Kinetic parameter identification method and device, electronic equipment and readable storage medium
By transforming the dynamic equations of the parallel mechanism into a series form and performing kinematic equivalence, the identification process of dynamic parameters is simplified, the problem of complex modeling of traditional parallel mechanisms is solved, and control efficiency and accuracy are improved.
Patent Information
- Application Number
- CN202511072243.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-31
- Publication Date
- 2025-10-28
AI Technical Summary
The dynamic modeling of traditional parallel mechanisms is complex and requires solving complex high-dimensional nonlinear dynamic equations, which affects the control efficiency of the robot.
The initial dynamic equations of the parallel mechanism are transformed into series dynamic equations by using equivalent dynamic parameters, and the equivalent control torque is transformed into the actuator space based on kinematic equivalence, simplifying the dynamic parameter identification process.
This avoids the complexity of directly solving high-dimensional nonlinear dynamic equations and improves the dynamic control efficiency and identification accuracy of parallel mechanisms.
Smart Images
Figure CN120839786A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of robot control technology, and more specifically to a method, apparatus, electronic device, and readable storage medium for identifying dynamic parameters. Background Technology
[0002] In related technologies, robots typically include two basic structural topologies. Parallel mechanisms refer to closed-loop systems consisting of a moving platform (End-Effector) connected to a stationary platform (Base) via at least two independent kinematic chains. The motion of the moving platform is achieved through the coordinated action of all driven joints. Serial mechanisms, on the other hand, consist of a series of links and driven joints positioned between them, connected sequentially via kinematic chains along a single path. The motion of the end effector is the cumulative superposition of the motions of each joint.
[0003] However, traditional parallel mechanism dynamics modeling is complex, often requiring consideration of closed-loop chain coupling and multi-degree-of-freedom interaction. This often necessitates solving complex high-dimensional nonlinear dynamic equations to identify the dynamic parameters of the parallel mechanism, thereby affecting the robot's control efficiency. Summary of the Invention
[0004] The embodiments of this application provide a method, apparatus, electronic device, and readable storage medium for identifying dynamic parameters, which can simplify the identification of dynamic parameters of parallel mechanisms and at least partially solve the above-mentioned technical problems.
[0005] In a first aspect, embodiments of this application provide a method for identifying dynamic parameters, including:
[0006] Based on the equivalence of dynamic parameters, the initial dynamic equations of the target parallel mechanism in parallel form are transformed into target dynamic equations in series form;
[0007] Based on the target dynamic equation, the dynamic parameters of the target parallel mechanism are identified to obtain the equivalent control torque of the target structure in the target parallel mechanism;
[0008] Based on kinematic equivalence, the equivalent control torque is converted into the control space of the target actuator of the target parallel mechanism to obtain the target control torque.
[0009] In one embodiment, the method further includes:
[0010] Obtain the dynamic behavior characteristics of the target parallel mechanism;
[0011] When the dynamic behavior characteristics meet the preset conditions, the step of converting the dynamic equations of the target parallel mechanism into the target dynamic equations in series form based on dynamic equivalence is performed.
[0012] In one embodiment, the dynamic behavior characteristics include structural mass distribution, structural motion mode, and coupling strength between structures;
[0013] The dynamic behavior characteristics satisfy at least one of the following preset conditions:
[0014] The similarity between the first structural mass distribution of the target parallel mechanism and the second structural mass distribution of the series mechanism exceeds a preset similarity threshold.
[0015] The ratio of the number of target structures moving in the first motion mode in the target parallel mechanism to the total number of structures in the target parallel mechanism exceeds a preset ratio threshold.
[0016] The coupling strength between the structures in the target parallel mechanism does not exceed a preset coupling threshold.
[0017] In one embodiment, the process of converting the initial dynamic equations of the target parallel mechanism in parallel form into target dynamic equations in series form based on equivalent dynamic parameters includes:
[0018] Based on the Jacobian matrix, each dynamic parameter in the initial dynamic equation is transformed into an equivalent dynamic parameter in series form;
[0019] Based on the equivalent dynamic parameters and the dynamic equation form of the series mechanism, the target dynamic equation of the target parallel mechanism in the series form is determined.
[0020] In one embodiment, the step of transforming each dynamic parameter in the initial dynamic equation into an equivalent dynamic parameter in series form based on the Jacobian matrix includes:
[0021] Based on the Jacobian matrix, each dynamic parameter of the end-operating space of the target parallel mechanism in the initial dynamic equation is projected to the joint space of the target parallel mechanism to obtain the equivalent dynamic parameter of each dynamic parameter in the joint space.
