This paper describes the work being performed under the RDECOM Power and Energy (P&E) program (formerly the Combat Hybrid Power System (CHPS) program) developing hybrid power system models and integrating them into larger simulations, such as OneSAF, that can be used to find duty cycles to feed designers of hybrid power systems. This paper also describes efforts underway to link the TARDEC P&E System Integration Lab (SIL) in San Jose CA to the TARDEC Ground Vehicle Simulation Lab (GVSL) in Warren, MI. This linkage is being performed to provide a methodology for generating detailed driver profiles for use in the development of vignettes and mission profiles for system design excursions.
The unmanned ground compat vehicle (UGCV) design evolved by the SAIC team on the DARPA UGCV Program is summarized in this paper. This UGCV design provides exceptional performance against all of the program metrics and incorporates key attributes essential for high performance robotic combat vehicles. This performance includes protection against 7.62 mm threats, C130 and CH47 transportability, and the ability to accept several relevant weapons payloads, as well as advanced sensors and perception algorithms evolving from the PerceptOR program. The UGCV design incorporates a combination of technologies and design features, carefully selected through detailed trade studies, which provide optimum performance against mobility, payload, and endurance goals without sacrificing transportability, survivability, or life cycle cost. The design was optimized to maximize performance against all Category I metrics. In each case, the performance of this design was validated with detailed simulations, indicating that the vehicle exceeded the Category I metrics. Mobility metrics were analyzed using high fidelity VisualNastran vehicle models, which incorporate the suspension control algorithms and controller cycle times. DADS/Easy 5 3-D models and ADAMS simulations were also used to validate vehicle dynamics and control algorithms during obstacle negotiation.
The low gain nature of HF overtone chemical lasers has heretofore limited the devices to low magnifications on the order of 1.5. In this paper analyses are presented that show a phase step mirror resonator can enhance modal feedback in these devices such that operation at magnifications of at least 3 is possible. The mechanism for this feedback enhancement is destructive interference of the output wave causing confinement of the beam around the resonator axis. It is shown that the radius of the phase step for optimum performance is directly related to the resonator geometry. It is also seen that the phase step technique increases sensitivity of the resonator to misalignments. The analyses include both two and three-dimensional physical optics calculations complete with rotational non-equilibrium chemical laser gain.
In this study geometric and physical optics analyses were used to examine an HF overtone/UR90 design (OTR90). The geometric analyses were primarily used to calculate the physical optics parameters and to understand the misalignment sensitivities of the resonator. The physical optics calculations then provided information regarding output power, phase and intensity distributions, and mode control. The physical parameters used in the optical analyses were based on a rectangular resonator designed around the NACL, two-bank gain generator and facility; a likely candidate for a near-term HF overtone experiment. Also, the gain model was anchored to the small-signal gain (SSG) and spectrum of this device. These analyses show that indeed high power within a good mode can be extracted using this resonator and that the impact of mirror misalignment is greatly reduced.
A variety of resonator designs that may be scalable to large high-power HF overtone lasers are discussed. Multipass resonators with multiple turning mirrors and with common turning mirrors are included in the discussion. Geometric optics are utilized in analyzing these concepts. Emphasis is placed on gain saturation, amplified-spontaneous-emission and parasitic control by gain segmentation, alignment tolerances, and diffractive beam spillage. It is concluded that for moderate powers, the multipass concept with separate turning mirrors is preferable, while for higher powers, a concept with common turning mirrors may be chosen.