Flexible joint system control method and device, computer equipment and storage medium

Abstract

The invention relates to a flexible joint system control method and device, computer equipment and a storage medium. The method comprises the following steps: acquiring a basic proportional gain of a position ring in the flexible joint system, and a current load rotational inertia and a current output torque of the flexible joint system; querying a target load compensation gain matched with the current load rotational inertia and a target torque compensation gain matched with the current output torque; wherein the target load compensation gain and the target torque compensation gain are control gains which enable the bandwidth corresponding to a preset amplitude-frequency characteristic curve of the flexible joint system to be maximum and the resonance peak value of the preset amplitude-frequency characteristic curve to be within a preset amplitude range; and controlling the flexible joint system according to the target load compensation gain, the target torque compensation gain and the basic proportional gain. By adopting the method, the flexible joint system can be accurately controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automatic control, in particular to a flexible joint system control method and device, computer equipment and storage medium. BACKGROUND

[0002] With the development of industrial automation and intelligent manufacturing, high-performance robots have higher requirements for motion accuracy, dynamic response speed and load adaptability. The robot joint system usually adopts a motor driving through a high reduction ratio reducer, forming a typical flexible joint system. However, the corresponding inherent resonance frequency of the flexible joint system and the nonlinearity and uncertainty of the dynamic parameters lead to real-time changes of the system transfer function, making it difficult for the controller of the flexible joint system to ensure robustness and stability while pursuing high bandwidth.

[0003] In the traditional technology, a gain scheduling PID (Proportional-Integral-Derivative) control strategy based on joint speed is generally used to control the flexible joint system. Specifically, the strategy dynamically adjusts the proportional gain Kp and the derivative gain Kd in the PID controller according to the real-time running speed of the robot joint through a preset function or a lookup table. The basic idea is: at low speed, increase Kp to improve positioning accuracy and anti-interference ability; at high speed, reduce Kp and Kd to avoid speed saturation and possible overshoot or oscillation, thereby ensuring the stability of the system.

[0004] However, the current flexible joint system control method is still not accurate enough. SUMMARY

[0005] Therefore, it is necessary to provide an accurate flexible joint system control method, device, computer equipment, computer readable storage medium and computer program product to solve the above technical problems.

[0006] In a first aspect, the present application provides a flexible joint system control method, comprising:

[0007] obtaining a basic proportional gain of a position loop in the flexible joint system, and a current load moment of inertia and a current output torque of the flexible joint system;

[0008] querying a target load compensation gain matched with the current load moment of inertia, and a target torque compensation gain matched with the current output torque; wherein the target load compensation gain and the target torque compensation gain are control gains that make the bandwidth of a preset amplitude-frequency characteristic curve of the flexible joint system maximum, and the resonance peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range;

[0009] The flexible joint system is controlled based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0010] In one embodiment, before querying the target load compensation gain matching the current load moment of inertia, the method further includes:

[0011] When the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is under different load conditions, the frequency of the flexible joint system is swept for each load condition to obtain the standard load compensation gain and standard load moment of inertia under the condition that the first bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system is maximized and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0012] Based on the standard load compensation gain and standard load moment of inertia corresponding to multiple load states, the first mapping relationship between load moment of inertia and load compensation gain is detected.

[0013] Query the target load compensation gain that matches the current load moment of inertia, including:

[0014] Query the target load compensation gain that matches the current load rotational inertia from the first mapping relationship.

[0015] In one embodiment, the standard load compensation gain corresponding to the multiple load states includes at least the standard no-load compensation gain corresponding to the no-load state and the standard full-load compensation gain corresponding to the full-load state, and the standard load rotational inertia corresponding to the multiple load states includes at least the standard no-load rotational inertia corresponding to the no-load state and the standard full-load rotational inertia corresponding to the full-load state.

[0016] Based on the standard load compensation gain and standard load moment of inertia corresponding to multiple load states, the first mapping relationship between the load moment of inertia and the load compensation gain is detected, including:

[0017] Based on the no-load compensation gain, no-load moment of inertia, full-load compensation gain, and full-load moment of inertia, the first mapping relationship between the load moment of inertia and the load compensation gain is detected.

[0018] In one embodiment, detecting a first mapping relationship between the load moment of inertia and the load compensation gain based on the no-load compensation gain, the no-load moment of inertia, the full-load compensation gain, and the full-load moment of inertia includes:

[0019] When the joint axis is in an unloaded state and the end is unloaded, obtain the unloaded resonant frequency corresponding to the preset amplitude-frequency characteristic curve, and when the joint axis is in an unloaded state and the end is fully loaded, obtain the full-load resonant frequency corresponding to the preset amplitude-frequency characteristic curve.

[0020] Based on the full-load compensation gain, no-load compensation gain, no-load resonant frequency and full-load resonant frequency, detect the second mapping relationship between the load compensation gain and the load resonant frequency.

[0021] Obtain the third mapping relationship between the preset load resonant frequency and the load rotational inertia;

[0022] Based on the second mapping relationship, the third mapping relationship, and the no-load moment of inertia, the first mapping relationship between the load moment of inertia and the load compensation gain is detected.

[0023] In one embodiment, before querying the target torque compensation gain that matches the current output torque, the method further includes:

[0024] When the load state at the end of the flexible joint system is the same and the joint axis of the flexible joint system is in different force postures, for each force posture, the standard output torque of the flexible joint system is detected, and the frequency of the flexible joint system is swept to obtain the standard torque compensation gain that maximizes the second bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and the resonant peak of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0025] Based on the standard output torque and standard torque compensation gain corresponding to each force-bearing posture, a fourth mapping relationship between the output torque and torque compensation gain is obtained.

[0026] Query the target torque compensation gain that matches the current output torque, including:

[0027] Query the target torque compensation gain that matches the current output torque from the fourth mapping relationship.

[0028] In one embodiment, obtaining the basic proportional gain of the position loop in the flexible joint system includes:

[0029] When the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is in an unloaded state, the frequency of the flexible joint system is swept to obtain the basic proportional gain that maximizes the third bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0030] Secondly, this application also provides a flexible joint system control device, comprising:

[0031] The acquisition module is used to acquire the basic proportional gain of the position loop in the flexible joint system, as well as the current load moment of inertia and current output torque of the flexible joint system.

