Method and device for automatically correcting zero coordinate of hinge point of swing table with series-parallel connection structure
By obtaining the length of the driving rod by moving the swing table to multiple attitude angles and iteratively correcting the zero-position coordinate of the upper hinge point using partial differential equations, the problem of decreased control accuracy of the swing table under different loads is solved, high-precision automatic correction is achieved, and the applicability and reliability of the swing table's control system are improved.
Patent Information
- Application Number
- CN202510802685.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-16
- Publication Date
- 2025-09-26
AI Technical Summary
In the prior art, when the swing platform carries different loads, the zero-position coordinate of the hinge point on the driving rod changes due to the deformation of the platform structure, resulting in a decrease in control accuracy and servo failure. The existing correction method is costly or has low accuracy.
By controlling the swing table to move to three different attitude angles under load, the actual length of the driving rod is obtained, the difference between the converted coordinates of the lower hinge point and the theoretical length is calculated, and the partial differential equation is used to solve and correct the zero-position coordinates of the upper hinge point. The error is iterated until the error is less than the set threshold value, thus achieving automatic high-precision correction.
High-precision correction of the zero-position coordinate of the upper hinge point can be achieved without increasing hardware costs, solving the problem of parallel control of driving rods under different loads and improving the control accuracy and reliability of the swing platform.
Smart Images
Figure CN120704409A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of swing stage control, and in particular relates to a method and a device for automatically correcting the zero-position coordinates of hinge points of a series-parallel structure swing stage. Background Art
[0002] A sway platform is a spatial motion mechanism widely used to simulate the motion of ships or vehicles, and has high application value in both defense and civilian applications. A series-parallel sway platform features a series-connected pitch and roll body. The pitch body is mounted on a fixed base via a pitch bearing for pitch motion, while the roll body is mounted on the pitch body via a roll bearing for roll motion. The load is mounted on the roll body. The platform is driven by multiple drive rods connected in parallel. These drive rods can be hydraulic or electric cylinders. The lower hinge of each drive rod is mounted on the fixed base, and the upper hinge of each drive rod is mounted on the roll body. To control the sway angle of a sway platform, the inverse position method is typically used. This method derives the length command for each drive rod based on the sway attitude angle and the zero-position coordinates of the upper and lower hinge points of each drive rod. This method then uses real-time closed-loop control to extend and retract each drive rod according to the length command, thereby controlling the sway angle. Therefore, the zero-position coordinates of the upper and lower hinge points of each drive rod are the basis for determining the length of each drive rod. However, in actual engineering, when the swing table carries different loads, the table structure will have different degrees of deformation. Since the upper hinge is installed on the table structure, this structural deformation will change the zero-position coordinate of the upper hinge of the driving rod, resulting in inconsistency between the theoretical length of the driving rod obtained by analysis and the actual length of the driving rod, causing servo conflicts and abnormal stress on the table in the parallel control of each driving rod, which in turn affects the control accuracy and test safety.
[0003] Therefore, in order to ensure the control accuracy of the swing table, it is necessary to correct the zero-position coordinates of the upper hinge point. In the prior art, the zero-position coordinates of the upper hinge points of each driving rod are usually re-measured or the zero-position coordinates of the upper hinge points are simulated and corrected by establishing a deformation model of the table structure under different loads. The method of re-measuring the zero-position coordinates of the upper hinge point requires re-establishing the measurement coordinate system, measuring the coordinates of the upper hinge point using a laser tracker, and updating the program setting value. The test cost is high, the difficulty is great, and the timeliness and use effect are poor. The method of simulating and correcting the zero-position coordinates of the upper hinge point by establishing a deformation model of the table structure under different loads requires improving the performance and computing power of the hardware equipment of the swing table control system, and the confidence of the model is often not high, resulting in low correction accuracy of the zero-position coordinates of the upper hinge point. Summary of the Invention
[0004] The purpose of the present invention is to provide a method and device for automatically correcting the zero-position coordinates of the hinge points of a series-parallel structure swing platform, so as to provide a low-cost and high-accuracy automatic correction method for the zero-position coordinates of the hinge points.