[0022] In one embodiment, the step of converting the equivalent control torque based on kinematic equivalence into the control space of the target actuator of the target parallel mechanism to obtain the target control torque includes:
[0023] A mapping matrix is determined based on the equivalent correlation between the kinematic parameters of the target structure and the kinematic parameters of the target actuator; the kinematic parameters include pose parameters and / or motion parameters.
[0024] The equivalent control torque is processed based on the mapping matrix to transform the equivalent control torque into the control space of the target actuator of the target parallel mechanism, thereby obtaining the target control torque.
[0025] In one embodiment, the method further includes:
[0026] The target parallel mechanism is dynamically controlled based on the target control torque, and the dynamic control includes at least one of inverse dynamic control, impedance control, and force-position hybrid control.
[0027] Secondly, embodiments of this application provide a dynamic parameter identification device, comprising:
[0028] The dynamic equivalence module is used to transform the initial dynamic equations of the target parallel mechanism in parallel form into the target dynamic equations in series form based on the equivalence of dynamic parameters;
[0029] The identification module is used to identify the dynamic parameters of the target parallel mechanism based on the target dynamic equation, and to obtain the equivalent control torque of the target structure in the target parallel mechanism;
[0030] The kinematic equivalence module is used to convert the equivalent control torque into the control space of the target actuator of the target parallel mechanism based on kinematic equivalence, so as to obtain the target control torque.
[0031] Thirdly, embodiments of this application provide an electronic device, the electronic device comprising:
[0032] one or more processors;
[0033] Memory; and
[0034] One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement the method for identifying the dynamic parameters described in any of the preceding claims.
[0035] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to execute the dynamic parameter identification method described in any of the preceding claims.
[0036] In the embodiments of this application, the dynamic equations of the parallel mechanism are converted into equivalent series form through a dynamic equivalence method, so as to allow the identification of the equivalent dynamic parameters of the system through the dynamic identification method of the series mechanism. Then, based on the kinematic equivalence method, the equivalent dynamic parameters are restored to the end execution space of the parallel mechanism. This can avoid the process of directly solving the complex high-dimensional nonlinear dynamic equations of the parallel mechanism, simplify the identification difficulty of the dynamic parameters of the parallel mechanism, and thus improve the dynamic control efficiency of the parallel mechanism. Attached Figure Description
[0037] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0038] Figure 1a This is a schematic diagram of a parallel mechanism;
[0039] Figure 1b This is a schematic diagram of another type of parallel mechanism;
[0040] Figure 2 A schematic flowchart illustrating the steps of a method for identifying dynamic parameters provided in an embodiment of this application;
[0041] Figure 3 This application provides a schematic flowchart of the steps for performing dynamic parameter equivalence on dynamic equations based on dynamic behavior characteristics.
[0042] Figure 4 This application provides a schematic flowchart of a kinetic equivalent transformation process.
[0043] Figure 5 This application provides a schematic flowchart illustrating the steps for kinematically equivalent mapping of control torque in an embodiment of the present application.
[0044] Figure 6 A schematic diagram of the structure of a dynamic parameter identification device provided in an embodiment of this application;
[0045] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation
[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.
[0047] To facilitate understanding of the dynamic parameter identification method, apparatus, electronic device, and readable storage medium provided in this application, the application scenarios of the dynamic parameter identification method provided in this application are first described below. Specifically, the dynamic parameter identification method provided in this application is mainly used to identify the dynamic parameters of a robot in order to achieve dynamic control of the robot. In related technologies, compared with serial mechanisms, robots with parallel mechanisms, such as the traditional Stewart platform (a six-degree-of-freedom parallel mechanism model consisting of upper and lower platforms connected by six retractable struts via ball joints or Hooke joints, characterized by high stiffness, strong load-bearing capacity, and fast dynamic response), Delta parallel mechanisms (a closed-loop mechanism with three degrees of freedom driven in parallel), or biomimetic robots (robots that simulate the walking of specific organisms and thus have a biomimetic four-wheel drive system, such as legged robots), often have complex dynamic equations due to closed-loop chain coupling and multi-degree-of-freedom interaction. When fitting dynamic parameters through experimental data, it is often necessary to solve complex high-dimensional nonlinear dynamic equations, resulting in less than ideal parameter identification. For details, please refer to [link to relevant documentation]. Figures 1a-1b The diagram below shows the model structure of several parallel mechanisms provided in the embodiments of this application. Details are as follows.
