CN104503457B - Turning anti-collision control method for UAV formation flight - Google Patents

Abstract

The anti-collision control method for UAV formation flight turning according to the present invention adopts a method based on route restriction for the isomorphic leader wingman type diamond formation, and controls the turn of the leader according to the maneuverability limitation of the UAV. The route is corrected, and the wingmen change their respective routes according to the relative position of the lead plane, and generate an actual flyable formation turning route. The formation tracking error is reduced by adopting the anti-collision method of the invention, the destruction of the formation structure is avoided, and the anti-collision problem when the formation turns is solved in route planning.

Description

Anti-collision control method for UAV formation flight turning

technical field

The invention relates to an anti-collision control method for UAV formation flight turning, in particular to a UAV formation turning route restriction method, which belongs to the field of route planning.

Background technique

In addition to the mobility and agility of UAVs, the development of modern UAVs also requires UAVs to have the ability of multi-machine cooperative flight and combat. UAV formation flight is to arrange multiple UAVs with autonomous functions in a three-dimensional space according to a certain structural form to ensure the stability of the formation during the flight process, but it can be dynamically adjusted according to changes in external conditions and mission requirements. . The success rate of UAV formation missions and the ability to resist emergencies are much higher than those of single flight, and the short-distance formation can effectively increase the aerodynamic performance of UAVs in the following position and save fuel.

The formation maintenance of UAV formation flight is particularly important when turning. Most of the current route planning algorithms do not fully consider the maneuverability limitations of UAVs, especially the speed limit. If the flight speed cannot be reduced to the theoretical design value specified by the route, it will easily collide with the outside UAV, and when the formation transitions from straight flight to turning flight, due to the switching of the control law, it is easy to cause the system to malfunction. Stability, thereby increasing the probability of collision accidents when turning.

Aiming at the above-mentioned turning anti-collision problem of UAV formation flight, the present invention designs a turning anti-collision control method based on route restriction. According to the maneuverability limit of the UAV, the route is corrected and restricted to ensure that the turning route of the formation is strictly achievable, so as to avoid collisions caused by improper route planning.

Contents of the invention

Technical problems to be solved:

The purpose of the present invention is to provide a UAV formation flying turning anti-collision control method. According to the maneuverability limitation of the UAV, the route is corrected and restricted, thereby avoiding the collision phenomenon caused by improper route planning.

Technical solutions:

In order to realize the above functions, the present invention provides a UAV formation flight turning anti-collision control method, characterized in that: the method is realized by the following steps:

Step 1. Calculate the maneuverability limit of the UAV, that is, the relative maximum speed and the relative minimum speed; set an overshoot σ to obtain the following formula,

In the formula, *v _min and *v _max are actual minimum speed and actual maximum speed, v _min and v _max are relative minimum speed and relative maximum speed, and V ₀ is the flight speed of the formation before turning;

Step 2, combined with the formation formation, calculate the wingman with the largest turning radius and the smallest turning radius when turning, and adjust the turning radius of the lead plane according to its relative maximum speed and relative minimum speed limit;

Step 3: According to the adjusted turn radius of the lead aircraft, the turning radius of each wingman is generated through the change of formation configuration position relationship, and the final formation turning route is obtained.

Further, in step 2, the formation formation is set as four isomorphic UAVs, A is the leader, and B, C, and D are the wingmen, forming a diamond-shaped formation of the lead wingman.

Further, the formation of the leader wingman diamond formation is specifically divided into three configurations according to the distance relationship between the drones, and the distance between A and B is set as 1, B and D The distance between A and C is recorded as 2l ₁ , the distance between A and C is recorded as 2l ₂ , and the three configurations are:

Rhombus configuration 1 is l=2l ₂ , rhombus configuration 2 is l>2l ₂ , rhombus configuration 3 is l<2l ₂ .

