System and method for testing torsion wire harness performance of electric pallet truck

Abstract

The invention discloses an electric pallet truck torsion wire harness performance test system and method. The test system comprises a first torsion wire harness connected between the output end of a controller and the input ends of a handle and an interlocking switch, and a second torsion wire harness connected between the output end of the controller and the input ends of a traction motor and an electromagnetic brake; the first torsion wire harness and the second torsion wire harness are respectively connected with a test wire harness, and the test wire harnesses are connected with a function indication box; the function indication box comprises a buzzer and a plurality of groups of detection units consisting of optical couplers and relays; in each detection unit, the optocoupler is connected with the controller, and the relay is connected with the buzzer. According to the invention, two torsion wire harnesses with more serious rotation frequency and wear degree are respectively connected with a test wire harness, and are respectively connected with a controller through a function indication box; whether the twisted wire harness is good or not is judged by observing whether the light-emitting diode in the function indication box emits light or not, and meanwhile a buzzer gives an alarm for reminding.

Description

Technical Field

[0001] The invention relates to the field of electric pallet trucks, and in particular to a system and method for testing the torsion harness performance of an electric pallet truck. Background Art

[0002] Electric pallet trucks are widely used in various logistics, warehousing and transportation fields due to their small size, lightweight design and easy operation. In the design of the control system of electric pallet trucks, a system architecture based on controller signals directly input by analog quantity and switch is currently widely used. Compared with the design that uses CAN communication scheme for input instructions and controller signal reception, this design method has the advantages of lower cost and simpler and more intuitive troubleshooting process. However, this design also faces a significant problem, that is, there are too many internal connecting wires in the vehicle, which increases the complexity of the system.

[0003] In an electric pallet truck, the body harness refers to an assembly consisting of multiple wires, terminals, connectors and other components, which is used to connect key components such as handles, switches, motor sensors, and controllers into a complete circuit system. It is an important part of the electrical system of an electric pallet truck, responsible for transmitting electrical energy, control signals, and sensor signals, etc., to ensure smooth communication between various devices, thereby achieving normal operation of the vehicle. During the assembly process of the body harness, the signal line, power line, etc. of the controller need to pass through the handle connecting rod to connect with the handle. When the handle drives the drive unit to rotate, the body harness connected to the controller will also rotate accordingly. Especially during the turning and operation of the vehicle, the handle needs to be frequently pressed and rotated, which further aggravates the rotation frequency and wear degree of the body harness. Among them, there are two torsion harnesses with more serious rotation frequency and wear degree, of which the first torsion harness 9-1 is the connection line between the handle 2 and the interlock switch 14 installed on the handle bracket and the controller 1 respectively, and the second torsion harness 9-2 is the connection line between the traction motor 3 and the electromagnetic brake 16 installed on the traction motor drive shaft and the controller 1 respectively (see for details). Figure 1 shown).

[0004] Therefore, in the new product design stage, the selection of wires in the body harness and reliability testing have become an indispensable and important testing link before the vehicle is scheduled for production. However, due to the limitations of the analog quantity and switch input design system commonly used in current electric pallet trucks, even if the wires in the body harness are broken during the use of the vehicle, the system cannot determine whether there is analog quantity and switch operation command input at this time, and cannot issue an alarm signal in time, making it difficult to accurately determine the wire specifications selected for the body harness, the rationality of the manufacturing process, and its effective service life. This problem poses a potential challenge to improving the overall performance and reliability of electric pallet trucks. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a testing system and method for the torsion harness performance of an electric pallet truck, so as to detect and judge the performance of the vehicle body harness in real time.

[0006] The specific technical solutions of the present invention are as follows:

[0007] The first inventive object of the present invention is to provide a testing system for the torsion harness performance of an electric pallet truck, comprising a first torsion harness connected between the output end of a controller and the handle and the input end of an interlock switch, and a second torsion harness connected between the output end of the controller and the input end of a traction motor and an electromagnetic brake; the first torsion harness and the second torsion harness are respectively connected to a test harness, and the test harness is connected to a function indicator box; the function indicator box comprises a buzzer and a plurality of detection units composed of optical couplers and relays; in each detection unit, the optical coupler is connected to the controller, and the relay is connected to the buzzer.

[0008] In a further solution, the optocoupler includes a phototransistor and a light-emitting diode, the phototransistor is connected to the coil of the relay, and the contacts of the relay are connected to the buzzer; the relay is a normally closed relay, when the light-emitting diode is energized and emits light, the coil of the relay is energized and the contacts are disconnected, and the buzzer circuit is disconnected; when the light-emitting diode is powered off and extinguished, the coil of the relay loses power and the contacts are connected, and the buzzer circuit is connected and an alarm is sounded.

[0009] In a further solution, the traction motor includes a speed sensor and a temperature sensor;

[0010] The second torsion harness is connected to the second function indicator box through the second test harness. The second function indicator box includes 8 groups of detection units, among which 5 groups of detection units have one end connected to the controller and the other end connected to the speed sensor; 2 groups of detection units have one end connected to the controller and the other end connected to the temperature sensor; 1 group of detection units has one end connected to the controller and the other end connected to the controller through an electromagnetic brake.

[0011] In a further embodiment, the handle includes a key switch connected to a battery pack, an output end of the key switch is connected to a switch circuit board, and a lifting switch, a lowering switch, an accelerator, a reverse switch, an emergency reverse switch, and a horn switch are installed on the switch circuit board;

[0012] The first torsion harness is connected to the first function indicator box through the first test harness, and the first function indicator box includes 8 groups of detection units, among which one end of the first group of detection units is connected to the controller, and the other end is connected to the key switch; one end of the second group of detection units is connected to the controller through the coil of the lifting contactor, and the other end is connected to the lifting switch, and the contacts of the lifting contactor are connected in series between the battery pack and the lifting motor; one end of the third group of detection units is connected to the controller through the descending solenoid valve, and the other end is connected to the descending switch; one end of the fourth group of detection units is connected to the controller, and the other end is connected to the accelerator; one end of the fifth group of detection units is connected to the controller, and the other end is connected to the reverse switch; one end of the sixth group of detection units is connected to the controller, and the other end is connected to the emergency reverse switch; one end of the seventh group of detection units is connected to the controller through the interlocking switch; one end of the eighth group of detection units is connected to the horn switch, and the other end is connected to the horn.

[0013] In a further solution, the power port of the function indicator box is connected to the vehicle control power supply for power supply;

[0014] The controller and the handle are connected in series at both ends of the battery pack, respectively. A second fuse is connected between the positive end of the battery pack and the controller; a first fuse and an emergency power-off switch are connected in sequence between the positive end of the battery pack and the handle.

