Method and system for adaptive control of hill start assist function for automatic commercial vehicles

Abstract

The application discloses a kind of methods and systems for the adaptive control of automatic shift commercial vehicle's hill start assist function, the main design concept of the application is, by reading current speed information, gradient information, accelerator brake pedal information, transmission gear information and hill start assist function working condition information, whether to activate or exit hill start assist function is automatically identified, in addition to taking into account different load weight conditions, without artificial judgment activation or release, without manual operation (for example, open hill start assist switch), vehicle ignition can be normally started driving, and hill start assist function is adaptively activated and exited, and the disadvantages of flat road hill start assist function being activated are avoided, so it is more in line with actual use, so that flat road start is more smooth, more intelligent, accurate and comfortable.

Description

Technical Field

[0001] This invention relates to the field of commercial vehicle control technology, and in particular to an adaptive control method and system for hill start assist function of automatic transmission commercial vehicles. Background Technology

[0002] When starting and stopping on a slope, improper operation by the driver can easily cause the vehicle to roll backwards, especially in heavy commercial vehicle applications. The safety risks are even greater when the vehicle is fully loaded. Therefore, hill start assist functions are now widely used in commercial vehicles.

[0003] With the application of automatic transmission (AMT) products in commercial vehicles, the overall vehicle intelligence has been upgraded. However, most automatic transmission commercial vehicles continue the hill start method of traditional manual transmission vehicles without adding a dedicated hill start adaptive response mechanism. The existing hill start assist function of commercial vehicles is mostly manually controlled to be turned on, activated, and deactivated. In actual use, this manual operation is quite cumbersome, and the corresponding function is basically achieved by controlling the braking time. For example, when the vehicle is parked on a slope, the driver first starts the engine, then presses the hill start switch and closes the manual control valve, so that the compressed air from the air tank reaches the two-position three-way solenoid valve. Then the transmission controller sends the received engine signal, hill start switch signal, braking signal, and start status signal to the hill start controller. The hill start controller then calculates the current slope resistance to be overcome based on the longitudinal dynamics of the vehicle and issues a command to energize the two-position three-way solenoid valve, switching the vehicle from service braking to hill start assist braking.

[0004] This method still requires manual judgment and operation to activate and deactivate the hill start assist function. Furthermore, because it cannot calculate the slope in real time, it cannot accurately determine the required traction force or the timing for deactivating the hill start assist function. This not only results in poor convenience but also insufficient intelligence, making it similar to the traditional manual transmission operation method. It fails to simplify the operation, leading some users to avoid using the hill start assist function, which has a significant impact on safety and the lifespan of the vehicle's clutch. Summary of the Invention

[0005] In view of the above, the present invention aims to provide an adaptive control method and system for hill start assist function in automatic transmission commercial vehicles, thereby solving the problem of inconvenient operation of existing hill start assist functions.

[0006] The technical solution adopted in this invention is as follows:

[0007] Firstly, an adaptive control method for hill start assist function in automatic transmission commercial vehicles, comprising:

[0008] After the vehicle is started, the actual working environment is monitored in real time; the actual working environment includes vehicle speed, road slope, pedal status, gear information and hill start assist function status.

[0009] Based on the actual working environment and automatic transmission operating conditions, determine whether the first preset condition for automatically opening the hill start assist function is met, and determine whether the second preset condition for prematurely closing the hill start assist function is met, and send the corresponding control command.

[0010] The control command triggers the execution module to open or close, thereby activating or deactivating the ramp assist function.

[0011] In at least one of the possible implementations, the first preset condition includes at least the following: the vehicle speed is zero, the brake pedal is depressed, the vehicle is in a non-neutral state, and the road surface slope is greater than a preset slope threshold.

[0012] In at least one of the possible implementations, the second preset condition includes at least the following: the brake and accelerator have not been pressed for a preset duration, the speed of the transmission output shaft is higher than a preset speed value, and the torque of the transmission input shaft is higher than a preset torque value.

[0013] In at least one of the possible implementations, the preset speed value and the preset torque value are calibrated and calculated by the automatic transmission control system based on the vehicle's load mass, so that the traction force exceeds a preset proportion of the vehicle's weight component in the slope direction.