Further, in the step 1, according to the actual speed control system, it is designed to be underdamped and track the situation of overshoot, so the overshoot of σ=20% is introduced into the calculation of the actual maximum and minimum speed to obtain Relative maximum and minimum speed:

Further, the specific method for adjusting the turning radius of the lead aircraft in step 2 is:

Suppose R _L and V _L are the turning radius and speed of lead plane A, r _B and V _B are the turning radius and speed of wingman B, r _C and V _C are the turning radius and speed of wingman C, r _D and V _D are The turning radius and speed of wingman D, in order to ensure that the configuration of the formation remains unchanged, the following formula holds:

V _L /R _L ＝V _B /r _B ＝V _C /r _C ＝V _D /r _D (1)

Suppose the minimum turning radius of each wingman is r _S , and the corresponding speed is V _S ; the maximum turning radius is r _M , and the corresponding speed is V _M ; then V _S must meet the minimum speed v _min limit of the UAV, and V _M is to satisfy the maximum velocity v _max limit of the UAV, i.e.,

V _S ＝(V _L /R _L )r _S ≥v _min (2)

V _M ＝(V _L /R _L )r _M ≤v _max (3)

According to the specific three rhombus configurations, firstly determine the corresponding minimum turning radius r _S and maximum turning radius r _M , and then substitute (2) and (3) respectively to obtain the two constraint inequalities about _RL , and solve The inequality obtains the minimum value of R _L that satisfies the constraints, and takes it as the corrected turning radius of lead aircraft A.

Further, the turning radius of each wingman is determined according to the adjusted turning radius of the lead plane, and the final formation turning route is obtained. The turning radius of each wingman is as follows:

In the formula, r _B , r _C , and r _D are the turning radii of wingman B, C, and D respectively, and the included angle between wingman B, D and lead aircraft A is 2φ, α=π/2-φ.

Beneficial effect:

A UAV formation flight turning anti-collision control method according to the present invention adopts a method based on route restrictions for the isomorphic leader wingman diamond formation. To make corrections, the wingmen change their respective routes according to the relative position of the lead plane, and generate an actual flyable formation turning route. The maneuverability and parameters of the leader and wingman in the isomorphic diamond formation of the leader and wingman are the same, which is a common formation in the UAV formation. The maneuverability limit of the drone refers to the relative maximum and minimum speed limits of the drone, and the relative maximum and minimum speed limits are calculated based on the actual maximum and minimum speeds considering the oscillation of the actual speed control. Formation tracking error is reduced, formation structure damage is avoided, and the problem of anti-collision when formation turns is solved in route planning.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is further described:

Fig. 1 is the relative minimum and maximum speed schematic diagram of unmanned aerial vehicle described in the present invention;

Fig. 2 is a kind of isomorphic leader wingman type diamond formation formation of the present invention;

Fig. 3 is a schematic diagram of a UAV formation leader turning left in a rhombus configuration;

Fig. 4 is a schematic diagram of the UAV formation leader turning left under the diamond configuration II;

Fig. 5 is a schematic diagram of the UAV formation leader turning left in the rhombic configuration three times;

Fig. 6 is the UAV formation turning route diagram that does not adopt the route restriction method of the present invention;

Fig. 7 is a curve diagram of tracking error when the unmanned aerial vehicle formation turns without adopting the route restriction method of the present invention;

Fig. 8 is a UAV formation turning route diagram using the route restriction method of the present invention;

Fig. 9 is a curve diagram of tracking error when UAV formation turns using the route limitation method of the present invention.

detailed description

The present invention provides a UAV formation flying turning anti-collision control method. In order to make the object, technical solution and effect of the present invention clearer and clearer, the present invention will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific implementations described here are only used to explain the present invention, not to limit the present invention.

Adopt the UAV formation flight turning anti-collision control method of the present invention, specifically follow the following steps.

