Launch and space vehicle control studies. Volume 2 - Space vehicle control studies Final report
Control and stabilization of space vehicles
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Prediction of forces and moments for flight vehicle control effectors. Part 1: Validation of methods for predicting hypersonic vehicle controls forces and moments
Many types of hypersonic aircraft configurations are currently being studied for feasibility of future development. Since the control of the hypersonic configurations throughout the speed range has a major impact on acceptable designs, it must be considered in the conceptual design stage. The ability of the aerodynamic analysis methods contained in an industry standard conceptual design system, APAS II, to estimate the forces and moments generated through control surface deflections from low subsonic to high hypersonic speeds is considered. Predicted control forces and moments generated by various control effectors are compared with previously published wind tunnel and flight test data for three configurations: the North American X-15, the Space Shuttle Orbiter, and a hypersonic research airplane concept. Qualitative summaries of the results are given for each longitudinal force and moment and each control derivative in the various speed ranges. Results show that all predictions of longitudinal stability and control derivatives are acceptable for use at the conceptual design stage. Results for most lateral/directional control derivatives are acceptable for conceptual design purposes; however, predictions at supersonic Mach numbers for the change in yawing moment due to aileron deflection and the change in rolling moment due to rudder deflection are found to be unacceptable. Including shielding effects in the analysis is shown to have little effect on lift and pitching moment predictions while improving drag predictions.
Maughmer, Mark D.↗
Assessment of Remote Pilot Maneuver Taskload under Multi-Vehicle Control
Multi-vehicle control schemes where a number of remote pilots (m) supervise a number of uncrewed vehicles (m:N) are desired to enable scalability of operations, such as air cargo delivery, in the face of pilot shortage and other constraints. We use queuing models derived from historical track data to assess the increased task load on a remote pilot due to maneuvering demands as the number of supervised vehicles increase. We quantify metrics such as the probability that the inter-maneuver time and inter-communication time.
Multi-Vehicle Control↗
Launch vehicle control systems research
Launch vehicle control system research facility
RESEARCH FACILITY↗
High speed flight vehicle control Patent
Supersonic or hypersonic vehicle control system comprising elevons with hinge line sweep and free of adverse aerodynamic cross coupling
Rainey, R. W.↗
Launch Vehicle Control Center Architectures
Launch vehicles within the international community vary greatly in their configuration and processing. Each launch site has a unique processing flow based on the specific launch vehicle configuration. Launch and flight operations are managed through a set of control centers associated with each launch site. Each launch site has a control center for launch operations; however flight operations support varies from being co-located with the launch site to being shared with the space vehicle control center. There is also a nuance of some having an engineering support center which may be co-located with either the launch or flight control center, or in a separate geographical location altogether. A survey of control center architectures is presented for various launch vehicles including the NASA Space Launch System (SLS), United Launch Alliance (ULA) Atlas V and Delta IV, and the European Space Agency (ESA) Ariane 5. Each of these control center architectures shares some similarities in basic structure while differences in functional distribution also exist. The driving functions which lead to these factors are considered and a model of control center architectures is proposed which supports these commonalities and variations.
Watson, Michael D.↗
Stochastic Guidance of Buoyancy Controlled Vehicles under Ice Shelves using Ocean Currents
We propose a novel technique for guidance ofbuoyancy-controlled vehicles in uncertain under-ice ocean flows.In-situ melt rate measurements collected at the grounding zoneof Antarctic ice shelves, where the ice shelf meets the underlyingbedrock, are essential to constrain models of future sea levelrise. Buoyancy-controlled vehicles, which control their verticalposition in the water column but have no means of horizontalpropulsion, offer an affordable and reliable platform for suchin-situ data collection. However, reaching the grounding zonerequires vehicles to traverse tens of kilometers under the iceshelf, with approximate position knowledge and no meansof communication, in highly variable and uncertain oceancurrents. To address this challenge, we propose a partiallyobservable MDP approach that exploits model-based knowledgeof the under-ice currents and, critically, of their uncertainty,to synthesize effective guidance policies. The approach usesapproximate dynamic programming to model uncertainty inthe currents, and QMDP to address localization uncertainty.Numerical experiments show that the policy can deliver upto 88.8% of underwater vehicles to the grounding zone – a33% improvement compared to state-of-the-art guidance techniques, and a 262% improvement over uncontrolled drifters.Collectively, these results show that model-based under-iceguidance is a highly promising technique for exploration ofunder-ice cavities, and has the potential to enable cost-effectiveand scalable access to these challenging and rarely observed environments.
