Mechanical arm joint speed limiting method and device
By using the prediction and weighted damped pseudo-inverse method, potential over-limit joints are identified in advance and the weights are adjusted, which solves the response lag and trajectory smoothness problems in the robot arm joint speed limit, achieves more robust trajectory tracking control, and improves the stability and consistency of the robot arm.
Patent Information
- Application Number
- CN202510866726.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-26
- Publication Date
- 2025-09-23
AI Technical Summary
The existing methods for limiting the joint speed of robotic arms have problems such as response lag, poor trajectory smoothness, and difficulty in avoiding extreme risks in a timely manner. In particular, they are prone to joint speed peaks and trajectory oscillations near singular configurations.
By obtaining the target Cartesian velocity and joint angle vector of the end of the robotic arm, predicting the joint velocity vectors of the current and next cycles, identifying the potential out-of-limit joints, and adjusting the joint weighting matrix to increase the weight of the potential out-of-limit joints, the weighted damped pseudo-inverse method is used to solve the initial joint velocity vector instruction to achieve active control and smooth adjustment.
The advance prediction and adaptive weighting methods are integrated into the velocity solution process to avoid exceeding the joint velocity limit, improve trajectory consistency and stability, ensure smooth and stable trajectory tracking, and improve tracking performance.
Smart Images
Figure CN120680508A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of robotic arms, and in particular to a method and device for limiting the joint speed of a robotic arm. Background Art
[0002] During the movement of the robotic arm, it is necessary to ensure the accuracy of the end movement and control the joint speed to ensure that physical constraints are met.
[0003] In related technologies, the velocities of each joint of a robotic arm are calculated using a pseudo-inverse method. When certain joint velocities are found to exceed the limit, the exceeding velocity components are saturated and clipped or scaled proportionally to bring the exceeding joint velocities back to a feasible range. However, by this time, the corresponding joint velocities may have already experienced significant deviations and sudden changes. Furthermore, the subsequent processing of joint velocities can also easily cause sudden changes in joint velocities, disrupting the continuity and smoothness of the trajectory. Especially near singular configurations, the pseudo-inverse method often produces extremely large joint velocity peaks, which are then clipped, making the execution trajectory more susceptible to oscillation or fluctuation. Furthermore, the uniform scaling method after detecting an over-limit makes it difficult to avoid extreme risks in a timely manner, often sacrificing tracking accuracy to maintain safety. Summary of the Invention
[0004] The purpose of the present invention is to provide a method and device for limiting the speed of a robotic arm joint, so as to alleviate the technical problems of the conventional method for limiting the speed of a robotic arm joint, such as response lag, limited support for trajectory smoothness, and difficulty in avoiding extreme risks in a timely manner.
[0005] The present invention provides a method for limiting the speed of a robotic arm joint, which includes:
[0006] Get the target Cartesian velocity of the end of the robot arm and the joint angle vector of the current cycle;
[0007] Predict the joint velocity vector of the current cycle and the joint velocity vector of the next cycle;
[0008] Determine whether there are potential over-limit joints;
[0009] If so, adjusting the joint weighting matrix so that the weight of the potential over-limit joint is greater than the weights of other joints of the robotic arm;
[0010] Solve for the initial joint velocity vector commands.
[0011] Preferably, as an implementable embodiment, after solving the initial joint velocity vector instruction, the method further includes:
[0012] Determining whether there is an over-limit joint in the initial joint velocity vector instruction;
[0013] If not, the initial joint velocity vector instruction is used as the final joint velocity vector instruction;
[0014] If so, scaling the initial joint velocity vector instruction with a scaling factor between 0 and 1, and using the scaled joint velocity vector instruction as the final joint velocity vector instruction;
[0015] The final joint velocity vector instruction is output to control each joint driver of the robotic arm.
