Your Selections

Wagner, John R.
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Evaluation of a Robust Haptic Interface for Semi-Autonomous Vehicles

SAE International Journal of Connected and Automated Vehicles

Clemson University, USA-Chengshi Wang, Yue Wang, John R. Wagner
  • Journal Article
  • 12-02-02-0007
Published 2019-05-15 by SAE International in United States
The advent of steer-by-wire technologies has changed the driving paradigm for drivers and vehicle autonomy. Such technologies integrate electric motors to actuate the tire-road plus human-machine interfaces. Steer-by-wire vehicles can benefit from haptic concepts through the provision of tunable force feedback, coupled with nonlinear control, to introduce lane keeping and pathway following technologies that minimize and possibly eliminate driver actions. In this article, two vehicle haptic interfaces, including a robotic grip and a joystick, both of which are accompanied by nonlinear sliding mode control, have been developed and studied on a steer-by-wire platform integrated with a virtual reality driving environment. An operator-in-the-loop evaluation that included 30 human test subjects investigated these haptic steering interfaces over a prescribed series of driving maneuvers through real-time data logging and post-test questionnaires. A conventional steering wheel with the robust sliding mode controller was used for all the driving events for comparison. Subjective and objective results from the tests demonstrate that the driver’s experience can be enhanced by up to 76.3% with a robotic grip steering input when compared to…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Trust-Based Control and Scheduling for UGV Platoon under Cyber Attacks

Clemson University-Fangjian Li, John R. Wagner, Yue Wang
U.S. Army TARDEC-Dariusz Mikulski
Published 2019-04-02 by SAE International in United States
Unmanned ground vehicles (UGVs) may encounter difficulties accommodating environmental uncertainties and system degradations during harsh conditions. However, human experience and onboard intelligence can may help mitigate such cases. Unfortunately, human operators have cognition limits when directly supervising multiple UGVs. Ideally, an automated decision aid can be designed that empowers the human operator to supervise the UGVs. In this paper, we consider a connected UGV platoon under cyber attacks that may disrupt safety and degrade performance. An observer-based resilient control strategy is designed to mitigate the effects of vehicle-to-vehicle (V2V) cyber attacks. In addition, each UGV generates both internal and external evaluations based on the platoons performance metrics. A cloud-based trust-based information management system collects these evaluations to detect abnormal UGV platoon behaviors. To deal with inaccurate information due to a V2C cyber attack, a RoboTrust algorithm is designed to analyze vehicle trustworthiness and eliminate information with low credit. Finally, a human operator scheduling algorithm is proposed when the number of abnormal UGVs exceeds the limit of what human operators can handle concurrently. Representative simulation results…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Automotive Waste Heat Recovery after Engine Shutoff in Parking Lots

SAE International Journal of Advances and Current Practices in Mobility

Clemson University-Zaker Syed, John R. Wagner
  • Journal Article
  • 2019-01-0157
Published 2019-04-02 by SAE International in United States
1The efficiency of internal combustion engines remains a research challenge given the mechanical friction and thermodynamic losses. Although incremental engine design changes continue to emerge, the harvesting of waste heat represents an immediate opportunity to address improved energy utilization. An external mobile thermal recovery system for gasoline and diesel engines is proposed for use in parking lots based on phase change material cartridges. Heat is extracted via a retrofitted conduction plate beneath the engine block after engine shutoff. An autonomous robot attaches the cartridge to the plate and transfers the heat from the block to the Phase Change Material (PCM) and returns later to retrieve the packet. These reusable cartridges are then driven to a Heat Extraction and Recycling Tower (HEART) facility where a heat exchanger harvests the thermal energy stored in the cartridges. A series of mathematical models are created to estimate the recoverable heat from a standard parking lot configuration. A representative case study that considered 500 cars with periodic traffic flow over a period of 16 hours can heat approximately 25 kiloliters…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