[0005] In order to solve the above technical problems, the present invention provides a method for automatically correcting the zero-position coordinates of the hinge points of a series-parallel structure swing platform, which is characterized by comprising:
[0006] Under load, the swing platform is controlled to move to three different attitude angles, and the actual lengths of the driving rods under the three attitude angles are obtained;
[0007] Calculate the three sets of converted coordinates of the lower hinge points of each driving rod after the swing platform rotates three sets of attitude angles respectively;
[0008] Calculate the theoretical length of each driving rod under the three sets of attitude angles, establish an equation between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge zero coordinate of the driving rod, and solve the equation to determine the corrected upper hinge zero coordinate of each driving rod under the load state, so that the difference between the theoretical length of the driving rod and the corresponding actual length meets the accuracy requirements; among which, the theoretical length of the driving rod is determined based on the corrected upper hinge zero coordinate and the lower hinge conversion coordinate of the driving rod.
[0009] Furthermore, the method adopted for solving the equation is to use the partial differential of the equation with respect to the corrected zero-position coordinate of the upper hinge point.
[0010] Furthermore, the process of solving the equation for the partial differential of the corrected upper hinge zero coordinate using the equation is as follows: the error amount is calculated using the error amount calculation formula; in the next iteration, the upper hinge zero coordinate is the sum of the error amount in the previous iteration and the corrected upper hinge zero coordinate; until the error amount is less than the set threshold value, the iteration process is terminated, and the corrected upper hinge zero coordinate corresponding to the last iteration is used as the corrected upper hinge zero coordinate of each driving rod under the corresponding load state; in the first iteration, the original upper hinge zero coordinate is used as the corrected upper hinge zero coordinate to calculate the corresponding error amount; the threshold value is the accuracy value that makes the difference between the theoretical length of the driving rod and the corresponding actual length meet the accuracy requirements; the error amount calculation formula is:
[0011]
[0012] Among them, q 1j ,q 2j and q 3j are the errors of the j-th driving rod corresponding to the three groups of attitude angles; f 1j 、f 2j and f 3j are the differences between the square of the theoretical length and the square of the actual length of the j-th driving rod corresponding to the three groups of attitude angles; X aj 、Y aj and Z ajare the X-axis value, Y-axis value, and Z-axis value of the corrected upper hinge zero position coordinates of the j-th driving rod.
[0013] Furthermore, the equation between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge zero coordinate of the driving rod is:
[0014]
[0015] Among them, u 1j 、u 2j and u 3j are the X-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, v 1j 、v 2j and v 3j are the Y-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, w 1j 、w 2j and w 3j are the Z-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, L 1j , L 2j and L 3j are the actual lengths of the j-th driving rod corresponding to the three sets of attitude angles.
[0016] Furthermore, the swing platform is controlled to move to three different attitude angles respectively, and the angle values of the attitude angles are near zero. Near zero means that the angle value is greater than zero and less than a first set value.
[0017] The beneficial effects of the above technical solution are as follows: the present invention is a pioneering invention. In response to the load-induced deformation of the platform structure, the swing platform is controlled to move to three sets of attitude angles, and the lower hinge point zero position coordinates corresponding to each driving rod under the load are converted to the three sets of lower hinge point conversion coordinates corresponding to each driving rod when the three sets of attitude angles are used as the zero point. The corrected upper hinge point zero position coordinates are used as unknown quantities. The theoretical length of the driving rod is determined based on the corrected upper hinge point zero position coordinates and the lower hinge point conversion coordinates of the driving rod. An equation is established between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge point zero position coordinate of the driving rod. The equation is solved to obtain the corrected upper hinge point zero position coordinates of each driving rod under the load state, so that the difference between the theoretical length and the corresponding actual length of the driving rod meets the accuracy requirements, thereby automatically correcting the upper hinge point zero position coordinate value of the driving rod. Without increasing hardware cost, the upper hinge point zero position coordinate can be corrected with high precision, solving the problem of parallel control of multiple driving rods caused by the change of the upper hinge point zero position coordinates under different loads, ensuring the control accuracy of the swing platform, and improving the applicability and reliability of the swing platform control system.
