Driver Control Research Articles

Fuzzy self-tuning PID control of MC3 LLC resonant LED drivers

An MC3 LLC resonant light-emitting diode (LED) driver is a multi-channel constant current (MC3) output solution based on LLC resonance. Through an effective combination of multiple transformers and a DC block capacitor, this driver allows constant current outputs in multiple channels when the LED channels are unbalanced. This study considers a fuzzy self-tuning proportional integral derivative (PID) control strategy that allows for the self-tuning of PID parameters according to fuzzy inference rules designed using the relationship between the current gain and the switching frequency. Thus, when LED channels are unbalanced, the system allows a constant current output for each of the channels and controls the input voltage disturbances well. Simulation and experimental verifications are carried out, and a 20 W 4-channel constant current power supply design based on LLC resonance is obtained for the LED driver. This realizes soft-switching of the switching device, which reduces system loss and improves system efficiency. Moreover, the adjustment time of the proposed method is half that of fixed-parameter control methods, and the overshoot of the proposed method is smaller than that of fixed-parameter control methods. When compared with PID controllers with fixed parameters, the proposed method is more robust. When a system is disturbed, it recovers faster and has a smaller range of current fluctuation with the proposed method.

Modeling driver behavior in the dilemma zone based on stochastic model predictive control.

Driver behavior is considered one of the most important factors in the genesis of dilemma zones and the safety of driver-vehicle-environment systems. An accurate driver behavior model can improve the traffic signal control efficiency and decrease traffic accidents in signalized intersections. This paper uses a mathematical modeling method to study driver behavior in a dilemma zone based on stochastic model predictive control (SMPC), along with considering the dynamic characteristics of human cognition and execution, aiming to provide a feasible solution for modeling driver behavior more accurately and potentially improving the understanding of driver-vehicle-environment systems in dilemma zones. This paper explores the modeling framework of driver behavior, including the perception module, decision-making module, and operation module. The perception module is proposed to stimulate the ability to perceive uncertainty and select attention in the dilemma zone. An SMPC-based driver control modeling method is proposed to stimulate decision-making behavior in the dilemma zone. The operation module is proposed to stimulate the execution ability of the driver. Finally, CarSim, the well-known vehicle dynamics analysis software package, is used to verify the proposed models of this paper. The simulation results show that the SMPC-based driver behavior model can effectively and accurately reflect the vehicle motion and dynamics under driving in the dilemma zone.

The effects of technological supervision on gig workers: organizational control and motivation of Uber, taxi, and limousine drivers

Does supervision from technological platforms alter gig workers’ motivation and perceptions of control? We address this question with two field studies set in the passenger livery (pick up and drop off) industry. A between-subjects field survey (n = 50) finds that UberX drivers perceive significantly greater organizational control compared to taxi drivers, but do not report significantly different levels of intrinsic motivation, needs satisfaction, or enjoyment of work. In a follow-up within-subjects field experiment (n = 79), we identify the causal impact of technological supervision on drivers’ perceptions of control and motivation. Black car limousine drivers who sometimes work on the UberBlack platform are randomly assigned to respond to questions about their perceptions while driving either for Uber or their limousine company. Limousine drivers in the Uber condition report greater market control and enjoyment of the work. We draw several conclusions: 1) large differences between gig workers and incumbent workers are selection effects, and 2) Uber’s platform modestly increases perceptions of market control and task enjoyment with 3) no impact on motivation or needs satisfaction. This article contributes to the literature on the classification of gig workers, the gamification of work, and studies of technology, management, and organizations. We call for greater theoretical attention to how workers experience technological supervision and discuss how platforms change the future of employment relationships and human resource management.

Study on high-speed stability of automobile based on aerodynamic lift feedback

For a long time, the impact of aerodynamic lift on the stability of high-speed vehicles has been studied only from the perspective of the aerodynamic force, and there is a lack of quantitative assessment of the vehicle body. In this paper, a model of multi-body dynamics of the vehicle was constructed by using an in-use vehicle model as the research object. Accuracy was verified using computational fluid dynamics (CFD) and compared with HD-2 (the second wind tunnel of Hunan University) wind tunnel test data. The stability of the vehicle under the condition of high-speed driving was analysed from two aspects of body acceleration and lateral displacement. The results show that the aerodynamic lift at high speed will reduce the maximum lateral acceleration and the maximum yaw acceleration of the vehicle body in the obstacle avoidance condition; and reduce the response speed of the vehicle body to driver's control. The anti-floating front bumper can effectively reduce aerodynamic lift and improve the high-speed driving stability of the vehicles.

