Commercial vehicle transverse control method and system for high-speed curve scene

Abstract

The invention discloses a commercial vehicle transverse control method and system for a high-speed curve scene, and belongs to the field of intelligent network connection, and the method comprises the steps: calculating a target curvature and a target curvature change rate of a projection curve containing each projection point based on the projection information of the projection point corresponding to each preview point; when the current working condition is the straightway driving working condition, the basic feed-forward compensation amount is obtained according to the target curvature, and transverse control is carried out; and when the current working condition is a curve related working condition, after a basic feed-forward compensation amount is obtained according to the target curvature, a compensation gain is obtained by looking up a table by using the target curvature and the target curvature change rate, and compensated feed-forward compensation is obtained based on the target curvature change rate and the compensation gain for transverse control. According to the invention, the transverse control of the vehicle can be realized under the scenes of high-speed straight lanes, sharp turns and continuous curves, and the feedback control quantity based on errors is subjected to feed-forward compensation according to the curvature condition of the projection curve corresponding to the preview point, so that the transverse stability is ensured, and the lane centering of the vehicle under the high-speed full scene is realized.

Description

Technical Field

[0001] The present application relates to the field of intelligent networking, and specifically to a commercial vehicle lateral control method and system for high-speed curve scenarios. Background Art

[0002] Rollover accidents are extremely dangerous, and minimizing the probability of rollover accidents is an important research area in automotive technology. Currently, domestic and foreign vehicle manufacturers generally reduce the body roll angle when the vehicle turns by limiting the center of gravity height and adopting lateral stabilizer bars to suppress the probability of vehicle rollover. However, this measure cannot actively control the vehicle's driving status and cannot minimize the probability of rollover accidents.

[0003] Chinese patent application CN113311698A discloses a lane keeping control method. The method determines the vehicle's preview distance based on vehicle speed; determines the vehicle's state error feedback and road curvature compensation based on the preview distance and lane marking information; determines the vehicle's state error control based on control parameters and the state error feedback; and controls vehicle steering based on the state error control and road curvature compensation. This method continuously determines the appropriate preview point based on varying vehicle speeds during driving, and calculates control compensation based on the preview distance and lane marking parameters, improving the robustness of the lane keeping control algorithm.

[0004] This method is a common lane-keeping lateral control strategy currently used in the industry. It lacks precise control strategies for sharp turns, S-curves, and in-and-out corners, and cannot guarantee lateral control accuracy in these situations. This can lead to the vehicle deviating from or running out of its lane, posing a serious safety risk. Summary of the Invention

[0005] The present application provides a commercial vehicle lateral control method and system for high-speed curve scenarios, which can solve the technical problem in the prior art that conventional means cannot be used to intervene in lateral rollover in the intelligent driving state.

[0006] In a first aspect, embodiments of the present application provide a commercial vehicle lateral control method for high-speed curve scenarios, the method comprising: Based on the preview distance of each preview point, calculate the projection point of each preview point on the reference line to obtain corresponding projection information; the projection information includes the coordinates of the projection point in the rectangular coordinate system, the coordinates in the Frenet coordinate system, the heading angle of the projection point, and the curvature of the projection point; Based on each projection information, calculate the target curvature and target curvature change rate of the projection curve including each projection point; When the current working condition is a straight-line driving condition, a basic feedforward compensation amount is obtained according to the target curvature, and lateral control is performed in combination with the basic feedforward compensation amount; When the current operating condition is a curve, a straight-line entry into a curve, or a straight-line entry into a straight-line condition, after obtaining a basic feedforward compensation amount based on the target curvature, a compensation gain is obtained by looking up the target curvature and the target curvature change rate. Based on the target curvature change rate and the compensation gain, a secondary feedforward compensation amount is obtained, and lateral control is performed by combining the basic and secondary feedforward compensation amounts.

[0007] In combination with the first aspect, in one embodiment, the method further includes: According to the real-time vehicle speed, obtain the preview time of at least three preview points; According to the curvature of the real-time reference line, the time-distance coefficient of each preview point is obtained; According to the real-time vehicle speed, preview time and time-distance coefficient, the preview distance of each preview point is obtained.

[0008] In conjunction with the first aspect, in one embodiment, the preview distance is calculated using the following formula: goal_dist = gain_tgap_curvature×tgap×v; Among them, goal_dist represents the preview distance, gain_tgap_curvature represents the time-gap coefficient, tgap represents the preview time, and v represents the real-time vehicle speed.

