Tension control method and system

Abstract

The invention discloses a tension control method and system, and the method and system are characterized in that a master motor PID controller and a slave motor PID controller respond to a tension error signal at different time intervals, generate control signals of a master motor and a slave motor according to the tension error signal, and control the output tension of the master motor and a slave node. According to the method and the system, the problem that the tension cannot be accurately controlled due to fluctuation of the tension on the cable car rope and the speed on the cable under the application scene that the tension in a large range needs to be controlled can be solved, secondly, the response speed to the tension error is further improved, and the control accuracy of the tension error is improved. And the generated tension error can be adjusted in time.

Description

Technical Field

[0001] The present invention relates to a tension control method and system, and realizes precise tension control in application scenarios with a large tension control range. Background Art

[0002] A tension simulation device is a test equipment specifically used to test the load handling performance of a winch or the mechanical properties of a cable. In terms of structure, the tension simulation device is very similar to an ordinary tension winch, so it can also realize the normal load handling function of an ordinary winch.

[0003] The tension simulation device is often applied in some ship industries and some simulated load test fields, and is mainly used as a simulated load to test a winch or a cable array, and it is necessary to ensure that the tension on the cable follows the instruction during the working process.

[0004] In fact, it can also be applied to the tension control of a raw foil roll. For example, a raw foil machine winding tension control system is disclosed on the Chinese Patent Network, and its application number is: 201911128237.7. The technical solution of this patent is mainly: determining a speed reference value according to the absolute difference between the actual winding tension and the preset tension, and determining the winding speed according to the absolute difference between the speed reference value and the actual speed, so as to achieve the effect of controlling the tension.

[0005] However, in some application scenarios, since the tension range required to be simulated by the tension simulation device is large, and the maximum tension is about 20 times the minimum tension, all components need to be designed according to the maximum tension, which significantly increases the overall mass, moment of inertia, and friction of the tension simulation device, resulting in a slow response of the entire tension simulation device.

[0006] At the same time, there are two obvious disturbances in the tension simulation device, namely the cable speed and the tension on the storage cable car cable.

[0007] For the tension on the storage cable car cable, during the operation process, since the length of the cable stored on the storage cable car changes, the moment of inertia of the storage cable car changes. At the same time, since the damping ratio of the storage cable car is small, when the moment of inertia of the storage cable car changes, the tension on the cable is likely to fluctuate. And the damping ratio of the tension reducing device is also small, so the fluctuation will cause the fluctuation of the controlled tension, thereby reducing the steady-state control accuracy.

[0008] Currently, the control instructions of two servo motors are both given by a single PID controller. For a non-linear, time-varying, multi-disturbance system, it is generally very difficult for a single PID controller to have good control performance. In the tension simulation device, the moment of inertia of the storage winch and the parameters of the servo motor will change greatly during the operation of the device, and there are two disturbances, namely the cable speed and the tension on the storage cable car cable, making it difficult to achieve high-precision tension control. Summary of the Invention

[0009] The object of the present invention is to provide a tension control method to solve the problem of reduced tension control accuracy caused by cable disturbances and tension disturbances on the storage cable car rope in application scenarios with a large tension control range, and to improve the accuracy of tension control.

[0010] Another object of the present invention is to provide a tension control system that combines the characteristics of the main motor and the slave motor to achieve fine control of tension in application scenarios with a large tension control range.

[0011] Another object of the present invention is to provide a tension control system that adaptively identifies the credibility of the tension feedback value through the tension acquisition module in the tension control system.

[0012] To achieve the above object, the present invention provides a tension control method. The method steps include: reading the values of a number of tension sensors in real time, calling the error signal acquisition module to obtain the tension error signal; the main motor PID controller and the slave motor PID controller respectively generate control signals for the main motor and the slave motor in response to the tension error signal at different time intervals; the main motor PID controller and the slave motor PID controller control the tension output of the main motor and the slave motor through the control signals. Make full use of the small motor for precise tension control and the large motor for load bearing to achieve higher-precision tension control.

[0013] Further, the time interval for the main motor PID controller to respond to the tension error signal is greater than the time interval for the slave motor PID controller to respond to the tension error signal.

[0014] Further, the time interval for the main motor PID controller to respond to the tension error signal is an integer multiple of the time interval for the slave motor PID controller to respond to the tension error signal.

[0015] Further, the time interval for the main motor controller to respond to the tension error signal is at least four times the time interval for the slave motor PID controller to respond to the tension control signal.

[0016] Further, if the standard deviation of the value set of the tension sensors is not less than the stability threshold, the process of the method is ended; if the standard deviation of the value set of the tension sensors is less than the stability threshold, the average value of all the values of the tension sensors is taken as the tension control feedback value.

[0017] Further, if the absolute difference between the values of the tension sensors is not less than the difference threshold, the process of the method ends; if the absolute difference between the values of the tension sensors is less than the difference threshold, the average value of all the values of the tension sensors is taken as the tension control feedback value.

[0018] The present invention provides a tension control system. The system executes any of the above methods, and the system includes: a main control module, including: a main motor PID controller and a main motor; the main motor PID controller generates a control signal for the main motor in response to a tension error signal at a first time interval; a slave control module, including: a slave motor PID controller and a slave motor; the slave motor PID controller generates a control signal for the slave motor in response to the tension error signal at a second time interval.

[0019] Further, the system includes: a tension acquisition module, and the tension acquisition module includes: a sensor reading judge and a plurality of tension sensors; the number of the tension sensors is at least two, and the tension sensors acquire the actual output tension of the system and output values; the sensor reading judge acquires the values of the plurality of tension sensors and obtains the tension feedback value of the system according to the values.

