Vehicle-mounted drilling machine electric control positive flow lifting hydraulic system and valve-pump collaborative control method

Abstract

The application discloses a vehicle-mounted drilling machine electric control positive flow lifting hydraulic system and a valve-pump cooperative control method, and belongs to the technical field of hydraulic engineering machinery. The vehicle-mounted drilling machine electric control positive flow lifting hydraulic system comprises a control unit and a lifting oil cylinder. The lifting oil cylinder comprises a rodless cavity and a rod cavity. The hydraulic rod of the lifting oil cylinder is provided with a load. An encoder is arranged on the hydraulic rod. The lifting oil cylinder is sequentially connected with an electric control positive flow valve unit, an electric control positive flow pump unit and an oil tank through an overflow valve group. The system adopts feedforward feedback closed-loop control. The speed error of the vehicle-mounted drilling machine lifting hydraulic system is taken as the input of the feedback. After calculation, the error correction amount of the electric control positive flow pump unit is used to adjust the flow. The set speed of the vehicle-mounted drilling machine lifting hydraulic system is taken as the input of the feedforward. After calculation, the feedforward advance amount of the displacement control of the main valve core of the closed center type multi-way valve is used to match the response time of the electric control positive flow valve unit and the electric control positive flow pump unit, eliminate the overflow loss caused by the pressure impact in front of the valve, and achieve the purpose of improving the response speed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydraulic engineering machinery, and particularly relates to a vehicle-mounted drilling machine electric control positive flow lifting hydraulic system and a valve-pump cooperative control method. BACKGROUND

[0002] The ground drilling technology can not only realize efficient exploitation of underground resources, but also realize direct connection between the ground and an underground disaster area after a collapse accident of the underground engineering, and then provide life supplies and improve a rescue channel for trapped personnel.

[0003] The vehicle-mounted drilling machine is main equipment for ground drilling, and includes a vehicle-mounted drilling machine feeding system and a drilling machine lifting hydraulic system. The working performance of the drilling machine lifting hydraulic system directly affects drilling efficiency. A load sensing system is currently used in a large vehicle-mounted drilling machine. However, due to the presence of a pressure compensation valve, the system has certain throttling loss. Moreover, the control oil way of the load sensing pump comes from the pressure of an actuator, and has certain hysteresis.

[0004] The prior art CN102979499A discloses a vehicle-mounted drilling machine operation control system and method, which includes a control unit, a detection unit, a switch unit, an upper vehicle operation mode switching unit, a gearbox controller and a transfer case electromagnetic valve unit. The switch unit includes a power take-off switch subunit. The transfer case electromagnetic valve unit includes a transfer case power take-off electromagnetic valve and a transfer case neutral electromagnetic valve. The detection unit is used for detecting the brake state of the vehicle-mounted drilling machine and the gear state of the transfer case. When the vehicle-mounted drilling machine is in the brake state, the power take-off switch subunit sends a power take-off signal to the control unit, and the transfer case power take-off electromagnetic valve and the transfer case neutral electromagnetic valve are electrified at the same time. At this time, the transfer case is in the neutral state. The neutral signal is sent to the control unit by the detection unit, the control unit generates a driving signal, the driving signal is transmitted to the gearbox controller through the upper vehicle operation mode switching unit, and the gearbox controller converts the output mode into the upper vehicle operation mode. The prior art uses electromagnetic valves to control the oil way, but cannot withstand large force, is prone to oil leakage, and has delayed response. SUMMARY

[0005] The present application designs a vehicle-mounted drilling machine electric control positive flow lifting hydraulic system and a valve-pump cooperative control method to solve the problems of high energy consumption and slow response of the current vehicle-mounted drilling machine lifting hydraulic system. Compared with a conventional open center type multi-way valve and a positive flow pump combined into a positive flow system, the closed center type multi-way valve does not have a bypass throttle, and uses an electric signal as a control signal of the variable pump, which has higher energy saving and response speed. At the same time, the valve-pump cooperative matching effectively reduces the pressure impact of the system. The system response speed is effectively improved, the throttling loss is reduced, the pressure impact is reduced, and the control performance of the vehicle-mounted drilling machine lifting system is improved.

[0006] To achieve the above technical purposes, the present application discloses a kind of vehicle-mounted drilling rig electric control positive flow hydraulic system,

[0007] Including control unit and lift cylinder, lift cylinder includes rodless cavity and rod cavity, the hydraulic rod of lift cylinder is with load, encoder is equipped on the hydraulic rod, lift cylinder is sequentially connected with electric control positive flow valve unit, electric control positive flow pump unit and oil tank by overflow valve group;

[0008] Control unit includes the controller connected with control handle;

[0009] Overflow valve group includes overflow valve a and overflow valve b;

[0010] Electric control positive flow valve unit includes closed center type multi-way valve, pilot proportional pressure reducing valve a and pilot proportional pressure reducing valve b;

[0011] Electric control positive flow pump unit includes engine, variable pump, adjusting mechanism, proportional pilot valve and oil supplement pump, wherein variable pump, oil supplement pump and engine are coaxially connected by connecting shaft, the displacement of variable pump is controlled by the hydraulic rod of adjusting mechanism;

