Speed Command Research Articles

Foundry fabricated compact slow-light Mach-Zehnder modulator and photodetector for on-chip analog photonic computing.

This work presents a scaling pathway of on-chip analog photonic computing using foundry-fabricated silicon electro-optic (EO) slow-light Mach-Zehnder modulators (SL-MZMs) and compact Ge photodetectors (PDs) to construct a computing unit. Two SL-MZMs with phase shifter (PS) lengths of 500 μm and 150 μm are studied in this work. The bit resolution, nonlinearity, clock frequency, and power consumption of the photonic computing link, including an RF amplifier, on-chip SL-MZM, and a PD, are thoroughly investigated. The computing link using the SL-MZM with 500 μm has demonstrated a low normalized mean square error (NMSE) of 0.0305 at 8-bit resolution under 3.2 GHz clock frequency. Under the setting of 6-bit resolution at a clock frequency of 800 MHz, high computing accuracy was achieved with a measured NMSE of 0.0018 using the SL-MZM with 150 μm PS length. Using the Google Speed Commands dataset to run a voice keyword spotting task, we determine that 6-bit resolution operating at 3.2 GHz achieves the optimal power-accuracy trade-off. We show a 20× improvement in energy efficiency and a 3.35× improvement in area efficiency compared to NVIDIA V100 GPU ["Volta: Performance and programmability," IEEE Micro38(2), 42 (2018)10.1109/MM.2018.022071134]. These results show that our compact SL-MZMs and PDs promise to scale up photonic computing for practical machine-learning applications.

A Robust Controller Based on Extension Sliding Mode Theory for Brushless DC Motor Drives

This paper presents the design of a robust speed controller for brushless DC motors (BLDCMs) under field-oriented control (FOC). The proposed robust controller integrates extension theory (ET) and sliding mode theory (SMT) to achieve robustness. First, the speed difference between the speed command and the actual speed of the BLDCM, along with the rate of change of the speed difference, are divided into 20 interval categories. Then, the feedback speed difference and the rate of change of the speed difference are calculated for their extension correlation with each of the 20 interval categories. The interval category with the highest correlation is used to determine the appropriate control gain for the sliding mode speed controller. This gain adjustment tunes the parameters of the sliding surface in the SMT, thereby suppressing the overshoot of the motor’s speed. Because a sliding surface reaching law of the sliding mode controller (SMC) adopts the exponential approach law (EAL), the system’s speed response can quickly follow the speed command in any state and exhibit an excellent load regulation response. The simplicity of this robust control method, which requires minimal training data, facilitates its easy implementation. Finally, the speed control of the BLDCM is simulated using Matlab/Simulink software (2023b version), and the results are compared with those of the SMC using the constant-speed approach law (CSAL). The simulation and experimental results demonstrate that the proposed robust controller exhibits superior speed command tracking and load regulation responses compared to the traditional SMC.

Backstepping Control Design in Conjunction with an EKF-based Sensorless Field-Oriented Control of an IPMSM

The collector and brushless electronic commutation machines have gained widespread utilization in industrial applications. Among these machines, internal permanent magnet synchronous motors (IPMSMs) have become increasingly popular due to their numerous advantages, including high torque/current and torque/inertia ratios, robust construction, high efficiency, and reliability. However, the incorporation of position sensors in IPMSMs has introduced challenges concerning their application, performance, mass production, and cost. Consequently, the implementation of sensorless control techniques has become essential in drive systems and various applications. This paper proposes a backstepping control approach for achieving speed sensorless control of IPMSMs, employing an extended Kalman filter (EKF). The first step involves developing a comprehensive nonlinear dynamical model of the IPMSM in the direct and quadrature (d-q) rotor frame and obtaining its corresponding state-space representation. Subsequently, backstepping controllers for rotor speed and current tracking are designed to ensure precise tracking and anti-disturbance performance. These controllers are integrated into the field-oriented control (FOC) scheme. The Lyapunov stability theorem is employed to guarantee the asymptotic stability condition of the backstepping controller. To address the challenge of estimating immeasurable mechanical parameters of the IPMSM and accurately tracking the system states, an EKF is designed. This filter enables the estimation of mechanical parameters and achieves high steady-state precision within a finite time. The effectiveness of the proposed methodology is demonstrated through simulations conducted under various dynamic operating conditions, including sudden torque load changes, command speed changes, and parameter variations.