[0009] In conjunction with the first aspect, in one embodiment, calculating the projection point of each preview point on the reference line based on the preview distance of each preview point to obtain corresponding projection information specifically includes the following steps: Determine whether the projection point of the preview point falls within the reference line. If so, when the projection point coincides with the trajectory point of the reference line, use the trajectory point as the projection point to obtain the projection information. When the projection point does not coincide with the trajectory point of the reference line, perform linear interpolation between two trajectory points adjacent to the projection point based on the projection point to obtain the projection information of the projection point. If not, update the trajectory point closest to the projection point at the end of the reference line to the projection point to obtain the projection information.

[0010] In combination with the first aspect, in one embodiment, the method further includes: According to the curvature of all projection points, a real-time operating condition type is obtained; the operating condition type is a straight-line driving condition, a curve driving condition, a straight-line-entering-curve condition, or a curve-entering-straight-line driving condition; When the curvature of the projection point falls within the straight road curvature threshold range, it is determined that the current driving condition is a straight road; When the curvature of the projection point falls outside the straight curvature threshold range, the positive and negative changes of the target curvature and the target curvature change rate are combined to determine whether the current driving condition is a curve, a straight-line entry into a curve, or a curve-entry into a straight-line condition.

[0011] In combination with the first aspect, in one embodiment, the target curvature is obtained by averaging the projection point curvatures of each projection point; the curvature of each projection point is calculated using the following formula: ; Where curvature represents the curvature of the projection point, x represents the x-coordinate of the projection point, and y represents the y-coordinate of the projection point.

[0012] In combination with the first aspect, in one embodiment, the target curvature change rate is obtained by averaging the absolute values ​​of the differences between the projection point curvatures of the projection points and the target curvature.

[0013] In combination with the first aspect, in one embodiment, the basic feedforward compensation is calculated using the following formula: FeedforwardValue1 = atan(L×tar_curvature); Among them, FeedforwardValue1 represents the basic feedforward compensation, L represents the vehicle wheelbase, and tar_curvature represents the target curvature; The secondary feedforward compensation is calculated using the following formula: FeedforwardValue2 = k_curv×diff_curv; Among them, FeedforwardValue2 represents the quadratic feedforward compensation amount, k_curv represents the compensation gain, and diff_curv represents the target curvature change rate.

[0014] In conjunction with the first aspect, in one embodiment, performing lateral control in conjunction with the basic feedforward compensation specifically includes: According to the lateral error and heading error, the feedback compensation amount is obtained; The basic feedforward compensation amount and feedback compensation amount are summed to obtain a lateral control command, and lateral control is performed according to the lateral control command; The lateral control is performed by combining the basic and the secondary feedforward compensation, specifically including: According to the lateral error and heading error, the feedback compensation amount is obtained; The basic feedforward compensation, the secondary feedforward compensation and the feedback compensation are summed to obtain a lateral control instruction, and lateral control is performed according to the lateral control instruction.

[0015] In a second aspect, an embodiment of the present application provides a commercial vehicle lateral control system for high-speed curve scenarios, the system comprising: A projection point calculation module is used to calculate the projection point of each preview point on the reference line based on the preview distance of each preview point, and obtain corresponding projection information; the projection information includes the coordinates of the projection point in the rectangular coordinate system, the coordinates in the Frenet coordinate system, the heading angle of the projection point, and the curvature of the projection point; A target curve calculation module is used to calculate the target curvature and target curvature change rate of the projection curve containing each projection point based on each projection information; A lateral control module, which is used to obtain a basic feedforward compensation amount based on the target curvature when the current working condition is a straight-line driving condition, and perform lateral control in combination with the basic feedforward compensation amount; When the current operating condition is a curve, a straight-line entry into a curve, or a straight-line entry into a straight-line condition, after obtaining a basic feedforward compensation amount based on the target curvature, a compensation gain is obtained by looking up the target curvature and the target curvature change rate. Based on the target curvature change rate and the compensation gain, a secondary feedforward compensation amount is obtained, and lateral control is performed by combining the basic and secondary feedforward compensation amounts.

