Rotary drilling rig self-adaptive speed regulation system based on pressure feedback

Abstract

The invention relates to the technical field of speed regulation of high-rotating-speed and high-power hydraulic couplers, and particularly discloses a rotary drilling rig self-adaptive speed regulation system based on pressure feedback, which comprises an acquisition module for calculating slip frequency and acquiring an actual torque value of a power head based on the slip frequency; the adjusting module is used for adjusting an engine throttle, so that the oil supply pressure is within a stable pressure range, and the rotating speed of a power head reaches a target rotating speed; the feedback module is used for controlling the slip frequency to return to a preset safety range when the pressure returns to the stable pressure range and the shell temperature of the hydraulic coupler is not higher than a preset value; and when the pressure returns to the stable pressure range and the shell of the hydraulic coupler exceeds the preset value, the slip frequency is kept within the preset slip frequency range. The drilling steady state and reliability are improved, and the energy consumption and the operation risk are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of high-speed and high-power hydraulic coupler speed regulation, and in particular to a rotary drilling rig adaptive speed regulation system based on pressure feedback. Background Art

[0002] A rotary drilling rig is a hole-forming equipment that integrates drilling, slag extraction, and wall protection. It drives the drill rod and drilling tools to rotate at high speed through the power head, transmitting the cutting force to the formation; at the same time, the negative pressure formed inside the drill rod or in the gap between the hole walls can lift the drill cuttings to the ground in time, achieving efficient slag removal.

[0003] Existing rotary drilling rigs often utilize closed-loop pressure control or constant speed control. However, these conditions often arise during drilling, including alternating soft and hard layers, hard rock impact, deephole oil line hysteresis, high temperature rise, and drill tool wear. When the load changes suddenly, relying solely on pressure thresholds or traditional PID control is unable to mitigate torque peaks within milliseconds, potentially leading to overshoot of the reducer ring gear, overflow shock from the valve block, and mast fatigue. During continuous deephole drilling, the hydraulic coupling heats up, causing the torque-slip curve to drift, distorting torque estimation, and causing steady-state speed drift. Summary of the Invention

[0004] The purpose of the present invention is to provide a rotary drilling rig adaptive speed regulation system based on pressure feedback to solve the above technical problems.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An adaptive speed control system for a rotary drilling rig based on pressure feedback. The acquisition module obtains the oil supply pressure P, engine speed n1, and power head speed n2 of the power head, calculates the difference Δn = n1 - n2 in real time, and calculates the ratio between the difference Δn and the engine speed as slip. Based on the slip, the actual torque value of the power head is obtained.

[0007] Regulation module: adjusts the engine throttle based on the actual torque value and fuel supply pressure, so that the fuel supply pressure is within the preset stable pressure range and the power head speed reaches the target speed. The target speed is determined based on the slip and the pressure difference. The pressure difference represents the difference between the fuel supply pressure P and the center value of the stable pressure range.

[0008] Feedback module: When the pressure returns to the stable pressure range and the shell temperature of the hydraulic coupling is not higher than the preset value, the original oil filling amount is gradually restored in a constant micro-oil replenishment manner until the slip returns to the preset safe range;

[0009] When the pressure returns to the stable pressure range and the shell of the fluid coupling exceeds the preset value, the slip is maintained within the preset slip range until the shell temperature of the fluid coupling is no higher than the preset value.

[0010] As a further solution of the present invention: when the instantaneous change rate of the oil supply pressure is greater than a preset impact threshold, the dedicated oil drain valve of the hydraulic coupling is opened to discharge a predetermined proportion of the working oil to increase the slip and weaken the torque peak transmitted to the power head.

[0011] As a further solution of the present invention, obtaining the actual torque value of the power head based on the slip includes:

[0012] Obtaining a pre-stored torque mapping curve, wherein the torque mapping curve is obtained from a bench calibration experiment and uses slip as an independent variable;

[0013] Substituting the slip into the torque mapping curve, the torque coefficient A is obtained. The torque coefficient A is multiplied by the nominal torque constant of the mechanical structure of the power head to obtain the actual torque value of the power head.

