WO2024108983A1

WO2024108983A1 - Forklift starting anti-rollback control method, forklift automatic parking control method and forklift control system

Info

Publication number: WO2024108983A1
Application number: PCT/CN2023/100193
Authority: WO
Inventors: 张冬林; 毕胜; 白迎春; 师学银; 郑小东; 夏光
Original assignee: 安徽合力股份有限公司
Priority date: 2022-11-23
Filing date: 2023-06-14
Publication date: 2024-05-30
Also published as: CN115892010A

Abstract

Disclosed in the present invention is a forklift starting anti-rollback control method, comprising the following steps: S1, collecting state information of a forklift so as to acquire the mass of the forklift; S2, calculating a critical driving force required for the forklift to start without rolling back on the basis of the collected state information of the forklift and the mass of the forklift; S3, calculating the target rotation speed of an engine on the basis of the critical driving force and a universal characteristic curve of the forklift engine; S4, when the forklift is in a forward gear state, stepping on an accelerator pedal of the forklift, enabling the engine to start up and reach the target rotation speed, and controlling the clutch duty ratio and releasing forklift braking so as to allow the forklift to be in a balanced state; and S5, continuously stepping on the accelerator pedal, throttling up, and allowing the forklift to slowly start on a ramp. The forklift starting anti-rollback control method may assist in ramp starting of forklifts, thereby reducing the fatigue degree of drivers during driving, and improving the driving safety; and may also autonomously judge and actively brake when an emergency occurs, thereby further avoiding safety accidents.

Description

A forklift start-up anti-slip and automatic parking control method and control system

Technical Field

The invention relates to the field of vehicle slope parking and starting assistance, in particular to a forklift starting anti-slip and automatic parking control method and control system.

Background technique

With the popularity of forklifts, many forklift drivers often use forklifts in various working conditions, including parking on a slope. Since the forklift's own weight and load capacity are not light, the forklift often slides on the slope due to the driver's lack of concentration and slow braking measures, causing safety accidents. And when the forklift starts on a half-slope, since there is no slope assistance, the driver often needs to rely on his own experience to control the accelerator and brake pedals to ensure that the forklift does not slide. However, the working quality of the forklift is quite large, and often experienced drivers cannot ensure that the forklift does not slide when starting. Therefore, safety accidents are prone to occur and tires slip, reducing the service life of tires.

Summary of the invention

The object of the present invention is to provide a forklift start-up anti-slope and automatic parking control method and control system to solve the problems raised in the above-mentioned background technology.

To achieve the above object, the present invention provides the following technical solutions:

A forklift start-up anti-slip control method comprises the following steps:

S1, collect forklift status information and obtain forklift quality;

S2, calculating the critical driving force for the forklift to start without sliding down the slope by collecting the forklift status information and the forklift mass;

S3, calculating the target speed of the engine through the critical driving force and the universal characteristic curve of the forklift engine;

S4: When the forklift is in the forward gear, press the accelerator pedal, the engine starts and reaches the target speed, the clutch duty cycle is controlled and the forklift brake is released at the same time, so that the forklift is in a balanced state;

S5. Continue to depress the accelerator pedal, increase the throttle, and the forklift starts slowly on the slope.

In a further solution, the forklift status information includes accelerator pedal status information, brake pedal status information, vehicle speed status, and ramp information of the forklift's current location.

As a further solution of the present invention: the forklift status information includes accelerator pedal status information, brake pedal status information, vehicle speed status, and ramp information of the forklift's current location.

As a further solution of the present invention: the forklift mass is obtained through the forklift's ramp-mass-deceleration diagram and the forklift's current position ramp information and forklift deceleration information.

As a further solution of the present invention: the forklift deceleration is obtained by a forklift speed sensor, firstly, the speed v1 of the forklift at the previous moment is obtained by using the forklift, and then the speed v2 at the current moment is obtained, and the time difference is the acquisition frequency time The interval Δt; the braking deceleration

As a further solution of the present invention: the ramp-mass-deceleration diagram of the forklift is obtained by the following steps;