Intelligent robust control for aviation electric fuel pump based on second order integral sliding mode with UDE

This paper proposes an original intelligent robust control method for a kind of aviation electric fuel pump (AEFP) systems, in order to realize on-demand fuel supply for aircraft engines, accurately and robustly. By considering the feature of AEFP, the intelligent robust control method is in a cascaded structure, which combines a novel second order integral sliding mode control (SOISMC) approach with uncertainty and disturbance estimator (UDE) strategy, together with a new multi-objective variable speed grey wolf optimization algorithm (MOVSGWO). To let the current loop of AEFP possess both rapidity and robustness, the SOISMC is presented based on an innovative second order integral sliding mode manifold. To realize that AEFP has strong robustness to both the changing of speed command and the pulsation in fuel pump, UDE is utilized for the speed loop of AEFP. The primary parameters in the intelligent robust controller, namely, UDE-SOISMC controller, are optimized by MOVSGWO. The MOVSGWO is a modified grey wolf optimization algorithm with variable speed by particle swarm optimization. Mismatched uncertainties and disturbances in AEFP can be handled by the proposed robust method. The calculation of instantaneous flow and dynamic torque in AEFP is illustrated. Simulation and experimental results verify the effectiveness of the UDE-SOISMC method.

Indirect Field Oriented Control of Induction Motor

The various control strategies for the control of the inverter-fed induction motor have provided good steady-state but poor dynamic response. In the last decades, many control techniques have been developed providing good performance. Field-oriented control is one of the most significant control methods for high performance AC electric machines and drives. In particular, for induction machines, indirect field oriented control is a simple and highly reliable scheme which has essentially become an industry standard. With the advent of the vector control methods, an induction motor can be operated like a separately excited dc motor for high performance applications. The speed control is observed in closed-loop control applications. The speed regulation is achieved with a PI controller which converts the command speed into the command torque and therefore the speed of the drive. In this paper PI controller base indirect field orientation control of 3-phase 415V, 50Hz Induction motor using cascaded multilevel inverter is proposed in MATLAB/SIMMLINK 7.10.0 (R2010a).

Design, Simulation, and Prototype of an 18-Wheeler Electric Vehicle with Range Extension using Solar PV and Regenerative Braking

In response to California's initiative to propel the advancement of hybrid and electric vehicles toward achieving zero emissions, this study undertakes the design of a hybrid 18-wheeler aligning with the state's stringent standards. The motivation stems from the imperative need to address the research and development in the domain of hybrid/electric class 8 vehicles, specifically focusing on the pivotal segment of 18-wheelers. The research team developed a realistic theoretical design, verified it using MATLAB Simulink simulation, and ultimately built a prototype. The truck's novel features, namely, 60% electric power, regenerative braking, and solar PV for range extension, are included in the design and partially implemented in the prototype. Two motors, a DC and an AC, are used as the prototype drives where the system control is mostly automatic. Simulation of the electric 18-wheeler design shows that the model works properly. It follows the speed command closely while the acceleration and deceleration behaviors are normal. Testing of the prototype shows that it functions appropriately. The DC motor speed can be regulated over a wide speed range while the AC motor can run at two different speeds as designed. The prototype microcontroller logic is followed, ensuring safe operation of the solar PV system and the battery, and effective control of the motors. Overall, the project succeeded in achieving a harmonious blend of simulation, design, and physical implementation. It can be used as an engineering and public education tool. Further, by exploring cutting-edge technologies such as regenerative braking and solar power for truck range extension, the project contributes to raising vehicle efficiency and finding sustainable transportation solutions, which make the transportation sector more friendly to the environment.

Stability of input voltages of a three-level inverter NPC fed by photovoltaic sources

In this paper we study the stability of input voltages of the cascade consisting of a photovoltaic inverter and a three-level structure NPC, feeding a synchronous machine with permanent magnets (PMSM) commissioned by the speed command flow oriented. For this, we first present the modeling of the Photovoltaic, then modeling and strategy to control the inverter three-level structure NPC. In the end, to address the midpoint fluctuation and instability of input voltages at the terminals of the inverter, proposed a solution consisting of a bridge clamping which gave promising results.

Fuzzy logic based vector control of multi-phase permanent magnet synchronous motors

This paper presents a fuzzy-logic-based vector control for a five-phase permanent-magnet synchronous motor (PMSM). The high-performance of the proposed fuzzy logic control (FLC)-based PMSM drive are investigated and compared with the conventional proportional-integral (PI) controller at different conditions, such as step change in command speed and load, and robustness against machine parameter variations. Finally, Simulation results shows that FLC presents better performances and high robustness compared to the conventional PI controller.