[0014] Secondly, an adaptive control system for hill start assist function in an automatic transmission commercial vehicle, comprising:

[0015] The environmental perception module is used to detect the actual working environment in real time after the vehicle is started; the actual working environment includes vehicle speed, road slope, pedal status, gear information and hill start assist function status.

[0016] The decision calculation module is used to determine, based on the actual working environment and the automatic transmission operating conditions, whether the first preset condition for automatically opening the hill start assist function is met, and whether the second preset condition for prematurely closing the hill start assist function is met, and to send corresponding control commands.

[0017] The control module is used to trigger the execution module to open or close according to the control command to activate or deactivate the ramp assist function. The execution module includes an electric brake.

[0018] In at least one possible implementation, the environment sensing module includes:

[0019] At least one of the following is used to sense vehicle speed: vehicle speed sensor, wheel speed sensor, or dashcam;

[0020] At least one of the following slope sensors for sensing road surface slope;

[0021] At least one of the following is used to sense the pedal status: accelerator pedal and brake pedal travel sensor;

[0022] At least one of the following gear position sensors for sensing gear position information; and,

[0023] At least one of the following: a physical or virtual switch for the ramp assist function used to sense the status of the ramp assist function.

[0024] In at least one possible implementation, the slope sensor is integrated into the automatic transmission.

[0025] In at least one of the possible implementations, the decision calculation module includes at least one of the following: an independent controller, an engine ECU, and a transmission TCU.

[0026] In at least one of the possible implementations, the control module includes: an anti-lock braking system or an electronic braking system.

[0027] In at least one of the possible implementations, the electric brake is an electro-pneumatic brake.

[0028] The main design concept of this invention is to automatically identify whether to activate or deactivate the hill start assist function by reading current vehicle speed information, slope information, accelerator and brake pedal information, transmission gear information, and hill start assist function operating status information. In addition to taking into account different load weight conditions, there is no need for manual judgment to activate or deactivate, nor is there any need for manual operation (such as turning on the hill start assist switch). The vehicle can start driving normally after ignition, and the hill start assist function will automatically activate and deactivate. It also avoids the drawbacks of the hill start assist function being activated on flat roads, thus being more in line with actual use, making starting on flat roads smoother, and more intelligent, precise and comfortable.

[0029] Furthermore, this invention can be built on the basis of vehicle CAN communication, and obtain information such as brake pedal position in real time through electrical signals, with timely and accurate response, effectively avoiding control delay; in addition, it utilizes mature technologies such as EBS / ABS that are already widely used in commercial vehicles, to achieve faster activation and deactivation response of the vehicle brakes, more convenient system application, and stronger operability.

[0030] Furthermore, compared to the requirement that the slope angle sensor be installed independently on the vehicle body or chassis, the present invention allows and preferably integrates the slope sensor inside the transmission, which is more conducive to space saving and protection of the slope sensor. Attached Figure Description

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to the accompanying drawings, wherein:

[0032] Figure 1 A flowchart of an adaptive control method for hill start assist function for automatic transmission commercial vehicles provided in an embodiment of the present invention;

[0033] Figure 2 This is a block diagram of an adaptive control system for hill start assist function for automatic transmission commercial vehicles, provided in an embodiment of the present invention. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0035] The methods and systems involved in this invention can be embodied in the following comprehensive scheme, in combination with Figure 1 , Figure 2 Indication:

[0036] Environmental perception module: After the vehicle is started, the actual working environment is detected in real time. The actual working environment includes vehicle speed (which may involve at least one of the following: vehicle speed sensor, wheel speed sensor, driving recorder), road slope (which may involve slope sensor: used to identify the road tilt angle, which can be integrated into the transmission in actual operation), pedal status (which may involve accelerator pedal and brake pedal travel sensor, brake fluid pressure sensor), gear information (which may involve gear sensor) and hill start assist function status (which may involve hill start assist function physical switch or virtual switch, and ABS / EBS, etc.).

[0037] Decision calculation module (controller, which can be an independent controller, engine ECU or transmission TCU in actual operation): Based on the actual working environment and automatic transmission operating conditions, determine whether the first preset condition for automatically opening the hill start assist function is met, and determine whether the second preset condition for early deactivation of the hill start assist function is met, and send the corresponding control commands.

[0038] Specifically, the first preset condition includes at least the following: the vehicle speed is zero, the brake pedal is depressed, the vehicle is in a non-neutral state, and the road slope is greater than the preset slope threshold.

