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With the aim of developing new solutions for powering pneumatic actuators in the field of wearable robotics, a principle scheme of a pressurized gas supply unit (GSU) based on hydrogen peroxide dec...

The introduction of intrinsic compliance in the actuation system of assistive robots improves safety and dynamical adaptability. Furthermore, in the case of wearable robots for gait assistance, the exploitation of conservative compliant elements as energy buffers can mimic the intrinsic dynamical properties of legs during locomotion. However, commercially available compliant components do not generally allow to meet the desired requirements in terms of admissible peak load, as typically required by gait assistance, while guaranteeing low stiffness and a compact and lightweight design. This paper presents a novel compact monolithic torsional spring to be used as the basic component of a modular compliant system for series elastic actuators. The spring, whose design was refined through an iterative FEA-based optimization process, has an external diameter of 85 mm, a thickness of 3 mm and a weight of 61.5 g. The spring, characterized using a custom dynamometric test bed, shows a linear torque versus angle characteristic. The compliant element has a stiffness of 98 N·m/rad and it is capable of withstanding a maximum torque of 7.68 N·m. A good agreement between simulated and experimental data were observed, with a maximum resultant error of 6%. By arranging a number of identical springs in series or in parallel, it is possible to render different torque versus angle characteristics, in order to match the specific applications requirements.

This paper describes the optimization of a planar wearable active orthosis for hip and knee assistance during overground walking. A non-anthropomorphic design is pursued in order to improve ergonomics and to reduce torque requirements. Based on a previously-developed systematic search algorithm of the admissible generalized solutions for the selected problem, a solution is selected and optimized by means of genetic algorithms and constrained non-linear optimization. The optimized design allows to conveniently redistribute mechanical power through different actuators, i.e. peak torque and velocity requirements for each actuator can be modulated, thus promoting a lighter design. A detailed analysis of the resulting mechanism workspace is carried out, including the evaluation of kinematic singularities, in order to verify the adequateness of the design in real-world scenarios. The developed model and optimization results are validated through a numerical analysis and experiments in a mock-up system.

Slip sensors are useful in robotics and prosthetics to improve the precision of force control during manipulation tasks. This work describes the design and fabrication of a flexible slip microsensor with no-moving parts, based on thermo-electrical phenomena. The sensor has been tested on a purposively developed test bench capable of producing a repeatable and controllable slip velocity. Experimental results are reported, demonstrating microsensor capability of discriminating slip events. The flexibility of the sensor makes it suitable for its integration on curved or deformable surfaces, such as robotic finger pads.

Computer-aided tissue engineering comprises a set of methodologies for the fabrication of prosthetic implants by means of rapid prototyping technologies. The paper presents a technique for the preparation of bioactive implants intended to be used in combination with mesenchymal stem cells for the regeneration of bone tissue. The methodology uses additive manufacturing of scaffolds according to a topological optimization algorithm and combines it with chemical functionalization protocols to increase material bioactivity.

In wearable robotics applications, actuators are required to satisfy strict constraints in terms of safety and controllability. The introduction of intrinsic compliance can help to meet both these requirements. However, the high torque and power necessary for robotic systems for gait assistance requires the use of custom elements, able to guarantee high performances with a compact and lightweight design. This paper presents a rotary Series Elastic Actuator (SEA), suitable to be used in an active orthosis for knee assistance during overground walking. The system includes a commercial flat brushless DC motor, a Harmonic Drive gear and a custom-designed torsion spring. Spring design has been optimized by means of an iterative FEM simulations-based process and can be directly connected to the output shaft, thus guaranteeing high torque fidelity. With a total weight of 1.8 kg, it is possible to directly include the actuator in the frame of a wearable orthosis for knee flexion/extension assistance. The presented design allows to obtain a large-force bandwidth of 5 Hz and to regulate output impedance in a range compatible to locomotion assistance of elderly subjects with an age-related decay of motor performances.

While the progress in imaging techniques more and more allows early and accurate diagnosis, minimally invasive intervention is still largely dependent on the availability of smart tools able to perform tasks inside the human body with a high level of autonomy. In this framework, endoscopic robots locomotion capabilities are needed to reach the site of interest, possibly with the desired orientation and with a firm grasping of the tissue. Current locomotion techniques do not provide sufficient degrees of mobility or are hardly miniaturizeable to the desired extent. In this paper we present the concept of a novel locomotion technique, called pinch locomotion, that relies upon and takes advantage of the large deformability of intestine to allow propulsion, steering and standing at a place with a continuous grasping of the tissue. The proposed locomotion technique is instantiated in a preliminary larger-scale prototype (70 mm×29 mm×10 mm), that is able to easily propel itself over a flexible stripe of cloth. The feasibility of a miniature endoscopic robot, endowed with the pinch-locomotion and with dimensions compatible to current swallable devices, is also investigated from a design perspective.

