Energy-saving control method for rotary drilling rig

Abstract

The present invention discloses an energy-saving control method for a rotary drilling rig, and the implementation process thereof is as follows: installing a sensor, obtaining the pressure of a power head hydraulic motor, the flow rate of the power head hydraulic motor, and the pressure of a hydraulic pump, and reading the engine speed and the throttle opening through a CAN bus at the same time; determining the working condition according to the load of the power head hydraulic motor, and obtaining the ideal working point of the engine by using a universal characteristic curve; the engine ECU adjusts the engine speed through PID control to make the engine at an ideal working point, and achieves matching of the engine output power and the load; while adjusting the engine speed, adjusting the hydraulic pump displacement through fuzzy PID control to achieve matching of the hydraulic pump absorption power and the engine output power. Through the global power matching relationship between the engine, the hydraulic pump, and the load, the energy utilization rate of the whole machine is improved, and energy-saving control of the rotary drilling rig is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of rotary drilling rigs, and in particular to an energy-saving control method for rotary drilling rigs. Background Art

[0002] The rotary drilling rig is a highly integrated pile foundation construction machine, which is widely used in the foundation bored pile projects of railways, highway bridges, municipal construction, high-rise buildings, etc. During the drilling operation of the rotary drilling rig, due to the harsh working environment and large load changes of the rotary drilling rig, the engine speed and power will fluctuate, making it impossible for the engine to stably operate in the economic working area, resulting in a mismatch between the hydraulic pump absorption power and the engine output power, resulting in a large amount of overflow loss. At the same time, the original control method of the engine and the hydraulic pump leads to a large amount of energy loss, including: engine energy loss, loss caused by poor power matching between the engine and the hydraulic system, overflow loss of the multi-way valve and throttling loss. Therefore, it is necessary to adjust the working point of the engine according to different working conditions and loads to give full play to its power and economy, and at the same time adjust the displacement of the hydraulic pump to achieve the matching of the hydraulic pump absorption power and the engine output power, so as to improve the energy utilization rate of the whole machine.

[0003] In the prior art, most of them only consider the power matching between the engine and the hydraulic pump or the matching between the hydraulic pump and the load, but do not consider the mutual influence between the engine, the hydraulic pump and the load, thus resulting in poor energy saving effect. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defect of the rotary drilling rig in the prior art that the energy saving is poor during the drilling operation, and to provide an energy-saving control method for the rotary drilling rig.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A rotary drilling rig energy-saving control method, the rotary drilling rig energy-saving control method comprising:

[0007] S1: Install sensors to obtain real-time data: Install pressure sensors and flow sensors at the hydraulic motor of the power head to obtain real-time hydraulic motor pressure and flow of the power head hydraulic motor; install pressure sensors at the outlet of the hydraulic pump to obtain the hydraulic pump pressure; at the same time, obtain the throttle opening and engine speed through the CAN bus of the rotary drilling rig;

[0008] S2: Determine the working condition according to the load of the hydraulic motor of the maneuvering head, determine the engine output power according to the current working condition, and determine the speed n, torque according to the universal characteristic curve M , to obtain the ideal operating point of the engine;

[0009] S3: The engine ECU sets the throttle calibration value according to the obtained ideal engine operating point, and adjusts the engine speed through PID control; the engine ECU obtains the engine speed signal to realize feedback control of the engine speed, so that the engine is at the ideal operating point and the engine output power is matched with the load;

[0010] S4: Through the fuzzy PID control algorithm, the optimal adjustment parameters of the proportional valve of the hydraulic pump are obtained, the proportional valve control current is output, the opening size of the proportional valve of the variable cylinder is controlled, and the driving pressure size and direction of the variable cylinder are changed to achieve real-time matching of the engine output power and the hydraulic pump absorption power.

[0011] Furthermore, it also includes determining the working condition by judging the relationship between the pressure of the hydraulic motor of the power head and the first load limit value and the second load limit value, wherein the first load limit value is less than the second load limit value;

[0012] When the hydraulic motor pressure of the power head is less than the first load limit value, the engine is in an idle and no-load condition, and the engine output power is set to the minimum engine output power;

[0013] When the hydraulic motor pressure of the power head is greater than or equal to the first load limit value and less than the second load limit value, the engine is in a light load or medium load condition, and the ideal working point of the engine is determined according to the engine optimal fuel consumption line;

[0014] When the hydraulic motor pressure of the power head is greater than or equal to the second load limit value, it is in a heavy load condition, and the engine power is set to the maximum engine output power.

[0015] Furthermore, while the engine speed is controlled according to the load, the hydraulic pump displacement is also controlled according to the engine speed, thereby achieving global power matching of the engine, the hydraulic pump, and the load.

