External Control Unit Research Articles

Nine level switched capacitor inverter with level shifted pulse width modulation approach

This article proposes a nine-level switched capacitor inverter (NLSCI) with a minimum number of switches. In recent years, switching capacitor (SC) multilevel inverters (MLIs) have become one of the most common inverter topologies. These proposed nine level switched capacitor inverter (NLSCI) do not deserve any external control unit for capacitor control. Since, the charging and discharging of the capacitors are controlled by the on and off states of switches. Furthermore, by employing fewer switches and DC voltage sources, the suggested design produces a greater amount of resultant voltage. Additionally, pulse width modulation (PWM) is recommended as a method to enhance output quality and power level quality. The switched-capacitor two-output multilevel inverter (SCMLI) structure's viability and effectiveness have been demonstrated using MATLAB simulation.

Design and characterization of a 3D printed miniature actuator using shape memory alloy wires

Microfluidics has been at the center of attention in chemical and biological sciences over the last decade since it can miniaturize many laboratory-based applications. However, the transition from concept to a practical microfluidic chip is greatly hindered due to the widespread conventional soft lithography techniques which are used for the fabrication of the microfluidic chips. These methods are not time- and cost-efficient. Additive manufacturing technique (i.e. 3D printing) has grown in many research fields. Many conventional microfluidic system component designs have been adapted to the 3D printing manufacturing techniques. Three-dimensional printed active components such as microvalves and micropumps have also been studied, however, almost all the designs depend on an external pneumatic control unit or syringe pumps so far. In this study, we aimed to address the lack of a microfluidic active component with an integrated actuator unit. We used a shape memory alloy as the actuator. In doing so, we employed an innovative batch fabrication method that utilizes 3D printing. The proposed actuator design can produce high work and concurrently isolate the heat source from the fluidic sample which is of utmost importance for biological samples. The results show that the miniature actuator can block high pressure (up to 150 mmHg) silicone channel partially or completely depending on the application requirements. The actuation time can be controlled electronically and reduced to times as low as 100 ms. In conclusion, this design proved to be a promising candidate for the development of flow control components such as microvalves, micropumps, or micromixers.

Biosensors in cardiology. T-CARE project: a preliminary study on an innovative wearable telemonitoring system

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): REGIONE PUGLIA Introduction The demographic trend evolution and the modification of health needs highlight the requirement for a novel organization of the healthcare system. Telemedicine allows the assistance of patients remotely, breaking down geographical barriers. Purpose The aim of the present study was to assess the validity of a novel wearable system to monitor EKG, heart rate and pulse oximetry in patients with chronic cardiac diseases. The equippement included a T-shirt with electrodes and a band with a photopletimosgraphic sensor, connected to a tiny dock station (Figure 1, panel A). Methods We enrolled 38 patients admitted to the coronary care unit at our hospital in Italy, 71% male, mean age 67 years, mean EF 45%. The main characteristics of the sample are listed in Table 1. The system was entirely automatic. Health parameters recording started as soon as patients wore T-shirt and band. Data were transmitted by Bluetooth technology to an external control unit. Recordings could be stored or could be checked in real time from a control room. Data were compared to measurements obtained by traditional monitoring system (telemetry). Results The devices tested in this study showed a satisfying level of reliability in monitoring heart rate, pulse oximetry, QT interval, QRS complex duration, and onset of arrhythmic events. Indeed, the difference between traditional monitoring system and the new wearable equipment in acquiring health parameters was not statistically significant (Figure 1, panel B). However, alerts produced by arrhythmias different from atrial fibrillation were not completely reliable. Conclusions The most important aspect of this new equipment was the need of minimal patient’s interaction. This system was not inferior to traditional telemetry in recording health parameters.

