Dynamic Compensation Research Articles

YOLODCC: Improved YOLOv8 combined with dynamic confidence compensation for lightweight moving object detection

AbstractMost multiple object tracking algorithms depend on the output of the detector. Aiming at the problem that the higher detection quality model is restricted by the computing power, and the robustness of the lightweight detection model is easily affected by motion blur, this paper proposes a lightweight moving object detector based on improved YOLOv8 combined with dynamic confidence compensation algorithm. The algorithm combines various technical means such as network structure optimization, lightweight design, self‐knowledge distillation, loss function improvement and dynamic confidence compensation. ByteTrack is used as a tracker to conduct experiments on PASCAL VOC07+12 data set and UA‐DETRAC test sequence. Compared with the baseline YOLOv8n+ByteTrack, the proposed algorithm improves the HOTA by 1.3% when the single frame tracking delay is reduced by 1.1%. Mostly tracked target is improved by 79.7%, mostly lost target is reduced by 10.9%, and the detection effect is better than the original detector and other popular object detectors. The YOLODCC model achieves a balance between lightweight and multi‐object motion blur.

Criteria for selection of point-ahead angle compensation strategy in intersatellite laser ranging interferometry of TianQin based on research of tilt-to-length coupling noise

TianQin is expected to deploy three spacecraft in Earth orbit at the altitude of about 1 × 108 m to form an equilateral triangular constellation with arm lengths of about 1.7 × 108 m. It is aimed at detecting gravitational waves in the frequency range from 0.1 mHz to 1 Hz by means of high sensitive laser ranging interferometry with pathlength measurement noise below 1 pm/Hz1/2. The long-range propagation of beam in the intersatellite laser ranging interferometry between the three spacecraft results in a non-negligible time delay of 0.58 s. Therefore, there is an angular difference between the optimal outgoing and incoming laser beam of laser ranging interferometry on each spacecraft, which is denoted as the point-ahead angle. Due to the relative motion between the three spacecraft, the point-ahead angle of TianQin constellation is approximately 22.96 μrad with a dynamic variation range of ±24.71 nrad. Point-ahead-angle mechanism is a fine steering mirror used for point-ahead angle compensation to diminish the beam pointing error, thus to maintain the intersatellite laser link as well as to diminish the tilt-to-length coupling noise, which are vital to the gravitational wave detection. Both the static and dynamic point-ahead angle compensation strategies can be used in TianQin and the selection of the two is based on minimizing the total point-ahead-angle-related tilt-to-length coupling noise. In this paper, a criteria for selection of the two strategies are proposed by establishing a model of point-ahead-angle-related tilt-to-length coupling noise as well as a corresponding evaluation function for calculation and comparison. The results indicate that the dynamic compensation strategy is the optimal choice only when the first-order tilt-to-length coupling coefficient of point-ahead-angle mechanism is less than 6.4 × 10−9 m/rad, otherwise the static compensation strategy should be used. The proposed criteria, as well as the model and the requirement for point-ahead-angle mechanism, can serve as a common theoretical basis in laser ranging interferometry applications.

Fully distributed adaptive consensus tracking for uncertain multi-agent systems

This work discusses the adaptive consensus tracking for first-order and second-order uncertain multi-agent systems (UMASs). The systems allow multiple uncertainties, including unknown control directions, parameterized unknown nonlinearities, and unknown external disturbances. To compensate for these uncertainties, two novel distributed adaptive control protocols with the dynamic compensation based on Nussbaum-type gain are proposed for first-order and second-order UMASs, respectively. Remarkably, the control protocol is devised in a fully distributed fashion, which is not dependent on the global information of communication graph. Then, under undirected connected graph, it is proved that the proposed control protocol can guarantee the boundedness of all signals in the closed-loop system and the achievement of the consensus tracking (CT). Finally, the theoretical results are validated by two simulation examples.

