A heavy commercial vehicle steering driving feeling self-adjusting method and system

Abstract

The application provides a heavy commercial vehicle steering driving feeling self-adjusting method and system, and the method comprises a steering load arbitration adjusting step: when the driver steering meets a steering compensation condition, a current torque value average is obtained; a steering load compensation coefficient is obtained by comparing the current torque value average with a set empty load torque average and a full load torque average; a driver torque corresponding to a current vehicle speed is obtained according to a set basic boost curve, and the product of the driver torque and the steering load compensation coefficient is used as a basic boost for driving feeling adjustment. The application mainly compensates the driver steering force according to the whole vehicle state information, and realizes the low-speed steering sensitivity and high-speed steering stability characteristics.

Description

Technical Field

[0001] This invention relates to the field of commercial vehicle steering adjustment technology, and in particular to a method and system for self-adjusting steering feel in heavy-duty commercial vehicles. Background Technology

[0002] Currently, most heavy-duty commercial vehicles in China use recirculating ball hydraulic steering systems, a relatively mature technology. However, it has significant drawbacks in steering feel, with issues such as heavy steering at stationary positions and a feeling of instability at high speeds directly impacting the driving experience. Due to the limitations of the hydraulic mechanical structure, achieving both light steering at low speeds and stable steering at high speeds is challenging. Electro-hydraulic power steering (EHPS) adds a drive controller and motor actuator to the traditional hydraulic power steering system, allowing the steering assistance to vary with vehicle speed to meet the driving needs of different speeds and road conditions.

[0003] Steering feel calibration typically takes place at a test track under unloaded conditions. It involves subjective adjustments by the OEM's steering calibration engineers, with the steering supplier modifying motor control parameters to achieve various steering styles such as comfort, standard, and sport. The calibrated steering feel parameters are then embedded in the controller, allowing end-users to select different feel options via vehicle communication. However, the steering controller cannot automatically adjust the driving feel based on changes in the overall load of the commercial vehicle. Therefore, a self-adjusting steering feel method is needed. Summary of the Invention

[0004] This invention solves the problem that existing steering controllers cannot adjust the driving feel according to changes in the overall load of commercial vehicles. It proposes a method and system for self-adjusting the steering feel of heavy commercial vehicles, which mainly compensates the driver's steering force based on the overall vehicle status information, thereby achieving sensitive steering at low speeds and stable steering at high speeds.

[0005] To achieve the above objectives, the following technical solution is proposed: A method for self-adjusting steering feel in heavy commercial vehicles, including a steering load arbitration adjustment step: S1, when the driver's steering meets the steering compensation conditions, obtain the current average torque value; S2, the steering load compensation coefficient is obtained by comparing the current average torque value with the set average no-load torque value and average full-load torque value. S3 obtains the driver torque corresponding to the current vehicle speed based on the set basic assist curve, and uses the product of the driver torque and the steering load compensation coefficient as the basic assist for adjusting the driving feel.

[0006] The present invention specifically includes the following steps: S1: Set the steering compensation conditions and determine in real time whether the driver's steering meets the steering compensation conditions. If so, obtain the average current torque value of the commercial vehicle and proceed to S2. Otherwise, continue monitoring. S2, set the average no-load torque value and the average full-load torque value, compare the current average torque value with the average no-load torque value and the average full-load torque value respectively, and obtain the steering load compensation coefficient for self-adjustment of driving feel; S3, Set the basic assist curve. The x-axis of the basic assist curve represents the vehicle speed, and the y-axis represents the driver torque at the corresponding vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed. Use the product of the steering load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel. Basic assist = Basic assist curve output × Load compensation coefficient.

[0007] This invention determines the load change of commercial vehicles based on steering and straight-line driving conditions, and adjusts the driving feel based on the load change to improve driving comfort. It is implemented through software control without the need for additional hardware systems on the basis of the original steering control system.

[0008] Preferably, the present invention further includes a straight-line load arbitration adjustment step: SA, when the driver's straight-line driving meets the straight-line compensation conditions, obtains the current acceleration time of the commercial vehicle; SB is used to obtain the straight-line load compensation coefficient by comparing the current acceleration time of commercial vehicles with the set acceleration time of empty commercial vehicles and the acceleration time of fully loaded commercial vehicles. SC obtains the driver torque corresponding to the current vehicle speed based on the set basic assist curve, and uses the product of the driver torque and the straight-line load compensation coefficient as the basic assist for adjusting the driving feel.