[0014] As a further solution of the present invention: determining the target speed includes:

[0015] Substituting the slip into a first curve to obtain a first coefficient, wherein the first reference curve has the slip as the abscissa and the speed correction coefficient as the ordinate;

[0016] Substituting the pressure difference into a second curve to obtain a second coefficient, wherein the second reference curve has the pressure difference as the horizontal coordinate and the speed correction coefficient as the vertical coordinate;

[0017] A preset arithmetic combination rule is executed to combine the first correction coefficient and the second correction coefficient into a comprehensive correction coefficient, and the comprehensive correction coefficient is multiplied by the nominal speed constant of the engine to obtain the target speed.

[0018] As a further solution of the present invention, obtaining the first curve includes:

[0019] The engine speed B when the engine is in no-load condition and the fuel supply pressure is at the center value of the stable pressure range is defined as the nominal speed constant;

[0020] When the engine maintains a nominal speed constant and the oil supply pressure is at the center of the stable pressure range, an external hydraulic brake is used to apply an external blocking force, gradually changing the power head speed and recording the slip in real time.

[0021] When the slip is a1 and the fuel supply pressure deviates from the center value of the stable pressure range, slowly reduce the engine throttle at a preset speed until the fuel supply pressure returns to the center value of the stable pressure range, and read the engine speed at this time;

[0022] The engine speed at this time is ratioed to the nominal speed constant to obtain a speed correction coefficient a2, and a first coordinate point (a1, a2) is generated. The first coordinate point is fitted to obtain a first curve.

[0023] As a further solution of the present invention, obtaining the second curve includes:

[0024] Restore the engine throttle to the nominal speed constant and keep the power head speed consistent with the engine speed;

[0025] Adjust the external blocking force to make the oil supply pressure higher or lower than the center value of the stable pressure range, record the pressure difference b1 and reduce or increase the engine throttle, and obtain the speed correction coefficient b2 to generate the second coordinate point (b1, b2). Fit the second coordinate point to obtain the second curve.

[0026] As a further solution of the present invention: the preset arithmetic combination rules include:

[0027] When the first coefficient and the second coefficient have the same positive and negative signs, the one with the larger absolute value between the two is used as the initial composite coefficient, and the one with the smaller absolute value between the two is used as the basis to perform offset correction on the initial composite coefficient according to a fixed ratio to obtain a comprehensive correction coefficient;

[0028] When the first coefficient and the second coefficient have different signs, the sign of the correction coefficient with the larger absolute value is used as the sign of the comprehensive correction coefficient, and the difference between the absolute values of the two is used as the absolute value of the comprehensive correction coefficient.

[0029] As a further solution of the present invention, adjusting the engine throttle based on the actual torque value and the fuel supply pressure includes:

[0030] mapping the pressure difference to a first throttle correction amount;

[0031] Calculate the difference between the target speed and the power head speed, record it as the speed deviation, and map the speed deviation to a second throttle correction amount;

[0032] Map the actual torque value to the torque proportional coefficient;

[0033] The first throttle correction amount is added to the second throttle correction amount to obtain a composite throttle correction amount, the torque proportional coefficient is multiplied by the composite throttle correction amount to obtain a comprehensive throttle correction amount, and the engine throttle is adjusted according to the comprehensive throttle correction amount.

[0034] The beneficial effects of the present invention are as follows:

[0035] 1) The present invention calculates slip in real time and maps the actual torque value of the power head. When a sudden increase in oil supply pressure is detected, the hydraulic coupling drain valve is driven to drain oil, actively increasing slip and synchronously coordinating throttle reduction. This discretizes and buffers torque impact, significantly reducing reducer ring gear overshoot, valve group overflow impact, and mast fatigue, significantly improving mechanical reliability and service life under hard rock sudden change conditions.

