Torque-based steering control method and industrial vehicle

Abstract

The application discloses a torque-based steering control method and an industrial vehicle, and the method comprises the following steps: detecting whether a direction pull rod, an acceleration pedal or a brake pedal is triggered, if yes, setting a rotating speed of a hydraulic motor as a low idle speed of the hydraulic motor, and detecting whether a hydraulic operating rod is triggered, if not, acquiring a torque of the hydraulic motor; if the torque of the hydraulic motor is greater than or equal to a preset torque, setting the rotating speed of the hydraulic motor as a high idle speed of the hydraulic motor; the high idle speed of the hydraulic motor is equal to a sum of the low idle speed of the hydraulic motor and a preset increment rotating speed; the low idle speed of the hydraulic motor is equal to an idle speed set when the direction pull rod, the acceleration pedal or the brake pedal is triggered. The application utilizes torque feedback of the hydraulic motor to determine whether steering is performed, so as to improve the rotating speed of the hydraulic motor and achieve the purpose of steering assistance. Since a steering sensor does not need to be additionally arranged on a steering column or a rated rotating speed needs not to be set, the application has low cost, low energy consumption and does not affect micro-motion operation.

Description

Technical Field

[0001] This invention relates to the field of industrial vehicle technology, and in particular to a torque-based steering control method and an industrial vehicle. Background Technology

[0002] Industrial vehicles are motor vehicles that are powered to move, push, tow, lift, stack, or place various goods. Many industrial vehicles, such as forklifts, have their working devices, accessories, and steering systems all driven by the same hydraulic system.

[0003] Steering control of existing forklifts is mainly achieved through the following two methods:

[0004] 1. Install a steering sensor on the steering column. When steering, the speed of the hydraulic pump motor is proportional to the speed of the steering column, and the flow rate can be provided as needed.

[0005] 2. The hydraulic pump motor is set to a rated speed, which can meet the steering flow requirements for both slow and fast rotation.

[0006] Method 1, if equipped with a steering sensor, can achieve good steering performance, but it is expensive, mainly due to the cost of custom steering column and sensor. Method 2, if the pump motor is given a relatively high rated speed, can also meet steering requirements, but it will result in poor micro-motion and increased energy consumption. Furthermore, the speed requirement gradually decreases as the forklift speed increases; if a high rated speed is applied, there is a potential risk of rollover at high speeds. Summary of the Invention

[0007] The main objective of this invention is to overcome the aforementioned deficiencies in the prior art and propose a torque-based steering control method and industrial vehicle. This method utilizes the torque feedback of a hydraulic motor to determine whether steering is in progress, thereby increasing the speed of the hydraulic motor to achieve steering assistance. Since it does not require the installation of a steering sensor on the steering column or the setting of a rated speed, it is low in cost and energy consumption and does not affect micro-motion control.

[0008] The present invention adopts the following technical solution:

[0009] On the one hand, a torque-based steering control method includes:

[0010] Check if the steering lever, accelerator pedal, or brake pedal is triggered. If so, set the speed of the hydraulic motor to the low idle speed of the hydraulic motor and check if the hydraulic control lever is triggered. If the hydraulic control lever is not triggered, obtain the torque of the hydraulic motor.

[0011] If the torque of the hydraulic motor is greater than or equal to the preset torque, the speed of the hydraulic motor is set to the high idle speed of the hydraulic motor; the high idle speed of the hydraulic motor is equal to the sum of the low idle speed of the hydraulic motor and the preset incremental speed; the low idle speed of the hydraulic motor is equal to the idle speed set when the steering lever, accelerator pedal or brake pedal is triggered.

[0012] Preferably, if the torque of the hydraulic motor is greater than or equal to a preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the method further includes:

[0013] Start or reset the hydraulic motor high idle speed timer with the set timing;

[0014] When the torque of the hydraulic motor is detected to be less than the preset torque, it is determined whether the high idle speed timer of the hydraulic motor has reached its set time. If it has not reached its set time, the speed of the hydraulic motor is maintained at the high idle speed. If it has reached its set time, the speed of the hydraulic motor is set to the low idle speed.

[0015] Preferably, if the torque of the hydraulic motor is greater than or equal to a preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the method further includes:

[0016] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0017] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, it is determined whether the timing time of the high idle speed timer of the hydraulic motor and the timing time of the low idle speed timer of the hydraulic motor have both been reached. If both have been reached, the speed of the hydraulic motor is set to 0.

