A discrete variable structure control method for servo loop of four-axis inertially stabilized platform

Abstract

A four-axis inertial stabilization platform servo loop discrete variable structure control method, taking a hybrid discrete variable structure control as an example, comprises the following steps of: obtaining angular velocity components of a platform body on X p axis, Y p axis and Z p axis and obtaining an angle and angular velocity of internal relative rotation of a four-axis inertial stabilization platform system according to angular velocity output by a gyroscope mounted on the platform body; performing partition variable structure control based on the size of an actuator angular velocity component and combining angle limitation according to the angular velocity components and the angle of the internal relative rotation, so as to respectively calculate a resultant rotation angular velocity ω p of the platform body on the Z z axis, a resultant rotation angular velocity ω p1 of an inner frame on the Y y axis, a resultant rotation angular velocity ω p2 of a middle frame on the X x axis and a resultant rotation angular velocity ω p3 of an outer frame on the Y yk′ axis. The method can avoid singular values in a servo loop decoupling process and ensure that the platform body is stable relative to inertial space.

Description

Technical Field

[0001] This invention relates to a discrete variable structure control method for a servo loop of a four-axis inertial stabilization platform, in the field of inertial measurement technology. Background Technology

[0002] Because three-axis inertial platform systems suffer from "frame locking," making it difficult to meet the requirements of large-scale maneuvering of the platform, four-axis inertial platform systems were developed. Compared to three-axis inertial platform systems, four-axis inertial platform systems add an outer frame to the platform body, inner frame, and middle frame. The outer frame is located between the middle frame and the base of the platform.

[0003] To stabilize the platform relative to inertial space, the traditional solution is as follows: the servo loop is based on the inner frame angle β. yk and the angle β of the middle frame xk Different decouplers are used in different regions, see the reference "Variable Structure Partition Control of Four-Axis Gyroscope Stabilized Platform, Tsinghua University Journal Vol.50, No.7, 2010". The reason for using partition control is that when controlling the four axis motors in conjunction with the outputs of the three gyroscopes and any frame angle, there is a region where the motor driving torque is infinite, which may cause control failure.

[0004] When the carrier moves, the angles of the inner frame and the middle frame will be in different ranges. When using zone control, there is a switching between different control signals. Even if the switching condition with hysteresis relay characteristics is used, the platform will still experience instantaneous shaking at the switching moment, resulting in the platform body swaying relative to the space. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and solve the problem of high-precision maintenance capability of the platform relative to the inertial space.

[0006] The objective of this invention is achieved through the following technical solutions:

[0007] A hybrid discrete variable structure control method for a four-axis inertial stabilization platform using a servo loop includes:

[0008] (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

[0009] (2) Measure the X coordinate system of the outer frame around the middle frame body. 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 ykand angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity

[0010] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0011] (3.1) Set the threshold angle β f The value;

[0012] (3.2) When β xk β yk Satisfy condition |cosβ xk |≥|sinβ xk cosβ yk |and|cosβ xk ||≥sinβ yk |, or |sinβ yk |>|cosβ xk |and|sinβ yk |≥|sinβ xk cosβ yk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows:

[0013]

[0014]

[0015]

[0016]

[0017] (3.3) When β xk β yk The condition in (3.2) is not satisfied, but the condition |sinβ is satisfied. xk cosβ yk |≥|sinβ yk When |, the specific calculation formula is as follows:

[0018]

[0019]

[0020]

[0021]

[0022] (3.4) When βxk β yk When conditions (3.2) and (3.3) are not met, the specific calculation formula is as follows:

[0023]

[0024]

[0025]

[0026]

[0027] 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.

[0028] A semi-stable partitioned discrete variable structure control method for a four-axis inertial stabilization platform using a combined servo loop includes:

[0029] (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

[0030] (2) Measure the X coordinate system of the outer frame around the middle frame body. 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity

[0031] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0032] (3.1) Set the threshold angle β f The value;

[0033] (3.2) When β xk β yk Satisfy condition |cosβ xk |≥|sinβxk cosβ yk |and|cosβ xk |≥|sinβ yk |, or |sinβ yk |>|cosβ xk |and|sinβ yk |≥|sinβ xk cosβ yk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows:

[0034]

[0035]

[0036]

[0037]

[0038] (3.3) When β xk β yk When condition (3.2) is not met, the specific calculation formula is as follows:

[0039]

[0040]

[0041]

[0042]

[0043] 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.

[0044] A servo loop-coordinated semi-stable partitioned discrete variable structure control method for a four-axis inertial stabilization platform includes:

[0045] (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

[0046] (2) Measure the X coordinate system of the outer frame around the middle frame body. 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity

[0047] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0048] (3.1) Set the threshold angle β f The value;

[0049] (3.2) When β xk β yk Satisfy condition | secβ xk secβ yk |≤|cscβ xk |, or |secβ xk secβ yk |>|cscβ xk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows:

[0050]

[0051]

[0052]

[0053]

[0054] (3.3) When β xk β yk When condition (3.2) is not met, the specific calculation formula is as follows:

[0055]

[0056]

[0057]

[0058]

[0059] Where, ω z For Taiwan Z pThe 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.

[0060] A servo loop locking-type partitioned discrete variable structure control method for a four-axis inertial stabilization platform includes:

[0061] (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

[0062] (2) Measure the Y-axis of the base around the outer frame coordinate system. p3 The angle β of the shaft rotation yk′ and angular velocity The outer frame around the middle frame's body coordinate system X p2 The angle β of the shaft rotation xk and angular velocity Y-axis of the middle frame around the inner frame body coordinate system p1 The angle β of the shaft rotation yk and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk ;

[0063] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0064] (3.1) Set the threshold angle β f The value;

[0065] (3.2) When β xk β yk Meet the conditions And |sinβ xk |≥|sinβ f When |, the specific calculation formula is as follows:

[0066]

[0067]

[0068]

[0069]

[0070] (3.3) When β xk β yk Meet the conditions And |sinβ xk When |≥|sin46.457°|, the specific calculation formula is as follows:

[0071]

[0072]

[0073]

[0074]

[0075] (3.4) When β xk β yk When conditions (3.2) and (3.3) are not met, the specific calculation formula is as follows:

[0076]

[0077]

[0078]

[0079]

[0080] 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. Attached Figure Description

[0081] Figure 1 This is a schematic diagram illustrating the relationship between five body coordinate systems in a four-axis inertial stabilization platform system according to an embodiment of the present invention.