[0016] Preferably, as an implementable method, the method for predicting the joint velocity vector of the current cycle includes:
[0017] According to the joint angle vector θ of the current cycle k , calculate the Jacobian matrix J of the current cycle k , the calculation formula is: Among them, k is the current cycle number, J k The first three rows correspond to the relationship between the linear velocity of the end of the manipulator and the joint velocity vector of the current cycle, and the last three rows correspond to the relationship between the angular velocity of the end of the manipulator and the joint velocity vector of the current cycle;
[0018] According to the target Cartesian velocity v d and the Jacobian matrix J of the current cycle k , use damped least squares pseudo-inverse to estimate the joint velocity vector of the current cycle The calculation formula is: in,
[0019] Preferably, as an implementable method, the method for predicting the joint velocity vector of the next cycle includes:
[0020] According to the joint velocity vector of the current cycle Calculate the joint angle vector θ for the next cycle k+1,pred , the calculation formula is: Wherein, Δt is the sampling period;
[0021] According to the joint angle vector θ of the next cycle k+1,pred , calculate the Jacobian matrix J of the next cycle k+1,pred , the calculation formula is: J k+1,pred =J(θ k+1,pred );
[0022] According to the target Cartesian velocity v d and the Jacobian matrix J of the next cycle k+1,pred , calculate the joint velocity vector of the next cycle The calculation formula is: in,
[0023] Preferably, as an implementable method, the determining whether there is a potential out-of-limit joint includes:
[0024] Compare the joint speed of the current cycle and the joint speed of the next cycle with the limit speed of the corresponding joint Compare and get the set of potential over-limit joints:
[0025]
[0026] Where i is the joint number of the robot arm, ∈ p ∈(0,1) is the prediction threshold.
[0027] Preferably, as an implementable method, the joint weight matrix is: W k =diag(w 1,k ,w 2,k ,…,w n,k );
[0028] The weight of the joint numbered i of the robotic arm is:
[0029] is the weight adjustment factor.
[0030] Preferably, as an implementable method, the method for solving the initial joint velocity vector instruction includes:
[0031] According to the Jacobian matrix J of the current cycle k , the target Cartesian velocity v d And the joint weight matrix W k , solve the initial joint velocity vector instruction The calculation formula is: Wherein, the damping factor λ>0;
[0032] The initial joint velocity vector command The analytical solution is:
[0033] in,
[0034] Preferably, as an implementable method, the determining whether there is an over-limit joint in the initial joint velocity vector instruction includes:
[0035] The joint speed in the initial joint speed vector instruction is compared with the limit speed of the corresponding joint By comparison, we get the set of the over-limit joints:
[0036] Preferably, as an implementable method, the calculation formula of the scaling factor is:
[0037]
[0038] The mechanical arm joint speed limiting device provided by the present invention comprises:
[0039] The acquisition module is used to obtain the target Cartesian velocity of the end of the robot arm and the joint angle vector of the current cycle;
[0040] Prediction module, used to predict the joint velocity vector of the current cycle and the joint velocity vector of the next cycle;
[0041] a judgment module, configured to judge whether there is a potential out-of-limit joint, and if so, adjust the joint weighting matrix so that the weight of the potential out-of-limit joint is greater than the weights of other joints of the robotic arm;
[0042] The solving module is used to solve the initial joint velocity vector instructions.
[0043] Compared with the prior art, the present invention has the following beneficial effects:
[0044] The robotic arm joint speed limiting method and device provided by this invention can provide an early warning before joint speed reaches its limit, allowing time for weight adjustment and planning, fundamentally avoiding the passive lag of traditional methods. By incorporating joint limit factors into the speed solution through advance prediction and adaptive weighting, this method achieves global consideration and active control of the speed of each robotic arm joint, ensuring smooth and stable trajectory tracking while strictly ensuring that it does not exceed the limit. This makes tracking control more proactive and robust, improves trajectory consistency and stability, and significantly improves tracking performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.