Performance Analysis of Conventional IPMSM and NCPM Based IPMSM

This paper proposes a NCPM (Nano-composite coated permanent magnets)-based IPMSM (Interior Permanent Magnet Synchronous Motor) electric drive system, especially applicable for electric vehicles (EV). For an EV, an increase in the “T/A (torque per ampere)” condition is highly recommended, as it directly affects the maximum distance run by EV on a single charge. Due to NCPM, a substantial increase in magnetic flux intensity, resistance to corrosion and Curie temperature are observed. As a result, the proposed drive clearly exhibits a higher power to weight ratio. Also, it is capable of delivering higher T/A to the drive system without any considerable change in two important factors of EV: (1) mass and volume of the drive system (2) battery capacity of the drive system. Moreover, NCPM performance is less susceptible to temperature variation, which makes it an appropriate candidate for vehicular applications, where temperature inconsistency could be a common issue during working conditions. Also, NCPM-based IPMSM offers a quicker speed response than conventional IPMSM, thus providing higher acceleration, which is one of the important performance factors for vehicular applications. A vector controlled mathematical model of IPMSM and NCPM-based IPMSM is tested for various speed commands. Also, the NCPM-based IPMSM, in the proposed configuration, is fed from a three-level DCMLI (diode clamped multi-level inverter), as the drive system is considered for medium to high power applications. A comparative performance analysis is carried out between the proposed drive system and a conventional IPMSM-based drive system using MATLAB/SIMULINK to indicate the efficacy of the proposed configuration.

The Design of a Reaction Flywheel Speed Control System Based on ADRC

The reaction flywheel is a crucial operational component within a satellite’s attitude control system. Enhancing the performance of the reaction flywheel speed control system holds significant importance for satellite attitude control. In this paper, an active disturbance rejection control (ADRC) approach is introduced to mitigate the impact of uncertain disturbances on reaction flywheel speed control precision. The reaction flywheel speed control system is designed as an ADRC controller due to the current challenge of measuring unknown disturbances accurately in the reaction flywheel system. To derive the rotor’s speed observation value and the estimated total disturbances value, the sampled data of the reaction flywheel rotor position and torque control signal are fed into the extended state observer. The estimated total disturbances value is compensated on feedforward control, which could mitigate significantly the effects of various nonlinear disturbances. The paper initially establishes the rationale behind the reaction flywheel ADRC controller through theoretical analysis, followed by analysis of the differences of performance of reaction flywheel control by the ADRC controller and the PID controller in MATLAB/SIMULINK. Simulation results demonstrate the evident advantages of the ADRC controller over the PID controller in terms of speed command tracking capability and disturbances suppression ability. Subsequently, the ADRC controller program and the PID controller program are implemented on the reaction flywheel control circuit, and experiments are conducted to contrast speed command tracking and disturbance suppression. Importantly, the experimental outcomes align with the simulation results.

Airborne Separation Assistance during Landing - An Approach for Automation

Self-spacing and Required-Time-of-Arrival (RTA) concepts are now being developed to support future Air Traffic Management (ATM) systems. Among many types of separation methods, distance based separation assumes importance form safety point of view. The present study is an attempt to analyze approach proposed by EUROCAE and extend the same for development of guidance laws in the form of acceleration commands instead of speed commands. Objective is to realize an effective implementation of the guidance laws in the Thrust Management Function of onboard Flight Management System. Simulation studies are presented involving actual flight responses for the lead aircraft during terminal phase.

Reduction of Pressure Pulsation for Pump-Turbine by Variable Speed Operation

Abstract Variable speed operation has emerged as a key direction in the development of pumped storage technology. Maintaining pressure pulsation within the control range is particularly critical for ensuring operational safety of variable-speed pumped storage plants (VSPSPs). However, there is limited research on the relationship between pressure pulsation for pump-turbine and variable speed operation. This paper presents amplitude distribution diagrams of pressure pulsation, obtained from processing model test results of a real VSPSP. Different conditions of variable speed operation are simulated by a numerical model to analyze the influence of operating trajectory on pressure pulsation, and the intensity of pressure pulsation is quantitatively evaluated. According to the results, when the initial speed or speed command increases, the trajectory passes through more regions with high-amplitude pressure pulsation and gradually moves toward the S-shaped region, leading to pressure oscillations. When speed command reduces, maximum pressure pulsation at the volute inlet and in the draft tube can be reduced by 82.18% and 63.24% at most, and the evaluation score can be increased by 28.77%. The findings of this study can offer theoretical guidance for operating VSPSPs.

