Collision detection method and system suitable for liquid transfer device

Abstract

The invention relates to the technical field of medical instruments, and provides a collision detection method and system, and the method comprises the steps: obtaining the real-time stress data of an execution part in a process of controlling the execution part to move to a target position, and the real-time stress data comprises a strain signal value provided by a strain sensor; according to the real-time stress data, whether a stress change value of the execution part meets a collision triggering condition or not within specified time is monitored, and the stress change value is the fluctuation amplitude of the strain signal value relative to the strain reference value; after the collision triggering condition is met, the stress change acceleration condition of the execution part is determined according to the real-time stress data within the specified time; and when the stress change acceleration condition is in an abnormal acceleration state, judging that the execution part is collided. According to the invention, high-precision collision detection can be realized, the anti-interference capability is strong, and the collision damage of the liquid transfer part can be effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a collision detection method and collision detection system suitable for liquid transfer devices. Background Technology

[0002] In automated medical testing equipment, the liquid transfer component is the core actuator for the aspiration, dispensing, and mixing of samples and reagents. It is usually designed as a needle-shaped component and, under the action of the drive mechanism, accurately positions containers such as reaction cups and test tubes in the target location. If the liquid transfer component is damaged due to positioning errors, container placement deviations, liquid foam, or foreign object intrusion, it is very easy to collide with obstacles.

[0003] Existing collision detection methods mainly fall into two categories: electromechanical sensor solutions (such as microswitches) and environment-dependent solutions (such as photoelectric sensors). Electromechanical sensor solutions rely on physical contact for conduction, requiring significant displacement (≥2mm) and a long response time (>5ms) to trigger, making them unable to detect minute, instantaneous collisions and exhibiting severe response lag, thus failing to effectively protect liquid-transferring components. Photoelectric sensor solutions, on the other hand, are easily affected by lighting conditions, such as liquid reflections, transparent obstacles, and dim lighting, resulting in high false alarm and false negative rates, as well as system complexity and high cost. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a collision detection method and collision detection system suitable for liquid transfer devices, which has the characteristics of high sensitivity and high reliability, can achieve high-precision collision detection, has strong anti-interference ability, and can effectively prevent collision damage to liquid transfer components.

[0005] In a first aspect, the present invention provides a collision detection method suitable for a liquid transfer device, the liquid transfer device comprising a driving component and an actuator for liquid transfer, the driving component being used to drive the actuator to move, the actuator being provided with a strain sensor, the method comprising: During the process of controlling the actuator to move to the target position, real-time stress data about the actuator is acquired, including strain signal values ​​provided by the strain sensor; Based on the real-time stress data, monitor whether the stress change value of the actuator meets the collision triggering condition within a specified time. The stress change value is the fluctuation amplitude of the strain signal value relative to the strain reference value. After the collision triggering condition is met, the acceleration of stress change in the actuator is determined based on the real-time stress data within the specified time period. When the stress change acceleration is in an abnormal acceleration state, it is determined that the actuator has collided. The strain signal value is acquired once per unit time, and the collision triggering condition includes: Determine whether the fluctuation amplitude of the strain signal values ​​acquired multiple times in succession relative to the strain reference value is not less than a first threshold. If so, it is determined that the stress change value of the actuator satisfies the collision triggering condition.

[0006] According to the collision detection method provided in the first aspect of the present invention, the strain signal obtained by the strain sensor is analyzed in real time while the stress data is acquired in real time. If the stress change value meets the collision triggering condition within a specified short period of time, it can be quickly determined that a collision has occurred in the current actuator. Combined with motion parameters and load state, precise control is achieved. By judging the stress, micron-level deformation can be identified. The sensitivity is significantly improved compared with the prior art. It is not affected by ambient light, electromagnetic field, liquid properties, etc., has strong anti-interference ability, and its reliability is far higher than that of the collision detection scheme in the prior art.

[0007] In a preferred embodiment of the present invention, the collision triggering condition further includes: when the actuator is in an accelerated movement state, correcting the strain reference value based on the inertial force of the actuator; the correction of the strain reference value based on the inertial force of the actuator includes: determining a correction amount based on the inertial force of the actuator, and adding the correction amount to the original strain reference value to obtain the corrected strain reference value.

[0008] In a preferred embodiment of the present invention, the first threshold is set as a dynamic threshold obtained by correcting the allowable strain of the actuator based on the driving speed of the driving component and the liquid absorption amount of the actuator.

[0009] In a preferred embodiment of the present invention, the first threshold is determined based on the following formula: a = p * [1 - f(v, q)] Where a is the first threshold, p is the allowable strain, f(v,q) is the dynamic correction coefficient, v is the driving speed of the driving component, and q is the liquid absorption amount of the actuator.

[0010] In the dynamic correction coefficient f(v,q), f(v,q)=k1*v+k2*q Where k1 is the velocity coefficient and k2 is the liquid absorption coefficient.

[0011] In a preferred embodiment of the present invention, the collision triggering condition further includes: when the driving component is in a first abnormal operating condition, the first threshold is equal to the product of the allowable strain and the set coefficient; wherein, under the first abnormal operating condition, the driving speed of the driving component is in an abnormal state; the determination condition for the driving speed of the driving component to be in an abnormal state is as follows: the driving speed is less than a first set speed or greater than a second set speed, and the second set speed is greater than the first set speed; the first threshold being equal to the product of the allowable strain and the set coefficient when the driving component is in the first abnormal operating condition includes: when the driving speed is less than the first set speed, the first threshold is equal to the product of the allowable strain and the first set coefficient; when the driving speed is greater than the second set speed, the first threshold is equal to the product of the allowable strain and the second set coefficient; wherein, both the first set coefficient and the second set coefficient are less than 1 and the first set coefficient is greater than the second set coefficient.