[0009] In addition to the steering load arbitration adjustment step, this invention also includes a straight-line load arbitration adjustment step. The straight-line load arbitration mechanism supplements the steering load arbitration mechanism, mainly calculating the commercial vehicle's acceleration time based on information such as vehicle speed, gear, braking force, throttle opening, and turn signals. The straight-line load arbitration adjustment step specifically includes the following steps: SA, setting the straight-line compensation conditions and determining in real time whether the driver's straight-line movement meets the conditions; if so, obtaining the current commercial vehicle acceleration time and then proceeding to SB; otherwise, continuous monitoring. SB, set the acceleration time of fully loaded commercial vehicles and the acceleration time of unloaded commercial vehicles, compare the current acceleration time of commercial vehicles with the acceleration time of fully loaded commercial vehicles and the acceleration time of unloaded commercial vehicles respectively, and obtain the straight-line load compensation coefficient for self-adjustment of driving feel; SC, set the basic assist curve, where the x-axis of the basic assist curve is the vehicle speed and the y-axis is the driver torque corresponding to the vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed, and use the product of the straight-line load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel.

[0010] As a preferred option, when both the steering compensation condition and the straight-line compensation condition are met, the steering load arbitration adjustment step should be executed first.

[0011] When both straight-line compensation conditions and steering compensation conditions are met simultaneously, the steering load arbitration adjustment step will be executed first. That is, in the event of a conflict between steering load arbitration and straight-line steering arbitration, steering load arbitration shall take precedence.

[0012] Preferably, the steering compensation conditions simultaneously satisfy the following: the steering is within the effective absolute value of the steering wheel angle, the torque change rate is less than a certain threshold, the steering wheel speed is less than a certain threshold, and there are no fault restrictions in the total power assist calculation.

[0013] The steering compensation conditions of this invention include the following four conditions that must be met simultaneously: 1. Steering is within the effective absolute value of the steering wheel angle; 2. The rate of change of torque is less than a certain threshold; 3. The steering wheel rotation speed is less than a certain threshold; 4. Total power calculation has no fault limitations.

[0014] Preferably, the straight-line compensation conditions are simultaneously satisfied as follows: the vehicle reaches the target speed at a specified initial speed, the throttle opening meets a certain threshold or the accelerator pedal opening meets a certain threshold, the engine speed meets a certain threshold, the braking pressure is less than a certain threshold, there is no steering signal and the steering wheel angle is less than a certain threshold.

[0015] The straight-line compensation conditions of the present invention include the following six conditions that must be met simultaneously: 1. The vehicle reaches the target speed at the specified initial speed; 2. The throttle opening or the accelerator pedal opening meets a certain threshold. 3. The engine speed meets a certain threshold; 4. The braking pressure is less than a certain threshold; 5. The steering wheel angle is less than a certain threshold; 6. No turn signal.

[0016] Preferably, the process for obtaining the average no-load torque and the average full-load torque is as follows: Under steering compensation conditions, based on the original steering feel calibration parameters, the torque values ​​at several steering wheel angle points at various vehicle speeds were recorded under both unloaded and fully loaded conditions of the commercial vehicle. The average torque value at each speed breakpoint was calculated to obtain the average unloaded torque value and the average fully loaded torque value.

[0017] The process for obtaining the average no-load torque of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0018] The process for obtaining the average full-load torque value of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0019] Preferably, the process for obtaining the acceleration time of the unloaded commercial vehicle and the acceleration time of the fully loaded commercial vehicle is as follows: Under straight-line compensation conditions, the acceleration time of commercial vehicles is recorded under both unloaded and fully loaded conditions to obtain the acceleration time of unloaded and fully loaded commercial vehicles.

[0020] The process for obtaining the acceleration time of an unloaded commercial vehicle according to the present invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when unloaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the unloaded commercial vehicle.

[0021] The process for obtaining the acceleration time of a fully loaded commercial vehicle according to the present invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when fully loaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the fully loaded commercial vehicle.

[0022] Preferably, step S2 specifically includes the following steps: S21, within the specified vehicle speed range and sampling points, determine whether the current average torque value is less than or equal to the average unloaded torque value. If yes, the steering load compensation coefficient is equal to 1; otherwise, proceed to S22. S22, determine if the current average torque value is less than the average torque value under full load. If so, the steering load compensation coefficient is equal to the ratio of the current average torque value to the average torque value under no-load conditions. If not, the steering load compensation coefficient is equal to the load compensation coefficient limit.