[0018] In order to solve the above technical problems, the present invention also provides an automatic correction device for the zero-position coordinates of the hinge points of a series-parallel structure swing platform, including a processor, which is used to control the swing platform to move to three different posture angles under a load state, and obtain the actual length of each driving rod under the three posture angles; calculate the three sets of lower hinge conversion coordinates corresponding to the zero-position coordinates of the lower hinge points of each driving rod after the swing platform body rotates through the three posture angles; calculate the theoretical length of each driving rod under the three posture angles, establish an equation between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge zero-position coordinates of the driving rod, solve the equation to determine the corrected upper hinge zero-position coordinates of each driving rod under the load state, so that the difference between the theoretical length of the driving rod and the corresponding actual length meets the accuracy requirements; wherein, the theoretical length of the driving rod is determined based on the corrected upper hinge zero-position coordinates of the driving rod and the lower hinge conversion coordinates.
[0019] Furthermore, the processor solves the equation by using the partial differential of the equation with respect to the corrected zero-position coordinate of the upper hinge point.
[0020] Furthermore, the process of solving the equation for the partial differential of the corrected upper hinge zero coordinate using the equation is as follows: the error amount is calculated using the error amount calculation formula; in the next iteration, the upper hinge zero coordinate is the sum of the error amount in the previous iteration and the corrected upper hinge zero coordinate; until the error amount is less than the set threshold value, the iteration process is terminated, and the corrected upper hinge zero coordinate corresponding to the last iteration is used as the corrected upper hinge zero coordinate of each driving rod under the corresponding load state; in the first iteration, the original upper hinge zero coordinate is used as the corrected upper hinge zero coordinate to calculate the corresponding error amount; the threshold value is the accuracy value that makes the difference between the theoretical length of the driving rod and the corresponding actual length meet the accuracy requirements; the error amount calculation formula is:
[0021]
[0022] Among them, q 1j ,q 2j and q 3j are the errors of the j-th driving rod corresponding to the three groups of attitude angles; f 1j 、f 2j and f 3j are the differences between the square of the theoretical length and the square of the actual length of the j-th driving rod corresponding to the three groups of attitude angles; X aj 、Y aj and Z aj are the X-axis value, Y-axis value, and Z-axis value of the corrected upper hinge zero position coordinates of the j-th driving rod.
[0023] Furthermore, the swing platform is controlled to move to three different attitude angles respectively, and the angle values of the attitude angles are near zero. Near zero means that the angle value is greater than zero and less than a first set value.
[0024] Furthermore, the processor is a motion controller in a series-parallel structure swing platform control system.
[0025] The beneficial effects of the above technical solution are as follows: the present invention is a pioneering invention. In response to the load-induced deformation of the platform structure, the swing platform is controlled to move to three sets of attitude angles, and the lower hinge point zero position coordinates corresponding to each driving rod under the load are converted to the three sets of lower hinge point conversion coordinates corresponding to each driving rod when the three sets of attitude angles are used as the zero point. The corrected upper hinge point zero position coordinates are used as unknown quantities. The theoretical length of the driving rod is determined based on the corrected upper hinge point zero position coordinates and the lower hinge point conversion coordinates of the driving rod. An equation is established between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge point zero position coordinate of the driving rod. The equation is solved to obtain the corrected upper hinge point zero position coordinates of each driving rod under the load state, so that the difference between the theoretical length and the corresponding actual length of the driving rod meets the accuracy requirements, thereby automatically correcting the upper hinge point zero position coordinate value of the driving rod. Without increasing hardware cost, the upper hinge point zero position coordinate can be corrected with high precision, solving the problem of parallel control of multiple driving rods caused by the change of the upper hinge point zero position coordinates under different loads, ensuring the control accuracy of the swing platform, and improving the applicability and reliability of the swing platform control system. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 Schematic diagram of the series-parallel structure swing platform structure of the method implementation method of the present invention;
[0027] Figure 2 This is a flow chart of automatic correction of the zero-position coordinates of the hinge points of a series-parallel structure swing platform according to the method implementation mode of the present invention;
[0028] Figure 3 It is an iterative calculation flow chart of an embodiment of the method of the present invention;
[0029] Reference numerals: 1 - pitch body; 2 - roll body; 3 - driving rod. DETAILED DESCRIPTION
[0030] In order to make the objectives, technical solutions and advantages of the present invention more clear, the specific embodiments of the present invention are further described below with reference to the accompanying drawings.
