A method and device for protecting a band brake from failure

Abstract

The application discloses a kind of brake band brake failure protection method and device, can when brake band brake is in failure state, start open loop zero servo control mode, in open loop zero servo control mode, determine the motor starting frequency matched with the current falling speed of lifting load, control motor starts at motor starting frequency, to control lifting load starts to descend from falling speed by motor to lifting load by applying upward direction tension, after motor starts, the operating frequency of motor is adjusted from motor starting frequency to preset frequency of lowering, to control lifting load to be lowered to ground at smaller speed corresponding to frequency of lowering.The application can start open loop zero servo control mode when brake band brake fails without action anti-falling device, safely lower lifting load to ground in the case where mechanical impact suffered by lifting mechanism is effectively reduced and braking comfort is improved, improve the work safety of lifting mechanism.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control, in particular to a brake failure protection method and device for a brake. BACKGROUND

[0002] A construction hoist can be a mechanical device used for lifting people and goods in construction sites, high-rise buildings and other places. With the improvement of industrial automation control technology, the control technology of construction hoists is also constantly improving.

[0003] Currently, the prior art can use a fall protector to ensure the safety of the construction hoist. Specifically, when the construction hoist is running to the target floor, a closing instruction can be output to the brake, and under normal circumstances when the brake is not failed, the brake can be closed and tightly hold the cage after receiving the closing instruction, so that the cage can be stably suspended in the air. If the brake cannot tightly hold the cage due to brake damage or insufficient brake torque, the cage will fall, and at this time the fall protector will start to act and forcibly lock the gear to prevent the cage from continuing to fall.

[0004] However, when the brake fails, the prior art cannot effectively protect the construction hoist. SUMMARY

[0005] In view of the above problems, the present application provides a brake failure protection method and device for overcoming the above problems or at least partially solving the above problems, and the technical solution is as follows:

[0006] A brake failure protection method, comprising:

[0007] When the brake is in a failure state, starting an open-loop zero servo control mode;

[0008] In the open-loop zero servo control mode: determining a motor start frequency matched with a current falling speed of a lifting load; controlling the motor to start at the motor start frequency to control the lifting load to start descending from the falling speed by the motor applying an upward pulling force to the lifting load; after the motor starts at the motor start frequency, adjusting a running frequency of the motor from the motor start frequency to a preset lowering frequency to control the lifting load to descend to the ground at a target speed corresponding to the lowering frequency.

[0009] Optionally, when the brake is in a failure state, starting an open-loop zero servo control mode, comprising:

[0010] When the brake is in a failure state and the falling speed of the lifting load is less than a preset speed threshold, starting the open-loop zero servo control mode.

[0011] The method further comprises:

[0012] When the brake is in the failure state and the falling speed of the lifting load is not less than the speed threshold, starting the fall arrestor to brake the lifting load.

[0013] Optionally, the control of the motor to start at the motor starting frequency to apply the upward pulling force to the lifting load to control the lifting load to start to fall from the falling speed comprises:

[0014] The control of the motor to start at the preset input current and the motor starting frequency to apply the upward pulling force to the lifting load to control the lifting load to start to fall from the falling speed in the case of improving the torque output capability of the motor.

[0015] Optionally, before the starting of the open-loop zero servo control mode when the brake is in the failure state, the method further comprises:

[0016] After the closing signal is sent to the brake, the pulse count value sent by the encoder to measure the gear rotation turns is continuously monitored;

[0017] When the change value of the pulse count value is greater than a preset first pulse count change threshold, it is determined that the brake is in the failure state, the change value of the pulse count value being a difference between a currently monitored pulse count value and an initial value, the initial value being the pulse count value monitored for the first time after the closing signal is sent to the brake.

[0018] Optionally, after the starting of the open-loop zero servo control mode, the method further comprises:

[0019] Within a first preset time length, the pulse count value sent by the encoder is continuously monitored, and when a change value of the pulse count value within a second preset time length is less than a preset second pulse count change threshold, it is determined that the encoder malfunctions and that the brake is actually in a non-failure state;

[0020] When it is determined that the brake is in the actual non-failure state, the open-loop zero servo control mode is exited.

[0021] A brake failure protection device, comprising a first starting unit, a first determining unit, a control unit and an adjusting unit, wherein:

[0022] The first starting unit is configured to perform: starting an open-loop zero servo control mode when the brake is in a failure state;

[0023] the first determining unit is configured to determine a motor start frequency matching a current falling speed of the hoisting load in the open-loop zero servo control mode;

[0024] the control unit is configured to control the motor to start at the motor start frequency to control the hoisting load to start descending from the falling speed by the motor applying an upward pulling force to the hoisting load;

[0025] the adjusting unit is configured to adjust the operating frequency of the motor from the motor start frequency to a preset lowering frequency after the motor starts at the motor start frequency to control the hoisting load to descend to the ground at a target speed corresponding to the lowering frequency.

[0026] Optionally, the first starting unit is configured to:

[0027] start the open-loop zero servo control mode when the band brake is in the failure state and the falling speed of the hoisting load is less than a preset speed threshold.

[0028] The device further comprises a second starting unit, and the second starting unit is configured to:

[0029] start the band brake to brake the hoisting load when the band brake is in the failure state and the falling speed of the hoisting load is not less than the speed threshold.

[0030] Optionally, the control unit is configured to:

[0031] control the motor to start at a preset input current and the motor start frequency to control the hoisting load to start descending from the falling speed by the motor applying an upward pulling force to the hoisting load in a case of improving the torque output capability of the motor.

[0032] Optionally, the device further comprises a first monitoring unit and a second determining unit, and wherein:

[0033] the first monitoring unit is configured to monitor a pulse count value for measuring the number of gear rotations sent by the encoder continuously after sending the closing signal to the band brake before starting the open-loop zero servo control mode when the band brake is in the failure state.

[0034] The second determining unit is configured to determine that the brake band is in the failure state when a variation value of the pulse count value is greater than a preset first pulse count variation threshold, the variation value of the pulse count value being a difference between a current monitored pulse count value and an initial value, the initial value being a pulse count value monitored for the first time after a closing signal is sent to the brake band.

[0035] Optionally, the device further comprises a second monitoring unit, a third determining unit and a exiting unit, wherein:

[0036] The second monitoring unit is configured to continuously monitor the pulse count value sent by the encoder within a first preset time duration after the open-loop zero servo control mode is started;

[0037] The third determining unit is configured to determine that the encoder malfunctions and the brake band is actually in the non-failure state when a variation value of the pulse count value within a second preset time duration is less than a preset second pulse count variation threshold.

[0038] The exiting unit is configured to exit the open-loop zero servo control mode when it is determined that the brake band is actually in the non-failure state.

[0039] The brake band failure protection method and device provided by the application can start the open-loop zero servo control mode when the brake band is in the failure state, determine a motor starting frequency matching a current falling speed of the lifting load in the open-loop zero servo control mode, control the motor to start at the motor starting frequency, control the lifting load to start descending from the falling speed by applying an upward pulling force to the lifting load by the motor, and adjust the running frequency of the motor from the motor starting frequency to a preset lowering frequency after the motor starts at the motor starting frequency, so as to control the lifting load to descend to the ground at a target speed corresponding to the lowering frequency. The application can start the open-loop zero servo control mode without adding any detection device and controller in the external environment when the brake band fails, safely control the lifting load to the ground in the case of effectively reducing the mechanical impact suffered by the lifting mechanism and improving the braking comfort, effectively improve the reliability and safety of the brake band failure protection, and do not need to act the anti-falling device, reduce the damage probability of the anti-falling device, and improve the reliability of the anti-falling device.