THE DEVELOPMENT OF INTERNAL FINANCIAL CONTROL MECHANISMS IN THE HEALTH CARE INSTITUTION

The article reveals the development of internal financial control mechanisms, which is considered in conjunction with the use of planning tools, budgeting based on performance monitoring, along with the involvement of financial instruments leasing, factoring, outsourcing, which are important means of solving financial and production problems faced by the institution. The authors emphasize that one of the main tasks of financial control is not only strict compliance with the legality and legitimacy of spending budgetary financial resources, but also the search for effective mechanisms for managing them in market conditions, along with the development of market management tools, the search for additional extrabudgetary resources and sources of their replenishment, taking into account their rational use in conditions of growing competition in the open market of medical services. The article analyzes the system of internal financial control, which is able to increase the efficiency of the organization and is able to make higher demands on the budgetary powers of its controlling agency. It is assumed that the system of internal financial control is designed to take into account the areas and requirements in anticipating the reduction of budget subsidies, paying attention to the crisis and recessions in the formation of an open market for medical services in order to comply with the timeliness and quality of budget tasks and eliminate irrational or inappropriate use of budget resources. In order to successfully implement the tasks set by the new system of financial control, a new structure of internal financial control bodies has been developed, which is a permanently functioning, multifaceted system of bodies aimed at organizing monitoring, analysis, evaluation and timely control, carried out within the framework of a rational combination of powers of internal and external financial control units, which contributes to the timely elimination of identified shortcomings in the field of legality, legitimacy, efficiency and rational use of budgetary and extrabudgetary resources.

Swaying gel: chemo-mechanical self-oscillation based on dynamic buckling

<h2>Summary</h2> Self-oscillating systems are powerful tools for transducing static energy inputs into repetitive motions without the aid of external control units. The challenge in sustaining the far-from-equilibrium motion of an oscillating material is to avoid the tendency of reaching thermodynamic equilibrium or get pinned at steady states in the dynamic process. While living organisms present elegant strategies in myriad self-oscillations (e.g<i>.</i>, peristalsis, cilia motion, homeostasis), current synthetic self-oscillating systems often rely on a fast actuation/reaction, to maintain the far-from-equilibrium motion, which prescribe highly specific chemical reactions and a material microstructure with limited stimuli and movement modes. Here, we present a dynamic buckling-based design for creating self-oscillating systems. The oscillation arises from the self-driven snap-through of a responsive hydrogel between bi-/multi-stable buckling configurations governed by a feedback loop. With broad choices of materials, tunable mechanics, and physical simplicity, this system opens a new venue for unlimited autonomous-oscillating materials applications.

Investigation of three-dimensional vibration measurement by three scanning laser Doppler vibrometers in a continuously and synchronously scanning mode

This paper presents for the first time an investigation of three-dimensional (3D) vibration measurement by three scanning laser Doppler vibrometers (SLDVs) in a continuously and synchronously scanning mode. Three laser spots from the three SLDVs continuously move along the same scan trajectory and synchronously measure vibration of the same point on a surface of a structure. The three SLDVs, i.e., Top, Left, and Right SLDVs, are from a Polytec PSV-500-3D system and input signals to scan mirrors of each SLDV are controlled by an external dSPACE MicroLabBox control unit. The whole system is called a 3D continuously SLDV (3D-CSLDV) system. Methodologies are developed in this investigation to achieve the continuously and synchronously scanning mode by the system. First, the geometrical model of a CSLDV is built to obtain locations of the three CSLDVs with respect to a specified measurement coordinate system (MCS). Second, a scan trajectory on the measured surface is defined and rotation angles of scan mirrors of the Top CSLDV are obtained by scanning the trajectory. Third, since locations of the three CSLDVs with respect to the MCS have been obtained in the first step, rotation angles of scan mirrors of Left and Right CSLDVs to scan the defined trajectory can be obtained from those of the Top CSLDV based on spatial relations among the three CSLDVs. Experiments to scan a beam and a plate were conducted using the 3D-CSLDV system. Operating deflection shapes (ODSs) of the beam and plate in three directions of the MCS were obtained and they were in good agreement with those obtained by traditional step scanning. The results demonstrate the feasibility of 3D vibration measurement by the 3D-CSLDV system in a continuously and synchronously scanning mode.