[0016] The beneficial effects of the technical solutions provided in the embodiments of the present application include: By calculating the projection points of each preview point on the reference line, the corresponding projection information is obtained, and the curvature of the target curve containing each projection point is calculated based on the projection information, including the target curvature and the target curvature change rate. When the current working condition is a straight-line driving condition, the basic compensation amount is obtained according to the target curvature, and the error feedback lateral control amount of the lateral control system is compensated according to the basic feedforward compensation amount, thereby improving the final lateral control accuracy; when the current working condition is a curve driving condition, a straight-line entering a curve condition, or a curve-entering a straight-line condition, after obtaining the basic compensation amount according to the target curvature, the compensation gain is obtained by looking up the table according to the curvature condition, and based on The target curvature change rate and the compensation gain are used to obtain a quadratic feedforward compensation. The error feedback lateral control amount of the lateral control system is compensated based on the basic and quadratic feedforward compensation amounts, thereby improving the ultimate lateral control accuracy of commercial vehicles in high-speed sharp bends and continuous bends. Ultimately, feedforward compensation is achieved for the traditional lateral control amount, thereby ensuring the lateral stability of the vehicle. The entire process does not require any relevant input from manual driving and does not involve systems such as emergency braking. In normal intelligent driving conditions, by configuring multiple preview points and calculating the feedforward compensation amount, the conventional lateral control amount is compensated according to the feedforward compensation amount, thereby improving the lateral stability of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of an embodiment of a commercial vehicle lateral control method for a high-speed curve scenario according to the present application; Figure 2 This is a schematic diagram of the functional modules of an embodiment of a commercial vehicle lateral control system for high-speed curve scenarios in this application. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0019] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0020] In a first aspect, an embodiment of the present application provides a commercial vehicle lateral control method for high-speed curve scenarios.

[0021] In one embodiment, referring to Figure 1 , Figure 1 This is a flow chart of an embodiment of a commercial vehicle lateral control method for high-speed curve scenes in this application. Figure 1 As shown in Figure 1, the lateral control method for commercial vehicles in high-speed curve scenarios includes: Step S1: Obtain preview times of at least three preview points based on the real-time vehicle speed.

[0022] Step S2: Obtain the time-to-distance coefficient of each preview point based on the curvature of the real-time reference line.

[0023] Step S3: Obtain the preview distance of each preview point according to the real-time vehicle speed, preview time, and time-to-distance coefficient.

[0024] Step S4: Based on the preview distance of each preview point, calculate the projection point of each preview point on the reference line to obtain corresponding projection information. The above projection information includes the coordinates of the projection point in the rectangular coordinate system, the coordinates in the Frenet coordinate system, the heading angle of the projection point, and the curvature of the projection point.

[0025] Step S5: Based on each projection information, calculate the target curvature and target curvature change rate of the projection curve including each projection point.

[0026] Step S6: Determine whether the current working condition is a straight-line driving condition, a straight-line entering a curve condition, or a curve-entering straight-line driving condition: If yes, go to step S7.

[0027] If not, go to step S8.

[0028] Step S7: Obtain a basic feedforward compensation amount according to the target curvature, and perform lateral control in combination with the basic feedforward compensation amount.

[0029] In step S8, after obtaining the basic feedforward compensation according to the target curvature, the compensation gain is obtained by looking up the table using the target curvature and the target curvature change rate. Based on the target curvature change rate and the compensation gain, the quadratic feedforward compensation is obtained, and the basic and quadratic feedforward compensations are combined for lateral control.

[0030] In this embodiment, the projection points of each preview point on the reference line are calculated to obtain corresponding projection information. The curvature of the target curve containing each projection point is calculated based on the projection information, including the target curvature and the target curvature change rate. When the current working condition is a straight-line driving condition, a basic compensation amount is obtained based on the target curvature, and the error feedback lateral control amount of the lateral control system is compensated based on the basic feedforward compensation amount, thereby improving the final lateral control accuracy. When the current operating condition is a curve driving condition, a straight-line exit into a curve condition, or a curve-line exit into a straight-line condition, after obtaining a basic compensation amount according to the target curvature, a compensation gain is obtained by looking up a table according to the curvature condition, and a secondary feedforward compensation amount is obtained based on the target curvature change rate and the compensation gain. The error feedback lateral control amount of the lateral control system is compensated according to the basic and secondary feedforward compensation amounts, thereby improving the final lateral control accuracy of commercial vehicles in high-speed sharp bends and continuous bends. Ultimately, feedforward compensation of the traditional lateral control amount is achieved, thereby ensuring the lateral stability of the vehicle. The entire process does not require any relevant input from manual driving, and does not involve systems such as emergency braking. In the normal intelligent driving state, by configuring multiple preview points and calculating the feedforward compensation amount, the conventional lateral control amount is compensated according to the feedforward compensation amount, thereby improving the lateral stability of the vehicle.

