Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
  • G01B7/30—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring angles or tapers; for testing the alignment of axes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C9/00—Adjustable control surfaces or members, e.g. rudders

Definitions

• the present invention relates to a method and appara ⁇ tus for measuring the angle between devices relative to a reference plane and, more particularly, to an electrical system for measuring the angle between inboard or outboard flaps relative to a wing reference plane of an aircraft.
• an electrical system for measuring the angle between inboard or outboard flaps relative to a wing reference plane of an aircraft.
• bulky mechanical protractors or optical sighting techniques have been utilized for measuring angles relative to a reference plane.
• the patent literature includes U. S. Patent No. 3,478,569 which relates to an electronic method for rigging aircraft control surfaces.
• the present flap position measuring system utilizes a plurality of servo inclinometers.
• servo inclinometers employ a force balance principle, allowing a much higher degree of accuracy to be achieved.
• a high degree of accuracy is particularly important in an aircraft environment where newer fuel efficient aircraft do not permit any discrepancy in the alignment of a control surface such as the flaps which would con ⁇ tribute to increased drag.
• the flap position measuring system in accordance with a preferred embodiment of the present invention results in an accuracy of + 3 minutes of arc over a range of + 20 , an overall accuracy deemed an order of magnitude better than that shown in U. S. Patent 3,478,569, which accuracy is achievable through utilization in the present system embodiment of servo inclinometers. Accordingly, it is an object of the present invention to provide means, including a plurality of servo inclinom ⁇ eters, for measuring angles relative to a reference plane. .
• Figure 1 is a side elevational view taken in section of a wing section-of an aircraft showing prior art devis- tion of mechanical protractor for flap position measure ⁇ ment;
• Figure 2 is a bottom plan view of an aircraft showing servo inclinometer arrangement relative to the wing reference plane in the present preferred system embodiment
• Figure 3 is a wing section view taken along the line 3 - 3 of the aircraft shown in Figure 2;
• Figure 4 is a block diagram electrical circuit system schematic of the present measuring system
• Figures 5A, 5B, and 5C show a complete electrical cir- cuit schematic of the measuring system shown in Figure 4.
• FIG 1 a prior art flap position measuring method is shown wherein the flap portion 12 of wing 14 includes a mechanical protractor 16 for making flap angle measurements between flap 12 position shown and the flap position shown in dotted line rendition at 18.
• a prior art flap measuring technique as shown in Figure 1 which includes the use of bulky mechanical protractors and results in inaccurate measurements, cannot be tolerated in the angle measurements required in the new fuel effici ⁇ ent aircraft.
• the present measuring system shown in block diagram in Figure 4 utilizes a plurality of remotely mounted transducers 20, 22, and 24 of the servo inclinometer type and includes reference transducer 20 disposed in the wing 14 reference plane with respect to which all other pitch axis angles can be measured.
• Reference transducer 20 may more parti ⁇ cularly (not shown) be mounted on a holding fixture attached to one of the fuel -cell inspection openings of wing 14.
• Inboard flap transducer 22 and outboard flap transducer 24 are mounted on the corresponding trailing " edges of the respective inboard 12 and outboard 13 flaps, as shown in Figure 2.
• the relative angle ⁇ the angle of inclination denoted by numeral 26 in Figure 3 is read out in utilization means comprising a display device 100, shown specifically in the full circuit diagram embodiment portion of the schematic at Figure 5C.
• the display device showing the angle of inclination ⁇ is also shown in the block diagram of Figure 4 of the present preferred system embodiment at 100.
• each of the servo inclinometers 20, 22 and 24 are coupled through respective twisted shielded cables 40, 42 and 44 to signal processing circuits downstream, including differential input amplifiers 46, 48, and 50 which reduce unwanted noise pickup.
• the first stage differential amplifiers 46, 48, and 50 are utilized in the signal processing of the present system to perform zero offs.et and scale factor adjustments for each of respective servo inclinometers 20, 22, and 24.
• Reference servo inclinometer 20, inboard servo inclinometer 22, and outboard servo inclinometer 24 provide voltages propor ⁇ tional to the sine of the tilt angle.
• Servo inclinometers 20, 22, and 24 utilized in the present system embodiment comprised model LSOC-90 type servo inclinometers manufac- tured by Schaevitz Engineering, Inc., of Pennsauken, New Jersey. These servo inclinometers produce a voltage of + 5 volts corresponding to Sin C+ 90°) . As a consequence it is necessary for the signal processing downstream to perform an arc sine CSin ⁇ operation on the signals in order to recover and display the angle of inclination.
• V /6 is relatively small compared to V for ⁇ less than or equal to
• the output of the reference transducer can be displayed independently, where the difference between the inboard or outboard flap angle relative to the reference angle can also be selected.
• IC1 is an instrumenta ⁇ tion amplifier; the gain is set at 4.00.
• IC4 and IC5 are four quadrant multipliers that provide the second term to the inverse sine approximation. Summing and scaling is done by IC6. The final subtraction is done by digital panel meter 100 which has differential input.
• IC8 and IC9 perform further similar functions respectively as IC4, IC5 and IC6 hereinbefore discussed.
• IC100 of Figure 5B performs same function as ICl and IC2 hereinbefore discussed. of further interest in the circuit embodiment of
• FIG. 5A, 5B, and 5C is that there is further included a power supply and battery protection circuit.
• the system is designed such that it can be powered by 115VAC 60 hZ or by its internal battery.
• the battery charging circuitry consists of IC10 and IC11.
• IC10 limits the maximum charg ⁇ ing voltage to 47.0 volts + . 0.5 volt.
• Transistors Ql and Q2 form the battery ⁇ &iutdown circuitry. When the voltage on the collector of Ql goes below 32 volts + 0.5 volt, Q2 will be turned off and Ql will then be off, IC12 regulates the battery output voltage to 30.0 volts + 0.3 volts.
• Q5 together with Q3 and Q4 form a power splitter circuit to provide the + 15 volts DC to power transducers 22, 24 and 26 and other circuitry.
• IC14 supplies the +5VDC required by display meter 1Q0,
• Exemplary parts in the circuit schematic of Figures 5A - 5B include:

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Aviation & Aerospace Engineering (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

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• 1982
  • 1982-09-30 EP EP19820903384 patent/EP0120003A4/fr not_active Withdrawn
  • 1982-09-30 WO PCT/US1982/001386 patent/WO1984001426A1/fr not_active Application Discontinuation

Non-Patent Citations (2)

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