[0012] Pressure, flow sensor is equipped on the inlet and outlet of rodless cavity and rod cavity of lift cylinder and variable pump outlet, and pressure, flow sensor is connected with controller by cable and sends data, and encoder is connected with controller by cable and sends data;Controller is connected with pilot proportional pressure reducing valve a, pilot proportional pressure reducing valve b and proportional pilot valve respectively by cable and sends control data;

[0013] Wherein, the oil inlet of variable pump is connected with oil tank, and the oil outlet of variable pump is respectively connected with one-way valve and overflow valve c, and variable pump is connected with the oil inlet of closed center type multi-way valve by one-way valve, and the oil outlet of pilot proportional pressure reducing valve a and pilot proportional pressure reducing valve b is connected with the control oil way of closed center type multi-way valve on both sides, and the two oil outlets of closed center type multi-way valve are connected with the rodless cavity and rod cavity of lift cylinder respectively, and overflow valve a is connected on the pipeline connected with rodless cavity, and overflow valve b is connected on the pipeline connected with rod cavity;The oil return end of overflow valve a, overflow valve b, closed center type multi-way valve, overflow valve c is connected with oil tank;

[0014] Wherein, oil supplement pump is connected with pilot proportional pressure reducing valve a, pilot proportional pressure reducing valve b and proportional pilot valve respectively by pipeline, and the oil outlet of proportional pilot valve is connected with the rodless cavity of adjusting mechanism, and the oil pressure of rodless cavity of adjusting mechanism is controlled to adjust variable pump, and the oil return end of pilot proportional pressure reducing valve a, pilot proportional pressure reducing valve b and proportional pilot valve is connected with oil tank;

[0015] The oil provided by the oil supplement pump respectively passes through the pilot proportional pressure reducing valve a and the pilot proportional pressure reducing valve b to supply oil to both sides of the closed center multi-way valve, so as to adjust the gear of the closed center multi-way valve, and further control the moving direction and speed of the lifting and lowering cylinder; when the pressure of the truck-mounted drilling rig lifting and lowering hydraulic system exceeds the preset value, the oil at the outlet of the variable pump returns to the oil tank through the overflow valve c, and when the load exceeds the preset value, the oil output by the closed center multi-way valve returns to the oil tank through the overflow valve a and the overflow valve b, so as to ensure the safety of the hydraulic elements.

[0016] To realize the electric control positive flow high-precision speed control of the truck-mounted drilling rig, the feedforward-feedback closed loop control method is adopted, the feedback takes the speed error of the truck-mounted drilling rig lifting and lowering hydraulic system as input, and after calculation, an error correction quantity is given to the electric control positive flow pump unit to adjust the flow; the feedforward takes the set speed of the truck-mounted drilling rig lifting and lowering hydraulic system as input, and after calculation, a feedforward advance quantity is given to the closed center multi-way valve main valve spool displacement control, so as to match the response time of the electric control positive flow valve unit and the electric control positive flow pump unit, eliminate the overflow loss caused by the pressure impact in front of the valve, and achieve the purpose of improving the response speed.

[0017] Further, the closed center multi-way valve is a three-position five-way reversing valve, when the operation control handle acts, the electric signals output by the controller control the opening size of the pilot proportional pressure reducing valve a and the pilot proportional pressure reducing valve b, so as to control the position of the closed center multi-way valve; the oil at the outlet of the variable pump returns to the oil tank through the one-way valve to supply oil to the oil inlet of the closed center multi-way valve, when the closed center multi-way valve is in the middle position, the oil return port of the closed center multi-way valve has no additional flow to return to the oil tank, so as to ensure the energy saving efficiency and response speed of the whole system, when the closed center multi-way valve is in the left position, the rodless cavity of the lifting and lowering cylinder is supplied with oil and the rod cavity returns oil, to complete the lifting action; when the closed center multi-way valve is in the right position, the rod cavity of the lifting and lowering cylinder is supplied with oil and the rodless cavity returns oil, to complete the lowering action.

[0018] Further, the overflow valve a, the overflow valve b and the overflow valve c are used to automatically judge whether the pressure of the lifting and lowering hydraulic system exceeds the preset pressure, wherein the overflow valve c is used as a safety valve, the set pressure of the overflow valve c is higher than that of the overflow valve a and the overflow valve b, further ensuring that the whole lifting and lowering hydraulic system will not have the phenomenon of excessively high pressure, that is, the highest pressure of the lifting and lowering hydraulic system is the set value of the overflow valve c; the set pressure of the overflow valve a and the overflow valve b is slightly smaller than that of the overflow valve c, so as to protect the lifting and lowering cylinder from being damaged.

[0019] Further, when the handle is operated, the signal is transmitted to the controller, and the pressure and flow signals of the two chambers of the lifting cylinder and the pressure and flow signals at the outlet of the variable pump are transmitted to the controller through the cable, and the controller transmits the control signal to the proportional pilot valve, and then controls the opening size of the proportional pilot valve; the oil provided by the oil supplement pump enters the rodless chamber of the adjusting mechanism through the proportional pilot valve, and the position of the hydraulic rod of the adjusting mechanism can adjust the displacement of the variable pump; by simultaneously controlling the opening size of the closed center multi-way valve and the flow of the variable pump through the controller, the pressure and flow of the lifting cylinder are adjusted to adapt to the time-varying load.

