阅读说明：本技术 一种基于pid控制的压力机平衡系统及平衡方法 (Pressure machine balance system and balance method based on PID control ) 是由 马中涛 姜长升 魏凤凯 陈启升 郭呈祥 刘学顺 于 2020-05-26 设计创作，主要内容包括：本发明公开了一种基于PID控制的压力机平衡系统及平衡方法,属于压力机技术领域,包括压力机机架,压力机机架上设有可沿第一方向滑动的滑块,滑块连接有驱动滑块滑动的电机,压力机机架上还设有气缸,气缸与滑块连接,气缸上设有电控调压阀,电机的供电线路上设有电流测量组件,电流测量组件连接有控制器,控制器与电控调压阀连接；本发明利用了电机中电流波动偏差与压力机平衡之间的正相关性,依据测量电机中电流的波动偏差量,通过PID算法运算后,计算出对压力机的气缸的输出力的调节量,可以有效的保证滑块在下行时的平衡,避开了原先在气缸内部恶劣环境内部署传感器的情形,操作简单,成本低廉,有效的保障了平衡系统的稳定运行。(The invention discloses a press machine balance system and a press machine balance method based on PID control, belonging to the technical field of press machines, and comprising a press machine frame, wherein a slide block capable of sliding along a first direction is arranged on the press machine frame, the slide block is connected with a motor for driving the slide block to slide, an air cylinder is also arranged on the press machine frame, the air cylinder is connected with the slide block, an electric control pressure regulating valve is arranged on the air cylinder, a current measuring assembly is arranged on a power supply line of the motor, the current measuring assembly is connected with a controller, and the controller is connected with; the invention utilizes the positive correlation between the current fluctuation deviation in the motor and the balance of the press, calculates the adjustment quantity of the output force of the cylinder of the press after the PID algorithm operation according to the fluctuation deviation quantity of the current in the measured motor, can effectively ensure the balance of the slide block during the descending, avoids the original situation that a sensor is deployed in the severe environment in the cylinder, has simple operation and low cost, and effectively ensures the stable operation of a balance system.)

1. The utility model provides a press balance system based on PID control, its characterized in that, includes the press frame, be equipped with the gliding slider of first direction of following in the press frame, the slider is connected with the drive the gliding motor of slider, still be equipped with the cylinder in the press frame, the cylinder with the slider is connected, be equipped with automatically controlled air-vent valve on the cylinder, be equipped with current measurement subassembly on the power supply line of motor, current measurement subassembly is connected with the controller, the controller with automatically controlled air-vent valve is connected.

2. The PID control-based press balancing system according to claim 1, wherein the current measuring assembly is an electronic ammeter.

3. The PID control-based press balancing system according to claim 1, wherein the controller is a PID controller.

4. The press balancing system based on the PID control as claimed in claim 1, wherein the cylinder comprises a cylinder body and a piston arranged in the cylinder body, part of the inner surface of the cylinder body and the piston form an air cavity, the piston is connected with a piston rod, the other end of the piston rod is connected with the slider, the cylinder is provided with an air hole communicated with the air cavity, and the air hole is connected with an air source.

5. The PID control-based press balancing system according to claim 4, wherein the electrically controlled pressure regulating valve is provided on the air hole or the air source or a pipeline between the air hole and the air source.

6. The PID control-based press balancing system according to claim 1, wherein a transmission assembly is arranged between the motor and the slide block for connection.

7. A press balancing method based on PID control is characterized by comprising the following steps:

step 1: setting a measuring period and a proper current range;

step 2: the motor drives the sliding block to move, the current measuring component measures current information on a power supply circuit of the motor in real time and sends the current information in one measuring period to the controller;

and step 3: the controller judges whether all the current information in one measurement period is in the proper current range according to the preset proper current range; if the current information is all in the proper current range, the controller does not work, otherwise, the next step is carried out;

and 4, step 4: calculating the current information and the median of the proper current range to obtain a current error;

and 5: carrying out differential calculation on the current error to obtain a current error differential value;

step 6: performing integral calculation on the current error to obtain a current error integral value;

and 7: obtaining an air pressure regulating quantity after PID operation according to the current error, the current error differential value and the current error integral value;

and 8: and (3) the controller adjusts the electric control pressure regulating valve according to the air pressure adjusting quantity, and repeats the step (2) to the step (7) until the current information is in the proper current range.

