Automatic mining method and system based on locked-rotor state recognition

Abstract

The invention discloses an automatic excavation method and system based on locked-rotor state recognition. The automatic excavation method comprises the steps that motion parameters of a bucket are obtained in real time; judging whether the torque / current of the lifting motor approaches a preset torque amplitude limit / current amplitude limit or not; based on the lifting speed of the bucket and the pushing speed of the bucket, the bucket speed is calculated in real time, and whether the calculated bucket speed exceeds a preset bucket speed critical value or not is judged; whether the cut-in angle theta of the bucket at the current position is within the range of the preset optimal cut-in angle theta0 or not is judged; and the judgment results of the three conditions are considered cooperatively to determine whether the operation state of the bucket is in the locked-rotor state or not, and then the specific working conditions of the lifting and pushing mechanism are controlled. Therefore, real and effective pre-judgment and recognition of locked-rotor can be achieved, the problem that the excavation action cannot be completely executed due to inaccurate prediction in the past is solved, and closed-loop execution of automatic excavation is achieved.

Description

Technical Field

[0001] The invention relates to an automatic excavation method and system based on stall state recognition, which are applied to a large-scale mining mechanical front shovel excavator. Background Art

[0002] During the normal excavation process of the excavator, as the depth of the bucket's penetration into the material increases and the amount of material accumulated in the bucket increases, its front-end working mechanism must bear the load changes caused by the changes in the relative position and speed between the bucket and the material. In addition, due to the randomness of the material distribution, the change in the bucket load is random, and it is difficult to grasp a definite rule. In actual work, the equipment needs to maintain a dynamic balance between full load rate and avoiding frequent stalls at all times, and achieve the optimal solution of high full bucket rate and short excavation time in a single excavation process, so as to exert its maximum working capacity without damaging the equipment.

[0003] Current methods for automatic excavation treat materials as ideal loose materials, and do not determine whether they are regular loads or possible stalls during the actual excavation process. This results in a low bucket fill rate or a pause in the excavation process due to inaccurate and untimely judgment, making it impossible to complete efficient and continuous excavation actions. Summary of the invention

[0004] The purpose of the present invention is to provide an automatic excavation method and system based on stall status recognition, which identifies the current working state of the bucket through a combination of motion characteristics presented during the movement of the bucket, thereby formulating targeted stall identification strategies according to different working states, so as to achieve truly effective prediction and identification of stalls, so as to dynamically judge and provide real-time feedback on the entire state of the excavation process, thereby solving the problem that the excavation action cannot be fully executed due to inaccurate predictions in the past, and realizing closed-loop execution of automatic excavation.

[0005] In order to achieve the above technical objectives, the present invention will adopt the following technical solutions:

[0006] An automatic mining method based on stall state recognition, comprising:

[0007] Obtain the motion parameters of the bucket in real time, including the bucket lifting speed, bucket pushing speed, bucket cutting angle θ at the current position, and the torque and current of the lifting motor;

[0008] Determine whether the torque / current of the lifting motor is close to the preset torque limit / current limit, and record it as the first determination result;

[0009] Based on the lifting speed of the bucket and the pushing speed of the bucket, the bucket speed is calculated in real time, and it is determined whether the calculated bucket speed exceeds a preset bucket speed critical value, and recorded as a second determination result;

[0010] Determine whether the cutting angle θ of the bucket at the current position is within the range of the preset optimal cutting angle θ0, and record it as the third determination result;

[0011] The first to third judgment results are considered in coordination to determine whether the operating state of the bucket is in a stalled state, thereby controlling the specific working conditions of the lifting and pushing mechanisms.

[0012] Preferably, when the first to third judgment results indicate that the torque / current of the lifting motor approaches the preset torque limit / current limit, and the calculated bucket speed is within the preset bucket speed critical value, and the cutting angle θ of the bucket at the current position exceeds the range of the preset optimal cutting angle θ0, it indicates that the running state of the bucket is in the stalled rotor A state, and the first execution instruction is output to the lifting and pushing mechanisms respectively;

[0013] When the first to third judgment results indicate that the torque / current of the lifting motor approaches the preset torque limit / current limit, and the calculated bucket speed is within the preset bucket speed critical value, and the cutting angle θ of the bucket at the current position is within the preset optimal cutting angle θ0 range, it indicates that the running state of the bucket is in the stalled B state, and the second execution instruction is output to the lifting and pushing mechanisms respectively;

[0014] On the contrary, it indicates that the bucket is in a non-blocked state, and a third execution instruction is output to the lifting and pushing mechanisms respectively;

[0015] Under the control of the first execution command, the lifting and pushing mechanism stops lifting and appropriately retracts pushing to avoid large rocks on the excavation path or reduce excessive load caused by the bucket cutting too deep;

[0016] The lifting and pushing mechanisms, under the control of the second execution instruction, coordinately adjust the cutting angle of the bucket until the cutting angle θ of the bucket at the current position exceeds the range of the preset optimal cutting angle θ0, respectively judging whether the torque / current of the lifting motor of the bucket at the current position is close to the preset torque limit / current limit, and whether the bucket speed exceeds the preset bucket speed critical value; when the judgment result shows that the torque / current of the lifting motor is close to the preset torque limit / current limit, and the bucket speed is at the preset bucket speed critical value, respectively output the first execution instruction to the lifting and pushing mechanisms; when the judgment result shows that the torque / current of the lifting motor is close to the preset torque limit / current limit, and the bucket speed exceeds the preset bucket speed critical value, respectively output the third execution instruction to the lifting and pushing mechanisms;

[0017] The lifting and pushing mechanism maintains the current operating state of the bucket under the control of the third execution instruction.

