DMFBs. Finally, key trends and directions for future research that are related to the security of DMFBs are discussed from several aspects, e.g., manufacturing materials, biochip structure, and usage environment, thus providing new ideas for future biochip protection.

Modeling of Soft Pneumatic Actuators with Different Orientation Angles Using Echo State Networks for Irregular Time Series Data.

Modeling of soft robotics systems proves to be an extremely difficult task, due to the large deformation of the soft materials used to make such robots. Reliable and accurate models are necessary for the control task of these soft robots. In this paper, a data-driven approach using machine learning is presented to model the kinematics of Soft Pneumatic Actuators (SPAs). An Echo State Network (ESN) architecture is used to predict the SPA’s tip position in 3 axes. Initially, data from actual 3D printed SPAs is obtained to build a training dataset for the network. Irregular-intervals pressure inputs are used to drive the SPA in different actuation sequences. The network is then iteratively trained and optimized. The demonstrated method is shown to successfully model the complex non-linear behavior of the SPA, using only the control input without any feedback sensory data as additional input to the network. In addition, the ability of the network to estimate the kinematics of SPAs with different orientation angles is achieved. The ESN is compared to a Long Short-Term Memory (LSTM) network that is trained on the interpolated experimental data. Both networks are then tested on Finite Element Analysis (FEA) data for other angle SPAs not included in the training data. This methodology could offer a general approach to modeling SPAs with varying design parameters.

ANISMA: A Prototyping Toolkit to Explore Haptic Skin Deformation Applications Using Shape-Memory Alloys

We present ANISMA, a software and hardware toolkit to prototype on-skin haptic devices that generate skin deformation stimuli like pressure, stretch, and motion using shape-memory alloys (SMAs). Our toolkit embeds expert knowledge that makes SMA spring actuators more accessible to human–computer interaction (HCI) researchers. Using our software tool, users can design different actuator layouts, program their spatio-temporal actuation and preview the resulting deformation behavior to verify a design at an early stage. Our toolkit allows exporting the actuator layout and 3D printing it directly on skin adhesive. To test different actuation sequences on the skin, a user can connect the SMA actuators to our customized driver board and reprogram them using our visual programming interface. We report a technical analysis, verify the perceptibility of essential ANISMA skin deformation devices with 8 participants, and evaluate ANISMA regarding its usability and supported creativity with 12 HCI researchers in a creative design task.

Engineering Liquid-Vapor Phase Transition for Refreshable Haptic Interfaces.

Haptics as a communication medium has been increasingly emphasized across various disciplines. Recent efforts have focused on developing various haptic stimulation technologies; however, most of them suffer from critical drawbacks stemming from their bulk, complexity, large power input, or high cost. Here, we describe a strategy to design portable and affordable refreshable haptic interfaces composed of an array of individually addressable and controllable liquid pouch motor-based haptic units embedded in either rigid or flexible substrates for different application contexts. The pouch motor filled with low boiling fluid, under a controlled manner, expands or contracts by Joule heating or cooling, enabling the haptic pin in contact to be protruded or retracted. Programming the actuation sequence of an array of haptic units enables the haptic interface to apply different stimuli to the skin to convey corresponding information. We finally demonstrate the applications to portable rigid braille displays and flexible epidermal VR devices. This study opens the avenue to the design of ubiquitous refreshable haptic interfaces that is portable, affordable, scalable, and uninjurious.

Stability and Receptivity of the Swept-Wing Boundary-Layer Flow Controlled by a Periodic Sequence of Plasma Actuators

Stability and Receptivity of the Swept-Wing Boundary-Layer Flow Controlled by a Periodic Sequence of Plasma Actuators

A Framework for Validation of Synthesized MicroElectrode Dot Array Actuations for Digital Microfluidic Biochips

Digital Microfluidics is an emerging technology for automating laboratory procedures in biochemistry. With more and more complex biochemical protocols getting mapped to biochip devices and microfluidics receiving a wide adoption, it is becoming indispensable to develop automated tools and synthesis platforms that can enable a smooth transformation from complex cumbersome benchtop laboratory procedures to biochip execution. Given an informal/semi-formal assay description and a target microfluidic grid architecture on which the assay has to be implemented, a synthesis tool typically translates the high-level assay operations to low-level actuation sequences that can drive the assay realization on the grid. With more and more complex biochemical assay protocols being taken up for synthesis and biochips supporting a wider variety of operations (e.g., MicroElectrode Dot Arrays (MEDAs)), the task of assay synthesis is getting intricately complex. Errors in the synthesized assay descriptions may have undesirable consequences in assay operations, leading to unacceptable outcomes after execution on the biochips. In this work, we focus on the challenge of examining the correctness of synthesized protocol descriptions, before they are taken up for realization on a microfluidic biochip. In particular, we take up a protocol description synthesized for a MEDA biochip and adopt a formal analysis method to derive correctness proofs or a violation thereof, pointing to the exact operation in the erroneous translation. We present experimental results on a few bioassay protocols and show the utility of our framework for verifiable protocol synthesis.