[0048] like Figure 1a The diagram shows a schematic of a Stewart platform model structure. The upper plane includes six joint connection nodes, p1 to p6, and the lower plane also includes six joint connection nodes, b1 to b6. The corresponding nodes are connected by support rods. By adjusting the parameters of each joint node, the six degrees of freedom of the upper and lower planes can be adjusted.
[0049] like Figure 1bThe diagram shows a schematic of a Delta parallel mechanism, which includes a static platform r and a moving platform R, as well as three identical motion chains J1, J2 and J3. Each chain contains two rigid links and three types of joints, forming a closed-loop parallelogram. The proximal arm L1 connects the static platform and the parallelogram closed-loop unit L2. The parallelogram closed-loop unit L2 connects to the moving platform to constrain the motion of the moving platform, thereby converting the rotation of the proximal arm into a pure translation of the moving platform.
[0050] To address the aforementioned technical problems, this application provides a method that uses dynamic equivalence to transform complex high-dimensional nonlinear dynamic equations into dynamic equations in a series form. Based on these series-form dynamic equations, dynamic parameters are identified. Furthermore, based on kinematic equivalence, the identified dynamic parameters are projected into the end effector space of the parallel mechanism, thereby achieving control of the end effector. Specifically, for ease of understanding, the following description will be provided in conjunction with specific embodiments.
[0051] Please see Figure 2 , Figure 2 This application provides a flowchart illustrating the steps of a method for identifying dynamic parameters, specifically including steps S210 to S230:
[0052] S210, based on the equivalence of dynamic parameters, transforms the initial dynamic equations of the target parallel mechanism in parallel form into the target dynamic equations in series form.
[0053] In one embodiment of this application, the dynamic modeling of parallel mechanisms is more complex than that of serial mechanisms, mainly due to the constraint forces / torques introduced by their closed-loop structure. The initial dynamic equations typically refer to the original differential-algebraic equations describing the relationship between the mechanism's motion and the driving / constraint forces in the joint space or operating space. For example, as a possible implementation, it can be obtained based on the Newton-Euler method combined with the principle of virtual work or the Lagrange multiplier method. Specifically, taking the dynamic equations of the operating space, i.e., the moving platform, as an example, the expression of its initial dynamic equations is as follows:
[0054]
[0055] Among them, M p Let be the generalized mass matrix (6x6) of the moving platform, which is usually symmetric positive definite and is typically related to the pose of the moving platform.
[0056] The generalized acceleration vector of the moving platform (6x1, including linear acceleration and angular acceleration).
[0057] C p : Generalized Coriolis force and centripetal force vector of the moving platform (6x1).
[0058] G p : The gravity vector of the moving platform (6x1).
[0059] J p The overall motion Jacobian matrix of the mechanism can be used to calculate the speed of the moving platform. Mapped to active joint velocity q a ,Right now
[0060] f a The force / torque vector applied to the end of the branch by the active joint (at the connection point of the moving platform) is typically equal to the driving force of the active joint (such as motor torque) mapped to the end effector space. Its dimension is equal to the number of active joints, n. a .
[0061] External forces / torques acting on the moving platform (6x1).
[0062] Of course, in addition to the dynamic equations of the operating space provided above, the dynamic equations of parallel mechanisms usually also include the dynamic equations of each branch chain in the joint space, which are usually related to the dynamic parameters of each branch chain, such as the Coriolis force, centripetal force vector, gravity vector, etc. mentioned above. In addition, the driving force parameter τ of the branch chain may also be included. a .
[0063] In related technologies, in order to solve the above-mentioned initial dynamic equations, it is often necessary to construct closed-loop constraint equations at the connection points between the moving platform and the branch, the connection points between the branch and the stationary platform, and the joints inside the branch to realize the closed-loop structure. For example, by using position, velocity, acceleration and other parameter constraints, passive joint variables and constraint forces are eliminated, and equations are obtained only concerning active joint variables (or operating space variables) and driving forces.
