Steering control system and method for small-circuit commercial vehicle

Abstract

The present application relates to the technical field of vehicle steering control, and discloses a small-turn commercial vehicle steering control system and method thereof. The system includes: an acquisition module for acquiring steering input parameters; an adjustment module for adjusting the transmission ratio; a calculation module for calculating the auxiliary steering torque; an operation module for obtaining the optimal transmission ratio; a compensation module for efficiency compensation; and a control module for controlling the number of steering turns, and each module is electrically connected in sequence to form a closed-loop control structure. The present application reduces the number of steering wheel turns and improves the convenience of steering operation while ensuring the output torque of the commercial vehicle steering system.

Description

Technical Field

[0001] The present application relates to the field of vehicle steering control, and in particular to a steering control system and method for a small-turn commercial vehicle. Background Art

[0002] There are significant differences between commercial vehicle steering systems and passenger vehicle steering systems. Traditional commercial vehicles usually require greater steering output torque due to the need to cope with heavy loads and complex road conditions. In order to meet this requirement, commercial vehicle steering systems generally adopt a larger transmission ratio design, which amplifies the steering input torque through a mechanical transmission structure to provide sufficient steering output torque. Currently, commercial vehicle steering systems on the market mainly include hydraulic power steering systems, electro-hydraulic power steering systems and electric power steering systems. Among them, electric power steering systems have gradually become a development trend due to their advantages such as energy saving, environmental protection, and precise control.

[0003] However, existing commercial vehicle steering systems generally have the problem of too large a transmission ratio. Although the excessive transmission ratio meets the demand for steering output torque, it also leads to too many steering circles for the entire vehicle. Especially in the case of turning around on the spot or turning at a large angle, the driver needs to turn the steering wheel multiple times to complete the steering operation. This not only reduces the steering sensitivity and operating efficiency, but also easily causes driver fatigue. With the development of new energy commercial vehicles and the trend of younger truck practitioners, the traditional large-circle steering method can no longer meet the market's new demand for driving experience. Summary of the invention

[0004] The present application provides a small-turn commercial vehicle steering control system and method thereof, which are used to reduce the number of steering wheel steering turns and improve the convenience of steering operation while ensuring the output torque of the commercial vehicle steering system.

[0005] In a first aspect, the present application provides a steering control system for a small-circuit commercial vehicle, the steering control system for a small-circuit commercial vehicle comprising:

[0006] The acquisition module is used to acquire and process the current input torque T and the number of steering turns R through the electronic control unit according to the target number of steering wheel turns set by the user, and obtain a multi-dimensional steering input parameter set;

[0007] an adjustment module, the adjustment module being electrically connected to the acquisition module and configured to adaptively adjust the mechanical recirculating ball transmission ratio based on the multi-dimensional steering input parameter set to obtain a first adjustment coefficient, and dynamically adjust the worm gear transmission ratio to obtain a second adjustment coefficient;

[0008] a calculation module, the calculation module being electrically connected to the adjustment module and configured to calculate the auxiliary steering torque output by the motor in real time by using the first adjustment coefficient and the second adjustment coefficient to obtain a motor output control signal;

[0009] An operation module, the operation module is electrically connected to the calculation module, and is used to perform a dynamic matching operation on the mechanical circulating ball transmission ratio and the worm gear transmission ratio according to the motor output control signal to obtain an optimal transmission ratio combination;

[0010] A compensation module, which is electrically connected to the calculation module and is used to perform real-time compensation calculation on the worm gear transmission efficiency and the mechanical circulating ball efficiency according to the optimal transmission ratio combination to obtain an efficiency compensation coefficient;

[0011] A control module is electrically connected to the compensation module and is used to perform closed-loop optimization calculations on system parameters based on the efficiency compensation coefficient to obtain a steering control instruction, and control the number of steering wheel rotations within a preset range through the steering control instruction.

[0012] In a first embodiment of the first aspect, an acquisition module is used to: receive a steering wheel target circle value set by a user through a human-computer interaction interface; divide a steering wheel steering input signal into time series data blocks according to a sampling frequency; use a multidimensional torque sensor in an electronic control unit to perform real-time sampling of a current input torque T to generate a steering input torque sampling sequence; use a displacement sensing unit in an electronic control unit to perform high-frequency sampling of a current number of steering circles R to form a steering circle original data stream; process the steering circle original data stream by differential operation to calculate the steering circle change rate and change acceleration of adjacent sampling points respectively; perform data fusion based on the steering wheel target circle value, the steering input torque sampling sequence, the steering circle original data stream, the circle change rate and the circle change acceleration to construct a steering state feature vector; and use a Kalman filter to remove noise from the steering state feature vector to obtain the multidimensional steering input parameter set.

[0013] In a second embodiment of the first aspect, the adjustment module is used to: analyze the stress state of the double-row asymmetric circulating ball structure according to the angular acceleration data in the multi-dimensional steering input parameter set to generate circulating ball load distribution data; calculate the contact angle change of the mechanical circulating ball according to the circulating ball load distribution data to obtain the transmission ratio change parameter; use the transmission ratio change parameter to compensate the mechanical circulating ball transmission ratio to obtain the mechanical circulating ball transmission ratio adjustment amount; convert the mechanical circulating ball transmission ratio adjustment amount into the first adjustment coefficient; extract the steering angle data and angular velocity data from the multi-dimensional steering input parameter set to establish a transmission characteristic curve of a variable pitch worm gear mechanism; calculate the position of the meshing contact point of the variable pitch worm gear mechanism according to the transmission characteristic curve to generate pitch change data; use the pitch change data to perform compensation calculation on the transmission ratio to be processed to form a transmission ratio correction amount to be processed; dynamically adjust the transmission ratio correction amount to be processed to obtain the second adjustment coefficient.

[0014] In a third embodiment of the first aspect, a calculation module is used to: combine the first adjustment coefficient and the second adjustment coefficient to form transmission ratio characteristic data; perform normalization calculation processing on the transmission ratio characteristic data to generate a torque calculation reference value; use the torque calculation reference value to calculate the basic motor torque to obtain a basic motor torque value; perform data product operation on the basic motor torque value with the mechanical circulating ball transmission ratio and the worm gear transmission ratio to obtain an initial value of the motor output auxiliary steering torque; perform correction operation on the initial value of the motor output auxiliary steering torque through a deep fuzzy adaptive controller to obtain the motor output auxiliary steering torque; establish a control quantity mapping relationship based on the motor output auxiliary steering torque to generate the motor output control signal.

[0015] In a fourth embodiment of the first aspect, the operation module is used to: extract the torque control quantity and the angle control quantity from the motor output control signal to construct a transmission ratio constraint function; use the transmission ratio constraint function to define the variation range of the mechanical circulating ball transmission ratio and the worm gear transmission ratio to obtain a transmission ratio adjustment interval; discretize the mechanical circulating ball transmission ratio and the worm gear transmission ratio according to the transmission ratio adjustment interval to generate a transmission ratio combination sequence; calculate the torque transfer characteristics according to the transmission ratio combination sequence to obtain torque distribution ratio data; screen the transmission ratio data pairs that meet the constant output torque condition from the torque distribution ratio data to construct a transmission ratio optimization data set; calculate the steering input-output angle ratio of the transmission ratio optimization data set, and select the transmission ratio combination whose ratio meets the reduction requirement as the optimal transmission ratio combination.

[0016] In a fifth embodiment of the first aspect, a compensation module is used to: extract the circulating ball working parameters and the worm gear working parameters from the optimal transmission ratio combination to generate transmission mechanism operating status data; collect temperature sensor signals based on the transmission mechanism operating status data to obtain temperature distribution characteristic quantities; use the temperature distribution characteristic quantities to calculate the circulating ball friction coefficient and the worm gear friction coefficient to obtain mechanism friction loss data; calculate the mechanical circulating ball efficiency and the worm gear transmission efficiency based on the mechanism friction loss data to obtain efficiency characteristic parameters; construct a temperature-efficiency correlation function based on the efficiency characteristic parameters to generate an efficiency compensation demand; convert the efficiency compensation demand into the efficiency compensation coefficient for correcting the motor output torque.