[0082] Figure 2 This is a flowchart of the steps of a servo loop hybrid discrete variable structure control method for a four-axis inertial stabilization platform system proposed in this invention.

[0083] Figure 3 It is a region divided according to the angles of the inner frame and the middle frame in the variable structure zoning control;

[0084] Figure 4 This describes the change of the frame angle over time during the implementation of the variable structure zoning control method.

[0085] Figure 5 This refers to the area where the angles of the inner frame and the middle frame are located during the structural zoning control implementation method 1.

[0086] Figure 6 This describes the change of the platform's angular velocity over time during implementation of the variable structure zoning control method.

[0087] Figure 7 This describes the change in the angle of the platform relative to the inertial space over time during implementation of the variable structure zoning control method.

[0088] Figure 8 This describes the change of the frame angle over time when using the hybrid discrete variable structure control method of Implementation Method 1.

[0089] Figure 9 This refers to the region where the angles of the inner frame and the middle frame are located when using the hybrid discrete variable structure control method of Implementation Method 1.

[0090] Figure 10 This describes the change of the platform's angular velocity over time when using the hybrid discrete variable structure control method of Implementation Method 1.

[0091] Figure 11 This describes the change in the angle of the platform relative to the inertial space over time when using the hybrid discrete variable structure control method of Implementation Method 1.

[0092] Figure 12 This describes the change of the frame angle over time during the implementation of the second method of variable structure zoning control.

[0093] Figure 13 This refers to the area where the angles of the inner frame and the middle frame are located during the variable structure zoning control in Implementation Method Two;

[0094] Figure 14 This describes the change of the platform's angular velocity over time during the implementation of the variable structure zoning control method in Implementation Method 2.

[0095] Figure 15 This describes the change in the angle of the platform relative to the inertial space over time during implementation of the variable structure zoning control method in Implementation Method 2.

[0096] Figure 16 This describes the change of the frame angle over time when using the combined semi-stable partitioned discrete variable structure control method of Implementation Method 2.

[0097] Figure 17 This refers to the region where the angles of the inner frame and the middle frame are located when using the combined semi-stable partitioned discrete variable structure control in Implementation Method 2.

[0098] Figure 18This describes the change of the platform's angular velocity over time when using the combined semi-stable partitioned discrete variable structure control method of Implementation Method 2.

[0099] Figure 19 This describes the change in the angle of the platform relative to the inertial space over time when using the combined semi-stable partitioned discrete variable structure control method of Implementation Method 2.

[0100] Figure 20 This describes the change of the frame angle over time during the implementation of the three-dimensional structural zoning control method.

[0101] Figure 21 This refers to the area where the inner frame and middle frame angles are located during the implementation of the three-dimensional structural zoning control method;

[0102] Figure 22 This describes the change of the platform's angular velocity over time during the implementation of the three-variable structure zone control method.

[0103] Figure 23 The process of the angle of the platform relative to the inertial space changing over time when implementing the three-variable structure zoning control method;

[0104] Figure 24 This describes the change of the frame angle over time when using the third implementation method of collaborative semi-stable partitioned discrete variable structure control.

[0105] Figure 25 This refers to the region where the angles of the inner and outer frames are located when using the third implementation method of collaborative semi-stable partitioned discrete variable structure control.

[0106] Figure 26 This describes the change of the platform's angular velocity over time when using the third implementation method of collaborative semi-stable partitioned discrete variable structure control.

[0107] Figure 27 This describes the change in the angle of the platform relative to the inertial space over time when using the third implementation method of collaborative semi-stable partitioned discrete variable structure control.

[0108] Figure 28 This is a flowchart of the steps of a servo loop locking partitioned discrete variable structure control method for a four-axis inertial stabilization platform system, as described in Implementation Method Four.

[0109] Figure 29 This refers to the area divided according to the angles of the inner frame and the middle frame in the four-dimensional structural zoning control implementation method.

[0110] Figure 30 This describes the change of the frame angle over time during the implementation of the four-dimensional structural zoning control method.

[0111] Figure 31 This refers to the area where the angles of the inner frame and the middle frame are located during the implementation of the four-dimensional structural zoning control method.

[0112] Figure 32 This describes the change of the platform's angular velocity over time during the implementation of the four-variable structure zone control method.

[0113] Figure 33 The process of the angle of the platform relative to the inertial space changing over time when implementing the four-variable structure zoning control method;

[0114] Figure 34 This describes the change of the frame angle over time when using the fourth implementation method of locked partition discrete variable structure control.

[0115] Figure 35 This refers to the area where the angles of the inner and outer frames are located when using the fourth implementation method of locked-zone discrete variable structure control.

[0116] Figure 36 This describes the change of the platform's angular velocity over time when using the fourth-level locking partitioned discrete variable structure control method.

[0117] Figure 37 This describes the change in the angle of the platform relative to the inertial space over time when using the fourth implementation method of locked-zone discrete variable structure control. Detailed Implementation

[0118] 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.

[0119] Implementation Method 1:

[0120] This invention provides a hybrid discrete variable structure control method for a four-axis inertial stabilization platform servo loop, implemented based on a four-axis inertial stabilization platform system. By setting reasonable ranges for the inner frame angle and middle frame angle of the four-axis platform, the correlation between the stabilized angular velocity in the servo loop and the actuator is maximized while minimizing proximity to singular points, thereby minimizing the influence of the servo loop on the stabilization loop and ensuring that the switching control process balances overshoot and all attitudes. The 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 .