[0031] The present invention uses the length value of the driving rod at different attitude angles of the rocking platform under load to automatically correct the upper hinge point zero position coordinate value of the driving rod, without increasing hardware cost and capable of performing high-precision correction of the upper hinge point zero position coordinate.
[0032] Method implementation
[0033] The present invention provides a method for automatically correcting the zero-position coordinates of the hinge points of a series-parallel structure swing platform. The method is applicable to correcting the zero-position coordinates of the upper hinge points of series-parallel structure swing platforms with different drive rod forms and different numbers of drive rods. The drive rod forms include hydraulic cylinders and electric cylinders. The structure of the series-parallel structure swing platform is as follows: Figure 1 As shown, it includes a pitching body 1, a rolling body 2 and a driving rod 3. Among them, the pitching body and the rolling body adopt a series structure, and multiple driving rods are driven in parallel. The automatic correction method of the zero position coordinate of the hinge point of the series-parallel structure swing platform of the present invention is as follows Figure 2 As shown, the specific process is as follows:
[0034] 1. Under load, control the swing platform to move to three different attitude angles and obtain the actual length of each driving rod at the three attitude angles.
[0035] Specifically, when the swing platform carries a load that causes the platform structure to deform, under the load state, the driving rod is controlled to extend and retract, so that the swing platform moves to three different posture angles, and the three groups of posture angle data are recorded (P i 、R i ), obtain the actual length L of each driving rod under three sets of attitude angles ij Among them, P i represents the pitch attitude angle of the i-th group of attitude angles, R i represents the roll attitude angle of the i-th group of attitude angles, L ij The actual length of the jth driving rod corresponding to the i-th group of attitude angles. j = 1 to m, where m is the number of driving rods and i = 1 to 3.
[0036] The following is an explanation of the automatic correction process of the zero-position coordinates of the hinge point of the present invention. The three groups of attitude angle data are recorded as (P1, R1), (P2, R2) and (P3, R3), and the actual lengths of the three groups of driving rods corresponding to the three groups of attitude angles are recorded as L. 1j , L 2j and L 3j .
[0037] The swing stage is controlled to move to three different attitude angles, each of which is near zero. Near zero means the angle is greater than zero and less than a first set value. The first set value is an angle value that provides high correction accuracy and is easy to calculate, such as 0.5 degrees.
[0038] 2. Calculate the three sets of converted coordinates of the lower hinge points corresponding to the zero-position coordinates of the lower hinge points of each driving rod after the swing platform body rotates through three sets of attitude angles.
[0039] The zero position coordinate of the upper hinge point of the swing table is (X ’ aj 、Y’ aj , Z ’ aj ), that is, the original upper hinge zero coordinate without correction, the lower hinge zero coordinate set by the swing table is (X bj 、Y bj , Z bj ), calculate the zero position coordinates (X bj 、Y bj , Z bj ) After the rocking platform rotates (P1, R1), (P2, R2) and (P3, R3) attitude angles respectively, the corresponding three sets of lower hinge point transformation coordinates (u 1j 、v 1j 、w 1j )、(u 2j 、v 2j 、w 2j )、(u 3j 、v 3j 、w 3j ). The coordinate transformation formula is as follows:
[0040]
[0041] Among them, u ij is the X-axis value of the lower hinge point of the j-th driving rod in the i-th group of attitude angles, v ij is the Y-axis value of the lower hinge point of the j-th driving rod in the transformed coordinates corresponding to the i-th group of attitude angles, w ij is the Z-axis value of the lower hinge point conversion coordinate of the j-th driving rod corresponding to the i-th group of attitude angles, A is the roll conversion matrix, B is the pitch conversion matrix, u 1j 、u 2j and u 3j are the X-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, v 1j 、v 2j and v 3j are the Y-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, w 1j 、w 2j and w 3j The Z-axis value of the lower hinge point of the j-th driving rod in the three groups of attitude angles, bj 、Y bj and Z bj are the X-axis value, Y-axis value, and Z-axis value of the zero position coordinate of the lower hinge point of the j-th driving rod, respectively.
