Abstract: A measurement-based method to control and optimize the performance of an airborne vehicle. The stability and control of the vehicle is modified to induce a response in the airborne vehicle as reflected by a plurality of response signals. Excitations signals having multi-term sinusoidal waveforms are generated and applied to control signals controlling one or more control effectors. A time domain response of each of the state variables, response signals, and control signals arising from the application of the excitation inputs to the control signals is then measured. These time domain responses are then transformed into frequency domain models. The effectiveness and vehicle stability and control derivatives may then be identified from the frequency domain models of the state variables, response signals, and control signals.

Abstract: A bias correction system for use in a neutrally-stable aircraft having a control column and a pitch control system is provided. The position of the control column is generally represented by a control column position signal. The bias correction system is for removing control column bias when the control column is in a neutral position. The bias correction system includes a first combining unit for combining the control column position signal and a correction signal, and a switch. The switch includes activated and deactivated states. The switch is set to the deactivated state when the control column is physically displaced from its neutral position. The deactivated state allows the correction signal to remain at its last value, the activated state allows the correction signal to equal approximately the control column position signal.

Abstract: A method and system is disclosed for using inertial sensors in an Inertial Navigation System (INS) to obtain analytic estimates of angle-of-attack (&agr;) and sideslip angle (&agr;). The inertial sensors consist of one or more accelerometers which produce the estimated signals for angle-of-attack (&agr;) and sideslip angle (&bgr;). Three methods are shown for obtaining &agr; and &bgr; estimates from INS information and are programmed into a nonlinear simulation of a relaxed stability aircraft requiring a high level of artificial stability augmentation in its flight control system. Simulation results from the nonlinear simulation for each of the three methods were compared with the results obtained when conventional probes were used to obtain direct measurements of &agr; and &bgr;.

Abstract: An airdata estimation and evaluation system and method, including a stable algorithm for estimating airdata from nonintrusive surface pressure measurements. The airdata estimation and evaluation system is preferably implemented in a flush airdata sensing (FADS) system. The system and method of the present invention take a flow model equation and transform it into a triples formulation equation. The triples formulation equation eliminates the pressure related states from the flow model equation by strategically taking the differences of three surface pressures, known as triples. This triples formulation equation is then used to accurately estimate and compute vital airdata from nonintrusive surface pressure measurements.

Abstract: An autopilot controller, for controlling a vehicle traveling in a fluid medium, designed for controlling the vehicle in any one of pre stall, stall and post stall regions. The autopilot controller provides an approach for one-to-one mapping between a target command which is received and control surface deflections for effecting the command based on vehicle normal force and vehicle moment response characteristics. In one embodiment, the autopilot controller determines linear functions representative of the vehicle dynamic response for the current operating conditions in order to determine a direction of change of fin deflection for effecting the command. In another embodiment, the autopilot controller controls transverse vehicle accelerations by controlling a body pitch moment generated by a control surface.

Abstract: The present invention is directed to a non-normalized aircraft angle-of-attack indicating system. An angle-of-attack vane produces a signal .alpha.' indicative of raw aircraft angle-of-attack. A pitot-static system (68) produces output signals representative of aircraft static pressure and total pressure, P.sub.s and P.sub.t, respectively. The signals .alpha.', P.sub.s and P.sub.t are fed to an air data computer (66) which correspondingly produces an aircraft actual angle-of-attack value .alpha. and a calculated Mach number, M. Configuration sensors (80) produce output signals representative of gear position, g, flap position, f, and speed brake position, sb. The signals .alpha., M, g, f and sb are fed to a display computer (76). The display computer includes a submodule (90) which utilizes a lookup table to determine a value of angle-of-attack stick shaker, .alpha..sub.ss from the values of M, g, f and sb. A second submodule (92) utilizes a lookup table to produce a second angle-of-attack reference value .

Abstract: A process and a device for verifying the consistency of the measurements made by an angle-of-attack probe (2) mounted on an aircraft. The device (1) includes:first system (3) for computing a first coefficient of lift of the aircraft from a measurement from the probe (2) and from data relating to the aircraft;second system (5) for computing a second coefficient of lift from information about the aircraft;system (6) for computing the difference between the first and second coefficients of lift and for deducting therefrom that the measurement is or is not consistent.

Abstract: A method for detecting a bank angle experienced by a motor vehicle (10) is disclosed. Three estimates of the vehicle bank angle, .gamma..sub.a, .gamma..omega. and .gamma..sub..nu. are determined from separate data and are then used to determine an estimate of the bank angle BIAS. The bank angle BIAS is then combined with one of the three bank angle estimates to determine a final bank angle estimate, .gamma..sub.final, to be used to modify the vehicle's yaw control calculations in accordance therewith.

Abstract: A system and method for determining the angular orientation of a body moving in object space. The invention is usable to detect and identify the angular orientation of the body relative to the theoretical plane of gravity and thereby relative to any other theoretical plane between zero and three-hundred sixty degrees therefrom. The invention is operable regardless of whether the body is rotating with an angular velocity, either natural and/or induced. The invention may employ one or more analog and/or digital sensors. The analog sensor may be an accelerometer. The system may be used to provide real-time orientation data to permit the body to be guided or directed towards a desired destination or simply to permit the orientation of the body to be known, controlled or varied as desired.

Abstract: The apparatus of this invention includes a pilot-induced oscillation (PIO) detector, a PIO compensator and a pilot input modifier. The PIO detector is coupled to receive aircraft state signal including the aircraft's pitch, roll and yaw attitudes. The PIO detector is also coupled to receive pilot control signal generated by the aircraft's pilot by manipulation of flight control instruments. Preferably, the PIO detector includes a feature calculator and a discriminator. Based on the aircraft state signal and the pilot control signal, the feature calculator generates at least one feature signal indicative of whether a PIO or non-PIO condition exists in the aircraft. The feature calculator supplies the feature signal to the discriminator, that uses the feature signal to determine whether or not a PIO condition exists.

Abstract: Methods are provided for improving steering stability in a vehicle in which steering stability is a function of tire deflection. In one embodiment, a determination is made whether steering stability has been lost, and if so, the damping rate of all vehicle shock absorbers is increased, thereby reducing tire deflection and improving steering stability. In another embodiment, individual corner control is implemented such that the overall desired yaw torque and the yaw torque produced by an individual tire are determined and the shock absorber damping rate is adjusted accordingly for the respective tire to improve steering stability.

Abstract: In an apparatus for transporting textile laps to a comber, wherein the apparatus includes a bridge structure for traveling movement between a lap storage station and the comber, a trolley movable along the bridge structure, and a lap gripping mechanism suspended from the trolley by an elevating mechanism, sensors are provided for detecting the presence of a lap at the lap storage station and detecting the central supporting tube of the lap for precisely positioning the gripping mechanism at a lowered position at the lap storage station to engage a full replacement lap. A controller is associated with the sensors for controlling subsequent lowering of the gripping mechanism at the comber by the same distance the gripping mechanism was lowered at the storage station to initially receive the replacement lap, thereby to insure that the lap is deposited at the comber safely and gently without damage.