[0046] Figure 1 is a schematic flow chart of a method for limiting the joint speed of a robotic arm in the related art;
[0047] Figure 2 A first schematic flow chart of a method for limiting the joint speed of a robotic arm provided by an embodiment of the present invention;
[0048] Figure 3A second schematic flow chart of the method for limiting the joint speed of a robotic arm provided by an embodiment of the present invention;
[0049] Figure 4 A schematic diagram of the structure of a method for limiting the joint speed of a robotic arm provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0050] In related technologies, methods for limiting the speed of robotic arm joints are as follows: Figure 1 As shown in the figure, after the desired Cartesian velocity command is given at the end of the manipulator, the Jacobian matrix J of the current manipulator is first calculated; then the pseudo-inverse (or weighted damping pseudo-inverse) of the Jacobian matrix J is obtained. + ; Then multiply the terminal velocity by the pseudo-inverse to get the initial joint velocity solution (This corresponds to the minimum norm solution of the redundant manipulator solution); finally, the calculated joint velocity components are compared with the joint velocity limits one by one. When the speed of some joints exceeds the limit, the speed components exceeding the limit are saturated and limited or scaled proportionally as a whole.
[0051] The above method has the following shortcomings:
[0052] 1. Passive response and lack of prediction: This method has no predictive mechanism and can only respond passively to joint limit violations. Scaling is only performed when the calculated velocity at a particular step exceeds the joint limit, at which point the joint velocity may have already deviated significantly or experienced sudden changes.
[0053] 2. Poor trajectory consistency: Because scaling is a post-process, it can cause sudden changes in joint velocity, disrupting the continuity and smoothness of the trajectory. Especially near singular configurations, the pseudo-inverse algorithm often produces extremely large joint velocity peaks, which are then clipped, causing oscillation or fluctuation in the execution trajectory.
[0054] 3. Lack of timely avoidance capabilities: Traditional methods cannot identify which joints are approaching their limits in advance, making it impossible to adjust control strategies in advance. Instead, they can only uniformly scale after detecting an over-limit. This approach makes it difficult to avoid extreme risks in a timely manner, often sacrificing tracking accuracy to maintain safety.
[0055] Based on this, the present invention provides a method for limiting the speed of a robotic arm joint, which introduces multi-step prediction and dynamic weighting on the basis of the pseudo-inverse method, and achieves smooth speed adjustment by identifying potential over-limit joints in advance and weakening their influence.
[0056] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.
[0057] The present invention will be further described in detail below through specific implementation examples in conjunction with the accompanying drawings.
[0058] Figure 2 A schematic flow chart of a method for limiting the speed of a robotic arm joint provided by one embodiment of the present invention, the method comprising:
[0059] S102, obtaining the target Cartesian velocity of the end of the manipulator and the joint angle vector of the current cycle; wherein the target Cartesian velocity v of the end of the manipulator is d To pre-enter parameters as needed: The joint angle vector θ of the current cycle k It can be obtained through real-time acquisition. Assume that the robot arm has n rotational joints and define the number of the current control cycle as k. At this time, the joint angle vector of the current cycle is:
[0060] S104, predicting the joint velocity vector of the current cycle and the joint velocity vector of the next cycle;
[0061] Specifically, based on the target Cartesian velocity of the manipulator end and the joint angle vectors of the current cycle obtained in the previous step, the joint velocity vectors for the current cycle and the next cycle are predicted. This gives the controller a forward-looking capability, enabling it to predict the future velocity trends of each joint and identify joints that may exceed their limits. This mechanism provides early warning before joint speed limits are reached, allowing time for weight adjustment and planning, fundamentally avoiding the passive lag of traditional methods.
[0062] S106, determining whether there is a potential over-limit joint;
[0063] Specifically, the joint velocity vector of the current cycle and the joint velocity vector of the next cycle predicted in the previous step can be compared with the limit velocity of the corresponding joint to determine whether there is a potential over-limit joint.
[0064] S108, if yes, adjust the joint weight matrix so that the weight of the potential over-limit joint is greater than the weights of other joints of the robotic arm;
[0065] According to the prediction results, the joint weighting matrix is constructed and adjusted in real time, and the weight of the joint predicted to be out of limit is appropriately increased, thereby automatically reducing the joint velocity output during the weighted pseudo-inverse solution, reducing its contribution in the subsequent inverse solution, playing the role of "weakening the dangerous joint", and making the pseudo-inverse solution automatically biased towards a safe direction, avoiding the large peaks generated by the pseudo-inverse solution, and ensuring that the joint velocity curve is smoother and more continuous.