[0036] 2) A comprehensive correction algorithm based on dual slip-pressure reference curves enables real-time adaptation of engine speed and powerhead load under all operating conditions. The first curve characterizes the power coupling state based on slip, while the second curve reflects the hydraulic load based on pressure differential. The coefficients of the two curves are mathematically combined and synchronously applied to the target speed calculation. This algorithm can quickly maintain power balance, suppress idling and excessive speed reduction in the event of sudden load changes, and achieve dual closed-loop control of stable pressure and steady-state speed, improving drilling efficiency and reducing energy consumption and noise.

[0037] 3) Constant micro-oil replenishment and slip window adjustment are implemented based on the temperature rise of the hydraulic coupling to automatically compensate for temperature-induced torque-slip curve drift. The torque mapping curve is dynamically updated along with the safe slip zone, ensuring that torque estimation during long-duration deep-hole operations always remains close to the actual operating conditions, eliminating steady-state speed drift and load estimation distortion, ensuring stable operation in high-temperature environments, and delaying thermal degradation of hydraulic components and powertrain. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present invention will be further described below with reference to the accompanying drawings.

[0039] Figure 1 The present invention is a flow chart of a rotary drilling rig adaptive speed regulation system based on pressure feedback. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] See also Figure 1 As shown, the present invention is an adaptive speed regulation system for a rotary drilling rig based on pressure feedback, comprising:

[0042] Acquisition module: A piezoresistive pressure sensor is installed on the power head oil inlet pipe. The sensor core is in direct contact with the oil circuit and is isolated from high-frequency mechanical noise by a flexible vibration damping pad. The sensor converts instantaneous pressure into a digital signal and sends it to the main controller via the CAN bus. An electromagnetic speed pickup is placed on the outer side of the engine flywheel ring gear, generating a series of pulses per revolution. The main controller calculates the engine speed n1 based on the number of pulses per unit time and uses the flywheel's built-in positioning holes to complete the startup self-calibration zero position. A Hall effect encoder is installed at the output shaft end of the power head. The magnetic steel ring rotates at the same speed as the shaft. The encoder outputs a square wave signal, which is counted in real time by the main controller to obtain the power head speed n2. The software deburring algorithm is used to suppress rate burrs caused by rock crushing impact.

[0043] Calculate the difference Δn=n1-n2 in real time, and calculate the ratio between the difference Δn and the engine speed as the slip, and obtain the actual torque value of the power head based on the slip;

[0044] In a preferred embodiment, obtaining the actual torque value of the power head based on the slip includes:

[0045] On a laboratory bench, a power head was rigidly connected to an adjustable hydraulic brake and equipped with a high-precision tachometer and torque sensor. While maintaining the nominal engine speed, the brake back pressure was gradually increased from zero to raise the slip. Slip and output torque were simultaneously recorded to form raw scattered data. A piecewise polynomial torque mapping curve with slip as the independent variable was obtained through least squares fitting. The polynomial coefficients were written to the main controller's power-off non-amnestic Flash and archived along with the curve number and calibration date.

[0046] When the control system is running, the CPU first calls the corresponding polynomial coefficient from the Flash according to the curve number and loads it into the RAM. Then, the slip value calculated by the acquisition module is used in real time to call the cubic spline interpolation or directly substitute it into the piecewise polynomial to calculate the torque coefficient A. For example, when the slip is 0.06, the interpolation algorithm obtains A≈1.1. Then, the nominal torque constant pre-written into the EPROM along with the power head product model is read. This constant is derived from the maximum load value verified by static torque loading in the factory type test. Then, A is multiplied by this constant to obtain the actual torque value of the power head under the current working condition.

[0047] Regulation module: adjusts the engine throttle based on the actual torque value and fuel supply pressure, so that the fuel supply pressure is within the preset stable pressure range and the power head speed reaches the target speed. The target speed is determined based on the slip and the pressure difference. The pressure difference represents the difference between the fuel supply pressure P and the center value of the stable pressure range.

