CN117485325B - Multi-axis distributed electric drive vehicle steering control method and vehicle - Google Patents
Multi-axis distributed electric drive vehicle steering control method and vehicle Download PDFInfo
- Publication number
- CN117485325B CN117485325B CN202410001706.3A CN202410001706A CN117485325B CN 117485325 B CN117485325 B CN 117485325B CN 202410001706 A CN202410001706 A CN 202410001706A CN 117485325 B CN117485325 B CN 117485325B
- Authority
- CN
- China
- Prior art keywords
- vehicle
- steering
- bridge
- target
- speed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 46
- 238000012546 transfer Methods 0.000 claims abstract description 11
- 230000001133 acceleration Effects 0.000 claims abstract description 5
- 230000006870 function Effects 0.000 claims description 16
- 230000009466 transformation Effects 0.000 claims description 8
- 230000007246 mechanism Effects 0.000 claims description 4
- 238000004590 computer program Methods 0.000 claims description 2
- 238000011217 control strategy Methods 0.000 abstract description 3
- 238000005516 engineering process Methods 0.000 description 7
- 238000013461 design Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 238000013473 artificial intelligence Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
- B60W30/02—Control of vehicle driving stability
- B60W30/045—Improving turning performance
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units, or advanced driver assistance systems for ensuring comfort, stability and safety or drive control systems for propelling or retarding the vehicle
- B60W30/02—Control of vehicle driving stability
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D7/00—Steering linkage; Stub axles or their mountings
- B62D7/06—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
- B62D7/14—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
- B62D7/142—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering specially adapted for particular vehicles, e.g. tractors, carts, earth-moving vehicles, trucks
- B62D7/144—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering specially adapted for particular vehicles, e.g. tractors, carts, earth-moving vehicles, trucks for vehicles with more than two axles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2520/00—Input parameters relating to overall vehicle dynamics
- B60W2520/10—Longitudinal speed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2520/00—Input parameters relating to overall vehicle dynamics
- B60W2520/10—Longitudinal speed
- B60W2520/105—Longitudinal acceleration
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2540/00—Input parameters relating to occupants
- B60W2540/10—Accelerator pedal position
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2540/00—Input parameters relating to occupants
- B60W2540/12—Brake pedal position
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2540/00—Input parameters relating to occupants
- B60W2540/18—Steering angle
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2710/00—Output or target parameters relating to a particular sub-units
- B60W2710/20—Steering systems
Abstract
The invention provides a multi-axis distributed electric drive vehicle steering control method and a vehicle, and relates to the technical field of multi-axis distributed electric drive vehicles, wherein the method comprises the following steps: during running of the vehicle, a driver outputs target acceleration to the vehicle by controlling an accelerator pedal and a brake pedal; the whole vehicle controller calculates and outputs a target vehicle speed; the driver sends a turning angle signal to the vehicle by operating the steering wheel, and outputs each bridge target turning angle signal through the geometric relationship of the bridge; the whole vehicle controller inputs the target speed of the vehicle and the target turning angle signals of each bridge into the monorail model transfer function, outputs the target yaw rate of the whole vehicle, and controls the running of the vehicle through the steering rod system of each steering bridge based on the target yaw rate, so that the reverse steering of the rear bridge and the front bridge at low speed is realized, the low-speed turning radius is reduced, and the same-direction steering of the rear bridge and the front bridge is realized at medium and high speeds. The invention relates to a control strategy for reducing the turning radius of a low-speed steering wheel by reverse steering of a rear axle and a front axle at low speed and improving the stability of a vehicle by same-direction steering of the rear axle and the front axle at medium-high speed.
Description
Technical Field
The invention relates to the technical field of multi-axis distributed electric drive vehicles, in particular to a multi-axis distributed electric drive vehicle steering control method and a vehicle.