[0017] In a sixth implementation of the first aspect, the control module includes:

[0018] A compensation unit, used for compensating the steering system operating parameters according to the efficiency compensation coefficient to generate steering characteristic compensation data;

[0019] A comparison unit, used for comparing and calculating the steering characteristic compensation data with the actual steering state data to obtain a steering characteristic error amount;

[0020] A correction unit, used for performing a closed-loop correction operation on the system parameters according to the steering characteristic error amount to obtain an optimized amount of the system parameters;

[0021] A calculation unit, used to calculate the steering control amount using the system parameter optimization amount to obtain basic steering control data;

[0022] A generating unit, configured to calculate the number of steering wheel rotations according to the basic steering control data and generate a number of rotation control parameter;

[0023] The conversion unit is used to convert the rotation number control parameter into the steering control instruction, so as to control the steering wheel rotation number within a preset range.

[0024] In a seventh embodiment of the first aspect, the calculation unit is specifically used to: extract torque optimization parameters and angle optimization parameters from the system parameter optimization quantity to generate a dual-channel control quantity; calculate the torque response coefficient based on the dual-channel control quantity to obtain a torque compensation quantity; perform nonlinear processing on the torque compensation quantity to obtain a damping correction coefficient; use the damping correction coefficient to adjust and calculate the steering feedback force to form a steering control reference value; determine the steering assist characteristic curve from the steering control reference value to obtain an assist compensation quantity; perform data synthesis on the assist compensation quantity and the steering control reference value to generate the basic steering control data.

[0025] In an eighth embodiment of the first aspect, the generating unit is specifically used to: extract the rotation angle data and the rotation speed data from the basic steering control data to form steering wheel motion characteristic data; use the steering wheel motion characteristic data to calculate the angle increment in a single steering process to obtain the change in number of turns; perform cumulative operations on the change in number of turns to obtain the actual number of steering wheel rotations; compare the actual number of steering wheel rotations with the steering limit data to generate a number of turns deviation value; perform compensation calculation on the steering torque distribution according to the number of turns deviation value to obtain the number of turns correction value; construct an angle constraint condition through the number of turns correction value to generate the number of turns control parameter.

[0026] In a second aspect, the present application provides a steering control method for a commercial vehicle with a small number of circles, and the steering control method for a commercial vehicle with a small number of circles comprises:

[0027] According to the target number of steering wheel turns set by the user, the electronic control unit collects and processes the current input torque T and the number of steering turns R to obtain a multi-dimensional steering input parameter set;

[0028] Based on the multi-dimensional steering input parameter set, the mechanical recirculating ball transmission ratio is adaptively adjusted to obtain a first adjustment coefficient, and the worm gear transmission ratio is dynamically adjusted to obtain a second adjustment coefficient;

[0029] Using the first adjustment coefficient and the second adjustment coefficient, the auxiliary steering torque output by the motor is calculated in real time to obtain a motor output control signal;

[0030] According to the motor output control signal, a dynamic matching operation is performed on the mechanical circulating ball transmission ratio and the worm gear transmission ratio to obtain an optimal transmission ratio combination;

[0031] According to the optimal transmission ratio combination, real-time compensation calculation is performed on the worm gear transmission efficiency and the mechanical circulating ball efficiency to obtain an efficiency compensation coefficient;

[0032] Based on the efficiency compensation coefficient, a closed-loop optimization operation is performed on the system parameters to obtain a steering control instruction, and the number of steering wheel rotations is controlled within a preset range through the steering control instruction.

[0033] In the technical solution provided by the present application, the present invention collects and processes the steering input torque and steering angle through an acquisition module to obtain a multi-dimensional steering input parameter set including angular velocity and angular acceleration, thereby realizing comprehensive perception of the steering state; the adjustment module dynamically adjusts the pending transmission ratio of the variable pitch worm gear mechanism and the mechanical circulating ball transmission ratio of the double-row asymmetric circulating ball structure to obtain two adjustment coefficients, thereby realizing real-time optimization of the transmission ratio; the calculation module inputs the adjustment coefficient into the deep fuzzy adaptive controller, and calculates the motor output auxiliary steering torque according to the product of the basic motor torque and the transmission ratio, thereby ensuring precise control of the steering assist; the operation module obtains the optimal transmission ratio combination under constant output torque through dynamic matching operation of the coordinated transmission ratio control unit, thereby reducing the ratio of the steering input angle to the output angle; the compensation module uses the temperature-efficiency mapping model to perform real-time compensation for the transmission efficiency, and corrects the motor output torque through the efficiency compensation coefficient, thereby ensuring the stability of the system under different working conditions; the control module performs closed-loop optimization operation on the system parameters, generates precise steering control instructions, and realizes effective control of the number of steering wheel rotations. Through multi-stage transmission ratio optimization and real-time compensation control, the entire system significantly reduces the number of steering wheel turns without affecting the steering output torque, while maintaining the smoothness and controllability of the steering operation, improving the control convenience of the commercial vehicle steering system. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0035] Figure 1 This is a schematic diagram of an embodiment of a steering control system for a commercial vehicle with a small number of turns in the embodiment of the present application;

[0036] Figure 2 This is a schematic diagram of the structure of the control module in the embodiment of the present application;

[0037] Figure 3 This is a schematic diagram of an embodiment of the steering control method for a commercial vehicle with a small number of turns in the embodiment of the present application. DETAILED DESCRIPTION

[0038] The embodiment of the present application provides a small-circle commercial vehicle steering control system and method thereof. The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0039] For ease of understanding, the specific process of the embodiment of the present application is described below. Figure 1 , an embodiment of a steering control system for a commercial vehicle with a small number of turns in the present application includes:

[0040] The acquisition module 101 is used to acquire and process the current input torque T and the number of steering turns R through the electronic control unit according to the target number of steering wheel turns set by the user, so as to obtain a multi-dimensional steering input parameter set;

[0041] The adjustment module 102 is electrically connected to the acquisition module and is used to adaptively adjust the mechanical recirculating ball transmission ratio based on the multi-dimensional steering input parameter set to obtain a first adjustment coefficient, and dynamically adjust the worm gear transmission ratio to obtain a second adjustment coefficient;

[0042] A calculation module 103, which is electrically connected to the adjustment module and is used to calculate the auxiliary steering torque output by the motor in real time using the first adjustment coefficient and the second adjustment coefficient to obtain a motor output control signal;

[0043] The operation module 104 is electrically connected to the calculation module and is used to perform dynamic matching operation on the mechanical circulating ball transmission ratio and the worm gear transmission ratio according to the motor output control signal to obtain the optimal transmission ratio combination;

[0044] The compensation module 105 is electrically connected to the calculation module and is used to perform real-time compensation calculation on the worm gear transmission efficiency and the mechanical circulating ball efficiency according to the optimal transmission ratio combination to obtain the efficiency compensation coefficient;

[0045] The control module 106 is electrically connected to the compensation module and is used to perform closed-loop optimization calculations on system parameters based on the efficiency compensation coefficient to obtain a steering control instruction, and control the number of steering wheel rotations within a preset range through the steering control instruction.

