Test method for maximum braking distance of electrically driven fork truck on road

Abstract

The application discloses a kind of electric drive fork truck road test maximum braking distance test method, comprising: wireless current clamp is equipped on the battery or motor power cable of electric drive fork truck, laser radar and industrial computer are laid on test path, industrial computer is connected with wireless current clamp, laser radar communication;Electric drive fork truck is accelerated to maximum stable speed, keeps uniform speed and enters the detection area of laser radar;Braking starting point A is selected in detection area, test driver releases acceleration pedal and immediately steps on brake pedal at A point, and wireless current clamp detects motor power current sudden drop and sends signal to industrial computer;Industrial computer calibrates with the vehicle position corresponding to current sudden drop time as braking starting point A starts, laser radar continuously detects vehicle position, until vehicle stops at braking termination point B;Industrial computer determines as the maximum braking distance s1 of electric drive fork truck according to the distance of A point to B point measured by laser radar, solve the problem that braking starting point is difficult to accurately position.

Description

Technical Field

[0001] This invention relates to the field of forklift technology, and more specifically, to a test method for the maximum braking distance of an electric forklift during road testing. Background Technology

[0002] Therefore, how to provide a test method for the maximum braking distance of an electric forklift during road testing has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0003] The purpose of this invention is to provide a new technical solution for testing the maximum braking distance of an electric forklift during road testing.

[0004] According to a first aspect of the present invention, a method for testing the maximum braking distance of an electrically driven forklift during road testing is provided, comprising the following steps:

[0005] The wireless current clamp is attached to the battery or motor power cable of the electric drive forklift. A lidar and an industrial control computer are deployed along the test path. The industrial control computer is communicatively connected to the wireless current clamp and the lidar.

[0006] Accelerate the electric forklift to its maximum stable speed and maintain a constant speed as it enters the detection area of ​​the lidar.

[0007] Select braking start point A within the testing area. The test driver releases the accelerator pedal at point A and immediately depresses the brake pedal. The wireless current clamp detects a sudden drop in the motor power supply current and sends a signal to the industrial control computer.

[0008] The industrial control computer starts calibration with the vehicle position corresponding to the moment of current drop as the braking start point A. The lidar continuously detects the vehicle position until the vehicle stops at the braking end point B.

[0009] The industrial control computer determines the maximum braking distance s1 of the electric forklift based on the distance from point A to point B measured by the lidar.

[0010] Optionally, the current drop is as follows: after releasing the accelerator pedal, the motor controller stops power output, and a small current is generated in the cable by the back EMF of the motor, causing the current value detected by the wireless current clamp to drop sharply.

[0011] Optionally, the distance between the braking starting point A and the vertical position of the lidar is half of the maximum braking distance s1.

[0012] Optionally, the industrial control computer has a built-in signal receiver that communicates with the wireless current clamp in real time. When it receives a current drop signal, it immediately triggers position timing and distance measurement.

[0013] Optionally, the linear detection range of the lidar is s2, and the braking start point A to the braking end point B are within the range of s2.

[0014] Optionally, the wireless current clamp wirelessly transmits the current drop signal to the industrial control computer in real time.

[0015] Optionally, the lidar collects vehicle position data in real time and uploads it to the industrial control computer, which calculates the braking distance s1 based on the position difference.

[0016] Optionally, the maximum stable speed is the highest permissible driving speed for the electric drive forklift during road testing, and it has maintained a constant speed before entering the lidar detection area.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention uses a sudden drop in motor power supply current as the braking initiation trigger signal, replacing traditional methods such as manual timing and brake mark judgment, completely solving the problem of difficult precise positioning of the braking start point, and ensuring no subjective deviation in the test start point; it also adopts non-contact ranging with lidar, combined with precise triggering of current sudden change, and fully automated data acquisition and calculation, avoiding errors caused by manual measurement and mark interpretation, and the braking distance value is objective and accurate, meeting the requirements for road test performance evaluation.

