A system and method for detecting intelligent resistance and retraction of a lifting table

Abstract

The present invention discloses an intelligent obstacle-retracting detection system and method for a lifting table. The system is mounted on the lifting table, and comprises a laser emitting assembly and a receiver arranged at the bottom of the tabletop of the lifting table. The laser emitting assembly and the receiver are arranged diagonally, and two groups of polygonal mirror assemblies are arranged between the laser emitting assembly and the receiver, respectively arranged along the length and width directions of the tabletop. The light emitter, the polygonal mirror assembly and the receiver form a square structure; a bubble level is arranged between the laser emitting assembly and the polygonal mirror assembly to detect whether the tabletop is tilted. The present invention realizes high-sensitivity, low-power consumption, wide application scenarios and high-precision obstacle-retracting detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of application of lifting tables, and in particular relates to an intelligent obstacle-encountering retraction detection system and method for lifting tables. Background Art

[0002] With the acceleration of the pace of modern life and work, lifting tables are becoming more and more popular because they can provide a healthier way of working. However, during the lifting process, if you encounter unknown obstacles, it may cause damage to the desktop or affect the user experience. The common method of encountering obstacles on the market is current detection, but because the current is affected by the load weight, operating altitude and ambient temperature, its accuracy is not high and the triggering is relatively unstable. At the same time, there are also detection methods using gratings on the market, but this optical detection method has high power consumption, high cost, and a narrow scope of application. Therefore, it is particularly important to develop a smart lifting table that automatically detects and responds to obstacles with low power consumption, low cost, and a wide range of applicable scenarios. Summary of the invention

[0003] In order to make up for the deficiencies of the prior art, the present invention aims to provide an intelligent obstacle-encountering retraction detection system and method for a lift table, so as to solve the problems of high power consumption and high cost in the existing processing methods of lift tables when dealing with obstacles, and the narrow scope of application of the existing methods.

[0004] To solve the technical problem of the present invention, the following technical solutions can be used:

[0005] On the one hand, an intelligent obstacle-encountering retraction detection system for a lifting table is provided, which is installed on the lifting table and includes a laser emitting assembly and a receiver arranged at the bottom of the desktop of the lifting table. The laser emitting assembly and the receiver are arranged diagonally, and two groups of polygonal prism assemblies are arranged between the laser emitting assembly and the receiver, respectively arranged along the length and width directions of the desktop. The light emitter, the polygonal prism assembly and the receiver form a square structure; a bubble level is arranged between the laser emitting assembly and the polygonal prism assembly for detecting whether the desktop is tilted.

[0006] Furthermore, the laser emitting assembly includes two laser emitters which are perpendicular to each other, and the two laser emitters are respectively arranged along the length and width of the desktop.

[0007] Furthermore, the polygonal mirror assembly includes one or more polygonal mirrors for magnifying the passing laser path.

[0008] Furthermore, the bubble level includes a glass tube filled with liquid, and a bubble is provided in the liquid. When the table top of the lifting table is kept horizontal, gravity acts evenly on the liquid and the bubble in the glass tube, so that the bubble remains in the center position; if the table top of the lifting table is tilted, the bubble will be affected by uneven gravity, thereby deviating from the center position of the liquid.

[0009] Furthermore, when the desktop of the lifting table is in a horizontal state, the laser emitted by the laser emitting assembly, the bubble in the bubble level, and the receiver are on the same horizontal line, ensuring that the receiver can normally receive the laser signal.

[0010] Furthermore, it also includes a motor and a controller, wherein the controller is used to receive and process signals, and includes a current acquisition circuit, a processing unit and a control unit.

[0011] The current acquisition circuit is used to detect the real-time current of the motor of the lifting table during movement;

[0012] The processing unit is used to filter and reduce noise on the signal data received by the receiver to obtain a stable value;

[0013] The control unit is responsible for processing the signal sent by the receiver and the current fluctuation value of the motor, and judging whether an obstacle is encountered according to a preset algorithm; once it is confirmed that an obstacle is encountered, the control unit will send an instruction to the motor of the lifting table to stop moving or move in the opposite direction to avoid a collision.