[0040] The above description is only a summary of the technical solutions of the application. In order to more clearly understand the technical means of the application, the application can be implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the specific embodiments of the application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description only relate to the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative effort based on the provided drawings.

[0042] Figure 1 A flow chart of the first brake band failure protection method provided by the embodiment of the present application is shown;

[0043] Figure 2 A flow chart of the second brake band failure protection method provided by the embodiment of the present application is shown;

[0044] Figure 3 A flow chart of the fourth brake band failure protection method provided by the embodiment of the present application is shown;

[0045] Figure 4 A flow chart of the sixth brake band failure protection method provided by the embodiment of the present application is shown;

[0046] Figure 5 A structural schematic diagram of the first brake band failure protection device provided by the embodiment of the present application is shown;

[0047] Figure 6 A structural schematic diagram of the second brake band failure protection device provided by the embodiment of the present application is shown;

[0048] Figure 7 A structural schematic diagram of the fourth brake band failure protection device provided by the embodiment of the present application is shown. DETAILED DESCRIPTION

[0049] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be completely conveyed to those skilled in the art.

[0050] As shown in Figure 1 the present embodiment proposes a first brake band failure protection method, which can include the following steps:

[0051] S101, when the brake band is in a failure state, starting an open-loop zero servo control mode;

[0052] The brake clutch can be a brake clutch in the lifting mechanism.

[0053] It can be understood that the load of the lifting mechanism, i.e., the lifting load, can include a cage and people, goods, etc. in the cage.

[0054] Specifically, the present application can be applied to a frequency converter or a frequency conversion all-in-one machine system of the lifting mechanism. For example, when the lifting mechanism is a crane, the present application can be applied to a frequency converter of the crane; for another example, when the lifting mechanism is a construction hoist, the present application can be applied to a frequency conversion all-in-one machine system of the construction hoist.

[0055] It should be noted that the zero servo in the prior art can be a closed-loop zero servo, which means that if the given running frequency of the motor is zero under the condition that the running instruction of the frequency converter or the frequency conversion all-in-one machine system is valid, the motor can have a large enough zero-speed torque and can always remain in a zero-speed state.

[0056] The closed-loop zero servo can be used in a closed-loop control mode. The present application can design an open-loop zero servo control mode, and when the brake clutch fails (including brake damage and brake torque deficiency, etc.), the open-loop zero servo control mode, i.e., the zero servo in the open-loop control mode, can be used to brake the lifting load and control the lifting load to descend to the ground at a certain speed, so as to ensure the safety of the lifting load.

[0057] S102, in the open-loop zero servo control mode: determining a motor starting frequency matched with the current falling speed of the lifting load;

[0058] Specifically, after entering the open-loop zero servo control mode, the present application can start to execute a series of control processes accordingly until the lifting load is controlled to the ground.

[0059] The falling speed can be the speed of the lifting load in the falling process. It can be understood that when the brake clutch fails, if the gear friction and wind resistance are ignored, the lifting load can be considered to fall in a free-fall motion, and at this time, the present application can use a free-fall speed calculation formula to estimate the falling speed.

[0060] Specifically, the application can estimate the falling speed of the lifting load by obtaining the pulse count value for measuring the gear rotation number sent by the encoder installed at the gear position, or can determine the falling speed of the lifting load by newly setting a speed sensor with high measurement accuracy in the lifting mechanism.

[0061] The motor starting frequency can be the running frequency of the motor during the starting process.

[0062] It should be noted that the lifting load can drag the motor to rotate during the falling process, and the falling speed of the lifting load corresponds to the dragged rotation speed of the motor. When the application determines that the brake band brake is invalid and enters the open-loop zero servo control mode, the current dragged rotation speed of the motor can be determined, and the motor can be started at the motor starting frequency corresponding to the dragged speed, so that the motor can directly reach the dragged speed during the starting process, effectively reducing the mechanical impact force suffered by the lifting mechanism due to braking of the lifting load, reducing the lifting mechanism loss, protecting the safety of the people or goods in the lifting load, and improving the comfort during braking.

[0063] Specifically, the application can calculate the current falling speed of the lifting load when entering the lifting open-loop control mode, then calculate the current dragged rotation speed of the motor according to the falling speed, and then calculate the corresponding running frequency, i.e. the motor starting frequency, according to the current dragged rotation speed of the motor.

[0064] S103, starting the motor at the motor starting frequency to control the lifting load to start descending from the falling speed by applying an upward pulling force to the lifting load through the motor;

[0065] The step S103 can be one execution step of the application in the open-loop zero servo control mode.

[0066] After calculating the motor starting frequency, the application can control the motor to start at the motor starting frequency, so that the lifting load can start descending from the falling speed when entering the open-loop zero servo control mode.

[0067] Specifically, during the process of controlling the motor to start at the motor starting frequency, the application can calculate the corresponding motor input current according to the weight, speed and falling acceleration of the lifting load, and input the motor input current into the motor, control the motor to rotate to apply an upward pulling force to the lifting load, output a large enough torque to the lifting load, effectively brake the lifting load in the accelerating falling state, control the lifting load to escape from the accelerating state, and make the lifting load start to descend at a constant speed from the falling speed when the open-loop zero servo control mode is started, avoiding the lifting load to re-enter the out-of-control and accelerating falling state.

[0068] S104, after the motor is started at the motor starting frequency, adjusting the operating frequency of the motor from the motor starting frequency to a preset lower frequency, so as to control the target speed corresponding to the lower frequency of the lifting load to drop to the ground.

[0069] It should be noted that step S104 can be one execution step of the present application in the open-loop zero servo control mode.

[0070] The lower frequency can be an operating frequency less than the motor starting frequency, or an operating frequency not less than the motor starting frequency.

[0071] The lower frequency can be set by the technician according to the actual working condition of the lifting mechanism, and the present application does not limit this.

[0072] The target speed can be the falling speed of the lifting load when the operating frequency of the motor is stable at the lower frequency. It can be understood that the target speed can be less than the falling speed corresponding to the motor starting frequency, and the target speed can also be not less than the falling speed corresponding to the motor starting frequency.

[0073] Optionally, when setting the target speed, the present application can prohibit setting the target speed too small to avoid insufficient motor output torque, and can also prohibit setting the target speed too large to avoid excessive mechanical impact on the lifting load when reaching the ground.

[0074] It should be noted that the present application can use the displacement sensor originally provided in the lifting mechanism to determine the height of the lifting load during the falling process, or can newly set a displacement sensor with higher measurement accuracy in the lifting mechanism to determine the height of the lifting load during the falling process, so as to determine whether the lifting load reaches the ground.

[0075] Specifically, the present application can directly exit the open-loop zero servo control mode after controlling the lifting load to reach the ground, and the base spring provided at the ground can support and brake the lifting load, reducing the consumption of control resources while ensuring the safety of the lifting load.

