CN116119062A - Design method of unmanned aerial vehicle integrated emission recovery system - Google Patents
Design method of unmanned aerial vehicle integrated emission recovery system Download PDFInfo
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Abstract
The invention provides a design method of an unmanned aerial vehicle integrated emission recovery system, which comprises an energy absorption and release module, a guide rail module and a driving cable module; the energy absorption and release module comprises a step 1, wherein an unmanned aerial vehicle integrated emission and recovery system structure is designed; step 2, designing a process of unmanned aerial vehicle emission and recovery and determining parameters; step 3, designing a control strategy of the energy accumulator in the process of emission and recovery of the unmanned aerial vehicle; and 4, designing the energy accumulator according to a control strategy of the energy accumulator. The invention adopts a hydraulic system for emission and recovery, and is suitable for the emission and recovery of medium-sized unmanned aerial vehicles with the weight of 400kg and the speed of 140 km/h. The weight and size of the system are reduced, and the adaptability and flexibility of the system to complex terrains and special situations are increased.
Description
Technical Field
The invention relates to the technical field of unmanned aerial vehicle protection, in particular to a design method of an unmanned aerial vehicle integrated emission recovery system.
Background
The existing small and medium unmanned aerial vehicle is generally launched and recovered by adopting independent systems, the unmanned aerial vehicle is launched by adopting rubber band ejection, hand throwing and taking off, rocket boosting, pneumatic ejection and other modes, and the unmanned aerial vehicle is recovered by adopting parachute recovery, net collision recovery, sky hook recovery and other modes.
In the mode, the rubber band ejection, the hand throwing and taking-off and the rocket boosting emission are mainly aimed at small unmanned aerial vehicles, the application is less in medium-and-large unmanned aerial vehicles, the emission mode of air pressure or air-liquid is mainly adopted in the prior art, and the friction or hydraulic braking mode is mainly adopted in the blocking recovery to convert kinetic energy into heat energy.
Disclosure of Invention
The invention aims to provide an integrated take-off and landing guarantee device for a small and medium unmanned aerial vehicle, which can be arranged on land or a ship and can be used for designing an integrated system with the functions of emission and recovery.
The design method of the unmanned aerial vehicle integrated emission recovery system comprises the following steps:
in step 1, the unmanned aerial vehicle integrated emission recovery system comprises an energy absorption and release module, a guide rail module and a driving cable module;
the energy absorbing and releasing module comprises a hydraulic cylinder, a movable fixed pulley block and an energy accumulator; the hydraulic cylinder adopts a double-acting oil cylinder, the hydraulic cylinder comprises an oil cylinder piston rod, the end part of the oil cylinder piston rod is connected with the movable fixed pulley block, and the hydraulic cylinder is provided with an oil emission port and an oil recovery port; the movable fixed pulley block comprises a movable pulley block and a fixed pulley block; the movable pulley block 2 comprises a pulley seat and a plurality of parallel and coaxial pulleys, and the pulley seat is fixedly connected with the head of the cylinder piston rod; the fixed pulley block 3 consists of a plurality of parallel and coaxial pulleys, and the fixed pulley block 3 is fixedly connected with the ground; the energy accumulator comprises a transmitting energy accumulator and a recovery energy accumulator, the transmitting oil port is connected with the transmitting energy accumulator, and the recovery oil port is connected with the recovery energy accumulator;
the driving cable module comprises a steel cable, one end of the steel cable is connected with the guide rail module, and the other end of the steel cable is connected with the energy absorbing and releasing module;
the guide rail module comprises a guide rail, a sliding block, a transmitting frame, a recovery rope and a pulley net; the guide rail is fixedly arranged, the sliding block is matched with the guide rail and can move along the guide rail, one end of the sliding block is rigidly connected with the steel cable, and the sliding block is connected to the hydraulic cylinder through the movable fixed pulley block; the launching frame, the recovery rope and the pulley net are connected with the sliding block. Wherein the recovery cable and the pulley net are connected with the slider only in the recovery state, and the launching cradle is mounted with the slider only in the launching state.
Further, in step 1, the drive cable module includes a recovery damper including a movable sheave, a damper, a first guide sheave and a second guide sheave; the first guide pulley and the second guide pulley are fixedly arranged, the shaft of the movable pulley is connected with the damper, and the steel cable sequentially bypasses the first guide pulley, the movable pulley and the second guide pulley.
Further, in step 2, the integrated emission recovery system of the unmanned aerial vehicle determines the emission weight m and the emission speed v of the unmanned aerial vehicle, the working stroke s of the guide rail, and the mass of the traction trolley of the initial emission frame is m 1 The average emission thrust is:
F average of ＝(m+m 1 )a
Wherein the acceleration is
s is the rail working stroke, m is the emission weight of the unmanned aerial vehicle, m 1 The weight of the traction trolley is as the weight of the traction trolley;
meanwhile, when the transmission and the recovery are considered, the penetrating and winding ratio of the movable fixed pulley block is 1: z;
the main parameters of the hydraulic system are calculated as follows:
maximum speed reached by the piston rod:
working stroke of the hydraulic cylinder:
the diameter D of the inner cavity of the hydraulic cylinder is initially determined, the diameter D of the piston rod is determined, and the effective area of the rod cavity of the hydraulic cylinder is
The hydraulic cylinder has the maximum flow rate that the pole chamber reaches: q (Q) With rod cavities ＝S Effective and effective ·V Cylinder with a cylinder body ；
The volume of oil required in the launching process is as follows:
ΔV＝S effective and effective ·L Cylinder with a cylinder body
Effective area of hydraulic cylinder rodless cavity:
the maximum flow rate reached by the rodless cavity of the hydraulic cylinder is as follows: q (Q) Rodless cavity ＝S Rodless ·V Cylinder with a cylinder body ；
The average pressure required by the rod cavity during the hydraulic cylinder emission is as follows:
initially setting the total volume of gas in the accumulator to be V when the accumulator is to be launched 1 The volume after emission is V 2 The method comprises the steps of carrying out a first treatment on the surface of the Namely:
initially, the following steps:
wherein ：P1 To the pressure of the accumulator during firing, P 0 For initial pressure of accumulator, V 0 N is the insulation for the initial volume of the accumulatorA bar index;
at the end, the method comprises the following steps:
further, in step 2, the recovery process is checked and calculated using the firing parameters, and the determined firing and recovery process parameters are determined as a whole, including the effective length of use of the rail, the wire rope system winding ratio, the maximum travel of the hydraulic cylinder, the hydraulic cylinder bore diameter, the piston rod diameter, the maximum working pressure of the hydraulic cylinder, and the accumulator volume.