This paper describes the development of an autonomous robotic fish, meant to be used as an experimental platform for the validation of bio-inspired control architectures and sensory-motor coordination models. In its development, particular attention has been paid to the system architecture and the bio-mechatronic design in order to enable 3D swimming patterns, which can be planned taking into account the information flow generated by a rich sensory system. Also, attention has been paid to implement a versatile software architecture. Preliminary results about bio-inspired motion patterns generation and coordination are presented. This work lays the foundations for the development of bio-inspired underwater robots capable of complex behaviors, as required in search-and-rescue applications, as well as in exploration tasks.

Fully implantable Cochlear Implants (CIs) would represent a tremendous advancement in terms of quality of life, comfort and cosmetics, for patients with profound sensorineural deafness. One of the main challenges involved in the development of such implants consists of finding a power supply means which does not require recharging. To this aim an inertial Energy Harvester (EH), exploiting the kinetic energy produced by vertical movements of the head during walking, has been investigated. Compared to existing devices, the EH needs to exploit very low frequency vibrations (

Novel compliant actuation systems have been developed in recent years for a variety of possible advantages, such as establishing a safe human–robot interaction, increasing energy efficiency, reducing the effects of impacts and even for the development of neuro-inspired robotic platforms to be used in human motor control studies. In this rapidly growing and transversal research field, systems involving more than one active element (typically motors) for each actuated degree of freedom are being investigated to allow separate position and impedance regulations. Considering the wide range of applications and the large number of different arrangements deriving from the combination of two active elements and passive elastic components, several actuation architectures have been devised. This paper reviews state-of-the-art rotary variable impedance units incorporating two separate motors. Existing devices are grouped in three main categories. A critical and comparative analysis of the most relevant features is carried out, also based on most representative prototypes. Recently proposed methodologies and evaluation criteria for design optimization are illustrated and perspectives on potential applications of double actuation systems are presented.

Computer-Aided Tissue Engineering (CATE) is based on a set of additive manufacturing techniques for the fabrication of patient-specific scaffolds, with geometries obtained from medical imaging. One of the main issues regarding the application of CATE concerns the definition of the internal architecture of the fabricated scaffolds, which, in turn, influences their porosity and mechanical strength. The present study envisages an innovative strategy for the fabrication of highly optimized structures, based on the a priori finite element analysis (FEA) of the physiological load set at the implant site. The resulting scaffold micro-architecture does not follow a regular geometrical pattern; on the contrary, it is based on the results of a numerical study. The algorithm was applied to a solid free-form fabrication process, using poly(e-caprolactone) as the starting material for the processing of additive manufactured structures. A simple and intuitive geometry was chosen as a proof-of-principle application, on which finite element simulations and mechanical testing were performed. Then, to demonstrate the capability in creating mechanically biomimetic structures, the proximal femur subjected to physiological loading conditions was considered and a construct fitting a femur head portion was designed and manufactured.

In the design of wearable robots that strictly interact with the human body and, in general, in any robotics application that involves the human component, the possibility of having modular joints able to produce a viscoelastic behaviour is very useful to achieve an efficient and safe human-robot interaction and to give rise to emergent dynamical behaviors. In this paper we propose the design of a compact, passive, rotary viscoelastic joint for assistive wearable robotics applications. The system integrates two functionally distinct sub-modules: one to render a desired torsional stiffness profile and the other to provide a desired torsional damping. Concepts and design choices regarding the overall architecture and the single components are presented and discussed. A viscoelastic model of the system has been developed and the design of the joint is presented.

The successful introduction of robotic technologies in the rehabilitation arena critically depends on the possibility to design machines able to operate in symbiosis with patients, i. e., adapting the level of assistance to their residual abilities. Safety, easiness of use, and flexibility are key factors for these systems, which typically operate in continuous physical contact with the human body.

