Design Of Driver Research Articles

Structural Estimation of Attrition in a Last-Mile Delivery Platform: The Role of Driver Heterogeneity, Compensation, and Experience

Problem definition: We examine how to manage turnover among drivers delivering parcels for last-mile platforms. Although driver attrition in these platforms is both commonplace and costly, there is little understanding of the processes responsible for this phenomenon. Methodology/results: We collaborate with a platform to build a structural model to estimate the effects of key predictors of drivers’ decisions to leave or remain at the platform. For this estimation, we apply a dynamic discrete-choice framework in a two-step procedure that accounts for unobserved heterogeneity among drivers while circumventing the use of approximation or reduction methods commonly used to solve dynamic choice problems in the operations management domain. Drivers are compensated using a combination of regular payments that reward their productivity and subsidy payments that support them as they gain experience on the job. We find that regular pay has a greater effect on drivers’ retention. Furthermore, the marginal effects of both regular and subsidy pay diminish with drivers’ tenure at the platform, but the latter diminishes faster than the former. Additionally, we find significant heterogeneity among drivers in their unobserved nonpecuniary taste for the jobs at the platform and a significantly greater probability of retention among drivers with greater taste for these jobs. Managerial implications: Platforms can leverage our results to improve driver retention and design more profitable payment policies. We perform counterfactual analyses and develop a modeling framework to guide platforms toward this goal. Funding: This study was partially funded by a grant from TForce Logistics. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2021.0367 .

Design of low ripple PWM voice coil motor driver

Design of low ripple PWM voice coil motor driver

Design and implementation of a full analogue gate driver for current compensation of paralleled SiC‐MOSFETs

AbstractSilicon carbide MOSFETs have current ratings that are not sufficiently high to be used in high‐power converters. It is necessary to connect several MOSFETs in parallel in order to increase current capabilities. However, transient imbalance peak currents during turn‐on and ‐off processes challenge the performance and reliability of parallel MOSFETs. This paper considers the impact factors of device parameters, asymmetrical power circuit layout and circuit parasitic analytically to reveal the imbalance current peaks. The turn‐on and ‐off transient conditions are studied and mathematically investigated. In master‐slave configuration, a fully analogue active gate driver is designed and implemented to suppress the imbalance current among parallel silicon carbide (SiC) MOSFETs. In the proposed scheme, by exploiting an imbalance current detection circuit and I‐controller in a negative feedback for the slave MOSFET, an appropriate control voltage is obtained. The output voltage of active gate driver is adjusted by the control voltage, whether positive or negative in turn‐on and ‐off transient, in order to synchronize the peak currents of paralleled modules. Moreover, a detailed circuit of the designed compensator is presented and discussed. The experimental results are presented to verify the reliability and the effectiveness of the proposed compensator.

Drivers’ reactions to real-world forward collision warnings at both macroscopic and microscopic longitudinal levels: A functional approach

Understanding drivers’ reactions to in-vehicle forward collision warnings (FCWs) is vital for advancing FCW design and improving road safety. However, past studies often used aggregated safety measures to analyze the drivers’ reactions to FCWs, thereby at the microscopic level, limiting our ability to understand drivers’ reactions to FCWs at particular timestamps immediately after FCWs are issued. Additionally, there has been a notable absence of studies at the macroscopic perspective focusing on analyzing how drivers’ reactions to FCWs evolve over an extended period of time. To overcome these two limitations, this study proposes a new research framework using Functional data analysis (FDA) approach to model driver behavior profile in response to FCWs at both microscopic and macroscopic longitudinal levels. Real-world FCW data collected from the New York City Connected Vehicle Pilot Deployment project is used for the case study. At the microscopic level, a sparse functional design is adopted to model driver behavior profiles, accounting for irregularly spaced functional measurements. Nonparametric functional linear regression is then used to estimate the drivers’ reactions to FCWs at a particular timestamp immediately after FCWs are issued. At the macroscopic level, the functional two-sample test and a functional distance metric are used to examine changes in drivers’ reactions to FCWs over the study period and quantify the magnitude of these changes. Time to collision (TTC) and modified time to collision (MTTC) measures are used to represent driver behavior profiles, and both TTC and MTTC after FCWs are issued are modeled as functions with respect to time based on the proposed FDA approach. Compared to using aggregated safety measures including minimum TTC and MTTC as well as mean TTC and MTTC, new patterns of drivers’ reactions to FCWs are unveiled at both microscopic and macroscopic longitudinal levels. Study outputs reveal several key insights, including driver compensation behavior that escalates safety risk after an initial safety improvement and the diminishing safety benefits of FCWs from the beginning to the end of the after period. The proposed research framework can be generalized to analyze various types of in-vehicle driver warnings at both microscopic and macroscopic longitudinal levels. The findings of this study can support the calibration of detailed driver response behavior to in-vehicle warnings and facilitate the design of driver warning applications and further investigation of their safety benefits.