Two-phase mixture formation in transport diesel engine: the control algorithm and the devise for its implementation

The article reviews the issues dedicated to improving of energy and environmental indicators of automotive machinery by means of two-phase mixture formation in diesel engine. With this method, the 1st phase of mixture formation proceeds at intake stroke by the supply of the certain dose of fuel activator (gasoline, alcohol, biodiesel, etc.) into engine intake manifold, where a mixture of air and activator is formed. The 2nd phase proceeds at compression stroke by the supply of the major dose of diesel oil with the standard fuel supply system into combustion chamber. For the practical implementation of the described method, the diesel engine needs to be equipped with an automatic system for fumigation of air charge. The system contains electronic control unit (ECU), electromagnetic injectors, electric pump and sensors of engine speed and load mode. An algorithm of ECU operation for program control of injectors, supplying activator at the intake stroke, was developed. The sequence of actuation of injectors, coincident with the engine firing order, was substantiated. A formula for calculation of the duration of control pulse supplied to the injectors was derived. The proposed automatic system performs the activator injection, corresponding to the engine firing order, and the exact activator dosage, depending on engine speed and load mode, at the 1st phase of two-phase mixture formation.

Selection of the optimal hydraulic drive for the press

The research presented in the article is devoted to the selection of the electric motor of the hydraulic press drive with a nominal force of 5MN. The article presents the main characteristics and the description of the press operation using the means of mechanization of the technological process of pressure treatment. Using the Deform-3D software package, the process of stamping the crosspiece of the ZIL-130 cardan shaft was simulated. Based on the presented hydraulic scheme of the press, its topological model was formed in the PA-9 software package. The deformation force obtained in the course of modeling the technological process of stamping was used in the topological model of the press. Using a tabular cyclogram, the sequence of actuation of the end switches and hydraulic distributors during the stamping process is shown. In the article, two variants of engine operation were analyzed. Based on the results of the conducted research, it is necessary to focus on the second version of the 55 kW engine, the operation of which will provide the required characteristics of the hydraulic drive of the press, which in turn will allow for technological stamping operations. The simulation tools allow providing estimated information when selecting the necessary tools to ensure the optimal characteristics of hydraulic press drives. The article considered the variation of electric motors that differ from each other in nominal characteristics, with constant characteristics of the pump. For more accurate estimates of energy savings during the operation of the hydraulic drive, it is necessary to vary the characteristics of the pump in the simulation, and the best option is to form an experiment planning matrix when combining the characteristics of the electric motor and the hydraulic pump. This approach ultimately allows forming a function for which one can select a hydraulic drive from existing brands of electric motors and hydraulic pumps for presses of the corresponding range of nominal force.

Defining relationships between geometry and behavior of bistable composite laminates

Bistability is exhibited by an object when it can be resting in two stable equilibrium states. Certain composite laminates exhibit bistability by having two stable curvatures of opposite sign with the two axes of curvature perpendicular to each other. These laminates can be actuated from one state to the other. The actuation from the original post-cure shape to the second shape is called as ‘snap-through’ and the reverse actuation is called as ‘snap-back’. This phenomenon can be used in applications for morphing structures, energy harvesting, and other applications where there is a conflicting requirement of a structure that is load-carrying, light, and shape-adaptable. MW Hyer first reported this phenomenon in his paper in 1981. He found that thin unsymmetric laminates do not behave according to the predictions of the Classical Lamination Theory (CLT). The CLT is a linear theory and predicts the post-cure shape of thin unsymmetric laminates to be a saddle. MW Hyer developed a non-linear method called the “Extended Classical Lamination Theory” which accurately predicted the laminate to have two cylindrical shapes. Since then, a number of researchers have tried to identify the key parameters affecting the behavior of such laminates. Geometric parameters such as stacking sequence, fibre orientation, cure cycle, boundary conditions, and force of actuation, have all been studied. The objective of this research is to define a relation between the length, width and thickness of square and rectangular laminates required to achieve bistability. Using these relations, a 36 in × 36 in bistable laminate is fabricated with a thickness of 30 CFRP layers. Also, it is proved that a laminate does not lose bistability with an increase in aspect ratio, as long as both sides of the rectangular laminate are above a certain ‘critical length’. A bistable laminate with dimensions of 2 in × 50 in is fabricated. Further, for laminates that are bistable, it is necessary to be able to predict the curvature and force required for actuation. Therefore, a method is developed which allows us to predict the curvature of both stable shapes, as well as the force of actuation of laminates for which the thickness and dimensions are known. Finite Element Analysis is used to carry out the numerical calculations, which are validated by fabricating laminates. The curvature of these laminates is measured using a profilometer and the force of actuation is recorded using a universal test set-up.