[0048] In a preferred embodiment of the present invention, determining the target speed includes:

[0049] Substituting the slip into a first curve to obtain a first coefficient, wherein the first reference curve has the slip as the abscissa and the speed correction coefficient as the ordinate;

[0050] Substituting the pressure difference into a second curve to obtain a second coefficient, wherein the second reference curve has the pressure difference as the horizontal coordinate and the speed correction coefficient as the vertical coordinate;

[0051] executing a preset arithmetic combination rule to combine the first correction coefficient and the second correction coefficient into a comprehensive correction coefficient, and multiplying the comprehensive correction coefficient by the nominal speed constant of the engine to obtain a target speed;

[0052] In a preferred embodiment of this embodiment, obtaining the first curve includes:

[0053] Disconnect the power head from the hydraulic system and return the oil. Set the minimum opening of the oil supply valve when the power head is idling so that the circuit neutral pressure is at the center value of the stable pressure range pre-calibrated by the proportional valve experiment. Then put the engine in idle gear and turn off all additional loads. Only the high-pressure oil pump is left to pump without any oil. At this time, the engine speed read by the crankshaft position encoder is B, which is written into the main controller EEPROM and used as the nominal speed constant.

[0054] The electronic throttle is locked to maintain duty cycle B, the oil supply pressure is fixed at the center value via the proportional relief valve, and the electromagnetic pressure regulating valve of the external hydraulic brake increases the back pressure in a step-by-step manner according to the test procedure. The brake back pressure is fed back in real time via the torque sensor of the torque rod. The result is superimposed on the output shaft of the power unit to form a load torque, thereby gradually reducing the power unit speed at several step points. The main controller calculates the slip every ten milliseconds using the flywheel speed pickup and the output shaft Hall encoder and stores it in the ring buffer.

[0055] When the average slip value in the buffer reaches a certain level a1 and the pressure sensor detects that the fuel supply pressure deviates from the center value by more than the set tolerance, the main controller starts to drive the electronic throttle according to the software timer, slowly reducing the throttle opening at a step rate not exceeding the set speed per second, while continuously monitoring the pressure curve. When the pressure value falls back into the center tolerance band, the current speed reading is immediately frozen and written to RAM;

[0056] The calculation core divides the frozen speed by the stored B to obtain the speed correction coefficient a2. The coordinate pair a1 and a2 is written to the Flash with a timestamp. After all the step points are collected, the built-in least squares algorithm performs piecewise cubic spline fitting on all the coordinate pairs. The coefficient matrix is refreshed into the data area of the control program, thereby generating a first reference curve with slip as the horizontal coordinate and the speed correction coefficient as the vertical coordinate, which is used for subsequent target speed calculation.

[0057] It should be noted that obtaining the second curve includes:

[0058] The electronic throttle duty cycle is restored to the nominal value stored in the EEPROM. The controller stabilizes the engine at a nominal speed constant B of approximately 1,800 rpm through a closed loop flywheel pickup. The proportional pressure reducing valve is then used to slowly release the back pressure of the external hydraulic brake to keep the difference between the speed measured by the power head Hall encoder and the engine speed within two rpm.

[0059] After the two are synchronized, the brake back pressure is adjusted in a step-by-step manner using the proportional relief valve as the actuator. Each step is maintained for five seconds, raising the oil supply pressure to 23 MPa and lowering it to 17 MPa within a tolerance band of plus or minus 0.3 MPa around the center value of the stable pressure range of 20 MPa. At this time, the pressure sensor has been calibrated at ten points and its accuracy is better than 0.25% of the full scale. The difference between its real-time reading and the center value is recorded as the pressure difference value b1;

[0060] The brake back pressure then locks, and the controller fine-tunes the electronic throttle at a rate of fifty revolutions per second. If b1 is positive, the throttle is increased; if b1 is negative, the throttle is decreased. Adjustment continues until the pressure reading falls back into the center tolerance band. The ratio of the engine speed read at this moment to the nominal speed constant B is used to obtain the speed correction factor b2. For example, when the pressure is three MPa above the center value, the throttle is increased by two percentage points, and the speed rises to 1,860 rpm, resulting in a b2 of approximately 1.03.

