Towed excavator control method and system and towed excavator

Abstract

The invention provides a towed electric excavator control method and system and a towed electric excavator, and relates to the technical field of towed electric excavators. The method comprises the steps that the environment temperature and the cable temperature at a roller of the towed electric excavator are obtained; calculating a deviation temperature according to the environment temperature and the cable temperature; and motor control parameters are obtained based on the deviation temperature and / or the cable temperature, the motor load of the towed excavator is controlled according to the motor control parameters, and the motor load is made to be matched with the cable temperature and the environment temperature. The service life of the cable of the towed excavator can be prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of towed electric excavators, and in particular to a control method and system for towed electric excavators and the towed electric excavator. Background Art

[0002] The current new energy excavators mainly include two power supply methods: battery power supply and tow power supply. Among them, the tow power excavator is powered by cables. Compared with the battery power supply, since the external power supply can provide stable and continuous power, it has the advantages of strong continuous power supply capacity, low weight and stable performance, and is more suitable for long-term continuous operation.

[0003] The body of the towed electric excavator is provided with a drum, on which the cable is wound and connected to an external power source to power the excavator. When the excavator is working, the cable is retracted and released by controlling the drum to ensure stable power supply to the excavator. However, during the long-term continuous operation of the towed electric excavator, the cable will continue to heat up. If the cable is in an overheated state for a long time, it will affect the cable life. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a control method and system for a towed electric excavator and a towed electric excavator, which can monitor the cable temperature of the towed electric excavator to avoid long-term overheating of the cable and improve the cable life.

[0005] In order to achieve the above object, according to some embodiments, a first aspect of the present invention provides a method for controlling a towed electric excavator, comprising:

[0006] Obtain the ambient temperature and the cable temperature at the drum of the electric tug excavator;

[0007] Calculate the deviation temperature based on the ambient temperature and cable temperature;

[0008] The motor control parameters are obtained based on the deviation temperature and / or the cable temperature, and the motor load of the electric tow excavator is controlled according to the motor control parameters so that the motor load matches the cable temperature and the ambient temperature.

[0009] A second aspect of the present invention provides a control system for a towed electric excavator, comprising:

[0010] A temperature acquisition module is configured to acquire an ambient temperature and a cable temperature at a drum of the electric towed excavator;

[0011] A calculation module is configured to calculate a deviation temperature according to an ambient temperature and a cable temperature;

[0012] The control module is configured to obtain motor control parameters based on the deviation temperature and / or the cable temperature, and control the motor load of the electric tow excavator according to the motor control parameters to match the motor load with the cable temperature and the ambient temperature.

[0013] According to a third aspect of the present invention, there is provided an electric towed excavator, the electric towed excavator having a drum for winding a cable, a plurality of infrared temperature sensors facing the drum being arranged on the outside of the drum for collecting the cable temperature; an ambient temperature sensor is arranged on the body of the electric towed excavator for collecting the ambient temperature; the electric towed excavator also includes a controller, the controller is connected to the infrared temperature sensor and the ambient temperature sensor, and is used to calculate a deviation temperature according to the cable temperature and the ambient temperature, and control the motor load of the electric towed excavator according to the deviation temperature and / or the cable temperature, so that the motor load matches the cable temperature and the ambient temperature.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention provides a control method, system and towed electric excavator. The cable temperature at the drum of the towed electric excavator is monitored and compared with the ambient temperature to evaluate whether the temperature is within a reasonable range, and the motor control parameters are obtained according to the temperature to adjust the motor load. When the cable is detected to be overheated, the motor load is appropriately reduced, thereby avoiding the cable from being in an overheated state for a long time and improving the cable life. In addition, it is also possible to judge whether the towed electric excavator is in an unstarted or just started state according to the cable temperature and the ambient temperature, and perform a reminder or deceleration action accordingly to avoid damage to the towed electric excavator by performing a heavy load operation without residual heat.

