Distributed multi-agent chain transmission control system and control method for scraper conveyor

Abstract

The invention discloses a distributed multi-agent chain transmission control system and method for a scraper conveyor. The transmission control system comprises a machine head intelligent body, a middle intelligent body, a machine tail intelligent body and a coal conveying part. The machine head intelligent body and the machine tail intelligent body only provide driving force of the motor, a chain tensioning system at the machine tail is omitted, and the space of a roadway is saved. The middle intelligent body comprises a motor driving system and a torsion tensioning system, the middle intelligent body can provide motor driving force, a chain tensioning force control system of the middle intelligent body is designed based on torsion and translation movement, and tensioning force control over a single-side chain or a double-end chain of the middle intelligent body can be achieved. The control method provided by the invention is a hierarchical control method based on multi-agent reinforcement learning, motor power balance and tension force control are combined, and stable coal conveying work of the scraper conveyor is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal transportation in fully mechanized mining working faces, and specifically relates to a distributed multi-intelligent chain transmission control system for a scraper conveyor and a control method thereof. Background Art

[0002] The scraper conveyor is the only coal transportation equipment in the fully mechanized mining face. The existing scraper conveyor adopts double-end motors at the head and tail to drive the chain and adopts the tail hydraulic system to adjust the chain tension.

[0003] Faced with the development trend of long transportation distance and large mining height, the amount of coal transported by the scraper conveyor will increase significantly, and the transportation of coal puts forward higher requirements on the motor drive and tensioning device of the scraper conveyor. The vibration generated by coal transportation will affect the power balance of the head and tail motors and the stable operation of the tail tensioning system, which may easily cause the scraper conveyor to malfunction and reduce the efficiency of coal mining; with the increase in the amount of coal transported, the power demand for the motor increases. If only the head and tail motors are used to provide driving force, the motor will be too large, increasing the area occupied by the motor in the roadway, forcing the need to mine a larger roadway, and the mining cost of the roadway is high, thus increasing the cost of coal mining.

[0004] The invention patent with publication number CN114394377A discloses a multi-point driven scraper conveyor synchronization control system, including a primary motor and a multi-stage motor group arranged between two primary motors, the primary motor and each motor in the multi-stage motor group are provided with a sprocket and a piezoelectric vibrator, the piezoelectric vibrator, the primary motor and each motor in the multi-stage motor group are connected to a computer, when the scraper conveyor is working, the piezoelectric vibrator sends a current intensity signal to the computer, the computer determines the working state of the scraper conveyor according to the current intensity signal, and controls the primary motor and each motor in the multi-stage motor group to work. The multi-point driven scraper conveyor synchronization control system can realize the graded start and stop of the scraper conveyor, reduce the overall tension borne by the scraper chain, and improve the reliability of the system working process.

[0005] The invention patent with the publication number CN116142695A discloses a long-distance non-equal strength three-drive high-efficiency energy-saving scraper conveyor device, including head sprocket I, head sprocket II, tail sprocket, head drive motor I, head drive motor II, tail drive motor, scraper chain, head torque sensor I, tail torque sensor, and motor control module. The motor control module is used to analyze and process the collected torque signal, and intelligently control the working state of the head drive motor II under different transportation conditions of the scraper conveyor, so that the scraper conveyor can transport materials efficiently and energy-savingly in different working states, reducing the power loss of the scraper conveyor.

[0006] The invention patent with publication number CN114394377A discloses a multi-point driven scraper conveyor synchronization control system, including a primary motor and a multi-stage motor group arranged between two primary motors, the primary motor and each motor in the multi-stage motor group are provided with a sprocket and a piezoelectric vibrator, the piezoelectric vibrator, the primary motor and each motor in the multi-stage motor group are connected to a computer, when the scraper conveyor is working, the piezoelectric vibrator sends a current intensity signal to the computer, the computer determines the working state of the scraper conveyor according to the current intensity signal, and controls the primary motor and each motor in the multi-stage motor group to work. The multi-point driven scraper conveyor synchronization control system can realize the graded start and stop of the scraper conveyor, reduce the overall tension borne by the scraper chain, and improve the reliability of the system working process.

