A self-propelled forward movement control method for hydraulic supports based on the lever torque principle

Abstract

This invention discloses a self-propelled forward movement control method for hydraulic supports based on the lever torque principle, relating to the field of hydraulic support movement control technology. In inclined coal seam working faces, this method solves the technical problems of easily damaged jacks and low moving efficiency caused by excessive moving resistance. The technical solution of this invention is as follows: The hydraulic support is moved forward in a self-propelled manner according to the following steps: S1: Setting the angle of the inclined reference plane; S2: Pre-pushing and stabilizing the base; S3: Differentiated extension and attitude adjustment of the column; S4: Force-driven self-propelling and forward movement execution; S5: Reset and support restoration. This invention cleverly transforms the enormous vertical pressure of the roof into the main driving force for the support's forward movement, significantly reducing moving resistance and improving the level of automation and equipment lifespan.

Description

Technical Field

[0001] This invention relates to the field of hydraulic support movement control technology, and more particularly to a control method for realizing the self-propelled forward movement of hydraulic supports in inclined coal seam fully mechanized mining faces by using roof pressure as the active driving force, belonging to the field of mining machinery automation technology. Background Technology

[0002] As coal mining in my country expands into deeper and more complex geological conditions, mining inclined coal seams, especially in steeply inclined overhead faces, has become one of the core technological challenges in ensuring energy supply. In such faces, the coal mining machine cuts along the inclined coal seam from bottom to top, while the hydraulic supports, as the core equipment of the working face, must keep pace with the mining machine, continuously moving forward towards the coal wall (i.e., diagonally upward) to maintain roof stability and ensure operational safety. However, this unique mining method has led to a high-energy-consuming and high-risk technical dilemma in the support-moving operation.

[0003] During the mining process in the overhead face, the enormous vertical pressure of the overlying strata (i.e., roof working resistance) constantly acts on the top beam of the hydraulic support, constituting the main external load for support movement. Traditional hydraulic support pushing methods rely entirely on pushing jacks installed between the base and the scraper conveyor to provide horizontal thrust. This thrust must overcome not only the friction between the base and the bottom plate, the magnitude of which is directly related to the vertical pressure of the roof, but also the additional resistance between the top beam and the roof. When the roof pressure is enormous and the coal seam dip angle is large, these resistances increase dramatically, forcing the pushing jacks to output extremely high thrust. This places stringent requirements on the strength and sealing of components such as the jacks, hydraulic valve groups, and pipelines, leading to frequent equipment failures, high maintenance costs, and a situation of low energy efficiency and drastically increased operating pressure in the entire hydraulic system.

[0004] Even more serious is the fact that, under the combined mechanical environment of immense roof pressure and the working face's own weight, the traditional "rigid resistance" mode of moving control is highly susceptible to a series of safety accidents. When the moving force is insufficient to overcome the enormous resistance, the supports are prone to mutual squeezing, leading to "support squeezing" or "support biting," causing the working face to stagnate. Under the continuous action of roof pressure and lateral forces, the supports are highly prone to instability, tilting, or even "collapse" during the moving process, not only completely losing their supporting capacity but also potentially causing devastating damage to equipment and personnel. Furthermore, existing moving technologies generally lack real-time perception and intelligent response capabilities to changes in working conditions such as roof pressure. The control methods are crude, and the stability of the support movement is highly dependent on the operator's personal experience. The level of automation and intelligence lags far behind the construction requirements of modern, high-yield, and high-efficiency working faces.

[0005] In fact, the fundamental problem with existing hydraulic support moving technology in overhead mining faces lies in its complete reliance on built-in mechanical power to passively resist enormous external natural loads. This is a rigid confrontation mode of "the weak overcoming the strong," resulting in huge moving resistance, severe equipment wear and tear, and prominent safety risks. Therefore, how to break through the constraints of traditional technical routes and explore a new control method that can "use the force against the enemy" and "transform force into movement," that is, cleverly convert the vertical pressure of the roof into effective power for the forward movement of auxiliary supports, thereby significantly reducing moving resistance and improving operational safety and intelligence, has become a key scientific problem that urgently needs to be solved in the current mining equipment field. This is also the core technical challenge that this invention aims to address. Summary of the Invention

[0006] To address the above problems, this invention proposes a self-propelled forward movement control method for hydraulic supports based on the lever torque principle. This method can solve the technical problems of easy damage to the pushing jacks and low pushing efficiency caused by excessive pushing resistance during the working process of inclined coal seams.