[0064] To address the aforementioned problems, this application considers transforming the parallel-form initial dynamic equations into a series-form target dynamic equations using the concept of equivalent dynamic parameters. Specifically, the target dynamic equations can take the following form:
[0065] M(q a )*q a +C(q a q a )*q a +G(q a )=τ a
[0066] Where M(q) a ), C(q) a qa ), G(q a This can be understood as equivalent to the target structure, such as the mass matrix, centrifugal force / Coriolis force vector, and gravity vector of the active joint space, which includes the equivalent effects of all passive joints and the inertia and constraints of the moving platform.
[0067] Of course, it should be noted that due to the morphological differences between parallel and series mechanisms, when transforming the initial dynamic equations of a parallel mechanism into the target dynamic equations of a series mechanism based on equivalent dynamic parameters, the loss of coupling relationships between structures may lead to differences in the transformed dynamic models, thus affecting the accuracy of subsequent identification of dynamic parameters. Therefore, in some embodiments of this application, based on the analysis of parallel and series mechanisms, some dynamic behavior characteristics of the parallel mechanism are identified. Only when it is determined that the dynamic behavior of the parallel mechanism is approximately the same as that of the series mechanism is the dynamic parameter identification method provided in this application executed. This avoids significant differences in the identification results of the dynamic parameters of the parallel mechanism due to large errors in the dynamic model, which could affect the subsequent control effect. For details, please refer to... Figure 3 , Figure 3 This application provides a flowchart illustrating the steps for performing dynamic parameter equivalence on dynamic equations based on dynamic behavior characteristics, specifically including steps S310 to S320:
[0068] S310, Obtain the dynamic behavior characteristics of the target parallel mechanism.
[0069] In this embodiment, the dynamic behavior characteristics of the target parallel mechanism refer to characteristic information that can be used to describe the dynamic behavior of the parallel mechanism, which is usually associated with the shape of the target parallel mechanism. Specifically, in some embodiments, these behavioral characteristics can usually be used to describe the inertia matrix and coupling terms in the dynamic model, thereby determining the strength of the lost coupling relationship between structures after the dynamic equations of the target parallel mechanism are transformed into an equivalent series form. Specifically, in one embodiment, the dynamic behavior characteristics can usually include structural mass distribution, structural motion mode, and coupling strength between structures, etc. For example, structural mass distribution can include whether it is concentrated in a specific structure, such as a robotic arm similar to a series mechanism, where the mass is concentrated in a specific structure, such as the end effector, or whether it is uniformly distributed. The structural motion mode can usually include the operating mode of each branch, which is usually determined by the connecting joints of the branches. When the joints mainly move in a rotational manner, the inertia influence of the branches is often relatively low.
[0070] S320, when the dynamic behavior characteristics meet the preset conditions, the dynamic equation of the target parallel mechanism is transformed into the target dynamic equation in series form based on dynamic equivalence.
[0071] In this embodiment, when the dynamic behavior characteristics of the target parallel mechanism meet preset conditions—that is, when the dynamic behavior of the target parallel mechanism is considered similar to that of a series mechanism—the dynamic equations of the target parallel mechanism can be transformed into target dynamic equations in series form based on dynamic equivalence, and the resulting equivalent series form model has a smaller error. Specifically, taking the aforementioned structural mass distribution, structural motion mode, and coupling strength between structures as examples, the preset conditions for the dynamic behavior characteristics may include at least one of the following:
[0072] The similarity between the first structural mass distribution of the target parallel mechanism and the second structural mass distribution of the series mechanism exceeds a preset similarity threshold.
[0073] The ratio of the number of target structures moving in the first motion mode in the target parallel mechanism to the total number of structures in the target parallel mechanism exceeds a preset ratio threshold.
[0074] The coupling strength between the structures in the target parallel mechanism does not exceed a preset coupling threshold.
[0075] The similarity between the mass distribution of the first structure of the target parallel mechanism and the mass distribution of the second structure of the series mechanism refers to whether the target parallel mechanism and the series mechanism have similar structural mass distributions. For example, whether the mass distribution is concentrated in a specific structure, such as the end effector. This can usually be determined by calculating the vector similarity after normalizing the mass vectors of each structure in the parallel mechanism and the mass vectors of each structure in the series mechanism. Specifically, if the similarity between the mass distribution of the first structure of the target parallel mechanism and the mass distribution of the second structure of the series mechanism exceeds a preset threshold, it indicates that the target parallel mechanism and the series mechanism have highly similar mass distributions. Since the mass distribution determines the inertia matrix and coupling terms in the dynamic model, for example, if the mass is concentrated in the end effector (similar to a series robotic arm), the inertial coupling between branches can be ignored. In this case, the equivalent series model transformed based on the equivalent dynamic parameters has a small error. In particular, since biomimetic robots, such as legged robots, are typically designed to meet the condition that the main branches can be clearly distinguished and the mass distribution is concentrated in each main rigid body, in some embodiments of this application, biomimetic robots can be approximated as serial systems for identifying dynamic parameters, thereby significantly reducing the complexity of dynamic modeling of biomimetic systems such as the limbs of legged robots.
