Forklift braking performance detection system and method based on laser ranging

Abstract

The invention discloses a forklift braking performance detection system and method based on laser ranging, and the system comprises a reflector, a detection device and a pedal force meter, the detection device comprises a laser displacement sensor and a timing processor, the pedal force meter transmits a brake signal generated by stepping on a brake pedal to the timing processor in a wired manner, and the laser displacement sensor is connected with the timing processor. The timing processor collects high-frequency laser transmitting and receiving signals of the laser displacement sensor in real time and is used for continuously measuring the distance between the forklift and the reflector. And the braking distance, the braking time and the braking deceleration of the forklift are calculated by combining the braking starting time of the forklift transmitted by the pedal force meter and the test set speed of the forklift for stepping on the brake pedal. The brake distance is detected between the laser displacement sensors instead of indirect calculation through other parameters, the measurement precision is high, meanwhile, the brake starting point is obtained in a mechanical triggering mode of the pedal force meter, and therefore the moment when a driver starts the control device is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of forklift braking performance detection, and more specifically, to a forklift braking performance detection system and method based on laser ranging. Background Art

[0002] As a special motor vehicle in the factory, forklift plays an important role in logistics, warehousing and other fields. The braking performance of forklift is directly related to its safety performance, and the braking distance is one of the important indicators for evaluating the braking performance of forklift.

[0003] At present, the common forklift braking distance testers on the market are mainly designed based on the principles of acceleration and deceleration sensors, encoders and GPS. However, in actual testing,

[0004] The braking distance tester based on the GPS principle has the problem that it is difficult to receive satellite signals indoors, and it is easy to fail to measure data under the condition of limited field test distance. At the same time, the test data is basically consistent with the length of the forklift tire brake mark (that is, the stopping distance after the braking effect is produced), which does not meet the test requirements for the field vehicle braking distance test "the distance the vehicle travels from the moment the driver starts to start the control device to the time the vehicle stops".

[0005] The braking distance tester based on the acceleration and deceleration sensor principle has a device that automatically obtains the braking trigger point. Due to the different trigger point acquisition times, the starting points of the braking distance test data are different. At the same time, the pedal-triggered device is easily affected by factors such as road conditions and the vibration of the forklift itself, which makes the braking distance test data vary greatly.

[0006] The braking distance tester based on the encoder principle is more complicated to install. It has higher accuracy in an ideal road test environment. However, due to the small diameter of the encoder wheel in contact with the ground, it is easy to be affected by defects such as unevenness and bumps on the road surface, causing the wheel to lose rotation or abnormal acceleration, thus leading to test data errors.

[0007] Therefore, it is necessary to propose a new solution to detect the braking performance of forklifts. Summary of the invention

[0008] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide a forklift braking performance detection system and method based on laser ranging.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] A forklift braking performance detection system based on laser ranging comprises a reflector located in front of a forklift head, a detection device fixed on the forklift head and matched with the reflector height, and a pedal force meter fixedly mounted on the forklift brake pedal and communicatively connected to the detection device, wherein the reflector is used to provide a laser reflection surface to reflect the high-frequency laser emitted by a laser displacement sensor back to the laser displacement sensor, the detection device comprises a laser displacement sensor and a timing processor, the laser displacement sensor is electrically connected to the timing processor, the timing processor is connected to the pedal force meter via a data line, the pedal force meter transmits the brake signal generated by stepping on the brake pedal to the timing processor by wire, and is used to record and mark the starting time of forklift braking, the timing processor collects the high-frequency laser emission and reception signals of the laser displacement sensor in real time, and is used to continuously measure the distance between the forklift and the reflector, and calculates the braking distance, braking time and braking deceleration of the forklift in combination with the forklift braking starting time transmitted by the pedal force meter and the forklift reaching the test setting speed for stepping on the brake pedal.

[0011] Furthermore, the detection device is communicatively connected to a controller, the controller is used to control the opening and closing of the laser displacement sensor, the controller includes a display screen, and the timing processor displays the measurement data on the display screen.