Introduction: The kinematic structure of wearable robots designed for lower limb rehabilitation usually replicates that of the human body (anthropomorphism), thus kinematic incompatibilities may arise from the mismatch between robotic and human joint axes of rotation. Conversely, non-anthropomorphic structures can be designed to be robust against misalignments, thus minimizing undesired interaction forces [1]. A non-anthropomorphic treadmill-based robot for hip and knee flexion/extension assistance, using compliant actuators [2] and deriving human joint kinematic patterns with forward kinematics, has been previously presented [3] and [4]. Inaccuracies in the mapping of rotations from the robot joint space to the human joint space may arise from: (1) human segments length estimation errors, which affect the human–robot parallel kinematic chain, (2) non-rigid human–robot connections and (3) uncertainty associated to the position of fastening points. The aim of this work is to validate the human joints kinematics estimated by the robot (RK) using that provided by inertial measurement units (IK) as reference. Methods:Ahealthy subject (male, 28 y.o.) walked on a treadmill at 0.55, 0.7 and 0.85 m/s wearing the robot. Four inertial measurement units (IMUs – Xsens, MTX, sampling frequency 50 Hz) were attached to the pelvis, thigh, and shank cuffs and to the foot on the right side (Fig. 1). The RK of hip and knee were estimated from the encoders measurements (sampling frequency 200 Hz) using the third-order polynomial approximation of the forward kinematic function derived in [3]. At the beginning of each trial, while the subject was standing (reference configuration), thigh and shank IMUs were mathematically aligned to the pelvis IMU. Hip and knee IK were estimated in terms of sagittal components of the relevant orientation vectors provided by the IMUs. Gait cycles were identified using the acceleration peaks at heel strike. Data from the encoders and IMUs were synchronized using an external trigger. The root mean square deviation (RMSD) between hip and knee RK and IK was computed for the three trials over 10 gait cycles. Results: Representative patterns of hip and knee angles in the sagittal plane (treadmill velocity: 0.55 m/s) are reported. RMSD values averaged over the three different gait speeds were 2.9±0.2◦ for the hip and 4.9±1.2◦ for the knee (mean±sd). In all the trials, maximum discrepancies were found at the peak values (RK peak extension angles were overestimated). Discussion: Non-anthropomorphic robots can offer several advantages in terms of wearability but they may introduce some inaccuracies in the estimation of human joints kinematics. However, results showed that hip and knee RK errors were within levels acceptable in the majority of clinical applications. Moreover, the systematic errors observed can be corrected through a proper calibration of the robot-to-human mapping. The estimate of lower limb kinematics from IMUs integrated in the robotic cuffs could facilitate the control of the robot.

The choice of non-anthropomorphic kinematic solutions for wearable robots is motivated both by the necessity of improving the ergonomics of physical Human-Robot Interaction and by the chance of exploiting the intrinsic dynamical properties of the robotic structure so to improve its performances. Under these aspects, this new class of robotic solutions is potentially advantageous over the one of anthropomorphic robotic orthoses. However, the process of kinematic synthesis of non-anthropomorphic wearable robots can be too complex to be solved uniquely by relying on conventional synthesis methods, due to the large number of open design parameters. A systematic approach can be useful for this purpose, since it allows to obtain the complete list of independent kinematic solutions with desired properties. In this perspective, this paper presents a method, which allows to generalize the problem of kinematic synthesis of a non-anthropomorphic wearable robot for the assistance of a specified set of contiguous body segments. The methodology also includes two novel tests, specifically devised to solve the problem of enumeration of kinematic structures of wearable robots: the HR-isomorphism and the HR-degeneracy tests. This method has been implemented to derive the atlas of independent kinematic solutions suitable to be used for the kinematic design of a planar wearable robot for the lower limbs.

During manipulation tasks it is important to maintain a precise and safe control of the grasping force. Slip detection plays a key role to assure an adequate adaptation of the grasping force, without object damaging. Several approaches to slip detection are currently under investigation. In particular, thermal slip sensors use a detection strategy similar to the one employed in hot wire anemometry, using a microfabricated thermal probe for detecting the convective heat flux associated to the movement of the touched object. This paper reports on the model-based optimization of a thermal slip sensor, intended for robotic prosthesis. In particular, an analytical thermal model has been developed, by merging FEM and dimensional analysis. A sensitivity analysis, performed on the parameters appearing in the model, has been performed for optimizing both sensor's geometry and materials in order to increase the heat flux and thereby to obtain a reduction of response times in the identification of slip. Simulations on the proposed design indicate an expected increase of the thermal dissipated power of about 400%.