[0032] The query module is used to query the target load compensation gain matching the current load rotational inertia and the target torque compensation gain matching the current output torque. The target load compensation gain and the target torque compensation gain are both control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0033] The control module is used to control the flexible joint system based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0034] Thirdly, this application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to perform the following steps:

[0035] Obtain the basic proportional gain of the position loop in the flexible joint system, as well as the current load moment of inertia and current output torque of the flexible joint system;

[0036] Query the target load compensation gain that matches the current load moment of inertia, and the target torque compensation gain that matches the current output torque; where the target load compensation gain and the target torque compensation gain are both control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0037] The flexible joint system is controlled based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0038] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the following steps:

[0039] Obtain the basic proportional gain of the position loop in the flexible joint system, as well as the current load moment of inertia and current output torque of the flexible joint system;

[0040] Query the target load compensation gain that matches the current load moment of inertia, and the target torque compensation gain that matches the current output torque; where the target load compensation gain and the target torque compensation gain are both control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0041] The flexible joint system is controlled based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0042] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, performs the following steps:

[0043] Obtain the basic proportional gain of the position loop in the flexible joint system, as well as the current load moment of inertia and current output torque of the flexible joint system;

[0044] Query the target load compensation gain that matches the current load moment of inertia, and the target torque compensation gain that matches the current output torque; where the target load compensation gain and the target torque compensation gain are both control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0045] The flexible joint system is controlled based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0046] The aforementioned flexible joint system control method, device, computer equipment, computer-readable storage medium, and computer program product, throughout the entire process, effectively compensate for the impact of load rotational inertia changes on system stability by introducing a target load compensation gain that matches the current load rotational inertia, ensuring that the system maintains stable high dynamic performance under different load rotational variables. Simultaneously, by introducing a target torque compensation gain that matches the current output torque, it indirectly compensates for the nonlinear changes caused by the reducer stiffness, thereby eliminating performance fluctuations caused by stiffness changes and enhancing the system's robustness and consistency. Furthermore, based on the target load compensation gain matched by the current load rotational inertia, when... When the target torque compensation gain and the base proportional gain of the front output torque matching are used to control the flexible joint system, since both the target load compensation gain and the target torque compensation gain are control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range, the flexible joint system under different working conditions can satisfy the requirement that the preset amplitude-frequency characteristic curve is within the maximum bandwidth and the resonant peak value is within the preset amplitude range. This solves the technical problem of poor adaptability of the proportional gain of the position loop to load and stiffness changes and conservative dynamic performance in the prior art, and improves the accuracy of adaptive control of the flexible joint system. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a diagram illustrating the application environment of a flexible joint system control method in one embodiment.

[0049] Figure 2 This is a flowchart illustrating a control method for a flexible joint system in one embodiment;

[0050] Figure 3 This is a flowchart illustrating the control method for a flexible joint system in another embodiment;

[0051] Figure 4 This is a schematic diagram illustrating the relationship between load compensation gain and load moment of inertia under various load conditions in one embodiment.

[0052] Figure 5 This is a schematic diagram illustrating the fourth mapping relationship between output torque and torque compensation gain in one embodiment;

[0053] Figure 6 This is a structural block diagram of a flexible joint system control device in one embodiment;

[0054] Figure 7 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0056] A flexible joint system refers to a robot joint in which a motor drives a load through a high-reduction-ratio reducer (such as a harmonic reducer). Due to the elasticity of the reducer gears and structure, it can be dynamically modeled as a two-mass system coupled by elasticity and stiffness. The dynamic characteristics of a flexible joint system are a key factor affecting robot performance, mainly reflected in:

[0057] 1. System inherent resonance: The elastic coupling between the drive side and the load side forms an inherent resonant frequency, which limits the maximum control bandwidth that the system can achieve.

[0058] 2. Uncertainty of dynamic parameters: (1) The moment of inertia of the load changes as the robot performs tasks and grasps objects; (2) The stiffness of the reducer is a nonlinear parameter that changes with the transmitted torque and the time of use.

[0059] The nonlinearity and uncertainty of these parameters lead to real-time changes in the system transfer function, making it difficult for the controller of the flexible joint system to guarantee robustness and stability while pursuing high bandwidth.

[0060] In traditional technologies, a gain-scheduled PID (Proportional-Integral-Derivative) control strategy based on joint velocity is generally used to control flexible joint systems. Specifically, this strategy dynamically adjusts the proportional gain K in the PID controller according to the real-time running speed of the robot joint using a preset function or lookup table. p and differential gain K d The basic idea is: when running at low speed, increase K. p To improve positioning accuracy and anti-interference capability; to reduce K during high-speed operation. p and K d To avoid overshoot or oscillation that may result from speed saturation, thus ensuring system stability.

[0061] Based on the closest existing technology mentioned above, the main technical drawback of current flexible joint system control methods is:

[0062] 1. Inability to adapt to changes in key dynamic parameters: Its gain value is related to the core dynamic parameter (load moment of inertia J) that affects the system's resonant frequency and bandwidth. L and the actual working stiffness K of the reducer S There is no direct, adaptive relationship between them.

[0063] 2. Inherent contradictions and limitations of gain tuning: Traditional fixed gain tuning requires a compromise between performance and robustness. Specifically, this manifests in:

[0064] If a high gain optimized for light load conditions is used (in pursuit of response speed), when the system operates under heavy load or increased stiffness conditions, the system's natural resonant frequency will decrease, and the high gain will more easily excite resonance, resulting in an excessively high closed-loop resonant peak, or even system instability.

[0065] If a conservative low gain optimized for heavy-load conditions is adopted (to ensure robustness), this gain will be overly conservative when the system operates under light load or reduced stiffness conditions. This will significantly reduce the closed-loop bandwidth of the system, making it unable to realize the maximum dynamic performance potential under light load, and sacrificing response speed and tracking accuracy.

[0066] 3. Lack of quantified frequency domain optimization objectives: Existing technologies lack a clear and quantified frequency domain performance indicator for gain tuning, which makes the gain adjustment process lack precise guidance and cannot guarantee that the system always operates at the optimal dynamic margin.

[0067] To address this, this application provides a control method for a flexible joint system. Throughout the process, by introducing a target load compensation gain matching the current load moment of inertia, the impact of load moment of inertia changes on system stability is effectively compensated, ensuring the system maintains stable high dynamic performance under different load rotation variables. Simultaneously, by introducing a target torque compensation gain matching the current output torque, the nonlinear changes caused by the reducer stiffness are indirectly compensated, thereby eliminating performance fluctuations caused by stiffness changes and enhancing the system's robustness and consistency. Furthermore, when controlling the flexible joint system based on the target load compensation gain matching the current load moment of inertia, the target torque compensation gain matching the current output torque, and the basic proportional gain, since both the target load compensation gain and the target torque compensation gain are control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure the resonant peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range, the flexible joint system under different operating conditions can satisfy the requirement that the preset amplitude-frequency characteristic curve is within the maximum bandwidth and the resonant peak value is within the preset amplitude range. This solves the technical problem of poor adaptability of the position loop proportional gain to load and stiffness changes and conservative dynamic performance in the prior art, improving the accuracy of adaptive control of the flexible joint system.

[0068] The flexible joint system control method provided in this application embodiment can be applied to, for example... Figure 1 In the application environment shown, terminal 102 communicates with controller 106 of flexible joint system 104 via a network. A data storage system can store the data that controller 106 needs to process. The data storage system can be integrated onto controller 106 or located in the cloud or on other network servers.