Mechanical properties and microstructural characteristics of rotary friction welded dissimilar joints of rolled homogeneous armor steel and medium carbon steel

Abstract Distinct materials are used for the construction of battle tanks used in defense sectors. The hull and turret of the battle tanks are made up of rolled homogeneous armor steel (also known as armor steel). The inner portions like the driver cabin and control room are covered with medium carbon steel. Hence, the dissimilar joint between these materials is unavoidable in the battle tank construction. Conventional fusion welding processes like manual metal arc welding, gas metal arc welding, and gas tungsten arc welding are preferred to join the dissimilar metals. However, the high heat input nature of these processes will create hydrogen induced cracking, high residual tensile strain, and HAZ softening, etc. To minimize these issues, solid state welding processes were adopted. In the present study, mechanical properties and microstructural characteristics of rotary friction welded dissimilar joint of armor steel and medium carbon steel was analyzed. The ultimate tensile strength of the dissimilar joint is around 775 MPa and the failure occurred at the medium carbon steel side. The impact toughness value of dissimilar joints is higher than medium carbon steel and lower than armor steel. The microstructure across the dissimilar joint has distinct features and a complex pattern was observed at the weld interface.

Energy-efficient inverter circuit for the low-voltage asynchronous driver controller with autonomous power supply

The design of the energy-efficient inverter circuit for the asynchronous frequency-controlled three-phase electric driver with autonomous low-voltage DC power supply. The components analysis of the electric drive, the main components selection approach: microcontroller, three-phase driver and power transistors. R&D prototype of the energy-efficient inverter circuit was created, characterized by an average consumption current reduced by 5%. Reducing energy losses is achieved by reducing dynamic losses in the power circuits of a low-voltage inverter and using several circuit solutions.

Needle Driver Control for a Robotic MIS Suturing System

Autonomous robotic suturing has attracted research attention for years. Few results have shown the performance of an integrated robotic arm with a needle driver. This research introduces a coupling mechanism to connect a Da Vinci® large needle driver to a six-axis robotic arm. The motion of the needle driver wrist is treated as two additional motion degrees-of-freedom for the robot to simultaneously maintain the remote center-of-motion (RCM) and the needle path. The experiment employed the augmented state approach for the RCM generation and formulated the desired needle trajectory into the task control framework. This framework enables the implementation of a common robot controller. A trajectory correction procedure is also introduced to correct for the error resulted from the wrong gripper dimensions. With the proposed system, the experimental results on a training phantom show a successful tracking of the predefined suturing path.

A Two-Layer Potential-Field-Driven Model Predictive Shared Control Towards Driver-Automation Cooperation

This paper proposes a novel driver-automation shared control based on a potential-field-driven model predictive controller (PF-MPC) and a two-layer fuzzy strategy (TLFS) to address driver-automation conflicts and control authority allocation issues. The PF-MPC approach based on the driver-vehicle model is introduced to deal with obstacles avoidance and driver-automation conflicts. The potential field is constructed to evaluate the driving risk by considering the driving environment and vehicle states, meanwhile, it is also involved in the optimized objective in the PF-MPC controller for obstacle avoidance. The tuning weight is designed to adjust the trade-off between the motion planning-related cost and driver-related cost to reduce driver-automation conflicts. To further alleviate the conflict and control authority allocation between the human driver and PF-MPC controller, the TLFS for shared control is designed based on the evaluation of the driving risk level and conflict situation, and the values of the tuning weight and cooperative coefficient are determined using the fuzzy control method. Moreover, comparative studies are conducted to verify the driving safety and conflict management performance of the proposed shared control method on a straight road and a curvy road. The results show that the proposed shared control method can help drivers avoid obstacles safely and alleviate the driver-automation conflicts in different driving conditions.

