Lateral Commands Research Articles

Preliminary Study of Tactical-Level Interaction for Highly-Automated Vehicles: Its Application to Touchscreen Interface

In automated vehicles, drivers are only required to input high-level control commands. The conventional driver-vehicle interfaces (DVIs) such as steering wheel and pedals that function in operational level may not be utilized in higher levels of automation. A DVI that allows the driver to input tactical-level control commands, .e.g., lane change, by easily understanding a situation, would be potentially required for automated vehicles. We thus propose tactical-level-interaction (TLI) for lateral and longitudinal controlling of highly automated vehicles. In this study, we developed a touchscreen-based DVI that allows the driver to use touch gestures to input tactical control commands. The screen displays an augmented map including the ego vehicle rendered from the top view. The driver can instantly input a set of lateral commands by location-based TLI, e.g., lane changing, by designating a desired location on the map, e.g., lane, by double tapping and swiping. We performed experiments using a simulator to evaluate TLI compared with the operational- (OLI) and strategical-level interaction (SLI). The results show that TLI offers both the flexibility of OLI as well as comfort of SLI, and drivers prefer to use all three interaction methods depending on the driving environment.

Onboard guidance system design for reusable launch vehicles in the terminal area energy management phase

A terminal area energy management (TAEM) guidance system for an unpowered reusable launch vehicle (RLV) is proposed in this paper. The mathematical model representing the RLV gliding motion is provided, followed by a transformation of extracting the required dynamics for reference profile generation. Reference longitudinal profiles are conceived based on the capability of maximum dive and maximum glide that a RLV can perform. The trajectory is obtained by iterating the motion equations at each node of altitude, where the angle of attack and the flight-path angle are regarded as regulating variables. An onboard ground-track predictor is constructed to generate the current range-to-go and lateral commands online. Although the longitudinal profile generation requires pre-processing using the RLV aerodynamics, the ground-track prediction can be executed online. This makes the guidance scheme adaptable to abnormal conditions. Finally, the guidance law is designed to track the reference commands. Numerical simulations demonstrate that the proposed guidance scheme is capable of guiding the RLV to the desired touchdown conditions.

Design of the Scheme Flight Trajectory Command for the Tactical Missile

For the case of the scheme trajectory command design for the tactical missile, the longitudinal and lateral commands and the compound controller of the attitude and height were designed. In the launch segment, four kinds of heading angle commands were presented adopting the arc method and reduction law. In the variable height flight segment, two kinds of height commands were gained by using the parabolic and exponential function. Considering the earth curvature, the formula of the great circle course and distance was gotten applying spherical triangle solution method, and the flight command along the route dot in the lateral plane was obtained. The simulation results show that the designed scheme trajectory commands are feasible and effectively.