[0019] This invention can be deployed with just wireless current clamps, lidar, and an industrial computer, without the need for complex vehicle and site modifications. It is easy for test drivers to operate, and braking distance tests can be completed simultaneously during road tests without adding a lot of extra procedures. Moreover, it does not rely on brake force testing and is specifically designed for electric drive forklifts that can only be road tested and whose braking force values ​​cannot be measured. It has a wider range of applications and solves the industry pain point that the braking performance of such models cannot be accurately evaluated.

[0020] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0022] Figure 1 This is a flowchart of the test method for the maximum braking distance of the electric drive forklift during road testing according to the present invention;

[0023] Figure 2 This is a schematic diagram of the test method for the maximum braking distance of the electric drive forklift during road testing according to the present invention.

[0024] The diagram is labeled as follows: 1. Wireless current clamp; 2. Vehicle; 3. LiDAR; CD, radar detection area; AB, vehicle braking area; s1, braking distance; s2, radar detection distance. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0026] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0027] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0028] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0029] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a test method for the maximum braking distance of an electric forklift during road testing, including the following steps:

[0030] The wireless current clamp 1 is clamped onto the battery or motor power supply cable of the electric drive forklift. The lidar 3 and the industrial control computer are deployed on the test path. The industrial control computer is communicatively connected to the wireless current clamp 1 and the lidar 3.

[0031] Accelerate the electric forklift to its maximum stable speed and maintain a constant speed as it enters the detection area of ​​the lidar 3;

[0032] Select braking start point A within the detection area. The test driver releases the accelerator pedal at point A and immediately depresses the brake pedal. Wireless current clamp 1 detects a sudden drop in motor power supply current and sends a signal to the industrial control computer.

[0033] The industrial control computer starts calibration with the position of vehicle 2 corresponding to the moment of current drop as the braking start point A. The lidar 3 continuously detects the position of vehicle 2 until vehicle 2 stops at the braking end point B.

[0034] The industrial control computer determines the maximum braking distance s1 of the electric forklift based on the distance from point A to point B measured by the lidar 3.

[0035] This invention uses a wireless current clamp 1 to detect a sudden drop in the motor power supply current as the braking start point trigger signal, accurately capturing the braking start moment and completely solving the technical problems of inaccurate determination of the starting point of traditional manual timing and brake mark determination. It eliminates human error at the source and significantly improves the test accuracy.

[0036] This invention achieves fully automated braking distance detection through non-contact ranging with LiDAR and automatic calculation by an industrial control computer. It eliminates the need for manual measurement and reading, providing objective, stable, and highly repeatable test data that accurately obtains the maximum braking distance during road tests of electric forklifts. Furthermore, it eliminates the need to measure brake force, making it specifically designed for electric forklifts where brake force testing is not feasible. This broadens its applicability and meets the braking performance testing needs of vehicles designed only for road testing, demonstrating strong versatility.

[0037] The testing device of this invention is easy to install and operate, requires no modification to the forklift, does not damage the vehicle's circuitry and structure, and can simultaneously complete braking distance testing during routine road tests. The process is simple, efficient, and suitable for batch use on site.

[0038] This invention is tested under actual road test conditions. The braking operation and driving state closely match the real-world usage scenario of vehicle 2. The test results can accurately reflect the actual braking performance of the electric drive forklift and have greater engineering reference value. The wireless current clamp 1 communicates with the industrial control computer in real time with no delay triggering and accurate timing matching, avoiding ranging deviations caused by signal lag and further ensuring the reliability of the test results.

[0039] In one embodiment of the test method for the maximum braking distance of the electric drive forklift road test, the sudden drop in current is as follows: after releasing the accelerator pedal, the motor controller stops power output, and a small current is generated in the cable by the back electromotive force of the motor, causing the wireless current clamp 1 to detect a sharp drop in current value.

[0040] The current drop occurs the instant the accelerator pedal is released, corresponding in real-time to the braking pedal being depressed. There is no mechanical lag, transmission delay, or recognition delay, allowing for precise pinpointing of the braking initiation moment. This avoids issues like excessively long braking distances and inaccurate data caused by trigger lag. The current drop signal is directly generated by the motor power supply circuit and is unaffected by external conditions such as light, road surface, dust, vehicle speed, and tire tracks. It can be stably identified indoors and outdoors, on different road surfaces, and under different load conditions, demonstrating strong applicability and a low false trigger rate.