[0018] Preferably, the optimal cutting angle θ0 of the current position of the bucket is obtained by:

[0019] Under the same material surface working conditions, the PLC controller records the saddle inclination angle θ of several groups of single excavation executions in the manual excavation mode. i and push encoder value N i , denoted as (θ i ,N i );

[0020] The push encoder value is converted into the dipper arm extension through the structural parameters of the push mechanism itself. Without considering the bucket rotation, the bucket moves in a 2D plane. Therefore, each set of saddle inclination angle θ i and push encoder value N i The composition (θ i ,N i ) coordinates correspond to the fixed bucket tooth tip position (x, y);

[0021] The obtained bucket tooth tip position (x, y) is fitted using a 6th-order polynomial to obtain the fitting curve equation of the excavation trajectory as follows:

[0022] y=C6*x 6 +C5*x 5 +C4*x 4 +C3*x 3 +C2*x 2 +C1*x+C0;

[0023] Where: C1-C6 are the coefficients of polynomials of different orders; C0 is a constant;

[0024] The fitting curve equation of the above excavation trajectory is the optimal excavation trajectory equation of the bucket;

[0025] The optimal cut-in angle θ0 at any point A is obtained on the optimal excavation trajectory. The optimal cut-in angle θ0 is the angle between the tangent line at the point A and the x-axis, which is calculated by the following formula:

[0026] θ0=tan -1 (dy / dx)|x=X0;

[0027] Wherein: X0 represents the horizontal coordinate of site A.

[0028] Another technical object of the present invention is to provide an automatic excavation method based on stall state recognition, comprising the following steps:

[0029] The physical characteristics of the current working state of the bucket are calculated by the front-end calculation module and transmitted to the stall state identification execution module;

[0030] The stall state recognition execution module recognizes whether there is a stall state in the current working state of the bucket through the received physical features, and then plans the corresponding control strategy to control the working conditions of the lifting and pushing mechanisms;

[0031] The stall state recognition execution module is constructed through the following steps:

[0032] Step 1: Construct the physical feature set of the bucket:

[0033] After the physical characteristics of the bucket's operating state are decomposed, each physical characteristic is extracted to complete the establishment of the bucket's physical characteristic set;

[0034] Step 2: Establishment of motion feature set:

[0035] The physical features included in the physical feature set constructed in step 1 are freely combined to form several feature elements m i , which can form the bucket motion feature set M = {m1,m2,……,m i ,……m j}, j represents the total number of characteristic elements;

[0036] Step 3: Build the bucket state set:

[0037] The feature elements m included in the motion feature set constructed in step 2 i , reverse analysis of bucket states is performed one by one to realize bucket state recognition, and then bucket state set S = {s1, s2, ..., s i ,……s j}, in the bucket state set, the operation state s of each bucket i and each characteristic element m established in step 1 i One to one correspondence;

[0038] Step 4: Build a policy set:

[0039] For each bucket operation state s in the bucket state set S i , plan the corresponding control strategy p k , to form a strategy set P = {p1, p2, ..., p k ,……p m}, m represents the total number of control strategies in the strategy set.

[0040] Preferably, the front-end calculation module calculates the physical characteristics of the bucket's current working state through the motion parameters of the bucket acquired in real time; the physical characteristics of the bucket's current working state include at least one physical feature in the physical feature set.

[0041] Preferably, the motion parameters of the bucket include the lifting speed of the bucket, the pushing speed of the bucket, the cutting angle θ of the bucket at the current position, and the torque and current of the lifting motor;

[0042] In step 1, the physical feature set includes 3 physical features, corresponding to the first to third physical features, where:

[0043] First physical characteristic: the current / torque approaches the preset current / torque limit;

[0044] Second physical feature: the bucket speed is within a preset bucket speed critical value range;

[0045] The third physical feature: the angle θ between the bucket and the horizontal direction is less than the optimal cutting angle θ0 of the bucket's current position.