Mesh Optimisation for General 3D Printed Objects with Cusp-Height Triangulation Approach

3D printing (3DP) is increasingly utilized to achieve quick turnaround on various geometric designs and prototypes, being the growing part of additive manufacturing technology (AMT). The 3DP technique effectively improves the production of complex models in terms of low-cost, time-consuming production, and with less material volume. The key to results optimisation with 3DP is the preparation of the geometry. The following techniques can effectively reduce the required time of the 3D printing process for complex and non-linear CAD files. The fused deposition modelling/fabrication (FDM/FFF) techniques become the first choice in many applications, including biomedical ones. Still, some obstacles exist in the geometry roughness and quality zones. This paper proposes an optimisation method for 3D printed shapes used in biomedical devices and instrumentation by minimising the support structure attached to the model using the FDM technique. In this research, we proposed a method for dynamic compensation against gravity-affected parts extended from the main object’s geometry using a forward planar learning (FPL) algorithm to minimise cusp height in 3D printed objects. After the slicing stage, the outcomes proved to be of good quality, optimised the object’s surfaces, and minimised the printing time by 32%–38%. The proposed method is promising in defining a better setting for slicing and toolpath for FDM 3D printing. However, this method was not tested on other 3DP methods (Stereolithography (SLA), Selective laser sintering (SLS), and Digital Light Processing (DLP)), as more verification efforts need to be done on these 3D printing processes.

Acceleration Slip Regulation Control Method for Distributed Electric Drive Vehicles under Icy and Snowy Road Conditions

To achieve a rapid and stable dynamic response of the drive anti-slip system for distributed electric vehicles on low-friction surfaces, this paper proposes an adaptive acceleration slip regulation control strategy based on wheel slip rate. An attachment coefficient fusion estimation algorithm based on an improved singular value decomposition unscented Kalman filter is designed. This algorithm combines Sage–Husa with the unscented Kalman filter for adaptive improvement, allowing for the quick and accurate determination of the road friction coefficient and, subsequently, the optimal slip rate. Additionally, a slip rate control strategy based on dynamic adaptive compensation sliding mode control is designed, which introduces a dynamic weight integral function into the control rate to adaptively adjust the integral effect based on errors, with its stability proven. To verify the performance of the road estimator and slip rate controller, a model is built with vehicle simulation software, and simulations are conducted. The results show that under icy and snowy road conditions, the designed estimator can reduce estimation errors and respond rapidly to sudden changes. Compared to traditional equivalent controllers, the designed controller can effectively reduce chattering, decrease overshoot, and shorten response time. Especially during road transitions, the designed controller demonstrates better dynamic performance and stability.

Autonomous ground vehicle gravity anomaly measurement and dynamic error compensation

Abstract To address the issue that dynamic gravity anomaly measurement is overly dependent on GNSS and can’t be measured autonomously at this stage, this paper proposes an autonomous ground vehicle dynamic gravity anomaly measurement method based on a strapdown inertial navigation system (SINS), odometer (OD), barometer and platform gravimeter. The SINS/OD /barometer integrated navigation solution delivers high-precision navigation parameters, completes the calculation of correction terms, and performs the autonomous dynamic gravity anomaly measurement combined with the primary measurement results of the platform gravimeter. Numerical calculations provide the requirements for the application of the proposed method, and the cut-off frequency for extracting gravity anomalies is 0.02 Hz, as determined by power spectral density analysis. In order to further improve the measurement accuracy and account for dynamic errors caused by vehicle maneuvering, a long-short-term memory (LSTM) model of recurrent neural network (RNN) is introduced. A series of experiments under multiple circumstances with repeated lines were conducted in Tianjin, China, and the static measurements along the line were taken using CG-5 to provide true values of gravity anomalies. The results demonstrate that the autonomous measurement scheme can achieve accuracy comparable to GNSS-assisted, and that dynamic error compensation algorithm based on LSTM improves the dynamic gravity measurements accuracy significantly without sacrificing the spatial resolution of gravity anomalies.

A power-efficient fast-transient OCL-LDO with adaptive super source follower and active capacitor compensation management

This paper presents a flipped voltage follower (FVF) based output-capacitor-less low-dropout regulator (OCL-LDO) with fast transient response, high power supply rejection (PSR), and low quiescent current for noise-sensitive circuits in internet-of-things (IoTs). An adaptive super source follower (ASSF) is proposed to effectively reduce the output impedance of the voltage buffer under heavy-loading conditions while keeping a low quiescent current under light-loading conditions. The active capacitor compensation management (ACCM) is proposed to solve the charge-sharing problem caused by the floating capacitors in the dynamic capacitor compensation circuit. The proposed OCL-LDO has been designed and fabricated in 22-nm CMOS technology. It can stabilize with load current ranging from 0 to 12 mA while consuming only 4.8-μA quiescent current. when the load current steps from 0.1 to 10 mA within 3.8 ns, the measured voltage undershoot is 55 mV and the recovery time is about 60 ns.

