Multimode Parallel Research Articles

Type Synthesis of a Novel Class of 1-DOF Multi-Mode Parallel Mechanisms

Type Synthesis of a Novel Class of 1-DOF Multi-Mode Parallel Mechanisms

Working mode division and shift schedule extraction of a parallel hybrid power system

Abstract For hybrid electric vehicles, working mode division and shift schedule are two decisive factors affecting vehicle fuel economy. This paper introduces a method for vehicle working mode division and shift schedule determination on the basis of optimal system efficiency. The key index named ‘fuel-electricity conversion efficiency’ is defined and calculated. Via this method, unreasonable gear modes in specific working modes are excluded and the mode transition map and upshifting curves in each working mode are extracted. The simulation results demonstrate that, with the application of the single-motor multi-mode parallel hybrid power system, the proposed mode transition and shifting strategy can increase vehicle fuel economy by 12.99%.

Cross-connection of multiplexed cylindrical vector beams using off-axis spin-decoupled metasurfaces.

Cylindrical vector beam (CVB) multiplexing communication demands effective mode cross-connection techniques to establish communication networks. While methods like polarized grating and coordinate transformation have been developed for (de)multiplexing CVB modes, challenges persist in the cross-connection of these multiplexed mode channels, including multi-mode conversion and inhomogeneous polarization control. Herein, we present an independent off-axis spin-orbit interaction strategy utilizing spin-decoupled metasurfaces. Cross-connection is achieved by encoding conjugated Dammann optical vortex grating phases onto the two orthogonal circularly polarized components of CVBs. Experimental results demonstrate the successful interconversion of four CVB modes (CVB+1 and CVB-2, CVB+2 and CVB-4) using a Si-based metasurface with a polarization conversion efficiency exceeding 85%. This facilitates the cross-connection of 200 Gbit/s quadrature phase-shift keying signals with bit-error-rates below 10-6. Offering advantages such as ultra-compact device size, flexible control of CVB modes, and multi-mode parallel processing, this approach shows promise in advancing the networking capabilities of CVB mode multiplexing communication networks.

Research on economical shifting strategy for multi-gear and multi-mode parallel plug-in HEV based on DIRECT algorithm

In response to the discrepancy between the mechanical-electric torque distribution rules used in the shifting calculation of plug-in hybrid electric vehicles and the actual operating conditions, this study focuses on a specific vehicle model known as the multi-gear and multi-mode parallel plug-in hybrid electric vehicle (MGMMP-PHEV). Various control parameters including vehicle speed, pedal opening, battery state of charge (SOC), and operating mode are taken into account by considering the impact of coordinated operation between the dual power sources and battery SOC. In order to address this issue, an enhanced dual-parameter shifting calculation principle and method are proposed, and an optimized shifting strategy is developed with the objective of achieving the highest system comprehensive efficiency and ensuring battery charge-discharge balance. The shifting points under each mode are optimized offline using the DIviding RECTangles (DIRECT) algorithm, and a multi-parameter fuzzy controller is introduced to dynamically adjust the shifting speed. The improved shifting strategy, implemented in Matlab/Simulink, is compared with the initial shifting strategy in terms of its economic performance. The results demonstrate that the DIRECT-optimized and dynamically adjusted fuzzy shifting strategy effectively maintains the balance of battery charge and discharge. Specifically, under the WLTC working condition, it achieves a 5.59 % reduction in fuel consumption compared to the dual-parameter shifting strategy. Furthermore, this optimized strategy leads to a slight increase in shifting delay and a decrease in shifting frequency, thus verifying the effectiveness and superiority of the proposed controller.

Kinematics, Workspace, and Singularity Analysis of a Parallel Robot With Five Operation Modes

Most multimode parallel robots can change operation modes by passing through constraint singularities. This paper deals with a comprehensive kinematic study of a three degrees-of-freedom (DOF) multimode three-PRPiR parallel robot developed at Heriot-watt University. This robot is able to reach several operation modes without crossing any constraint singularity by using lockable Pi and R joints. Here, a Pi joint may act as a 1DOF planar parallelogram if its lockable P (prismatic) joint is locked or a 2DOF RR serial chain if its lockable P joint is released. The operation modes of the robot include a 3T operation mode and four 2T1R operation modes with two different directions of the rotation axis of the moving platform. The inverse kinematics and forward kinematics of the robot in each operation mode are dealt with in detail. The joint space and workspace analysis of the robot allow us to know the regions of the workspace that the robot can reach in each operation mode. It is shown that the robot is able to change assembly mode in one operation mode by passing through another operation mode.