[0023] S2 of the present invention specifically includes the following steps: When the driver's steering meets the steering compensation conditions, the following steps are performed: Within the specified vehicle speed range and sampling points, if the average unloaded torque value < the average current torque value < the average fully loaded torque value, the load compensation coefficient = the average current torque value / the average unloaded torque value; Within the specified vehicle speed range and sampling points, if the current average torque value is less than or equal to the average unloaded torque value, the load compensation coefficient is 1. Within a specified speed range and sampling points, if the current average torque value is greater than or equal to the average torque value under full load, the load compensation coefficient equals the load compensation coefficient limit. The load compensation coefficient limit is calculated as: (Average torque at all speed points under full load) / (Average torque at all speed points under no-load).

[0024] Preferably, the SB specifically includes the following steps: SB1, within the specified speed range, determine whether the current commercial vehicle's acceleration time is less than or equal to the unloaded commercial vehicle's acceleration time. If yes, the straight-line load compensation coefficient is equal to 1; otherwise, proceed to SB2. SB2 determines whether the current acceleration time of the commercial vehicle is less than the acceleration time of the fully loaded commercial vehicle. If so, the straight-line load compensation coefficient is equal to the ratio of the current average torque to the average unloaded torque. If not, the straight-line load compensation coefficient is equal to the load compensation coefficient limit.

[0025] The SB of the present invention specifically includes the following steps: When the driver's straight-ahead movement meets the straight-ahead compensation conditions, the following steps are performed: Within the same specified speed range, if the current commercial vehicle acceleration time is less than or equal to the unloaded commercial vehicle acceleration time, the load compensation coefficient is 1. Within the same specified speed range, if the acceleration time of an unloaded commercial vehicle is less than the current acceleration time of a commercial vehicle, which is less than the acceleration time of a fully loaded commercial vehicle, the load compensation coefficient is equal to the current average torque value / the average unloaded torque value.

[0026] When the current commercial vehicle acceleration time is greater than or equal to the fully loaded commercial vehicle acceleration time, the load compensation coefficient = the load compensation coefficient limit. The load compensation coefficient limit = the average torque at all speed points under full load / the average torque at all speed points under no-load.

[0027] A self-adjusting steering feel system for heavy-duty commercial vehicles, applicable to the aforementioned self-adjusting steering feel method for heavy-duty commercial vehicles, includes a vehicle status information acquisition module and a steering controller. The vehicle status information acquisition module acquires vehicle status information and sends it to the steering controller. The steering controller performs steering load arbitration and straight-line load arbitration based on the vehicle status information to obtain steering load compensation coefficients and straight-line load compensation coefficients. Based on these coefficients, it generates a motor control signal. The motor that adjusts the steering feel generates basic power assist based on the motor control signal.

[0028] The system of this invention includes vehicle status information, vehicle signal processing, vehicle load arbitration, power assist calculation, motor control, and motor, such as... Figure 1 As shown. The vehicle status information mainly includes steering torque / angle, vehicle speed, turn signal, gear position, brake pressure, vehicle attitude sensor signals, etc., providing an important source of information for determining the vehicle's load. Vehicle status signal processing mainly involves parsing the vehicle signals and filtering the necessary signals. Vehicle load arbitration mainly analyzes and makes decisions based on the vehicle signals, classifying the vehicle load as "empty" or "fully loaded," predicting the driver's intention to drive straight or turn, and inputting a load compensation coefficient to the power assist calculation layer. The power assist calculation mainly compensates for the driver's steering force based on the vehicle status information, achieving sensitive steering at low speeds and stable steering at high speeds. The motor control drives the steering motor to execute according to the power assist calculation, thereby adjusting the steering feel. This invention determines the load change of commercial vehicles based on steering and straight-line driving conditions, and adjusts the driving feel based on the load change to improve driving comfort. It is implemented through software control without adding additional hardware to the original steering control system. The steering controller records the average torque at all vehicle speeds under no-load conditions, the average torque at all vehicle speeds under full load conditions, the load compensation coefficient limit, the average torque at all speed cutoff points under full load conditions, the average torque at all speed cutoff points under no-load conditions, the acceleration time of the vehicle under no-load conditions, and the acceleration time of the vehicle under full load conditions. The calibration parameters of this invention include vehicle load arbitration and load-based straight-line acceleration determination. During design, these parameters should be determined based on actual conditions and engineering experience. The load compensation coefficient should be ≥1, and the number of torque and vehicle speed sampling points included in the calculation can be specified.