[0042] 3. Calculate the theoretical length of each drive rod under the three sets of attitude angles, establish an equation between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge point zero coordinate of the drive rod, and solve the equation to determine the corrected upper hinge point zero coordinate of each drive rod under load, so that the difference between the theoretical length of the drive rod and the corresponding actual length meets the accuracy requirements.
[0043] Specifically, the partial differential of the equation for the corrected upper hinge point zero position coordinate is used to solve the equation, thereby obtaining the corrected upper hinge point zero position coordinate of each driving rod under the corresponding load state.
[0044] The theoretical length of the driving rod is determined based on the corrected zero coordinates of the upper hinge point and the transformed coordinates of the lower hinge point. In one embodiment, the theoretical length of the driving rod is calculated according to the Euclidean distance formula. Since the square root of the theoretical length may not be an integer, the calculation is more complicated in the subsequent solution process. Therefore, in a preferred embodiment, the difference used in establishing the equation is the difference between the square of the theoretical length of each driving rod and the square of the actual length. 1j , the equation is:
[0045]
[0046] Among them, f 1j 、f 2j and f 3j are the differences between the square of the theoretical length and the square of the actual length of the j-th driving rod corresponding to the three groups of attitude angles, X aj 、Y aj and Z aj are the X-axis value, Y-axis value, and Z-axis value of the corrected upper hinge zero position coordinates of the j-th driving rod.
[0047] Use the difference to solve the equation by partial differential of the zero coordinate of the upper hinge point after correction. The solution process is as follows: Figure 3 As shown, the error amount q is calculated using the error amount calculation formula ij , the error calculation formula is:
[0048]
[0049] Among them, q 1j ,q 2j and q 3j are the errors of the j-th driving rod corresponding to the three sets of attitude angles.
[0050] In the next iteration, the zero-position coordinate of the upper hinge point is the sum of the error amount in the previous iteration and the corrected zero-position coordinate of the upper hinge point. The iteration process ends until the error amount is less than the set threshold value. The corrected zero-position coordinate of the upper hinge point corresponding to the last iteration is used as the corrected zero-position coordinate of the upper hinge point of each driving rod under the corresponding load state.
[0051] Specifically, in the first iteration, the original upper hinge zero coordinate is used as the corrected upper hinge zero coordinate to calculate the error q of the first iteration. 1j , in the second iteration, q 1j Superimpose the corrected upper hinge zero coordinates of the previous iteration and calculate the error q of the second iteration 2j , that is, X aj =X aj +q 1j , Y aj =Y aj +q 2j , Z aj =Z aj +q 3j , iterate according to this method until q ij (i=1,2,3) value is less than the required threshold value Q ij , ending the iteration process. The corrected upper hinge zero coordinate corresponding to the last iteration is used as the corrected upper hinge zero coordinate of each drive rod under the corresponding load state. The threshold value is the accuracy value that ensures that the difference between the theoretical length of the drive rod and the corresponding actual length meets the accuracy requirements. It is set according to the control accuracy of the drive rod and is generally a few millimeters.
[0052] The rocking platform is controlled by using the corrected upper hinge point zero position coordinate corresponding to the last iteration instead of the original upper hinge point zero position coordinate.
[0053] Device implementation method
[0054] The present invention provides an automatic correction device for the zero-position coordinates of the hinge points of a series-parallel structure swing platform, including a processor, which is used to determine the corrected zero-position coordinates of the upper hinge points of each driving rod under the corresponding load state according to the automatic correction method for the zero-position coordinates of the hinge points of a series-parallel structure swing platform introduced in the above method implementation method.
