Track control method and system of brushless push rod

Abstract

The invention relates to the technical field of mechanical control, in particular to a trajectory control method and system for a brushless push rod, and the method comprises the steps: generating a reference motion trajectory of the brushless push rod based on a load dynamics model of the brushless push rod; calculating a critical speed threshold value corresponding to the current load working condition according to the motor current and the external load force; comparing the reference speed curve with a critical speed threshold value, and triggering a track adjustment condition when the reference speed reaches a preset proportion of the critical speed; and after a trajectory adjustment condition is triggered, associating a critical speed threshold value with the reference speed curve to establish a dynamic speed constraint, and performing attenuation reconstruction on the reference motion trajectory based on the dynamic speed constraint to obtain a final trajectory control strategy. According to the brushless push rod, the problems of impact and unsafety caused by the fact that an existing brushless push rod still operates according to a fixed track when the load changes are effectively solved, and the control stability and the operation safety of the push rod are improved.

Description

Technical Field

[0001] This invention relates to the field of mechanical control technology, and in particular to a method and system for trajectory control of brushless push rods. Background Technology

[0002] As a type of linear drive device commonly used in home adjustment equipment, brushless linear actuators typically use brushless DC motors as a power source to achieve linear telescopic motion through a transmission mechanism. With the increasing demands for motion smoothness, accuracy, and safety in application scenarios, brushless linear actuators face several technical challenges in motion control.

[0003] Existing brushless linear actuator control methods typically use preset speed trajectories or fixed acceleration models to drive the actuator's motion. However, in actual operation, the external load on the actuator changes with operating conditions, and a fixed trajectory cannot reflect the impact of the current load on the actuator's allowable speed. Because the control system often cannot dynamically adjust the speed trajectory based on real-time load, the actuator may continue to operate along a fixed trajectory even when the load increases. This can lead to problems such as excessively high instantaneous speed, insufficient driving force, or mechanical shock when approaching the stroke limit. This issue directly affects the actuator's operational smoothness and the mechanism's safety. Summary of the Invention

[0004] This invention provides a trajectory control method for a brushless push rod, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for trajectory control of a brushless actuator, the method comprising: Based on the load dynamics model of the brushless linear actuator, a reference motion trajectory of the brushless linear actuator is generated, which includes a reference velocity curve and a reference acceleration curve. Calculate the critical speed threshold corresponding to the current load condition based on the motor current and external load force; The baseline speed curve is compared with the critical speed threshold. When the baseline speed reaches a preset ratio of the critical speed, the trajectory adjustment condition is triggered. After the trajectory adjustment condition is triggered, the critical speed threshold is associated with the reference speed curve to establish a dynamic speed constraint, and the reference motion trajectory is attenuated and reconstructed based on the dynamic speed constraint to obtain the final trajectory control strategy.

[0006] Furthermore, the trajectory adjustment condition also includes: triggering the trajectory adjustment condition when the predicted displacement of the reference motion trajectory is about to enter the safety boundary, wherein the safety boundary is determined based on the remaining distance between the current position of the push rod and the travel limit.

[0007] Furthermore, the critical speed threshold corresponding to the current load condition is calculated based on the motor current and external load force, including: Calculate the instantaneous output thrust of the brushless push rod based on the detected motor current value; Based on the external load force, determine the equivalent load of the push rod under the current working condition; Based on the mechanical balance relationship established between the instantaneous output thrust and the equivalent load, the maximum permissible speed of the push rod under the current working condition is calculated, and the maximum permissible speed is the critical speed threshold.

[0008] Furthermore, establishing dynamic speed constraints by associating the critical speed threshold with the reference speed curve includes: The critical speed threshold is updated in real time based on the real-time operating condition information of the brushless actuator. The updated critical speed threshold is used as the upper speed limit, and compared with the baseline speed curve time by time to obtain a dynamic speed limit curve based on the time series. When the reference speed curve exceeds the corresponding speed value of the dynamic speed limit curve at any moment, the corresponding speed value is taken as the target speed at that moment. A target velocity curve is constructed based on the target velocity at each time point, and the target velocity curve is used as the dynamic velocity constraint.

[0009] Further, the attenuation reconstruction includes: The reference velocity curve is subjected to amplitude limiting processing to obtain an amplitude-limited velocity sequence; A target acceleration sequence is constructed based on the limited velocity sequence, and the limited velocity sequence and the target acceleration sequence are subjected to constraint smoothing under the dynamic velocity constraint.

