Hydraulic tension machine control method and control system

Abstract

The invention relates to a control method and a control system for a hydraulic tensioner, the control method comprises the following steps of: regulating and controlling the processes of brake starting, constant tension spreading, reverse traction and delivery and on-load stopping of the hydraulic tensioner, and the control system can realize the control method; by adopting the control method and the control system of the hydraulic tension machine, the hydraulic tension machine can be stably loaded and spread at constant tension, and can be in a completely static pressure maintaining state when the hydraulic tension machine is stopped with load; the problems that in the prior art, a tensioner is insufficient in control stability, safety risks exist when braking is started, and uncontrolled wriggling exists when on-load stopping is conducted are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic tension machine control, and in particular to a hydraulic tension machine control method and control system. Background Art

[0002] Hydraulic tension machines are widely used in overhead wire tensioning construction of power transmission lines. Their main working conditions include traction / wire delivery and tension conditions. The traction / wire delivery condition is usually used for construction preparation and wire crimping processes. The main hydraulic pump and the main hydraulic motor working oil port are in a directly connected state. The main pump output flow drives the hydraulic motor to realize active traction or delivery of the tension wheel. The speed of the hydraulic motor is adjusted by adjusting the displacement of the main hydraulic pump to complete the pre-winding and force of the wire on the tension wheel. The tension condition is the main working condition of the tension machine. It provides continuously adjustable tension / resistance for the deployment of overhead wires and realizes the smooth deployment of overhead wires. It is a typical passive working condition. The generation of tension is achieved by adjusting the inlet and outlet pressure difference of the main motor. Among them, the pressure on the oil inlet side of the motor is controlled by the back pressure valve to keep constant. By steplessly and continuously adjusting the pressure of the pilot relief valve connected in series with the motor pressure oil side, the motor outlet pressure can be adjusted, thereby changing the inlet and outlet pressure difference of the motor, adjusting the driving torque under the motor pump working condition, which corresponds to the driving force of the tension wheel, and realizing stepless and continuous adjustment of tension. At the same time, the rotation speed of the tension wheel is adaptive to the speed of the traction machine pulling the wire, and cooperates with the traction machine to realize the tension wire stringing process with controllable speed and tension. The hydraulic tension machine based on the above principle does not require additional mechanical brakes when working, but from a safety perspective, a brake is configured on the reducer connected to the main motor, which can be combined with the brake when the tension machine stops working for a long time under load.

[0003] The main shortcomings of the hydraulic tension machine in the prior art are as follows:

[0004] 1. During the conductor deployment process, the motor outlet adjustment pressure will fluctuate due to factors such as traction speed and pipeline flow resistance, which will reduce the tension adjustment accuracy, affect the stability of the tension deployment operation and the stability of the tension, and cause a large deviation in the conductor deployment relaxation;

[0005] 2. When the mechanical brake is turned on under load, the brake is directly converted from the braking state to the opening state, and the load is quickly transferred to the hydraulic motor, which will cause the hydraulic motor outlet pressure to rise sharply, thereby causing a severe impact on the hydraulic tensioner, resulting in damage to the hydraulic system components, the tension wheel mechanical transmission mechanism and the wires wound on the tension wheel. This situation is particularly obvious when the wire tension is large;

[0006] 3. When the tension machine is in the brake shutdown state, the tension setting value is adjusted due to human error, or the external load changes significantly due to other reasons. In this case, the brake is opened and the hydraulic system is in a low-pressure state. There will be a risk of line running due to insufficient tension, which seriously affects construction safety.

[0007] 4. During the conductor deployment process, when the traction machine stops the traction operation, the tension machine will be in a loaded stop state. Without the brake, due to the inevitable leakage of components such as the overflow valve in the hydraulic system, the tension wheel cannot remain completely still, but is in a slow creeping state due to the internal leakage of the system, which interferes with the wire deployment work, especially when the conductor tension is large.

[0008] In summary, the transmission and control system of the tension machine in the prior art has problems such as insufficient tension control stability, safety risks when the brake is turned on, and uncontrolled creep when the load stops, all of which cause troubles and risks to the stability and safety of construction operations. Summary of the invention

[0009] To this end, the technical problem to be solved by the present invention is to overcome the deficiencies in the transmission and control systems of the tension machine in the prior art, and to provide a hydraulic tension machine control method and control system to regulate the processes of braking opening, constant tension release and load stopping of the hydraulic tension machine, so as to ensure that the hydraulic tension machine can be loaded stably, constant tension release can be released, and can be in a completely static pressure maintaining state when the load stops.