[0076] It can be understood that after the motor is started, the present application can control the falling speed of the lifting load by adjusting the operating frequency of the motor, and then controlling the rotating speed of the motor. When the operating frequency of the motor is greater, the rotating speed of the motor is greater, and the falling speed of the lifting load is greater; when the operating frequency of the motor is smaller, the rotating speed of the motor is smaller, and the falling speed of the lifting load is smaller.

[0077] Specifically, the motor running frequency can be adjusted to the preset lowering frequency after the motor is started, and the lowering speed of the lifting load can be adjusted to the target speed by adjusting the motor speed when the motor can output a large enough torque, until the lifting load is lowered to the ground, so as to reduce the braking impact suffered by the lifting load when reaching the ground and improve the safety of the lifting load.

[0078] Optionally, the target speed can be determined by the technician in advance, and then the corresponding lowering frequency can be determined according to the target speed.

[0079] Optionally, the motor running frequency can be adjusted after the preset time length of sending the starting instruction to the motor.

[0080] Optionally, the motor running frequency can be monitored after sending the starting instruction to the motor, and the motor can be determined to be started when the motor running frequency reaches the motor starting frequency. At this time, step S104 can include:

[0081] The motor running frequency is adjusted from the motor starting frequency to the lowering frequency when the motor running frequency reaches the motor starting frequency.

[0082] Optionally, the motor running frequency can be adjusted several times in stages during the process of lowering the lifting load to the ground after the motor is started. The lowering speed of the lifting load can be reduced several times when the motor can output a large enough torque, so as to further improve the safety of the lifting mechanism and reduce the mechanical impact suffered by the lifting mechanism. At this time, the lowering frequency can include a plurality of frequency values.

[0083] Optionally, after entering the open-loop zero servo control mode, the current lowering frequency of the motor can be adjusted to a smaller frequency value when the lifting load is lowered for a certain time length or height, and the lowering speed of the lifting load can be gradually reduced until the lifting load is lowered to the ground when the motor can output a large enough torque.

[0084] At this time, it is necessary to ensure that the motor can output a large enough torque to drag the lifting load to prevent it from falling uncontrollably again.

[0085] It should be noted that in the prior art, when the falling load is braked by the fall arrest device due to the failure of the holding brake, the fall arrest device may be damaged after multiple actions, and the reliability is low. In the prior art, the fall arrest device generally intervenes in braking when the falling speed of the lifting load is high, and at this time, the forced braking will produce strong mechanical impact force, which will damage the lifting load. In addition, after the fall arrest device forcibly brakes the lifting load, the lifting load may be suspended in the air for a long time, waiting for safety personnel to handle or rescue, and if the lifting load includes personnel, it is easy to cause panic and insecurity.

[0086] Compared with the prior art, the present application can set up an open-loop zero servo control mode without adding any external detection equipment and controllers, start the open-loop zero servo control mode when the holding brake fails, safely control the lifting load to the ground under the condition of effectively reducing the mechanical impact on the lifting mechanism and improving the braking comfort, effectively improve the reliability and safety of the holding brake failure protection, and do not need to act the fall arrest device, reduce the damage probability of the fall arrest device, and improve the reliability of the fall arrest device.

[0087] It should also be noted that in the actual working process of the lifting mechanism, the technical solution shown in Figure 1 may be used alone to protect the holding brake failure, and the fall arrest device is not needed to protect the holding brake failure, avoiding the damage problem caused by multiple actions of the fall arrest device.

[0088] Optionally, in the actual working process of the lifting mechanism, the technical solution shown in Figure 1 may be used alone to protect the holding brake failure in some period, and the fall arrest device may be used alone to protect the holding brake failure in some period, increasing the diversity of the holding brake failure protection mode and improving the utilization rate of the equipment.

[0089] Optionally, the present application can use the scheme shown in Figure 1 as the main scheme for holding brake failure protection, and use the fall arrest device as the backup scheme for holding brake failure protection. When the scheme shown in Figure 1 can be normally implemented, the scheme shown in Figure 1 is used to protect the holding brake failure, and if the scheme shown in Figure 1 cannot be normally implemented due to equipment maintenance or failure, etc., the fall arrest device can be used to protect the holding brake failure.

[0090] The brake failure protection method provided in the embodiment can start the open-loop zero servo control mode when the brake is in a failure state, determine a motor starting frequency matched with the current falling speed of the lifting load in the open-loop zero servo control mode, control the motor to start at the motor starting frequency to control the lifting load to start descending from the falling speed, and adjust the running frequency of the motor from the motor starting frequency to a preset lowering frequency to control the lifting load to descend to the ground at a target speed corresponding to the lowering frequency by applying an upward pulling force to the lifting load by the motor. The application can start the open-loop zero servo control mode without adding any detection device and controller in the external environment when the brake fails, safely control the lifting load to the ground in the case of effectively reducing the mechanical impact suffered by the lifting mechanism and improving the braking comfort, effectively improve the reliability and safety of the brake failure protection, and do not need to act the anti-falling device, reduce the damage probability of the anti-falling device, and improve the reliability of the anti-falling device.

[0091] Based on Figure 1 As shown in the steps, as Figure 2 The second brake failure protection method is provided in the embodiment, as shown in the steps. In the method, step S101 can be specifically step S201, and the method can further include step S202, wherein:

[0092] S201, when the brake is in a failure state and the falling speed of the lifting load is less than a preset speed threshold, starting an open-loop zero servo control mode;

[0093] It should be noted that the application can use the open-loop zero servo control mode and the anti-falling device to protect the brake from failure. Alternatively, the application can first attempt to start the open-loop zero servo control mode to protect the brake from failure when the brake fails, and if the open-loop zero servo control mode cannot effectively protect the brake from failure due to an abnormality, the application can attempt to start the anti-falling device to protect the brake from failure.

[0094] Specifically, the application can determine whether to start the open-loop zero servo control mode to protect the brake from failure or to start the anti-falling device to protect the brake from failure based on the falling speed of the lifting load.

[0095] Specifically, the application can first start the open-loop zero servo control mode to protect the lifting load from failure when the brake fails and the falling speed of the lifting load does not reach the speed threshold during the operation of the lifting mechanism.

[0096] The speed threshold can be determined by the technical personnel according to the actual working condition of the lifting mechanism, and the application does not limit it.

[0097] S202. When the holding brake is in a failed state and the falling speed of the lifting load is not less than the speed threshold, the fall arrestor shall be activated to brake the lifting load.

[0098] It is understandable that if the open-loop zero servo control mode cannot effectively brake the lifting load, the falling speed of the lifting load will continue to increase. When the falling speed of the lifting load increases to the point of reaching or exceeding the speed threshold, the present invention can determine that the open-loop zero servo control mode is abnormal and activate the fall arrestor to brake and protect the lifting load.

[0099] Optionally, when the falling speed of the lifting load reaches the speed threshold, the present invention can exit the open-loop zero servo control mode and activate the fall arrestor separately to protect against brake failure. This can reduce the consumption of control resources and avoid conflicts in control logic.