Comparison of multi-mode parallel detection microscopy methods

Four microscopy resolution enhancement methods based on parallel detection were investigated in this study: confocal microscopy with four pinhole sizes, fluorescence emission difference microscopy (FED) based on parallel detection, Airyscan microscopy, and virtual k-vector modulation optical microscopy (Vikmom). These methods use different algorithms to process parallel detection data and achieve resolution improvement. We investigated these methods first by performing simulations and then experimentally. In this report, the basic theories of these methods are briefly introduced. Then, analyses and comparisons of their imaging performances, especially in terms of resolution improvement, imaging speed, and signal-to-noise ratio, are presented. Finally, the results of our comparative study are summarized.

Feasibility Assessment and Design Optimization of a Clutchless Multimode Parallel Hybrid Electric Powertrain

The fuel economy (FE) of the parallel hybrid electric vehicle (HEV) suffers due to significant energy losses from the wet clutches of the automatic transmission and limited engine operations. To overcome these limitations, a novel clutchless multimode parallel HEV (CMP-HEV) was proposed previously, but its operational feasibility was not proven. In this study, we propose a systematic methodology that can assess the feasibility of the CMP-HEV and efficiently optimize FE and acceleration performance of the design, simultaneously. Using the dynamic models, we assess the feasibility over the entire design spaces under two conditions: full acceleration (for drivability) and moderate acceleration (for fuel efficiency). An instantaneous optimization method is used to rapidly evaluate the full acceleration performance, and the designs with poor acceleration are considered infeasible. For the fuel efficiency, the feasibility is determined by the violation of electric motor constraints under the assumption of efficient engine operations. The feasible design sets from the assessment are used for the design optimization. Dynamic programming is applied over only the feasible design space, and the Pareto front is obtained to show the tradeoff between FE and acceleration performance. The selected final design is found superior to a comparable parallel HEV in both FE and acceleration performance perspectives.

Multi-mode parallel and folded VLSI architectures for 1D-fast Fourier transform

The modern real time applications like orthogonal frequency division multiplexing and etc., demand high performance fast Fourier transform (FFT) design with less area and clock cycles. This paper proposes efficient FFT VLSI architectures using folded/parallel implementation. In the proposed folded FFT architecture, the number of cycles required to complete the operation is less than single path delay feedback (SDF)/multi-path delay commutator (MDC) architectures. In the proposed parallel FFT architecture, N-point FFT is implemented by using one N/2-point FFT without much extra hardware. Both the proposed architectures are implemented for radix-2, 22, and 4 using 45nm technology library. The proposed parallel architecture achieves 56.7% and 40.6% of area reduction as compared with the existing parallel architecture based 16-point radix-2 and radix-22 DIF FFTs respectively. The proposed folded architecture achieves 65.5%, 51.1%, and 35.8% of worst path delay reduction as compared with the existing SDF based 16-point radix-2, radix-22, and radix-4 DIF FFTs respectively.

Fuel economy assessment of novel multi-mode parallel hybrid electric vehicle

In this paper, a multi-mode parallel hybrid power-train so called clutchless geared smart transmission (CGST), is proposed and assessed in terms of the fuel economy. The use of a single motor/generator and a planetary gear enables the CGST to provide remarkable flexibility with four operational modes including the parallel hybrid mode. Based on its novel configuration, a fuel consumption model is newly developed and simulated to analyze the fuel economy of the CGST. The performance of the CGST is compared with those of the power-split hybrid system and the conventional manual transmission in city and highway cycles. The CGST shows the best efficiency in highway driving by reducing the unnecessary energy loss from the electric motor. Moreover, thanks to brake-regeneration and efficient engine operation with the specific operational modes, the fuel economy in the city cycle is comparable to that of the power-split hybrid system even though the CGST uses just a single electric motor.

Analysis of interchannel crosstalk in multimode parallel optical waveguides using the beam propagation method.

We theoretically analyze the origin of inter-channel crosstalk in densely aligned multimode parallel optical waveguides for on-board interconnects using the Beam Propagation Method. In this paper, we demonstrate that the inter-channel crosstalk due to mode coupling is very low in graded-index (GI) circular-core waveguides because the propagation constants of the propagating modes are discrete. Additionally, it is also found that the waveguides with GI-type circular cores is sensitive to the optical confinement in the cladding: low-power cladding modes largely decrease the mode conversion.