[0012] Furthermore, the detection device is fixedly mounted on a forklift via a mounting base, the mounting base includes a suction cup and a horizontal adjustment frame connected to the suction cup, the detection device is fixed on the forklift via the suction cup, and the horizontal adjustment frame is used to enable the laser displacement sensor in the detection device to horizontally emit high-frequency laser to the reflective plate.

[0013] Furthermore, the timing processor of the detection device is connected to a handle force meter via a data line, and the handle force meter is used to test the strength of the handbrake handle.

[0014] Furthermore, the detection device includes a shell, the laser displacement sensor is installed on one side of the shell, the timing processor is installed in the shell, the other side of the shell is equipped with an antenna electrically connected to the timing processor, and a communication interface electrically connected to the timing processor, a battery for power supply is also installed in the shell, a charging interface for charging the battery is installed on the other side of the shell, and a circular universal level bubble is installed on the top of the shell.

[0015] The present invention also provides a detection method of a forklift braking performance detection system based on laser ranging, comprising the following steps:

[0016] Step S1, select a straight road section as a road test section, stop the forklift to be tested at one end of the road test section, tie the pedal dynamometer to the brake pedal of the forklift and place it above the brake pedal, fix the detection device on the front of the forklift, and make the high-frequency laser emitted by the laser displacement sensor in the detection device level with the road surface of the road test section, and place a reflector at the other end of the road test section to ensure that the reflector is perpendicular to the road surface of the road test section and faces the laser displacement sensor;

[0017] Step S2, when the forklift starts to move in the same direction as the high-frequency laser emission direction of the laser displacement sensor, the laser displacement sensor is turned on; the forklift continuously moves toward the reflector, and the timing processor collects the high-frequency laser emission and reception signals of the laser displacement sensor in real time, and continuously measures the distance between the forklift and the reflector based on the emission and reception signals;

[0018] Step S3, when the driving speed of the forklift reaches the test set speed, the brake pedal is instantly stepped on to the full state. When the brake pedal is stepped on, the pedal force meter generates a brake signal and transmits it to the timing processor by wire to record and mark the start time of the forklift braking; after the forklift brakes, the timing processor measures that the distance between the forklift and the reflector no longer changes, and records and marks the end time of the forklift braking; the timing processor calculates the forklift braking distance, braking time and braking deceleration based on the distance between the forklift and the reflector before and after the forklift braking, the forklift test set speed, the forklift braking start time and the end time.

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention uses laser displacement sensors to detect the braking distance instead of indirectly calculating through other parameters, with high measurement accuracy. At the same time, the mechanical triggering method of the pedal force meter is used to obtain the braking starting point, thereby obtaining the moment when the driver starts to start the operating device.

[0021] 2. In the present invention, the pedal force meter and the detection device are connected by wired communication instead of wireless transmission, which effectively reduces the delay distance error.

[0022] 3. The present invention minimizes the influence of factors such as uneven road surface and vehicle body vibration during the entire process of vehicle operation from the moment the driver starts to start the operating device to the moment the vehicle stops on the test results. That is, through laser ranging, only the distance between the moment the operating device is started and the moment the vehicle stops is extracted, and there is no need to calculate the stopping distance through the data of the stopping process, thereby avoiding the introduction of other errors.

[0023] 4. In the present invention, the timing processor of the detection device is connected to the handle force meter via a data line. The handbrake handle can be tested for strength by using the handle force meter and the timing processor in combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a structure of a forklift braking performance detection system based on laser ranging in this embodiment;

[0025] Figure 2 This is a schematic diagram of a main structural view of the detection device in this embodiment;

[0026] Figure 3 is a rear view structural schematic diagram of the detection device in this embodiment;

[0027] Figure 4 A schematic diagram of the structure of the mounting base in this embodiment;

[0028] Figure 5 A schematic diagram of a connection structure between a timing processor and a laser displacement sensor in this embodiment;

[0029] Figure 6 Schematic diagram of distance measurement error calculation between the laser displacement sensor and the reflector in this embodiment.