[0007] The above existing technologies have solved the problem of long-distance scraper conveyors to a certain extent, but generally speaking, there are still some shortcomings: the amount of coal transported by the scraper conveyor continues to increase, and the elastic elongation of the chain will continue to increase. When the hydraulic tensioning system at the tail of the machine is used to supplement the elastic elongation of the chain, it will occupy the space of the tunnel and increase the mining cost of the tunnel. There is a coupling relationship between the power balance control of the motor and the tension control of the chain. They influence each other and jointly determine the stable operation of the coal transportation process. In the face of long-distance scraper conveyors, an appropriate method is needed to ensure the normal operation of the two systems. The above existing technologies do not take into account the problem of elastic elongation of the chain, and the coupling relationship between the power balance control of the motor and the tension control of the chain. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a distributed multi-agent chain transmission control system and control method for a scraper conveyor. The driving power required by the scraper conveyor is shared among multiple motors in a distributed manner, and the hydraulic tensioning device at the tail of the machine is eliminated. A multi-point hydraulic tensioning strategy is adopted to ensure stable coal transportation of the scraper conveyor.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: a distributed multi-agent chain transmission system of a scraper conveyor, comprising:

[0010] The head intelligent body is arranged at the head of the scraper conveyor, and includes a head permanent magnet motor, which is installed on the head frame, and the head permanent magnet motor drives the sprocket;

[0011] The tail intelligent body is arranged at the tail of the scraper conveyor, and includes a tail permanent magnet motor, which is installed on the tail frame and drives the sprocket;

[0012] The coal handling section consists of several middle troughs;

[0013] The intermediate intelligent body includes a motor drive system and a torsion tensioning system; two sets of intermediate intelligent bodies are respectively arranged at both ends of the middle of the scraper conveyor;

[0014] The motor drive system includes a middle permanent magnet motor, which drives the sprocket to rotate;

[0015] The torsional tensioning system is used to control the tensioning force, and includes a frame, a turntable, a torsional hydraulic motor, a tensioning wheel and a tensioning wheel shaft; the frame is fixedly connected to the middle transition frame and the middle groove respectively, the turntable is rotatably connected to the frame, the torsional hydraulic motor housing is fixedly connected to the frame, the torsional hydraulic motor output shaft is fixedly connected to the turntable, and drives the turntable to rotate; the tensioning wheel shaft is installed on the turntables on both sides, and the tensioning wheel is installed on the tensioning wheel shaft.

[0016] Furthermore, in the intermediate intelligent body, the motor drive system further comprises an intermediate transition frame, a first movable middle plate, a second movable middle plate, a first hydraulic cylinder and a second hydraulic cylinder;

[0017] The intermediate transition frame is rotatably connected to the first-level movable upper plate through the middle plate rotating shaft, one end of the first-level hydraulic cylinder is rotatably connected to the first-level movable upper plate, and the other end of the first-level hydraulic cylinder is rotatably connected to the intermediate transition frame. Under the drive of the first-level hydraulic cylinder, the first-level movable upper plate rotates around the middle plate rotating shaft;

[0018] The first movable upper plate is overlapped with the second movable middle plate, one end of the second hydraulic cylinder is rotatably connected to the first movable upper plate, and the other end of the second hydraulic cylinder is rotatably connected to the second movable upper plate. Driven by the second hydraulic cylinder, the second movable upper plate is extended and retracted along the movement direction of the chain, and the lower surface of the second movable upper plate is tangent to the sprocket shaft.

[0019] Further, in the intermediate intelligent body, the motor drive system further comprises a lower middle plate and a lower middle plate hydraulic cylinder;

[0020] One end of the lower middle plate is rotatably connected to the middle groove through the middle plate rotating shaft, one end of the lower middle plate hydraulic cylinder is rotatably connected to the lower middle plate, and the other end of the lower middle plate hydraulic cylinder is rotatably connected to the middle groove.

[0021] Furthermore, one end of the lower middle plate facing the machine head is an arc.

