RU2429165C1 - Device for cargo soft parachute landing on landing ground - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: proposed device comprises parachute, halyard fastening parachute to cargo, halyard automatic lock, altitude pickup, control unit, cable circuit to interconnect control unit and halyard automatic lock. Parallel with halyard automatic lock, linear elastic element is secured.

EFFECT: ruling out negative effects on cargo and landing surface.

3 dwg

Description

The invention relates to the fields of technology where parachutes are used to lower objects in the atmosphere. It can be used for shock-free landing of returned spacecraft or landing cargo.

An integral property of a parachute landing is the presence of a vertical descent rate. A decrease in the magnitude of this speed is associated with an increase in the size of the parachute, the volume and mass of the parachute system. To reduce the vertical speed to acceptable values, a parachute system of acceptable mass and volume is used, and before touching the landing surface, a special braking device is activated. There are two main methods of braking the cargo, launched by parachute, before touching the landing surface: 1) using shock absorbers [1], for example, according to the application of the Russian Federation No. 92015245 IPC V64C 25/28, 2) using reactive brakes [1, 2], for example, RF patent No. 2272757.

Various designs of shock absorbers are known, the simplest are felt or other gaskets placed between the cargo and the landing platform. Breakable stands, honeycomb structures, springs, hydraulic brakes, pneumatic devices in the form of bags filled with air, etc. are more complex. The described devices increase the height of the center of mass of the load above the lower surface of the shock absorber [1], since a certain braking distance is required to ensure a given overload . This creates a large tipping moment with the horizontal movement of the cargo relative to the ground with the wind speed, which is the main disadvantage of the described shock absorbers.

The main part of the jet brake is the engine, in which the combustion of fuel occurs, and from the nozzle of which the combustion products flow out at high speed. The jet of exhaust gases creates a reactive force, which is used as the braking force of the cargo dropping by parachute. A significant difference between the reactive brake and various shock absorbers is that the load can be braked over a long braking distance, while shock absorbers with a large braking path are not applicable, since the distance from the center of mass of the load to the lower surface of the shock absorber at the moment of touching the landing surface is large and the load tipping over, especially in the presence of wind.

The closest technical solution, selected as a prototype, is a soft landing system with a jet brake, for example, according to the application of the Russian Federation No. 94019768, IPC VV 1/06. Common with the claimed device is:

- the introduction of a reactive brake according to the results of measuring the height to the landing surface.

The main disadvantages of soft landing systems on jet brakes are:

- the presence in the landing system of stockpiles of explosive rocket fuel;

- the complexity of propulsion systems and the need for duplication;

- the possible destructive effect of engine jets on the landing surface with negative consequences for both the surrounding space and the cargo;

- strong vibroacoustic impact on the load.

The proposed device soft parachute landing allows you to eliminate the negative effects on the landing surface and the laden load, increase safety, reduce weight and simplify the landing system compared to the prototype.

The problem is solved due to the fact that in the device containing the parachute, the halyard connecting the load with the parachute, the height sensor, control unit, cable network, automatic lock of the halyard connecting the parachute and the load, a linear elastic element with known dynamic properties and when the estimated height above the landing surface, which depends on the speed of the cargo parachute system and the characteristics of the elastic element, is reached, the halyard connecting the cargo with the parachute is broken in the area between the points of attachment of the elastic element to the halyard, due to the automatic locking of the halyard, the load is accelerated by gravity and potential energy is accumulated in the elongating linear elastic element, then the energy stored in the elastic element is used to slow down the load due to accelerated movement parachute in the compression phase of the elastic element, providing a vertical load speed at the moment of touching the landing surface close to zero.

The novelty of the proposed technical solution lies in the use of a linear elastic element integrated into the parachute suspension as a mechanical energy accumulator, which is then used to damp the vertical speed of the load.

In practice, cases of using a linear elastic element to provide a soft parachute landing are not known.

Figure 1 shows a diagram of a device with the main functional elements:

1 - parachute;

2 - linear elastic element;

3 - cargo;

4 - halyard;

5 - automatic lock halyard;

6 - cable network;

7 - control unit;

8 - height sensor.

The load (3) is connected to the parachute (1) using a halyard (4). The cargo (3) or halyard (4) contains a height sensor (8) and a control unit (7). In parallel with the halyard (4), a linear elastic element (2) is fixed. On the halyard (4), between the attachment points of the linear elastic element (2), there is an automatic hitch lock (5). The electrical connection between the control unit (7), the height sensor (8) and the automatic hitch lock is carried out using a cable network (6).

