The present disclosure relates to an oil pressure control system and control method thereof.
Oil pressure control systems are often used in power output units of mechanical equipment (such as machine tools) to provide power sources such as hydraulic turret and hydraulic chucks. The existing oil pressure control system will continuously operate and output at full power after being activated.
According to an embodiment of the present disclosure, an oil pressure control method, adapted for mechanical equipment, includes: providing a control device; obtaining, by the control device, a processing program from the mechanical equipment, wherein the processing program comprises a processing start code and a motor activation code of a motor; calculating, by the control device, an interval period between the processing start code and the motor activation code; determining, by the control device, whether the interval period is not shorter than a default period; setting, by the control device, the interval period as a default blank period in a motor operation timing sequence and setting, by the control device, a wake up interval in the default blank period according to the motor activation code when determining the interval period is not shorter than the default period; setting, by the control device, the interval period as a default low speed period in the motor operation timing sequence when determining the interval period is shorter than the default period; and controlling, by the control device, the motor according to the motor operation timing sequence; wherein an interval except for the wake up interval in the default blank period indicates the motor having a first rotational speed, and the default low speed period indicates the motor having a second rotational speed, wherein the first rotational speed is lower than the second rotational speed.
According to an embodiment of the present disclosure, an oil pressure control system, adapted for mechanical equipment, includes: a motor and a control device. The control device is connected to the mechanical equipment, and configured to perform: obtaining a processing program from the mechanical equipment, wherein the processing program comprises a processing start code and a motor activation code of a motor; calculating an interval period between the processing start code and the motor activation code; setting the interval period as a default blank period in a motor operation timing sequence and setting a wake up interval in the default blank period according to the motor activation code when determining the interval period is not shorter than a default period; setting the interval period as a default low speed period in the motor operation timing sequence when determining the interval period is shorter than the default period; and controlling the motor according to the motor operation timing sequence; wherein an interval except for the wake up interval in the default blank period indicates the motor having a first rotational speed, and the default low speed period indicates the motor having a second rotational speed, wherein the first rotational speed is lower than the second rotational speed.
The detailed features and advantages of the present invention are described in detail below in the embodiments. Numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. According to the description, claims and the drawings disclosed in the specification, one skilled in the art may easily understand the concepts and features of the present invention. The following examples further illustrate the aspects of the present invention in detail, but are not meant to limit the scope of the present invention.
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The control device 10 is connected to the mechanical equipment and the motor 11, the motor 11 is connected to the pressure accumulator 12. The control device 10 may include one or more processors, wherein the processor is, for example, a central processing unit, a microcontroller, a programmable logic controller or any other processor with signal processing functions. The motor 11 may be a servomotor or a variable-frequency motor. The pressure accumulator 12 may be configured to store pressure and controlled to release pressure. Also, one or more oil paths of the mechanical equipment and the pressure accumulator 12 may each include a pressure sensor connected to the control device 10 so that the control device 10 may monitor the pressure of the oil paths of the mechanical equipment and the pressure of the pressure accumulator 12.
The control device 10 is configured to read a processing program from the mechanical equipment, and schedule an operation timing sequence of the motor 11 in advance according to the processing program to obtain a motor operation timing sequence, and control an operation of the motor 11 according to the motor operation timing sequence. The processing program may include processing codes (for example, processing codes of processing tools and activation code of the motor etc.) recorded in the form of M code. The processing program includes an action sequence, frequency and operation of each processing tool (not shown in the figure), wherein the processing tool may include a hydraulic turret and a chuck of the processing machine.
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The oil tank 21 is configured to store hydraulic oil. The motor 22 is configured to drive the pump 23 to deliver the hydraulic oil in the oil tank 21. The non-return valve 24 is configured to prevent the hydraulic oil from flowing back to the pump 23. The overflow valve 25 is configured to drain the excessive hydraulic oil back to the oil tank 21 when the output pressure of the motor 22 is higher than a set pressure. The pressure sensor 27 may be configured to sense pressure output to the load 28, wherein the load 28 may be any machinery or hydraulic device that requires hydraulic pressure to perform work, such as a hydraulic cylinder. The control device 20 may control the motor 22 according to the pressure sensor 27. The control device 20 may also control the opening or closing of the solenoid valve 29 to control the hydraulic oil to flow from the load 28 back to the oil tank 21 when the solenoid valve 29 is opened.