[0046] Specifically, the acquisition module 101 receives the setting of the target number of steering wheel turns and collects the steering input signal. The strain gauge set in the multi-dimensional torque sensor produces a change in resistance value when it is deformed by force. The strain signal is converted into a voltage signal through a Wheatstone bridge circuit, and then amplified and filtered by a signal conditioning circuit to form a steering input torque sampling sequence. The displacement sensing unit uses a Hall sensor to obtain the rotation angle of the steering wheel by detecting the position change of the permanent magnet. The sampling frequency is set at 1000Hz and converted into a steering angle raw data stream. The differential operation unit calculates adjacent sampling points, and the angle difference between adjacent sampling points is divided by the sampling time interval to obtain the angular velocity, and the rate of change of the angular velocity is the angular acceleration. These data are de-noised by the Kalman filter to form a multi-dimensional steering input parameter set including torque, angle, angular velocity and angular acceleration. After receiving the multi-dimensional steering input parameter set, the adjustment module 102 controls the variable pitch worm gear mechanism and the double-row asymmetric recirculating ball structure respectively. The recirculating balls in the double-row asymmetric recirculating ball structure are arranged in double rows asymmetrically. The force state is analyzed according to the angular acceleration data, and the load distribution of the recirculating balls is calculated. The contact angle between the recirculating ball and the raceway will change with the load, thereby affecting the mechanical recirculating ball transmission ratio. After calculating the contact angle change, the transmission ratio change parameter is obtained, and the first adjustment coefficient is obtained. At the same time, the worm pitch of the variable pitch worm gear mechanism gradually changes along the axial direction, the pitch in the middle section is small, and the pitch at both ends gradually increases. The transmission characteristic curve is established by extracting the steering angle data and angular velocity data. The meshing contact point position of the worm gear is determined according to the steering angle data, and the pitch value of the current working point is calculated. The difference with the reference pitch is the pitch change data. The worm gear transmission ratio is determined by the pitch. The pitch change data is used to correct the worm gear transmission ratio and convert it into the second adjustment coefficient.

[0047] The calculation module 103 combines the first adjustment coefficient and the second adjustment coefficient to form a complete transmission ratio characteristic data. The transmission ratio characteristic data is normalized and mapped to a numerical range between 0 and 1 as a reference value for torque calculation. The deep fuzzy adaptive controller adopts a five-layer deep neural network structure, the input layer receives the normalized transmission ratio characteristic data, the hidden layer performs reasoning operations through fuzzy rules, and the output layer generates the motor output auxiliary steering torque. The product of the transmission ratio to be processed, the mechanical circulating ball transmission ratio and the basic motor torque is used as the initial torque value, and then corrected by the deep fuzzy adaptive controller to obtain the motor output auxiliary steering torque. The controller establishes a mapping relationship between the torque and the motor control parameters, and outputs the corresponding motor output control signal. The operation module 104 constructs a transmission ratio constraint function according to the torque control amount and the angle control amount in the motor output control signal. The constraint function defines the range of variation of the transmission ratio to be processed and the mechanical circulating ball transmission ratio to ensure that the total transmission ratio remains within a reasonable range. Discrete sampling of the transmission ratio is performed within the constraint range to generate several groups of transmission ratio combinations. Calculate the torque transfer characteristics under each transmission ratio combination, including static transmission ratio and dynamic response characteristics, and obtain the torque distribution ratio data. Filter out the transmission ratio data pairs that meet the constant output torque condition, that is, the combinations where the output torque fluctuation is within the allowable range. Finally, calculate the steering input-output angle ratio corresponding to these combinations, and select the combination that can significantly reduce this ratio as the optimal transmission ratio combination.

[0048] The compensation module 105 extracts the working parameters of the worm gear and the recirculating ball from the optimal transmission ratio combination, and establishes a temperature-efficiency mapping relationship in combination with the temperature data of each component collected by the temperature sensor. By analyzing the influence of temperature on the friction coefficient, the actual transmission efficiency of the worm gear and the recirculating ball is calculated. The friction loss data of the mechanism reflects the efficiency loss caused by temperature change, and the efficiency characteristic parameters are generated accordingly. The compensation module constructs a temperature-efficiency correlation function based on the efficiency characteristic parameters, calculates the efficiency compensation coefficient, and is used to correct the motor output torque in real time to ensure that the steering system can maintain stable output characteristics under different temperature conditions. The control module 106 includes multiple functional units: the compensation unit uses the efficiency compensation coefficient to compensate the steering system operating parameters; the comparison unit compares the compensated parameters with the actual steering state; the correction unit performs closed-loop correction according to the error; the calculation unit generates basic steering control data; the generation unit calculates the number of steering wheel rotations; and the conversion unit outputs the steering control command. The entire control process forms a closed-loop structure, and through real-time parameter adjustment and compensation calculation, it ensures that the number of steering wheel rotations is always kept within a reasonable range, which not only meets the torque requirements of commercial vehicle steering, but also improves the driver's control experience.

[0049] In the embodiment of the present application, the steering input torque and steering angle are collected and processed by the acquisition module to obtain a multi-dimensional steering input parameter set including angular velocity and angular acceleration, thereby realizing comprehensive perception of the steering state; the pending transmission ratio of the variable pitch worm gear mechanism and the mechanical circulating ball transmission ratio of the double-row asymmetric circulating ball structure are dynamically adjusted by the adjustment module to obtain two adjustment coefficients, thereby realizing real-time optimization of the transmission ratio; the adjustment coefficient is input into the deep fuzzy adaptive controller by the calculation module, and the motor output auxiliary steering torque is calculated according to the product of the basic motor torque and the transmission ratio, thereby ensuring precise control of the steering assist; the operation module obtains the optimal transmission ratio combination under constant output torque through dynamic matching operation of the coordinated transmission ratio control unit, thereby reducing the ratio of the steering input angle to the output angle; the compensation module uses the temperature-efficiency mapping model to perform real-time compensation for the transmission efficiency, and corrects the motor output torque through the efficiency compensation coefficient, thereby ensuring the stability of the system under different working conditions; the control module performs closed-loop optimization operation on the system parameters, generates precise steering control instructions, and realizes effective control of the number of steering wheel rotations. Through multi-stage transmission ratio optimization and real-time compensation control, the entire system significantly reduces the number of steering wheel turns without affecting the steering output torque, while maintaining the smoothness and controllability of the steering operation, improving the control convenience of the commercial vehicle steering system.

[0050] In a specific embodiment, the acquisition module 101 is used to:

[0051] (1) Receiving the steering wheel target circle value set by the user through the human-computer interaction interface;

[0052] (2) Divide the steering wheel input signal into time series data blocks according to the sampling frequency;

[0053] (3) Using the multi-dimensional torque sensor in the electronic control unit to sample the current input torque T in real time, generating a steering input torque sampling sequence;

[0054] (4) The displacement sensor unit in the electronic control unit performs high-frequency sampling on the current number of steering circles R to form a raw data stream of the number of steering circles;

[0055] (5) Processing the original data stream of the number of turns by differential operation, and calculating the change rate and change acceleration of the number of turns of adjacent sampling points respectively;

[0056] (6) Data fusion is performed based on the steering wheel target circle value, steering input torque sampling sequence, steering circle raw data stream, circle change rate and circle change acceleration to construct the steering state feature vector;

[0057] (7) The Kalman filter is used to remove noise from the steering state feature vector to obtain a multi-dimensional steering input parameter set.

[0058] Specifically, the acquisition module 101 in the steering control system of a commercial vehicle with a small number of turns receives the steering wheel target turn value set by the user through the human-computer interaction interface, wherein the steering wheel steering input signal is first divided into time series data blocks according to the sampling frequency, and based on the sampling frequency of 1000Hz, a time series data block is formed every 10ms, and each data block contains the original signal data of 10 sampling points. Subsequently, the current input torque T is sampled in real time through the multi-dimensional torque sensor in the electronic control unit. The strain sensing unit in the multi-dimensional torque sensor is composed of 4 strain gauges to form a full-bridge circuit. When the steering wheel rotates, the strain gauge is deformed by force, resulting in a change in resistance value. The full-bridge circuit converts the resistance change into a voltage signal, which is amplified and filtered by the signal conditioning circuit to generate a steering input torque sampling sequence.

[0059] At the same time, the displacement sensing unit in the electronic control unit uses a Hall sensor to perform a high-frequency sampling of 1000Hz on the current number of steering turns R. The Hall sensor obtains the number of steering turns information by detecting the position change of the permanent magnet, and the output analog signal is converted into a raw data stream of the number of steering turns after A / D conversion. The raw data stream of the number of steering turns is processed by differential operation to calculate the change rate and change acceleration of the number of steering turns at adjacent sampling points. The specific calculation formula is as follows:

[0060]

[0061] in, represents the rate of change of angle at time t, represents the angle value at time t, Indicates the angle value at the previous moment, Indicates the sampling time interval.

[0062]

[0063] in, represents the angular acceleration at time t, represents the angular velocity value at time t, represents the angular velocity value at the previous moment, Indicates the sampling time interval.

