Human transfer functions for multi-axis and multi-loop problems
Pilot response to multiaxis and multiloop problems by transfer function analysis - human information processing capacity
FLIGHT CONTROL↗
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Human transfer functions in multi-axis and multi-loop control systems
Human transfer functions in multiaxis and multiloop control systems
CLOSED LOOP SYSTEM↗
Human transfer functions for multi-axis and multiloop problems.
Human transfer function for pilot response for multiaxis and multiloop problems
HUMAN REACTION↗
A decision and control multi-axis pilot model based on an urgency for action concept
An all digital multiple axis, multiple input, multiple output pilot model flies five different tasks in aircraft of different classes while encountering turbulence represented by the Dryden spectral model. Six degree of freedom linearized aircraft equations of motion are used together with a generalized stability augmentation system. The pilot model consists of two parts: (1) a decision maker, and (2) a control action implementer. This decision maker selects the critical variable and predicts the error at action implementation. The control action implementer decides the magnitude of control to be applied and applies it. This system has been successfully compared with hybrid/analog man in the loop simulations of the F-5, A-7, T-33, and 707 aircraft, thus validating the all digital simulation and the decision and control pilot model.
Pollard, J. J.↗
An approach to the multi-axis problem in manual control
The multiaxis control problem is addressed within the context of the optimal pilot model. The problem is developed to provide efficient adaptation of the optimal pilot model to complex aircraft systems and real world, multiaxis tasks. This is accomplished by establishing separability of the longitudinal and lateral control problems subject to the constraints of multiaxis attention and control allocation. Control solution adaptation to the constrained single axis attention allocations is provided by an optimal control frequency response algorithm. An algorithm is developed to solve the multiaxis control problem. The algorithm is then applied to an attitude hold task for a bare airframe fighter aircraft case with interesting multiaxis properties.
Harrington, W. W.↗
Multi-axis hand controller for the shuttle remote manipulator system
The Shuttle Remote Manipulator System, has a articulated arm of 50 ft. length with six motor-driven joints. The basic purpose is to establish physical contact with various space hardware items and maneuver these to the desired position and attitude with respect to the Orbiter, nulling out relative velocities and stabilizing the free-body system by managing residual energies. The normal operating mode is resolved-motion end-point rate control by man-in-loop command. The translational freedoms are defined so that the End Effector (EEFTR) of the arm will move in planes parallel to the principal translational planes of the Orbiter, at a rate commanded by the displacement of the Translation Hand Controller in the corresponding freedom and direction. The rotational freedoms are rate-controlled by the Rotation Hand Controller about pivot axes parallel to Orbiter roll, pitch and yaw, originating at the EEFTR reference point.
Lippay, A. L.↗
Multi-axis manual controllers: A state-of-the-art report
A literature search was carried out to examine the feasibility of a six degree of freedom hand controller. Factors addressed included related areas, approaches to manual control, applications of manual controllers, and selected studies of the human neuromuscular system. Results are presented.
Lippay, A.↗
Strapdown system performance optimization test evaluations (SPOT), volume 1
A three axis inertial system was packaged in an Apollo gimbal fixture for fine grain evaluation of strapdown system performance in dynamic environments. These evaluations have provided information to assess the effectiveness of real-time compensation techniques and to study system performance tradeoffs to factors such as quantization and iteration rate. The strapdown performance and tradeoff studies conducted include: (1) Compensation models and techniques for the inertial instrument first-order error terms were developed and compensation effectivity was demonstrated in four basic environments; single and multi-axis slew, and single and multi-axis oscillatory. (2) The theoretical coning bandwidth for the first-order quaternion algorithm expansion was verified. (3) Gyro loop quantization was identified to affect proportionally the system attitude uncertainty. (4) Land navigation evaluations identified the requirement for accurate initialization alignment in order to pursue fine grain navigation evaluations.
Blaha, R. J.↗
The analysis of the pilot's cognitive and decision processes
Articles are presented on pilot performance in zero-visibility precision approach, failure detection by pilots during automatic landing, experiments in pilot decision-making during simulated low visibility approaches, a multinomial maximum likelihood program, and a random search algorithm for laboratory computers. Other topics discussed include detection of system failures in multi-axis tasks and changes in pilot workload during an instrument landing.
Curry, R. E.↗
A kinesthetic-tactual display concept for helicopter-pilot workload reduction
A kinesthetic-tactual (K-T) display concept is now under research and development (R & D) at the Ohio State University. It appears to offer considerable promise for useful application in helicopters by conveying control information via the sense of touch. This is a review of the overall R & D program including the original K-T display design, initial studies in automobile and fixed-wing vehicles, and feasibility experiments in a helicopter simulator. In addition to investigations of control and potential workload reduction, present efforts are directed toward establishing optimal design requirements for K-T helicopter displays. Potential applications, modes of usage, and the kinds of information that may be displayed in helicopter applications are discussed along with a brief forecast of future R & D. A brief description of the latest multi-axis laboratory prototype K-T display is also provided.
Gilson, R. D.↗
Some modern control techniques for human operator modeling and identification
Some recent results in quantitative modeling of the human operator are reviewed as well as a method for processing his input-output data. Modern control techniques are applied to the pilot operating in a dynamic compensatory tracking task. Trained pilots are known to behave in an optimal manner under fully stressed conditions. This has led to the development of an optimal control model of the human operator which takes his limitations into account. A rationale for determining the appropriate cost functions is determined. Experimental results indicate that the model can closely predict pilot performance in one- or two-axis tracking tasks. The model predicts pilot remnant (noise), error scores, and frequency response in both single-axis and multi-axis tracking tasks.