[0069] The user triggers a flexible joint system control control for the flexible joint system 104 on the flexible joint system control interface of terminal 102. Terminal 102 responds to the trigger request of the flexible joint system control control, generates a flexible joint system control request, and sends the flexible joint system control request to the controller 106 of the flexible joint system 104. The controller 106 obtains the basic proportional gain of the position loop in the flexible joint system, as well as the current load moment of inertia and the current output torque of the flexible joint system; it queries the target load compensation gain matching the current load moment of inertia and the target torque compensation gain matching the current output torque; wherein, the target load compensation gain and the target torque compensation gain are both control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range; the flexible joint system is controlled according to the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0070] The terminal 102 can be, but is not limited to, various personal computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. IoT devices can include smart speakers, smart TVs, smart air conditioners, smart in-vehicle systems, and projection devices. Portable wearable devices can include smartwatches, smart bracelets, and head-mounted displays. Head-mounted displays can be virtual reality (VR) devices, augmented reality (AR) devices, and smart glasses. The controller 106 can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services.

[0071] In one exemplary embodiment, such as Figure 2 As shown, a control method for a flexible joint system is provided, which can be applied to... Figure 1 The following explanation uses controller 106 as an example. Specifically:

[0072] S200, obtain the basic proportional gain of the position loop in the flexible joint system, as well as the current load moment of inertia and current output torque of the flexible joint system.

[0073] The flexible joint system is an electromechanical system integrating a flexible joint shaft and closed-loop control. Its core feature is the inclusion of elastically deformable components (such as elastomers or flexible shafts) at the joint, enabling flexible buffering and precise force / position control while transmitting motion and torque. The flexible joint system employs a classic three-loop structure: a current loop (innermost loop), a velocity loop (middle loop), and a position loop (outermost loop). The current loop, determined by the drive hardware, has the highest bandwidth and is independent of the load or reducer. The velocity loop typically uses a proportional-integral controller, with a bandwidth usually designed to be 5 to 10 times that of the position loop. The position loop generally uses proportional control; however, it's worth noting that the differential controller K... d K-band can easily introduce and amplify high-frequency noise, therefore it is rarely used alone in noise-sensitive servo systems, especially in the position loop. dAlternatively, no scheduling may be performed. The load moment of inertia is the equivalent moment of inertia of the robot's load side (including the end effector and the grasped object) referred to the joint axis, and is a key parameter affecting the system's resonant frequency. The output torque of a flexible joint system refers to the torque output from its load end to drive the load to complete rotation or force application. In this application, for flexible joint systems with torque sensors, the current output torque can be directly detected using the joint torque sensor. For flexible joint systems without torque sensors, the current steady-state current information can be used instead of detecting the current output torque. The current steady-state current information can approximate the current output torque, and both serve the same purpose. The steady-state current information is the current data of the drive motor when the system reaches a stable operating state (such as uniform rotation or stationary positioning).

[0074] Specifically, in cascade control, the final bandwidth of the system is mainly determined by the outermost loop (position loop). Therefore, adjusting the proportional gain of the position loop in the flexible joint system is the most effective way to influence the final dynamic response speed and resonance suppression capability of the flexible joint system. Thus, the basic proportional gain of the position loop in the flexible joint system can be obtained in advance, and by adjusting the basic proportional gain of the position loop in real time, the closed-loop system can achieve the maximum stable bandwidth under different load moments of inertia and output torques, and the resonance peak of the preset amplitude-frequency characteristic curve can be constrained within a predetermined optimal dynamic margin range (e.g., 0dB~0.5dB).

[0075] S400 queries the target load compensation gain that matches the current load moment of inertia and the target torque compensation gain that matches the current output torque.

[0076] Among them, the target load compensation gain and the target torque compensation gain are both control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range. The resonant peak value is the highest gain value (usually in dB) that appears at the resonant frequency of the amplitude-frequency characteristic of the closed-loop system frequency response (Bode diagram).

[0077] Load compensation gain is used to compensate for the effect of changes in load rotational inertia on the system's resonant frequency. Torque compensation gain is used to compensate for the effect of changes in joint output torque (characterized by output torque) on the reducer stiffness. Here, stiffness specifically refers to the reducer's equivalent stiffness, which is not constant but changes nonlinearly with the output torque transmitted by the joint. It is a key dynamic parameter affecting the system's resonant frequency and damping.

[0078] Specifically, a first mapping relationship between the load's moment of inertia and the load compensation gain is obtained in advance, and the target load compensation gain matching the current load's moment of inertia is queried based on this mapping relationship. Simultaneously, a second mapping relationship between the output torque and the torque compensation gain is obtained in advance, and the target torque compensation gain matching the current output torque is queried based on this mapping relationship.

[0079] Furthermore, when obtaining the first mapping relationship between the load rotational inertia and the load compensation gain, and the second mapping relationship between the output torque and the torque compensation gain, each load compensation gain is a control gain that maximizes the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system under the corresponding load rotational inertia, and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range. Similarly, each torque compensation gain is a control gain that maximizes the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system under the corresponding output torque, and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0080] In one embodiment, this application can also directly query the target torque compensation gain that matches the output torque by obtaining the estimated output torque.

[0081] The S600 controls the flexible joint system based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0082] Specifically, based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain, the basic proportional gain is scaled and adjusted in real time to obtain the proportional gain. The flexible joint system is then controlled according to this proportional gain. Furthermore, the proportional gain is the product of a basic proportional gain and two independent compensation gains, and its expression can be: That is, the compensation gain K is based on the target load. PL Target torque compensation gain K PC Compared with the basic proportional gain P P1 The product of these terms yields the proportional gain. Wherein, the target load compensation gain K... PL The target torque compensation gain K reflects the effect of the load's moment of inertia on the proportional gain. PC It reflects the effect of joint output torque on proportional gain.

[0083] It should be explained that the maximum stable bandwidth is a key objective for achieving high dynamic performance. A higher system bandwidth means a faster response speed of the joint to control commands, reducing hysteresis errors and thus achieving smaller tracking errors and higher dynamic accuracy. Therefore, this application adjusts the basic proportional gain based on the target load compensation gain and target torque compensation gain, ensuring that the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system is maximized and the resonant peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range. This allows for achieving the optimization objective of maximum stable bandwidth, constrained by the requirement that the resonant peak value of the preset amplitude-frequency characteristic curve be within a preset amplitude range (e.g., 0~0.5dB).

[0084] In the aforementioned flexible joint system control method, throughout the process, by introducing a target load compensation gain that matches the current load rotational inertia, the influence of load rotational inertia changes on system stability is effectively compensated, ensuring that the system maintains stable high dynamic performance under different load rotational variables. Simultaneously, by introducing a target torque compensation gain that matches the current output torque, the nonlinear changes caused by the reducer stiffness are indirectly compensated, thereby eliminating performance fluctuations caused by stiffness changes and enhancing the system's robustness and consistency. Furthermore, when controlling the flexible joint system based on the target load compensation gain matching the current load rotational inertia, the target torque compensation gain matching the current output torque, and the basic proportional gain, since both the target load compensation gain and the target torque compensation gain are control gains that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range, the flexible joint system under different operating conditions can satisfy the requirement that the preset amplitude-frequency characteristic curve is within the maximum bandwidth and the resonant peak value is within the preset amplitude range. This solves the technical problem of poor adaptability of the position loop proportional gain to load and stiffness changes and conservative dynamic performance in the prior art, improving the accuracy of adaptive control of the flexible joint system.