[0039] The second preset conditions include at least the following: neither the brake nor the accelerator has been depressed for a preset duration (e.g., 3 seconds), the transmission output shaft speed is higher than a preset speed value (e.g., 100 rpm), and the transmission input shaft torque is higher than a preset torque value (e.g., 200 Nm). Based on this, it can also be pointed out that, in actual operation, the preset speed and torque values ​​of the transmission can be calibrated and calculated by the automatic transmission control system based on the vehicle's load capacity. That is, the aforementioned settings only need to satisfy the preset proportion that the traction force exceeds the component of gravity in the slope direction.

[0040] Continuing from the previous text, finally, the control module (anti-lock braking system or electronic braking system, ABS / EBS): triggers the execution module (brake, commercial vehicles mostly use electronic air brakes) to open or close according to the control command to activate or deactivate the hill start assist function.

[0041] Furthermore, based on the aforementioned embodiments, we can further illustrate with specific examples:

[0042] The ramp assist switch can provide a Hill Hold Switch signal (switch status signal), where 0 indicates the switch is off and 1 indicates the switch is on.

[0043] ABS / EBS can provide a Hill Holder Mode signal (operating mode signal), where 0 indicates that the hill assist function is off and 1 indicates that the hill assist function is on;

[0044] The ECU / TCU provides a Ready for Brake Release signal (preset condition judgment result signal), where 0 indicates that the condition is met and 1 indicates that the condition is not met.

[0045] Therefore, here is a reference for the implementation of the hill start assist adaptive control system: When a commercial vehicle is stopped on a slope (assuming the slope is greater than the set value), the driver presses the brake and releases the handbrake. At this time, the Ready for Brake Release signal provided by the transmission TCU changes from 1 to 0; and the Hill Hold Switch is detected to be in state 1 (i.e., the switch is on by default). After the ABS / EBS receives Ready for Brake Release = 0, the Hill HolderMode signal changes from the initial 0 to 1. At this time, the ABS / EBS will activate the vehicle's brakes, and the vehicle will be automatically stopped and locked to prevent it from rolling.

[0046] Afterwards, if the driver releases the brake and does not press the accelerator, this state will remain for 3 seconds before Ready for Brake Release changes from 0 to 1; or if the driver releases the brake and presses the accelerator, and the vehicle's speed and torque at the transmission output shaft are both higher than the set values ​​(this period is less than 3 seconds), Ready for Brake Release changes from 0 to 1.

[0047] After the ABS / EBS receives the Ready for Brake Release = 1, the Hill Holder Mode status changes from 1 to 0. At this time, the ABS / EBS will close the vehicle's brakes, and the vehicle can then be driven normally.

[0048] In summary, the main design concept of this invention is to automatically identify whether to activate or deactivate the hill start assist function by reading current vehicle speed information, slope information, accelerator and brake pedal information, transmission gear information, and hill start assist function operating status information. In addition to taking into account different load weight conditions, there is no need for manual judgment to activate or deactivate, nor is there any need for manual operation (such as turning on the hill start assist switch). The vehicle can start driving normally after ignition, and the hill start assist function will adaptively activate and deactivate, avoiding the drawbacks of the hill start assist function being activated on flat roads. Therefore, it is more in line with actual use, making starting on flat roads smoother, and more intelligent, precise and comfortable.

[0049] In this embodiment of the invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0050] The above description of the structure, features, and effects of the present invention is based on the embodiments shown in the figures. However, the above are only preferred embodiments of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred methods can be reasonably combined and matched by those skilled in the art to form a variety of equivalent solutions without departing from or changing the design concept and technical effects of the present invention. Therefore, the present invention is not limited to the scope of implementation shown in the figures. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments, that do not exceed the spirit covered by the specification and figures, should be within the protection scope of the present invention.