Step 1. Set the empty mass of the forklift to m ₀ , the load range to m ₁ ~m _y , and evenly divide the load range into y-1 segments with a total of y points, namely m ₁ ,m ₂ ,m ₃ ...m _y-2 ,m _y-1 , _my . Therefore, the working mass of the forklift is m ₀ ,m ₁ +m ₀ ,m ₂ +m ₀ ,m ₃ +m ₀ ...m _y-2 +m ₀ ,m _y-1 +m ₀ ,m _y +m ₀ ; the slope value is b%, the unit change difference of the slope value is adjusted to c%, and the upper limit of the slope value is (b+cx)%; the slope-mass-deceleration diagram determines that the number of experimental tests is (y+1)×(x+1);

Step 2: Drive the unloaded forklift up a slope with a gradient value of b% at a reasonable speed v. After going up the slope, the driver immediately releases the accelerator pedal and does not perform any operation on the accelerator pedal and the brake pedal. The speed sensor collects and records the current braking deceleration _a10 ; add cargo with a mass of _m1 , and the mass of the forklift is ( _m0 + _m1 ); repeat step b, collect and record the current braking deceleration _a10 , and repeat step 4b until the braking decelerations corresponding to different loads at all slope values of b% are collected;

Step 3. Keeping the other conditions unchanged, adjust the slope values to b%, (b+2)%, ..., (b+2x-2)%, (b+2x)% respectively and repeat step 4b to obtain the braking deceleration values corresponding to the working mass of the forklift being m ₀ , m ₁ +m ₀ , m ₂ +m ₀ , m ₃ +m ₀ ...m _y-2 +m ₀ ,m _y-1 +m ₀ ,m _y +m ₀ as (a ₀₀ ,a ₀₁ ...a _0y-1 ,a _0y ),(a ₁₀ ,a ₁₁ ...a _1y-1 ,a _1y )...(a _x0 ,a _x1 ...a _xy-1 ,a _xy );

Step 4. After obtaining the braking deceleration values corresponding to (y+1)×(x+1) different slopes and different working masses, use (m ₀ ,b,a ₀₀ );(m ₁ ,b+2,a ₁₁ )...(m _y-1 ,b+2x-2,a _(x-1)(y-1) );(m _y ,b+2x,a _xy ), these (y+1)×(x+1) sets of data to determine xy planes, and connect the xy planes to obtain the slope-mass-deceleration diagram.

As a further solution of the present invention: the critical driving force is F _t =Gsinθ+F _f cosθ=mg(sinθ+μcosθ);

Where _Ft is the critical driving force, _Ff is the friction force, G is the weight of the forklift, and θ is the slope angle where the forklift is located;

Where _Ft is the critical driving force, _Ff is the friction force, G is the weight of the forklift, and θ is the slope angle where the forklift is located.

As a further solution of the present invention: the target speed of the engine is obtained by querying the engine universal characteristic curve and the target output torque, and the target output torque is

Wherein, _Ft is the aforementioned critical driving force, _Ttq is the target output torque of the engine; _ig is the transmission speed ratio; _i0 is the main reducer speed ratio; _ηt is the mechanical efficiency of the entire transmission system; and r is the wheel rolling radius.

The second invention object of the present invention is to provide a forklift ramp automatic parking control method, comprising the following steps: obtaining forklift speed information, accelerator pedal information, and ramp information of the forklift's current location,

The obtained forklift status information is processed to determine whether the forklift meets the automatic parking condition. If the automatic parking condition on the slope is met, the parking brake solenoid valve is turned on for braking, and the forklift automatically parks on the slope.

As a further solution of the present invention: when the forklift speed is less than 3 km/h, the accelerator pedal is in a zero state, and the slope of the forklift's current position is 3°, and the three judgment conditions are met at the same time, it is judged that the forklift enters the automatic parking condition on the slope.

The third invention object of the present invention is to provide a forklift control system, comprising:

A vehicle speed sensor is installed at the wheel of the forklift to collect vehicle speed information;

A brake pedal signal sensor, which is installed on the brake pedal and is used to collect the driver's operation signal on the brake pedal;

An accelerator pedal switch signal sensor is installed on the accelerator pedal and is used to collect the driver's operation signal on the accelerator pedal;

An engine speed sensor, which is mounted on the engine output shaft and is used to collect engine speed signals;

A vehicle gear position signal sensor, which is installed on the gear position operating handle and is used to collect signals of whether the vehicle is currently in forward gear, reverse gear or neutral gear;

A slope sensor, which is mounted on the vehicle body and is used to collect a slope signal of the forklift;

A parking brake solenoid valve, wherein the parking brake solenoid valve is a switch valve;

A processor, wherein the input end of the processor is respectively connected to the vehicle speed sensor, the brake pedal signal sensor, the accelerator pedal switch signal sensor, the engine speed sensor, the vehicle gear signal, and the slope sensor, and the output end of the processor is connected to the parking brake solenoid valve.