The choice of non-anthropomorphic kinematic solutions for wearable robots is motivated both by the necessity of improving the ergonomics of physical Human-Robot Interaction and by the chance of exploiting the intrinsic dynamical properties of the robotic structure for an optimal interaction with the human body. Under these aspects, this new class of robotic solutions is potentially advantageous over the one of anthropomorphic robotic orthoses. However, the process of kinematic synthesis of non-antrhopomorphic wearable robots is very complex and difficult to be tackled by human intuition and engineering insight alone. A systematic approach is more useful for this purpose, since it allows to obtain the number of independent kinematic solutions with desired properties. In this perspective, this paper presents a method which enables to list the possible kinematic solutions for wearable robotic orthoses, which generalize the set of solutions of the problem of kinematic synthesis of a non-anthropomorphic wearable robot. This method has been implemented to derive the atlas of topologies of robotic kinematic chains which can be employed to support a 1-DOF human joint.

The need for novel, high performance actuators felt in several fields of robotics, such as assistive or rehabilitative robotics, is not fully satisfied by current actuation means. This fosters an intense research on novel energy transduction methods. In particular, propellant-based chemical actuators, able to directly convert chemical energy into mechanical energy, appear very promising, although their potential in robotics has not yet been deeply investigated. This work focuses on H 2 O 2 , used as propellant for actuators. This chemical was first used in robotics, with excellent results, by Goldfarb and collaborators, in 2003. H 2 O 2 dissociation is strongly exothermic, which generates important design issues when the actuated machine operates in close proximity to the human body. In this paper it is shown that: 1) is possible to operate the decomposition process at acceptable temperature, by means of basic solutions of hydrogen peroxide; 2) for basic pH solutions, tin becomes an effective catalyst for H 2 O 2 dissociation. A kinetic model of H 2 O 2 dissociation in basic solutions is provided, that is in good agreement with experimental data. We show how the model can be used to gather the necessary information for the dimensioning of H 2 O 2 -based actuators.

Effective administration of chemotherapeutics to the brain is a difficult task because of several reasons, including the anatomic location and the presence of the brain-to-blood barrier. The socio-economic burden of the pathology, discussed in the first part of the paper, stimulates the development of specific drug delivery systems, briefly reviewed and critically evaluated in a future perspective. Special emphasis is given to a solution under development at University Campus Bio-Medico (UCBM), which is compared to alternative approaches proposed in literature. Eventually, a technological roadmap is outlined and the related potential socio-economic impact is briefly discussed.

The foreign body reaction that the neural tissue develops around an implanted electrode contributes to insulate the probe and enhances the electrical and mechanical mismatch. It is a complex interaction among cells and soluble mediators and the knowledge of this phenomenon can benefits of formal and analytical methods that characterize the mathematical models. This work offers a lumped component model, described by ordinary differential equations, that taking into account the main geometrical (size, shape, insertion angle) and chemical (coating surface) properties of the implant predict the thickness of the fibrotic capsule in a time frame when the reaction stabilizes. This tool allows to evaluate different hypothetical solutions for accounting the tissue-electrode mismatch.

Insects exhibit remarkable navigation capabilities that current control architectures are still far from successfully mimic and reproduce. In this chapter, we present the results of a study on conceptualizing insect/machine hybrid controllers for improving autonomy of exploratory vehicles. First, the different principally possible levels of interfacing between insect and machine are examined followed by a review of current approaches towards hybridity and enabling technologies. Based on the insights of this activity, we propose a double hybrid control architecture which hinges around the concept of "insect-in-a-cockpit." It integrates both biological/artificial (insect/robot) modules and deliberative/reactive behavior. The basic assumption is that "low-level" tasks are managed by the robot, while the "insect intelligence" is exploited whenever high-level problem solving and decision making is required. Both neural and natural interfacing have been considered to achieve robustness and redundancy of exchanged information.

Insects exhibit remarkable navigation capabilities that current control architectures are still far from successfully mimic and reproduce. In this chapter, we present the results of a study on conceptualizing insect/machine hybrid controllers for improving autonomy of exploratory vehicles. First, the different principally possible levels of interfacing between insect and machine are examined followed by a review of current approaches towards hybridity and enabling technologies. Based on the insights of this activity, we propose a double hybrid control architecture which hinges around the concept of "insect-in-a-cockpit." It integrates both biological/artificial (insect/robot) modules and deliberative/reactive behavior. The basic assumption is that "low-level" tasks are managed by the robot, while the "insect intelligence" is exploited whenever high-level problem solving and decision making is required. Both neural and natural interfacing have been considered to achieve robustness and redundancy of exchanged information.