[0055] The hardware equipment of the swing platform control system includes an inertial navigation system, an attitude acquisition module and a motion controller, wherein the inertial navigation system is installed on the upper surface of the swing platform body and is used to measure the roll attitude angle and pitch attitude angle in real time; the attitude acquisition module is used to receive the swing attitude data sent by the inertial navigation system in real time and forward it to the outside through different interfaces; the motion controller receives the attitude data and the feedback length of the drive rod sent by the attitude acquisition module, and completes the real-time position inverse solution and the closed-loop control of the drive rod length. Therefore, the processor in the present invention can be a motion controller in the control system of the series-parallel structure swing platform, so that the upper hinge coordinate value of the drive rod is automatically corrected by measuring the different attitude angle values of the platform body and the length values of the drive rod without increasing the hardware cost, thereby solving the problem of parallel control of multiple drive rods caused by the change of the zero-position hinge coordinate under different loads, ensuring the control accuracy of the swing platform, and improving the applicability and reliability. At this time, the automatic correction process of the zero-position coordinate of the hinge of the series-parallel structure swing platform is as follows:
[0056] Under load, the motion controller controls the extension and retraction of the driving rod in an open-loop state, controls the swing platform to move to three different attitude angles, and obtains the actual length of each driving rod under the three attitude angles.
[0057] The inertial navigation system records these three sets of attitude angle data (P i 、R i ), and sends the attitude angle data to the attitude acquisition module, which sends the attitude angle data to the motion controller. The motion controller calculates the actual length L of each driving rod under the three groups of attitude angles. ij , three sets of attitude angle data (P i 、R i ) and the set upper hinge point zero coordinates and lower hinge point zero coordinates, and determine the corrected upper hinge point zero coordinates. Specifically, the following steps are included:
[0058] Firstly, the three sets of converted coordinates of the lower hinge points corresponding to the zero position coordinates of the lower hinge points of each driving rod are calculated after the rocking platform body rotates through three sets of attitude angles respectively.
[0059] The zero position coordinate of the upper hinge point of the swing table is (X ’ aj 、Y ’ aj , Z ’ aj ), that is, the original upper hinge zero coordinate without correction, the lower hinge zero coordinate set by the swing table is (X bj 、Y bj , Z bj ), calculate the zero position coordinates (X bj 、Y bj , Z bj) After the rocking platform rotates (P1, R1), (P2, R2) and (P3, R3) attitude angles respectively, the corresponding three sets of lower hinge point transformation coordinates (u 1j 、v 1j 、w 1j )、(u 2j 、v 2j 、w 2j )、(u 3j 、v 3j 、w 3j ). The coordinate transformation formula is as follows:
[0060]
[0061] Among them, u ij is the X-axis value of the lower hinge point of the j-th driving rod in the i-th group of attitude angles, v ij is the Y-axis value of the lower hinge point of the j-th driving rod in the transformed coordinates corresponding to the i-th group of attitude angles, w ij is the Z-axis value of the lower hinge point conversion coordinate of the j-th driving rod corresponding to the i-th group of attitude angles, A is the roll conversion matrix, B is the pitch conversion matrix, u 1j 、u 2j and u 3j are the X-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, v 1j 、v 2j and v 3j are the Y-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, w 1j 、w 2j and w 3j The Z-axis value of the lower hinge point of the j-th driving rod in the three groups of attitude angles, bj 、Y bj and Z bj are the X-axis value, Y-axis value, and Z-axis value of the zero position coordinate of the lower hinge point of the j-th driving rod, respectively.
[0062] Then, the theoretical length of each driving rod under the three sets of attitude angles is calculated, and an equation is established between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge point zero coordinate of the driving rod. The equation is solved to determine the corrected upper hinge point zero coordinate of each driving rod under the load state, so that the difference between the theoretical length of the driving rod and the corresponding actual length meets the accuracy requirements.
[0063] Specifically, the partial differential of the corrected upper hinge point zero position coordinate is used to solve the equation, and the corrected upper hinge point zero position coordinate of each driving rod under the corresponding load state is obtained.