Further, in step 3, for the launching process, models of moving components such as pulleys, cables, accumulators and cylinders are respectively built, the transmission ratio at the movable pulleys and the accumulator-cylinder model are designed according to a system schematic diagram, and the specific calculation model of each subsystem comprises:
the pulley system, assuming clockwise rotation is positive, can be equivalently:
(F i+1 -F i -F fi )R＝Jα
wherein ：Fi+1 Tension for the i+1st section of rope; f (F) i Tension for the i-th rope;
r is the radius of the pulley; j is the rotational inertia of the pulley assembly; alpha is the angular acceleration of the pulley assembly;
wherein, pulley assembly rotating member is approximately ring plane board, and its moment of inertia J can be expressed as:
the relationship between the angular acceleration α and the linear acceleration a is: a=αr;
wherein: m is the weight of the pulley assembly revolution body, R is the diameter of the outer circle, and R is the diameter of the inner circle;
wherein ,
can be considered as equivalent mass of a single sheave assembly;
according to hooke's law, any piece of rope tension is calculated:
e is the elastic modulus of the rope; a is the effective cross-sectional area of the rope; Δl is the elastic elongation of the rope; l is the length of the rope;
the amount of deformation for the segment 1 rope can be expressed as:
ΔL＝S i -S f
the amount of deformation for the 2 nd-6 th rope can be expressed as:
ΔL＝S g +S i+1 -S i
S g for the displacement of the oil cylinder S i+1 Is the rotation quantity of the (i+1) th pulley, S i Is the rotation amount of the ith pulley;
calculating a hydraulic system, according to the working process of the hydraulic system, transmitting and instantaneously controlling a flow control valve to be opened, enabling high-pressure oil in an energy accumulator to enter an oil cylinder, pushing the oil cylinder to retract quickly, and further driving an aircraft to accelerate, wherein the transmission process is faster (less than 1 s) and does not perform remarkable heat exchange with the outside, the process can be regarded as an adiabatic process, 3 state quantities of P, V, T and the like of gas are changed simultaneously in the adiabatic process, and the adiabatic process between P, V is PV 1.4 ＝P 0 V 0 1.4 The pressure change during the firing process can be calculated from the volume change, and the pressure change in the accumulator satisfies the following equation:
wherein ：P1 Is the pressure of the accumulator during firing; p (P) 0 Is the initial pressure of the accumulator; v (V) 0 Is the initial volume of the accumulator;
V 1 the volume of oil entering the oil cylinder;
the accumulator enters the oil cylinder through the large-flow control valve, a certain throttling pressure difference is generated when the flow control valve is opened, and the pressure in the oil cylinder can be obtained according to a flow equation to meet the following formula:
wherein ρ is the oil density, Q is the flow, C d Is the flow coefficient, A o Is the area of the overcurrent;
the flow Q can be expressed as:
Q＝AV g
the movement of the piston cylinder meets the following conditions:
V g ＝a g dt
wherein ,ag Is the acceleration of the moving part of the oil cylinder,
m is the sum of the rope tensions acting on the cylinders f The weight of the oil cylinder moving part;
F g ＝P 1 A
wherein A is the effective area of the oil cylinder moving part;
and (3) calculating the unmanned aerial vehicle, wherein for the emission of the unmanned aerial vehicle, the motion process of the unmanned aerial vehicle meets the following formula:
V f ＝a f ×dt
a f ＝(F 1 -F f )/M f
wherein ,Vf Is the speed of the unmanned aerial vehicle, a f Acceleration of unmanned plane, F f Resistance, M, applied to unmanned aerial vehicle in motion process f For unmanned aerial vehicle weight, F 1 Is the rope tension to which the unmanned aerial vehicle is subjected.
Further, in step 3, the model of the recovery process mainly comprises a pulley system, a hydraulic system and an unmanned aerial vehicle, wherein the pulley system calculation model is basically consistent with the emission, and the motion model of the pulley is as follows:
the amount of deformation of the rope, as opposed to the firing process, can be expressed as:
ΔL＝S f -S i
the amount of deformation for the 2 nd-6 th rope can be expressed as:
ΔL＝S i -S i+1 -S g
wherein ,Sg For the displacement of the oil cylinder S i+1 Is the rotation quantity of the (i+1) th pulley, S i Is the rotation amount of the ith pulley;
equation of motion for unmanned aerial vehicle:
a f ＝(-F 1 -F f )/M f
calculation of hydraulic systems
The motion equation of the oil cylinder motion piece is as follows:
V g ＝a g dt
for hydraulic force F g ＝P 1A, wherein P1 Is the cylinder pressure, the cylinder pressure P 1 Can be expressed as:
P 1 ＝P 0 +ΔP
wherein ,P0 As accumulator pressure, ΔP is throttle differential pressure;
wherein ρ is the oil density, Q is the flow, C d Is the flow coefficient, A o Is the area of the overcurrent.
The flow Q can be expressed as:
Q＝AV g
wherein ,P0 For accumulator pressure, this can be expressed as:
wherein ,V0 For the initial volume of the accumulator, V 1 For volume change of accumulator, V 1 ＝S g A。
The beneficial effects of the invention include:
the invention adopts a hydraulic system for emission and recovery, and is suitable for the emission and recovery of medium-sized unmanned aerial vehicles with the weight of 400kg and the speed of 140 km/h.
The emission system and the recovery system adopt an integrated structure, and can structurally share part components such as an energy absorption and release system, a guide rail system, a driving cable system, an auxiliary system and the like, so that the two functions can be switched, and the main part kit can realize integrated sharing; the weight and size of the system are greatly reduced, and the adaptability and flexibility of the system to complex terrains and special situations are also increased.
The invention adopts the module and integrated design, can be more suitable for the development demands of future high-frequency emission tasks, high-efficiency recovery tasks, high-speed unmanned aerial vehicles, high-automation operation, low manpower and the like on ships, and is beneficial to realizing rapid deployment and storage.
