Aerial Imaging Multi-Actuator Interference Allocation Method and Device, Imaging Method and System

Abstract

The present invention discloses an interference allocation method and device for multiple actuators in aerial imaging, an imaging method and a system. The interference allocation method includes: unifying the motion equations of multiple heterogeneous actuators in one coordinate system; establishing the open-loop dynamic models of each actuator; selecting the cut-off frequencies suitable for the dynamic characteristics of each actuator to design corresponding interference observers to compensate for interference; selecting a common cut-off frequency and calculating the interference compensation residuals of each actuator; calculating the motion residuals of each actuator according to the interference compensation residuals of each actuator; and taking the motion residuals of the actuators with low dynamic characteristics as motion commands and allocating them to the actuators with high dynamic characteristics. By performing interference allocation among multiple actuators with different dynamic characteristics and anti-interference capabilities, the present invention improves the collaborative performance of multiple actuators, thereby improving the object-image compensation accuracy of the imaging system. At the same time, it also meets the low-power and high-speed processing requirements of the aerial environment.

Description

Technical Field

[0001] The present invention belongs to the field of automatic control, and particularly relates to a method and device for interference allocation of multiple actuators in aerial imaging, an imaging method, and a system. Background Art

[0002] Aerial imaging equipment is mounted on various moving-base carriers and can flexibly obtain intuitive image information, which is widely used in important fields such as disaster prevention and rescue, geographical mapping, precision agriculture, etc. In a scanning imaging system, due to the image rotation, image shift and other object-image motions generated by the active scanning of the scanning mirror, it is necessary to control various actuators in the imaging equipment to deflect the light beam to improve the imaging quality.

[0003] When multiple actuators are introduced into the imaging system, different actuators are distributed at different positions in the optical path, with different interference mechanisms and magnitudes, different driving principles and motion scales, and different dynamic performances and anti-interference capabilities. The aerial working environment is very complex, and each actuator is subject to external interferences such as the attitude motion of the carrier and wind resistance, and internal interferences such as wire winding, friction, and mass unbalance torque inside the optoelectronic imaging system. Due to the relatively complex actuator model, there are also interferences such as model uncertainty.

[0004] Complex multi-source interferences will affect the control accuracy of the actuators. Existing research mainly focuses on the interference suppression methods for a single actuator. For actuators that compensate for object-image motions such as image shift and image rotation, high-precision coordination among multiple actuators is the primary requirement. Even if the interference suppression accuracy of a certain actuator is higher than that of other actuators, the object-image motion compensation accuracy of the system cannot be further improved. Only by improving the anti-interference performance among multiple actuators as a whole can the object-image motion compensation accuracy of the entire system be improved. Based on this, the technical solution of the present invention is designed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and device for interference allocation of multiple actuators in aerial imaging, an imaging method, and a system, aiming at the deficiencies of the above-mentioned existing technologies. By performing interference allocation among multiple actuators with different dynamic characteristics and anti-interference capabilities, the coordination performance of multiple actuators is improved, and thus the object-image compensation accuracy of the imaging system is improved.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for interference allocation of multiple actuators in aerial imaging, characterized by including the following steps:

[0008] S101, unify the motion equations of multiple heterogeneous actuators in one coordinate system;

[0009] S102, establish the open-loop dynamic model of each actuator;

[0010] S103. Select a cut-off frequency suitable for the dynamic characteristics of each actuator and design a corresponding disturbance observer for each actuator to compensate for disturbances;

[0011] S104. Select a common cut-off frequency and calculate the disturbance compensation residuals of each actuator;

[0012] S105. Calculate the motion residuals of each actuator according to the disturbance compensation residuals of each actuator;

[0013] S106. Use the motion residuals of the actuators with low dynamic characteristics as motion commands and allocate them to the actuators with high dynamic characteristics.

[0014] As a preferred method, the cut-off frequencies corresponding to each actuator selected in step S103 are all less than or equal to the common cut-off frequency selected in step S104.

[0015] Furthermore, step S103 further includes: using a disturbance suppression closed-loop control method to suppress the disturbance compensation residuals of each actuator.

[0016] As a preferred method, the cut-off frequencies corresponding to each actuator selected in step S103 satisfy the condition: the cut-off frequency corresponding to the actuator with poor dynamic characteristics is lower than the cut-off frequency corresponding to the actuator with good dynamic characteristics.