[0012] In a preferred embodiment of the present invention, the driving component is a stepper motor, and the method further includes: When the driving speed is less than the first set speed, the driving component is controlled to enter a creeping state; when the driving speed is greater than the second set speed, the driving speed of the driving component is controlled to not exceed the second set speed; when the duration of the driving speed being greater than the second set speed is greater than a set time, the driving action of the driving component is stopped.

[0013] In a preferred embodiment of the present invention, the collision triggering condition further includes: when the actuator is in a second abnormal operating condition, correcting the liquid absorption coefficient in the first threshold, or making the first threshold equal to the product of the allowable strain and the specified coefficient; wherein, under the second abnormal operating condition, the liquid absorption of the actuator is in an abnormal state.

[0014] In a preferred embodiment of the present invention, the determination condition for the liquid absorption volume of the actuator to be in an abnormal state is as follows: the liquid absorption volume exceeds the maximum absorption range of the actuator or the liquid absorption volume is negative; when the actuator is in a second abnormal operating condition, the liquid absorption coefficient in the first threshold is corrected, or the first threshold is made equal to the product of the allowable strain and the specified coefficient, including: when the liquid absorption volume exceeds the maximum absorption range of the actuator, the liquid absorption coefficient is increased; when the liquid absorption volume is negative, the first threshold is made equal to the product of the allowable strain and the specified coefficient.

[0015] In a preferred embodiment of the present invention, determining the stress change acceleration of the actuator based on the real-time stress data within the specified time period includes: determining the stress change rate of the actuator within the specified time period by using strain signal values ​​within the specified time period; determining that the stress change acceleration is in an abnormal acceleration state includes: determining that the stress change acceleration is in an abnormal acceleration state when the stress change rate is greater than a second threshold.

[0016] In a second aspect, the present invention provides a collision detection system suitable for a liquid transfer device, the liquid transfer device comprising a driving component and an actuator for liquid transfer, the driving component for driving the actuator to move, the actuator being provided with a strain sensor, and the liquid transfer device comprising: An execution unit is used to control the drive component to move the actuator and to control the actuator to transfer liquid; The acquisition unit is used to acquire real-time stress data of the actuator, the real-time stress data including strain signal values ​​provided by the strain sensor, the strain signal values ​​being acquired once per unit time. The monitoring unit is used to monitor whether the stress change value of the actuator meets the collision triggering condition within a specified time according to the real-time stress data, wherein the stress change value is the fluctuation amplitude of the strain signal value relative to the strain reference value. The processing unit is configured to, after the monitoring unit determines that the collision triggering condition is met, determine the stress change acceleration of the actuator based on the real-time stress data within the specified time period, and determine that the actuator has experienced a collision when the stress change acceleration is in an abnormal acceleration state. The collision triggering conditions include: Determine whether the fluctuation amplitude of the strain signal values ​​acquired multiple times in succession relative to the strain reference value is not less than a first threshold. If so, it is determined that the stress change value of the actuator satisfies the collision triggering condition.

[0017] In a third aspect, the present invention provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, which, when executed by a processor, performs the collision detection method suitable for a liquid transfer device as described in the first aspect embodiment.

[0018] Other features and advantages of the invention will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures and / or processes particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the liquid transfer device provided in an embodiment of the present invention;

[0020] Figure 2 A flowchart of a collision detection method provided in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the collision detection system provided in an embodiment of the present invention. Detailed Implementation

[0022] The following detailed description of the embodiments of the present invention, in conjunction with the accompanying drawings, will provide a thorough understanding of how the present invention uses technical means to solve technical problems and achieve technical effects, enabling its implementation. It should be noted that these specific descriptions are merely intended to facilitate a clearer understanding of the present invention by those skilled in the art, and are not intended to limit the scope of the invention. For example, the terms "first" and "second" mentioned in the embodiments of the present invention are not intended to limit the invention, but are merely used to indicate the sequence numbers of multiple identical or similar devices or mechanisms. Those skilled in the art can readjust these sequence numbers for ease of description or during the organization of technical solutions. Furthermore, alternative solutions are described for some mechanisms in different embodiments, and these alternatives can be applied to other identical or similar devices or mechanisms. As long as there is no conflict, the various embodiments and features in each embodiment of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0023] Current automated medical testing equipment often uses liquid transfer components to achieve the transfer, aspiration, and dispensing of samples and reagents, for example, see [reference needed]. Figure 1A liquid transfer device provided herein includes a drive component 3, a pipetting arm 2, and an actuator 1 disposed on the pipetting arm 2. The actuator 1 is connected to a suction device, which provides negative pressure to allow the actuator 1 to draw in liquid and provides positive pressure to expel liquid from the actuator 1. Typically, the actuator 1 can be implemented as a needle-like structure, with a storage space for storing liquid inside. Its bottom end has a liquid inlet / outlet communicating with the storage space, while the other end of the bottom end is connected to the suction device. The liquid inlet / outlet is used to draw liquid into the storage space and to expel liquid from the storage space. To facilitate liquid transfer, the actuator 1 is usually positioned at the bottom of the pipetting arm 2. However, the actuator 1 is easily damaged in the event of a collision; therefore, collision sensing and braking of the actuator 1 are necessary. The driving component 3 can be configured as an XYZ three-axis driving mechanism, which drives the pipette arm 2 through three sliding components located in the three axes. In this embodiment, it can also be configured as a dual-axis driving mechanism, with a rotating shaft connecting the pipette arm 2, causing the pipette arm 2 to rotate around a specified axis. The pipette arm 2 is mounted on a lifting mechanism, such as a lifting slide rail combined with a drive motor, to drive the pipette arm 2 to move up and down. Thus, the pipette arm 2, combined with the action of the dual-axis driving mechanism, causes the actuator 1 to move within a specified area. Of course, the driving component 3 can also be configured with other feasible structures in the prior art, all of which are within the scope of this invention.