Speed-command-independent parameters self-tuning and mismatch compensation for servo speed control

Usually the servo system using the traditional generalized predictive control is limited by the reference command, the expression of which is only a step signal or a ramp signal. Meanwhile, during the identification convergence, the model mismatch composed of the modeling errors and the nonlinear disturbance, often leads to the obvious speed spike and even damping oscillation. To solve the above problems, a speed-command-independent 2 degree-of-freedom (2DOF) N-type PI (NPI) controller based on an improved generalized predictive control (IGPC) is designed, as well as an extended sliding-mode compensator (ESMC) is proposed in this paper. First, to enhance the steady-state performance for tracking speed command, a 2DOF NPI speed controller is utilized to track the arbitrary-order polynomial command. Then, based on the forward N-order difference operator, an extended prediction model, the output of which only contains the speed error, is established to free the IGPC from the speed command. Next, the optimal control law is obtained by the rolling optimization of a reconstructed cost function, and further is simplified to match with the 2DOF NPI controller online. Finally, the ESMC is designed to effectively weaken the speed spike caused by the model mismatch, and a special positive definite function is utilized to ensure its stability. Simulation and experimental results verify the advantages of the proposed scheme.

An Enhanced Nonlinear ADRC Speed Control Method for Electric Propulsion System: Modeling, Analysis, and Validation

The electric propulsion system is composed of permanent magnet synchronous motor (PMSM) equipped with propeller load. Due to the strong coupling of propeller speed and load torque, they considerably characterize dynamic response and disturbance suppression capabilities of the speed controller. Traditional nonlinear active disturbance rejection control (NADRC) is less effective in dealing with a step change of command speed and large disturbance. In order to provide faster response and stronger disturbance rejection potential, an enhanced NADRC strategy is proposed in this paper. Initially, a linear extended state observer (LESO) is applied to preliminary estimate the total disturbance. Then, using the designed weight regular function, this estimation is introduced into the nonlinear extended state observer (NESO) with a cascade structure. The convergence, stability and disturbance estimation performance of the proposed strategy are then analyzed. Finally, experimental validation is performed based on a constructed experimental platform. The results show that the proposed method reasonably enhances the speed response and anti-disturbance performances.

트랙션용 다자유도 구형 전동기의 구동을 위한 간접 벡터 제어 연구

The multi-degree-of-freedom spherical motor for traction has characteristics of rotation and steering. Although it is base on the rotation principle of an induction motor, only a spherical motor control method is required for rotation and steering. In order to estimate the speed command of the rotor, the mechanical angular velocity of the rotor is measured using an optical sensor, and the slip angular velocity is calculated with the current command of the d-q axis stator of the synchronous coordinate system. The rotor magnetic flux angle can be obtained in the above two ways, and through this, the vector control of the spherical motor is achieved. The desired magnetic flux component current and torque component current are distributed to operate the spherical motor. As such, the indirect vector control method has advantages in that it is simple to implement because it does not use the magnetic flux linkage of the rotor and that it is easy to operate from low speed to rated speed.

Self-paced heart rate control for treadmill exercise

Introduction: With conventional heart rate (HR) control systems, the exercising person is bound to walk or run at a pace determined by the feedback. This may be challenging for people with impairments that make it difficult for them to achieve a smooth, continuous pace. The aim of this work was to assess the technical feasibility of a novel self-paced heart rate control strategy and to compare its accuracy with conventional heart rate control.Methods: We propose a self-paced heart rate control system that embeds an automatic positioning controller within the heart rate control loop. The treadmill speed command is decoupled from the heart rate compensator, whereas speed is determined by the exerciser’s own volition: target speed is displayed visually to the person and, when they try to follow this target, the position controller sets the treadmill speed while keeping the person at a safe reference position on the track. A further novel contribution of this work is a new input-sensitivity-shaping, frequency-domain design strategy for feedback control of position.Results: Experimental evaluation with four participants showed that self-paced heart rate control is technically feasible: all participants were able to accurately follow the target running speed calculated by the HR compensator and presented to them visually; for all four participants, self-paced HR tracking accuracy was not substantially different from conventional HR control performance; on average, the self-paced heart rate controller gave slightly better performance than conventional HR control, with RMS tracking error of 2.98 beats per minute (bpm) vs 3.11 bpm and higher average control signal power.Conclusion: The proposed self-paced heart rate control strategy with embedded automatic position control is deemed feasible. This approach may be helpful for people with gait impairments or other limitations that make it difficult for them to follow an imposed treadmill speed.

