A compliant continuous variable structure control method under the condition of servo loop frame limiting

Abstract

A compliant continuous variable structure control method under the condition of a servo loop frame limiting condition, comprising: obtaining the angular velocity of a table body on an X p axis, Y p axis and Z p axis according to the angular velocity output by a gyroscope mounted on the table body and obtaining the angle and angular velocity of internal relative rotation of a four-axis inertial stabilization platform system; calculating the resultant rotation angular velocity ω p of the table body on the Z z axis, the resultant rotation angular velocity ω p1 of an inner frame on the Y y axis, the resultant rotation angular velocity ω p2 of a middle frame on the X x axis and the resultant rotation angular velocity ω p3 of an outer frame on the Y yk′ axis according to the angular velocity component and the angle of internal relative rotation; the present application can ensure that the platform table body is stabilized relative to the inertial space and has the advantages of full attitude and high precision.

Description

TECHNICAL FIELD

[0001] The application relates to a compliant continuous variable structure control method under a frame limiting condition of a four-axis inertial stabilization platform servo loop, and belongs to the technical field of inertial measurement. BACKGROUND

[0002] Since a three-axis inertial platform system has a frame locking phenomenon, it is difficult to meet the requirements of large maneuvering motion of a carrier, therefore, a four-axis inertial platform system is generated. The four-axis inertial platform system increases an outer frame on the basis of a platform body, an inner frame and a middle frame relative to the three-axis inertial platform system, and the outer frame is between the middle frame and a base.

[0003] In engineering applications, in order to stabilize the platform body relative to an inertial space, a limiting stopper is installed on an inner frame shaft to limit the range of the inner frame angle (generally not more than ±45°). When beta xk = ±90°, the inner frame angle will change with the motion of the carrier and cannot be kept at zero. A solution is as follows: a method of rotating the outer frame by 90° to make the inner frame angle return to the vicinity of zero, and simultaneously making the middle frame deviate from the ±90° position, so that the three-frame four-axis platform re-meets the working conditions of the traditional servo loop, refer to the document "Four-axis inertial platform servo frame control strategy research, Navigation and Control, 2017, No. 4".

[0004] When the method is adopted, the inner frame angle and the middle frame angle are in different intervals, and there is switching between different control signals when the partition control is adopted, but the switching moment will also cause instantaneous jitter of the platform body, resulting in shaking of the platform body relative to the space. SUMMARY

[0005] The technical problem to be solved by the application is to overcome the shortcomings of the prior art and solve the stable control problem of the four-axis inertial stabilization platform servo loop under the frame limiting condition.

[0006] The application is achieved by the following technical scheme:

[0007] A compliant continuous variable structure control method of a four-axis inertial stabilization platform servo loop under a frame limiting condition, for inner frame limiting, the control method comprises the following steps:

[0008] According to the angular velocity output by the gyroscope installed on the platform body, the angular velocity components of the platform body on the X p axis, the Y p axis and the Z p axis are obtained

[0009] The angle beta p2 of the outer frame rotating around the X xkThe inner frame rotates around the Y axis of the inner frame body coordinate system p1 The angle β of the shaft rotation yk The inner frame rotates around the Z axis of the table body coordinate system p The angle β of the shaft rotation zk ;

[0010] Given the value of the compliant variable structure parameter k, the angular velocity correction value of the compliant variable structure is calculated:

[0011]

[0012] Where, the interval parameters β ny , β my are the minimum and maximum values of β yk , respectively;

[0013] According to the measured β xk , β yk , β zk , and and the angular velocity correction value Δω, the rotation angular velocities of the table body, the inner frame, the middle frame and the outer frame are calculated, and the specific calculation formula is as follows:

[0014]

[0015] Where, ω z is the combined rotation angular velocity of the table body Z p axis; ω y is the combined rotation angular velocity of the inner frame Y p1 axis; ω x is the combined rotation angular velocity of the middle frame X p2 axis; ω yk′ is the combined rotation angular velocity of the outer frame Y p3 axis;

[0016] ω z , ω y , ω x and ω yk′ are output to the linear controller and then act on the torque motors at the ends of the four-axis platform to realize the stability of the table body relative to the inertial space.