[0015] The second invention object of the present invention is to provide a method for testing the torsion harness performance of an electric pallet truck, which comprises the following steps:

[0016] S1, connect the first test harness to the first torsion harness connected between the output end of the controller and the handle and the input end of the interlock switch, then connect the first test harness to the first function indicator box, and the first function indicator box to the controller;

[0017] Connecting a second test harness to a second torsion harness connected between an output end of the controller and an input end of the traction motor and an electromagnetic brake, and then connecting the second test harness to a second function indicator box, and the second function indicator box is connected to the traction motor;

[0018] S2, turn on the power, close the key switch in the handle, and the controller and the switch circuit board in the handle are powered on for self-test, and at the same time, power is provided to the optocouplers in the first function indicator box and the second function indicator box;

[0019] S3. After closing the key switch, operate the lifting switch, lowering switch, interlock switch, accelerator, reverse switch, emergency reverse switch and horn switch in sequence to check whether the light-emitting diodes in the first optical couplers in the first function indicator box are lit; if all of them are lit, it indicates that the performance of the first torsion harness is good; if one of the light-emitting diodes is off, the wire package of the corresponding relay loses power and the contact is connected, and the first buzzer circuit is connected to alarm, indicating that the first torsion harness is open circuit;

[0020] S4. Check whether the light-emitting diodes in each second optocoupler in the second function indicator box are lit. If all of them are lit, it indicates that the performance of the second torsion harness is good. If one of the light-emitting diodes is off, the corresponding relay coil loses power and the contacts are connected, and the second buzzer circuit is connected and an alarm is sounded, indicating that the second torsion harness is open.

[0021] In a further solution, in step S1, the first function indicator box includes 8 sets of detection units, and the detection units include a first optical coupler and a first relay;

[0022] One end of the first group of detection units is connected to the controller, and the other end is connected to the key switch; one end of the second group of detection units is connected to the controller through the coil of the lifting contactor, and the other end is connected to the lifting switch, and the contacts of the lifting contactor are connected in series between the battery pack and the lifting motor; one end of the third group of detection units is connected to the controller through the descending solenoid valve, and the other end is connected to the descending switch; one end of the fourth group of detection units is connected to the controller, and the other end is connected to the accelerator; one end of the fifth group of detection units is connected to the controller, and the other end is connected to the reverse switch; one end of the sixth group of detection units is connected to the controller, and the other end is connected to the emergency reverse switch; one end of the seventh group of detection units is connected to the controller through the interlocking switch; one end of the eighth group of detection units is connected to the horn switch, and the other end is connected to the horn.

[0023] In a further solution, in step S1, the traction motor includes a speed sensor and a temperature sensor;

[0024] The second function indicator box includes 8 groups of detection units, and the detection units include a second optical coupler and a second relay;

[0025] Among them, one end of 5 groups of detection units are connected to the controller, and the other end is connected to the speed sensor; one end of 2 groups of detection units are connected to the controller, and the other end is connected to the temperature sensor; one end of 1 group of detection units is connected to the controller, and the other end is connected to the controller through an electromagnetic brake.

[0026] In a further solution, in step S3, the specific steps are as follows:

[0027] S31, close the key switch, when the performance of the first torsion harness is good, the light-emitting diode of the first optical coupler in the first function indicator box is powered on and emits light, the coil of the relay is powered on and the contact is disconnected, and the first buzzer circuit is disconnected; when the light-emitting diode is powered off and extinguished, the coil of the relay loses power and the contact is connected, and the first buzzer circuit is connected and an alarm is sounded, indicating that the first torsion harness connected here is open circuit;

[0028] S32, after closing the key switch, when the lifting switch is closed again, the first optical coupler 2 in the first function indicator box and the lifting contactor wire package are energized, so that the contact of the lifting contactor is connected, and the lifting motor works to drive the fork to rise; if the light-emitting diode in the first optical coupler 2 is lit, it indicates that the performance of the first torsion harness is good; when the light-emitting diode in the first optical coupler 2 is off, the relay wire package loses power and the contact is connected, and the first buzzer circuit is connected and an alarm is sounded; indicating that the first torsion harness connected here is open circuit;

[0029] S33, after closing the key switch in the handle, when the descending switch is closed again, the first optical coupler 3 in the first function indicator box and the descending relay are energized, the descending relay opens the oil return path of the descending cylinder, and the fork descends; if the light-emitting diode in the first optical coupler 3 is lit, it indicates that the performance of the first torsion harness is good; when the light-emitting diode in the first optical coupler 3 is off, the relay wire package loses power and the contact is connected, and the first buzzer circuit is connected to alarm; indicating that the first torsion harness connected here is open circuit;

[0030] S34, after closing the key switch in the handle, and then closing the interlock switch, the light-emitting diode in the first optocoupler in the first function indicator box is energized and emits light; when the light-emitting diode in the first optocoupler is extinguished, the wire package of the relay loses power and the contact is connected, and the first buzzer circuit is connected and an alarm is sounded, indicating that the first torsion wire harness connected here is open circuit;

[0031] S35, after closing the key switch and the interlock switch, rotate the accelerator in the handle backward, close the reverse switch, the light-emitting diodes in the first optical coupler 4 and the first optical coupler 5 are energized and emit light, and control the vehicle to run in the reverse direction; if the first optical coupler 4 or the first optical coupler 5 is off, the relay wire package loses power and the contact is connected, and the first buzzer circuit is connected to alarm, indicating that the first torsion harness connected here is open circuit;

[0032] S36, after closing the key switch and the interlock switch, the emergency reverse switch is closed, and the six light-emitting diodes in the first optocoupler are all energized and illuminated, and the controller controls the traction motor to run in an emergency reverse direction; if the six light-emitting diodes in the first optocoupler are extinguished, the coil of the relay loses power and the contact is connected, and the first buzzer circuit is connected and an alarm is sounded, indicating that the first torsion harness connected here is open circuit;

[0033] S37. After closing the key switch in the handle, close the horn switch, the eight light-emitting diodes in the first optocoupler are all powered on and illuminated, and the horn works; if the eight light-emitting diodes in the first optocoupler are off, the relay coil loses power and the contacts are connected, and the first buzzer circuit is connected and an alarm is sounded, indicating that the first torsion harness connected here is open-circuited.