[0016] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] Figure 1 This is a flow chart of the method in Embodiment 1 of the present invention;

[0019] Figure 2 Schematic diagram of the location of the infrared temperature sensor;

[0020] Among them, 1. roller; 2. infrared temperature sensor. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] like Figure 1 As shown, some embodiments first provide a method for controlling a towed electric excavator, including:

[0023] Obtain the ambient temperature and the cable temperature at the drum of the electric tug excavator;

[0024] Calculate the deviation temperature based on the ambient temperature and cable temperature;

[0025] The motor control parameters are obtained based on the deviation temperature and / or the cable temperature, and the motor load of the electric tow excavator is controlled according to the motor control parameters so that the motor load matches the cable temperature and the ambient temperature.

[0026] Due to the limitation of the power supply principle, towed electric excavators need to be equipped with a drum for winding cables on the fuselage to meet the power supply needs in different working environments and locations. Compared with traditional excavators powered by diesel engines, the cable life of towed electric excavators is an important factor affecting the reliability of the entire machine. Based on this, it is necessary to analyze the factors affecting the cable life and take effective measures to improve the cable life.

[0027] The main factors affecting the life of the cable are: first, the mismatch between the cable retraction and release speed and the operating speed of the towed electric excavator during operation. Taking the release of the cable of the towed electric excavator as an example, if the rotation speed of the drum is too low, the cable will be subjected to excessive tension. If the rotation speed of the drum is too high, the cable will be released too much, and the excess cable will accumulate on the ground and wear out, thereby reducing the life of the cable. Second, during the long-term continuous operation of the towed electric excavator, the cable will continue to heat up. If the excavator is continuously in a high-load state, the cable will continue to rise in temperature due to the large current. Excessive temperature will accelerate the aging of the cable.

[0028] To address the problem of mismatch between the cable retraction and extension speed and the operating speed of the towed electric excavator, an additional inertial sensor IMU can be added to the body of the towed electric excavator. The IMU can collect the entire machine operating speed of the excavator in real time and send the speed to the excavator controller. The controller adjusts the retraction and extension speed of the drum according to the entire machine operating speed to achieve a match between the retraction and extension speed of the drum and the entire machine operating speed, thereby avoiding speed mismatch affecting the cable life.

[0029] In view of the influence of cable heating on the life of the cable, this embodiment proposes to set an infrared temperature sensor on the outside of the drum of the towed electric excavator. The infrared temperature sensor will collect infrared radiation energy and convert it into a temperature value. In the process of the drum retracting and releasing the cable, the temperature of multiple points of the cable can be detected in real time. In addition, considering that the external ambient temperature will also affect the measurement results, this embodiment also sets an ambient temperature sensor on the fuselage of the towed electric excavator. The ambient temperature sensor can be a thermocouple or a thermistor sensor. By comparing the ambient temperature measured by the ambient temperature sensor and the temperature at the cable measured by the infrared temperature sensor, the difference between the ambient temperature and the cable temperature (i.e., the deviation temperature) can be obtained. The difference reflects the temperature rise of the cable caused by the load, and then it is judged whether the current load will affect the life of the cable.

[0030] The number of infrared temperature sensors can be one or more. In the present embodiment, there are two infrared temperature sensors, which are respectively arranged on both sides of the drum to detect the cable temperature from two directions. For example, a sensor can be arranged on each side of the front and rear of the drum, the front sensor is installed below the support drum platform, and the rear sensor is installed above the support drum platform. A protective cover with good ventilation and heat dissipation is arranged on the outside of each sensor. Multiple temperature measuring points can be set for each sensor, and the measuring point positions are evenly distributed along the circumferential surface of the drum, and the measuring points corresponding to the two sensors are not repeated. The temperatures collected at multiple measuring points are comprehensively judged, and the temperature abnormality is judged when the temperature at the measuring point that exceeds the set proportion is abnormal.