[0031] This solution primarily improves upon the preview feedforward method, proposing a dual feedforward compensation strategy based on the curvature and curvature change rate of multiple preview points for different road types. This strategy ensures the vehicle's lateral control accuracy in both high-speed straights and curves, ensuring safe lane centering.

[0032] In one specific embodiment, the system first receives lane reference line trajectory point information output by the upstream perception and fusion module, calculates a preview time based on the real-time vehicle speed, and calculates a time-to-distance coefficient based on the real-time reference line curvature. The preview distance is then calculated based on the preview time, real-time vehicle speed, and time-to-distance coefficient. The preview projection point information on the reference line is then calculated based on the preview distance. The real-time reference line curvature is the overall curvature of the reference line detected in real time by the perception and fusion module. The reference line is typically the road centerline, and this curvature may or may not be the same as the curvature of the subsequently calculated projection point.

[0033] Secondly, based on the preview projection point information at near, medium and long distances, the vehicle’s current road condition is identified to determine whether the vehicle is on a straight road, a curve, or entering or exiting a curve.

[0034] Next, based on the vehicle's operating conditions, the actual speed and the projection information corresponding to the preview point are used to design the curve compensation (also known as the basic feedforward compensation) and preview curvature feedforward compensation (also known as the secondary feedforward compensation) for different operating conditions, resulting in a comprehensive feedforward compensation. For straight-line driving conditions, only the basic feedforward compensation needs to be calculated.

[0035] Secondly, the lateral error and heading error calculated by the upstream lateral control system are obtained, and the feedback control amount is calculated by combining the feedback control law.

[0036] Finally, the feedback control amount and feedforward compensation amount are combined to calculate the final lateral control instruction, and the steering message is sent through the CAN bus to control the lateral control system to realize the vehicle lateral control function.

[0037] Furthermore, in one embodiment, the preview distance is calculated using the following formula (1): goal_dist = gain_tgap_curvature×tgap×v(1).

[0038] Among them, goal_dist represents the preview distance, gain_tgap_curvature represents the time-gap coefficient, tgap represents the preview time, and v represents the real-time vehicle speed.

[0039] In this embodiment, a relationship table between the preview time and the real-time vehicle speed, as well as a relationship table between the preview time coefficient and the curvature of the real-time reference line are pre-established. For example, the time tables for setting the near, mid, and far preview points are Table_tgap_near_spd, Table_tgap_mid_spd, and Table_tgap_far_spd, respectively, and the gain table for the preview time coefficient and the road curvature is Table_gain_tgap_curvature.

[0040] To calculate the preview times for near, medium, and far distances based on the real-time vehicle speed and the curvature of the real-time reference line, first obtain the vehicle's real-time speed. Then, look up the tables Table_tgap_near_spd, Table_tgap_mid_spd, and Table_tgap_far_spd to obtain the preview times tgap_near, tgap_mid, and tgap_far for near, medium, and far distances, respectively. Then, obtain the curvature of the real-time reference line and look up the table Table_gain_tgap_curvature to obtain the coefficient gain_tgap_curvature that determines the preview time.

[0041] Finally, calculate the preview distance, where the preview distance of the close-range preview point (referred to as near distance) is goal_dist_near = gain_tgap_curvature*tgap_near*v, the preview distance of the medium-range preview point (referred to as medium distance) is goal_dist_mid = gain_tgap_curvature*tgap_mid*v, and the preview distance of the far-range preview point (referred to as far distance) is goal_dist_far = gain_tgap_curvature*tgap_far*v.

[0042] Furthermore, in one embodiment, the above-mentioned calculation of the projection point of each preview point on the reference line based on the preview distance of each preview point to obtain corresponding projection information specifically includes the following steps: Determine whether the projection of the preview point falls within the reference line. If so, if the projection point coincides with a trajectory point of the reference line, use the trajectory point as the projection point to obtain the aforementioned projection information. If the projection point does not coincide with a trajectory point of the reference line, linear interpolation is performed between the two adjacent trajectory points based on the projection point to obtain the aforementioned projection information. If not, update the trajectory point closest to the projection point at the end of the reference line to obtain the aforementioned projection information.

[0043] In this embodiment, the method for calculating the projection point of the near, medium and long distance preview aiming points on the reference line is the same, and the calculation of the projection point of the near distance preview aiming point on the reference line is taken as an example for description.

