A rotary drilling rig adaptive speed regulation system based on pressure feedback

Abstract

The present application relates to high-speed and high-power hydraulic coupler speed regulation technical field, specifically disclose a kind of self-adapting speed regulation system of rotary drilling rig based on pressure feedback, comprising: acquisition module: calculate slip, based on the actual torque value of power head that slip obtains;Adjustment module: adjust engine throttle, so that the oil supply pressure is in stable pressure range, and the speed of power head reaches target speed;Feedback module: when pressure returns to stable pressure range and the temperature of the shell of hydraulic coupler is not higher than preset value, control slip to return to preset safety range;When pressure returns to stable pressure range and the shell of hydraulic coupler exceeds preset value, keep slip in preset slip range.The present application improves drilling steady state and reliability, and reduces energy consumption and operating risk.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high-speed and high-power hydraulic coupler speed regulation, and particularly relates to a rotary drilling rig adaptive speed regulation system based on pressure feedback. BACKGROUND

[0002] The rotary drilling rig is a hole-forming device integrating drilling, slag extraction and wall protection, which rotates the drill rod and drill tool at high speed through the power head to transmit the cutting force to the stratum; at the same time, the negative pressure formed in the drill rod or the hole wall gap can timely lift the drilling slag to the ground to realize efficient slag removal.

[0003] The existing rotary drilling rig is mostly controlled by pressure closed loop or constant speed, but in the drilling process, the alternating soft and hard layers, hard rock impact, deep hole oil lag, high temperature rise and drill tool wear and other working conditions are often encountered. When the load suddenly changes, only the pressure threshold or the traditional PID cannot weaken the torque peak value in milliseconds, which easily causes the over-shooting of the reducer gear ring, the overflow impact of the valve group and the fatigue of the mast; when the continuous deep hole operation is performed, the temperature rise of the hydraulic coupler causes the torque-slip curve to drift, the torque estimation to be distorted and the steady-state rotating speed to drift. SUMMARY

[0004] The application aims to provide a rotary drilling rig adaptive speed regulation system based on pressure feedback to solve the above technical problems.

[0005] The application can be realized by the following technical scheme.

[0006] The rotary drilling rig adaptive speed regulation system based on pressure feedback comprises a collection module, an adjustment module and a feedback module.

[0007] The collection module acquires the oil supply pressure P of the power head, the engine rotating speed n1 and the power head rotating speed n2, calculates the difference value Δn = n1-n2 in real time, and calculates the ratio between the difference value Δn and the engine rotating speed as the slip, and acquires the actual torque value of the power head based on the slip.

[0008] The adjustment module adjusts the engine throttle based on the actual torque value and the oil supply pressure, so that the oil supply pressure is in the preset stable pressure range, and the power head rotating speed reaches the target rotating speed, the target rotating speed is determined based on the slip and the pressure difference value, and the pressure difference value represents the difference between the oil supply pressure P and the center value of the stable pressure range.

[0009] When the pressure returns to the stable pressure range and the shell temperature of the hydraulic coupler is not higher than the preset value, the original oil charge is gradually restored in the constant trace oil supplementing mode until the slip returns to the preset safety range.

[0010] As a further aspect of the present invention: 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, so as to increase the slip and weaken the peak torque transmitted to the power head.

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

[0012] Obtain a pre-stored torque mapping curve, which is obtained from a bench calibration experiment with slip as the independent variable;

[0013] Substituting the slip into the torque mapping curve, we obtain the torque coefficient A. Multiplying the torque coefficient A by the nominal torque constant of the power head mechanical structure, we obtain the actual torque value of the power head.

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

[0015] Substituting the slip into the first curve yields the first coefficient, with the slip as the horizontal axis and the speed correction coefficient as the vertical axis of the first reference curve.

[0016] Substitute the pressure difference value into the second curve to obtain the second coefficient. The second reference curve has the pressure difference value on the horizontal axis and the speed correction coefficient on the vertical axis.

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

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

[0019] The engine speed B is defined as the nominal speed constant when the engine is under no-load conditions and the fuel supply pressure is at the center of the stable pressure range.