Background
The multi-axis distributed electric drive vehicle has the characteristics of high control flexibility, short transmission chain, compact structure, high transmission efficiency, high space arrangement utilization rate and the like, and the unique structural characteristics and the driving mode lead the multi-axis distributed electric drive vehicle to bring obvious technical innovation in the aspects of fully excavating vehicle dynamics control potential, enhancing vehicle safety, improving driving efficiency, simplifying chassis structure and the like, and provide a hardware carrier for a high-performance vehicle control technology. The wheels are independently driven, and the axles are independently steered to form a distributed all-electric drive chassis, and one of the outstanding characteristics is that the moment vector of each wheel can be independently controlled, including the magnitude and the direction. By outputting accurate wheel torque and independent wheel angles, the control flexibility of chassis movement can be greatly improved, and the synergy between the two enables optimization of planar maneuver performance of the vehicle (including longitudinal, lateral and yaw movements). In terms of control strategy, multi-objective optimization for economy, dynamics, steering stability and high fault tolerance can be achieved.
The conventional vehicle steering control is performed by a steering system disposed at the front wheels, and the center rear axle follow-up does not provide steering angle support, and the turning radius is also large at low vehicle speeds. If the traditional front axle steering control method is used, the advantages of multi-axle electric drive cannot be exerted, the turning radius is large at low speed, and the vehicle stability cannot be improved at medium and high speeds.
In the prior art, application number CN110606078B discloses a multi-axis distributed electric drive vehicle steering control method, the document calculates a longitudinal reference distance of a mechanical-differential steering bridge in the current state through a fuzzy controller according to a driver input steering angle, a reference centroid side deflection angle and an actual centroid side deflection angle, then analyzes the longitudinal reference distance and the driver input steering angle according to a vehicle steering bridge geometric relationship to obtain a reference steering angle of the differential steering bridge, and then a lower steering angle tracking controller tracks the reference steering angle based on a fuzzy PID algorithm, calculates a proper differential torque to drive the differential steering bridge to finish steering. The document is not developed for a multi-axis electric drive chassis having all-wheel steering control, steering is performed by differential torque, and the advantage of a steering system of the all-wheel electric drive chassis itself is not exerted. The document does not analyze the effect of the x-distance between the steering geometry center and the centroid on the steering radius, and does not design a control function that varies with vehicle speed. The document does not realize that the reverse rotation of the low-speed rear shaft and the front shaft reduces the turning radius, and the same-direction rotation of the medium-high-speed rear shaft and the front shaft improves the stability. In the document, the front axle adopts mechanical steering, the rear axle adopts differential steering, the steering modes and structures of the front axle and the rear axle are different, and the modularized design is not realized.
Disclosure of Invention
The invention provides a multi-axis distributed electric drive vehicle steering control method, which is based on a developed monorail model transfer function, and can realize reverse steering of a rear axle and a front axle when the vehicle speed is lower than a certain reference vehicle speed, so as to help the vehicle to steer; when the vehicle speed is higher than a certain reference vehicle speed Vc, the rear four axles and the front two axles turn in the same direction, so that the stability is enhanced.
The method comprises the following steps:
during running of the vehicle, a driver outputs target acceleration to the vehicle by controlling an accelerator pedal and a brake pedal;
the whole vehicle controller calculates and outputs a target vehicle speed;
the driver sends a turning angle signal to the vehicle by operating the steering wheel, and outputs each bridge target turning angle signal through the geometric relationship of the bridge;
the whole vehicle controller inputs the target speed of the vehicle and the target turning angle signals of each bridge into the monorail model transfer function, outputs the target yaw rate of the whole vehicle, and controls the running of the vehicle through the steering rod system of each steering bridge based on the target yaw rate, so that the reverse steering of the rear bridge and the front bridge at low speed is realized, the low-speed turning radius is reduced, and the same-direction steering of the rear bridge and the front bridge is realized at medium and high speeds.
It should be further noted that, in the method, a control relationship of a multi-axle vehicle single-rail model is also established, and a single-rail model transfer function is established by adopting a method similar to a four-wheel vehicle linear two-degree-of-freedom model, such as a formula (1):
……………（1）
wherein,is the centroid slip angle of the vehicle; />Yaw rate, which is the centroid of the vehicle;
for the cornering stiffness of the nth bridge wheel, n is an integer of 1, 2, 3,/for the fifth bridge wheel>Is one of n cornering stiffness;
is the steering angle of the nth axle wheel, n is an integer of 1, 2 and 3, < ->One of the n wheel steering angles; similarly, the upper limit value of n may be set according to the total number of wheels of the vehicle.