[0029] The beneficial effects of this invention are: based on the steering and straight-line driving conditions, this invention determines the load change of commercial vehicles, and at the same time, based on the load change of commercial vehicles, it adjusts the driving feel to improve driving comfort. Based on the original steering control system, no additional hardware system is required, and it is achieved through software control. Attached Figure Description

[0030] Figure 1 This is a block diagram of the self-adjusting steering feel system of the present invention; Figure 2 This is a schematic diagram of the working principle of the vehicle load arbitration module of the present invention; Figure 3 This is the basic auxiliary calculation principle diagram of the present invention. Detailed Implementation

[0031] Example 1: This embodiment proposes a method for self-adjusting steering feel in heavy-duty commercial vehicles, referencing... Figure 2 This includes the steering load arbitration adjustment steps: S1: Set the steering compensation conditions and determine in real time whether the driver's steering meets the steering compensation conditions. If so, obtain the average current torque value of the commercial vehicle and proceed to S2. Otherwise, continue monitoring. S2, set the average no-load torque value and the average full-load torque value, and compare the current average torque value with the average no-load torque value and the average full-load torque value respectively to obtain the steering load compensation coefficient used for self-adjustment of driving feel; the process of obtaining the average no-load torque value of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0032] The process for obtaining the average full-load torque value of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0033] S3, Set a basic assist curve. The x-axis of the basic assist curve represents the vehicle speed, and the y-axis represents the driver torque at the corresponding vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed. Use the product of the steering load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel. (Reference) Figure 3 The basic assist is calculated as the output of the basic assist curve multiplied by the load compensation coefficient.

[0034] This invention determines the load change of commercial vehicles based on steering and straight-line driving conditions, and adjusts the driving feel based on the load change to improve driving comfort. It is implemented through software control without the need for additional hardware systems on the basis of the original steering control system.

[0035] In addition to the steering load arbitration adjustment step, this invention also includes a straight-line load arbitration adjustment step. The straight-line load arbitration mechanism supplements the steering load arbitration mechanism, primarily relying on information such as vehicle speed, gear position, braking force, throttle opening, and turn signals to calculate the commercial vehicle's acceleration time. The straight-line load arbitration adjustment step specifically includes the following steps: SA sets the straight-line compensation conditions and determines in real time whether the driver's straight-line movement meets the straight-line compensation conditions. If so, it obtains the current acceleration time of the commercial vehicle and then enters SB. Otherwise, it continues to monitor. SB sets the acceleration time for a fully loaded commercial vehicle and the acceleration time for an unloaded commercial vehicle. It then compares the current acceleration time of the commercial vehicle with both the fully loaded and unloaded acceleration times to obtain the straight-line load compensation coefficient used for self-adjustment of driving feel. The process for obtaining the acceleration time of an unloaded commercial vehicle in this invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when unloaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the unloaded commercial vehicle.

[0036] The process for obtaining the acceleration time of a fully loaded commercial vehicle according to the present invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when fully loaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the fully loaded commercial vehicle.

[0037] SC, set the basic assist curve, where the x-axis of the basic assist curve is the vehicle speed and the y-axis is the driver torque corresponding to the vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed, and use the product of the straight-line load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel.

[0038] When both straight-line compensation conditions and steering compensation conditions are met simultaneously, the steering load arbitration adjustment step will be executed first. That is, in the event of a conflict between steering load arbitration and straight-line steering arbitration, steering load arbitration shall take precedence.

[0039] This embodiment also proposes a self-adjusting system for steering feel in heavy-duty commercial vehicles, applicable to the aforementioned self-adjusting method for steering feel in heavy-duty commercial vehicles. The system includes a steering controller and a vehicle status information acquisition module. The vehicle status information acquisition module collects vehicle status information and transmits it to the steering controller. The steering controller receives the vehicle status information and performs straight-line load arbitration and steering load arbitration based on the information to obtain straight-line load compensation coefficients and steering load compensation coefficients. It then generates a motor control signal based on these coefficients. The motor that adjusts the steering feel generates basic assist based on the motor control signal.

[0040] The system of this invention includes vehicle status information, vehicle signal processing, vehicle load arbitration, power assist calculation, motor control, and motor, such as... Figure 1 As shown. The vehicle status information mainly includes steering torque / angle, vehicle speed, turn signal, gear position, brake pressure, vehicle attitude sensor signals, etc., providing an important source of information for determining the vehicle's load. Vehicle status signal processing mainly involves parsing the vehicle signals and filtering the necessary signals. Vehicle load arbitration mainly analyzes and makes decisions based on the vehicle signals, classifying the vehicle load as "empty" or "fully loaded," predicting the driver's intention to drive straight or turn, and inputting a load compensation coefficient to the power assist calculation layer. The power assist calculation mainly compensates for the driver's steering force based on the vehicle status information, achieving sensitive steering at low speeds and stable steering at high speeds. The motor control drives the steering motor to execute according to the power assist calculation, thereby adjusting the steering feel. This invention determines the load change of commercial vehicles based on steering and straight-line driving conditions, and adjusts the driving feel based on the load change to improve driving comfort. It is implemented through software control without adding additional hardware to the original steering control system. The steering controller records the average torque at all vehicle speeds under no-load conditions, the average torque at all vehicle speeds under full load conditions, the load compensation coefficient limit, the average torque at all speed cutoff points under full load conditions, the average torque at all speed cutoff points under no-load conditions, the acceleration time of the vehicle under no-load conditions, and the acceleration time of the vehicle under full load conditions. The calibration parameters of this invention include vehicle load arbitration and load-based straight-line acceleration determination. During design, these parameters should be determined based on actual conditions and engineering experience. The load compensation coefficient should be ≥1, and the number of torque and vehicle speed sampling points included in the calculation can be specified.

