David R. Mikesell

Modeling, simulation, and concept design for hybrid-electric medium-size military trucks

A large scale design space exploration can provide valuable insight into vehicle design tradeoffs being considered for the U.S. Army’s FMTV (Family of Medium Tactical Vehicles). Through a grant from TACOM (Tank-automotive and Armaments Command), researchers have generated detailed road, surface, and grade conditions representative of the performance criteria of this medium-sized truck and constructed a virtual powertrain simulator for both conventional and hybrid variants. The simulator incorporates the latest technology among vehicle design options, including scalable ultracapacitor and NiMH battery packs as well as a variety of generator and traction motor configurations. An energy management control strategy has also been developed to provide efficiency and performance. A design space exploration for the family of vehicles involves running a large number of simulations with systematically varied vehicle design parameters, where each variant is paced through several different mission profiles and multiple attributes of performance are measured. The resulting designs are filtered to remove dominated designs, exposing the multi-criterial surface of optimality (Pareto optimal designs), and revealing the design tradeoffs as they impact vehicle performance and economy. The results are not yet definitive because ride and drivability measures were not included, and work is not finished on fine-tuning the modeled dynamics of some powertrain components. However, the work so far completed demonstrates the effectiveness of the approach to design space exploration, and the results to date suggest the powertrain configuration best suited to the FMTV mission.

Portable Automated Driver for Road Vehicle Dynamics Testing

An automated test driver (ATD) has been developed which is capable of executing dynamic test maneuvers with accuracy and repeatability beyond the ability of a human driver. This system enables any production car or light truck to follow a user-defined path or to perform specific steering sequences with excellent repeatability. Combined with an automated brake and throttle controller, capable of matching a desired velocity profile as well as providing specific test inputs with acceleration or other feedback, this system provides a powerful tool to improve vehicle dynamics testing.Copyright

Hardware-in-the-Loop Pneumatic Braking System for Heavy Truck Testing of Advanced Electronic Safety Interventions

The rapid innovation underway with vehicle brake safety systems leads to extensive evaluation and testing by system developers and regulatory agencies. The ability to evaluate complex heavy truck braking systems is potentially more rapid and economical through hardware-in-the-loop (HiL) simulation which employs the actual electronics and vehicle hardware. Though the initial HiL system development is time consuming and expensive, tests conducted on the completed system do not require track time, fuel, vehicle maintenance, or technician labor for driving or truck configuration changes. Truck and trailer configuration and loading as well as test scenarios can be rapidly adjusted within the vehicle dynamics simulation software to evaluate the performance of automated safety interventions (such as ESC) over a wide range of conditions. Hardware-in-the-loop simulation does not obviate the need for all track testing; vehicle models for simulation must be validated against track data for each truck platform. But HiL simulation can supplement and extend track data for tests at higher speeds, low friction surfaces, and alternate vehicle configurations. A HiL pneumatic braking system was developed for this purpose by the National Highway Traffic Safety Administration, with the goal of evaluating performance as it relates to safety. This paper describes the system in detail and includes some sample results of the testing. Language: en

Portable Autonomous Vehicle Controller

Developers of autonomous vehicle control schemes and path planning algorithms typically face a substantial obstacle in implementation and testing. The portable controller proposed here contains the actuators, sensors, and low-level servocontrollers allowing developers to readily implement their lateral and/or longitudinal control algorithms (or other vehicle control-related technique) on any passenger car or light truck with an automatic transmission. Developed originally for vehicle dynamics testing, this system is evaluated on several vehicles with controllers described herein.