[0007] The technical solution of this invention is as follows: The hydraulic support is moved forward in a self-propelled manner according to the following steps:

[0008] S1: Setting the angle of the inclined reference plane;

[0009] In the early stage of mining, the dip angle of the coal seam is measured, and the angle of the inclination reference surface of the working face is dynamically set based on the dip angle. The angle of the inclination reference surface satisfies the relationship (1) to ensure that a stable reference surface with an inclination angle of γ is formed along the advancing direction of the working face.

[0010] γ = m × β (1)

[0011] Where m is a proportionality coefficient ranging from 0.1 to 0.4;

[0012] S2: Pre-push to stabilize the base;

[0013] When the hydraulic support needs to move forward toward the coal wall (4), the support controller first issues an instruction to operate multiple columns of the support to simultaneously perform small-amplitude column lowering operations, so that a uniform and controllable gap is formed between the support top beam (8) and the roof rock layer (7); then, the support push jack (3) is operated to apply a short-term, small pre-push or pre-tension force to the support base (10);

[0014] S3: Differentiated column elongation and posture adjustment;

[0015] Multiple columns of the hydraulic support are operated asynchronously and differentially to elongate, resulting in an elongation ΔL of the column (1) closest to the coal face. m The elongation ΔL is greater than that of the support column (2) on the side closer to the goaf. cThis causes the top beam (8) and base (10) of the support to change from their original posture to a preset tilted posture that is higher in the front and lower in the back; through this asynchronous and differentiated operation, the support base generates a preset elevation angle φ.

[0016] When the support forms an inclined posture with the front higher than the back, the huge vertical pressure F of the top plate acts on the rear of the top beam. The pressure (12) of the top plate rock layer (7) on the top beam (8) is used as the load force. A stable instantaneous glue point (5) is formed in the contact area between the rear of the support base (10) and the bottom plate (11). At this time, the pressure (12) of the top plate forms a long lever arm relative to the instantaneous glue point (5), which creates a strong clockwise forward tilting moment and provides the main driving force for self-propelled movement.

[0017] S4: Self-propelled and forward-moving execution;

[0018] Under the mechanical structure formed in step S3, the operating push jack (3) applies a pulling force pointing towards the coal wall; this pulling force forms a counterclockwise balancing torque relative to the instantaneous adhesive point (5) in S3. The main function of this pulling force is to overcome the friction between the base (10) and the bottom plate (11) and trigger a clockwise forward tilting torque driven by the top plate pressure (12). The entire support then moves forward in the expected rolling manner around the instantaneous adhesive point (5) along the slope direction of the working face until the support moves to the predetermined position.

[0019] S5: Reset and support restoration;

[0020] Once the support frame is in place, the controller instructs all columns to extend synchronously until they return to their original support state. The rear of the top beam then re-engages tightly with the top plate, returning to its original support state and reaching the rated initial support force, thus completing one full cycle of support frame forward movement.

[0021] In step S3, the control of the differential expansion and contraction of the support pillars is dynamically calculated based on the current actual coal seam dip angle of the overhead mining face. The control formula is as follows:

[0022] (ΔL) m – ΔL c = D × tan(β) (2)

[0023] Among them, (ΔL) m – ΔL c ) represents the difference in column expansion and contraction, and D is 0.8 to 1.2 times the center distance between the columns near the coal face and the columns near the goaf.

[0024] The difference in initial elongation between the column near the coal face and the column near the goaf and the width W of the support base satisfy the following relationship: 0.01W ≤ (ΔL) m – ΔLc ≤ 0.1W.