[0016] The positive and progressive effects of the present invention are: judging the working condition of the rotary drilling rig at this time according to the pressure at the hydraulic motor of the power head, and determining the ideal working point of the engine according to the current working condition, and adjusting the engine speed through the PID control system so that the engine is at the ideal working point, thereby achieving the matching of the engine output power and the load; at the same time, adjusting the hydraulic pump through the PID control system so that the hydraulic pump completely absorbs the output power of the engine, thereby achieving the matching of the engine output power and the absorbed power of the hydraulic pump, so that power matching is achieved among the engine, the hydraulic pump and the load, the energy utilization rate of the rotary drilling rig is improved, and the energy saving effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic flow chart of a rotary drilling rig energy-saving control method according to an embodiment of the present application;

[0018] Figure 2 A schematic flow chart of a method for determining an ideal operating point of an engine according to an embodiment of the present application;

[0019] Figure 3 This is a flow chart of PID control according to an embodiment of the present application;

[0020] Figure 4 A schematic diagram of the conversion process of the engine and the hydraulic system according to an embodiment of the present application;

[0021] Figure 5 Another schematic diagram of the PID control process according to an embodiment of the present application. DETAILED DESCRIPTION

[0022] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0023] like Figure 1-5 As shown, a rotary drilling rig energy-saving control method comprises the following steps:

[0024] S1: Install a pressure sensor and a flow sensor at the power head hydraulic motor to obtain the real-time power head hydraulic motor pressure p mi And the power head hydraulic motor flow Q mi , thus calculating the total power N of the real-time power head hydraulic motor m :

[0025]

[0026] Where n is the number of hydraulic motors in the power head.

[0027] Install a pressure sensor at the outlet of the hydraulic pump to obtain the hydraulic pump pressure P p ; At the same time, the throttle opening is obtained through the rotary drilling rig CAN bus and engine speed n e .

[0028] S2: When the rotary drilling rig is working, the working condition is judged according to the different loads of the hydraulic motor of the power head. The load feedback system transmits it to the engine ECU, so that it is judged according to the total power N of the hydraulic motor of the power head. m Select the corresponding power mode according to the different conditions to adjust the throttle opening of the engine to achieve the ideal working point.

[0029] like Figure 2As shown, the first load limit value is p1, and the second load limit value is p2, wherein the first load limit value p1 is less than the second load limit value p2. When the detected load is less than p1, it is considered to be an idle no-load condition; when the detected load is between p1 and p2, it is considered to be a light load or medium load condition; when the detected load is greater than p2, it is considered to be a heavy load condition.

[0030] When the rotary drilling rig is in an idling and no-load condition, the pressure detected by the pressure sensor at the power head hydraulic motor is less than p1. At this time, the engine output power only needs to meet the minimum load requirement for the normal operation of the rotary drilling rig, and the engine power output is minimum; when the rotary drilling rig is in a light-load or medium-load condition, according to the universal characteristic curve of the engine, there is an optimal working point in any state within its working range to make the system work most efficiently at this point and have the best energy-saving effect. All points are connected to form an optimal fuel consumption line that changes with the load. According to the optimal fuel consumption line, the ideal working point of the engine can be obtained; when the rotary drilling rig is in a heavy-load condition, the pressure detected by the pressure sensor at the power head hydraulic motor is greater than or equal to p2. At this time, the engine power is set to its maximum allowable power point, and the engine speed reaches the maximum.

[0031] S3: Figure 3 As shown in the figure, the control of the engine can be simplified to a proportional + integral + pure hysteresis system, which is adjusted by PID control. In this system, the controller will obtain the actual throttle value detected by the throttle position sensor. Throttle calibration value with ideal working point The comparison is made to control the engine speed.

[0032] PID control uses the deviation between the given value and the actual output value to form a control quantity through a linear combination of proportion (P), integration (I), and differentiation (D) to control the control object. The equation is:

[0033]

[0034] Where, e(t) is the deviation between the target speed and the actual speed; u(t) is the target control amount; K P is the proportionality coefficient, T I is the integration time constant, T D is the differential time constant.

[0035] Since the increment of the actuator is to be controlled, an incremental algorithm can be used. The engine is a nonlinear control object. Therefore, the application of the integral link in the control will cause a large deviation in the system output when the process starts, ends or changes. It is also easy to cause integral accumulation, causing system overshoot, thereby causing system oscillation and damage to the engine. Therefore, an integral separation algorithm is used. In the case of large deviations, the integral effect is reduced or even shielded to avoid overshoot, and in the case of small deviations, the integral effect is increased to eliminate static errors and improve control accuracy. Its control model is:

[0036]

[0037] In the formula, e(k) is the deviation between the target value and the actual value; u(k) is the target control amount; K P is the proportionality coefficient; K i is the integral coefficient; K d is the differential coefficient; α is the weighting coefficient, 0≤α≤1, and the value can be taken according to the size of the deviation to change the size of the integral effect.

[0038] S4: Figure 4-Figure 5 As shown, while the engine is controlling the speed, the optimal adjustment parameters of the proportional valve of the hydraulic pump are controlled, the proportional valve control current is output, the opening size of the proportional valve of the variable cylinder is adjusted, the driving pressure size and direction of the variable cylinder are changed, the displacement changes with the engine speed, the engine power is fully absorbed, and the output power of the engine is matched with the absorption power of the hydraulic pump.

[0039] Engine output power N e for

[0040] N e =M e n e (4)

[0041] Where M e is the engine output torque, n e is the engine speed.