[0046] Preferably, the optimal cutting angle θ0 of the current position of the bucket is obtained by:

[0047] Step 1.1: Construct the optimal excavation trajectory equation of the bucket:

[0048] Step 1.1.1, under the same material surface working condition, record the saddle inclination angle θ of several groups of single excavation executions in the manual excavation mode through the PLC controller i and push encoder value N i , denoted as (θ i ,N i );

[0049] Step 1.1.2: The push encoder value is converted into the dipper arm extension through the structural parameters of the push mechanism itself. Without considering the bucket rotation, the bucket moves in a 2D plane. Therefore, each set of saddle inclination angle θ i and push encoder value N i The composition (θ i ,N i ) coordinates correspond to the fixed bucket tooth tip position (x, y);

[0050] Step 1.1.3: Use a sixth-order polynomial to fit the obtained bucket tooth tip position (x, y) to obtain the fitting curve equation of the excavation trajectory as follows:

[0051] y=C6*x 6 +C5*x 5 +C4*x 4 +C3*x 3 +C2*x 2 +C1*x+C0;

[0052] Where: C1-C6 are the coefficients of polynomials of different orders; C0 is a constant;

[0053] The fitting curve equation of the excavation trajectory is the optimal excavation trajectory equation of the bucket;

[0054] Step 1.2, obtain the optimal cut-in angle θ0 at any point A on the optimal excavation trajectory. The optimal cut-in angle θ0 is the angle between the tangent line at the point A and the x-axis, which is calculated by the following formula:

[0055] θ0=tan -1 (dy / dx)|x=X0;

[0056] Wherein: X0 represents the horizontal coordinate of site A.

[0057] Preferably, the motion feature set constructed in step 2 includes each feature element m i , as follows:

[0058] Feature element m1: only includes the first physical feature;

[0059] Feature element m2: only includes the second physical feature;

[0060] Characteristic element m3: only includes the third physical characteristic;

[0061] Characteristic element m4: a combined characteristic consisting of the first physical characteristic and the second physical characteristic;

[0062] Characteristic element m5: a combined characteristic consisting of the first physical characteristic and the third physical characteristic;

[0063] Characteristic element m6: a combined characteristic consisting of the second physical characteristic and the third physical characteristic;

[0064] Feature element m7: a combined feature consisting of the first physical feature, the second physical feature and the third physical feature.

[0065] Preferably, in step 3, each bucket operation state s in the bucket state set S i The details are as follows:

[0066] Bucket operation state s1, corresponding to characteristic element m1;

[0067] Bucket operation state s2, corresponding to characteristic element m2;

[0068] Bucket operation state s3, corresponding to characteristic element m3;

[0069] Bucket operation state S4, corresponding to characteristic element m4;

[0070] Bucket operation state s5, corresponding to characteristic element m5;

[0071] Bucket operation state s6, corresponding to characteristic element m6;

[0072] Bucket operating state s7 corresponds to characteristic element m7.

[0073] Preferably, each control strategy p in the strategy set P k , specifically:

[0074] The control strategy p1 is constructed for bucket operation states s1, s2, s3, and s6; the lifting and pushing mechanism maintains the existing operation state of the bucket unchanged under the control of the control strategy p1;

[0075] Control strategy p2 is constructed for bucket operation state s4; under the control of control strategy p2, the lifting and pushing mechanism stops lifting and appropriately retracts pushing to avoid large rocks on the excavation path or reduce excessive load caused by the bucket cutting too deep;

[0076] Control strategy p3 is constructed for bucket operation state s5; under the control of control strategy p3, the lifting and pushing mechanism maintains the existing operation state of the bucket unchanged;

[0077] Control strategy p4 is constructed for the bucket operating state s7; under the control of control strategy p4, the lifting and pushing mechanisms coordinately adjust the cutting-in angle of the bucket, and trigger the front-end computing module to calculate the first to third physical characteristics in real time; after adjusting the cutting-in angle of the bucket, if the front-end computing module only outputs the first physical characteristic and the second physical characteristic to the stall state identification execution module, the control strategy p2 is triggered; if the front-end computing module only outputs the first physical characteristic to the stall state identification execution module, the control strategy p1 is triggered.

[0078] Another technical objective of the present invention is to provide an automatic excavation system based on stall state recognition, including a system programmed to execute the above-mentioned automatic excavation method based on stall state recognition.

[0079] Based on the above technical objectives, the present invention has the following advantages over the prior art:

[0080] 1. The present invention fully considers the load characteristics of the electric shovel in actual work. The traditional excavation resistance prediction regards the material as an ideal bulk material. In actual engineering, there are often large pieces of material buried in the material that cannot be fully predicted. The present method is used to dynamically judge and provide real-time feedback on the entire state of the excavation process, solving the problem that the excavation action cannot be fully executed due to inaccurate prediction in the past, and realizing closed-loop execution of automatic excavation;

[0081] 2. The automatic excavation method based on stall state recognition described in the present invention divides the bucket movement into two stages from the perspective of excavation technology: the first stage is the process of the bucket cutting into the material, and the second stage is to continuously cut and peel the material at an appropriate speed while maintaining the cutting depth. In combination with different stages, the operating state of the bucket is decomposed into physical characteristics, and these different motion characteristics will naturally appear with the state of the bucket. When constructing the solution, the current working state of the bucket is identified through the combination of the presented motion characteristics, so as to formulate targeted stall identification strategies according to different states, so as to achieve truly effective prediction and identification of stalls. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 It is a flow chart of a stall state identification execution module in the automatic mining method based on stall state identification of the present invention;

[0083] Figure 2 This is a schematic diagram of the bucket moving in a 2D plane without considering rotation;

[0084] Figure 3 It is a schematic diagram of the excavation trajectory obtained by fitting the automatic excavation method based on stall state recognition described in the present invention. DETAILED DESCRIPTION

