Limiting method of variable-frequency speed-regulating electric shovel and variable-frequency speed-regulating electric shovel

Abstract

The invention discloses a limiting method of a variable-frequency speed-regulating electric shovel and the variable-frequency speed-regulating electric shovel. The method comprises the steps that the position zero point of a mechanism, the forward direction and the reverse direction of the relative position zero point, a first limiting point located in the forward direction and a second limiting point located in the reverse direction are preset; responding to the action of the mechanism, acquiring the operation distance and the operation speed of the mechanism in real time, setting the speed of a frequency converter corresponding to the mechanism as zero when the mechanism operates in the forward direction and the forward operation distance of the mechanism relative to the position zero point meets a set condition, and setting the speed of the frequency converter corresponding to the mechanism as zero when the mechanism operates in the reverse direction; and when the reverse running distance of the mechanism relative to the position zero point meets a set condition, setting the given speed of the frequency converter corresponding to the mechanism to be zero. It can be guaranteed that the mechanism accurately stops at a set limiting point, the situation that an electric shovel is damaged due to overrun of the mechanism is avoided, the bucket of the electric shovel can run at a high speed within the maximum range, and the production efficiency of the electric shovel is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric shovel control, and in particular to a limiting method for a variable frequency speed regulating electric shovel and a variable frequency speed regulating electric shovel. Background Art

[0002] An electric shovel (also known as a mining mechanical shovel) is an electrically driven mechanical device, mainly used for ore mining and rock and soil stripping in open-pit mines. Figure 1 , Figure 1 The schematic diagram of the structure of an electric shovel in the prior art mainly includes a slewing mechanism, a pushing mechanism, a lifting mechanism, and a traveling mechanism. When the electric shovel is in operation, the bucket moves under the combined action of the pushing mechanism and the lifting mechanism to complete the material excavation. Among them, in the variable frequency speed regulating electric shovel, the movement of the lifting mechanism is completed by the frequency converter corresponding to the lifting mechanism driving the motor in the lifting mechanism, and the movement of the pushing mechanism is completed by the frequency converter corresponding to the pushing mechanism driving the motor in the pushing mechanism.

[0003] The lifting mechanism and the pushing mechanism work together to complete the material excavation. During operation, if the lifting mechanism continues to move upward, the lifting beam may hit the sheave, which may cause damage to the sheave in serious cases. If the lifting mechanism continues to descend, the bucket will fall to the ground and the lifting wire rope will jump out of the rope groove due to being too loose, thereby damaging the wire rope. Therefore, the lifting mechanism needs to be set with upper and lower limits for protection; because the pushing mechanism adopts a gear rack structure, when the bucket arm runs to the end of the rack (the front and rear baffles of the pushing bucket arm), it will cause an impact on the pushing reducer and damage the pushing large and small gears. Therefore, the pushing mechanism also needs to be set with front and rear limits for protection.

[0004] At present, when performing limit protection for the lifting mechanism and the pushing mechanism, absolute encoders for position detection are respectively installed on the transmission chains of the lifting mechanism and the pushing mechanism. At the same time, for the lifting mechanism, several pre-deceleration points and one limit point are set based on a fixed lifting operation speed. When the lifting mechanism runs to the pre-deceleration point, the speed is reduced as a percentage of the current speed. When the lifting mechanism runs to the limit point, the speed setting is set to zero. For the pushing mechanism, several pre-deceleration points and one limit point are set based on a fixed pushing operation speed. When the pushing mechanism runs to the pre-deceleration point, the speed is reduced as a percentage of the current speed. When the pushing mechanism runs to the limit point, the speed setting is set to zero.

[0005] However, in actual application of the above-mentioned limit protection method, since the pre-deceleration point and the limit point are set according to a fixed operating speed, when the electric shovel runs at a relatively low speed, there will be a low-speed running section after exceeding the pre-deceleration point. Due to the existence of the low-speed running section, the running speed of the electric shovel is reduced, affecting the production efficiency of the electric shovel; more importantly, the speed at which the electric shovel reaches the limit point is different from the pre-set speed, and the final stop position is also different, and the accurate parking of the electric shovel cannot be guaranteed; when the electric shovel runs at a relatively high speed, the speed at which the electric shovel reaches the limit point is too high, resulting in the final stop position exceeding the limit, and the limit protection effect cannot be achieved. Summary of the invention

[0006] In order to solve some or all of the technical problems existing in the above-mentioned prior art, the present invention provides a limiting method for a variable frequency speed regulating electric shovel and a variable frequency speed regulating electric shovel.