Shirley, R. S.↗
Application of a ground based minicomputer system for real time, closed loop control of remotely piloted aircraft models used in stall/spin research
The paper describes a minicomputer-based, real-time closed loop remote control system at NASA Langley outdoor facility which is used to determine the stall/departure/spin characteristics of high-performance aircraft. The experiments are conducted with 15% dynamically scaled, unpowered models that are dropped from 3000 m and ground controlled. The effects of time delays and sampling rates on the stability of the control system and the selection of digital algorithms to meet frequency response and real time constraints are examined. Also described is the implementation of the modular software for the flexible programming of multi-axis control laws.
Montoya, R. J.↗
Acceptance and control of aircraft interior noise and vibration
Ride quality criteria for noise, vibration, and their combination in the helicopter cabin environment are discussed. Results are presented of laboratory and field studies of passenger responses to interior noise and vibration during the performance of a listening task and during reverie, as well as to the interaction of noise with multi-frequency and multi-axis vibration. A study of means for reducing helicopter interior noise based on analytical, experimental and flight studies of the near-field noise source characteristics of the aircraft, the transmission of noise through aircraft structures and the attenuation of noise by various noise control treatments is then presented which has resulted in a reduction of 3 dB in helicopter cabin noise. Finally, a model under development to evaluate passenger acceptance of a helicopter noise and vibration environment is indicated which incorporates the observed noise and vibration effects on comfort and is expected to provide insights for more effective noise and vibration control.
Stephens, D. G.↗
Simulation of Heavy Lift Airship dynamics over large ranges of incidence and speed
A nonlinear, multibody, six-degrees-of-freedom digital simulation has been developed to study generic Heavy Lift Airship (HLA) dynamics and control. The basic aerodynamic functions developed to model the hull, tail, and rotor loads continuously over all incidence ranges are reviewed and applied to a Quadrotor HLA with a low fineness ratio hull and a small vee-tail. Trim calculations for a test vehicle suggest control power deficiencies in crosswind stationkeeping for the unloaded vehicle. Gust responses show the importance of correctly calculating loads due to accelerated relative motion of air and hull. Numerically linearized dynamics for the test vehicle show the existence of a divergent yaw mode, and an oscillatory pitch mode whose stability characteristics are sensitive to flight speed. A considerable improvement in the vehicle's stability and response results from a simple multi-axis closed-loop control system operating on the rotors and propeller blades.
Tischler, M. B.↗
Application of Nonlinear Systems Inverses to Automatic Flight Control Design: System Concepts and Flight Evaluations
A practical method for the design of automatic flight control systems for aircraft with complex characteristics and operational requirements, such as the powered lift STOL and V/STOL configurations, is presented. The method is effective for a large class of dynamic systems requiring multi-axis control which have highly coupled nonlinearities, redundant controls, and complex multidimensional operational envelopes. It exploits the concept of inverse dynamic systems, and an algorithm for the construction of inverse is given. A hierarchic structure for the total control logic with inverses is presented. The method is illustrated with an application to the Augmentor Wing Jet STOL Research Aircraft equipped with a digital flight control system. Results of flight evaluation of the control concept on this aircraft are presented.
Meyer, G.↗
Automated inspection and precision grinding of spiral bevel gears
The results are presented of a four phase MM&T program to define, develop, and evaluate an improved inspection system for spiral bevel gears. The improved method utilizes a multi-axis coordinate measuring machine which maps the working flank of the tooth and compares it to nominal reference values stored in the machine's computer. A unique feature of the system is that corrective grinding machine settings can be automatically calculated and printed out when necessary to correct an errant tooth profile. This new method eliminates most of the subjective decision making involved in the present method, which compares contact patterns obtained when the gear set is run under light load in a rolling test machine. It produces a higher quality gear with significant inspection time and cost savings.
Frint, Harold↗
The role of modeling and flight testing in rotorcraft parameter identification
The importance of recognizing that each lower-order model used for rotorcraft parameter identification has a limited range of applicability is illustrated in some detail. Examples are given to illustrate the use of conditioning the test input signals and the potential of using multi-axis test inputs to enhance the parameter identifiability. The paper discusses the benefits and limitations of using frequency sweeps as flight-test input signals for identification of frequency response for rotorcraft and for the subsequent fitting of parametric transfer-function models. This paper demonstrates the major role played by analytical modeling and the understanding of the physics involved in the rotorcraft flight dynamics, particularly understanding the limit of lower-order models, in achieving successful rotorcraft parameter identification.
Chen, R. T. N.↗
Model-based analysis of control/display interaction in the hover task
The effect of Control/Display interaction in the hover task is analyzed using an optimal control approach to modeling pilot control behavior. The control/display configurations considered are those previously evaluated in a flight research program. The experimental data-base is reviewed and the procedure for modeling the task and the displayed information is presented in detail. All model-based results, time-domain as well as frequency-domain, are found to correlate extremely well with the subjective pilot ratings and comments. Time-domain measures consist of root mean-square errors and control inputs, attention allocation to displayed quantities, and magnitudes of task objective function. Frequency-domain measures include bandwidth, stability margins, and pilot phase compensation. Results are also shown to agree with previous findings on task interference in multi-axis tasks.
Schmidt, David K.↗