Design of Small Permanent-Magnet Linear Motors and Drivers for Automation Applications with S-Curve Motion Trajectory Control and Solutions for End Effects and Cogging Force

This paper designs and fabricates a small-type permanent-magnet linear motor and driver for automation applications. It covers structural design, magnetic circuit analysis, control strategies, and hardware development. Magnetic circuit analysis software JMAG is used for flux density distribution, back electromotive force (back-EMF), and electromagnetic force analysis. To address the lack of a complete closed magnetic circuit path at the ends of the linear motor, which causes magnetic field asymmetry, a phenomenon known as end effects, auxiliary core structures are proposed to compensate for the magnetic field at the ends. It successfully utilizes auxiliary cores to achieve the phase voltages of each phase, which are balanced at a phase voltage error of 0.02 V. To address the cogging force caused by variations in the magnetic reluctance of the core, this paper analyzes the relationship between electromagnetic force and mover position, conducting harmonic content analysis to obtain parameters. These parameters are applied to the designed cogging force control compensation strategy. It successfully achieves q-axis current compensation of around 1.05 A based on the mover’s position, ensuring that no jerking caused by cogging force occurs during closed-loop electromagnetic force control. The S-curve motion trajectory control is proposed to replace the traditional trapezoidal acceleration and deceleration, resulting in smoother position control of the linear motor. Simulations using JMAG-RT models in MATLAB/Simulink verified these control strategies. After verification, practical test results showed a maximum position error of approximately 5.0 μm. Practical tests show that the designed small-type permanent-magnet linear motor and its driver provide efficient, stable, and high-precision solutions for automation applications.

Sub-volt forward-biased silicon microring modulator at 210 Gb/s.

Low-voltage and efficient optical modulators in the silicon photonic (SiPh) platform are highly desired for realizing high-speed connectivity in chip level interconnects, data center interconnects, and high-performance computing (HPC). With the modulator operating at CMOS compatible voltages, high-voltage modulator drivers are no longer needed, thus reducing driver design complexity and power consumption. We demonstrate a silicon microring modulator (MRM) operating at a driving voltage of 0.8 Vpp. We achieve high modulation efficiency by using a small forward bias of 0.2 V: the forward bias voltage allows the modulator to have an enhanced optical modulation amplitude (OMA) by operating near injection mode, modulating 180 Gb/s (180 Gbaud) non-return-to-zero (NRZ) and 210 Gb/s (105 Gbaud) 4-level pulse amplitude modulation (PAM-4) free of electrical or optical amplification. We also demonstrate the operation at zero bias and achieve up to 200 Gb/s. Error-free operation was observed at 130 Gb/s (NRZ). The absence of an external biasing voltage can further improve energy efficiency and simplifies device integration.

High-frequency shear wave MR elastography of parotid glands: custom driver design and preliminary results.