[0064] Data fusion is performed based on the steering wheel target circle value, steering input torque sampling sequence, steering circle raw data stream, circle change rate and circle change acceleration to construct the steering state feature vector. The data fusion adopts the sliding time window method with a window length of 100ms. The data in the window is synchronized and time-stamped to construct a 4×100-dimensional steering state feature vector, in which the four dimensions correspond to torque T, steering circle R, circle change rate and circle change acceleration. The steering state feature vector is de-noised using a Kalman filter. The Kalman filter includes two steps: prediction and update. The prediction step predicts the state and error covariance of the current moment based on the state of the previous moment; the update step corrects the predicted value based on the observed value. The state equation of the filter adopts a fourth-order state model, and the observation equation corresponds to four measured values. After filtering, a multi-dimensional steering input parameter set is obtained.

[0065] For example, when the driver turns the steering wheel, the multi-dimensional torque sensor detects the change in the current input torque T. Assume that within a certain 100ms time window, the resistance change value output by the strain sensor unit is converted into a set of torque data through the signal conditioning circuit. At the same time, the change value of the current number of steering circles R detected by the displacement sensor unit is converted into steering circle data through A / D conversion. These steering circle data are differentially calculated to obtain the rate of change of circles and the acceleration data of the change of circles. These four sets of data are aligned on the time axis to construct the steering state feature vector. The feature vector is processed by the Kalman filter to filter out the noise introduced by the sensor itself and external interference, and obtain a multi-dimensional steering input parameter set. These parameters will be used in the subsequent steering control process.

[0066] In a specific embodiment, the adjustment module 102 is used to:

[0067] (1) Based on the angular acceleration data in the multi-dimensional steering input parameter set, the stress state of the double-row asymmetric recirculating ball structure is analyzed to generate the recirculating ball load distribution data;

[0068] (2) Calculate the contact angle change of the mechanical circulating ball based on the circulating ball load distribution data and obtain the transmission ratio change parameter;

[0069] (3) Compensating the mechanical circulating ball transmission ratio using the transmission ratio variation parameter to obtain the mechanical circulating ball transmission ratio adjustment amount;

[0070] (4) Converting the mechanical circulating ball transmission ratio adjustment amount into a first adjustment coefficient;

[0071] (5) Extract steering angle data and angular velocity data from the multi-dimensional steering input parameters and establish the transmission characteristic curve of the variable pitch worm gear mechanism;

[0072] (6) Calculate the position of the meshing contact point of the variable pitch worm gear mechanism according to the transmission characteristic curve and generate pitch change data;

[0073] (7) Using the pitch variation data to perform compensation calculation on the transmission ratio to be processed, and forming a correction amount of the transmission ratio to be processed;

[0074] (8) Dynamic adjustment processing is performed on the transmission ratio correction amount to be processed to obtain a second adjustment coefficient.

[0075] Specifically, after receiving the multi-dimensional steering input parameter set, the adjustment module 102 first analyzes the stress state of the double-row asymmetric circulating ball structure according to the angular acceleration data therein. The double-row asymmetric circulating ball structure uses two rows of circulating balls with different ball diameters and arrangement spacings to form an asymmetric layout. The load size and direction borne by each circulating ball are calculated based on the angular acceleration data to generate circulating ball load distribution data.

[0076] The formula for calculating the contact angle change of the mechanical circulating ball based on the circulating ball load distribution data is:

[0077]

[0078] in, is the actual contact angle, is the initial contact angle, is the sphere deformation coefficient, is the load distribution force, is the elastic modulus, is the raceway inclination angle.

[0079] The compensation formula of mechanical circulating ball transmission ratio is:

[0080]

[0081] The mechanical circulating ball transmission ratio adjustment amount is converted into a first adjustment coefficient.

[0082] At the same time, the steering angle data and angular velocity data are centrally extracted from the multi-dimensional steering input parameters to establish the transmission characteristic curve of the variable pitch worm gear mechanism. The worm pitch of the variable pitch worm gear mechanism is gradually distributed along the axial direction, with a smaller pitch in the middle section and a gradually increasing pitch at both ends. The position of the meshing contact point of the variable pitch worm gear mechanism is calculated according to the transmission characteristic curve. The meshing contact point is the point where the worm wheel tooth surface contacts the worm helical surface, and the position of this point directly determines the actual working pitch. The pitch change data is generated by calculating the difference between the pitch value of the current working point and the reference pitch.

[0083] The formula for compensating the transmission ratio to be processed using the pitch variation data is:

[0084]

[0085] in, is the transmission ratio after compensation, is the base transmission ratio, is the pitch variation, is the nominal pitch, is the gear compensation factor.

[0086] The conversion formula of the second adjustment coefficient is obtained by dynamically adjusting the transmission ratio correction amount to be processed:

[0087]

[0088] in, is the second adjustment coefficient, is the stiffness influence coefficient, is the load factor.

[0089] For the double-row asymmetric recirculating ball structure, its stress state is analyzed based on the angular acceleration data. The double-row asymmetric recirculating ball structure uses two rows of recirculating balls with different ball diameters and arrangement spacing to form an asymmetric layout. The angular acceleration data reflects the dynamic load changes during the steering process, and the load size and direction borne by each recirculating ball are calculated based on this to generate the recirculating ball load distribution data.

[0090] in, is the mechanical circulating ball transmission ratio adjustment, is the base transmission ratio, is the circulating ball efficiency coefficient.

[0091] For example: when the driver turns the steering wheel quickly, the angular acceleration data in the multi-dimensional steering input parameter set shows that the steering acceleration is large, causing the circulating ball to bear uneven load. The generated circulating ball load distribution data shows that the inner circulating ball row bears a large radial force, and the outer circulating ball row mainly bears axial force. This uneven load causes the contact angle between the circulating ball and the raceway to change, and the mechanical circulating ball transmission ratio needs to be compensated and converted into the first adjustment coefficient. At the same time, the steering angle data and angular velocity data extracted from the parameter set show that the steering wheel deviates from the center position and the steering speed is fast. The transmission characteristic curve established based on these data indicates that the current working point is located at both ends of the worm. The generated pitch change data shows that the current pitch is larger than the base pitch, and it is necessary to perform compensation calculations on the transmission ratio to be processed, and obtain the second adjustment coefficient through dynamic adjustment processing to complete the dynamic adjustment of the transmission ratio.

[0092] In a specific embodiment, the calculation module 103 is used to:

[0093] (1) Combining the first adjustment coefficient and the second adjustment coefficient to form transmission ratio characteristic data;

[0094] (2) Perform normalization calculation on the transmission ratio characteristic data to generate a torque calculation reference value;

[0095] (3) Calculate the basic motor torque using the torque calculation reference value to obtain the basic motor torque value;

[0096] (4) Perform data product operation on the basic motor torque value, the mechanical recirculating ball transmission ratio and the worm gear transmission ratio to obtain the initial value of the motor output auxiliary steering torque;

[0097] (5) The initial value of the motor output auxiliary steering torque is corrected by a deep fuzzy adaptive controller to obtain the motor output auxiliary steering torque;

[0098] (6) A control quantity mapping relationship is established based on the motor output auxiliary steering torque to generate a motor output control signal.

[0099] Specifically, the calculation module 103 receives the first adjustment coefficient and the second adjustment coefficient from the adjustment module 102, and combines the two coefficients into transmission ratio characteristic data. During the combination process, the two coefficients are arranged in a matrix form according to the working characteristics of the steering mechanism to form a data structure containing the complete transmission characteristics of the variable pitch worm gear mechanism and the double-row asymmetric recirculating ball structure. When the transmission ratio characteristic data is normalized, a linear mapping method is used to standardize the data range to the [0,1] interval. The standardization process takes into account the physical limitations and working range of the transmission mechanism, scales the original data proportionally according to the actual working boundaries, and converts it into a torque calculation reference value.

[0100] The basic motor torque is calculated using a polynomial fitting method, and the calculation formula is:

[0101]

[0102] in, is the basic motor torque value, is the motor reference torque, are the polynomial coefficients, is the base value for torque calculation, is the load correction factor, is the speed influence coefficient, and N is the polynomial order.