[0020] Further, the system includes: an error signal acquisition module, and the error signal acquisition module acquires the tension feedback value of the sensor reading judge, acquires the difference between the desired tension and the tension feedback value in real time, generates the tension error signal, and transmits the tension error signal to the main motor PID controller or the slave motor PID controller.

[0021] Further, the first time interval is greater than the second time interval.

[0022] The beneficial effect of the present invention is that through reasonable selection of PID parameters and selection of the control frequencies of the large motor and the small motor, the large torque characteristic of the large motor is utilized for load bearing, and the fine control of the small motor is utilized to overcome the disturbance caused by the changes of parameters such as the cable speed and the storage cable car during the normal operation of the mechanism, so as to meet the higher control accuracy requirements. Description of the Drawings

[0023] Figure 1 It is a flowchart of a method related to the present invention.

[0024] Figure 2 It is a desired tension curve graph.

[0025] Figure 3 It is a framework diagram of a system related to the present invention.

[0026] Figure 4This invention relates to a structural diagram of a system.

[0027] Figure 5 This invention relates to a flowchart of a method.

[0028] Figure 6 This invention relates to a framework diagram of a system.

[0029] Figure 7 This invention relates to a structural diagram of a system.

[0030] Figure 8 It is a process schematic diagram of a tension simulation. Detailed implementation manners

[0031] Example 1. This example discloses a specific implementation process of the method related to this invention. Refer to Figure 1 .

[0032] In this example, the specific implementation process of the method is as described below.

[0033] Read the values of two tension sensors in real time, call the error signal acquisition module to obtain the tension error signal.

[0034] When reading the values of two tension sensors, it is necessary to obtain the absolute difference between the values of the two tension sensors. According to the magnitude relationship between this absolute difference and the difference threshold, determine the subsequent operations.

[0035] Specifically: If this absolute difference is not less than the difference threshold, it means that the values of at least one tension sensor are not credible, resulting in an untrustworthy tension feedback value, and the entire tension control process ends; if this absolute value is less than the difference threshold, it means that the values of the tension sensors are all credible, and take the average value of the values of the two tension sensors as the tension feedback value.

[0036] After obtaining the tension feedback value, obtain the value of the expected tension at this moment, subtract the tension feedback value from the expected tension value to obtain the tension error between the expected tension value and the tension feedback value, and generate a tension error signal at this moment according to this tension error.

[0037] It should be noted that the main motor PID controller and the slave motor PID controller store the tension error values at each moment.

[0038] The main motor PID controller and the slave motor PID controller respond to the tension error signal at different time intervals and generate control signals according to the tension error signal.

[0039] The time interval for the main motor PID controller to respond to the tension error signal is different from the time interval for the slave motor PID controller to respond to the tension error signal.

[0040] Specifically: the main motor PID controller and the slave motor PID controller obtain the running time.

[0041] For the main motor PID controller, if the value of the running time divided by the time interval in which the main motor PID controller responds to the tension error signal is an integer, then the main motor PID controller responds to the tension error signal and generates a main motor control signal, thereby updating the main motor control signal; if the value of the running time divided by the time interval in which the main motor PID controller responds to the tension error signal is not an integer, then the main motor PID controller does not respond to the tension error signal, does not generate a main motor control signal, and keeps the original main motor control signal unchanged.

[0042] For the slave motor PID controller, if the value of the running time divided by the time interval in which the slave motor PID controller responds to the tension error signal is an integer, then the slave motor PID controller responds to the tension error signal and generates a slave motor control signal, thereby updating the slave motor control signal; if the value of the running time divided by the time interval in which the slave motor PID controller responds to the tension error signal is not an integer, then the slave motor PID controller does not respond to the tension error signal, does not generate a slave motor control signal, and keeps the original slave motor control signal unchanged.

[0043] Or, when the slave motor PID controller generates a certain number of slave motor control signals, the main motor generates a control signal according to the tension error signal.

[0044] If the main motor PID controller and the slave motor PID controller respond to the tension error signal at the same time, the main motor PID controller preferentially generates a control signal until the tension error signal is updated, obtains the tension error signal, and the slave motor PID controller generates a control signal for the slave motor controller according to the tension error signal.

[0045] The output tension of the main motor should be greater than that of the slave motor. Therefore, the main motor plays a bearing role, with a larger output torque, lower torque control accuracy, and slower response. While the slave motor plays a role in adjusting the tension, with a smaller output torque, higher torque control accuracy, and faster response.

[0046] Therefore, in order to achieve the purpose of precise tension control, the time interval in which the main motor PID controller responds to the tension error signal should be greater than the time interval in which the slave motor PID controller responds to the tension error signal, and moreover, the time interval in which the main motor PID controller responds to the tension error signal is an integer multiple of the time interval in which the slave motor PID controller responds to the tension error signal; the time interval in which the main motor PID controller responds to the tension error signal is at least four times the time interval in which the slave motor PID responds to the tension error signal.

[0047] The main motor PID controller and the slave motor PID controller generate a control signal: the output torque of the main motor or the slave motor at this moment.

[0048] The process for the main motor PID controller and the slave motor PID controller to generate the control signal is: obtaining the historical cumulative tension error, the tension error at this moment, and the tension error at the previous moment.

[0049] Based on the above data, calculate the output torques of the main motor and the slave motor at this moment. The expression of this torque is: where, ΔF t is the tension error value; K p , K i and K D are adjustment coefficients; u(t) is the motor torque at time t.

[0050] The adjustment coefficients of the main motor PID controller are different from those of the slave motor PID controller.