[0041] Example 2: This embodiment improves upon steps S2 and SB of Embodiment 1, proposing a self-adjusting method for steering and driving feel in heavy commercial vehicles. (Refer to...) Figure 2 This includes the steering load arbitration adjustment steps: S1: Set the steering compensation conditions and determine in real time whether the driver's steering meets the steering compensation conditions. If so, obtain the average current torque value of the commercial vehicle and proceed to S2. Otherwise, continue monitoring. S2, set the average no-load torque value and the average full-load torque value, and compare the current average torque value with the average no-load torque value and the average full-load torque value respectively to obtain the steering load compensation coefficient used for self-adjustment of driving feel; the process of obtaining the average no-load torque value of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0042] The process for obtaining the average full-load torque value of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0043] S2 of the present invention specifically includes the following steps: When the driver's steering meets the steering compensation conditions, the following steps are performed: Within the specified vehicle speed range and sampling points, if the average unloaded torque value < the average current torque value < the average fully loaded torque value, the load compensation coefficient = the average current torque value / the average unloaded torque value; Within the specified vehicle speed range and sampling points, if the current average torque value is less than or equal to the average unloaded torque value, the load compensation coefficient is 1. Within a specified speed range and sampling points, if the current average torque value is greater than or equal to the average torque value under full load, the load compensation coefficient equals the load compensation coefficient limit. The load compensation coefficient limit is calculated as: (Average torque at all speed points under full load) / (Average torque at all speed points under no-load).

[0044] S3, Set a basic assist curve. The x-axis of the basic assist curve represents the vehicle speed, and the y-axis represents the driver torque at the corresponding vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed. Use the product of the steering load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel. (Reference) Figure 3 The basic assist is calculated as the output of the basic assist curve multiplied by the load compensation coefficient.

[0045] This invention determines the load change of commercial vehicles based on steering and straight-line driving conditions, and adjusts the driving feel based on the load change to improve driving comfort. It is implemented through software control without the need for additional hardware systems on the basis of the original steering control system.

[0046] In addition to the steering load arbitration adjustment step, this invention also includes a straight-line load arbitration adjustment step. The straight-line load arbitration mechanism supplements the steering load arbitration mechanism, primarily relying on information such as vehicle speed, gear position, braking force, throttle opening, and turn signals to calculate the commercial vehicle's acceleration time. The straight-line load arbitration adjustment step specifically includes the following steps: SA sets the straight-line compensation conditions and determines in real time whether the driver's straight-line movement meets the straight-line compensation conditions. If so, it obtains the current acceleration time of the commercial vehicle and then enters SB. Otherwise, it continues to monitor. SB sets the acceleration time for a fully loaded commercial vehicle and the acceleration time for an unloaded commercial vehicle. It then compares the current acceleration time of the commercial vehicle with both the fully loaded and unloaded acceleration times to obtain the straight-line load compensation coefficient used for self-adjustment of driving feel. The process for obtaining the acceleration time of an unloaded commercial vehicle in this invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when unloaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the unloaded commercial vehicle.

[0047] The process for obtaining the acceleration time of a fully loaded commercial vehicle according to the present invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when fully loaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the fully loaded commercial vehicle.

[0048] The SB of the present invention specifically includes the following steps: When the driver's straight-ahead movement meets the straight-ahead compensation conditions, the following steps are performed: Within the same specified speed range, if the current commercial vehicle acceleration time is less than or equal to the unloaded commercial vehicle acceleration time, the load compensation coefficient is 1. Within the same specified speed range, if the acceleration time of an unloaded commercial vehicle is less than the current acceleration time of a commercial vehicle, which is less than the acceleration time of a fully loaded commercial vehicle, the load compensation coefficient is equal to the current average torque value / the average unloaded torque value.