[0017] A compliant continuous variable structure control method for a four-axis inertially stabilized platform servo loop under frame limiting conditions, for the middle frame limiting, the control method comprises:

[0018] According to the angular velocity output by the gyroscope installed on the table body, the angular velocity components of the table body on the X p axis, Y p axis and Z p axis are obtained

[0019] The measured outer frame rotates around the middle frame body coordinate system X p2 The angle β of the axis rotation xk The middle frame rotates around the inner frame body coordinate system Y p1 The angle β of the axis rotation yk The inner frame rotates around the table body coordinate system Z p The angle β of the axis rotation zk ;

[0020] Given the value of the compliant variable structure parameter k, the angular velocity correction value of the compliant variable structure is calculated:

[0021]

[0022] Where, the interval parameter β nx , β mx is the minimum and maximum value of β xk respectively;

[0023] According to the measured β xk , β yk , β zk , and and the angular velocity correction value Δω, the rotation angular velocity of the table body, the inner frame, the middle frame and the outer frame is calculated, and the specific calculation formula is as follows:

[0024]

[0025] Where, ω z is the combined rotation angular velocity of the table body Z p axis; ω y is the combined rotation angular velocity of the inner frame Y p1 axis; ω x is the combined rotation angular velocity of the middle frame X p2 axis; ω yk′ is the combined rotation angular velocity of the outer frame Y p3 axis;

[0026] ω z , ω y , ω x and ω yk′ are output to the linear controller and then act on the four-axis platform axis torque motor to realize the stability of the table body relative to the inertial space.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] (1) the servo loop inner frame or the middle frame limiting time flexible continuous variable structure control method given by the application overcomes the influence of the transition process of the interval discrete variable structure control on the stability of the table body in the interval switching process, eliminates the dynamic error caused by the frequent shaking caused by the interval switching, and improves the precision of the inertial navigation;

[0029] (2) the servo loop inner frame or the middle frame limiting time flexible continuous variable structure control method given by the application has the characteristics of smaller output energy than the inner frame limiting time interval variable structure control method, which is beneficial to saving control energy.

[0030] (3) the four-axis inertial stabilized platform system described in the application has the characteristics of small overshoot relative to the inner frame limiting time interval variable structure control method, and does not need to be divided into intervals, the control algorithm is simple, and easy to implement in engineering; BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the relationship between the five body coordinate systems in the four-axis inertial stabilized platform system of the application;

[0032] Figure 2 is the step flow chart of the servo loop inner frame or the middle frame limiting time flexible continuous variable structure control method of the four-axis inertial stabilized platform system of the application;

[0033] Figure 3 is the region divided according to the inner frame angle and the middle frame angle in variable structure partition control;

[0034] Figure 4 is the change process of the frame angle with time in variable structure partition control;

[0035] Figure 5 is the region where the inner frame and the middle frame angle are located in variable structure partition control;

[0036] Figure 6 is the change process of the table body angular velocity with time in variable structure partition control;

[0037] Figure 7 is the change process of the table body angle relative to the inertial space with time in variable structure partition control;

[0038] Figure 8 is the change process of the frame angle with time in the inner frame limiting time flexible continuous variable structure control of the first embodiment;

[0039] Figure 9 is the region where the inner frame and the middle frame angle are located in the inner frame limiting time flexible continuous variable structure control of the first embodiment;

[0040] Figure 10The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0041] Figure 11 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0042] Figure 12 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0043] Figure 13 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0044] Figure 14 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0045] Figure 15 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0046] Figure 16 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0047] Figure 17 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0048] Figure 18 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0049] Figure 19 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0050] Figure 20 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0051] Figure 21 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0052] Figure 22 The variation of the angular velocity of the platform with time for the compliant continuous variable structure control when the inner frame is limited in the first embodiment;

[0053] Figure 23 This describes the change in the angle of the platform relative to the inertial space over time when using the compliant continuous variable structure control with frame limiting in Implementation Method 2.

[0054] Figure 24 This describes the change of the frame angle over time when using the compliant continuous variable structure control with frame limiting in Implementation Method 2.

[0055] Figure 25 This refers to the area where the angles of the inner and middle frames are located when using the compliant continuous variable structure control with frame limiting in Implementation Method 2.

[0056] Figure 26 This describes the change in the angular velocity of the platform over time when using the compliant continuous variable structure control with frame limiting in Implementation Method 2.