Step 1. Calculate the maneuverability limit of the UAV, that is, the relative maximum and minimum speed. Considering that the actual speed control system is generally designed in the form of underdamping, and there is an overshoot in the tracking, so adding σ=20% overshoot to the limit of the actual maximum and minimum speed results in a relative maximum and minimum speed. As shown in Figure 1, the following formula is obtained,

In the formula, *v _min and *v _max are the actual minimum and maximum speeds, v _min and v _max are the relative minimum and maximum speeds, and V ₀ is the flight speed of the formation before entering the turn.

Step 2. Combined with the formation formation, calculate the wingman with the largest and smallest turning radius when turning, and adjust the turning radius of the lead plane according to its relative maximum and minimum speed limits.

In the planar rhombus formation formed by four UAVs shown in Figure 2, UAV A is the leader, and B, C, and D are the wingmen. The distance between A and B is recorded as l, the distance between B and D is recorded as 2l ₁ , the distance between A and C is recorded as 2l ₂ , and the angle between B, D and the lead aircraft is 2φ. When the lead plane is making a turning maneuver, take the lead plane turning left as an example (as shown in Figure 3), in order to keep the formation configuration unchanged, the speed of the wingman within the turning radius should be lower than the speed of the lead plane, while in the turn The speed of the wingman outside the radius is greater than the speed of the lead plane. In order to meet the minimum and maximum speed limits of the UAV, the turning radius of the lead aircraft must be limited. Suppose the flight speed of the lead plane is V _L , the turning radius is R _L , r _B , V _B are the turning radius and speed of wingman B, r _C , V _C are the turning radius and speed of wingman C, r _D , V _D are Wingman D's turning radius and speed. In order to ensure that the configuration of the formation remains unchanged, the following formula holds:

V _L /R _L ＝V _B /r _B ＝V _C /r _C ＝V _D /r _D (1)

Suppose the minimum turning radius among each wingman is r _S , and the corresponding speed is V _S ; the maximum turning radius is r _M , and the corresponding speed is V _M . Then V _S must meet the minimum speed v _min limit of the drone, and V _M must meet the maximum speed v _max limit of the drone, that is,

V _S ＝(V _L /R _L )r _S ≥v _min (2)

V _M ＝(V _L /R _L )r _M ≤v _max (3)

According to the size relationship of l, l ₁ and l ₂ , consider the three rhombus formations shown in Fig. 3 to Fig. 5: the rhombus configuration shown in Fig. 3 corresponds to l = 2l ₂ , the rhombus configuration shown in Fig. 4 Type II corresponds to l>2l ₂ , and rhombus configuration III shown in Figure 5 corresponds to l<2l ₂ .

(1) l=2l ₂ formation formation

In the formation formation in Figure 3, r _B <r _C <r _D , that is, r _S =r _B , r _M =r _D .

α=π/2-φ (6)

Substituting (4) into (2), we can get

Similarly, substituting formula (5) into formula (3), we can get

make

In order to satisfy formulas (7) and (8), the minimum turning radius of the lead aircraft is:

If sin α>v _min /V _L , then R _min =R ₂ ;

Otherwise R _min =max(R ₁ , R ₂ ).

(2) l＞2l ₂ formation formation

In the formation formation of Figure 4, the line EF is the perpendicular bisector of the rhombus side BC. Note that the length of line segment AE is

when , there is r _C <r _B <r _D .

α=π/2-φ (12)

Substituting (10) into (2), we can get

Similarly, substituting (11) into (3), we can get

It can be seen that formula (13) is always established, so only formula (14) needs to be satisfied.

make Then the minimum turning radius of the lead aircraft is: R _min = R ₂ .

when When r _B <r _C <r _D , the solution steps and results are exactly the same as l=2l ₂ , that is, the minimum turning radius of the leader is:

If sin α>v _min /V _L , then R _min =R ₂ ;

Otherwise R _min =max(R ₁ , R ₂ ).

in,

It should be noted that in case, the adjusted _RL may appear In the case of , at this time, it is necessary to _perform another Under the circumstances of the adjustment, get the final revised _RL value.