[0066] S110, solving the initial joint velocity vector instruction.
[0067] Specifically, according to the adjusted joint weighted matrix above, the initial joint velocity vector instruction is solved and used to control the joint drivers of the robot arm. In most cases, the joint velocity limit can be guaranteed, and the impact of the joint velocity limit on the trajectory accuracy of the robot arm can be limited.
[0068] In summary, the robot arm joint speed limiting method provided in this embodiment incorporates the joint limit factor into the speed solution process through advance prediction and adaptive weighting, thereby realizing global consideration and active control of the speed of each joint of the robot arm, so that the trajectory tracking satisfies both smoothness and stability while ensuring that it strictly does not exceed the limit. Therefore, the tracking control is more active and robust, the trajectory consistency and stability are improved, and the tracking performance is significantly improved.
[0069] After step S110, the method provided in this embodiment further includes: determining whether there is an over-limit joint in the initial joint velocity vector instruction; if not, using the initial joint velocity vector instruction as the final joint velocity vector instruction; if so, scaling the initial joint velocity vector instruction with a scaling factor between 0 and 1, and using the scaled joint velocity vector instruction as the final joint velocity vector instruction; outputting the final joint velocity vector instruction to control the joint drivers of the manipulator. This step can be used as a final protection measure. If the speed of some joints still exceeds the limit speed, all joint speeds are uniformly scaled proportionally to ensure that the motion complies with the speed constraint. This global scaling serves as the final protection mechanism to ensure that physical limitations are not violated under any circumstances, while minimizing the distortion of the trajectory. Even in extreme or singular situations, the speed can be adjusted more smoothly and promptly, taking into account both real-time performance and constraint satisfaction. It should be noted that since the above steps S108 to S110 have already performed weighted processing on the potential out-of-limit joints, the situation and degree of uniform scaling that is ultimately required are very rare. Even if scaling is required, the amplitude is small, and the impact on the end trajectory accuracy is smaller than that of traditional methods. In addition, under extreme conditions, simple proportional scaling can satisfy the constraints, without the need to use complex optimization methods such as quadratic programming (QP), and there is no need to optimize performance to satisfy the constraints.
[0070] Specifically, the prediction method of the joint velocity vector of the current cycle includes:
[0071] A1, according to the joint angle vector θ of the current cycle k , calculate the Jacobian matrix J of the current cycle k , the calculation formula is: Among them, k is the current cycle number, J k The first three rows correspond to the relationship between the linear velocity of the end of the robot and the joint velocity vector of the current cycle, and the last three rows correspond to the relationship between the angular velocity of the end of the robot and the joint velocity vector of the current cycle.
[0072] A2, according to the target Cartesian velocity v d and the Jacobian matrix J of the current cycle k , use damped least squares pseudo-inverse to estimate the joint velocity vector of the current cycle The calculation formula is: in, This is the damped least squares pseudo-inverse of the Jacobian matrix of the current period.
[0073] Specifically, the prediction method of the joint velocity vector of the next cycle includes:
[0074] B1, according to the joint velocity vector of the current cycle Calculate the joint angle vector θ for the next cycle k+1,pred , the calculation formula is: Where Δt is the sampling period.
[0075] B2, according to the joint angle vector θ of the next cycle k+1,pred , calculate the Jacobian matrix J of the next cycle k+1,pred , the calculation formula is: J k+1,pred =J(θ k+1,pred ).
[0076] B3, according to the target Cartesian velocity v d and the Jacobian matrix J of the next cycle k+1,pred , calculate the joint velocity vector of the next cycle The calculation formula is: in, J k+1,pred + This is the damped least squares pseudo-inverse of the Jacobian matrix of the next period.