[0061] After each set of pressure difference and correction coefficient data is collected, the controller writes (b1, b2) to RAM and timestamps it. After all positive and negative deviation points are collected, the computational core uses the least squares cubic spline algorithm to fit all coordinate pairs. The resulting coefficient matrix is encrypted and written to Flash, forming a second reference curve with pressure difference as the horizontal coordinate and speed correction coefficient as the vertical coordinate. This curve is then used by the target speed calculation module in subsequent online control.

[0062] It should be noted that the preset arithmetic combination rules include:

[0063] The controller first reads the first coefficient k1 and the second coefficient k2 from the first reference curve and the second reference curve in real time and stores them in RAM. It then performs a logical exclusive OR operation on the two coefficients to confirm whether they are the same or different. If they are the same, it calls the absolute value comparison instruction to take the larger one as the initial synthesis coefficient k.

[0064] The smaller absolute value is multiplied by the preset proportionality factor λ to obtain the offset Δk. λ is set to a constant between 0.25 and 0.35 during bench calibration based on the system's sensitivity to oscillation. Then, k is offset by Δk in the sign direction to obtain the comprehensive correction coefficient k. For example, if k1 is 1.1 and K2 is 0.7, and both are positive, k is 1.1. Δk is equal to 0.7 multiplied by λ, which is approximately 0.2, so k is approximately 1.3.

[0065] If the two coefficients have different signs, the sign of the larger one is directly assigned to the comprehensive correction coefficient after the absolute value comparison, and the difference between the absolute values of the two coefficients is used as the amplitude of the comprehensive correction coefficient. For example, when k1 is negative 0.9 and k2 is positive 1.2, the comprehensive correction coefficient takes a positive sign because the absolute value of 1.2 is larger. The amplitude is 1.2 minus 0.9 equals 0.3, so k is positive 0.3. All calculation results are written to the register after CRC verification for reading by the target speed module. At the same time, k is added to the ring buffer together with the current slip and pressure difference for future curve recalibration.

[0066] In another preferred embodiment of the present invention, adjusting the engine throttle based on the actual torque value and the fuel supply pressure includes:

[0067] The main controller subtracts the pressure sensor output from the 20 MPa center pressure to obtain the pressure difference and calls a one-dimensional table lookup function to find the corresponding throttle gain coefficient table in Flash. This table is derived from the bench pressure step test and uses the pressure difference as the index and the step distance of 0.1 MPa to output the first throttle correction value g1 using linear interpolation;

[0068] Calculate the speed deviation and interpolate it into another PI gain curve table with the speed deviation as the index to obtain the second throttle correction value g2;

[0069] Synchronously calculate the actual torque T obtained by the piecewise polynomial a Enter the torque proportional function, which divides the output coefficient β into eleven levels in the range of zero to rated torque and ranges from 0.8 to 1.2 and is smoothed with cubic spline. If T a If it accounts for 70% of the rated torque, β is about 0.95;

[0070] Add g1 and g2 to get the synthetic throttle correction g and multiply it by β to get the comprehensive throttle correction G. Then check the sign and amplitude of G. If it exceeds the protection threshold of plus or minus 10%, it will be saturated and limited. Finally, write G into the PWM register to change the duty cycle of the electronic throttle stepper motor to achieve the engine throttle increment or decrement.

[0071] The first pressure difference-throttle gain table was established through a bench pressure step test: after locking the engine at the nominal speed constant B and stabilizing the fuel supply pressure at a central value of 20 MPa, a proportional valve was used to quickly apply positive and negative step back pressures. Each step amplitude was 0.1 MPa and covered the range from negative 3 MPa to positive 3 MPa. The pressure sensor and injection pump actuator started sampling from a synchronous trigger signal at a sampling frequency of 2 kHz, recording the engine electronic throttle duty cycle, fuel supply pressure, and instantaneous power head speed. Subsequently, in the data processing software, the pressure difference ΔP 30 milliseconds after the step occurred was used as the horizontal axis, and the throttle duty cycle increment ΔG required for the engine to reach a quasi-steady state was used as the vertical axis. Records containing abnormal oscillations were eliminated, and the remaining points were smoothed with cubic spline. This generated a pressure difference-throttle correction table with an index step of 0.1 MPa and wrote it to Flash.