[0018] Preferably, if the torque of the hydraulic motor is greater than or equal to a preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the method further includes:

[0019] Within a preset time period, the speed of the hydraulic motor is gradually increased to adjust it to the high idle speed.

[0020] Preferably, the torque-based steering control method further includes:

[0021] Detect whether the steering lever, accelerator pedal, or brake pedal is triggered. If so, set the speed of the hydraulic motor to the low idle speed of the hydraulic motor. Detect whether the hydraulic joystick is triggered. If the hydraulic joystick is triggered, obtain the hydraulic motor speed required by the joystick and set the hydraulic motor speed to the maximum value between the low idle speed of the hydraulic motor and the hydraulic motor speed required by the joystick.

[0022] Preferably, after detecting whether the steering lever, accelerator pedal, or brake pedal is triggered, and if so, setting the speed of the hydraulic motor to the low idle speed of the hydraulic motor, the method further includes:

[0023] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0024] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, determine whether the low idle speed timer of the hydraulic motor has reached its time limit. If it has, set the speed of the hydraulic motor to 0.

[0025] Preferably, after setting the hydraulic motor speed to the maximum value between the hydraulic motor's low idle speed and the hydraulic motor speed required by the control lever, the method further includes:

[0026] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0027] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, determine whether the low idle speed timer of the hydraulic motor has reached its time limit. If it has, set the speed of the hydraulic motor to 0.

[0028] Preferably, the torque-based steering control method further includes:

[0029] Check if the steering lever, accelerator pedal, or brake pedal is triggered. If none of them are triggered, check if the hydraulic joystick is triggered. If the hydraulic joystick is triggered, obtain the required hydraulic motor speed for the joystick and set the hydraulic motor speed to the required hydraulic motor speed for the joystick.

[0030] Preferably, after setting the hydraulic motor speed to the speed required by the control lever, the method further includes:

[0031] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0032] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, it is determined whether the low idle speed timer of the hydraulic motor has reached its time limit. If all of them have reached their time limit, the speed of the hydraulic motor is set to 0.

[0033] On the other hand, an industrial vehicle includes a vehicle body, a controller, and a hydraulic motor, wherein the controller uses the torque-based steering control method described above to adjust the speed of the hydraulic motor.

[0034] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention provides a torque-based steering control method, which uses the torque feedback of the hydraulic motor to determine whether steering is in progress, thereby increasing the speed of the hydraulic motor to achieve steering assistance. Since it is not necessary to install a steering sensor on the steering column or set a rated speed, it solves the problems of steering jamming and noise, while having low cost and energy consumption, and does not affect micro-motion operation.

[0036] (2) When the steering lever, accelerator pedal, or brake pedal is triggered and the control lever (used for hydraulic operation, such as lifting / tilting) is not operated, the pump motor is given a low idle speed (adjustable). When the steering wheel is operated (steering), if the torque is detected to be greater than the preset torque, the speed is increased to a high idle speed. This satisfies the problem of high flow demand when the forklift is turning quickly, and prevents the steering from becoming heavy due to insufficient flow. The specific speed increase and acceleration time are adjustable. When the torque is detected to be less than the preset torque, the speed is adjusted to a low idle speed after a delay (via a timer). If the steering lever, accelerator pedal, brake pedal, and control lever are not triggered, the speed is set to zero after a delay (via a timer) to prevent frequent actions caused by micro-motion. The above-mentioned idle time, idle speed value, torque, and motor response time (acceleration time) can be adjusted according to different vehicle models, thus achieving a consistent user experience.

[0037] (3) When the steering lever, accelerator pedal and brake pedal are not triggered and the hydraulic control lever is triggered, if the hydraulic control lever is triggered, the hydraulic motor speed is set to the hydraulic motor speed required by the control lever; when the steering lever, accelerator pedal or brake pedal is triggered and the hydraulic control lever is also triggered, the hydraulic motor speed is set to the maximum value between the low idle speed of the hydraulic motor and the hydraulic motor speed required by the control lever, so as to ensure the performance of hydraulic operation such as lifting / tilting without affecting the micro-motion function. Attached Figure Description

[0038] Figure 1 A simplified flowchart illustrating the method of this embodiment of the invention where the direction lever, accelerator pedal, or brake pedal is triggered but the hydraulic control lever is not triggered.