Technical Field

The invention relates to the technical field of presses, in particular to a press balancing system and a press balancing method based on PID control.

Background

The press machine (including punch press and hydraulic press) is generally a device which drives a working mechanism by a motor through a transmission mechanism and applies technological force to a workpiece, and has the characteristics of wide application, high production efficiency and the like. The press machines process the metal into parts by applying a strong pressure to the metal blank to plastically deform and fracture the metal. When the press machine works, a motor drives a large belt pulley (usually used as a flywheel) through a triangle belt, and a crank-slider mechanism is driven through a gear pair and a clutch, so that a slider and a male die move downwards in a straight line. After the forging and pressing work of the press is finished, the sliding block moves upwards, the clutch is automatically disengaged, and meanwhile, the automatic device on the crankshaft is switched on, so that the sliding block stops near a top dead center.

The balance system of the press machine generally comprises a cylinder, a piston rod is arranged on a piston of the cylinder, the piston rod is connected with a sliding block, the cylinder is fixed on a machine body, and compressed gas is introduced into a gas cavity of the cylinder. When the sliding block moves upwards, compressed gas enters an air cavity of the air cylinder; and when the sliding block moves downwards, compressed gas is discharged from the air cavity of the air cylinder. Compressed gas in the cylinder jacks up the piston to support the sliding block, so that the weight of the transverse sliding block and the upper die is leveled, and overspeed during the lower stroke of the sliding block is avoided. The balance system of the press has the following three main functions: firstly, when the sliding block travels downwards, the falling speed of the self weight is too high, so that parts (such as gears) in a transmission system are reversely stressed to cause impact and noise; secondly, eliminating a gap between the connecting rod and the sliding block and reducing the impact of the stressed part; thirdly, accidents caused by the falling of the sliding block due to the failure of the brake, the damage of the crankshaft or the breakage of the connecting rod are prevented; in addition, the balancing system also facilitates rapid recovery of flywheel energy.

The balance system of the existing press machine mainly changes the balance force by adjusting the air inlet pressure of an air cylinder, thereby balancing the weight of a sliding block and an upper die. The balance system is mainly divided into two types: 1. theoretical value control method: the mounting and debugging workers adjust the pressure regulating valve of the air cylinder according to the numerical value theoretically measured and calculated by technicians; the method has the defects that due to the influence of calculation deviation and the self friction force of the cylinder, deviation is easily formed when the method is adjusted according to a theoretical value, and unbalance loading is caused; 2. sensor-based regulation system: the method is characterized in that a sensor is arranged on a mechanical structure part in the cylinder, and the sensor responds to a pressure regulating valve according to a value fed back by the sensor, so that the balance of the cylinder is realized, and the method has the following defects: due to the influence of the pressure environment in the cylinder, the sensitivity of the sensor and the operation control reliability, deviation is easy to form, and unbalance loading is caused; the sensor is high in price and complex in maintenance, belongs to a quick-wear part, is poor in applicability, and increases production cost.

Disclosure of Invention

For the problems in the prior art, the pressure machine balance system and the balance method based on the PID control provided by the invention utilize the positive correlation between the current fluctuation deviation in the motor and the pressure machine balance, adjust the output force of the air cylinder of the pressure machine according to the fluctuation deviation quantity of the current in the motor, effectively ensure the balance of the slide block during descending, avoid the situation that a sensor is originally deployed in the severe environment inside the air cylinder, have simple operation and low cost, and effectively ensure the stable operation of the balance system.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides a press machine balance system based on PID control, which comprises a press machine frame, wherein a sliding block capable of sliding along a first direction is arranged on the press machine frame, the sliding block is connected with a motor for driving the sliding block to slide, an air cylinder is further arranged on the press machine frame, the air cylinder is connected with the sliding block, an electric control pressure regulating valve is arranged on the air cylinder, a current measuring assembly is arranged on a power supply line of the motor, the current measuring assembly is connected with a controller, and the controller is connected with the electric control pressure regulating valve.