Drawings
Fig. 1 is a schematic flow chart of a design method of an integrated emission recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an integrated emission recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an emission process of an integrated emission recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a recovery process of an integrated emission recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 5 is a schematic diagram of acceleration curves of an ideal launching process in a design method of an integrated launching and recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 6 is an ideal graph of acceleration of an launching process using an accumulator as power in a design method of an integrated launching and recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 7 is an ideal graph of acceleration during recovery in the design method of the integrated emission recovery system of the unmanned aerial vehicle according to the embodiment of the invention;
fig. 8 is a simplified model schematic diagram of an unmanned aerial vehicle launching process in a design method of an unmanned aerial vehicle integrated launching and recovering system provided by an embodiment of the invention;
fig. 9 is a schematic diagram illustrating a comparison of an opening process of a transmitting process control valve in a design method of an integrated transmitting and recovering system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 10 is a comparative schematic diagram of cable tension under different opening modes of a launching process control valve in a design method of an integrated launching and recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 11 is a schematic diagram showing acceleration comparison of different opening modes of a launching process control valve in a design method of an integrated launching and recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 12 is a schematic diagram of dynamic change of an unmanned aerial vehicle in a launching process in a design method of an integrated launching and recovery system of the unmanned aerial vehicle provided by an embodiment of the invention;
fig. 13 is a schematic diagram of dynamic change of an oil cylinder in a launching process in a design method of an integrated launching and recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 14 is a schematic diagram of tension change of a steel cable in a launching process in a design method of an integrated launching and recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 15 is a schematic diagram of a recovery process model in a design method of an integrated emission recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 16 is a schematic diagram of a motion rule of an unmanned aerial vehicle in a recovery process in a design method of an integrated emission recovery system of the unmanned aerial vehicle provided by an embodiment of the invention;
fig. 17 is a schematic diagram of a recovery process cylinder and a damper in a design method of an integrated emission recovery system of an unmanned aerial vehicle according to an embodiment of the present invention;
fig. 18 is a schematic diagram of the tension of a steel cable during recovery in the design method of the integrated launching and recovery system of the unmanned aerial vehicle according to the embodiment of the invention;
fig. 19 is a schematic diagram of a transmitting accumulator and a control valve group in a design method of an integrated transmitting and recovering system of an unmanned aerial vehicle according to an embodiment of the present invention.
Detailed Description
The technical scheme of the present invention will be described in more detail with reference to the accompanying drawings, and the present invention includes, but is not limited to, the following examples.
As shown in fig. 1, the invention also provides a design method of the unmanned aerial vehicle integrated emission recovery system, which comprises the following steps:
as shown in fig. 2, the unmanned aerial vehicle integrated emission recovery system comprises an energy absorption and release module, a guide rail module, a crane module and a driving cable module.
The energy absorption and release module comprises a hydraulic cylinder, a movable fixed pulley block and an energy accumulator, and is used for providing energy for unmanned aerial vehicle emission or absorbing kinetic energy during unmanned aerial vehicle recovery. The energy accumulator comprises a transmitting energy accumulator and a recovering energy accumulator.
The hydraulic cylinder adopts a double-acting oil cylinder, oil can be communicated in a rod cavity and a rodless cavity, the two-way movement can be realized, a buffer cavity is designed at the bottom of a cylinder barrel of the hydraulic cylinder, a punch is designed at the tail part of a piston rod of the oil cylinder, the punch is in a conical design, and the piston rod can play a role in buffering when moving to the bottom of the cylinder barrel; the hydraulic cylinder is provided with an oil cylinder piston rod, an emission oil port and a recovery oil port, the emission oil port is connected with the emission energy accumulator, the recovery oil port is connected with the recovery energy accumulator, and the end part of the oil cylinder piston rod is connected with the movable fixed pulley block. During launching, high-pressure oil liquid of the launching energy accumulator instantaneously enters the hydraulic cylinder through the launching oil port, and the steel rope generates the tension launched by the unmanned aerial vehicle under the action of the hydraulic force of the hydraulic cylinder; when the unmanned aerial vehicle is recovered, oil in the hydraulic cylinder enters the recovery energy accumulator through the recovery oil port, most of kinetic energy of the unmanned aerial vehicle is consumed by oil throttling, and a small part of energy is stored in the recovery energy accumulator.
The movable fixed pulley block comprises a movable pulley block and a fixed pulley block; the movable pulley block consists of a pulley seat and a plurality of parallel and coaxial pulleys, and the pulley seat is fixedly connected with the head part of a piston rod of the oil cylinder; the fixed pulley block consists of a plurality of parallel and coaxial pulleys, and a pulley seat of the fixed pulley block is fixedly connected with the ground.
The movable fixed pulley block is designed according to a certain transmission ratio, so that the displacement of the oil cylinder is ensured to be proportional to the moving distance of the unmanned aerial vehicle. The energy accumulator is used for storing energy, the pump station is used for pressurizing the energy accumulator before transmitting to form high-pressure energy, and when the high-pressure energy is recovered, the oil in the oil cylinder continuously compresses air after entering, so that the pressure of the energy accumulator is increased, and the energy accumulator is used for resetting the system. The control valve assembly is divided into two paths, one path controls the emission process of the unmanned aerial vehicle according to an emission strategy, the stable emission process is ensured, the other path controls the valve port to be closed according to a preset rule, and further the steel cable force of the recovery process is changed, so that the fluctuation of the recovery process is ensured to be smaller.
The drive cable module includes a cable, a recovery damper, and a plurality of guide pulleys. Each guide pulley is respectively arranged on the guide rail module and the lifting module and is used for changing the trend of the steel cable; the steel cable is a direct force transmission unit and directly acts on the unmanned aerial vehicle; the recovery damper is specially configured for the recovery process, is arranged at the front end of the module, and can rapidly pay out the steel cable and absorb certain aircraft kinetic energy when recovering, so that the tension change on the steel cable is ensured to be more gentle, and the peak tension is smaller.
In one embodiment, the recovery damper consists of a movable pulley, a damper and two guide pulleys; the steel cable sequentially winds the first guide pulley, the movable pulley and the second guide pulley, the two guide pulleys are fixedly arranged, and the shaft of the movable pulley is connected with the damper. The recovery damper is only participated in when unmanned aerial vehicle is recovered, and the penetrating and winding mode of the steel cable can be reserved when unmanned aerial vehicle is launched, but the movable pulley is fixed by the pin shaft, and the recovery damper only plays a guiding role when being launched. The principle of the recovery damper is that an elastic force related to displacement and a damping force related to speed are provided for the module, and the purposes of absorbing impact, reducing shaking of a steel rope and finally reducing recovery overload of the unmanned aerial vehicle are achieved through the matching design of the energy absorption module.
The crane module is arranged on the ground and used for fixing and bearing the guide rail module. In this embodiment, the crane module includes a main arm, a middle arm, a forearm, a rail-connecting arm, and a swing arm mechanism.