An Innovative Electric Motor Cooling System for Hybrid Vehicles - Model and Test

Clemson University-Shervin Shoai Naini, Junkui (Allen) Huang, Richard Miller, John R. Wagner
US Army TARDEC-Denise Rizzo, Katherine Sebeck, Scott Shurin
Published 2019-04-02 by SAE International in United States
Enhanced electric motor performance in transportation vehicles can improve system reliability and durability over rigorous operating cycles. The design of innovative heat rejection strategies in electric motors can minimize cooling power consumption and associated noise generation while offering configuration flexibility. This study investigates an innovative electric motor cooling strategy through bench top thermal testing on an emulated electric motor. The system design includes passive (e.g., heat pipes) cooling as the primary heat rejection pathway with supplemental conventional cooling using a variable speed coolant pump and radiator fan(s). The integrated thermal structure, “cradle”, transfers heat from the motor shell towards an end plate for heat dissipation to the ambient surroundings or transmission to an external thermal bus to remote heat exchanger. A complete lumped parameter numerical modelling was implemented to estimate the thermal behavior of the corresponding electric motor cooling system. Experimental and numerical results compare the temperature, heat flux, and cooling power measurements. For 250VA thermal load applied, the hybrid heat rejection strategy could save up to 33% of the power consumption while the operating…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Design of a Portable Thermoelectric Convective Cooling System for Neighborhood Electric Vehicles and Other Applications

Clemson University-John R. Wagner
Mercer Engineering Research Center-Joshua Finn
Published 2019-04-02 by SAE International in United States
Automotive technology is increasingly reliant on electrically driven accessories, systems, and payloads thanks to the rising popularity of electric and hybrid electric vehicles. Solid state and similar purely electrical solutions such as thermoelectric devices are eminently preferable sources for thermal management in neighborhood electric vehicles (NEVs) and similar short-range automobiles which often do not come stock with a climate control system. Directed convection strategies such as zone cooling using DC electric current are a natural fit for the infinitely scalable thermal control architecture possible with thermoelectrics. One such prototype device, actuated by thermoelectric devices, has been developed to meet a variety of thermal management needs with a versatile, portable system suitable for NEVs, micro cars without air conditioning, or even more specialized cooling needs. This portable hand-held device has been designed, fabricated, and experimentally tested to demonstrate the effectiveness of the concept. The laboratory results demonstrated that the test unit can effectively provide solid state forced convective cooling. The experimental results facilitated the design of an enhanced modular cooling device with output approaching 200 W…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A Hybrid Thermal Bus for Ground Vehicles Featuring Parallel Heat Transfer Pathways

SAE International Journal of Commercial Vehicles

Clemson Unversity-Shervin Shoai Naini, Junkui (Allen) Huang, Richard Miller, John R. Wagner
US Army TARDEC-Denise Rizzo, Katherine Sebeck, Scott Shurin
  • Journal Article
  • 2018-01-1111
Published 2018-04-03 by SAE International in United States
Improved propulsion system cooling remains an important challenge in the transportation industry as heat generating components, embedded in ground vehicles, trend toward higher heat fluxes and power requirements. The further minimization of the thermal management system power consumption necessitates the integration of parallel heat rejection strategies to maintain prescribed temperature limits. When properly designed, the cooling solution will offer lower noise, weight, and total volume while improving system durability, reliability, and power efficiency. This study investigates the integration of high thermal conductivity (HTC) materials, carbon fibers, and heat pipes with conventional liquid cooling to create a hybrid “thermal bus” to move the thermal energy from the heat source(s) to the ambient surroundings. The innovative design can transfer heat between the separated heat source(s) and heat sink(s) without sensitivity to gravity. A case study examines the thermal stability, heat dissipation capabilities, power requirements, and system weights for several driving cycles. Representative numerical results show that the HTC materials and carbon fibers offer moderate cooling while loop heat pipes provide significant improvements for passive cooling.
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Evaluation of Alternative Steering Devices with Adjustable Haptic Feedback for Semi-Autonomous and Autonomous Vehicles

Clemson University-Chengshi Wang, Yue Wang, John R. Wagner
Published 2018-04-03 by SAE International in United States
Emerging autonomous driving technologies, with emergency navigating capabilities, necessitates innovative vehicle steering methods for operators during unanticipated scenarios. A reconfigurable “plug and play” steering system paradigm enables lateral control from any seating position in the vehicle’s interior. When required, drivers may access a stowed steering input device, establish communications with the vehicle steering subsystem, and provide direct wheel commands. Accordingly, the provision of haptic steering cues and lane keeping assistance to navigate roadways will be helpful. In this study, various steering devices have been investigated which offer reconfigurability and haptic feedback to create a flexible driving environment. A joystick and a robotic arm that offer multiple degrees of freedom were compared to a conventional steering wheel. To evaluate the concept, human test subjects interacted with the experimental system featuring a driving simulator with target hardware, and completed post-test questionnaires. Based on the data collected, drivers’ lane keeping performance was superior using a haptic robotic arm with haptic feedback to the joystick and steering wheel with an improvement of up to 70.18% during extreme maneuvers. Haptic…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

