A detection method for a warehouse car ramp sliding

Abstract

The application discloses a detection method for slope sliding of a warehouse vehicle, and comprises the following steps: step 1: after the vehicle stops driving on a slope, a controller controls U-phase driving motor control signal PWM output 0 in a direct current motor H-bridge circuit, and V-phase upper and lower tube driving is closed; step 2: a voltage sampler AD samples bridge arm midpoint voltage information; step 3: according to the bridge arm midpoint voltage information obtained in step 2, it is judged whether the bridge arm midpoint voltage change is within a reasonable range, and whether the vehicle is in a slope sliding state, and the application controls bridge arm driving output motor control signal PWM through a controller on the basis of an original motor control scheme, when U-phase driving output is 0, it is equivalent to U-bridge arm lower tube short circuit, the corresponding bridge arm voltage theoretical value is 0, V-phase two driving is all closed, therefore, it is judged whether the sum of two bridge arm midpoint voltages is 0, if 0, it indicates that the vehicle is normally parked, and if not 0, it is considered that the vehicle is slope sliding.

Description

Technical Field

[0001] This invention relates to the field of warehouse vehicle technology, and more specifically to a method for detecting warehouse vehicle runaway on ramps. Background Technology

[0002] Industrial vehicles equipped with wheel-locking brakes will have their wheels locked by electromagnetic brakes after stopping on a slope. To prevent stalling, the motor control will be disabled. When the vehicle is driven again by the accelerator, the electromagnetic brakes will release first, and the vehicle will naturally slide downhill due to its own weight. In applications where warehouse vehicles climb slopes, the accelerator is eventually released, and the motor begins to decelerate. Since there is no speed feedback, the vehicle will roll down the slope before the controller's drive reaches zero and the electromagnetic brakes lock. This is unsafe and provides a poor experience for operators. Therefore, a slope roll detection method is needed to determine if the vehicle is rolling. Existing slope roll detection methods generally require the drive circuit to generate a PWM waveform when the vehicle is stopped to determine if it is rolling. This requires restarting the drive circuit, affecting its state. For example, Chinese patent application number 202111295115.4 discloses a slope roll detection device, detection method, and anti-roll roll system. This invention detects the motor current value and motor bus voltage value using voltage and current detectors, and then combines this with the current motor control signal magnitude to quickly determine if the equipment is rolling. However, this patent requires the drive circuit to generate a PWM waveform when the vehicle is stopped to determine if it is rolling, requiring a restart of the drive circuit, affecting its state.

[0003] Therefore, providing a method for detecting warehouse truck rollover based on the sum of sampled voltages at the midpoint of the bridge arm is a problem worthy of further research. Summary of the Invention

[0004] The purpose of this invention is to provide a method for detecting whether a warehouse vehicle is rolling down a slope by determining whether the vehicle is rolling down a slope based on the sum of the sampled voltages at the midpoint of the bridge arm.

[0005] The objective of this invention is achieved as follows: A method for detecting the slippage of a warehouse vehicle on a ramp includes the following steps: Step 1: After the vehicle stops climbing, the controller controls the U-phase drive motor control signal PWM output to 0 in the DC motor H-bridge circuit, and the V-phase upper and lower tube drives are turned off; for Step 2, the midpoint voltage of the bridge arm is collected. If the vehicle is stationary, the midpoint voltage of the bridge arm is 0. Step 2: The voltage sampler AD samples the voltage information at the midpoint of the bridge arm to make a judgment in step 3; Step 3: Based on the bridge arm midpoint voltage information obtained in Step 2, determine whether the change in bridge arm midpoint voltage is within a reasonable range, and further determine whether the vehicle is in a rollaway state.

[0006] The midpoint voltage of the bridge arm sampled in step 2 is a pulse signal, which is then processed by a low-pass filter.

[0007] In step 3, if the voltage at the midpoint of the bridge arm is greater than the set value, it is determined that the vehicle is in a rolling state; if the voltage at the midpoint of the bridge arm is less than the set value, it is determined that the vehicle is not in a rolling state.