[0010] In order to solve the above technical problems, the present invention provides a hydraulic tension machine control method, comprising the following steps:

[0011] Start the tension machine:

[0012] A1. Switch the brake switch from the brake position to the open position. The controller controls the main hydraulic pump to preload and continuously compares the main pressure value PA with the memory pressure value PC stored in the non-volatile memory during the last braking. When PA≥PC, the controller controls the brake solenoid valve to be energized and the brake is opened.

[0013] A2. After the brake is turned on, the controller obtains the current main pressure value PA through the main pressure sensor, calculates the current tension value Td, and adjusts the target tension value Tm stored in the non-volatile memory from Tmax to Td. At this time, the tension machine is in a loaded static state, and the tension release preparation work is completed;

[0014] Tension release:

[0015] B1. The target tension value Tm can be continuously adjusted through the tension adjustment potentiometer. The current value of Tm is stored in the non-volatile memory of the controller. The controller will continuously collect the current main pressure value PA, calculate the current tension value Td, and compare it with the target tension value Tm. Tm is used as the target value and Td as the feedback value. Through the PID adjustment closed-loop control mode, the deviation between Tm and Td is converted into a dynamic adjustment of the control current of the main overflow valve, so that the deviation between Tm and Td approaches 0;

[0016] B2. After the tension release preparation work is completed or the traction machine used in conjunction with the tension release operation stops traction operation, the tension machine will be in a loaded stop state. When the enabling conditions are met, the tension machine is refilled with oil to keep it in a loaded stationary state until the traction operation is resumed;

[0017] Towing and delivery operations:

[0018] C. Switching between reverse pulling and sending out is realized through the control handle. When the control handle is pulled from the middle position to the pulling position, the controller controls the hydraulic pump to output pressure oil with a variable current value Ip in proportion to the pulling angle, and drives the motor to rotate forward, driving the tension wheel to perform the pulling operation; when the control handle is pulled from the middle position to the wire sending position, the controller controls the hydraulic pump to output pressure oil with a variable current value It in proportion to the pulling angle, and drives the motor to rotate in the reverse direction, driving the tension wheel to perform the active wire sending operation;

[0019] Stop a job:

[0020] D1. Switch the brake switch from the open position to the brake position. The controller will write the currently collected main pressure value PA into the non-volatile memory and record it as the memory pressure value PC. At the same time, the brake solenoid valve is controlled to lose power. At this time, the brake is applied.

[0021] D2. After the braking is completed, the controller changes the target tension value Tm to the maximum preset tension value Tmax of the tension machine.

[0022] In one embodiment of the present invention, when the tension machine is started, the position of the tension machine brake switch is detected, and the start command can be executed only when the tension machine brake switch is in the braking position.

[0023] In one embodiment of the present invention, when starting the tension machine, the control current value Ip of the main hydraulic pump is adjusted. Ip starts from the set initial value Imin and gradually increases in a calibrated time-related increasing manner. At the same time, this current is output to the displacement control proportional solenoid valve of the main hydraulic pump. At this time, the main hydraulic pump will output hydraulic oil corresponding to the Ip value, causing the main pressure value PA to continuously increase until PA≥PC. Then, the controller controls the brake solenoid valve to be energized, the brake is opened, and at the same time, the Ip value is restored to 0. At this time, the main hydraulic pump will stop outputting hydraulic oil, completing the pre-pressurization process.

[0024] In one embodiment of the present invention, when starting the tension machine, the brake is opened by means of pre-pressurization. A certain time delay t1 is set. After the brake is opened and delayed by t1, the controller obtains the main pressure value PA corresponding to the current load through the main pressure sensor, automatically calculates the current target tension value Tm from PA, and the controller automatically adjusts the target tension setting value from Tmax to Tm to complete the preparation for the tension operation.

[0025] In one embodiment of the present invention, in step B2, the enabling conditions include:

[0026] The controller continuously collects the rotational speed signal n of the hydraulic motor through the rotational speed sensor, satisfying n < n1, where: n1 is a set constant, and the set value of n1 should be greater than the creeping speed of the tension wheel;

[0027] The controller collects the main pressure value PA, satisfying PA > PD, where: PD is a set constant, and the set value of PD should be greater than the low-pressure side pressure of the hydraulic motor;

[0028] The brake electromagnet is in the energized state, that is, the brake is in the open state;

[0029] When the above three conditions are simultaneously satisfied and maintained for more than the time delay t2, the oil replenishment function of the tension machine is started.

[0030] In one embodiment of the present invention, in step B2, when replenishing oil to the tension machine, the current tension value Td is calculated and compared with the target tension value Tm. Taking Tm as the target value and Td as the feedback value, through PID regulation or other feasible closed-loop control methods, the deviation between Tm and Td is used to dynamically adjust the control current I1 of the main pump, so that the deviation between Tm and Td approaches 0. In this case, the leakage of the hydraulic system will be dynamically compensated by the output pressure oil of the main hydraulic pump, so that the tension machine can maintain a stationary state under load and will not continuously creep outward.