[0010] Furthermore, the amplitude limiting process is based on an S-shaped trajectory planning function or an exponential decay function.

[0011] Furthermore, before the attenuation reconstruction, the method further includes: determining the trajectory interval that needs to be attenuated based on the dynamic velocity constraint, wherein the trajectory interval is obtained by identifying the time period in the reference velocity curve that exceeds the dynamic velocity constraint.

[0012] Further, after completing the attenuation reconstruction, the process includes: Identify the connection boundary between the decayed trajectory and the undecayed trajectory; The velocity and acceleration at the connection boundary are continuously checked; When a discontinuity in the velocity or acceleration is detected, local smoothing correction is performed on several trajectory points at the connection boundary. Based on the correction results, a reconstructed trajectory that satisfies both velocity and acceleration continuity is generated.

[0013] A trajectory control system for a brushless linear actuator, the system comprising: The reference trajectory generation module generates a reference motion trajectory for the brushless push rod based on the load dynamics model of the brushless push rod. The reference motion trajectory includes a reference velocity curve and a reference acceleration curve. The speed threshold calculation module calculates the critical speed threshold corresponding to the current load condition based on the motor current and external load force. The trajectory adjustment trigger module compares the reference speed curve with the critical speed threshold. When the reference speed reaches a preset ratio of the critical speed, the trajectory adjustment condition is triggered. The control strategy generation module, after triggering the trajectory adjustment condition, associates the critical speed threshold with the reference speed curve to establish a dynamic speed constraint, and performs attenuation reconstruction on the reference motion trajectory based on the dynamic speed constraint to obtain the final trajectory control strategy.

[0014] Furthermore, the speed threshold calculation module includes: The instantaneous thrust calculation unit calculates the instantaneous output thrust of the brushless push rod based on the detected motor current value. The equivalent load determination unit determines the equivalent load of the push rod under the current working condition based on the external load force. The maximum speed calculation unit establishes a mechanical balance relationship between the instantaneous output thrust and the equivalent load, and calculates the maximum permissible speed of the push rod under the current working condition. The maximum permissible speed is the critical speed threshold.

[0015] The technical solution of this invention can achieve the following technical effects: It effectively solves the problem of shock and safety issues caused by existing brushless actuators running along a fixed trajectory when the load changes, and improves the smoothness of actuator control and operational safety.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the trajectory control method for a brushless linear actuator; Figure 2 A flowchart illustrating the process for calculating the critical speed threshold corresponding to the current load condition; Figure 3 A flowchart illustrating the process of establishing dynamic velocity constraints; Figure 4 A schematic diagram of the attenuation reconstruction process; Figure 5 This is a flowchart illustrating the relevant steps after attenuation reconstruction is completed. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] Example 1: like Figure 1 As shown, this application provides a trajectory control method for a brushless actuator, the method comprising: S1: Based on the load dynamics model of the brushless push rod, generate the reference motion trajectory of the brushless push rod, which includes the reference velocity curve and the reference acceleration curve; Specifically, based on the structural characteristics of the brushless linear actuator and the output performance of the brushless DC motor, a load dynamics model is established to describe the actuator's motion behavior. This model reflects the force changes, inertial response, and velocity change trends that may occur during the acceleration, constant speed, and deceleration phases of the linear actuator, thereby describing the actuator's motion capability under different load conditions. When establishing this model, the allowable acceleration range and velocity change characteristics of the linear actuator during the force application process can be determined by combining the actuator's transmission form, the structural characteristics of the internal lead screw and nut mechanism, friction characteristics, inertia influence, and the load change along the actuator's motion direction. Based on this, to generate a reference motion trajectory for the brushless actuator under normal operating conditions, the speed change process can be planned according to the target displacement range and motion time. This ensures that the actuator exhibits speed and acceleration changes that conform to dynamic laws during startup, stable motion, and approach to the target position. For example, during the actuator startup phase, the speed can be increased gradually, coupled with a moderate and controllable acceleration change, allowing the actuator to smoothly transition from a stationary state to a moving state. When the actuator reaches the middle stroke, the acceleration can be adjusted to zero or maintain minimal fluctuations, allowing it to run at a relatively stable speed. As the actuator approaches the target position, the speed is gradually reduced, and the acceleration is controlled to gradually decrease, so that the actuator can achieve a smoother braking effect before reaching the end position. By processing the above speed change process continuously, a smooth, gradual reference speed curve that conforms to the actual execution capability can be obtained. Simultaneously, based on the force conditions and actuator dynamic characteristics during the speed change process, a corresponding reference acceleration curve is generated.