(3) l<2l ₂ formation formation

In the formation formation of Figure 5, the line EF is the perpendicular bisector of the rhombus side CD. Note that the length of line segment AE is

when (the turning center is shown as O ₁ in Figure 5), r _B <r _D <r _C .

α=π/2-φ (18)

Substituting formula (16) into formula (2), we can get

Similarly, substituting (17) into (3), we can get

make

In order to satisfy formulas (19) and (20), the minimum turning radius of the lead aircraft is:

If sin α>v _min /V _L , then R _min =R ₂ ;

Otherwise R _min =max(R ₁ , R ₂ ).

when (the turning center is shown as O ₂ in Fig. 5), r _B <r _C <r _D , the solution steps and results are exactly the same as in the case of l=2l ₂ , that is, the minimum turning radius of the lead aircraft is:

If sin α>v _min /V _L , then R _min =R ₂ ;

Otherwise R _min =max(R ₁ , R ₂ ).

in,

It should be noted that in case, the adjusted _RL may appear In the case of , at this time, it is necessary to _perform another Under the circumstances of the adjustment, get the final revised _RL value.

Step 3. Determine the turning radius of each wingman according to the adjusted turning radius of the lead plane, and generate the formation turning route. The turning radius of each wingman is as follows:

In order to verify the effectiveness of the present invention in UAV formation flight turning anti-collision, the following simulation experiments are carried out. The simulation tool uses MATLAB/Simulink software. The formation adopts the rhombus configuration shown in Figure 4, and the values of each parameter are: φ=75°, l=400m, l ₁ =386m, l ₂ =103m, *v _max =400m/s, *v _min =130m/ s. Suppose the lead aircraft turns at the coordinates (0m, 0m), the turning speed is V _L =V ₀ =200m/s ² , the centripetal acceleration a _L =40m/s ² , and the turning radius R _L =1000m. It can be calculated that the relative maximum and minimum speeds are v _max =367m/s and v _min =142m/s respectively.

From formula (1), it can be calculated that wingman B's theoretical speed V _B =124m/s, wingman C's theoretical speed V _C =204m/s, wingman D's theoretical speed V _D =278m/s. It can be seen that V _B does not meet the minimum speed limit, and the speed limit is added to the formation control structure, and then the simulation experiment is carried out. The experimental results are shown in Figure 6 and Figure 7. The formation distance cannot be maintained and the formation structure is destroyed.

Using the route restriction method of the present invention, it can be calculated thus corresponding to situation is corrected.

Correct the turning radius of the lead plane to R _min =R ₁ =1312m, calculate the theoretical speed of wingman B again V _B =142m/s, the theoretical speed of wingman C V _C =202m/s, and the theoretical speed of wingman D V _D = 259m/s. The simulation experiment is carried out, and the experimental results are shown in Figure 8 and Figure 9. Comparing Figure 7 and Figure 9, it can be seen that after limiting the turning radius of the lead aircraft, the formation tracking error is reduced, and the formation structure is avoided. Solved the anti-collision problem when turning in formation.

It can be understood that those skilled in the art can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention, and all these changes or replacements should belong to the protection scope of the appended claims of the present invention.

Claims (6)

1. The unmanned aerial vehicle formation flight turning collision prevention control method is characterized by comprising the following steps: the method is realized by the following steps:

step 1, calculating the maneuvering performance limits of the unmanned aerial vehicle, namely the relative maximum speed and the relative minimum speed; an overshoot sigma is set to obtain the following formula,

$\frac{v_{min}-{v_{*}}_{\min }}{V_0-v_{\min }}=\mathrm{\&sigma;},\frac{{v_{*}}_{max}-v_{max}}{v_{max}-V_0}=\mathrm{\&sigma;};$

in the formula,^*v_min、^*v_maxis the actual minimum velocity, the actual maximum velocity, v_min、v_maxIs a relative minimum speed, a relative maximum speed, V₀Is the flight speed of the formation before entering a turn;

step 2, combining the formation, calculating a wing plane with the largest turning radius and the smallest turning radius when turning, and adjusting the turning radius of a long plane according to the relative maximum speed and the relative minimum speed limit;

and 3, generating the turning radius of each wing plane through the change of the formation configuration position relationship according to the adjusted turning radius of the long plane to obtain the final formation turning fairway.