[0064] The theoretical length of the driving rod is determined based on the corrected zero coordinates of the upper hinge point and the transformed coordinates of the lower hinge point. In one embodiment, the theoretical length of the driving rod is calculated according to the Euclidean distance formula. Since the square root of the theoretical length may not be an integer, the calculation is more complicated in the subsequent solution process. Therefore, in a preferred embodiment, the difference used in establishing the equation is the difference between the square of the theoretical length of each driving rod and the square of the actual length. 1j , the equation is:
[0065]
[0066] Among them, f 1j 、f 2j and f 3j are the differences between the square of the theoretical length and the square of the actual length of the j-th driving rod corresponding to the three groups of attitude angles, X aj 、Y aj and Z aj are the X-axis value, Y-axis value, and Z-axis value of the corrected upper hinge zero position coordinates of the j-th driving rod.
[0067] The equation is solved by using the partial differential of the zero coordinate of the upper hinge point after correction. The principle is to calculate the error amount q using the error calculation formula ij , the error calculation formula is:
[0068]
[0069] Among them, q 1j ,q 2j and q 3j are the errors of the j-th driving rod corresponding to the three sets of attitude angles.
[0070] In the next iteration, the zero-position coordinate of the upper hinge point is the sum of the error amount in the previous iteration and the corrected zero-position coordinate of the upper hinge point. The iteration process ends until the error amount is less than the set threshold value. The corrected zero-position coordinate of the upper hinge point corresponding to the last iteration is used as the corrected zero-position coordinate of the upper hinge point of each driving rod under the corresponding load state.
[0071] Specifically, in the first iteration, the original upper hinge zero coordinate is used as the corrected upper hinge zero coordinate to calculate the error q of the first iteration. 1j , in the second iteration, q 1j Superimpose the corrected upper hinge zero coordinates of the previous iteration and calculate the error q of the second iteration 2j , that is, X aj =X aj +q 1j , Y aj =Y aj +q2j , Z aj =Z aj +q 3j , iterate according to this method until q ij (i=1,2,3) value is less than the required threshold value Q ij , ending the iteration process. The corrected upper hinge zero coordinate corresponding to the last iteration is used as the corrected upper hinge zero coordinate of each drive rod under the corresponding load state. The threshold value is the accuracy value that ensures that the difference between the theoretical length of the drive rod and the corresponding actual length meets the accuracy requirements. It is set according to the control accuracy of the drive rod and is generally a few millimeters.
Claims
1. A method for automatically correcting the zero-position coordinates of the hinge points of a series-parallel structure swing platform, characterized in that: include: Under load, the swing platform is controlled to move to three different attitude angles, and the actual lengths of the driving rods under the three attitude angles are obtained; Calculate the three sets of converted coordinates of the lower hinge points of each driving rod after the swing platform rotates three sets of attitude angles respectively; Calculate the theoretical length of each driving rod under the three sets of attitude angles, establish an equation between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge zero coordinate of the driving rod, and solve the equation to determine the corrected upper hinge zero coordinate of each driving rod under the load state, so that the difference between the theoretical length of the driving rod and the corresponding actual length meets the accuracy requirements; among which, the theoretical length of the driving rod is determined based on the corrected upper hinge zero coordinate and the lower hinge conversion coordinate of the driving rod.
2. The method for automatically correcting the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 1 is characterized in that: The method used to solve the equation is to use the partial differential of the equation with respect to the corrected zero coordinate of the upper hinge point.
3. The method for automatically correcting the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 2, characterized in that: The process of solving the equation for the partial differential of the corrected upper hinge point zero position coordinate using the equation is as follows: the error amount is calculated using the error amount calculation formula; the upper hinge point zero position coordinate in the next iteration is the sum of the error amount in the previous iteration and the corrected upper hinge point zero position coordinate; until the error amount is less than the set threshold value, the iteration process is terminated; the corrected upper hinge point zero position coordinate corresponding to the last iteration is used as the corrected upper hinge point zero position coordinate of each driving rod under the corresponding load state; in the first iteration, the original upper hinge point zero position coordinate is used as the corrected upper hinge point zero position coordinate to calculate the corresponding error amount; The threshold value is the accuracy value that makes the difference between the theoretical length of the driving rod and the corresponding actual length meet the accuracy requirements; The error calculation formula is: Among them, q 1j ,q 2j and q 3j are the errors of the j-th driving rod corresponding to the three groups of attitude angles; f 1j 、f 2j and f 3j are the differences between the square of the theoretical length and the square of the actual length of the j-th driving rod corresponding to the three groups of attitude angles; X aj 、Y aj and Z aj are the X-axis value, Y-axis value, and Z-axis value of the corrected upper hinge zero position coordinates of the j-th driving rod.