[0100] Optionally, when the falling speed of the lifting load reaches the speed threshold, the present invention can also activate the fall arrestor to protect against brake failure without exiting the open-loop zero servo control mode, while continuing to execute the open-loop zero servo control mode. In this case, dual braking can be provided for the lifting load, improving the safety protection against brake failure.

[0101] It should be noted that this invention uses both open-loop zero-servo control mode and fall arrestor to perform brake failure protection, which can achieve redundant protection and further improve the reliability and safety of brake failure protection.

[0102] The brake failure protection method proposed in this embodiment uses both open-loop zero servo control mode and fall arrestor to protect the brake from failure, thereby achieving redundant protection and further improving the reliability and safety of brake failure protection.

[0103] based on Figure 1 As shown in the steps, this embodiment proposes a third method for protecting against brake failure. In this method, step S102 may include:

[0104] The motor is started at a preset input current and starting frequency to increase the torque output capability of the motor. By applying an upward pulling force to the lifting load, the lifting load is controlled to descend from the falling speed.

[0105] It is understandable that the greater the input current of a motor, the stronger its torque output capability, and the greater the torque the motor can output. This invention can improve the torque output capability of a motor by increasing its input current.

[0106] The preset input current can be greater than the rated current of the motor, for example, it can be 1.5 times the rated current of the motor.

[0107] Optionally, the preset input current can be determined by technicians based on the actual working conditions of the lifting mechanism, and this invention does not limit this.

[0108] It should be noted that, in the open-loop zero servo control mode of this invention, the corresponding motor input current calculated based on data such as lifting load, speed, and descent acceleration will generally not exceed its rated current.

[0109] Specifically, in the open-loop zero servo control mode, the present invention can set the motor input current to a preset input current, thereby increasing the motor's torque output capability. This effectively brakes the load during the descent of the lifting load, preventing it from losing control and falling again, and further improving the safety and reliability of controlling the descent of the lifting load.

[0110] The brake failure protection method proposed in this embodiment can set the motor input current to a preset input current, thereby increasing the motor's torque output capability. This effectively brakes the load during the controlled descent of the lifting load, preventing it from falling out of control again and further improving the safety and reliability of controlling the descent of the lifting load.

[0111] based on Figure 1 The steps shown are as follows: Figure 3 As shown, this embodiment proposes a fourth method for protecting against brake failure. Before step S101, this method may further include steps S301 and S302, wherein:

[0112] S301. After sending a closing signal to the holding brake, continuously monitor the pulse count value sent by the encoder to measure the number of gear rotations.

[0113] The encoder can be a device installed on the gear in the lifting mechanism to measure the number of rotations of the gear.

[0114] Specifically, after sending a closing signal to the holding brake, the present invention can continuously monitor the pulse count value sent by the encoder for a preset period of time, and determine whether the gear is still rotating and estimate the rotation speed and acceleration of the gear based on the change value of the pulse count value, thereby determining whether the holding brake is effectively braking the lifting load, and thus determining whether the holding brake has failed.

[0115] S302. When the change in pulse count value is greater than the preset first pulse count change threshold, the holding brake is determined to be in a failed state. The change in pulse count value is the difference between the currently monitored pulse count value and the initial value. The initial value is the pulse count value monitored for the first time after the closing signal is sent to the holding brake.

[0116] It should be noted that after sending a closing signal to the brake, this invention can continuously monitor the pulse count value sent by the encoder. Specifically, this invention can determine the first pulse count value detected during the monitoring period as the initial value of the pulse count value, and in subsequent monitoring processes, the real-time monitored value of the pulse count value is subtracted from the initial value, and the value obtained by subtraction is determined as the change value of the pulse count value.

[0117] It is understandable that when the brake is intact and not malfunctioning, the pulse count value will not change, i.e., the change in the pulse count value is zero. When the brake fails, the pulse count value will change. When the change in the pulse count value is greater than the first pulse count change threshold, it indicates that the gear is continuously rotating and the lifting load is in a falling state. This invention can determine that the brake has failed.

[0118] The threshold for the change in the first pulse count can be determined by technicians based on the actual working conditions of the lifting mechanism; this invention does not limit this.

[0119] Optionally, an audio player can be installed on the lifting mechanism. In this case, the fourth method for brake failure protection can also include:

[0120] When the brake failure is confirmed, the audio player is instructed to output a brake failure alarm to prompt technicians to promptly inspect and handle the brake failure, thereby improving fault handling efficiency and effectively preventing safety accidents.

[0121] The brake failure protection method proposed in this embodiment can effectively determine whether the brake has failed, thereby determining whether to activate the open-loop zero servo control mode, further improving the safety and reliability of the lifting mechanism.

[0122] based on Figure 3 As shown in the steps, this embodiment proposes a fifth method for protecting against brake failure. This method, after step S101, may further include steps S303, S304, and S305, wherein:

[0123] S303. Within the first preset time period, continuously monitor the pulse count value sent by the encoder;

[0124] It should be noted that the maintenance personnel may misoperate the gear provided with the encoder during maintenance, causing the change value of the pulse count value to change, and when the change value is greater than the first pulse count change threshold, the open-loop zero servo control mode will be misstarted.

[0125] When the open-loop zero servo control mode is misstarted, the holding brake is actually not failed, and at this time, the open-loop zero servo control mode may not be able to impact the braking force of the open holding brake for the operation control of the motor and the lifting load, and the open-loop zero servo control mode cannot control the lifting load to descend, and the lifting load is still in a stationary state. However, the holding brake will also be impacted in the open-loop zero servo control mode, and long-term impact may cause damage to the holding brake, reducing the reliability of the holding brake.

[0126] Specifically, after entering the open-loop zero servo control mode, the change value of the pulse count value can be continuously monitored within the first preset time period, and if the change value is less than a certain specific value or does not change, it can be determined that the start of the open-loop zero servo control mode this time is triggered by the misoperation of the encoder, and it is actually not failed.

[0127] The first preset time period can be determined by the technician according to the actual working condition of the lifting mechanism and maintenance, and the present application does not limit it.

[0128] S304、When the change value of the pulse count value within the second preset time period is less than the preset second pulse count change threshold, it is determined that the encoder is misoperated, and it is determined that the holding brake is actually in a non-failed state;

[0129] The second preset time period can be determined by the technician according to the actual working condition of the lifting mechanism and maintenance, and the present application does not limit it.

[0130] The second pulse count change threshold can also be determined by the technician according to the actual working condition of the lifting mechanism and maintenance, and the present application does not limit it.

[0131] Optionally, the second pulse count change threshold can be zero. At this time, after entering the open-loop zero servo control mode, if it is continuously monitored that the change value of the pulse count value does not change within the second preset time period, it can be determined that the start of the open-loop zero servo control mode this time is triggered by the misoperation of the encoder, so that it can be determined that the holding brake is actually not failed. Of course, the second pulse count change threshold can also be zero.

[0132] S305、When it is determined that the holding brake is actually in a non-failed state, the open-loop zero servo control mode is exited.

[0133] Specifically, the present invention can stop executing control commands in the open-loop zero-servo control mode and exit the open-loop zero-servo control mode when it is determined that the holding brake has not actually failed, thereby reducing the consumption of control resources.