Coordinated Vision-Based Tracking by Multiple Unmanned Vehicles

We address the problem of coordinated vision-based tracking of a moving target using multiple unmanned vehicles that exchange information over a supporting time-varying network. The objective of this work is to formulate decentralized control algorithms that enable multiple vehicles to follow the target while coordinating their phase separation. A typical scenario involves multiple unmanned aerial vehicles that are required to monitor a moving ground object (target tracking) while maintaining a desired inter-vehicle separation (coordination). To solve the vision-based tracking problem, the yaw rate of each vehicle is used as the control input, while the speeds of the vehicles are adjusted to achieve coordination. It is assumed that the vehicles are equipped with an internal autopilot, which is able to track yaw rate and speed commands. The performance of the coordinated vision-based tracking algorithm is evaluated as a function of the target’s velocity, tracking performance of the onboard autopilot, and the quality of service of the communication network.

Dynamic modeling and favorable speed command of variable-speed pumped-storage unit during power regulation

Variable-speed pumped-storage unit (VSPSU) has advantages in flexibility, efficiency, and reliability. It has become a state-of-the-art technology in pumped-storage industry. However, there is little research about the transient process of VSPSU working at a favorable speed command during power regulation. To study the issue, a refined model considering hydraulic–mechanical and electrical subsystems is built in this work. All submodels are created by the authors as individual modules on Simulink platform, and these modules can be easily combined to model different VSPSUs. For the VSPSU that uses a doubly fed induction machine and adopts the fast power control strategy, there are several speed constraints. To satisfy the speed constraints during transient process, the speed command is adjusted to avoid exceeding the allowable speed variation range and eliminate the oscillation caused by the S-shaped region, while being guided by the optimal speed to achieve higher efficiency. The faster the speed command changes, the more rapid the power regulation could be. But fast-changing speed command also leads to larger pressure fluctuations in penstocks. Hence, different schemes of the speed command are compared, and suitable schemes are proposed by comprehensively considering the balance between rapidity and safety. The dynamic model and analysis of favorable speed command can provide support and advice for engineering practice.

Straight-Path Following and Formation Control of USVs Using Distributed Deep Reinforcement Learning and Adaptive Neural Network

Dear Editor, This letter presents a distributed deep reinforcement learning (DRL) based approach to deal with the path following and formation control problems for underactuated unmanned surface vehicles (USVs). By constructing two independent actor-critic architectures, the deep deterministic policy gradient (DDPG) method is proposed to determine the desired heading and speed command for each USV. We consider the realistic dynamical model and the input saturation problem. The radial basis function neural networks (RBF NNs) are employed to approximate the hydrodynamics and unknown external disturbances of USVs. Simulation results show that our proposed method can achieve high-level tracking control accuracy while keeping a desired stable formation.

Dynamic Addition of Common Mode Voltage in Post Fault Operation of Cascaded H-Bridge Converter Fed Induction Motor Drive

In this article, a postfault control technique is proposed for a rotor field-oriented induction motor (RFO-IM) drive fed from a cascaded H-bridge multilevel (CHB-ML) converter. The control strategy is to vary the magnitude and phase shift of the injected fundamental common mode voltage (FCMV) according to the motor’s operating condition. The addition of the proposed FCMV with the reference phase voltages, not only ensures maximum line voltage in the postfault operating condition but also shares equal power among the remaining healthy cells of the converter. Moreover, in the postfault operation, a detailed analysis is performed on both motor and converter, and an integrated control is presented to maintain the command speed and load torque of the RFO-IM. This includes the mathematical equation explaining the new operating point of the motor for different fault configurations, traversal of operating point, and the variation in power factor of each leg of the converter in postfault conditions. From the above analysis, the dynamic FCMV is calculated from the new operating point of the stator current components in the current <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -plane and the fault configuration of the CHB-ML converter. The proposed control technique is validated using simulation and experimental results conducted on a 3-hp IM.