[0051] Converted to the discrete form:

[0052] By controlling the torque output of the main motor or the slave motor, the output tensions of the main motor and the slave motor are thus controlled.

[0053] After the main motor PID controller and the slave motor PID controller generate the control signal, the main motor PID controller and the slave motor PID controller control the output tensions of the main motor and the slave motor through control instructions.

[0054] To further illustrate the technical solution of this embodiment, through a specific example, the technical solution of this embodiment is further described.

[0055] Refer to Figure 2 , in Figure 2 , the abscissa represents time, and the ordinate represents the expected output tensions at each moment.

[0056] In this example, the number of main motors and main motor PID controllers is 1; the number of slave motors and slave motor PID controllers is 1; the number of tension sensors is 1.

[0057] At the start of the tension control process, both the main motor PID controller and the slave motor PID controller are run simultaneously. In this example, the time interval for the main motor PID controller to respond to the tension error signal is 4 ms, and the time interval for the slave motor PID controller to respond to the tension error signal is 1 ms. Also, the desired tension output magnitude at the initial moment is 500 N, the desired output tension at the final moment is 10 kN, and the desired output tension increases linearly with the increase of the time period, with the maximum moment being 40 ms.

[0058] When the current moment is 0 ms, 4 ms, 8 ms, 12 ms, 16 ms or 20 ms, the running times of the main motor PID controller and the slave motor PID controller are 0 ms, 4 ms, 8 ms, 12 ms, 16 ms or 20 ms.

[0059] The values obtained by dividing the above running times by the response time interval of the main motor PID are all 0, which are integers. Therefore, at 0 ms, 4 ms, 8 ms, 12 ms, 16 ms or 20 ms, the main motor PID controller responds to the tension error signal.

[0060] The values obtained by dividing the above running times by the response time interval of the slave motor PID are all 0, which are integers. Therefore, at 0 ms, 4 ms, 8 ms, 12 ms, 16 ms or 20 ms, the slave motor PID controller responds to the tension error signal.

[0061] At 0 ms, 4 ms, 8 ms, 12 ms, 16 ms or 20 ms, the main motor PID controller and the slave motor PID controller respectively generate control signals to control the tension output of the main motor and the slave motor, so that the resultant force output by the main motor and the slave motor approaches the desired tension.

[0062] And at this moment, the main motor preferentially generates the main motor control signal to control the output tension of the main motor. After the main motor outputs the tension, the tension error signal is obtained. When the current moment is 1 ms, 2 ms, 3 ms, 5 ms, 6 ms, 7 ms, 9 ms, 10 ms, 11 ms, 13 ms, 14 ms, 15 ms, 17 ms, 18 ms or 19 ms, the running times of the main motor PID controller and the slave motor PID controller are 1 ms, 2 ms, 3 ms, 5 ms, 6 ms, 7 ms, 9 ms, 10 ms, 11 ms, 13 ms, 14 ms, 15 ms, 17 ms, 18 ms or 19 ms respectively.

[0063] The values obtained by dividing the above-mentioned running time by the time intervals of the main motor PID are not integers. Therefore, at the moments of 1 ms, 2 ms, 3 ms, 5 ms, 6 ms, 7 ms, 9 ms, 10 ms, 11 ms, 13 ms, 14 ms, 15 ms, 17 ms, 18 ms, or 19 ms, the main motor PID controller does not respond to the tension error signal, does not generate a main motor control signal, and keeps the original main motor control signal unchanged, thereby keeping the tension output by the main motor unchanged.

[0064] The values obtained by dividing the above-mentioned running time by the time intervals of the slave motor PID are all integers. Therefore, at the moments of 1 ms, 2 ms, 3 ms, 5 ms, 6 ms, 7 ms, 9 ms, 10 ms, 11 ms, 13 ms, 14 ms, 15 ms, 17 ms, 18 ms, or 19 ms, the slave motor PID controller responds to the tension error signal and generates a slave motor control signal, thereby updating the slave motor control signal and updating the output tension of the slave motor.

[0065] When the current moment is 7.6 ms or 18.1 ms, the running times of the main motor PID controller and the slave motor PID controller are 7.6 ms and 18.1 ms.

[0066] The values obtained by dividing the above-mentioned running time by the time intervals of the main motor PID controller are not integers. Therefore, at the moment of 7.6 ms or 18.1 ms, the main motor PID controller does not respond to the tension error signal, does not generate a main motor control signal, keeps the original main motor control signal unchanged, and does not change the output tension of the main motor.

[0067] The values obtained by dividing the above-mentioned running time by the time intervals of the slave motor PID controller are not integers. Therefore, at the moment of 7.6 ms or 18.1 ms, the slave motor PID controller does not respond to the tension error signal, does not generate a slave motor control signal, keeps the original slave motor control signal unchanged, and does not change the output tension of the slave motor.

[0068] Through the specific implementation process of the method involved in this embodiment, in the case where a large tension range needs to be controlled, while achieving fine control of the tension through the main motor and the slave motor, the response speed to the tension error signal is improved by utilizing the fast response speed of the slave motor.

[0069] Embodiment 2 discloses a system related to the present invention, and discloses the specific process of how the system involved in this embodiment runs the method involved in Embodiment 1. Refer to Figures 3 to 4 。

[0070] In the system involved in this embodiment, the modules of the system include: a main control module, the main control module includes: a main motor, a main motor PID controller and a first clock source; a slave control module, the slave control module includes: a slave motor, a slave motor PID controller and a second clock source; a tension acquisition module, the tension acquisition module includes: a sensor reading determiner and two tension sensors; and an error signal acquisition module.