[0085] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means any limitation to the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise specified, the relative arrangement, expressions and numerical values ​​of the components and steps described in these embodiments do not limit the scope of the present invention. The techniques, methods and equipment known to ordinary technicians in the relevant fields may not be discussed in detail, but in appropriate cases, the techniques, methods and equipment should be regarded as part of the specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0086] Example 1

[0087] The present invention obtains the motor's motion parameters such as torque, current and speed in real time through the lifting and pushing mechanism inverter; in addition, the excavation trajectory under the standard manual operation mode is introduced through data fitting, and the excavation trajectory is used to judge whether the current cutting-in angle of the bucket is reasonable, thereby effectively distinguishing the increase in load during normal excavation and the current, torque surge and speed drop caused by encountering large pieces of material or unreasonable excavation angles, thereby achieving accurate and effective stall identification on the basis of increasing the information dimension.

[0088] Specifically, the automatic mining method based on stall state recognition of the present invention includes:

[0089] The motion parameters of the bucket are obtained in real time, including the lifting speed of the bucket, the pushing speed of the bucket, the cutting angle θ of the bucket at the current position, and the torque and current of the lifting motor; wherein: the torque, current, speed of the lifting motor and the speed of the pushing motor are obtained in real time through the lifting and pushing mechanism inverters, and then the lifting speed is obtained by converting the speed of the lifting motor, and the pushing speed is obtained by converting the speed of the pushing motor. The cutting angle θ of the bucket at the current position is collected in real time by the saddle inclinometer installed on the saddle.

[0090] Determine whether the torque / current of the lifting motor is close to the preset torque limit / current limit, and record it as the first judgment result; calculate the bucket speed in real time based on the lifting speed of the bucket and the pushing speed of the bucket, and determine whether the calculated bucket speed exceeds the preset bucket speed critical value, and record it as the second judgment result; determine whether the cutting angle θ of the bucket at the current position is within the range of the preset optimal cutting angle θ0, and record it as the third judgment result;

[0091] The first to third judgment results are considered in coordination to determine whether the operating state of the bucket is in a stalled state, thereby controlling the specific working conditions of the lifting and pushing mechanisms.

[0092] Specifically, when the first to third judgment results indicate that the torque / current of the lifting motor approaches the preset torque limit / current limit, and the calculated bucket speed is within the preset bucket speed critical value, and the cutting angle θ of the bucket at the current position exceeds the range of the preset optimal cutting angle θ0, it indicates that the running state of the bucket is in the stalled rotor A state, and the first execution instruction is output to the lifting and pushing mechanisms respectively;

[0093] When the first to third judgment results indicate that the torque / current of the lifting motor approaches the preset torque limit / current limit, and the calculated bucket speed is within the preset bucket speed critical value, and the cutting angle θ of the bucket at the current position is within the preset optimal cutting angle θ0 range, it indicates that the running state of the bucket is in the stalled B state, and the second execution instruction is output to the lifting and pushing mechanisms respectively;

[0094] On the contrary, it indicates that the bucket is in a non-blocked state, and a third execution instruction is output to the lifting and pushing mechanisms respectively;

[0095] Under the control of the first execution command, the lifting and pushing mechanism stops lifting and appropriately retracts pushing to avoid large rocks on the excavation path or reduce excessive load caused by the bucket cutting too deep;

[0096] The lifting and pushing mechanisms, under the control of the second execution instruction, coordinately adjust the cutting angle of the bucket until the cutting angle θ of the bucket at the current position exceeds the range of the preset optimal cutting angle θ0, respectively judging whether the torque / current of the lifting motor of the bucket at the current position is close to the preset torque limit / current limit, and whether the bucket speed exceeds the preset bucket speed critical value; when the judgment result shows that the torque / current of the lifting motor is close to the preset torque limit / current limit, and the bucket speed is at the preset bucket speed critical value, respectively output the first execution instruction to the lifting and pushing mechanisms; when the judgment result shows that the torque / current of the lifting motor is close to the preset torque limit / current limit, and the bucket speed exceeds the preset bucket speed critical value, respectively output the third execution instruction to the lifting and pushing mechanisms;

[0097] The lifting and pushing mechanism maintains the current operating state of the bucket under the control of the third execution instruction.

[0098] Example 2

[0099] The automatic excavation method based on stall state recognition described in this embodiment divides the bucket movement into two stages from the perspective of excavation technology: the first stage is the process of the bucket cutting into the material, and the second stage is to continuously cut and peel the material at an appropriate speed while maintaining the cutting depth. In combination with different stages, the operating state of the bucket is decomposed into physical characteristics, and these different motion characteristics will naturally appear with the state of the bucket. When constructing the solution, the current working state of the bucket is identified through the combination of the presented motion characteristics, so as to formulate targeted stall identification strategies according to different states, so as to achieve truly effective prediction and identification of stalls.

[0100] Specifically, the automatic mining method based on stall state recognition described in this embodiment includes the following steps:

[0101] The physical characteristics of the bucket's current working state are calculated by the front-end computing module and transmitted to the stall state recognition execution module; the stall state recognition execution module recognizes whether there is a stall in the bucket's current working state through the received physical characteristics, and then plans a corresponding control strategy to control the working conditions of the lifting and pushing mechanisms.