[0076] Furthermore, the ratio of the number of target structures moving in the first motion mode to the total number of structures in the target parallel mechanism exceeds a preset ratio threshold. This means that the main motion mode of each joint in the target parallel mechanism is determined, such as rotation or translation. Specifically, when the joints of each branch are mainly rotated, that is, when the ratio of the number of target structures moving in the first motion mode to the total number of structures in the target parallel mechanism exceeds the preset ratio threshold, it can be considered that the influence of branch inertia in the target parallel mechanism is small, and the coupling relationship between branches is weak. Therefore, in the process of converting the target dynamic equations into a series form based on the dynamic parameters, the error of the equivalent series model is relatively low, which can ensure the accuracy of dynamic parameter identification to a certain extent.
[0077] Finally, ensuring that the coupling strength between structures in the target parallel mechanism does not exceed a preset coupling threshold can be determined by analyzing the connection relationships between the target parallel mechanisms, thereby determining the coupling strength between each structure. If the target parallel mechanism is a strongly coupled parallel mechanism, i.e., the coupling strength exceeds the preset coupling threshold, then the inertia of each branch cannot be ignored. In this case, if the dynamic parameter identification method provided in this application is used, it often leads to a large model error, which to some extent affects the accuracy of the dynamic parameter identification. Therefore, the dynamic parameter identification method in related technologies can often be used, i.e., fitting dynamic parameters (such as inertia and friction coefficient) through experimental data to solve the initial dynamic equations in the parallel form. Of course, it should be noted that in some scenarios where precise control is not required, but only a fast response is needed, the dynamic parameter identification method provided in this application can still be used.
[0078] Specifically, to clearly understand the equivalent transformation process of the dynamic parameters provided in the embodiments of this application for the parallel dynamic equations, the following will be described in conjunction with specific embodiments. For details, please refer to... Figure 4 , Figure 4 This application provides a schematic flowchart of a kinetic equivalent transformation process, specifically including steps S410 to S420:
[0079] S410, based on the Jacobian matrix, transform each dynamic parameter in the initial dynamic equation into an equivalent dynamic parameter in series form.
[0080] In this embodiment, processing each dynamic parameter in the initial dynamic equation based on the Jacobian matrix can be considered as obtaining its equivalent dynamic parameters in series form. For example, these typically include equivalent inertia, and may also include equivalent velocity parameters, equivalent gravity parameters, or equivalent friction parameters, etc. Taking the dynamic equation in the operating space as an example, the dynamic equation in the operating space includes a mass matrix, acceleration vector, generalized Coriolis force and centripetal force vector, gravity vector, etc. These can be projected onto the joint space using the Jacobian matrix to obtain the equivalent parameters in the joint space, such as M(q). a ), C(q) a q a ), G(q a ), etc. That is, in one embodiment, the transformation of each dynamic parameter in the initial dynamic equation into an equivalent dynamic parameter in series form based on the Jacobian matrix includes:
[0081] Based on the Jacobian matrix, each dynamic parameter of the end-operating space of the target parallel mechanism in the initial dynamic equation is projected to the joint space of the target parallel mechanism to obtain the equivalent dynamic parameter of each dynamic parameter in the joint space.
[0082] S420, Based on the equivalent dynamic parameters and the dynamic equation form of the series mechanism, determine the target dynamic equation of the target parallel mechanism in the series form.
[0083] Based on the equivalent dynamic parameters obtained above, such as G(q) a ), C(q) a q a ), G(q a By combining the dynamic equations of the series mechanism, the target dynamic equation of the parallel mechanism in the series configuration can be determined, which is the aforementioned M(q) dynamic equation. a )*q a +C(q a q a )*q a +G(q a )=τ a .
[0084] Of course, it should be noted that, in conjunction with the foregoing explanations, by selecting appropriate parallel mechanisms, such as parallel mechanisms with similar dynamic behavior to series mechanisms, and performing equivalent series connection of their dynamic equations, the difficulty of identifying the dynamic parameters of such parallel mechanisms can be effectively simplified, while also avoiding the reduction in the accuracy of dynamic parameter identification due to errors.