[0039] Figure 2 A simplified flowchart illustrating the method of this embodiment of the invention where the direction lever, accelerator pedal, or brake pedal is triggered and the hydraulic control lever is triggered.

[0040] Figure 3 A simplified flowchart illustrating the method of this embodiment of the invention where the direction lever, accelerator pedal, or brake pedal is not triggered but the hydraulic control lever is triggered.

[0041] Figure 4 This is a general flowchart of the method according to an embodiment of the present invention;

[0042] Figure 5 This is a structural block diagram of an industrial vehicle according to an embodiment of the present invention. Detailed Implementation

[0043] The present invention will be further described below through specific embodiments.

[0044] See Figure 1 As shown, the present invention provides a torque-based steering control method, comprising:

[0045] Check if the steering lever, accelerator pedal, or brake pedal is triggered. If so, set the speed of the hydraulic motor to the low idle speed of the hydraulic motor and check if the hydraulic control lever is triggered. If the hydraulic control lever is not triggered, obtain the torque of the hydraulic motor.

[0046] If the torque of the hydraulic motor is greater than or equal to the preset torque, the speed of the hydraulic motor is set to the high idle speed of the hydraulic motor; the high idle speed of the hydraulic motor is equal to the sum of the low idle speed of the hydraulic motor and the preset incremental speed; the low idle speed of the hydraulic motor is equal to the idle speed set when the steering lever, accelerator pedal or brake pedal is triggered.

[0047] In this embodiment, the execution entity of the above method is the controller. The specific type of controller used is not specifically limited in this embodiment. Figure 1 As can be seen, the above steps can begin after the controller detects that the car key has been turned on and that someone is in the seat. Figure 1 In the diagram, C1 represents the required hydraulic motor speed for the joystick; C2 represents the hydraulic motor speed; A represents the low idle speed of the hydraulic motor; B represents the high idle speed of the hydraulic motor, which is equal to A+N, where N represents the adjustable preset incremental speed; K1 represents the response time of the hydraulic motor speed change, which is an adjustable value adapted to different vehicle models; β represents the feedback torque value of the hydraulic motor, which is an adjustable value and varies for different vehicle models; Timer1 represents the low idle speed A timer for the hydraulic motor; Timer2 represents the high idle speed B timer for the hydraulic motor; N1 represents the low idle speed A time value for the hydraulic motor, which is an adjustable value; N2 represents the high idle speed B time value for the hydraulic motor, which is an adjustable value.

[0048] Furthermore, if the torque of the hydraulic motor is greater than or equal to the preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the following is also included:

[0049] Start or reset the hydraulic motor high idle speed timer with the set timing;

[0050] When the torque of the hydraulic motor is detected to be less than the preset torque, it is determined whether the high idle speed timer of the hydraulic motor has reached its set time. If it has not reached its set time, the speed of the hydraulic motor is maintained at the high idle speed. If it has reached its set time, the speed of the hydraulic motor is set to the low idle speed.

[0051] It should be noted that "start or reset" as mentioned here or later means: if the timer (including the hydraulic motor low idle timer / hydraulic motor high idle timer) has been started before, it will be reset; if the timer has not been started before, it will be started. In this embodiment, the timer with the set timing can be set and started before steering control is executed (or after the key is turned on and someone is in the seat), or the timer with the set timing can be started during the execution of steering control.

[0052] In addition, the timer can be an ascending timer (e.g., a 2-second timer starts counting down from 0, and when it reaches 2 seconds, the timer is considered to have reached its end) or a countdown timer (e.g., a 2-second timer starts counting down from 2 seconds, and when it reaches 0, the timer is considered to have reached its end).

[0053] Furthermore, if the torque of the hydraulic motor is greater than or equal to the preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the following is also included:

[0054] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0055] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, it is determined whether the timing time of the high idle speed timer of the hydraulic motor and the timing time of the low idle speed timer of the hydraulic motor have both been reached. If both have been reached, the speed of the hydraulic motor is set to 0.

[0056] In addition, see Figure 1 As shown in this embodiment, after detecting a trigger on the steering lever, accelerator pedal, or brake pedal, and setting the speed of the hydraulic motor to low idle speed, the low idle speed timer of the hydraulic motor can be started or reset. If the torque of the hydraulic motor is subsequently detected to be greater than or equal to the preset torque, and the speed of the hydraulic motor is set to high idle speed, the low idle speed timer of the hydraulic motor is reset and the timing starts again.

