Parallel Feedback Research Articles

Intelligent Covert Satellite Communication for Military Robot Swarm

Military robot swarm becomes more and more important for contemporary military application. In order to satisfy sophisticated application scenarios, novel communication architecture for military robot swarm has to be conceived. In this paper, we propose a multi-carrier intelligent covert satellite communication (MCICSC) architecture based on electromagnetic environment sensing technology, in where the ability of dynamically adapting the system configuration to the holistic requirements of covertness, performance, and complexity can be considerably improved. Additionally, in order to solve the carrier synchronization problem in very low signal noise ratio (SNR) for each data stream of MCICSC, polar code (PC) is incorporated into the proposed MCICSC system. With the aid of the proposed polar code-aided multi-stream parallel feedback (PAMSPF) carrier synchronization scheme, the MCICSC system is capable of realizing high-precise carrier synchronization even in very low SNR region. Moreover, in order to further decrease the complexity of our MCICSC system, we also propose a polar code-based diversity combining (PBDC) scheme, which is capable of efficiently combing all the data streams without the aid of channel state information (CSI) estimation. Numerical simulations demonstrate that for MCICSC system the performance of the PAMSPF carrier synchronization and PBDC combining schemes can get extremely close to that of an ideally synchronized system. Complexity analysis of the proposed algorithms is given as well.

Languages of Violence

Languages of Violence is a gaming/sound performance mediated by the streaming service Twitch. The visual elements represent the active key registrations and inputs being made during a video game, while the sound is of the game as it’s played and mixed through analog pedals and feedback loops. The context of the game and the event that it produces are obscured by this interpretation. What’s left is an impressionistic gesture that mediates a fact of violence. At the outset of this work, I was exploring what I saw left open by realistic digital violence, in that it can be directed beyond its actual origins. Gunfire is made indistinguishable from a real life event, but its context as a video game rescues it or makes it acceptable.

A Highly Linear Neuromorphic Synaptic Device Based on Regulated Charge Trap/Detrap

In this letter, we present highly linear potentiation/depression behaviors of a neuromorphic synaptic device made of CMOS-compatible floating gate (FG) cells. The kinetics of the charge trap/detrap mechanism under various pulse shapes are analyzed to design a simple 2C-4T FG cell with a modulated column write driver for embedded incremental step pulse programming (ISPP) via analog feedback. Utilizing real-time ISPP, the linearity and symmetry of the weight update were significantly improved due to the content-aware programming strength. Moreover, the proposed circuit technique provides flexibility regarding the size of the program/erase steps in addition to the superior linearity. The proposed FG cells with peripheral circuits are fabricated using 180nm CMOS technology and exhibited a differential non-linearity (DNL) less than 0.946 least significant bit (LSB) with 100 weight states. The excellent linearity remains unchanged even when the directions of potentiation /depression are reversed throughout the entire range.

Controlled Position Navigation of Single Degree Magnetic Levitation

A permanent magnet is levitated following the electromagnetic suspension principle using the attractive magnetic force of a wire-wound electromagnet with a hall-effect sensor for position feedback. Taking the hall-effect voltage as an analog parameter and feedback signal to the micro-controller, the strength of the electromagnet is controlled by adjusting the current using the Pulse Width Modulation technique in order to levitate the permanent magnet. The stability of the levitated magnet is enhanced by the use of PID algorithm in the embedded system. Use of Laplace transform for simplification of differential equations and Taylor series for the linearization of system function supports the mathematical computation required for the levitation. Furthermore, by making the feedback signal from hall-effect sensor dependent only on the magnetic field of levitating magnet, an advancement in levitation phenomenon is achieved that aids the levitation with a greater flexibility of changing the position of the levitating magnet along the gravitational axis within a specified range.So the paper depicts about the Controlled Position Navigation of Single Degree Magnetic Levitation.

A Novel Fully Analog Signal Conditioning Circuit for Loss-Less Capacitive Sensor Estimation

In this paper, a novel fully analog signal conditioning circuit for loss-less capacitive sensor estimation has been introduced. The proposed circuit employs a new form of the Wheatstone bridge in order to implement a novel null instrument. In contrast to the conventional ac Wheatstone bridge, all components of the used bridge, except capacitive sensor, are conventional resistors. Therefore, the used bridge is intrinsically unbalanced. In order to balance the bridge, a fully analog feedback network has been used. The main advantage of the proposed circuit over previous null instruments is that, it no longer requires controllable elements such as voltage controlled resistor in order to implement the feedback loop. In the proposed circuit, the bridge is balanced by using a simple and appropriate feedback network which is made by using only an operational amplifier and a resistor. The proposed circuit has been realized only by the use of Op-Amp-based amplifiers and a differential amplifier. Due to the simplicity of the architecture, it can be made by discrete and inexpensive parts. The suggested signal conditioning circuit is excited by a Sine voltage source and the phase difference between output and input voltages depends on the capacitive sensor value. The capacitive sensor estimation can be done by measuring the foresaid phase difference.