[0024] The liquid transfer device can be used for sample, mixture, or reagent transfer. For example, during dilution, the actuator 1 moves to a first target location containing the diluent via the drive component 3, aspirates the diluent at the first target location, and transfers it to a mixing station at a second target location. Subsequently, it continues to aspirate the sample from a third target location containing a sample container, moves it to the second target location, and discharges the sample to the mixing station to mix it, thereby achieving the sample dilution process. Similarly, when it is necessary to transfer the liquid to other locations, the liquid transfer is also achieved through the drive component 3 in conjunction with a suction device.

[0025] Taking the aforementioned embodiment as an example, during the liquid transfer process, obstacles may exist on the movement trajectory of the actuator 1. For example, the container holding the reagent may obstruct the movement trajectory due to its height, or the actuator 1 may collide with the obstacle because the device fails to detect obstacles such as the workbench in front of it. Therefore, it is necessary to install a sensing component on the liquid transfer device to detect whether the actuator 1 has collided, so as to avoid further collisions and damage to the actuator 1.

[0026] To prevent damage to the actuator 1 due to collision, this liquid transfer device is equipped with a strain sensor to detect whether the actuator 1 has collided. This strain sensor is installed on the actuator 1 to sense stress changes. Specifically, when stress is generated in the actuator 1, the strain sensor converts the stress or strain of the actuator 1 into an electrical signal and feeds it back to the control system. The control system analyzes these electrical signals to achieve real-time monitoring of the current state of the actuator 1. In one embodiment, the strain sensor can be implemented as a strain gauge sensor (also known as a resistive strain gauge sensor), using a resistive strain gauge as the core element. It detects the strain signal generated by the deformation of an object under force and converts it into a change in resistance to obtain the stress change of the actuator 1.

[0027] See further Figure 1 In this embodiment, the actuator 1 is configured as a needle-shaped liquid transfer component, with one end rigidly connected to the end of the pipetting arm 2 and the other end serving as the liquid inlet / outlet. This forms a cantilever beam structure between the actuator 1 and the pipetting arm 2. A strain sensor can be mounted on the connecting arm or the liquid transfer component. In this embodiment, the strain gauge 4 of the strain sensor is mounted on the liquid transfer component and attached to a distance of approximately 1 / 4 of its own length from the connecting seat. The strain sensor is also mounted on the outer wall of the actuator 1, a location within a strain concentration area, which amplifies minute deformation signals and avoids interference with strain during normal movement of the actuator 1. When the pipetting arm 2 moves horizontally, it drives the actuator 1 to move horizontally as well. If a mechanical collision occurs, the strain sensor can quickly detect the minute mechanical deformation (micrometer level) caused by the collision. Alternatively, the actuator 1 can also be configured with a connecting arm and a needle-shaped liquid transfer component rigidly connected along its length, forming a cantilever beam structure with the pipetting arm 2. A strain sensor can be mounted on the connecting arm or the needle-shaped component, similarly enabling the strain sensor to detect stress changes in the liquid transfer component. Of course, other structures that can effectively detect stress changes in actuator 1 are also within the scope of this invention, and will not be described in detail here.

[0028] Next, in its first aspect, the present invention proposes a collision detection method for liquid transfer devices, which enables accurate identification of collision states and prevents damage to actuators. (See attached document.) Figure 2 Specifically, it includes: S100: During the process of controlling the actuator to move to the target position, real-time stress data about the actuator is acquired. The real-time stress data includes strain signal values ​​provided by strain sensors. The strain signal value is the electrical signal generated by the strain sensor at the sensing position due to stress on the actuator, resulting in stress deformation. This electrical signal is reflected in the control system as both a signal value and a strain signal value. In this embodiment, when there is no stress on the actuator, the strain gauge of the strain sensor does not deform, and the feedback electrical signal remains stable at the strain reference value. However, when stress occurs, the strain gauge deforms, and the electrical signal fluctuates relative to the strain reference value. The greater the stress, the greater the fluctuation amplitude. It should be noted that the strain reference value is ɛ0, the acquired strain signal value is ɛ, and the difference between ɛ and ɛ0 is the fluctuation amplitude, i.e., Δɛ=|ɛ-ɛ0|. When Δɛ=0 or close to 0, it indicates that there is no stress on the actuator or the stress is low. The larger Δɛ is, the greater the feedback of the current stress change on the actuator. To further clarify, since the electrical signal is essentially a straight line when it is in a stable state during transmission, this straight line is usually referred to as the original baseline. There is a corresponding baseline signal value on the original baseline, which is represented as the strain reference value in this embodiment.

[0029] S200 monitors whether the stress change value of the actuator meets the collision triggering condition within a specified time based on real-time stress data. The stress change value is the fluctuation amplitude of the strain signal value relative to the strain reference value. In the real-time acquisition of stress data, a stress change value is acquired once per unit time. This unit time can be set to 0.01s, 0.1s, or 1s, depending on the specific situation. Therefore, the stress change value acquired within a specified time can be set to multiple continuously acquired strain signal values. For example, within a specified time T, a strain signal value is acquired once per unit time Δt, and the number of strain signal values ​​acquired within the specified time is N = T / Δt. N consecutive strain signal values ​​can be analyzed. As described in the previous embodiment, the fluctuation amplitude Δɛ can represent the stress value of the actuator at that moment. When the actuator experiences a collision, the stress it experiences will increase accordingly. Especially during the translation process driven by the driven component, when the actuator encounters an obstacle, the cantilever beam structure causes the actuator to undergo significant stress deformation, thus indicating whether a collision will occur.