[0072] The second speed deviation-PI gain curve chart is obtained through closed-loop speed regulation testing: the external brake is closed to maintain the pressure at the center value. The controller superimposes a sinusoidal disturbance with an amplitude of no more than ±5% on the electronic throttle near the nominal duty cycle, introducing a speed deviation of less than 40 revolutions per minute and recording the speed deviation Δn and the steady-state throttle change ΔG after vector control in real time. The average gain of ΔG to Δn is calculated every ten revolutions. The proportional and integral coefficients are preliminarily estimated using the Ziegler-Nichols law, and then fine-tuned on the test bench to ensure that the overshoot and settlement time of the system step response fall within the design window. Finally, the discrete gain points are compiled into a lookup table algorithm using piecewise linear interpolation. After passing the CRC check, it is written to Flash. This forms a speed deviation-throttle correction table for rapid online control.

[0073] In another preferred embodiment of the present invention, the piezoresistive pressure sensor installed in the oil inlet branch of the power head is read at a frequency of 1,000 Hz. The difference between two adjacent sampling points is calculated and divided by the sampling period to obtain an instantaneous rate of change. When the result exceeds an impact threshold calculated based on the drilling depth, for example, initially set at approximately 0.5 MPa per millisecond and decreasing by 10% with every ten-meter increase in depth, the controller energizes the output port of the MOS valve driven by the optical isolation to open the dedicated oil discharge solenoid valve of the hydraulic coupler. The internal microprocessor simultaneously calculates the target discharge volume by multiplying the total oil volume of the coupler by a calibration ratio of 5% and converts it into an opening time. The valve energization time obtained based on a measured flow rate of 20 milliliters per second is generally between 200 and 400 milliseconds.

[0074] During the oil discharge process, the main controller continuously recalculates the slip in a ten-millisecond cycle. If the slip increase reaches the expected value and the pressure rise rate has dropped below the threshold, the valve will be closed in advance. If the slip is still insufficient after the oil discharge is completed or the pressure derivative rebounds, the secondary oil discharge logic will be entered. However, the total discharge volume is limited to within 8% to prevent excessive oil loss in the coupler.

[0075] After the valve is closed, the hysteresis relay driven by high-frequency pulses keeps the valve core self-locked to prevent repeated action. At the same time, the number of oil discharges and the discharge volume are written into the power-off holding area for the temperature rise oil replenishment algorithm to call. This increases the slip within a few hundred milliseconds after the load impact occurs, weakens the torque peak, and isolates the mechanical impact in the liquid shear inside the coupler.

[0076] In another preferred embodiment of the present invention, the real-time setting of the impact threshold is completed by a "depth-threshold mapping function" in the controller. This function is obtained during the experimental calibration phase by comparing the oil supply pressure rising rate and the torque peak arrival time of the power head at different drilling depths. The function is in the form of a linear decreasing curve with a lower limit added.

[0077] For example, in the factory bench and on-site shallow hole verification, the threshold value when the depth is 0m is recorded as X≈1.0MPas -1 This value corresponds to the case of the shortest oil path and the smallest elasticity. When measuring a 60m deep hole, the threshold is reduced to X1≈0.25MPas after considering the increase in response hysteresis measured by the tubing volume expansion and the hydraulic wave velocity. -1 ;

[0078] Substitute the real-time drilling depth d output by the depth sensor into the linear function of ΔP(d) = Xk×d (k≈0.012MPas -1 m -1 (derived from the average regression of multiple wells), if the calculated value is lower than the safety lower limit Xmin≈0.20MPas -1 Then take the lower limit to avoid false triggering;