[0057] Figure 27 This describes the change in the angle of the platform relative to the inertial space over time when using the compliant continuous variable structure control with frame limiting in Implementation Method 2. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0059] Implementation Method 1:

[0060] The compliant continuous variable structure control method for the inner frame limit of the servo loop of the four-axis inertial stabilization platform provided in this embodiment is implemented based on a four-axis inertial stabilization platform system. This four-axis stabilization platform system includes a base, an outer frame, a middle frame, an inner frame, and a platform body. The corresponding body coordinate systems are the base body coordinate system X1Y1Z1 and the outer frame coordinate system X... p3 Y p3 Z p3 , Medium frame body coordinate system X p2 Y p2 Z p2 The inner frame body coordinate system X p1 Y p1 Z p1 and the X coordinate system of the platform body p Y p Z p .

[0061] like Figure 1 The diagram shows the relationship between the five coordinate systems. The origins of these five coordinate systems coincide, and they have the following relative constraints: the Z-axis of the platform body coordinate system... p Z-axis and the coordinate system of the inner frame p1 The axes coincide, and the Y-axis of the body coordinate system of the middle frame is... p2 Y-axis and the coordinate system of the inner framep1 The axes coincide, and the X coordinate of the outer frame body coordinate system is... p3 The X-axis of the axis and the body coordinate system of the middle frame p2 The X1 axis of the base body coordinate system coincides with the Y-axis of the follower frame body coordinate system. The base is fixed to the carrier. When the stable platform system undergoes internal relative rotation under the drive of the carrier: the base rotates around the Y-axis of the outer frame body coordinate system... p3 The axis rotates by an angle β. yk′ The X coordinate system of the outer frame around the middle frame body. p2 The axis rotates by an angle β. xk ; Y-axis of the middle frame around the inner frame body coordinate system p1 The axis rotates by an angle β. yk The Z-axis of the inner frame around the body coordinate system of the platform p The axis rotates by an angle β. zk .

[0062] like Figure 2 The flowchart shown illustrates the following steps in the compliant continuous variable structure control method for the servo loop inner frame limit of the four-axis inertial platform system of the present invention:

[0063] (1) Based on the angular velocity output by the gyroscope mounted on the platform, the position of the platform in the X direction is obtained. p Axis, Y p Axis and Z p angular velocity components on the axis

[0064] (2) The relative rotation angles inside the four-axis inertial stabilized platform system were measured, including: the X-axis of the outer frame around the coordinate system of the middle frame. p2 The angle β of the shaft rotation xk ; Y-axis of the middle frame around the inner frame body coordinate system p1 The angle β of the shaft rotation yk ; Z-axis of the inner frame around the body coordinate system of the platform p The angle β of the shaft rotation zk ;

[0065] (3) Given the value of the compliant variable structure parameter k (e.g., 4×10) -6 Or 2×10 -6 (etc.), calculate the angular velocity correction value of the compliant variable structure.

[0066]

[0067] Wherein, the interval parameter β ny β my β yk The minimum and maximum values.

[0068] (4) Based on the measured βxk β yk β zk , and In addition to the angular velocity correction value Δω, the rotational angular velocities of the platform, inner frame, middle frame, and outer frame are calculated using the following formulas:

[0069]

[0070] Where, ω z For Taiwan Z p The resultant rotational angular velocity of the shaft; ω y For the inner frame Y p1 The resultant rotational angular velocity of the shaft; ω x For the medium frame X p2 The resultant rotational angular velocity of the shaft; ω yk′ For the outer frame Y p3 The resultant rotational angular velocity of the shaft.

[0071] (5), ω z ω y ω x and ω yk′ The output is sent to the linear controller and then acts on the torque motors at each axis of the four-axis platform to stabilize the platform body relative to the inertial space.

[0072] The above-mentioned compliant continuous variable structure control method for the frame limit in the servo loop of the four-axis inertial stabilization platform measures the relative rotation angle inside the four-axis inertial stabilization platform system in step (2) using the following method:

[0073] X in the outer frame p2 An angle sensor is mounted on the axis to measure the X-axis of the outer frame around the coordinate system of the middle frame. p2 The angle β of the shaft rotation xk ; in the inner frame Y p1 An angle sensor is installed on the axis to measure the Y-axis of the middle frame around the inner frame's coordinate system. p1 The angle β of the shaft rotation yk ; in Taiwan Z p A sensor mounted on the axis measures the Z-axis coordinate of the inner frame around the body coordinate system of the stage. p The angle β of the shaft rotation zk .