A synergetic strategy of automobile intelligent cruise system based on fuzzy control adopting hierarchical structure

To improve automobile travel safety and relieve the intension of driving fatigue, a synergetic strategy on the throttle and brake combined control of automobile cruise system is proposed based on fuzzy control theory. A hierarchical control structure, including the upper fuzzy controller and the lower model match controller, is designed for integrated control function. The upper controller consists of the two input variables, that is, the deviation of the theoretical safe distance and the relative distance and the relative velocity between the host car and the preceding vehicle, and the single output variable, that is, the excepted acceleration of host car. The lower controller has achieved the fast compensation of excepted acceleration by adopting parallel feedforward and feedback compensator to input into the inverse dynamics model of automobile cruise system. Using MATLAB/Simulink, the control function on the proposed synergetic strategy is validated for different working cases. The results show that the synergetic strategy possesses an integrated capability involved automated stop & go control, and following the preceding car to prevent rear-end collision, and the constant velocity cruise whether the driving conditions of the city road or expressway.

Accurate and Fast On-Wafer Test Circuitry for Device Array Characterization in Wafer Acceptance Test

This paper proposes an on-wafer test circuitry for rapidly and accurately characterizing the devices under tests (DUTs) of the DUT array in the wafer acceptance test (WAT) to qualify wafers faster and more reliably. The proposed test cell simply comprises a DUT and a selection MOSFET operating in the saturation region as a current buffer when being activated. An analog feedback loop with a replica-biasing circuit tracks the selected DUT’s output current and automatically biases the selection MOSFET’s gate so as to accurately duplicate the desired setup voltage at the selected DUT’s output node. Comparing with conventional designs using the Kelvin sensing scheme to address the switches’ IR drops, the proposed design has less transistor counts, shorter test time, and no risk of forward-bias p-n junctions. Consequently, it achieves a lower test cost and a higher test throughput. The whole proposed test circuitry including 1024 NMOS DUTs has been designed and fabricated in 90-nm CMOS. The active area is only $60~\mu \text{m}$ by $800~\mu \text{m}$ which is small enough to be placed into the scribe line on wafers as conventional WAT circuitry is. Measurement results demonstrate the proposed design’s efficiency and capability of revealing local process variations.

Compact and Low-Phase-Noise Oscillator Employing Multilayer Sixteenth-Mode Substrate-Integrated Waveguide Filter for 5G Applications

In this paper, a compact and low-phase-noise (PN) free-running oscillator designed by sixteenth-mode substrate-integrated waveguide (SMSIW) bandpass filter (BPF) for 5G applications is proposed. The size of SMSIW cavity exhibits only one-sixteenth of the conventional SIW cavity. The SMSIW BPF is designed by using multilayered printed circuit board (PCB) process, and the active circuits and power divider are positioned on the top layer and bottom layer, respectively. The vertical feedback is achieved by using feedlines of SMSIW BPF and metallic via-hole. A parallel feedback configuration oscillator with four-order cross-coupling SMSIW BPF has been designed, fabricated, and measured. The measured results show that at the oscillation frequency of 3.52 GHz with −1.5-dBm output power, the PN is −107.36 and −132.07 dBc/Hz at 100 kHz and 1 MHz frequency offset, respectively. The figure of merit (FOM) at 1-MHz frequency offset is −191 dBc/Hz. Moreover, the size of SMSIW BPF is only $0.267\lambda _{\mathbf {0}}\times 0.109\lambda _{\mathbf {0}}$ . The proposed oscillator effectively demonstrates the advantages of compact size and low PN.