A dynamic thermal radiation insulation method for directional solidification of polysilicon

To simplify the structure and reduce the high energy consumption of thermal insulation structures for polysilicon directional solidification equipment, an innovative cavity structure with a mirror and diffuse reflector was designed for thermal insulation. This method uses an internal thermal radiation cavity instead of a traditional insulation layer. Compared with the traditional insulation material, its volume was only 16.6 % of the crucible volume, and the energy consumption was reduced by 8.6 %. A mathematical model of the thermal radiation exchange in the cavity was established and solved analytically. Because of the design of mirror and reflector, the self-adjustment of the thermal radiation intensity and angle in the cavity was theoretically verified. It could automatically “trail” the temperature change on the sidewalls of the melt (crucible), and the dynamic thermal compensation was equivalent to an adiabatic construction. Three comparison experiments with a large ingot (0.9 m × 0.9 m × 0.35 m) were performed. When the cavity height to width ratio was greater than 3.33, the thermal compensation was poor and the quality of the ingot is lower than that of the others. The experiments showed that refractory brick and polished brass are a good combination for creating a cavity.

Abrasive Waterjet Machining.

The abrasive waterjet machining process was introduced in the 1980s as a new cutting tool; the process has the ability to cut almost any material. Currently, the AWJ process is used in many world-class factories, producing parts for use in daily life. A description of this process and its influencing parameters are first presented in this paper, along with process models for the AWJ tool itself and also for the jet-material interaction. The AWJ material removal process occurs through the high-velocity impact of abrasive particles, whose tips micromachine the material at the microscopic scale, with no thermal or mechanical adverse effects. The macro-characteristics of the cut surface, such as its taper, trailback, and waviness, are discussed, along with methods of improving the geometrical accuracy of the cut parts using these attributes. For example, dynamic angular compensation is used to correct for the taper and undercut in shape cutting. The surface finish is controlled by the cutting speed, hydraulic, and abrasive parameters using software and process models built into the controllers of CNC machines. In addition to shape cutting, edge trimming is presented, with a focus on the carbon fiber composites used in aircraft and automotive structures, where special AWJ tools and manipulators are used. Examples of the precision cutting of microelectronic and solar cell parts are discussed to describe the special techniques that are used, such as machine vision and vacuum-assist, which have been found to be essential to the integrity and accuracy of cut parts. The use of the AWJ machining process was extended to other applications, such as drilling, boring, milling, turning, and surface modification, which are presented in this paper as actual industrial applications. To demonstrate the versatility of the AWJ machining process, the data in this paper were selected to cover a wide range of materials, such as metal, glass, composites, and ceramics, and also a wide range of thicknesses, from 1 mm to 600 mm. The trends of Industry 4.0 and 5.0, AI, and IoT are also presented.

Macro-micro synchronization strategy based on fuzzy time-delay compensation for high-precision laser on-the-fly processing

Real-time control systems of macro-micro manipulators commonly confront time-delay challenges to achieve high precision and synchronization performance, because macro and micro subsystems always have significant difference mainly in mechanical inertia. In this paper, a self-designed PC-based real-time controller utilized in laser on-the-fly processing is introduced as a study case of macro-micro systems. A dynamic time-delay compensation method for this case is proposed based on efficient fuzzy-model prediction and special data compression/extension algorithm. This method takes account of the practical time-delay fluctuation and has capability of adjusting the compensator adaptively rather than fixing the compensator as a constant, compared with the conventional static compensation. Experimental results show that, after applying the dynamic compensation, the process error caused by time-delay is eliminated from 1.059 mm to 0.001 mm, while the quality of synchronization appears even better than the static compensation with the error of 0.014 mm. Besides, the proposed method is computationally optimized, and the extra load of real-time kernel merely fluctuates within 3 % of the total computation performance capacity.