[0025] The preset elevation angle φ ranges from 1.0° to 4.0°.

[0026] The instantaneous adhesive point is not a physical structure, but refers to a contact area that is mechanically stable and serves as a torque fulcrum, where the rear of the base and the bottom plate generate a large contact pressure due to the pressure of the top plate after the bracket is adjusted.

[0027] In step S3, the control of the differential expansion and contraction of the support pillars is dynamically calculated based on the current actual coal seam dip angle of the overhead mining face. The control formula is as follows:

[0028] (ΔL) m – ΔL c = D × tan(β) (2)

[0029] Among them, (ΔL) m – ΔL c ) represents the difference in column expansion and contraction, and D is 0.8 to 1.2 times the center distance between the columns near the coal face and the columns near the goaf.

[0030] Step S3 also includes a real-time dynamic correction process based on pressure feedback, which is implemented using a closed-loop control algorithm based on angular step increments, as follows:

[0031] A pressure sensor installed at the rear of the support beam monitors the pressure (P) of the top plate on the rear of the top beam in real time; when the pressure (P) exceeds the preset standard working pressure (P0), the preset elevation angle (φ) is automatically increased, and the preset elevation angle (φ) is determined by the following step adjustment formula (3):

[0032] φ = φ0 + (n-1) × Δφ (3)

[0033] Wherein, φ0 is the basic elevation angle, Δφ is the angular step increment value, and its value ranges from 0.1° to 0.5°; n represents the excess multiple of pressure P relative to P0, which is calculated by n = floor(P / P0), where floor indicates rounding down the result. The basic elevation angle φ0, standard working pressure P0, and angular step increment Δφ are all parameters that are pre-calibrated and stored in the support controller based on the support model, roof lithology grade, and working face mining experience.

[0034] During the execution of the real-time dynamic correction step, the controller also monitors the pressure changes in the column cavity. When it detects that the column pressure rises sharply due to the increase in elevation angle and approaches its safe working threshold, it issues a warning or automatically stops the current attitude adjustment.

[0035] This invention aims to solve the technical problems of high resistance, low efficiency, and easy equipment damage in the movement of hydraulic supports in inclined coal seams (especially in overhead mining faces). First, an inclined reference plane is established at the working face. When the support needs to be moved forward, the base is stabilized by pre-pushing. Differential elongation of the support column is performed to create a preset "front-high, rear-low" inclined posture. The roof pressure forms a momentary mechanical bonding point at the contact area between the rear of the base and the bottom plate, acting as a fulcrum and generating a strong forward tilting torque. Finally, a small pulling force against friction is applied by operating the pushing jack as the trigger force, which leverages the lever effect to drive the support forward efficiently to the predetermined position via a rolling motion, completing the support reset. This invention cleverly transforms the enormous vertical pressure of the roof into the main driving force for the support's forward movement, significantly reducing the moving resistance and improving the level of automation and equipment lifespan. Compared with existing technologies, this invention has the following significant advantages:

[0036] I. This invention innovatively utilizes the lever torque principle to convert the enormous vertical pressure F of the top plate into the main driving torque for moving the support forward, completely changing the previous mode of using push jacks to "confront" enormous resistance. The push jack only needs to provide a small trigger pull to overcome friction to pry the entire support, greatly reducing the required pushing force and effectively solving the problem of easy damage to push jacks.

[0037] Second, due to the significant reduction in pushing resistance, the forward movement of the support is smoother and faster. Combined with a closed-loop control algorithm based on pressure feedback, the system can adaptively adjust the support posture according to the actual roof pressure, achieving intelligent control, reducing reliance on operator experience, and improving the automation and intelligence level of the entire working face.

[0038] Third, by turning the roof pressure into a benefit, the severe stress during the pushing process is reduced, effectively avoiding serious accidents such as "roof squeezing," "roof biting," and "roof collapse" caused by insufficient pushing force or uneven stress, and greatly improving the mining safety of inclined coal seam working faces.

