CN115448165A

CN115448165A - Braking system and control method for lifting mechanism of crane

Info

Publication number: CN115448165A
Application number: CN202211062347.XA
Authority: CN
Inventors: 李朝; 涂从欢; 张晓光; 何畏
Original assignee: Shenzhen Sine Electric Co ltd
Current assignee: Shenzhen Sine Electric Co ltd
Priority date: 2022-08-31
Filing date: 2022-08-31
Publication date: 2022-12-09

Abstract

The embodiment of the invention provides a braking system and a control method for a lifting mechanism of a crane, wherein the system at least comprises the following components: the device comprises an encoder, a lifting mechanism motor, a brake, a speed reducer and a frequency converter, wherein the frequency converter is respectively connected with the encoder and the brake, and the lifting mechanism motor is connected with a heavy object through the speed reducer; the encoder is used for measuring the position and the speed of a motor of the lifting mechanism; the brake is used for controlling the rotation and stop of the motor of the lifting mechanism; the frequency converter is used for controlling the lifting mechanism motor to lift, lower or keep a heavy object to be fixed through the output three-phase voltage of the lead, only the failure of the brake is judged, and specific software processing logic is added during power failure, so that a protection mechanism can be added, the occurrence of major safety accidents is avoided, the cost is not increased, and one protection is added.

Description

Braking system and control method for lifting mechanism of crane

Technical Field

The invention relates to the technical field of automatic control, in particular to a braking system and a control method for a lifting mechanism of a crane.

Background

In order to reduce the danger, the crane lifting mechanism can automatically run if the lifted object is detected to fall downwards during the shutdown, the object is suspended in the air by output torque, and then the driver slowly puts the object on the ground to avoid accidents.

However, when the brake fails and a driver does not know that an object needs to be slowly placed downwards by using the operating rod, the sudden stop switch is slammed down due to panic and is powered off or the abnormal situation is powered off in a construction site, the frequency converter is not powered on, the object cannot be controlled by the motor to be stably in the air, and the object still falls, so that a major safety accident is caused.

Disclosure of Invention

In view of the above, embodiments of the present invention have been developed to provide a crane hoisting mechanism brake system and control method that overcome or at least partially address the above-mentioned problems.

In a first aspect, embodiments of the present invention provide a crane hoist braking system, the system comprising at least: the device comprises an encoder, a lifting mechanism motor, a brake, a speed reducer and a frequency converter, wherein the frequency converter is respectively connected with the encoder and the brake, and the lifting mechanism motor is connected with a heavy object through the speed reducer;

the encoder is used for measuring the position and the speed of a motor of the lifting mechanism;

the brake is used for controlling the rotation and stop of the lifting mechanism motor;

the frequency converter is used for outputting three-phase voltage through a lead to control the lifting mechanism motor to lift and lower or keep a heavy object still.

Optionally, the frequency converter is connected to an encoder for obtaining the position and speed of the motor of the lifting mechanism.

Optionally, the frequency converter is connected with the brake through a wire for controlling the brake and the release of the brake.

Optionally, the motor of the lifting mechanism is connected with the weight through a steel wire rope on an i-shaped wheel connected with the speed reducer, and is used for controlling the up-down movement and the stop of the weight.

Optionally, the system further includes a power module, the power module is connected to the frequency converter, and the power module is configured to provide power for the frequency converter.

In a second aspect, an embodiment of the present invention provides a crane hoisting mechanism brake control method, which is applied to the crane hoisting mechanism brake system described in the first aspect, and the method includes:

detecting a power supply signal input into the frequency converter and judging whether the power is cut off currently;

detecting a feedback signal of a motor encoder, and judging whether a brake fails at present according to the feedback signal of the motor encoder;

and if the power supply is powered off and the brake is determined to be invalid, controlling the heavy object to move according to the bus voltage of the frequency converter.

Optionally, if the power supply is powered off and it is determined that the brake fails, controlling the movement of the weight according to the bus voltage of the frequency converter includes:

when the heavy object descends, the motor of the lifting mechanism is in a power generation state, the gravitational potential energy of the heavy object is converted into electric energy to provide a power supply for the frequency converter until the heavy object is placed on the ground.