[0007] The technical solution of the present invention is as follows:

[0008] In a first aspect, a method for limiting a variable frequency speed regulating electric shovel is provided, the method comprising:

[0009] Presetting the position zero point of the mechanism, the positive and reverse directions relative to the position zero point, and the first limit point located in the positive direction and the second limit point located in the reverse direction;

[0010] In response to the action of the mechanism, the running distance and running speed of the mechanism are obtained in real time. When the mechanism runs forward and the forward running distance of the mechanism relative to its position zero point meets the condition "S 正向 ≥S 第一限位点 -S 机构 ", set the inverter speed setting corresponding to the mechanism to zero. When the mechanism runs in the reverse direction and the reverse running distance of the mechanism relative to its position zero point meets the condition "S 反向 ≤S 第二限位点 +S 机构 ", set the inverter speed setting corresponding to the mechanism to zero;

[0011] Among them, S 正向 Indicates the positive running distance of the mechanism relative to its position zero point, S 第一限位点 Indicates the distance between the first limit point of the mechanism and its position zero point, S 机构 Indicates the distance the mechanism continues to run after the inverter speed setting is set to zero, S 反向 Indicates the reverse running distance of the mechanism relative to its position zero point, S 第二限位点 Indicates the distance between the second limit point of the mechanism and its position zero point, S 正向 , S 第一限位点 and S 机构 Take it as a positive number, S 反向 and S 第二限位点 Take a negative number.

[0012] In some optional embodiments, the mechanism includes: a lifting mechanism and / or a pushing mechanism.

[0013] In some optional embodiments, when the mechanism is a lifting mechanism, the forward running distance S of the mechanism relative to its position zero point is 正向 Calculated using the following formula:

[0014]

[0015] The reverse running distance S of the mechanism relative to its position zero point 反向 Calculated using the following formula:

[0016]

[0017] Among them, n 卷筒 Indicates the lifting drum speed of the lifting mechanism, d 卷筒 It represents the diameter of the lifting drum, N1 represents the number of pulses output by the first absolute encoder for position detection installed on the lifting mechanism with position zero as the reference point, M1 represents the number of pulses per circle of the first absolute encoder, and i1 represents the speed ratio from the first absolute encoder shaft to the lifting drum shaft.

[0018] In some optional embodiments, when the mechanism is a push mechanism, the forward running distance S of the mechanism relative to its position zero point is 正向 Calculated using the following formula:

[0019]

[0020] The reverse running distance S of the mechanism relative to its position zero point 反向 Calculated using the following formula:

[0021]

[0022] Among them, n 齿轮 Indicates the speed of the pushing gear of the pushing mechanism, d 齿轮 represents the diameter of the pushing gear, N2 represents the number of pulses output by the second absolute encoder for position detection installed on the pushing mechanism with the position zero point as the reference point, M2 represents the number of pulses per circle of the second absolute encoder, and i2 represents the speed ratio from the second absolute encoder shaft to the pushing gear shaft.

[0023] In some optional embodiments, the speed setting of the frequency converter is set to zero, and the mechanism continues to run the distance S 机构 Calculated using the following formula:

[0024]

[0025] Among them, k机构 Indicates the proportional coefficient of the inverter corresponding to the predetermined mechanism, ν 机构 Indicates the operating speed of the mechanism.

[0026] In some optional implementations, the proportionality coefficient k of the frequency converter corresponding to the mechanism is 机构 Determined using the following formula:

[0027]

[0028] Among them, t 减速时间 Indicates the set inverter deceleration time, ν 最高运行速度 Indicates the maximum operating speed of the set mechanism.

[0029] In a second aspect, a variable frequency speed regulating electric shovel is also provided, and the variable frequency speed regulating electric shovel uses the above-mentioned limiting method.