Investigation and Modeling of Combined Feedforward and Feedback Control Schemes to Improve the Performance of Differential Mode Active EMI Filters in AC–DC Power Converters

In this paper, the models of active differential mode electromagnetic interference input filters for ac–dc converters are first investigated. The models are developed for active filters with single feedback (FB) and single feedforward (FF) configurations, which include an active filter, passive filters, and the noise model for a converter. To increase the gain of the single active filter, the models for FB–FF, FF–FB, parallel FB, and series feedback (SFB) configurations are developed and investigated. Loop gains and insertion gains for all of these configurations are derived and compared. Stability has been analyzed based on the loop gains and a compensation technique is introduced to ensure stability. Based on the comparison among all these control configurations, it has been found that the SFB configuration can achieve the highest noise reduction. The loop gains and insertion gains of an active filter prototype with the SFB configuration are measured using a network analyzer to validate the developed model and compensation technique. Finally, spectrum measurements with a commercial boost power factor correction ac–dc converter have been conducted to verify the developed modeling and control techniques as well as the predicted performance for the SFB configuration.

A compact laser system for a portable atom interferometry gravimeter.

A compact laser system for a portable 87Rb atom interferometry gravimeter has been demonstrated in this work. This laser system is based on frequency doubling of a single seed laser at the wavelength of 1560 nm. The frequency of the seed laser is controlled by a digital unit with an analog feedback circuit. By using this frequency control method, the frequency of the laser system can be shifted over 1 GHz. Based on this method, the Raman frequency can be locked on the F = 3 → F' = 4 transition of 85Rb atoms. Moreover, the Raman sideband and the repumping laser are generated by a phase modulator, and it can generate different laser frequencies to meet the requirements of a typical atom interferometer. Additional sidebands in the Raman beam produced from the phase modulator are optimized and reduced, allowing us to observe atom interference with a free evolution time of 320 ms. The control unit including the laser system has been integrated into a box with a volume of 1.5 m × 0.6 m × 0.6 m, and the weight of which is only 150 kg. Using this compact optical scheme, our atomic gravimeter has achieved a sensitivity of 53 μGal/Hz1/2 and a resolution of better than 1 μGal (1 μGal = 1 × 10-8 m/s2) in an integration time of 3000 s.

An Artificial Tissue Homeostasis Circuit Designed via Analog Circuit Techniques.

Tissue homeostasis (feedback control) is an important mechanism that regulates the population of different cell types within a tissue. In type-1 diabetes, auto-immune attack and consequent death of pancreatic β cells result in the failure of homeostasis and loss of organ function. Synthetically engineered adult stem cells with homeostatic control based on digital logic have been proposed as a solution for regenerating β cells. Such previously proposed homeostatic control circuits have thus far been unable to reliably control both stem-cell proliferation and stem-cell differentiation. Using analog circuits and feedback systems analysis, we have designed an in silico circuit that performs homeostatic control by utilizing a novel scheme with both symmetric and asymmetric division of stem cells. The use of a variety of feedback systems analysis techniques, which is common in analog circuit design, including root-locus techniques, Bode plots of feedback-loop frequency response, compensation techniques for improving stability, and robustness analysis help us choose design parameters to meet desirable specifications. For example, we show that lead compensation in analog circuits instantiated as an incoherent feed-forward loop in the biological circuit improves stability, whereas simultaneously reducing steady-state tracking error. Our symmetric and asymmetric division scheme also improves phase margin in the feedback loop, and thus improves robustness. This paper could be useful in porting an analog-circuit design framework to synthetic biological applications of the future.

Evidence for non-steady-state carbon emissions from snow-scoured alpine tundra

High-latitude warming is capable of accelerating permafrost degradation and the decomposition of previously frozen carbon. The existence of an analogous high-altitude feedback, however, has yet to be directly evaluated. We address this knowledge gap by coupling a radiocarbon-based model to 7 years (2008–2014) of continuous eddy covariance data from a snow-scoured alpine tundra meadow in Colorado, USA, where solifluction lobes are associated with discontinuous permafrost. On average, the ecosystem was a net annual source of 232 ± 54 g C m−2 (mean ± 1 standard deviation) to the atmosphere, and respiration of relatively radiocarbon-depleted (i.e., older) substrate contributes to carbon emissions during the winter. Given that alpine soils with permafrost occupy 3.6 × 106 km2 land area and are estimated to contain 66.3 Pg of soil organic carbon (4.5% of the global pool), this scenario has global implications for the mountain carbon balance and corresponding resource allocation to lower elevations.