[0008] The beneficial effects of this invention are as follows: Based on the original motor control scheme, this invention controls the output of the motor control signal PWM by controlling the bridge arm drive through the controller. When the output of the U-phase drive is 0, it is equivalent to a short circuit in the lower tube of the U-phase bridge arm, and the theoretical value of the corresponding bridge arm voltage is 0. When both V-phase drives are turned off, the theoretical value of the corresponding bridge arm midpoint voltage is also 0. Therefore, it is determined whether the sum of the midpoint voltages of the two bridge arms is 0. If it is 0, it indicates that the vehicle is normally parked. If it is not 0, it is considered that the vehicle has rolled backwards. Attached Figure Description

[0009] Figure 1 This is a flowchart of the present invention; Figure 2 This is a schematic diagram of the DC motor H-bridge circuit of the present invention; Figure 3 This is a diagram of the DC motor bootstrap drive circuit of the present invention. Detailed Implementation

[0010] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0011] like Figures 1 to 3 As shown, a method for detecting the slippage of a warehouse vehicle on a ramp includes the following steps: Step 1: After the vehicle stops climbing, the controller controls the U-phase drive motor control signal PWM output to 0 in the DC motor H-bridge circuit, and the V-phase upper and lower transistors drive to turn off; the U-phase and V-phase are the H-bridge circuit. We usually say that Q1 / Q2 form the U-phase and Q3 / Q4 form the V-phase. The function of the U-phase and V-phase is to provide a high current loop to drive the motor.

[0012] Step 2: The voltage sampler AD samples the midpoint voltage information of the bridge arm; the sampled midpoint voltage of the bridge arm is a pulse signal, which needs to be processed by a low-pass filter.

[0013] Step 3: Based on the midpoint voltage information of the bridge arm obtained in Step 2, determine whether the voltage change of the bridge arm midpoint is within a reasonable range, and further determine whether the vehicle is in a rolling state. If the midpoint voltage of the bridge arm is greater than the set value, the vehicle is judged to be in a rolling state; if the midpoint voltage of the bridge arm is less than the set value, the vehicle is judged not to be in a rolling state. When the U-phase drive output is 0, it is equivalent to a short circuit in the lower pipe of the U-bridge arm, and the theoretical value of the corresponding bridge arm voltage is 0. When both V-phase drives are turned off, the theoretical value of the corresponding bridge arm midpoint voltage is also 0. Therefore, determine whether the sum of the two bridge arm midpoint voltages is 0. If it is 0, it means that the vehicle is normally parked. If it is not 0, it is considered that the vehicle is rolling.

[0014] Traditional motor control schemes typically involve adding a speed sensor to measure motor speed and determine whether the motor is rotating without a drive. This invention adds an algorithmic control mechanism to the existing H-bridge drive circuit hardware to achieve ramp slip detection.

[0015] This invention, based on the original motor control scheme, uses a controller to control the bridge arm drive to output a PWM motor control signal. When the U-phase drive output is 0, it is equivalent to a short circuit in the lower U-phase bridge arm, corresponding to a theoretical bridge arm voltage of 0. When both V-phase drives are turned off, the theoretical voltage at the midpoint of the corresponding bridge arm is also 0. Therefore, it is determined whether the sum of the voltages at the midpoints of the two bridge arms is 0. If it is 0, it indicates that the vehicle is normally parked. If it is not 0, it is considered that the vehicle has rolled backwards.

Claims

1. A method for detecting the slippage of a warehouse vehicle on a ramp, characterized in that: The steps include: Step 1: After the vehicle stops climbing, the controller controls the U-phase drive motor control signal PWM output to 0 in the DC motor H-bridge circuit, and the V-phase upper and lower transistor drives are turned off; for Step 2, the bridge arm midpoint voltage is collected. If the vehicle is stationary, the bridge arm midpoint voltage is 0. Step 2: The voltage sampler AD samples the midpoint voltage information of the bridge arm to make a judgment in step 3; the midpoint voltage of the bridge arm sampled in step 2 is a pulse signal, which is then processed by a low-pass filter; Step 3: Based on the bridge arm midpoint voltage information obtained in Step 2, determine whether the change in bridge arm midpoint voltage is within a reasonable range, and further determine whether the vehicle is in a rollback state; in Step 3, if the bridge arm midpoint voltage is greater than the set value, it is determined that the vehicle is in a rollback state, and if the bridge arm midpoint voltage is less than the set value, it is determined that the vehicle is not in a rollback state.

Images