[0030] The main advantages of the technical solution of the present invention are as follows:

[0031] The limiting method of the variable frequency speed regulating electric shovel and the variable frequency speed regulating electric shovel of the present invention obtain the running distance and running speed of the mechanism in real time. When the running distance of the mechanism meets the set conditions, the inverter speed setting corresponding to the mechanism is set to zero, which can ensure that the mechanism stops accurately at the set limit point, avoid the damage of the electric shovel caused by the mechanism exceeding the limit, and enable the electric shovel bucket to run at high speed within the maximum range, thereby improving the production efficiency of the electric shovel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part 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 an improper limitation of the present invention.

[0033] In the figure:

[0034] Figure 1 It is a structural schematic diagram of an electric shovel in the prior art;

[0035] Figure 2 The present invention provides a flow chart of a method for limiting a variable frequency speed regulating electric shovel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] The technical solution provided by the embodiments of the present invention is described in detail below with reference to the accompanying drawings.

[0038] refer to Figure 2 In a first aspect, an embodiment of the present invention provides a limiting method for a variable frequency speed regulating electric shovel, the method comprising the following steps:

[0039] Step 1, presetting the position zero point of the mechanism, the positive and reverse directions relative to the position zero point, and the first limit point located in the positive direction and the second limit point located in the reverse direction;

[0040] In an embodiment of the present invention, the position zero point of the mechanism, the forward and reverse directions relative to the position zero point, and the first limit point located in the forward direction and the second limit point located in the reverse direction are specifically set according to actual needs, and the distance between the first limit point located in the forward direction of the mechanism and the position zero point of the mechanism is equal to the set maximum forward running distance of the mechanism relative to its position zero point, and the distance between the second limit point located in the reverse direction of the mechanism and the position zero point of the mechanism is equal to the set maximum reverse movement distance of the mechanism relative to its position zero point.

[0041] Step 2, in response to the action of the mechanism, the running distance and running speed of the mechanism are obtained in real time. When the mechanism is running forward and the forward running distance of the mechanism relative to its position zero point meets the condition "S 正向 ≥S 第一限位点 -S 机构 ", set the inverter speed setting corresponding to the mechanism to zero. When the mechanism runs in the reverse direction and the reverse running distance of the mechanism relative to its position zero point meets the condition "S 反向 ≤S 第二限位点 +S 机构 ", set the inverter speed setting corresponding to the mechanism to zero;

[0042] In the embodiment of the present invention, S 正向 Indicates the positive running distance of the mechanism relative to its position zero point, S 第一限位点 Indicates the distance between the first limit point of the mechanism and its position zero point, S 机构 Indicates the distance the mechanism continues to run after the inverter speed setting is set to zero, S 反向 Indicates the reverse running distance of the mechanism relative to its position zero point, S 第二限位点 Indicates the distance between the second limit point of the mechanism and its position zero point, S 正向 , S 第一限位点 and S 机构 Take it as a positive number, S 反向 and S 第二限位点 Take a negative number.

[0043] The limiting method for a variable frequency speed regulating electric shovel provided in an embodiment of the present invention obtains the running distance and running speed of the mechanism in real time. When the running distance of the mechanism meets the set conditions, the inverter speed setting corresponding to the mechanism is set to zero. This can ensure that the mechanism stops accurately at the set limit point, avoid damage to the electric shovel caused by the mechanism exceeding the limit, and enable the electric shovel bucket to run at high speed within the maximum range, thereby improving the production efficiency of the electric shovel.

[0044] Further, in an embodiment of the present invention, the mechanism includes: a lifting mechanism and / or a pushing mechanism.

[0045] In an embodiment of the present invention, when the mechanism is a lifting mechanism, the position of the lifting mechanism when the boom of the electric shovel is in a horizontal state and the lifting wire rope is in a vertical state can be defined as the position zero point of the lifting mechanism, the relative position zero point is set upward as the positive direction, and the relative position zero point is set downward as the reverse direction, the distance between the first limit point located in the positive direction and the position zero point is equal to the set maximum upward running distance of the lifting mechanism relative to its position zero point, and the distance between the second limit point located in the reverse direction and the position zero point is equal to the set maximum downward running distance of the lifting mechanism relative to its position zero point.

