RU2445234C2 - Helicopter safety system for critical flying conditions - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to aircraft engineering and may be used in developing helicopters with in-line rotors. Proposed system comprises set of transmitters, analysis unit and set of receivers. Receiver outputs are connected to first set of data inputs of analysis unit. Analysis unit output is connected via onboard computer with helicopter control and/or indication components. Second set of data inputs s connected with appropriate set of onboard computer outputs.

EFFECT: helicopter safety.

3 cl, 3 dwg

Description

The invention relates to the field of aircraft construction and can be used to create helicopters, primarily with coaxial propellers designed to work in particularly difficult conditions, to increase crew safety and machine reliability.

Optical security systems are known, for example, a system containing optical sensors and an optical information processing unit that records the passage of propeller blades against the sky and filters false information (see UK Patent No. 2286666, B64C 27/00, 1995).

The disadvantages of optical systems include structural complexity, significant dimensions and high cost.

It is also known the use of vibration sensors to determine the magnitude of the imbalance of the propeller blades (see US patent No. 3795375, B64C 27/00, 1974).

However, the vibration of the blades is only an indirect and optional consequence of the imbalance, and the imbalance and vibration themselves are not sufficient diagnostic criteria. Therefore, the reliability of the known device is small.

Closest to the proposed is a helicopter safety system containing an antenna emitting a signal in the direction of the rotating rotor blades. The antenna impedance changes when one of the blades passes, depending on the distance and modulates the carrier frequency, for which, in addition to the antenna, the known device also has a generator, receiver and processing unit (see US Patent No. 6448924, B64C 27/00, 1999 ) Thus, the known system comprises at least one transmitter and a detector, the output of the latter being connected to the input of the processing unit.

The disadvantages of the known security system include insufficient sensitivity and narrow functionality. Low sensitivity is associated with design features and the way to highlight useful information (by changing the antenna impedance). The same can be formulated differently: the well-known scheme for extracting information about the position of the blades does not allow increasing sensitivity due to the significant influence of interfering factors, in particular, the influence of neighboring blades, especially in a coaxial scheme. The lack of functionality of the known device is due to the fact that it does not take into account the flight mode and does not allow to take into account the position of the two propeller blades relative to each other and the helicopter body and a number of other parameters. All this not only limits the capabilities of the system, but also reduces its effectiveness.

The technical result expected from the use of the invention is to increase the safety of the helicopter, increase the efficiency of the security system by increasing its sensitivity and expanding functionality.

The specified result is achieved by the fact that the known helicopter safety system in critical modes, containing a group of transmitters and a processing unit, is equipped with an analysis unit and a group of receivers whose outputs are connected to the first group of information inputs of the analysis unit, the output of which is connected via the on-board computer to controls and / or helicopter indications, the second group of information inputs of the analysis unit being connected to the corresponding group of outputs of the on-board computer.

Moreover, groups of transmitters and receivers can be located on one and the other screws of the coaxial helicopter.

In addition, groups of transmitters and receivers located on the helicopter structural elements can form a multiply connected system for recording deviations in the spatial position of structural elements from normal.

Figure 1 shows the placement of system elements on the structural elements of the helicopter. Figure 2 illustrates a block diagram of a security system. Figure 3 shows an example of building a multiply connected system for recording deviations of the spatial position of structural elements from normal.

The system (figure 1) contains a receiver 1 and a transmitter 2 (or a transmitter 1 and a receiver 2) located on the blades 3, 4 of the coaxial screws. One or more receivers or transmitters 5 can be located on the housing 6 of the helicopter, in the same way, the receiver or transmitter 7 can be placed on the tail boom or tail unit 8.

In other words, a group 9 of transmitters 10 and a group 11 of their respective receivers 12, capable of receiving the signal of one or more transmitters 10, as shown by a curly arrow (figure 2), are placed on the helicopter body and screws. The transmitters are energized by the frequency of the generators 13, and the signal from the output of the receivers 12 is supplied to the corresponding amplitude detectors 14. The outputs of the detectors 14 are connected to the first group of information inputs of the analysis unit 15, the output of which is connected to the newly formed input of the on-board computer 16. From block 15 to this input information is used that is used in the calculator 16 to control the helicopter controls 17 and / or indicating means (warning the crew or ground services), also conditionally indicated in FIG. her 17. Position 18 denotes sensors that give the input of the calculator 16 information about the wind load, speed, altitude, heading and other flight parameters. After processing, this information from the output of the calculator 16 is fed to the second group of information inputs of the analysis unit 15.

As shown in FIG. 3, two receivers 12 can be located on the housing 6, three on the upper propeller blades 3, and one transmitter 12 on the tail unit 19. Transmitters 10 can be located on the lower screw blades 4 (three), on the tail element 20 (one), on the wing 21 (one). The transmitters 12 are connected by lines to receivers 10 tuned to their frequency, so that the lines in Fig. 3 show communications in a multiply connected system for recording deviations of the spatial position of structural elements from normal. So, the transmitter 12 on the housing 6 is connected with two receivers on the blades 4 and one on the wing 21, etc. The connections are established from the conditions: the data from the receivers 12 about their position relative to the associated transmitters 10 should be sufficient to determine the relative position of all structural elements on which the transmitters 10 or receivers 12 are installed, and the number of connections in the system is not excessive. This condition can be fulfilled by solving the corresponding system of equations, and also by first establishing the connection of all receivers 12 with all transmitters 10, and then alternating long-distance communications and checking the sufficiency of information, i.e. the ability to determine the relative position of all structural elements.

The system operates as follows. Near critical flight conditions, with sharp maneuvering and strong wind load, deformation of the blades and other helicopter design elements can occur. The magnitude of this deformation is fixed by the magnitude of the amplitude of the signal received by the receiver 12. The latter is allocated by the detector 14, made, for example, in the form of a series-connected amplitude detector and an analog-to-digital converter.