[0103] The initial value of the motor output auxiliary steering torque is calculated by multiplying the basic motor torque value with the mechanical recirculating ball transmission ratio and the worm gear transmission ratio. This process takes into account the transmission characteristics of the variable pitch worm gear mechanism and the double-row asymmetric recirculating ball structure, and the motor output torque is amplified through two-stage transmission to obtain the auxiliary steering torque. The deep fuzzy adaptive controller adopts a five-layer deep neural network structure, including an input layer, three hidden layers and an output layer. The input layer receives the initial value of the motor output auxiliary steering torque, the hidden layer performs reasoning operations through fuzzy rules, and the output layer generates the corrected motor output auxiliary steering torque. The fuzzy rules of the controller are based on multiple input variables such as steering conditions, vehicle speed, and road conditions, and dynamically adjust the weights and biases of the hidden layer neurons through an adaptive learning algorithm.

[0104] Finally, the mapping relationship between the motor output auxiliary steering torque and the motor control parameters is established. The mapping process uses a piecewise linear interpolation method to convert the torque value into specific control parameters such as the motor's voltage, current, and duty cycle to generate the motor output control signal. The control signal contains the frequency, duty cycle, phase and other parameters of the PWM waveform, which is directly used to drive the motor to operate.

[0105] For example, when a commercial vehicle performs a steering operation, the second adjustment coefficient output by the adjustment module reflects the working state of the variable pitch worm gear mechanism, and the first adjustment coefficient characterizes the transmission characteristics of the double-row asymmetric recirculating ball structure. These two coefficients are combined into transmission ratio characteristic data, and the torque calculation reference value is obtained after normalization. According to the torque calculation reference value, combined with information such as vehicle load status and steering speed, the basic motor torque value is calculated. This torque value is multiplied by the two transmission ratios to obtain a preliminary auxiliary steering torque. The deep fuzzy adaptive controller corrects this torque based on the current steering condition, converts it into a specific motor control signal, and drives the motor to output a suitable auxiliary steering torque. Data processing and calculations throughout the process are carried out in real time to ensure the timeliness and accuracy of steering control.

[0106] In a specific embodiment, the computing module 104 is used to:

[0107] (1) Extract the torque control variable and the angle control variable from the motor output control signal and construct the transmission ratio constraint function;

[0108] (2) The transmission ratio constraint function is used to define the variation range of the mechanical recirculating ball transmission ratio and the worm gear transmission ratio, and the transmission ratio adjustment range is obtained;

[0109] (3) Discretize the mechanical recirculating ball transmission ratio and the worm gear transmission ratio according to the transmission ratio adjustment range to generate a transmission ratio combination sequence;

[0110] (4) Calculate the torque transfer characteristics based on the transmission ratio combination sequence to obtain the torque distribution ratio data;

[0111] (5) Select transmission ratio data pairs that meet the constant output torque condition from the torque distribution ratio data and construct a transmission ratio optimization data set;

[0112] (6) The steering input-output angle ratio is calculated for the transmission ratio optimization data set, and the transmission ratio combination that meets the reduction requirements is selected as the optimal transmission ratio combination.

[0113] Specifically, the operation module 104 extracts two basic parameters, namely, torque control amount and angle control amount, from the motor output control signal. The torque control amount indicates the magnitude of the auxiliary steering torque output by the motor, and the angle control amount indicates the rotation angle of the steering wheel. The two parameters are used to construct a transmission ratio constraint function, which defines the reasonable variation range of the mechanical recirculating ball transmission ratio and the worm gear transmission ratio. The constraint function establishes a mapping relationship between the torque control amount, the angle control amount and the transmission ratio, and converts the steering condition into a constraint condition of the transmission ratio through mathematical modeling.

[0114] The transmission ratio constraint function is used to define the range of mechanical recirculating ball transmission ratio and worm gear transmission ratio, and the transmission ratio adjustment range is obtained. The adjustment range takes into account the physical limitations of the variable pitch worm gear mechanism and the double-row asymmetric recirculating ball structure to ensure that the change of the transmission ratio does not exceed the load-bearing capacity of the mechanism.

[0115] According to the transmission ratio adjustment range, the uniform sampling method is used for discretization. In the two-dimensional space of the mechanical recirculating ball transmission ratio and the worm gear transmission ratio, the grid is divided according to the set sampling interval, and each grid point corresponds to a set of transmission ratio combinations. These transmission ratio combinations form a transmission ratio combination sequence, and each element in the sequence contains a pair of feasible transmission ratio values.

[0116] The formula for calculating the torque transfer characteristics based on the transmission ratio combination sequence is:

[0117]

[0118] in, Assign proportional data to the moment, is the worm gear transmission efficiency, is the meshing factor, is the weight coefficient, is the current transmission ratio combination, is the average transmission ratio, is the distribution parameter, is the circulating ball load factor, and N is the number of sampling points.

[0119] From the torque distribution ratio data, the transmission ratio combinations with output torque fluctuations within the allowable range are screened. This screening process is based on the statistical characteristics of the torque distribution ratio data to construct a transmission ratio optimization data set, which contains all transmission ratio data pairs that meet the constant output torque condition.

[0120] The steering input-output angle ratio is calculated for each transmission ratio combination in the transmission ratio optimization data set. This ratio reflects the relationship between the steering wheel rotation angle and the wheel steering angle. The smaller the ratio, the more sensitive the steering. The transmission ratio combination whose ratio meets the reduction requirement is selected as the optimal transmission ratio combination.

[0121] For example, when a commercial vehicle makes a turn, the motor output control signal contains the torque control quantity and the angle control quantity that characterize the current steering demand. The transmission ratio constraint function constructed with this information determines the transmission ratio adjustment range. Discretization is performed within this range to obtain a transmission ratio combination sequence. The torque transfer characteristics are calculated based on the sequence, and the transmission ratio data pairs that meet the constant output torque conditions are screened out through the torque distribution ratio data. Finally, the steering input-output angle ratio is calculated for these transmission ratio optimization data sets, and the optimal combination is selected as the optimal transmission ratio combination, which not only meets the torque output requirements but also reduces the number of steering wheel turns.

[0122] In a specific embodiment, the compensation module 105 is used to:

[0123] (1) Extract the working parameters of the recirculating ball and worm gear from the optimal transmission ratio combination to generate the operating status data of the transmission mechanism;

[0124] (2) Collecting temperature sensor signals based on the operating status data of the transmission mechanism to obtain temperature distribution characteristics;

[0125] (3) Calculate the friction coefficient of the circulating ball and the friction coefficient of the worm gear using the characteristic quantity of temperature distribution to obtain the friction loss data of the mechanism;

[0126] (4) Calculate the mechanical circulating ball efficiency and worm gear transmission efficiency based on the friction loss data of the mechanism to obtain the efficiency characteristic parameters;

[0127] (5) Constructing the temperature-efficiency correlation function based on the efficiency characteristic parameters and generating the efficiency compensation demand;

[0128] (6) The efficiency compensation demand is converted into an efficiency compensation coefficient, which is used to correct the motor output torque.

[0129] Specifically, the compensation module 105 extracts the working parameters of the recirculating ball and the worm gear from the optimal transmission ratio combination. The working parameters of the worm gear include key data such as meshing position, meshing pressure angle, and sliding speed; the working parameters of the recirculating ball include characteristic quantities such as the force direction, contact pressure, and rolling speed of the recirculating ball. These parameter combinations generate the operating status data of the transmission mechanism, reflecting the real-time working conditions of the steering mechanism.

[0130] The temperature sensing signal is collected based on the operating status data of the transmission mechanism. The temperature sensors are arranged in key parts such as the worm gear meshing area, the recirculating ball motion track, and the bearing seat, with a sampling frequency of 10Hz. The temperature data of each sensor point is processed by the signal conditioning circuit to form a temperature data matrix containing multiple temperature measurement points. The discrete temperature measurement points are spatially reconstructed through the interpolation algorithm to obtain the temperature distribution characteristic quantity.