[0017] Based on the same inventive concept, the present invention also provides an aviation imaging multi-actuator interference distribution device, which is modularly arranged to meet the low-power and high-speed processing requirements of the aviation environment. It is characterized by including a lumped information processing module and multiple single-actuator processing modules; each single-actuator processing module corresponds to a different heterogeneous actuator; each single-actuator processing module includes a control unit, a communication unit, an output unit, and an input unit; wherein:

[0018] The input unit is used to input the position and / or speed signals of the corresponding actuator obtained into the control unit;

[0019] The control unit is used to: unify the motion equations of multiple heterogeneous actuators in one coordinate system; establish an open-loop dynamic model of each actuator; select a cut-off frequency suitable for the dynamic characteristics of each actuator and design a corresponding disturbance observer for each actuator to compensate for disturbances; select a common cut-off frequency and calculate the disturbance compensation residuals of each actuator; calculate the motion residuals of each actuator according to the disturbance compensation residuals of each actuator and send them to the lumped information processing module through the communication unit;

[0020] The communication unit is used to realize the two-way information transmission between each single-actuator processing module and the lumped information processing module;

[0021] The lumped information processing module is used to distribute the motion residual of the actuator with low dynamic characteristics as a motion command to the control unit corresponding to the actuator with high dynamic characteristics through the communication unit;

[0022] The output unit is used to send a control amount to the corresponding driver according to the motion command received by the control unit.

[0023] As a preferred method, the cut-off frequencies corresponding to the selected actuators by the control unit are all less than or equal to the selected general cut-off frequency.

[0024] Furthermore, the control unit is also used to suppress the interference compensation residual of each actuator by using the interference suppression closed-loop control method.

[0025] As a preferred method, the cut-off frequencies corresponding to the selected actuators by the control unit satisfy the condition that the cut-off frequency corresponding to the actuator with poor dynamic characteristics is lower than the cut-off frequency corresponding to the actuator with good dynamic characteristics.

[0026] Based on the same inventive concept, the present invention also provides an aerial imaging method, which is characterized by including: performing interference distribution on multiple actuators according to the aerial imaging multi-actuator interference distribution method described above.

[0027] Based on the same inventive concept, the present invention also provides an aerial imaging system, which is characterized by including the aerial imaging multi-actuator interference distribution device described above.

[0028] Compared with the prior art, the present invention improves the collaborative performance of multiple actuators by performing interference distribution among multiple actuators with different dynamic characteristics and anti-interference capabilities, thereby improving the object-image compensation accuracy of the imaging system, and at the same time meeting the low-power and high-speed processing requirements of the aerial environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flowchart of an embodiment of the aerial imaging multi-actuator interference distribution method described in the present invention.

[0030] Figure 2 It is a control structure diagram of the actuator for the aerial imaging multi-actuator interference distribution method described in the present invention.

[0031] Figure 3 It is a schematic diagram of the hardware structure of the aerial imaging multi-actuator interference distribution device described in the present invention.

[0032] Figure 4 It is a schematic diagram of the information interaction between different single-actuator processing modules in the aerial imaging multi-actuator interference distribution device described in the present invention.

[0033] Among them, Z1 to Zn are actuators, Q1 to Qn are drivers, J is a lumped information processing module, D1 to Dn are single-actuator processing modules, D101 to Dn01 are control units, D102 to Dn02 are communication units, D103 to Dn03 are output units, and D104 to Dn04 are input units. Detailed implementation mode

[0034] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0035] The terms "first", "second", "third", "fourth", etc. in the specification, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0036] Let there be n actuators in the aerial imaging equipment, including p rotary actuators with a rotation angle of θ i , i = 1, 2,.., p, and n-p translational actuators with a movement displacement of l i , i = p + 1, p + 2,..., n, and the movement scales between the same type of rotary actuators or translational actuators are not necessarily exactly the same.

[0037] As Figure 1 shown, the present invention provides a method for distributing interference of multiple actuators in aerial imaging, and the method includes the following steps:

[0038] In the first aspect, the present invention provides a method for distributing interference of multiple actuators in aerial imaging. The method includes:

[0039] Let there be n actuators Z1 to Zn in the aerial imaging equipment, including p rotary actuators with a rotation angle of θ i , i = 1, 2,.., p, and n-p translational actuators with a movement displacement of li , translational actuators for i = p + 1, p + 2,..., n, and the motion scales between the same type of rotational actuators or translational actuators are not necessarily exactly the same.