[0030] Figure numerals: reflector 1, detection device 2, laser displacement sensor 201, timing processor 202, housing 203, antenna 204, communication interface 205, battery 206, charging interface 207, circular universal level bubble 208, pedal dynamometer 3, brake pedal 4, forklift 5, controller 6, mounting seat 7, suction cup 701, horizontal adjustment frame 702, handle dynamometer 8, handbrake handle 9. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Embodiment: A forklift braking performance detection system based on laser ranging, such as Figure 1-Figure 5 As shown, it includes a reflector 1 located in front of the front of the forklift 5, a detection device 2 fixed on the front of the forklift 5 and adapted to the height of the reflector 1, and a pedal force meter 3 fixedly installed on the brake pedal 4 of the forklift 5 and communicatively connected with the detection device 2; wherein the reflector 1 is used to provide a laser reflection surface to reflect the high-frequency laser emitted by the laser displacement sensor 201 back to the laser displacement sensor 201.

[0033] like Figure 2 , Figure 3 and Figure 5As shown, the detection device 2 includes a laser displacement sensor 201 and a timing processor 202. The laser displacement sensor 201 is electrically connected to the timing processor 202. The laser displacement sensor 201 includes a laser transmitter and a laser receiver. The laser transmitter is used to emit high-frequency laser, and the laser receiver is used to receive the high-frequency laser reflected by the reflector 1. The timing processor 202 is a processor with a timing function. The timing processor 202 is connected to the pedal dynamometer 3 through a data line, that is, the timing processor 202 and the pedal dynamometer 3 are wired for signal transmission; the pedal dynamometer 3 is a pressure sensor with a strain gauge impedance, and a Wheatstone circuit is formed inside the sensor. The bridge, the sensor will deform when subjected to external force, causing the impedance of the strain gauge close to the internal strain area of ​​the sensor to increase or decrease linearly. The pedal dynamometer 3 transmits the brake signal generated by stepping on the brake pedal 4 to the timing processor 202 by wire, which is used to record and mark the starting time of the forklift 5 braking; the timing processor 202 collects the high-frequency laser emission and reception signals of the laser displacement sensor 201 in real time, which is used to continuously measure the distance between the forklift 5 and the reflector 1, and calculates the braking distance, braking time and braking deceleration of the forklift 5 in combination with the braking starting time of the forklift 5 transmitted by the pedal dynamometer 3 and the test set speed of the forklift 5 for stepping on the brake pedal 4.

[0034] When in use, the braking distance of the forklift 5 is obtained by obtaining the distance traveled by the forklift 5 during the period from the start to the end of the braking of the forklift 5, the braking time of the forklift 5 is obtained by obtaining the time period from the start time to the end time of the braking of the forklift 5, and the deceleration of the forklift 5 is obtained by obtaining the speed of the forklift 5 at the start time of the braking and the braking time of the forklift 5.

[0035] Furthermore, the detection device 2 is communicatively connected to a controller 6, which is used to control the opening and closing of the laser displacement sensor 201. The controller 6 is fixedly installed on the forklift 5. The controller 6 includes a display screen. The timing processor 202 performs graphic simulation based on the measured data and displays the graphics and data on the display screen, such as the braking distance, braking time, braking deceleration, driving speed, test set speed, etc. of the forklift 5.

[0036] Furthermore, the detection device 2 is fixedly mounted on the forklift 5 via the mounting base 7. Figure 4 As shown, the mounting base 7 includes a suction cup 701 and a horizontal adjustment frame 702 connected to the suction cup 701; during installation, the detection device 2 is mounted on the horizontal adjustment frame 702, and the horizontal adjustment frame 702 is fixed on the forklift 5 through the suction cup 701. At the same time, the detection device 2 uses the horizontal adjustment function of the horizontal adjustment frame 702 to make the detection device 2 horizontal, so that the laser displacement sensor 201 can horizontally emit high-frequency laser to the reflector 1. The horizontal adjustment frame 702 can adopt a tripod horizontal adjustment platform of model LP-64, or a universal ball adjustment seat.