[0102] in:

[0103] The front-end calculation module calculates the physical characteristics of the bucket's current working state through the real-time acquired motion parameters of the bucket; the physical characteristics of the bucket's current working state include at least one physical feature in the physical feature set; the bucket's motion parameters include the bucket's lifting speed, the bucket's pushing speed, the bucket's cutting angle θ at the current position, and the torque and current of the lifting motor.

[0104] The stall state recognition execution module is constructed through the following steps:

[0105] Step 1: Construct the physical feature set of the bucket:

[0106] After the physical characteristics of the bucket's operating state are decomposed, each physical characteristic is extracted to complete the construction of the bucket's physical characteristic set. The specific steps are as follows:

[0107] Step 1.1: Construct the optimal excavation trajectory and obtain the optimal cutting angle of the bucket:

[0108] Under the same material surface conditions, the saddle inclination angle θ during a single excavation in manual excavation mode is recorded by the PLC controller. t and push encoder value N t , denoted as (θ t ,N t ), the measurement frequency is 10Hz. The push encoder value is converted into the dipper arm extension through the structural parameters of the push mechanism itself. Without considering the rotation, the bucket moves in a 2D plane, so (θ t ,N t ) coordinates correspond to the fixed bucket tooth tip position (x, y), and the coordinate system is as follows Figure 2 shown.

[0109] For the convenience of calculation, a sixth-order polynomial is used to fit the excavation trajectory to obtain the fitting curve equation of the excavation trajectory as follows:

[0110] y=C6*x 6 +C5*x 5 +C4*x 4 +C3*x 3 +C2*x 2 +C1*x+C0;

[0111] In the formula: C1-C6 are the coefficients of each order polynomial; C0 is a constant; the effect after fitting is as follows Figure 3 As shown, this trajectory is regarded as the optimal mining trajectory at this time.

[0112] The optimal cut-in angle θ0 at any point A is obtained on the optimal excavation trajectory. The optimal cut-in angle θ0 is the angle between the tangent line at the point A and the x-axis, which is calculated by the following formula:

[0113] θ0=tan -1 (dy / dx)|x=X0;

[0114] Wherein: X0 represents the horizontal coordinate of site A.

[0115] Step 1.2: Construct a physical feature set:

[0116] In step 1.1, after solving the function expression of the optimal cutting angle θ0 during the bucket movement, a new discriminant dimension is provided for the decomposition of the physical characteristics of the bucket's operating state. Here, a physical feature set is established, which includes 3 physical features, corresponding to the first to third physical features, where:

[0117] First physical characteristic: the current / torque approaches the preset current / torque limit;

[0118] Second physical feature: the bucket speed is within a preset bucket speed critical value range.

[0119] Taking the shovel loading platform as the reference system, the bucket speed is calculated by the following formula:

[0120]

[0121] The second physical characteristic can be expressed as:

[0122]

[0123] Where: Indicates the bucket speed, Indicates the speed of improvement; Indicates the pushing speed; Indicates the bucket speed critical value.

[0124] The third physical feature: the angle θ between the bucket (dipper) and the horizontal direction is less than the optimal cutting angle θ0 at the current position, which can be expressed by the following formula: θ<θ0.

[0125] Step 2: Establishment of motion feature set:

[0126] Based on the three physical characteristics obtained above, the physical characteristics are freely combined to form several characteristic elements m i , which can form the bucket motion feature set M = {m1,m2,……,m i ,……m j}, j represents the total number of feature elements.

[0127] In the present invention, since the total number of physical features is 3, the total number of feature elements j≤7.

[0128] In addition, the present invention can combine the physical features in the following manner to form corresponding feature elements m: i :

[0129] Feature element m1: only includes the first physical feature;

[0130] Feature element m2: only includes the second physical feature;

[0131] Characteristic element m3: only includes the third physical characteristic;

[0132] Characteristic element m4: a combined characteristic consisting of the first physical characteristic a and the second physical characteristic b;

[0133] Characteristic element m5: a combination of the first physical characteristic a and the third physical characteristic c;

[0134] Characteristic element m6: a combined characteristic consisting of the second physical characteristic b and the third physical characteristic c;

[0135] Feature element m7: a combined feature consisting of the first physical feature a, the second physical feature b and the third physical feature c.

[0136] Step 3: Build the bucket state set:

[0137] The feature elements m included in the motion feature set constructed in step 2 i , reverse analysis of bucket states is performed one by one to realize bucket state recognition, and then bucket state set S = {s1, s2, ..., s i ,……s j}, in the bucket state set, the operation state s of each bucket i and each characteristic element m established in step 1 i One to one correspondence.

[0138] Given the 7 feature elements m constructed in the motion feature set in step 2 i The present invention can construct seven bucket operation states s one by one. i , as follows:

[0139] The bucket operation state s1 corresponds to the characteristic element m1. At this time, the bucket load is large, the bucket speed is large, and the cutting angle θ is greater than the optimal cutting angle θ0. There are two typical cases: one is that after the bucket is full of materials, the driver only operates the lifting mechanism to lift the bucket to reserve enough space for loading; the other is that the electric shovel continues to peel materials at a suitable cutting angle. The operation state of the bucket can be determined as a non-blocked state.