[0040] S101. First, unify the motion equations of heterogeneous actuators Z1 to Zn with different motion scales and different motion dimensions on a coordinate system, and let the transformation equation be:

[0041]

[0042] where x i is the position state of actuators Z1 to Zn after unification, are the scale transformation matrix and the shape transformation matrix respectively, and their specific forms are related to the positions and functions of actuators Z1 to Zn in the optical path of the imaging system.

[0043] S102. For the design of the disturbance suppression and compensation loop for any actuators Z1 to Zn, first establish the open-loop dynamic model of actuator Zi as

[0044]

[0045] where J i is the nominal inertia of the system; B i is the nominal damping of the system. Identify the parameters of actuators Z1 to Zn through system identification methods.

[0046] S103. Select the cut-off frequency g i that suits the dynamic characteristics of actuators Z1 to Zn and design the low-pass filter Q i (s). For aviation imaging actuators with poor dynamic characteristics, such as the mechanical frame and scanning mirror driven by torque motors with relatively large inertia in scanning imaging equipment, the cut-off frequency can be selected as dozens of Hertz. For aviation imaging actuators with good dynamic characteristics, such as fast steering mirrors or stabilization devices driven by voice coil motors or piezoelectric ceramic drivers, with small inertia, large stiffness, and good dynamic performance, the cut-off frequency can be selected as several hundred Hertz.

[0047] Use a disturbance observer to estimate the disturbance suffered by actuator Zi and feed the estimated value back to actuator Zi for disturbance compensation. The expression form of the low-pass filter is:

[0048]

[0049] where are coefficients, N is the order of the denominator, M is the order of the numerator, and N - M is the relative order. is the time constant.

[0050] Design appropriate closed-loop control methods for interference suppression, such as sliding mode control, H-infinity control, adaptive robust control, etc., to further suppress the interference compensation residuals of the actuator Zi.

[0051] S104. Select a new common cut-off frequency g that is greater than or equal to the cut-off frequencies of all actuators Z1 to Zn. ALL , Design a common low-pass filter Q ALL (s). Design an additional interference observer to perform broadband interference estimation on the interference compensation and suppression residuals of all actuators Z1 to Zn. Let the real-time interference compensation residual of the actuator Zi be dres i .

[0052] S105. For the actuator j with a lower dynamic frequency, based on its interference compensation residual dres j and the dynamic model, estimate the motion residual xres caused by the interference compensation residual j .

[0053] S106. Use the motion residual of the actuator with a lower dynamic frequency as an additional motion command and assign it to the actuator with a higher dynamic frequency to improve the cooperative motion accuracy between actuators with different dynamic characteristics.

[0054] As Figure 2 shown, taking the high-dynamic actuator 1, high-dynamic actuator 2, and low-dynamic actuator 3 as examples, the interference allocation process of the present invention is shown. Using the method of the present invention to obtain the motion residuals xres 1 ~xres 3 corresponding to the 3 actuators, and then through the cooperative controller, use the motion residual of the low-dynamic actuator 3 as an additional motion command and assign it to the high-dynamic actuators 1 and 2 to improve the cooperative motion accuracy between the 3 actuators with different dynamic characteristics.

[0055] As Figure 3 and Figure 4 shown, the present invention also provides an aerial imaging multi-actuator interference allocation device, which is modularly arranged to meet the low-power and high-speed processing requirements of the aerial environment.

[0056] The aerial imaging multi-actuator interference allocation device includes an aggregated information processing module J and multiple single-actuator processing modules D1 to Dn; each single-actuator processing module Di corresponds to a different actuator Zi one by one; each single-actuator processing module Di includes a control unit Di01, a communication unit Di02, an output unit Di03, and an input unit Di04; where:

[0057] The input units D104 to Dn04 are used to input the position and / or speed signals of the corresponding actuators Z1 to Zn obtained to the control units D101 to Dn01;

[0058] The control units D101 to Dn01 are used to: unify the motion equations of multiple heterogeneous actuators Z1 to Zn in one coordinate system; establish the open-loop dynamic models of the actuators Z1 to Zn; select cut-off frequencies suitable for the dynamic characteristics of the actuators Z1 to Zn to design corresponding disturbance observers for compensating disturbances for the actuators Z1 to Zn; select a common cut-off frequency and calculate the disturbance compensation residuals of the actuators Z1 to Zn; calculate the motion residuals of the actuators Z1 to Zn according to the disturbance compensation residuals of the actuators Z1 to Zn and send them to the lumped information processing module J through the communication units D102 to Dn02;

[0059] The communication units D102 to Dn02 are used to realize the two-way information transmission between each single actuator processing module D1 to Dn and the lumped information processing module J;

[0060] The lumped information processing module J is used to distribute the motion residuals of the actuators Z1 to Zn with low dynamic characteristics as motion commands to the corresponding control units D101 to Dn01 of the actuators Z1 to Zn with high dynamic characteristics through the communication units D102 to Dn02;

[0061] The output units D103 to Dn03 are used to send control quantities to the corresponding drivers Q1 to Qn according to the motion commands received by the control units D101 to Dn01.