[0014] Furthermore, the preset algorithm is: within the total time of 500ms, the current fluctuation is sampled every 100ms and exceeds the set value, for a total of 5 samples. If the 5 current fluctuations all exceed the set value, it is judged as encountering an obstacle, and the control unit performs a fallback operation; if the fluctuation value is less than the set threshold, it means that it is in normal operation at this time.

[0015] On the other hand, a detection method based on the above-mentioned intelligent obstacle-encountering retraction detection system for a lifting table is provided, and the steps include:

[0016] Step 1: Calibrate the laser angle emitted by the laser emitting component so that the emitted laser and the bubble of the bubble level are on the same horizontal line. When the desktop of the lifting table is in a horizontal state, the receiver can receive the laser signal normally.

[0017] Step 2: When the desktop is in a horizontal state, the laser emitting component emits a laser beam along the length and width of the desktop. The laser beam passes through the bubble of the bubble level and the prism component in turn before reaching the receiver.

[0018] Step 3: When the lifting table starts to run, the real-time current fluctuation value of the motor and the position of the laser light received by the receiver are detected;

[0019] Step 4: The processing unit of the controller filters and reduces noise of the current fluctuation value through a first-order Kalman filter to obtain a relatively stable value;

[0020] Step 5: determine whether the current fluctuation value exceeds the set threshold value. If so, it is determined to be a resistance, and the control unit controls the motor to perform a back-off operation;

[0021] Step 6, determine whether the signal offset received by the receiver is within the threshold range. If the receiver does not receive a signal or the signal offset is greater than the threshold, it is determined to be obstructed, and the control unit controls the motor to perform a back-off operation; if the receiver receives a signal and the signal offset is within the threshold range, it is determined to be operating normally, and returns to step 3 until it is determined to be obstructed or the lifting table reaches the specified position.

[0022] Furthermore, when an obstruction state is identified, the motor stops immediately within 1 second and runs in the opposite direction for a protection distance of (40±10) mm.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) High sensitivity: The present invention adds optical detection on the basis of current detection, which avoids the influence of load weight, operating altitude and ambient temperature on current to a certain extent during operation, resulting in insensitive obstruction judgment or false triggering. The obstruction protection can also be triggered by optical detection.

[0025] (2) Low power consumption: For grating optical technology, the existing technology requires the installation of multiple laser transmitters and receivers, and the laser transmitters and receivers correspond one to one, which consumes a lot of power in actual use; while the present invention only requires two laser transmitters and one receiver, and the power consumption is lower than that of the existing technology.

[0026] (3) Wide application scenarios: The present invention takes into account a variety of obstruction environments, such as an object approaching the bottom of the table during the operation of the lifting table; the table top being bent by an obstacle; and the table top being tilted by an obstacle.

[0027] (4) High precision: The present invention uses optical detection to amplify the tiny deformation of the desktop when it is subjected to resistance, and can detect tiny displacement changes, thereby improving the accuracy of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the detection system of the present invention;

[0029] Figure 2 Flow chart of the detection method of the present invention.

[0030] In the figure: 1-laser transmitting assembly, 2-bubble level, 3-polygonal mirror assembly, 4-receiver. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment provides an intelligent obstacle-encountering retraction detection system for a lifting table, which is assembled on the lifting table and includes a laser emitting component 1 and a receiver 4 arranged at the bottom of the desktop of the lifting table. The laser emitting component 1 and the receiver 4 are arranged diagonally, and two groups of polygonal prism components 3 are arranged between the laser emitting component 1 and the receiver 4, which are arranged along the length and width directions of the desktop respectively. The light emitter 1, the polygonal prism component 3 and the receiver 4 form a square structure; a bubble level 2 is arranged between the laser emitting component 1 and the polygonal prism component 3 for detecting whether the desktop is tilted.