[0071] The main control module generates a main motor control signal in response to the tension error signal at a first time interval through a first clock source, and controls the output tension of the main motor through the main motor control signal.

[0072] The slave control module generates a slave motor control signal in response to the tension error signal at second time intervals via a second clock source, and controls the output tension of the slave motor via the slave motor control signal.

[0073] The first clock source and the second clock source are independent of each other, and the first time interval is greater than the second time interval; the first time interval is an integer multiple of the second time interval; and the first time interval is at least four times the second time interval.

[0074] The first clock source generates a specific signal at every first time interval and transmits it to the clock source control module. The clock source control module sends a specific signal to the main control module. When the main control module receives the specific signal, the main motor PID controller responds to the tension error signal and generates a main motor control signal.

[0075] The second clock source generates a specific signal at every second time interval and transmits it to the clock source control module. The clock source control module sends a specific signal to the slave control module. When the slave control module receives the specific signal, the slave motor PID controller generates a slave motor control signal in response to the tension error signal.

[0076] When the first clock source and the second clock source generate specific signals at the same time, the clock source control module sets the sending task of the specific signal generated by the second clock source to a blocked state until the error signal is updated, at which time the blocking state of the task is released and the second clock source generates a specific signal that is transmitted to the slave control module.

[0077] After the master motor PID controller or slave motor PID controller controls the master motor or slave motor to output tension, the tension acquisition module obtains the system's actual output tension. The specific process is as follows: Two tension sensors in the tension acquisition module read the system's actual output tension. The sensor reading determiner obtains the values of the two tension sensors and determines the absolute difference between the two tension sensors. Based on the relationship between the absolute difference and the difference threshold, the reliability of the tension feedback value is determined.

[0078] If the absolute difference is greater than the difference threshold, the sensor reading judge determines that at least one of the two tension sensors is faulty, and the entire tension control process ends; if the absolute difference is less than the difference threshold, the sensor reading judge takes the average value of the values of the two tension sensors as the tension feedback value, and transmits the tension feedback value to the error signal acquisition module.

[0079] After receiving the tension feedback value, the error signal acquisition module obtains the difference between the desired tension value at that moment and the tension feedback value, generates the tension error signal at that moment based on the difference, and transmits the tension error signal at that moment to the main motor PID controller and the slave motor PID controller. When the main motor PID controller and the slave motor PID controller receive the tension error signal, they store the error signal.

[0080] Furthermore, when the master control module or the slave control module receives the tension error signal and a characteristic signal from the first clock source or the second clock source, the master motor PID controller in the master control module generates a control signal for the master motor based on the tension error signal. Alternatively, the slave motor PID controller in the slave control module generates a control signal for the slave motor based on the tension error signal.

[0081] When performing tension control, at the initial moment, all devices involved in the system, including the main motor PID controller, the slave motor PID controller, the main motor, and the slave motor, are set to the running state. At the same time, the first clock source and the second clock source generate specific signals. The first clock source and the second clock source will generate specific signals and transmit them to the clock source control system. At this time, the clock source control system sets the sending task of the specific signal generated by the second clock source to the blocked state, and transmits the specific signal generated by the first clock source to the main control module. After receiving the signal, the main control module obtains the tension error signal. The main motor PID controller generates a control signal for the main motor based on the obtained tension error signal to control the output tension of the host. After generating the tension error signal, the clock source control system releases the blocked state of the task, obtains the specific signal generated by the second clock source, and transmits the specific signal generated by the second clock source to the slave control module. After receiving the signal, the slave control module obtains the tension error signal. The slave motor PID controller generates a slave motor control signal based on the obtained tension error signal to control the output tension of the slave motor, so that at the initial time, the output tension of the main motor and the slave motor is close to the desired tension at the initial moment.

[0082] At subsequent moments, if during the control process of the tension, the clock source control system only receives the specific signal generated by the second clock source, then the signal is transmitted to the slave control module. After receiving the signal, the slave control module obtains the tension error signal. The slave motor PID controller generates a slave motor control signal according to the obtained tension error signal to control the output tension of the slave motor.

[0083] If during the control process of the tension, the clock source control system receives the specific signals generated by the first clock source and the second clock source, then the transmission task of the specific signal generated by the second clock source is set to the blocked state, and the specific signal generated by the first clock source is transmitted to the main control module. After receiving the signal, the main control module obtains the tension error signal. The main motor PID controller generates a main motor control signal according to the obtained tension error signal to control the output tension of the main motor, and generates a tension error signal. After generating the tension error signal, the clock source control system releases the transmission task of the specific signal generated by the second clock source and transmits the specific signal generated by the second clock source to the slave control module. After receiving the signal, the slave control module obtains the tension error signal. The slave motor PID controller generates a slave motor control signal according to the obtained tension error signal to control the output tension of the slave motor.

[0084] After determining the output tension of the system, the tension acquisition module acquires the actual output tension of the system, and determines whether to end the tension control process of the system according to the magnitude relationship between the tension sensors. If the system does not end the tension control process, the average value of the numerical values of the two tension sensors is taken as the tension feedback value, and the tension feedback value is transmitted to the error signal acquisition module. The error signal acquisition module generates a tension error signal and continues the tension control process until the control time ends.

[0085] To further elaborate on the technical solution involved in this embodiment, the technical solution of this embodiment will be described in detail through an example below.

[0086] In this example, the specific configuration of the tension control system is as follows: the number of main control modules is one, the number of slave control modules is one, the number of tension acquisition modules is one, the number of error signal acquisition modules is one, the number of first clock sources is one, the number of second clock sources is one, the number of clock source control systems is one, and the difference threshold is 10N.