A Cascaded Gate Driver Architecture to Increase the Switching Speed of Power Devices in Series Connection

This article presents a cascaded gate driver (CGDA) architecture to improve the switching speed of series-connected power devices. The main idea is to propose a new technique to increase dV/dt of the devices when their voltages are already balanced. In complex power converters such as multicell and multilevel topologies, and series-connected power devices, many driver circuits are required and implemented. In such converters, there are several dV/dt sources generated at different floating points associated with the parasitic capacitances of the isolated barriers of the gate drivers (supplies and control signal isolation units), which can amplify the conducted electromagnetic interference (EMI) perturbations, and therefore, the switching speed of the power devices can be affected. This article is focused on the analysis of a new cascaded configuration of gate drivers to increase the switching speed and, consequently, reducing the switching losses of the series-connected transistor topologies. This improvement is achieved by reducing the equivalent parasitic capacitance of the gate driver circuitry considering the gate driver architectures: a new concept of cascaded gate driver is presented. Theoretical and experimental measurements are used to support the cascade gate driver architecture proposed in this article.

A novel gate driver for Si/SiC hybrid switch for multi‐objective optimization

A novel gate driver with simple functional and structural integration is proposed here, which splits the input gate signal and outputs two separate signals with a dedicated delay time to drive the two constitutional switches, aiming at the cost-effectiveness and power loss reduction of the Si/SiC hybrid switch. The dependency of the hybrid switch's thermal and efficiency performance on the parameters of the gate driver are theoretically and experimentally investigated in a 9 kW 20 kHz Si/SiC hybrid switch based boost converter. A novel load current dependent gate control strategy is proposed to be implemented in the proposed gate driver to achieve the high conversion efficiency under light to medium load condition and balanced junction temperature between the two internal devices under heavy load conditions. The experimental results based on a 20 kHz boost converter show that the Si/SiC hybrid switch with the novel gate driver and optimal current dependent control strategy offers a 163% and 10% rise in power handling capability, respectively, compared to that using the all-IGBT device and all-SiC MOSFET device, and yet a considerably lower device cost.

Інформаційно-розрахунковий комплекс «Тягові розрахунки» та математичні методи пошуку основних параметрів руху поїзда як основи оптимізації витрат ресурсів на тягу

The article deals with the issues of determining the main parameters of traction calculations and presents formulas for the mathematical apparatus of their search. A method for finding the distribution of specific traction forces and intervals of their action at selected calculation polygons and rationalizing the application of the driver's controller position relative to the locomotive speed is presented. The necessity of applying algorithmization based on the fuel efficiency of traction rolling stock is economically proved by comparative characteristics of rationing fuel consumption by a diesel locomotive, on a selected shoulder with a train of the appropriate weight, with values obtained as a result of the operation of the software package. The software product "traction calculations" in the programming language "C#"is presented. The calculation algorithm and its description are given with logically corresponding examples of the essence of the automated system. The basis of this software product is the law of conservation of mechanical energy, as an expression that takes into account all the factors of influence of external and internal circumstances on the train and its equations of motion. Graphically, the parameters of the movement of a freight train are interpreted in the form of curves of the dependence of time, speed, current of traction electric motors on the distance traveled and the conversion of calculations to the Microsoft Office Excel format as the basis for the optimization calculation of engineering and management apparatus.

Theoretical and experimental investigation of driver noncooperative-game steering control behavior

This paper investigates two noncooperative-game strategies which may be used to represent a human driver's steering control behavior in response to vehicle automated steering intervention. The first strategy, namely the Nash strategy is derived based on the assumption that a Nash equilibrium is reached in a noncooperative game of vehicle path-following control involving a driver and a vehicle automated steering controller. The second one, namely the Stackelberg strategy is derived based on the assumption that a Stackelberg equilibrium is reached in a similar context. A simulation study is performed to study the differences between the two proposed noncooperative-game strategies. An experiment using a fixed-base driving simulator is carried out to measure six test driver's steering behavior in response to vehicle automated steering intervention. The Nash strategy is then fitted to measured driver steering wheel angles following a model identification procedure. Control weight parameters involved in the Nash strategy are identified. It is found that the proposed Nash strategy with the identified control weights is capable of representing the trend of measured driver steering behavior and vehicle lateral responses. It is also found that the proposed Nash strategy is superior to the classic driver steering control strategy which has widely been used for modeling driver steering control over the past. A discussion on improving automated steering control using the gained knowledge of driver noncooperative-game steering control behavior was made.