[0022] Further, in the intermediate intelligent body, the torsion tensioning system also includes a tensioning wheel slider and a tensioning wheel hydraulic cylinder;

[0023] Both sides of the tensioning wheel shaft are fixedly connected to the tensioning wheel sliders, and a tensioning wheel slideway is provided on the turntable, and the tensioning wheel slider slides inside the tensioning wheel slideway; one end of the tensioning wheel hydraulic cylinder is rotatably connected to the turntable, and the other end of the tensioning wheel hydraulic cylinder is rotatably connected to the tensioning wheel slider, and the tensioning wheel hydraulic cylinder is used to drive the tensioning wheel to move.

[0024] Another aspect of the present invention provides a distributed multi-agent chain transmission control method for a scraper conveyor, wherein the power balance control of the motor is defined as a primary agent, and the balance control of the tensioning force is defined as a secondary agent;

[0025] First, train the first-level agent separately, and then train the second-level agent based on the fixed first-level agent strategy;

[0026] In the initial stage, the first-level agent quickly optimizes the motor power distribution when the system starts;

[0027] In the stable stage, after the power output of the first level tends to be balanced, the second level agent gradually adjusts the tension to reduce the uneven force on the chain;

[0028] In the dynamic adjustment section, when the power state of the first level changes, the second level agent responds in real time and readjusts the tension.

[0029] Furthermore, when performing motor power balance control, the state space is the output power, current, speed, load change rate of each motor, and the real-time power difference between motors; the action space is to adjust the speed of each motor; the multi-agent version of deep deterministic policy gradient (MADDPG) is used to train it, and the reward function during training is:

[0030]

[0031] P i The actual output power of each motor; is the average power of all motors; N is the number of motors; C is the quantitative index of the feedback of chain tension fluctuation to power fluctuation; α and β are the weights of each item; where,

[0032]

[0033] k is the weight of tension fluctuation on reward, and v is the speed of the motor.

[0034] Furthermore, after the motor power training is completed, its strategy is fixed, and then the secondary agent is trained, namely the tension control; the state space is the tension state of the chain and the stress and strain data of each tensioning point; the action space is to adjust the torsion angle of each intermediate agent or the extension and contraction amount of the tension wheel hydraulic cylinder; the MAPPO algorithm is used to train it, and the reward function is:

[0035]

[0036] Among them, τj is the actual tensioning force of the jth tensioning point. The tensioning points are all the meshing and separation points of the sprocket and the chain. τ* is the desired target value, which can be selected according to the actual situation. V is the variance of the chain tensioning force, which is used to measure the dynamic tension variation range of each tensioning point in the chain. α, β, and γ are the weight values ​​of each item.

[0037] Compared with the prior art, the technical effects of the present invention include:

[0038] (1) The hydraulic tensioning system at the tail of the machine was cancelled and distributed chain tensioning was adopted, which reduced the area occupied by the tunnel and reduced the mining cost.

[0039] (2) Based on the combination of torsion and translation, a tensioning system structure is designed, which can tension the chains on both sides of the intermediate intelligent body simultaneously or perform unilateral tensioning.

[0040] (3) A hierarchical motor drive power balance and chain tension force coordinated control strategy is proposed. This strategy is also applicable to the structure of the head and tail double-end motor drive and tail hydraulic chain tensioning system in the current scraper conveyor, which can ensure the stable coal transportation of the scraper conveyor.

[0041] (4) The control of motor drive and chain tension is realized based on a multi-agent deep reinforcement learning algorithm. The coordinated control of different fields is achieved through continuous data training, which can reduce the difficulty of control system development and multidisciplinary coupling control. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The present invention is a schematic diagram of the overall structure of the scraper conveyor;

[0043] Figure 2 It is a schematic diagram of the structure of the head intelligent body of the present invention;

[0044] Figure 3 It is a schematic diagram of the structure of the tail intelligent body of the present invention;

[0045] Figure 4 It is a schematic diagram of the structure of the intermediate intelligent agent of the present invention;

[0046] Figure 5 The local structure of the intermediate agent of the present invention is shown as follows Figure 1 ;

[0047] Figure 6 The local structure of the intermediate agent of the present invention is shown as follows Figure 2 ;

[0048] Figure 7 The local structure of the intermediate agent of the present invention is shown as follows Figure 3 ;

[0049] Figure 8 The local structure of the intermediate agent of the present invention is shown as follows Figure 4 .