[0022] S2: Calculate the critical speed threshold corresponding to the current load condition based on the motor current and external load force; Specifically, the current operating current of the motor and the external load force borne by the push rod are used to evaluate the push rod's operating capability under this condition. The motor current reflects the load changes borne by the brushless push rod during actual movement, while the external load force characterizes the reaction force experienced by the push rod in different postures or operating environments. By comprehensively analyzing the trends of these two factors, the speed range within which the push rod can maintain stable movement without causing significant impact or overload risk can be determined. In a preferred embodiment, the motor current can be continuously collected during push rod operation, combined with real-time or periodic acquisition of the external load force, to determine the push rod's operating status. For example, when the motor current approaches a certain safe proportion of its rated operating range, or when the external load force shows a significant increasing trend, it can be inferred that the upper limit of the safe speed that the push rod can achieve under this condition decreases. Based on this judgment, a critical speed threshold can be determined to limit the push rod's movement speed, reflecting the extreme speed at which the push rod can safely operate under the current load conditions. This critical speed threshold can be dynamically updated according to the load changes over time, making it closer to the push rod's operating capability in the actual working environment.

[0023] S3: Compare the baseline speed curve with the critical speed threshold. When the baseline speed reaches the preset ratio of the critical speed, the trajectory adjustment condition is triggered. Specifically, to ensure that the brushless actuator can adjust its trajectory in a timely manner when approaching the maximum speed range allowed by the current load conditions, a reference speed curve and a critical speed threshold can be compared in real time. When the actuator executes according to the reference trajectory, the speed value corresponding to the reference speed curve can be read at each moment and compared with the critical speed threshold at the same moment to determine whether the actuator has approached its safe speed limit under the current load conditions. To improve the accuracy of the judgment and avoid triggering the adjustment immediately when the speed is just close to the critical speed, a trigger ratio can be preferably set, such as 80% or 90%, as the trigger condition for the reference speed relative to the critical speed threshold. When the reference speed reaches or exceeds this ratio, it is considered that the actuator is about to enter a high-risk speed range and trajectory adjustment is required to prevent further speed increase and impact or instability. In a preferred embodiment, an adjustable trigger ratio can be set, allowing for appropriate modification based on different application scenarios or user stability requirements. For example, in scenarios with significant load variations, the preset ratio can be set lower to trigger trajectory adjustments earlier; while in scenarios with lighter loads, the trigger ratio can be set higher, enabling the actuator to utilize speed more effectively while maintaining safety. This method allows for timely judgment and triggering of trajectory adjustment conditions when the reference speed approaches the critical speed threshold, thus providing a prerequisite for subsequent trajectory correction and improving the overall stability and safety of the actuator's operation.

[0024] S4: After triggering the trajectory adjustment condition, establish a dynamic speed constraint by associating the critical speed threshold with the reference speed curve, and attenuate and reconstruct the reference motion trajectory based on the dynamic speed constraint to obtain the final trajectory control strategy.

[0025] Specifically, once the trajectory adjustment condition is triggered, the original reference speed curve can be constrained using the current critical speed threshold to generate dynamic speed constraints suitable for the current load conditions. First, the reference speed curve is compared moment-by-moment with the speed limit corresponding to the critical speed threshold, and the reference speed at each moment is correlated with the maximum allowed speed at that moment. This is used to limit the highest executable speed of the push rod in that phase. The resulting dynamic speed constraints reflect the speed limit changes of the push rod at different positions and under different loads throughout the entire motion cycle. Based on this, the reference motion trajectory can be attenuated and reconstructed, gradually reducing potentially excessively high speed segments to within the dynamic speed constraint range. For example, if the reference speed exceeds the dynamic constraint speed limit in a certain segment, it can be preferentially attenuated by gradually decreasing the speed to keep the speed change smooth and prevent sudden drops, thereby avoiding additional shocks or discontinuous changes. The reconstructed trajectory obtained through the above method can better meet the safe operation requirements under the current load conditions, while ensuring the continuity and executability of the overall motion process. The velocity curve and acceleration curve after reconstruction constitute the final trajectory control strategy used to drive the brushless push rod, enabling the push rod to maintain a stable and safe motion state when the load changes or approaches the limit conditions.

[0026] This invention effectively solves the problem of shock and safety issues caused by existing brushless actuators running along a fixed trajectory when the load changes, thus improving the smoothness of actuator control and operational safety.