As a preferred technical solution, the current measuring component is an electronic ammeter.

As a preferred technical solution, the controller is a PID controller.

As a preferred technical scheme, the air cylinder comprises a cylinder body and a piston arranged in the cylinder body, an air cavity is formed by part of the inner surface of the cylinder body and the piston, the piston is connected with a piston rod, the other end of the piston rod is connected with the sliding block, an air hole communicated with the air cavity is formed in the air cylinder, and the air hole is connected with an air source.

As a preferable technical solution, the electrically controlled pressure regulating valve is arranged on the air hole or the air source or a pipeline between the air hole and the air source.

As a preferred technical scheme, a transmission assembly is arranged between the motor and the sliding block to be connected.

In a second aspect, the invention provides a press balancing method based on PID control, which comprises the following steps:

step 1: setting a measuring period and a proper current range;

step 2: the motor drives the sliding block to move, the current measuring component measures current information on a power supply circuit of the motor in real time and sends the current information in one measuring period to the controller;

and step 3: the controller judges whether all the current information in one measurement period is in the proper current range according to the preset proper current range; if the current information is all in the proper current range, the controller does not work, otherwise, the next step is carried out;

and 4, step 4: calculating the current information and the median of the proper current range to obtain a current error;

and 5: carrying out differential calculation on the current error to obtain a current error differential value;

step 6: performing integral calculation on the current error to obtain a current error integral value;

and 7: obtaining an air pressure regulating quantity after PID operation according to the current error, the current error differential value and the current error integral value;

and 8: and (3) the controller adjusts the electric control pressure regulating valve according to the air pressure adjusting quantity, and repeats the step (2) to the step (7) until the current information is in the proper current range.

The beneficial effects of the invention are as follows:

the invention utilizes the positive correlation between the current fluctuation deviation in the motor and the balance of the press, calculates the adjustment quantity of the output force of the cylinder of the press after the PID algorithm operation according to the fluctuation deviation quantity of the current in the measured motor, can effectively ensure the balance of the slide block during the descending, avoids the original situation that a sensor is deployed in the severe environment in the cylinder, has simple operation and low cost, and effectively ensures the stable operation of a balance system.

Drawings

FIG. 1 is a schematic structural diagram of a press balancing system based on PID control according to the invention;

FIG. 2 is a functional block diagram of a press balancing system based on PID control.

In the figure: 1-a press frame, 2-a slide block, 3-a motor and 4-a cylinder.

Detailed Description

In order to facilitate understanding for those skilled in the art, the present invention will be further described with reference to the accompanying drawings.

Referring to fig. 1 and 2, in a first aspect, the present invention provides a press balancing system based on PID control, including a press frame 1, a slide block 2 capable of sliding along a first direction is disposed on the press frame 1, the slide block 2 is connected to a motor 3 for driving the slide block 2 to slide, the press frame 1 is further provided with a cylinder 4, the cylinder 4 is connected to the slide block 2, the cylinder 4 is provided with an electrically controlled pressure regulating valve, a power supply line of the motor 3 is provided with a current measuring assembly, the current measuring assembly is connected to a controller, and the controller is connected to the electrically controlled pressure regulating valve.

It should be noted that the motor 3 generally drives the large belt pulley (generally also used as a flywheel) through a triangle belt, and drives the crank slider 2 mechanism through a gear pair and a clutch, so as to move the slider 2, and the transmission component for driving the slider 2 to slide by the motor 3 is common knowledge of the press machine, and is not described herein again; the sliding block 2 is usually fixed at the bottom of a guide seat, the guide seat is connected with the press machine frame 1 in a sliding manner, and the motor 3 drives the sliding block 2 to move in a manner of driving the guide seat to move; the first direction is generally a vertical direction; the change amplitude of the air pressure in the air cavity of the air cylinder 4 can be adjusted by adjusting the opening and closing degree of the electric control pressure regulating valve, so that the change amplitude of the output force of the air cylinder 4 is adjusted.