[0034] The present invention adopts the method of connecting a test harness to each port on a function indicator box respectively on two torsion harnesses where the rotation frequency and the wear degree are more serious, and then connecting the function indicator box to the controller; then observing whether the light-emitting diodes in the function indicator box are lit; if all of them are lit, it indicates that the performance of the torsion harness is good; if one of the light-emitting diodes is off, the coil of the relay connected to the light-emitting diode loses power and the contact is connected, thereby connecting the buzzer circuit and alarming; indicating that the torsion harness is open-circuited, its performance does not meet the requirements, and needs to be reselected.

[0035] The wires of each twisted part of the vehicle harness are connected to the function indicator box through the test harness to detect the on / off status of each wire. In the vehicle harness reliability test, when any wire in the vehicle harness test part is broken, when the analog quantity and switch operation command are triggered, the function indicator box will emit a buzzer and the LED will go out to indicate that the vehicle harness is broken.

[0036] Therefore, the present invention aims at the limitations of the analog quantity and switch input design system commonly used in current electric pallet trucks. When the wires in the body wiring harness are broken during the use of the vehicle, the wire specifications selected for the body wiring harness, the rationality of the manufacturing process and its effective service life can be intuitively judged by whether the light-emitting diode is lit and the buzzer is alarmed. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a structural diagram of the electric pallet truck in the present invention;

[0038] Figure 2 This is a principle block diagram of the present invention.

[0039] Figure 3 This is a circuit diagram of the present invention.

[0040] In the figure: controller 1, handle 2, key switch 21, lifting switch 22, lowering switch 23, accelerator 24, reverse switch 25, emergency reverse switch 26, horn switch 27,

[0041] Traction motor 3, speed sensor 31, temperature sensor 32;

[0042] A first test harness 4, a second test harness 5, a first function indicator box 6, a second function indicator box 7, a battery pack 8, a vehicle body harness 9, a first torsion harness 91, a second torsion harness 92, an emergency power-off switch 10, a lifting motor 11, a lifting contactor 12, a lowering solenoid valve 13, an interlock switch 14, a horn 15, an electromagnetic brake 16, a first fuse 17, and a second fuse 18;

[0043] Wherein: in the first function indicator box 6:

[0044] first optical coupler 1 611, first optical coupler 2 612, first optical coupler 3 613, first optical coupler 4 614, first optical coupler 5 615, first optical coupler 616, first optical coupler 7 617, first optical coupler 8 618,

[0045] first relay 1 621, first relay 2 622, first relay 3 623, first relay 4 624, first relay 5 625, first relay 6 626, first relay 7 627, first relay 8 628,

[0046] First buzzer 63;

[0047] In the second function indicator box 7:

[0048] The second optical coupler 1 711, the second optical coupler 2 712, the second optical coupler 3 713, the second optical coupler 4 714, the second optical coupler 5 715, the second optical coupler 6 716, the second optical coupler 717, the second optical coupler 8 718,

[0049] second relay 1 721, second relay 2 722, second relay 3 723, second relay 4 724, second relay 5 725, second relay 6 726, second relay 727, second relay 8 728,

[0050] Second buzzer 73. DETAILED DESCRIPTION

[0051] The technical solution of the present application is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0052] Embodiment one:

[0053] like Figure 1It is a schematic diagram of the structure of an electric pallet truck, including a handle 2, a controller 1, a traction motor 3 and an electromagnetic brake 16, an interlocking switch 14, and a body harness 9. The interlocking switch 14 is installed on the bracket of the handle 2, and the electromagnetic brake 16 is installed on the drive shaft of the traction motor 3. The body harness 9 connects the handle 2, the interlocking switch 14, the traction motor 3, the controller 1, the electromagnetic brake 16, the lifting contactor 12, the lowering solenoid valve 13, the lifting motor 11, etc. into a complete circuit system. During the operation of the vehicle, the rotation frequency and the degree of wear are more serious. There are two torsion harnesses, wherein the first torsion harness 9-1 is the connection line between the handle 2, the interlocking switch 14 installed on the handle bracket and the controller 1 respectively, and the second torsion harness 9-2 is the connection line between the traction motor 3, the electromagnetic brake 16 installed on the drive shaft of the traction motor and the controller 1 respectively.

[0054] like Figure 2 As shown, a testing system for the torsion harness performance of an electric pallet truck includes a first torsion harness 91 connected between the output end of a controller 1 and the handle 2 and the input end of an interlock switch 14, and a second torsion harness 92 connected between the output end of the controller 1 and the input end of a traction motor 3 and an electromagnetic brake 16; the first torsion harness 91 and the second torsion harness 92 are respectively connected to a test harness, and the test harness is connected to a function indicator box; the function indicator box includes a buzzer and a plurality of detection units composed of optical couplers and relays; in each detection unit, the optical coupler is connected to the controller 1, and the relay is connected to the buzzer.

[0055] That is, by observing whether the function indicator box emits a buzzer and whether the light-emitting diode is off, the performance of the vehicle body harness is judged, that is, whether a circuit is broken due to wear and tear, and then whether the selected vehicle body harness is qualified. And when the buzzer sounds an alarm, it is specifically observed in the function indicator box which light-emitting diode of the optocoupler is off, and the specific wire with an open circuit can be judged based on this, and the time when the vehicle body harness 9 fails can also be obtained.

[0056] Among them, the optocoupler and relay are both existing products. The optocoupler includes a phototransistor and a light-emitting diode. The phototransistor is connected to the coil of the relay, and the contact of the relay is connected to the buzzer. The relay is a normally closed relay. When the light-emitting diode is energized and emits light, the coil of the relay is energized to disconnect the contacts, and the buzzer circuit is disconnected; when the light-emitting diode is powered off and extinguished, the coil of the relay loses power to connect the contacts, and the buzzer circuit is connected to alarm.

[0057] The traction motor 3 includes a speed sensor 31 and a temperature sensor 32;

[0058] The second torsion harness 92 is connected to the second function indicator box 7 through the second test harness 5. The second function indicator box 7 includes 8 groups of detection units, among which 5 groups of detection units have one end connected to the controller 1 and the other end connected to the speed sensor 31; 2 groups of detection units have one end connected to the controller 1 and the other end connected to the temperature sensor 32; 1 group of detection units has one end connected to the controller 1 and the other end connected to the controller 1 through the electromagnetic brake 16.