[0121] 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 .

[0122] like Figure 2 The processing flowchart shown illustrates the implementation steps of the servo loop hybrid discrete variable structure control method for the four-axis inertial platform system of this invention:

[0123] (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

[0124] (2) The relative rotation angles and angular velocities within 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity

[0125] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0126] (3.1) Set the threshold angle β f The value (e.g., 15°);

[0127] (3.2) When β xk β yk Satisfy condition |cosβ xk |≥|sinβ xk cosβ yk |and|cosβ xk |≥|sinβ yk |, or |sinβ yk |>|cosβ xk |and|sinβ yk |≥|sinβ xk cosβ yk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows:

[0128]

[0129]

[0130]

[0131]

[0132] (3.3) When β xk β yk The condition in (3.2) is not satisfied, but the condition |sinβ is satisfied. xk cosβ yk |≥|sinβ yk When |, the specific calculation formula is as follows:

[0133]

[0134]

[0135]

[0136]

[0137] (3.4) When β xk β yk When conditions (3.2) and (3.3) are not met, the specific calculation formula is as follows:

[0138]

[0139]

[0140]

[0141]

[0142] 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.

[0143] The above-mentioned hybrid discrete variable structure control method for the servo loop of the four-axis inertial stabilization platform obtains the relative rotation angle and angular velocity inside the four-axis inertial stabilization platform system in step (2) by measuring the following method:

[0144] 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 and angular velocity In Taiwan Sports 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 and angular velocity

[0145] In the above-mentioned hybrid discrete variable structure control method for a four-axis inertial stabilization platform servo loop, in step (3), the rotation angle β yk The value range is -90 to 270°; rotation angle β zk β xk β yk′ The value range is -180 to 180°.

[0146] The angles that satisfy condition (3.2) include the following 6 closed regions:

[0147] (4.1) A closed region consisting of 7 straight lines and 1 curve, with equations of the lines and curve as follows:

[0148]

[0149] (4.2) A closed region consisting of 10 straight lines and 2 curves, the equations of the straight lines and curves are:

[0150]

[0151] (4.3) A closed region consisting of 7 straight lines and 1 curve, the equations of the straight lines and the curve are:

[0152]

[0153] (4.4) A closed region consisting of 7 straight lines and 1 curve, the equations of the straight lines and the curve are:

[0154]

[0155] (4.5) A closed region consisting of 10 straight lines and 2 curves, the equations of the straight lines and curves are:

[0156] (4.6) A closed region consisting of 7 straight lines and 1 curve has the equations of the lines and the curve as follows:

[0157] The angles that satisfy condition (3.3) include the following four closed regions:

[0158] (5.1) A closed region consisting of 4 curves, the equations of which are:

[0159]

[0160] (5.2) The closed region is formed by four curves, and the equations of the curves are:

[0161]

[0162] (5.3) A closed region consisting of 4 curves, the equations of which are:

[0163]

[0164] (5.4) A closed region consisting of four curves, the equations of which are:

[0165]

[0166] The angles that satisfy condition (3.4) include the following 6 closed regions:

[0167] (6.1) A closed region consisting of 5 straight lines and 1 curve, with equations of the lines and curve as follows:

[0168] (6.2) A closed region consisting of 5 straight lines and 1 curve, with equations of the lines and curve as follows:

[0169] (6.3) A closed region consisting of 6 straight lines and 2 curves, with equations of the lines and curves as follows:

[0170] (6.4) A closed region consisting of 6 straight lines and 2 curves has the equations of the lines and curves as follows:

[0171] (6.5) A closed region consisting of 5 straight lines and 1 curve, with equations of the lines and curve as follows:

[0172]

[0173] (6.6) A closed region consisting of 5 straight lines and 1 curve has the equations of the lines and the curve as follows:

[0174]

[0175] To further illustrate that the decoupler of the present invention has the characteristic of minimum energy consumption, an embodiment is given below.

[0176] Example:

[0177] Reference "Variable Structure Partition Control of a Quad-Axis Gyroscope Stabilized Platform, Tsinghua University Journal Vol.50, No.7, 2010", the determined variable structure control region is as follows: Figure 3 As shown.

[0178] Let β yk′ β xk β yk β zk The initial values ​​are 0°, 60°, 90°, and 0° respectively. When using variable structure zoning control, the initial position is in region 4. Let the platform base angular velocity...

[0179] The time-varying process of the frame angle controlled by variable structure zoning is as follows: Figure 4 As shown, the areas where the inner frame and middle frame angles 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. At 0.5s, the platform enters region 1 from region 4, and the angular velocity of the platform is... Up to -800° / s The angle θ of the platform relative to inertial space can reach over -910° / s. x At the switching moment, it can reach 4.4°, θ yThe temperature can reach -6.5°C at the switching moment.

[0180] When the hybrid discrete variable structure control method of this invention is used for control, 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. At 1.5s, the platform enters region 1 from region 4, and the angular velocity of the platform is... Up to 360° / s The angle θ of the platform relative to inertial space can reach over -104° / s. x At the switching moment, it can reach 2.3°, θ y The temperature can reach -0.76° at the switching moment.

[0181] By comparing the variable structure partition control with the hybrid discrete variable structure control method of this invention, it can be seen that the overshoot of the angle and angular velocity relative to the inertial space of the platform is significantly reduced during the region switching process, and the method of this invention has higher accuracy. Moreover, the hybrid discrete variable structure control method of this invention has the ability to avoid singular points, ensuring that the inertial platform has full attitude control capabilities.

[0182] This embodiment has the following advantages:

[0183] (1) The servo loop hybrid discrete variable structure control method given in this embodiment has the advantage of less interference of the follower loop on the stage compared with the equal interval angle partition variable structure control method. Therefore, the decoupling method of this embodiment can enable the stage to maintain a high degree of accuracy relative to the inertial space.