For the position of the ith bridge, this value is positive when the bridge is in front of the centroid, otherwise negative; />The quality of the whole vehicle; />The moment of inertia is the yaw direction of the whole vehicle; />Is the vehicle x-direction speed.
It is further noted that, in the method,
and (3) carrying out Laplace transformation on the formula (1) to obtain a formula (2):
…………（2）；
is the centroid slip angle after Lagrangian transformation.
In the method, for the lateral movement of the vehicle, a zero-change centroid slip angle control is adopted, the moment of defining the target centroid slip angle is kept to be zero, and the reference value of the yaw movement control is obtained based on a formula (3):
…………………………（3）。
in the method, the geometric relationship of the multi-axle vehicle full-axle steering meeting the Ackerman steering is defined:
…………………………………………………（4）
wherein D is fp The steering center distance is the x-direction distance between the steering geometric center and the mass center, and the defined difference ratio is:
…………………………………………………（5）；
substituting the geometric relationship into the yaw dynamics model after the pull transformation to obtain:
………………………（6）；
the operation procedure sequence a is expressed as:
………（7）；
is a custom coefficient.
In the method, when the vehicle speed is lower than a preset reference vehicle speed Vc, the rear four axles and the front two axles are reversely turned to assist the vehicle to turn;
when the vehicle speed is higher than a preset reference vehicle speed Vc, defining a coefficient as shown in formula (8) to lead the rear four-axle and the front two-axle to steer in the same direction, setting a steering limit value of the rear four-axle in a reverse steering mode and a same-direction steering mode, wherein the limit value is represented by k a And k b A representation;
………………………………………（8）
the whole vehicle controller calculates the yaw angular speed of the mass center of each bridge according to the formulas (1) to (8), and outputs control signals of the electric wheel steering executing mechanism by combining the target vehicle speed and the target turning angle of each bridge.
The invention also provides a vehicle, which comprises a memory, a whole vehicle controller, an accelerator pedal, a brake pedal, a steering wheel and a computer program which is stored in the memory and can run on the whole vehicle controller, wherein the whole vehicle controller realizes the steps of the multi-axis distributed electric drive vehicle steering control method when executing the program.
From the above technical scheme, the invention has the following advantages:
the multi-axis distributed electric drive vehicle steering control method and the vehicle provided by the invention define a multi-axis vehicle single-rail model facing to top-layer control, and a control strategy for reducing the low-speed turning radius by reversely steering a rear axle and a front axle when the vehicle is in low speed and improving the stability of the vehicle by steering the rear axle and the front axle in the same direction when the vehicle is in medium-high speed is based on a modularized electric steering executing mechanism. The following functions can be realized by the multi-axis distributed electric drive vehicle steering control method:
(1) The method comprises the steps that a target vehicle speed is obtained by utilizing signals of an accelerator pedal and a brake pedal of a driver and referring to the current vehicle speed, and the target vehicle speed is used for generating a total longitudinal driving force target of the vehicle at the next moment by a top tracking controller, or the total longitudinal driving force target of the vehicle is directly generated by utilizing a pedal MAP;
(2) Giving out target steering angles of all the bridges according to different steering modes by using steering wheel angle signals and current vehicle speed signals for active steering control of all the bridges;
(3) And giving a target yaw rate by using the steering wheel angle signal and the current vehicle speed signal, and generating a vehicle total yaw moment control target by using the top tracking controller.
Drawings
In order to more clearly illustrate the technical solutions of the present invention, the drawings that are needed in the description will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method of controlling steering of a multi-axis distributed electric drive vehicle;
FIG. 2 is a block diagram of monorail model control logic;
FIG. 3 is a schematic illustration of a six-axis monorail model;
FIG. 4 is a schematic illustration of a control vehicle of the present invention;
fig. 5 is a schematic diagram of a control 6-axis vehicle.