[0059] The handle 2 includes a key switch 21 connected to the battery pack 8, the output end of the key switch 21 is connected to a switch circuit board, and a lifting switch 22, a lowering switch 23, an accelerator 24, a back switch 25, an emergency reverse switch 26, and a horn switch 27 are installed on the switch circuit board;

[0060] The first torsion harness 91 is connected to the first function indicator box 6 through the first test harness 4, and the first function indicator box 6 includes 8 groups of detection units, wherein one end of the first group of detection units is connected to the controller 1, and the other end is connected to the key switch 21; one end of the second group of detection units is connected to the controller 1 through the coil of the lifting contactor 12, and the other end is connected to the lifting switch 22, and the contacts of the lifting contactor 12 are connected in series between the battery pack 8 and the lifting motor 11; one end of the third group of detection units is connected to the controller 1 through the descending solenoid valve 13, and the other end is connected to the descending switch 23; one end of the fourth group of detection units is connected to the controller 1, and the other end is connected to the accelerator 24; one end of the fifth group of detection units is connected to the controller 1, and the other end is connected to the reverse switch 25; one end of the sixth group of detection units is connected to the controller 1, and the other end is connected to the emergency reverse switch 26; one end of the seventh group of detection units is connected to the controller 1 through the interlock switch 14; one end of the eighth group of detection units is connected to the horn switch 27, and the other end is connected to the horn 15.

[0061] In a further solution, the power port of the function indicator box is connected to the vehicle control power supply for power supply;

[0062] The controller 1 and the handle 2 are connected in series at both ends of the battery pack 8, respectively. A second fuse 18 is connected between the positive end of the battery pack 8 and the controller 1; a first fuse 17 and an emergency power-off switch 10 are connected in sequence between the positive end of the battery pack 8 and the handle 2.

[0063] Specific lines such as Figure 3As shown, each wire in the first torsion harness 91 is connected as a starting end to the power output terminal J2-1, the lifting switch signal terminal J2-2, the lowering switch signal terminal J2-3, the acceleration signal terminal J2-4, the reverse switch signal terminal J2-5, the emergency reverse switch signal terminal J2-6, and the horn signal terminal J2-7 in the handle 2; the corresponding terminals are connected to the control power terminal J1-1, the lifting signal terminal J1-4, the lowering signal terminal J1-5, the acceleration signal terminal J1-6, the reverse signal terminal J1-7, the emergency reverse signal terminal J1-8, the interlock signal power terminal J1-3, and the positive power terminal of the horn 15 in the controller 1.

[0064] The second torsion harness 92 is connected as the starting end to the positive and negative power harnesses 9, phase A, phase B, phase C of the speed sensor 31 in the traction motor 3, and the PT+ and PT- signal terminals of the temperature sensor 32; the corresponding ends are connected to the +24V, negative power supply GND1, J1-11, J1-12, J1-13, PT+, PT-, PB+, and PB- ports of the controller 1.

[0065] The first test harness 5 is connected between the first torsion harness 91 and the first function indicator box 6 , and the second test harness 6 is connected between the second torsion harness 92 and the second function indicator box 7 .

[0066] The battery pack 8 provides working power for the test system. The positive output terminal 1B+ of the battery pack 8 is connected to the power output terminal J2-1 in the handle 2 through the first fuse 17 and the emergency power off switch 10. The power output terminal J2-1 provides power for the CMM port connection of the switch circuit board of the handle 2. The power output terminal J2-1 outputs to the control power terminal 3B+ via the light emitting diode of the first optical coupler 611 in the first function indicator box 6. The control power supply terminal 3B+ is connected to the vehicle control battery to supply power to the photosensitive transistors in the eight first optical couplers (the first optical coupler 1 611, the first optical coupler 2 612, the first optical coupler 3 613, the first optical coupler 4 614, the first optical coupler 5 615, the first optical coupler 616, the first optical coupler 7 617, and the first optical coupler 8 618) in the first function indicator box 6, and at the same time, the eight first relays (the first relay 1 621, the first relay 2 622, the first relay 3 623, the first relay 4 624, the first relay 5 625, the first relay 6 626, the first relay 8 618) in the first function indicator box 6. The first relay 727 and the second relay 8 628) are powered; the second relay 724 and the second relay 5 725 are powered by the eight second optical couplers (the second optical coupler 1 711, the second optical coupler 2 712, the second optical coupler 3 713, the second optical coupler 4 714, the second optical coupler 5 715, the second optical coupler 6 716, the second optical coupler 717 and the second optical coupler 8 718) in the second function indicator box 7, and the eight second relays (the second relay 1 721, the second relay 2 722, the second relay 3 723, the second relay 4 724, the second relay 5 725, the second relay 6 726, the second relay 727 and the second relay 8 728) are powered.

[0067] The function ports J2-2, J2-3, J2-4, J2-5, J2-6, and J2-7 of the handle 2 are connected to the positive power supply of ports J1-4, J1-5, J1-6, J1-7, and J1-8 in the controller 1 through the first test harness 4 and the power generating diodes in the first optocoupler (612, 613, 614, 615, 616, and 618) in the first function indicator box 6; the light-emitting diode output end of the first optocoupler 617 is connected to J1-3 in the controller 1 through the interlock switch 14.

[0068] The traction motor 3 is electrically connected to the controller 1. Specifically, the signal terminals +24V, J1-11, J1-12, J1-13, and GND1 in the controller 1 are respectively connected to the signal terminals +24V, phase A, phase B, phase C, and GND3 in the speed sensor 31 through the second optical coupler (715, 712, 713, 714, and 711) in the second function indicator box 7 (the three are one-to-one corresponding, as shown in the figure). Figure 3As shown), the signal ports PT+ and PT- in the temperature sensor 32 are connected to PT+ and PT- in the controller 1 through the second optical coupler (716, 717), respectively; one end of the electromagnetic brake 16 is connected to the second optical coupler 718 through the second test harness 5, and the other end of the electromagnetic brake 16 and the second optical coupler 718 are connected to the signal terminals PB+ and PB- in the controller 1, respectively.

[0069] When the light-emitting diodes in the first photocouplers in the first function indicator box 6 connected to the first twisted wire harness 91 emit light, the corresponding phototransistor generates a photocurrent and outputs a conducting circuit, providing power for the wire packages of each first relay, and the first relay is a normally closed relay, and its contacts are disconnected. Then the buzzer 63 electrically connected to the contacts of the first relay does not work.

[0070] When the light-emitting diodes in the second photocouplers in the second function indicator box 7 connected to the second twisting portion 92 emit light, the corresponding phototransistors generate photocurrents and output conduction circuits to provide power for the coils of the second relays, and the second relays are normally closed relays with their contacts disconnected. The buzzer 73 electrically connected to the contacts of the second relays does not work.

[0071] The positive output terminal 1B+ of the battery pack 8 is connected to the positive power supply 2B+ of the controller 1, and a second fuse 18 is connected in series between the positive output terminal 1B+ of the battery pack 8 and the positive power supply 2B+ of the controller 1. The power output terminal of the second fuse 18 is connected to the positive power supply terminal of the lifting motor 11 via the contacts of the lifting contactor 12.