[0134] Optionally, if the change in pulse count value within the first preset time period is not less than the second pulse count change threshold within the second preset time period, the present invention can determine that the holding brake has actually failed, and thus continue to execute the control commands in the open-loop zero servo control mode to control the lifting load to descend to the ground.

[0135] The brake failure protection method proposed in this embodiment can avoid the false start of the open-loop zero servo control mode caused by encoder malfunction, thereby avoiding equipment damage to the brake caused by the false start of the open-loop zero servo control mode, enhancing the protection of the brake and improving the reliability of the brake.

[0136] based on Figure 1 The steps shown are as follows: Figure 4 As shown, this embodiment proposes a sixth method for protecting against brake failure. In this method, step S102 may include steps S401 and S402, wherein:

[0137] S401. Determine the motor drive speed that matches the falling speed;

[0138] Specifically, the present invention can determine the motor drive speed by utilizing the relationship between the falling speed of the lifting load and the motor drive speed.

[0139] Optionally, step S401 may include:

[0140] The preset first pulse count change threshold is input into the speed calculation model to obtain the motor drive speed output by the speed calculation model; wherein, the speed calculation model is:

[0141]

[0142] Where Rl is the motor drive speed, k is the transmission ratio of the motor reducer, Zp is the number of teeth of the pinion installed on the encoder, g is the gravitational acceleration, m is the module of the pinion, Pf is the preset first pulse count change threshold, P1 is the pulse count value of one revolution of the encoder, and Zj is the number of teeth of the gear meshed with the rack.

[0143] Among them, the threshold for the change in the first pulse count is... Figure 3 The threshold value for the first pulse count change in the technical solution shown is the same.

[0144] The threshold for the change in the first pulse count can be set by technicians according to the actual working conditions of the lifting mechanism, and this invention does not limit this setting.

[0145] It should be noted that in the open-loop zero servo control mode, the application can calculate the falling height of the lifting load according to formula (1):

[0146]

[0147] The falling speed of the lifting load can be calculated by the application using formula (2), i.e. the free-fall acceleration formula with zero initial speed:

[0148]

[0149] Wherein, Vt is the falling speed.

[0150] Specifically, the application can calculate and output the motor drag speed by the speed calculation model when entering the open-loop zero servo control mode, i.e. starting the speed calculation model.

[0151] S402, calculate the motor starting frequency matched with the motor drag speed.

[0152] Specifically, the application can calculate the motor starting frequency according to the relationship between the motor drag speed and the motor starting frequency.

[0153] Optionally, step S402 can include:

[0154] Input the motor drag speed into the frequency calculation model to obtain the motor starting frequency output by the frequency calculation model; wherein:

[0155]

[0156] Wherein, fs is the motor starting frequency, F is the rated frequency of the motor, Rl is the motor drag speed, and R is the rated speed of the motor.

[0157] Specifically, the application can calculate the motor starting frequency by using the frequency calculation model.

[0158] The brake band failure protection method proposed in the embodiment can improve the calculation efficiency of determining the motor starting frequency and guarantee the effective implementation of the brake band failure protection.

[0159] Corresponding to the method shown in Figure 1 , as shown in Figure 5 , the embodiment proposes a first brake band failure protection device, which can include a first starting unit 101, a first determining unit 102, a control unit 103 and an adjustment unit 104, wherein:

[0160] The first starting unit 101 is configured to execute: starting the open-loop zero servo control mode when the band brake is in the failure state.

[0161] The band brake can be a band brake in a lifting mechanism. The lifting mechanism can be a mechanical device for lifting people, goods and the like in construction sites, high-rise buildings and the like, such as construction hoists, cranes and hoists.

[0162] It can be understood that the load of the lifting mechanism, i.e. the lifting load, can include a cage and people, goods and the like in the cage.

[0163] Specifically, the present application can be applied to a frequency converter or a frequency conversion all-in-one machine system of a lifting mechanism.

[0164] The first determination unit 102 is configured to execute: in the open-loop zero servo control mode, determining a motor starting frequency matched with the current falling speed of the lifting load.

[0165] Specifically, the present application can start a series of control processes accordingly after entering the open-loop zero servo control mode, until the lifting load is controlled to the ground.

[0166] The falling speed can be the speed of the lifting load in the falling process. It can be understood that when the band brake fails, if the gear friction and wind resistance and other resistances are ignored, it can be considered that the lifting load will appear free-fall motion type falling, at this time the present application can use the free-fall speed calculation formula to estimate its falling speed.

[0167] Specifically, the present application can estimate the falling speed of the lifting load by obtaining the pulse count value for measuring the gear rotation turns sent by the encoder installed at the gear position, or can set a speed sensor with high measurement accuracy in the lifting mechanism to determine the falling speed of the lifting load.

[0168] The motor starting frequency can be the running frequency of the motor in the starting process.

[0169] Specifically, the present application can calculate the current falling speed of the lifting load when entering the open-loop control mode of the lifting, and then calculate the current dragged speed of the motor according to the falling speed, and then calculate the corresponding running frequency, i.e. the motor starting frequency, according to the current dragged speed of the motor.

[0170] The control unit 103 is configured to execute: controlling the motor to start at the motor starting frequency, so as to control the lifting load to start descending from the falling speed by the motor applying a direction upward pulling force to the lifting load.

[0171] The control unit 103 can be an execution unit for realizing the open-loop zero servo control mode.

[0172] The present application can control the motor to start at the motor starting frequency after calculating the motor starting frequency, so that the lifting load can start to descend from the falling speed when entering the open-loop zero servo control mode.

[0173] Specifically, during the process of controlling the motor to start at the motor starting frequency, the present application can calculate the corresponding motor input current according to the weight, speed and falling acceleration of the lifting load, and input the motor input current into the motor, control the motor to rotate to exert an upward pulling force on the lifting load, output a large enough torque to the lifting load, effectively brake the lifting load in the accelerating falling state, control the lifting load to escape from the accelerating state, and make the lifting load start to descend at a constant speed from the falling speed when the open-loop zero servo control mode starts, avoiding the lifting load to re-enter the state of uncontrolled and accelerating falling.

[0174] The adjusting unit 104 is configured to perform: after the motor starts at the motor starting frequency, adjusting the operating frequency of the motor from the motor starting frequency to a preset lowering frequency, to control the lifting load to descend to the ground at a target speed corresponding to the lowering frequency.

[0175] The adjusting unit 104 can be an execution unit for realizing the open-loop zero servo control mode.

[0176] The lowering frequency can be an operating frequency less than the motor starting frequency, or an operating frequency not less than the motor starting frequency.

[0177] The lowering frequency can be set by the technician according to the actual working condition of the lifting mechanism, and the present application does not limit it.

[0178] The target speed can be the falling speed of the lifting load when the operating frequency of the motor is stable at the lowering frequency. It can be understood that the target speed can be less than the falling speed corresponding to the motor starting frequency, and the target speed can also be not less than the falling speed corresponding to the motor starting frequency.

[0179] Optionally, when setting the target speed, the present application can prohibit setting the target speed too small to avoid insufficient motor output torque, and can also prohibit setting the target speed too large to avoid the lifting load suffering from excessive mechanical impact when reaching the ground.