[0050] In the figure, 1-head intelligent agent, 2-middle intelligent agent, 3-tail intelligent agent, 4-coal transport section;

[0051] 101-head permanent magnet motor, 102-head frame;

[0052] 201-middle transition frame, 202-frame, 203-turntable, 204-first movable middle plate, 205-second movable middle plate, 206-tensioning wheel, 207-tensioning wheel shaft, 208-tensioning wheel slider, 209-middle plate rotating shaft, 210-lower middle plate, 211-first hydraulic cylinder, 212-second hydraulic cylinder, 213-torsion hydraulic motor, 214-middle permanent magnet motor, 215-tensioning wheel hydraulic cylinder, 216-lower middle plate hydraulic cylinder;

[0053] 301- tail permanent magnet motor, 302- tail frame;

[0054] 401-middle groove, 402-chain, 403-scraper, 404-sprocket, 405-sprocket shaft. DETAILED DESCRIPTION

[0055] In order to make those skilled in the art better understand the present invention, the present invention is further clearly and completely described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the features in the embodiments and examples of this application can be combined with each other.

[0056] A typical embodiment of the present invention provides a distributed multi-agent chain transmission system for a scraper conveyor, such as Figure 1 As shown, it includes a head intelligent body 1, a middle intelligent body 2, a tail intelligent body 3 and a coal conveying part 4, which can be assembled according to different coal conveying lengths and requirements to form a scraper conveyor of different lengths. This embodiment distributes the driving power required by the scraper conveyor to multiple motors, cancels the hydraulic tensioning device at the tail, and adopts a multi-position hydraulic tensioning strategy.

[0057] The head intelligent body 1 is arranged at the head of the scraper conveyor. Figure 2 As shown, the head intelligent body 1 includes a head permanent magnet motor 101, which is installed on a head frame 102. The head permanent magnet motor 101 drives the sprocket 404, and then drives the chain 402 and the scraper 403 to transport coal.

[0058] The tail intelligent body 3 is arranged at the tail of the scraper conveyor. Figure 3As shown, the tail intelligent body 3 includes a tail permanent magnet motor 301, which is installed on a tail frame 302. The tail permanent magnet motor 201 drives the sprocket 404, which in turn drives the chain 402 and the scraper 403 to transport coal.

[0059] The coal conveying section 4 is composed of a plurality of middle grooves 401. Different numbers of middle grooves 401 form scraper conveyors of different lengths, and provide a running track for the coal mining machine to cut the coal wall.

[0060] The intermediate intelligent body 2 includes a motor drive system and a torsion tension system. Figure 1 As shown, two sets of intermediate intelligent bodies are respectively arranged at the two ends of the middle part of the scraper conveyor.

[0061] The motor drive system includes a middle permanent magnet motor 214 , and the middle permanent magnet motor 214 drives the sprocket 404 to rotate.

[0062] In a preferred embodiment, the motor drive system further includes an intermediate transition frame 201 , a primary movable middle plate 204 , a secondary movable middle plate 205 , a primary hydraulic cylinder 211 and a secondary hydraulic cylinder 212 .

[0063] like Figure 5 As shown, the intermediate transition frame 201 is rotationally connected to the first-level movable middle plate 204 through the middle plate rotating shaft 209, one end of the first-level hydraulic cylinder 211 is rotationally connected to the first-level movable middle plate 204, and the other end of the first-level hydraulic cylinder 211 is rotationally connected to the intermediate transition frame 201. Under the drive of the first-level hydraulic cylinder 211, the first-level movable middle plate 204 rotates around the middle plate rotating shaft 209.

[0064] like Figure 6 As shown, the primary movable middle plate 204 overlaps the secondary movable middle plate 205, one end of the secondary hydraulic cylinder 201 is rotatably connected to the primary movable middle plate 204, and the other end of the secondary hydraulic cylinder 201 is rotatably connected to the secondary movable middle plate 205. Driven by the secondary hydraulic cylinder 212, the secondary movable middle plate 205 can be extended and retracted along the moving direction of the chain 402, and the lower surface of the secondary movable middle plate 205 is tangent to the sprocket shaft 405. The torsion tensioning system can provide a closed conveying bottom plate for the scraper during rotation to prevent coal from falling.