[0079] In order to avoid excessive oil drainage in deep hole situations and cause a sudden drop in torque, the depth-related minimum torque Tmin(d) = T0 + α × d (T0 is the nominal starting torque, α≈50N·mm -1 From the rock sample drilling resistance test), only when the instantaneous pressure change rate is greater than ΔP(d) and the current torque T a The oil drain valve will be opened only when ≥Tmin(d);

[0080] After the valve is closed, it can be re-triggered only when ΔP falls back to (ΔP(d)-ε), where ε≈0.05MPas -1 Determined by step test to form a hysteresis band to prevent high frequency switching;

[0081] The above dual-condition logic is executed in real time according to the depth during the entire operation process, thereby ensuring timely peak reduction in the shallow hole stage and preventing continuous oil discharge and insufficient torque due to low thresholds in the deep hole stage.

[0082] Feedback module: When the pressure sensor detects that the oil supply pressure is stable within the range of 20 MPa plus or minus 0.3 MPa for one second and the actual temperature measured by the thermocouple of the hydraulic coupling housing is no higher than 85 degrees Celsius, the main controller enters the oil replenishment mode and uses a pulsed micro-oil replenishment pump to fill the coupler with working oil at a fixed rate of approximately 0.5 ml each time. The pulse interval is set to five seconds to allow the oil to fully disperse and absorb heat and allow the slip measurement value to converge again;

[0083] During the oil filling process, the controller recalculates the slip every 50 milliseconds. When the slip drops back to the safe range of 0.02 to 0.04, the oil filling is stopped and the current oil filling amount is written into the power-off retention area to ensure the consistency of the benchmark for subsequent oil draining and filling algorithms.

[0084] If the pressure has been restored but the shell temperature is still higher than 85 degrees Celsius, the controller will keep the oil replenishment pump closed and expand the slip control window to three times the safety range, that is, between 0.06 and 0.12. At this time, by maintaining the oil drain valve in a slightly open gap state, some oil continues to circulate externally to dissipate heat, and checks the temperature curve at a cycle of 500 milliseconds. Only when the temperature is lower than the threshold for five consecutive seconds will the oil drain valve be closed and the aforementioned micro-oil replenishment process be started to gradually restore the original oil filling amount while pulling the slip back to the safe zone.

[0085] The above formulas are all dimensionless and numerical calculations. The formulas are obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters and thresholds in the formulas are set by technicians in this field according to actual conditions.

[0086] The above is a detailed description of an embodiment of the present invention. However, the content is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A rotary drilling rig adaptive speed control system based on pressure feedback, characterized in that: include: Acquisition module: obtains the oil supply pressure P of the power head, the engine speed n1 and the power head speed n2, calculates the difference Δn = n1-n2 in real time, and calculates the ratio between the difference Δn and the engine speed as the slip, and obtains the actual torque value of the power head based on the slip; Regulation module: adjusts the engine throttle based on the actual torque value and fuel supply pressure, so that the fuel supply pressure is within the preset stable pressure range and the power head speed reaches the target speed. The target speed is determined based on the slip and the pressure difference. The pressure difference represents the difference between the fuel supply pressure P and the center value of the stable pressure range. Feedback module: When the pressure returns to the stable pressure range and the shell temperature of the hydraulic coupling is not higher than the preset value, the original oil filling amount is gradually restored in a constant micro-oil replenishment manner until the slip returns to the preset safe range; When the pressure returns to the stable pressure range and the shell of the fluid coupling exceeds the preset value, the slip is maintained within the preset slip range until the shell temperature of the fluid coupling is no higher than the preset value.

2. The rotary drilling rig adaptive speed control system based on pressure feedback according to claim 1, characterized in that: When the instantaneous rate of change of the oil supply pressure is greater than the preset impact threshold, the dedicated oil drain valve of the hydraulic coupling is opened to discharge a predetermined proportion of working oil to increase the slip and weaken the torque peak transmitted to the power head.