[0031] In one embodiment of the present invention, in step B2, after the tension machine resumes normal deployment operation, as the speed of the tension wheel increases, the enabling condition will not be met, the tension machine oil replenishment function will stop, and additional power loss and resulting system heating will not continue to be generated.

[0032] In one embodiment of the present invention, in step C, the maximum traction force can be set by the traction force adjustment potentiometer, and the real-time traction force value can be displayed in real time on the display. When overload occurs, that is, the real-time traction force value exceeds the set maximum traction force value, the traction operation will be automatically stopped and maintained, and the traction operation can only be resumed when the control handle is reset.

[0033] In one embodiment of the present invention, when the operation is stopped, the engine speed information and the hydraulic system pressure information are continuously collected. If the engine speed and the system pressure are both lower than the minimum threshold, the controller will control the brake electromagnet to lose power.

[0034] The present invention also discloses a control system for a hydraulic tension machine, which can realize the above control method, including:

[0035] A controller capable of executing the above control method;

[0036] A hydraulic pump, wherein the hydraulic pump is an electric proportional variable displacement pump, and the hydraulic pump is integrated with a bidirectional proportional solenoid valve, and the opening of the solenoid valve is controlled by proportional current input to achieve different displacement adjustments of the hydraulic pump;

[0037] A hydraulic motor is connected to the drum via a speed reducer and a gear pair to drive the drum to rotate;

[0038] An engine is connected to the hydraulic pump, and drives the hydraulic pump to rotate, converting the work of the hydraulic pump into pressure energy of the hydraulic system, thereby providing energy supply for the hydraulic system;

[0039] The brake is used to transfer the external load on the drum to the mechanical structure of the equipment. When the brake is reliably applied, the hydraulic pump will be in a low-pressure standby state;

[0040] Solenoid valve, which is a two-position three-way solenoid reversing valve, is used to control the on-off of the brake oil circuit, and then control the opening and closing of the brake. After the brake is turned on, the external load on the drum is borne and driven by the hydraulic motor to achieve the traction or wire feeding operation of the traction machine;

[0041] A first pressure sensor, which is installed at a working oil port of the hydraulic pump and is used to measure the real-time pressure of the hydraulic pump;

[0042] A second pressure sensor, which is installed at the working oil port of the hydraulic motor and is used to measure the oil port pressure PA on the high-pressure side of the hydraulic motor. The pressure measured by the pressure sensor is positively correlated with the external load currently borne by the drum;

[0043] A rotation speed sensor, which is installed on the hydraulic motor and connected to the controller through a cable to measure the real-time rotation speed of the hydraulic motor;

[0044] The handle, as an input element of the traction operation control signal, is connected to the controller through a cable. The handle provides an input of a voltage proportional signal and two direction signals. The direction signal is a switch signal used to control operation, stop and operation direction.

[0045] The throttle potentiometer is connected to the controller through a cable and is used to set the engine speed;

[0046] The traction force preset potentiometer is connected to the controller through a cable and is used to set the maximum traction force of the equipment.

[0047] The tension adjustment potentiometer is connected to the controller through a cable and is used to set the target tension value of the equipment.

[0048] The above technical solution of the present invention has the following advantages compared with the prior art:

[0049] The invention provides a control method for a hydraulic tension machine, which can meet various functions required by the hydraulic tension machine during construction, such as tension release, reverse pulling and active wire feeding.

[0050] The control method of the present invention can effectively solve the impact problem caused by opening the brake under load. When the brake switch is switched, the system will automatically complete the smooth preloading process. After completing the loading process, it will automatically set the target tension value according to the actual load on the current tension wheel, which effectively simplifies the operation and completely avoids the risk of line deviation due to misoperation.

[0051] The control method of the present invention solves the creeping wire slipping caused by leakage of the hydraulic system under the condition of zero speed / low speed and heavy load of the tension machine through the oil replenishment function, and can ensure that the tension machine is in a completely static state under this condition, eliminating the interference of this condition on the construction operation;

[0052] In addition, by setting the enabling conditions, the oil replenishment function will not cause additional system heating during high-speed deployment, and will not affect the daily maintenance and commissioning of the tension machine;

[0053] In the tension release process of the present invention, the constant tension function is used through a closed-loop control method, which effectively solves the impact of factors such as traction speed on the stability of the tension machine and the tension stability during the tension release process.