[0034] In this embodiment, the laser emitting assembly 1 is used to emit a stable infrared laser, and includes two laser emitters perpendicular to each other, and the two laser emitters are respectively arranged along the length and width of the desktop. The prism assembly 3 is used to magnify the laser path passing through, and even a slight deviation can be detected. The prism assembly 3 includes one or more prisms, which are used to magnify the laser path passing through. The bubble level 2 is arranged on the propagation path of the infrared laser emitted by the laser emitting assembly 1, so that the laser just passes through the bubble therein, and is used to detect whether the desktop is tilted. The bubble level 2 includes a glass tube, which is filled with liquid, and a bubble is provided in the liquid. When the desktop of the lifting table is kept in a horizontal state, gravity acts evenly on the liquid and the bubble in the glass tube, so that the bubble remains in the center position; if the desktop of the lifting table is tilted, the bubble will be affected by uneven gravity, thereby deviating from the center position of the liquid.

[0035] It can be understood that when the desktop of the lifting table is in a horizontal state, the laser emitted by the laser emitting component 1, the bubble in the bubble level 2, and the receiver 4 are on the same horizontal line, ensuring that the receiver 4 can normally receive the laser signal.

[0036] The detection system of the present application also includes a motor and a controller. The controller is used to receive and process signals, including a current acquisition circuit, a processing unit and a control unit. The current acquisition circuit is used to detect the real-time current of the motor of the lifting table during movement; the processing unit is used to filter and reduce noise on the signal data received by the receiver 4 to obtain a stable value; the control unit is responsible for processing the signal sent by the receiver 4 and the current fluctuation value of the current motor, and judges whether an obstacle is encountered according to a preset algorithm (judging the current fluctuation value at this time, such as within a total time of 500ms, sampling the current current fluctuation every 100ms to exceed the set value, a total of 5 samples, if the 5 current fluctuations all exceed the set value, it is judged as encountering an obstacle); once it is confirmed that an obstacle is encountered, the control unit will send an instruction to the motor of the lifting table to stop moving or move in the opposite direction to avoid collision.

[0037] The receiver 4 is used to capture the amplified laser signal. When the desktop is slightly bent, the receiver 4 can detect the change in the laser position. The system of the present application extends the path of laser propagation between the laser emitting component 1 and the receiver 4. Even when a slightly changed path is transmitted to the receiver 4, the slight change will be amplified.

[0038] If there are no obstacles in the propagation path of the laser and the desktop is not tilted by external force, the receiver 4 will receive a nearly constant signal; on the contrary, if there is an obstacle that causes the desktop to be slightly bent or an external force causes it to tilt to one side, the bubble in the bubble level will move, causing the laser to enter the liquid instead of the bubble. Since the refractive index of light propagating in different media is different, the propagation path of the laser will change. When the optical path changes, the position of the signal received by the receiver will change.

[0039] Example 2

[0040] like Figure 2 As shown, this embodiment provides a detection method of the intelligent obstacle-encountering retraction detection system for a lift table based on Embodiment 1, and the steps include:

[0041] Step 1: calibrate the laser angle emitted by the laser emitting component 1 so that the emitted laser and the bubble of the bubble level 2 are on the same horizontal line. When the desktop of the lifting table is in a horizontal state, the receiver 4 can receive the laser signal normally.

[0042] Step 2: When the desktop is in a horizontal state, the laser emitting assembly 1 emits a laser beam along the length and width of the desktop. The laser passes through the bubble of the bubble level 2 and the prism assembly 3 in turn and then reaches the receiver 4.

[0043] Step 3: When the lifting table starts to run (rise or fall), the real-time current fluctuation value of the motor and the position of the laser light received by the receiver 4 are detected.

[0044] Step 4: The processing unit of the controller filters and reduces noise on the current fluctuation value through a first-order Kalman filter to obtain a relatively stable value.