[0074] In the above-mentioned compliant continuous variable structure control method for the frame limit in the servo loop of the four-axis inertial stabilization platform, in step (3), the rotation angle β yk The range of values ​​for β is ny ~β my , from (β ny +β my ) / 2=0° and (β)ny +β my Choose one of the two options from 180° () / 2; rotation angle β zk β xk β yk′ The value range is -180 to 180°.

[0075] To further illustrate the high precision of the decoupler of the present invention, two embodiments are given below.

[0076] Example 1:

[0077] Reference: "Research on Control Strategy of Four-Axis Inertial Platform Follower Frame, Navigation and Control, 2017, No. 4", assuming the inner frame limit value β. ny =-45°, β ny =45°, the area controlled by the locking partition discrete variable structure when the inner frame angle is limited is as follows: Figure 3 As shown. The main problem with this method is that the motion trajectory cannot cross from region 32 to region 31; it can only move forward by constantly switching along the boundary, causing the platform to shake.

[0078] Let β yk′ β xk β yk β zk The initial values ​​are 0°, 90°, 0°, and 0° respectively. When using variable structure zoning control, the initial position is in region 32. Let the angular velocity of the platform base be ω. x1 =0° / s, ω y1 =0° / s, ω z1 =50° / s.

[0079] The time-varying process of the frame angle in the locking-type discrete variable structure partition control when using inner frame angle limiting is as follows: Figure 4 As shown, the areas where the inner and outer frames are located are as follows: Figure 5 As shown, the change of the angular velocity of the platform with time is as follows: Figure 6 As shown, the angle θ between the platform and the inertial space x θ y θ z The process of change over time is as follows Figure 7 As shown. Throughout the entire operation, the inner frame angle never exceeded the limit of 45°, but during the switching process, both the platform's angular velocity and angle exhibited high-frequency vibrations. Specifically, the platform's angular velocity ω... xp The maximum value is approximately -291° / s, ω yp At the switching moment, the maximum value is approximately -167° / s, and the angle θ of the platform relative to the inertial space is... x At instantaneous closure at time zero, the maximum value can reach 1.983°, θ y The maximum value at the switching moment is approximately 0.96°.

[0080] When using the compliant continuous variable structure control method for inner frame limiting as described in this paper, the change process of the frame angle over time is as follows: Figure 8 As shown, the areas where the inner frame and middle frame angles are located are as follows: Figure 9 As shown, the change of the angular velocity of the platform with time is as follows: Figure 10 As shown, the angle θ between the platform and the inertial space x θ y θ z The process of change over time is as follows Figure 11 As shown. During operation, the angular velocity ω of the platform... xp The maximum is +3.26° / s, ω yp The maximum value is above -5.6° / s, and the angle θ of the platform relative to the inertial space is... x The maximum is +0.085°, θ y The maximum is 0.173°.

[0081] By comparing the partitioned discrete variable structure control with the compliant continuous variable structure control method of the present invention, it can be seen that the overshoot of the angle and angular velocity of the platform relative to the inertial space is significantly reduced, and there is no continuous swaying process. The method of the present invention has higher accuracy.

[0082] Example 2:

[0083] Let the inner frame limit value β ny =135°, β my =225°, β yk′ β xk β yk β zk The initial values ​​are 0°, 90°, 180°, and 0°. When the compliant continuous variable structure control method of the inner frame limit is used for control, the change process of the frame angle with time is as follows: Figure 12 As shown, the areas where the inner frame and middle frame angles are located are as follows: Figure 13 As shown, the change of the angular velocity of the platform with time is as follows: Figure 14 As shown, the angle θ between the platform and the inertial space x θ y θ z The process of change over time is as follows Figure 15 As shown. During operation, the angular velocity of the platform... The maximum is -3.25° / s. The maximum value is above -5.6° / s, and the angle θ of the platform relative to the inertial space is... x The maximum is -0.085°, θ y The maximum angle is 0.173°. It can be seen that the inner frame angle did not exceed the limit value during the entire operation, and the changes in the platform were relatively stable.

[0084] Implementation Method Two:

[0085] The compliant continuous variable structure control method for frame limiting in the servo loop of a four-axis inertial stabilization platform provided in this embodiment is implemented based on a four-axis inertial stabilization platform system. This four-axis stabilization platform system includes a base, outer frame, middle frame, inner frame, and platform body, with corresponding body coordinate systems of X1Y1Z1 for the base and X2Y1Z1 for the outer frame. p3 Y p3 Z p3 , Medium frame body coordinate system X p2 Y p2 Z p2 The inner frame body coordinate system X p1 Y p1 Z p1 and the X coordinate system of the platform body p Y p Z p .