[0027] As a preferred embodiment of the above, the trajectory adjustment condition further includes: triggering the trajectory adjustment condition when the predicted displacement of the reference motion trajectory is about to enter the safety boundary, wherein the safety boundary is determined based on the remaining distance between the current position of the push rod and the travel limit.

[0028] Specifically, to further improve the safety of brushless linear actuators when approaching their limits, a trajectory adjustment trigger mechanism based on predicted displacement can be added, in addition to the judgment based on critical speed thresholds. Specifically, as the actuator moves along a baseline trajectory, the current position, velocity, and acceleration information of the actuator are combined to predict the position the actuator might reach in the near future. By predicting the displacement trend of the actuator, it is possible to determine in advance whether the actuator might enter a dangerous area. To clearly define the danger zone, a safety boundary can be set based on the remaining distance between the current position of the push rod and its travel limit. This safety boundary is typically set slightly earlier than the actual travel limit, allowing the push rod a buffer distance before reaching its limit position. In a preferred approach, the size of the safety boundary can be set in conjunction with the push rod's movement speed, load variation trends, and the safety requirements of the usage scenario. For example, under high load conditions, the safety boundary can be set larger to provide sufficient attenuation space. When the predicted displacement indicates that the push rod will enter this safety boundary in the near future, the trajectory adjustment condition can be triggered, allowing subsequent trajectory planning to reduce speed or make other necessary trajectory modifications in advance. This avoids the push rod approaching its travel limit before abruptly decelerating, reducing the risk of impact. Through this prediction-based triggering method, even under conditions of rapid load changes or fast push rod movement, trajectory adjustment can be intervened in advance, making the overall movement process smoother and safer.

[0029] As a preferred embodiment of the above, such as Figure 2 As shown, step S2, calculating the critical speed threshold corresponding to the current load condition based on the motor current and external load force, includes: S21: Calculate the instantaneous output thrust of the brushless push rod based on the motor current detection value; S22: Determine the equivalent load of the push rod under the current working condition based on the external load force; S23: Establish a mechanical balance relationship based on the instantaneous output thrust and the equivalent load, and calculate the maximum allowable speed of the push rod under the current working conditions. The maximum allowable speed is the critical speed threshold.

[0030] Specifically, firstly, the instantaneous output thrust of the brushless actuator is estimated based on its current operating current. During the structural design and production calibration of brushless DC motors, a correspondence between current and output torque is typically established. This relationship allows the current operating current of the motor to be converted into the corresponding output capacity. In the actuator, the motor output is transmitted step-by-step through the reduction mechanism, lead screw structure, and guide structure into a pushing force along the actuator direction. Therefore, when determining the actual thrust, it is preferable to correct the thrust calculated from the current based on the reduction characteristics of the internal transmission mechanism of the actuator, the load conversion efficiency of the lead screw structure, and friction variations. It more closely approximates the actual output capacity of the push rod under real motion conditions. For example, if the friction of the lead screw mechanism increases significantly under high load, the calculated thrust can be reduced proportionally; if the internal structure of the push rod has been lubricated and maintained, the effective utilization ratio in the converted thrust can be appropriately increased; then, the equivalent load of the push rod under the current working condition is determined based on the external load force. The external load force may come from the weight of the furniture structure, the pressure of the human body, the component force caused by the change of the transmission angle of the mechanism, or the additional resistance formed by the deviation of the force direction of the push rod under different postures. In this embodiment, according to the structural characteristics of the device where the push rod is located, the load sensor, Angle feedback or typical usage scenario parameters are used to obtain the magnitude of the external load force, which is then converted along the direction of the push rod's movement to become the effective load that the push rod must overcome during its movement. For example, when the push rod is used to lift a structure, the additional load caused by the gravitational component on the push rod can be estimated based on the current tilt angle of the structure. If the push rod carries the weight of a person, the load measured at the initial movement can also be used as a reference value for the equivalent load to ensure the accuracy and continuity of the load. Finally, the maximum allowable speed of the push rod is determined based on the balance between the instantaneous output thrust and the equivalent load. Since the push rod experiences significant changes in output thrust and inertia during high-speed movement... Higher demands are placed on both overcoming resistance and acceleration capabilities. When the instantaneous output thrust is close to equilibrium with the equivalent load, the upper limit of the safe speed achievable by the push rod will be significantly reduced. Conversely, when the instantaneous output thrust has a significant margin relative to the equivalent load, the speed range in which the push rod can maintain stability will expand. In practical applications, the maximum permissible speed can be determined according to the following principles: when the push rod still has a large thrust margin under the current load, the maximum permissible speed should be set to a higher value; when the thrust margin is insufficient or the load fluctuates, the maximum permissible speed can be appropriately reduced to better match the push rod's load-bearing capacity. For example, when the push rod lifts a heavy structure, the thrust margin decreases significantly, and the maximum permissible speed can be adjusted to be closer to the low-speed range; when the push rod is under a light load, the maximum permissible speed can be appropriately increased to enhance motion efficiency. The maximum permissible speed determined in the above manner can be used as a critical speed threshold to reflect the upper limit of the speed at which the push rod can operate stably under the current working conditions without generating shock, stall, or overload risks.