[0184] (2) The servo loop hybrid discrete variable structure control method given in this embodiment has the characteristic of smaller output energy compared with the equal interval angle partition variable structure control method, which is beneficial to saving control energy.

[0185] (3) The four-axis inertial stabilization platform system described in this embodiment has the characteristics of full attitude compared with the hybrid discrete variable structure variable structure control method. It avoids the approximate simplification measures of the decoupler at singular points, which is beneficial to the adaptability of the four-axis inertial platform to the full attitude motion of the carrier.

[0186] Implementation Method Two:

[0187] This invention provides a semi-stable, partitioned, discrete variable structure control method for a four-axis inertial stabilization platform, based on a four-axis inertial stabilization platform system. By setting reasonable ranges for the inner frame angle and middle frame angle of the four-axis platform, the correlation between the stabilized angular velocity in the servo loop and the actuator is maximized while minimizing proximity to singular points, thereby minimizing the influence of the servo loop on the stabilization loop and ensuring that the switching control process balances overshoot and all attitudes. The 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 .

[0188] 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 .

[0189] like Figure 2 The processing flowchart shown illustrates the implementation steps of the servo loop combination semi-stable partitioned discrete variable structure control method for the four-axis inertial platform system of the present invention:

[0190] (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

[0191] (2) The relative rotation angles and angular velocities within 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity

[0192] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0193] (3.1) Set the threshold angle β f The value (e.g., 15°);

[0194] (3.2) When β xk β yk Satisfy condition |cosβ xk |≥|sinβ xk cosβ yk |and|cosβ xk |≥|sinβ yk |, or |sinβ yk |>|cosβ xk |and|sinβ yk |≥|sinβ xk cosβ yk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows:

[0195]

[0196]

[0197]

[0198]

[0199] (3.3) When β xk β ykWhen condition (3.2) is not met, the specific calculation formula is as follows:

[0200]

[0201]

[0202]

[0203]

[0204] 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.

[0205] The aforementioned servo loop combined semi-stable partitioned discrete variable structure control method for a four-axis inertial stabilized platform measures the relative rotation angle and angular velocity within the four-axis inertial stabilized platform system in step (2) using the following method:

[0206] 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 and angular velocity In Taiwan Sports 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 and angular velocity

[0207] In the above-mentioned four-axis inertial stabilization platform servo loop combination semi-stable partitioned discrete variable structure control method, in step (3), the rotation angle β yk The value range is -90 to 270°; rotation angle β zk β xk β yk′ The value range is -180 to 180°.

[0208] The angles that satisfy condition (3.2) include the following 6 closed regions:

[0209] (4.1) A closed region consisting of 7 straight lines and 1 curve, with equations of the lines and curve as follows:

[0210]

[0211] (4.2) A closed region consisting of 10 straight lines and 2 curves, the equations of the straight lines and curves are:

[0212]

[0213] (4.3) A closed region consisting of 7 straight lines and 1 curve, the equations of the straight lines and the curve are:

[0214]

[0215] (4.4) A closed region consisting of 7 straight lines and 1 curve, the equations of the straight lines and the curve are:

[0216] (4.5) A closed region consisting of 10 straight lines and 2 curves, the equations of the straight lines and curves are:

[0217]

[0218] (4.6) A closed region consisting of 7 straight lines and 1 curve has the equations of the lines and the curve as follows:

[0219]

[0220] The angles that satisfy condition (3.3) include the following two closed regions:

[0221] (5.1) A closed region consisting of 16 straight lines and 4 curves, with the equations of the curves being:

[0222]

[0223] (5.2) A closed region consisting of 16 straight lines and 4 curves, with the equations of the curves being:

[0224]

[0225] To further illustrate that the decoupler of the present invention has the characteristic of minimum energy consumption, an embodiment is given below.

[0226] Example:

[0227] Reference "Variable Structure Partition Control of a Quad-Axis Gyroscope Stabilized Platform, Tsinghua University Journal Vol.50, No.7, 2010", the determined variable structure control region is as follows: Figure 3 As shown.

[0228] Let β yk′β xk β yk β zk The initial values ​​are 0°, 90°, 90°, and 0° respectively. When using variable structure zoning control, the initial position is in region 4. Let the platform base angular velocity...

[0229] The time-varying process of the frame angle controlled by variable structure zoning is as follows: Figure 12 As shown, the areas where the inner frame angle and the middle frame angle 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. At 1.5s, the platform moves from region 4 to region 3, and the three angular velocities of the platform are approximately zero. The maximum instantaneous value at time zero is approximately 2 × 10⁻⁶. -15 ° / s、 The maximum value at the switching moment is approximately -2.5 × 10⁻⁶. -34 ° / s, the angle of the platform relative to inertial space is approximately zero, where θ x The instantaneous maximum value at time zero when the circuit closes is approximately 8.0 × 10⁻⁶. -17 °、θ y The maximum value at the switching moment is approximately -3.5 × 10⁻⁶. -34 °.

[0230] When using the combined semi-stable partitioned discrete variable structure control method of this invention for control, the change process of the frame angle over time is as follows: Figure 16 As shown, the areas where the inner frame angle and the middle frame angle 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. Since there is no switching process during the 2.5s time period, the angular velocity of the platform relative to the inertial space is approximately zero, where, The maximum instantaneous value at time zero is approximately 2 × 10⁻⁶. -15 ° / s、 The instantaneous maximum value at time zero when the circuit closes is approximately 3.0 × 10⁻⁶. -34 ° / s; the angle between the platform and the inertial space is approximately zero, where θ x The instantaneous maximum value at time zero when the circuit closes is approximately 8.0 × 10⁻⁶. -18 °、θ yThe maximum value at the switching moment is approximately -3.4 × 10⁻⁶. -39 °.