[0057] Specifically, the system checks whether the steering lever, accelerator pedal, or brake pedal is activated. If so, it sets the hydraulic motor speed to its low idle speed. The process also includes:

[0058] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0059] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, determine whether the low idle speed timer of the hydraulic motor has reached its time limit. If it has, set the speed of the hydraulic motor to 0.

[0060] Furthermore, if the torque of the hydraulic motor is greater than or equal to the preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the following is also included:

[0061] Within a preset time period, the speed of the hydraulic motor is gradually increased to the high idle speed of the hydraulic motor to ensure that the speed of the hydraulic motor does not change suddenly, thus preventing performance instability and wear.

[0062] In summary, the torque-based steering control method of this embodiment uses the torque feedback of the hydraulic motor to determine whether steering is in progress, thereby increasing the speed of the hydraulic motor to achieve steering assistance. Since it does not require the addition of a steering sensor to the steering column or the setting of a rated speed, it solves the problems of steering jamming and noise while having lower cost and energy consumption, and does not affect micro-motion control.

[0063] Specifically, when the steering lever (controlling forward or backward direction), accelerator pedal, or brake pedal is triggered, and no control lever (used for hydraulic operations, such as lifting / tilting) is operated, the pump motor is given a low idle speed (adjustable). When the steering wheel is operated (steering), if the torque is detected to be greater than the preset torque, the speed increases to a high idle speed. The specific speed increase magnitude and acceleration time are adjustable. If the torque is detected to be less than the preset torque, the speed is adjusted to a low idle speed after a delay (via a timer). If the steering lever, accelerator pedal, brake pedal, and control lever are all not triggered, the speed is reset to zero after a delay (via a timer) to prevent frequent actions caused by micro-motion manipulation. The above-mentioned idle time, idle speed value, torque, and motor response time (acceleration time) can be adjusted according to different vehicle models, thus achieving a consistent user experience.

[0064] See Figure 2 As shown, the torque-based steering control method in this embodiment further includes:

[0065] Detect whether the steering lever, accelerator pedal, or brake pedal is triggered. If so, set the speed of the hydraulic motor to the low idle speed of the hydraulic motor. Detect whether the hydraulic joystick is triggered. If the hydraulic joystick is triggered, obtain the hydraulic motor speed required by the joystick and set the hydraulic motor speed to the maximum value between the low idle speed of the hydraulic motor and the hydraulic motor speed required by the joystick.

[0066] Furthermore, after setting the hydraulic motor speed to the maximum of the hydraulic motor's low idle speed and the hydraulic motor speed required by the joystick, it also includes:

[0067] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0068] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, determine whether the low idle speed timer of the hydraulic motor has reached its time limit. If it has, set the speed of the hydraulic motor to 0.

[0069] from Figure 2 It can be seen that if the hydraulic motor low idle speed timer has been started or reset after the hydraulic motor speed is set to the low idle speed, then after the hydraulic motor speed is set to the maximum value between the hydraulic motor low idle speed and the hydraulic motor speed required by the control lever, the hydraulic motor low idle speed timer will be reset and the timing will be restarted.

[0070] See Figure 3 As shown, the torque-based steering control method further includes:

[0071] Check if the steering lever, accelerator pedal, or brake pedal is triggered. If none of them are triggered, check if the hydraulic joystick is triggered. If the hydraulic joystick is triggered, obtain the required hydraulic motor speed for the joystick and set the hydraulic motor speed to the required hydraulic motor speed for the joystick.

[0072] Similarly, in this method, after setting the hydraulic motor speed to the required hydraulic motor speed for the control lever, the following steps are also included:

[0073] Start or reset the low idle speed timer of the hydraulic motor with the set timing time;

[0074] If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, it is determined whether the low idle speed timer of the hydraulic motor has reached its time limit. If all of them have reached their time limit, the speed of the hydraulic motor is set to 0.

[0075] See Figure 4 As shown, the above three flowcharts are combined. In addition, it also includes a process in which the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, and a process in which the steering lever, accelerator pedal or brake pedal are triggered, the hydraulic control lever is not triggered, and the torque of the hydraulic motor is less than the preset torque.

[0076] Figure 2 , Figure 3 and Figure 4 The meanings of each parameter are the same as those in the previous text. Figure 1 .