On the basis of the above embodiment, the current measuring component is set as an electronic ammeter, and the controller is set as a PID controller.

On the basis of the embodiment, the air cylinder 4 comprises a cylinder body and a piston arranged in the cylinder body, an air cavity is formed by the inner surface of part of the cylinder body and the piston, the piston is connected with a piston rod, the other end of the piston rod is connected with the sliding block 2, an air hole communicated with the air cavity is formed in the air cylinder 4, and the air hole is connected with an air source; the air pressure of an air cavity in the air cylinder 4 can be adjusted through an air source, so that the output force of the piston rod to the sliding block 2 is adjusted; furthermore, the electric control pressure regulating valve is arranged on the air hole or the air source or a pipeline between the air hole and the air source, and the change range of the air pressure in the air cavity can be adjusted by adjusting the opening and closing degree of the electric control pressure regulating valve, so that the change range of the output force of the air cylinder 4 to the sliding block 2 is changed, and the stress of the sliding block 2 is kept balanced.

On the basis of the above embodiment, a transmission assembly is arranged between the motor 3 and the sliding block 2 for connection, and the transmission assembly may include a V-belt, a large belt pulley, a gear pair and a clutch.

In a second aspect, the invention provides a press balancing method based on PID control, which comprises the following steps:

step 1: setting a measuring period and a proper current range; the current measuring component measures current information on a power supply circuit of the motor 3 at least three times in a measuring period, the proper current range refers to the current value range of the motor 3 of the press machine in a balanced state when the press machine is at a determined pressing pressure value, and the current value range can be obtained through theoretical value measurement or actual experimental measurement;

step 2: the motor 3 drives the sliding block 2 to move, the current measuring component measures current information on a power supply line of the motor 3 in real time and sends the current information in a measuring period to the controller; specifically, the motor 3 drives the sliding block 2 to move through the transmission assembly;

and step 3: the controller judges whether all current information in one measurement period is in the proper current range according to the preset proper current range; if the current information is all in the proper current range, the controller does not work, otherwise, the next step is carried out; the current information is all in the proper current range, which indicates that the output force of the motor 3 is balanced and stable, i.e. the press is in a balanced state.

And 4, step 4: calculating the current information and the median value of the proper current range to obtain a current error;

and 5: carrying out differential calculation on the current error to obtain a differential value of the current error;

step 6: carrying out integral calculation on the current error to obtain a current error integral value;

and 7: obtaining air pressure regulating quantity after PID operation according to the current error, the current error differential value and the current error integral value; the proportional coefficient in the PID calculation can be calculated according to a theoretical value or an actual experiment, and of course, in actual use, the proportional coefficient can be appropriately adjusted according to an actual situation;

and 8: and (3) the controller adjusts the electric control pressure regulating valve according to the air pressure adjusting quantity, and repeats the step (2) to the step (7) until the current information is in the proper current range.

It should be noted that, on the premise that the power supply voltage is constant, the current value on the power supply line of the motor 3 is in direct proportion to the power of the motor 3 to the slider 2, when the press is in a balanced state, the motor 3 stably applies work to the slider 2, the current on the power supply line is stable, when the press is in an unbalanced state, the work of the motor 3 to the moving slider 2 is certainly influenced, so that the deviation or fluctuation of the current value on the power supply line is caused, that is, the positive correlation between the current fluctuation deviation in the motor 3 and the balance of the press is caused, when the slider 2 moves downwards, if the current value on the power supply line is larger than the normal current value, the motor 3 applies work to the slider 2 is larger, the lifting force of the cylinder 4 to the slider 2 needs to be increased by adjusting the electrically controlled pressure regulating valve; and vice versa.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.