[0020] With the engine maintaining its nominal speed constant and the oil supply pressure at the center of the stable pressure range, an external resistance force is applied by an external hydraulic brake to gradually change the speed of the power head and record the slip in real time.

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

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

[0023] As a further aspect 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 resistance to make the fuel supply pressure higher or lower than the center value of the stable pressure range, record the pressure difference b1, decrease 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 aspect of the present invention: the preset arithmetic combination rules include:

[0027] When the first coefficient and the second coefficient have the same sign, the one with the larger absolute value is taken as the initial composite coefficient, and the one with the smaller absolute value is taken as the benchmark to offset and correct the initial composite coefficient according to a fixed ratio to obtain the comprehensive correction coefficient.

[0028] When the signs of the first coefficient and the second coefficient are different, 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 aspect of the present invention: adjusting the engine throttle based on the actual torque value and fuel supply pressure includes:

[0030] Map the pressure difference to the first throttle correction value;

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

[0032] Map the actual torque value to a torque proportionality coefficient;

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

[0034] The beneficial effects of this invention compared to the prior art are as follows:

[0035] 1) This invention calculates the slip difference in real time and maps it to the actual torque value of the power head; when a sudden surge in the oil supply pressure is detected, the hydraulic coupling drain valve is driven to release oil, actively increasing the slip difference and simultaneously coordinating the throttle to decrease, thus discretizing and buffering the torque impact, significantly reducing the overshoot of the reducer gear ring, the overflow impact of the valve group and the fatigue of the mast, and significantly improving the mechanical reliability and service life under sudden hard rock working conditions.

[0036] 2) A comprehensive correction algorithm based on slip-pressure dual reference curves enables real-time adaptive control of engine speed and power head load under all operating conditions. The first curve represents the power coupling state based on slip, and the second curve reflects the hydraulic load based on pressure difference. The coefficients of the two curves are arithmetically combined and applied synchronously to the target speed calculation. This enables rapid maintenance of power balance, suppression of idling and excessive speed reduction during sudden load changes, and realization of dual closed-loop control of stable pressure and steady-state speed, thereby improving drilling efficiency and reducing energy consumption and noise.

[0037] 3) Based on the temperature rise of the hydraulic coupler, constant micro-oil replenishment and slip window adjustment are implemented to automatically compensate for the torque-slip curve drift caused by temperature; the torque mapping curve is dynamically updated with the safe slip zone, so that the torque estimation during long-term deep hole operation is always close to the actual working conditions, eliminating steady-state speed drift and load estimation distortion, ensuring stable operation in high-temperature environment, and delaying the thermal decay of hydraulic components and powertrain. Attached Figure Description

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

[0039] Figure 1 This is a schematic diagram of the adaptive speed control system for rotary drilling rigs based on pressure feedback according to the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see Figure 1 As shown, the present invention is an adaptive speed control system for rotary drilling rigs based on pressure feedback, comprising:

[0042] The data acquisition module includes a piezoresistive pressure sensor installed on the oil inlet pipe of the power head. The sensor core is in direct contact with the oil circuit, and high-frequency mechanical noise is isolated by a flexible damping pad. The sensor converts the instantaneous pressure into a digital signal and sends it to the main controller via the CAN bus. An electromagnetic speed sensor is arranged on the outside of the flywheel ring gear of the engine, 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 positioning hole on the flywheel to complete the self-calibration of the zero position upon startup. A Hall effect encoder is set 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 encoder also uses a software deburring algorithm to suppress the rate burrs caused by rock fragmentation impact.

[0043] The difference Δn = n1 - n2 is calculated in real time, and the ratio between the difference Δn and the engine speed is calculated as the slip. The actual torque value of the power head is obtained based on the slip.

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

[0045] On a laboratory bench, the power head is rigidly connected to an adjustable hydraulic brake and equipped with a high-precision tachometer and torque sensor. Under the condition that the engine maintains the nominal speed constant, the back pressure of the brake is gradually increased to make the slip increase from zero. At the same time, the slip and output torque are recorded to form raw scattered data. The piecewise polynomial torque mapping curve with slip as the independent variable is obtained by fitting with the least squares method. The polynomial coefficients are written into the power-off non-memory Flash of the main controller and archived together with the curve number and calibration date.