[0131] The temperature distribution characteristic quantity is used to calculate the friction coefficient of the worm gear and the friction coefficient of the recirculating ball. The friction coefficient calculation takes into account the influence of temperature on the viscosity of the lubricating oil, as well as the surface roughness of the mechanism, contact stress and other factors. The changes in these friction coefficients directly affect the transmission efficiency of the mechanism. By establishing a friction torque model, the friction loss data of the mechanism is obtained.

[0132] According to the friction loss data of the mechanism, the mechanical circulating ball efficiency and the worm gear transmission efficiency are calculated respectively. The geometric characteristics, load distribution, movement speed and other influencing factors of the mechanism are considered in the calculation process to obtain the efficiency characteristic parameters. The efficiency characteristic parameters include multiple quantitative indicators such as static transmission efficiency and dynamic efficiency attenuation coefficient.

[0133] The temperature-efficiency correlation function is constructed based on the efficiency characteristic parameters. The correlation function adopts a piecewise continuous mathematical model to describe the variation law of transmission efficiency in different temperature ranges. On this basis, the efficiency compensation demand is generated through numerical calculation, which reflects the deviation between the actual transmission efficiency and the ideal efficiency.

[0134] The efficiency compensation demand is converted into an efficiency compensation coefficient. This coefficient is used as a correction factor for the motor output torque to make real-time corrections to the motor output torque, thereby compensating for the transmission efficiency loss caused by temperature changes.

[0135] For example, when a commercial vehicle is in a continuous steering process, the working parameters extracted from the optimal transmission ratio combination show that the mechanism is in a high-load state. The temperature sensor signal shows that the temperature in the meshing area rises faster, while the peripheral temperature changes more slowly, forming an uneven temperature distribution characteristic. This distribution causes the friction coefficient to change, and the obtained mechanism friction loss data shows that the transmission efficiency is reduced. The temperature-efficiency correlation function constructed by the efficiency characteristic parameters calculates the efficiency compensation demand and converts it into an efficiency compensation coefficient, which is used to correct the motor output torque and maintain the stability of the steering system.

[0136] In a specific embodiment, if Figure 2 As shown, it is a schematic diagram of the structure of the control module 106 in an embodiment of the present application. The control module 106 includes:

[0137] A compensation unit 1061 is used to perform compensation processing on the steering system operating parameters according to the efficiency compensation coefficient to generate steering characteristic compensation data;

[0138] A comparison unit 1062 is used to compare and calculate the steering characteristic compensation data with the actual steering state data to obtain a steering characteristic error amount;

[0139] The correction unit 1063 is used to perform a closed-loop correction operation on the system parameters according to the steering characteristic error to obtain the system parameter optimization amount;

[0140] A calculation unit 1064 is used to calculate the steering control amount using the system parameter optimization amount to obtain basic steering control data;

[0141] A generating unit 1065, configured to calculate the number of steering wheel rotations according to the basic steering control data and generate a number of rotation control parameter;

[0142] The conversion unit 1066 is used to convert the rotation number control parameter into a steering control instruction, so as to control the steering wheel rotation number to be within a preset range.

[0143] Specifically, the control module 106 includes six functional units. The compensation unit 1061 receives the efficiency compensation coefficient and performs compensation processing on the operating parameters of the steering system. The operating parameters include key parameters such as steering torque, speed, and transmission ratio. The compensation unit 1061 performs correction calculations on these parameters according to the efficiency compensation coefficient. The compensation process adopts a parameter mapping method to establish a corresponding relationship between the compensation coefficient and each operating parameter, adjusts the original parameters by the correction coefficient, and generates steering characteristic compensation data. The comparison unit 1062 compares the steering characteristic compensation data with the actual steering state data. The actual steering state data comes from the real-time collection of each sensor, including the measured values ​​of steering angle, steering torque, speed, etc. The comparison unit 1062 uses a data comparison algorithm to calculate the difference between the compensation data and the measured data to obtain a specific steering characteristic error. This error reflects the deviation between the theoretical state after compensation and the actual operating state.

[0144] The correction unit 1063 performs a closed-loop correction operation according to the steering characteristic error. The closed-loop correction adopts the proportional-integral-differential (PID) control algorithm to decompose the error into a proportional term, an integral term, and a differential term. The proportional term directly corresponds to the current error, the integral term eliminates the cumulative error, and the differential term predicts the error change trend. By weighted combination of the three terms, the optimal adjustment amount of the system parameters is calculated to obtain the system parameter optimization amount. The calculation unit 1064 uses the system parameter optimization amount to calculate the steering control amount. The control amount calculation process takes into account multiple influencing factors such as vehicle speed, road conditions, and load, and adopts a multivariable control algorithm to convert the optimization amount into specific control parameters. These control parameters include electrical parameters such as motor current, voltage, and duty cycle, as well as related parameters of the mechanical transmission system, forming basic steering control data.

[0145] The generation unit 1065 receives the basic steering control data and calculates the number of steering wheel rotations. The number of rotations is calculated based on the steering angle and the transmission ratio, while taking into account the steering limit and mechanical constraints. The generation unit 1065 compares the calculation result with the preset number of rotations range, and generates a control parameter for limiting the number of steering wheel rotations, i.e., the number of rotations control parameter, by adjusting the control parameter. The conversion unit 1066 converts the number of rotations control parameter into a specific steering control instruction. The conversion process uses a table lookup interpolation method to establish a corresponding relationship between the control parameter and the execution instruction. The steering control instruction contains specific execution indicators such as the PWM signal parameters of the drive motor and the control amount of the mechanical transmission system.

[0146] For example: when a commercial vehicle makes a large angle turn, the transmission efficiency decreases due to the increase in the temperature of the steering mechanism. The compensation unit 1061 performs compensation calculations on parameters such as the steering torque based on the received efficiency compensation coefficient. The comparison unit 1062 collects the actual steering state through the sensor and finds that there is a deviation between the compensated steering torque and the actual torque. The correction unit 1063 performs PID calculation based on this deviation to obtain the optimized adjustment amount. The calculation unit 1064 converts the optimization amount into specific motor control parameters. The generation unit 1065 calculates the number of steering wheel turns based on these parameters, and finds that the number of turns exceeds the preset range, so it generates corresponding limit parameters. The conversion unit 1066 converts these parameters into specific control instructions such as PWM waveforms, which directly act on the actuator to achieve precise control of the number of steering turns.

[0147] In a specific embodiment, the calculation unit 1064 is specifically configured to:

[0148] (1) Extract the torque optimization parameters and angle optimization parameters from the system parameter optimization quantity to generate dual-channel control quantity;

[0149] (2) Calculate the torque response coefficient based on the dual-channel control quantity to obtain the torque compensation quantity;

[0150] (3) Perform nonlinear processing on the torque compensation to obtain the damping correction coefficient;

[0151] (4) Using the damping correction coefficient to adjust and calculate the steering feedback force to form a steering control reference value;

[0152] (5) Determine the steering assist characteristic curve based on the steering control reference value and obtain the assist compensation amount;

[0153] (6) The power assist compensation amount and the steering control reference value are synthesized to generate basic steering control data.

[0154] Specifically, the calculation unit 1064 performs the calculation process of the steering control amount, and separates the torque optimization parameter and the angle optimization parameter from the system parameter optimization amount. The torque optimization parameter reflects the direction and amplitude of the steering torque to be adjusted, and the angle optimization parameter represents the correction amount of the steering angle. These two parameters are extracted through the data separation algorithm to form a dual-channel control amount including a torque channel and an angle channel.

[0155] The formula for calculating the torque response coefficient of the dual-channel control quantity is:

[0156]

[0157] in, is the torque compensation, Enter the value for the torque channel, Enter a value for the Angle channel, is the road surface characteristic coefficient, is the current vehicle speed, is the base speed, is the speed influencing factor, and N is the number of sampling points.

[0158] The torque compensation amount is processed nonlinearly to obtain the damping correction coefficient. The nonlinear processing adopts the piecewise function method, and different processing strategies are adopted under different working conditions. For small-angle steering, a linear mapping relationship is adopted; for large-angle steering, a nonlinear function is used to adapt to the changing characteristics of the steering load. The damping correction coefficient is used to adjust the steering feedback force. The steering feedback force is the resistance felt by the driver through the steering wheel, which needs to be dynamically adjusted according to factors such as vehicle speed and steering angle. The adjustment process adopts a damping mapping algorithm to convert the damping correction coefficient into a specific feedback force adjustment amount to form a steering control reference value.