[0087] The expected tension at the initial moment is 500N, the expected tension at the end moment is 11kN, and the expected tension increases linearly with the increase of the moment. The difference between the end moment and the initial moment is 10000ms. The first clock source generates a specific signal every 4ms and transmits it to the clock source control system, and the second clock source generates a specific signal every 1ms and transmits it to the clock source control system.

[0088] Since the control time is relatively long, some moments are taken as examples for illustration.

[0089] If the current moment is 2000 ms and the expected tension at this time is 2600 N, then the first clock source and the second clock source generate specific signals and transmit them to the clock source control system. The clock source control system sets the transmission task of the specific signal generated by the second clock source to the blocked state, and transmits the specific signal generated by the first clock source to the main control module. After receiving the signal, the main control module obtains the tension error signal. The main motor PID controller generates a main motor control signal according to the obtained tension error signal to control the output tension of the main motor, so that the output tension of the main motor approaches 2600 N. After the system outputs the tension of the main motor, the error acquisition module generates a tension error signal. After the tension error signal is generated, the clock source control system releases the blocked state of the transmission task of the specific signal generated by the second clock source, and the clock source control system transmits the specific signal generated by the second clock source to the slave control module. After receiving the signal, the slave control module obtains the tension error signal. The slave motor control module generates a slave motor control signal according to the obtained tension error signal to control the output tension of the slave motor, so that the sum of the output tensions of the slave motor and the main motor approaches 2600 N.

[0090] Taking the above example, if the values of the two tension sensors of the system are 2598 N and 2601 N respectively, the absolute difference between the values of the two tension sensors is 3 N, which is less than the difference threshold of 10 N. After the system outputs the tension, the sensor reading judge takes the average value of 2599.5 N of the values of the two tension sensors as the tension feedback value and transmits it to the error signal acquisition module; if the values of the two tension sensors of the system are 2590 N and 2602.3 N respectively, the absolute difference between the values of the two tension sensors is 12.3 N, which is greater than the difference threshold of 10 N. Then, after the system outputs the tension, the sensor reading judge ends the entire tension control process.

[0091] If the current moment is 2002 ms and the expected tension at this time is 2602.1 N, then the second clock source generates a specific signal and transmits it to the clock source control system. The clock source control system transmits the specific signal generated by the second clock source to the slave control module. After receiving the signal, the slave control module obtains the tension error signal. The slave motor PID controller generates a slave motor control signal according to the obtained tension error signal to control the output tension of the slave motor, so that the sum of the output tensions of the slave motor and the main motor approaches 2602.1 N.

[0092] Taking the above example, after the system outputs the tension, if the values of the two tension sensors are 2602.2 N and 2603.1 N respectively, the absolute difference between the values of the two tension sensors is 0.9 N, which is less than the difference threshold of 10 N. After the system outputs the tension, the sensor reading discriminator takes the average value of 2602.65 N of the values of the two tension sensors as the tension feedback value and transmits it to the error signal acquisition module; if the values of the two tension sensors are 2601.3 N and 2613.5 N respectively, the absolute difference between the values of the two tension sensors is 12.2 N, which is greater than the difference threshold of 10 N. After the system outputs the tension, the sensor reading discriminator ends the tension control process.

[0093] In this way, when there is a disturbance in the tension on the storage cable car rope or the cable speed, and a tension error occurs, the slave motor can respond in real time to the tension error signal generated by the tension error, so as to achieve the purpose of accurately controlling the tension in real time.

[0094] Embodiment 3 discloses a specific implementation process of the method involved in the present invention. Refer to Figure 5 .

[0095] The specific implementation process of the method involved in this embodiment is as follows.

[0096] Obtain the values of several tension sensors to form a data set, and determine subsequent operations through the tension acquisition module. If the standard deviation of the data set is not less than the stability threshold, end the tension control process; if the standard deviation of the data set is less than the stability threshold, take the average value of the data set as the tension feedback value, and generate a tension error signal according to the tension feedback value.

[0097] In this embodiment, there are two types of tension error signals, namely the first tension error signal and the second tension error signal.

[0098] Among them, the first tension error signal is: the difference between the average value of the expected tension and the tension feedback value at the current moment within the time interval when the main motor PID controller responds to the tension error signal.

[0099] The second tension error signal is: the difference between the expected tension at the current moment and the tension feedback value at the current moment.

[0100] The main motor PID controller and the slave motor PID controller respond to the first tension error signal and the second tension error signal respectively through different time intervals to generate control signals for the main motor and the slave motor.

[0101] It should be noted that the main motor PID controller stores the first tension error signal, and the slave motor PID controller stores the second tension error signal.

[0102] The time interval for the main motor PID controller to respond to the first tension error signal is greater than the time interval for the slave motor PID controller to respond to the second tension error signal; the time interval for the main motor PID controller to respond to the first tension error signal is an integer multiple of the time interval for the slave motor PID controller to respond to the second tension error signal; the time interval for the main motor PID controller to respond to the first tension error signal is at least four times the time interval for the slave motor PID controller to respond to the second tension error signal.

[0103] For the main motor PID controller, if the running time of the main motor PID controller divided by the time interval for the main motor PID controller to respond to the first tension error signal is an integer, then the main motor PID controller generates a control signal for the main motor according to the first tension error signal; if the running time of the main motor PID controller divided by the time interval for the main motor PID controller to respond to the first tension error signal is not an integer, then the main motor PID controller does not generate a control signal for the main motor and keeps the original control signal of the main motor unchanged.