Analysis of DC Bias in Magnetic Controlled Shunt Reactor and Its Influence on Interturn Protection

Abstract Magnetic controlled shunt reactor is widely used in new energy transmission, and its special operation characteristics provide dynamic reactive power compensation for the power system, while the reactive power capacity can be continuously adjusted, solving the problem that conventional fixed reactance cannot be applied to reactive power demand fluctuations. This paper briefly introduces the structure and working principle of a magnetic controlled shunt reactor, analyzes the relationship between core magnetic saturation and control current in a magnetic controlled reactor under different DC bias conditions, and the reliability of interturn protection under different working conditions is studied and a feasible scheme is proposed, provides a certain reference for the design and operation and maintenance of magnetic controlled shunt reactor.

Effect of cutting tools and dynamic primary compensations on the working performance of contactless energy transfer system for rotary ultrasonic machining

In rotary ultrasonic machining, contactless energy transfer (CET) unit transmits electric energy from an ultrasonic power supply to a transducer, which converts the energy into ultrasonic vibration of the tool. Compensation enhances this transmission efficiency. However, the tool varies under different working conditions, changing the working performance of contactless energy transfer system (CETS), and fix compensation decreases CETS working performance under different tool parameters. To investigate the impact of tool size and dynamic compensations on CETS working performance, the equivalent-circuit models of CETS with dynamic primary compensations are developed, including dynamic primary series and parallel compensations, and examines the effect of tool on the transducer parameters. Subsequently, the effect of dynamic primary compensations and their variations on the CETS frequency characteristics, the influence of tool parameters and dynamic primary compensation variations on CETS transfer performance, and the sensitive analysis of CETS transfer performance on tool parameters and dynamic primary compensations are investigated. Finally, the experiment is conducted to validate the effects of tool and dynamic primary compensations, and the experimental results are consistent with the analysis above. Furthermore, the experiment also shows that a large tool extension can ensure the energy transmission of cutting tool, the dynamic primary series and parallel compensations are suitable options considering the stable output of ultrasonic power supply and load detection of transducer, respectively.

Achieving safe minimum circle circumnavigation around multiple targets: a dynamic compensation approach

Minimum circle circumnavigation is proposed in this paper, which is of special value in target monitoring, capturing and/or attacking. With this new pattern, our goal is to steer one agent to enclose multiple targets along a safe and minimum circular orbit with the desired tangential speed. This is achieved by a control protocol with dynamic compensators, which is also capable of avoiding collision between the agent and the multiple targets during the whole operational process. The control protocol is further extended to the scenarios of multiple agents circulating a group of targets by adding a coordination mechanism into the tangential velocity term, which allows the agents to distribute evenly on each expected circular orbit with the same or different radius. Simulations results illustrate the effectiveness of the proposed methods.

Dynamic Compensation of Distorted Measured Forces Using Improved Luenberger Observer

Dynamic Compensation of Distorted Measured Forces Using Improved Luenberger Observer

Adaptive Robust Control of Uncertain Euler-Lagrange Systems Using Gaussian Processes.

This article proposes a novel adaptive robust control approach based on Gaussian processes (GPs) for the high-precision tracking problem of uncertain Euler-Lagrange (EL) systems with time-varying external disturbances. Given a prior dynamic model, the GP regression (GPR) technique is employed to obtain a nonparametric data-based uncertainty model, including its probabilistic confidence intervals. Based on the adaptive sliding mode control (ASMC) framework, the posterior means of GPs are utilized for dynamic compensation, whereas the posterior variances are applied to adjust the feedback gains. This proposed control strategy is robust against significant system uncertainty with low feedback gains. A novel adaptive law for updating hyperparameters based on tracking error feedback is presented, thereby improving the performance of both tracking control and GP modeling simultaneously. Compared to existing likelihood-based optimization methods, this hyperparameter adaptive law enables data-efficient and fast uncertainty learning for control applications. The proposed control strategy guarantees the semiglobal asymptotic convergence to zero tracking error with a specified probability. Simulations using an underwater robot model demonstrate that the utilization of GPs and hyperparameter adaptive law significantly improves the performance of tracking control and uncertainty learning.

Style Generative Adversarial Network Combined with Dynamic Fundamental Frequency Difference Compensation: A Practical and Efficient Method for Emotional Voice Conversion

This paper explores a novel emotional voice conversion (EVC) method based on the style generative adversarial network combined with dynamic fundamental frequency difference compensation. On the one hand, in terms of spectrum mapping, based on the method of EVC using star generative adversarial network, we propose to replace one-hot vectors with the emotion style features extracted from spectrum to represent emotional information. It enables the conversion not only to fully learn emotion style from the target speech, but also to transfer unseen emotion styles to a new utterance, that is, one-shot EVC. On the other hand, given that the traditional logarithm Gaussian normalization transformation and its some variants for prosody transfer are not enough to reflect the fine-grained fundamental frequency distribution difference between the different emotional speech, we propose the improved strategy of dynamic fundamental frequency difference compensation. The experimental results show that our proposed method can accomplish high quality one-shot EVC, significantly outperforming the baseline in terms of speech quality and emotional saturation in both objective and subjective evaluations.

