Acceleration prediction-based elevator car sliding speed calculation method and brake release device

Abstract

The invention discloses an elevator car sliding speed calculation method based on acceleration prediction and a brake release device. According to the elevator car sliding speed calculation method based on acceleration prediction, the elevator car does uniform acceleration linear motion in the sliding process. At the beginning and the end of a detection period, the running speed of the elevator car is calculated based on the jumping times of pulse signals output by the incremental encoder, so that the acceleration in the detection period is calculated, and the running speed of the elevator car at any moment in the next detection period is calculated by utilizing the acceleration. On the premise that the resolution of the incremental encoder is not changed, the calculation frequency of the car sliding speed of the elevator car is improved, and elevator safety accidents caused by too low resolution of the incremental encoder are avoided. The brake releasing device calculates the car sliding speed of the elevator car by using the method in the period of outputting the brake releasing signal, and when the speed exceeds 0.3 m / s, the brake releasing device outputs brake contracting voltage to brake the elevator car.

Description

Technical Field

[0001] The present invention belongs to the technical field of elevator management, and relates to the management of elevator car slipping, and in particular to an elevator car slipping speed calculation method based on acceleration prediction and a brake release device. Background Art

[0002] The brake release device is an emergency electric control device designed for unexpected power outages or failures in the elevator system. The signal detection end of the brake release device always monitors the presence of mains power. When there is mains power, the device will not be put into operation. When there is no mains power, the brake will stop the elevator to prevent it from continuing to run. The manager can output the brake release voltage through the brake release device to release the brake and slide the car to the level floor to rescue the passengers trapped in the car. In this process, the sliding speed of the car needs to be detected at all times, and the car is usually judged to be overspeeding when the speed exceeds 0.3m / s, the brake stops output, the main engine brake is tightened, and the car stops running.

[0003] The position, direction of movement and speed of the elevator car need to be obtained through an encoder. In the elevator system, the encoder is usually installed on the motor shaft or traction wheel to convert the movement of the elevator motor shaft into an electrical signal output, including incremental encoders and absolute encoders. The incremental encoder outputs A-phase and B-phase pulse signals, and determines the rotation direction by detecting the phase difference between the A / B phases. The elevator car's sliding speed is obtained by detecting the number of signal jumps in a cycle.

[0004] During the brake release process, if the encoder resolution is low, the elevator car speed may exceed 0.3m / s, but the brake output will not stop before the next pulse signal arrives. If the elevator happens to be close to the bottom of the shaft at this time, a bottom collision accident may occur, resulting in casualties. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention proposes an elevator car slipping speed calculation method and a brake release device based on acceleration prediction, which uses the acceleration of the elevator car to predict the slipping speed before the next pulse signal arrives, thereby realizing real-time detection of the elevator car slipping speed and avoiding accidents caused by low encoder resolution.

[0006] The method for calculating the elevator car slipping speed based on acceleration prediction specifically includes the following steps:

[0007] Step 1: When the release device outputs the release voltage, the elevator car is regarded as performing uniformly accelerated linear motion, with initialization time t0=0 and speed V0=0.

[0008] Step 2: After a detection cycle T, calculate the speed V1 at time t1 according to the number of jumps of the incremental encoder output pulse signal, t1 = t0 + T.

[0009] Step 3: Use V0 and V1 to calculate the acceleration a1 of the elevator car during t0-t1, and use the acceleration a1 to estimate the speed V of the elevator car at any time point t in the next detection period t1-t2. t .

[0010] Step 4: When t = nT, calculate t according to the number of jumps of the incremental encoder output pulse signal. n The speed V at the moment n , then according to V n-1 、V n Calculate t n-1 ~t n The acceleration of the elevator car is a n , thereby calculating the elevator car in the next detection cycle t n ~t n+1 The velocity V at any time point t t . Where n is a positive integer, indicating the number of detection cycles.

[0011] Step 5: When V t When the speed is ≥0.3m / s, the brake voltage is output to stop the elevator car.

[0012] As a preference, V n =πRF n / 4P / T, where R represents the radius of the main engine traction wheel that drags the elevator car, P represents the resolution of the incremental encoder, and F n Indicates that in the nth detection cycle t n-1 ~t n The number of jumps of the internal incremental encoder output pulse signal.

[0013] As a preference, a n =(V n-1 -V n ) / T.

[0014] The elevator car release device based on acceleration prediction outputs the release voltage. The control cabinet detects the output signal of the encoder, calculates the acceleration according to the elevator car speed at the beginning and end of each cycle, and uses the acceleration to infer the speed of the elevator car at any time point in the next detection cycle. When the calculated speed of the elevator car exceeds 0.3m / s, the brake voltage is output to stop the elevator car.