[0085] S220, based on the target dynamic equation, the dynamic parameters of the target parallel mechanism are identified to obtain the equivalent control torque of the target structure in the target parallel mechanism.
[0086] By transforming the initial dynamic equations of the target parallel mechanism in parallel form into equivalent series dynamic equations using the aforementioned scheme, and fitting the dynamic parameters in the model based on actual motion data, the equivalent control torque of the target structure in the target parallel mechanism can be further identified. For example, by projecting each dynamic parameter of the end-effector's operating space of the target parallel mechanism onto the joint space of the target parallel mechanism, as described above, the control torque of the target parallel mechanism in the joint space can be solved by identifying the dynamic parameters in the target dynamic equations.
[0087] S230, based on kinematic equivalence, the equivalent control torque is converted into the control space of the target actuator of the target parallel mechanism to obtain the target control torque.
[0088] In some embodiments of this application, after identifying the equivalent control torque of the target structure based on the dynamic parameters in the equivalent series form, since the operating space of the parallel mechanism is usually the end effector, it is often necessary to further map the control torque in the joint space back to the actuator space of the parallel mechanism. Specifically, in one embodiment of this application, this can typically be achieved by using the differential motion relationship between the joint space and the operating space, that is, by using the kinematic equivalence between the joints and the end effector in the parallel mechanism to map the equivalent control torque into the control space of the target actuator of the target parallel mechanism, thereby obtaining the target control torque in the operating space.
[0089] For a clearer understanding of the above, please refer to [link / reference]. Figure 5 , Figure 5 This application provides a schematic flowchart illustrating the steps for kinematically equivalent mapping of control torque in an embodiment of the present application. Specifically, it includes steps S510 to S520:
[0090] S510, determine the mapping matrix based on the equivalent correlation between the kinematic parameters of the target structure and the kinematic parameters of the target actuator.
[0091] In this embodiment, the mapping matrix between the two spaces can be determined based on the differential motion relationship between the joint space and the operating space mentioned above, that is, the equivalent correlation between the kinematic parameters of the target structure (joint space) and the kinematic parameters of the target actuator (operating space).
[0092] For example, the Stewart platform (6 degrees of freedom) has n a=6 active joints (hydraulic cylinders), at this point a 6×6 mapping matrix can be determined, mapping the speed of the 6 cylinders to the 6-dimensional velocity of the moving platform.
[0093] S520, the equivalent control torque is processed based on the mapping matrix to transform the equivalent control torque into the control space of the target actuator of the target parallel mechanism, thereby obtaining the target control torque.
[0094] In this embodiment of the application, by processing the aforementioned effective control torque through a mapping matrix, the equivalent control torque in the joint space can be transformed back into the control space of the target actuator of the target parallel mechanism, thereby obtaining the target control torque.
[0095] Furthermore, in some embodiments of this application, based on the obtained control torque, the target parallel mechanism can be further subjected to dynamic control based on the target control torque, wherein the dynamic control includes at least one of inverse dynamic control, impedance control, and force-position hybrid control.
[0096] In the embodiments of this application, the dynamic equations of the parallel mechanism are converted into equivalent series form through a dynamic equivalence method, so as to allow the identification of the equivalent dynamic parameters of the system through the dynamic identification method of the series mechanism. Then, based on the kinematic equivalence method, the equivalent dynamic parameters are restored to the end execution space of the parallel mechanism. This can avoid the process of directly solving the complex high-dimensional nonlinear dynamic equations of the parallel mechanism, simplify the identification difficulty of the dynamic parameters of the parallel mechanism, and thus improve the dynamic control efficiency of the parallel mechanism.
[0097] Furthermore, to better implement the dynamic parameter identification method provided in the embodiments of this application, this application also provides a dynamic parameter identification device based on the dynamic parameter identification method provided in this application. For details, please refer to... Figure 6 , Figure 6 This application provides a schematic diagram of the structure of a dynamic parameter identification device, specifically including:
[0098] The dynamic equivalence module 610 is used to transform the initial dynamic equations of the target parallel mechanism in parallel form into the target dynamic equations in series form based on the equivalence of dynamic parameters.