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In step S101, the control device 10 is provided, and the control device 10 may be initialized. The initialization may be, for example, building a connection relationship between the control device 10 and the motor 11.
In step S103, the control device 10 obtains the processing program from the mechanical equipment. The processing program includes the processing start code and the motor activation code of the motor 11. The processing start code may be a first processing code in the processing program, meaning the first operation performed during the entire processing. The motor activation code may be a processing code indicating when the motor 11 should start operating after the processing starts.
In step S105, the control device 10 calculates the interval period between the processing start code and the motor activation code. In other words, the interval period may be a duration from a time point when the processing starts to a time point when the motor 11 starts operating.
In step S107, the control device 10 determines whether the interval period is not shorter than the default period, wherein the default period is, for example, 15 minutes, but the present disclosure is not limited thereto. When the interval period is not shorter than the default period, it means that the motor 11 corresponds to a long interval operation (i.e. the motor 11 accelerates and decelerates less frequently), and when the interval period is shorter than the default period, it means that the motor 11 corresponds to a short interval operation (i.e. the motor 11 accelerates and decelerates more frequently).
When the interval period is not shorter than the default period, in step S109, the control device 10 sets the interval period as the default blank period in the motor operation timing sequence, and sets the wake up interval in the default blank period according to a time point where the motor 11 starts operating indicated by the motor activation code, wherein an ending time point of the wake up interval is the same as an ending time point of the default blank period. On the contrary, when the interval period is shorter than the default period, in step S111, the control device 10 sets the interval period as the default low speed period in the motor operation timing sequence.
Further, an interval except for the wake up interval in the default blank period indicates the motor having a first rotational speed, and the default low speed period indicates the motor having a second rotational speed, wherein the first rotational speed is lower than the second rotational speed. For example, the first rotational speed is zero, and the second rotational speed is a default minimum rotational speed. In the default blank period and the default low speed period, pressure required for processing may be provided by the pressure accumulator 12.
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After setting the motor operation timing sequence, in step S113, the control device 10 controls the operation of the motor 11 according to the motor operation timing sequence. For example, step S113 may include controlling a rotational speed of the motor 11 according to the target pressure when determining that a pressure of the pressure accumulator 12 is lower than the default pressure during the default blank period or the default low speed period, wherein the control device 10 may control the rotational speed of the motor 11 by performing a proportional-integral-derivative (PID) control by using the target pressure. Take
In other words, when the processing starts, if the motor operation timing sequence indicates the default blank period, then the motor 11 operates in the first rotational speed; and if the motor operation timing sequence indicates the default low speed period, then the motor 11 operates in the second rotational speed. Further, when arriving at the wake up interval, the control device 10 starts to wake up the motor 11, and the control device 10 may control the rotational speed of the motor 11 according to the target pressure during the wake up interval when determining that the pressure of the pressure accumulator 12 is lower than the default pressure. Therefore, the motor 11 may start operating at the starting time point of the default operating period.
Accordingly, by setting the motor operation timing sequence to pre-activate the motor before the motor needs to start operating, instantaneous changes in the power load caused by frequent acceleration and deceleration of the motor may be avoided, thereby reducing energy consumption.
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In step S203, the control device 10 determines whether the default oil pressure usage frequency included in the processing program is higher than the default frequency to set the operation of the motor 11 in the default operating period according to the determination result. The default oil pressure usage frequency may include one or more of the frequency of replacement of processing tools, the frequency of clamping and unclamping tools, and the frequency of using braking unit, etc., the present disclosure is not limited thereto.
When the control device 10 determines that the default oil pressure usage frequency is higher than the default frequency, it means that the processing may require frequent processing by the motor 11. Therefore, the control device 10 performs step S205 to set the motor 11 to perform the first operation during the default operating period. The first operation may include activating the motor 11 when the pressure of the pressure accumulator 12 is lower than the default pressure. Said activating the motor 11 may include controlling the motor 11 according to the target pressure. Further, said activating the motor 11 may be using the target pressure as a reference value, and performing PID calculation according to a pressure difference between the target pressure and the pressure of the motor 11 (i.e. load pressure). Further, when the pressure of the pressure accumulator 12 is lower than the default pressure, the first operation may include replenishing the pressure of the pressure accumulator 12 when the pressure of the pressure accumulator 12 is lower than the default pressure.