[0031] The infrared temperature sensor is connected to the controller of the towed electric excavator and sends the collected temperature signal to the controller. For the temperature signal collected by the infrared temperature sensor, the controller performs data type conversion, amplification, and filtering in sequence to obtain the corresponding voltage value, and then performs a table lookup operation to convert the temperature signal into the corresponding temperature value. The port is then checked for faults to avoid data abnormalities caused by port abnormalities, and it is determined whether the obtained temperature value is within the valid range. If not, a default temperature value is assigned. If so, the temperature value is processed and output. The ambient temperature sensor is also connected to the controller of the towed electric excavator. The controller performs a table lookup on the collected signal to obtain the corresponding temperature value, and at the same time performs fault detection on the port.

[0032] For the obtained cable temperature (obtained by taking the average value of the temperatures collected at multiple temperature measuring points) and the ambient temperature, on the one hand, the controller sends them to the human-machine interface HMI of the towed electric excavator for display, so that the driver can observe the temperature information in real time. On the other hand, calculation operations are performed on the cable temperature and the ambient temperature, and the cable temperature and the deviation temperature are combined to determine whether there is an abnormality. If there is a temperature abnormality, the corresponding motor control parameters are generated, and the motor of the towed electric excavator is controlled to reduce the load, thereby reducing the heating of the cable.

[0033] The cable temperature and the ambient temperature are subtracted to obtain the deviation temperature. It is determined whether the deviation temperature is greater than a set temperature threshold. In this embodiment, the temperature threshold includes a first temperature threshold T1 and a second temperature threshold T2, T1>T2, wherein T1 is used to determine whether the deviation temperature exceeds an upper limit, and T2 is used to determine whether the deviation temperature is lower than a lower limit.

[0034] If the deviation temperature is greater than the first temperature threshold T1, it indicates that the cable is at risk of overheating. At this time, the first temperature alarm signal is sent to the driver through the HMI to prompt the driver to avoid cable overheating by suspending the operation or reducing the operating load. If the deviation temperature is still greater than the first temperature threshold after the set delay time, a motor control parameter for reducing the load of the electric excavator motor is generated. The controller generates a corresponding speed reduction signal according to the motor control parameter to control the motor to force the speed reduction, thereby reducing the motor load and reducing the cable temperature rise. The speed reduction state is synchronously displayed through the HMI to prompt the driver that the forced torque limit / speed reduction has been triggered due to the excessive cable temperature.

[0035] If the deviation temperature is lower than the second temperature threshold T2, it indicates that the towed electric excavator may be in a state of not working or just starting to work. At this time, the towed electric excavator should be preheated before heavy load operation, and a temperature prompt signal is sent to the driver through HMI to prompt the driver to preheat and determine whether the speed reduction process is required. If the deviation temperature is still lower than the second temperature threshold after the set delay time, a motor control parameter for reducing the load of the towed electric excavator motor is generated. The specific implementation process is the same as when the deviation temperature is greater than the first temperature threshold T1.

[0036] In order to reduce the impact on normal operations, this embodiment also proposes a control method for intermittent load reduction. By setting the intermittent load reduction time, the electric towed excavator is controlled to perform intermittent load reduction. That is, after the first set time of load reduction has passed, the load restriction is released, and after the second set time has passed, it is judged again. If the deviation temperature still exceeds the set temperature threshold, the load reduction for the first set time is executed again, and the cycle is repeated.

[0037] The method for controlling the forced deceleration of the motor by means of the motor control parameters includes: judging whether the deviation temperature is greater than the first temperature threshold value T1 or lower than the second temperature threshold value T2, if not, no additional action is performed; if yes, further judging whether the current motor is already in a deceleration state. If the current motor is already in a deceleration state, no additional action is performed. If the current motor is not in a deceleration state, the motor control parameters are generated to control the motor to force deceleration. The deceleration amplitude is pre-calibrated, for example, the speed can be reduced by a set ratio or a set size, or reduced to a set size. After the first set time time1 (for example, 12 seconds) of forced deceleration is reached, the restriction is lifted and the second set time time2 (for example, 15 seconds) is maintained, and then the deviation temperature is judged again whether it is greater than the first temperature threshold value T1 or lower than the second temperature threshold value T2. If so, the first set time is forced to be decelerated again. The judgment is repeated many times in this way, and the number of continuous forced speed reductions is recorded. If the number of continuous forced speed reductions exceeds the set number N (for example, 10 times), and the deviation temperature is still outside the first temperature threshold T1 or the second temperature threshold T2, continuous forced load reduction is executed, and forced speed reduction is performed until the deviation temperature returns to a reasonable range.