[0072] Embodiment 2:

[0073] A method for testing the torsion harness performance of an electric pallet truck comprises the following steps:

[0074] S1, connect the first test harness 4 to the first torsion harness 91 connected between the output end of the controller 1 and the handle 2 and the input end of the interlock switch 14, then connect the first test harness 4 to the first function indicator box 6, and the first function indicator box 6 to the controller 1;

[0075] Connect the second test harness 5 to the second torsion harness 92 connected between the output end of the controller 1 and the input end of the traction motor 3 and the electromagnetic brake 16, and then connect the second test harness 5 to the second function indicator box 7, and the second function indicator box 7 to the traction motor 3;

[0076] S2, turn on the power supply, close the key switch 21 in the handle 2, and the switch circuit boards in the controller 1 and the handle 2 are powered on for self-test, and at the same time, power is provided to the optical couplers in the first function indicator box 6 and the second function indicator box 7;

[0077] S3, after closing the key switch 21, operate the lifting switch 22, the lowering switch 23, the interlocking switch 14, the accelerator 24, the reverse switch 25, the emergency reverse switch 26 and the horn switch 27 in sequence, and check whether the light-emitting diodes in the first optical couplers in the first function indicator box 6 are lit; if all of them are lit, it indicates that the performance of the first torsion harness 91 is good; if one of the light-emitting diodes is off, the wire package of the corresponding relay loses power and the contact is connected, and the circuit of the first buzzer 63 is connected and an alarm is sounded, indicating that the first torsion harness 91 is open circuited;

[0078] S4. Check whether the light-emitting diodes in each second optical coupler in the second function indicator box 7 are lit. If all of them are lit, it indicates that the performance of the second torsion harness 92 is good. If one of the light-emitting diodes is off, the corresponding relay coil loses power and the contacts are connected, and the second buzzer 73 circuit is connected and an alarm is sounded, indicating that the second torsion harness 92 is open.

[0079] In a further solution, in step S1, the first function indicator box 6 includes 8 groups of detection units, and the detection units include a first optical coupler and a first relay;

[0080] Among them, one end of the first group of detection units is connected to the controller 1, and the other end is connected to the key switch 21; one end of the second group of detection units is connected to the controller 1 through the coil of the lifting contactor 12, and the other end is connected to the lifting switch 22, and the contacts of the lifting contactor 12 are connected in series between the battery 8 and the lifting motor 11; one end of the third group of detection units is connected to the controller 1) through the descending solenoid valve 13, and the other end is connected to the descending switch 23; one end of the fourth group of detection units is connected to the controller 1, and the other end is connected to the accelerator 24; one end of the fifth group of detection units is connected to the controller 1, and the other end is connected to the reverse switch 25; one end of the sixth group of detection units is connected to the controller 1, and the other end is connected to the emergency reverse switch 26; one end of the seventh group of detection units is connected to the controller 1 through the interlock switch 14; one end of the eighth group of detection units is connected to the horn switch 27, and the other end is connected to the horn 15.

[0081] In step S1, the traction motor 3 includes a speed sensor 31 and a temperature sensor 32;

[0082] The second function indicator box 7 includes 8 groups of detection units, and the detection units include a second optical coupler and a second relay;

[0083] Among them, one end of 5 groups of detection units are connected to the controller 1, and the other end is connected to the speed sensor 31; one end of 2 groups of detection units are connected to the controller 1, and the other end is connected to the temperature sensor 32; one end of 1 group of detection units is connected to the controller 1, and the other end is connected to the controller 1 through the electromagnetic brake 16.

[0084] In a further solution, in step S3, the specific steps are as follows:

[0085] S31, close the key switch 21. When the performance of the first torsion harness 91 is good, the light-emitting diode of the first optical coupler 611 in the first function indicator box 6 is energized and emits light, the coil of the relay is energized and the contact is disconnected, and the circuit of the first buzzer 63 is disconnected; when the light-emitting diode is powered off and extinguished, the coil of the relay loses power and the contact is connected, and the circuit of the first buzzer 63 is connected and an alarm is sounded, indicating that the first torsion harness connected here is open circuit;

[0086] S32, after closing the key switch 21 in the handle 2, when the lifting switch 22 is closed, the first optical coupler 2 612 in the first function indicator box 6 and the wire package of the lifting contactor 12 are energized, so that the contacts of the lifting contactor 12 are connected, and the lifting motor 11 works to drive the fork to rise; if the light-emitting diode in the first optical coupler 2 612 is lit, it indicates that the performance of the first torsion harness 91 is good; when the light-emitting diode in the first optical coupler 2 612 is off, the wire package of the relay loses power and the contacts are connected, and the circuit of the first buzzer 63 is connected and an alarm is sounded; it indicates that the first torsion harness 91 connected here is open circuit;

[0087] S33, after closing the key switch 21 in the handle 2, when the descending switch 23 is closed, the first optical coupler 3 613 and the descending relay 13 in the first function indicator box 6 are energized, the descending relay 13 opens the oil return path of the descending cylinder, and the fork descends; if the light-emitting diode in the first optical coupler 3 613 is lit, it indicates that the performance of the first torsion harness 91 is good; when the light-emitting diode in the first optical coupler 3 613 is off, the relay wire package loses power and the contact is connected, and the first buzzer 63 circuit is connected and an alarm is sounded; it indicates that the first torsion harness 91 connected here is open circuit;

[0088] S34, after closing the key switch 21 in the handle 2, and then closing the interlock switch 14, the light-emitting diode in the first optical coupler 617 in the first function indicator box 6 is energized and emits light; when the light-emitting diode in the first optical coupler 617 is extinguished, the wire package of the relay loses power and the contact is connected, and the circuit of the first buzzer 63 is connected and an alarm is sounded; indicating that the first torsion wire harness 91 connected here is open circuit;

[0089] S35, after closing the key switch 21 and the interlock switch 14, the accelerator 24 in the handle 2 is rotated backwards, the reverse switch 25 is closed, the light-emitting diodes in the first optical coupler 4 614 and the first optical coupler 5 615 are energized and emit light, and the vehicle is controlled to run in the reverse direction at a speed adjustment; if the first optical coupler 4 614 or the first optical coupler 5 615 is off, the wire package of the relay loses power and the contact is connected, and the circuit of the first buzzer 63 is connected and an alarm is sounded; indicating that the first torsion wire harness 91 connected here is open circuit;

[0090] S36, after closing the key switch 21 and the interlock switch 14, the emergency reverse switch 26 is closed, the light emitting diodes in the first optical coupler 616 are all powered on and light up, and the controller 1 controls the traction motor 4 to run in an emergency reverse direction; if the light emitting diodes in the first optical coupler 616 are off, the coil of the relay loses power and the contacts are connected, and the circuit of the first buzzer 63 is connected and an alarm is sounded, indicating that the first torsion harness 91 connected here is open circuited;

[0091] S37, after closing the key switch 21 in the handle 2, then close the horn switch 27, the light-emitting diodes in the first optocoupler 8618 are all energized and illuminated, and the horn 15 works; if the light-emitting diodes in the first optocoupler 8618 are off, the relay coil loses power and the contacts are connected, and the first buzzer 63 circuit is connected and an alarm is sounded, indicating that the first torsion harness 91 connected here is open-circuited.