In addition, in other embodiments, the first operation may include controlling the motor 11 to output working pressure during the default operating period P2 and controlling the pressure accumulator 12 to replenish the insufficient working pressure. In other words, during the first operation, the control device 10 may control the motor 11 to output power and cooperate with the pressure output by the pressure accumulator 12, thereby reducing frequent acceleration and deceleration of the motor 11.
On the contrary, when the control device 10 determines that the default oil pressure usage frequency is not higher than the default frequency, it means that the processing may not require frequent processing by the motor 11. Therefore, the control device 10 may set the motor 11 to perform the second operation during the default operating period P2, wherein the second operation is different from the first operation. For example, the second operation may include controlling the motor 11 to operate in the first rotational speed or the second rotational speed.
By setting the operation of the motor according to the default oil pressure usage frequency, the need for frequent acceleration and deceleration of the motor due to frequent switching between hibernation (sleep) mode and activation mode may be avoided, thereby reducing the energy consumption of the motor.
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In step S303, the control device 10 may obtain the pressure of the pressure accumulator 12 from the pressure sensor of the pressure accumulator 12 to determine whether the pressure of the pressure accumulator 12 is lower than the default pressure. When the pressure of the pressure accumulator 12 is not lower than the default pressure, the first operation may include performing step S303 again to monitor the pressure accumulation state of the pressure accumulator 12 in real time during actual processing operations.
When the pressure of the pressure accumulator 12 is lower than the default pressure, in step S305, the control device 10 may control the motor 11 according to the target pressure. As described above, the control device 10 may perform PID control on the rotational speed of the motor 11 according to the load pressure and the target pressure. Since the pressure of the pressure accumulator 12 is lower than the default pressure, the pressure accumulator 12 may be in a suspension state. Therefore, in step S307, the motor 11 may replenish the pressure of the pressure accumulator 12.
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In step S403, the control device 10 determines whether the mechanical equipment is in the leakage state, wherein the leakage state may indicate that there is oil leakage in the mechanical equipment. Further, when a sensed pressure of a pressure sensor at the oil path of the mechanical equipment is lower than a default value, the control device 10 may determine that there is oil leakage in the mechanical equipment accordingly.
When the control device 10 determines that the mechanical equipment is in the leakage state, the control device 10 performs step S405 to control the pressure of the motor 11 as the default minimum load pressure, so that the motor 11 operates in the default minimum rotational speed. In addition, the control device 10 may perform PID calculation on the pressure difference between the current pressure (i.e. the load pressure) of the motor 11 and the default minimum load pressure to control the motor 11.
On the contrary, when the control device 10 determines that the mechanical equipment is not in the leakage state, the control device 10 performs step S407 to lower the current pressure of the motor 11 to zero, so that the motor 11 may enter the hibernation mode. In other words, the operation of the motor 11 completely stops. Accordingly, the power consumption of the motor may be reduced, thereby avoiding unnecessary waste.
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In the steps shown in
During the stage of processing according to the motor operation timing sequence, the contents of steps S519, S521 and S523 are the same as steps S303, S305 and S307 of
In addition, when the determination result of step S519 is “no”, the control device 10 may perform step S525 to continue the processing according to the motor operation timing sequence. In other words, when the determination result of step S519 is “no”, the control device 10 may perform step S519 again to monitor the pressure accumulation state of the pressure accumulator 12 in real time.
It should be noted that the above uses the oil pressure control system 1 of
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In view of the above, the oil pressure control method and system according to one or more embodiments of the present disclosure, by setting the motor operation timing sequence to pre-activate the motor before the motor needs to start operating, instantaneous changes in the electric load caused by frequent acceleration and deceleration of the motor may be avoided. Further, by controlling the motor and the pressure accumulator to have respective pressure output means for when the default oil pressure usage frequency is higher than the default frequency, the need for frequent acceleration and deceleration of the motor due to frequent switching between hibernation (sleep) mode and activation mode may be avoided, thereby reducing the energy consumption of the motor. In addition, by setting the motor operation timing sequence as controlling the motor according to the default minimum load pressure when the mechanical equipment is not in the leakage state, the power consumption of the motor may be reduced, thereby avoiding unnecessary waste.