Optionally, if the power supply is powered off and it is determined that the brake fails, controlling the movement of the heavy object according to the bus voltage of the frequency converter, further includes:

the frequency converter obtains the rotating speed and the position of the motor through an encoder on the motor of the lifting mechanism;

in a shutdown state, the frequency converter monitors the position of a rotor of the lifting motor through an encoder;

and when the position of the rotor of the motor is greater than the first preset value N, sending a brake closing instruction again, running at zero speed and setting a brake failure mark.

Optionally, the detecting a power signal input to the frequency converter and determining whether the current power supply is off includes:

and if the time for maintaining the high level of the power supply signal input into the frequency converter is longer than a second preset value, determining that the power supply signal input into the frequency converter is in a power-off state.

if the power supply is powered off and the brake is determined to be invalid, acquiring a preset bus voltage and a current bus voltage;

acquiring a bus voltage error value;

and taking an inverse number from the bus voltage error value, performing PID (proportion integration differentiation) adjustment to obtain a PID adjustment value, and performing amplitude limiting on the PID adjustment value to obtain an actual operating frequency instruction.

The embodiment of the invention has the following advantages:

Drawings

FIG. 1 is a schematic structural diagram of a crane hoist braking system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a power down detection circuit of an embodiment of the present invention;

FIG. 3 is a block diagram of the frequency converter output frequency calculation when power loss and brake failure occur simultaneously in an embodiment of the present invention;

fig. 4 is a schematic flow chart of the frequency converter according to the embodiment of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Referring to fig. 1, there is shown a schematic structural view of a crane hoist braking system of the present invention, the system comprising at least: the device comprises an encoder, a lifting mechanism motor, a brake, a speed reducer and a frequency converter, wherein the frequency converter is respectively connected with the encoder and the brake, and the lifting mechanism motor is connected with a heavy object through the speed reducer;

the brake is used for controlling the rotation and stop of the motor of the lifting mechanism;

the frequency converter is used for outputting three-phase voltage through the lead to control the lifting mechanism motor to lift and lower or keep heavy objects still.

The frequency converter is connected with the encoder and used for acquiring the position and the speed of a motor of the lifting mechanism; the frequency converter is connected with the brake through a lead and used for controlling the brake and the release of the brake, and the motor of the lifting mechanism is connected with the heavy object through a steel wire rope on the spool connected with the speed reducer and used for controlling the up-down movement and the stop of the heavy object.

As shown in fig. 2 and fig. 3, the frequency converter outputs three-phase voltage through a lead to control the lifting mechanism motor to lift, lower or keep the heavy object still; the encoder is connected with a shaft of the lifting mechanism motor and is used for measuring the position and the speed of the lifting mechanism motor; the frequency converter is connected with the encoder and used for acquiring the position and the speed of a motor of the lifting mechanism; the frequency converter is connected with the brake through a lead and is used for controlling the brake and the release of the brake; the brake is connected with the lifting mechanism motor and is used for controlling the rotation and stop of the motor; the motor of the lifting mechanism is connected with the heavy object through a steel wire rope on an I-shaped wheel connected with the reduction box and is used for controlling the up-down movement and the stop of the heavy object.

Fig. 4 is a schematic flow chart of a frequency converter according to an embodiment of the present invention, and as shown in fig. 4, an embodiment of the present invention provides a method for controlling a brake of a lifting mechanism of a crane, which is applied to a braking system of the lifting mechanism of the crane, and the method includes:

detecting a feedback signal of a motor encoder, and judging whether the brake fails or not at present according to the feedback signal of the motor encoder;

Specifically, the technical scheme adopted by the invention is that whether the current power is cut off is judged by detecting the power supply input into the frequency converter, the feedback signal of the motor encoder is detected, and whether the brake fails is judged. When the two conditions are effective simultaneously, the heavy object is controlled to descend according to the bus voltage of the frequency converter, when the heavy object descends, the motor of the lifting mechanism is in a power generation state, the gravitational potential energy of the heavy object is converted into electric energy which can provide a power supply for the frequency converter until the heavy object is placed on the ground, the frequency converter loses the power generation source, and the output is stopped when the power consumption is exhausted.

According to the embodiment of the invention, only a specific software processing logic is added when the brake is judged to be invalid and the power is cut off, a protection mechanism can be added, so that the occurrence of major safety accidents is avoided, the cost is not increased, and one protection is added.