[0231] By comparing the variable structure partition control with the combined semi-stable partition discrete variable structure control method of this invention, it can be seen that, due to the absence of a switching process, the overshoot of the table's angle and angular velocity relative to the inertial space depends only on the initial closure process, θ. y The significant reduction in the maximum value indicates that the method of the present invention has higher accuracy. Moreover, the combined semi-stable partitioned discrete variable structure control method of the present invention has the ability to avoid singular points, ensuring that the inertial platform has full attitude control capabilities.

[0232] This embodiment has the following advantages:

[0233] (1) The servo loop combination semi-stable partitioned discrete variable structure control method given in this embodiment has the advantage of less interference of the follower loop on the stage compared with the equal interval angle partitioned variable structure control method. Therefore, the decoupling method of this embodiment can enable the stage to maintain a high degree of accuracy relative to the inertial space.

[0234] (2) The servo loop combination semi-stable partitioned discrete variable structure control method given in this embodiment has the characteristic of smaller output energy compared with the equal interval angle partitioned variable structure control method, which is beneficial to saving control energy.

[0235] (3) The four-axis inertial stabilization platform system described in this embodiment has the characteristics of full attitude compared with the combined semi-stable partitioned discrete variable structure variable structure control method. It avoids the approximate simplification measures of the decoupler at singular points, which is beneficial to the adaptability of the four-axis inertial platform to the full attitude motion of the carrier.

[0236] Implementation Method 3:

[0237] This invention provides a servo loop-coordinated semi-stable partitioned discrete variable structure control method for a four-axis inertial stabilization platform, implemented based on a four-axis inertial stabilization platform system. By setting reasonable ranges for the inner frame angle and middle frame angle of the four-axis platform, the correlation between the stabilized angular velocity in the servo loop and the actuator is maximized while minimizing proximity to singular points, thereby minimizing the influence of the servo loop on the stabilization loop and ensuring that the switching control process balances overshoot and all attitudes. The 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 Yp1 Z p1 and the X coordinate system of the platform body p Y p Z p .

[0238] 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 .

[0239] like Figure 2 The processing flowchart shown illustrates the implementation steps of the servo loop cooperative semi-stable partitioned discrete variable structure control method for the four-axis inertial platform system of the present invention:

[0240] (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

[0241] (2) The relative rotation angles and angular velocities within 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotationzk and angular velocity

[0242] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0243] (3.1) Set the threshold angle β f The value (e.g., 15°);

[0244] (3.2) When β xk β yk Satisfy condition | secβ xk secβ yk |≤|cscβ xk |, or |secβ xk secβ yk |>|cscβ xk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows:

[0245]

[0246]

[0247]

[0248]

[0249] (3.3) When β xk β yk When condition (3.2) is not met, the specific calculation formula is as follows:

[0250]

[0251]

[0252]

[0253]

[0254] 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.

[0255] The aforementioned servo loop-coordinated semi-stable partitioned discrete variable structure control method for a four-axis inertial stabilized platform measures the relative rotation angle and angular velocity within the four-axis inertial stabilized platform system in step (2) using the following method:

[0256] 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 and angular velocity In Taiwan Sports 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 and angular velocity

[0257] In the above-mentioned four-axis inertial stabilization platform servo loop cooperative semi-stable partitioned discrete variable structure control method, in step (3), the rotation angle β yk The value range is -90 to 270°; rotation angle β zk β xk β yk′ The value range is -180 to 180°.

[0258] The angles that satisfy condition (3.2) include the following 6 closed regions:

[0259] (4.1) A closed region consisting of 5 straight lines and 1 curve, with equations of the lines and curve as follows:

[0260]

[0261] (4.2) A closed region consisting of 6 straight lines and 2 curves, the equations of the straight lines and curves are:

[0262]

[0263] (4.3) A closed region consisting of 5 straight lines and 1 curve. The equations of the straight lines and the curve are:

[0264]

[0265] (4.4) A closed region consisting of 5 straight lines and 1 curve, the equations of the straight lines and the curve are:

[0266]

[0267] (4.5) A closed region consisting of 6 straight lines and 2 curves, the equations of the straight lines and curves are:

[0268]

[0269] (4.6) A closed region consisting of 5 straight lines and 1 curve has the equations of the lines and the curve as follows:

[0270]

[0271] The angles that satisfy condition (3.3) include the following two closed regions:

[0272] (5.1) A closed region consisting of 8 straight lines and 4 curves, with the equations of the curves being:

[0273]

[0274] (5.2) A closed region consisting of 8 straight lines and 4 curves, with the equation of the curves being:

[0275]

[0276] To further illustrate that the decoupler of the present invention has the characteristic of minimum energy consumption, an embodiment is given below.

[0277] Example:

[0278] Reference "Variable Structure Partition Control of a Quad-Axis Gyroscope Stabilized Platform, Tsinghua University Journal Vol.50, No.7, 2010", the determined variable structure control region is as follows: Figure 3 As shown.

[0279] Let β yk′ β xk β yk β zk The initial values ​​are 0°, 38°, 90°, and 0° respectively. When using variable structure zoning control, the initial position is in region 3. Let the platform base angular velocity be...

[0280] The time-varying process of the frame angle controlled by variable structure zoning is as follows: Figure 20 As shown, the areas where the inner and outer frames 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. At 1.5s, the platform transitions from region 3 to region 1, and there is a shaking motion during the region switch. The platform's angular velocity is... The maximum instantaneous value at time zero when the circuit closes is approximately -309° / s. The maximum value at the switching moment is approximately -68.8° / 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 -2.3°, θ y The maximum value at the switching moment is approximately -0.65°.

[0281] When using the cooperative semi-stable partitioned discrete variable structure control method of this invention for control, the change process of the frame angle over time is as follows: Figure 24 As shown, the areas where the inner frame and middle frame angles are located are as follows: Figure 25 As 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. At 1.725s, the stage transitions from region 3 to region 1, and the stage shakes during the region switch. The stage's angular velocity is... The maximum instantaneous value at time zero when the circuit closes is approximately -240° / s. The maximum value at the switching moment is approximately -44.0° / 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 -1.8°, θ y The maximum value at the switching moment is approximately -0.42°.