[0077] See Figure 5 As shown, the present invention provides an industrial vehicle, including a vehicle body 50, a controller 51, and a hydraulic motor 52. The controller 51 uses the torque-based steering control method described above to adjust the speed of the hydraulic motor 52.

[0078] The above are merely specific embodiments of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

Claims

1. A torque-based steering control method, characterized in that, include: The system detects whether the steering lever, accelerator pedal, or brake pedal is triggered. If so, it sets the hydraulic motor speed to the low idle speed and checks whether the hydraulic joystick is triggered. If the hydraulic joystick is not triggered, it acquires the torque of the hydraulic motor. If the torque of the hydraulic motor is greater than or equal to a preset torque, it sets the hydraulic motor speed to the high idle speed. The high idle speed of the hydraulic motor is equal to the sum of the low idle speed of the hydraulic motor and the preset incremental speed. The low idle speed of the hydraulic motor is equal to the idle speed set when the steering lever, accelerator pedal, or brake pedal is triggered. If the hydraulic joystick is triggered, it acquires the hydraulic motor speed required by the joystick and sets the hydraulic motor speed to the maximum value between the low idle speed and the hydraulic motor speed required by the joystick. If the steering lever, accelerator pedal, or brake pedal are not triggered, but the hydraulic joystick is triggered, the required hydraulic motor speed for the joystick is obtained, and the hydraulic motor speed is set to the required hydraulic motor speed for the joystick.

2. The torque-based steering control method according to claim 1, characterized in that, If the torque of the hydraulic motor is greater than or equal to the preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the following is also included: Start or reset the hydraulic motor high idle speed timer with the set timing; When the torque of the hydraulic motor is detected to be less than the preset torque, it is determined whether the high idle speed timer of the hydraulic motor has reached its set time. If it has not reached its set time, the speed of the hydraulic motor is maintained at the high idle speed. If it has reached its set time, the speed of the hydraulic motor is set to the low idle speed.

3. The torque-based steering control method according to claim 2, characterized in that, If the torque of the hydraulic motor is greater than or equal to the preset torque, after setting the speed of the hydraulic motor to the high idle speed of the hydraulic motor, the following is also included: Start or reset the low idle speed timer of the hydraulic motor with the set timing time; If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, it is determined whether the timing time of the high idle speed timer of the hydraulic motor and the timing time of the low idle speed timer of the hydraulic motor have both been reached. If both have been reached, the speed of the hydraulic motor is set to 0.

4. The torque-based steering control method according to claim 1, characterized in that, If the torque of the hydraulic motor is greater than or equal to the preset torque, the speed of the hydraulic motor is set to the high idle speed of the hydraulic motor, specifically including: Within a preset time period, the speed of the hydraulic motor is gradually increased to adjust it to the high idle speed.

5. The torque-based steering control method according to claim 1, characterized in that, After detecting whether the steering lever, accelerator pedal, or brake pedal is triggered, and if so, setting the hydraulic motor speed to the low idle speed, the process also includes: Start or reset the low idle speed timer of the hydraulic motor with the set timing time; If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, determine whether the low idle speed timer of the hydraulic motor has reached its time limit. If it has, set the speed of the hydraulic motor to 0.

6. The torque-based steering control method according to claim 1, characterized in that, After setting the hydraulic motor speed to the maximum of the hydraulic motor's low idle speed and the hydraulic motor speed required by the joystick, the following steps are also included: Start or reset the low idle speed timer of the hydraulic motor with the set timing time; If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, determine whether the low idle speed timer of the hydraulic motor has reached its time limit. If it has, set the speed of the hydraulic motor to 0.

7. The torque-based steering control method according to claim 1, characterized in that, After setting the hydraulic motor speed to the required speed for the control lever, the following steps are also included: Start or reset the low idle speed timer of the hydraulic motor with the set timing time; If the torque of the hydraulic motor is detected to be less than the preset torque, and the steering lever, accelerator pedal, brake pedal and hydraulic control lever are not triggered, it is determined whether the low idle speed timer of the hydraulic motor has reached its time limit. If all of them have reached their time limit, the speed of the hydraulic motor is set to 0.

8. An industrial vehicle, comprising a vehicle body, a controller, and a hydraulic motor, characterized in that, The controller uses the torque-based steering control method as described in any one of claims 1 to 7 to adjust the speed of the hydraulic motor.

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