The guide rail module comprises a guide rail, a sliding block, a recovery rope, a transmitting frame, a pulley net, a buffer belt component and the like. Wherein the guide rail is a 3 or 4-section folding rail, and the middle section of rail is rigidly connected with the crane module. The sliding block is matched with the guide rail, one end of the sliding block is rigidly connected with the steel cable, and the sliding block is connected to the hydraulic cylinder through the pulley block. The other end is provided with a transmitting frame in a transmitting state, and a recovering rope and a pulley net are arranged in a recovering state, so that the transmitting frame or the pulley net slides along the guide rail under the driving of the steel rope. The pulley assembly is arranged on the guide rail to guide the steel cable in the process of launching and recovery, the launching frame is used for fixing the aircraft during launching, and is matched with the locking mechanism to carry out initial drag on the aircraft and release the aircraft rapidly at the tail end, and the launching frame is only arranged in the launching state. The recovery rope is in a triangular structure and is connected with the sliding block and used for being hooked by the unmanned aerial vehicle in the recovery process of the unmanned aerial vehicle so as to drive the hydraulic cylinder through the sliding block and the steel cable to reduce the speed of the unmanned aerial vehicle; the recovery cord is only installed in the recovered state. The pulley net is connected with the slider, sets up in retrieving the rope rear side for when unmanned aerial vehicle retrieves, after the aircraft hooked the recovery rope, because the inertial effect has certain lift motion, the guipure can protect the aircraft, can prevent after aircraft front end barb device hooks the guipure that the aircraft falls down simultaneously, guarantees that the aircraft steadily stops, and the pulley net is installed only under retrieving the state. The buffer belt assembly comprises a group of buffer braking belts which are fixed on the guide rail and used for stopping the launching frame after the unmanned aerial vehicle launches and takes off.
The general working principle of the unmanned aerial vehicle integrated emission recovery system is as follows:
(1) Principle of unmanned aerial vehicle launching process
As shown in fig. 3, when the system is in the unmanned aerial vehicle launching state, the cylinder piston rod is in a fully extended state, and is connected with the launching frame through a rope by the movable pulley block, the fixed pulley block, the guide pulley, the sliding block and the like, and the unmanned aerial vehicle is placed on the launching frame, so that the preparation work before the unmanned aerial vehicle is launched is completed.
When the unmanned aerial vehicle is started to launch, the launching cylinder is filled with high-pressure oil through the energy accumulator, the launching cradle and the unmanned aerial vehicle are driven to accelerate through the movable pulley block, the fixed pulley block and the like, the unmanned aerial vehicle completes launching action under the action of the launching cylinder, and meanwhile braking of the launching cradle is achieved under the action of the buffer belt component.
(2) Unmanned aerial vehicle recycling process principle
As shown in figure 4, when the system is in the unmanned aerial vehicle recovery state, the cylinder piston rod is in the fully retracted state and is connected with the sliding block through the movable pulley block, the fixed pulley block, the guide pulley and the sliding block, the sliding block is connected with a recovery rope in a triangular configuration, and meanwhile the sliding block is connected with the pulley net in a closed loop through the rope.
When unmanned aerial vehicle colludes the recovery cable, under unmanned aerial vehicle's drive, retrieve the cable and break away from the support frame, drive the slider and follow unmanned aerial vehicle direction motion in the track, and then drive running block and hydro-cylinder motion, produce hydraulic braking force, the coaster net is connected through the closed loop between with the slider simultaneously, follow-up with the slider state, remain the distance of predetermineeing all the time with unmanned aerial vehicle, ensure that unmanned aerial vehicle can accurately collude on the coaster net device in the action of lifting up of retrieving the in-process, unmanned aerial vehicle and coaster net device collude back synchronous motion can be guaranteed to the barb device of unmanned aerial vehicle head, restriction and protection unmanned aerial vehicle.
Note that: if the unmanned aerial vehicle is of a single type, the recovery speed of the unmanned aerial vehicle can be completely controlled before recovery, then the pulley net device can be placed at a fixed position, and when the unmanned aerial vehicle is hooked with the unmanned aerial vehicle in contact with the unmanned aerial vehicle and then the pulley net device is driven, the complexity of a steel cable module and the replacement time in the process of transmitting and recovering conversion are reduced.
(3) Unmanned aerial vehicle transmitting and recycling switching principle
The system can be quickly converted in transmission and recovery, and the system is converted into an unmanned aerial vehicle transmission standby state after recovery by the unmanned aerial vehicle, wherein the process is as follows:
taking down the recovered unmanned aerial vehicle;
taking down the recovery net in the pulley net device, and releasing the closed loop connecting rope between the sliding block and the pulley net device;
taking down the recovery cable of the triangular configuration on the sliding block, and installing an unmanned aerial vehicle launching frame for fixing in the unmanned aerial vehicle launching process;
the sliding block is pulled to the corresponding position of the other end of the guide rail, and a rope of the launching cylinder is fixed with the sliding block;
the movable pulley of the recovery damper is fixed by a pin shaft, so that the movable pulley does not act in the launching process.
in step 2, under ideal conditions, the acceleration of the unmanned plane during launching and recovering should be changed smoothly, the initial acceleration of the plane during launching is zero, the acceleration of the plane is increased to the maximum instantaneously along with the opening of the valve port, and then the acceleration is maintained until the plane launches; the negative acceleration of the airplane during recovery is gradually increased from the minimum to the maximum, and the negative acceleration is reduced along with the reduction of the speed of the airplane after reaching the maximum and being maintained for a period of time.
According to the design scheme of the system, the steel cable is adopted for force transmission in the launching and recovering processes, so that fluctuation of the steel cable is reduced as much as possible in the control design of the launching and recovering processes, and the acceleration in the launching process and the negative acceleration amplitude in the recovering process are reduced.
For the launching process, the launching weight of the unmanned aerial vehicle is 400kg, the launching speed is 140km/h, and according to the preliminary design of the folding guide rail, the working stroke of the folding guide rail is limited to 12m, so that the average acceleration is calculated preliminarily
The acceleration process at the initial stage is considered, and thus an ideal emission process acceleration curve is shown in fig. 5.
If the planned ideal launching process acceleration curve is adopted, the acceleration of the aircraft is slowly increased in the initial stage, because the power transmission is carried out by adopting the steel rope, a certain acceleration section is required to be set for reducing the shaking of the steel rope as far as possible, the pressure oil in the energy accumulator is controlled to gradually enter the launching oil cylinder through the control valve in the acceleration section, the pressure in the oil cylinder is increased, the oil cylinder drives the movable pulley block to accelerate, the steel rope is tensioned, and the aircraft is accelerated. In practice, because the accumulator is used as power, the pressure in the accumulator gradually decreases along with the increase of the gas volume, but the pressure change of the accumulator is relatively small (about 2MPa is designed), so that the acceleration in the launching process can present a certain downward slip, the initial peak value is slightly higher than the theoretical value, and an ideal launching curve using the accumulator as power is shown in fig. 6.