Detailed Description
The multi-axis distributed electric drive vehicle steering control method provided by the invention combines the problems of longer vehicle body, larger dead weight, overlarge turning radius and poor trafficability at low speed of the multi-axis electric drive vehicle, and rollover accidents of medium-high speed steering. At present, in order to reduce the turning radius and improve the vehicle stability, a monorail model function is established on the basis of input signals such as an accelerator pedal position signal, a brake pedal position signal, a steering wheel angle signal, a vehicle speed signal and the like of a driver, and the target angle of rotation of each shaft, the target vehicle speed and the target yaw rate are output. Therefore, the invention can solve the problems that the front axle adopts mechanical steering and the rear axle adopts differential steering, the steering modes and structures of the front axle and the rear axle are different, and the modularized design is not realized. Based on the problem, the invention combines the whole vehicle controller, the steering wheel, the accelerator pedal and the brake pedal on the vehicle to realize reverse steering of the rear axle and the front axle when the vehicle speed is lower than a certain reference vehicle speed, thereby helping the steering of the vehicle.
The multi-axis distributed electric drive vehicle steering control method can be applied to one or more vehicles, and can also acquire and process associated data based on artificial intelligence technology. The control method has the technology of a hardware level and the technology of a software level. The method can be combined with technologies such as a sensor of a vehicle, an artificial intelligent chip for the vehicle, distributed storage, big data processing technology, an operation/interaction system and the like. In connection with programming languages, specifically include, but are not limited to, object-oriented programming languages such as Java, smalltalk, C ++, and conventional procedural programming languages such as the "C" language or similar programming languages. The target speed is obtained by establishing a linear two-degree-of-freedom model of the four-wheel vehicle and a transfer function of the monorail model and by utilizing technologies such as sensor monitoring, data transmission and the like, and is used for generating a total longitudinal driving force target of the vehicle at the next moment by a top tracking controller or directly generating the total longitudinal driving force target of the vehicle by utilizing a pedal MAP. And giving a target yaw rate by using the steering wheel angle signal and the current vehicle speed signal, and generating a vehicle total yaw moment control target by using the top tracking controller. The problems that the traditional front axle steering control method cannot exert the advantages of multi-axle electric drive, the turning radius is large at low speed, and the stability of the vehicle cannot be improved at medium and high speeds are further effectively solved.
Of course the network on which the vehicle may be located may also include, but is not limited to, the internet, a wide area network, a metropolitan area network, a local area network, a virtual private network (VirtualPrivateNetwork, VPN), and the like.
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, a flow chart of a method for controlling steering of a multi-axis distributed electric drive vehicle according to an embodiment is shown, the method includes:
s1: during running of the vehicle, a driver outputs target acceleration to the vehicle by controlling an accelerator pedal and a brake pedal;
s2: the whole vehicle controller calculates and outputs a target vehicle speed;
s3: the driver sends a turning angle signal to the vehicle by operating the steering wheel, and outputs each bridge target turning angle signal through the geometric relationship of the bridge;
s4: the whole vehicle controller inputs the target speed of the vehicle and the target turning angle signals of each bridge into the monorail model transfer function, outputs the target yaw rate of the whole vehicle, and controls the running of the vehicle through the steering rod system of each steering bridge based on the target yaw rate, so that the reverse steering of the rear bridge and the front bridge at low speed is realized, the low-speed turning radius is reduced, and the same-direction steering of the rear bridge and the front bridge is realized at medium and high speeds.
Therefore, the invention can realize reverse steering of the rear axle and the front axle when the vehicle speed is lower than a certain reference vehicle speed based on the developed transfer function of the monorail model, and help the vehicle to steer; when the vehicle speed is higher than a certain reference vehicle speed, the rear four axles and the front two axles turn in the same direction, so that the stability is enhanced.
In one embodiment of the present invention, as shown in fig. 2 to 5, a steering control method of a multi-axis distributed electric drive vehicle is combined, wherein fig. 4 shows a coordinate system of a wheel system and a coordinate system of a vehicle body, and a possible embodiment thereof will be described below without limitation in combination with the coordinate system and the related position and angle relation.