[0031] As a preferred embodiment of the above, such as Figure 3 As shown, establishing dynamic speed constraints by associating the critical speed threshold with the reference speed curve includes: A10: The critical speed threshold is updated in real time based on the real-time operating information of the brushless actuator; A20: The updated critical speed threshold is used as the speed limit, and compared with the baseline speed curve time by time to obtain a dynamic speed limit curve based on the time series. A30: When the reference speed curve exceeds the corresponding speed value of the dynamic speed limit curve at any moment, the corresponding speed value will be taken as the target speed at that moment; A40: Construct a target velocity curve based on the target velocity at each time point, and use the target velocity curve as a dynamic velocity constraint.

[0032] Specifically, firstly, the critical speed threshold is updated based on real-time operating information of the brushless actuator during operation. This real-time operating information includes changes in the actuator's current motor current, external load trends, motion posture, and friction conditions. By comprehensively judging this information, the upper limit of the actuator's allowable speed at the current moment can be obtained. Since the actuator's load may change rapidly with its movement position or operating environment, real-time updates to the critical speed threshold help make the speed limit more closely match actual operating capabilities. Then, the updated critical speed threshold is used as the upper limit and compared with the baseline speed curve moment by moment to form a dynamic speed limit curve based on a time series. Each speed point on the baseline speed curve can be compared with the corresponding critical speed threshold at the current moment. When the critical speed is high, the baseline speed can maintain a high value at that stage; when the critical speed decreases with increasing load, the baseline speed will be subject to stricter limitations at that stage. Through this moment-by-moment comparison method, the allowable speed limit can be determined. A dynamic speed limit curve reflecting the real-time safe speed limit is formed. Subsequently, when the reference speed curve exceeds the speed value of the dynamic speed limit curve at a certain moment, the corresponding speed of the dynamic speed limit curve can be used as the target speed at that moment to prevent the push rod from continuing to run at the original reference speed and potentially entering the risk zone. In a preferred embodiment, the target speed can be set slightly lower than the boundary of the dynamic speed limit curve to provide a certain safety margin for subsequent trajectory reconstruction. Finally, a continuous target speed curve is constructed based on the target speed points corresponding to each moment, and this curve is used as a dynamic speed constraint to limit the subsequent trajectory planning process. When constructing the target speed curve, a smooth transition method can be preferred to make the speed change coherent and avoid unnecessary speed gaps or sudden drops. The dynamic speed constraint obtained through the above steps can adapt to the load changes of the push rod in real time, so that the push rod can adjust its speed in time when it approaches the load limit or stroke limit, thereby improving the overall operational safety and trajectory tracking stability.

[0033] As a preferred embodiment of the above, such as Figure 4 As shown, attenuation reconstruction includes: B10: Limit the reference speed curve to obtain the limited speed sequence; B20: Construct a target acceleration sequence based on the limited velocity sequence, and perform constraint smoothing on the limited velocity sequence and the target acceleration sequence under dynamic velocity constraints.