Compared with the prior art, the present invention has the following beneficial effects:

1. The automatic parking on a slope and the anti-slip control method for a forklift when starting on different slopes proposed in the present invention can improve the driver's driving experience, greatly reduce the driver's fatigue level during driving, improve driving safety, and can independently judge and actively brake when an emergency occurs, further avoiding the occurrence of safety accidents.

2. The forklift slope start anti-slip auxiliary function proposed by the present invention can effectively prevent the forklift from sliding backwards due to improper cooperation of the driver when the forklift starts on a slope.

3. The forklift hill start anti-slip auxiliary function proposed by the present invention can effectively avoid the phenomenon of wheel slippage caused by the actual driving force greatly exceeding the required critical driving force due to the driver's improper operation of the accelerator pedal during the hill start process, and can effectively increase the actual service life of the wheel.

4. The present invention can quickly, conveniently and economically realize the active safety braking function of the forklift on the slope by collecting signals from slope sensors, vehicle speed sensors, accelerator pedal switch signal sensors and brake pedal signal sensors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a slope-mass-deceleration diagram of the present embodiment;

FIG. 2 is a schematic diagram of force analysis of adjacent driving forces in this embodiment.

Detailed ways

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.

Please refer to Figures 1-2. In an embodiment of the present invention, a forklift control system is applied to a forklift and includes a vehicle speed sensor, a brake pedal signal sensor, an accelerator pedal switch signal sensor, an engine speed sensor, a vehicle gear signal sensor, a slope sensor, a parking brake solenoid valve and a processor.

The vehicle speed sensor is installed at the wheel of the forklift to collect vehicle speed information; the brake pedal signal sensor is installed on the brake pedal to collect the driver's operation signal of the brake pedal; the accelerator pedal switch signal sensor is installed on the accelerator pedal to collect the driver's operation signal of the accelerator pedal; the engine speed sensor is installed on the engine output shaft to collect the engine speed signal; the vehicle gear signal sensor is installed on the gear operating handle to collect the signal that the vehicle is currently in forward gear, reverse gear or neutral gear; the slope sensor is installed on the vehicle body to collect the slope signal of the forklift; the parking brake solenoid valve is a switch valve; the input end of the processor is respectively connected to the vehicle speed sensor, brake pedal signal sensor, accelerator pedal switch signal sensor, engine speed sensor, vehicle gear signal, slope sensor, and the output end of the processor is connected to the parking brake solenoid valve.

A control method for automatic parking of a forklift on a ramp, the control method is performed according to the following steps:

The vehicle speed sensor, accelerator pedal switch signal sensor, and slope sensor collect vehicle speed signals, driver's accelerator pedal operation signals, and slope angle signals, respectively. The collected signals are input into the processor to determine whether the automatic slope parking condition has been entered. If the vehicle speed information detection signal is less than 3km/h, the accelerator pedal switch signal sensor detection signal is zero, and the slope angle signal detection is greater than 2 degrees. If the above three signal conditions are met at the same time, it is determined that the automatic slope parking condition has been entered. If the automatic slope parking condition is met, the processor controls the parking brake solenoid valve to open for braking, and the forklift automatically parks on the slope;

A control method for preventing a vehicle from sliding down a slope when starting with different slopes is provided, wherein the control method is performed in the following steps:

S1. Before automatic parking on a slope, the accelerator pedal switch signal sensor and the brake pedal signal sensor respectively collect the driver's operation signals on the accelerator pedal and the brake pedal. If the driver does not output any operation signal to the accelerator pedal and the brake pedal, the vehicle speed sensor collects the braking deceleration. The braking deceleration collection method uses the speed sensor to collect the speed v1 at the previous moment and the speed v2 at the current moment. The time difference is the collection frequency time interval Δt. The braking deceleration is

The slope sensor collects slope information and determines the current mass of the forklift through the slope-mass-deceleration diagram. The slope-mass-deceleration empirical value diagram is obtained by the following method:

Step 1. Set the empty mass of the forklift to m ₀ , the normal load range to m ₁ ~m _y , and evenly divide the load range into y-1 sections with a total of y points, namely m ₁ , m ₂ , m ₃ ...m _y-2 ,m _y-1 ,m _y , so the working mass of the forklift is m ₀ ,m ₁ +m ₀ ,m ₂ +m ₀ ,m ₃ +m ₀ ...m _y-2 +m ₀ ,m _y-1 +m ₀ ,m _y +m ₀ ; the slope value is b%, and the unit change difference of the slope value in this embodiment is c%, and the change value can be adjusted according to different actual conditions. In this embodiment, the value of c is 2, and the upper limit of the slope value is (b+2x)%. The upper limit of the slope is also determined according to the actual set maximum working slope; the slope-mass-deceleration empirical value diagram determines that the number of experimental tests is (y+1)×(x+1);

Step 2: Drive the unloaded forklift at a reasonable speed v up a slope with a gradient value of b%. After going up the slope, the driver immediately releases the accelerator pedal and does not perform any operation on the accelerator pedal and the brake pedal. The speed sensor collects and records the current braking deceleration a ₁₀ ; add cargo with a mass of m ₁ , and the mass of the forklift is (m ₀ +m ₁ ). Repeat step b, collect and record the current braking deceleration a ₁₀ , and repeat step b until the braking decelerations corresponding to different loads at all slope values of b% are collected;

Step 3. Keeping the other conditions unchanged, adjust the slope values to b%, (b+2)%, ..., (b+2x-2)%, (b+2x)% respectively and repeat step 1b to obtain the braking deceleration values corresponding to the working mass of the forklift being m ₀ ,m ₁ +m ₀ ,m ₂ +m ₀ ,m ₃ +m ₀ ...m _y-2 +m ₀ ,m _y-1 +m ₀ ,m _y +m ₀ as (a ₀₀ ,a ₀₁ ...a _0y-1 ,a _0y ),(a ₁₀ ,a ₁₁ ...a _1y-1 ,a _1y )...(a _x0 ,a _x1 ...a _xy-1 ,a _xy );

Step 4, after obtaining the braking deceleration values corresponding to different working masses of different slopes (y+1)×(x+1), use (m ₀ ,b,a ₀₀ );(m ₁ ,b+2,a ₁₁ )...(m _y-1 ,b+2x-2,a _(x-1)(y-1) );(m _y ,b+2x,a _xy ), these (y+1)×(x+1) groups of data to determine xy planes, and connect the xy planes to obtain the slope-mass-deceleration diagram;

S2. Perform force analysis on the forklift ramp parking condition, comprehensively consider the actual working conditions such as different weather and road conditions, calculate the road adhesion coefficient and friction coefficient as 0.63, and determine the critical driving force for starting without slipping. The critical driving force can be calculated according to the ramp parking force analysis diagram. After force analysis, the critical driving force F _t =G sin θ+F _f cos θ=mg(sin θ+μ cos θ) that can drive the forklift to start in the equilibrium state is calculated;

S3. Determine the target engine speed through the driving force formula, critical driving force, and engine universal characteristic curve. The engine speed n corresponding to the target output torque of the engine can be determined through the engine universal characteristic curve. This speed n is determined as the target speed. The driving force formula is F _t = T _tq × i _g × i ₀ × η _t × r. Therefore, the target engine speed is The output torque is

Where _Ft is the critical driving force, _Ttq is the target output torque of the engine; _ig is the transmission speed ratio; _i0 is the main reducer speed ratio; _ηt is the mechanical efficiency of the entire transmission system; and r is the wheel rolling radius.

S4. The driver engages the forward gear and slowly steps on the accelerator pedal. The engine speed sensor collects the engine speed reaching the set target speed and the gear signal sensor detects that it is currently in the forward gear. The forward gear clutch duty cycle is controlled to be 90%, and the processor controls the automatic release of the parking brake oil pressure valve. At this time, the whole vehicle is in a balanced state.

S5. The driver continues to press the accelerator pedal, the forklift starts slowly on the slope, and the clutch duty cycle is adjusted to 100% compaction, and the forklift starts smoothly.

Example 1

The automatic parking control system and control method for a forklift on a ramp and for preventing the vehicle from sliding downhill when starting on different slopes of the present invention are applied to a 3-ton counterbalanced forklift, which has a vehicle mass of m ₀ =3639 kg; a transmission ratio i _g =2.8; a main reducer ratio i ₀ =6.3; a mechanical efficiency of the entire transmission system η _t =95%; and a wheel rolling radius r =0.36.