[0046] When the control system is running, the CPU first retrieves the corresponding polynomial coefficients from Flash according to the curve number and loads them into RAM. Then, it uses the slip value calculated by the acquisition module in real time to call 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, A≈1.1 is obtained according to the interpolation algorithm. Then, the nominal torque constant pre-written into the EPROM with the power head product model is read. This constant comes from the maximum load value verified by static torque loading in the factory type test. A is then multiplied by this constant to obtain the actual torque value of the power head under the current working condition.

[0047] Adjustment module: Adjusts engine throttle based on actual torque value and fuel supply pressure to keep fuel supply pressure within a preset stable pressure range and ensure that the power head speed reaches the target speed. The target speed is determined based on slip and pressure difference. The pressure difference represents the difference between 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 rotational speed includes:

[0049] Substituting the slip into the first curve yields the first coefficient, with the slip as the horizontal axis and the speed correction coefficient as the vertical axis of the first reference curve.

[0050] Substitute the pressure difference value into the second curve to obtain the second coefficient. The second reference curve has the pressure difference value on the horizontal axis and the speed correction coefficient on the vertical axis.

[0051] The preset arithmetic combination rules are executed to combine the first correction coefficient and the second correction coefficient into a comprehensive correction coefficient. The comprehensive correction coefficient is then multiplied by the nominal speed constant of the engine to obtain the target speed.

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

[0053] Disconnect the return oil from the power head and the hydraulic system, set the oil supply valve to the minimum opening when the power head is idling, so that the circuit mid-pressure is at the center value of the stable pressure range calibrated by the proportional valve test in advance, then put the engine in idle gear and turn off all additional loads, leaving only the high-pressure oil pump to idle. 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 the duty cycle of B. The oil supply pressure is fixed at the center value through the proportional relief valve, and the electromagnetic pressure regulating valve of the external hydraulic brake increases the back pressure in a step manner according to the test procedure. The back pressure of the brake is fed back in real time through the torque sensor of the torque rod. The result is superimposed on the output shaft of the power head to form the load torque, so that the speed of the power head gradually decreases at several step points. Every ten milliseconds, the main controller uses the flywheel speed pickup and the output shaft Hall encoder to calculate the slip and store it in the annular buffer.

[0055] When the average slip in the buffer reaches a certain level a1 and the pressure sensor detects that the oil 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, and slowly reduces the throttle opening by a step of no more than the set speed per second. During this period, the pressure curve is continuously monitored until the pressure value falls back into the center tolerance zone, at which point the current speed reading is frozen and written to RAM.

[0056] The processing core divides the frozen speed with the stored B to obtain the speed correction coefficient a2. The coordinate pair a1 and a2 are written to Flash with a timestamp. After all step points are collected, the built-in least squares algorithm performs piecewise cubic spline fitting on all coordinate pairs. The coefficient matrix is ​​refreshed into the data area of ​​the control program, thereby generating the first reference curve with slip as the horizontal axis and speed correction coefficient as the vertical axis, 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 the nominal speed constant B of about 1,800 revolutions per minute through the flywheel speed sensor closed loop. The back pressure of the external hydraulic brake is slowly released by the proportional pressure reducing valve, so that the difference between the actual speed measured by the power head Hall encoder and the engine speed is kept within two revolutions per minute.

[0059] After the two are synchronized, the proportional relief valve is used as the actuator to adjust the brake back pressure in a stepwise manner. Each step is held for five seconds. The oil supply pressure is raised to 23 MPa and lowered to 17 MPa respectively within the tolerance range of ±0.3 MPa around the center value of 20 MPa of the stable pressure range. At this time, the pressure sensor is calibrated at 10 points and the 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] Subsequently, the back pressure of the locking brake no longer changes, 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. The adjustment continues until the pressure reading falls back to the center tolerance zone. At this moment, the ratio of the engine speed read to the nominal speed constant B is used to obtain the speed correction coefficient b2. For example, when the pressure is three MPa higher than the center value, the throttle is increased by two percentage points, and the speed rises to 1,860 revolutions per second, thus obtaining b2 approximately equal to 1.03.