[0045] The specific calculation process is:

[0046] Prediction covariance equation: System estimation covariance at time k = system covariance at time k-1 + process noise covariance, that is:

[0047] kfp->P=kfp->L_P+kfp->Q;

[0048] Kalman gain equation: Kalman gain = system estimation covariance at time k / (system estimation covariance at time k + observation noise covariance), that is:

[0049] kfp->K=kfp->P / (kfp->P+kfp->R);

[0050] Update the optimal value equation: The optimal value of the state variable at time k = the predicted value of the state variable + Kalman gain * (measured value - predicted value of the state variable), that is:

[0051] kfp->X=kfp->K+kfp->K*(real-time sampling current value-kfp->X); the predicted value this time is the output value of the previous time.

[0052] Update the covariance equation: The system covariance is paid to kfp->L_P for the next calculation, that is:

[0053] kfp->L_P=(1-kfp->K)*kfp->P.

[0054] In a specific embodiment, first, the coefficient value of the Kalman filter is set, the system covariance L_P at the previous moment is 1, the system covariance P at the current moment is 0, the process covariance Q is 0.001, the observation noise covariance R is 0.02, the Kalman gain value K is 0, and the optimal value X at the current moment is 0; then, the real-time sampled current value is substituted into the formula to obtain a stable current value.

[0055] During the normal operation of the lifting table, the current fluctuation of the motor is very small, but if it is suddenly hindered by a larger force, the current of the motor will increase to increase the torque of the motor to counteract the resistance.

[0056] Step 5: Determine whether the current fluctuation value exceeds the set threshold value. If so, it is determined that there is an obstacle, and the control unit controls the motor to perform a back-off operation.

[0057] The range of the current fluctuation threshold is determined by the rising current of the different lifting tables and the currently set resistance sensitivity. It will be set directly in the program and must meet the following conditions:

[0058] 1) Current current > reference current * (coefficient 1 + rebound sensitivity) / 10

[0059] 2)(Current current / Coefficient 2)*(Current increase within 250ms)>(Base current*(Coefficient 3+Rebound sensitivity)).

[0060] For example: within a total time of 500ms, the current fluctuation is sampled every 100ms and exceeds the set value, for a total of 5 samples. If the current fluctuations exceed the set value for 5 consecutive times, it is judged as encountering resistance, and the control unit performs a fallback operation; if the fluctuation value is less than the set threshold, it means that it is in normal operation at this time.

[0061] Step 6, determine whether the signal offset received by the receiver 4 is within the threshold range. If the receiver 4 does not receive the signal or the signal offset is greater than the threshold of the laser receiving range, it is determined that an obstruction is encountered, and the control unit controls the motor to perform a retract operation; if the receiver 4 receives the signal and the signal offset is within the threshold range, it is determined to be in normal operation, and returns to step 3 until it is determined that an obstruction is encountered or the lifting table reaches the specified position.

[0062] The receiver 4 has a high-precision receiving dot matrix, which can identify the position of the laser entering the dot matrix. The threshold range of the receiving dot matrix can be set by the host computer software. When the laser entry position is within the set range, it is not judged as encountering an obstruction. If the laser entry position exceeds the set range, it is judged as encountering an obstruction.

[0063] There are many possible situations that may lead to obstruction: first, an obstacle blocks the propagation path of the laser, and the obstruction can be judged in advance; second, the desktop is squeezed by the obstacle and the bending deformation is greater than the threshold; third, the desktop is squeezed by the obstacle and tilted. When it is identified as an obstruction state, the motor stops within 1 second and runs in the opposite direction for a protection distance of (40±10) mm.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An intelligent obstacle-encountering retraction detection system for a lifting table, mounted on a lifting table, characterized in that: The lifting table comprises a laser emitting assembly (1) and a receiver (4) arranged at the bottom of the desktop of the lifting table, wherein the laser emitting assembly (1) and the receiver (4) are arranged diagonally, and two groups of polygonal mirror assemblies (3) are arranged between the laser emitting assembly (1) and the receiver (4), respectively arranged along the length and width directions of the desktop, and the light emitter (1), the polygonal mirror assembly (3) and the receiver (4) form a square structure; and a bubble level (2) is arranged between the laser emitting assembly (1) and the polygonal mirror assembly (3) for detecting whether the desktop is tilted.