User-teacher interaction during the learning and the execution of motor tasks requires the employment of various sensory channels, of which the tactile is one of the most natural and effective. In this paper we present a wearable robotic teacher for predefined motor tasks, consisting of a localization system and a wearable stimulation unit. This unit embeds four vibrotactile stimulators which are activated in order to provide the user with a feedback about the movement direction of the forearm in the cartesian space. Stimulators were chosen in order to maximize tactile sensitivity and spatial resolution. Tactile interface performances in guiding 2 DOF forearm movements were comparatively evaluated with two different sensory modalities: visual and visuotactile, by using a Virtual Reality (VR) rendering of the motor task. The comparison among sensory modalities was based on two movement indexes ad hoc defined: positioning accuracy and directionality of motor communication. The experimental tests have shown that the system described hereafter is a valuable tool for human motor motion guidance, allowing a successful and useful weighting of concurrent sensory inputs without providing relevant sensory interferences. Compared to visually-guided trajectories, positioning accuracy was improved in visuotactile-guided trajectories. The comparative analysis of the directionality index in all sensory modalities suggests that increasing the number of stimulators could improve the directionality of tactile motor communication.

This paper reports the preliminary results of a research effort aiming at conceptualizing novel insect/machine hybrid controllers for autonomous exploratory vehicles. In particular, we investigate the possibility to include pre-developed animal intelligence capable of sensory-motor integration, decision-making and learning behaviors. In this context we present an in-depth review of insect neurophysiology focussing on mechanisms related to navigation. In addition we critically review current approaches towards hybridity and insect/machine interfaces. Finally, a novel insect/machine hybrid control architecture is proposed. It includes biological/artificial modules and deliberative/reactive behaviors.

This paper presents the design criteria of a robot manipulator for the rehabilitation of the upper limb. The machine is conceived to optimize the dynamic behavior in the interaction with the patient, basically in terms of low impedance when back-driven and low and isotropic inertial properties. Robot kinematics and dynamics are mathematically modeled and its dynamic properties are measured in the workspace in terms of inertia and acceleration capabilities. A method is used that is borrowed from the literature and is based on inertia and acceleration graphical representation through ellipsoids.

This paper presents the design of a novel sensor for slip detection. It consists of an easily fabricated miniaturized thermal probe that senses the additional convective heat transfer associated with the occurrence of mechanical slip. The fabrication procedures and the operating principle for the device are described in detail. A simple experimental setup was used to test the effectiveness of the proposed device. Tests were performed with varying velocities on four materials of differing thermal properties and surface roughnesses. The results show that slip can be effectively detected by the proposed sensor with a response times which can be as low as 6.3 ms. The performance of the device can be further improved when used in conjunction with a separate pressure sensor and by using more accurate methods of electrical resistance measurement.

The closed-loop management of biological samples in#956;TAS requires proper flow-sensors to be inserted in the hydraulic path. The optimal choice between hybrid mounting and monolithic fabrication depends on several design variables, one of which is the technological compatibility between the sensor and the pumping mechanism. Monolithic integration appears to be the eligible solution if both pumps and sensors can be fabricated with the same technological process. In this paper we show that it is actually possible to fabricate a flow-sensor, based on streaming potential detection, with the same soft-lithographic process used for the fabrication of electroosmotic pumps. The device has been fabricated in PDMS and experimentally tested, showing a good linearity. Finally, its time-varying response, related to the aging of the PDMS surface, is discussed.

Mixing is one of the basic functions which automated lab-on-chips require for the effective management of liquid samples. In this paper we report on the working principle, design, fabrication and experimental characterization of a soft-lithographed micromixer for microfluidic applications. The device effectively mixes two liquids by means of chaotic advection obtained as an implementation of a Linked Twisted Map (LTM). In this sense it is chaotic. The liquids are electrokinetically displaced by generating rolls through AC electroosmosis on co-planar electrodes. The device performance has been tested on dyed DI-water for several voltages, frequencies and flow-rates, displaying good mixing properties in the range of $10 \div 100$kHz, at low peak-to-peak voltages ($\sim15 \div 20$ volts). Low voltage supply, small dimensions and possibility of fabrication via standard lithographic techniques make the device highly integrable in lab-on-a-chip platforms., Comment: 8 pages, 6 fihures