[0054] During the traction and wire feeding process of the present invention, the controller controls the hydraulic pump to output pressure oil with a changing current value in proportion to the pulling angle, thereby avoiding construction risks caused by overload in the case of reverse traction and risks caused by diesel engine stalling in the case of reverse traction.

[0055] During the shutdown operation of the present invention, after the braking is completed, the controller changes the value of the target tension value Tm to the maximum preset tension value Tmax of the tension machine, which can avoid the risk of starting the diesel engine under load due to misoperation. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0057] Figure 1 It is a flow chart of the steps of the startup process of the hydraulic tension machine of the present invention;

[0058] Figure 2 It is a flow chart of steps when the hydraulic tension machine of the present invention is in tension working condition;

[0059] Figure 3 It is a flow chart of the steps of the traction and wire feeding working conditions of the hydraulic tension machine of the present invention;

[0060] Figure 4 It is a flow chart of the steps of stopping the hydraulic tension machine of the present invention. DETAILED DESCRIPTION

[0061] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0062] Example 1

[0063] The present invention discloses a control method for a hydraulic tension machine, which can control the start-up of the hydraulic tension machine, tension release during construction, reverse pulling and active wire feeding, and the stopping process, so as to ensure that the hydraulic tension machine can be stably loaded, constantly release tension, and can be in a completely static pressure-maintaining state when stopped with load. The specific operating steps of each working condition are described below.

[0064] In order to better illustrate the control method of the present invention, the control principle of the tension machine is briefly described first:

[0065] 1. Based on the working principle of the hydraulic tension machine, the tension T of the tension machine is generated by the pressure difference △P between the inlet and outlet of the hydraulic motor, which can be expressed by the formula: T = K△P; where K is the proportional coefficient, which is related to the motor displacement, mechanical efficiency and dimension. For a fixed-displacement motor with a certain specification and model, K can be regarded as a constant; therefore, by adjusting the value of △P, the T value can be proportionally adjusted.

[0066] Since △P=PA-PB, PA is the pressure on the high-pressure oil port side of the hydraulic motor, called the main pressure, and PB is the pressure on the low-pressure side of the hydraulic motor. Both PA and PB values ​​can be collected by pressure sensors installed at corresponding positions. In addition, PB is controlled by the back-pressure relief valve installed on the low-pressure side of the motor, so it is a fixed value, and the PA value is controlled by the proportional pilot relief valve installed on the high-pressure side of the motor. When the current output by the controller to the pilot relief valve solenoid changes, the PA value changes proportionally. In summary, in fact, the PA value corresponds to the actual tension value on the current wheel, and tension adjustment can be achieved by controlling PA.

[0067] 2. As we know from the above, in the control of the tension machine, the tension value ratio is equivalent to the main pressure value ratio. In actual operation, the target tension value Tm can be adjusted through the tension adjustment potentiometer. The voltage change generated by the rotation of the potentiometer can continuously change the target value Tm. Every time the controller collects the change of the target value Tm, it executes to store the new target value Tm in the non-volatile memory. The adjustable range of Tm is limited to between Tmin and Tmax. Tmin and Tmax are both constant values, where Tmin is the initial tension value, which is related to the initial value of the rotation of the tension machine of this specification and can be regarded as a constant. The corresponding pressure value is PB, and Tmax is the maximum allowable tension of this model of tension machine. The corresponding pressure value can be calculated by formula, recorded as Pmax.

[0068] Therefore, according to the proportional relationship, when the main pressure value PA collected by the controller can be calculated by the following formula to obtain the current tension wheel tension T, that is:

[0069]

[0070] 3. This tension machine system adopts an electric proportional bidirectional variable hydraulic pump. The proportional solenoid valve integrated on the hydraulic pump is used to control the flow direction and flow of the pressure oil of the hydraulic pump. Correspondingly, the two electromagnet control currents on the proportional valve are defined as I p and It respectively. When I p is output, the corresponding main pump outputs flow to the high-pressure side of the motor. When It is output, the corresponding main pump outputs flow to the low-pressure side of the motor.

[0071] Combined with the actual use of the hydraulic tension machine, this control method mainly includes the following contents.

[0072] Reference Figure 1As shown, the steps of starting the tension machine include:

[0073] Turn on the power supply of the tension machine. At this time, the tension machine control system is energized and the engine can be started by the start key / start button. When the start command is issued, the controller will determine the position of the tension machine brake switch (two-position switch). Only when the brake switch is in the "brake" position, the controller executes the engine start command and controls the corresponding intermediate relay coil to be energized, thereby starting the hydraulic motor to be energized and completing the engine start.