Frequency domain properties and fundamental limits of buffer–feedback regulation in biochemical systems

Feedback regulation in biochemical systems is fundamental to homeostasis with failure causing disease or death. Recent work has found that cooperation and synergy between feedback and buffering – the use of reservoirs of molecules to maintain molecular concentrations – are often critical for biochemical regulation, and that buffering can act as a derivative or lead controller. However, buffering differs from derivative feedback in important ways: it is not typically limited by stability constraints on the parallel feedback loop, for some signals it acts instead as a low-pass filter, and it can change the location of disturbances in the closed-loop system. Here, we propose a frequency-domain framework for studying the regulatory properties of buffer–feedback systems. We determine standard single-output closed-loop transfer functions and discuss loop-shaping properties. We also derive novel fundamental limits for buffer–feedback regulation, which show that buffering and removal processes can reduce the fundamental limits on feedback regulation. We apply the framework to study the regulation for glycolysis (anaerobic metabolism) with creatine phosphate buffering.

A Pulse Frequency Modulation VCO-ADC in 40 nm

This brief describes the architecture and implementation of a novel voltage-controlled oscillator-based analog-to-digital converter (VCO-ADC). Instead of a ring oscillator, the VCO is built with a pulse frequency modulation architecture where an analog feedback loop ensures both oscillation and linearity of the voltage-to-frequency conversion. A multibit first-order noise-shaped output is achieved by sampling a digital delay line that acts as a part of the oscillator and as a multibit quantizer. A prototype has been implemented in a 40-nm CMOS process. Although most of the circuit elements are taken from a standard digital library, a transconductor is required as the input stage. To ensure proper linearity, a bulk-driven transconductor has been designed. The ADC measurements reach 53 dB of SNDR at 1 GHz sampling frequency in a 20-MHz bandwidth with a pseudo-differential architecture. Powered at 1.1 V, the power consumption is 3.5 mW. The active area is 0.08 mm2. The resulting figure-of-merit equals 242 fJ/step.

Q-learning trajectory planning based on Takagi–Sugeno fuzzy parallel distributed compensation structure of humanoid manipulator

NAO is the first robot created by SoftBank Robotics. Famous around the world, NAO is a tremendous programming tool and he has especially become a standard in education and research. Aiming at the large error and poor stability of the humanoid robot NAO manipulator during trajectory tracking, a novel framework based on fuzzy controller reinforcement learning trajectory planning strategy is proposed. Firstly, the Takagi–Sugeno fuzzy model based on the dynamic equation of the NAO right arm is established. Secondly, the design and the gain solution of the state feedback controller based on the parallel feedback compensation strategy are studied. Finally, the ideal trajectory of the motion is planned by reinforcement learning algorithm so that the end of the manipulator can track the desired trajectory and realize the valid obstacle avoidance. Simulation and experiment shows that the end of the manipulator based on this scheme has good controllability and stability and can meet the accuracy requirements of trajectory tracking accuracy, which verifies the effectiveness of the proposed framework.

An X‐band push‐push oscillator with parallel feedback configuration designed by microstrip balanced bandpass filter

In this article, a push-push oscillator with parallel feedback configuration designed by the microstrip balanced bandpass filter (BPF) is proposed. The push-push oscillator consists of two sub-oscillators with a balanced BPF. The balanced BPF with the open-circuited stubs exhibits the desired differential-mode frequency response and achieves high common-mode suppression simultaneously. Based on the technique of the balanced BPF, the out-of-phase fundamental signals and odd harmonic signals are canceled out while the even harmonic signals are well combined. The prototype of the push-push oscillator is designed and fabricated. Measured results show that the proposed push-push oscillator works at 9.96 GHz of the second harmonic frequency. The actual output power is −8.57 dBm. The rejection of the fundamental signal and third harmonic signal are better than 27 and 42 dBc, respectively. The phase noise of the proposed push-push oscillator is −128.3 dBc/Hz at 1 MHz frequency offset.

Multiuser Detection with Decision-Feedback Detectors and PIC in MC-CDMA System

In this paper we propose an iterative parallel decision feedback (P-DF) receivers associated with parallel interference cancellation (PIC) for multicarrier code division multiple access (MC-CDMA) systems in a Rayleigh fading channel (cost 207). First the most widely detection techniques, minimum mean-squared error MMSE, Maximum Likelihood ML and PIC were investigated in order to compare their performances in terms of Bit Error Rate (BER) with parallel feedback detection P-DFD. A MMSE DF detector that employs parallel decision-feedback (MMSE-P-DFD) is considered and shows almost the same BER performance with MMSE and ML, which present a better result than the other techniques. In a second time, an iterative proposed method based on the multi-stage techniques P-DFD (parallel DFD with two stages) and PIC was exploited to improve the performance of the system.