[0046] In an embodiment of the present invention, when the mechanism is a pushing mechanism, the position of the pushing mechanism when the boom of the electric shovel is in a horizontal state and the lifting wire rope is in a vertical state can be defined as the position zero point of the pushing mechanism, the forward direction relative to the position zero point is set as the positive direction, and the backward direction relative to the position zero point is set as the reverse direction, the distance between the first limit point located in the positive direction and the position zero point is equal to the set maximum forward running distance of the pushing mechanism relative to its position zero point, and the distance between the second limit point located in the reverse direction and the position zero point is equal to the set maximum backward running distance of the pushing mechanism relative to its position zero point.

[0047] Further, in the embodiment of the present invention, when the mechanism is a lifting mechanism, according to the structural form of the lifting mechanism of the electric shovel, the forward running distance S of the lifting mechanism relative to its position zero point is 正向 Calculated using the following formula:

[0048]

[0049] The reverse running distance S of the lifting mechanism relative to its position zero 反向 Calculated using the following formula:

[0050]

[0051] Among them, n 卷筒 Indicates the lifting drum speed of the lifting mechanism, d 卷筒It represents the diameter of the lifting drum, N1 represents the number of pulses output by the first absolute encoder for position detection installed on the lifting mechanism with position zero as the reference point, M1 represents the number of pulses per circle of the first absolute encoder, and i1 represents the speed ratio from the first absolute encoder shaft to the lifting drum shaft.

[0052] Further, in the embodiment of the present invention, when the mechanism is a pushing mechanism, according to the structural form of the pushing mechanism of the electric shovel, the forward running distance S of the pushing mechanism relative to its position zero point is 正向 Calculated using the following formula:

[0053]

[0054] The reverse running distance S of the pushing mechanism relative to its position zero 反向 Calculated using the following formula:

[0055]

[0056] Among them, n 齿轮 Indicates the speed of the pushing gear of the pushing mechanism, d 齿轮 represents the diameter of the pushing gear, N2 represents the number of pulses output by the second absolute encoder for position detection installed on the pushing mechanism with the position zero point as the reference point, M2 represents the number of pulses per circle of the second absolute encoder, and i2 represents the speed ratio from the second absolute encoder shaft to the pushing gear shaft.

[0057] Furthermore, since the movement of the lifting mechanism and the pushing mechanism of the variable frequency speed regulation electric shovel is completed by the motor of each mechanism driven by the frequency converter, when the frequency converter speed setting corresponding to the mechanism is set to zero, the mechanism will not stop immediately. The mechanism will decelerate according to the preset deceleration time based on the speed regulation characteristics of the frequency converter. Within the preset frequency converter deceleration time, the mechanism will decelerate from the current running speed to a stationary state. The running distance of the mechanism when it decelerates from the current running speed to a stationary state is the above-mentioned continued running distance of the mechanism after the frequency converter speed setting is set to zero.

[0058] In the embodiment of the present invention, according to the characteristics of the frequency converter provided on the electric shovel, the frequency converter speed setting is set to zero, and the mechanism continues to run the distance S 机构 The running speed of the mechanism when the inverter speed setting is set to zero ν 机构 The following relationship is satisfied:

[0059]

[0060] Among them, S 机构 Indicates the distance the mechanism continues to run after the inverter speed setting is set to zero, ν 机构represents the operating speed of the mechanism when the inverter speed setting is set to zero, t represents the operating time of the mechanism after the inverter speed setting is set to zero, ν 最高运行速度 Indicates the maximum operating speed of the preset mechanism, t 减速时间 Indicates the preset deceleration time of the inverter, k 机构 Indicates the proportional coefficient of the inverter corresponding to the mechanism.

[0061] Based on the above relationship, the proportional coefficient k of the inverter corresponding to the mechanism 机构 It is expressed as:

[0062]

[0063] It can be seen from the above relationship that after the inverter speed setting is set to zero, the continued running distance of the mechanism is proportional to the square of the mechanism's running speed when the inverter speed setting is set to zero, and the continued running distance of the mechanism can be calculated based on the mechanism's running speed. Therefore, by utilizing the above-mentioned limiting method, the mechanism can be accurately parked and the electric shovel bucket can run at high speed within the maximum range.

[0064] Furthermore, in the embodiment of the present invention, since the movement of the lifting mechanism and the pushing mechanism of the variable frequency speed regulating electric shovel is completed by the corresponding frequency converter driving the electric motors of each mechanism, the operating speed of the lifting mechanism and the pushing mechanism can be obtained in real time by using PLC to exchange data with the frequency converter through the field bus.