[0074] Switch the brake switch from the "brake" position to the "open" position, and the controller will collect the rising edge signal (0→1) of the corresponding input pin of the brake switch. At this time, the controller continuously compares the main pressure value PA with the main pressure value PC stored in the non-volatile memory during the last braking, until PA≥PC, the controller controls the brake solenoid valve to be energized, the brake is opened, and the main hydraulic pump control current Ip is adjusted at the same time. Ip starts from the set initial value Imin and increases with time according to the incremental method set by the control software. At the same time, the current is output to the displacement control proportional solenoid valve of the main hydraulic pump. At this time, the main hydraulic pump will output hydraulic oil corresponding to the Ip value, so that the main pressure PA continues to increase until the brake is opened (PA≥PC), and the Ip value is restored to 0. At this time, the main hydraulic pump will stop outputting hydraulic oil and complete the pre-pressurization process.

[0075] After the brake is turned on, a certain time delay t1 is set to ensure that the brake is turned on stably. In the specific implementation, t1 can be set to be less than 1s. The controller obtains the current main pressure PA through the main pressure sensor, calculates the current tension value Td, and adjusts the target tension value Tm from Tmax to Td. At this time, the tension machine is in a loaded static state, and the tension release preparation work is completed.

[0076] The starting method of the present invention can effectively solve the impact problem caused by opening the brake under load. When the brake switch is switched, the system will automatically complete the smooth preloading process. After completing the loading process, it will automatically set the target tension value according to the actual load on the current tension wheel, which effectively simplifies the operation and completely avoids the risk of line deviation due to misoperation.

[0077] Reference Figure 2 As shown in the figure, the control process of tension release is:

[0078] During tension stringing, the working condition switch should be set to the "tension" condition. The operator can continuously adjust the target tension value Tm through the tension adjustment potentiometer. The controller will continuously collect the current main pressure PA, calculate the current tension value Td, compare it with the target tension value Tm, take Tm as the target value and Td as the feedback value, and through PID adjustment or other feasible closed-loop control methods, convert the deviation between Tm and Td into a dynamic adjustment of the control current of the main relief valve, so that the deviation between Tm and Td approaches 0, thereby ensuring that the actual tension Td on the wheel is not affected by factors such as traction speed or flow resistance, realizing constant tension stringing, and well solving the possible impact on the stability of the tension machine and tension stability during tension stringing due to factors such as traction speed.

[0079] When the preparation work for tension stringing is completed or after the traction machine used in coordination with it stops traction operation during tension stringing operation, the tension machine will be in a load-bearing stop state, manifested as the brake being in the open state, and the wire or rope wound on the tension wheel being in a state of a certain tension. At this time, due to the inevitable leakage of components such as the relief valve, the main pressure PA will decrease, and the tension wheel cannot be completely kept stationary, manifested as the tension wheel slowly creeping outwards under the action of the wire tension;

[0080] To solve this problem, when the preparation work for tension stringing is completed or after the traction machine used in coordination with it stops traction operation during tension stringing operation, the tension machine will be in a load-bearing stop state, and the tension machine will be refueled.

[0081] Specifically, to determine whether to refuel the tension machine, certain enabling conditions need to be set. In this embodiment, when the following three conditions are met simultaneously, the tension machine refueling function will be started:

[0082] First, the controller continuously collects the speed signal n through the speed sensor installed on the reducer or the main motor, and satisfies n < n1 (n1 is a constant, which can be calibrated according to requirements, and the calibrated n1 value should be greater than the creeping speed of the tension wheel, and at this time it represents that the tension machine is slipping the wire);

[0083] Second, the controller collects PA, and satisfies PA > PD (PD is a constant, which can be calibrated according to requirements, and the calibrated PD value should be greater than the PB value, that is, the low-pressure side pressure of the hydraulic motor), and at this time it represents that the hydraulic motor is in the working state;

[0084] Third, the brake electromagnet is in the energized state, that is, the brake is in the open state.

[0085] When these three judgment conditions are met simultaneously and maintained for more than the time delay t2 (t2 is calibrated according to actual requirements, generally set to about 3 seconds), this is used as the enabling condition to start the tension machine refueling function. The specific refueling process is as follows:

[0086] The current tension value Td is calculated and compared with the target tension value Tm. Tm is used as the target value and Td as the feedback value. Through PID adjustment or other feasible closed-loop control methods, the deviation between Tm and Td is used to dynamically adjust the main pump control current I1, so that the deviation between Tm and Td approaches 0. In this case, the leakage of the hydraulic system will be dynamically supplemented by the pressure oil output by the main hydraulic pump, so that the tension machine can remain stationary under load and will not continue to creep outward.