[0037] Furthermore, the timing processor 202 of the detection device 2 is connected to the handle force meter 8 via a data line, and the handbrake handle 9 can be tested for strength by using the handle force meter 8 and the timing processor 202 in combination. When in use, the handle force meter 8 is fixed to the handbrake handle 9, and when the handbrake handle 9 is pulled, the handle force meter 8 collects the pulling force of pulling the handbrake handle 9, and transmits the collected data signal to the timing processor 202, and the timing processor 202 displays the pulling force value on the display screen. The handle force meter 8 can use a force sensor of model LM-100, or a micro pressure sensor of model DSHW-108.

[0038] Further, such as Figure 2 and Figure 3 As shown, the detection device 2 includes a shell 203, a laser displacement sensor 201 is installed on one side of the shell 203, a timing processor 202 is installed in the shell 203, and an antenna 204 electrically connected to the timing processor 202 and a communication interface 205 electrically connected to the timing processor 202 are installed on the other side of the shell 203. The communication interface 205 is used to connect the pedal dynamometer 3, the controller 6 and the handle dynamometer 8. A battery 206 for power supply is also installed in the shell 203, and a charging interface 207 for charging the battery 206 is installed on the other side of the shell 203. A circular universal level bubble 208 is installed on the top of the shell 203. The circular universal level bubble 208 can be used to observe whether the detection device 2 is horizontal. At the same time, the circular universal level bubble 208 and the horizontal adjustment frame 702 in the mounting seat 7 are used to adjust the level of the detection device 2.

[0039] The forklift braking performance detection system of this embodiment adopts mechanical triggering (i.e., pedal dynamometer 3) to obtain the braking starting point, thereby obtaining the moment when the driver starts to start the operating device; the pedal dynamometer 3 and the detection device 2 are connected by wired communication instead of wireless transmission, which effectively reduces the delay distance error. Taking the forklift 5 with a maximum operating speed of 20Km / h as an example, its operating speed per second is 5.55m, and the wireless transmission delay is calculated as 100ms, so the delay distance error is 0.55m; the factors such as uneven road surface and vehicle body vibration in the entire process of vehicle operation from the moment when the driver starts to start the operating device to the moment when the vehicle stops have the least impact on the test results, that is, only the distance between the moment when the operating device is started and the moment when the vehicle stops is extracted through laser ranging, and there is no need to calculate the stopping distance through the data of the stopping process (such as acceleration and deceleration, speed, etc.), thereby avoiding the introduction of other errors.

[0040] Under the test conditions of the test site described in 5.1.2 of GB / T 18849-2023, due to the vibration of the vehicle itself or the deviation of the forklift 5, while ensuring that the high-frequency laser can be emitted to the reflector 1, the high-frequency laser is not perpendicular to the reflector 1 when it is emitted to the reflector 1, and there will be a certain angle, resulting in certain data errors during measurement.

[0041] Assume that the vertical distance OP between the laser displacement sensor 201 and the reflector 1 is A, and the size of the reflector 1 is B×B In the most extreme error case, the laser displacement sensor 201 hits the end point O of the reflector 1 to the other end point Q of the reflector 1, and the measured distance is C. Figure 6 shown.

[0042] Error calculation:

[0043]

[0044] When the vertical distance between the laser displacement sensor 201 and the reflector 1 is 10m, and the size of the reflector 1 is 1m×1m, that is, A=10m, B=1m, then:

[0045]

[0046] C=10.1m

[0047] When A=10m, C=10.1m, the error between OP and OQ is 0.1m.

[0048] When the B value remains unchanged (the size of the reflector is fixed) and the A value increases, the α value decreases, and cosα increases (but is less than 1), then the values ​​of A and C become closer, that is, the error becomes smaller. Therefore, when A>10m and B=1m, the maximum error is 0.1m because the laser displacement sensor 201 on the forklift is not emitted vertically to the reflector 1.