Clark, Evan B.↗
Vehicle Controller
UNISTICK is an airplane-like joystick being developed by Johnson Engineering under NASA and VA sponsorship. It allows a driver to control a vehicle with one hand, and is based upon technology developed for the Apollo Lunar Landings of the 1970's. It allows severely handicapped drivers to operate an automobile or van easily. The system is expected to be in production by March 1986.
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Ground vehicle control at NIST: From teleoperation to autonomy
NIST is applying their Real-time Control System (RCS) methodology for control of ground vehicles for both the U.S. Army Researh Lab, as part of the DOD's Unmanned Ground Vehicles program, and for the Department of Transportation's Intelligent Vehicle/Highway Systems (IVHS) program. The actuated vehicle, a military HMMWV, has motors for steering, brake, throttle, etc. and sensors for the dashboard gauges. For military operations, the vehicle has two modes of operation: a teleoperation mode--where an operator remotely controls the vehicle over an RF communications network; and a semi-autonomous mode called retro-traverse--where the control system uses an inertial navigation system to steer the vehicle along a prerecorded path. For the IVHS work, intelligent vision processing elements replace the human teleoperator to achieve autonomous, visually guided road following.
Murphy, Karl N.↗
The automation of remote vehicle control
The automation of remote vehicles is becoming necessary to overcome the requirement of having man present as a controller. By removing man, remote vehicles can be operated in areas where the environment is too hostile for man, his reaction times are too slow, time delays are too long, and where his presence is too costly, or where system performance can be improved. This paper addresses the development of automated remote vehicle control for nonspace and space tasks from warehouse vehicles to proposed Mars rovers. The state-of-the-art and the availability of new technology for implementing automated control are reviewed and the major problem areas are outlined. The control strategies are divided into those where the path is planned in advance or constrained, or where the system is a teleoperator, or where automation or robotics have been introduced.
Paine, G.↗
Simplified Vehicle Control Concept for a Lift Plus Cruise eVTOL Vehicle
Electric Vertical Takeoff and Landing (eVTOL) vehicles have the potential to enable cost effective Urban Air Mobility (UAM) applications. These concepts may also pose several challenging handling and control problems, which must be addressed prior to safe and reliable urban operations. This paper investigates a simplified vehicle control concept that is designed to address some of these challenges for a conceptual Lift Plus Cruise vehicle designed by NASA’s Revolutionary Vertical Lift Technology (RVLT) project. The command and control architecture for this concept is presented along with preliminary findings. Initial results explore the vehicle performance in an approach to hover transition scenario, designed to explore the challenge of dissipating energy across all flight regimes. Operational concepts with varying aggressiveness are evaluated through changing glideslope and deceleration rates. Preliminary results show that the simplified control concept is effective over these operational conditions, with control strategies and envelope protection limits able to maintain control though aggressive operations despite saturation at steeper slopes with higher deceleration rates. Final results will show piloted simulation evaluations in the the Aerospace Cognitive Engineering Lab – Rapid Automation Test Environment (ACEL-RATE) laboratory at NASA Ames Research Center. The planned tests will build on these operations with additional test cases exploring variations in wind conditions as well as transition-to-hover automation strategies and display information.
simplified vehicle control↗
Simplified Vehicle Control Concept for a Lift Plus Cruise eVTOL Vehicle
Electric Vertical Takeoff and Landing (eVTOL) vehicles have the potential to enable cost effective Urban Air Mobility (UAM) applications. These concepts may also pose several challenging handling and control problems, which must be addressed prior to safe and efficient urban operations. This paper investigates a simplified vehicle control concept that is designed to address some of these challenges for a conceptual Lift Plus Cruise vehicle. This concept also includes several variations of a transition-to-hover function, designed to assist pilots in capturing and maintaining a stabilized hover prior to landing. The different simplified control architectures for this concept are presented along with preliminary findings. Preliminary results show that the simplified control concept can be effective in assisting pilots to achieve safe and reliable hover landings, and that transition-to-hover functions have the potential of reducing workload while increasing accuracy. A follow on evaluation will be performed in the Vertical Motion Simulator (VMS) at NASA Ames Research Center. The planned tests will focus on more operationally representative scenarios, while building upon these operations with additional test cases exploring variations in glidepath angles and wind conditions.