Parotid glands are one of the most common sites for salivary gland tumors. Conventional imaging techniques have limited usefulness in the quantitative assessment of the parotid glands, making it difficult to differentiate between healthy tissue and tumors, as well as between benign and malignant tumors. Magnetic resonance elastography (MRE) is a non-invasive technique that may potentially overcome these limitations. Nevertheless, due to the size of the parotid gland, increased elastographic resolution is required. This may be achieved by applying shear waves at higher frequencies. However, it also results in stronger attenuation, making the illumination of the parotid challenging. Here, we describe a novel passive driver tailored to the anatomy of the human face, which minimizes the distance shear waves need to travel from the source to the area of interest and thus decreases shear wave attenuation, making high-frequency shear wave MRE feasible.

Design of a Colour Consistent LED Driver Considering Temperature Effect

Design of a Colour Consistent LED Driver Considering Temperature Effect

Gate driver, snubber and circuit design considerations for fast‐switching series‐connected SiC MOSFETs

AbstractSeries connection of Silicon Carbide (SiC) Metal‐Oxide‐Semiconductor Field‐Effect Transistors (MOSFETs) is an interesting solution to design switches for voltages that are not yet commercially available or limited for single‐die devices. However, inherent static and dynamic voltage balancing must be achieved. Voltage imbalance is caused by the device parameters spread, whose impact is pronounced in low‐inductive circuit layouts. This study investigates the optimal design and tuning limits of resistor‐capacitor (RC)‐snubber circuits and non‐adaptive, standard, voltage‐source gate drivers for achieving the best balancing in transient and steady‐state voltage distributions among series‐connected discrete SiC MOSFETs operating at speeds up to . It has been shown that a larger parameter mismatch will lead to uneven switching energy losses and larger voltage imbalances. It was also experimentally shown that increasing the gate resistor to slow down the devices will not always improve balancing when their parameter spread is large. Thus, tuning recommendations for the RC‐snubber circuit and gate driver were developed based on these findings.

Design of powerful high-performance drivers for special-purpose LED lighting systems

This paper presents the results of the study of the parameters and characteristics of the developed high-performance electronic control circuits for special-purpose LED lighting systems based on a two-stage forward converter (driver) with an output power of more than 200 W. Operation of the developed driver in the output power range of 13 to 202 W and the supply voltage range of 160 to 250 V was investigated. The maximum efficiency of the developed power supply system at the voltage of 240 V and the output power of 140 W is 89.9%. For the chosen topology, further voltage increase may increase the efficiency, but lead to accelerated degradation of the driver components. The results of the experimental studies of the developed drivers showed the drivers efficiency in the range of 84 to 90% at a load of 52…202 W with a power factor above 0.97 and a nonlinear current distortion factor less than 23.4% over the entire studied range of supply voltages. The high efficiency of the developed driver in a wide range of output power suggests the possibility of using the driver in lighting systems that provide additional power supply to energy storage systems (batteries), including those ensuring operation in the absence of mains power supply.

39‐1: Invited Paper: An Improved Gate Driver Using Oxide TFTs for Large OLED Displays

In this paper, we present the small area and high reliable gate driver in panels using a‐IGZO TFTs for large OLED displays. The proposed gate driver circuit has a small area structure with multiple output buffers connected to one shift register circuit. To lower the voltage stress of the pull‐down TFTs, which have the highest voltage stress among the TFTs of the gate driver, the initial voltage of those TFTs is set to low and increases according to the threshold voltage shift of TFTs during operation. It could be implemented by sensing the degradation of the TFTs using the programmable DC driving method. With these technologies, we were able to reduce the gate driver design area by 40% and improve the reliability by 30% despite reducing the circuit area. We successfully developed OLED TVs from 42 inches to 97 inches using the proposed gate driver.

The power of personas: Exploring an innovative model for understanding stakeholder perspectives in an oncology learning health network.