Transferring time and frequency signal through phase compensated telecommunication fibres

Precise time and frequency signal transfer over White Rabbit Precision Time Protocol (WRPTP) based underground optical fibre link has been experimentally demonstrated for its potential enhancement and better signal integrity. In order to prove its advantages in practical applications, the time synchronization performance of WRPTP-based underground telecommunication optical fibre links have been examined in controlled environment conditions as well as in varying ambient conditions. Under controlled environment conditions, time synchronization has been achieved within ± 100 ps uncertainty but variation in ambient conditions degrades the stability as well accuracy of the time transfer link. The introduction of active phase variation compensation enhances the accuracy by ∼ 66 % of the WRPTP-based underground time transfer link. The link’s instability in terms of Modified Allan deviation reaches to 2.0 E -15 from 7.5 E -15 at 4096 s of integration time which indicate that dynamic phase variation compensation improves the stability of WRPTP-based time transfer link under varying ambient conditions.

Dynamic error prediction and link strain feedback control for a novel heavy load multi-DOF envelope forming machine

Thin walled and high rib components (TWHRC) are widely used for rocket cabins, aircraft wings, panels and frames in aerospace equipment as critical load bearing structures. This paper is aimed to develop a novel multi-DOF envelope forming machine (MEFM) with parallel kinematic mechanism (PKM) to realize efficient manufacturing of TWHRC with high performance. Since the heavy load MEFM with PKM has many total differences with the light load PKM, such as dynamic error and precision control, this paper conducts research on dynamic error prediction modelling and precision control method for this novel heavy load MEFM.Firstly, the configuration of MEFM is developed and the kinematic model of MEFM is established. Then, a RFC (rigid-flexible coupling) and RFE (rigid finite element) coupling dynamic model of MEFM is established considering time-variation of kinematic configuration caused by large deformation of all the kinematic elements. Based on the dynamic model, the dynamic deformation and error of MEFM are predicted and their generation mechanisms are revealed. It is found that the linear compression deformation of two-force links is the largest among all the kinematic elements, and it is the most sensitive to the heavy forming load and the most insensitive to the installation error of strain gauges, thus suiting for the feedback of large deformation of MEFM. Based on the above findings, a novel link strain feedback and dynamic error compensation control method is proposed. Finally, experiments under different control methods are conducted, showing that the motion precision of envelope tool and forming precision of formed components under the proposed control method are remarkably improved compared with that under the traditional control method (The geometric deviation of formed components under the proposed control method is remarkably reduced to −18 ∼ 32um from −64 ∼ 54um under the traditional control method). The experimental results verify that the proposed dynamic error prediction model and link strain feedback control method for heavy load MEFM are reasonable.

Dynamic compensation of active and reactive power in distribution systems through PV-STATCOM and metaheuristic optimization

This article presents a heuristic methodology to address the operation problem of PV-STATCOMs, focusing on the dynamic compensation of active and reactive power to minimize daily energy losses and costs associated with purchasing energy in distribution networks. The methodology is developed using a master-slave type optimization approach. In the master stage, potential solutions are generated using an optimization algorithm based on the salp swarm. In contrast, the slave stage evaluates these solutions using the power flow method by successive approximations. The methodology was evaluated in two test systems, with 33 and 69 nodes, varying the power factor of each PV-STATCOM. The results demonstrate a significant reduction in both energy losses in the network and the cost of purchasing energy at the substation. Furthermore, the efficiency of the salp swarm algorithm for effective resolution of the problem is confirmed. This approach contributes to optimizing the operation of PV-STATCOMs and highlights the proposed algorithm's applicability and effectiveness in practical distribution network environments.

Common-Ground-Type Inverter With Dynamic Boosting and Reactive Compensation for Grid

Common-Ground-Type Inverter With Dynamic Boosting and Reactive Compensation for Grid