[0034] Specifically, firstly, the baseline speed curve is subjected to amplitude limiting processing to obtain an amplitude-limited speed sequence. The amplitude limiting process can be understood as checking the baseline speed curve moment by moment and cutting off the speed points that exceed the dynamic speed constraint or the preset safe speed range so that they do not exceed the upper limit value. In a preferred method, a flexible amplitude limiting method can be adopted, that is, instead of directly cutting the speed to a certain fixed extreme value, the excess part is weakened proportionally according to the magnitude of the deviation to avoid the speed curve from having a sudden angle. For example, when the reference speed is significantly higher than the allowable speed range within a short period, the speed in that segment can be gradually reduced by a certain proportion, so that the reduced speed sequence presents a natural transition in the time dimension, thereby improving the continuity of subsequent trajectory reconstruction. Then, a target acceleration sequence is further constructed based on the limited speed sequence, so that the speed adjustment process can be controlled step by step. When constructing the target acceleration sequence, it is preferable to determine the acceleration value based on the changing trend between adjacent speed points, so that there are no sudden increases or decreases throughout the entire motion cycle. For example, when the limited speed sequence shows a downward trend in a certain segment, the target acceleration can be set to a slow deceleration that matches the trend. When the speed change tends to be stable, the target acceleration can be appropriately reduced to maintain the smoothness of the trajectory. Subsequently, under the action of dynamic speed constraints, the limited speed sequence and the constructed target acceleration sequence are subjected to constraint smoothing processing. This processing can coordinate the continuity of the speed curve and the acceleration curve according to actual needs, so that the final generated speed and acceleration changes are kept within a safe range. In practical operation, a segmented smoothing method is preferred, which involves adjusting local segments where the velocity and acceleration change abruptly to make the velocity changes smoother and the acceleration changes more natural. The attenuation reconstruction results generated by the above steps ensure that the push rod does not exhibit abrupt braking or acceleration behavior during trajectory adjustment, thus enabling the final trajectory control strategy to meet both dynamic velocity constraints and good execution stability.

[0035] As a preferred embodiment of the above, the amplitude limiting process is based on an S-shaped trajectory planning function or an exponential decay function.

[0036] Specifically, to make the speed change smoother after the amplitude limiting process, an S-shaped trajectory planning function or an exponential decay function is used to limit the baseline speed curve. When the baseline speed exceeds the upper limit allowed by the dynamic speed constraint at a certain moment or within a certain continuous time period, the excess area can be identified first, and the above functions can be used to attenuate and correct the speed value in that segment. For example, when using an S-shaped trajectory planning function for amplitude limiting, the speed can be gradually reduced to the allowable range by making the speed transition slowly at both ends of the over-limit segment. This method allows the speed change to exhibit a typical gradual increase-smoothness-gradient characteristic, giving the speed curve better continuity and executability in time, making it suitable for applications requiring high motion smoothness. In another preferred method, an exponential decay function can be used to reduce the over-limit speed. That is, based on the deviation between the over-limit speed and the allowable speed, the speed value is gradually reduced according to a certain proportion, showing a natural decay trend. For example, when the over-limit amplitude is large, the decay ratio can be increased to achieve rapid reduction; while when the over-limit amplitude is small or close to the allowable range, a gentler decay method can be used to allow the speed value to naturally fit the dynamic speed constraint curve. The above two methods can be selected according to actual needs, making the speed curve after amplitude limiting smoother and without abrupt changes, thus laying a good foundation for subsequent trajectory reconstruction.

[0037] As a preferred embodiment of the above, before attenuation reconstruction, the method further includes: determining the trajectory interval that needs to be attenuated based on dynamic velocity constraints, wherein the trajectory interval is obtained by identifying the time period in the reference velocity curve that exceeds the dynamic velocity constraints.

[0038] Specifically, the dynamic velocity constraints are sequentially compared with the baseline velocity curve in the time dimension, identifying the time periods during which the baseline velocity exceeds the allowable speed of the dynamic velocity constraints at any given moment. To ensure the integrity and continuity of the intervals, the identification process considers not only the actual moment when the baseline velocity exceeds the constraint but also adjacent regions before and after these moments, ensuring smooth transitions in the velocity changes within the intervals. For example, if the baseline velocity is slightly higher than the dynamic velocity constraint for a short period, processing only this short segment might cause abrupt changes in the subsequent trajectory. Therefore, it is preferable to extend this segment forward or backward by a certain time to form a continuous interval. In practical applications, all points exceeding the dynamic velocity constraints can be identified by scanning time-by-time, and these points can be divided into one or more attenuation intervals based on their temporal continuity. These intervals can then be processed separately in the subsequent attenuation reconstruction steps, making the adjustment of the entire velocity curve more holistic and stable. The trajectory intervals determined in the above manner accurately reflect the velocity segments that need adjustment, providing clear processing targets for subsequent attenuation reconstruction, thereby ensuring the targetedness and effectiveness of trajectory reconstruction.

[0039] As a preferred embodiment of the above, such as Figure 5 As shown, after the attenuation reconstruction is completed, it includes: C10: Identify the connection boundary between the attenuated trajectory and the unattenuated trajectory; C20: Perform continuity check on velocity and acceleration at the connection boundary; C30: When a discontinuity in velocity or acceleration is detected, local smoothing correction is performed on several trajectory points at the connection boundary; C40: Generate a reconstructed trajectory that satisfies both velocity and acceleration continuity based on the correction results.