Recent research in the emerging field of phenomics aims at developing unobtrusive and ecological technologies which allow monitoring the behavior of infants and toddlers. Orientation tracking devices based on accelerometers and magnetometers represent a very promising technology since orientation in 3D space can be derived by solely relying upon the direction of the natural geomagnetic and gravitational fields which constitute an absolute coordinate frame of reference, i.e. sourceless. Many commercially available devices allow on-board calibration by means of addition of external circuitry, mainly used to generate artificial fields which act on the sensor itself as a known forcing input. Addition of external circuits is a major drawback in applications such as the one of interest, where the technology has to be worn by infants. When external fields, (e.g. gravitational and geomagnetic fields) are present, alternative calibration techniques are possible which rely on predefined orientation sequences of the sensor. In standard procedures, prior knowledge of the external field (magnitude and direction) as well as accuracy in performing the predefined orientation sequences contribute to determine the calibration parameters. In this work, a novel procedure for in-field calibration of magnetometric sensors is presented which does not rely on previous knowledge of magnitude and direction of the geomagnetic field and which does not require accurately predefined orientation sequences. Such a method proves especially useful in clinical applications since the clinician is no longer compelled to execute accurate calibration protocols

In the last few years mechatronic implantable drug delivery systems have been found to be suitable for a large variety of applications for the treatment of pathologies such as cancer, diabetes or neurological diseases. In particular, a large part of the aforementioned pathologies asks for direct drug delivery at brain level. Unfortunately, the field of biomechatronic systems fitted for a direct infusion of drugs into the brain is still in its infancy. In this paper, as a design starting point, we examine a conventional system for drug delivery against typical medical requirements for brain applications; then we try and define the architecture of a biomechatronic system for drug delivery into the cerebral compartment, taking into account the close interaction with the anatomical compartment and its physiological constraints. A model of the whole system is proposed, and some simulation results are given, together with a simple control strategy

The experimental investigation of the visco-elastic properties of the human arm has important implications in neuroscience, robotics and neuro-rehabilitation of the upper limb. In neuroscience it allows studying the mechanisms used by the central nervous system in implementing low-level strategies for motion control; in robotics it can provide useful information for the formulation of control strategies for human-robot interaction, by taking inspiration from the biological behavior; in neuro-rehabilitation it may be a useful tool for quantitatively assessing the recovery of motor functions during motor therapy. Few mechatronic instruments exist allowing the direct measurement of visco-elastic properties of the human arm. None of them are intended to be portable and stand-alone devices, and also to be properly interfaced with existing robots as end effectors. This paper is concerned with the design of a novel mechatronic handle intended to be a portable device for the measurement of human arm visco-elastic properties. The design specifications take into account also the possibility of adapting the device to existing robots for rehabilitation motor therapy. In particular, the investigation of existing literature, both in robotics and in neuroscience, together with numerical simulations, led to the selection of the most useful technical specifications for such devices. A preliminary design of the handle is also presented and discussed.

Movement and behavior analysis is a key research area in the domain of biomedical engineering and in many other medical research domains aiming at the understanding of physiological motor and cognitive basic mechanisms. The systematic application of robotic and mechatronic technologies to realize new tools and measurement methods for quantitatively assessing motor and cognitive functions in humans as well as in animal models is gaining an increasing popularity. This work represents a first step towards the development of a sensorised environment for behavioral phenotyping of animal models. In particular, this paper focuses on tremor analysis in reeler mice, an emerging potential animal model for anatomical and behavioral traits observed in autism. Ground reaction force (GRF) sensing is indeed the most direct means of measuring tremor. Although force platforms have extensively been used for large size animals, only few attempts have been made to measure GRF at a single paw for animals as small as mice or rats. Under the hypothesis that in-plane GRF components are directly connected to tremor, a small size, low-cost, 2-axis force sensor for measuring the in-plane components of GRF was designed and developed. Special care was paid to design a structure that would allow self-aligned assembly, for repeatability, and modularity for combining multiple platforms for a sensorised floor. Preliminarily testing was performed with both reeler and wildtype mice. Fourier analysis was deployed to extract information due to tremor, validating the hypothesis of a direct connection between tremor and in-plane GRFs.

In this paper we present a novel drug delivery device that: 1. is able to release drug in a controllable way (one shot, multiple shots, continuous release); 2. has power requirements compatible with those of standard integrated circuits; 3. can be easily miniaturized. The actuation principle relies on the electrolysis of a waterbased solution that is kept separated from the drug by an elastic membrane. The pressure generated inside the chamber containing the electrolytic solution causes an outward deflection of the membrane that forces the drug to exit its storing chamber through an outlet orifice. The drug out-flow can be electronically controlled and different releasing modes can be achieved (one shot, multiple shots, continuous delivery). Voltages as low as 2V are able to activate the device, with extremely small currents ( 1mA). A first prototype has been fabricated and tested. Flowrate and pressure vs. time measurements have been performed, which confirm the suitability of the device for in-body applications.