Security model for protecting intellectual property of state-of-the-art microfluidic biochips

Microfluidic biochips or lab-on-a-chip systems are controlled by the actuation sequences designed for some specific bioprotocols. Different attacks specifically, hardware Trojans in diagnostic kits like microfluidic biochips can jeopardize the healthcare industries. As the actuation sequence is also a piece of information, which can be altered by hardware Trojans, man-in-the-middle attacks, etc., it is essential to design a security model with some proper encryption techniques in order to make biochip designs trustworthy. Thus, in this paper, we present a security model for avoiding intellectual property theft of actuation sequences for microfluidic biochips in each stage of the biochip design flow. Furthermore, we describe systematic algorithms to minimize the time requirements for achieving the desired goals so that the chance of an attack is reduced, and hence, to enhance the security concerns of microfluidic biochips. Simulation results demonstrate that the proposed security model leads to maintain the time-to-result while not exceeding the completion time of different bioprotocols. The proposed scheme, which used AES as an encryption algorithm with a 128-bit encryption key, has also shown a speedup of 8.5 (with 88% efficiency) faster than the prior efficient scheme.

Metachronal waves in magnetic micro-robotic paddles for artificial cilia

Biological cilia generate fluid movement within viscosity-dominated environments using beating motions that break time-reversal symmetry. This creates a metachronal wave, which enhances flow efficiency. Artificially mimicking this behaviour could improve microfluidic point-of-care devices, since viscosity-dominated fluid dynamics impede fluid flow and mixing of reagents, limiting potential for multiplexing diagnostic tests. However, current biomimicry schemes require either variation in the hydrodynamic response across a cilia array or a complex magnetic anisotropy configuration to synchronise the actuation sequence with the driving field. Here, we show that simple modifications to the structural design introduce phase differences between individual actuators, leading to the spontaneous formation of metachronal waves. This generates flow speeds of up to 16 μm/s as far as 675 μm above the actuator plane. By introducing metachronal waves through lithographic structuring, large scale manufacture becomes feasible. Additionally, by demonstrating that metachronal waves emerge from non-uniformity in internal structural mechanics, we offer fresh insight into the mechanics of cilia coordination.

Development of PLC based Sequential Pneumatic Punching System

Programmable logic sequential pneumatic system is developed for mechanical applications, like sealing, name punching, plate designing, etc. punching machine is considered as inevitable in almost all the industries like mechanical, electronic, food industries and automobile, etc. To print the hallmarks, logos as a brand. In respect to reducing the processing time by upgrading the conventional system to automation by integrating with Programmable logic control (PLC) as the system works with the interfacing of hardware (punching machine) and solenoids to control the actuation sequence. A sequential pneumatic PLC-based automatic punching machine is designed to have great control over the process of punching the hallmarks and logos with an automating feeding system followed by the punching process, which leads to a high production rate and reduces the process lead time, and increases the safety of workers.

Boolean AND/OR mechanical logic using multi-plane mechanical metamaterials

In recent years, and with the continual development of additive manufacturing technologies, mechanical metamaterials have been explored for their programmable nature. This has opened a new design space into mechanical devices that utilise the structure of a material to perform a function, otherwise known as functional materials. Several examples of functional materials performing mechanical Boolean logic have been successfully demonstrated in the past. Previous designs were shown to have a limited number of gate configurations due to device operation occurring in a single plane. In this paper, a novel approach in performing AND and OR mechanical logic is successfully demonstrated. The proposed mechanical metamaterial controls the buckling response of a biased Von Mises Truss through actuation of anisotropic 3D unit cells to perform Boolean logic. It is shown, by changing the separation distance between unit cells, the functional material can behave as an AND/OR gate. Actuation of the unit cell changes the effective beam length of the bistable system, allowing a snap-through response to occur. By changing the orientation of the 3D unit cells, the input direction must also be considered for a snap-through response. The mechanical logic gates demonstrated are multi-plane, as the correct plane of actuation and input sequence are required for an output to occur.