[0085] In one exemplary embodiment, such as Figure 3 As shown, prior to S400, the method also includes:

[0086] S320, under the condition that the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is under different load conditions, the frequency of the flexible joint system is swept for each load condition to obtain the standard load compensation gain and standard load moment of inertia under the condition that the first bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system is maximized and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0087] S340 detects the first mapping relationship between the load rotational inertia and the load compensation gain based on the standard load compensation gain and standard load rotational inertia corresponding to multiple load states.

[0088] S400 includes: querying the target load compensation gain that matches the current load moment of inertia from the first mapping relationship.

[0089] In a flexible joint system, the end effector is the final actuating component that directly interacts with the work object or environment, serving as the ultimate carrier of the system's power output. The joint axis of a flexible joint system is in a stress-free posture. This means that by adjusting the spatial angle of the joint, the joint axis (and its core transmission structure) is not subjected to structural forces (such as tension, torsion, or compression) generated by load or its own weight. Only the dynamic mechanical effects of load inertia are retained, avoiding structural forces that could affect system characteristics or cause damage. The core effect of the end effector of a flexible joint system under different load states is to change the system's moment of inertia, rather than directly applying structural forces to the joint axis. For example, the greater the load, the greater the overall inertia of the system. However, as long as the posture is designed reasonably (e.g., when the end effector is loaded with different weights, keeping the joint in a horizontal posture to avoid the direct effect of gravity on the joint), the joint axis will not experience additional forces, nor will its inherent stiffness be changed. In this state, the load gravity is perpendicular to the rotation axis of the transmission shaft, and will not generate torsional or tensile forces on the joint axis. The joint axis is in a state free from structural forces.

[0090] Specifically, to ensure that the stiffness of the flexible joint system remains unchanged and to test the effect of the load on resonance separately, the end of the flexible joint system can be controlled to be in different load states while the joint axis is in an unloaded posture. At this time, the flexible joint system is mainly affected by the end inertia, eliminating other interference factors, such as the force interference of the joint axis. Then, for each load state, a position closed-loop frequency sweep test is performed on the flexible joint system.

[0091] The location closed-loop frequency sweep test process in this embodiment includes:

[0092] (1) When the joint axis of the flexible joint system is in a stress-free state and the end of the flexible joint system is under a certain load state, apply a frequency sweep command.

[0093] (2) Observe or measure the closed-loop frequency response in the amplitude-frequency characteristic curve of the system.

[0094] (3) Iteratively adjust the proportional gain. The adjustment of the proportional gain will affect the bandwidth and resonant peak of the amplitude-frequency response curve. It is necessary to iteratively find the balance point until the bandwidth reaches the maximum. At the same time, ensure that the resonant peak on the amplitude-frequency response curve is precisely constrained within the preset amplitude range, that is, the predetermined range of 0-0.5dB.

[0095] (4) The proportional gain that satisfies the constraints in (3) is taken as the optimal gain under the current load condition, i.e., the standard load compensation gain. Based on the resonant frequency that satisfies the constraints in (3), the corresponding standard load moment of inertia is obtained. Among them, the resonant frequency is the inherent vibration frequency of the flexible joint system. When the system is excited near this frequency, the amplitude will increase significantly. This frequency limits the maximum stable bandwidth that the system can achieve. In practical applications, the load compensation gain corresponding to the no-load state is 1.

[0096] (5) Based on the standard load compensation gain and standard load rotational inertia corresponding to multiple load states respectively, detect the first mapping relationship between load rotational inertia and load compensation gain.

[0097] Test results show that, for the same gain, the larger the load, the lower the resonant frequency and the higher the resonant peak value of the system.

[0098] In practical applications, the first mapping relationship between the load moment of inertia and the load compensation gain can be represented by an analytical function, or it can be implemented by a one-dimensional lookup table and linear interpolation.

[0099] Furthermore, when controlling the flexible joint system, the current load rotational inertia can be obtained first, and then the target load compensation gain matching the current load rotational inertia can be queried from the first mapping relationship. Based on the target load compensation gain, the proportional gain of the position loop in the flexible joint system can be adjusted.

[0100] In the above embodiments, by constructing the joint axis of the flexible joint system in a stress-free posture and the end of the flexible joint system in different load states, the first mapping relationship between the load rotational inertia and the load compensation gain is mainly affected by the end inertia, eliminating other interference factors and accurately focusing on the effect of inertia on the dynamic characteristics of the system.

[0101] In an exemplary embodiment, the standard load compensation gain corresponding to the multiple load states includes at least the standard no-load compensation gain corresponding to the no-load state and the standard full-load compensation gain corresponding to the full-load state, and the standard load rotational inertia corresponding to the multiple load states includes at least the standard no-load rotational inertia corresponding to the no-load state and the standard full-load rotational inertia corresponding to the full-load state.

[0102] Based on the standard load compensation gain and standard load moment of inertia corresponding to multiple load states, the first mapping relationship between the load moment of inertia and the load compensation gain is detected, including:

[0103] Based on the no-load compensation gain, no-load moment of inertia, full-load compensation gain, and full-load moment of inertia, the first mapping relationship between the load moment of inertia and the load compensation gain is detected.

[0104] Specifically, in this embodiment, this application determines two boundary compensation gains through closed-loop tuning under boundary load conditions, thereby obtaining a first mapping relationship between the load rotational inertia and the load compensation gain. That is, when the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is in an unloaded or fully loaded state, the standard unload compensation gain corresponding to the unloaded state, the standard full load compensation gain corresponding to the full load state, the standard unload rotational inertia corresponding to the unloaded state, and the standard full load rotational inertia corresponding to the full load state are obtained. Then, based on the unload compensation gain, the unload rotational inertia, the full load compensation gain, and the full load rotational inertia, the first mapping relationship between the load rotational inertia and the load compensation gain can be obtained.

[0105] For example, the expression for the first mapping relationship between the load moment of inertia and the load compensation gain is as follows:

[0106]

[0107] Among them, the lower limit of the inertia range (standard no-load rotational inertia) J L1 =27.730078 kg·m 2 Standard no-load compensation gain K PL1 = 1, Upper limit of inertia range (standard no-load rotational inertia) J L2 = 45.476912 kg·m 2 Standard full-load compensation gain K PL2 = 0.75. At this point, the load compensation gain K under each load condition is... PL With load rotational inertia J L The relationship between them is as follows: Figure 4 As shown in the figure, it can be seen that with the change in the moment of inertia J of the load... L The increase of load compensation gain K PL Monotonically decreasing.

[0108] In the above embodiments, the connection and disconnection of the first mapping relationship between the load rotational inertia and the load compensation gain need to determine the upper and lower limits of the load inertia range. Therefore, by setting the load state for detecting the first mapping relationship to an unloaded state and a full-load state, the first mapping relationship between the load rotational inertia and the load compensation gain can be accurately defined through two boundary conditions.