[0086] like Figure 1 The diagram shows the relationship between the five coordinate systems. The origins of these five coordinate systems coincide, and they have the following relative constraints: the Z-axis of the platform body coordinate system... p Z-axis and the coordinate system of the inner frame p1 The axes coincide, and the Y-axis of the body coordinate system of the middle frame is... p2 Y-axis and the coordinate system of the inner frame p1 The axes coincide, and the X coordinate of the outer frame body coordinate system is... p3 The X-axis of the axis and the body coordinate system of the middle frame p2 The X1 axis of the base body coordinate system coincides with the Y-axis of the follower frame body coordinate system. The base is fixed to the carrier. When the stable platform system undergoes internal relative rotation under the drive of the carrier: the base rotates around the Y-axis of the outer frame body coordinate system... p3 The axis rotates by an angle β. yk′ The X coordinate system of the outer frame around the middle frame body. p2 The axis rotates by an angle β. xk ; Y-axis of the middle frame around the inner frame body coordinate system p1 The axis rotates by an angle β. yk The Z-axis of the inner frame around the body coordinate system of the platform p The axis rotates by an angle β. zk .

[0087] like Figure 2 The processing flowchart shown illustrates the following steps of the compliant continuous variable structure control method for frame limiting in the servo loop of the four-axis inertial platform system of the present invention:

[0088] (1) Based on the angular velocity output by the gyroscope mounted on the platform, the position of the platform in the X direction is obtained. p Axis, Y p Axis and Z p angular velocity components on the axis

[0089] (2) The relative rotation angles inside the four-axis inertial stabilized platform system were measured, including: the X-axis of the outer frame around the coordinate system of the middle frame. p2 The angle β of the shaft rotation xk ; Y-axis of the middle frame around the inner frame body coordinate system p1 The angle β of the shaft rotation yk ; Z-axis of the inner frame around the body coordinate system of the platform p The angle β of the shaft rotation zk ;

[0090] (3) Given the value of the compliant variable structure parameter k (e.g., 4×10) -6 Or 2×10 -6 (etc.), calculate the angular velocity correction value of the compliant variable structure.

[0091]

[0092] Wherein, the interval parameter β nx β mx β xk The minimum and maximum values.

[0093] (4) Based on the measured β xk β yk β zk ω xp ω yp and ω zp And the angular velocity correction value Δω, to calculate the rotational angular velocities of the platform, inner frame, middle frame and outer frame. The specific calculation formula is as follows:

[0094]

[0095] Where, ω z For Taiwan Z p The resultant rotational angular velocity of the shaft; ω y For the inner frame Y p1 The resultant rotational angular velocity of the shaft; ω x For the medium frame X p2 The resultant rotational angular velocity of the shaft; ω yk′ For the outer frame Y p3 The resultant rotational angular velocity of the shaft.

[0096] (5), ω z ω y ω x and ωyk′ The output is sent to the linear controller and then acts on the torque motors at each axis of the four-axis platform to stabilize the platform body relative to the inertial space.

[0097] In the above-mentioned compliant continuous variable structure control method for frame limiting in the servo loop of the four-axis inertial stabilization platform, the relative rotation angle inside the four-axis inertial stabilization platform system is measured in step (2) by the following method:

[0098] X in the outer frame p2 An angle sensor is mounted on the axis to measure the X-axis of the outer frame around the coordinate system of the middle frame. p2 The angle β of the shaft rotation xk ; in the inner frame Y p1 An angle sensor is installed on the axis to measure the Y-axis of the middle frame around the inner frame's coordinate system. p1 The angle β of the shaft rotation yk ; in Taiwan Z p A sensor mounted on the axis measures the Z-axis coordinate of the inner frame around the body coordinate system of the stage. p The angle β of the shaft rotation zk .

[0099] In the above-mentioned compliant continuous variable structure control method for frame limiting in the servo loop of the four-axis inertial stabilization platform, in step (3), the rotation angle β xk The range of values ​​for β is nx ~β mx The interval parameter satisfies (β) nx +β mx ) / 2=0° or (β) nx +β mx ) / 2 = 180°; rotation angle β yk The value range is -90 to 270°; rotation angle β zk β yk′ The value range is -180 to 180°.