[0038] In addition, when the ambient temperature is in an extreme state, for example, the ambient temperature is high, the cable itself will be in a high temperature environment, and there may be a problem of overheating even though the deviation temperature meets the range set by the first temperature threshold T1 and the second temperature threshold T2. Therefore, this embodiment also judges the cable temperature separately. It is judged whether the cable temperature exceeds the set cable temperature threshold. If the cable temperature is greater than the cable temperature threshold, it indicates that the cable itself is at risk of overheating, and the aforementioned forced speed reduction method is also performed until the cable temperature is lower than the cable temperature threshold. That is, if the cable temperature is greater than the cable temperature threshold, a second temperature alarm signal is sent to the driver through the HMI to prompt the driver to avoid cable overheating by suspending the operation or reducing the operating load; if the cable temperature is still greater than the cable temperature threshold after the set delay time, a motor control parameter for reducing the load of the electric excavator motor is generated, and the controller generates a corresponding deceleration signal according to the motor control parameter to control the motor to force deceleration, thereby reducing the motor load and reducing the cable temperature rise. The deceleration state is synchronously displayed through the HMI to prompt the driver that the forced torque limit / deceleration has been triggered due to the high cable temperature; after the forced deceleration for the first set time time1 (for example, 12 seconds), the restriction is lifted and the second set time time2 (for example, 15 seconds) is maintained, and then it is judged again whether the cable temperature is greater than the cable temperature threshold. If so, the first set time is forced to be decelerated again. This is repeated for many times, and the number of continuous forced decelerations is recorded. If the number of continuous forced decelerations exceeds the set number N (for example, 10 times), and the cable temperature is still greater than the cable temperature threshold, continuous forced load reduction is executed, and forced deceleration is performed until the cable temperature returns to a reasonable range.

[0039] In order to avoid false alarms from the sensor and to prevent the safety of the operation from being affected by speed reduction in emergency situations, it is preferably designed that the forced speed reduction can be manually canceled by the driver through the HMI.

[0040] The embodiment of the present invention further provides a control system for a towed electric excavator, comprising:

[0041] A temperature acquisition module is configured to acquire an ambient temperature and a cable temperature at a drum of the electric towed excavator;

[0042] A calculation module is configured to calculate a deviation temperature according to an ambient temperature and a cable temperature;

[0043] The control module is configured to obtain motor control parameters based on the deviation temperature and / or the cable temperature, and control the motor load of the electric tow excavator according to the motor control parameters to match the motor load with the cable temperature and the ambient temperature.

[0044] It should be noted here that each module in the above system corresponds one by one to the steps of the above method, and the specific implementation process is the same, which will not be repeated here.

[0045] Some embodiments further provide a towed electric excavator, such as Figure 2 As shown, the towed electric excavator has a drum 1 for winding the cable, and a plurality of infrared temperature sensors 2 facing the drum are arranged on the outside of the drum 1 for collecting the cable temperature; an ambient temperature sensor is arranged on the body of the towed electric excavator for collecting the ambient temperature; the towed electric excavator also includes a controller, which is connected to the infrared temperature sensor and the ambient temperature sensor, and is used to calculate the deviation temperature according to the cable temperature and the ambient temperature, and control the motor load of the towed electric excavator according to the deviation temperature and / or the cable temperature, so that the motor load matches the cable temperature and the ambient temperature. The specific implementation process in this embodiment is the same as the above method and will not be repeated.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for a towed electric excavator, characterized in that: include: Obtain the ambient temperature and the cable temperature at the drum of the electric tug excavator; Calculate the deviation temperature based on the ambient temperature and cable temperature; The motor control parameters are obtained based on the deviation temperature and / or the cable temperature, and the motor load of the electric tow excavator is controlled according to the motor control parameters so that the motor load matches the cable temperature and the ambient temperature.