[0282] By comparing the variable structure partition control with the cooperative semi-stable partition discrete variable structure control method of this invention, it can be seen that the angular velocity and angle of the platform are significantly reduced by the cooperative semi-stable partition discrete variable structure control method of this invention, indicating that the method of this invention has higher accuracy. Moreover, the cooperative semi-stable partition discrete variable structure control method of this invention has the ability to avoid singular points, ensuring that the inertial platform has full attitude control capabilities.

[0283] This embodiment has the following advantages:

[0284] (1) The servo loop cooperative semi-stable partitioned discrete variable structure control method given in this embodiment has the advantage of less interference of the follower loop on the stage compared with the equal interval angle partitioned variable structure control method. Therefore, the decoupling method of this embodiment can enable the stage to maintain a high degree of accuracy relative to the inertial space.

[0285] (2) The servo loop cooperative semi-stable partitioned discrete variable structure control method given in this embodiment has the characteristic of smaller output energy compared with the equal interval angle partitioned variable structure control method, which is beneficial to saving control energy.

[0286] (3) The four-axis inertial stabilization platform system described in this embodiment has the characteristics of full attitude compared with the cooperative semi-stable partitioned discrete variable structure variable structure control method. It avoids the approximate simplification measures of the decoupler at singular points, which is beneficial to the adaptability of the four-axis inertial platform to the full attitude motion of the carrier.

[0287] Implementation Method Four:

[0288] In engineering applications, to ensure the platform's stability relative to inertial space, limiting pins are installed on the inner frame axis to restrict the range of the inner frame's angle (generally not exceeding ±45°). When β xk When the angle is ±90°, the inner frame angle will change with the movement of the carrier and cannot be kept at zero. One solution is as follows: "Rotate the outer frame by 90° to bring the inner frame angle back to near zero, and at the same time move the middle frame away from the ±90° position, so that the three-frame four-axis platform can once again meet the working conditions of the traditional servo loop". See the literature "Research on the control strategy of servo frame of four-axis inertial platform, Navigation and Control, No. 4, 2017".

[0289] The present invention provides a servo loop locking-type partitioned discrete variable structure control method for a four-axis inertial stabilization platform, implemented based on a four-axis inertial stabilization platform system. By setting reasonable ranges for the inner frame angle and middle frame angle of the four-axis platform, the correlation between the stabilized angular velocity in the servo loop and the actuator is maximized while avoiding proximity to singular points, thereby minimizing the influence of the servo loop on the stabilization loop and enabling the switching control process to balance overshoot and full attitude.

[0290] This four-axis stabilized platform system includes a base, outer frame, middle frame, inner frame, and 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 .

[0291] 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 .

[0292] like Figure 28 The processing flowchart shown illustrates the following steps for implementing the servo loop locking partitioned discrete variable structure control method for the four-axis inertial platform system of this invention:

[0293] (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

[0294] (2) The relative rotation angles and angular velocities within the four-axis inertial stabilized platform system were measured, including: the Y-axis of the base around the outer frame's body coordinate system. p3 The angle β of the shaft rotation yk′ and angular velocity The outer frame around the middle frame's body coordinate system X p2 The angle β of the shaft rotation xk and angular velocity Y-axis of the middle frame around the inner frame body coordinate system p1 The angle β of the shaft rotation yk and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk ;

[0295] (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows:

[0296] (3.1) Set the threshold angle β f The value (e.g., 15°);

[0297] (3.2) When βxk β yk Meet the conditions And |sinβ xk |≥|sinβ f When |, the specific calculation formula is as follows:

[0298]

[0299]

[0300]

[0301]

[0302] (3.3) When β xk β yk Meet the conditions And |sinβ xk When |≥|sin46.457°|, the specific calculation formula is as follows:

[0303]

[0304]

[0305]

[0306]

[0307] (3.4) When β xk β yk When conditions (3.2) and (3.3) are not met, the specific calculation formula is as follows:

[0308]

[0309]

[0310]

[0311]

[0312] 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.

[0313] The aforementioned servo loop locking-type partitioned discrete variable structure control method for a four-axis inertial stabilization platform measures the relative rotation angle and angular velocity within the four-axis inertial stabilization platform system in step (2) using the following method:

[0314] Y in the base p3 An angle sensor is installed on the axis to measure the Y-axis of the base around the outer frame's coordinate system. p3 The angle β of the shaft rotation yk′ and angular velocity 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 and angular velocity Y in the inner frame 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 and angular velocity In Taiwan Sports 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 and angular velocity

[0315] In the above-mentioned servo loop locking partitioned discrete variable structure control method for a four-axis inertial stabilization platform, in step (3), the rotation angle β yk The value range is -90 to 270°; rotation angle β zk β xk β yk′ The value range is -180 to 180°.

[0316] The angles that satisfy condition (3.2) include the following 6 closed regions:

[0317] (4.1) A closed region consisting of 3 straight lines and 1 curve, with equations of the lines and curve as follows:

[0318]

[0319] (4.2) A closed region consisting of two straight lines and two curves, with equations of the lines and curves as follows:

[0320]

[0321] (4.3) A closed region consisting of 3 straight lines and 1 curve, with equations of the lines and curve as follows:

[0322]

[0323] (4.4) A closed region consisting of 3 straight lines and 1 curve, with equations of the lines and curve as follows:

[0324]

[0325] (4.5) A closed region consisting of two straight lines and two curves, the equations of the straight lines and curves are:

[0326]

[0327] (4.6) A closed region consisting of 3 straight lines and 1 curve has the equations of the lines and the curve as follows:

[0328]

[0329] The angles that satisfy condition (3.3) include the following four closed regions:

[0330] (5.1) A closed region consisting of two straight lines and two curves, with equations of the lines and curves as follows:

[0331]