In the method, firstly, a control relation of a multi-axle vehicle monorail model is established, and a monorail model transfer function is established by adopting a method similar to a four-wheel vehicle linear two-degree-of-freedom model, such as a formula (1):
……………（1）
wherein,is the centroid slip angle of the vehicle; />Yaw rate, which is the centroid of the vehicle;
for the cornering stiffness of the nth bridge wheel, n is an integer of 1, 2, 3,/for the fifth bridge wheel>Is one of n cornering stiffness;
is the steering angle of the nth axle wheel, n is an integer of 1, 2 and 3, < ->One of the n wheel steering angles; similarly, the upper limit value of n may be set according to the total number of wheels of the vehicle. As shown in fig. 5, if the vehicle has 12 wheels, the upper limit value of n is 12.
For the position of the ith bridge, this value is positive when the bridge is in front of the centroid, otherwiseNegative; />The quality of the whole vehicle; />The moment of inertia is the yaw direction of the whole vehicle; />Is the vehicle x-direction speed.
The Laplace transform is performed on the above, and the following can be obtained:
…………（2）
is the centroid slip angle after Lagrangian transformation.
For the transverse movement of the vehicle, the zero-change centroid side deflection angle control is adopted, the target centroid side deflection angle moment is kept to be zero, and the yaw direction gives the target yaw rate by means of the formula, and the target yaw rate is used as a reference value for yaw movement control, namely:
…………………………（3）
because each axle turning angle can be controlled independently, the invention is a multi-input single-output system, and for all-wheel steering, front-wheel steering and other steering modes conforming to the Ackerman steering relation, the invention writes the wheel turning angle of the rear axle as a function of the wheel turning angle of the front axle.
According to the geometric relationship of the multi-axle vehicle full-axle steering meeting the Ackerman steering:
…………………………………………………（4）
wherein D is fp The steering center distance isThe x-direction distance between the steering geometry center and the centroid defines:
…………………………………………………（5）
substituting the geometric relationship into a yaw dynamics model after the pull-type transformation to obtain:
………………………（6）
wherein: the operation procedure sequence a is expressed as:
………（7）
is a custom coefficient.
The invention adopts the following steering modes: when the vehicle speed is lower than the preset reference vehicle speed Vc, the rear four axles and the front two axles turn reversely to help the vehicle to turn, and when the vehicle speed is higher than the preset reference vehicle speed Vc, the rear four axles and the front two axles turn in the same direction to enhance the stability, so that the invention is represented by a coefficient related to the vehicle speed, and the definition of the coefficient is shown in a formula (8). The rear four-axle can set the steering limit value in both reverse and same-direction steering modes, and the limit value is defined by k a And k b Indicating, in particular, for steering modes above a certain reference vehicle speed Vc for which the rear axle is locked, a reference value k b Zero.
………………………………………（8）
The vehicle controller calculates the yaw angular speed of the mass center of each bridge according to the formulas (1) - (8), and outputs control signals of the electric wheel steering executing mechanism by combining the target vehicle speed and the target turning angle of each bridge. Each modular electric steering actuator cooperatively steers according to the distribution signal.
It should be understood that the sequence number of each step in the foregoing embodiment does not mean that the execution sequence of each process should be determined by the function and the internal logic, and should not limit the implementation process of the embodiment of the present invention.
The multi-axis distributed electric drive vehicle steering control method can acquire the vehicle output target acceleration, calculate the output target vehicle speed, input the vehicle speed and the turn angle signal lamp of the vehicle into the single-rail model transfer function, output the target yaw rate of the whole vehicle, and control the vehicle to run through the steering rod system of each steering bridge based on the target yaw rate, so that the reverse steering of the rear bridge and the front bridge at low speed is realized, the low-speed turning radius is reduced, and the rear bridge and the front bridge steer in the same direction at medium and high speeds. The stability of the multi-axis distributed electric drive vehicle steering control is improved, the vehicle safety is enhanced, and the driving efficiency is improved.