[0049] On the premise that the frequency and accuracy of the laser displacement sensor 201 are sufficient, as long as the vertical projection between the laser point and the reflector 1 is ensured and the laser can reach the reflector 1, regardless of the influence of vehicle body vibration or running deviation, the maximum system error when A>10m and B=1m is 0.1m, and the final test data is the difference in distance between the two points of the vehicle and the reflector 1 from the moment the driver starts to start the operating device to the moment the vehicle stops. There will be a difference between the two system errors, that is, the actual measured system error will be smaller than 0.1m, which is acceptable compared to the 1-4m measurement error of the existing rangefinder based on acceleration and deceleration sensors, encoders and GPS principles.

[0050] This embodiment also provides a detection method of a forklift braking performance detection system based on laser ranging, comprising the following steps:

[0051] Step S1, select a straight road section as a road test section, stop the forklift 5 to be tested at one end of the road test section, tie the pedal dynamometer 3 to the brake pedal 4 of the forklift 5 and place it above the brake pedal 4, fix the detection device 2 on the front of the forklift 5, and make the high-frequency laser emitted by the laser displacement sensor 201 in the detection device 2 level with the road surface of the road test section, and place the reflector 1 at the other end of the road test section, ensuring that the reflector 1 is perpendicular to the road surface of the road test section and facing the laser displacement sensor 201;

[0052] Step S2, when the forklift 5 starts to move in the same direction as the high-frequency laser emission direction of the laser displacement sensor 201, the laser displacement sensor 201 is turned on; the forklift 5 continuously moves toward the reflector 1, and the timing processor 202 collects the high-frequency laser emission and reception signals of the laser displacement sensor 201 in real time, and continuously measures the distance between the forklift 5 and the reflector 1 based on the emission and reception signals;

[0053] Step S3, when the travel speed of the forklift 5 reaches the test set speed, the brake pedal 4 is stepped on momentarily until it is fully stepped on. When the brake pedal 4 is stepped on, the pedal force meter 3 generates a brake signal and transmits it to the timing processor 202 via wire to record and mark the start time of the braking of the forklift 5; after the forklift 5 is braked, the timing processor 202 measures that the distance between the forklift 5 and the reflector 1 no longer changes, and records and marks the end time of the braking of the forklift 5; the timing processor 202 calculates the braking distance, braking time and braking deceleration of the forklift 5 based on the distance between the forklift 5 and the reflector 1 before and after the braking of the forklift 5, the test set speed of the forklift 5, and the start and end times of the braking of the forklift 5.

[0054] In step S2, when the laser transmitter in the laser displacement sensor 201 sends out the first pulse signal, timing begins through the timing system of the timing processor 202, and each pulse signal is recorded as a minimum signal travel time from transmission to reception.

[0055] In step S3, when the travel speed of the forklift 5 reaches the test set speed, the forklift 5 can maintain the test set speed and travel a certain distance before the brake pedal 4 is instantly stepped on to the full state; by adopting the above method, the actual speed of the forklift 5 can be obtained and compared with the test set speed for calibration to reduce the error.

[0056] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A forklift braking performance detection system based on laser ranging, characterized in that: The invention comprises a reflective plate (1) located in front of the front of a forklift (5), a detection device (2) fixed to the front of the forklift (5) and matched in height with the reflective plate (1), and a pedal force meter (3) fixedly mounted on a brake pedal (4) of the forklift (5) and communicatively connected to the detection device (2), wherein the reflective plate (1) is used to provide a laser reflection surface to reflect high-frequency laser emitted by a laser displacement sensor (201) back to the laser displacement sensor (201), and the detection device (2) comprises a laser displacement sensor (201) and a timing processor (202), wherein the laser displacement sensor (201) is electrically connected to the timing processor (202), and the timing processor (202) is electrically connected to the laser displacement sensor (201). The device (202) is connected to the pedal force meter (3) via a data line. The pedal force meter (3) transmits the brake signal generated by stepping on the brake pedal (4) to the timing processor (202) via a wire, so as to record and mark the starting time of braking of the forklift (5). The timing processor (202) collects high-frequency laser emission and reception signals of the laser displacement sensor (201) in real time, so as to continuously measure the distance between the forklift (5) and the reflector (1), and calculates the braking distance, braking time and braking deceleration of the forklift (5) in combination with the braking starting time of the forklift (5) transmitted from the pedal force meter (3) and the test set speed of the forklift (5) when stepping on the brake pedal (4).