[0104] For the slave motor PID controller, if the running time of the slave motor PID controller divided by the time interval for the slave motor PID controller to respond to the second tension error signal is an integer, then the slave motor PID controller generates a control signal for the slave motor according to the second tension error signal; if the running time of the slave motor PID controller divided by the time interval for the slave motor PID controller to respond to the second tension error signal is not an integer, then the slave motor PID controller does not generate a control signal for the slave motor and keeps the original control signal of the slave motor unchanged.

[0105] When the main motor PID controller and the slave motor PID controller respond to the first tension error signal and the second tension error signal simultaneously, the main motor PID controller preferentially generates a control signal for the main motor according to the first tension error signal. After the tension error signal is updated, the slave motor PID controller generates a control signal for the slave motor according to the second tension error signal.

[0106] The main motor PID controller generates a control signal for the main motor in the following manner.

[0107] Denote the moment when the main motor PID controller responds to the first tension error signal as t k ; the time interval for the main motor PID controller to respond to the first tension error signal is T1; at t k moment, the tension output by the tension control system is the expected tension curve is F(t); at t moment, the difference between the average expected tension and the tension feedback value is ΔF'(t); u_1(t) is the torque output by the main motor at t moment; K 1,p 、K 1,i and K1,D is the adjustment coefficient of the main motor PID controller.

[0108] Then at time t k the control signal of the main motor generated by the main motor PID controller is: where Similarly,

[0109] The way the slave motor PID controller generates the control signal of the slave motor is described as follows.

[0110] Let the time when the slave motor PID controller responds to the second tension control signal be t k ; at time t k the tension output by the tension control system is the desired tension curve is F(t); at time t, the difference between the desired tension and the tension feedback value is ΔF(t); u_2(t) is the torque output by the slave motor at time t; K 2,p 、K 2,i and K 2,D are the adjustment coefficients of the slave motor PID controller.

[0111] Then at time t k the control signal of the main motor generated by the main motor PID controller is: where

[0112] In this way, by controlling the output torques of the main motor and the slave motor, the tensions output by the main motor and the slave motor can be controlled.

[0113] The main motor PID controller and the slave motor PID controller control the output tensions of the main motor and the slave motor respectively through the control signal of the main motor and the control signal of the slave motor.

[0114] To further elaborate on the technical solution involved in this embodiment, the technical solution of this embodiment will be described in detail through an example below.

[0115] In this example, the desired tension at the initial moment is 1000N, the desired tension at the end moment is 20kN, the difference between the end moment and the initial moment is 10000ms, and the desired tension increases linearly with the increase of the moment. The time interval for the main motor PID controller to respond to the first tension error signal is 10ms, and the time interval for the slave motor PID controller to respond to the second tension error signal is 2ms.

[0116] Taking the time period from 10 ms to 20 ms as an example, at the 10 ms moment, the main motor PID controller and the slave motor PID controller respond to the first tension error signal and the second tension error signal. If at the 10 ms moment, the tension feedback value of the tension control system is 1015 N, then the first tension error signal is: 1028.5 N - 1019 N = 9.5 N. The main motor PID controller preferentially generates a control signal for the main motor according to the first tension error signal, controls the main motor to output tension, so that the tension output by the system is updated. If at this time, the tension feedback value of the tension control system is 1028 N, then the second tension error signal is: 1019 N - 1028 N = -9 N. The slave motor PID controller generates a control signal for the slave motor according to the second tension error signal, and controls the output tension of the slave motor.

[0117] At the 15 ms moment, the slave motor PID controller responds to the second tension error signal. If at the 15 ms moment, the tension feedback value of the tension control system is 1029 N, then the second tension error signal is: 1028.5 N - 1029 N = -0.5 N. The slave motor PID controller generates a control signal for the slave motor according to the second tension error signal, and controls the output tension of the slave motor.

[0118] Through the specific implementation process of the method involved in this embodiment, the main motor control signal generated by the main motor PID controller in response to the first tension error signal reduces the absolute value of the error between the tension output by the main motor and the desired tension in subsequent time, and further increases the response speed in the tension control process.

[0119] Embodiment 4. This embodiment discloses the system of the present invention and discloses how the system executes the method involved in Embodiment 3. Refer to Figures 6 to 7 。

[0120] The system involved in this embodiment includes: a main control module, a slave control module, a first clock source, a second clock source, a clock source control system, a tension acquisition module, a first error signal acquisition module, and a second error acquisition module.

[0121] Among them, the main control module includes: a main motor PID controller and a main motor. The main motor PID controller responds to the first tension error signal at a first time interval through the first clock source, generates a control signal for the main motor according to the first tension error signal, and controls the output tension of the main motor through the control signal of the main motor.

[0122] The slave control module includes: a slave motor PID controller and a slave motor. The slave motor PID controller responds to the second tension error signal at a second time interval through the second clock source, generates a control signal for the slave motor according to the second tension error signal, and controls the output tension of the slave motor through the control signal of the slave motor.

[0123] The first clock source generates a specific signal at every first time interval and transmits it to the clock source control module. The clock source control module sends a specific signal to the main control module. When the main control module receives the specific signal, the main motor PID controller responds to the first tension error signal and generates a main motor control signal.

[0124] The second clock source generates a specific signal at every second time interval and transmits it to the clock source control module. The clock source control module sends a specific signal to the slave control module. When the slave control module receives the specific signal, the slave motor PID controller generates a slave motor control signal in response to the second tension error signal.