Design of a Compact Dual-Band Antenna for On-/Off Body Communication

In this paper, a compact, dual-band, patch antenna structure for body-centric relay node communication is presented. The antenna is designed to operate at Industrial, Scientific and Medical (ISM) bands at 2.45 GHz for receiving data from intra-body sensor nodes and 5.0 GHz for transmitting signal to external monitoring device. The antenna is designed by using coplanar waveguide feed and etching two open-end slots on radiating patch. Overall antenna dimensions are 15 mm × 28 mm × 1.57 mm. Effective dielectric constant for the multiple dielectric layers, due to its heterogeneous tissue structure, has been calculated. Antenna performance is measured both in free space and on tissue model. On body, a wide bandwidth of 250 and 370 MHz is obtained that enhances antenna robustness to operate on different types of body tissues. Radiation pattern toward the surface of body at 2.45 GHz and directional pattern normal to the surface of body at 5.0 GHz are achieved. High directivity of 7.18 dBi at 5.0 GHz is obtained which is good to maintain robust communication link with the external control unit. Small size, good radiation characteristics and low SAR value make the antenna a good choice for operating in close proximity to human body.

MRI after successful eyeWatchTM implantation

The eyeWatchTM is a new glaucoma drainage device that includes an adjustable mechanism that can vary the resistance to aqueous humor outflow during the postoperative period to reduce the burden of postoperative intraocular pressure (IOP) management. The mechanism contains a magnetic rotor that can be adjusted using an external magnetic control unit. Adjustments of the position of the rotor are performed mostly in the initial postoperative follow-up period in order to reach the target IOP. However, for some patients, it might be necessary to perform MRI for the sake of medical investigations. As the MRI is creating a strong magnetic field, this magnetic field is likely to interact with the adjustable rotor of the eyeWatchTM, resulting in modification of the IOP. We report the case of an 82-old female patient successfully operated with the implantation of an eyeWatchTM. The patient underwent a cerebral MRI for persistent headache. Shortly after the MRI procedure, the patient was checked at the eye clinic to assess the position of the rotor and to measure the IOP. The eyeWatchTM was readjusted to the former position set before undergoing the MRI. No complications were reported in the follow-up after MRI. This case demonstrates that MRI examinations can be safely performed after glaucoma surgery using an eyeWatchTM without compromising on the quality of the imaging or the stability of the IOP. This is a complication-free procedure that only requires checking the new position of the rotor and re-adjusting the implant, if necessary, to achieve the target IOP.

EyeWatch™ System Combined with Non-plated Intraorbital Tube Insertion for the Management of Refractory Glaucoma: A Case Series.

IntroductionThe eyeWatch™ is a novel device in glaucoma surgery aiming at the control of aqueous flow through the use of an external magnetic control unit. We propose the modification of this approach through the use of an injectable perforated tube rather than a plated valve.Materials and methodsProcedures were performed at the Department of Ophthalmology of the University of Crete. Three blind painful eyes of three patients were included. All patients were operated under topical anesthesia. A purpose designed blunt-ended injector was used to insert intraorbitally a perforated 4 cm-long silicone tube. The tube was then connected to an eyeWatch™ device which was placed in a standard fashion along the superior–temporal quadrant of the eyeball. The procedure was uneventful in cases I and II, whereas in case III the tube had to be trimmed by 1.5 cm because of cicatricial changes in the orbit. The eyeWatch™ was left closed (position VI) at the conclusion of surgeries. Patients were examined on the 1-day, 1-week, 2-week, 1-month, 3-month, and 6-month intervals and in one case on the 12-month interval.ResultsNo major complications were observed. The intraocular pressure (IOP) remained under 15 mm Hg without anti-glaucomatous medications in all postoperative intervals in cases I and 2 with readjustment of eyeWatch™ at position IV. In case III, despite the change of the eyeWatch™ to the open position, the IOP remained high (40 mm Hg).DiscussionThe combination of the eyeWatch™ with an insertable perforated tube instead of a standard non-valved plate may prove a valid minimally invasive option. Modifications of the technique, such as an increased number and diameter of tube perforations, increased inserted tube length, perhaps aided by a sharp-ended injector, and selection of the insertion quadrant, may increase the effectiveness of the method.Clinical significanceeyeWatch™ combined with a single tube instead of a plated valve is a feasible, quick, and minimally invasive technique that can be used in glaucoma surgery.How to cite this articleDetorakis ET, Villamarin A, Roy S, et al. eyeWatch™ System Combined with Non-plated Intraorbital Tube Insertion for the Management of Refractory Glaucoma: A Case Series. J Curr Glaucoma Pract 2020;14(2):64–67.