[0030] Since stress can occur not only during collisions but also during the acceleration and deceleration of the pipetting arm actuator, both stress changes caused by collisions and other factors originate from a significant external force. This external force is formed by collision reaction forces, driving forces, etc. Therefore, we can determine whether the stress reaches the corresponding stress condition as a prerequisite, and then further analyze the collision phenomenon based on real-time stress data. This stress condition, as the first step in the collision analysis process, serves as the collision trigger condition, and is specifically manifested as follows: S210, determine whether the fluctuation amplitude of the strain signal values ​​acquired in multiple consecutive acquisitions relative to the strain reference value is not less than the first threshold. S220, if so, then determine that the stress change value of the actuator meets the collision triggering condition.

[0031] The first threshold is set based on the stress change value corresponding to the minimum stress generated by the collision, or it can be determined as the minimum stress change value corresponding to the threshold condition for determining that the actuator is in a stress change state. This first threshold can be set as a fixed value or dynamically set according to the current motion state of the actuator. In this embodiment, the first threshold is set as a dynamic threshold a, which is the strain signal values ​​ɛ1, ɛ2, ..., ɛ continuously acquired within a specified time T. n (n>1), where the fluctuation amplitude corresponding to the initial judgment signal ɛ1 of the collision triggering condition is greater than the first threshold a. That is, in the process of acquiring the strain signal value fed back by the strain sensor in real time and continuously, if the acquired strain signal value is greater than the first threshold, then the strain signal value is used as the initial judgment signal ɛ1 to activate the triggering state of the collision triggering condition, and the judgment continues for ɛ2,...,ɛ n The obtained stress variation values ​​Δɛ2,...,Δɛ n Is it greater than a? If so, does it have a stress change value Δɛ? i If the conditions are not met, it means that the collision triggering condition is not met. The stress change is not caused by contact with a collision force, but may only be due to accidental stress changes in the actuator during operation, or due to detection errors in the strain sensor during the feedback of strain signal values. In particular, when the actuator vibrates, the strain signal value emitted by the strain sensor may fluctuate around the strain reference value. The method of setting a specified number of stress change values ​​N consecutively within a specified time T, if all stress change values ​​Δɛ1, Δɛ2, ..., Δɛ n If all values ​​are greater than the first threshold 'a', it indicates that the current actuator is experiencing continuous stress during that time period. Excluding stress signal interference caused by vibration or other accidental factors, a collision may be present. In this embodiment, the specified quantity N can be set to 3. Since the collision occurs instantaneously, if the stress change value is greater than the first threshold for three consecutive unit time periods, it can be considered that a collision may exist.

[0032] It should be noted that the collision trigger condition is only a trigger condition for collision judgment and is not used as a direct judgment condition for collision. Because there may be stress value changes caused by non-collision forces such as driving force during the movement or rest of the actuator, it is necessary to conduct an in-depth analysis of the stress situation that causes this phenomenon, and make a reasonable judgment based on the characteristics of the collision in real-time stress data, such as the stress change situation and stress change process caused by the collision.

[0033] During the process of strain sensor detecting the actuator, inertial forces exist in the pipetting arm and actuator of the liquid transfer device during movement. For example, when the actuator is in an accelerating state, the strain signal value sensed by the strain sensor is the corresponding deformation of the strain gauge caused by the driving force on the actuator during acceleration. Similarly, when the actuator is in a stopped state after movement, the inertial force will cause corresponding stress deformation of the actuator, which will cause corresponding deformation of the strain gauge. In these situations, the strain signal value sensed by the strain sensor will deviate from the baseline value of the original baseline, thus requiring readjustment of the strain reference value.

[0034] In one embodiment, to eliminate the influence of the inertial forces of the pipetting arm, actuator, etc., of the liquid transfer device on the strain signal value sensed by the strain sensor during movement, the collision triggering condition further includes: S230, when the actuator is in an accelerated movement state, the strain reference value is corrected based on the inertial force of the actuator.

[0035] Under normal circumstances, since the mass of the pipette arm and actuator remains essentially constant, the inertial force generated by the actuator during movement usually does not change significantly. Therefore, when the inertial force of the actuator is considered in relation to the strain reference value during its movement, the correction amount for the strain reference value is usually a predictable constant. Based on this, the strain reference value is corrected according to the inertial force of the actuator, including: S231, the correction amount is determined based on the inertial force of the actuator, and the original strain reference value is increased by the correction amount to obtain the corrected strain reference value.

[0036] Since the original strain reference value is the baseline value in the feedback circuit when the strain sensor senses a change in strain force, and the stress effect of the inertial force generated by the actuator during movement can be considered fixed, the influence on the strain sensor during movement is that the change in strain signal value is added to the correction value. Specifically, assuming the original baseline value, i.e., the original strain reference value, is e0, then after adding the correction amount e1 caused by the inertial force of the actuator, the strain reference value used for the collision triggering condition is ɛ0 = e0 + e1, which can effectively eliminate the detection interference caused by the strain reference value during movement. In practical use, this correction amount is usually applied during the acceleration and deceleration process of the actuator. For example, during acceleration, the change in the strain reference value caused by the inertial force caused by the driving force, or the influence of the inertial force on the strain reference value during deceleration or even braking. Both acceleration and deceleration processes can be judged in real time by the driving state of the driving component. (See also...) Figure 1When the driving component is set as a drive motor, it will generate acceleration and deceleration signals to control the drive motor. These acceleration and deceleration signals can also be converted into conditional signals to determine whether the strain reference value needs to be corrected at that moment.