[0100] To further illustrate the high precision of the decoupler of the present invention, three embodiments are given below.

[0101] Example 1:

[0102] Reference: "Research on Control Strategy of Four-Axis Inertial Platform Follower Frame, Navigation and Control, 2017, No. 4", assuming the inner frame limit value β. ny =45°, β ny =135°, the area controlled by the locking partition discrete variable structure when the inner frame angle is limited is as follows: Figure 3 As shown. The main problem with this method is that the motion trajectory cannot cross from region 32 to region 31; it can only move forward by constantly switching along the boundary, causing the platform to shake.

[0103] Let β yk′ β xk β yk β zk The initial values ​​are 0°, 90°, 0°, and 0° respectively. When using variable structure zoning control, the initial position is in region 32. Let the platform base angular velocity...

[0104] The time-varying process of the frame angle in the locking-type discrete variable structure partition control when using inner frame angle limiting is as follows: Figure 4 As shown, the areas where the inner and outer frames are located are as follows: Figure 5 As shown, the change of the angular velocity of the platform with time is as follows: Figure 6 As shown, the angle θ between the platform and the inertial space x θ y θ z The process of change over time is as follows Figure 7 As shown. Throughout the entire operation, the inner frame angle never exceeded the limit of 45°, but during the switching process, both the platform's angular velocity and angle exhibited high-frequency vibrations. Specifically, the platform's angular velocity... The maximum value is approximately -291° / s. At the switching moment, the maximum value is approximately -167° / s, and the angle θ of the platform relative to the inertial space is... x At instantaneous closure at time zero, the maximum value can reach 1.983°, θ y The maximum value at the switching moment is approximately 0.96°.

[0105] To overcome the swaying problem, the inner frame is set to be unlimited, while the middle frame is set to a limit value β. nx =45°, β nx =135°, when using the compliant continuous variable structure control method of the middle frame limit in this paper for control, the change process of the frame angle with time is as follows: Figure 16 As shown, the areas where the inner frame and middle frame angles are located are as follows: Figure 17 As shown, the change of the angular velocity of the platform with time is as follows: Figure 18 As shown, the angle θ between the platform and the inertial space x θ y θ z The process of change over time is as follows Figure 19 As shown. During operation, the angular velocity of the platform... The angle θ between the platform and the inertial space x θ y It is close to zero.

[0106] By comparing the partitioned discrete variable structure control with the compliant continuous variable structure control method of the present invention, it can be seen that the overshoot of the angle and angular velocity of the platform relative to the inertial space is significantly reduced, and there is no continuous swaying process. The method of the present invention has higher accuracy.

[0107] Example 2:

[0108] Assume the inner frame is not limited, while the middle frame is limited by a value β. nx =45°, β nx =135°, β yk′ β xk β yk β zk The initial values ​​are 0°, 90°, 0°, and 0°, respectively, and the base angular velocity is... When using the compliant continuous variable structure control method for the mid-frame limit in this paper, the change process of the frame angle over time is as follows: Figure 20 As shown, the areas where the inner frame and middle frame angles are located are as follows: Figure 21 As shown, the change of the angular velocity of the platform with time is as follows: Figure 22 As shown, the angle θ between the platform and the inertial space x θ y θ z The process of change over time is as follows Figure 23 As shown. During operation, the angular velocity of the platform... The maximum is +5.935° / s. The maximum is above 4.6° / s, and the angle θ of the platform relative to the inertial space is... x The maximum is -0.1414°, θ y The maximum angle is 0.1537°. It can be seen that during the entire operation, the angle of the middle frame did not exceed the limit value, and the changes in the platform were relatively stable.

[0109] Example 3:

[0110] Assume the inner frame is not limited, while the middle frame is limited by a value β. nx =-135°, β nx = -45°, β yk′ β xk β yk β zk The initial values ​​are 0°, -90°, 0°, and 0°, respectively, and the base angular velocity ω x1 =50° / s, ω y1 =0° / s, ω z1 =0° / s, when using the compliant continuous variable structure control method of the middle frame limit in this paper for control, the change process of the frame angle with time is as follows: Figure 24 As shown, the areas where the inner frame and middle frame angles are located are as follows: Figure 25As shown, the change of the angular velocity of the platform with time is as follows: Figure 26 As shown, the angle θ between the platform and the inertial space x θ y θ z The process of change over time is as follows Figure 27 As shown. During operation, the angular velocity of the platform... The maximum is +5.93° / s. The maximum is above 4.6° / s, and the angle θ of the platform relative to the inertial space is... x The maximum is -0.141°, θ y The maximum angle is 0.153°. It can be seen that the angle of the middle frame did not exceed the limit value during the entire operation, and the changes in the platform were relatively stable.