[0039] Fourth, the reduction in the overall workload of the pushing system and hydraulic system means that the stress on each hydraulic component, pipeline and structural component is significantly reduced, which effectively slows down equipment fatigue damage, greatly extends the service life of hydraulic supports and their core components, and reduces the production and maintenance costs of the mine. Attached Figure Description

[0040] Figure 1 This is a complete flowchart of the control method described in this invention.

[0041] Figure 2 This is a schematic diagram illustrating the mechanical principle of the hydraulic support described in this invention under attitude adjustment and self-propelled states.

[0042] In the diagram: 1-Side pillar near the coal face; 2-Side pillar near the goaf; 3-Pushing jack; 4-Coal face; 5-Instantaneous cementation point; 6-Forward probe beam; 7-Roof strata; 8-Roof beam; 9-Support gravity; 10-Base; 11-Bottom plate; 12-Roof pressure; 13-Tension applied by the jack. Detailed Implementation

[0043] To clearly illustrate the technical features of the present invention, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0044] This embodiment describes a "self-propelled" forward movement control process for a two-column shield hydraulic support (model ZYA12000 / 24 / 50) applied to an overhead mining face with a coal seam dip angle β of 25°. The support base has a width W of 1.6 meters and a center distance D between the front and rear columns of 2.0 meters. Its control system incorporates pressure sensors, displacement sensors, and a dedicated programmable logic controller.

[0045] Follow these steps to perform the self-propelled forward movement of the hydraulic support:

[0046] S1: Setting the angle of the inclined reference plane;

[0047] In the initial stage of longwall mining, the surveyors accurately measured the current coal seam dip angle β = 25°. Using a proportionality coefficient m = 0.3 and the formula γ = m × β, the inclination reference plane angle γ = 0.3 × 25° = 7.5° was calculated. This angle serves as the macroscopic reference for mining the entire longwall face along the advancing direction, providing a fundamental reference for the attitude control of all supports.

[0048] S2: Pre-push to stabilize the base;

[0049] When the hydraulic support needs to move forward in the direction of the coal wall 4, the support controller first issues an instruction, and the multiple columns of the support are simultaneously lowered by a small amplitude, which lowers the column by 80mm to form a uniform and controllable gap of about 20mm between the support top beam 8 and the roof rock layer 7, effectively relieving part of the roof load.

[0050] Subsequently, the jack 3 of the operating support is used to apply a short-term, small pre-push or pre-pull force to the base 10 of the support, causing the front part of the base to move forward by 150mm, so as to eliminate the gap and loose material between the base 10 and the base plate 11, making the contact between the bottom surface of the entire base and the base plate more uniform and stable, and providing a solid mechanical basis for subsequent attitude adjustment.

[0051] S3: Differentiated column elongation and posture adjustment;

[0052] Multiple columns of the hydraulic support are operated asynchronously and differentially to achieve an elongation amount ΔL for column 1 closest to the coal face.m The elongation ΔL is greater than that of the support column 2 on the side closest to the goaf. c This causes the top beam 8 and base 10 of the support to change from their original posture to a preset tilted posture (preset elevation angle φ) with the front higher than the back. The dynamic calculation formula (ΔL) is used in this process. m – ΔL c The difference in expansion and contraction of the column is determined by the formula: ) = D × tan(β); ​​Taking D as 1.0 times the center distance, i.e., D = 2.0 m, substituting this into the formula, we get: (ΔL) m – ΔL c ) = 2.0m × tan(25°) ≈ 932mm.

[0053] The difference in initial elongation (ΔL) between the pillars near the coal face and the pillars near the goaf. m – ΔL c The width W of the bracket base and the support base satisfy the following relationship: 0.01W ≤ (ΔL) m – ΔL c The calculated value exceeds the range of 0.01W to 0.1W (i.e., 16mm to 160mm). To avoid structural risks caused by excessive attitude adjustment, the control system sets the target value of the actual extension difference to the upper limit of this range, i.e., 160mm, based on the above constraints.