[0062] Specifically:

[0063] The control units D101 to Dn01 use the STM32F407IGH6 based on the ARM core as the embedded processor to core to perform disturbance compensation and control for each actuator Z1 to Zn. This chip is a 32-bit high-performance ARM Cortex-M4 processor with a clock frequency up to 168 MHz, supporting floating-point operations, and can realize the processing of high-speed data.

[0064] The output units D103 to Dn03 adopt the hardware design with the DAC8822 chip as the core. This chip can output the control quantities of the actuators Z1 to Zn calculated in real time to the corresponding drivers Q1 to Qn of the actuators Z1 to Zn.

[0065] The input units D104 to Dn04 adopt the hardware design with the low-noise and low-power AD7656 chip as the core, which can realize high-speed sampling of up to 250 kSPS per channel and only consumes 160 Mw. This chip is directly connected to the position / velocity sensors of the actuators Z1 to Zn and can read the feedback data of the sensors in real time.

[0066] The communication units D102 to Dn02 complete high-speed differential bidirectional information transmission based on the MAX3490 chip with a maximum supported baud rate of 10 Mbps and using the RS-422 transmission protocol.

[0067] The lumped information processing module J performs high-speed processing of highly parallel data based on the FPGA chip of the XC4VFX60-FF1152 model from XILINX. There is 4 Mbit RAM, 56,880 logic gates, and 128 XtremeDSP modules inside this chip, which is sufficient for a large amount of high-speed data processing. In particular, the on-chip 18K RAM module operates at 500 MHz and supports true dual-port read-write synchronous operations, providing resources for high-speed data interaction between chips.

[0068] The lumped information processing module J conducts two-way communication with the communication unit Di02 of each single actuator processing module Di. The communication unit Di02 of the single actuator processing module Di sends the actuator Zi motion residual calculated according to the general cut-off frequency to the lumped information processing module J for further distribution of interference.

[0069] The control units D101 to Dn01 first transform different actuators Z1 to Zn to the same coordinate system according to the following transformation equations:

[0070]

[0071] where x i is the position state of the unified actuator Zi, are the scale transformation matrix and the shape transformation matrix respectively, and their specific forms are related to the position and function of the actuator Zi in the optical path of the imaging system.

[0072] Then, establish the open-loop dynamics model of the actuator Zi as

[0073]

[0074] where J i is the nominal inertia of the system; B i is the nominal damping of the system. Identify the parameters of the actuator Zi through system identification methods.

[0075] Next, select the cut-off frequency g suitable for the dynamic characteristics of the actuator Zi i Design a low-pass filter Q i (s). Design a discrete disturbance observer in the program to estimate the disturbance received by the actuator Zi and feed the estimated value back to the actuator Zi for disturbance compensation. The expression form of the low-pass filter is:

[0076]

[0077] wherein is a coefficient, N is the order of the denominator, M is the order of the numerator, and N - M is the relative order. is the time constant.

[0078] Design appropriate closed-loop control methods for interference suppression, such as sliding mode control, H-infinity control, adaptive robust control, etc., to further suppress the interference compensation residuals of the actuators.

[0079] Select a new common cut-off frequency g that is greater than or equal to the cut-off frequencies of all actuators Z1 to Zn. ALL , design a common low-pass filter Q ALL (s), design an additional interference observer to perform wide-band interference estimation on the interference compensation and suppression residuals of all actuators Z1 to Zn. According to its interference compensation residual dres j and the dynamic model, estimate the motion residual xres caused by the interference compensation residual j .

[0080] The communication unit Di02 of the actuator Zi sends the calculated motion residual xres j to the lumped information processing module J. The lumped information processing module J distributes the motion residuals of the low-dynamic actuators to the high-dynamic actuators according to the budgeted dynamic characteristics of the actuators, so as to achieve high-precision coordination among different dynamic actuators Z1 to Zn.