[0020] A working method of the vehicle-mounted drilling rig electric control positive flow lifting hydraulic system, comprising the following steps:

[0021] After the vehicle-mounted drilling rig electric control positive flow lifting hydraulic system starts to work, the engine is started, and the engine drives the variable pump and the oil supplement pump to work through the connecting shaft, and oil is supplied to the closed center multi-way valve, the lifting cylinder, and the pilot proportional pressure reducing valve a, the pilot proportional pressure reducing valve b, and the proportional pilot valve;

[0022] When the lifting cylinder is lifted, the rodless chamber needs to be filled with oil, and the rod chamber needs to return oil: the signal input by the control handle is transmitted to the controller, and the electric signal output by the controller controls the proportional pressure reducing valve and the proportional pilot valve, the closed center multi-way valve works in the left position under the action of the proportional pressure reducing valve, the high-pressure oil pumped by the variable pump enters the rodless chamber of the lifting cylinder through the closed center multi-way valve, and the oil in the rod chamber of the lifting cylinder returns to the oil tank through the oil return port of the closed center multi-way valve;

[0023] When the lifting cylinder is lowered, the rod chamber needs to be filled with oil, and the rodless chamber needs to return oil: the signal input by the control handle is transmitted to the controller, and the electric signal output by the controller controls the proportional pressure reducing valve and the proportional pilot valve, the closed center multi-way valve works in the right position under the action of the proportional pressure reducing valve, the high-pressure oil pumped by the variable pump enters the rod chamber of the lifting cylinder through the closed center multi-way valve, and the oil in the rodless chamber of the lifting cylinder returns to the oil tank through the oil return port of the closed center multi-way valve;

[0024] During the lifting process of the lifting cylinder, the controller analyzes the signal input by the control handle, the pressure and flow signals in the rodless chamber and the rod chamber of the lifting cylinder, and the pressure and flow signals at the outlet of the variable pump, and adjusts the position of the hydraulic rod of the adjusting mechanism to adjust the displacement of the variable pump, since the maximum pilot pressure value determines the flow of the system; at the same time, the controller calculates the opening size of the closed center multi-way valve matched with the displacement of the variable pump, and adjusts the working position and opening size of the closed center multi-way valve through the pilot proportional pressure reducing valve a and the pilot proportional pressure reducing valve b;

[0025] When the proportional pilot valve works in the left position, the control oil enters the rodless cavity of the adjusting mechanism, and the hydraulic rod of the adjusting mechanism adjusts the variable pump to reduce the flow rate; when the proportional pilot valve works in the right position, the rodless cavity of the adjusting mechanism is connected to the oil tank, and the hydraulic rod of the adjusting mechanism adjusts the variable pump to increase the flow rate under the action of the built-in spring, thereby ensuring the matching degree of the system output flow rate and the required flow rate and improving the energy saving of the system.

[0026] A pump-valve cooperative control method of a truck-mounted drilling rig lifting and lowering hydraulic system, the controller comprising a feedforward controller and a feedback controller, since the purpose of the controller is to match the flow rate of the variable pump and the through-flow of the closed-center multi-way valve, and to be proportional to the maximum pressure of the handle, and in order to reduce pressure impact, the response speed of the closed-center multi-way valve should be improved as much as possible, therefore the variable pump uses the feedback controller to ensure that the output flow rate of the variable pump is consistent with the calculated value of the controller, and the closed-center multi-way valve uses a composite controller composed of the feedforward controller and the feedback controller, wherein the feedforward controller is used to improve the response speed of the closed-center multi-way valve, and the feedback controller is used to ensure that the opening of the closed-center multi-way valve is consistent with the calculated value of the controller;

[0027] The specific steps are as follows:

[0028] The controller compares the input signal of the control handle, calculates the speed r a (t) of the lifting system of the truck-mounted drilling rig at this time, and the difference between the feedback speed signal v a of the hydraulic rod of the lifting and lowering oil cylinder and the set speed r a (t) is e a (t), at this time e a (t) is calculated by the feedback controller to generate a corresponding output voltage value u a1 (t) to adjust the output flow rate of the variable pump; the set speed r a (t) of the lifting oil cylinder is calculated by the feedforward controller to generate a feedforward signal, which is superimposed with the feedback signal generated by the feedback controller to generate a corresponding output voltage value u a2 (t), and the output voltage value u a2 (t) is used to adjust the opening size of the closed-center multi-way valve; the output flow rate of the variable pump is matched with the opening of the closed-center multi-way valve to adjust the lifting and lowering oil cylinder.

[0029] Further, the truck-mounted drilling rig electric control positive flow lifting and lowering hydraulic system is used to control the feeding of the truck-mounted drilling rig, and the controller used comprises a feedforward controller and a feedback controller, a feedforward-feedback closed-loop control method is adopted, and the speed error signal of the truck-mounted drilling rig electric control positive flow lifting and lowering hydraulic system is obtained in advance;

[0030] The feedback controller is a proportional integral derivative control PID, the feedforward controller is a combination of a differential element and a proportional element, and the control parameters are respectively a feedforward differential coefficient kv and feedforward proportional coefficient k f ; feedback controller takes the speed error signal of the system as input, and calculates an error correction amount for the electro-hydraulic proportional pump unit through the PID controller to adjust the flow;

[0031] The feedforward controller takes the set speed of the electro-hydraulic proportional pump unit of the truck-mounted drilling rig as input, and calculates a feedforward advance amount for the displacement control of the main valve spool of the closed-center multi-way valve, so as to match the response time of the pump and valve, eliminate the overflow loss caused by the pressure impact in front of the valve, and achieve the purpose of improving the response speed of the system.