[0109] In an exemplary embodiment, detecting a first mapping relationship between the load moment of inertia and the load compensation gain based on the no-load compensation gain, the no-load moment of inertia, the full-load compensation gain, and the full-load moment of inertia includes:

[0110] When the joint axis is in a stress-free posture and the end is unloaded, the no-load resonant frequency corresponding to the preset amplitude-frequency characteristic curve is obtained; when the joint axis is in a stress-free posture and the end is fully loaded, the full-load resonant frequency corresponding to the preset amplitude-frequency characteristic curve is obtained. Based on the full-load compensation gain, full-load moment of inertia, no-load resonant frequency, and full-load resonant frequency, a second mapping relationship between the load compensation gain and the load resonant frequency is detected. A third mapping relationship between the preset load resonant frequency and the load moment of inertia is obtained. Based on the second mapping relationship, the third mapping relationship, the no-load compensation gain, and the no-load moment of inertia, a first mapping relationship between the load moment of inertia and the load compensation gain is detected.

[0111] The resonant frequency is the input signal frequency corresponding to the peak value of the amplitude-frequency response curve of the flexible joint system under frequency sweep excitation. The peak value is the difference between the amplitude at the resonant frequency and the low-frequency band (or reference amplitude) in the amplitude-frequency response curve. In frequency sweep testing, the peak value corresponds to a resonant frequency, and the two are a dual description of the same dynamic phenomenon: "frequency" and "amplitude".

[0112] Specifically, the load compensation gain is essentially used to compensate for the influence of the load rotational inertia on the system resonant frequency. Therefore, when the joint shaft is in an unloaded state and the end is unloaded, it is also necessary to obtain the unloaded resonant frequency corresponding to the preset amplitude-frequency characteristic curve. Similarly, when the joint shaft is in an unloaded state and the end is fully loaded, it is also necessary to obtain the full-load resonant frequency corresponding to the preset amplitude-frequency characteristic curve.

[0113] Furthermore, based on the full-load compensation gain, full-load moment of inertia, no-load resonant frequency and full-load resonant frequency, the second mapping relationship between the load compensation gain and the load resonant frequency is detected. Combined with the third mapping relationship between the load resonant frequency and the load moment of inertia obtained in advance, and the no-load compensation gain and the no-load moment of inertia, the first mapping relationship between the load moment of inertia and the load compensation gain is calculated.

[0114] For example, assume the speed reducer stiffness is K. s Given the no-load compensation gain P P1 The no-load resonant frequency is f ar1 Due to its gain determined according to the tuning principle, the no-load compensation gain K PL1 Defined as 1. With the joint axis in an unloaded state and the end effector under full load, position and velocity closed-loop frequency sweeps are performed. According to the closed-loop tuning principle, the full-load compensation gain is K. PL2 The full-load resonant frequency is f ar2 Based on the relationship between the resonant frequency and the position closed-loop resonant peak value, the load compensation gain K... PLThe calculation formula is as follows:

[0115]

[0116] The above formula can be expressed as the load compensation gain K. PL The second mapping relationship between the load resonant frequency and f ar K is the resonant frequency under the current load. h It is a constant. .

[0117] Load resonant frequency f ar With load rotational inertia J L The third mapping relationship between them is as follows:

[0118]

[0119] Based on the second and third mapping relationships, and the no-load moment of inertia, the first mapping relationship between the load moment of inertia and the load compensation gain can be obtained as follows:

[0120]

[0121] In the above embodiments, by introducing the resonant frequency under each load condition, as well as the preset third mapping relationship between the load resonant frequency and the load moment of inertia, and the second mapping relationship between the load compensation gain and the load resonant frequency, the first mapping relationship between the load moment of inertia and the load compensation gain can be accurately detected.

[0122] In an exemplary embodiment, before querying the target torque compensation gain matching the current output torque, the method further includes: under the condition that the load state of the end of the flexible joint system is the same and the joint axis of the flexible joint system is in different force postures, for each force posture, detecting the standard output torque of the flexible joint system, and performing frequency sweeping on the flexible joint system to obtain the standard torque compensation gain that maximizes the second bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range; and obtaining a fourth mapping relationship between the output torque and the torque compensation gain according to the standard output torque and the standard torque compensation gain corresponding to each force posture.

[0123] Query the target torque compensation gain that matches the current output torque, including: querying the target torque compensation gain that matches the current output torque from the fourth mapping relationship.

[0124] Among them, the torque compensation gain is used to compensate for the influence of changes in joint output torque (characterized by output torque) on the stiffness of the reducer.

[0125] Specifically, under the same load moment of inertia, as the output torque (or steady-state current I) increases, the system's stiffness, resonant frequency, and damping will all increase.

[0126] Therefore, when the load state at the end of the flexible joint system is the same (e.g., both are under full load) and the joint axis of the flexible joint system is in different force postures (e.g., the joint is in 0° to 90°), for each force posture, the standard output torque of the flexible joint system is detected, and a position closed-loop frequency sweep is performed on the flexible joint system to manually tune an optimal standard torque compensation gain. This standard torque compensation gain maximizes the second bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensures that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0127] Finally, the fourth mapping relationship between the output torque and the torque compensation gain under all force postures is obtained. In the subsequent actual control process of the flexible joint system, the current output torque is first obtained, and then the target torque compensation gain matching the current output torque is queried from the fourth mapping relationship in order to adjust the basic proportional gain.

[0128] In one embodiment, the steps of location closed-loop frequency sweep are as follows:

[0129] (1) When the ends of the flexible joint system are all under full load and the joint axes of the flexible joint system are in different stress postures, apply a frequency sweep command.

[0130] (2) Observe or measure the closed-loop frequency response in the amplitude-frequency characteristic curve of the system.

[0131] (3) Iteratively adjust the proportional gain. The adjustment of the proportional gain will affect the bandwidth and resonant peak of the amplitude-frequency response curve. It is necessary to iteratively find the balance point until the bandwidth reaches the maximum. At the same time, ensure that the resonant peak on the amplitude-frequency response curve is precisely constrained within the preset amplitude range, that is, the predetermined range of 0-0.5dB.

[0132] The proportional gain in (4) and (3) eliminates the interference of the load state. Therefore, the proportional gain that satisfies the constraint in (3) is taken as the optimal proportional gain under the current force posture.

[0133] (5) According to K PC = Pp / (P p1 K PL This formula (a variation of the proportional gain Pp formula, i.e., proportional gain Pp = base proportional gain P) p1 Standard load compensation gain K PL • Standard torque compensation gain), where K PL The calibration was completed based on two boundary conditions: no-load and full-load conditions.

[0134] This process transforms the quantization constraints in the frequency domain into actual gain values, which are used to construct a fourth mapping relationship between the output torque and the torque compensation gain under different force postures.

[0135] In practical applications, the position closed-loop frequency sweep test of this application can be replaced by an equivalent frequency response analysis method.