[0061] After each set of pressure difference and correction coefficient data is collected, the controller writes (b1, b2) into RAM and timestamps it. After all positive and negative deviation points are collected, the computing core calls the least square cubic spline algorithm to fit all coordinate pairs. The generated coefficient matrix is ​​encrypted and written into Flash, thus forming a second reference curve with pressure difference as the horizontal axis and speed correction coefficient as the vertical axis, which is 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 performs a logical XOR operation on the two 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 a preset proportional coefficient λ as the offset Δk. λ is set to a constant in the range of 0.25 to 0.35 in bench calibration based on the system's sensitivity to oscillation. Then, k is offset by Δk according to the sign direction to obtain the comprehensive correction coefficient k. For example, when k1 is 1.1, K2 is 0.7 and both are positive, k is 1.1, and Δk is equal to 0.7 multiplied by λ, which is approximately 0.2. Therefore, k is about 1.3.

[0065] If the two coefficients have different signs, the larger sign is directly assigned to the comprehensive correction coefficient after comparing their absolute values. The difference between the absolute values ​​of the two coefficients is then used as the magnitude of the comprehensive correction coefficient. For example, if k1 is -0.9 and k2 is +1.2, the comprehensive correction coefficient is positive because the absolute value of 1.2 is larger, and the magnitude is 1.2 minus 0.9, which equals 0.3. Therefore, k is +0.3. All calculation results are written to the register after CRC verification for the target speed module to read. At the same time, k, along with the slip and pressure difference of the current calculation, is added to the annular buffer for future curve recalibration.

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

[0067] The main controller subtracts the pressure sensor output from the 20 MPa center pressure to obtain the pressure difference value and calls a one-dimensional lookup table 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, with a step of 1 MPa and linear interpolation to output the first throttle correction amount g1.

[0068] The speed deviation is calculated and interpolated in another PI gain piecewise linear table indexed by the speed deviation to obtain the second throttle correction amount g2;

[0069] The actual torque T obtained by the piecewise polynomial is simultaneously calculated. a The torque proportional function is input, which divides the range from zero to rated torque into eleven output coefficients β ranging from 0.8 to 1.2 and is smoothed with cubic splines. If T a If the rated torque accounts for 70%, then β is approximately 0.95.

[0070] Add g1 and g2 to get the synthetic throttle correction amount g, and multiply it by β to get the comprehensive throttle correction amount G. Then check the sign and amplitude of G. If it exceeds the protection threshold of ±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 realize the increment or decrement of the engine throttle.

[0071] The first pressure difference-throttle gain table was established through bench pressure step tests: After locking the engine at the nominal speed constant B and stabilizing the fuel supply pressure at the center value of 20 MPa, positive and negative step back pressures were quickly given by a proportional valve. Each step amplitude was 0.1 MPa and covered the range from -3 MPa to +3 MPa. The pressure sensor and fuel injection pump actuator were sampled starting from the synchronous trigger signal at a sampling frequency of 2 kHz, recording the engine electronic throttle duty cycle, fuel supply pressure, and instantaneous speed of the power head. Subsequently, in the data processing software, the pressure difference ΔP at 30 milliseconds after the step occurred was used as the abscissa, and the throttle duty cycle increment ΔG required for the engine to reach quasi-steady state was used as the ordinate. Records containing abnormal oscillations were removed, and the remaining points were smoothed by cubic splines. 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 piecewise linear table was obtained through closed-loop speed control test: the external brake was closed and the pressure was kept at the center value. The controller superimposed a sinusoidal disturbance with an amplitude not exceeding ±5% on the electronic throttle near the nominal duty cycle, introducing a speed deviation within 40 revolutions per minute and recording the speed deviation Δn and the steady-state throttle change ΔG after vector adjustment in real time. The average gain of ΔG to Δn was calculated in groups of 10 revolutions. The proportional and integral coefficients were initially estimated using the Ziegler-Nichols rule and then fine-tuned cyclically on the test bench to make the overshoot and settling time of the system step response fall within the design window. Finally, the discrete gain points were compiled into a lookup table algorithm using piecewise linear interpolation and written into Flash after CRC verification, thus forming a speed deviation-throttle correction table for quick online control.