[0140] The bucket running state s2 corresponds to the characteristic element m2. At this time, the bucket is in a low speed state, but the load is small. The typical situation is that the bucket is in a stationary state or the bucket is in a low speed transition state during the movement process when the bucket is empty. It can be determined that the running state of the bucket is a non-blocked state.

[0141] The bucket running state s3 corresponds to the characteristic element m3; at this time, the bucket has speed but no load. A typical situation is that the bucket is in the process of empty bucket movement and the bucket has not cut into the material. It can be determined that the bucket's running state is a non-blocked state.

[0142] The bucket operation state s4 corresponds to the characteristic element m4; at this time, the bucket is in a high-load, low-speed motion state, and the cut-in angle is greater than the tangent angle corresponding to the optimal excavation trajectory at the current position. It can be determined that the bucket's operation state is in a stalled A state. The stalled A state means that the bucket runs at a low speed and high load (near the torque limit) at this moment while maintaining a reasonable cut-in angle, and after several seconds, the bucket speed remains at the bucket speed critical value. Below, the first physical feature a and the second physical feature b continue to exist.

[0143] The bucket running state s5 corresponds to the characteristic element m5. At this time, the bucket has a high load and a high speed. At this time, the bucket speed is not low, and the cut-in angle is less than the tangent angle of the corresponding trajectory. Therefore, the bucket has a certain speed component in the direction of the material. In addition, the load is high, so it can be considered that the bucket is cutting into the material (although the cut-in angle is unreasonable, there is speed, so no intervention is made in a short time). It is a preparatory action before effective excavation (the ideal excavation preparatory action is that the cut-in angle also changes along the tangent angle given by the optimal trajectory). Therefore, the running state of the bucket at this time can be determined as a non-blocked state.

[0144] The bucket operation state s6 corresponds to the characteristic element m6, and the bucket is in a light load state at this time. Therefore, the operation state of the bucket at this time can be determined as a non-blocked state.

[0145] The bucket running state s7 corresponds to the characteristic element m7. At this time, the bucket is in a high-load and low-speed state, and the cut-in angle is less than the tangent angle corresponding to the optimal excavation trajectory. A typical situation is that the bucket has penetrated deep into the pile, but the horizontal component of the movement direction is too large, resulting in neither effective excavation nor continuous movement of the bucket, and it is very easy to lift the boom and cause mechanical damage. Therefore, the running state of the bucket at this time can be determined as the stalled B state.

[0146] Step 4: Build a policy set:

[0147] For each bucket operation state s in the bucket state set S i , plan the corresponding control strategy p k, to form a strategy set P = {p1, p2, ..., p k ,……p m}, m represents the total number of control strategies in the strategy set. Specifically:

[0148] (1) Control strategy p1 is constructed for bucket operation states s1, s2, s3, and s6; the lifting and pushing mechanisms maintain the existing operation state of the bucket unchanged under the control of control strategy p1;

[0149] (2) Control strategy p2 is constructed for the bucket operation state s4; under the control of control strategy p2, the lifting and pushing mechanisms stop lifting and appropriately retract pushing to avoid large rocks on the excavation path or reduce excessive load caused by the bucket cutting too deep;

[0150] (3) Control strategy p3 is constructed for the bucket operation state s5. At this time, it is a transition state or the driver intends to use the bucket to push away the large rock in front. Therefore, the control strategy at this time is not to intervene and maintain the current operation state of the bucket unchanged;

[0151] (4) Control strategy p4 is constructed for the bucket operation state s7. Under the control of control strategy p4, the lifting and pushing mechanisms coordinately adjust the cutting angle of the bucket and trigger the front-end computing module to calculate the first to third physical characteristics in real time. After adjusting the cutting angle of the bucket, if the front-end computing module only outputs the first physical characteristic and the second physical characteristic to the stall state identification execution module, control strategy p2 is triggered. If the front-end computing module only outputs the first physical characteristic to the stall state identification execution module, control strategy p1 is triggered.

[0152] The ideal trajectory is established under a specific working condition. Its spatial scale is not universal, but its spatial relative relationship is universal. The bucket height is used as the equivalent benchmark between any trajectory and the ideal trajectory, that is, the cutting angle at a certain height of the optimal excavation trajectory can be universally applied to the cutting angle at any position when the bucket is at the same height. Based on this, the application expansion of any situation needs to be mapped to the ideal optimal excavation trajectory through equivalent transformation.

Claims

1. An automatic excavation method based on stall state recognition, characterized in that: include: Obtain the motion parameters of the bucket in real time, including the bucket lifting speed, bucket pushing speed, bucket cutting angle θ at the current position, and the torque and current of the lifting motor; Determine whether the torque / current of the lifting motor is close to the preset torque limit / current limit, and record it as the first determination result; Based on the lifting speed of the bucket and the pushing speed of the bucket, the bucket speed is calculated in real time, and it is determined whether the calculated bucket speed exceeds a preset bucket speed critical value, and recorded as a second determination result; Determine whether the cutting angle θ of the bucket at the current position is within the range of the preset optimal cutting angle θ0, and record it as the third determination result; The first to third judgment results are considered in coordination to determine whether the operating state of the bucket is in a stalled state, thereby controlling the specific working conditions of the lifting and pushing mechanisms.