[0087] When the tension machine resumes normal operation, as the speed of the tension wheel increases, the enabling condition will not be met, and the tension machine oil replenishment function will stop, so that there will be no additional power loss and corresponding heat due to unnecessary oil replenishment. In addition, the existence of the second condition can avoid interference with the daily tension machine debugging in the non-operating state.

[0088] The control method of the present invention solves the creeping wire slipping caused by leakage of the hydraulic system under the condition of zero speed / low speed and heavy load of the tension machine through the oil replenishment function, and can ensure that the tension machine is in a completely static state under this condition, eliminating the interference of this condition on the construction operation;

[0089] Moreover, by setting the enabling conditions, the oil replenishment function will not cause additional system heating during high-speed deployment, and will not affect the daily care, maintenance and commissioning of the tension machine.

[0090] Reference Figure 3 As shown in the figure, the control process of traction and delivery operation is as follows:

[0091] C. Switching between reverse traction and delivery is achieved through the control handle. When the control handle is pulled from the middle position to the traction position, in proportion to the pulling angle, the controller controls the hydraulic pump to output pressure oil with a variable current value Ip, drives the motor to rotate forward, and drives the tension wheel to perform traction operations. When the control handle is pulled from the middle position to the wire feeding position, in proportion to the pulling angle, the controller controls the hydraulic pump to output pressure oil with a variable current value It, drives the motor to rotate in the reverse direction, and drives the tension wheel to perform active wire feeding operations.

[0092] Specifically, the maximum traction force can be set through the traction force adjustment potentiometer, and the real-time traction force value can be displayed in real time through the display. When overload occurs, that is, the real-time traction force value exceeds the set maximum traction force value, the traction operation will be automatically stopped, which can avoid construction risks caused by overload in the case of reverse traction and risks caused by diesel engine shutdown in the case of reverse traction.

[0093] Reference Figure 4 As shown in the figure, the control process of stopping the job is:

[0094] When the deployment operation needs to be stopped for a long time, the brake switch is switched from the "on" position to the "brake" position, and the controller will collect the falling edge signal (1→0) of the corresponding input pin of the brake switch. At this time, the controller will write the currently collected main pressure value PA into the non-volatile memory, recorded as PC. At the same time, the brake solenoid valve is controlled to lose power, and the brake is applied. After the braking is completed, the controller changes the target tension value Tm to the maximum preset tension value Tmax of the tension machine to prevent the tension setting value from being adjusted due to human error, or due to other reasons, the external load has changed significantly. In this case, if the brake is turned on, there will be a risk of running the line due to insufficient tension, which seriously affects the construction safety.

[0095] Specifically, after stopping the operation, the system will continue to collect engine speed information and hydraulic system pressure information. If the engine speed and system pressure are both lower than the minimum threshold (the engine speed threshold is generally set to 200r / min, and the system pressure threshold is generally set to 10bar), the delay will not exceed 3 seconds. Regardless of the position of the brake switch, the control system will control the brake electromagnet to lose power to ensure that the diesel engine is not turned off due to unexpected reasons, resulting in possible construction risks.

[0096] Example 2

[0097] On the basis of the above embodiment 1, in order to implement the above method, the present invention further discloses a control system of a hydraulic tension machine, comprising:

[0098] A controller capable of executing the above control method;

[0099] A hydraulic pump, wherein the hydraulic pump is an electric proportional variable displacement pump, and the hydraulic pump is integrated with a bidirectional proportional solenoid valve, and the opening of the solenoid valve is controlled by proportional current input to achieve different displacement adjustments of the hydraulic pump;

[0100] A hydraulic motor is connected to the drum via a speed reducer and a gear pair to drive the drum to rotate;

[0101] An engine is connected to the hydraulic pump, and drives the hydraulic pump to rotate, converting the work of the hydraulic pump into pressure energy of the hydraulic system, thereby providing energy supply for the hydraulic system;

[0102] The brake is used to transfer the external load on the drum to the mechanical structure of the equipment. When the brake is reliably applied, the hydraulic pump will be in a low-pressure standby state;

[0103] Solenoid valve, which is a two-position three-way solenoid reversing valve, is used to control the on-off of the brake oil circuit, and then control the opening and closing of the brake. After the brake is turned on, the external load on the drum is borne and driven by the hydraulic motor to achieve the traction or wire feeding operation of the traction machine;

[0104] A first pressure sensor, which is installed at a working oil port of the hydraulic pump and is used to measure the real-time pressure of the hydraulic pump;

[0105] A second pressure sensor, which is installed at the working oil port of the hydraulic motor and is used to measure the oil port pressure PA on the high-pressure side of the hydraulic motor. The pressure measured by the pressure sensor is positively correlated with the external load currently borne by the drum;

[0106] A rotation speed sensor, which is installed on the hydraulic motor and connected to the controller through a cable to measure the real-time rotation speed of the hydraulic motor;

[0107] The handle, as an input element of the traction operation control signal, is connected to the controller through a cable. The handle provides an input of a voltage proportional signal and two direction signals. The direction signal is a switch signal used to control operation, stop and operation direction.