[0044] First, calculate the position of the preview point on the reference line (here based on the Frenet coordinate system): s_near = reference line starting point + preview distance.

[0045] Secondly, use s_near to find the reference line trajectory points and find the index positions index1 and index2 of the two closest trajectory points.

[0046] Again, if the projection point does not coincide with the trajectory point of the reference line and the projection point falls within the range of the reference line (the fusion perception module can only perceive a section of the reference line within the preset range in front of the vehicle. Therefore, the projection point may fall inside or outside the reference line), linear interpolation is performed between the trajectory points index1 and index2 through s_near to obtain the projection information NearPoint(x, y, h, c, s, l), where x and y are the coordinates of the projection point in the rectangular coordinate system, s and l are the coordinates of the projection point in the Frenet coordinate system, h represents the heading angle of the projection point, and c represents the curvature of the projection point.

[0047] If s_near is outside the reference line, the projection point is the one with the closest distance between the two ends of the reference line.

[0048] Refer to the near-distance calculation method to obtain the projection information MidPoint(x, y, h, c, s, l) of the mid-distance projection point and the projection information FarPoint(x, y, h, c, s, l) of the far-distance projection point.

[0049] Furthermore, in one embodiment, the above method further includes: According to the curvature of all projection points, the real-time operating condition type is obtained, which is a straight-line driving condition, a curve driving condition, a straight-line-entering-curve condition, or a curve-entering-straight-line driving condition.

[0050] When the curvature of the projection point falls within the straight road curvature threshold range, it is determined that the current driving condition is a straight road.

[0051] When the curvature of the projection point falls outside the straight curvature threshold range, the positive and negative changes of the target curvature and the target curvature change rate are combined to determine whether the current driving condition is a curve, a straight-line entry into a curve, or a curve-entry into a straight-line condition.

[0052] In this embodiment, in view of the impact of highways on lateral control, the vehicle operating conditions on highways are divided into four types: straight-line driving condition, curve driving condition, exiting a straight road into a curve condition, and exiting a curve into a straight road condition.

[0053] Set the straight road curvature threshold, curv_threshold. When the curvature is within the threshold range, it is identified as a straight road; the rest are curves. When determining whether the current operating condition is a curve, exiting a straight road into a curve, or exiting a curve into a straight road, the reference line has positive and negative properties in the Frenet coordinate system (generally positive on the left and negative on the right). Accordingly, the curvature of each projection point also has positive and negative properties. Based on the numerical changes and positive and negative changes of each projection point from near to far, and the curvature of the reference line, the current operating condition can be determined.

[0054] In a specific embodiment, if 、 and , it is determined that the vehicle is in a straight road condition.

[0055] like and , it is determined that the vehicle is leaving the straight road and entering the curve.

[0056] like and , it is determined that the vehicle is exiting the curve and entering the straight road condition.

[0057] In addition to the above situations, it is determined that the vehicle is in a curve condition.

[0058] Furthermore, in one embodiment, the target curvature is obtained by averaging the curvatures of the projection points of each projection point. The curvatures of each projection point are calculated using the following formula (2): (2).

[0059] Where curvature represents the curvature of the projection point, x represents the x-coordinate of the projection point, and y represents the y-coordinate of the projection point.

[0060] Furthermore, in one embodiment, the target curvature change rate is obtained by averaging the absolute values ​​of the differences between the projection point curvatures of the projection points and the target curvature.

[0061] Furthermore, in one embodiment, the above-mentioned basic feedforward compensation is calculated using the following formula (3): FeedforwardValue1 = atan(L×tar_curvature) (3).

[0062] Among them, FeedforwardValue1 represents the basic feedforward compensation amount, L represents the preset distance, and tar_curvature represents the target curvature.

[0063] The above-mentioned quadratic feedforward compensation is calculated using the following formula (4): FeedforwardValue2 = k_curv×diff_curv(4).

[0064] Among them, FeedforwardValue2 represents the quadratic feedforward compensation amount, k_curv represents the compensation gain, and diff_curv represents the target curvature change rate.

[0065] In this embodiment, the three preview points of near, middle and far are still taken as an example. The road curvature (the curvature between the preview points) is calculated by combining the projection information corresponding to the three preview points: .

[0066] .

[0067] .

[0068] in, 、 as well as They are the curvatures of the projection points corresponding to the three preview points near, middle and far, respectively. and is the xy coordinate of the close-range preview point, and is the xy coordinate of the mid-range preview point, and The xy coordinates of the long-range preview point.