An integrated opto-mechatronic system for self-calibration of accelerometer in large dynamic range

Long-term instability and scale factor drift are inherent problems in micro inertial measurement units (MIMU) such as accelerometers. This research achieves a novel integrated opto-mechatronic system of less than 1.6 cm3, containing an advanced six degree-of-freedom (DOF) piezoelectric microvibrator, a commercial micro-accelerometer and an optical displacement sensing system. In the integrated opto-mechatronic system, the piezoelectric microvibrator is the source of standard acceleration for self-calibration. It is capable of providing an acceleration of up to 30 g and an angular velocity of 1100°/s. The optical sensing system is applied to detect the real-time acceleration of the microvibrator to provide detection data for self-calibration. Moreover, the optical sensing system also self-detects and self-adjusts the output acceleration of the microvibrator. The external control and processing unit calculates the error coefficient of the accelerometer to obtain the compensation model to achieve self-calibration, according to the acceleration detected from the optical sensing system and the acceleration output from the accelerometer. The experimental results show that the output accuracy of the micro accelerometer is significantly improved after a complete self-calibration process from 0 to 24 g acceleration range.

Method for the Computer-Aided Schematic Design and Simulation of Hydrogel-Based Microfluidic Systems

We present an approach to the schematic design and time-dependent simulation of microfluidic systems that are composed of basic components, such as pumps, channels, mixing junctions, and valves. For the schematic capture and the simulation, the Cadence Virtuoso design framework is employed, with the components modeled by Verilog-AMS. The pressures and flow rates are calculated with the help of the hydraulic analogy between electronics and fluidics. Signal flow quantities are used to express the flow of chemical concentration. Our focus is on systems employing chemofluidic transistors, i.e., hydrogel-based microvalves that facilitate autonomous flow control without the need for an external control unit. Our approach also covers layout editing by the use of programmed cells. The utility of the approach is exemplified by the successful top-down design of a chemofluidic oscillator circuit and by the functionally correct simulation of a chemofluidic SR flip-flop.

Reference-Less Time-Division Duplex Transceiver IC for a Renal Denervation System

This paper presents the first time-division duplex transceiver integrated circuit (IC) for a 5 Fr (1.6 mm), six-electrode renal denervation (RDN) catheter for treating resistant hypertension. The diameter of the resulting RDN catheter, with each IC encapsulated in a platinum electrode, is 37.5% smaller than those of conventional catheters, enabling minimally invasive surgery with reduced complications. The six electrodes sharing only four electrical wires perform packet communication with an external power control unit for independent operation and deliver the designated radio-frequency (RF) energy to the renal artery wall while measuring the local temperature and impedance. The measured 3 $\sigma $ inaccuracy of a bipolar junction transistor (BJT)-based on-chip temperature sensor from 65 °C to 75 °C is ±0.5 °C after one-point trimming. Two 500-kHz, 21-Vrms ac signals with ±35-V dc potentials are used as power supplies to transfer up to 6-W RF ablation signals with 120-Vpp swing while keeping the maximum dc supply voltages of the ICs less than the breakdown voltage of 70 V. The proposed RDN IC fabricated using a 0.18- $\mu \text{m}$ high-voltage bipolar, CMOS, LDMOS (HV BCDMOS) occupies an area of 2.1 mm2.

Batch Assembly of SU-8 Movable Components in Channel Under Mild Conditions for Dynamic Microsystems:Application to Biohybrid Systems

Movable components in a microchannel are expected to develop dynamic microfluidics and new microfluidic applications. Biological motors are promising for the removal of external control units and provision of autonomy to microsystems. However, these components in a microchannel have not been widely used because of the lack of an easy-to-use method. This paper reports first the batch assembly of movable components in a microchannel under mild conditions for dynamic microsystems and second, an integration with biological motors, Vorticella . We studied the pattern formation of dextran film with different shapes to use it as a sacrificial layer. Photopolymer components were fabricated on a patterned dextran film and then a polymer component on a dextran film was directly assembled in a microfluidic chip. An injection of water dissolved the dextran and transported a movable component by a fluid force. This fabrication process was further applied to demonstrate the motion conversion of a movable component by Vorticella . Cells of Vorticella were patterned around magnetic blocks in a microchannel using a magnetic force. Finally, a movable component was integrated with Vorticella to convert its motion. Our developed technologies open the possibility of fabricating a wide range of dynamic microsystems.