[0054] During the process, the controller uses pressure sensors inside the column chambers on the support for feedback control. The controller sends a command to the electromagnetic proportional valve of the front column near the coal face, causing it to extend 160mm at a steady rate. Simultaneously, it sends a command to the rear column near the goaf, ensuring it remains basically stable or undergoes slight compensation during attitude adjustment. Through this asynchronous and differentiated operation, the support base generates a preset elevation angle φ. Based on the support geometry, φ≈arctan(0.160 / 1.6) ≈ 5.7°. This angle exceeds the preferred range of 1.0° to 4.0°, and the controller automatically limits it to 4.0° according to preset safety logic.

[0055] Once the support frame adopts an inclined posture with a "higher front and lower rear" orientation, the enormous vertical pressure F from the roof plate acts on the rear of the roof beam. Utilizing the roof pressure 12 from the roof rock strata 7 on the roof beam 8 as a load force, a stable instantaneous adhesive point (a physically stable area with extremely high contact pressure) is formed in the contact area between the rear of the support base 10 and the base plate 11. At this moment, the roof pressure 12 forms a long lever arm relative to this instantaneous adhesive point 5, creating a powerful clockwise forward tilting moment, providing the main driving force for self-propelled movement.

[0056] S4: Self-propelled and forward-moving execution;

[0057] Under the mechanical structure formed in step S3, the operating push jack 3 applies a pulling force pointing towards the coal wall; this pulling force forms a counterclockwise balancing torque relative to the instantaneous adhesive point 5 in S3. The main function of this pulling force is to overcome the friction between the base 10 and the bottom plate 11, and trigger a clockwise forward tilting torque driven by the top plate pressure 12. Once the torque balance is broken, the entire support will move forward in the expected rolling manner around the instantaneous adhesive point 5 along the slope of the working face until the support moves to the predetermined position. During the entire forward movement, the required pulling force is only about 40% of the rated pushing force, which is significantly less than the traditional pushing method.

[0058] S5: Reset and support restoration;

[0059] Once the support frame is in place, the controller instructs all columns to extend synchronously until they return to their original support state. The rear of the top beam then re-engages tightly with the top plate, returning to its original support state and reaching the rated initial support force (usually more than 80% of the working resistance), thus completing one full cycle of support frame forward movement.

[0060] In the above, the control of the differential expansion and contraction of the support column in step S3 is dynamically calculated based on the current actual coal seam dip angle of the overhead mining face, and the control formula is as follows:

[0061] (ΔL) m – ΔL c = D × tan(β) (2)

[0062] Among them, (ΔL) m – ΔL c ) represents the difference in column expansion and contraction, and D is 0.8 to 1.2 times the center distance between the columns near the coal face and the columns near the goaf.

[0063] Step S3 also includes a real-time dynamic correction process based on pressure feedback. This process is implemented using a closed-loop control algorithm based on angular step increments. The real-time dynamic correction process continues until the support completes the attitude tilting operation or enters the force self-propulsion stage. The closed-loop control algorithm is executed by a dedicated controller or programmable logic controller within the hydraulic support's control system. The controller receives pressure sensor signals and, according to the preset algorithm logic, sends control commands to the electromagnetic proportional valves of the corresponding columns to precisely adjust the column's elongation rate and final elongation.

[0064] The specific implementation is as follows:

[0065] A pressure sensor installed at the rear of the support beam monitors the pressure (P) of the top plate on the rear of the top beam in real time; when the pressure (P) exceeds the preset standard working pressure (P0), the preset elevation angle (φ) is automatically increased, and the preset elevation angle (φ) is determined by the following step adjustment formula (3):

[0066] φ = φ0 + (n-1) × Δφ (3)

[0067] Wherein, φ0 is the basic elevation angle, Δφ is the angular step increment value, and its value ranges from 0.1° to 0.5°; n represents the excess multiple of pressure P relative to P0, which is calculated by n = floor(P / P0), where floor indicates rounding down the result. The basic elevation angle φ0, standard working pressure P0, and angular step increment Δφ are all parameters that are pre-calibrated and stored in the support controller based on the support model, roof lithology grade, and working face mining experience.