[0125] When the first clock source and the second clock source generate specific signals at the same time, the clock source control module sets the sending task of the specific signal generated by the second clock source to a blocked state until the tension error signal is updated, at which time the blocking state of the task is released, and the second clock source generates a specific signal that is transmitted to the slave control module.

[0126] The tension acquisition module includes: a sensor reading judge and a certain number of tension sensors. In the tension acquisition module, the number of tension sensors is at least three. The sensor reading judge obtains the values of all tension sensors, generates a data set based on these values, and obtains the standard deviation of the data set. If the standard deviation of the data set is greater than the stability threshold, the sensor reading judge ends the system's tension control process; if the standard deviation of the data set is less than the stability threshold, the sensor reading judge takes the average value of the data set as the tension feedback value of the system.

[0127] After obtaining the tension feedback value of the system, the tension obtaining module transmits the tension feedback value to the first error obtaining module and the second error obtaining module.

[0128] After receiving the tension feedback value, the first error acquisition module obtains the difference between the average expected tension in the time period from the current moment to the current moment plus the time interval of the main motor PID controller responding to the first tension error signal and the tension feedback value of the system at the current moment, generates a first tension error signal based on the difference, and transmits the first tension error signal to the main control module.

[0129] After receiving the tension feedback value, the second error acquisition module obtains the difference between the desired tension at the current moment and the tension feedback value of the system at the current moment, generates a second tension error signal based on the difference, and transmits the second tension error signal to the slave control module.

[0130] When the tension control process is in progress, at the initial moment, all devices involved in the system such as the main motor PID controller, the main motor, the slave motor PID controller, and the slave motor are set to the operating state. At this time, when the clock source control system receives the specific signals generated by the first clock source and the second clock source, it sets the transmission task of the specific signal generated by the second clock source to the blocked state, and transmits the specific signal generated by the first clock source to the main control module. After receiving the signal, the main control module obtains the first tension error signal. The main motor PID controller generates a main motor control signal according to the obtained first tension error signal to control the output tension of the main motor and generate a tension error signal. After generating the tension error signal, the clock source control system releases the transmission task of the specific signal generated by the second clock source and transmits the specific signal generated by the second clock source to the slave control module. After receiving the signal, the slave control module obtains the second tension error signal. The slave motor PID controller generates a slave motor control signal according to the obtained second tension error signal to control the output tension of the slave motor.

[0131] If, during the tension control process, the clock source control system receives the specific signals generated by the first clock source and the second clock source, it sets the transmission task of the specific signal generated by the second clock source to the blocked state, and transmits the specific signal generated by the first clock source to the main control module. After receiving the signal, the main control module obtains the first tension error signal. The main motor PID controller generates a main motor control signal according to the obtained first tension error signal to control the output tension of the main motor and generate a second tension error signal. After generating the second tension error signal, the clock source control system releases the transmission task of the specific signal generated by the second clock source and transmits the specific signal generated by the second clock source to the slave control module. After receiving the signal, the slave control module obtains the second tension error signal. The slave motor PID controller generates a slave motor control signal according to the obtained second tension error signal to control the output tension of the slave motor.

[0132] After determining the output tension of the system, the tension acquisition module acquires the actual output tension of the system, and determines whether to end the tension control process of the system according to the magnitude relationship between the standard deviation of the data set of the values between the tension sensors and the stability threshold. If the system does not end the tension control process, it takes the average value of the data set of the values of all tension sensors as the tension feedback value, and transmits the tension feedback value to the first error signal acquisition module and the second error signal acquisition module. The first error signal acquisition module and the second error signal acquisition module respectively generate the first tension error signal and the second tension error signal, and continue the tension control process until the control time ends.

[0133] Embodiment 5. On the basis of Embodiments 1 to 4, this embodiment discloses the application of the method and system of the present invention in multiple motors.

[0134] In this embodiment, the number of slave motors is not less than 1, and priorities can be set for the slave motors. The priorities of the slave motors can also be determined according to the maximum output torque of the slave motors. The determination method is as follows.

[0135] If, between two slave motors, the maximum output tension of one slave motor is greater than the output power of the other slave motor, then the slave motor with the maximum output tension is the parent motor of the slave motor with the minimum output tension.

[0136] Moreover, among the slave motors, the time interval for the parent motor PID controller to respond to the tension error signal is greater than the time interval for the child motor PID controller to respond to the tension error signal; the time interval for the parent motor PID controller to respond to the tension error signal is an integer multiple of the time interval for the child motor PID controller to respond to the tension error signal; the time interval for the parent motor PID controller to respond to the tension error signal is at least twice the time interval for the child motor PID controller to respond to the tension error signal.

[0137] It should be noted that the main motor has the highest priority and the maximum output tension.

[0138] All motors respond to the tension error signal at different time intervals through independent clock sources to generate control signals to control the output tension of the motors.

[0139] Moreover, when several motor PID controllers respond to the tension error signal simultaneously, the control signals of the motors are generated in sequence according to the priorities of the motors.

[0140] For example, if there are motor 1, motor 2, and motor 3, motor 1 has the highest priority, followed by motor 2, and motor 3 has the lowest priority. There are clock sources 1 to 3. The clock source 1 generates a specific signal and transmits it to the PID controller of motor 1 through the clock source control system. The clock source 2 generates a specific signal and transmits it to the PID controller of motor 2 through the clock source control system. The clock source 3 generates a specific signal and transmits it to the PID controller of motor 3 through the clock source control system.