[0037] Furthermore, since other changing factors may exist during the movement of the actuator, these other changing factors can also be included in the scope of correction when correcting the strain reference value, which is also within the scope of this invention.

[0038] In another embodiment, the first threshold is set as a dynamic threshold obtained by correcting the allowable strain of the actuator based on the driving speed of the driving component and the amount of liquid absorbed by the actuator. This dynamic threshold takes into account the stress changes caused by the driving speed and the amount of liquid absorbed, so as to eliminate the influence of the driving speed and the amount of liquid absorbed on the strain signal value generated during the collision. The purpose of this dynamic threshold is to take into account the influence of collision factors. In conjunction with the aforementioned embodiments, the correction of the strain reference value is to eliminate the influence of inertial forces during the motion process of the actuator when no collision occurs, while the dynamic threshold is needed to avoid irreversible damage to the actuator, as the motion state and the amount of liquid absorbed will affect the collision force during the collision.

[0039] On the one hand, generally speaking, the faster the speed of the actuator, the greater the force before the collision, the greater the collision volume when the collision occurs, and the shorter the collision time. Therefore, a smaller threshold is needed to achieve emergency braking of the actuator. Specifically, the faster the speed, the shorter the instant of the collision. To trigger the emergency stop operation earlier, the first threshold can be lowered accordingly, thereby lowering the threshold for the collision triggering condition. For example, during the process of stress change at the beginning of the collision, the stress will continuously increase, and the corresponding strain signal value will continuously rise. Thus, by lowering the first threshold, the strain signal that meets the collision triggering condition can be earlier. For example, under normal circumstances, the collision triggering condition will be met at the 10th strain signal value. If there is a prerequisite of faster movement speed, the collision triggering condition may be triggered at the 8th strain signal value with a smaller first threshold, which can identify the occurrence of the collision phenomenon earlier and trigger the emergency stop in advance.

[0040] On the other hand, the more liquid absorbed by the actuator, the greater its mass will be compared to the unloaded state, and its strain signal value will differ from the normal unloaded condition. Therefore, the first threshold also needs to be adjusted to accurately identify the collision phenomenon and take emergency braking action. Specifically, as the amount of liquid absorbed inside the actuator increases, the stress on the actuator caused by the collision at the same speed also increases, while the collision process takes approximately the same amount of time. Therefore, the more liquid absorbed, the higher the actual signal value fed back by the strain sensor may be. Consequently, the first threshold needs to be lowered to make the collision triggering condition more closely match the actual situation, thus enabling dynamic adjustment. For example, under normal circumstances, at the same speed, the strain signal value that satisfies the collision triggering condition from the start of the collision to the occurrence of the collision process is the 20th strain signal, and the first threshold is set to a1. However, due to the presence of a large amount of liquid inside the actuator, the collision triggering condition may be triggered as early as the 18th strain signal before the collision begins, resulting in inaccurate collision identification. Therefore, the first threshold is adjusted to a lower threshold a2. It should be noted that, due to the increased weight of the actuator after absorbing liquid, stress changes that did not originally meet the triggering conditions may lead to false alarms if the first threshold is changed. Therefore, the first threshold needs to be dynamically adjusted according to the amount of liquid absorbed to ensure accurate judgment of collision phenomena.

[0041] Based on this, the first threshold can be determined using the following formula: a = p * [1 - f(v, q)] Where a is the first threshold, p is the allowable strain of the actuator, f(v,q) is the dynamic correction coefficient, v is the driving speed of the driving component, and q is the liquid absorption amount of the actuator.

[0042] In this formula, the allowable strain is the normal strain value of the actuator. It can be set as the normal strain threshold corresponding to the unloaded and stationary state, or it can be set as the ultimate strain value. When the ultimate strain value is exceeded, it indicates that the actuator has exceeded its current normal stress tolerance range. Therefore, the first threshold can be dynamically adjusted by multiplying the allowable strain by the corresponding coefficient. Specifically, when the dynamic correction coefficient is adjusted according to the velocity and liquid absorption, the dynamic correction coefficient f(v,q) is as follows: f(v,q)=k1*v+k2*q Where k1 is the velocity coefficient and k2 is the liquid absorption coefficient.

[0043] As can be seen from the dynamic correction coefficient formula, when the velocity is 0, it is only affected by the liquid absorption volume; when the liquid absorption volume is 0, it is only affected by the velocity. Therefore, when both the velocity and the liquid absorption volume are 0, the first threshold value is the allowable strain. Since there is no corresponding effect on the first threshold value, it is the allowable strain value at this time. In this embodiment, 0 ≤ f(v,q) < 1, and k1, k2 are both positive values. Their specific values ​​can be reasonably set according to the actual testing process.

[0044] Under this formula, it can be seen that the larger v is, the smaller its first threshold a is, which can achieve early braking of collision phenomena. When q is larger, the first threshold a is smaller, which can achieve adaptive adjustment of the stress change value corresponding to the strain force.