[0180] It should be noted that the present application can determine the height of the lifting load in the falling process by using the displacement sensor originally provided in the lifting mechanism, or can determine the height of the lifting load in the falling process by newly providing a displacement sensor with higher measurement accuracy in the lifting mechanism, so as to determine whether the lifting load reaches the ground.

[0181] Specifically, the present application can directly exit the open-loop zero servo control mode after the lifting load reaches the ground, and the base spring provided at the ground is used to support and brake the lifting load, thereby reducing the consumption of control resources while ensuring the safety of the lifting load.

[0182] It can be understood that after the motor starts, the present application can control the speed of the motor and the falling speed of the lifting load by adjusting the operating frequency of the motor. When the operating frequency of the motor is greater, the speed of the motor is greater, and the falling speed of the lifting load is greater. When the operating frequency of the motor is smaller, the speed of the motor is smaller, and the falling speed of the lifting load is smaller.

[0183] Specifically, the present application can adjust the operating frequency of the motor from the motor starting frequency to the preset lowering frequency after the motor completes starting, and adjust the falling speed of the lifting load to the target speed by adjusting the speed of the motor under the condition that the motor can output a large enough torque, so as to control the lifting load to descend to the ground, reduce the braking impact suffered by the lifting load when reaching the ground, and improve the safety of the lifting load.

[0184] Optionally, the present application can determine the target speed by the technical personnel in advance, and then determine the corresponding lowering frequency according to the target speed.

[0185] Optionally, the present application can adjust the operating frequency of the motor after a preset time length of sending the starting instruction to the motor.

[0186] Optionally, the present application can start monitoring the operating frequency of the motor after sending the starting instruction to the motor, and when it is monitored that the operating frequency of the motor reaches the motor starting frequency, it can be determined that the motor completes starting. At this time, the adjusting unit 104 is configured to perform:

[0187] When the operating frequency of the motor reaches the motor starting frequency, the operating frequency of the motor is adjusted from the motor starting frequency to the lowering frequency.

[0188] It should be noted that the first determining unit 102, the control unit 103 and the adjusting unit 104 can constitute an open-loop zero servo control unit as a whole. When the condition of starting the open-loop zero servo control mode is met, the present application can trigger the open-loop zero servo control unit, that is, trigger the first determining unit 102, the control unit 103 and the adjusting unit 104 in sequence to realize the brake band brake failure protection.

[0189] Compared with the prior art, the application can set an open-loop zero servo control mode without adding any detection device and controller outside, start the open-loop zero servo control mode when the holding brake fails, safely control the lifting load to the ground in the case of effectively reducing the mechanical impact suffered by the lifting mechanism and improving braking comfort, effectively improve the reliability and safety of the holding brake failure protection, and do not need to actuate the fall protector, reduce the damage probability of the fall protector, and improve the reliability of the fall protector.

[0190] The holding brake failure protection device provided in the embodiment can start an open-loop zero servo control mode without adding any detection device and controller outside when the holding brake fails, safely control the lifting load to the ground in the case of effectively reducing the mechanical impact suffered by the lifting mechanism and improving braking comfort, effectively improve the reliability and safety of the holding brake failure protection, and do not need to actuate the fall protector, reduce the damage probability of the fall protector, and improve the reliability of the fall protector.

[0191] Based on Figure 5 As Figure 6 shown, the second holding brake failure protection device is provided in the embodiment. In the device, the first starting unit 101 is configured to perform:

[0192] starting the open-loop zero servo control mode when the holding brake is in a failure state and the falling speed of the lifting load is less than a preset speed threshold;

[0193] It should be noted that the application can use the open-loop zero servo control mode and the fall protector to protect the holding brake from failure. Alternatively, the application can first attempt to start the open-loop zero servo control mode to protect the holding brake from failure when the holding brake fails, and if the open-loop zero servo control mode cannot effectively protect the holding brake from failure due to an abnormality, the application can attempt to start the fall protector to protect the holding brake from failure.

[0194] Specifically, the application can determine whether to start the open-loop zero servo control mode to protect the holding brake from failure or start the fall protector to protect the holding brake from failure based on the falling speed of the lifting load.

[0195] Specifically, the application can first start the open-loop zero servo control mode to protect the lifting load from failure when the holding brake fails and the falling speed of the lifting load does not reach the speed threshold during the operation of the lifting mechanism.

[0196] The speed threshold can be determined by the technician according to the actual working condition of the lifting mechanism, and the application does not limit this.

[0197] At this time, the device further comprises a second starting unit 201; the second starting unit 201 is configured to execute:

[0198] When the brake band brake is in the failure state, and the falling speed of the lifting load is not less than the speed threshold value, the anti-falling device is started to brake the lifting load.

[0199] It can be understood that if the open-loop zero servo control mode cannot effectively brake the lifting load, the falling speed of the lifting load will continue to increase, and when the falling speed of the lifting load increases to reach or exceed the speed threshold value, the application can determine that the open-loop zero servo control mode is abnormal, and the anti-falling device is started to brake and protect the lifting load.

[0200] Optionally, when the falling speed of the lifting load reaches the speed threshold value, the application can exit the open-loop zero servo control mode, and only enable the anti-falling device to perform brake band brake failure protection, at this time, the consumption of control resources can be reduced, and control logic conflicts can be avoided.

[0201] Optionally, when the falling speed of the lifting load reaches the speed threshold value, the application can also not need to exit the open-loop zero servo control mode, and start the anti-falling device to perform brake band brake failure protection while continuing to execute the open-loop zero servo control mode, at this time, the lifting load can be provided with double braking, and the safety protection of the brake band brake failure can be improved.

[0202] It should be noted that the application uses the open-loop zero servo control mode and the anti-falling device to perform brake band brake failure protection, which can realize redundant protection and further improve the reliability and safety of the brake band brake failure protection.

[0203] The brake band brake failure protection device provided in the embodiment uses the open-loop zero servo control mode and the anti-falling device to perform brake band brake failure protection, which can realize redundant protection and further improve the reliability and safety of the brake band brake failure protection.

[0204] Based on Figure 5 , the third brake band brake failure protection device is provided in the embodiment. In the device, the control unit 103 is configured to execute:

[0205] The motor is started at a preset input current and a motor starting frequency, so that the lifting load starts to descend from the falling speed by the motor applying an upward pulling force to the lifting load while improving the torque output capability of the motor.

[0206] It is understandable that the greater the input current of a motor, the stronger its torque output capability, and the greater the torque the motor can output. This invention can improve the torque output capability of a motor by increasing its input current.

[0207] The preset input current can be greater than the rated current of the motor, for example, it can be 1.5 times the rated current of the motor.

[0208] Optionally, the preset input current can be determined by technicians based on the actual working conditions of the lifting mechanism, and this invention does not limit this.

[0209] It should be noted that, in the open-loop zero servo control mode of this invention, the corresponding motor input current calculated based on data such as lifting load, speed, and descent acceleration will generally not exceed its rated current.

[0210] Specifically, in the open-loop zero servo control mode, the present invention can set the motor input current to a preset input current, thereby increasing the motor's torque output capability. This effectively brakes the load during the descent of the lifting load, preventing it from losing control and falling again, and further improving the safety and reliability of controlling the descent of the lifting load.