[0041] In one embodiment of the test method for the maximum braking distance of the electric drive forklift road test, the distance between the braking starting point A and the vertical position of the lidar 3 is half of the maximum braking distance s1.

[0042] Specifically, the central area of ​​lidar 3 has the highest ranging accuracy, while the edge areas are prone to angular deviations, signal attenuation, and measurement errors. Placing the entire braking process at the detection center ensures that the position acquisition of vehicle 2 from the start of braking to its stop is within the optimal measurement range, effectively reducing the measurement error of the lidar itself. Arranging braking start points A with the vertical point of lidar 3 as the center and s1 / 2 in front and behind ensures that the entire braking process AB falls completely within the effective detection range of the lidar, preventing data interruptions and position loss due to the start or end point exceeding the detection area, ensuring a continuous and reliable testing process.

[0043] Furthermore, when measuring at long distances at an oblique angle, the lidar 3 is prone to angular distortion and projection errors. By centering the braking area, the vehicle 2 and the lidar can always maintain an optimal observation posture that is close to perpendicular, which greatly reduces the calculation deviation caused by geometric distortion and improves the accuracy of braking distance.

[0044] In one embodiment of the test method for the maximum braking distance of the electric drive forklift road test, the industrial control computer has a built-in signal receiver that communicates with the wireless current clamp 1 in real time. When it receives a current drop signal, it immediately triggers position timing and distance measurement.

[0045] Specifically, the wireless current clamp 1 communicates with the industrial control computer in real time through a built-in receiver. The current drop signal is received instantly as soon as it is generated, with no transmission lag or processing delay, ensuring that the braking start time and the distance measurement start time are strictly synchronized, thus avoiding the braking distance test being too large and the data being distorted due to signal delay.

[0046] The signal receiver is integrated into the industrial control computer, eliminating the need for additional external modules and complex wiring. The overall test system features streamlined hardware, reliable connections, and high efficiency for on-site installation and debugging, making it suitable for rapid use in road test sites.

[0047] In one embodiment of the test method for the maximum braking distance of the invented electric drive forklift during road testing, such as Figure 2 As shown, CD is the radar detection area, AB is the braking area of ​​vehicle 2, the straight-line detection distance of lidar 3 is s2, and the braking start point A to the braking end point B are within the range of s2.

[0048] This invention ensures that the entire braking distance AB is strictly limited within the linear detection distance s2 of the lidar 3, guaranteeing that the entire displacement segment of the vehicle 2 from the start of braking to complete stop is continuously and completely within the effective detection range of the lidar. This avoids the loss of termination point data or incomplete conditions where only a partial braking trajectory can be collected due to the vehicle 2 leaving the effective range of the lidar, thus ensuring a closed loop of braking distance test data.

[0049] The lidar 3 achieves the highest accuracy in the central region of the detection range, while signal attenuation, angular measurement errors, or geometric distortion are prone to occur near the edges. This invention encompasses the entire braking stroke within the s2 range, meaning that the entire process of vehicle 2 starting at braking point A and stopping at braking point B is within the radar's optimal operating range of high signal-to-noise ratio and low distortion rate. This minimizes the inherent measurement errors of the radar itself, directly improving the accuracy of the final calculated braking distance s2.

[0050] Furthermore, during actual road tests, the test driver may have slight deviations in controlling the braking initiation point A, or fluctuations in the vehicle's load or the road surface friction coefficient may occur, potentially leading to an actual braking distance slightly longer than predicted. Limiting the entire braking distance from initiation point A to termination point B within s2 provides ample redundancy design margin. Even with minor fluctuations in operating conditions, it ensures that vehicle 2 remains within radar visibility, preventing test failure due to sudden overtravel and significantly improving the test method's fault tolerance and stability.

[0051] In one embodiment of the test method for the maximum braking distance of the electric drive forklift road test, the wireless current clamp 1 wirelessly transmits the current drop signal to the industrial control computer in real time.