[0032] Specifically, the truck-mounted drilling rig controlled by the electro-hydraulic proportional pump unit of the truck-mounted drilling rig is set to a target drilling speed r a (t), the encoder detects the actual speed v a of the lifting cylinder, and compares and calculates the error speed signal e a (t) after the input target drilling speed r a (t) is compared, and the feedback control signal u a1 (t) is generated after the feedback controller is processed; at the same time, the input target drilling speed r a (t) is processed by the feedforward controller to generate a feedforward control signal, which is added to the feedback control signal processed by the PID controller to obtain the superimposed control signal u a2 (t); finally, the feedback control signal u a1 (t) acts on the pilot control end of the proportional pump to control the displacement of the proportional pump, and the superimposed control signal u a2 (t) acts on the valve opening of the proportional valve.

[0033] The expression of the feedback control signal u a1 (t) is as follows:

[0034]

[0035] The expression of the superimposed control signal u a2 (t) is as follows:

[0036]

[0037] In the formula, k p is the proportional coefficient, e a (t) is the speed error, T i is the integral time constant, T d is the differential time constant, k v is the feedforward differential coefficient, and k f is the feedforward proportional coefficient.

[0038] Beneficial effects: The valve-pump coordinated control system for lifting hydraulic rigs and its control method proposed in this invention adopts an electrically controlled positive flow system based on a closed-center multi-way valve. Since there is no bypass throttling, the energy efficiency and response speed of the system can be effectively improved. At the same time, the feedforward and feedback composite control method proposed for the new system can effectively reduce pressure shocks, which is of great significance for the performance optimization of the lifting hydraulic system for truck-mounted drilling rigs. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the electrically controlled positive flow lifting hydraulic system for the vehicle-mounted drilling rig in an embodiment of the present invention.

[0040] Figure 2 This is a schematic diagram of the valve-pump coordinated control method of the vehicle-mounted drilling rig in an embodiment of the present invention.

[0041] In the diagram: 1-Control handle, 2-Controller, 3-Lifting and lowering cylinder, 4-Encoder, 5-Relief valve a, 6-Relief valve b, 7-Closed-center multi-way valve, 8-Proportional pressure reducing valve a, 9-Proportional pressure reducing valve b, 10-Check valve, 11-Engine, 12-Connecting shaft, 13-Variable pump, 14-Adjusting mechanism, 15-Proportional pilot valve, 16-Maintenance pump, 17-Relief valve c, 18-Fuel tank. Detailed Implementation

[0042] The invention will now be further described with reference to the accompanying drawings.

[0043] like Figure 1 As shown, this invention discloses an electrically controlled positive flow lifting hydraulic system for a vehicle-mounted drilling rig and a valve-pump coordinated control method, including a control handle 1, a controller 2, a lifting cylinder 3, an encoder 4, an overflow valve a5, an overflow valve b6, a closed-center multi-way valve 7, a proportional pressure reducing valve a8, a proportional pressure reducing valve b9, a check valve 10, an engine 11, a connecting shaft 12, a variable pump 13, an adjusting mechanism 14, a proportional pilot valve 15, a replenishing pump 16, an overflow valve c17, and an oil tank 18.

[0044] The diesel engine 11, the variable pump 13 and the compensation pump 16 are connected by the connecting shaft 12. The variable pump 13 is connected to the oil inlet of the closed center multi-way valve 7 through the one-way valve 10, and a branch oil circuit is connected to the oil tank 18 through the overflow valve c17. The two working oil ports of the closed center multi-way valve 7 are connected to the two cavities of the lift cylinder 3, and each oil circuit has a branch oil circuit connected to the oil tank 18 through the overflow valves 5 and 6. The compensation pump 16 is connected to the oil inlets of the two proportional pressure reducing valves 8 and 9 and the proportional pilot valve 15. The working oil ports of the two proportional pressure reducing valves 8 and 9 are connected to the two hydraulic control ports of the closed center multi-way valve 7. The working oil port of the proportional pilot valve 15 is connected to the rodless cavity of the adjusting mechanism 14, and the position of the hydraulic rod of the adjusting mechanism 14 directly controls the displacement of the variable pump 13. The control handle 1, the encoder 4, the pressure and flow signals of the lift cylinder 3 and the pressure and flow signals of the outlet of the variable pump 13 are connected to the controller 2 through cables, and the controller 2 is connected to the proportional control ends of the two proportional pressure reducing valves 8 and 9 and the proportional pilot valve 15 through cables.

[0045] The control method is as follows: after the truck-mounted drilling rig is started, the diesel engine 11 drives the variable pump 13 and the compensation pump 16 to work through the connecting shaft 12, and supplies oil to the system main oil circuit shown by the solid line and the control oil circuit shown by the dashed line. The input signals of the control handle 1, the feedback electrical signals of the encoder 4, the pressure and flow electrical signals of the two cavities of the lift cylinder 3 and the pressure and flow electrical signals of the outlet of the variable pump 13 are transmitted to the controller 2, and the electrical signals output by the controller 2 control the opening sizes of the two proportional pressure reducing valves 8 and 9 and the proportional pilot valve 15 shown by the dotted line.