[0081] The present invention also provides an aerial imaging method, which performs interference allocation on multiple actuators according to the aerial imaging multi-actuator interference allocation method described above.

[0082] The present invention also provides an aerial imaging system, which includes the aerial imaging multi-actuator interference allocation device described above.

[0083] Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed on relevant hardware through program-generated instructions. The program can be stored in a computer-readable storage medium, and the storage medium can include: read-only memory, random access memory, hard disk, etc.

[0084] The above has introduced in detail the aerial imaging multi-actuator interference allocation method and device, imaging method and system of the present invention. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Those of ordinary skill in the art, under the inspiration of the present invention, without departing from the spirit and scope protected by the claims of the present invention, can also make many forms, and these all fall within the protection scope of the present invention.

Claims

1. An interference allocation method for multi-actuators in aerial imaging, characterized in that, it includes the following steps: S101, unify the motion equations of multiple heterogeneous actuators on one coordinate system; S102, establish the open-loop dynamic models of each actuator; S103, select the cut-off frequencies suitable for the dynamic characteristics of each actuator to design corresponding disturbance observers to compensate for disturbances; S104, select a common cut-off frequency and calculate the disturbance compensation residuals of each actuator; S105, calculate the motion residuals of each actuator according to the disturbance compensation residuals of each actuator; S106, take the motion residuals of the actuators with low dynamic characteristics as motion commands and allocate them to the actuators with high dynamic characteristics.

2. The interference allocation method for multi-actuators in aerial imaging according to claim 1, characterized in that, the cut-off frequencies corresponding to each actuator selected in step S103 are all less than or equal to the common cut-off frequency selected in step S104.

3. The interference allocation method for multi-actuators in aerial imaging according to claim 1, characterized in that, step S103 further includes: using the disturbance suppression closed-loop control method to suppress the disturbance compensation residuals of each actuator.

4. The interference allocation method for multi-actuators in aerial imaging according to any one of claims 1 to 3, characterized in that, the cut-off frequencies corresponding to each actuator selected in step S103 satisfy the condition: the cut-off frequency corresponding to the actuator with poor dynamic characteristics is lower than the cut-off frequency corresponding to the actuator with good dynamic characteristics.

5. An interference allocation device for multi-actuators in aerial imaging, characterized in that, it includes a lumped information processing module and multiple single-actuator processing modules; each single-actuator processing module corresponds to a heterogeneous actuator one by one; each single-actuator processing module includes a control unit, a communication unit, an output unit, and an input unit; where: The input unit is used to input the position and / or speed signals of the corresponding actuator obtained into the control unit; The control unit is used to: unify the motion equations of multiple heterogeneous actuators on one coordinate system; establish the open-loop dynamic models of each actuator; select the cut-off frequencies suitable for the dynamic characteristics of each actuator to design corresponding disturbance observers to compensate for disturbances; select a common cut-off frequency and calculate the disturbance compensation residuals of each actuator; calculate the motion residuals of each actuator according to the disturbance compensation residuals of each actuator and send them to the lumped information processing module through the communication unit; The communication unit is used to realize the two-way information transmission between each single-actuator processing module and the lumped information processing module; The lumped information processing module is used to take the motion residuals of the actuators with low dynamic characteristics as motion commands and allocate them to the control unit corresponding to the actuators with high dynamic characteristics through the communication unit; The output unit is used to send the control quantity to the corresponding driver according to the motion command received by the control unit.

6. The interference allocation device for multi-actuators in aerial imaging according to claim 5, characterized in that, the cut-off frequencies corresponding to each actuator selected by the control unit are all less than or equal to the selected common cut-off frequency.

7. The interference allocation device for multi-actuators in aerial imaging according to claim 5, characterized in that, The control unit is further configured to suppress the interference compensation residuals of each actuator by using an interference suppression closed-loop control method.

8. The aerial imaging multi-actuator interference allocation device according to any one of claims 5 to 7, wherein, the cut-off frequencies corresponding to the actuators selected by the control unit satisfy the condition that the cut-off frequency corresponding to the actuator with relatively poor dynamic characteristics is lower than the cut-off frequency corresponding to the actuator with relatively good dynamic characteristics.

9. An aerial imaging method, wherein, it includes: performing interference allocation on multiple actuators according to the aerial imaging multi-actuator interference allocation method according to any one of claims 1 to 4.

10. An aerial imaging system, wherein, it includes the aerial imaging multi-actuator interference allocation device according to any one of claims 5 to 8.

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