[0111] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0112] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A compliant continuous variable structure control method for a four-axis inertial stabilization platform under servo loop frame limiting conditions, characterized in that, For the inner frame limit, the control methods include: Based on the angular velocity output by the gyroscope mounted on the platform, the position of the platform in the X direction is obtained. p Axis, Y p Axis and Z p angular velocity components on the axis Measuring the X-axis of the outer frame around the coordinate system of the middle frame p2 The angle β of the shaft rotation xk The Y-axis of the middle frame around the inner frame's body coordinate system p1 The angle β of the shaft rotation yk Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk ; Given the value of parameter k of the compliant variable structure, calculate the angular velocity correction value of the compliant variable structure: Wherein, the interval parameter β ny β my β yk The minimum and maximum values; Based on the measured β xk β yk β zk , and In addition to the angular velocity correction value Δω, the combined rotational angular velocity of the platform, inner frame, middle frame, and outer frame is calculated. The specific calculation formula is as follows: Where, ω z For Taiwan Z p The resultant rotational angular velocity of the shaft; ω y For the inner frame Y p1 The resultant rotational angular velocity of the shaft; ω x For the medium frame X p2 The resultant rotational angular velocity of the shaft; ω yk′ For the outer frame Y p3 The resultant rotational angular velocity of the shaft; ω z ω y ω x and ω yk′ The output is fed to a linear controller and then acts on the torque motors at each axis of the four-axis inertial stabilization platform to achieve the stabilization of the platform relative to the inertial space.

2. The compliant continuous variable structure control method according to claim 1, characterized in that, The four-axis inertial stabilization platform consists of a base, an outer frame, a middle frame, an inner frame, and a platform body. The corresponding body coordinate systems are the base body coordinate system (X1Y1Z1) and the outer frame body coordinate system (X...). p3 Y p3 Z p3 , Medium frame body coordinate system X p2 Y p2 Z p2 The inner frame body coordinate system X p1 Y p1 Z p1 and the X coordinate system of the platform body p Y p Z p The origins of the five coordinate systems coincide, and: the Z-axis of the platform body coordinate system... p Z-axis and the coordinate system of the inner frame p1 The axes coincide, and the Y-axis of the body coordinate system of the middle frame is... p2 Y-axis and the coordinate system of the inner frame p1 The axes coincide, and the X coordinate of the outer frame body coordinate system is... p3 The X-axis of the axis and the body coordinate system of the middle frame p2 The axes coincide, the X1 axis of the base body coordinate system and the Y axis of the outer frame body coordinate system. p3 The axes coincide; wherein, the base is fixedly connected to the carrier, and when the stable platform system undergoes internal relative rotation under the drive of the carrier, the base revolves around the Y-axis of the outer frame's body coordinate system. p3 The axis rotates, and the outer frame revolves around the X coordinate system of the middle frame. p2 The axis rotates, and the middle frame rotates around the Y-axis of the inner frame's body coordinate system. p1 The axis rotates, and the inner frame rotates around the Z-axis of the platform's coordinate system. p The shaft rotates.

3. The compliant continuous variable structure control method according to claim 1, characterized in that, The relative rotation angle and angular velocity inside the four-axis inertial stabilized platform were measured using the following method: X in the middle frame p2 An angle sensor is mounted on the axis to measure the X-axis of the outer frame around the coordinate system of the middle frame. p2 The angle β of the shaft rotation xk ; in the inner frame Y p1 An angle sensor is installed on the axis to measure the Y-axis of the middle frame around the inner frame's coordinate system. p1 The angle β of the shaft rotation yk ; in Taiwan Z p A sensor mounted on the axis measures the Z-axis coordinate of the inner frame around the body coordinate system of the stage. p The angle β of the shaft rotation zk .

4. The compliant continuous variable structure control method according to claim 1, characterized in that, Rotation angle β yk The range of values ​​for β is ny ~β my Rotation angle β zk β xk β yk The value of ′ ranges from -180 to 180°.