The control process of automatic parking on a forklift ramp is as follows:

The vehicle speed signal, the driver's accelerator pedal operation signal, and the slope angle signal are collected; by identifying the collected signals, the vehicle speed signal v=2.5km/h (<3km/h), the accelerator pedal switch signal sensor detection signal is zero, and the slope angle signal θ=3°; the processor determines that the automatic parking condition has been entered according to the above collected signals, and turns on the parking brake solenoid valve for braking, so that the forklift can achieve automatic slope parking.

Example 2

The control method for preventing forklifts from sliding downhill when starting at different slopes is as follows:

S1. Collect the braking deceleration value before automatic parking on the slope, the speed value v ₁ collected at the first moment t ₁ =10 km/h, and the speed value v ₂ collected at the second moment t ₂ =5 km/h. Δt=t ₁ -t ₂ =0.163 s.

Braking deceleration The current slope value information is collected through the slope angle signal as 5.5°, that is, a 10% slope.

The current total mass of the forklift is determined to be m=5000kg through the slope-mass-deceleration empirical value diagram.

S2. Through the force analysis of the forklift ramp parking condition force diagram, the critical driving force that can drive the forklift to start in the equilibrium state is F _t = mg (sin θ + μ cos θ) = 3730N

The driving force formula determines the engine target output torque

S3. Determine the target speed as 1400 r/min through the engine universal characteristic curve.

S4: The driver puts the car in forward gear and slowly steps on the accelerator pedal. The engine speed sensor collects the engine speed reaching the set target speed of 1400 r/min and the gear signal sensor detects that the car is currently in forward gear. The processor The forward clutch duty ratio is controlled to 90%, and the parking brake oil pressure valve is automatically released. At this time, the vehicle is in a balanced state and will not slide down the slope.

S5. The driver continues to press the accelerator pedal, and the forklift starts slowly on the slope. The clutch duty cycle is adjusted to 100% compaction, and the forklift starts smoothly.

In summary, the forklift automatic parking on slope and anti-slip control system and control method for starting with different slopes of the present invention can effectively realize the forklift automatic parking on slope and anti-slip control for starting with different slopes, thereby improving the safety of the counterbalanced forklift's parking and starting on slope and the driver's driving experience.

It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Those skilled in the art should take the specification as a whole, and the technical solutions in the various embodiments can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

A forklift start-up anti-slip control method, characterized in that it comprises the following steps:

S1, collect forklift status information and obtain forklift quality;

S2, calculating the critical driving force for the forklift to start without sliding down the slope by collecting the forklift status information and the forklift mass;

S3, calculating the target speed of the engine through the critical driving force and the universal characteristic curve of the forklift engine;

S4: When the forklift is in the forward gear, press the accelerator pedal, the engine starts and reaches the target speed, the clutch duty cycle is controlled and the forklift brake is released at the same time, so that the forklift is in a balanced state;

S5. Continue to depress the accelerator pedal, increase the throttle, and the forklift starts slowly on the slope.
The forklift start-up anti-slope control method according to claim 1 is characterized in that the forklift status information includes accelerator pedal status information, brake pedal status information, vehicle speed status, and slope information of the forklift's current location.
According to the forklift starting anti-slope control method of claim 1, it is characterized in that the forklift mass is obtained through the forklift's slope-mass-deceleration speed icon and the forklift's current position slope information and forklift deceleration information.
According to claim 3, a forklift start-up anti-slope control method is characterized in that the forklift deceleration is obtained by a forklift speed sensor, firstly using the forklift to obtain the speed v1 of the forklift at the previous moment, and then obtaining the speed v2 at the current moment, and the time difference is the acquisition frequency time interval Δt; the braking deceleration
The forklift start anti-slip control method according to claim 3 is characterized in that the slope-mass-deceleration diagram of the forklift is obtained by the following steps:

Step 1. Set the empty mass of the forklift to m 0 , the load range to m 1 ~m y , and evenly divide the load range into y-1 segments with a total of y points, namely m 1 ,m 2 ,m 3 …m y-2 ,m y-1 , my . Therefore, the working mass of the forklift is m 0 ,m 1 +m 0 ,m 2 +m 0 ,m 3 +m 0 …m y-2 +m 0 ,m y-1 +m 0 ,m y +m 0 ; the slope value is b%, the unit change difference of the slope value is adjusted to c%, and the upper limit of the slope value is (b+cx)%; the slope-mass-deceleration diagram determines that the number of experimental tests is (y+1)×(x+1);