[0069] The target curvature is obtained by averaging the curvatures of the three projection points: tar_curvature = avg(curvature_near + curvature_mid + curvature_far).

[0070] Combined with the projection information corresponding to the three preview points, the target curvature change rate is calculated: diff_curv_near = tar_curvature - curvature_near.

[0071] diff_curv_far = curvature_far - tar_curvature.

[0072] diff_curv = (diff_curv_mid+ diff_curv_far) / 2.

[0073] Where diff_curv is the target curvature change rate.

[0074] When the vehicle is on a straight road, the target curvature is used to calculate the basic feedforward compensation.

[0075] When the vehicle is on a curve, the curvature of the road may change, so the curvature change compensation term FeedforwardValue2 should be calculated based on the target curvature feedforward compensation. Finally, the front wheel angle is corrected according to the curvature trend, and the steering wheel angle is further corrected.

[0076] When the vehicle is on a straight road entering a curve, consider adding a curvature change compensation term, FeedforwardValue2, to the target curvature feedforward compensation. Finally, the steering wheel angle should be increased in the direction of the curve.

[0077] When the vehicle is entering a curve from a straight road, the compensation term FeedforwardValue2 that eliminates the curvature change is considered based on the target curvature feedforward compensation. Finally, the steering wheel angle should be reduced in the direction of the curve.

[0078] In a specific embodiment, a two-dimensional coefficient table Table_gain_curv of target curvature and target curvature change rate is established.

[0079] By looking up the table Table_gain_curv based on the target curvature tar_curvature and the target curvature change rate diff_curv, the compensation gain k_curv = Table_gain_curv(tar_curvature,diff_curv) is obtained. Calculate the feedforward compensation for the curvature change: FeedforwardValue2 = k_curv * diff_curv.

[0080] Comprehensively solve the curve feedforward compensation amount: FeedforwardValue = FeedforwardValue1+FeedforwardValue2.

[0081] Furthermore, in one embodiment, the lateral control is performed in combination with the basic feedforward compensation, specifically including: The feedback compensation amount is obtained according to the lateral error and heading error.

[0082] The basic feedforward compensation and feedback compensation are summed to obtain a lateral control instruction, and lateral control is performed according to the lateral control instruction.

[0083] The above combined basic and quadratic feedforward compensation for lateral control includes: The feedback compensation amount is obtained according to the lateral error and heading error.

[0084] The basic feedforward compensation, the secondary feedforward compensation and the feedback compensation are summed to obtain a lateral control instruction, and lateral control is performed according to the lateral control instruction.

[0085] In this embodiment, the upstream planning module calculates the lateral error and the heading error through the relative relationship between the vehicle position and the target trajectory (reference line or planned trajectory).

[0086] According to the lateral error and the lateral error change rate, the lateral control gain coefficient is obtained by looking up the table. Combining the lateral error, the error change rate and the gain coefficient, CtrlValue_laterr is calculated.

[0087] According to the heading error and the heading error change rate, the heading control gain coefficient is obtained by looking up the table. Combining the heading error, the error change rate and the gain coefficient, CtrlValue_yawerr is calculated.

[0088] Calculate the control command based on the lateral error and heading error: FeedbackValue = CtrlValue_later + CtrlValue_yawerr.

[0089] Finally, the feedforward compensation and feedback control are combined to obtain the lateral control command to control the steering wheel.

[0090] Specifically, calculate the lateral control command: LatCtrlValue = FeedforwardValue +FeedbackValue.

[0091] Control commands are rate-limited. Considering the maximum angular velocity that the steering gear can execute and steering safety in high-speed scenarios, a table (Table_SteerSpd_limit) for steering wheel angular rate changes based on vehicle speed is designed. Based on the real-time vehicle speed, the maximum allowable rotational speed at that speed is retrieved from the table (Table_SteerSpd_limit) to limit the rate of change of control commands.

[0092] Limit control commands to their extreme values. Considering steering safety in high-speed scenarios, design the maximum allowable steering wheel angle table Table_SteerAngle_limit for vehicle speed changes.

[0093] According to the real-time vehicle speed, the table Table_SteerAngle_limit is looked up to obtain the maximum angle allowed at the vehicle speed, and the extreme value of the control command is limited to obtain the target steering angle command TargetCtrlValue.

[0094] The steering command is sent. The steering command TargetCtrlValue after the limit processing is packaged according to the message format and sent to the steering device through the bus to achieve lateral control of the autonomous driving vehicle.