[0065] In another preferred embodiment, the motor drive system further includes a lower middle plate 210 and a lower middle plate hydraulic cylinder 216 .

[0066] like Figure 5As shown, one end of the lower middle plate 210 is rotatably connected to the middle groove 401 through the middle plate rotating shaft 209, one end of the lower middle plate hydraulic cylinder 216 is rotatably connected to the lower middle plate 210, and the other end of the lower middle plate hydraulic cylinder 216 is rotatably connected to the middle groove 401. The lower middle plate 210 can be rotated at different angles by the extension and contraction of the lower middle plate hydraulic cylinder 216. The end of the lower middle plate 210 facing the machine head is an arc, which can prevent coal from falling to the bottom when transporting coal.

[0067] The middle permanent magnet motor 214 drives the sprocket 404 to rotate, and then drives the chain 402 and the scraper 403 to transport the coal. When the chain 402 passes through the middle intelligent body, it first passes through the middle transition frame 201, and then passes through an "S"-shaped path, and then returns to the middle groove 401. After passing through the sprocket 404, the coal directly falls into the lower middle groove 401 without passing through the tension wheel 206.

[0068] The torsional tensioning system is used to control the tensioning force, and the torsional tensioning system includes a frame 202 , a rotating disk 203 , a torsional hydraulic motor 213 , a tensioning wheel 206 and a tensioning wheel shaft 207 .

[0069] like Figure 4 As shown, the frame 202 is fixedly connected to the intermediate transition frame 201 and the middle slot 401 respectively, providing support for the intermediate intelligent body. The turntable 203 is rotatably connected to the frame 202, the housing of the torsion hydraulic motor 213 is fixedly connected to the frame 202, the output shaft of the torsion hydraulic motor 213 is fixedly connected to the turntable 203, driving the turntable 203 to rotate, the tensioning wheel shaft 207 is installed on the turntables 203 on both sides, and the tensioning wheel 206 is installed on the tensioning wheel shaft 207. When the turntable 203 rotates clockwise, the chains 402 on both sides thereof are tensioned at the same time.

[0070] In a preferred embodiment, the torsional tensioning system further includes a tensioning wheel slider 208 and a tensioning wheel hydraulic cylinder 215 .

[0071] like Figure 6 , Figure 7 As shown, both sides of the tension wheel shaft 207 are fixedly connected to the tension wheel slider 208, and the rotating disk 203 is provided with a tension wheel slideway, and the tension wheel slider 203 slides inside the tension wheel slideway, thereby adjusting the chain tension on one side of the tension wheel 206 separately. Figure 8 As shown, one end of the tensioning wheel hydraulic cylinder 215 is rotatably connected to the turntable 203, and the other end of the tensioning wheel hydraulic cylinder 215 is rotatably connected to the tensioning wheel slider 208. The tensioning wheel hydraulic cylinder 215 is used to drive the tensioning wheel 206 to move.

[0072] Another typical embodiment of the present invention provides a control method based on the above-mentioned distributed multi-agent chain transmission system of the scraper conveyor,

[0073] This embodiment adopts a hierarchical control strategy based on multi-agent reinforcement learning, defining motor power balance control as a primary agent and tension force balance control as a secondary agent.

[0074] First, the first-level agent is trained separately to ensure that its power allocation strategy is optimized. Based on the fixed first-level agent strategy, the second-level agent is trained to reduce learning interference.

[0075] In the initial stage, the first-level intelligent agent quickly optimizes the motor power distribution when the system starts; in the stable stage, after the first-level power output tends to be balanced, the second-level intelligent agent gradually adjusts the tension to reduce uneven force on the chain; dynamic adjustment, when the first-level power state changes, the second-level intelligent agent responds in real time and readjusts the tension.

[0076] When performing motor power balance control, the state space is the output power, current, speed, load change rate of each motor, and the real-time power difference between motors. The action space is to adjust the speed of each motor. The multi-agent version of deep deterministic policy gradient (MADDPG) is used for training.

[0077] First, the advantage function is calculated at each time step using the generalized advantage estimation (GAE)

[0078] Among them, δ t =R t +γ×V(S t+1 )-V(S t ).