[0108] The throttle potentiometer is connected to the controller through a cable and is used to set the engine speed;

[0109] The traction force preset potentiometer is connected to the controller through a cable and is used to set the maximum traction force of the equipment.

[0110] The traction force preset potentiometer is connected to the controller through a cable and is used to set the maximum traction force of the equipment. The potentiometer should be non-positioning and can produce cyclic voltage changes when rotated. The controller converts the collected changes into an increase or decrease in the target tension value, and when the target tension value changes, the new set value will be written into the non-volatile memory in the controller in real time, and will not be affected by the power on and off of the electrical system.

[0111] By executing the control method of Example 1 through the control system of the hydraulic tension machine of this embodiment, the startup of the hydraulic tension machine, the tension release during construction, the reverse pulling and active wire feeding, and the stopping process can be controlled, so as to ensure that the hydraulic tension machine can be loaded stably, the tension is released constantly, and it can be in a completely static pressure-maintaining state when it stops with load.

[0112] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A hydraulic tension machine control method, characterized in that: The following steps are involved: Start the tension machine: A1. Switch the brake switch from the brake position to the open position. The controller controls the main hydraulic pump to preload and continuously compares the main pressure value PA with the memory pressure value PC stored in the non-volatile memory during the last braking. When PA≥PC, the controller controls the brake solenoid valve to be energized and the brake is opened. A2. After the brake is turned on, the controller obtains the current main pressure value PA through the main pressure sensor, calculates the current tension value Td, and adjusts the target tension value Tm stored in the non-volatile memory from Tmax to Td. At this time, the tension machine is in a loaded static state, and the tension release preparation work is completed; Tension release: B1. The target tension value Tm can be continuously adjusted through the tension adjustment potentiometer. The current value of Tm is stored in the non-volatile memory of the controller. The controller will continuously collect the current main pressure value PA, calculate the current tension value Td, and compare it with the target tension value Tm. Tm is used as the target value and Td as the feedback value. Through the PID closed-loop control method, the deviation between Tm and Td is converted into a dynamic adjustment of the control current of the main overflow valve, so that the deviation between Tm and Td approaches 0; B2. After the tension release preparation work is completed or the traction machine used in conjunction with the tension release operation stops traction operation, the tension machine will be in a loaded stop state. When the enabling conditions are met, the tension machine is refilled with oil to keep it in a loaded stationary state until the traction operation is resumed; Towing and delivery operations: C. Switching between reverse pulling and sending out is realized through the control handle. When the control handle is pulled from the middle position to the pulling position, the controller controls the hydraulic pump to output pressure oil with a variable current value Ip in proportion to the pulling angle, and drives the motor to rotate forward, driving the tension wheel to perform the pulling operation; when the control handle is pulled from the middle position to the wire sending position, the controller controls the hydraulic pump to output pressure oil with a variable current value It in proportion to the pulling angle, and drives the motor to rotate in the reverse direction, driving the tension wheel to perform the active wire sending operation; Stop a job: D1. Switch the brake switch from the open position to the brake position. The controller will write the currently collected main pressure value PA into the non-volatile memory and record it as the memory pressure value PC. At the same time, the brake solenoid valve is controlled to lose power. At this time, the brake is applied. D2. After the braking is completed, the controller changes the target tension value Tm to the maximum preset tension value Tmax of the tension machine.

2. The hydraulic tension machine control method according to claim 1, characterized in that: When starting the tension machine, detect the position of the tension machine brake switch. When the tension machine brake switch is in the braking position, the start command can be executed.

3. The hydraulic tension machine control method according to claim 1, characterized in that: When starting the tension machine, adjust the main hydraulic pump control current value Ip. Ip starts from the set initial value Imin and gradually increases in a calibrable time-related incremental manner. At the same time, the current is output to the displacement control proportional solenoid valve of the main hydraulic pump. At this time, the main hydraulic pump will output hydraulic oil corresponding to the Ip value, so that the main pressure value PA continues to increase until PA ≥ PC. The controller controls the brake solenoid valve to be energized, the brake opens, and the Ip value is restored to 0. At this time, the main hydraulic pump will stop outputting hydraulic oil and complete the pre-pressurization process.