A high linearity low-noise amplifier in 0.25 μm BiCMOS Qubic4x for GSM application

ABSTRACTIn this paper, a low-noise amplifier (LNA) in 0.25 μm BiCMOS Qubic4x technology for Global System for Mobile communications (GSM) application is presented. The LNA uses inductive source degeneration to achieve noise and power gain matching simultaneously and parallel RC feedback to improve linearity. The LNA provides a forward gain (S21) of 10.3 dB with noise figure (NF) of 1.5 dB while drawing 50.6 mW power from a 1.6 V voltage supply. The simulated 1-dB compression point is 0 dBm at 942 MHz. The simulations are done in cadence virtuoso Spectre RF using 0.25 μm BiCMOS Qubic4x technology.

Retracted: A simple algorithm for reducing the operation frequency of residential water pumps during peak hours of power consumption

AbstractIn developing countries where water supply pressure is low, or frequent water outages and electricity shortages happen, domestic end‐users are forced to install water pump‐storage systems, consisting of water pumps and ground‐level and rooftop tanks to satisfy their daily water demands. This contributes to increasing electrical energy consumption, particularly during peak electricity demand hours. This study presents a simple, practical, computational, and cost‐effective shifting water level control algorithm to manage water‐energy nexus, by reducing pump‐storage system electric energy consumption during peak hours. The proposed algorithm requires a simple modification to the existing water level control scheme, by installing an additional float switch in the rooftop water tank below the currently available float switch that is usually adjusted to trigger the pump when the level in the tank drops by 5‐10% from the maximum level. Based on the simulation results, the algorithm preserves the domestic end‐users’ comfortable daily water demand and reduces water pump energy consumption during peak hours by 90%. During off‐peak hours, the control algorithm triggers the pump to refill the rooftop tank based on the upper float switch when water level drops by 5%, while during peak hours, the pump is triggered only when the water drops by 30%. The performance of the algorithm is found to be comparable to the performance of the model predictive control (MPC) approach developed for the same purpose, but MPC needs a high computation capacity and a complex analog feedback level sensor. The algorithm succeeds in reducing and shifting pump energy consumption under various possible operation scenarios and water demand disturbances. A mathematical model is developed for the domestic water pump‐storage system using Matlab/Simscape to cope with the complexity of solving nonlinear fluid flow equations and measure the data required to develop the control algorithm. The performance of the algorithm is tested based on a real case study.

Linear positioner based on pneumatic muscle

The main goal of the work is to investigate the technical possibilities of creating a linear positioner on the basis of pneumatic muscle with acceptable characteristics for positioning. The experimental study of the power characteristics of the pneumatic muscle of the MAS 10-300 series of “FESTO” company is carried out. The physical essence of the cylindrical membrane operation is considered, on the basis of which the pneumatic muscle is constructed and a method for calculating the parameters of the positioning spring has been developed. It is shown that if the positional component is present in the load of pneumatic muscle then its rigidity (the dependence of the force on displacement) allows solving the task of positioning by controlling the pressure in the internal cavity of pneumatic muscle. If there is no positional component in the load or it is too small, then a positioning spring is needed to solve the positioning problem. Methods for determining the parameters of the positioning spring for positioners created on the basis of MAS pneumatic muscles of “FESTO” company are given. It has been established that the pneumatic muscle, which is used as a linear pneumatic motor, generates a pulling force which, with zero reduction of the pneumatic muscle, is 12 ... 14 times greater than the force developed on the return stroke by a pneumatic cylinder of equal working area of the piston and the specific force (force referred to the mass of the pneumatic motor) of pneumatic muscle is 100 times larger. This makes it possible to use pneumatic muscle as a loading device for brake, clamping and tensioning devices of transport systems and mobile units. To use the positioner in the tracking position control system, it must be provided with an analog feedback sensor. The static characteristic of the created physical layout of the positioner, obtained experimentally, has a quasilinear section in the range of the control pressure change of 2.5 ... 5 bar and agrees well with the calculation results. The nature of the transient process with respect to the input effect makes it possible to treat the positioner as an aperiodic link of the first order with a time constant T = 2 ... 5 s. As an example, the possibility of using a positioner in solving problems related to the need to stabilize a cargo platform in a horizontal position, in the case of a shift of the center of gravity of the cargo relative to the vertical axis of the platform, was investigated. The results of the work can be used and implemented in solving problems of linear and angular positioning of the load in flexible production systems, in executive devices of industrial robots, etc.