[0159] The steering control reference value determines the shape of the steering power characteristic curve. The characteristic curve describes the relationship between the steering power torque and the steering input, and generates a continuous power characteristic function through a curve fitting algorithm. According to this function, the power compensation required under specific working conditions is calculated. When the power compensation amount and the steering control reference value are combined for data, a weighted fusion algorithm is used. Under different vehicle speeds and steering angles, the weight coefficients of the two parameters will be dynamically adjusted to ensure that appropriate control data can be obtained under various working conditions. The generated basic steering control data contains a complete set of steering control parameters.

[0160] For example, when the driver of a commercial vehicle quickly turns the steering wheel to make a turn, the calculation unit 1064 extracts the data of the torque channel and the angle channel from the system parameter optimization amount. The torque channel data reflects the change of the steering load, and the angle channel data represents the rate of change of the steering wheel angle. The data of these two channels are calculated by the response coefficient to obtain the torque compensation amount that takes into account the influence of road conditions and vehicle speed. The compensation amount is converted into a damping correction coefficient through nonlinear processing, which is used to adjust the magnitude of the steering feedback force. After the feedback force is adjusted, a steering control reference value is formed, and then the steering power assist characteristic curve is determined. The power assist compensation amount calculated according to the characteristic curve is synthesized with the reference value to generate basic steering control data containing motor control parameters. During the entire calculation process, a strict logical relationship is maintained between various parameters to ensure the continuity and stability of the steering control.

[0161] In a specific embodiment, the generating unit 1065 is specifically configured to:

[0162] (1) Extracting the rotation angle data and speed data from the basic steering control data to form steering wheel motion feature data;

[0163] (2) Using the steering wheel motion characteristic data, calculate the angle increment during a single steering process and obtain the change in the number of turns;

[0164] (3) Accumulate the change in the number of turns to obtain the actual number of turns of the steering wheel;

[0165] (4) Compare the actual number of steering wheel rotations with the steering limit data to generate a number deviation value;

[0166] (5) Compensate the steering torque distribution according to the number of turns deviation value to obtain the number of turns correction value;

[0167] (6) The angle constraint condition is constructed through the number of turns correction value, and the number of turns control parameter is generated.

[0168] Specifically, the generation unit 1065 extracts two key parameters from the basic steering control data: rotation angle data and rotation speed data. The rotation angle data is collected by the steering wheel angle sensor, indicating the deflection angle of the steering wheel relative to the neutral position; the rotation speed data is measured by the angular velocity sensor, reflecting the rotation rate of the steering wheel. After data filtering and synchronization processing, these two data form a feature data set describing the motion state of the steering wheel.

[0169] The following formula is used to calculate the angle increment during a single turn:

[0170]

[0171] in, is the change in number of turns, is the instantaneous value of the angle, is the instantaneous value of the speed, is the maximum permissible speed, To turn to the center moment, is the characteristic period, the integration interval [ , ] is the start and end time of a single turning process.

[0172] When accumulating the number of turns, the time window method is used to perform segmented statistics on the continuous steering process. The number of turns in each time window is weighted and accumulated to obtain the actual number of turns of the steering wheel. The accumulation process takes into account the change in steering direction, and the forward and reverse turns are counted separately. The steering limit data is the pre-set maximum allowable number of turns of the steering wheel, which is determined based on the physical constraints and operational safety requirements of the commercial vehicle steering mechanism. The actual number of turns of the steering wheel is compared with the steering limit data in real time to calculate the number of turns deviation value. The deviation value represents the difference between the current number of turns and the limit value.

[0173] The number of turns deviation value is used to compensate for the steering torque distribution. The compensation calculation adopts a nonlinear mapping method. When the number of turns approaches the limit value, the steering resistance is increased to limit further rotation. This process generates a number of turns correction value, which is used to adjust the steering assist characteristics. The number of turns correction value is used to construct angle constraints. The constraints are in the form of piecewise functions, and different constraint strategies are used in different number of turns intervals. These constraints are converted into specific control parameters, including torque limit values, angular velocity limit values, etc., to form a complete number of turns control parameter set.

[0174] For example, when the driver of a commercial vehicle performs a U-turn on the spot, the generation unit 1065 receives the angle and speed signals of the steering wheel. Assuming that the driver starts to turn the steering wheel quickly, the angle sensor detects the continuous angle change, and the angular velocity sensor records the rotation rate at the same time. These data are processed to form the steering wheel motion characteristic data. Based on these characteristic data, the angle increment during a single steering process is calculated. As the steering process continues, the system accumulates the angle increment and tracks the number of turns the steering wheel has made. When the number of turns approaches the preset limit value, the system calculates the number of turns deviation value and generates a torque compensation amount based on it. The compensation amount is converted into a specific constraint condition to limit the continued rotation of the steering wheel. The entire process achieves precise control of the number of turns of the steering wheel through continuous data collection, processing and real-time adjustment of control parameters.

[0175] The above describes the steering control system for a commercial vehicle with a small number of circles in the embodiment of the present application. The following describes the steering control method for a commercial vehicle with a small number of circles in the embodiment of the present application. Figure 3 In the embodiment of the present application, an embodiment of the steering control method for a commercial vehicle with a small number of turns includes:

[0176] S201, according to the target number of steering wheel turns set by the user, the electronic control unit collects and processes the current input torque T and the number of steering turns R to obtain a multi-dimensional steering input parameter set;

[0177] S202, based on the multi-dimensional steering input parameter set, adaptively adjust the mechanical recirculating ball transmission ratio to obtain a first adjustment coefficient, and dynamically adjust the worm gear transmission ratio to obtain a second adjustment coefficient;

[0178] S203, using the first adjustment coefficient and the second adjustment coefficient, calculating the auxiliary steering torque output by the motor in real time to obtain a motor output control signal;

[0179] S204, performing dynamic matching operation on the mechanical circulating ball transmission ratio and the worm gear transmission ratio according to the motor output control signal to obtain an optimal transmission ratio combination;

[0180] S205, performing real-time compensation calculation on the worm gear transmission efficiency and the mechanical circulating ball efficiency according to the optimal transmission ratio combination to obtain an efficiency compensation coefficient;

[0181] S206: Based on the efficiency compensation coefficient, a closed-loop optimization operation is performed on the system parameters to obtain a steering control instruction, and the number of steering wheel rotations is controlled within a preset range through the steering control instruction.

[0182] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A steering control system for a small number of turns of a commercial vehicle, characterized in that: The small-turn commercial vehicle steering control system comprises: The acquisition module is used to acquire and process the current input torque T and the number of steering turns R through the electronic control unit according to the target number of steering wheel turns set by the user, and obtain a multi-dimensional steering input parameter set; an adjustment module, the adjustment module being electrically connected to the acquisition module and configured to adaptively adjust the mechanical recirculating ball transmission ratio based on the multi-dimensional steering input parameter set to obtain a first adjustment coefficient, and dynamically adjust the worm gear transmission ratio to obtain a second adjustment coefficient; a calculation module, the calculation module being electrically connected to the adjustment module and configured to calculate the auxiliary steering torque output by the motor in real time by using the first adjustment coefficient and the second adjustment coefficient to obtain a motor output control signal; An operation module, the operation module is electrically connected to the calculation module, and is used to perform a dynamic matching operation on the mechanical circulating ball transmission ratio and the worm gear transmission ratio according to the motor output control signal to obtain an optimal transmission ratio combination; A compensation module, which is electrically connected to the calculation module and is used to perform real-time compensation calculation on the worm gear transmission efficiency and the mechanical circulating ball efficiency according to the optimal transmission ratio combination to obtain an efficiency compensation coefficient; A control module is electrically connected to the compensation module and is used to perform closed-loop optimization calculations on system parameters based on the efficiency compensation coefficient to obtain a steering control instruction, and control the number of steering wheel rotations within a preset range through the steering control instruction.