[0046] When the lifting cylinder 3 needs to be lifted, the signal input by the control handle 1 is transmitted to the controller 2 at this time, the controller 2 sends an electric signal after calculation by the feedforward control algorithm, controls the proportional pressure reducing valve 8 to drive the closed center multi-way valve to move to the left position, the high pressure oil output by the variable pump 13 enters the rodless chamber of the lifting cylinder 3 through the closed center multi-way valve 7, and the oil in the rod chamber of the lifting cylinder 3 returns to the oil tank 18 through the closed center multi-way valve 7. If the flow at the outlet of the variable pump 13 is less than the required flow of the lifting cylinder 3, the electric signal sent by the controller 2 drives the proportional pilot valve 15 to work at the right position, the high pressure oil output by the compensation pump 16 enters the rodless chamber of the adjusting mechanism 14, the hydraulic rod of the adjusting mechanism 14 extends to increase the displacement of the variable pump 13, and meanwhile the controller 2 sends an electric signal after composite calculation by the feedforward control algorithm and the feedback control algorithm, controls the proportional pressure reducing valve 8 to drive the closed center multi-way valve to increase the opening, so as to improve the movement speed of the system through the cooperation of the pump valve. If the flow at the outlet of the variable pump 13 is greater than the flow at the inlet of the lifting cylinder 3, the electric signal sent by the controller 2 drives the proportional pilot valve 15 to work at the left position, the high pressure oil output by the compensation pump 16 enters the rod chamber of the adjusting mechanism 14, the hydraulic rod of the adjusting mechanism 14 retracts to reduce the displacement of the variable pump 13, and meanwhile the controller 2 sends an electric signal after composite calculation by the feedforward control algorithm and the feedback control algorithm, controls the proportional pressure reducing valve 9 to drive the closed center multi-way valve 7 to reduce the opening, so as to reduce the movement speed of the system through the cooperation of the pump valve.

[0047] When the lifting cylinder 3 needs to be lowered, the signal input by the control handle 1 is transmitted to the controller 2 at this time, the controller 2 sends an electric signal after calculation by the feedforward control algorithm, controls the proportional pressure reducing valve 9 to drive the closed center multi-way valve 7 to move to the right position, the high pressure oil output by the variable pump 13 enters the rod chamber of the lifting cylinder 3 through the closed center multi-way valve 7, and the oil in the rodless chamber of the lifting cylinder 3 returns to the oil tank 18 through the closed center multi-way valve 7. Similarly, if the flow at the outlet of the variable pump 13 is less than the required flow of the lifting cylinder 3, the electric signal sent by the controller 2 drives the proportional pilot valve 9 to work at the right position, the high pressure oil output by the compensation pump 16 enters the rodless chamber of the adjusting mechanism 14, the hydraulic rod of the adjusting mechanism 14 extends to increase the displacement of the variable pump 13, and meanwhile the controller 2 sends an electric signal after composite calculation by the feedforward control algorithm and the feedback control algorithm, controls the proportional pressure reducing valve 9 to drive the closed center multi-way valve 7 to increase the opening, so as to improve the movement speed of the system through the cooperation of the pump valve. If the flow at the outlet of the variable pump 13 is greater than the flow at the inlet of the lifting cylinder 3, the electric signal sent by the controller 2 drives the proportional pilot valve 15 to work at the left position, the high pressure oil output by the compensation pump 16 enters the rod chamber of the adjusting mechanism 14, the hydraulic rod of the adjusting mechanism 14 retracts to reduce the displacement of the variable pump 13, and meanwhile the controller 2 sends an electric signal after composite calculation by the feedforward control algorithm and the feedback control algorithm, controls the proportional pressure reducing valve 9 to drive the closed center multi-way valve 7 to reduce the opening, so as to reduce the movement speed of the system through the cooperation of the pump valve.

[0048] A pump-valve coordinated control method for a vehicle-mounted drilling rig lifting and lowering hydraulic system, wherein the controller 2 includes a feedforward controller and a feedback controller. Since the purpose of the controller 2 is to match the flow rate of the variable pump 13 with the flow rate of the closed-center multi-way valve 7 and to be proportional to the maximum pressure of the handle, and to reduce pressure shock, the response speed of the closed-center multi-way valve 7 should be maximized. Therefore, the variable pump 13 uses the feedback controller to ensure that the output flow rate of the variable pump 13 is consistent with the calculated value of the controller 2. The closed-center multi-way valve 7 uses a composite controller composed of the feedforward controller and the feedback controller. The feedforward controller is used to improve the response speed of the closed-center multi-way valve 7, and the feedback controller is used to ensure that the opening of the closed-center multi-way valve 7 is consistent with the calculated value of the controller 2.

[0049] The specific steps are as follows:

[0050] like Figure 2 As shown, the vehicle-mounted drilling rig's electrically controlled positive flow lifting hydraulic system is used to control the feed of the vehicle-mounted drilling rig. The controller 2 used includes a feedforward controller and a feedback controller. It adopts a feedforward-feedback closed-loop control method to obtain the speed error signal of the vehicle-mounted drilling rig's electrically controlled positive flow lifting hydraulic system in advance.

[0051] The feedback controller is a proportional-integral-derivative (PID) controller, and the feedforward controller is a combination of a derivative and a proportional element. The control parameters are the feedforward derivative coefficients k. v and feedforward proportional coefficient k f The control parameters are obtained in advance or preset based on experience. The feedback controller takes the system's speed error signal as input, and after calculation by the PID controller, it gives the electronically controlled positive flow pump unit an error correction amount to adjust the flow rate.