[0211] The brake failure protection device proposed in this embodiment can set the motor input current to a preset input current. By increasing the motor input current, the torque output capability of the motor can be improved, and the load can be effectively braked during the control of the lifting load descent, preventing the lifting load from falling out of control again, and further improving the safety and reliability of controlling the lifting load descent.

[0212] based on Figure 5 ,like Figure 7 As shown, this embodiment proposes a fourth type of brake failure protection device. This device further includes: a first monitoring unit 301 and a second determining unit 302, wherein:

[0213] The first monitoring unit 301 is configured to perform the following: before starting the open-loop zero servo control mode when the holding brake is in a failed state, after sending a closing signal to the holding brake, continuously monitor the pulse count value sent by the encoder to measure the number of gear rotations.

[0214] The encoder can be a device installed on the gear in the lifting mechanism to measure the number of rotations of the gear.

[0215] Specifically, the application can continuously monitor the pulse count value sent by the encoder within a preset time period after sending the closing signal to the brake, determine whether the gear is still rotating and estimate the rotating speed and acceleration of the gear according to the change value of the pulse count value, so as to determine whether the brake effectively brakes the lifting load and whether the brake is invalid.

[0216] The second determination unit 302 is configured to perform: when the change value of the pulse count value is greater than a preset first pulse count change threshold, determining that the brake is in an invalid state, the change value of the pulse count value being a difference between the currently monitored pulse count value and an initial value, the initial value being the pulse count value first monitored after sending the closing signal to the brake.

[0217] It should be noted that the application can continuously monitor the pulse count value sent by the encoder after sending the closing signal to the brake. In the application, the pulse count value first monitored during the period can be determined as the initial value of the pulse count value, and in the subsequent monitoring process, the real-time monitoring value of the pulse count value is subtracted from the initial value, and the value obtained by the subtraction is determined as the change value of the pulse count value.

[0218] It can be understood that, in the case that the brake is intact, i.e. not invalid, the pulse count value will not change, i.e. the change value of the pulse count value is zero; when the brake is invalid, the pulse count value will change, and when the change value of the pulse count value is greater than the first pulse count change threshold, it indicates that the gear is continuously rotating and the lifting load is in a falling state, and the application can determine that the brake is invalid.

[0219] The first pulse count change threshold can be determined by the technician according to the actual working condition of the lifting mechanism, and the application does not limit this.

[0220] Optionally, an audio player can be arranged on the lifting mechanism. At this time, the fourth brake invalidation protection device can further include: an alarm unit; wherein the alarm unit is configured to perform:

[0221] When it is determined that the brake is invalid, the audio player is instructed to output a brake invalidation alarm to prompt the technician to check and handle the fault of the brake in time, improve the fault handling efficiency and effectively avoid the occurrence of safety accidents.

[0222] The brake invalidation protection device proposed in the embodiment can effectively determine whether the brake is invalid, so as to determine whether to start the open-loop zero-servo control mode, and further improve the safety and reliability of the lifting mechanism.

[0223] Based on the above, the application can effectively determine whether the brake is invalid, so as to determine whether to start the open-loop zero-servo control mode, and further improve the safety and reliability of the lifting mechanism. Figure 7The fifth brake band failure protection device is provided in the embodiment. The device also comprises a second monitoring unit, a third determining unit and a quitting unit, wherein:

[0224] The second monitoring unit is configured to continuously monitor the pulse count value sent by the encoder within a first preset time period after starting the open-loop zero servo control mode.

[0225] The third determining unit is configured to determine that the encoder malfunctions and the brake band is actually in a non-failure state when the change value of the pulse count value within a second preset time period is less than a preset second pulse count change threshold.

[0226] The quitting unit is configured to quit the open-loop zero servo control mode when it is determined that the brake band is in the actual non-failure state.

[0227] It should be noted that the maintenance personnel may misoperate the gear provided with the encoder during maintenance, resulting in a change in the change value of the pulse count value. When the change value is greater than the first pulse count change threshold, the open-loop zero servo control mode will be misstarted.

[0228] When the open-loop zero servo control mode is misstarted, the brake band is actually not failed. At this time, the open-loop zero servo control mode may not be able to impact the braking force of the brake band for the operation control of the motor and the lifting load, and the open-loop zero servo control mode cannot control the lifting load to descend, and the lifting load is still in a stationary state. However, the brake band will also be impacted in the open-loop zero servo control mode, and long-term impact may cause damage to the brake band, reducing the reliability of the brake band.

[0229] Specifically, the application can continuously monitor the change value of the pulse count value within a first preset time period after entering the open-loop zero servo control mode. If the change value is less than a certain specific value or does not change, it can be determined that the startup of the open-loop zero servo control mode is triggered by the encoder malfunction, and the encoder is actually not failed.

[0230] The first preset time period can be determined by the technician according to the actual working condition of the lifting mechanism and maintenance, and the application does not limit this.

[0231] The second preset time period can be determined by the technician according to the actual working condition of the lifting mechanism and maintenance, and the application does not limit this.

[0232] The second pulse count change threshold can also be determined by the technician according to the actual working condition of the lifting mechanism and maintenance, and the application does not limit this.

[0233] Specifically, the application can stop executing the control instruction in the open-loop zero servo control mode and exit the open-loop zero servo control mode when it is determined that the holding brake is actually not failed, thereby reducing the consumption of control resources.

[0234] Optionally, if the change value of the pulse count value in the second preset time period is not less than the second pulse count change threshold value within the first preset time period, the application can determine that the holding brake is actually failed, thereby continuing to execute the control instruction in the open-loop zero servo control mode to control the lifting load to drop to the ground.

[0235] The holding brake failure protection device provided in the embodiment can avoid the misstart of the open-loop zero servo control mode caused by the misoperation of the encoder, thereby avoiding the equipment damage of the holding brake caused by the misstart of the open-loop zero servo control mode, enhancing the protection of the holding brake, and improving the reliability of the holding brake.

[0236] Based on Figure 5 The sixth holding brake failure protection device is provided in the embodiment. In the device, the first determination unit 102 can include a fourth determination unit and a frequency calculation unit, wherein:

[0237] The fourth determination unit is configured to determine the motor drag rotation speed matched with the falling speed of the lifting load.

[0238] Specifically, the application can determine the motor drag rotation speed by using the relationship between the falling speed of the lifting load and the motor drag rotation speed.

[0239] Optionally, the fourth determination unit can include a first input unit and a first obtaining unit, wherein:

[0240] The first input unit is configured to input a preset first pulse count change threshold value into the rotation speed calculation model.

[0241] The first obtaining unit is configured to obtain the motor drag rotation speed output by the rotation speed calculation model, wherein the rotation speed calculation model is:

[0242]

[0243] wherein Rl is the motor drag rotation speed, k is the transmission ratio of the motor reducer, Zp is the number of teeth of the pinion installed on the encoder, g is the acceleration of gravity, m is the modulus of the pinion, Pf is the preset first pulse count change threshold value, P1 is the pulse count value of one rotation of the encoder, and Zj is the number of gear teeth engaged with the rack.

[0244] The first pulse count change threshold value can be set by the technician according to the actual working condition of the lifting mechanism, and the application does not limit it.