[0073] In another preferred embodiment of the present invention, the value of the piezoresistive pressure sensor installed in the oil inlet branch of the power head is read at a frequency of 1 kHz. The difference between two adjacent sampling points is divided by the sampling period to obtain the instantaneous rate of change. When the result exceeds the impact threshold calculated based on the drilling depth, for example, initially set to about 0.5 MPa per millisecond and decreasing by 10% for every 10 meters of depth increase, the controller opens the dedicated oil discharge solenoid valve of the hydraulic coupler by energizing the output port of the optically isolated MOS valve. At the same time, the internal microprocessor calculates the target discharge volume according to the total oil filling volume of the coupler multiplied by 5% of the calibration ratio and converts it into the opening time. The valve energizing time obtained based on the measured flow rate of 20 ml per second is usually between 200 and 400 milliseconds.

[0074] During the oil discharge process, the main controller continuously recalculates the slip difference at a 10-millisecond cycle. If the slip difference increases to the expected increase and the pressure rise rate has dropped below the threshold, the valve will be closed in advance. If the slip difference is still insufficient or the pressure derivative rebounds after the oil discharge is completed, the secondary oil discharge logic will be entered, but the total discharge volume will be limited to within 8% to prevent the coupler from losing too much oil.

[0075] After the valve is closed, the high-frequency pulse driven hysteresis relay keeps the valve core self-locked to avoid 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 replenishment algorithm to call. This increases the slip within hundreds of 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 accomplished by the "depth-threshold mapping function" in the controller. This function is obtained in the experimental calibration stage by comparing the rate of increase of the oil supply pressure at different drilling depths with the arrival time of the peak torque wave of the power head. Its form is a linear decreasing curve with a low-end limit added.

[0077] For example, in factory bench and field shallow hole verification, when the depth is 0m, the threshold is denoted as X≈1.0MPas. -1 This value corresponds to the case with the shortest oil passage and the least elasticity. However, in the actual measurement of a 60m deep hole, after considering the combined increase in response hysteresis due to the expansion of the oil pipe volume and the measured hydraulic wave velocity, the threshold was reduced to X1≈0.25MPas. -1 ;

[0078] The real-time drilling depth d output by the depth sensor is substituted into the linear function ΔP(d) = Xk × d (k ≈ 0.012 MPa). -1 m -1 (Derived from multi-well average regression), 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] To avoid excessive oil draining in deep-hole applications that could cause a sudden drop in torque, the depth-dependent minimum torque Tmin(d) = T0 + α × d is introduced into the judgment condition (T0 is the nominal initial torque, α ≈ 50 N·mm). -1 (Based on rock sample drilling resistance test), only when the instantaneous pressure change rate is greater than ΔP(d) and the current torque T a The drain valve is opened only when Tmin(d) is greater than or equal to Tmin(d);

[0080] After the valve is closed, it can only be retried if ΔP falls back to (ΔP(d)-ε), where ε≈0.05MPas. -1 A step test was used to determine how to form a hysteresis band to prevent high-frequency switching.

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

[0082] Feedback module: When the pressure sensor detects that the oil supply pressure is stable within the range of 20 MPa ± 0.3 MPa for one second and the measured temperature of the thermocouple in the hydraulic coupler housing is not higher than 85 degrees Celsius, the main controller enters the oil replenishment mode. The working oil is replenished to the coupler in a quantitative manner of about 0.5 ml each time through a pulse micro-oil replenishment pump. The pulse interval is set to five seconds so that the oil can be fully dispersed and absorb heat and the slip measurement value can be re-converged.

[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 stops and the current oil filling amount is written to the power-off retention area to ensure the consistency of the benchmark for subsequent oil draining and oil filling algorithms.

[0084] If the pressure has been restored but the shell temperature is still above 85 degrees Celsius, the controller will keep the oil pump closed and expand the slip control window to three times the safe range, i.e., between 0.06 and 0.12. At this time, by maintaining the oil drain valve in a slightly open state, some oil continues to circulate externally for heat dissipation, and the temperature curve is checked every 500 milliseconds. Only when the temperature is below the threshold for five consecutive seconds will the oil drain valve be closed and the aforementioned micro-oil replenishment process be switched to gradually restore the original oil filling volume and pull the slip back to the safe zone.