[0092] The specific process is as follows:

[0093] When the key switch 21 in the handle 2 is turned on, the power output port J2-1 in the handle 2 provides power to the CMM port on the switch circuit board of the handle 2, and the power output port J2-1 is output to the control power port 3B+ of the vehicle via the light-emitting diode of the first optical coupler 611 in the first function indicator box 6. One power supply in the control power port 3B+ of the vehicle is input to the control power port J1-1 in the controller 1, and the controller 1 is powered on for self-test; another power supply is input to the first function indicator box 6 to provide power to the phototransistors in the eight first optical couplers. When the circuit is connected, the light-emitting diode in the first optical coupler 611 emits light, and the phototransistor generates photocurrent and outputs, then the coil of the first relay 621 generates a voltage difference, its contacts are disconnected, and the first buzzer 63 does not work. At the same time, the switch circuit board in the handle 2 is powered on, and the handle 2 completes the self-test. When the lifting switch 22 in the handle 2 is pressed, the 24V high voltage signal is connected in series to the positive terminal of the wire package of the lifting contactor 12 through the lifting switch 22, the first test harness 4 and the light-emitting diode in the second optical coupler 612 in a function indicator box 6, and the negative terminal of the wire package of the lifting contactor 12 is connected to the lifting control port J1-4 of the controller 1. The wire package of the lifting contactor 12 generates a pressure difference. The lifting contactor 12 is normally open, its contacts are connected, and the lifting motor 11 works, thereby driving the oil cylinder to lift the vehicle fork. If the circuit between the handle 2 and the control power supply port J1-1 of the controller 1 is open, the light-emitting diode in the first optical coupler 611 is extinguished, the phototransistor is disconnected, the wire package of the first relay 621 has no pressure difference, its contacts are connected, and the circuit of the first buzzer 63 is connected and works to generate a buzzer alarm.

[0094] Similarly, when other wires of the first and second twisted harnesses 91 and 92 in the vehicle harness 9 are open, the light-emitting diodes in the first and second function indicator boxes 6 and 7 are extinguished, the phototransistors are disconnected, and the first buzzer 63 or the second buzzer 73 circuit is connected to work.

[0095] When the key switch 21 in the handle 2 is turned on and the control power port 3B+ of the vehicle is powered normally, after the controller 1 and the handle 2 complete the self-test, when the descending switch 23 in the handle 2 is pressed, the 24V high voltage signal is connected in series to the descending solenoid valve 13 through the descending switch 23, the light-emitting diode in the first optical coupler 3 613 in the test harness 4 and the first function indicator box 6, and the descending solenoid valve 13 is energized to open the oil circuit, so that the fork is lowered. When the relevant connecting line is open, the light-emitting diode in the first optical coupler 3 613 is extinguished, the phototransistor is disconnected, the line package of the first relay 3 623 has no pressure difference, the contact is connected, and the first buzzer 63 works.

[0096] When the key switch 21 in the handle 2 is turned on, the vehicle's control power port 3B+ provides 24V power normally. When the handle is pressed down to the area where the vehicle is allowed to run, the interlock switch 14 is closed, and the 24V power is connected in series to the interlock signal port J1-3 of the controller 1 through the light-emitting diode in the first optical coupler 7617 in the test harness 4 and the first function indicator box 6, and the controller 1 allows the vehicle to run. When the relevant connection line is open, the light-emitting diode in the first optical coupler 7617 is extinguished, the phototransistor is disconnected, the line package of the first relay 7627 has no pressure difference, the contact is connected, and the first buzzer 63 works.

[0097] When the key switch 21 in the handle 2 is turned on, the control power port 3B+ of the vehicle is powered normally, after the controller 1 and the handle 2 complete the self-test, and the interlock switch 14 is turned on, when the accelerator 24 in the handle 2 is rotated forward, the speed control signal is connected in series to the speed control port J1-6 of the controller 1 through the light-emitting diode in the first optical coupler 4 614 in the test harness 4 and the first function indicator box 6, and the controller 1 controls the traction motor 3 to adjust the speed according to the forward acceleration command signal, and the vehicle adjusts the speed in the forward direction. When the relevant connecting line is open, the light-emitting diode in the first optical coupler 4 614 is extinguished, the photosensitive transistor is disconnected, the coil of the first relay 4 624 has no pressure difference, the contact is connected, and the first buzzer 63 works.

[0098] When the key switch 21 in the handle 2 is turned on, the control power port 3B+ of the vehicle is powered normally, after the controller 1 and the handle 2 complete the self-test, the interlock switch 14 is turned on, when the accelerator 24 in the handle 2 is rotated backward, and the reverse switch 25 is turned on, the reverse signal is connected in series to the reverse control port J1-7 of the controller 1 through the light emitting diode in the first optical coupler 5 615 in the test harness 4 and the first function indicator box 6, and the speed control signal is connected in series to the speed control port J1-6 of the controller 1 through the light emitting diode in the first optical coupler 5 615 in the test harness 4 and the first function indicator box 6. The controller 1 controls the traction motor 3 to adjust the speed according to the reverse instruction and the acceleration command signal, and the vehicle adjusts the speed in the reverse direction. When the relevant connecting line is open, the light emitting diode of the first optical coupler 4 614 or the first optical coupler 5 615 is extinguished, and the corresponding photosensitive transistor is disconnected, then the wire package of the connected first relay 4 624 or the first relay 5 625 has no pressure difference, the contact is connected, and the first buzzer 63 works.