2. The automatic excavation method based on stall state recognition according to claim 1 is characterized in that: When the first to third judgment results indicate that the torque / current of the lifting motor approaches the preset torque limit / current limit, and the calculated bucket speed is within the preset bucket speed critical value, and the cutting angle θ of the bucket at the current position exceeds the range of the preset optimal cutting angle θ0, it indicates that the running state of the bucket is in the stalled A state, and the first execution instruction is output to the lifting and pushing mechanisms respectively; When the first to third judgment results indicate that the torque / current of the lifting motor approaches the preset torque limit / current limit, and the calculated bucket speed is within the preset bucket speed critical value, and the cutting angle θ of the bucket at the current position is within the preset optimal cutting angle θ0 range, it indicates that the running state of the bucket is in the stalled B state, and the second execution instruction is output to the lifting and pushing mechanisms respectively; On the contrary, it indicates that the bucket is in a non-blocked state, and the third execution instruction is output to the lifting and pushing mechanisms respectively; under the control of the first execution instruction, the lifting and pushing mechanisms stop lifting and appropriately retract pushing to avoid large rocks on the excavation path or reduce excessive load caused by the bucket cutting too deep; The lifting and pushing mechanisms, under the control of the second execution instruction, coordinately adjust the cutting angle of the bucket until the cutting angle θ of the bucket at the current position exceeds the range of the preset optimal cutting angle θ0, respectively judging whether the torque / current of the lifting motor of the bucket at the current position is close to the preset torque limit / current limit, and whether the bucket speed exceeds the preset bucket speed critical value; when the judgment result shows that the torque / current of the lifting motor is close to the preset torque limit / current limit, and the bucket speed is at the preset bucket speed critical value, respectively output the first execution instruction to the lifting and pushing mechanisms; when the judgment result shows that the torque / current of the lifting motor is close to the preset torque limit / current limit, and the bucket speed exceeds the preset bucket speed critical value, respectively output the third execution instruction to the lifting and pushing mechanisms; The lifting and pushing mechanism maintains the current operating state of the bucket under the control of the third execution instruction.

3. The automatic excavation method based on stall state recognition according to claim 2 is characterized in that: The optimal cutting angle θ0 of the current bucket position is obtained by: Under the same material surface working conditions, the PLC controller records the saddle inclination angle θ of several groups of single excavation executions in the manual excavation mode. t and push encoder value N t , denoted as (θ t , N t ); The push encoder value is converted into the dipper arm extension through the structural parameters of the push mechanism itself. Without considering the bucket rotation, the bucket moves in a 2D plane. Therefore, each set of saddle inclination angle θ t and push encoder value N t The composition (θ t , N t ) coordinates correspond to the fixed bucket tooth tip position (x, y); The obtained bucket tooth tip position (x, y) is fitted using a sixth-order polynomial to obtain the fitting curve equation of the excavation trajectory as follows: y=C6*x 6 +C5*x 5 +C4*x 4 +C3*x 3 +C2*x 2 +C1*x+C0; Where: C1-C6 are the coefficients of polynomials of different orders; C0 is a constant; The fitting curve equation of the above excavation trajectory is the optimal excavation trajectory equation of the bucket; The optimal cut-in angle θ0 at any point A is obtained on the optimal excavation trajectory. The optimal cut-in angle θ0 is the angle between the tangent line at the point A and the x-axis, which is calculated by the following formula: θ0=tan -1 (dy / dx)|x=X0; Wherein: X0 represents the horizontal coordinate of site A.

4. An automatic excavation method based on stall state recognition, characterized in that: The steps include: The physical characteristics of the current working state of the bucket are calculated by the front-end calculation module and transmitted to the stall state identification execution module; The stall state recognition execution module recognizes whether there is a stall state in the current working state of the bucket through the received physical features, and then plans the corresponding control strategy to control the working conditions of the lifting and pushing mechanisms; The stall state recognition execution module is constructed through the following steps: Step 1: Construct the physical feature set of the bucket: After the physical characteristics of the bucket's operating state are decomposed, each physical characteristic is extracted to complete the establishment of the bucket's physical characteristic set; Step 2: Establishment of motion feature set: The physical features included in the physical feature set constructed in step 1 are freely combined to form several feature elements m i , The motion feature set M of the bucket can be constructed as follows: i ,......m j }, j represents the total number of characteristic elements; Step 3: Build the bucket state set: The feature elements m included in the motion feature set constructed in step 2 i , reverse analysis of bucket states is performed one by one to realize bucket state recognition, and bucket state set S = {s1, s2, ..., s i ,......s j }, in the bucket state set, the operation state s of each bucket i and each characteristic element m established in step 1 i One to one correspondence; Step 4: Build a policy set: For each bucket operation state s in the bucket state set S i , plan the corresponding control strategy p k , to form a strategy set P = {p1, p2, ..., p k ,......p m }, m represents the total number of control strategies in the strategy set.