4. The method for automatically correcting the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 3 is characterized in that: The equation between the difference between the theoretical length and the corresponding actual length and the corrected zero coordinate of the upper hinge point of the driving member is: Among them, u 1j 、u 2j and u 3j are the X-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, v 1j 、v 2j and v 3j are the Y-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, w 1j 、w 2j and w 3j are the Z-axis values of the lower hinge point of the j-th driving rod in the three groups of attitude angles, L 1j , L 2j and L 3j are the actual lengths of the j-th driving rod corresponding to the three sets of attitude angles.
5. The method for automatically correcting the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 2, characterized in that: The swing platform is controlled to move to three different attitude angles respectively. The angle value of the attitude angle is near zero. Near zero means that the angle value is greater than zero and less than a first set value.
6. An automatic correction device for the zero-position coordinates of the hinge points of a series-parallel structure swing platform, characterized in that: It includes a processor, which is used to control the swing platform to move to three different posture angles under a load state, and obtain the actual length of each driving rod under the three posture angles; calculate the three sets of lower hinge conversion coordinates corresponding to the zero-position coordinates of the lower hinge of each driving rod after the swing platform body rotates through the three posture angles; calculate the theoretical length of each driving rod under the three posture angles, establish an equation between the difference between the theoretical length and the corresponding actual length and the corrected upper hinge zero-position coordinate of the driving rod, solve the equation to determine the corrected upper hinge zero-position coordinate of each driving rod under a load state, so that the difference between the theoretical length of the driving rod and the corresponding actual length meets the accuracy requirements; wherein the theoretical length of the driving rod is determined based on the corrected upper hinge zero-position coordinate and the lower hinge conversion coordinate of the driving rod.
7. The automatic correction device for the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 6 is characterized in that: The processor solves the equation by taking the partial differential of the equation with respect to the corrected zero coordinate of the upper hinge point.
8. The automatic correction device for the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 7 is characterized in that: The process of solving the equation for the partial differential of the corrected upper hinge point zero position coordinate using the equation is as follows: the error amount is calculated using the error amount calculation formula; the upper hinge point zero position coordinate in the next iteration is the sum of the error amount in the previous iteration and the corrected upper hinge point zero position coordinate; until the error amount is less than the set threshold value, the iteration process is terminated; the corrected upper hinge point zero position coordinate corresponding to the last iteration is used as the corrected upper hinge point zero position coordinate of each driving rod under the corresponding load state; in the first iteration, the original upper hinge point zero position coordinate is used as the corrected upper hinge point zero position coordinate to calculate the corresponding error amount; The threshold value is the accuracy value that makes the difference between the theoretical length of the driving rod and the corresponding actual length meet the accuracy requirements; The error calculation formula is: Among them, q 1j ,q 2j and q 3j are the errors of the j-th driving rod corresponding to the three groups of attitude angles; f 1j 、f 2j and f 3j are the differences between the square of the theoretical length and the square of the actual length of the j-th driving rod corresponding to the three groups of attitude angles; X aj 、Y aj and Z aj are the X-axis value, Y-axis value, and Z-axis value of the corrected upper hinge zero position coordinates of the j-th driving rod.
9. The automatic correction device for the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 6, characterized in that: The swing platform is controlled to move to three different attitude angles respectively. The angle value of the attitude angle is near zero. Near zero means that the angle value is greater than zero and less than a first set value.
10. The automatic correction device for the zero-position coordinates of the hinge points of the series-parallel structure swing platform according to claim 6, characterized in that: The processor is a motion controller in a series-parallel structure swing platform control system.