Also based on the length of the rail and the initial aircraft speed, the average negative acceleration during recovery is
The high-speed motion of the aircraft at the initial stage of the recovery process directly acts on the steel cable, the steel cable is necessarily driven to generate fluctuation, and the unmanned aerial vehicle directly acts on an elastic rope led out by a single steel cable when recovering the unmanned aerial vehicle, no triangle transition is caused, so that the initial negative acceleration is necessarily caused to be overlarge, and therefore, with reference to the design concept of the recovery system for the existing ship, a damper is designed at the front end of the system and is used for reducing the impact generated by the hooking rope of the aircraft instantly, the steel cable is rapidly released under the action of the tension of the steel cable, the tension is further reduced, the buffer effect is realized, the damper can absorb certain kinetic energy of the aircraft, a certain elastic coefficient is realized, and the slackening of the steel cable is avoided. The recovery process negative acceleration curve of the ideal state after the buffer is considered is shown in fig. 7.
The unmanned aerial vehicle emission and recovery are the opposite processes of energy release and absorption in the system, under the condition of unmanned aerial vehicle parameter determination, due to the influence of system efficiency, the energy release amount of the system is larger than the energy absorption amount of the system when the unmanned aerial vehicle is recovered, the stress state of the system in the emission process is more severe, and therefore the overall parameter of the system is determined in the emission process, and the recovery process is checked and calculated.
The mass of the traction trolley of the initial transmitting frame is m 1 ＝50kg。
The track friction is negligible, the average launch thrust is:
F average of ＝(m+m 1 )a＝(400+50)×63＝28372N
Meanwhile, when the transmission and the recovery are considered, the stress of the steel ropes at the front end and the rear end of the movable fixed pulley block is different, the penetration and winding ratio of the movable fixed pulley block is not suitable to be large, and the penetration and winding ratio is preliminarily determined to be 1:5.
according to the above requirements, the main parameters of the hydraulic system are calculated as follows:
maximum speed reached by the piston rod:
working stroke of the hydraulic cylinder:
when the diameter d=140 mm of the inner cavity of the initial hydraulic cylinder and the diameter d=70 mm of the piston rod, the effective area of the rod cavity of the hydraulic cylinder is as follows
The hydraulic cylinder has the maximum flow rate that the pole chamber reaches: q (Q) With rod cavities ＝S Effective and effective ·V Cylinder with a cylinder body ＝5386.6L/min。
The volume of oil required in the launching process is as follows:
ΔV＝S effective and effective ·L Cylinder with a cylinder body ＝11539.5×2.4×10 -3 ＝27.7L
Effective area of hydraulic cylinder rodless cavity:
the maximum flow rate reached by the rodless cavity of the hydraulic cylinder is as follows: q (Q) Rodless cavity ＝S Rodless ·V Cylinder with a cylinder body ＝7182.2L/min。
The average pressure required by the rod cavity during the hydraulic cylinder emission is as follows:
and initially selecting an energy accumulator with the volume of 200 liters, wherein the total volume of gas in the energy accumulator is 150 liters when the energy accumulator is to be launched, and the volume after the energy accumulator is launched is 177.7 liters. Namely:
initially, the following steps: p1=15 mpa, v1=150 (L);
at the end, the method comprises the following steps:
V2＝177.7(L)；
the initial inflation pressure was p0= 0.9P2 =10 Mpa.
And (3) checking and calculating the recovery process by using the parameters:
the average negative acceleration of the recovery process is
When the tail hook and the steel wire rope are taken into consideration during recovery, a certain included angle is formed by about 20 degrees, and then the average recovery force is as follows:
after a certain peak-to-average ratio is generated in the recovery process, the peak-to-average ratio is 1.5, and the required maximum recovery force is as follows: f (F) max ＝1.5F Average of ＝40481N。
The maximum speed reached by the piston of the hydraulic cylinder is 7.78m/s, the recovery working stroke is 2.4m which is the same as the emission process, the effective area 11539.5mm < 2 > of the rod cavity of the hydraulic cylinder is the same as the emission process, and the pressure of the rod cavity during recovery is as follows:
in summary, the overall parameters of the emission and recovery process, determined initially by analysis, are as follows:
effective length of guide rail: 12m;
steel cable system penetration ratio: 1:5, a step of;
maximum stroke of the hydraulic cylinder: the thickness is less than or equal to 2400mm;
hydraulic cylinder inner diameter: 140mm, diameter of piston rod: 70mm;
maximum working pressure of hydraulic cylinder: less than or equal to 15MPa;
accumulator volume: 200L.
as shown in fig. 8, for the launching process, models of various motion components such as pulleys, cables, accumulators, cylinders and the like are respectively built, the transmission ratio at the movable pulleys and the accumulator-cylinder model are designed according to a system schematic diagram, and the concrete calculation model of each subsystem comprises:
calculation of pulley system
Assuming clockwise rotation is positive, for any pulley, the course of motion can be equivalent to:
(F i+1 -F i -F fi )R＝Jα
wherein ：Fi+1 Tension for the i+1st section of rope; f (F) i Is the tension of the i-th rope.
R is the radius of the pulley; j is the rotational inertia of the pulley assembly; alpha is the angular acceleration of the pulley assembly.
Wherein, pulley assembly rotating member is approximately ring plane board, and its moment of inertia J can be expressed as:
the relationship between the angular acceleration α and the linear acceleration a is: a=αr.
Wherein: m is the weight of the pulley assembly revolution body, R is the outer circle diameter (pitch diameter), and R is the inner circle diameter (bearing outer ring diameter).
wherein ,
can be considered the equivalent mass of a single sheave assembly.
According to hooke's law, any piece of rope tension is calculated:
e is the elastic modulus of the rope; a is the effective cross-sectional area of the rope; Δl is the elastic elongation of the rope; l is the length of the rope.
The amount of deformation for the segment 1 rope can be expressed as:
ΔL＝S i -S f
the amount of deformation for the 2 nd-6 th rope can be expressed as:
ΔL＝S g +S i+1 -S i
S g for the displacement of the oil cylinder S i+1 Is the rotation quantity of the (i+1) th pulley, S i Is the rotation amount of the ith pulley.