Momentum

Recent research has looked to supplement or even replace the batteries in embedded computing systems with energy harvesting, where energy is derived from the device’s environment. However, such supplies are generally unpredictable and highly variable, and hence systems typically incorporate large external energy buffers (e.g., supercapacitors) to sustain computation; however, these pose environmental issues and increase system size and cost. This article proposes Momentum , a general power-neutral methodology, with intrinsic system-wide maximum power point tracking, that can be applied to a wide range of different computing systems, where the system dynamically scales its performance (and hence power consumption) to optimize computational progress depending on the power availability. Momentum enables the system to operate around an efficient operating voltage, maximizing forward application execution, without adding any external tracking or control units. This methodology combines at runtime (1) a hierarchical control strategy that utilizes available power management controls (such as dynamic voltage and frequency scaling, and core hot-plugging) to achieve efficient power-neutral operation; (2) a software-based maximum power point tracking scheme (unlike existing approaches, this does not require any additional hardware), which adapts the system power consumption so that it can work at the optimal operating voltage, considering the efficiency of the entire system rather than just the energy harvester; and (3) experimental validation on two different scales of computing system: a low power microcontroller (operating from the already-present 4.7μF decoupling capacitance) and a multi-processor system-on-chip (operating from 15.4mF added capacitance). Experimental results from both a controlled supply and energy harvesting source show that Momentum operates correctly on both platforms and exhibits improvements in forward application execution of up to 11% when compared to existing power-neutral approaches and 46% compared to existing static approaches.

Comparative Case Study on the Self-Powered Synchronous Switching Harvesting Circuits With BJT or MOSFET Switches

Self-powered realization for synchronous switching circuits is a hot spot for piezoelectric vibration energy harvesting. Two typical kinds of switches, bipolar junction transistor (BJT) or metal–oxide semiconductor field effect transistor (MOSFET) are popularly used without a clear understanding about the performance difference. In this paper, comparative investigations about adopting these two types of switches based on a case study are performed. It is determined that the performance difference comes from three aspects: the gate parasitic capacitance, the turning-on threshold, and the driven mechanism. In particular, the third one imposes a critical influence on the performance. Investigations are performed on the self-powered synchronous switching circuit of two possible methods: with electronic breakers or with external control units. The results from simulations and experiments show that the current-driven mechanism limits the available performance in the case of the BJT switch in comparison with the case of the MOSFET switch. The difference is especially obvious for the cases of large piezoelectric capacitance and open-circuit voltage. A preliminary design guideline is concluded that the MOSFET is probably a better choice with the same voltage and current ratings in most cases.

Fine orientation control of an insertable robotic camera system for single incision laparoscopic surgery.

Insertable laparoscopic camera systems were developed to improve the minimally invasive surgeries. Robotic degrees of freedom for an insertable laparoscopic camera are required to adjust the camera's orientation and position inside an abdominal cavity. This paper demonstrates an insertable magnetic actuated robotic camera system with two-degree-of-freedom (2-DoF) orientation control for single incision laparoscopic surgery. The camera system design consists of an external magnetic control unit and a fully insertable camera capsule. This system features a unified mechanism for anchoring, navigating, and rotating the insertable camera capsule by externally generated rotational magnetic field from the control unit. The motor-free camera capsule is encapsulated in an one-piece housing with two ring-shaped tail-end magnets and one cylindrical central magnet. The control unit that positioned externally consists of both permanent magnets and electromagnetic coils to generate rotational magnetic field and control the camera capsule. The experimental investigations indicated that the camera control system can achieve less than 1° control accuracies with average errors 0.594° and 0.524° for tilt motion and pan motion, respectively. The designed control system provides fine orientation control for the insertable camera capsule which guarantees proper vision for the surgeon during single incision laparoscopic surgery.