[0052] Specifically, wireless transmission eliminates the need for communication cables between the forklift and the industrial control computer, making installation quick and easy, and allowing for rapid adaptation to different vehicle models and test sites, significantly improving road test efficiency. The current drop signal is instantly uploaded wirelessly upon generation, eliminating cable transmission delays and mechanical lag, ensuring strict synchronization between the braking start and distance measurement trigger moments, thus preventing overestimation of braking distance due to signal lag.

[0053] In one embodiment of the test method for the maximum braking distance of the electric drive forklift road test, the lidar 3 collects the position data of the vehicle 2 in real time and uploads it to the industrial control computer. The industrial control computer calculates the braking distance s1 through the position difference.

[0054] Specifically, the lidar 3 continuously and at high frequency collects the position of the vehicle 2, fully covering the entire process from the start of braking to complete stop, without any sampling interruption or missed position measurement, ensuring that the braking distance calculation is based on complete and accurate data.

[0055] In one embodiment of the test method for the maximum braking distance of the electric drive forklift during road testing, the maximum stable speed is the highest permissible driving speed of the electric drive forklift during road testing, and it has maintained a constant speed before entering the detection area of ​​the lidar 3.

[0056] Specifically, under constant speed conditions, Vehicle 2 exhibits smooth power output, and the current drop signal upon releasing the accelerator pedal is clearer and more standardized, preventing triggering misjudgments caused by current fluctuations during acceleration. This results in more accurate braking initiation point determination and more reliable system response. Testing was conducted at the highest permissible constant speed during road testing, fully reflecting actual operating conditions. The measured braking distance can be directly used for vehicle 2 safety assessment, standard compliance determination, and product design improvement, providing more practical guidance.

[0057] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A test method for the maximum braking distance of an electric forklift during road testing, characterized in that, Includes the following steps: The wireless current clamp is attached to the battery or motor power cable of the electric drive forklift. A lidar and an industrial control computer are deployed along the test path. The industrial control computer is communicatively connected to the wireless current clamp and the lidar. Accelerate the electric forklift to its maximum stable speed and maintain a constant speed as it enters the detection area of ​​the lidar. Select braking start point A within the testing area. The test driver releases the accelerator pedal at point A and immediately depresses the brake pedal. The wireless current clamp detects a sudden drop in the motor power supply current and sends a signal to the industrial control computer. The industrial control computer starts calibration with the vehicle position corresponding to the moment of current drop as the braking start point A. The lidar continuously detects the vehicle position until the vehicle stops at the braking end point B. The industrial control computer determines the maximum braking distance s1 of the electric forklift based on the distance from point A to point B measured by the lidar.

2. The test method for the maximum braking distance of an electric drive forklift during road testing according to claim 1, characterized in that, The sudden drop in current is as follows: after releasing the accelerator pedal, the motor controller stops power output, and a small current is generated in the cable by the back EMF of the motor, causing the current value detected by the wireless current clamp to drop sharply.

3. The test method for the maximum braking distance of an electric drive forklift during road testing according to claim 1, characterized in that, The distance between the braking starting point A and the vertical position of the lidar is half of the maximum braking distance s1.

4. The test method for the maximum braking distance of an electric drive forklift during road testing according to claim 1, characterized in that, The industrial control computer has a built-in signal receiver that communicates with the wireless current clamp in real time. When it receives a sudden drop in current signal, it immediately triggers position timing and distance measurement.

5. The test method for the maximum braking distance of an electric drive forklift during road testing according to claim 1, characterized in that, The linear detection range of the lidar is s2, and the braking start point A to the braking end point B are within the range of s2.

6. The test method for the maximum braking distance of an electric drive forklift during road testing according to claim 1, characterized in that, The wireless current clamp transmits the current drop signal to the industrial control computer in real time wirelessly.

7. The test method for the maximum braking distance of an electric drive forklift during road testing according to claim 1, characterized in that, The lidar collects vehicle position data in real time and uploads it to the industrial control computer. The industrial control computer calculates the braking distance s1 based on the position difference.

8. The test method for the maximum braking distance of an electric drive forklift during road testing according to claim 1, characterized in that, The maximum stable speed is the highest permissible driving speed for the electric drive forklift during road testing, and it has maintained a constant speed before entering the lidar detection area.

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