[0079] Then, calculate the cumulative discounted reward G t : G t =R t +γ×R t+1 +γ 2 ×R t+2 +…, where the reward function is:

[0080]

[0081] P i The actual output power of each motor; is the average power of all motors; N is the number of motors; C is the quantitative index of the feedback of chain tension fluctuation to power fluctuation; α and β are the weights of each item; where,

[0082]

[0083] k is the weight of tension fluctuation on reward, and v is the speed of the motor.

[0084] Use the clipping objective function for policy optimization and convert the advantage function Bring in

[0085]

[0086] Among them, r t (θ) is the ratio of the current policy to the old policy, and ∈ is a hyperparameter that limits the magnitude of policy updates.

[0087] Use the mean squared error loss function to optimize the value network:

[0088]

[0089] Among them G t is the cumulative discounted reward calculated. Using the Adam optimization algorithm, the loss function is minimized and the accuracy of system control is gradually improved.

[0090] After the motor power training is completed, its strategy is fixed, and then the secondary agent, namely the tension control, is trained. State space: the tension state of the chain, the stress and strain data of each tension point; action space: adjust the torsion angle of each intermediate agent or the extension and contraction of the tension wheel hydraulic cylinder. The MAPPO algorithm is used for training.

[0091] First, the advantage function is calculated at each time step using the generalized advantage estimation (GAE)

[0092] Among them, δ t =R t +γ×V(S t+1 )-V(S t ).

[0093] Then, calculate the cumulative discounted reward G t : G t =R t +γ×R t+1 +γ 2 ×R t+2 +…, the reward function is:

[0094]

[0095] Among them, τj is the actual tensioning force of the jth tensioning point. The tensioning points are all the meshing and separation points of the sprocket and the chain. τ* is the desired target value, which can be selected according to the actual situation. V is the variance of the chain tensioning force, which is used to measure the dynamic tension variation range of each tensioning point in the chain. α, β, and γ are the weight values ​​of each item.

[0096] Use the clipping objective function for policy optimization and convert the advantage function Bring in

[0097]

[0098] Among them, r t (θ) is the ratio of the current policy to the old policy, and ∈ is a hyperparameter that limits the magnitude of policy updates.

[0099] Use the mean squared error loss function to optimize the value network:

[0100] L(φ)=E[(V φ (S t )-G t ) 2 ]

[0101] Among them, Gt is the calculated cumulative discounted reward. Using the Adam optimization algorithm, the loss function is minimized and the accuracy of system control is gradually improved.

[0102] The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A distributed multi-agent chain transmission system for a scraper conveyor, characterized in that: include: The head intelligent body is arranged at the head of the scraper conveyor, and includes a head permanent magnet motor, which is installed on the head frame, and the head permanent magnet motor drives the sprocket; The tail intelligent body is arranged at the tail of the scraper conveyor, and includes a tail permanent magnet motor, which is installed on the tail frame and drives the sprocket; The coal handling section consists of several middle troughs; The intermediate intelligent body includes a motor drive system and a torsion tensioning system; two sets of intermediate intelligent bodies are respectively arranged at both ends of the middle of the scraper conveyor; The motor drive system includes a middle permanent magnet motor, which drives the sprocket to rotate; The torsional tensioning system is used to control the tensioning force, and includes a frame, a turntable, a torsional hydraulic motor, a tensioning wheel and a tensioning wheel shaft; the frame is fixedly connected to the middle transition frame and the middle groove respectively, the turntable is rotatably connected to the frame, the torsional hydraulic motor housing is fixedly connected to the frame, the torsional hydraulic motor output shaft is fixedly connected to the turntable, and drives the turntable to rotate; the tensioning wheel shaft is installed on the turntables on both sides, and the tensioning wheel is installed on the tensioning wheel shaft.