[0099] When the key switch 21 in the handle 2 is turned on and the control power port 3B+ of the vehicle is powered normally, after the controller 1 and the handle 2 complete the self-test and the interlock switch 14 is turned on, the emergency reverse switch 26 in the handle 2 is triggered to turn on the emergency reverse switch 26. The emergency reverse signal is connected in series to the emergency reverse signal port J1-8 of the controller 1 through the light-emitting diode in the first optical coupler 6616 in the test harness 4 and the first function indicator box 6. The controller 1 controls the traction motor 3 to run in reverse according to the emergency reverse signal. When the relevant connecting line is open, the light-emitting diode in the first optical coupler 6616 is extinguished, the phototransistor is disconnected, the coil of the first relay 6626 has no pressure difference, the contact is connected, and the first buzzer 63 works.

[0100] When the key switch 21 in the handle 2 is turned on and the control power port 3B+ of the vehicle is powered normally, after the handle 2 completes the self-test, the horn switch 27 in the handle 2 is pressed, and the horn signal passes through the light-emitting diode in the first optical coupler 8618 in the test harness 4 and the first function indicator box 6 to connect the positive power supply of the horn switch 27, and the horn sounds. When the relevant connecting line is open, the light-emitting diode in the first optical coupler 8618 is extinguished, the phototransistor is disconnected, the line package of the first relay 8628 has no pressure difference, the contact is connected, and the first buzzer 63 works.

[0101] The second torsion harness 92 in the vehicle body harness 9 is a connection line between the traction motor 3 and the electromagnetic brake 16 on the traction motor drive shaft and the controller 1. When the positive power supply +24V, negative power supply GND3, phase A, phase B, phase C of the speed sensor 3-1 on the traction motor 3, PT+, PT- in the temperature sensor 3-2, and the lead-out wires of the electromagnetic brake 16 package are reliably connected to the +24V, GND1, J1-11, J1-12, J1-13, PT+, PT-, PB+, PB- ports in the controller 1 respectively, the light-emitting diodes in each second optical coupler (711, 712, 713, 714, 715, 716, 717, 718) in the second function indicator box 7 connected in series are turned on, and the vehicle can work normally. When the above-mentioned related connecting lines are open, the light-emitting diodes in each second optocoupler are extinguished, the corresponding photosensitive transistors are disconnected, the wire packages of the second relays (721, 722, 723, 724, 725, 726, 727, 728) connected thereto have no pressure difference, the contacts are connected, and the second buzzer 73 works to emit a buzzer alarm.

[0102] When the tester hears the first buzzer 63 or the second buzzer 73 beeping alarm, he observes whether the light emitting diodes in the first and second function indicator boxes 6 and 7 are extinguished, thereby determining which wires are open-circuited and obtaining the exact time when the vehicle body wiring harness 9 fails.

[0103] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application are within the scope of protection of the pending claims of the present application.

Claims

1. A testing system for torsion harness performance of an electric pallet truck, comprising a first torsion harness (91) connected between an output end of a controller (1) and an input end of a handle (2) and an interlock switch (14), and a second torsion harness (92) connected between an output end of the controller (1) and an input end of a traction motor (3) and an electromagnetic brake (16); characterized in that: The first torsion harness (91) and the second torsion harness (92) are respectively connected to a test harness, and the test harness is connected to a function indicator box; the function indicator box comprises a buzzer and a plurality of detection units consisting of optical couplers and relays; in each detection unit, the optical coupler is connected to the controller (1), and the relay is connected to the buzzer.

2. The test system according to claim 1, characterized in that: The optocoupler includes a phototransistor and a light-emitting diode. The phototransistor is connected to the coil of the relay, and the contact of the relay is connected to the buzzer. The relay is a normally closed relay. When the light-emitting diode is powered on and emits light, the coil of the relay is energized and the contact is disconnected, and the buzzer circuit is disconnected; when the light-emitting diode is powered off and extinguished, the coil of the relay loses power and the contact is connected, and the buzzer circuit is connected to alarm.

3. The test system according to claim 1, characterized in that: The traction motor (3) comprises a speed sensor (31) and a temperature sensor (32); The second torsion harness (92) is connected to the second function indicator box (7) via the second test harness (5); the second function indicator box (7) comprises 8 groups of detection units, wherein 5 groups of detection units have one end connected to the controller (1) and the other end connected to the speed sensor (31); 2 groups of detection units have one end connected to the controller (1) and the other end connected to the temperature sensor (32); and 1 group of detection units has one end connected to the controller (1) and the other end connected to the controller (1) via the electromagnetic brake (16).

4. The test system according to claim 1, characterized in that: The handle (2) comprises a key switch (21) connected to the battery pack (8); an output end of the key switch (21) is connected to a switch circuit board; a lifting switch (22), a lowering switch (23), an accelerator (24), a reverse switch (25), an emergency reverse switch (26), and a horn switch (27) are mounted on the switch circuit board; The first torsion harness (91) is connected to the first function indicator box (6) through the first test harness (4), and the first function indicator box (6) includes 8 groups of detection units, wherein one end of the first group of detection units is connected to the controller (1) and the other end is connected to the key switch (21); one end of the second group of detection units is connected to the controller (1) through the coil of the lifting contactor (12) and the other end is connected to the lifting switch (22), and the contact of the lifting contactor (12) is connected in series between the battery pack (8) and the lifting motor (11); one end of the third group of detection units is connected to the lowering solenoid valve (12) through the lowering solenoid valve (11) 3) is connected to the controller (1), and the other end is connected to the descending switch (23); one end of the fourth group of detection units is connected to the controller (1), and the other end is connected to the accelerator (24); one end of the fifth group of detection units is connected to the controller (1), and the other end is connected to the reverse switch (25); one end of the sixth group of detection units is connected to the controller (1), and the other end is connected to the emergency reverse switch (26); one end of the seventh group of detection units is connected to the controller (1) through the interlocking switch (14); one end of the eighth group of detection units is connected to the horn switch (27), and the other end is connected to the horn (15).

5. The test system according to claim 1, characterized in that: The power port of the function indicator box is connected to the vehicle control power supply for power supply; The controller (1) and the handle (2) are respectively connected in series at two ends of a battery pack (8); a second fuse (18) is connected between the positive end of the battery pack (8) and the controller (1); and a first fuse (17) and an emergency power-off switch (10) are sequentially connected between the positive end of the battery pack (8) and the handle (2).