The growth of minimally invasive surgery and therapy (MIT and MIS) has generated strong need for smaller and smaller medical tools with enhanced diagnostic capabilities and high dexterity. The design of micromachines for MIS and MIT requires the application of criteria. of biomedical microengineering. It is not possible to simply scale down a macro-machine because we have to consider that the scaling laws of different forces have a different rate, thus changing their relative magnitude in the microdomain. As a consequence, common physical intuition has to be substituted or supported by theoretical modelling and numerical simulations. Biomedical micromachines have to strictly interact with the human body and the understanding of the biomechanical properties of tissues is of paramount importance for the appropriate design of a micromachine. In this paper, we outline some design concepts and present some physical cases of biomedical micromachines.

Various types of rigid and flexible endoscopes are used to inspect and to perform therapeutic procedures on different parts of the gastrointestinal (GI) tract. Due to the working characteristics of conventional endoscopes, most GI endoscopy procedures are unpleasant for the patient, and are technically demanding for the endoscopist. The authors are developing minirobots for semi-autonomous or autonomous locomotion in the GI tract. In this paper, the authors illustrate the systematic approach to the problem of “effective” locomotion in the GI tract and the critical analysis of “inchworm” locomotion devices, based on extensor and clamper mechanisms. The fundamentals of locomotion and the practical problems encountered during the development and the testing (in vitro and in vivo) of these devices are discussed. Finally, two mini-robots capable of propelling themselves in the colon and potentially suitable to perform rectum-sigmoidoscopy and colonoscopy are presented.

A number of micropumps have been proposed in the last few years based on different actuating principles and fabricated by different technologies, In most cases, however, those micropumps have been designed taking into account primarily available microfabrication technologies rather than appropriate fluidodynamic analysis, In fact, not many papers are available in the literature presenting theoretical models usable to describe the functioning and predict the performance of existing micropumps, In this paper we present a new theoretical model suitable for guiding the design and predicting the performance of a volumetric micropump actuated by a piezoelectric actuator. The model takes into account the influence of inlet and outlet parameters, fluid viscosity, pump geometry, and displacement of pumping element. Simulations have been performed and compared satisfactorily with results of experiments on a prototype micropump fabricated in our laboratory.

The authors are developing devices for semi-autonomous or autonomous locomotion in the gastrointestinal (GI) tract. In this paper, they illustrate the systematic approach to the problem of "effective" locomotion in the GI tract and the critical analysis of "inchworm" locomotion devices, based on extensor and clamper mechanisms. The fundamentals of locomotion and the practical problems encountered during the development and the testing (in vitro and in vivo) of these devices are discussed. A mini device capable of propelling itself in the colon and suitable to perform, at least, rectum-sigmoidoscopy (the tract where approximately 60% of all colon cancers are found) is presented. This paper introduces preliminary, but useful, concepts for understanding, modeling and improving the performance of virtually any existing and novel devices for endoscopy of the GI tract.

This paper presents a general approach to the problem of modelling membrane micropumps. The proposed approach is aimed at predicting the performance of a specific micropump versus the working frequency, according to its geometrical and mechanical characteristics. This can be very useful during the design process of microfluidic devices including several membrane micropumps connected in a complex layout. The developed model has been applied to the specific class of micropumps based on piezoelectric unimorph actuator and ball check valves. Model predictions agree with the experimental results obtained on prototypes made in the authors laboratory.

The last few years witnessed a remarkable development of microsystems for the life sciences. In particular, molecular and genomic analysis techniques underwent a tremendous development. After a focused review on these fields, it will be shown that most of the solutions proposed primarily aim at a higher level of automation for saving costs and time, while reducing the errors that may occur with manual methods. Some socio-economic considerations are also provided to sketch the potential market of such novel devices and a patent overview is presented. A future scenario, enabled by microtechnologies, is eventually provided.