2. The small-turn commercial vehicle steering control system according to claim 1, characterized in that: The acquisition module is used for: Receive the steering wheel target circle value set by the user through the human-computer interaction interface; Divide the steering wheel input signal into time series data blocks according to the sampling frequency; The multi-dimensional torque sensor in the electronic control unit is used to sample the current input torque T in real time to generate a steering input torque sampling sequence; The displacement sensor unit in the electronic control unit performs high-frequency sampling on the current number of steering circles R to form a raw data stream of the number of steering circles; The original data stream of the number of steering turns is processed by differential operation, and the change rate and change acceleration of the number of steering turns of adjacent sampling points are calculated respectively; Performing data fusion according to the steering wheel target circle value, the steering input torque sampling sequence, the steering circle raw data stream, the circle change rate and the circle change acceleration to construct a steering state feature vector; A Kalman filter is used to remove noise from the steering state feature vector to obtain the multi-dimensional steering input parameter set.

3. The small-turn commercial vehicle steering control system according to claim 1, characterized in that: The regulating module is used for: Analyzing the stress state of the double-row asymmetric recirculating ball structure according to the angular acceleration data in the multi-dimensional steering input parameter set to generate recirculating ball load distribution data; Calculate the contact angle change of the mechanical circulating ball according to the circulating ball load distribution data to obtain the transmission ratio change parameter; The transmission ratio variation parameter is used to compensate the mechanical circulating ball transmission ratio to obtain a mechanical circulating ball transmission ratio adjustment amount; Converting the mechanical circulating ball transmission ratio adjustment amount into the first adjustment coefficient; Extracting steering angle data and angular velocity data from the multi-dimensional steering input parameters to establish a transmission characteristic curve of a variable pitch worm gear mechanism; Calculating the position of the meshing contact point of the variable pitch worm gear mechanism according to the transmission characteristic curve to generate pitch variation data; Using the pitch variation data to perform compensation calculation on the transmission ratio to be processed, to form a correction amount of the transmission ratio to be processed; The second adjustment coefficient is obtained by performing dynamic adjustment processing through the transmission ratio correction amount to be processed.

4. The small-turn commercial vehicle steering control system according to claim 1, characterized in that: The computing module is used for: combining the first adjustment coefficient and the second adjustment coefficient to form transmission ratio characteristic data; Performing normalization calculation processing on the transmission ratio characteristic data to generate a torque calculation reference value; Calculating the basic motor torque using the torque calculation reference value to obtain a basic motor torque value; Performing a data product operation on the basic motor torque value, the mechanical circulating ball transmission ratio and the worm gear transmission ratio to obtain an initial value of the motor output auxiliary steering torque; The motor output auxiliary steering torque is corrected by a deep fuzzy adaptive controller to obtain the motor output auxiliary steering torque; A control quantity mapping relationship is established according to the auxiliary steering torque output by the motor to generate the motor output control signal.

5. The small-turn commercial vehicle steering control system according to claim 1, characterized in that: The computing module is used for: Extracting torque control quantity and rotation angle control quantity from the motor output control signal to construct a transmission ratio constraint function; The transmission ratio constraint function is used to define the variation range of the mechanical circulating ball transmission ratio and the worm gear transmission ratio to obtain a transmission ratio adjustment interval; Discretize the mechanical recirculating ball transmission ratio and the worm gear transmission ratio according to the transmission ratio adjustment interval to generate a transmission ratio combination sequence; Calculating the torque transfer characteristic according to the transmission ratio combination sequence to obtain torque distribution ratio data; Selecting transmission ratio data pairs that meet the constant output torque condition from the torque distribution ratio data to construct a transmission ratio optimization data set; The steering input-output angle ratio is calculated for the transmission ratio optimization data set, and a transmission ratio combination whose ratio meets the reduction requirement is selected as the optimal transmission ratio combination.

6. The small-turn commercial vehicle steering control system according to claim 1, characterized in that: The compensation module is used for: Extracting the operating parameters of the recirculating ball and the worm gear from the optimal transmission ratio combination to generate transmission mechanism operating status data; Based on the operating state data of the transmission mechanism, the temperature sensor signal is collected to obtain a temperature distribution characteristic quantity; Calculating the friction coefficient of the circulating ball and the friction coefficient of the worm gear using the temperature distribution characteristic quantity to obtain the friction loss data of the mechanism; Calculating the mechanical circulation ball efficiency and the worm gear transmission efficiency according to the mechanism friction loss data to obtain efficiency characteristic parameters; Constructing a temperature-efficiency correlation function according to the efficiency characteristic parameters to generate an efficiency compensation demand; The efficiency compensation demand is converted into the efficiency compensation coefficient for correcting the motor output torque.

7. The small-turn commercial vehicle steering control system according to claim 1, characterized in that: The control module comprises: A compensation unit, used for compensating the steering system operating parameters according to the efficiency compensation coefficient to generate steering characteristic compensation data; A comparison unit, used for comparing and calculating the steering characteristic compensation data with the actual steering state data to obtain a steering characteristic error amount; A correction unit, used for performing a closed-loop correction operation on the system parameters according to the steering characteristic error amount to obtain an optimized amount of the system parameters; A calculation unit, used to calculate the steering control amount using the system parameter optimization amount to obtain basic steering control data; A generating unit, configured to calculate the number of steering wheel rotations according to the basic steering control data and generate a number of rotation control parameter; The conversion unit is used to convert the rotation number control parameter into the steering control instruction, so as to control the steering wheel rotation number within a preset range.

8. The small-turn commercial vehicle steering control system according to claim 7, characterized in that: The computing unit is specifically used for: Extracting torque optimization parameters and angle optimization parameters from the system parameter optimization quantity to generate dual-channel control quantity; Calculating the torque response coefficient according to the dual-channel control quantity to obtain the torque compensation quantity; Performing nonlinear processing on the torque compensation amount to obtain a damping correction coefficient; Using the damping correction coefficient to adjust and calculate the steering feedback force to form a steering control reference value; Determine a steering assist characteristic curve according to the steering control reference value to obtain an assist compensation amount; The assist compensation amount and the steering control reference value are combined to generate the basic steering control data.

9. The small-turn commercial vehicle steering control system according to claim 7, characterized in that: The generating unit is specifically used for: Extracting rotation angle data and rotation speed data from the basic steering control data to form steering wheel motion characteristic data; Calculating the angle increment during a single steering process using the steering wheel motion characteristic data to obtain a change in the number of turns; Performing cumulative calculation on the change in the number of rotations to obtain the actual number of rotations of the steering wheel; Comparing the actual number of rotations of the steering wheel with the steering limit data to generate a number of rotations deviation value; Compensation calculation is performed on the steering torque distribution according to the number of turns deviation value to obtain a number of turns correction value; The angle constraint condition is constructed by the number of turns correction amount to generate the number of turns control parameter.

10. A steering control method for a commercial vehicle with a small number of turns, characterized in that: The steering control method for a commercial vehicle with a small number of turns comprises: According to the target number of steering wheel turns set by the user, the electronic control unit collects and processes the current input torque T and the number of steering turns R to obtain a multi-dimensional steering input parameter set; Based on the multi-dimensional steering input parameter set, the mechanical recirculating ball transmission ratio is adaptively adjusted to obtain a first adjustment coefficient, and the worm gear transmission ratio is dynamically adjusted to obtain a second adjustment coefficient; Using the first adjustment coefficient and the second adjustment coefficient, the auxiliary steering torque output by the motor is calculated in real time to obtain a motor output control signal; According to the motor output control signal, a dynamic matching operation is performed on the mechanical circulating ball transmission ratio and the worm gear transmission ratio to obtain an optimal transmission ratio combination; According to the optimal transmission ratio combination, real-time compensation calculation is performed on the worm gear transmission efficiency and the mechanical circulating ball efficiency to obtain an efficiency compensation coefficient; Based on the efficiency compensation coefficient, a closed-loop optimization operation is performed on the system parameters to obtain a steering control instruction, and the number of steering wheel rotations is controlled within a preset range through the steering control instruction.

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