Claims

1. An adaptive control method for hill start assist function in automatic transmission commercial vehicles, characterized in that, include: After the vehicle is started, the actual working environment is monitored in real time; the actual working environment includes vehicle speed, road slope, pedal status, gear information and hill start assist function status. Based on the actual working environment and automatic transmission operating conditions, determine whether the first preset condition for automatically activating the hill start assist function is met, and determine whether the second preset condition for prematurely deactivating the hill start assist function is met, and send corresponding control commands; wherein, the automatic transmission operating conditions include: preset condition judgment result signal provided by the TCU; Furthermore, the first preset condition includes at least the preset condition judgment result signal, representing a change from no condition to condition; the second preset condition includes at least the preset condition judgment result signal, representing a change from condition to no condition. The control command triggers the execution module to open or close to activate or deactivate the ramp assist function, specifically including: the anti-lock braking system or electronic braking system triggers the brake to open or close according to the control command to activate or deactivate the ramp assist function. The specific execution process of the adaptive control method is as follows: The ramp assist switch provides a Hill Hold Switch signal, where 0 indicates the switch is off and 1 indicates the switch is on. ABS / EBS provides a Hill Holder Mode signal, where 0 indicates that the hill assist function is off and 1 indicates that the hill assist function is on. The ECU / TCU provides a Ready for Brake Release signal, where 0 indicates that the condition is met and 1 indicates that the condition is not met. When a commercial vehicle is stopped on a slope and the driver has applied the brakes and released the handbrake, the Ready for BrakeRelease signal changes from 1 to 0. At this time, after the Hill Hold Switch is detected to be in state 1 and the ABS / EBS receives Ready for BrakeRelease=0, the Hill Holder Mode changes from 0 to 1. At this time, the vehicle's brakes are activated, and the vehicle is automatically stopped and locked. If the driver releases the brake and does not press the accelerator, Ready for Brake Release will change from 0 to 1 after the state is maintained for the predetermined duration; or, if the driver releases the brake and presses the accelerator, and the vehicle's speed and torque at the transmission output shaft are both higher than the preset values, Ready for Brake Release will change from 0 to 1. Once the ABS / EBS receives the message "Ready for Brake Release=1", Hill Holder Mode changes from 1 to 0, at which point the vehicle brakes are closed to allow the vehicle to drive normally.

2. The adaptive control method for hill start assist function in automatic transmission commercial vehicles according to claim 1, characterized in that, The preset speed and preset torque values ​​are calculated by the automatic transmission control system based on the vehicle's load mass to ensure that the traction force exceeds the preset proportion of the vehicle's weight component in the slope direction.

3. An adaptive control system for hill start assist function of an automatic transmission commercial vehicle implementing the adaptive control method of claim 1 or 2, characterized in that, include: The environmental perception module is used to detect the actual working environment in real time after the vehicle is started; the actual working environment includes vehicle speed, road slope, pedal status, gear information and hill start assist function status. The decision calculation module is used to determine, based on the actual working environment and the automatic transmission operating conditions, whether the first preset condition for automatically opening the hill start assist function is met, and whether the second preset condition for prematurely closing the hill start assist function is met, and to send corresponding control commands; wherein, the automatic transmission operating conditions include: the preset condition judgment result signal provided by the TCU; Furthermore, the first preset condition includes at least the preset condition judgment result signal, representing a change from no condition to condition; the second preset condition includes at least the preset condition judgment result signal, representing a change from condition to no condition. The control module is used to trigger the execution module to open or close according to the control command to activate or deactivate the ramp assist function. The execution module includes an electric brake, specifically including: the brake is triggered to open or close by the anti-lock braking system or electronic braking system according to the control command to activate or deactivate the ramp assist function.

4. The hill start assist adaptive control system for automatic transmission commercial vehicles according to claim 3, characterized in that, The environment sensing module includes: At least one of the following is used to sense vehicle speed: vehicle speed sensor, wheel speed sensor, or dashcam; At least one of the following slope sensors for sensing road surface slope; At least one of the following is used to sense the pedal status: accelerator pedal and brake pedal travel sensor; At least one of the following gear position sensors for sensing gear position information; and, At least one of the following: a physical or virtual switch for the ramp assist function used to sense the status of the ramp assist function.

5. The hill-start assist adaptive control system for automatic transmission commercial vehicles according to claim 4, characterized in that, The slope sensor is integrated into the automatic transmission.

6. The hill-start assist adaptive control system for automatic transmission commercial vehicles according to claim 3, characterized in that, The decision calculation module includes at least one of the following: an independent controller, an engine ECU, or a transmission TCU.

7. The hill-start assist adaptive control system for automatic transmission commercial vehicles according to any one of claims 3 to 6, characterized in that, The electric brake is an electro-pneumatic brake.

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