Step 2: Drive the unloaded forklift up a slope with a gradient value of b% at a reasonable speed v. After going up the slope, the driver immediately releases the accelerator pedal and does not perform any operation on the accelerator pedal and the brake pedal. The speed sensor collects and records the current braking deceleration a10 ; add cargo with a mass of m1 , and the mass of the forklift is ( m0 + m1 ); repeat step b, collect and record the current braking deceleration a10 , and repeat step 4b until the braking decelerations corresponding to different loads at all slope values of b% are collected;

Step 3. Keeping the other conditions unchanged, adjust the slope values to b%, (b+2)%, ..., (b+2x-2)%, (b+2x)% and repeat step 4b to obtain the working mass of the forklift as m 0 , m 1 +m 0 , m 2 +m 0 , m 3 +m 0 ... The corresponding braking deceleration values when my-2 +m 0 ,m y-1 +m 0 ,m y +m 0 are (a 00 ,a 01 ...a 0y-1 ,a 0y ),(a 10 ,a 11 ...a 1y-1 ,a 1y )...(a x0 ,a x1 ...a xy-1 ,a xy );

Step 4. After obtaining the braking deceleration values corresponding to (y+1)×(x+1) different slopes and different working masses, use (m 0 ,b,a 00 );(m 1 ,b+2,a 11 )...(m y-1 ,b+2x-2,a (x-1)(y-1) );(m y ,b+2x,a xy ), these (y+1)×(x+1) sets of data to determine xy planes, and connect the xy planes to obtain the slope-mass-deceleration diagram.
The forklift start-up anti-slope control method according to claim 1 is characterized in that the critical driving force is F t =G sinθ+F f cosθ=mg(sinθ+μcosθ);

Where Ft is the critical driving force, Ff is the friction force, G is the weight of the forklift, and θ is the slope angle where the forklift is located.
The forklift start-up anti-slope control method according to claim 1 is characterized in that the target speed of the engine is obtained by querying the engine universal characteristic curve and the target output torque, and the target output torque is

Wherein Ft is the critical driving force as stated in claim 5, Tfq is the target output torque of the engine; ig is the transmission speed ratio; i0 is the main reducer speed ratio; ηt is the mechanical efficiency of the entire transmission system; and r is the wheel rolling radius.
A method for controlling automatic parking on a slope of a forklift, characterized in that forklift speed information, accelerator pedal information, and slope information of the forklift's current position are obtained, the obtained forklift status information is processed and it is determined whether the forklift meets the automatic parking condition; if the automatic parking condition on the slope is met, the parking brake solenoid valve is turned on for braking, and the forklift automatically parks on the slope.
The method for controlling automatic parking on a slope of a forklift according to claim 8 is characterized in that if the forklift speed is less than 3 km/h, the accelerator pedal is in a zero state, and the slope of the forklift's current position is 3°, and the three judgment conditions are met at the same time, then it is judged that the forklift enters the automatic parking condition on the slope.
A forklift control system for use in any one of claims 1 to 9, characterized in that it comprises

A vehicle speed sensor is installed at the wheel of the forklift to collect vehicle speed information;

A brake pedal signal sensor, which is installed on the brake pedal and is used to collect the driver's operation signal on the brake pedal;

An accelerator pedal switch signal sensor is installed on the accelerator pedal and is used to collect the driver's operation signal on the accelerator pedal;

An engine speed sensor, which is mounted on the engine output shaft and is used to collect engine speed signals;

The vehicle gear position signal sensor is installed on the gear position operating handle to collect vehicle A signal indicating that the vehicle is currently in forward gear, reverse gear or neutral gear;

A slope sensor, which is mounted on the vehicle body and is used to collect a slope signal of the forklift;

A parking brake solenoid valve, wherein the parking brake solenoid valve is a switch valve;

A processor, wherein the input end of the processor is respectively connected to the vehicle speed sensor, the brake pedal signal sensor, the accelerator pedal switch signal sensor, the engine speed sensor, the vehicle gear signal, and the slope sensor, and the output end of the processor is connected to the parking brake solenoid valve.