[0040] Specifically, after completing the attenuation reconstruction of the baseline motion trajectory, further continuity processing can be performed on the connection point between the attenuated trajectory and the original trajectory that did not participate in the attenuation process to ensure the smoothness of the overall trajectory in terms of velocity and acceleration. First, the connection boundary between the attenuated trajectory and the unattenuated trajectory is identified. This boundary is usually located at the beginning or end of the attenuation interval and can be determined by the corresponding dividing point on the time axis based on the time range of the attenuation segment. Then, the velocity and acceleration at this connection boundary are checked for continuity, i.e., whether the attenuated velocity and acceleration can naturally connect with the velocity and acceleration of the unattenuated segment. In a preferred method, the velocity trend at the end of the attenuation segment can be compared with the velocity trend at the beginning of the unattenuated segment. If there is a sudden change in direction or the change is too steep, it is determined that the velocity continuity is insufficient. Similarly, the acceleration change trends of the two segments can be compared to determine whether there is a sudden jump in acceleration. For example, when the velocity of the attenuated trajectory at the boundary meets the dynamic velocity constraints, but its acceleration direction or magnitude differs significantly from the original trajectory, it will cause the push rod to produce a sudden mechanical response at the boundary, thus requiring further correction. Subsequently, when detecting... When discontinuities in velocity or acceleration are found, a local smoothing correction is performed on a small segment of trajectory points near the connection boundary. This type of correction typically involves adjusting the velocity change trends at several moments before and after the boundary, allowing the two trajectories to gradually transition in velocity and acceleration. For example, several trajectory points can be selected before and after the connection point, and the velocities of these points can be moderately adjusted to make the velocity change distribution more natural. Simultaneously, the acceleration is adjusted so that its direction of change gradually becomes consistent, thus eliminating discontinuities. In this local smoothing process, a gradual adjustment method can be preferred, that is, the difference between each trajectory point is gradually reduced to make the transition smoother. Finally, based on the corrected results, a reconstructed trajectory that satisfies the continuity of velocity and acceleration is regenerated. This reconstructed trajectory no longer exhibits abrupt changes at the boundary, and the changes in velocity and acceleration show a smooth transition, making the overall trajectory more suitable for actual execution and further improving the stability and reliability of the brushless actuator in the motion control process.

[0041] Example 2: The reference trajectory generation module generates the reference motion trajectory of the brushless push rod based on the load dynamics model of the brushless push rod. The reference motion trajectory includes the reference velocity curve and the reference acceleration curve. The speed threshold calculation module calculates the critical speed threshold corresponding to the current load condition based on the motor current and external load force. The trajectory adjustment trigger module compares the baseline speed curve with the critical speed threshold. When the baseline speed reaches a preset ratio of the critical speed, the trajectory adjustment condition is triggered. The control strategy generation module, after triggering the trajectory adjustment conditions, establishes dynamic speed constraints by associating the critical speed threshold with the reference speed curve, and attenuates and reconstructs the reference motion trajectory based on the dynamic speed constraints to obtain the final trajectory control strategy.

[0042] Based on the same inventive concept as the trajectory control method for a brushless linear actuator in the foregoing embodiments, the present invention also provides a trajectory control system for a brushless linear actuator, comprising: The control system described above in this invention can effectively realize the trajectory control method of the brushless push rod, and the technical effects it can achieve are as described in the above embodiments, which will not be repeated here.

[0043] As a preferred embodiment of the above, the speed threshold calculation module includes: The instantaneous thrust calculation unit calculates the instantaneous output thrust of the brushless push rod based on the detected motor current value. The equivalent load determination unit determines the equivalent load of the push rod under the current working condition based on the external load force. The maximum speed calculation unit establishes a mechanical balance relationship between the instantaneous output thrust and the equivalent load, and calculates the maximum allowable speed of the push rod under the current working conditions. The maximum allowable speed is the critical speed threshold.

[0044] Similarly, the above-mentioned optimization schemes for the system can also achieve the optimization effects corresponding to the methods in Embodiment 1, which will not be repeated here.

[0045] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A trajectory control method for a brushless linear actuator, characterized in that, The method includes: Based on the load dynamics model of the brushless linear actuator, a reference motion trajectory of the brushless linear actuator is generated, which includes a reference velocity curve and a reference acceleration curve. Calculate the critical speed threshold corresponding to the current load condition based on the motor current and external load force; The baseline speed curve is compared with the critical speed threshold. When the baseline speed reaches a preset ratio of the critical speed, the trajectory adjustment condition is triggered. After the trajectory adjustment condition is triggered, the critical speed threshold is associated with the reference speed curve to establish a dynamic speed constraint, and the reference motion trajectory is attenuated and reconstructed based on the dynamic speed constraint to obtain the final trajectory control strategy.