[0332] (5.2) A closed region consisting of 2 straight lines and 4 curves, the equations of the straight lines and curves are:

[0333]

[0334] (5.3) A closed region consisting of 2 straight lines and 4 curves, the equations of the straight lines and curves are:

[0335]

[0336] (5.4) A closed region consisting of 2 straight lines and 4 curves, the equations of the straight lines and curves are:

[0337]

[0338] The angles that satisfy condition (3.4) include the following three closed regions:

[0339] (6.1) A closed region consisting of 8 straight lines and 4 curves, with equations of the lines and curves as follows:

[0340]

[0341] (6.2) A closed region consisting of 12 straight lines and 8 curves, with equations of the lines and curves as follows:

[0342]

[0343] as well as

[0344]

[0345] (6.3) A closed region consisting of 8 straight lines and 4 curves, the equations of the straight lines and curves are:

[0346]

[0347] To further illustrate that the decoupler of the present invention has the characteristic of minimum energy consumption, an embodiment is given below.

[0348] Example:

[0349] Reference "Research on Control Strategy of Four-Axis Inertial Platform Follower Frame, Navigation and Control, 2017, No. 4", defines the region for locking-type discrete variable structure control when the inner frame angle is limited, as follows: Figure 29 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.

[0350] 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...

[0351] 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 30 As shown, the areas where the inner and outer frames are located are as follows: Figure 31 As shown, the change of the angular velocity of the platform with time is as follows: Figure 32 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 33 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°.

[0352] When using the unrestricted locking partitioned discrete variable structure control method of this invention for control, the change process of the frame angle over time is as follows: Figure 34As shown, the areas where the inner frame and middle frame angles are located are as follows: Figure 35 As shown, the change of the angular velocity of the platform with time is as follows: Figure 36 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 37 As shown. At 0.9s, when entering region 1 from region 3, the angular velocity of the platform and the angle of the platform relative to the inertial space are close to zero, indicating that the platform does not shake during the region switch.

[0353] By comparing the locking-type variable structure partition control when the inner frame angle is limited with the locking-type partition discrete variable structure control method of the present invention when the inner frame angle is unrestricted, it can be seen that the angular velocity and angle of the platform controlled by the present invention are significantly reduced, indicating that the method of the present invention has higher accuracy. Moreover, the control method of the present invention has the ability to avoid singular points, ensuring that the inertial platform has full attitude control capabilities.

[0354] This embodiment has the following advantages:

[0355] (1) The servo loop locking partition discrete variable structure control method given in this embodiment has the characteristic of smooth area switching compared with the locking partition variable structure control method when the inner frame corner is limited, so that the platform body no longer shakes. Therefore, the control method of this embodiment can enable the platform body to maintain a high degree of precision relative to the inertial space.

[0356] (2) The servo loop locking partition discrete variable structure control method given in this embodiment has the characteristic that the inner frame is not subject to the forced constraints of hardware (limiting pins) and software (thresholds) compared with the locking partition variable structure control method when the inner frame angle is limited, and realizes the non-singular full attitude control of the inertial platform under arbitrary frame angle conditions.

[0357] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0358] 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 hybrid discrete variable structure control method for a four-axis inertial stabilization platform using a servo loop, characterized in that, include: (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 (2) Measure the X coordinate system of the outer frame around the middle frame body. 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows: (3.1) Set the threshold angle β f The value; (3.2) When β xk β yk Satisfy condition |cosβ xk |≥|sinβ xk cosβ yk |and|cosβ xk |≥|sinβ yk |, or |sinβ yk |>|cosβ xk |and|sinβ yk |≥|sinβ xk cosβ yk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows: (3.3) When β xk β yk The condition in (3.2) is not satisfied, but the condition |sinβ is satisfied. xk cosβ yk |≥|sinβ yk When |, the specific calculation formula is as follows: (3.4) When β xk β yk When conditions (3.2) and (3.3) are not met, 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.

2. The discrete variable structure control method according to claim 1, characterized in that, The angles that satisfy step (3.2) include the following 6 closed regions: (2.1) A closed region consisting of 7 straight lines and 1 curve, with equations of the lines and curve as follows: (2.2) A closed region consisting of 10 straight lines and 2 curves, with equations of the lines and curves as follows: (2.3) A closed region consisting of 7 straight lines and 1 curve, the equations of the straight lines and the curve are: (2.4) A closed region consisting of 7 straight lines and 1 curve, the equations of the straight lines and the curve are: (2.5) A closed region consisting of 10 straight lines and 2 curves, the equations of the straight lines and curves are: (2.6) A closed region consisting of 7 straight lines and 1 curve, the equations of the straight lines and the curve are:

3. The discrete variable structure control method according to claim 1, characterized in that, The angles that satisfy step (3.3) include the following four closed regions: (3.1) A closed region consisting of 4 curves, the equations of which are: (3.2) The closed region is formed by four curves, and the equations of the curves are: (3.3) The closed region is formed by four curves, and the equations of the curves are: (3.4) The closed region is formed by four curves, and the equations of the curves are:

4. The discrete variable structure control method according to claim 1, characterized in that, The angles that satisfy step (3.4) include the following 6 closed regions: (4.1) A closed region consisting of 5 straight lines and 1 curve, with equations of the lines and curve as follows: (4.2) A closed region consisting of 5 straight lines and 1 curve, with equations of the lines and curve as follows: (4.3) A closed region consisting of 6 straight lines and 2 curves, the equations of the straight lines and curves are: (4.4) A closed region consisting of 6 straight lines and 2 curves, the equations of the straight lines and curves are: (4.5) A closed region consisting of 5 straight lines and 1 curve, the equations of the straight lines and the curve are: (4.6) A closed region consisting of 5 straight lines and 1 curve has the equations of the lines and the curve as follows:

5. A semi-stable partitioned discrete variable structure control method for a four-axis inertial stabilization platform using a combined servo loop, characterized in that... include: (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 (2) Measure the X coordinate system of the outer frame around the middle frame body. 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows: (3.1) Set the threshold angle β f The value; (3.2) When β xk β yk Satisfy condition |cosβ xk |≥|sinβ xk cosβ yk |and|cosβ xk |≥|sinβ yk |, or |sinβ yk |>|cosβ xk |and|sinβ yk |≥|sinβ xk cosβ yk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows: (3.3) When β xk β yk When condition (3.2) is not met, 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.