Calculation of hydraulic systems
According to the working process of the hydraulic system, the emission instant control flow control valve is opened, high-pressure oil in the energy accumulator enters the oil cylinder to push the oil cylinder to retract quickly so as to drive the aircraft to accelerate, because the emission process is faster (less than 1 s) and does not exchange significant heat with the outside, the process can be regarded as an adiabatic process, 3 state quantities of P, V, T and the like of gas change simultaneously in the adiabatic process, wherein the adiabatic process between P, V is PV 1.4 ＝P 0 V 0 1.4 The pressure change during the firing process can be calculated from the volume change, and the pressure change in the accumulator satisfies the following equation:
wherein ：P1 Is the pressure of the accumulator during firing; p (P) 0 Is the initial pressure of the accumulator; v (V) 0 Is the initial volume of the accumulator.
V 1 Is the volume of oil entering the oil cylinder.
The accumulator enters the oil cylinder through the large-flow control valve, a certain throttling pressure difference is generated when the flow control valve is opened, and the pressure in the oil cylinder can be obtained according to a flow equation to meet the following formula:
wherein ρ is the oil density, Q is the flow, C d Is the flow coefficient, A o Is the area of the overcurrent.
The flow Q can be expressed as:
Q＝AV g
the movement of the piston cylinder meets the following conditions:
V g ＝a g dt
wherein ,ag Is the acceleration of the moving part of the oil cylinder,
m is the sum of the rope tensions acting on the cylinders f Is the weight of the oil cylinder moving part.
F g ＝P 1 A
Wherein A is the effective area of the cylinder moving part.
Calculation of unmanned aerial vehicle
For the unmanned aerial vehicle's emission, its motion process satisfies following formula:
V f ＝a f ×dt
a f ＝(F 1 -F f )/M f
wherein ,Vf Is the speed of the unmanned aerial vehicle, a f Acceleration of unmanned plane, F f Resistance, M, applied to unmanned aerial vehicle in motion process f For unmanned aerial vehicle weight, F 1 Is the rope tension to which the unmanned aerial vehicle is subjected.
And determining simulation input parameter values according to the parameters determined by the overall scheme.
In the launching process control strategy, in order to reduce the shaking of the steel rope as much as possible, a certain accelerating section is required to be arranged, pressure oil in the energy accumulator is controlled to gradually enter the launching oil cylinder through the control valve in the accelerating section, the pressure in the oil cylinder is increased, the oil cylinder drives the movable pulley block to accelerate, the steel rope is tensioned, and then the unmanned aerial vehicle is accelerated.
Through comparison, when the control valve port is opened according to a certain linear rule, the rope tension jitter is greatly reduced, the acceleration peak value of the unmanned aerial vehicle is obviously reduced, and the emission process is further calculated according to the control strategy, so that the dynamic characteristics of each part of the sleeve member are obtained.
According to the general parameters of the current system, the initial pressure of the accumulator is 15Mpa, the pitch diameter of the pulley assembly is 280mm, the rotational inertia is about 0.07 kg.m2, the cylinder diameter of the oil cylinder is 140mm, the diameter of the piston rod is 70mm, the weight of the steel cable in unit length is 0.45kg, and the friction force of the oil cylinder, the sliding friction force of the pulley and the movement resistance of the unmanned aerial vehicle are roughly estimated and given. The simulation working conditions are as follows: the weight of the unmanned aerial vehicle is 400kg, and the ejection final speed is ensured to be 40m/s. According to the control strategy, the control valves are respectively opened instantaneously by using a simulation model, the control valves are gradually opened for simulation comparison, so that the optimal control strategy is optimized, and the initial simulation pair is shown in the accompanying figures 9-11.
From simulation results, according to the current emission control law, the maximum acceleration peak value during the emission process is about 8.5g, the maximum cable tension is about 35KN, the displacement of the oil cylinder is about 2.5m, and the pressure of the oil cylinder is reduced from 14Mpa to about 11Mpa during the emission process. The simulation results are shown in fig. 12-14.
As shown in fig. 15, similar to the launching process, the model of the recovery process mainly comprises a pulley system, a hydraulic system and an unmanned aerial vehicle, wherein for the pulley system, the calculation model of the pulley system is basically consistent with the launching, and the motion model of the pulley is as follows:
the amount of deformation of the rope, as opposed to the firing process, can be expressed as:
ΔL＝S f -S i
the amount of deformation for the 2 nd-6 th rope can be expressed as:
ΔL＝S i -S i+1 -S g
wherein ,Sg For the displacement of the oil cylinder S i+1 Is the rotation quantity of the (i+1) th pulley, S i Is the rotation amount of the ith pulley.
Equation of motion for unmanned aerial vehicle:
a f ＝(-F 1 -F f )/M f
calculation of hydraulic systems
The motion equation of the oil cylinder motion piece is as follows:
V g ＝a g dt
for hydraulic force F g ＝P 1A, wherein P1 Is the cylinder pressure, the cylinder pressure P 1 Can be expressed as:
P 1 ＝P 0 +ΔP
wherein ,P0 For accumulator pressure, ΔP is the throttle pressure differential.
Wherein ρ is the oil density, Q is the flow, C d Is the flow coefficient, A o Is the area of the overcurrent.
The flow Q can be expressed as:
Q＝AV g
wherein ,P0 For accumulator pressure, this can be expressed as:
wherein ,V0 For the initial volume of the accumulator, V 1 For volume change of accumulator, V 1 ＝S g A。
And determining simulation input parameter values according to the parameters determined by the overall scheme.
In the recovery process control strategy, the pressure change in the recovery process should be changed steadily, if the energy absorbed by the damper is not considered, an ideal pressure and overcurrent area change curve is set according to the weight and speed of the unmanned aerial vehicle input during recovery, and in practice, the damper is designed at the front end of the system to absorb a part of kinetic energy, so that the valve opening during recovery can be further optimized by using a recovery overall simulation model.
According to the parameters determined by the overall scheme, parameters of the oil cylinder and the pulley are unchanged in the recovery process, the weight of the unmanned aerial vehicle is 400kg, the initial speed is 40m/s, the valve port diameter is gradually closed according to 30mm, the stroke of the damper is about 0.8m, the initial pressure of the accumulator is 1.5Mpa, the initial tension of the steel cable is 2000N, and the initial volume of the accumulator is 80L. From simulation results, according to the configuration of the throttle valve and the damper designed at present, the maximum acceleration in the recovery process is about 10g, the maximum cable tension is about 40KN, the maximum pressure of the oil cylinder in the recovery process is 13MPa, the displacement of the oil cylinder is about 2.4m, and the displacement of the damper is 0.8m. The simulation results are shown in fig. 16-18.
according to the results of overall parameter calculation and simulation technology, the maximum flow which needs to be improved when the unmanned aerial vehicle transmits exceeds 5000L/min, so that two high-frequency response cartridge valves with large diameters (DN 50) need to be selected, and the high-frequency response cartridge valves are controlled to be opened rapidly during transmitting, so that the energy released in the energy accumulator is discharged.