Soft hopping and crawling robot for in-pipe traveling

Pipe inspection is of great importance from both safety and cost perspectives. Despite extensive research, in-pipe robots with multi-locomotion capability have not been fully explored. Here, we develop a multi-locomotion soft robot, with a compact yet robust structure, that can hop for speed and crawl for maneuverability in horizontal and vertical pipes for pipe inspection. The robot consists of two motors, cables, and several longitudinally arranged elastic ribbons. These ribbons, with strategically designed profiles, are 3D-printed and can be buckled into three-dimensional shapes by pulling cables, thereby achieving hopping and crawling (forward and backward) by issuing different actuation sequences and parameters of the two motors. We studied the effect of ribbon design and pulling/releasing duration on the hopping and crawling performance. Our findings may shed light on the development of in-pipe robots with new functionality and applications.

KryptoJelly: a jellyfish robot with confined, adjustable pre-stress, and easily replaceable shape memory alloy NiTi actuators

Exploring the world beneath the ocean has been a difficult task, especially in depths that are unsafe for humans. Studying underwater creatures can be very sensitive due to disturbances resulting from typical remotely operated vehicles (ROVs) currently used. Soft robots consist of elastomeric materials, compliant actuators, sensors and other supporting structures, which enable them to be used for numerous applications due to their flexibility, light weight, low noise, and many degrees of freedom. Mechanical actuators, such as pneumatic actuators and servomotors, introduce design constraints related to their size, weight, and cost. Moreover, vibration and noise are undesired attributes that preclude the use of robots developed with such technologies and might disturb the test environment. This paper presents a robust design of a jellyfish-like robot with eight bell segments, named KryptoJelly. The presented robot can perform multidirectional swimming by NiTi shape memory alloys (SMA) actuators confined in a conduit and activated by electrical current stimulation. KryptoJelly is constructed from a 3D printed rigid structure and a soft silicone bell that closely mimics the biological locomotion and appearance of a jellyfish found in nature; the Chrysaora colorata species. Four 127 μm diameter SMA wires (of mass 14 mg each) were used per channel to deform the silicone bell margin. The robot can operate up to 1608 cycles continuously for 1.5 h underwater at high power input (3 times higher than the standard) and sustain its own total body mass of 650 g (∼6000 times the weight of the actuators used). KryptoJelly is able to maneuver in both vertical and horizontal directions during bell contraction-expansion cycles. A study on the effect of multistage-power-time input sequence of NiTi SMA actuators and bell design, which results in swimming, is presented. This work has shown the great potential of employing smart materials in biomimetic soft robots, that can be deployed for eco-friendly underwater exploration or other applications.

Chip level design in MEDA based biochips: application of daisy chain based actuation

Recent advances in microfluidics and micro-fabrication technology enabled the emergence of a new microelectrode-dot-array (MEDA) architecture for microfluidic biochips. The MEDA based design facilitates dynamic routing with variable sized droplets having advanced characteristics such as field programmability, higher level of reconfigurability and scalability. Unlike traditional digital microfluidic biochips, droplet actuations for MEDA based biochips are accomplished through a daisy chain based interconnection of the microelectrodes. This paper provides a detail analysis of daisy chain configuration for different conditions e.g. manipulation of single droplets as well as manipulation of multiple droplets. A daisy chain control sequence for actuation has been proposed in order to evade droplet interference. This paper also defines different actuation sequences for a set of fundamental microfluidic operations namely droplet merging, mixing, splitting and transportation essential for bioassay execution. Finally a daisy chain actuation sequence for overall execution of a specified bioassay from sample preparation to chip level design are demonstrated. Experimental results figure out the daisy chain actuation time for implementation of standard test benches.

Elastic Energy Storage Enables Rapid and Programmable Actuation in Soft Machines

AbstractStorage of elastic energy is key to increasing the efficiency, speed, and power output of many biological systems. This paper describes a simple design strategy for the rapid fabrication of prestressed soft actuators (PSAs), exploiting elastic energy storage to enhance the capabilities of soft robots. The elastic energy that PSAs store in their prestressed elastomeric layer enables the fabrication of grippers capable of zero‐power holding up to 100 times their weight and perching upside down from angles of up to 116°. The direction and magnitude of the force used to prestress the elastomeric layer can be controlled not only to define the final shape of the PSA but also to program its actuation sequence. Additionally, the release of the elastic energy stored by PSAs causes their high‐speed recovery (≈50 ms), which significantly improves the actuation rates of soft pneumatic actuators, especially after motions requiring large deformations. Moreover, judicious prestressing of PSAs can also create bistable soft robotic systems, which use their stored elastic energy as a source of power amplification for rapid movements. These strategies serve as a basis for a new class of entirely soft robots capable of recreating bioinspired high‐powered and high‐speed motions using stored elastic energy.