This information goes to block 15, in which all or several of the following operations are performed:

- data on the amplitude of the signals from the output of the detectors 14 are converted into data on the magnitude of the deformation of the structural elements of the helicopter, the magnitude of the deviation of their position from normal,

- these deviations are compared with previous values, and the forecast on the development of the situation is made by the value of the derivatives,

- these deviations and / or derivatives are compared with threshold values or

- based on these values for a set of links in a multiply connected system for recording deviations in the spatial position of structural elements from normal, a complex hazard indicator, the probability of an emergency,

- when calculating this indicator, information on the service life of structural elements and the time elapsed since the replacement or repair of individual elements is stored in block 15 or calculator 16 is used;

- when calculating the indicator and / or predicting the development of the situation, information is also used on the speed, loads, position of the controls. This data comes from the calculator 16,

- signals are generated that correct the pilot’s actions or give him information about the proximity of critical modes and ways to prevent an emergency.

As noted above, the system is designed primarily for coaxial-type helicopters, where at critical angles and accelerations the blades of 3, 4 rotors can come close to mutual contact and destruction, but can also be useful for observing the behavior of rotor blades in other schemes aircraft.

The system measures in real time the relative position of its elements (transmitters 10 and receivers 12) located in the blades 3, 4 (if necessary - at several points, but mainly at the ends where the deformation is maximum), as well as, for example, on the tail boom and elements of plumage.

The system fixes the mutual distance between the elements of the blades 3, 4 screws at the moment of their passage above each other (rapprochement), as well as, if necessary, the position of the sensors of the blades 3, 4 relative to the sensors on the housing 6 (tail unit, etc.). According to the measurements in real time, the relative position of the screws is determined, as well as their position in relation to the elements of the machine body.

The measurement results, as well as the derivatives of the motion of the blades (speed, acceleration, etc.) calculated on them, allow us to predict trends and determine the proximity of critical modes. This information allows you to adjust the control of the system accordingly (for example, by vibration on the helicopter control handle or otherwise indicate to the pilot about the proximity of the critical mode or introduce automatic restrictions (including, for example, with a change in force or restriction on manual controls).

As noted above, to clarify the prediction of the behavior of the blades and the aircraft as a whole, it is advisable to enter additional information into block 15, for example, about the current speed and direction of the aircraft motion vector, as well as the speed and direction of the air flow.

Example 1. Three transmitters 10 with unique signals are located at the ends of three blades 4 of the lower screw of the coaxial twin-screw circuit, and three receivers 12 are located at the ends of the blades 3 of the upper screw (signals can be fed and received using the wiring elements already existing in the blades or the signal can be radio channel, and the power is autonomous, with induction charging). Additional receivers 12 can be placed on the tail boom and feathering elements, near which also passes when the rotation of the blade 4 of the lower screw. When each pair of transmitter-receiver converges, receiver 12 extracts and recognizes the individual signal of each transmitter 10 and determines its distance from its maximum amplitude (the computing part can also be performed in a single unit for the system or in the receiver and in the general unit to increase the reliability of the system in case of damage - while the information coming from the receiver 12 can be minimized, transmitted reliably and with redundancy, as is usually the case with security systems).

Sensors on the blades show the relative position and shape of two counter-rotating cones of the rotors, and the sensor (or sensors) on the tail boom and other structures give a reference to the position of these rotation figures in the coordinate system, for example, the helicopter as a whole.

Example 2. All sensors (pair receiver 12 - transmitter 10) are made in the form of transceivers, where any pair exchanges signals in the opposite direction (but independently, which is more reliable, although the request-response mode is also possible). All signals are electromagnetic, and the antennas in the simplest case are flat coils. The nature of the signals in terms of power and spectrum must satisfy the requirements of electromagnetic compatibility with other onboard systems and have noise immunity in relation to powerful ground-based radiating systems.

The system allows for various calibration methods and provides survivability in the event of failure of one or more sensors.

Additionally, the archived information of the proposed system may be useful for assessing the actual resource of the blades, gearbox, etc. (due to the permanent measurement of deformations and accelerations), which can be taken into account both for timely replacement (which also increases safety), and for automatic (for example) change of limit constants indicating critical conditions - for kits with high wear or at the end of their service life .

In addition, it is possible to diagnose damage to the blades and fasteners in real time by changing or abnormal behavior during various evolutions. By modulating the amplitude of the sensor signal, one can detect and measure the vibration of the blade with a defect (by determining the number of the defective blade by the elimination method, analyzing the signals of all sensors for the presence of the modulation nature).

Thus, the proposed solution is designed to improve flight safety, increase maneuvering efficiency (by introducing reasonable and appropriate restrictions on control, instead of existing ones, they are chosen strictly, with large reserves, but still not always sufficient). The proposed tools are most effective when flying and maneuvering in mountainous conditions, as well as when operating at sea, in difficult weather conditions and under other restrictions (landing on the deck, etc.).

Claims (3)

1. The helicopter safety system in critical modes, comprising a group of transmitters, characterized in that it is equipped with an analysis unit and a group of receivers whose outputs are connected to the first group of information inputs of the analysis unit, the output of which is connected via the on-board computer to control and / or indication bodies helicopter, and the second group of information inputs of the analysis unit is connected to the corresponding group of outputs of the on-board computer. 2. The system according to claim 1, characterized in that the group of transmitters and receivers can be located on one and the other coaxial screws of the helicopter. 3. The system according to claim 1, characterized in that the groups of transmitters and receivers located on the structural elements of the helicopter form a multiply connected system for recording deviations of the spatial position of structural elements from normal.

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