An Integrated Cooling System for Hybrid Electric Vehicle Motors: Design and Simulation

SAE International Journal of Commercial Vehicles

Clemson University-Junkui (Allen) Huang, Shervin Shoai Naini, Richard miller, John R. Wagner
US Army TARDEC-Denise Rizzo, Katherine Sebeck, Scott Shurin
  • Journal Article
  • 2018-01-1108
Published 2018-04-03 by SAE International in United States
Hybrid electric vehicles offer the advantages of reduced emissions and greater travel range in comparison to conventional and electric ground vehicles. Regardless of propulsion strategy, efficient cooling of electric motors remains an open challenge due to the operating cycles and ambient conditions. The onboard thermal management system must remove the generated heat so that the motors and other vehicle components operate within their designed temperature ranges. In this article, an integrated thermal structure, or cradle, is designed to efficiently transfer heat within the motor housing to the end plates for transmission to an external heat exchanger. A radial array of heat pipes function as an efficient thermal connector between the motor and heat connector, or thermal bus, depending on the configuration. Cooling performance has been evaluated for various driving cycles. Numerical results show that 1.3 kW of peak heat wattage can be accommodated with free convection while 3.2 kW is obtained by adding forced convection using 13.7 W of electric power. The internal motor temperature is maintained within the prescribed limits of 75°C and 55°C…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Optimization of a Military Ground Vehicle Engine Cooling System Heat Exchanger - Modeling and Size Scaling

Xinran Tao
Clemson University-John R. Wagner
Published 2017-03-28 by SAE International in United States
Heat rejection in ground vehicle propulsion systems remains a challenge given variations in powertrain configurations, driving cycles, and ambient conditions as well as space constraints and available power budgets. An optimization strategy is proposed for engine radiator geometry size scaling to minimize the cooling system power consumption while satisfying both the heat removal rate requirement and the radiator dimension size limitation. A finite difference method (FDM) based on a heat exchanger model is introduced and utilized in the optimization design. The optimization technique searches for the best radiator core dimension solution over the design space, subject to different constraints. To validate the proposed heat exchanger model and optimization algorithm, a heavy duty military truck engine cooling system is investigated. For a convoy escort driving cycle, numerical results demonstrate that by increasing the prototype radiator frontal area, the cooling system energy cost can be significantly reduced. The proposed radiator size scaling algorithm offered a methodology of evaluating the tradeoff between physical dimension, heat generation and power. It is a powerful tool that allows optimal deciding the…
This content contains downloadable datasets
Annotation ability available
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Control of a Thermoelectric Cooling System for Vehicle Components and Payloads - Theory and Test

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Clemson University-John R. Wagner
Mercer Engineering Research Center-Joshua W. Finn
  • Journal Article
  • 2017-01-0126
Published 2017-03-28 by SAE International in United States
Hybrid vehicle embedded systems and payloads require progressively more accurate and versatile thermal control mechanisms and strategies capable of withstanding harsh environments and increasing power density. The division of the cargo and passenger compartments into convective thermal zones which are independently managed can lead to a manageable temperature control problem. This study investigates the performance of a Peltier-effect thermoelectric zone cooling system to regulate the temperature of target objects (e.g., electronic controllers, auxiliary computer equipment, etc) within ground vehicles. Multiple thermoelectric cooling modules (TEC) are integrated with convective cooling fans to provide chilled air for convective heat transfer from a robust, compact, and solid state device. A series of control strategies have been designed and evaluated to track a prescribed time-varying temperature profile while minimizing power consumption. The zone cooling device was tested within an enclosed cabin to provide localized convective zone cooling to a representative heat producing component. Mathematical models for the TEC’s and overall system were developed and validated using these test results. The experimental results demonstrated that an amplitude modulated output from…
This content contains downloadable datasets
Annotation ability available