Self-tuning fuzzy PID controller for servo control of hard disk drive with time delay

This paper presents the implementation of conventional proportional-integral-derivative (PID) controller, fuzzy logic with proportional-derivative (FL-PD) control configuration and self-tuning fuzzy logic PID (STFL-PID) controller for servo control of hard disk drive (HDD). Comprehensive performance analyses of the conventional PID, FL-PD and STFL-PID controllers are performed, and identify the superior control technique for the HDD. It is shown that the proposed and designed control technique improves the track seeking performance. The proposed controller is used to keep the read/write (R/W) head on track i.e., to minimize the position error signal (PES).

Multichannel sequential display LED driver with optimal transient performance and efficiency via synchronous integral control

This study proposes a high performance multichannel sequential display light emitting diode (LED) driver with pulse width modulated dimming control. A synchronous integral control strategy is developed for achieving optimal transient performances for the channel voltages and ideal rectangular waveforms for the LED current, which will help to maintain high efficiency and extend the lifetime of the LEDs. By synchronous integral control, each channel has a corresponding integrator whose input and output are turned on and off synchronously with the LED string. The proposed driver topology and control strategy are supported by detailed analysis on stability and transient response during on-time interval of a channel by using the averaged state-space model. The effectiveness of the design method is demonstrated with simulation. A three-channel LED driver is constructed to experimentally validate the high efficiency and high performance of the proposed topology and control strategy with desired LED current waveform and nearly constant channel voltages.

Evaluation of temporal consistency of snow depth drivers of a Rocky Mountain watershed in southern Alberta

AbstractCollecting spatially representative data over large areas is a challenge within snow monitoring frameworks. Identifying consistent trends in snow accumulation properties enables increased sampling efficiency by minimizing field collection time and/or remote sensing costs. Seasonal snowpack depth estimations during mid‐winter and melt onset conditions were derived from airborne Lidar over the West Castle Watershed in the southern Canadian Rockies on three dates. Each dataset was divided into five sets of snow depth driver classes: elevation, aspect, topographic position index, canopy cover and slope. Datasets were quality controlled by eliminating snow depth values above the 99th percentile value, which had a negligible effect on average snow depths. Consistent trends were observed among driver classes with peak snow accumulation occurring within the treeline ecotone, north‐facing aspects, open canopies, topographic depressions and areas with low slope angle. Although mid‐winter class trends for each driver were similar and watershed‐scale snow depth distributions were significantly correlated (0.76, p < .01), depth distributions within the same driver class of the three datasets were not correlated due to recent snowfall events, redistribution and settling processes. Trends in driver classes during late season melt onset were similar to mid‐winter conditions but watershed scale distribution correlation results varied with seasonality (0.68 mid‐winter 2014 and melt onset 2016; 0.65 mid‐winter 2017 and melt onset 2016, p < .1). This is due to the differing stages of accumulation or ablation and the upward migration in the 0°C isotherm during spring, when snow depth can be declining in valley bottoms while still increasing at higher elevations. The observed consistency in depth driver controls can be used to guide future integrated snow monitoring frameworks.

Parameter identification and robust vibration control of a truck driver’s seat system using multi-objective optimization and genetic algorithm

This paper has developed a 5-DOF driver and seat suspension system model for active vibration control. A novel fast system parameter identification method from vibration measurement data has been proposed for the seat-occupant system based on the multi-objective Genetic Algorithm optimization (GA). This system parameter identification method can identify the seat system parameters of a 5-DOF lumped mass-spring-dashpot biodynamic seat-occupant model from vibration test results quickly and accurately. Without calculation and measurement of materials, the physical parameters of the seat suspension system such as masses (m), stiffness (k), and damping coefficients (c) are estimated through matching the measured resonant frequency and transmissibility amplitude at a specific frequency with the simulated ones. This is one of the main contributions of this paper. The characteristics of the human body vibration in the low-frequency range are analyzed through the seat to head transmissibility (STHT) ratio. The experimental and simulation results of the STHT values have been calculated and compared to verify each other. The sensitivity analysis of the seat effective amplitude transmissibility (SEAT) values over the seat system parameters have been conducted and validated by the measured results of the transmissibility ratios. A full state feedback controller has been developed to reduce the human body vibration in the seat suspension system, which is another new contribution of this paper. The simulation results show that the proposed controller has better vibration attenuation performance than the conventional PID controller.