The total volume of the accumulators needed by the system is about 200L, and because a large amount of oil liquid is needed to be discharged in a very short time of emission, the maximum discharge flow of the bellows type accumulator is required, and according to the accumulator sample, the maximum discharge flow of the single 200L accumulator is about 1500L/min, so that the mode of combining a plurality of accumulators is required to meet the requirement of the maximum discharge. The maximum discharge flow of a single 20L accumulator is about 600L/min, and a mode of connecting 10 20L accumulators in parallel can be selected. The principle of the emission energy accumulator and the control valve group is shown in figure 19.
The energy accumulator assembly is selected to be 10 energy accumulators with the volume of 20 liters, and a parallel joint oil supply mode is adopted, so that the total volume of gas in the energy accumulator is 150 liters when the energy accumulator is to be launched, and the volume after the energy accumulator is launched is 177.7 liters. Namely:
initially, the following steps: p (P) 1 ＝15Mpa，V 1 ＝150(L)；
At the end, the method comprises the following steps:
V 2 ＝177.7(L)。
initial inflation pressure P 0 ＝0.9P 2 ＝10Mpa。
The main parameters of the energy accumulator are as follows:
nominal pressure: 31.5MPa;
nominal volume: 10X 20L;
form: an air bag type;
initial emission pressure: 15MPa.
The kinetic energy recovered by the unmanned aerial vehicle is mainly dissipated through a throttle valve, and part of the kinetic energy is charged into the energy accumulator group for storage.
The selected energy accumulator is a piston type energy accumulator with the volume of 80 liters, the total volume of gas in the energy accumulator is 80 liters when the energy accumulator is to be recovered, and the volume after the recovery is 52.3 liters. Namely:
initially, the following steps: p (P) 1 ＝1.5(Mpa)，V 1 ＝80(L)；
At the end, the method comprises the following steps:
V 2 ＝52.3(L)。
the recovery process mainly uses a throttling mode to absorb energy, and the initial opening area is calculated to be about:
the orifice diameter is about:
the main parameters of the recovery accumulator are as follows:
nominal pressure: 10MPa;
initial pressure: 1.5MPa
Maximum working pressure: 3MPa;
volume: 80L;
form: and a piston.
The present invention is not limited to the above embodiments, and those skilled in the art can implement the present invention in various other embodiments according to the examples and the disclosure of the drawings, so that the design of the present invention is simply changed or modified while adopting the design structure and concept of the present invention, and the present invention falls within the scope of protection.
Claims (6)
1. The design method of the unmanned aerial vehicle integrated emission recovery system is characterized by comprising the following steps of:
step 1, designing an unmanned aerial vehicle integrated emission recovery system structure;
step 2, designing a process of unmanned aerial vehicle emission and recovery and determining parameters;
step 3, designing a control strategy of the energy accumulator in the process of emission and recovery of the unmanned aerial vehicle;
step 4, designing the energy accumulator according to a control strategy of the energy accumulator;
in step 1, the unmanned aerial vehicle integrated emission recovery system comprises an energy absorption and release module, a guide rail module and a driving cable module;
the energy absorbing and releasing module comprises a hydraulic cylinder, a movable fixed pulley block and an energy accumulator; the hydraulic cylinder adopts a double-acting oil cylinder, the hydraulic cylinder comprises an oil cylinder piston rod, the end part of the oil cylinder piston rod is connected with the movable fixed pulley block, and the hydraulic cylinder is provided with an oil emission port and an oil recovery port; the movable fixed pulley block comprises a movable pulley block and a fixed pulley block; the movable pulley block 2 comprises a pulley seat and a plurality of parallel and coaxial pulleys, and the pulley seat is fixedly connected with the head of the cylinder piston rod; the fixed pulley block 3 consists of a plurality of parallel and coaxial pulleys, and the fixed pulley block 3 is fixedly connected with the ground; the energy accumulator comprises a transmitting energy accumulator and a recovery energy accumulator, the transmitting oil port is connected with the transmitting energy accumulator, and the recovery oil port is connected with the recovery energy accumulator;
the driving cable module comprises a steel cable, one end of the steel cable is connected with the guide rail module, and the other end of the steel cable is connected with the energy absorbing and releasing module;
the guide rail module comprises a guide rail, a sliding block, a transmitting frame, a recovery rope and a pulley net; the guide rail is fixedly arranged, the sliding block is matched with the guide rail and can move along the guide rail, one end of the sliding block is rigidly connected with the steel cable, and the sliding block is connected to the hydraulic cylinder through the movable fixed pulley block; the launching frame, the recovery rope and the pulley net are connected with the sliding block. Wherein the recovery cable and the pulley net are connected with the slider only in the recovery state, and the launching cradle is mounted with the slider only in the launching state.
2. The unmanned aerial vehicle integrated launch recovery system of claim 1, wherein in step 1, the drive cable module comprises a recovery damper comprising a movable sheave, a damper, a first guide sheave, and a second guide sheave; the first guide pulley and the second guide pulley are fixedly arranged, the shaft of the movable pulley is connected with the damper, and the steel cable sequentially bypasses the first guide pulley, the movable pulley and the second guide pulley.