Optionally, if the power supply is powered off and it is determined that the brake fails, controlling the movement of the weight according to the bus voltage of the frequency converter comprises:

Optionally, if the power supply is powered off and it is determined that the brake fails, controlling the movement of the heavy object according to the bus voltage of the frequency converter, further comprising:

Optionally, detecting a power signal input to the frequency converter, and determining whether the current power supply is off includes:

obtaining a bus voltage error value;

and taking an inverse number for the bus voltage error value, performing PID (proportion integration differentiation) adjustment to obtain a PID adjustment value, performing amplitude limiting on the PID adjustment value, and obtaining an actual operating frequency instruction.

Specifically, the frequency converter obtains the rotating speed and the position of the motor through an encoder on the motor of the lifting mechanism, monitors the position of a rotor of the lifting motor through the encoder in a shutdown state, and sends a brake closing instruction again when the position of the rotor of the motor is larger than a set value N, and simultaneously outputs 0Hz to set a brake failure flag;

when the power of the frequency converter is started, the input power supply is always detected, and when the time for maintaining the high level of the level at the point A exceeds T, the input power supply is judged to be powered down through a common power supply power failure detection circuit in the figure; when power failure and brake failure occur simultaneously, the heavy object is placed downwards according to the frequency regulated by the current bus voltage of the frequency converter, when the output frequency of the frequency converter is defined as negative in the text, the heavy object is controlled to move downwards, a bus voltage Udc _ Ref to be controlled is set, the current bus voltage of the frequency converter is Udc, the bus voltage error is e, then the error is subjected to inverse number, PID regulation is performed, the PID regulation value is subjected to amplitude limiting, the limiting frequency F1 can be set through parameters, and the actual operating frequency is-F1 or more and F or less than 0. The PID controller calculates the control quantity by using proportion, integral and differential according to the error of the system to control.

The brake failure judgment pulse N is a settable value, the power failure judgment time T is a settable value, and the reference bus voltage is a settable value.

It should be noted that, for simplicity of description, the method embodiments are described as a series of acts or combination of acts, but those skilled in the art will recognize that the present invention is not limited by the illustrated order of acts, as some steps may occur in other orders or concurrently in accordance with the embodiments of the present invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no particular act is required to implement the invention.

It should be noted that the respective implementable modes in the present embodiment may be implemented individually, or may be implemented in combination in any combination without conflict, and the present application is not limited thereto.

For the apparatus embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and reference may be made to the partial description of the method embodiment for relevant points.

The embodiments in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, embodiments of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or electronic device that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or electronic device. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or electronic device that comprises the element.

Claims

1. A crane hoist braking system, characterized in that the system comprises at least: the device comprises an encoder, a lifting mechanism motor, a brake, a speed reducer and a frequency converter, wherein the frequency converter is respectively connected with the encoder and the brake, and the lifting mechanism motor is connected with a heavy object through the speed reducer;

2. The system of claim 1, wherein the frequency converter is coupled to the encoder for obtaining the position and speed of the hoist motor.

3. The system of claim 1, wherein the frequency converter is connected to the brake by a wire for controlling the brake application and release.

4. The system of claim 1, wherein the hoist motor is connected to the weight via a wire rope on a spool connected to the reducer for controlling the up and down movement and stopping of the weight.

5. The system of claim 1, further comprising a power module coupled to the frequency converter, the power module configured to provide power to the frequency converter.

6. A crane hoist brake control method applied to a crane hoist brake system according to any one of claims 1 to 5, the method comprising:

detecting a feedback signal of a motor encoder, and judging whether a brake fails or not at present according to the feedback signal of the motor encoder;

7. The method of claim 6, wherein controlling the movement of the weight according to the converter bus voltage if the power source is powered down and the brake is determined to be failed comprises:

8. The method of claim 6, wherein if the power source is powered down and the brake is determined to be failed, controlling the weight movement according to the converter bus voltage, further comprising:

in a shutdown state, a frequency converter monitors the position of a rotor of a lifting motor through an encoder;

9. The method of claim 6, wherein the detecting the power signal input to the frequency converter to determine whether the power is currently off comprises:

10. The method of claim 6, wherein controlling the movement of the weight according to the converter bus voltage if the power source is powered down and the brake is determined to be failed comprises:

obtaining a bus voltage error value;