[0099] The identification module 620 is used to identify the dynamic parameters of the target parallel mechanism based on the target dynamic equation, and to obtain the equivalent control torque of the target structure in the target parallel mechanism;
[0100] The kinematic equivalence module 630 is used to convert the equivalent control torque into the control space of the target actuator of the target parallel mechanism based on kinematic equivalence, so as to obtain the target control torque.
[0101] In one embodiment of this application, the dynamic equivalence module 610 is further configured to acquire the dynamic behavior characteristics of the target parallel mechanism; and, when the dynamic behavior characteristics meet preset conditions, execute the step of converting the dynamic equation of the target parallel mechanism into the target dynamic equation in series form based on dynamic equivalence.
[0102] In one embodiment of this application, the dynamic equivalence module 610 is further configured to perform the step of converting the dynamic equations of the target parallel mechanism into target dynamic equations in series form based on dynamic equivalence in the following cases:
[0103] The similarity between the first structural mass distribution of the target parallel mechanism and the second structural mass distribution of the series mechanism exceeds a preset similarity threshold.
[0104] The ratio of the number of target structures moving in the first motion mode in the target parallel mechanism to the total number of structures in the target parallel mechanism exceeds a preset ratio threshold.
[0105] The coupling strength between the structures in the target parallel mechanism does not exceed a preset coupling threshold.
[0106] In one embodiment of this application, the dynamic equivalence module 610 is further configured to transform each dynamic parameter in the initial dynamic equation into an equivalent dynamic parameter in series form based on the Jacobian matrix;
[0107] Based on the equivalent dynamic parameters and the dynamic equation form of the series mechanism, the target dynamic equation of the target parallel mechanism in the series form is determined.
[0108] In one embodiment of this application, the dynamic equivalence module 610 is further configured to project each dynamic parameter of the end-operating space of the target parallel mechanism in the initial dynamic equation to the joint space of the target parallel mechanism based on the Jacobian matrix, so as to obtain the equivalent dynamic parameter of each dynamic parameter in the joint space.
[0109] In one embodiment of this application, the kinematic equivalence module 630 is further configured to determine a mapping matrix based on the equivalent correlation between the kinematic parameters of the target structure and the kinematic parameters of the target actuator; the kinematic parameters include pose parameters and / or motion parameters;
[0110] The equivalent control torque is processed based on the mapping matrix to transform the equivalent control torque into the control space of the target actuator of the target parallel mechanism, thereby obtaining the target control torque.
[0111] In one embodiment of this application, the kinematic equivalent module 630 is further configured to perform dynamic control on the target parallel mechanism based on the target control torque, wherein the dynamic control includes at least one of inverse dynamic control, impedance control, and force-position hybrid control.
[0112] In the embodiments of this application, the dynamic equations of the parallel mechanism are converted into equivalent series form through a dynamic equivalence method, so as to allow the identification of the equivalent dynamic parameters of the system through the dynamic identification method of the series mechanism. Then, based on the kinematic equivalence method, the equivalent dynamic parameters are restored to the end execution space of the parallel mechanism. This can avoid the process of directly solving the complex high-dimensional nonlinear dynamic equations of the parallel mechanism, simplify the identification difficulty of the dynamic parameters of the parallel mechanism, and thus improve the dynamic control efficiency of the parallel mechanism.
[0113] This application also provides an electronic device, Figure 7 This is a block diagram illustrating an electronic device 700 according to an exemplary embodiment. Figure 7 As shown, the electronic device 700 may include a processor 701 and a memory 702. The electronic device 700 may also include one or more of a multimedia component 703, an input / output component 704, and a communication component 705. In this embodiment, the electronic device 700 may be a device that integrates and configures the identification of dynamic parameters provided in this embodiment.
[0114] The processor 701 controls the overall operation of the electronic device 700 to complete all or part of the steps in the aforementioned method for determining dynamic parameters. The memory 702 stores various types of data to support the operation of the electronic device 700. This data may include, for example, instructions for any application or method operating on the electronic device 700, and application-related data such as contact data, sent and received messages, pictures, audio, video, etc. The memory 702 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. Multimedia component 703 may include a screen and an audio component. The screen may be, for example, a touchscreen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in memory 702 or transmitted via communication component 705. The audio component also includes at least one speaker for outputting audio signals. I / O component 704 provides an interface between processor 701 and other interface modules, such as a keyboard, mouse, buttons, etc. These buttons may be virtual or physical buttons. Communication component 705 is used for wired or wireless communication between the electronic device 700 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IoT, eMTC, or other 5G technologies, or combinations thereof, is not limited here. Therefore, the corresponding communication component 705 may include: a Wi-Fi module, a Bluetooth module, an NFC module, etc.