2. The distributed multi-agent chain transmission control system for a scraper conveyor according to claim 1 is characterized in that: In the intermediate intelligent body, the motor drive system further includes an intermediate transition frame, a first-level movable middle plate, a second-level movable middle plate, a first-level hydraulic cylinder and a second-level hydraulic cylinder; The intermediate transition frame is rotatably connected to the first-level movable upper plate through the middle plate rotating shaft, one end of the first-level hydraulic cylinder is rotatably connected to the first-level movable upper plate, and the other end of the first-level hydraulic cylinder is rotatably connected to the intermediate transition frame. Under the drive of the first-level hydraulic cylinder, the first-level movable upper plate rotates around the middle plate rotating shaft; The first movable upper plate is overlapped with the second movable middle plate, one end of the second hydraulic cylinder is rotatably connected to the first movable upper plate, and the other end of the second hydraulic cylinder is rotatably connected to the second movable upper plate. Driven by the second hydraulic cylinder, the second movable upper plate is extended and retracted along the movement direction of the chain, and the lower surface of the second movable upper plate is tangent to the sprocket shaft.

3. The distributed multi-agent chain transmission control system for a scraper conveyor according to claim 2 is characterized in that: In the intermediate intelligent body, the motor drive system further comprises a lower middle plate and a lower middle plate hydraulic cylinder; One end of the lower middle plate is rotatably connected to the middle groove through the middle plate rotating shaft, one end of the lower middle plate hydraulic cylinder is rotatably connected to the lower middle plate, and the other end of the lower middle plate hydraulic cylinder is rotatably connected to the middle groove.

4. The distributed multi-agent chain transmission control system for a scraper conveyor according to claim 3 is characterized in that: One end of the lower middle plate facing the machine head is an arc.

5. The distributed multi-agent chain transmission control system for a scraper conveyor according to claim 1 or 4, characterized in that: In the intermediate intelligent body, the torsion tensioning system also includes a tensioning wheel slider and a tensioning wheel hydraulic cylinder; Both sides of the tensioning wheel shaft are fixedly connected to the tensioning wheel sliders, and a tensioning wheel slideway is provided on the turntable, and the tensioning wheel slider slides inside the tensioning wheel slideway; one end of the tensioning wheel hydraulic cylinder is rotatably connected to the turntable, and the other end of the tensioning wheel hydraulic cylinder is rotatably connected to the tensioning wheel slider, and the tensioning wheel hydraulic cylinder is used to drive the tensioning wheel to move.

6. The distributed multi-agent chain transmission control method for a scraper conveyor according to claim 1 is characterized in that: The power balance control of the motor involved in claims 1-5 is defined as a primary intelligent agent, and the balance control of the tensioning force involved in claims 1-5 is defined as a secondary intelligent agent; First, train the first-level agent separately, and then train the second-level agent based on the fixed first-level agent strategy; In the initial stage, the first-level agent quickly optimizes the motor power distribution when the system starts; In the stable stage, after the power output of the first level tends to be balanced, the second level agent gradually adjusts the tension to reduce the uneven force on the chain; In the dynamic adjustment section, when the power state of the first level changes, the second level agent responds in real time and readjusts the tension.

7. The distributed multi-agent chain transmission control method for a scraper conveyor according to claim 6 is characterized in that: When performing motor power balance control, the state space is the output power, current, speed, load change rate of each motor, and the real-time power difference between motors; the action space is to adjust the speed of each motor; the multi-agent version of deep deterministic policy gradient (MADDPG) is used for training, and the reward function during training is: P i The actual output power of each motor; is the average power of all motors; N is the number of motors; C is the quantitative index of the feedback of chain tension fluctuation to power fluctuation; α and β are the weights of each item; where, k is the weight of tension fluctuation on reward, and v is the speed of the motor.

8. The distributed multi-agent chain transmission control method for a scraper conveyor according to claim 7 is characterized in that: After the motor power training is completed, its strategy is fixed, and then the secondary agent is trained, namely the tension control; the state space is the tension state of the chain and the stress and strain data of each tensioning point; the action space is to adjust the torsion angle of each intermediate agent or the extension and contraction amount of the tension wheel hydraulic cylinder; the MAPPO algorithm is used to train it, and the reward function is: Among them, τj is the actual tensioning force of the jth tensioning point. The tensioning points are all the meshing and separation points of the sprocket and the chain. τ* is the desired target value, which can be selected according to the actual situation. V is the variance of the chain tensioning force, which is used to measure the dynamic tension variation range of each tensioning point in the chain. α, β, and γ are the weight values ​​of each item.

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