[0045] In another embodiment, due to different motion states of the actuator, abnormal working conditions related to motion may occur during the operation of the actuator. For example, when the operating speed is low, if a stepper motor is used as the driving component, the driving component may experience low-speed jerking during operation. Even in the case of a non-stepper motor, the actuator may experience slight vibrations, leading to misjudgments by the strain sensor. Alternatively, the driving speed of the driving component may exceed the maximum permissible speed limit during operation, potentially causing damage to the driving component or the actuator. Therefore, the collision detection method of this embodiment further includes: S201, when the drive component is in the first abnormal working condition, the first threshold is equal to the product of the allowable strain and the set coefficient; In the first abnormal operating condition, the driving speed of the drive component is in an abnormal state, which typically includes low speed and overspeed. Therefore, the conditions for determining its abnormal state are as follows: The driving speed is less than the first set speed or greater than the second set speed, where the second set speed is greater than the first set speed.

[0046] The first set speed is the low-speed threshold value for low-speed operation, and the second set speed is the threshold value for overspeed operation. Taking the current speed v as an example, the first set speed is v1, and the second set speed is v2. Therefore, when v < v1 or v > v2, the drive component is in a first abnormal operating condition. Under this abnormal operating condition, the first threshold is equal to the product of the allowable strain and the speed setting coefficient, i.e., a = c * p, where a is the first threshold, c is the speed setting coefficient, and p is the allowable strain. The setting values ​​of the speed setting coefficient are also different in the low-speed state and the overspeed state, corresponding to c1 and c2, respectively. S201a, when the driving speed is less than the first set speed, the first threshold is equal to the product of the allowable strain and the first set coefficient; S201b, when the driving speed is greater than the second set speed, the first threshold is equal to the product of the allowable strain and the second set coefficient.

[0047] Generally speaking, the collision time of the actuator caused by overspeed is relatively short, so the braking action of the actuator needs to be advanced when the collision occurs. In low-speed conditions, in order to avoid misjudgment caused by vibration, the first threshold needs to be increased. Therefore, c1 > c2, and both c1 and c2 are less than 1.

[0048] Furthermore, when the driving component is a stepper motor, in order to control the actuator to operate at a normal speed and prevent damage to the driving component or actuator caused by the driving component being in an abnormal state, the collision detection method also includes: S201c: When the driving speed is less than the first set speed, the driving component is controlled to enter the creeping state.

[0049] When v < v1, in order to avoid the driving component being stuck and affecting the misjudgment of the collision triggering condition, the mode of the driving component is adjusted to make it enter the creeping state to prevent the occurrence of small vibrations caused by low speed.

[0050] S201d: When the driving speed is greater than the second set speed, the driving speed of the control drive component is controlled not to exceed the second set speed.

[0051] If the driving speed of the driving component is greater than the second set speed v2, based on real-time driving data such as voltage, current, and power, it indicates that the driving component is in an overspeed state. Therefore, it is necessary to reduce the current driving speed of the driving component to reduce it to the normal speed condition.

[0052] S201e: When the duration of the drive speed being greater than the second set speed is greater than the set time, the drive action of the drive component is stopped.

[0053] From the moment the drive speed of the drive component is detected to be in an overspeed state, the drive speed is continuously monitored. If the duration exceeds the set time, it indicates that the current drive component may be in an abnormal drive state or have other problems such as loss of control. This triggers an emergency stop to stop the drive component's drive action in order to avoid further damage to the drive component or actuator.

[0054] In addition to the first abnormal operating condition caused by abnormal speed, there may also be a second abnormal operating condition caused by abnormal liquid absorption. The actuator has a liquid absorption range; for example, when the amount of liquid absorbed inside the actuator exceeds its range, the actuator in this abnormal condition will interfere with the collision triggering condition, thus requiring a corresponding dynamic adjustment of the first threshold. In this embodiment, the actuator of the liquid transfer device is equipped with a liquid volume detection mechanism for detecting the amount of liquid absorbed inside the actuator. This mechanism can be configured as a liquid level sensor or a weight sensor, or the liquid absorption action control can be used to accurately detect the amount of liquid absorbed, which has already been implemented in the prior art and will not be elaborated upon here. Accordingly, the collision triggering condition also includes: S202, when the actuator is in the second abnormal operating condition, correct the liquid absorption coefficient in the first threshold, or make the first threshold equal to the product of the allowable strain and the specified coefficient; In the second abnormal operating condition, the liquid absorption rate of the actuator is in an abnormal state. This abnormal state can be due to overload of the actuator or an abnormal negative pressure state. Taking the liquid absorption rate q as an example, and setting the liquid absorption range as Q, this abnormal state can be set with two conditions: one condition is q > Q, and the other condition is q < 0. Based on this, the determination condition for the abnormal liquid absorption rate of the actuator is as follows: The liquid intake exceeds the maximum intake range of the actuator or the liquid intake is negative.

[0055] In addition, since both exceeding the liquid absorption range and a negative liquid absorption value are abnormal conditions, the first threshold needs to be adjusted according to this second abnormal condition, specifically: S202a, When the liquid absorption rate exceeds the maximum absorption rate of the actuator, the liquid absorption coefficient is increased; That is, in the dynamic threshold adjustment formula of the first threshold in the aforementioned embodiment, the liquid absorption coefficient m is increased, thereby increasing the adjustment ratio compared to the normal adjustment process when the range is exceeded, enhancing the load correction weight, and thus making the collision triggering condition more accurate.

[0056] S202b, when the liquid absorption is negative, makes the first threshold equal to the product of the allowable strain and the specified coefficient.

[0057] When q < 0, there is an obvious abnormality. Therefore, during the process of moving the actuator, a = w * p is set, where w is a specified coefficient when the liquid absorption is negative, and 0 < w < 1, so that the first threshold can be adapted to the abnormal situation.