[0068] During the execution of the real-time dynamic correction step, the controller also monitors the pressure changes in the column cavity. When it detects that the column pressure rises sharply due to the increase in elevation angle and approaches its safe working threshold, it issues a warning or automatically stops the current attitude adjustment to protect the safety of the hydraulic support structure.

[0069] Assume that during the attitude adjustment process in step S3, the working face experiences initial pressure from the top plate. During the attitude adjustment, the pressure sensor located at the rear of the support's top beam monitors the top plate pressure P in real time, which suddenly increases from the normal 42 MPa to 98 MPa. This signal is transmitted in real time to the support's PLC controller.

[0070] The calibration parameters are pre-stored in the controller: basic elevation angle φ0=2.0°, standard working pressure P0=45MPa, and angular step increment Δφ=0.3°.

[0071] The controller adopts a closed-loop control algorithm based on angular step increment. First, the overshoot multiple is calculated: n = floor(P / P0) = floor(98 / 45) = 2.

[0072] Then, using the step adjustment formula φ = φ0 + (n-1)×Δφ, the new target preset elevation angle is calculated: φ = 2.0° + (2-1) × 0.3° = 2.3°.

[0073] The controller then adjusts its control strategy, sending new commands to the electromagnetic proportional valve to fine-tune the extension of the front column, gradually increasing the support's elevation angle from the initial 4.0° (after limiting) to the target value of 2.3°. This automatic adjustment process allows the support to automatically adapt to the increased pressure from the roof, obtaining stronger self-propelled driving force and ensuring a smooth pushing process.

[0074] Meanwhile, the controller closely monitors pressure changes within all column cavities. When an increase in elevation angle causes the pressure in the front column to rise and approach its safe operating threshold, the controller immediately issues an audible and visual warning and automatically terminates the current attitude adjustment program to protect the hydraulic support structure from damage, demonstrating the high safety of this invention under extreme working conditions.

[0075] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A self-propelled forward movement control method for hydraulic supports based on the lever torque principle, characterized in that, Follow these steps to perform the self-propelled forward movement of the hydraulic support: S1: Setting the angle of the inclined reference plane; In the early stage of mining, the dip angle of the coal seam is measured, and the angle of the inclination reference surface of the working face is dynamically set based on the dip angle. The angle of the inclination reference surface satisfies the relationship (1) to ensure that a stable reference surface with an inclination angle of γ is formed along the advancing direction of the working face. γ = m × β (1) Where m is a proportionality coefficient ranging from 0.1 to 0.4; S2: Pre-push to stabilize the base; When the hydraulic support needs to move forward toward the coal wall (4), the support controller first issues an instruction to operate multiple columns of the support to simultaneously perform small-amplitude column lowering operations, so that a uniform and controllable gap is formed between the support top beam (8) and the roof rock layer (7); then, the support push jack (3) is operated to apply a short-term, small pre-push or pre-tension force to the support base (10); S3: Differentiated column elongation and posture adjustment; Multiple columns of the hydraulic support are operated asynchronously and differentially to elongate, resulting in an elongation ΔL of the column (1) closest to the coal face. m The elongation ΔL is greater than that of the support column (2) on the side closer to the goaf. c This causes the top beam (8) and base (10) of the support to change from their original posture to a preset tilted posture that is higher in the front and lower in the back; through this asynchronous and differentiated operation, the support base generates a preset elevation angle φ. When the support forms an inclined posture with the front higher than the back, the huge vertical pressure F of the top plate acts on the rear of the top beam. The pressure (12) of the top plate rock layer (7) on the top beam (8) is used as the load force. A stable instantaneous glue point (5) is formed in the contact area between the rear of the support base (10) and the bottom plate (11). At this time, the pressure (12) of the top plate forms a long lever arm relative to the instantaneous glue point (5), which creates a strong clockwise forward tilting moment and provides the main driving force for self-propelled movement. S4: Self-propelled and forward-moving execution; Under the mechanical structure formed in step S3, the operating push jack (3) applies a pulling force pointing towards the coal wall; this pulling force forms a counterclockwise balancing torque relative to the instantaneous adhesive point (5) in S3. The main function of this pulling force is to overcome the friction between the base (10) and the bottom plate (11) and trigger a clockwise forward tilting torque driven by the top plate pressure (12). The entire support then moves forward in the expected rolling manner around the instantaneous adhesive point (5) along the slope direction of the working face until the support moves to the predetermined position. S5: Reset and support restoration; Once the support frame is in place, the controller instructs all columns to extend synchronously until they return to their original support state. The rear of the top beam then re-engages tightly with the top plate, returning to its original support state and reaching the rated initial support force, thus completing one full cycle of support frame forward movement.