5. The compliant continuous variable structure control method according to claim 4, characterized in that, The interval parameter satisfies the following conditions: (β ny + β my ) / 2 = 0° or (β ny + β my ) / 2 = 180°.

6. A compliant continuous variable structure control method for a four-axis inertial stabilization platform under servo loop frame limiting conditions, characterized in that, For the mid-frame limit, the control methods include: Based on the angular velocity output by the gyroscope mounted on the platform, the position of the platform in the X direction is obtained. p Axis, Y p Axis and Z p angular velocity components on the axis Measuring the X-axis of the outer frame around the coordinate system of the middle frame p2 The angle β of the shaft rotation xk The Y-axis of the middle frame around the inner frame's body coordinate system p1 The angle β of the shaft rotation yk Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk ; Given the value of parameter k of the compliant variable structure, calculate the angular velocity correction value of the compliant variable structure: Wherein, the interval parameter β nx β mx β xk The minimum and maximum values; Based on the measured β xk β yk β zk , and In addition to the angular velocity correction value Δω, the combined rotational angular velocity of the platform, inner frame, middle frame, and outer frame is calculated. The specific calculation formula is as follows: Where, ω z For Taiwan Z p The resultant rotational angular velocity of the shaft; ω y For the inner frame Y p1 The resultant rotational angular velocity of the shaft; ω x For the medium frame X p2 The resultant rotational angular velocity of the shaft; ω yk′ For the outer frame Y p3 The resultant rotational angular velocity of the shaft; ω z ω y ω x and ω yk′ The output is fed to a linear controller and then acts on the torque motors at each axis of the four-axis inertial stabilization platform to achieve the stabilization of the platform relative to the inertial space.

7. The compliant continuous variable structure control method according to claim 6, characterized in that, The four-axis inertial stabilization platform consists of a base, an outer frame, a middle frame, an inner frame, and a platform body. The corresponding body coordinate systems are the base body coordinate system (X1Y1Z1) and the outer frame body coordinate system (X...). p3 Y p3 Z p3 , Medium frame body coordinate system X p2 Y p2 Z p2 The inner frame body coordinate system X p1 Y p1 Z p1 and the X coordinate system of the platform body p Y p Z p The origins of the five coordinate systems coincide, and: the Z-axis of the platform body coordinate system... p Z-axis and the coordinate system of the inner frame p1 The axes coincide, and the Y-axis of the body coordinate system of the middle frame is... p2 Y-axis and the coordinate system of the inner frame p1 The axes coincide, and the X coordinate of the outer frame body coordinate system is... p3 The X-axis of the axis and the body coordinate system of the middle frame p2 The axes coincide, the X1 axis of the base body coordinate system and the Y axis of the outer frame body coordinate system. p3 The axes coincide; wherein, the base is fixedly connected to the carrier, and when the stable platform system undergoes internal relative rotation under the drive of the carrier, the base revolves around the Y-axis of the outer frame's body coordinate system. p3 The axis rotates, and the outer frame revolves around the X coordinate system of the middle frame. p2 The axis rotates, and the middle frame rotates around the Y-axis of the inner frame's body coordinate system. p1 The axis rotates, and the inner frame rotates around the Z-axis of the platform's coordinate system. p The shaft rotates.

8. The compliant continuous variable structure control method according to claim 6, characterized in that, The relative rotation angles and angular velocities within the four-axis inertial stabilized platform system were measured using the following method: X in the middle frame p2 An angle sensor is mounted on the axis to measure the X-axis of the outer frame around the coordinate system of the middle frame. p2 The angle β of the shaft rotation xk ; in the inner frame Y p1 An angle sensor is installed on the axis to measure the Y-axis of the middle frame around the inner frame's coordinate system. p1 The angle β of the shaft rotation yk ; in Taiwan Z p A sensor mounted on the axis measures the Z-axis coordinate of the inner frame around the body coordinate system of the stage. p The angle β of the shaft rotation zk .

9. The compliant continuous variable structure control method according to claim 6, characterized in that, Rotation angle β xk The range of values ​​for β is nx ~β mx Rotation angle β yk The value range is -90 to 270°; rotation angle β zk β yk The value of ′ ranges from -180 to 180°.

10. The compliant continuous variable structure control method according to claim 6, characterized in that, The interval parameter satisfies the following conditions: (β nx + β mx ) / 2 = 0° or (β nx + β mx ) / 2 = 180°.

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