Motivated by the interest that microelectrolytic systems are gaining in the development of the so-called lab-on-a-chip systems, i.e., miniature microfluidic devices for biochemical analysis, we present an analytical study of Ohmic conduction in rectangular charged microchannels filled with electrolytic solution. The study complements a previous one [M. Campisi et al., J. Chem. Phys. 123, 204724 (2005)], concerning ac electro-osmosis. The problem is framed within the theory of nonequilibrium thermodynamics and is based on the solution of the incompressible Navier-Stokes equation with an electrical body force due to the interaction of the applied electric field with the charged electric double layer (EDL) which forms at the solid-liquid interface. We analyze in detail the dependence of the system complex conductance on the ratio linear dimensions over Debye length with an eye on finite EDL effects, and compare its scaling properties with those of electrokinetic and hydraulic complex conductances.

Motivated by the growing interest in ac electroosmosis as a reliable no moving parts strategy to control fluid motion in microfluidic devices for biomedical applications, such as lab-on-a-chip, we study transient and steady-state electrokinetic phenomena (electroosmosis and streaming currents) in infinitely extended rectangular charged microchannels. With the aid of Fourier series and Laplace transforms we provide a general formal solution of the problem, which is used to study the time-dependent response to sudden ac applied voltage differences in case of finite electric double layer. The Debye-Huckel approximation has been adopted to allow for an algebraic solution of the Poisson-Boltzmann problem in Fourier space. We obtain the expressions of flow velocity profiles, flow rates, streaming currents, as well as expressions of the complex hydraulic and electrokinetic conductances. We analyze in detail the dependence of the electrokinetic conductance on the extension of linear dimensions relative to the Debye length, with an eye on finite electric double layer effects.

Cochlear implants (CIs) are used for compensating the so-called deep sensorineural deafness. CIs are usually powered by rechargeable or long-lasting batteries. In this paper, the feasibility of a fully implanted stand-alone device able to provide the electric power required for stimulating the auditory nerve, without external recharging, is investigated. At first, we demonstrate that the sound wave entering the ear is not a sufficient power source. Then, we propose a solution exploiting the mechanical energy associated to head vibration during walking. The energetic feasibility of this approach is demonstrated based on experimental measurements of head motions. Preliminary considerations on the technical feasibility of a fully implanted energy harvester are finally presented.

This paper describes an intensity-modulated fiber optic sensor for strain measurements. The sensing element is a polydimetilsiloxane (PDMS) micro-diffraction grating, 15 mm long, 2 mm thick, with channels 150 µm wide, spaced apart 200 µm. The working principle of the sensor can be summarized as follows: when the sensing element is strained perpendicularly to the grating plane, light passing through the grating undergoes a modulation caused by the phenomenon of diffraction. Since the grating is interposed between a laser source and a fiber optic, the coupled radiation intensity between these two optical elements can be considered as an indirect measure of strain. A static calibration of the measuring system has been performed, showing that the device, with measuring range of about 0.04, is capable to discriminate strain of 0.005 and it presents a sensitivity increase with strain in the whole range of measurements.

This work represents a first step towards the development of a sensorised environment for behavioral phenotyping of animal models. In particular, this paper focuses on tremor analysis in reeler mice, an emerging potential animal model for anatomical and behavioral traits observed in autism. Ground Reaction Force (GRF) sensing is indeed the most direct means of measuring tremor. Although force platforms have extensively been used for large size animals, only few attempts have been made to measure GRF at a single paw for animals as small as mice or rats. Under the hypothesis that in-plane GRF components are directly connected to tremor, a small size, low-cost, 2-axis force sensor for measuring the in-plane components of GRF was designed and developed. Special care was paid to allow self-aligned assembly for repeatability and modularity for combining multiple platforms for a sensorised floor. Preliminarily testing was performed with both reeler and wildtype mice. Fourier analysis was deployed to extract information due to tremor, validating the hypothesis of a direct connection between tremor and in-plane GRFs.

This paper presents a new biphasic electrofluidic rotary actuator relying on electrochemical mechanisms. Gas (H 2 and O 2 ) is generated at two platinum (Pt) electrodes, immersed in an electrolytic solution, when a low voltage, V, is applied to them. The generated gas pressurizes a closed elastomeric chamber, that deforms under the action of the applied pressure. The chamber is shaped so that no structural failure occurs and the desired output motion is produced, without any need for additional mechanical means such as motion converters. Simple thermodynamic considerations allow estimating the electromechanical coupling factors for the most common external loads.

Non-anthropomorphic wearable robots (WRs) give good grounds for expecting advantageous performances over traditional anthropomorphic solutions from both the standpoints of ergonomics and of the dynamical interaction with the human body.