The device operates as follows. Initially, the load (3) moves by parachute (1) with a constant vertical speed. Automatic halyard lock (5) is closed. Linear elastic element (2) is not loaded. Data on the rigidity of the linear elastic element (2), the weight of the laden load (3) and the aerodynamic characteristics of the parachute (1) are entered in the control unit (7). During the flight, the height sensor (8) constantly detects the height of the load (3) above the landing surface. On the cable network (6), these data are sent to the control unit (7), which calculates the possible trajectories of the movement of the system load (3) - elastic element (2) - parachute (1). Upon reaching a height at which, according to the trajectory calculations, the control unit (7) realizes zero vertical speed of touching the landing surface, the control unit (7) sends a command to open the automatic file lock (5) via the cable network (6). The tight connection between the load (3) and the parachute (1) is broken. Under the action of gravity, the load (3) begins to move down accelerated. The parachute (1) is then braked due to uncompensated aerodynamic force. Linear elastic element (2) is loaded, storing potential mechanical energy. After some time, the elastic force of the linear elastic element (2) increases to such a value that it starts to slow down the load (3) and accelerate the parachute (1). The vertical speed of the load (3) drops to zero. At this moment, the load (3) touches the seating surface.

Figure 2 shows a schematic diagram of the operation of the landing system. The landing surface is schematically shown below, the axis with the height H on the left is the distance between the lower point of the load (3) and the landing surface. The four stages of the planting process are depicted.

A - the first stage, characterized by the steady movement of the cargo - parachute system with a soft parachute landing device and reaching the height at which the automatic halyard lock opens (5);

B - the second stage, in which there is an accelerated downward movement of the load (3) and the accumulation of potential energy in the linear elastic element (2);

C is the third stage. The linear elastic element (2) is compressed and the load is braked (3);

D - the fourth, final stage of soft parachute landing with a vertical speed close to zero.

Figure 3 shows a graph of the dependence of the height of the load (3) above the landing surface on time. The moment of time 0 corresponds to the moment of opening the automatic file lock (5). At 11 seconds, the trajectory has a shelf and an inflection, i.e. zero first and second derivatives (zero vertical speed of the load (3)).

The present invention can be implemented, for example, as follows.

Initially, a load (3) of mass M = 8000 kg moves on a rigid hitch through a halyard (4) with a parachute (1), the aerodynamic drag coefficient of which is C = 545 kg / m in the Earth’s atmosphere. The speed of the system is constant V = 12 m / s. One end of the halyard mount (4) is secured through the automatic hitch lock (5). In parallel with the automatic hitch lock (5), a linear elastic element (2) with a hardness of k = 1500 N / m is fixed. It can be made of rubber with an elastic modulus of E = 5 MPa. In the steady state, after the parachute (1) is inserted, the load system (3) - the halyard (4) with a linear elastic element (2) - the parachute (1) moves on a rigid hitch at a constant speed, because the gravity of the load is compensated by the aerodynamic drag of the parachute. In this case, the linear elastic element (2) is not loaded. The distance (height H) from the load (3) to the landing surface is continuously measured by the height sensor (8) and information is transmitted via the cable network (6) to the control unit (7). The control unit (7), using data on the characteristics of the load (3) - linear elastic element (2) - parachute (1) and height measurements, determines the moment of opening the automatic file lock (5). In the considered example, when reaching a height of 185 m to the landing surface, the control unit (7) issues a command via cable network (6) to open the automatic file lock. The force of gravity acting on the load (3) causes its accelerated movement to the landing surface, while the aerodynamic force acting on the parachute (1) slows down the latter. The linear elastic element (2) is stretched and potential energy is accumulated in it. With a certain stretching of the linear elastic element (2), the elastic force on it exceeds the weight of the load (3) and the load is braked (3) and the parachute is accelerated (1). A graph with the dependence of the height over time is shown in Fig.3. As can be seen from the graph in Fig. 3, at the moment the cargo (3) touches the landing surface, the cargo height (3) and its first time derivative are close to zero. As a result, the load (3) reaches the landing surface at a speed close to zero.

This invention allows:

- reduce safety requirements in the manufacture and operation due to the exclusion of explosive substances in the system;

- reduce the weight of the soft landing device compared to systems based on jet engines;

- minimize the negative impact on the external environment and the landing surface;

- the device is reusable.

Literature

1. Lobanov N.A. Fundamentals of calculation and design of parachutes. - M.: Mechanical Engineering, 1965 .-- 364 p.

2. Gerasimenko I.A., Komov I.A. Airborne training. Part 3. Parachute-reactive systems and their application. - M: Ministry of Defense of the USSR. Military Publishing House, 1989 .-- 224 p.

Claims (1)

A device for soft parachute landing of cargo on a landing surface containing a parachute, a halyard connecting the load with a parachute, an automatic halyard lock, a cable network connecting an altitude sensor, a control unit and an automatic halyard lock, characterized in that in the halyard section with an automatic lock, it is parallel to the automatic the halyard lock is rigidly fixed to a linear elastic element with predetermined characteristics.

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