[0015] The present invention has the following beneficial effects:

[0016] The present invention calculates the acceleration using the elevator car speed at the beginning and end of the detection cycle, so as to deduce the real-time speed of the elevator car at any time point, avoiding the speed calculation "vacuum period" caused by the low resolution of the encoder, and improving the safety of the elevator car operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the elevator car and counterweight suspension method;

[0018] Figure 2 This is a schematic diagram of the incremental encoder output signal;

[0019] Figure 3 This is the elevator car running speed diagram. DETAILED DESCRIPTION

[0020] The present invention will be further explained below with reference to the accompanying drawings;

[0021] like Figure 1 As shown in the figure, the encoder is installed on the motor shaft or traction sheave, converting the movement of the elevator motor shaft into an electrical signal output, thereby monitoring the motor speed, rotation direction and position of the car. The incremental encoder has an encoder disk with evenly spaced transparent and opaque parts inside, which rotates synchronously with the motor shaft and detects changes in light through paired light-emitting diodes or phototransistors. When the encoder disk rotates with the motor shaft, the transparent part allows light to pass through and be detected by the phototransistor, while the opaque part blocks the light, causing the incremental encoder to output a series of square wave pulses, such as Figure 2 As shown, the number of pulses is proportional to the angle of rotation of the motor shaft and the distance the elevator car moves linearly.

[0022] Assuming that the radius of the main engine traction wheel that pulls the elevator car is R mm, the elevator car travels 2πR / 2 mm when the main engine traction wheel rotates one circle. The resolution of the incremental encoder is P, so when the main engine traction wheel rotates one circle, the output signal of the incremental encoder jumps 4P times. If the number of jumps of the pulse signal in a detection cycle T is F, the running speed of the elevator car is V=πRF / 4P / T.

[0023] In order to improve the measurement frequency of the elevator car running speed without changing the resolution P of the incremental encoder, a method for calculating the elevator car slipping speed based on acceleration prediction is proposed, which specifically includes the following steps:

[0024] Step 1: When the release device outputs the release voltage, the elevator car is regarded as performing uniformly accelerated linear motion, with initialization time t0=0 and speed V0=0.

[0025] Step 2: After a detection cycle T, calculate the speed V1 at time t1 according to the number of jumps of the incremental encoder output pulse signal, t1 = t0 + T.

[0026] Step 3: Use V0 and V1 to calculate the acceleration a1 of the elevator car during t0-t1, and use the acceleration a1 to estimate the speed V of the elevator car at any time point t in the next detection period t1-t2. t .

[0027] Step 4: When t = nT, calculate t according to the number of jumps of the incremental encoder output pulse signal. n The speed V at the moment n , then according to V n-1 、V n Calculate t n-1 ~t n The acceleration of the elevator car is a n =(V n-1 -V n ) / T, thereby calculating the elevator car in the next detection cycle t n ~t n+1 The velocity V at any time point t t Where n is a positive integer, indicating the number of detection cycles, such as Figure 3 shown.

[0028] Step 5: When V t When the speed is ≥0.3m / s, the brake voltage is output to stop the elevator car.

[0029] The elevator car release device based on acceleration prediction outputs the release voltage. The control cabinet detects the output signal of the encoder, calculates the acceleration according to the elevator car speed at the beginning and end of each cycle, and uses the acceleration to infer the speed of the elevator car at any time point in the next detection cycle. When the calculated speed of the elevator car exceeds 0.3m / s, the brake voltage is output to stop the elevator car.

Claims

1. A method for calculating the elevator car slipping speed based on acceleration prediction, characterized in that: The specific steps include: Step 1: When the release device outputs the release voltage, the elevator car is considered to be in uniformly accelerated linear motion, with initialization time t0=0 and speed V0=0; Step 2: After a detection cycle T, calculate the elevator car sliding speed V1 at time t1 according to the number of jumps of the incremental encoder output pulse signal, t1 = t0 + T; Step 3: Use V0 and V1 to calculate the acceleration a1 of the elevator car during t0-t1, and use the acceleration a1 to estimate the speed V of the elevator car at any time point t in the next detection period t1-t2. t ; Step 4: When t = nT, calculate t according to the number of jumps of the incremental encoder output pulse signal. n The elevator car sliding speed V n , then according to V n-1 、V n Calculate t n-1 ~t n The acceleration of the elevator car is a n , thereby calculating the elevator car in the next detection cycle t n ~t n+1 The velocity V at any time point t t ; Where n is a positive integer, indicating the number of detection cycles.

2. The method for calculating the elevator car slipping speed based on acceleration prediction according to claim 1, characterized in that: When V t When the speed is ≥0.3m / s, the brake voltage is output to stop the elevator car.

3. The method for calculating the elevator car slipping speed based on acceleration prediction according to claim 1, characterized in that: V n =πRF n / 4P / T, where R represents the radius of the main engine traction wheel that drags the elevator car, P represents the resolution of the incremental encoder, and F n Indicates that in the nth detection cycle t n-1 ~t n The number of jumps of the internal incremental encoder output pulse signal.

4. The method for calculating the elevator car slipping speed based on acceleration prediction according to claim 1 or 3, characterized in that: a n =(V n-1 -V n ) / T。 5. An elevator car brake release device based on acceleration prediction, characterized in that: When the release device outputs the release voltage, the control cabinet detects the output signal of the encoder and uses the method described in any one of claims 1 to 3 to calculate the speed of the elevator car. When the calculated speed of the elevator car exceeds 0.3m / s, the brake voltage is output to stop the elevator car.

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