[0077] The above step of determining whether there is a potential over-limit joint may include: comparing the joint speed of the current cycle and the joint speed of the next cycle with the limit speed of the corresponding joint. Compare and get the set of potential over-limit joints: Where i is the joint number of the robot arm, i = 1, ..., n; ∈ p ∈(0,1) is the prediction threshold. p The possible value is 0.9.
[0078] The joint weight matrix is: W k =diag(w 1,k ,w 2,k ,…,w n,k ); where the weight of the joint numbered i of the robot arm is: is the weight adjustment factor. w The possible value is 0.5.
[0079] The solution method of the initial joint velocity vector instruction includes: according to the Jacobian matrix J of the current cycle k 、Target Cartesian velocity v d and the joint weight matrix W k , solve the initial joint velocity vector command The calculation formula is: Here, the damping factor λ>0.
[0080] Initial joint velocity vector command The analytical solution is: in,
[0081]
[0082] in, Considered as the initial joint velocity vector for this cycle.
[0083] The above step of determining whether there is an over-limit joint in the initial joint velocity vector instruction may specifically include: comparing the joint velocity in the initial joint velocity vector instruction with the limit velocity of the corresponding joint. Compare and get the set of over-limit joints:
[0084] The calculation formula for the scaling factor when scaling the velocity of the over-limit joint is:
[0085]
[0086] like Then order like Then order At this time, it can be guaranteed that for any i∈{1,…,n},
[0087] Figure 3 A method for limiting the speed of a robotic arm joint provided by one embodiment of the present invention includes:
[0088] Target Cartesian velocity input;
[0089] Calculate the Jacobian matrix J k ;
[0090] Multi-step prediction of joint velocity trends;
[0091] Mark potential overrun joints;
[0092] Dynamically adjust the joint weight matrix W k ;
[0093] Weighted damping pseudo-inverse solution for initial joint velocity
[0094] Determine whether the speed is still exceeding the limit;
[0095] If so, scale all joint velocities uniformly
[0096] If not, keep the current joint speed
[0097] Output joint speed command.
[0098] Figure 4 A mechanical arm joint speed limiting device provided in one embodiment of the present invention includes:
[0099] An acquisition module 10 is used to obtain the target Cartesian velocity of the end of the robotic arm and the joint angle vector of the current cycle;
[0100] Prediction module 20, used to predict the joint velocity vector of the current cycle and the joint velocity vector of the next cycle;
[0101] A determination module 30 is configured to determine whether there is a potential out-of-limit joint, and if so, adjust the joint weighting matrix so that the weight of the potential out-of-limit joint is greater than the weights of other joints of the robotic arm;
[0102] The solving module 40 is used to solve the initial joint velocity vector instruction.
[0103] The robotic arm joint speed limiting device provided in this embodiment has the same technical features as the above-mentioned robotic arm joint speed limiting method, and therefore can also solve the same technical problems and achieve the same technical effects.
[0104] The above-mentioned judgment module can also be used to determine whether there is an out-of-limit joint in the initial joint velocity vector instruction; if the judgment result is no, the initial joint velocity vector instruction is used as the final joint velocity vector instruction; if the judgment structure is yes, the initial joint velocity vector instruction is scaled, and the scaling coefficient is between 0 and 1, and the scaled joint velocity vector instruction is used as the final joint velocity vector instruction.
[0105] The robotic arm joint speed limiting device provided in this embodiment may further include a control module for outputting a final joint speed vector instruction to control each joint driver of the robotic arm.
[0106] This embodiment also provides a machine-readable storage medium, which stores machine-executable instructions. When the machine-executable instructions are called and executed by a processor, the machine-executable instructions prompt the processor to implement the above-mentioned method for limiting the speed of the robotic arm joint.
[0107] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described equipment and devices can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.
[0108] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.
[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for limiting the speed of a robot arm joint, characterized in that: include: Get the target Cartesian velocity of the end of the robot arm and the joint angle vector of the current cycle; Predict the joint velocity vector of the current cycle and the joint velocity vector of the next cycle; Determine whether there are potential over-limit joints; If so, adjusting the joint weighting matrix so that the weight of the potential over-limit joint is greater than the weights of other joints of the robotic arm; Solve for the initial joint velocity vector commands.