[0052] The feedforward controller takes the set speed of the electric positive flow lifting hydraulic system of the vehicle-mounted drilling rig as input. After calculation, it gives a feedforward advance to the valve core displacement control of the main valve of the closed center multi-way valve 7, so as to match the response time of the pump valve, eliminate the overflow loss caused by the pressure shock in front of the valve, and achieve the purpose of improving the system response speed.

[0053] Specifically: The target drilling speed r is set for the drilling rig controlled by the electrically controlled positive flow hydraulic system. a (t), encoder 4 detects the actual speed v of lifting cylinder 3. a and the input target drilling rate r a (t) The error velocity signal e is calculated after comparison and subtraction. a (t), which is processed by the feedback controller to generate a feedback control signal u a1 (t); simultaneously, the input target drilling speed r a(t) a feedforward control signal is generated by a feedforward controller, which is added to the feedback control signal processed by the PID controller to obtain a superimposed control signal u a2 (t) a feedback control signal u a1 (t) is used to control the displacement of the positive flow pump by acting on the pilot control end of the positive flow pump a2 (t) is used to control the valve opening of the positive flow valve

[0054] a feedback control signal u a1 (t) is expressed as follows:

[0055]

[0056] a superimposed control signal u a2 (t) is expressed as follows:

[0057]

[0058] wherein k p is a proportional coefficient, e a (t) is a speed error, T i is an integral time constant, T d is a differential time constant, k v is a feedforward differential coefficient, k f is a feedforward proportional coefficient.

Claims

1. An electric control positive flow hydraulic system of a truck-mounted drilling rig, characterized in that: it comprises a control unit and a lifting cylinder (3), the lifting cylinder (3) comprises a rodless cavity and a rod cavity, the hydraulic rod of the lifting cylinder (3) is provided with a encoder (4), and the lifting cylinder (3) is sequentially connected with an electric control positive flow valve unit, an electric control positive flow pump unit and an oil tank (18) through an overflow valve group; the control unit comprises a controller (2) connected with a control handle (1); the overflow valve group comprises an overflow valve a (5) and an overflow valve b (6); the electric control positive flow valve unit comprises a closed center multi-way valve (7), a pilot proportional pressure reducing valve a (8) and a pilot proportional pressure reducing valve b (9); the electric control positive flow pump unit comprises an engine (11), a variable pump (13), an adjusting mechanism (14), a proportional pilot valve (15) and a oil supplement pump (16), wherein the variable pump (13), the oil supplement pump (16) and the engine (11) are coaxially connected through a connecting shaft (12), and the hydraulic rod of the adjusting mechanism (14) controls the displacement of the variable pump (13); the rodless cavity and the rod cavity of the lifting cylinder (3) are provided with pressure and flow sensors at oil inlet and outlet ports, the pressure and flow sensors are connected with the controller (2) through a cable and send data, and the encoder (4) is connected with the controller (2) through a cable and sends data; the controller (2) is connected with the pilot proportional pressure reducing valve a (8), the pilot proportional pressure reducing valve b (9) and the proportional pilot valve (15) through cables and sends control data; wherein the oil inlet of the variable pump (13) is connected with the oil tank (18), the oil outlet of the variable pump (13) is respectively connected with a one-way valve (10) and an overflow valve c (17), the variable pump (13) is connected with the oil inlet of the closed center multi-way valve (7) through the one-way valve (10), the oil outlets of the pilot proportional pressure reducing valve a (8) and the pilot proportional pressure reducing valve b (9) are connected with control oil paths on both sides of the closed center multi-way valve (7), and the two oil outlets of the closed center multi-way valve (7) are connected with the rodless cavity and the rod cavity of the lifting cylinder (3), the pipeline connected with the rodless cavity is connected with the overflow valve a (5), and the pipeline connected with the rod cavity is connected with the overflow valve b (6); the oil return ends of the overflow valve a (5), the overflow valve b (6), the closed center multi-way valve (7) and the overflow valve c (17) are connected with the oil tank (18); wherein the oil supplement pump (16) is connected with the pilot proportional pressure reducing valve a (8), the pilot proportional pressure reducing valve b (9) and the proportional pilot valve (15) through pipelines, the oil outlet of the proportional pilot valve (15) is connected with the rodless cavity of the adjusting mechanism (14), the variable pump (13) is adjusted by controlling the oil pressure of the rodless cavity of the adjusting mechanism (14), and the oil return ends of the pilot proportional pressure reducing valve a (8), the pilot proportional pressure reducing valve b (9) and the proportional pilot valve (15) are connected with the oil tank (18). ​ ​ ​ ​ ​ ​ ​ ​ The oil provided by the oil supplement pump (16) respectively passes through the pilot proportional pressure reducing valve a (8) and the pilot proportional pressure reducing valve b (9) to supply oil to both sides of the closed center multi-way valve (7), so as to adjust the gear of the closed center multi-way valve (7), and then control the moving direction and speed of the lifting and lowering oil cylinder (3); when the pressure of the truck-mounted drilling rig lifting and lowering hydraulic system exceeds the preset value, the oil at the outlet of the variable pump (13) returns to the oil tank (18) through the overflow valve c (17); when the load exceeds the preset value, the oil output by the closed center multi-way valve (7) returns to the oil tank (18) through the overflow valve a (5) and the overflow valve b (6), so as to ensure the safety of the hydraulic elements; In order to realize the electric control positive flow high-precision speed control of the truck-mounted drilling rig, the feed-back closed loop control method is adopted, the speed error of the truck-mounted drilling rig lifting and lowering hydraulic system is fed back as the input, an error correction amount is given to the electric control positive flow pump unit after calculation to adjust the flow, the set speed of the truck-mounted drilling rig lifting and lowering hydraulic system is fed forward as the input, a feed-forward advance amount is given to the main valve core displacement control of the closed center multi-way valve (7) after calculation, so as to match the response time of the electric control positive flow valve unit and the electric control positive flow pump unit, eliminate the overflow loss caused by the pressure impact in front of the valve, and achieve the purpose of improving the response speed; The closed center multi-way valve (7) is a three-position five-way reversing valve, when the operation control handle (1) is actuated, the electric signals output by the controller (2) control the opening size of the pilot proportional pressure reducing valve a (8) and the pilot proportional pressure reducing valve b (9) to control the position of the closed center multi-way valve (7); the oil at the outlet of the variable pump (13) supplies oil to the oil inlet of the closed center multi-way valve (7) through the one-way valve (10), when the closed center multi-way valve (7) is in the middle position, the oil return port of the closed center multi-way valve (7) has no additional flow to return to the oil tank (18), so as to ensure the energy saving efficiency and response speed of the whole system, when the closed center multi-way valve (7) is in the left position, the rodless cavity of the lifting and lowering oil cylinder (3) is supplied with oil and the rod cavity returns oil, and the lifting action is completed; when the closed center multi-way valve (7) is in the right position, the rod cavity of the lifting and lowering oil cylinder (3) is supplied with oil and the rodless cavity returns oil, and the lowering action is completed; The variable pump (13) is electrically controlled, when the control handle (1) is actuated, the signal is transmitted to the controller (2), at the same time, the pressure and flow signals of the two cavities of the lifting and lowering oil cylinder (3) and the pressure and flow signals at the outlet of the variable pump (13) are transmitted to the controller (2) through the cable, the controller (2) transmits the control electric signal to the proportional pilot valve (15), and then controls the opening size of the proportional pilot valve (15); the oil provided by the oil supplement pump (16) enters the rodless cavity of the adjusting mechanism (14) through the proportional pilot valve (15), and the position of the hydraulic rod of the adjusting mechanism (14) can adjust the displacement of the variable pump (13); the opening size of the closed center multi-way valve (7) and the flow of the variable pump (13) are controlled by the controller (2) at the same time, the pressure and flow of the lifting and lowering oil cylinder (3) are adjusted, and the adaptive matching to the time-varying load is realized.