[0085] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters and thresholds in the formulas are set by those skilled in the art according to the actual situation.

[0086] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. An adaptive speed control system for rotary drilling rigs based on pressure feedback, characterized in that, include: The data acquisition module acquires 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. Based on the slip, it obtains the actual torque value of the power head. Adjustment module: Adjusts engine throttle based on actual torque value and fuel supply pressure to keep fuel supply pressure within a preset stable pressure range and ensure that the power head speed reaches the target speed. The target speed is determined based on slip and pressure difference. The pressure difference represents the difference between 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 housing temperature of the hydraulic coupler is not higher than the preset value, the original oil filling amount is gradually restored according to the constant micro-oil replenishment method until the slip returns to the preset safe range; When the pressure returns to the stable pressure range and the housing of the hydraulic coupler exceeds the preset value, the slip is kept within the preset slip range until the housing temperature of the hydraulic coupler is not higher than the preset value. When the instantaneous rate of change of the oil supply pressure is greater than the preset impact threshold, the special oil drain valve of the hydraulic coupling is opened to discharge a predetermined proportion of working oil in order to increase the slip and weaken the peak torque transmitted to the power head. The actual torque value of the power head obtained based on slip includes: Obtain a pre-stored torque mapping curve, which is obtained from a bench calibration experiment with slip as the independent variable; Substituting the slip into the torque mapping curve, we obtain the torque coefficient A. Multiplying the torque coefficient A by the nominal torque constant of the power head mechanical structure, we obtain the actual torque value of the power head. Determining the target rotational speed includes: Substituting the slip into the first curve yields the first coefficient. The first reference curve has slip as the horizontal axis and speed correction coefficient as the vertical axis. Substitute the pressure difference value into the second curve to obtain the second coefficient. The second reference curve has the pressure difference value on the horizontal axis and the speed correction coefficient on the vertical axis. The preset arithmetic combination rules are executed to combine the first correction coefficient and the second correction coefficient into a comprehensive correction coefficient. The comprehensive correction coefficient is then multiplied by the nominal speed constant of the engine to obtain the target speed.

2. The adaptive speed control system for rotary drilling rigs based on pressure feedback according to claim 1, characterized in that, Obtaining the first curve includes: The engine speed B is defined as the nominal speed constant when the engine is under no-load conditions and the fuel supply pressure is at the center of the stable pressure range. With the engine maintaining its nominal speed constant and the oil supply pressure at the center of the stable pressure range, an external resistance force is applied by an external hydraulic brake to gradually change the speed of the power head and record the slip in real time. When the slip is a1 and the oil supply pressure deviates from the center value of the stable pressure range, the engine throttle is slowly reduced at a preset speed until the oil supply pressure returns to the center value of the stable pressure range, and the engine speed is read at this time. The engine speed at this time is compared with the nominal speed constant to obtain the speed correction coefficient a2, and the first coordinate point (a1, a2) is generated. The first coordinate point is then fitted to obtain the first curve.

3. The adaptive speed control system for rotary drilling rigs based on pressure feedback according to claim 2, 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 resistance to make the fuel supply pressure higher or lower than the center value of the stable pressure range, record the pressure difference b1, decrease 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.

4. The adaptive speed control system for rotary drilling rigs based on pressure feedback according to claim 3, characterized in that, The preset arithmetic combination rules include: When the first coefficient and the second coefficient have the same sign, the one with the larger absolute value is taken as the initial composite coefficient, and the one with the smaller absolute value is taken as the benchmark to offset and correct the initial composite coefficient according to a fixed ratio to obtain the comprehensive correction coefficient. When the signs of the first coefficient and the second coefficient are different, 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.

5. The adaptive speed control system for rotary drilling rigs 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: Map the pressure difference to the first throttle correction value; Calculate the difference between the target speed and the power head speed, denoted as the speed deviation, and map the speed deviation to the second throttle correction amount; Map the actual torque value to a torque proportionality coefficient; The first throttle correction amount is added to the second throttle correction amount to obtain the composite throttle correction amount. The torque proportional coefficient is multiplied by the composite throttle correction amount to obtain the comprehensive throttle correction amount. The engine throttle is adjusted according to the comprehensive throttle correction amount.

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