[0049] When the current commercial vehicle acceleration time is greater than or equal to the fully loaded commercial vehicle acceleration time, the load compensation coefficient = the load compensation coefficient limit. The load compensation coefficient limit = the average torque at all speed points under full load / the average torque at all speed points under no-load.

[0050] SC, set the basic assist curve, where the x-axis of the basic assist curve is the vehicle speed and the y-axis is the driver torque corresponding to the vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed, and use the product of the straight-line load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel.

[0051] When both straight-line compensation conditions and steering compensation conditions are met simultaneously, the steering load arbitration adjustment step will be executed first. That is, in the event of a conflict between steering load arbitration and straight-line steering arbitration, steering load arbitration shall take precedence.

[0052] This embodiment also proposes a self-adjusting system for steering feel in heavy-duty commercial vehicles, applicable to the aforementioned self-adjusting method for steering feel in heavy-duty commercial vehicles. The system includes a steering controller and a vehicle status information acquisition module. The vehicle status information acquisition module collects vehicle status information and transmits it to the steering controller. The steering controller receives the vehicle status information and performs straight-line load arbitration and steering load arbitration based on the information to obtain straight-line load compensation coefficients and steering load compensation coefficients. It then generates a motor control signal based on these coefficients. The motor that adjusts the steering feel generates basic assist based on the motor control signal.

[0053] The system of this invention includes vehicle status information, vehicle signal processing, vehicle load arbitration, power assist calculation, motor control, and motor, such as... Figure 1 As shown. The vehicle status information mainly includes steering torque / angle, vehicle speed, turn signal, gear position, brake pressure, vehicle attitude sensor signals, etc., providing an important source of information for determining the vehicle's load. Vehicle status signal processing mainly involves parsing the vehicle signals and filtering the necessary signals. Vehicle load arbitration mainly analyzes and makes decisions based on the vehicle signals, classifying the vehicle load as "empty" or "fully loaded," predicting the driver's intention to drive straight or turn, and inputting a load compensation coefficient to the power assist calculation layer. The power assist calculation mainly compensates for the driver's steering force based on the vehicle status information, achieving sensitive steering at low speeds and stable steering at high speeds. The motor control drives the steering motor to execute according to the power assist calculation, thereby adjusting the steering feel. This invention determines the load change of commercial vehicles based on steering and straight-line driving conditions, and adjusts the driving feel based on the load change to improve driving comfort. It is implemented through software control without adding additional hardware to the original steering control system. The steering controller records the average torque at all vehicle speeds under no-load conditions, the average torque at all vehicle speeds under full load conditions, the load compensation coefficient limit, the average torque at all speed cutoff points under full load conditions, the average torque at all speed cutoff points under no-load conditions, the acceleration time of the vehicle under no-load conditions, and the acceleration time of the vehicle under full load conditions. The calibration parameters of this invention include vehicle load arbitration and load-based straight-line acceleration determination. During design, these parameters should be determined based on actual conditions and engineering experience. The load compensation coefficient should be ≥1, and the number of torque and vehicle speed sampling points included in the calculation can be specified.

[0054] Example 3: This embodiment, based on Embodiments 1 and 2, defines the steering compensation conditions and straight-line compensation conditions, and proposes a method for self-adjusting the steering driving feel of heavy commercial vehicles. (Refer to...) Figure 2 This includes the steering load arbitration adjustment steps: S1: Set the steering compensation conditions and determine in real time whether the driver's steering meets the steering compensation conditions. If so, obtain the average current torque value of the commercial vehicle and proceed to S2. Otherwise, continue monitoring. The steering compensation conditions of this invention include the following four conditions that must be met simultaneously: 1. Steering is within the effective absolute value of the steering wheel angle; 2. The rate of change of torque is less than a certain threshold; 3. The steering wheel rotation speed is less than a certain threshold; 4. Total power calculation has no fault limitations.

[0055] S2, set the average no-load torque value and the average full-load torque value, and compare the current average torque value with the average no-load torque value and the average full-load torque value respectively to obtain the steering load compensation coefficient used for self-adjustment of driving feel; the process of obtaining the average no-load torque value of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0056] The process for obtaining the average full-load torque value of the present invention is as follows: First, preliminary preparations are made. Based on the original steering feel calibration parameters, the steering compensation conditions are met when the commercial vehicle is unloaded. Then, the vehicle speed is recorded. This invention selects a speed range of 0-80 km / h and selects several sampling points to record the torque value at the steering wheel angle. At the same time, the average torque value at each speed cutoff point is calculated, and the average torque at all speed cutoff points under unloaded conditions is also calculated.