[0115] In an exemplary embodiment, the electronic device 700 may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the aforementioned method for identifying dynamic parameters.
[0116] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the dynamic parameter identification method provided in any of the above embodiments.
[0117] This application also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, it enables the computer program product to implement the dynamic parameter identification method provided in any of the above embodiments.
[0118] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A method for identifying dynamic parameters, characterized in that, include: Based on the equivalence of dynamic parameters, the initial dynamic equations of the target parallel mechanism in parallel form are transformed into target dynamic equations in series form; Based on the target dynamic equation, the dynamic parameters of the target parallel mechanism are identified to obtain the equivalent control torque of the target structure in the target parallel mechanism; Based on kinematic equivalence, the equivalent control torque is converted into the control space of the target actuator of the target parallel mechanism to obtain the target control torque.
2. The method according to claim 1, characterized in that, The method further includes: Obtain the dynamic behavior characteristics of the target parallel mechanism; When the dynamic behavior characteristics meet the preset conditions, the step of converting the dynamic equations of the target parallel mechanism into the target dynamic equations in series form based on dynamic equivalence is performed.
3. The method according to claim 2, characterized in that, The aforementioned dynamic behavior characteristics include structural mass distribution, structural motion mode, and coupling strength between structures; The dynamic behavior characteristics satisfy at least one of the following preset conditions: The similarity between the first structural mass distribution of the target parallel mechanism and the second structural mass distribution of the series mechanism exceeds a preset similarity threshold. The ratio of the number of target structures moving in the first motion mode in the target parallel mechanism to the total number of structures in the target parallel mechanism exceeds a preset ratio threshold. The coupling strength between the structures in the target parallel mechanism does not exceed a preset coupling threshold.
4. The method according to claim 1, characterized in that, The process of transforming the initial dynamic equations of the target parallel mechanism into target dynamic equations in series form based on equivalent dynamic parameters includes: Based on the Jacobian matrix, each dynamic parameter in the initial dynamic equation is transformed into an equivalent dynamic parameter in series form; Based on the equivalent dynamic parameters and the dynamic equation form of the series mechanism, the target dynamic equation of the target parallel mechanism in the series form is determined.
5. The method according to claim 4, characterized in that, The process of transforming each dynamic parameter in the initial dynamic equation into an equivalent dynamic parameter in series form based on the Jacobian matrix includes: Based on the Jacobian matrix, each dynamic parameter of the end-operating space of the target parallel mechanism in the initial dynamic equation is projected to the joint space of the target parallel mechanism to obtain the equivalent dynamic parameter of each dynamic parameter in the joint space.
6. The method according to claim 1, characterized in that, The process of converting the equivalent control torque based on kinematic equivalence into the control space of the target actuator of the target parallel mechanism to obtain the target control torque includes: A mapping matrix is determined based on the equivalent correlation between the kinematic parameters of the target structure and the kinematic parameters of the target actuator; the kinematic parameters include pose parameters and / or motion parameters. The equivalent control torque is processed based on the mapping matrix to transform the equivalent control torque into the control space of the target actuator of the target parallel mechanism, thereby obtaining the target control torque.
7. The method according to any one of claims 1 to 6, characterized in that, The method further includes: The target parallel mechanism is dynamically controlled based on the target control torque, and the dynamic control includes at least one of inverse dynamic control, impedance control, and force-position hybrid control.
8. A device for identifying dynamic parameters, characterized in that, include: The dynamic equivalence module is used to transform the initial dynamic equations of the target parallel mechanism in parallel form into the target dynamic equations in series form based on the equivalence of dynamic parameters; The identification module is used to identify the dynamic parameters of the target parallel mechanism based on the target dynamic equation, and to obtain the equivalent control torque of the target structure in the target parallel mechanism; The kinematic equivalence module is used to convert the equivalent control torque into the control space of the target actuator of the target parallel mechanism based on kinematic equivalence, so as to obtain the target control torque.
9. An electronic device, characterized in that, The electronic device includes: One or more processors; Memory; and One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement the method for identifying the dynamic parameters according to any one of claims 1 to 7.
10. A computer-readable storage medium, characterized in that, It stores a computer program, which is loaded by a processor to execute the method for identifying the dynamic parameters according to any one of claims 1 to 7.