Type Synthesis of 3-DOF Parallel Manipulators With Both a Planar Operation Mode and a Spatial Translational Operation Mode1

Type synthesis of multimode parallel manipulators (PMs) (also parallel manipulators with multiple operation modes) is an open issue in the research on reconfigurable mechanisms and robots. This paper deals with the type synthesis of 3-DOF (degree-of-freedom) parallel manipulators with both a planar operation mode and a spatial translational operation mode. The type synthesis of planar parallel manipulators, which refer to parallel manipulators in which the moving platform undergoes planar motion, is first dealt with using the virtual-chain approach. Types of planar parallel manipulators, including those involving Bennett compositional unit (CU), are obtained. Then, the types of 3-DOF parallel manipulators with both a planar operation mode and a translational operation mode are obtained. This paper focuses on 3-DOF parallel manipulators composed of only revolute joints. This work contributes to the type synthesis of parallel manipulators and can be extended to the type synthesis of other classes of multimode parallel manipulators.

Palladium(0)-Catalyzed, Copper(I)-Mediated Coupling of Cyclic Thioamides with Alkenylboronic Acids, Organostannanes, and Siloxanes

The Pd-catalyzed cross-coupling of cyclic thioamides and thioureas with alkenylboronic acids, vinyl- and (het)arylstannanes, and arylsiloxanes in the presence of stoichiometric amounts of a Cu(I) cofactor is described. The desulfitative C-C cross-coupling protocol of the Liebeskind-Srogl type is performed under neutral conditions and can be applied to a range of heterocyclic structures with embedded thioamide fragments. Employing controlled microwave irradiation at 100 degrees C utilizing either a single-mode reactor or a multimode parallel reaction platform, cross-couplings can generally be completed within 1-3 h and proceed in good yields.

Performance simulation and predictive model for a multi-mode parallel hybrid electric scooter drive

This paper presents a parallel hybrid electric scooter model developed on MATLAB-Simulink. The hybrid electric scooter model was developed to further understand and analyze as well as to predict its performance before proper construction of the prototype begins. The model consists of four main models that formed the complete hybrid scooter model: battery model, engine model, DC motor model and the dynamics model. The multi-mode controller predicts the required parameters to operate the scooter in an optimize condition. Experimental data were gathered and thus compared to the simulated data to check the model's feasibility and accuracy on four distinct driving cycles: modified urban dynamometer driving schedule (UDDS), New York city cycle (NYCC), European driving cycle (ECE-15) and modified highway fuel economy driving schedule (HWFET). Basic studies showed that the model developed had a maximum of 4% error. Maximum error achieved between the theoretical and the experimental readings is about 3.15%, which is for the modified HWFET cycle. Other cycles have acceptable errors; UDDS cycle with 1.91%, NYCC cycle with a low 0.68% and ECE-15 cycle with 1.15%. Operating costs between the internal combustion engine mode, motor mode and hybrid mode were also estimated, where final results showed an 18% reduction of the overall fuel consumption using the multi-mode controller between hybrid scooters and conventional scooters. The fuel consumptions were also predicted and compared the estimated results with one commercially available hybrid scooter, Piaggio Vespa MP3 hybrid scooter. Primary results showed a 4.4% increase in distance travelled per kilometer. Copyright © 2009 John Wiley & Sons, Ltd.

Reversible quantum optical data storage based on resonant Raman optical field excited spin coherence

A method of reversible quantum optical data storage is presented using resonant Raman field excited spin coherence, where the spin coherence is stored in an inhomogeneously broadened spin ensemble. Unlike the photon echo method, in the present technique, a 2pi Raman optical rephasing pulse area is used and multimode (parallel) optical channels are available in which the multimode access gives a great benefit to quantum information processors such as quantum repeaters.

Waveguide bandpass filter analysis and design using multimode parallel FDTD diakoptics

This paper presents an analysis and design method based on finite-difference time-domain diakoptics. A complex structure is divided into several smaller subsections. The characteristics of the subsections are analyzed entirely in the time domain using mode-type discrete time-domain Green's functions. A multimode parallel algorithm is proposed to connect the subsections. Several filter analysis and design examples are presented. The effectiveness and accuracy of this method is demonstrated by comparison with other computational methods and measurements.