The elements and algorithm steps of each example described in the embodiments disclosed in the present invention related to the steering control method of the multi-axis distributed electric driven vehicle can be implemented in electronic hardware, computer software, or a combination of both, and to clearly illustrate the interchangeability of hardware and software, each example's composition and steps have been generally described in terms of functions in the above description. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The present invention relates to a multi-axis distributed electric drive vehicle steering control method, which is the unit and algorithm steps of each example described in connection with the embodiments disclosed herein, can be implemented in electronic hardware, computer software, or a combination of both, and to clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (3)
1. A method for controlling steering of a multi-axis distributed electric drive vehicle, the method comprising:
during running of the vehicle, a driver outputs target acceleration to the vehicle by controlling an accelerator pedal and a brake pedal;
the whole vehicle controller calculates and outputs a target vehicle speed;
the driver sends a turning angle signal to the vehicle by operating the steering wheel, and outputs each bridge target turning angle signal through the geometric relationship of the bridge;
the whole vehicle controller inputs the target speed of the vehicle and the target rotation angle signals of each bridge into a single-rail model transfer function, outputs the target yaw rate of the whole vehicle, and controls the running of the vehicle through the steering rod system of each steering bridge based on the target yaw rate, so that the reverse steering of the rear bridge and the front bridge at low speed is realized, the low-speed turning radius is reduced, and the rear bridge and the front bridge steer in the same direction at medium and high speeds;
in the method, a control relation of a multi-axle vehicle single-rail model is also established, and a single-rail model transfer function is established by adopting a four-wheel vehicle linear two-degree-of-freedom model method, such as a formula (1):
wherein β is the centroid slip angle of the vehicle; gamma is the centroid yaw rate of the vehicle;
C n is the cornering stiffness of the nth bridge wheel, n is an integer of 1, 2 and 3, C i Is one of n cornering stiffness;
δ n is the steering angle of the nth axle wheel, n is an integer of 1, 2 and 3, delta i One of the n wheel steering angles; x is x i For the position of the ith bridge, this value is positive when the bridge is in front of the centroid, otherwise negative; m is the mass of the whole vehicle; i z The moment of inertia is the yaw direction of the whole vehicle; v (V) x Is the vehicle x-direction speed;
and (3) carrying out Laplace transformation on the formula (1) to obtain a formula (2):
β ss is the centroid slip angle after Lagrangian transformation;
for the transverse movement of the vehicle, adopting zero centroid slip angle control, defining the moment of the target centroid slip angle to be kept zero, and obtaining a reference value of yaw movement control based on a formula (3), namely:
defining a geometric relation which satisfies the Ackerman steering and is used when the multi-axle vehicle is in full-axle steering:
wherein D is fp The steering center distance is the x-direction distance between the steering geometric center and the mass center, and the defined difference ratio is:
substituting the geometric relationship into the yaw dynamics model after the pull transformation to obtain:
the operation procedure sequence a is expressed as:
R s is a custom coefficient.
2. The multi-axis distributed electric drive vehicle steering control method according to claim 1, wherein in the method, when the vehicle speed is lower than a preset reference vehicle speed Vc, the rear four axles and the front two axles are reversely steered to assist the vehicle steering;
when the vehicle speed is higher than a preset reference vehicle speed Vc, defining a coefficient as shown in formula (8) to lead the rear four-axle and the front two-axle to steer in the same direction, setting a steering limit value of the rear four-axle in a reverse steering mode and a same-direction steering mode, wherein the limit value is represented by k a And k b A representation;
the whole vehicle controller calculates the yaw angular speed of the mass center of each bridge according to the formulas (1) to (8), and outputs control signals of the electric wheel steering executing mechanism by combining the target vehicle speed and the target turning angle of each bridge.