[0057] S2 of the present invention specifically includes the following steps: When the driver's steering meets the steering compensation conditions, the following steps are performed: Within the specified vehicle speed range and sampling points, if the average unloaded torque value < the average current torque value < the average fully loaded torque value, the load compensation coefficient = the average current torque value / the average unloaded torque value; Within the specified vehicle speed range and sampling points, if the current average torque value is less than or equal to the average unloaded torque value, the load compensation coefficient is 1. Within a specified speed range and sampling points, if the current average torque value is greater than or equal to the average torque value under full load, the load compensation coefficient equals the load compensation coefficient limit. The load compensation coefficient limit is calculated as: (Average torque at all speed points under full load) / (Average torque at all speed points under no-load).

[0058] S3, Set a basic assist curve. The x-axis of the basic assist curve represents the vehicle speed, and the y-axis represents the driver torque at the corresponding vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed. Use the product of the steering load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel. (Reference) Figure 3 The basic assist is calculated as the output of the basic assist curve multiplied by the load compensation coefficient.

[0059] This invention determines the load change of commercial vehicles based on steering and straight-line driving conditions, and adjusts the driving feel based on the load change to improve driving comfort. It is implemented through software control without the need for additional hardware systems on the basis of the original steering control system.

[0060] In addition to the steering load arbitration adjustment step, this invention also includes a straight-line load arbitration adjustment step. The straight-line load arbitration mechanism supplements the steering load arbitration mechanism, primarily relying on information such as vehicle speed, gear position, braking force, throttle opening, and turn signals to calculate the commercial vehicle's acceleration time. The straight-line load arbitration adjustment step specifically includes the following steps: SA sets the straight-line compensation conditions and determines in real time whether the driver's straight-line movement meets the straight-line compensation conditions. If so, it obtains the current acceleration time of the commercial vehicle and then enters SB. Otherwise, it continues to monitor. The straight-line compensation conditions of the present invention include the following six conditions that must be met simultaneously: 1. The vehicle reaches the target speed at the specified initial speed; 2. The throttle opening or the accelerator pedal opening meets a certain threshold. 3. The engine speed meets a certain threshold; 4. The braking pressure is less than a certain threshold; 5. The steering wheel angle is less than a certain threshold; 6. No turn signal.

[0061] SB sets the acceleration time for a fully loaded commercial vehicle and the acceleration time for an unloaded commercial vehicle. It then compares the current acceleration time of the commercial vehicle with both the fully loaded and unloaded acceleration times to obtain the straight-line load compensation coefficient used for self-adjustment of driving feel. The process for obtaining the acceleration time of an unloaded commercial vehicle in this invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when unloaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the unloaded commercial vehicle.

[0062] The process for obtaining the acceleration time of a fully loaded commercial vehicle according to the present invention is as follows: First, preliminary preparations are made to ensure that the commercial vehicle meets the straight-line compensation conditions when fully loaded, and the vehicle acceleration time is recorded to obtain the acceleration time of the fully loaded commercial vehicle.

[0063] The SB of the present invention specifically includes the following steps: When the driver's straight-ahead movement meets the straight-ahead compensation conditions, the following steps are performed: Within the same specified speed range, if the current commercial vehicle acceleration time is less than or equal to the unloaded commercial vehicle acceleration time, the load compensation coefficient is 1. Within the same specified speed range, if the acceleration time of an unloaded commercial vehicle is less than the current acceleration time of a commercial vehicle, which is less than the acceleration time of a fully loaded commercial vehicle, the load compensation coefficient is equal to the current average torque value / the average unloaded torque value.

[0064] When the current commercial vehicle acceleration time is greater than or equal to the fully loaded commercial vehicle acceleration time, the load compensation coefficient = the load compensation coefficient limit. The load compensation coefficient limit = the average torque at all speed points under full load / the average torque at all speed points under no-load.

[0065] SC, set the basic assist curve, where the x-axis of the basic assist curve is the vehicle speed and the y-axis is the driver torque corresponding to the vehicle speed. Obtain the driver torque corresponding to the set basic assist curve at the current vehicle speed, and use the product of the straight-line load compensation coefficient and the driver torque as the basic assist for adjusting the driving feel.

[0066] When both straight-line compensation conditions and steering compensation conditions are met simultaneously, the steering load arbitration adjustment step will be executed first. That is, in the event of a conflict between steering load arbitration and straight-line steering arbitration, steering load arbitration shall take precedence.