4. The hydraulic tension machine control method according to claim 1, characterized in that: When starting the tension machine, the brake is opened by means of pre-pressure, and a certain time delay t1 is set. After the brake is opened and delayed by t1, the controller obtains the main pressure value PA corresponding to the current load through the main pressure sensor, automatically calculates the current target tension value Tm through PA, and the controller automatically adjusts the target tension setting value from Tmax to Tm to complete the preparation for the tension operation.

5. The hydraulic tension machine control method according to claim 1, characterized in that: In step B2, the enabling conditions include: The controller continuously collects the rotational speed signal n of the hydraulic motor through the rotational speed sensor, satisfying n < n1, where: n1 is a set constant, and the set value of n1 should be greater than the creeping speed of the tension wheel; The controller collects the main pressure value PA, satisfying PA > PD, where: PD is a set constant, and the set value of PD should be greater than the low-pressure side pressure of the hydraulic motor; The brake electromagnet is in the energized state, that is, the brake is in the open state; When the above three conditions are simultaneously satisfied and maintained for more than the time delay t2, the oil replenishment function of the tension machine is started.

6. The hydraulic tension machine control method according to claim 1, characterized in that: In step B2, when replenishing oil to the tension machine, the current tension value Td is calculated and compared with the target tension value Tm. Taking Tm as the target value and Td as the feedback value, through PID regulation or other feasible closed-loop control methods, the deviation between Tm and Td acts on the dynamic regulation of the control current I1 of the main pump, so that the deviation between Tm and Td approaches 0. In this case, the leakage of the hydraulic system will be dynamically compensated by the pressure oil output by the main hydraulic pump, so that the tension machine can maintain a stationary state under load and will not continuously creep outward.

7. The hydraulic tension machine control method according to claim 1, characterized in that: In step B2, when the tension machine resumes normal paying-off operation, as the rotational speed of the tension wheel increases, the enabling conditions will not be met, and the oil replenishment function of the tension machine will stop, and no additional power loss and the resulting system heating will be continuously generated.

8. The hydraulic tension machine control method according to claim 1, characterized in that: In step C, the maximum traction force can be set through the traction force adjustment potentiometer, and the real-time traction force value can be displayed in real time through the display. When overload occurs, that is, when the real-time traction force value exceeds the set maximum traction force value, the traction operation will be automatically stopped and maintained, and the traction operation can only be resumed after the control handle is reset.

9. The hydraulic tension machine control method according to claim 1, characterized in that: When stopping the operation, continuously collect the rotational speed information of the engine and the pressure information of the hydraulic system. If both the engine speed and the system pressure are lower than the minimum threshold, the controller will control the brake electromagnet to lose power.

10. A control system for a hydraulic tension machine, capable of implementing the control method of claims 1 to 9, characterized in that: Including: A controller capable of executing the above control method; A hydraulic pump, the hydraulic pump is an electro-hydraulic proportional variable pump, and the hydraulic pump is integrated with a bidirectional proportional solenoid valve, and the opening degree of the solenoid valve is controlled by the proportional current input to achieve different displacement adjustments of the hydraulic pump; A hydraulic motor, which is connected to the drum through a speed reducer and a gear pair to drive the drum to rotate; An engine, which is connected to the hydraulic pump, and converts its work into hydraulic system pressure energy by driving the hydraulic pump to rotate to provide energy supply for the hydraulic system; A brake, which is used to transfer the external load on the drum to the equipment mechanical structure. When the brake brakes reliably, the hydraulic pump will be in the low-pressure standby state; Solenoid valve, which is a two-position three-way solenoid reversing valve, is used to control the on-off of the brake oil circuit, and then control the opening and closing of the brake. After the brake is turned on, the external load on the drum is borne and driven by the hydraulic motor to achieve the traction or wire feeding operation of the traction machine; A first pressure sensor, which is installed at a working oil port of the hydraulic pump and is used to measure the real-time pressure of the hydraulic pump; A second pressure sensor, which is installed at the working oil port of the hydraulic motor and is used to measure the oil port pressure PA on the high-pressure side of the hydraulic motor. The pressure measured by the pressure sensor is positively correlated with the external load currently borne by the drum; A rotation speed sensor, which is installed on the hydraulic motor and connected to the controller through a cable to measure the real-time rotation speed of the hydraulic motor; The handle, as an input element of the traction operation control signal, is connected to the controller through a cable. The handle provides an input of a voltage proportional signal and two direction signals. The direction signal is a switch signal used to control operation, stop and operation direction. The throttle potentiometer is connected to the controller through a cable and is used to set the engine speed; The traction force preset potentiometer is connected to the controller through a cable and is used to set the maximum traction force of the equipment; The tension adjustment potentiometer is connected to the controller through a cable and is used to set the target tension value of the equipment.

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