[0141] At a certain moment, clock source 1 to clock source 3 generate specific signals and transmit them to the clock source control system. Since motor 1 has the highest priority, the clock source control system sets the sending task of the specific signal generated by clock source 2 and the sending task of the specific signal generated by clock source 3 to a blocked state, and transmits the specific signal generated by clock source 1 to the control module where motor 1 is located to control the output tension of motor 1 until the tension error signal is updated. The clock control system releases the blocking state of the sending task of the specific signal generated by clock source 2, and transmits the specific signal generated by clock source 2 to the control module where motor 2 is located to control the output tension of motor 2 until the tension error signal is updated. The clock control system releases the blocking state of the sending task of the specific signal generated by clock source 3, and transmits the specific signal generated by clock source 3 to the control module where motor 3 is located to control the output tension of motor 3.

[0142] When the power price 1, power price 2 and motor 3 respond to the tension error signal at the same time, the PID controller of motor 1 generates the control signal of the motor first until the tension error signal is updated. The PID controller of motor 2 generates the control signal of the motor until the tension error signal is updated. The PID controller of motor 3 generates the control signal of the motor.

[0143] Through the technical solution of this embodiment, the method and system involved in the present invention can be applied to multi-motor application scenarios, and the method and system involved in the present invention can be applied to tension control in multi-motor scenarios, with high scalability and wider application scenarios.

[0144] It is necessary to further explain the background of the problems solved by Examples 1 to 5. Figure 8 , Figure 8 This is a schematic diagram of a tension simulation process. In the figure, Y0 represents the moment when the master motor PID controller and the slave motor PID controller respond to the tension error signal; Y1 represents the moment when the slave motor PID controller responds to the tension error signal. During the tension simulation process, for the stored cable rope tension F out During operation, the length of the cable stored on the storage cable car changes, causing the storage cable car's rotational inertia to change. At the same time, since the storage cable car's damping is relatively small, the change in the storage cable car's rotational inertia can easily cause the rope tension F out Fluctuations occur. The damping ratio of the tension reducing device is also small, making F out The fluctuation of the controlled tension F in Therefore, through the technical solutions of Examples 1 to 5, in application scenarios with a large range of tension control, the response speed to tension errors is improved, thereby ensuring the control accuracy of tension.

[0145] The present invention deeply elaborates its purpose, technical solution and beneficial effects through specific embodiments. However, these embodiments are only examples to show the application modes of the invention and do not constitute a limitation on the protection scope of the present invention. We clearly point out that any reasonable modification, equivalent replacement or technical improvement under the guidance of the spirit and principle of the present invention should be included in the protection scope of the present invention. This means that as long as these changes do not deviate from the core idea and basic functions of the invention, they should be protected by the patent right. The protection scope of the present invention should be broad, including all direct and obvious variants as well as non-obvious innovations that can be reasonably deduced by technical experts based on the disclosed content of the present invention. This broad protection aims to promote further research and development based on the present invention and at the same time ensure that its innovation and practicality are comprehensively protected by law.

Claims

1. A tension control method, characterized in that, The method steps include: Read the values of several tension sensors in real time, obtain the tension feedback value, and obtain the tension error signal according to the tension feedback value; The main motor PID controller and the slave motor PID controller respectively respond to the tension error signal at different time intervals, and generate control signals for the main motor and the slave motor according to the tension error signal; The main motor PID controller and the slave motor PID controller control the tension output of the main motor and the slave motor through the control signal.

2. The tension control method according to claim 1, characterized in that The time interval for the main motor PID controller to respond to the tension error signal is greater than the time interval for the slave motor PID controller to respond to the tension error signal.

3. The tension control method according to claim 2, characterized in that, The time interval for the main motor PID controller to respond to the tension error signal is an integer multiple of the time interval for the slave motor PID controller to respond to the tension error signal.

4. A tension control method according to claim 2 or 3, characterized in that, The time interval for the main motor controller to respond to the tension error signal is at least four times the time interval for the slave motor PID controller to respond to the tension control signal.

5. A tension control method according to any one of claims 1 to 3, characterized in that, If the standard deviation of the value set of the tension sensors is not less than the stable threshold, end the process of the method; if the standard deviation of the value set of the tension sensors is less than the stable threshold, take the average value of the values of all the tension sensors as the tension control feedback value.

6. A tension control method according to any one of claims 1 to 3, characterized in that, If the absolute difference between the values of the tension sensors is not less than the difference threshold, end the process of the method; if the absolute difference between the values of the tension sensors is less than the difference threshold, take the average value of the values of all the tension sensors as the tension control feedback value.

7. A tension control system, which executes the method according to any one of claims 1 to 6, characterized in that, The system includes: The main control module, including: the main motor PID controller and the main motor; The main motor PID controller responds to the tension error signal at a first time interval through a first clock source to generate a control signal for the main motor; The slave control module, including: the slave motor PID controller and the slave motor; The slave motor PID controller responds to the tension error signal at a second time interval through a second clock source to generate a control signal for the slave motor.

8. A tension control system according to claim 7, characterized in that, The system includes: The tension acquisition module, the tension acquisition module includes: a sensor reading judge and several tension sensors; The number of the tension sensors is at least two, and the tension sensors acquire the actual output tension of the system and output values; The sensor reading judge acquires the values of several tension sensors, and acquires the tension feedback value of the system according to the values.

9. A tension control system according to claim 8, wherein, The system includes: The error signal acquisition module, the error signal acquisition module acquires the tension feedback value of the sensor reading judge, acquires the difference between the expected tension and the tension feedback value in real time, generates the tension error signal, and transmits the tension error signal to the main motor PID controller or the slave motor PID controller.

10. A tension control system according to any one of claims 7 to 9, characterized in that, The first time interval is greater than the second time interval.

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