2. According to claim 1, a forklift braking performance detection system based on laser ranging is characterized in that: The detection device (2) is communicatively connected to a controller (6), the controller (6) is used to control the opening and closing of the laser displacement sensor (201), the controller (6) comprises a display screen, and the timing processor (202) displays the measurement data on the display screen.

3. According to claim 1, a forklift braking performance detection system based on laser ranging is characterized in that: The detection device (2) is fixedly mounted on a forklift (5) via a mounting seat (7); the mounting seat (7) comprises a suction cup (701) and a horizontal adjustment frame (702) connected to the suction cup (701); the detection device (2) is fixed on the forklift (5) via the suction cup (701), and the horizontal adjustment frame (702) enables a laser displacement sensor (201) in the detection device (2) to horizontally emit high-frequency laser light to a reflective plate (1).

4. According to claim 1, a forklift braking performance detection system based on laser ranging is characterized in that: The timing processor (202) of the detection device (2) is connected to a handle force meter (8) via a data line, and the handle force meter (8) is used to perform a force test on a handbrake handle (9).

5. According to claim 1, a forklift braking performance detection system based on laser ranging is characterized in that: The detection device (2) comprises a housing (203), the laser displacement sensor (201) is mounted on one side of the housing (203), the timing processor (202) is mounted in the housing (203), an antenna (204) electrically connected to the timing processor (202) and a communication interface (205) electrically connected to the timing processor (202) are mounted on the other side of the housing (203), a battery (206) for power supply is also mounted in the housing (203), a charging interface (207) for charging the battery (206) is mounted on the other side of the housing (203), and a circular universal level bubble (208) is mounted on the top of the housing (203).

6. A detection method of a forklift braking performance detection system based on laser ranging according to any one of claims 1 to 5, characterized in that: The steps include: Step S1, selecting a straight road section as a road test section, stopping the forklift (5) to be tested at one end of the road test section, fastening the pedal dynamometer (3) to the brake pedal (4) of the forklift (5) and locating it above the brake pedal (4), fixing the detection device (2) on the front of the forklift (5), and making the high-frequency laser emitted by the laser displacement sensor (201) in the detection device (2) level with the road surface of the road test section, placing the reflector (1) at the other end of the road test section, ensuring that the reflector (1) is perpendicular to the road surface of the road test section and facing the laser displacement sensor (201); Step S2, when the forklift (5) starts to move in the same direction as the high-frequency laser emission direction of the laser displacement sensor (201), the laser displacement sensor (201) is turned on; the forklift (5) continuously moves toward the reflective plate (1), and the timing processor (202) collects the high-frequency laser emission and reception signals of the laser displacement sensor (201) in real time, and continuously measures the distance between the forklift (5) and the reflective plate (1) based on the emission and reception signals; Step S3, when the travel speed of the forklift (5) reaches the test set speed, the brake pedal (4) is instantly stepped on to the fully stepped state. When the brake pedal (4) is stepped on, the pedal force meter (3) generates a brake signal and transmits it to the timing processor (202) via wire to record and mark the start time of the braking of the forklift (5); after the forklift (5) is braked, the timing processor (202) measures that the distance between the forklift (5) and the reflector (1) no longer changes, and records and marks the end time of the braking of the forklift (5); the timing processor (202) calculates the braking distance, braking time and braking deceleration of the forklift (5) based on the distance between the forklift (5) and the reflector (1) before and after the braking of the forklift (5), the test set speed of the forklift (5), the start time and the end time of the braking of the forklift (5).

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