Interactive implants: vision and challenges

Abstract Different complex physiological functions might be restored by means of distributed active implants. Wireless communication between the implants, on the one hand, and an external control unit, on the other hand, is necessary to synchronize electrical stimulation of neural and muscular tissue. Seventeen project partners from industries, universities, healthcare providers and research organizations closely cooperate in the framework of the BMBF Innovation Cluster “Interactive Implants (INTAKT)”. The goal of this cluster is to develop and evaluate networks of distributed implants. Challenges of the project include complex interaction between humans and technology, wireless power supply, long-term stability of implants as well as secure and safe signal transmission [1].

Experiment of selective catalytic reduction retrofit for euro 6 NOx emission level compliance for euro 5 light duty vehicle

An independently developed retrofit selective catalytic reduction (SCR) system was implemented onto a Euro 5 light duty vehicle, in order to comply with the Euro 6 nitrogen oxides (NOx) limit over the legislative laboratory cycle. The SCR catalytic converter was fitted to the existing exhaust line, downstream of the diesel oxidation catalyst and the particle filter. The urea dosing system, including NOx sensors, was set up onboard the vehicle in order to catalytically treat the exhaust gas and effectively reduce NOx. The urea injection strategy was managed by an external dosing control unit, while the engine calibration was not modified and remained at the Euro 5 level. The legislative tests were performed in an emission laboratory on the chassis dynamometer installed in a climatic chamber. The reference emission level of the unmodified vehicle and aftertreatment layout was established. Following SCR retrofitting process, the emission cycles were repeated, and the results obtained were compared. The SCR system effectiveness was found to be in a close correlation with exhaust gas temperature.The presented test results gave an insight into the possibility of significant NOx reduction in modern light duty vehicles by means of usage of an add-on type of NOx catalytic reduction system, without modifications to the engine control unit.

Mechatronic design and genetic-algorithm-based MIMO fuzzy control of adjustable-stiffness tendon-driven robot finger

Abstract. This work presents a detailed design of a three-jointed tendon-driven robot finger with a cam/pulleys transmission and joint Variable Stiffness Actuator (VSA). The finger motion configuration is obtained by deriving the cam/pulleys transmission profile as a mathematical solution that is then implemented to achieve contact force isotropy on the phalanges. A VSA is proposed, in which three VSAs are designed to act as a muscle in joint space to provide firm grasping. As a mechatronic approach, a suitable type and number of force sensors and actuators are designed to sense the touch, actuate the finger, and tune the VSAs. The torque of the VSAs is controlled utilizing a designed Multi Input Multi Output (MIMO) fuzzy controller. The fuzzy controller input is the force sensors' signals that are used to set the appropriate VSA torque. The fuzzy controller parameters are then tuned using a genetic algorithm as an optimization technique. The objective function of the genetic algorithm is to avoid unbalance torque in the individual joints and to reduce the difference between the values of the supplied VSAs torques. Finally, the operation of the aforementioned finger system is organized through a simple control algorithm. The function of this algorithm is to enable the detection of the unknown object and simultaneously automatically activate the optimized fuzzy controller thus eliminating the necessity of any external control unit.

Energy and Rate-Aware Design for HEVC Motion Estimation Based on Pareto Efficiency

This paper presents a high-throughput energy and rate-aware hardware design for the Motion Estimation (ME) according to the High Efficiency Video Coding (HEVC) standard. The hardware design implements a modified Test Zone Search (TZS) algorithm to perform Integer Motion Estimation (IME) as well as the Fractional Motion Estimation (FME) defined by the HEVC standard. Based on evaluations with the HEVC Reference Software, a complexity-reduction strategy was adopted in the developed architecture that mainly consists of supporting only the 8x8, 16x16, 32x32, and 64x64 Prediction Unit (PU) sizes rather than using the 24 possible PU sizes. The architecture allows an external control unit selects a subset of these four PU sizes according to the energy and rate targets for a specific application. The possible operation points were determined based on Pareto Efficiency. The architecture was described in VHDL, and the synthesis results for ASIC 45nm Nangate standard cells show that the developed architecture can process at least 53 frames per second (fps) considering Ultra-High Definition (UHD) 4320p videos. When an average-case of processing is considered, the architecture is able to process 112fps at UHD 4320p resolution.