6. A method for testing the torsion harness performance of an electric pallet truck, characterized in that: The steps include: S1, connecting a first test harness (4) to a first torsion harness (91) connected between an output end of the controller (1) and a handle (2) and an input end of an interlock switch (14), and then connecting the first test harness (4) to a first function indicator box (6), and the first function indicator box (6) to the controller (1); A second test harness (5) is connected to a second torsion harness (92) connected between an output end of the controller (1) and an input end of the traction motor (3) and an electromagnetic brake (16), and the second test harness (5) is then connected to a second function indicator box (7), and the second function indicator box (7) is connected to the traction motor (3); S2, turning on the power supply, closing the key switch (21) in the handle (2), and the controller (1) and the switch circuit board in the handle (2) are powered on for self-test, and at the same time, power is provided to the optical couplers in the first function indicator box (6) and the second function indicator box (7); S3, after closing the key switch (21), operate the lifting switch (22), the lowering switch (23), the interlocking switch (14), the accelerator (24), the reverse switch (25), the emergency reverse switch (26) and the horn switch (27) in sequence to check whether the light-emitting diodes in the first optical couplers in the first function indicator box (6) are illuminated; if all of them are illuminated, it indicates that the performance of the first torsion harness (91) is good; if one of the light-emitting diodes is off, the wire package of the corresponding relay loses power and the contact is connected, and the circuit of the first buzzer (63) is connected to alarm, indicating that the first torsion harness (91) is open circuit; S4. Check whether the light-emitting diodes in the second optical couplers in the second function indicator box (7) are illuminated. If all of them are illuminated, it indicates that the performance of the second torsion harness (92) is good. If one of the light-emitting diodes is off, the corresponding relay coil loses power and the contacts are connected, and the second buzzer 73 circuit is connected and an alarm is sounded, indicating that the second torsion harness (92) is open-circuited.

7. The testing method according to claim 6, characterized in that: In step S1, the first function indicator box (6) includes 8 sets of detection units, and the detection units include a first optical coupler and a first relay; One end of the first detection unit is connected to the controller (1) and the other end is connected to the key switch (21); one end of the second detection unit is connected to the controller (1) through the coil of the lifting contactor (12) and the other end is connected to the lifting switch (22), and the contact of the lifting contactor (12) is connected in series between the battery pack (8) and the lifting motor (11); one end of the third detection unit is connected to the controller (1) through the descending solenoid valve (13) and the other end is connected to the descending switch (23); one end of the fourth detection unit is connected to the controller (1) and the other end is connected to the accelerator (24); one end of the fifth detection unit is connected to the controller (1) and the other end is connected to the reverse switch (25); one end of the sixth detection unit is connected to the controller (1) and the other end is connected to the emergency reverse switch (26); one end of the seventh detection unit is connected to the controller (1) through the interlocking switch (14); one end of the eighth detection unit is connected to the horn switch (27) and the other end is connected to the horn (15).

8. The testing method according to claim 6, characterized in that: In step S1, the traction motor (3) includes a speed sensor (31) and a temperature sensor (32); The second function indicator box (7) comprises 8 groups of detection units, each of which comprises a second optical coupler and a second relay; One end of each of the five detection units is connected to the controller (1), and the other end is connected to the speed sensor (31); one end of each of the two detection units is connected to the controller (1), and the other end is connected to the temperature sensor (32); one end of each of the detection units is connected to the controller (1), and the other end is connected to the controller (1) via an electromagnetic brake (16).

9. The testing method according to claim 6, characterized in that: In step S3, the specific steps are as follows: S31, closing the key switch (21), when the performance of the first torsion harness (91) is good, the light-emitting diode of the first optical coupler (611) in the first function indicator box (6) is energized and emits light, the coil of the relay is energized and the contacts are disconnected, and the circuit of the first buzzer (63) is disconnected; when the light-emitting diode is de-energized and extinguished, the coil of the relay loses power and the contacts are connected, and the circuit of the first buzzer (63) is connected and an alarm is sounded, indicating that the first torsion harness connected here is open circuit; S32, after closing the key switch (21), when the lifting switch (22) is closed, the first optical coupler 2 (612) in the first function indicator box (6) and the coil of the lifting contactor (12) are energized, so that the contacts of the lifting contactor (12) are connected, and the lifting motor (11) works to drive the fork to rise; if the light-emitting diode in the first optical coupler 2 (612) lights up, it indicates that the performance of the first torsion harness (91) is good; when the light-emitting diode in the first optical coupler 2 (612) is off, the coil of the relay loses power and the contacts are connected, and the circuit of the first buzzer (63) is connected to alarm, indicating that the first torsion harness (91) connected here is open circuit; S33, after closing the key switch (21) in the handle (2), when the descending switch (23) is closed, the first optical coupler (613) and the descending relay (13) in the first function indicator box (6) are energized, the descending relay (13) opens the oil return path of the descending oil cylinder, and the fork descends; if the light-emitting diode in the first optical coupler (613) is lit, it indicates that the performance of the first torsion harness (91) is good; when the light-emitting diode in the first optical coupler (613) is off, the relay coil loses power and the contact is connected, and the first buzzer (63) circuit is connected to alarm; indicating that the first torsion harness (91) connected here is open circuit; S34, after closing the key switch (21) in the handle (2), the interlock switch (14) is closed, and the light-emitting diode in the first optical coupler (617) in the first function indicator box (6) is energized and emits light; when the light-emitting diode in the first optical coupler (617) is extinguished, the wire package of the relay loses power and the contact is connected, and the circuit of the first buzzer (63) is connected and an alarm is sounded, indicating that the first torsion wire harness (91) connected here is open circuited; S35, after closing the key switch (21) and the interlock switch (14), the accelerator (24) in the handle (2) is rotated backwards, the reverse switch (25) is closed, and the light-emitting diodes in the first optical coupler four (614) and the first optical coupler five (615) are energized and emit light, and the vehicle is controlled to run in the reverse direction at a variable speed; if the first optical coupler four (614) or the first optical coupler five (615) is extinguished, the relay coil loses power and the contact is connected, and the first buzzer (63) circuit is connected and an alarm is sounded, indicating that the first torsion harness (91) connected here is open circuited; S36, after closing the key switch (21) and the interlock switch (14), the emergency reverse switch (26) is closed, the light emitting diodes in the first optical coupler (616) are all powered on and emit light, and the controller (1) controls the traction motor (4) to run in an emergency reverse manner; if the light emitting diodes in the first optical coupler (616) are extinguished, the coil of the relay loses power and the contacts are connected, and the circuit of the first buzzer (63) is connected to alarm, indicating that the first torsion harness (91) connected here is open circuited; S37, after closing the key switch (21) in the handle (2), the horn switch (27) is then closed, and the light-emitting diodes in the first optocoupler eight (618) are all energized and illuminated, and the horn (15) works; if the light-emitting diodes in the first optocoupler eight (618) are extinguished, the relay coil loses power and the contacts are connected, and the first buzzer (63) circuit is connected and an alarm is sounded, indicating that the first torsion harness (91) connected here is open-circuited.

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