2. The unmanned aerial vehicle formation flight turning collision prevention control method according to claim 1, characterized in that: the formation in step 2 is set to four isomorphic unmanned planes, a is a captain, B, C, D is a bureaucratic, forming a bureaucratic-type diamond formation.

3. The unmanned aerial vehicle formation flight turning collision prevention control method according to claim 2, characterized in that: the formation of the rhombus formation of the bureaucratic plane type is divided into three configurations according to the distance relationship between the unmanned aerial vehicles, the distance between A and B is set as l, and the distance between B and D is set as 2l₁And the distance between A and C is 2l₂The three configurations are:

rhomboid configuration I is l-2 l₂The diamond configuration two is that l is more than 2l₂The rhombus configuration III is that l is less than 2l₂。

4. The unmanned aerial vehicle formation flight turning collision prevention control method according to any one of claims 1 to 3, characterized in that: in step 1, the actual speed control system is designed into an underdamping mode, and the overshoot is tracked, so that the overshoot with the sigma of 20% is introduced into the calculation of the actual maximum speed and the actual minimum speed to obtain the relative maximum speed and the relative minimum speed:

$\frac{v_{min}-{v_{*}}_{min}}{V_0-v_{min}}=20\%,\frac{{v_{*}}_{max}-v_{max}}{v_{max}-V_0}=20\%---\left(4\right).$

5. the unmanned aerial vehicle formation flight turning collision prevention control method according to claim 4, characterized in that: the specific method for adjusting the turning radius of the long crane in the step 2 comprises the following steps:

let R_L、V_LIs the turning radius and speed, r, of the longator A_B、V_BRadius of turning and speed, r, of a wing plane B_C、V_CRadius of turning and speed, r, of a wing plane C_D、V_DThe turning radius and the speed of the wing machines D, in order to guarantee the configuration of the formation unchanged, the following holds:

V_L/R_L＝V_B/r_B＝V_C/r_C＝V_D/r_D(1) let the minimum turning radius in each wing plane be r_SCorresponding to a velocity V_S(ii) a Most preferablyLarge turning radius r_MCorresponding to a velocity V_M(ii) a Then V_SMinimum velocity v to satisfy unmanned aerial vehicle_minLimitation, V_MMaximum speed v to satisfy unmanned aerial vehicle_maxThe number of the limits, that is,

V_S＝(V_L/R_L)r_S≥v_min(2)

V_M＝(V_L/R_L)r_M≤v_max(3)

according to the concrete three diamond configurations, firstly determining the corresponding minimum turning radius as r_SAnd a maximum turning radius of r_MThen substituting the obtained values into the expressions (2) and (3) to obtain the value of R_LSolving the inequality to obtain R satisfying the constraint condition_LAnd the minimum value of (3) is set as the turning radius of the tractor a after correction.

6. The unmanned aerial vehicle formation flight turning collision prevention control method according to claim 5, characterized in that: determining the turning radius of each wing plane according to the adjusted turning radius of the lead plane to obtain a final formation turning route, wherein the turning radius of each wing plane is as follows:

$r_B^2=R_L^2+l^2-2R_{L}lcos\mathrm{\&alpha;}---\left(5\right)$

$r_C^2=R_L^2+{\left(2l_2\right)}^2-4R_L{l}_{2}cos(\mathrm{\&alpha;}+\mathrm{\&phi;})---\left(6\right)$

$r_D^2=R_L^2+l^2-2R_{L}lcos(\mathrm{\&alpha;}+2\mathrm{\&phi;})---\left(7\right)$

in the formula, r_B、r_C、r_DThe respective turning radius of the wing-planes B, C, D, the wing-planes B, D, have an angle of 2 phi with the long-plane a, α pi/2-phi.