[0042] Hydraulic pump absorption power N p for

[0043] N P =P P Q P =P P V P n p =M P n p (5)

[0044] Where P p is the hydraulic pump outlet pressure, Qp is the hydraulic pump output flow, V p is the displacement of the hydraulic pump, n p is the hydraulic pump speed, M p Absorbs torque for the hydraulic pump.

[0045] like Figure 4 As shown, since the engine output shaft and the hydraulic pump shaft are directly and rigidly connected through a coupling, n e =n p , if the efficiency of mechanical transmission is not considered and M e =M p When the engine output power N e The hydraulic pump absorbs power N p equal, the system has no power loss. When the load changes, n e and P p Adjust the hydraulic pump displacement V in real time as it changes p , so that it absorbs torque and always matches the engine output torque, thus achieving power matching between the engine and the hydraulic pump.

[0046] The engine-hydraulic pump system of the rotary drilling rig drilling operation is a complex system with time-varying, large lag and nonlinear characteristics. It is very difficult to establish a mathematical model for system control and regulation that meets the requirements of timely regulation, and the power matching process of the system requires follow-up regulation.

[0047] like Figure 5 As shown, the fuzzy PID control method is used to realize the hydraulic pump displacement adjustment, and the block diagram of the engine-hydraulic pump fuzzy control system is obtained.

[0048] By analyzing the working principle of the rotary drilling rig power system, a two-dimensional fuzzy controller is selected. There are two input quantities, one is the difference between the actual value and the set value, and the other is the change of this deviation relative to the previous deviation. After fuzzification, reasoning of control rules, and clarification of fuzzy quantities, the required control quantity is output. The relationship between the input and output can be obtained as follows:

[0049] u(k)=k p ·e(k)+k I ec(k)+k D ·[ec(k)-ec(k-1)]+u(k-1) (6)

[0050] Where u(k) is the output value of the controller; e(k) is the control current deviation; ec(k) is the control current deviation increment; k p is the proportionality coefficient; k I is the integral coefficient; k D is the differential coefficient.

[0051] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for energy-saving control of a rotary drilling rig, wherein the method is to control the matching of engine output power and hydraulic pump absorption power when the rotary drilling rig is in service, and is characterized in that: Here are the steps: S1: Install sensors to obtain real-time data: Install pressure sensors and flow sensors at the hydraulic motor of the power head to obtain real-time hydraulic motor pressure and flow of the power head hydraulic motor; install pressure sensors at the outlet of the hydraulic pump to obtain the hydraulic pump pressure; at the same time, obtain the throttle opening and engine speed through the CAN bus of the rotary drilling rig; S2: Determine the working condition according to the load of the hydraulic motor of the power head, determine the engine output power according to the current working condition, determine the speed n and torque M according to the universal characteristic curve, and obtain the ideal working point of the engine; Determine the working condition by judging the relationship between the pressure of the hydraulic motor of the power head and the first load limit value and the second load limit value, wherein the first load limit value is less than the second load limit value; When the hydraulic motor pressure of the power head is less than the first load limit value, it is in an idle and no-load condition, and the engine output power is set to the minimum engine output power; When the hydraulic motor pressure of the power head is greater than or equal to the first load limit value and less than the second load limit value, the engine is in a light load or medium load condition, and the ideal working point of the engine is determined according to the engine optimal fuel consumption line; When the hydraulic motor pressure of the power head is greater than or equal to the second load limit value, it is in a heavy load condition, and the engine power is set to the maximum engine output power; S3: The engine ECU sets the throttle calibration value according to the obtained ideal engine operating point, and adjusts the engine speed through PID control; the engine ECU obtains the engine speed signal to realize feedback control of the engine speed, so that the engine is at the ideal operating point and the engine output power is matched with the load; S4: Obtain the best adjustment parameters for controlling the hydraulic pump proportional valve through the fuzzy PID control algorithm, output the hydraulic pump proportional valve control current, control the opening size of the variable cylinder proportional valve, and change the driving pressure size and direction of the variable cylinder to achieve real-time matching between the engine output power and the hydraulic pump absorption power; The engine output power is N e =M e n e Where M e is the engine output torque, n e is the engine speed; Hydraulic pump absorption power N p for N P =P P Q P =P P V P n P =M P n p Where P p is the hydraulic pump outlet pressure, Q p is the hydraulic pump output flow, V p is the hydraulic pump displacement, n p is the hydraulic pump speed, M p Absorbs torque for hydraulic pumps; The engine output shaft and the hydraulic pump shaft are directly connected rigidly through a coupling, so n e =n p , if the efficiency of mechanical transmission is not considered and M e =M p When the engine output power N e The hydraulic pump absorbs power N p equal, the system has no power loss; when the load changes, n e and P p Adjust the hydraulic pump displacement V in real time as it changes p , so that it absorbs torque and always matches the engine output torque, achieving power matching between the engine and the hydraulic pump.

2. The energy-saving control method for a rotary drilling rig according to claim 1, characterized in that: While controlling the engine speed according to the load, the hydraulic pump displacement is also controlled according to the engine speed to achieve global power matching of the engine, hydraulic pump and load.

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