[0136] In one embodiment, the fourth mapping relationship h(I) between the output torque and the torque compensation gain is a monotonically increasing function, which can be fitted using a nonlinear function or by linear interpolation lookup table method. The standard torque compensation gain K also needs to be considered. PC The saturation limit. Its expression is:

[0137]

[0138] Among them, K PCmax Standard torque compensation gain K PC The maximum value of the saturation limit, 1 is the standard torque compensation gain K. PC The minimum value of the saturation limit.

[0139] Taking the fourth mapping relationship as a table as an example, for a flexible joint system without a torque sensor, the standard torque compensation gain K is determined using a piecewise linear interpolation method based on a lookup table. PC This ensures monotonically increasing properties and stability.

[0140] 1. Segmented lookup table: K PC It is defined by a set of discrete measured data points (Current_n, KPCValues_n). These data points are obtained by manually tuning the proportional gain P under different steady-state currents. P It was obtained by constraining the resonant peak value to be less than 0.5dB.

[0141] 2. Linear interpolation: For the absolute value of the real-time current |I|, K PC Calculated using the following piecewise linear interpolation formula:

[0142] Core logic: If |I| is within the lookup table range [Current_n, Current_n+1], then K PC Obtained through linear interpolation.

[0143] Limiting and extrapolation: If |I| is less than the minimum value Current_1, then K PC Take the lower bound KPCValues_1; if |I| is greater than the maximum value Current_end, then K PC Saturation is determined by taking the upper limit of KPCValues_end.

[0144] 3. Real-time filtering: To eliminate the real-time current signal I and its calculated K PC The resulting high-frequency noise and abrupt changes are addressed by using a second-order Butterworth low-pass filter for K. PC The sequence is subjected to zero-phase filtering to ensure the smoothness and robustness of gain adjustment and to avoid introducing additional phase hysteresis and high-frequency noise into the control loop.

[0145] The final fourth mapping relationship between the output torque and the torque compensation gain is as follows: Figure 5 As shown, within the amplitude limit, the torque compensation gain increases monotonically with the output torque.

[0146] It should be noted that the standard torque compensation gain K... PC Determination of K: PC The lookup table data (or fitting function) is the gain amplification factor K under the same load conditions (e.g., under a full load of 8KG, by changing the joint angle (force posture) to test different output torques or steady-state currents I (current and output torque are consistent). PC Yes, it is certain. Theoretically, as long as the load is large enough (e.g., fully loaded) to generate a sufficiently large range of torques at different angles, K can be accurately captured. PC The variation law of K with torque. PC This reflects the impact of the reducer's stiffness and damping on the system. Theoretically, the greater the reducer's output torque, the greater its stiffness and damping, which allows the system to increase gain and achieve a higher bandwidth. Therefore, the greater the output torque, the greater K... PC It will also get bigger.

[0147] In the above embodiments, by constructing the flexible joint system with the same load state at the end and the joint axis of the flexible joint system in different force postures, the fourth mapping relationship between the output torque and the torque compensation gain is mainly affected by the force posture, eliminating other interference factors and accurately focusing on the effect of torque on the dynamic characteristics of the system.

[0148] In one exemplary embodiment, obtaining the basic proportional gain of the position loop in a flexible joint system includes:

[0149] When the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is in an unloaded state, the frequency of the flexible joint system is swept to obtain the basic proportional gain that maximizes the third bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0150] Specifically, the basic proportional gain is actually the basic gain of the position loop when the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is in an unloaded state. However, in the actual control process, the flexible joint system is also subject to the scheduling of the load rotational inertia and the joint output torque (indirectly reflected through steady-state current). Therefore, it is necessary to adjust the basic proportional gain by using the target load compensation gain matched with the current load rotational inertia and the target torque compensation gain matched with the current output torque.

[0151] Furthermore, when the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is in an unloaded state, the basic proportional gain is determined by performing a frequency sweep test on the flexible joint system. The basic proportional gain is the basic proportional gain that maximizes the third bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0152] The frequency sweep test process in this embodiment includes:

[0153] (1) When the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is in an unloaded state, apply a frequency sweep command.

[0154] (2) Observe or measure the closed-loop frequency response in the amplitude-frequency characteristic curve of the system.

[0155] (3) Iteratively adjust the proportional gain. The adjustment of the proportional gain will affect the bandwidth and resonant peak of the amplitude-frequency response curve. It is necessary to iteratively find the balance point until the bandwidth reaches the maximum. At the same time, ensure that the resonant peak on the amplitude-frequency response curve is precisely constrained within the preset amplitude range, that is, the predetermined range of 0-0.5dB.

[0156] (4) The base proportional gain that satisfies the constraints in (3) is taken as the optimal gain under the current load condition, i.e., the base proportional gain.

[0157] In the above embodiments, by setting the working condition of the flexible joint system to a state where the joint axis is in an unloaded posture and the end is in an unloaded state, the basic proportional gain at this time can be accurately detected. Furthermore, the basic proportional gain at this time is the gain with the maximum bandwidth and the resonant peak of the preset amplitude-frequency characteristic curve within the preset amplitude range, which makes the flexible joint system respond to control commands faster.

[0158] In one exemplary embodiment, this application discloses a control method for a robot flexible joint system, specifically controlling the position loop in the flexible joint system. The aim is to adjust the controller gain in real time so that the closed-loop system can achieve the maximum stable bandwidth under different load moments of inertia and output torques, and to constrain the closed-loop resonance peak within a predetermined optimal dynamic margin range (e.g., 0dB~0.5dB).

[0159] 1. Dispatch Gain: This scheme mainly targets the position loop proportional gain P in the flexible joint control system. P Perform scheduling.

[0160] 2. Scheduling variables: including load moment of inertia J L And the joint output torque (indirectly reflected through steady-state current I).

[0161] 3. Gain Calculation Model: The proportional gain P of the position loop after scheduling P It is a basic gain P P1 The product of the two independent compensated gains: .

[0162] Where: P P1 K: The basic proportional gain of the position loop when the joint axis of the flexible joint system is in a stress-free position and the end of the flexible joint system is unloaded. PL : Load compensation gain, reflecting the load's moment of inertia J L The effect on gain. K PC Torque compensation gain reflects the effect of joint output torque (real-time current I) on the gain.

[0163] 4. Load compensation gain K PL Determination of K: PL Used to compensate for the rotational inertia of the load J L The effect of changes on the system's resonant frequency.

[0164] 4.1 Determination of Basic Proportional Gain: With the joint axis of the flexible joint system in a stress-free position and the end effector of the flexible joint system in an unloaded state, the basic proportional gain P is determined through frequency sweep testing. P1 This makes the closed-loop resonant peak value less than 0.5dB. At this time, the standard no-load compensation gain K corresponding to the no-load state... PL1 It is defined as 1.

[0165] 4.2 Data Acquisition: Under the premise of constant stiffness (i.e., the robot's second joint axis is in a stress-free posture), position closed-loop frequency sweep tests were performed on different end-effector loads (e.g., 0 kg to 8 kg). The test results show that, at the same gain, the larger the load, the lower the resonant frequency of the system and the higher the resonant peak value.