2. The method for limiting the speed of a robotic arm joint according to claim 1, wherein: After solving the initial joint velocity vector instruction, the method further includes: Determining whether there is an over-limit joint in the initial joint velocity vector instruction; If not, the initial joint velocity vector instruction is used as the final joint velocity vector instruction; If so, scaling the initial joint velocity vector instruction with a scaling factor between 0 and 1, and using the scaled joint velocity vector instruction as the final joint velocity vector instruction; The final joint velocity vector instruction is output to control each joint driver of the robotic arm.
3. The method for limiting the speed of a robot arm joint according to claim 1 or 2, characterized in that: The method for predicting the joint velocity vector of the current cycle includes: According to the joint angle vector θ of the current cycle k , calculate the Jacobian matrix J of the current cycle k , the calculation formula is: Among them, k is the current cycle number, J k The first three rows correspond to the relationship between the linear velocity of the end of the manipulator and the joint velocity vector of the current cycle, and the last three rows correspond to the relationship between the angular velocity of the end of the manipulator and the joint velocity vector of the current cycle; According to the target Cartesian velocity v d and the Jacobian matrix J of the current cycle k , use damped least squares pseudo-inverse to estimate the joint velocity vector of the current cycle The calculation formula is: in, 4. The method for limiting the speed of a robot arm joint according to claim 3, wherein: The method for predicting the joint velocity vector of the next cycle includes: According to the joint velocity vector of the current cycle Calculate the joint angle vector θ for the next cycle k+1,pred , the calculation formula is: Wherein, Δt is the sampling period; According to the joint angle vector θ of the next cycle k+1,pred , calculate the Jacobian matrix J of the next cycle k+1,pred , the calculation formula is: J k+1,pred =J(θ k+1,pred ); According to the target Cartesian velocity v d and the Jacobian matrix J of the next cycle k+1,pred , calculate the joint velocity vector of the next cycle The calculation formula is: in, 5. The method for limiting the speed of a robot arm joint according to claim 4, characterized in that: The determination of whether there is a potential over-limit joint includes: Compare the joint speed of the current cycle and the joint speed of the next cycle with the limit speed of the corresponding joint Compare and get the set of potential over-limit joints: Where i is the joint number of the robot arm, ∈ p ∈(0,1) is the prediction threshold.
6. The method for limiting the speed of a robot arm joint according to claim 5, characterized in that: The joint weight matrix is: W k =diag(w 1,k ,w 2,k ,…,w n,k ); The weight of the joint numbered i of the robotic arm is: δ w ∈(0,1) is the weight adjustment factor.
7. The method for limiting the speed of a robot arm joint according to claim 6, wherein: The method for solving the initial joint velocity vector instruction includes: According to the Jacobian matrix J2 of the current cycle, the target Cartesian speed v d And the joint weight matrix W k , solve the initial joint velocity vector instruction The calculation formula is: Wherein, the damping factor λ>0; The initial joint velocity vector command The analytical solution is: in, 8. The method for limiting the speed of a robot arm joint according to claim 2, wherein: The determining whether there is an over-limit joint in the initial joint velocity vector instruction includes: The joint speed in the initial joint speed vector instruction is compared with the limit speed of the corresponding joint By comparison, we get the set of the over-limit joints:
9. The method for limiting the speed of a robot arm joint according to claim 8, wherein: The calculation formula of the scaling factor is:
10. A robot arm joint speed limiting device, characterized in that: include: The acquisition module is used to obtain the target Cartesian velocity of the end of the robot arm and the joint angle vector of the current cycle; Prediction module, used to predict the joint velocity vector of the current cycle and the joint velocity vector of the next cycle; a judgment module, configured to judge whether there is a potential out-of-limit joint, and if so, adjust the joint weighting matrix so that the weight of the potential out-of-limit joint is greater than the weights of other joints of the robotic arm; The solving module is used to solve the initial joint velocity vector instructions.