3. The unmanned aerial vehicle integrated launching and recovery system of claim 1, wherein in step 2, the unmanned aerial vehicle integrated launching and recovery system determines the launching weight m and the launching speed v of the unmanned aerial vehicle, and the guide rail working stroke s and the initial launching cradle traction trolley mass are m 1 The average emission thrust is:
F average of ＝(m+m 1 )a
Wherein, addSpeed of speed
s is the rail working stroke, m is the emission weight of the unmanned aerial vehicle, m 1 The weight of the traction trolley is as the weight of the traction trolley;
meanwhile, when the transmission and the recovery are considered, the penetrating and winding ratio of the movable fixed pulley block is 1: z;
the main parameters of the hydraulic system are calculated as follows:
maximum speed reached by the piston rod:
working stroke of the hydraulic cylinder:
the diameter D of the inner cavity of the hydraulic cylinder is initially determined, the diameter D of the piston rod is determined, and the effective area of the rod cavity of the hydraulic cylinder is
/>
The hydraulic cylinder has the maximum flow rate that the pole chamber reaches: q (Q) With rod cavities ＝S Effective and effective ·V Cylinder with a cylinder body ；
The volume of oil required in the launching process is as follows:
ΔV＝S effective and effective ·L Cylinder with a cylinder body
Effective area of hydraulic cylinder rodless cavity:
the maximum flow rate reached by the rodless cavity of the hydraulic cylinder is as follows: q (Q) Rodless cavity ＝S Rodless ·V Cylinder with a cylinder body ；
The average pressure required by the rod cavity during the hydraulic cylinder emission is as follows:
initially setting the total volume of gas in the accumulator to be V when the accumulator is to be launched 1 The volume after emission is V 2 The method comprises the steps of carrying out a first treatment on the surface of the Namely:
initially, the following steps:
wherein ：P1 To the pressure of the accumulator during firing, P 0 For initial pressure of accumulator, V 0 N is the adiabatic bar index, which is the initial volume of the accumulator;
at the end, the method comprises the following steps:
4. the unmanned aerial vehicle integrated launch and recovery system of claim 3, wherein in step 2, the recovery process is checked and calculated using launch parameters, and the determined launch and recovery process overall parameters include rail effective length, wire rope system draw-in ratio, hydraulic cylinder maximum travel, hydraulic cylinder inner diameter, piston rod diameter, hydraulic cylinder maximum operating pressure, and accumulator volume.
5. The integrated launch and recovery system of claim 4, wherein in step 3, for the launch process, models of moving components such as pulleys, cables, accumulators, cylinders and the like are respectively built, and the transmission ratio at the movable pulleys and the accumulator-cylinder model are designed according to a system schematic diagram, and the specific calculation model of each subsystem comprises:
the pulley system, assuming clockwise rotation is positive, can be equivalently:
(F i+1 -F i -F fi )R＝Jα
wherein ：Fi+1 Tension for the i+1st section of rope; f (F) i Tension for the i-th rope;
r is the radius of the pulley; j is the rotational inertia of the pulley assembly; alpha is the angular acceleration of the pulley assembly;
wherein, pulley assembly rotating member is approximately ring plane board, and its moment of inertia J can be expressed as:
the relationship between the angular acceleration α and the linear acceleration a is: a=αr;
wherein: m is the weight of the pulley assembly revolution body, R is the diameter of the outer circle, and R is the diameter of the inner circle;
wherein ,
can be considered as equivalent mass of a single sheave assembly;
according to hooke's law, any piece of rope tension is calculated:
e is the elastic modulus of the rope; a is the effective cross-sectional area of the rope; Δl is the elastic elongation of the rope; l is the length of the rope;
the amount of deformation for the segment 1 rope can be expressed as:
ΔL＝S i -S f
the amount of deformation for the 2 nd-6 th rope can be expressed as:
ΔL＝S g +S i+1 -S i
S g for the displacement of the oil cylinder S i+1 Is the rotation quantity of the (i+1) th pulley, S i Is the rotation amount of the ith pulley;
according to calculation of a hydraulic system, according to the working process of the hydraulic system, the emission instant control flow control valve is opened, high-pressure oil in the energy accumulator enters the oil cylinder to push the oil cylinder to retract rapidly, and further the aircraft is driven to accelerate, and because the emission process is faster (less than 1 s), remarkable heat exchange with the outside is not carried out, and the process can be realizedTo be regarded as an adiabatic process in which 3 state quantities of the gas P, V, T are simultaneously changed, wherein the adiabatic process between P, V is PV 1. ＝ 0 V 0 1. The pressure change during the firing process can be calculated from the volume change, and the pressure change in the accumulator satisfies the following equation:
wherein ：P1 Is the pressure of the accumulator during firing; p (P) 0 Is the initial pressure of the accumulator; v (V) 0 Is the initial volume of the accumulator;
V 1 the volume of oil entering the oil cylinder;
the accumulator enters the oil cylinder through the large-flow control valve, a certain throttling pressure difference is generated when the flow control valve is opened, and the pressure in the oil cylinder can be obtained according to a flow equation to meet the following formula:
wherein ρ is the oil density, Q is the flow, C d Is the flow coefficient, A o Is the area of the overcurrent;
the flow Q can be expressed as:
Q＝AV g
the movement of the piston cylinder meets the following conditions:
V g ＝a g dt
wherein ,ag Is the acceleration of the moving part of the oil cylinder,
m is the sum of the rope tensions acting on the cylinders f The weight of the oil cylinder moving part;
F g ＝P 1 A
wherein A is the effective area of the oil cylinder moving part;
and (3) calculating the unmanned aerial vehicle, wherein for the emission of the unmanned aerial vehicle, the motion process of the unmanned aerial vehicle meets the following formula:
V f ＝a f ×dt
a f ＝(F 1 -F f )/M f
wherein ,Vf Is the speed of the unmanned aerial vehicle, a f Acceleration of unmanned plane, F f Resistance, M, applied to unmanned aerial vehicle in motion process f For unmanned aerial vehicle weight, F 1 Is the rope tension to which the unmanned aerial vehicle is subjected.
6. The unmanned aerial vehicle integrated launching and recovery system of claim 5, wherein in step 3, the model of the recovery process also mainly comprises a pulley system, a hydraulic system and an unmanned aerial vehicle, and for the pulley system, the pulley system calculation model is basically consistent with the launching, and the motion model of the pulley is as follows:
the amount of deformation of the rope, as opposed to the firing process, can be expressed as:
ΔL＝S f -S i
the amount of deformation for the 2 nd-6 th rope can be expressed as:
ΔL＝S i -S i+1 -S g
wherein ,Sg For the displacement of the oil cylinder S i+1 Is the rotation quantity of the (i+1) th pulley, S i Is the rotation amount of the ith pulley;
equation of motion for unmanned aerial vehicle:
a f ＝(-F 1 -F f )/M f
calculation of hydraulic systems
The motion equation of the oil cylinder motion piece is as follows:
V g ＝a g dt
for hydraulic force F g ＝P 1A, wherein P1 Is the cylinder pressure, the cylinder pressure P 1 Can be expressed as:
P 1 ＝P 0 +ΔP
wherein ,P0 As accumulator pressure, ΔP is throttle differential pressure;
wherein ρ is the oil density, Q is the flow, C d Is the flow coefficient, A o Is the area of the overcurrent.
The flow Q can be expressed as:
Q＝AV g
wherein ,P0 For accumulator pressure, this can be expressed as:
wherein ,V0 For the initial volume of the accumulator, V 1 For volume change of accumulator, V 1 ＝S g A。
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