[0166] 4.3 Load Compensation Gain Model: Through no-load (standard no-load moment of inertia J) L1 The corresponding standard no-load compensation gain K PL1 = 1) and full load (standard full load moment of inertia J) L2 The corresponding standard full-load compensation gain K PL2 Closed-loop tuning under operating conditions determines the two boundary compensation gains K. PL1 With K PL2 For any load, the moment of inertia J L Load compensation gain K PL By J L Its boundary values ​​are analytically determined, at which point the calculation formula only relates to the moment of inertia J. L It is related to the stiffness Ks, but not to the stiffness Ks.

[0167] K PL With load rotational inertia J L The following relationship must be satisfied:

[0168]

[0169] Among them, the lower limit of the inertia range (standard no-load rotational inertia) J L1 =27.730078 kg·m 2 Standard no-load compensation gain K PL1 = 1, Upper limit of inertia range (standard no-load rotational inertia) J L2 = 45.476912 kg·m 2 Standard full-load compensation gain K PL2 = 0.75.

[0170] 5. Torque compensation gain K PC Determination of K: PC This is used to compensate for the effect of changes in joint output torque (steady-state current I) on the stiffness of the reducer. Specifically, under the same load moment of inertia, as the output torque (steady-state current I) increases, the system stiffness, resonant frequency, and damping all increase.

[0171] 5.1 Data Acquisition: Under the condition that the end of the flexible joint system is fully loaded (e.g., 8 kg) and the joint axis of the flexible joint system is in different stress postures (e.g., the second joint axis is in a posture from 0° to 90°), its steady-state current I is tested and a position closed-loop frequency sweep is performed.

[0172] 5.2 Torque Compensation Gain Model: For each steady-state current I, an optimal position loop gain P is determined by manual tuning. p This ensures that the resonant peak value meets the tuning principle (e.g., less than 0.5dB). This optimal gain is related to the fundamental gain P. P1 K under current loadPL The ratio of the products is K. PC .

[0173] 5.3 The relationship between I and K PC The correspondence h(I) is a monotonically increasing function, which can be fitted using a nonlinear function or a linear interpolation lookup table method. K also needs to be considered. PC Saturation limit.

[0174]

[0175] 6. Real-time implementation of dynamic gain scheduling:

[0176] During robot operation, the controller acquires or estimates the current load moment of inertia and real-time current (representing torque) in real time, and then determines the load moment of inertia and current (representing torque) based on a pre-defined K. PL Mapping function and K PC The fitting function is used to calculate the optimal position loop proportional gain under the current working condition in real time, and then the flexible joint system is controlled based on the optimal position loop proportional gain.

[0177] This flexible joint system control scheme achieves the following technical effects through the aforementioned technical means:

[0178] 1. Achieved maximum stable bandwidth: This method uses the closed-loop resonant peak value constrained within the optimal dynamic margin range (e.g., <0.5dB) as the gold standard for gain tuning. This means that under different operating conditions, the system can always be pushed to the maximum stable gain and maximum stable bandwidth, overcoming the technical problem of conservative bandwidth in existing technologies.

[0179] 2. Adaptive to changes in load inertia: This is achieved by introducing a load compensation gain K. PL (with load rotational inertia J) L (correlation) This method can effectively compensate for the impact of load rotational inertia changes on the system's resonant frequency and stability, ensuring that the system maintains stable high dynamic performance throughout the entire range from no-load to full-load.

[0180] 3. Compensation for nonlinear stiffness of the reducer: This is achieved by introducing a torque compensation gain K. PC (Related to the output torque I), indirectly compensating for the reducer stiffness (K) S The nonlinear variation of the output torque eliminates performance fluctuations caused by stiffness changes, further enhancing the robustness and consistency of the system.

[0181] 4. The gain calculation model is accurate and efficient: It decouples the complex two-dimensional scheduling problem into two independent one-dimensional compensation gains K. PL and K PCThe product model simplifies the complexity of online computation and facilitates efficient implementation in real-time control systems.

[0182] 5. Scalability: The position loop proportional gain control method of this application is not limited to scheduling the proportional gain of the position loop, but can also be applied to the gain parameters of the velocity loop gain or other state feedback controllers.

[0183] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0184] Based on the same inventive concept, this application also provides a flexible joint system control device for implementing the flexible joint system control method described above. The solution provided by this device is similar to the solution described in the above method; therefore, the specific limitations in one or more embodiments of the flexible joint system control device provided below can be found in the limitations of the flexible joint system control method described above, and will not be repeated here.

[0185] In one exemplary embodiment, such as Figure 6 As shown, a flexible joint system control device is provided, comprising: an acquisition module 200, a query module 400, and a control module 600, wherein:

[0186] The acquisition module 200 is used to acquire the basic proportional gain of the position loop in the flexible joint system, as well as the current load moment of inertia and current output torque of the flexible joint system.

[0187] The query module 400 is used to query the target load compensation gain matching the current load rotational inertia and the target torque compensation gain matching the current output torque; wherein, the target load compensation gain and the target torque compensation gain are both control increases that maximize the bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensure that the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0188] The control module 600 is used to control the flexible joint system based on the target load compensation gain, the target torque compensation gain, and the basic proportional gain.

[0189] In one embodiment, the flexible joint system control device further includes a second mapping relationship detection module. This module is used to perform a frequency sweep on the flexible joint system for each load state when the joint axis of the flexible joint system is in a stress-free posture and the end effector of the flexible joint system is under different load states. This results in a standard load compensation gain and a standard load moment of inertia that maximizes the first bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and ensures that the resonant peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range. Based on the standard load compensation gain and standard load moment of inertia corresponding to multiple load states, a first mapping relationship between the load moment of inertia and the load compensation gain is detected. The query module 400 is further used to query the target load compensation gain matching the current load moment of inertia from the first mapping relationship.

[0190] In one embodiment, the standard load compensation gain corresponding to the multiple load states includes at least the standard no-load compensation gain corresponding to the no-load state and the standard full-load compensation gain corresponding to the full-load state, and the standard load rotational inertia corresponding to the multiple load states includes at least the standard no-load rotational inertia corresponding to the no-load state and the standard full-load rotational inertia corresponding to the full-load state; the first mapping relationship detection module is further used to detect the first mapping relationship between the load rotational inertia and the load compensation gain based on the no-load compensation gain, the no-load rotational inertia, the full-load compensation gain, and the full-load rotational inertia.

[0191] In one embodiment, the first mapping relationship detection module is further configured to: obtain the no-load resonant frequency corresponding to the preset amplitude-frequency characteristic curve when the joint axis is in a stress-free posture and the end is in an unloaded state; and obtain the full-load resonant frequency corresponding to the preset amplitude-frequency characteristic curve when the joint axis is in a stress-free posture and the end is in a fully loaded state; detect a second mapping relationship between the load compensation gain and the load resonant frequency based on the full-load compensation gain, the no-load compensation gain, the no-load resonant frequency, and the full-load resonant frequency; obtain a third mapping relationship between the preset load resonant frequency and the load rotational inertia; and detect a first mapping relationship between the load rotational inertia and the load compensation gain based on the second mapping relationship, the third mapping relationship, the no-load rotational inertia, and the no-load rotational inertia.