[0058] Specifically, after the second abnormal operating condition occurs, the collision detection method also includes: S202c, When the liquid intake exceeds the maximum intake range of the actuator, a message is displayed indicating that the liquid intake exceeds the limit; S202d: When the liquid absorption volume is negative, an operation abnormality is indicated, and the actuator is controlled to reset to the initial position.

[0059] In particular, steps S202c and S202d both indicate to the operator or user that the liquid transfer device has an abnormal condition, and in step S202d, the first threshold is set to a fixed value to detect collision phenomena that occur during the reset process.

[0060] Based on the above threshold optimization, the calibration process of the first threshold avoids interference from the liquid transfer function of the actuator. Through force transmission correction and dynamic update mechanism, it ensures the collision detection accuracy under all working conditions, which meets the dual requirements of reliability and functionality of the liquid transfer device.

[0061] S300, after the collision triggering conditions are met, determines the acceleration of stress change in the actuator based on real-time stress data within a specified time. S400: When the stress change acceleration is in an abnormal acceleration state, it is determined that a collision has occurred in the actuator.

[0062] After the collision triggering condition is met, the rate of stress change generated by the collision is significantly different from the rate of stress change caused by other factors. For example, during acceleration and deceleration, the stress gradually increases or decreases under the elastic reset of the actuator, without the instantaneous stress impact caused by the collision. Therefore, step S300, in determining the acceleration of stress change in the actuator, includes: S310, determine the rate of stress change of the actuator within a specified time period by using the strain signal value within that specified time period; Since the strain signal value reflects the magnitude of the stress detected by the strain sensor, the rate of stress change, representing the acceleration of stress change, can be confirmed through this strain signal value, specifically as the rate of stress change. When the acquired strain signal value that meets the collision triggering condition is ɛ m ,...,ɛ n When, the corresponding rate of change of stress can be set to L=dɛ / dt=(ɛ m -ɛ n ) / ((N-1)*△t) Where L is the rate of change of stress, ɛ m The strain signal value at the end of the specified time, ɛ n The value of the strain signal at the start of the specified time is N, the number of strain signal values ​​within the specified time is N, and Δt is the unit time for acquiring strain signal values.

[0063] Based on this, the magnitude of the stress change rate can be determined, and step S400 determines that the stress change acceleration is in an abnormal acceleration state, including: S410, when the rate of stress change is greater than the second threshold, it is determined that the acceleration of stress change is in an abnormal acceleration state.

[0064] If the second threshold is set to a fixed value b, then when L > b, it indicates that the stress change acceleration caused by the collision has been met. This confirms that the stress change acceleration is in an abnormal acceleration state, thereby identifying and confirming that a collision has occurred. The collision process is rapid, and accurate identification can be achieved instantaneously. Of course, the second threshold can also be set as a dynamic threshold based on other factors, which is also within the scope of this invention.

[0065] To implement the collision detection method of the first aspect of the present invention, the present invention also proposes a collision detection system 10 suitable for liquid transfer devices in a second aspect, see [reference]. Figure 3 ,include: The actuator 11 is used to control the drive component to move the actuator and to control the actuator to transfer liquid; The acquisition unit 12 is used to acquire real-time stress data of the actuator. The real-time stress data includes strain signal values ​​provided by strain sensors, and the strain signal values ​​are acquired once per unit time. Monitoring unit 13 is used to monitor whether the stress change value of the actuator meets the collision triggering condition within a specified time according to real-time stress data. The stress change value is the fluctuation amplitude of the strain signal value relative to the strain reference value. The processing unit 14 is used to determine the acceleration of stress change of the actuator based on real-time stress data within a specified time after the monitoring unit determines that the collision triggering condition is met, and to determine that the actuator has collided when the acceleration of stress change is in an abnormal acceleration state.

[0066] In a third aspect, embodiments of the present invention also provide a computer-readable storage medium, the computer-readable storage medium including a stored program, wherein, when the program is running, it controls the computer-readable storage medium to execute the collision detection method of the first aspect embodiment of the present invention within a device.

[0067] This invention also provides a computer device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When executed by the processor, the computer program implements the collision detection method described in the embodiments; to avoid repetition, these details are not elaborated here. Alternatively, when executed by the processor, the computer program implements the functions of each model / unit of the control device in the embodiments; to avoid repetition, these details are not elaborated here.

[0068] Computer devices include, but are not limited to, processors and memory. Those skilled in the art will understand that the above are merely examples of computer devices and do not constitute a limitation on computer devices. A computer device may include more or fewer components than illustrated, or a combination of certain components, or different components. For example, a computer device may also include input / output devices, network access devices, buses, etc.

[0069] The processor referred to can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0070] Memory can be an internal storage unit of a computer device, such as a hard drive or RAM. Memory can also be an external storage device of a computer device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, memory can include both internal and external storage units. Memory is used to store computer programs and other programs and data required by the computer device. Memory can also be used to temporarily store data that has been output or will be output.

[0071] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

[0072] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

[0073] Finally, it should be noted that the above description is merely the preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and simple substitutions to the technical solutions of the present invention using the disclosed methods and techniques without departing from the scope of the present invention; all of these variations fall within the protection scope of the present invention.