Learning health networks (LHNs) improve clinical outcomes by applying core tenets of continuous quality improvements (QI) to reach community-defined outcomes, data-sharing, and empowered interdisciplinary teams including patients and caregivers. LHNs provide an ideal environment for the rapid adoption of evidence-based guidelines and translation of research and best practices at scale. When an LHN is established, it is critical to understand the needs of all stakeholders. To accomplish this, we used ethnographic methods to develop personas of different stakeholders within The Canopy Cancer Collective, the first oncology LHN. We partnered with a firm experienced in qualitative research and human-centered design to conduct interviews with stakeholders of The Canopy Cancer Collective, a newly developed pancreatic cancer LHN. Together with the firm, we developed a personas model approach to represent the wide range of diverse perspectives among the representative stakeholders, which included care team members, patients, and caregivers. Thirty-one stakeholders from all facets of pancreatic cancer care were interviewed, including 20 care team members, 8 patients, and 3 caregivers. Interview transcripts were analyzed to construct 10 personas felt to represent the broad spectrum of stakeholders within The Cancer Canopy Collective. These personas were used as a foundation for the design and development of The Cancer Canopy Cancer Collective key drivers and aims. As LHNs continue to facilitate comprehensive approaches to patient-centered care, interdisciplinary teams who understand each other's needs can improve Network unity and cohesion. We present the first model utilizing personas for LHNs, demonstrating this framework holds significant promise for further study. If validated, such an approach could be used as a dynamic foundation for understanding individual stakeholder needs in similar LHN ecosystems in the future.

Development and Implementation of Algorithms for an Intelligent IGBT Gate Driver Using a Low-Cost Microcontroller

High-power IGBTs are used in power electronic converters in a variety of applications: traction drives, renewable power converters, mining equipment, oil and water pumping, and so on. To control a transistor, a special gate driver board is required. This board converts the logical control signal into the appropriate voltage values necessary to turn the resistor on and off. Gate drivers can perform the protection functions of IGBTs using hardware and algorithmic approaches. Application-specific integrated circuits are often used in driver solutions to implement control and protection. The development of an application-specific integrated circuit is a time-consuming and expensive procedure, which increases the cost of the driver. This paper describes the control and protection algorithms implemented in an intelligent IGBT driver based on a low-cost microcontroller. The use of the microcontroller makes the gate driver design more flexible and allows for the accurate tuning of the protection thresholds. The gate driver protects the IGBT from short-circuiting, overcurrent, and overvoltage, monitors the voltage supply, and controls the switch on and switch off processes in the transistor. The performance of the protection algorithms was tested experimentally using a specialized test bench.

Engineering design and manufacturing of a radio frequency plasma driver without Faraday shield for NBI application

A radio frequency (RF) driven ion source is favorable for high-power and long-pulse neutral beam injection (NBI) system. To reduce the damage caused by the isotropic heat and particle fluxes from the plasma, the traditional RF plasma driver of the NBI ion source introduces a Faraday shield (FS) for protection. However, the simulations and experiments show that the FS seriously affects the RF coupling and around 50 % of the input power deposits on the FS. The water-cooled discharge tubes with a double-layer ceramic structure have been developed to avoid using the FS structure. It's expected to improve the RF power transfer efficiency and to promote the development of high-power and long-pulse RF ion source. To verify the feasibility of the double-layer ceramic structure, the paper has carried out the fluid-thermal-structural coupling analysis and the fracture mechanical analysis on two proposed types: the alumina ceramic brazing structure and the silicon nitride ceramic bonding structure. The sample tests and the prototype manufacturing have been completed. Preliminary tests of the plasma discharge on the prototype of the alumina ceramic brazing structure have been launched. A plasma discharge of 30 kW and 20 s have been achieved.

Gate Driver Design for SiC Power MOSFETs With a Low-Voltage GaN HEMT for Switching Loss Reduction and Gate Protection

Gate Driver Design for SiC Power MOSFETs With a Low-Voltage GaN HEMT for Switching Loss Reduction and Gate Protection

Gate Driver Design for Cryogenically Cooled Power Electronic Converters

Gate Driver Design for Cryogenically Cooled Power Electronic Converters

A wide drive frequency matching method for harmonic suppression and voltage stabilization of ultrasonic motors.