simplified vehicle control↗
Simple control-theoretic models of human steering activity in visually guided vehicle control
A simple control theoretic model of human steering or control activity in the lateral-directional control of vehicles such as automobiles and rotorcraft is discussed. The term 'control theoretic' is used to emphasize the fact that the model is derived from a consideration of well-known control system design principles as opposed to psychological theories regarding egomotion, etc. The model is employed to emphasize the 'closed-loop' nature of tasks involving the visually guided control of vehicles upon, or in close proximity to, the earth and to hypothesize how changes in vehicle dynamics can significantly alter the nature of the visual cues which a human might use in such tasks.
Hess, Ronald A.↗
Adaptive functions of man in vehicle control systems.
Adaptive functions of man in vehicle control systems
OPERATOR PERFORMANCE↗
Effects of structural flexibility on launch vehicle control systems
Structural flexibility effects on launch vehicle control systems and design criteria
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Hypersonic vehicle control law development using H(infinity) and micron-synthesis
Hypersonic vehicle control law development using H(infinity) and mu-synthesis is discussed. Airbreathing SSTO vehicles has a mutli-faceted mission that includes orbital operations, as well as re-entry and descent culminating in horizontal landing. However, the most challenging part of the operations is the ascent to orbit. The airbreathing propulsion requires lengthy atmospheric flight that may last as long as 30 minutes and take the vehicle half way around the globe. The vehicles's ascent is characterized by tight payload to orbit margins which translate into minimum fuel orbit as the performance criteria. Issues discussed include: SSTO airbreathing vehicle issues; control system performance requirements; robust control law framework; H(infinity) controller frequency analysis; and mu controller frequency analysis.
Gregory, Irene M.↗
Entry Vehicle Control System Design for the Mars Smart Lander
The NASA Langley Research Center, in cooperation with the Jet Propulsion Laboratory, participated in a preliminary design study of the Entry, Descent and Landing phase for the Mars Smart Lander Project. This concept utilizes advances in Guidance, Navigation and Control technology to significantly reduce uncertainty in the vehicle landed location on the Mars surface. A candidate entry vehicle controller based on the Reaction Control System controller for the Apollo Lunar Excursion Module digital autopilot is proposed for use in the entry vehicle attitude control. A slight modification to the phase plane controller is used to reduce jet-firing chattering while maintaining good control response for the Martian entry probe application. The controller performance is demonstrated in a six-degree-of-freedom simulation with representative aerodynamics.
Calhoun, Philip C.↗
Reusable Launch Vehicle Control In Multiple Time Scale Sliding Modes
A reusable launch vehicle control problem during ascent is addressed via multiple-time scaled continuous sliding mode control. The proposed sliding mode controller utilizes a two-loop structure and provides robust, de-coupled tracking of both orientation angle command profiles and angular rate command profiles in the presence of bounded external disturbances and plant uncertainties. Sliding mode control causes the angular rate and orientation angle tracking error dynamics to be constrained to linear, de-coupled, homogeneous, and vector valued differential equations with desired eigenvalues placement. Overall stability of a two-loop control system is addressed. An optimal control allocation algorithm is designed that allocates torque commands into end-effector deflection commands, which are executed by the actuators. The dual-time scale sliding mode controller was designed for the X-33 technology demonstration sub-orbital launch vehicle in the launch mode. Simulation results show that the designed controller provides robust, accurate, de-coupled tracking of the orientation angle command profiles in presence of external disturbances and vehicle inertia uncertainties. This is a significant advancement in performance over that achieved with linear, gain scheduled control systems currently being used for launch vehicles.
Shtessel, Yuri↗