6. The discrete variable structure control method according to claim 5, characterized in that, The angles that satisfy step (3.2) include the following 6 closed regions: (6.1) A closed region consisting of 7 straight lines and 1 curve, with equations of the lines and curve as follows: (6.2) A closed region consisting of 10 straight lines and 2 curves, with equations of the lines and curves as follows: (6.3) A closed region consisting of 7 straight lines and 1 curve, with equations of the lines and curve as follows: (6.4) A closed region consisting of 7 straight lines and 1 curve. The equations of the straight lines and the curve are: (6.5) A closed region consisting of 10 straight lines and 2 curves, with equations of the lines and curves as follows: (6.6) A closed region consisting of 7 straight lines and 1 curve has the equations of the lines and the curve as follows:

7. The discrete variable structure control method according to claim 5, characterized in that, The angles that satisfy step (3.3) include the following two closed regions: (7.1) A closed region consisting of 16 straight lines and 4 curves, with the equations of the curves being: (7.2) A closed region consisting of 16 straight lines and 4 curves, with the equations of the curves being:

8. A servo loop-coordinated semi-stable partitioned discrete variable structure control method for a four-axis inertial stabilization platform, characterized in that, include: (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 (2) Measure the X coordinate system of the outer frame around the middle frame body. 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 and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk and angular velocity (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows: (3.1) Set the threshold angle β f The value; (3.2) When β xk β yk Satisfy condition | secβ xk secβ yk |≤|cscβ xk |, or |secβ xk secβ yk |>|cscβ xk |and|sinβ xk |<|sinβ f When |, the specific calculation formula is as follows: (3.3) When β xk β yk When condition (3.2) is not met, 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.

9. The discrete variable structure control method according to claim 8, characterized in that, The angles that satisfy step (3.2) include the following 6 closed regions: (9.1) A closed region consisting of 5 straight lines and 1 curve has the equations of the lines and the curve as follows: (9.2) A closed region consisting of 6 straight lines and 2 curves, with equations of the lines and curves as follows: (9.3) A closed region consisting of 5 straight lines and 1 curve has the equations of the lines and the curve as follows: (9.4) A closed region consisting of 5 straight lines and 1 curve has the equations of the lines and the curve as follows: (9.5) A closed region consisting of 6 straight lines and 2 curves has the equations of the lines and curves as follows: (9.6) A closed region consisting of 5 straight lines and 1 curve has the equations of the lines and the curve as follows:

10. The discrete variable structure control method according to claim 8, characterized in that, The angles that satisfy step (3.3) include the following two closed regions: (10.1) A closed region consisting of 8 straight lines and 4 curves has the following equations: (10.2) A closed region consisting of 8 straight lines and 4 curves, with the equation of the curves being:

11. A servo loop locking-type partitioned discrete variable structure control method for a four-axis inertial stabilization platform, characterized in that, include: (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 (2) Measure the Y-axis of the base around the outer frame coordinate system. p3 The angle β of the shaft rotation yk′ and angular velocity The outer frame around the middle frame's body coordinate system X p2 The angle β of the shaft rotation xk and angular velocity Y-axis of the middle frame around the inner frame body coordinate system p1 The angle β of the shaft rotation yk and angular velocity Z-axis of the inner frame around the body coordinate system p The angle β of the shaft rotation zk ; (3) Calculate the rotational angular velocities of the platform, inner frame, middle frame, and outer frame. The process is as follows: (3.1) Set the threshold angle β f The value; (3.2) When β xk β yk Meet the conditions And |sinβ xk |≥|sinβ f When |, the specific calculation formula is as follows: (3.3) When β xk β yk Meet the conditions And |sinβ xk When |≥|sin46.457°|, the specific calculation formula is as follows: (3.4) When β xk β yk When conditions (3.2) and (3.3) are not met, 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.

12. The discrete variable structure control method according to claim 11, characterized in that, The angles that satisfy step (3.2) include the following 6 closed regions: (12.1) A closed region is formed by three straight lines and one curve. The equations of the straight lines and the curve are: (12.2) A closed region is formed by two straight lines and two curves. The equations of the straight lines and curves are: (12.3) A closed region consisting of 3 straight lines and 1 curve has the equations of the lines and the curve as follows: (12.4) A closed region is formed by three straight lines and one curve. The equations of the straight lines and the curve are: (12.5) A closed region is formed by two straight lines and two curves. The equations of the straight lines and curves are: (12.6) A closed region is formed by three straight lines and one curve. The equations of the straight lines and the curve are:

13. The discrete variable structure control method according to claim 11, characterized in that, The angles that satisfy step (3.3) include the following four closed regions: (13.1) A closed region is formed by two straight lines and two curves. The equations of the straight lines and curves are: (13.2) A closed region consisting of 2 straight lines and 4 curves, with equations of the straight lines and curves as follows: (13.3) A closed region consisting of 2 straight lines and 4 curves, with equations of the lines and curves as follows: (13.4) A closed region consisting of 2 straight lines and 4 curves has the equations of the straight lines and curves as follows:

14. The discrete variable structure control method according to claim 11, characterized in that, The angles that satisfy step (3.4) include the following three closed regions: (14.1) A closed region consisting of 8 straight lines and 4 curves has the equations of the lines and curves as follows: (14.2) A closed region consisting of 12 straight lines and 8 curves, the equations of the straight lines and curves are: as well as (14.3) A closed region consisting of 8 straight lines and 4 curves has the equations of the lines and curves as follows:

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