Claims

1. A collision detection method suitable for liquid transfer devices, characterized in that, The liquid transfer device includes a driving component and an actuator for liquid transfer. The driving component drives the actuator to move. A strain sensor is disposed on the actuator. The method includes: During the process of controlling the actuator to move to the target position, real-time stress data about the actuator is acquired, including strain signal values ​​provided by the strain sensor; Based on the real-time stress data, monitor whether the stress change value of the actuator meets the collision triggering condition within a specified time. The stress change value is the fluctuation amplitude of the strain signal value relative to the strain reference value. After the collision triggering condition is met, the acceleration of stress change in the actuator is determined based on the real-time stress data within the specified time period. When the stress change acceleration is in an abnormal acceleration state, it is determined that the actuator has collided. The strain signal value is acquired once per unit time, and the collision triggering condition includes: Determine whether the fluctuation amplitude of the strain signal values ​​acquired multiple times in succession relative to the strain reference value is not less than a first threshold. If so, it is determined that the stress change value of the actuator satisfies the collision triggering condition.

2. The method according to claim 1, characterized in that, The collision triggering conditions also include: When the actuator is in an accelerated movement state, the strain reference value is corrected based on the inertial force of the actuator; The step of correcting the strain reference value based on the inertial force of the actuator includes: The correction amount is determined based on the inertial force of the actuator, and the original strain reference value is increased by the correction amount to obtain the corrected strain reference value.

3. The method according to claim 1, characterized in that, The first threshold is set as a dynamic threshold obtained by correcting the allowable strain of the actuator based on the driving speed of the driving component and the liquid intake of the actuator.

4. The method according to claim 3, characterized in that, The first threshold is determined based on the following formula: a = p * [1 - f(v, q)] Where a is the first threshold, p is the allowable strain, f(v,q) is the dynamic correction coefficient, v is the driving speed of the driving component, and q is the liquid absorption amount of the actuator. In the dynamic correction coefficient f(v,q), f(v,q)=k1*v+k2*q Where k1 is the velocity coefficient and k2 is the liquid absorption coefficient.

5. The method according to claim 4, characterized in that, The collision triggering conditions also include: When the drive component is in a first abnormal operating condition, the first threshold is equal to the product of the allowable strain and the set coefficient; In the first abnormal operating condition, the driving speed of the driving component is in an abnormal state; The conditions for determining that the driving speed of the driving component is in an abnormal state are as follows: The driving speed is less than a first set speed or greater than a second set speed, wherein the second set speed is greater than the first set speed; When the driving component is in a first abnormal operating condition, the first threshold value is equal to the product of the allowable strain and the set coefficient, including: When the driving speed is less than the first set speed, the first threshold is equal to the product of the allowable strain and the first set coefficient; When the driving speed is greater than the second set speed, the first threshold is equal to the product of the allowable strain and the second set coefficient; Wherein, both the first setting coefficient and the second setting coefficient are less than 1, and the first setting coefficient is greater than the second setting coefficient.

6. The method according to claim 5, characterized in that, The driving component is a stepper motor, and the method further includes: When the driving speed is less than the first set speed, the driving component is controlled to enter a peristaltic state; When the driving speed is greater than the second set speed, the driving speed of the driving component is controlled to not exceed the second set speed; When the duration for which the driving speed is greater than the second set speed is greater than a set time, the driving action of the driving component is stopped.

7. The method according to claim 4, characterized in that, The collision triggering conditions also include: When the actuator is in the second abnormal operating condition, the liquid absorption coefficient in the first threshold is corrected, or the first threshold is made equal to the product of the allowable strain and the specified coefficient. In the second abnormal operating condition, the liquid absorption rate of the actuator is abnormal.

8. The method according to claim 7, characterized in that, The conditions for determining that the liquid intake of the actuator is in an abnormal state are as follows: The liquid absorption volume exceeds the maximum absorption range of the actuator or the liquid absorption volume is negative; When the actuator is in a second abnormal operating condition, correcting the liquid absorption coefficient in the first threshold, or making the first threshold equal to the product of the allowable strain and the specified coefficient, includes: When the amount of liquid drawn exceeds the maximum drawing range of the actuator, the liquid drawing coefficient is increased; When the liquid absorption is negative, the first threshold is made equal to the product of the allowable strain and the specified coefficient.

9. The method according to claim 1, characterized in that, Determining the acceleration of stress change in the actuator based on the real-time stress data within the specified time period includes: The rate of stress change of the actuator during the specified time period is determined by the strain signal value during the specified time period. Determining that the acceleration of stress change is in an abnormal acceleration state includes: When the rate of change of stress exceeds the second threshold, it is determined that the acceleration of stress change is in an abnormal acceleration state.

10. A collision detection system suitable for liquid transfer devices, characterized in that, The liquid transfer device includes a driving component and an actuator for liquid transfer. The driving component drives the actuator to move. A strain sensor is disposed on the actuator. The liquid transfer device includes: An execution unit is used to control the drive component to move the actuator and to control the actuator to transfer liquid; The acquisition unit is used to acquire real-time stress data of the actuator, the real-time stress data including strain signal values ​​provided by the strain sensor, the strain signal values ​​being acquired once per unit time. The monitoring unit is used to monitor whether the stress change value of the actuator meets the collision triggering condition within a specified time according to the real-time stress data, wherein the stress change value is the fluctuation amplitude of the strain signal value relative to the strain reference value. The processing unit is configured to, after the monitoring unit determines that the collision triggering condition is met, determine the stress change acceleration of the actuator based on the real-time stress data within the specified time period, and determine that the actuator has experienced a collision when the stress change acceleration is in an abnormal acceleration state. The collision triggering conditions include: Determine whether the fluctuation amplitude of the strain signal values ​​acquired multiple times in succession relative to the strain reference value is not less than a first threshold. If so, it is determined that the stress change value of the actuator satisfies the collision triggering condition.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the collision detection method suitable for a liquid transfer device as described in any one of claims 1 to 9.

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