2. The electrically controlled positive flow drawworks hydraulic system for a truck-mounted drilling rig of claim 1, characterized in that: The overflow valve a (5), the overflow valve b (6) and the overflow valve c (17) are used to automatically determine whether the pressure of the lifting hydraulic system exceeds the preset pressure, wherein the overflow valve c (17) is used as a safety valve, the set pressure of the overflow valve c (17) is higher than that of the overflow valve a (5) and the overflow valve b (6), further ensuring that the whole lifting hydraulic system will not appear the phenomenon of high pressure, and the maximum pressure of the lifting hydraulic system is the set value of the overflow valve c (17); the set pressure of the overflow valve a (5) and the overflow valve b (6) is slightly smaller than that of the overflow valve c (17), so as to protect the lifting cylinder (3) from being damaged.

3. A method of operating the electrically controlled positive flow drawworks hydraulic system of claim 1, characterized by The steps are as follows: After the on-board drilling machine electric control positive flow lifting hydraulic system starts to work, the engine (11) is started, the engine (11) drives the variable pump (13) and the oil supplementing pump (16) to work through the connecting shaft (12), and oil is supplied to the closed center multi-way valve (7), the lifting cylinder (3) and the pilot proportional pressure reducing valve a (8), the pilot proportional pressure reducing valve b (9) and the proportional pilot valve (15) respectively; When the lifting cylinder (3) is lifted, the rodless cavity needs to take in oil and the rod cavity needs to return oil: the signal input by the control handle (1) is transmitted to the controller (2), the electric signal sent by the controller (2) controls the proportional pressure reducing valve (8) and the proportional pilot valve (15) at the same time, the closed center multi-way valve (7) works at the left position under the action of the proportional pressure reducing valve (8), the high-pressure oil pumped out by the variable pump (13) enters the rodless cavity of the lifting cylinder (3) through the closed center multi-way valve (7), and the oil in the rod cavity of the lifting cylinder (3) returns to the oil tank (18) through the oil return port of the closed center multi-way valve (7); When the lifting cylinder (3) is lowered, the rod cavity needs to take in oil and the rodless cavity needs to return oil: the signal input by the control handle (1) is transmitted to the controller (2), the electric signal sent by the controller (2) controls the proportional pressure reducing valve (9) and the proportional pilot valve (15) at the same time, the closed center multi-way valve (7) works at the right position under the action of the proportional pressure reducing valve (8), the high-pressure oil pumped out by the variable pump (13) enters the rod cavity of the lifting cylinder (3) through the closed center multi-way valve (7), and the oil in the rodless cavity of the lifting cylinder (3) returns to the oil tank (18) through the oil return port of the closed center multi-way valve (7); During the lifting process of the lifting cylinder (3), the controller (2) analyzes the signal input by the control handle (1), the pressure and flow signals in the rodless cavity and the rod cavity of the lifting cylinder (3) and the pressure and flow signals at the outlet of the variable pump (13), since the maximum pilot pressure value determines the flow of the system, at this time, the controller (2) adjusts the position of the hydraulic rod of the adjusting mechanism (14) to adjust the displacement of the variable pump (13); at the same time, the controller (2) calculates the opening size of the closed center multi-way valve (7) matched with the displacement of the variable pump (13), and the controller (2) adjusts the working position and opening size of the closed center multi-way valve (7) through the pilot proportional pressure reducing valve a (8) and the pilot proportional pressure reducing valve b (9). When the proportional pilot valve (15) works in the left position, the control oil enters the rodless cavity of the adjusting mechanism (14), and the hydraulic rod of the adjusting mechanism (14) adjusts the variable pump (13) to reduce the flow rate; When the proportional pilot valve (15) works in the right position, the rodless cavity of the adjusting mechanism (14) is connected to the oil tank (18), and the hydraulic rod of the adjusting mechanism (14) adjusts the variable pump (13) to increase the flow rate under the action of the built-in spring, thereby ensuring the matching degree of the system output flow rate and the required flow rate and improving the energy saving of the system.