[0245] a frequency calculation unit configured to perform: calculating a motor starting frequency matched with the motor drag speed.

[0246] Specifically, the motor starting frequency can be calculated according to the relationship between the motor drag speed and the motor starting frequency.

[0247] Optionally, the frequency calculation unit can comprise: a second input unit and a second obtaining unit; wherein:

[0248] the second input unit is configured to perform: inputting the motor drag speed into a frequency calculation model;

[0249] the second obtaining unit is configured to perform: obtaining the motor starting frequency output by the frequency calculation model; wherein:

[0250]

[0251] wherein, fs is the motor starting frequency, F is the rated frequency of the motor, Rl is the motor drag speed, and R is the rated speed of the motor.

[0252] Specifically, the motor starting frequency can be calculated by using the frequency calculation model.

[0253] The brake band failure protection device can improve the calculation efficiency of the motor starting frequency and ensure the effective implementation of the brake band failure protection.

[0254] It should be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a" does not exclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0255] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the scope of claims of the present application.

Claims

1. A method of protecting against failure of a band brake, characterized by The method comprises: starting an open-loop zero servo control mode when the holding brake is in a failure state; in the open-loop zero servo control mode: determining a motor starting frequency matched with a current falling speed of the lifting load; controlling the motor to start at the motor starting frequency to control the lifting load to start descending from the falling speed by the motor applying an upward pulling force to the lifting load; and adjusting a running frequency of the motor from the motor starting frequency to a preset lowering frequency to control the lifting load to descend to the ground at a target speed corresponding to the lowering frequency after the motor starts at the motor starting frequency. The method further comprises: starting the open-loop zero servo control mode when the holding brake is in a failure state and the falling speed of the lifting load is not less than the speed threshold. The method further comprises: The rotational speed calculation model is: ; R l is the motor driving speed, k is the transmission ratio of the motor reducer, Z p is the number of teeth of the pinion installed by the encoder, g is the acceleration of gravity, m is the modulus of the pinion, P f is the preset first pulse count change threshold, P1 is the pulse count value of one revolution of the encoder, Z j is the number of gear teeth engaged by the rack , V t is the current falling speed of the lifting load; s is the drop height of the lifting load; The frequency calculation model is: ; fs is the motor starting frequency, F is the rated frequency of the motor, R l is the motor drag speed, R is the rated speed of the motor; starting the open-loop zero servo control mode when the holding brake is in a failure state and the falling speed of the lifting load is not less than the speed threshold. The method further comprises:

2. The method of claim 1, wherein, monitoring the pulse count value sent by the encoder to measure the number of gear rotations continuously after sending the closing signal to the holding brake; determining that the holding brake is in a failure state when the change value of the pulse count value is greater than the preset first pulse count change threshold, the change value of the pulse count value being the difference between the currently monitored pulse count value and an initial value, and the initial value being the pulse count value monitored for the first time after sending the closing signal to the holding brake. The method further comprises: monitoring the pulse count value sent by the encoder continuously within a first preset time length, and determining that the encoder malfunctions and the holding brake is actually in a non-failure state when the change value of the pulse count value within a second preset time length is less than a preset second pulse count change threshold after starting the open-loop zero servo control mode.

3. The method of claim 1, wherein, The method further comprises: quitting the open-loop zero servo control mode when it is determined that the holding brake is in an actual non-failure state. The method comprises:

4. The method of claim 3, wherein, ​ ​ ​ 5. A holding brake failure protection device characterized by comprising: ​ The first starting unit, the first determining unit, the control unit and the adjusting unit, wherein: The first starting unit is configured to execute: starting an open-loop zero servo control mode when the band brake is in a failure state; The first determining unit is configured to execute: determining a motor starting frequency matched with a current falling speed of the lifting load in the open-loop zero servo control mode; The control unit is configured to execute: controlling the motor to start at the motor starting frequency to control the lifting load to start descending from the falling speed by the motor applying an upward pulling force to the lifting load; The adjusting unit is configured to execute: adjusting a running frequency of the motor from the motor starting frequency to a preset lowering frequency after the motor starts at the motor starting frequency, to control the lifting load to descend to the ground at a target speed corresponding to the lowering frequency; The first determining unit comprises: a fourth determining unit and a frequency calculation unit; wherein: The fourth determining unit comprises: a first input unit and a first obtaining unit; The first input unit is configured to execute: inputting a preset first pulse count change threshold into a rotating speed calculation model; The first obtaining unit is configured to execute: obtaining a motor drag rotating speed output by the rotating speed calculation model; wherein the rotating speed calculation model is: ； R l is the motor driving speed, k is the transmission ratio of the motor reducer, Z p is the number of teeth of the pinion installed by the encoder, g is the acceleration of gravity, m is the modulus of the pinion, P f is the preset first pulse count change threshold, P1 is the pulse count value of one rotation of the encoder, Z j is the number of gear teeth engaged by the rack wherein , V t is the current falling speed of the lifting load; s is the drop height of the lifting load; The frequency calculation unit comprises: a second input unit and a second obtaining unit; wherein: The second input unit is configured to execute: inputting the motor drag rotating speed into a frequency calculation model; The second obtaining unit is configured to execute: obtaining a motor starting frequency output by the frequency calculation model; wherein: ； Wherein, fs is the motor starting frequency, F is the rated frequency of the motor, Rl is the motor drag rotating speed, and R is the rated rotating speed of the motor; The control unit is configured to execute: Controlling the motor to start at a preset input current and the motor starting frequency to control the lifting load to start descending from the falling speed by the motor applying an upward pulling force to the lifting load in the case of improving the torque output capability of the motor.

6. The apparatus of claim 5, wherein, The first starting unit is configured to execute: Starting the open-loop zero servo control mode when the band brake is in a failure state and the falling speed of the lifting load is less than a preset speed threshold; The device further comprises: a second starting unit; the second starting unit is configured to execute: Starting the band brake to brake the lifting load when the band brake is in a failure state and the falling speed of the lifting load is not less than the speed threshold.

7. The apparatus of claim 5, wherein, The device further comprises: a first monitoring unit and a second determining unit, wherein: The first monitoring unit is configured to execute: continuously monitoring pulse count values for measuring rotating circle numbers of gears sent by an encoder after sending an on signal to the band brake before starting the open-loop zero servo control mode when the band brake is in a failure state; The second determining unit is configured to determine that the brake band is in the failure state when a variation value of the pulse count value is greater than a preset first pulse count variation threshold, the variation value of the pulse count value being a difference between a current monitored pulse count value and an initial value, the initial value being a pulse count value monitored for the first time after a closing signal is sent to the brake band.

8. The apparatus of claim 7, wherein, The device further comprises a second monitoring unit, a third determining unit and an exiting unit, wherein: The second monitoring unit is configured to continuously monitor the pulse count value sent by the encoder within a first preset time period after the open-loop zero servo control mode is started; The third determining unit is configured to determine that the encoder malfunctions and that the brake band is actually in a non-failure state when a variation value of the pulse count value within a second preset time period is less than a preset second pulse count variation threshold; The exiting unit is configured to exit the open-loop zero servo control mode when it is determined that the brake band is actually in the non-failure state.

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