Claims

1. A method for self-adjusting steering feel in heavy-duty commercial vehicles, characterized in that, Including steering Load Arbitration Adjustment Steps: S1, when the driver's steering meets the steering compensation conditions, obtain the current average torque value; S2, the steering load compensation coefficient is obtained by comparing the current average torque value with the set average no-load torque value and average full-load torque value. S3 obtains the driver torque corresponding to the current vehicle speed based on the set basic assist curve, and uses the product of the driver torque and the steering load compensation coefficient as the basic assist for adjusting the driving feel. It also includes the straight-line load arbitration adjustment procedure: SA, when the driver's straight-line driving meets the straight-line compensation conditions, obtains the current acceleration time of the commercial vehicle; SB is used to obtain the straight-line load compensation coefficient by comparing the current acceleration time of commercial vehicles with the set acceleration time of empty commercial vehicles and the acceleration time of fully loaded commercial vehicles. SC obtains the driver torque corresponding to the current vehicle speed based on the set basic assist curve, and uses the product of the driver torque and the straight-line load compensation coefficient as the basic assist for adjusting the driving feel.

2. The method for self-adjusting steering feel of a heavy commercial vehicle according to claim 1, characterized in that, When both the steering compensation condition and the straight-line compensation condition are met, the steering load arbitration adjustment step shall be executed first.

3. A method for self-adjusting steering feel of a heavy commercial vehicle according to any one of claims 1-2, characterized in that, The steering compensation conditions are simultaneously satisfied as follows: the steering is within the absolute value of the effective steering wheel angle, the torque change rate is less than a certain threshold, the steering wheel speed is less than a certain threshold, and there are no fault restrictions in the total power assist calculation.

4. A method for self-adjusting steering feel of a heavy commercial vehicle according to claim 1 or 2, characterized in that, The straight-line compensation conditions are simultaneously met as follows: the vehicle reaches the target speed at a specified initial speed, the throttle opening meets a certain threshold or the accelerator pedal opening meets a certain threshold, the engine speed meets a certain threshold, the braking pressure is less than a certain threshold, there is no steering signal and the steering wheel angle is less than a certain threshold.

5. The method for self-adjusting steering feel of a heavy commercial vehicle according to claim 1, characterized in that, The process for obtaining the average no-load torque and the average full-load torque is as follows: Under steering compensation conditions, based on the original steering feel calibration parameters, the torque values ​​at several steering wheel angle points at various vehicle speeds were recorded under both unloaded and fully loaded conditions of the commercial vehicle. The average torque value at each speed breakpoint was calculated to obtain the average unloaded torque value and the average fully loaded torque value.

6. The method for self-adjusting steering feel of a heavy commercial vehicle according to claim 1, characterized in that, The process for obtaining the acceleration time of the unloaded commercial vehicle and the acceleration time of the fully loaded commercial vehicle is as follows: Under straight-line compensation conditions, the acceleration time of commercial vehicles is recorded under both unloaded and fully loaded conditions to obtain the acceleration time of unloaded and fully loaded commercial vehicles.

7. The method for self-adjusting steering feel of a heavy commercial vehicle according to claim 1, characterized in that, S2 specifically includes the following steps: S21, within the specified vehicle speed range and sampling points, determine whether the current average torque value is less than or equal to the average unloaded torque value. If yes, the steering load compensation coefficient is equal to 1; otherwise, proceed to S22. S22, determine if the current average torque value is less than the average torque value under full load. If so, the steering load compensation coefficient is equal to the ratio of the current average torque value to the average torque value under no-load conditions. If not, the steering load compensation coefficient is equal to the load compensation coefficient limit.

8. The method for self-adjusting steering feel of a heavy commercial vehicle according to claim 7, characterized in that, The SB specifically includes the following steps: SB1, within the specified speed range, determine whether the current commercial vehicle's acceleration time is less than or equal to the unloaded commercial vehicle's acceleration time. If yes, the straight-line load compensation coefficient is equal to 1; otherwise, proceed to SB2. SB2 determines whether the current acceleration time of the commercial vehicle is less than the acceleration time of the fully loaded commercial vehicle. If so, the straight-line load compensation coefficient is equal to the ratio of the current average torque to the average unloaded torque. If not, the straight-line load compensation coefficient is equal to the load compensation coefficient limit.

9. A self-adjusting system for steering feel in heavy-duty commercial vehicles, applicable to the self-adjusting method for steering feel in heavy-duty commercial vehicles as described in any one of claims 1-2, characterized in that, It includes a vehicle status information acquisition module and a steering controller. The vehicle status information acquisition module collects vehicle status information and sends it to the steering controller. The steering controller performs steering load arbitration and straight-line load arbitration based on the vehicle status information to obtain steering load compensation coefficient and straight-line load compensation coefficient. Based on the steering load compensation coefficient and straight-line load compensation coefficient, it generates a motor control signal. The motor that adjusts the steering feel generates basic power assist based on the motor control signal.

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