2. The self-propelled forward movement control method for a hydraulic support based on the lever torque principle according to claim 1, characterized in that, In step S3, the control of the differential expansion and contraction of the support pillars is dynamically calculated based on the current actual coal seam dip angle of the overhead mining face. The control formula is as follows: (ΔL m – ΔL c ) = D × tan(β) (2) Among them, (ΔL) m – ΔL c ) represents the difference in column expansion and contraction, and D is 0.8 to 1.2 times the center distance between the columns near the coal face and the columns near the goaf.

3. The self-propelled forward movement control method for hydraulic supports based on the lever torque principle according to claim 1, characterized in that, The difference in initial elongation between the column near the coal face and the column near the goaf and the width W of the support base satisfy the following relationship: 0.01W ≤ (ΔL) m – ΔL c ≤ 0.1W.

4. The self-propelled forward movement control method for hydraulic supports based on the lever torque principle according to claim 1, characterized in that, The preset elevation angle φ ranges from 1.0° to 4.0°.

5. The self-propelled forward movement control method for a hydraulic support based on the lever torque principle according to claim 1, characterized in that, The instantaneous adhesive point is not a physical structure, but refers to a contact area that is mechanically stable and serves as a torque fulcrum, where the rear of the base and the bottom plate generate a large contact pressure due to the pressure of the top plate after the bracket is adjusted.

6. The self-propelled forward movement control method for hydraulic supports based on the lever torque principle according to claim 1, characterized in that, In step S3, the control of the differential expansion and contraction of the support pillars is dynamically calculated based on the current actual coal seam dip angle of the overhead mining face. The control formula is as follows: (ΔL m – ΔL c ) = D × tan(β) (2) Among them, (ΔL) m – ΔL c ) represents the difference in column expansion and contraction, and D is 0.8 to 1.2 times the center distance between the columns near the coal face and the columns near the goaf.

7. The self-propelled forward movement control method for a hydraulic support based on the lever torque principle according to claim 1, characterized in that, Step S3 also includes a real-time dynamic correction process based on pressure feedback, which is implemented using a closed-loop control algorithm based on angular step increments, as follows: A pressure sensor installed at the rear of the support beam monitors the pressure (P) of the top plate on the rear of the top beam in real time; when the pressure (P) exceeds the preset standard working pressure (P0), the preset elevation angle (φ) is automatically increased, and the preset elevation angle (φ) is determined by the following step adjustment formula (3): φ = φ0 + (n-1) × Δφ (3) Wherein, φ0 is the basic elevation angle, Δφ is the angular step increment value, and its value ranges from 0.1° to 0.5°; n represents the excess multiple of pressure P relative to P0, which is calculated by n = floor(P / P0), where floor indicates rounding down the result. The basic elevation angle φ0, standard working pressure P0, and angular step increment Δφ are all parameters that are pre-calibrated and stored in the support controller based on the support model, roof lithology grade, and working face mining experience.

8. The self-propelled forward movement control method for a hydraulic support based on the lever torque principle according to claim 7, characterized in that, During the execution of the real-time dynamic correction step, the controller also monitors the pressure changes in the column cavity. When it detects that the column pressure rises sharply due to the increase in elevation angle and approaches its safe working threshold, it issues a warning or automatically stops the current attitude adjustment.

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