[0192] In one embodiment, the flexible joint system control device further includes a fourth mapping relationship determination module. This module is used to, under the condition that the load state at the end of the flexible joint system is the same and the joint axis of the flexible joint system is in different force-bearing postures, detect the standard output torque of the flexible joint system for each force-bearing posture, and perform frequency sweeping on the flexible joint system to obtain a standard torque compensation gain that maximizes the second bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and that the resonant peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range. Based on the standard output torque and standard torque compensation gain corresponding to each force-bearing posture, a fourth mapping relationship between the output torque and the torque compensation gain is obtained. The query module 400 is also used to query the target torque compensation gain that matches the current output torque from the fourth mapping relationship.

[0193] In one embodiment, the acquisition module 200 is used to perform frequency sweeping on the flexible joint system when the joint axis of the flexible joint system is in a stress-free posture and the end of the flexible joint system is in an unloaded state, to obtain the basic proportional gain that maximizes the third bandwidth corresponding to the preset amplitude-frequency characteristic curve of the flexible joint system and the resonant peak value of the preset amplitude-frequency characteristic curve is within the preset amplitude range.

[0194] Each module in the aforementioned flexible joint system control device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the operations corresponding to each module.

[0195] In one exemplary embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be as follows: Figure 7As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operating system and computer programs stored in the non-volatile storage media. The database stores data such as a second mapping relationship between load compensation gain and load resonant frequency, and a fourth mapping relationship between output torque and torque compensation gain. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a flexible joint system control method.

[0196] Those skilled in the art will understand that Figure 7 The structure shown is a block diagram of a partial structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0197] In one embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0198] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0199] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0200] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0201] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0202] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A flexible joint system control method characterized by, The method comprises: obtaining a basic proportional gain of a position loop in a flexible joint system, and a current load moment of inertia and a current output torque of the flexible joint system; querying a target load compensation gain matched with the current load moment of inertia, and a target torque compensation gain matched with the current output torque; wherein the target load compensation gain and the target torque compensation gain are control gains that make a preset amplitude-frequency characteristic curve of the flexible joint system correspond to a maximum bandwidth, and a resonance peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range; controlling the flexible joint system according to the target load compensation gain, the target torque compensation gain and the basic proportional gain.

2. The method of claim 1, wherein, Before the querying the target load compensation gain matched with the current load moment of inertia, the method further comprises: in a case that a joint shaft of the flexible joint system is in a force-free posture and an end of the flexible joint system is in different load states, for each of the load states, sweeping frequency of the flexible joint system to obtain a standard load compensation gain and a standard load moment of inertia in a case that a first bandwidth corresponding to a preset amplitude-frequency characteristic curve of the flexible joint system is maximum, and a resonance peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range; detecting a first mapping relationship between load moments of inertia and load compensation gains according to the standard load compensation gains and the standard load moments of inertia corresponding to the load states respectively; the querying the target load compensation gain matched with the current load moment of inertia comprises: querying the target load compensation gain matched with the current load moment of inertia from the first mapping relationship.

3. The method of claim 2, wherein, The standard load compensation gains corresponding to the load states respectively at least include a standard empty load compensation gain corresponding to an empty load state and a standard full load compensation gain corresponding to a full load state, and the standard load moments of inertia corresponding to the load states respectively at least include a standard empty load moment of inertia corresponding to the empty load state and a standard full load moment of inertia corresponding to the full load state; the detecting the first mapping relationship between load moments of inertia and load compensation gains according to the standard load compensation gains and the standard load moments of inertia corresponding to the load states respectively comprises: detecting the first mapping relationship between load moments of inertia and load compensation gains according to the empty load compensation gain, the empty load moment of inertia, the full load compensation gain and the full load moment of inertia.

4. The method of claim 3, wherein, the detecting the first mapping relationship between load moments of inertia and load compensation gains according to the empty load compensation gain, the empty load moment of inertia, the full load compensation gain and the full load moment of inertia comprises: obtaining an empty load resonance frequency corresponding to the preset amplitude-frequency characteristic curve in a case that the joint shaft is in the force-free posture and the end is in the empty load state, and obtaining a full load resonance frequency corresponding to the preset amplitude-frequency characteristic curve in a case that the joint shaft is in the force-free posture and the end is in the full load state; According to the full-load compensation gain, the no-load compensation gain, the no-load resonant frequency and the full-load resonant frequency, a second mapping relationship between a load compensation gain and a load resonant frequency is detected; A third mapping relationship between a preset load resonant frequency and a load moment of inertia is obtained; According to the second mapping relationship, the third mapping relationship, the no-load moment of inertia and the no-load moment of inertia, a first mapping relationship between a load moment of inertia and a load compensation gain is detected.

5. The method of claim 1, wherein, Before the target torque compensation gain matching the current output torque is queried, the method further comprises: In the case that the load state of the end of the flexible joint system is the same, and the joint shaft of the flexible joint system is in different force states, for each force state, a standard output torque of the flexible joint system is detected, and the flexible joint system is swept to obtain a standard torque compensation gain, so that a preset amplitude-frequency characteristic curve of the flexible joint system corresponds to a second bandwidth which is maximum, and a resonance peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range; According to the standard output torque and the standard torque compensation gain corresponding to each force state respectively, a fourth mapping relationship between an output torque and a torque compensation gain is obtained; The target torque compensation gain matching the current output torque is queried, comprising: The target torque compensation gain matching the current output torque is queried from the fourth mapping relationship.

6. The method of claim 1, wherein, The basic proportional gain of the position loop in the flexible joint system is obtained, comprising: In the case that the joint shaft of the flexible joint system is in a force-free state, and the end of the flexible joint system is in a no-load state, the flexible joint system is swept to obtain a basic proportional gain in the case that a preset amplitude-frequency characteristic curve of the flexible joint system corresponds to a third bandwidth which is maximum, and a resonance peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range.

7. A flexible joint system control device characterized by comprising: The device comprises: An acquisition module is configured to acquire a basic proportional gain of a position loop in a flexible joint system, and a current load moment of inertia and a current output torque of the flexible joint system; A query module is configured to query a target load compensation gain matching the current load moment of inertia, and a target torque compensation gain matching the current output torque; wherein the target load compensation gain and the target torque compensation gain are both control gains, so that a preset amplitude-frequency characteristic curve of the flexible joint system corresponds to a bandwidth which is maximum, and a resonance peak value of the preset amplitude-frequency characteristic curve is within a preset amplitude range; A control module is configured to control the flexible joint system according to the target load compensation gain, the target torque compensation gain and the basic proportional gain.

8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The processor executes the computer program to implement the steps of the method in any one of claims 1 to 6.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

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