Light-Emitting Commutating Diodes for Optical Wireless Communications Within LED Drivers

Although visible light communication (VLC) systems provide high density links for use in Internet-of-Things (IoT) devices, the design of high rate VLC transmitters that maintain luminaire efficacy is an open problem. In this article, a novel approach to the integration of VLC within light-emitting diode (LED) drivers is proposed through the replacement of freewheeling/blocking diodes with light-emitting devices termed a light-emitting commutating diodes (LECDs). In this manner, communications and illumination can be provided using a simple, cost effective design while employing no additional components. The subtle change of LED driver control signals facilitates the transmission of data from LECDs while simultaneously supporting illumination functions. Lighting controls such as dimming are maintained and combined with modulation through the use of overlapping pulse position modulation (OPPM) and performance is quantified. Prototype buck and boost converters with LECDs are implemented and their efficacy is measured. Though current commercial LEDs are not intended for such signalling applications, we experimentally demonstrate their feasibility in this application and suggest methods to make such converters reliable. It is demonstrated that the addition of an LECD improves the efficacy of the luminaire as compared to conventional LED drivers while simultaneously enabling a VLC downlink.

Monolithic Integrated High Frequency GaN DC-DC Buck Converters with High Power Density Controlled by Current Mode Logic Level Signal

Integration is a key way to improve the switching frequency and power density for a DC-DC converter. A monolithic integrated GaN based DC-DC buck converter is realized by using a gate driver and a half-bridge power stage. The gate driver is composed of three stages (amplitude amplifier stage, level shifting stage and resistive-load amplifier stage) to amplify and modulate the driver control signal, i.e., CML (current mode logic) level of which the swing is from 1.1 to 1.8 V meaning that there is no need for an additional buffer or preamplifier for the control signal. The gate driver can provide sufficient driving capability for the power stage and improve the power density efficiently. The proposed GaN based DC-DC buck converter is implemented in the 0.25 μm depletion mode GaN-on-SiC process with a chip area of 1.7 mm × 1.3 mm, which is capable of operating at high switching frequency up to 200 MHz and possesses high power density up to 1 W/mm2 at 15 V output voltage. To the authors’ knowledge, this is the highest power density for GaN based DC-DC converter at the hundreds of megahertz range.

A Monolithic GaN-IC With Integrated Control Loop for 400-V Offline Buck Operation Achieving 95.6% Peak Efficiency

Gallium nitride (GaN) transistors enable efficient and compact high-voltage power converters. In the state-of-the-art enhancement mode GaN-on-Si technology, a 650-V power transistor is formed as a lateral structure enabling monolithic integration with a driver and analog control circuits on one die. Offline power converters show a trend toward a higher level of integration, shifting from monolithic silicon (CMOS) to various integration levels in GaN technology. In this article, a monolithic, self-biased GaN buck converter for offline operation is presented, supporting both 110- and 230-V ac line voltage and providing up to 29-W output power. The converter shows a superior efficiency of 95.6 % and a very high level of integration in a 650-V p-GaN gate e-mode GaN-on-Si technology. Analog design techniques for GaN integration, such as an auto-zero comparator and a high-voltage supply regulator, are discussed. Experimental results of stand-alone circuit blocks and the full buck converter confirm the viability of monolithic GaN integration as a path toward compact and efficient offline power converters.

Acoustic Search and Detection of Oil Plumes Using an Autonomous Underwater Vehicle

We introduce an adaptive sampling method that has been developed to support the Backseat Driver control architecture of the Memorial University of Newfoundland (MUN) Explorer autonomous underwater vehicle (AUV). The design is based on an acoustic detection and in-situ analysis program that allows an AUV to perform automatic detection and autonomous tracking of an oil plume. The method contains acoustic image acquisition, autonomous triggering, and thresholding in the search stage. A new biomimetic search pattern, the bumblebee flight path, was designed to maximize the spatial coverage in the oil plume detection phase. The effectiveness of the developed algorithm was validated through simulations using a two-dimensional planar plume model and a 90-degree scanning sensor model. The results demonstrate that the bumblebee search design combined with a genetic solution for the Traveling Salesperson Problem outperformed a conventional lawnmower survey, reducing the AUV travel distance by up to 75.3%. Our plume detection strategy, using acoustic sensing, provided data of plume location, distribution, and density, over a sector in contrast with traditional chemical oil sensors that only provide readings at a point.