To reduce harmonic components, balance system impedance, and stabilize driving voltage, an additional matching circuit is required for ultrasonic motors (USMs) driver. However, the performance of inductor or capacitor matching can be seriously weakened with changes in driving frequency. Therefore, this paper presents a simple and effective LC matching method against driving frequency adjustment for USMs. First, the driving scheme of the USM is proposed and the electromechanical coupling model is analyzed. Subsequently, the output characteristics of the full-bridge inverter are derived theoretically when the driving frequency deviates from the mechanical resonant frequency. Then, the impedance circular transform method is proposed, which can intuitively analyze the effect of matching parameters on the voltage amplitude. A matching objective function is established that can consider both the voltage stabilization and harmonic suppression. The matching parameters are solved using random weight particle swarm optimization. Simulations and experiments demonstrate that within the operating frequency of the USM, the proposed matching method can effectively prevent overvoltage and suppress harmonic components. Furthermore, compared with the existing resonant matching method, the proposed matching method can realize more stable driving capability at different frequencies. The proposed method could be useful for USMs' variable-frequency driver design.

Design of a Robotic Driver With Adaptive Controllers for Vehicle Speed Tracking Tests

Design of a Robotic Driver With Adaptive Controllers for Vehicle Speed Tracking Tests

Design and Implementation of a Power Semiconductor-Based Switching Mode Laser Diode Driver.

Fiber lasers are commonly used in many industrial applications, such as cutting, welding, marking, and additive manufacturing. In a fiber laser system, the driver of a pumping source using a laser diode (LD) module and its dynamic control capability directly affect the performance of the fiber laser system. The commercial design of pumping source drivers for high-power fiber lasers is mainly based on a linear-type DC power supply, which has two major drawbacks, i.e., lower efficiency and bulk. In this regard, this paper proposes for the first time a new design approach with a programmable switching mode laser diode driver using a power semiconductor device (PSD)-based full-bridge phase-shifted (FB-PS) DC-DC converter for driving a 200 W optical power laser diode module. In this paper, the characteristics of a laser diode module and the system configuration of the proposed laser diode driver are first introduced. Then, a current control scheme using the concept of phase angle shifting to achieve a fast dynamic current tracking feature is explained. The proposed current control technique with a fully digital control scheme is then addressed. Next, dynamic mathematical models of the laser diode driver system and controllers are derived, and the quantitative design detail of the controller is presented. To confirm the correctness of the proposed control scheme, a simulation study on a typical control case is performed in PSIM 9.1 software environment. To verify the effectiveness of the proposed LD driver, a digital signal processor is then used as the control core to construct a hardware prototype implementation for performing experimental tests. Results obtained from simulation and hardware tests show highly satisfactory driving performances in the laser diode's output current command tracking control.

An integrated model for understanding the role of self-service technology attributes and customers’ demographic characteristics in the restaurant service context

ABSTRACT Due to the growth of self-service technology (SST) in the service setting, in this study we propose and test a comprehensive model that captures the relative impacts of SST-related drivers (functionality, enjoyment, security/privacy, assurance, design, convenience, and customization) of customer attitude and behavioral intention in the restaurant setting. We surveyed 312 restaurant customers using SST and analyzed our proposed model using partial least squares structural equation modeling. Our results demonstrate, first, that the factors influencing customer attitudes toward SST are functionality and convenience. Second, customer attitude influences customer intentions to use SST in the future. Third, there are differences among SST attributes on customer behavior across gender, age, and income. There are significant impacts of enjoyment on attitudes among male, young, and high-income customers. This study contributes to the existing hospitality literature by examining the relative roles of various SST attributes as well as the demographic factors in the restaurant service context.