[0065] In a second aspect, an embodiment of the present invention further provides a variable frequency speed regulating electric shovel, which uses the above-mentioned limiting method to control the mechanism.

[0066] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, "front", "back", "left", "right", "upper" and "lower" in this article are all referenced to the placement state shown in the accompanying drawings.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for limiting the position of a variable frequency speed regulating electric shovel, characterized in that: The method comprises: Presetting the position zero point of the mechanism, the positive and reverse directions relative to the position zero point, and the first limit point located in the positive direction and the second limit point located in the reverse direction; In response to the action of the mechanism, the running distance and running speed of the mechanism are obtained in real time. When the mechanism runs forward and the forward running distance of the mechanism relative to its position zero point meets the condition "S 正向 ≥S 第一限位点 -S 机构 ", set the inverter speed setting corresponding to the mechanism to zero. When the mechanism runs in the reverse direction and the reverse running distance of the mechanism relative to its position zero point meets the condition "S 反向 ≤S 第二限位点 +S 机构 ", set the inverter speed setting corresponding to the mechanism to zero; Among them, S 正向 Indicates the positive running distance of the mechanism relative to its position zero point, S 第一限位点 Indicates the distance between the first limit point of the mechanism and its position zero point, S 机构 Indicates the distance the mechanism continues to run after the inverter speed setting is set to zero, S 反向 Indicates the reverse running distance of the mechanism relative to its position zero point, S 第二限位点 Indicates the distance between the second limit point of the mechanism and its position zero point, S 正向 , S 第一限位点 and S 机构 Take it as a positive number, S 反向 and S 第二限位点 Take a negative number.

2. The limiting method of the variable frequency speed regulating electric shovel according to claim 1 is characterized in that: The mechanism includes: a lifting mechanism and / or a pushing mechanism.

3. The limiting method of the variable frequency speed regulating electric shovel according to claim 2 is characterized in that: When the mechanism is a lifting mechanism, the forward running distance S of the mechanism relative to its position zero point 正向 Calculated using the following formula: The reverse running distance S of the mechanism relative to its position zero point 反向 Calculated using the following formula: Among them, n 卷筒 Indicates the lifting drum speed of the lifting mechanism, d 卷筒 It represents the diameter of the lifting drum, N1 represents the number of pulses output by the first absolute encoder for position detection installed on the lifting mechanism with position zero as the reference point, M1 represents the number of pulses per circle of the first absolute encoder, and i1 represents the speed ratio from the first absolute encoder shaft to the lifting drum shaft.

4. The limiting method of the variable frequency speed regulating electric shovel according to claim 2 is characterized in that: When the mechanism is a push mechanism, the forward running distance S of the mechanism relative to its position zero point 正向 Calculated using the following formula: The reverse running distance S of the mechanism relative to its position zero point 反向 Calculated using the following formula: Among them, n 齿轮 Indicates the speed of the pushing gear of the pushing mechanism, d 齿轮 represents the diameter of the pushing gear, N2 represents the number of pulses output by the second absolute encoder for position detection installed on the pushing mechanism with the position zero point as the reference point, M2 represents the number of pulses per circle of the second absolute encoder, and i2 represents the speed ratio from the second absolute encoder shaft to the pushing gear shaft.

5. The limiting method of a variable frequency speed regulating electric shovel according to any one of claims 1 to 4, characterized in that: After the inverter speed is set to zero, the mechanism continues to run distance S 机构 Calculated using the following formula: Among them, k 机构 Indicates the proportional coefficient of the inverter corresponding to the predetermined mechanism, ν 机构 Indicates the operating speed of the mechanism.

6. The limiting method of the variable frequency speed regulating electric shovel according to claim 5 is characterized in that: The proportional coefficient k of the frequency converter corresponding to the mechanism 机构 Determined using the following formula: Among them, t 减速时间 Indicates the set inverter deceleration time, ν 最高运行速度 Indicates the maximum operating speed of the set mechanism.

7. A variable frequency speed regulating electric shovel, characterized in that: The variable frequency speed regulating electric shovel uses the limiting method as described in any one of claims 1-6.

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