2. The trajectory control method for the brushless actuator according to claim 1, characterized in that, The trajectory adjustment condition further includes: triggering the trajectory adjustment condition when the predicted displacement of the reference motion trajectory is about to enter the safety boundary, wherein the safety boundary is determined based on the remaining distance between the current position of the push rod and the travel limit.

3. The trajectory control method for the brushless push rod according to claim 1, characterized in that, Calculate the critical speed threshold corresponding to the current load condition based on the motor current and external load force, including: Calculate the instantaneous output thrust of the brushless push rod based on the detected motor current value; Based on the external load force, determine the equivalent load of the push rod under the current working condition; Based on the mechanical balance relationship established between the instantaneous output thrust and the equivalent load, the maximum permissible speed of the push rod under the current working condition is calculated, and the maximum permissible speed is the critical speed threshold.

4. The trajectory control method for the brushless push rod according to claim 1, characterized in that, Establishing dynamic speed constraints by associating the critical speed threshold with the reference speed curve includes: The critical speed threshold is updated in real time based on the real-time operating condition information of the brushless actuator. The updated critical speed threshold is used as the upper speed limit, and compared with the baseline speed curve time by time to obtain a dynamic speed limit curve based on the time series. When the reference speed curve exceeds the corresponding speed value of the dynamic speed limit curve at any moment, the corresponding speed value is taken as the target speed at that moment. A target velocity curve is constructed based on the target velocity at each time point, and the target velocity curve is used as the dynamic velocity constraint.

5. The trajectory control method for the brushless push rod according to claim 1, characterized in that, The attenuation reconstruction includes: The reference velocity curve is subjected to amplitude limiting processing to obtain an amplitude-limited velocity sequence; A target acceleration sequence is constructed based on the limited velocity sequence, and the limited velocity sequence and the target acceleration sequence are subjected to constraint smoothing under the dynamic velocity constraint.

6. The trajectory control method for a brushless actuator according to claim 5, characterized in that, The amplitude limiting process is based on an S-shaped trajectory planning function or an exponential decay function.

7. The trajectory control method for a brushless actuator according to claim 1, characterized in that, Before the attenuation reconstruction, the method further includes: determining the trajectory interval that needs to be attenuated based on the dynamic velocity constraint, wherein the trajectory interval is obtained by identifying the time period in the reference velocity curve that exceeds the dynamic velocity constraint.

8. The trajectory control method for a brushless actuator according to claim 1, characterized in that, After completing the attenuation reconstruction, the following is included: Identify the connection boundary between the decayed trajectory and the undecayed trajectory; The velocity and acceleration at the connection boundary are continuously checked; When a discontinuity in the velocity or acceleration is detected, local smoothing correction is performed on several trajectory points at the connection boundary. Based on the correction results, a reconstructed trajectory that satisfies both velocity and acceleration continuity is generated.

9. A trajectory control system for a brushless linear actuator, characterized in that, The system includes: The reference trajectory generation module generates a reference motion trajectory for the brushless push rod based on the load dynamics model of the brushless push rod. The reference motion trajectory includes a reference velocity curve and a reference acceleration curve. The speed threshold calculation module calculates the critical speed threshold corresponding to the current load condition based on the motor current and external load force. The trajectory adjustment trigger module compares the reference speed curve with the critical speed threshold, and triggers the trajectory adjustment condition when the reference speed reaches a preset ratio of the critical speed. The control strategy generation module, after triggering the trajectory adjustment condition, associates the critical speed threshold with the reference speed curve to establish a dynamic speed constraint, and performs attenuation reconstruction on the reference motion trajectory based on the dynamic speed constraint to obtain the final trajectory control strategy.

10. The trajectory control system for the brushless push rod according to claim 9, characterized in that, The velocity threshold calculation module includes: The instantaneous thrust calculation unit calculates the instantaneous output thrust of the brushless push rod based on the detected motor current value. The equivalent load determination unit determines the equivalent load of the push rod under the current working condition based on the external load force. The maximum speed calculation unit establishes a mechanical balance relationship between the instantaneous output thrust and the equivalent load, and calculates the maximum permissible speed of the push rod under the current working condition. The maximum permissible speed is the critical speed threshold.

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