2. According to claim 1, the intelligent obstacle-encountering retraction detection system for a lifting table is characterized in that: The laser emitting assembly (1) comprises two laser emitters which are perpendicular to each other, and the two laser emitters are respectively arranged along the length and width of the desktop.

3. The intelligent obstacle-encountering retraction detection system for a lifting table according to claim 1 is characterized in that: The polygonal mirror assembly (3) comprises one or more polygonal mirrors for magnifying the laser path passing through.

4. The intelligent obstacle-encountering retraction detection system for a lifting table according to claim 1 is characterized in that: The bubble level (2) comprises a glass tube filled with liquid and provided with a bubble in the liquid. When the tabletop of the lifting table is kept horizontal, gravity acts evenly on the liquid and the bubble in the glass tube, so that the bubble is kept at the center position. If the tabletop of the lifting table is tilted, the bubble will be affected by uneven gravity, so that it deviates from the center position of the liquid.

5. The intelligent obstacle-encountering retraction detection system for a lifting table according to claim 4 is characterized in that: When the tabletop of the lifting table is in a horizontal state, the laser emitted by the laser emitting component (1), the bubble in the bubble level (2), and the receiver (4) are on the same horizontal line, ensuring that the receiver (4) can normally receive the laser signal.

6. The intelligent obstacle-encountering retraction detection system for a lift table according to any one of claims 1 to 5, characterized in that: It also includes a motor and a controller, wherein the controller is used to receive and process signals, and includes a current acquisition circuit, a processing unit and a control unit. The current acquisition circuit is used to detect the real-time current of the motor of the lifting table during movement; The processing unit is used to filter and perform noise reduction processing on the signal data received by the receiver (4) to obtain a stable value; The control unit is responsible for processing the signal sent by the receiver (4) and the current fluctuation value of the motor, and judging whether an obstacle is encountered according to a preset algorithm; Once it is confirmed that there is an obstacle, the control unit will send a command to the motor of the lifting table to stop moving or move in the opposite direction to avoid a collision.

7. The intelligent obstacle-encountering retraction detection system for a lifting table according to claim 6, characterized in that: The preset algorithm is: within the total time of 500ms, the current fluctuation is sampled every 100ms and exceeds the set value, for a total of 5 samples. If the 5 current fluctuations all exceed the set value, it is judged as encountering resistance, and the control unit performs a fallback operation; if the fluctuation value is less than the set threshold, it means that it is in normal operation at this time.

8. A detection method based on the intelligent obstacle-encountering retraction detection system for a lifting table according to claim 6 or 7, characterized in that: The steps include: Step 1, calibrate the laser angle emitted by the laser emitting component (1) so that the emitted laser and the bubble of the bubble level (2) are on the same horizontal line, and when the tabletop of the lifting table is in a horizontal state, the receiver (4) can normally receive the laser signal; Step 2: When the desktop is in a horizontal state, the laser emitting assembly (1) emits a laser beam along the length and width of the desktop, and the laser beam passes through the bubble of the bubble level (2), the prism assembly (3) and reaches the receiver (4); Step 3: When the lifting table starts to operate, the real-time current fluctuation value of the motor and the position of the laser light received by the receiver (4) are detected; Step 4: The processing unit of the controller filters and reduces noise of the current fluctuation value through a first-order Kalman filter to obtain a relatively stable value; Step 5: determine whether the current fluctuation value exceeds the set threshold value. If so, it is determined to be a resistance, and the control unit controls the motor to perform a back-off operation; Step 6, determine whether the signal offset received by the receiver (4) is within a threshold range. If the receiver (4) does not receive a signal or the signal offset is greater than the threshold, it is determined to be obstructed, and the control unit controls the motor to perform a retracting operation; if the receiver (4) receives a signal and the signal offset is within the threshold range, it is determined to be in normal operation, and returns to step 3 until it is determined to be obstructed or the lifting table reaches the specified position.

9. The detection method according to claim 8, characterized in that: When it is identified as encountering an obstruction state, the motor stops immediately within 1 second and runs in the opposite direction for a protection distance of (40±10) mm.

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