[0095] In summary, the present invention proposes a feedforward compensation strategy, including: identifying the road conditions ahead of the vehicle in advance, and identifying sharp bends and cornering scenarios. Pre-aiming points are designed based on vehicle speed and road curvature, the turning radius of the road ahead is calculated based on the preview point information, and the feedforward compensation amount is calculated using a vehicle dynamics model. For sharp bends and cornering scenarios, where the road curvature changes significantly, a feedforward compensation strategy targeting the curvature change rate is added. By online identification of the curvature changes of the road ahead, the steering wheel is compensated in advance, and the vehicle is controlled to quickly follow the reference line trajectory to achieve the goal of centering the vehicle.

[0096] Secondly, the embodiments of the present application also provide a commercial vehicle lateral control system for high-speed curve scenarios.

[0097] In one embodiment, referring to Figure 2 , Figure 2 This is a functional module diagram of an embodiment of a commercial vehicle lateral control system for high-speed curve scenarios in this application. Figure 2 As shown in the figure, the commercial vehicle lateral control system for high-speed curve scenarios includes: Projection point calculation module 1 is used to calculate the projection point of each preview point on the reference line based on the preview distance of each preview point, and obtain corresponding projection information. The above projection information includes the coordinates of the projection point in the rectangular coordinate system, the coordinates in the Frenet coordinate system, the heading angle of the projection point, and the curvature of the projection point.

[0098] The target curve calculation module 2 is used to calculate the target curvature and target curvature change rate of the projection curve containing each projection point based on each projection information.

[0099] The lateral control module 3 is used to obtain a basic feedforward compensation amount according to the target curvature when the current working condition is a straight-line driving condition, and perform lateral control in combination with the basic feedforward compensation amount.

[0100] When the current operating condition is a curve, a straight-line entry into a curve, or a straight-line entry into a straight-line condition, after obtaining a basic feedforward compensation amount based on the target curvature, a compensation gain is obtained by looking up the target curvature and the target curvature change rate. Based on the target curvature change rate and the compensation gain, a secondary feedforward compensation amount is obtained, and lateral control is performed by combining the basic and secondary feedforward compensation amounts.

[0101] Among them, the functional implementation of each module in the above-mentioned commercial vehicle lateral control system for high-speed curve scenarios corresponds to the various steps in the above-mentioned commercial vehicle lateral control method embodiment for high-speed curve scenarios, and their functions and implementation processes will not be repeated here one by one.

[0102] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0103] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings 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 limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit the "first", "second" and "third" to different types.

[0104] In the description of the embodiments of this application, the words "exemplary," "for example," or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary," "for example," or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "for example," or "for example" is intended to present the relevant concepts in a concrete manner.

[0105] In the description of the embodiments of the present application, unless otherwise specified, " / " means or. For example, A / B can mean A or B. The "and / or" in the text is merely a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "plurality" means two or more than two.

[0106] In some processes described in the embodiments of the present application, multiple operations or steps are included that appear in a specific order. However, it should be understood that these operations or steps may not be performed in the order in which they appear in the embodiments of the present application or may be performed in parallel. The sequence numbers of the operations are only used to distinguish between different operations, and the sequence numbers themselves do not represent any order of execution. In addition, these processes may include more or fewer operations, and these operations or steps may be performed in sequence or in parallel, and these operations or steps may be combined.

[0107] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes a number of instructions for enabling a terminal device to execute the above-mentioned methods of each embodiment of the present application.

[0108] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A commercial vehicle lateral control method for high-speed curve scenarios, characterized by: The method comprises: Based on the preview distance of each preview point, calculate the projection point of each preview point on the reference line to obtain corresponding projection information; the projection information includes the coordinates of the projection point in the rectangular coordinate system, the coordinates in the Frenet coordinate system, the heading angle of the projection point, and the curvature of the projection point; Based on each projection information, calculate the target curvature and target curvature change rate of the projection curve including each projection point; When the current working condition is a straight-line driving condition, a basic feedforward compensation amount is obtained according to the target curvature, and lateral control is performed in combination with the basic feedforward compensation amount; When the current operating condition is a curve, a straight-line entry into a curve, or a straight-line entry into a straight-line condition, after obtaining a basic feedforward compensation amount based on the target curvature, a compensation gain is obtained by looking up the target curvature and the target curvature change rate. Based on the target curvature change rate and the compensation gain, a secondary feedforward compensation amount is obtained, and lateral control is performed by combining the basic and secondary feedforward compensation amounts.

2. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The method further comprises: According to the real-time vehicle speed, obtain the preview time of at least three preview points; According to the curvature of the real-time reference line, the time-distance coefficient of each preview point is obtained; According to the real-time vehicle speed, preview time and time-distance coefficient, the preview distance of each preview point is obtained.

3. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The preview distance is calculated using the following formula: goal_dist = gain_tgap_curvature×tgap×v; Among them, goal_dist represents the preview distance, gain_tgap_curvature represents the time-gap coefficient, tgap represents the preview time, and v represents the real-time vehicle speed.

4. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The method of calculating the projection points of each preview point on the reference line based on the preview distance of each preview point to obtain corresponding projection information specifically includes the following steps: Determine whether the projection point of the preview point falls within the reference line. If so, when the projection point coincides with the trajectory point of the reference line, use the trajectory point as the projection point to obtain the projection information. When the projection point does not coincide with the trajectory point of the reference line, perform linear interpolation between two trajectory points adjacent to the projection point based on the projection point to obtain the projection information of the projection point. If not, update the trajectory point closest to the projection point at the end of the reference line to the projection point to obtain the projection information.

5. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The method further comprises: According to the curvature of all projection points, a real-time operating condition type is obtained; the operating condition type is a straight-line driving condition, a curve driving condition, a straight-line-entering-curve condition, or a curve-entering-straight-line driving condition; When the curvature of the projection point falls within the straight road curvature threshold range, it is determined that the current driving condition is a straight road; When the curvature of the projection point falls outside the straight curvature threshold range, the positive and negative changes of the target curvature and the target curvature change rate are combined to determine whether the current driving condition is a curve, a straight-line entry into a curve, or a curve-entry into a straight-line condition.

6. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The target curvature is obtained by averaging the curvatures of the projection points of each projection point; the curvature of each projection point is calculated using the following formula: ； Where curvature represents the curvature of the projection point, x represents the x-coordinate of the projection point, and y represents the y-coordinate of the projection point.

7. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The target curvature change rate is obtained by averaging the absolute values ​​of the differences between the projection point curvature and the target curvature of each projection point.

8. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The basic feedforward compensation is calculated using the following formula: FeedforwardValue1 = atan(L×tar_curvature); Among them, FeedforwardValue1 represents the basic feedforward compensation, L represents the vehicle wheelbase, and tar_curvature represents the target curvature; The secondary feedforward compensation is calculated using the following formula: FeedforwardValue2 = k_curv×diff_curv; Among them, FeedforwardValue2 represents the quadratic feedforward compensation amount, k_curv represents the compensation gain, and diff_curv represents the target curvature change rate.

9. The commercial vehicle lateral control method for high-speed curve scenarios according to claim 1, characterized in that: The lateral control is performed in combination with the basic feedforward compensation, specifically including: According to the lateral error and heading error, the feedback compensation amount is obtained; The basic feedforward compensation amount and feedback compensation amount are summed to obtain a lateral control command, and lateral control is performed according to the lateral control command; The lateral control is performed by combining the basic and the secondary feedforward compensation, specifically including: According to the lateral error and heading error, the feedback compensation amount is obtained; The basic feedforward compensation, the secondary feedforward compensation and the feedback compensation are summed to obtain a lateral control instruction, and lateral control is performed according to the lateral control instruction.

10. A commercial vehicle lateral control system for high-speed curve scenarios, characterized by: The system comprises: A projection point calculation module is used to calculate the projection point of each preview point on the reference line based on the preview distance of each preview point, and obtain corresponding projection information; the projection information includes the coordinates of the projection point in the rectangular coordinate system, the coordinates in the Frenet coordinate system, the heading angle of the projection point, and the curvature of the projection point; A target curve calculation module is used to calculate the target curvature and target curvature change rate of the projection curve containing each projection point based on each projection information; A lateral control module, which is used to obtain a basic feedforward compensation amount based on the target curvature when the current working condition is a straight-line driving condition, and perform lateral control in combination with the basic feedforward compensation amount; When the current operating condition is a curve, a straight-line entry into a curve, or a straight-line entry into a straight-line condition, after obtaining a basic feedforward compensation amount based on the target curvature, a compensation gain is obtained by looking up the target curvature and the target curvature change rate. Based on the target curvature change rate and the compensation gain, a secondary feedforward compensation amount is obtained, and lateral control is performed by combining the basic and secondary feedforward compensation amounts.

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