4. A method for coordinated control of the pump and valve of the hydraulic system of the vehicle-mounted drilling rig of claim 1, characterized in that, The controller (2) includes a feedforward controller and a feedback controller. Since the purpose of the controller (2) is to match the flow rate of the variable pump (13) with the flow rate of the closed center multi-way valve (7) and to be proportional to the maximum pressure of the handle, and in order to reduce the pressure impact, the response speed of the closed center multi-way valve (7) should be as high as possible, therefore the variable pump (13) uses the feedback controller to ensure that the output flow rate of the variable pump (13) is consistent with the calculated value of the controller (2), and the closed center multi-way valve (7) uses a composite controller composed of a feedforward controller and a feedback controller, wherein the feedforward controller is used to improve the response speed of the closed center multi-way valve (7), and the feedback controller is used to ensure that the opening of the closed center multi-way valve (7) is consistent with the calculated value of the controller (2); The specific steps are as follows: The controller (2) calculates the speed r of the hoisting system of the vehicle-mounted drilling rig at this time by comparing the input signal of the control handle (1). a (t), encoder (4) feeds back the movement speed signal v of the hydraulic rod on the lifting cylinder (3). a With the set speed r a The difference between (t) and e is a (t), at this time e a (t) The corresponding output voltage value u is generated after calculation by the feedback controller. a1 (t) Adjust the output flow rate of the variable pump (13); Setting speed r of the lifting cylinder (3) a (t) a feedforward signal is generated through a feedforward controller, which is superimposed with a feedback signal generated through a feedback controller to generate a corresponding output voltage value u a2 (t), the output voltage value u a2 (t) adjusts the opening size of the closed-center multi-way valve (7); the output flow of the variable pump (13) matches the opening of the closed-center multi-way valve (7) to adjust the lifting cylinder (3).

5. The pump-valve cooperative control method according to claim 4, wherein The vehicle-mounted drilling machine electric control positive flow lifting hydraulic system is used to control the feeding of the vehicle-mounted drilling machine, the controller (2) used includes a feedforward controller and a feedback controller, a feedforward-feedback closed-loop control method is adopted, and the speed error signal of the vehicle-mounted drilling machine electric control positive flow lifting hydraulic system is obtained in advance; Wherein the feedback controller is proportional integral differential control PID, the feedforward controller is a combination of differential element and proportional element, the control parameters are respectively feedforward differential coefficient k v and feedforward proportional coefficient k f ; the feedback controller takes the speed error signal of the system as input, and gives the electric control positive flow pump unit an error repair amount after PID controller calculation to adjust the flow. The feedforward controller takes the set speed of the vehicle-mounted drilling machine electric control positive flow lifting hydraulic system as input, and after calculation, a feedforward advance is given to the displacement control of the main valve core of the closed center multi-way valve (7), so as to match the response time of the pump and valve, eliminate the overflow loss caused by the pressure impact in front of the valve, and achieve the purpose of improving the response speed of the system; Specifically: the target drilling speed r is set for the drilling machine controlled by the positive flow hydraulic system of the vehicle-mounted drilling machine a (t), the encoder (4) detects the actual speed v of the lifting cylinder (3) a , compares the difference with the input target drilling speed r a (t) to calculate the error speed signal e a (t), and processes the feedback controller to generate the feedback control signal u a1 (t); at the same time, the input target drilling speed r a (t) is processed by the feedforward controller to generate the feedforward control signal, which is added to the feedback control signal processed by the PID controller to obtain the superimposed control signal u a2 (t); finally, the feedback control signal u a1 (t) acts on the pilot control end of the positive flow pump to control the displacement of the positive flow pump, and the superimposed control signal u a2 (t) acts on the valve port opening of the positive flow valve feedback control signal u a1 The expression of (t) is as follows: ， Superimposed control signal u a2 (t) is given by the expression ， where: k p is a proportionality constant, e a (t) is the speed error, T i is an integral time constant, T d is a derivative time constant, k v is a feedforward derivative constant, k f is a feedforward proportionality constant.

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