3. The rotary drilling rig adaptive speed control system based on pressure feedback according to claim 1, characterized in that: The actual torque value of the power head based on slip is obtained by: Obtaining a pre-stored torque mapping curve, wherein the torque mapping curve is obtained from a bench calibration experiment and uses slip as an independent variable; Substituting the slip into the torque mapping curve, the torque coefficient A is obtained. The torque coefficient A is multiplied by the nominal torque constant of the mechanical structure of the power head to obtain the actual torque value of the power head.

4. The rotary drilling rig adaptive speed control system based on pressure feedback according to claim 1, characterized in that: Determining the target speed includes: Substituting the slip into a first curve to obtain a first coefficient, wherein the first reference curve has the slip as the abscissa and the speed correction coefficient as the ordinate; Substituting the pressure difference into a second curve to obtain a second coefficient, wherein the second reference curve has the pressure difference as the horizontal coordinate and the speed correction coefficient as the vertical coordinate; A preset arithmetic combination rule is executed to combine the first correction coefficient and the second correction coefficient into a comprehensive correction coefficient, and the comprehensive correction coefficient is multiplied by the nominal speed constant of the engine to obtain the target speed.

5. The rotary drilling rig adaptive speed control system based on pressure feedback according to claim 4, characterized in that: Obtaining the first curve includes: The engine speed B when the engine is in no-load condition and the fuel supply pressure is at the center value of the stable pressure range is defined as the nominal speed constant; When the engine maintains a nominal speed constant and the oil supply pressure is at the center of the stable pressure range, an external hydraulic brake is used to apply an external blocking force, gradually changing the power head speed and recording the slip in real time. When the slip is a1 and the fuel supply pressure deviates from the center value of the stable pressure range, slowly reduce the engine throttle at a preset speed until the fuel supply pressure returns to the center value of the stable pressure range, and read the engine speed at this time; The engine speed at this time is ratioed to the nominal speed constant to obtain a speed correction coefficient a2, and a first coordinate point (a1, a2) is generated. The first coordinate point is fitted to obtain a first curve.

6. The rotary drilling rig adaptive speed control system based on pressure feedback according to claim 5, characterized in that: Obtaining the second curve includes: Restore the engine throttle to the nominal speed constant and keep the power head speed consistent with the engine speed; Adjust the external blocking force to make the oil supply pressure higher or lower than the center value of the stable pressure range, record the pressure difference b1 and reduce or increase the engine throttle, and obtain the speed correction coefficient b2 to generate the second coordinate point (b1, b2). Fit the second coordinate point to obtain the second curve.

7. The rotary drilling rig adaptive speed control system based on pressure feedback according to claim 6, characterized in that: The preset arithmetic combination rules include: When the first coefficient and the second coefficient have the same positive and negative signs, the one with the larger absolute value between the two is used as the initial composite coefficient, and the one with the smaller absolute value between the two is used as the basis to perform offset correction on the initial composite coefficient according to a fixed ratio to obtain a comprehensive correction coefficient; When the first coefficient and the second coefficient have different signs, the sign of the correction coefficient with the larger absolute value is used as the sign of the comprehensive correction coefficient, and the difference between the absolute values of the two is used as the absolute value of the comprehensive correction coefficient.

8. The rotary drilling rig adaptive speed control system based on pressure feedback according to claim 1, characterized in that: Adjusting the engine throttle based on the actual torque value and fuel supply pressure includes: mapping the pressure difference to a first throttle correction amount; Calculate the difference between the target speed and the power head speed, record it as the speed deviation, and map the speed deviation to a second throttle correction amount; Map the actual torque value to the torque proportional coefficient; The first throttle correction amount is added to the second throttle correction amount to obtain a composite throttle correction amount, the torque proportional coefficient is multiplied by the composite throttle correction amount to obtain a comprehensive throttle correction amount, and the engine throttle is adjusted according to the comprehensive throttle correction amount.

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