5. The automatic excavation method based on stall state recognition according to claim 4 is characterized in that: The front-end calculation module calculates the physical characteristics of the current working state of the bucket through the motion parameters of the bucket obtained in real time; the physical characteristics of the current working state of the bucket include at least one physical characteristic in the physical characteristic set; The motion parameters of the bucket include the bucket lifting speed, the bucket pushing speed, the bucket cutting angle θ at the current position, and the torque and current of the lifting motor; In step 1, the physical feature set includes 3 physical features, corresponding to the first to third physical features, where: First physical characteristic: the current / torque approaches the preset current / torque limit; Second physical feature: the bucket speed is within a preset bucket speed critical value range; The third physical feature: the angle θ between the bucket and the horizontal direction is less than the optimal cutting angle θ0 of the bucket's current position.

6. The automatic excavation method based on stall state recognition according to claim 5 is characterized in that: The optimal cutting angle θ0 of the current bucket position is obtained by: Step 1.1: Construct the optimal excavation trajectory equation of the bucket: Step 1.1.1, under the same material surface working condition, record the saddle inclination angle θ of several groups of single excavation executions in the manual excavation mode through the PLC controller i and push encoder value N i , denoted as (θ i , N i ); Step 1.1.2: The push encoder value is converted into the dipper arm extension through the structural parameters of the push mechanism itself. Without considering the bucket rotation, the bucket moves in a 2D plane. Therefore, each set of saddle inclination angle θ i and push encoder value N i The composition (θ i , N i ) coordinates correspond to the fixed bucket tooth tip position (x, y); Step 1.1.3: Use a sixth-order polynomial to fit the obtained bucket tooth tip position (x, y) to obtain the fitting curve equation of the excavation trajectory as follows: y=C6*x 6 +C5*x 5 +C4*x 4 +C3*x 3 +C2*x 2 +C1*x+C0; Where: C1-C6 are the coefficients of polynomials of different orders; C0 is a constant; The fitting curve equation of the excavation trajectory is the optimal excavation trajectory equation of the bucket; Step 1.2: Obtain the optimal cut-in angle θ0 at any point A on the optimal mining trajectory. The optimal cut-in angle θ0 is the angle between the tangent line at point A and the x-axis, calculated by the following formula: θ0=tan -1 (dy / dx)|x=X0; Wherein: X0 represents the horizontal coordinate of site A.

7. The automatic excavation method based on stall state recognition according to claim 5 is characterized in that: The motion feature set constructed in step 2 includes each feature element m i , as follows: Feature element m1: only includes the first physical feature; Feature element m2: only includes the second physical feature; Characteristic element m3: only includes the third physical characteristic; Characteristic element m4: a combined characteristic consisting of the first physical characteristic and the second physical characteristic; Characteristic element m5: a combined characteristic consisting of the first physical characteristic and the third physical characteristic; Characteristic element m6: a combined characteristic consisting of the second physical characteristic and the third physical characteristic; Feature element m7: a combined feature consisting of the first physical feature, the second physical feature and the third physical feature.

8. The automatic excavation method based on stall state recognition according to claim 7, characterized in that: In step 3, the bucket operation state s of each bucket in the bucket state set S i The details are as follows: Bucket operation state s1, corresponding to characteristic element m1; Bucket operation state s2, corresponding to characteristic element m2; Bucket operation state s3, corresponding to characteristic element m3; Bucket operation state s4, corresponding to characteristic element m4; Bucket operation state s5, corresponding to characteristic element m5; Bucket operation state s6, corresponding to characteristic element m6; Bucket operating state s7 corresponds to characteristic element m7.

9. The automatic excavation method based on stall state recognition according to claim 8, characterized in that: Each control strategy p in the strategy set P k , specifically: The control strategy p1 is constructed for bucket operation states s1, s2, s3, and s6; the lifting and pushing mechanism maintains the existing operation state of the bucket unchanged under the control of the control strategy p1; Control strategy p2 is constructed for bucket operation state s4; under the control of control strategy p2, the lifting and pushing mechanism stops lifting and appropriately retracts pushing to avoid large rocks on the excavation path or reduce excessive load caused by the bucket cutting too deep; Control strategy p3 is constructed for bucket operation state s5; under the control of control strategy p3, the lifting and pushing mechanism maintains the existing operation state of the bucket unchanged; The control strategy p4 is constructed for the bucket operation state s7; under the control of the control strategy p4, the lifting and pushing mechanisms coordinately adjust the cutting angle of the bucket and trigger the front-end calculation module to calculate the first to third physical characteristics in real time; After adjusting the cutting angle of the bucket, if the front-end computing module only outputs the first physical feature and the second physical feature to the stall state identification execution module, the control strategy p2 is triggered; if the front-end computing module only outputs the first physical feature to the stall state identification execution module, the control strategy p1 is triggered.

10. An automatic excavation system based on stall status recognition, characterized in that: The invention comprises a device programmed to execute the automatic excavation method based on stall state identification as claimed in any one of claims 1 to 9.

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