3. A vehicle comprising a memory, a vehicle controller, an accelerator pedal, a brake pedal, a steering wheel, and a computer program stored on the memory and operable on the vehicle controller, the vehicle controller implementing the steps of the multi-axis distributed electric drive vehicle steering control method according to any one of claims 1 to 2 when the program is executed by the vehicle controller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410001706.3A CN117485325B (en) | 2024-01-02 | 2024-01-02 | Multi-axis distributed electric drive vehicle steering control method and vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410001706.3A CN117485325B (en) | 2024-01-02 | 2024-01-02 | Multi-axis distributed electric drive vehicle steering control method and vehicle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN117485325A CN117485325A (en) | 2024-02-02 |
| CN117485325B true CN117485325B (en) | 2024-03-19 |
Family
ID=89671262
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410001706.3A Active CN117485325B (en) | 2024-01-02 | 2024-01-02 | Multi-axis distributed electric drive vehicle steering control method and vehicle |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117485325B (en) |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107804315A (en) * | 2017-11-07 | 2018-03-16 | 吉林大学 | It is a kind of to consider to drive people's car collaboration rotating direction control method that power is distributed in real time |
| CN108839656A (en) * | 2018-07-02 | 2018-11-20 | 北京理工大学 | Multiaxis distribution drives the determination method of the driving moment of articulated coach |
| CN109177744A (en) * | 2018-09-20 | 2019-01-11 | 合肥工业大学 | A kind of torque distribution control method of deviation supplementary controlled system |
| WO2019012073A1 (en) * | 2017-07-13 | 2019-01-17 | Rolf Meissner | Method for maintaining the track of a two-track vehicle |
| CN110606079A (en) * | 2019-09-18 | 2019-12-24 | 北京理工大学 | Layered control vehicle rollover prevention method and multi-shaft distributed driving vehicle |
| CN110641458A (en) * | 2019-09-18 | 2020-01-03 | 北京理工大学 | Multi-axis distributed electrically-driven vehicle reference corner control method |
| CN110696815A (en) * | 2019-11-21 | 2020-01-17 | 北京理工大学 | Prediction energy management method of network-connected hybrid electric vehicle |
| WO2021248641A1 (en) * | 2020-06-10 | 2021-12-16 | 北京理工大学 | Multi-sensor information fusion-based model adaptive lateral velocity estimation method |
| EP3944999A1 (en) * | 2020-07-31 | 2022-02-02 | MAN Truck & Bus SE | Method and driver assistance system for determining a vehicle path of a commercial vehicle |
| WO2022199991A1 (en) * | 2021-03-22 | 2022-09-29 | Zf Cv Systems Global Gmbh | Method for controlling a vehicle, control device, and vehicle |
| WO2023001100A1 (en) * | 2021-07-19 | 2023-01-26 | 中国第一汽车股份有限公司 | Distributed four-wheel drive torque control method |
| CN115817509A (en) * | 2022-11-17 | 2023-03-21 | 北京理工大学 | Multi-axis distributed driving vehicle steering auxiliary track tracking method based on AMPC |
| CN117261617A (en) * | 2023-09-26 | 2023-12-22 | 中国重汽集团济南动力有限公司 | Method, system, equipment and medium for calculating demand torque of unmanned pure electric vehicle |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9950703B2 (en) * | 2010-11-02 | 2018-04-24 | Hanwha Land Systems Co., Ltd. | Vehicle with independently driven multiple axes, and controller which independently drives multiple axles |
| WO2022104601A1 (en) * | 2020-11-18 | 2022-05-27 | 浙江吉利控股集团有限公司 | Torque distribution method for four-wheel drive of electric vehicle, and system and vehicle |
-
2024
- 2024-01-02 CN CN202410001706.3A patent/CN117485325B/en active Active
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019012073A1 (en) * | 2017-07-13 | 2019-01-17 | Rolf Meissner | Method for maintaining the track of a two-track vehicle |
| CN107804315A (en) * | 2017-11-07 | 2018-03-16 | 吉林大学 | It is a kind of to consider to drive people's car collaboration rotating direction control method that power is distributed in real time |
| CN108839656A (en) * | 2018-07-02 | 2018-11-20 | 北京理工大学 | Multiaxis distribution drives the determination method of the driving moment of articulated coach |
| CN109177744A (en) * | 2018-09-20 | 2019-01-11 | 合肥工业大学 | A kind of torque distribution control method of deviation supplementary controlled system |