2. A method for controlling a towed electric excavator according to claim 1, characterized in that: The cable temperature at the drum of the electric towed excavator is obtained by calculating the average value based on the temperatures measured at multiple measuring points on the drum.

3. A method for controlling a towed electric excavator according to claim 1, characterized in that: The method of obtaining a motor control parameter based on the deviation temperature and / or the cable temperature, and controlling the motor load of the electric towed excavator according to the motor control parameter so that the motor load matches the cable temperature and the ambient temperature, includes: If the deviation temperature is greater than a first temperature threshold, a first temperature alarm signal is sent; If the deviation temperature is still greater than the first temperature threshold after the set delay time, a motor control parameter for reducing the load of the motor of the electric tow excavator is generated to control the motor to reduce speed; After the motor speed is reduced for a first set time, the restriction is released and maintained for a second set time, and then it is determined again whether the deviation temperature is greater than the first temperature threshold. If the deviation temperature is still greater than the first temperature threshold, the motor speed is controlled to be reduced again.

4. A method for controlling a towed electric excavator as claimed in claim 3, characterized in that: If the number of consecutive speed reductions exceeds the set number, the speed is forced to reduce until the deviation temperature is lower than the first temperature threshold.

5. A method for controlling a towed electric excavator as claimed in claim 3, characterized in that: Also included is sending a temperature prompt signal if the deviation temperature is lower than a second temperature threshold; If the deviation temperature is still lower than the second temperature threshold after the set delay time, a motor control parameter for reducing the load of the motor of the electric tow excavator is generated to control the motor to reduce speed; After the motor speed is reduced for the first set time, the restriction is released and maintained for the second set time, and then it is determined again whether the deviation temperature is lower than the second temperature threshold. If the deviation temperature is still lower than the second temperature threshold, the motor speed is controlled to be reduced again.

6. A method for controlling a towed electric excavator as claimed in claim 3 or 5, characterized in that: If the number of times the motor speed is continuously controlled to decrease exceeds the set number, the speed is forced to decrease until the deviation temperature is lower than the first temperature threshold or higher than the second temperature threshold.

7. A method for controlling a towed electric excavator as claimed in claim 3, characterized in that: Also included is sending a second temperature alarm signal if the cable temperature is greater than a cable temperature threshold; If the cable temperature is still greater than the cable temperature threshold after the set delay time, a motor control parameter for reducing the load on the motor of the electric towed excavator is generated to control the motor to reduce speed; After the motor speed is reduced for the first set time, the restriction is released and maintained for the second set time, and then it is determined again whether the cable temperature is greater than the cable temperature threshold. If the cable temperature is still greater than the cable temperature threshold, the motor speed is controlled to be reduced again.

8. A method for controlling a towed electric excavator as claimed in claim 7, characterized in that: If the number of times the motor speed is continuously reduced exceeds the set number, the speed is forced to be reduced until the cable temperature is lower than the cable temperature threshold.

9. A control system for a towed electric excavator, characterized in that: include: A temperature acquisition module is configured to acquire an ambient temperature and a cable temperature at a drum of the electric towed excavator; A calculation module is configured to calculate a deviation temperature according to an ambient temperature and a cable temperature; The control module is configured to obtain motor control parameters based on the deviation temperature and / or the cable temperature, and control the motor load of the electric tow excavator according to the motor control parameters to match the motor load with the cable temperature and the ambient temperature.

10. A towed electric excavator, characterized in that: The towed electric excavator has a drum for winding the cable, and a plurality of infrared temperature sensors facing the drum are arranged on the outside of the drum for collecting the cable temperature; an ambient temperature sensor is arranged on the body of the towed electric excavator for collecting the ambient temperature; the towed electric excavator also includes a controller, which is connected to the infrared temperature sensor and the ambient temperature sensor, and is used to calculate the deviation temperature according to the cable temperature and the ambient temperature, and control the motor load of the towed electric excavator according to the deviation temperature and / or the cable temperature, so that the motor load matches the cable temperature and the ambient temperature.

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