| CN110606079A (en) * | 2019-09-18 | 2019-12-24 | 北京理工大学 | Layered control vehicle rollover prevention method and multi-shaft distributed driving vehicle |
| CN110641458A (en) * | 2019-09-18 | 2020-01-03 | 北京理工大学 | Multi-axis distributed electrically-driven vehicle reference corner control method |
| CN110696815A (en) * | 2019-11-21 | 2020-01-17 | 北京理工大学 | Prediction energy management method of network-connected hybrid electric vehicle |
| WO2021248641A1 (en) * | 2020-06-10 | 2021-12-16 | 北京理工大学 | Multi-sensor information fusion-based model adaptive lateral velocity estimation method |
| EP3944999A1 (en) * | 2020-07-31 | 2022-02-02 | MAN Truck & Bus SE | Method and driver assistance system for determining a vehicle path of a commercial vehicle |
| WO2022199991A1 (en) * | 2021-03-22 | 2022-09-29 | Zf Cv Systems Global Gmbh | Method for controlling a vehicle, control device, and vehicle |
| WO2023001100A1 (en) * | 2021-07-19 | 2023-01-26 | 中国第一汽车股份有限公司 | Distributed four-wheel drive torque control method |
| CN115817509A (en) * | 2022-11-17 | 2023-03-21 | 北京理工大学 | Multi-axis distributed driving vehicle steering auxiliary track tracking method based on AMPC |
| CN117261617A (en) * | 2023-09-26 | 2023-12-22 | 中国重汽集团济南动力有限公司 | Method, system, equipment and medium for calculating demand torque of unmanned pure electric vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| CN117485325A (en) | 2024-02-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109849899B (en) | Electro-hydraulic composite vehicle body stability control system and method for electric wheel vehicle | |
| KR101083946B1 (en) | Vehicle drive apparatus | |
| CN110466604B (en) | Control method for differential driving steering and stability of electric automobile driven by hub motor | |
| Velenis et al. | Steady-state cornering equilibria and stabilisation for a vehicle during extreme operating conditions | |
| CN110466602A (en) | The timesharing four-wheel steering system and its control method of hub motor driven electric vehicle | |
| CN114179905B (en) | Control method of double-mode rear wheel active steering system | |
| Irie et al. | 4WS technology and the prospects for improvement of vehicle dynamics | |
| CN113002324B (en) | Electronic differential system of four-wheel independent driving and independent steering electric automobile | |
| WO2022266824A1 (en) | Steering control method and apparatus | |
| CN112319602B (en) | 6X4 electric automobile chassis system capable of realizing all-wheel steering and steering control method | |
| JP7471517B2 (en) | Electric vehicle four-wheel drive torque distribution method, system and vehicle | |
| CN112016155B (en) | All-electric drive distributed unmanned vehicle motion simulation platform and design method thereof | |
| Li et al. | Adaptive sliding mode control of lateral stability of four wheel hub electric vehicles | |
| CN117485325B (en) | Multi-axis distributed electric drive vehicle steering control method and vehicle | |
| CN114044003B (en) | Tracking control method for front-rear double-axle steering vehicle | |
| Shen et al. | Active rear wheel steering control strategy research based on H∞ optimal control | |
| Lu et al. | Research on Handling Stability Control Strategy of Distributed Drive Electric Vehicle | |
| Zhang et al. | Fuzzy neural network simulation of vehicle yaw rate control based on PID | |
| CN113085836A (en) | Vehicle roll control method | |
| Zheng et al. | Variable steering ratio design for vehicle steer-by-wire system with joystick | |
| Gang et al. | Coordinated Vehicle Lateral Stability Control Based on Direct Yaw Moment and Engine Torque Regulation under Complicated Road Conditions | |
| Huh et al. | Development of a simulation tool for the cornering performance analysis of 6WD/6WS vehicles | |
| Ozatay et al. | Enhancement of vehicle handling using four wheel steering control strategy | |
| Chen et al. | Coupled Lateral and Longitudinal Control for Trajectory Tracking, Lateral Stability, and Rollover Prevention of High-Speed Automated Vehicles Using Minimum-Time Model Predictive Control | |
| Zheng et al. | A humanoid collision-avoidance strategy considering a large sideslip angle state |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |