A method, device and equipment for cooperative control of a chassis-by-wire multi-actuator for vehicle parking assistance and a storage medium

Abstract

A kind of line control chassis multi-actuator cooperative control method, device, equipment and storage medium for vehicle parking assistance, comprising: according to the current actual state information of target vehicle chassis obtained and pre-set three-degree-of-freedom vehicle dynamics model, the state information of target vehicle chassis in prediction time domain is obtained;According to the reference trajectory obtained and the state information of target vehicle chassis in the prediction time domain, an optimization objective function is constructed;According to the pre-set solver obtained, the optimization objective function and pre-set constraint condition, the control sequence in each control cycle is obtained;The control sequence is broadcasted to line control chassis multi-actuator by vehicle-mounted Ethernet, to make the line control chassis multi-actuator control the line control steering unit, the line control brake unit and the line control driving unit execute the control sequence according to timestamp, solve the technical problem of three-actuator response delay difference in existing parking assistance system in the related art.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, specifically to a method, apparatus, device, and computer-readable storage medium for multi-actuator coordinated control of a drive-by-wire chassis for vehicle parking assistance. Background Technology

[0002] With the rapid development of intelligent technology in new energy vehicles, automatic parking assist systems have become an important component of intelligent driving systems. They effectively reduce the difficulty of manual parking operations and improve parking safety and convenience. Currently, most automatic parking assist systems for new energy vehicles in the industry adopt a hierarchical control architecture. The entire system hardware architecture is mature and complete, mainly comprising an environmental perception unit, an APA parking controller, and three major drive-by-wire chassis execution subsystems. The environmental perception unit consists of 8-12 ultrasonic radars and 4 surround-view cameras, which can collect information on the parking lot environment, parking space dimensions, and surrounding obstacles from all directions, providing data support for parking decisions.

[0003] The system's execution end is configured with three independent subsystems: steer-by-wire, brake-by-wire, and drive-by-wire. Each subsystem is equipped with an independent ECU (Electronic Control Unit), enabling individual control of each actuator. Compared to the traditional integrated architecture, the layered architecture achieves a layered layout of perception, decision-making, and execution functions, significantly optimizing the parking control logic. However, in actual vehicle applications and scenario testing, existing layered automatic parking assistance systems still have core technical deficiencies.

[0004] Due to inherent differences in the hardware response characteristics and control algorithm parameters of the three major actuator subsystems—steer-by-wire, brake-by-wire, and drive-by-wire—significant differences in execution response latency still occur, even when each system is equipped with an independent ECU. The inability to precisely match the timing of the actions of each actuator can cause problems such as deviations in vehicle parking path tracking and untimely attitude control. In scenarios such as narrow parking spaces or complex multi-vehicle parking, this can easily lead to parking trajectory deviations, vehicle scrapes, and parking termination failures, significantly impacting the accuracy and stability of automatic parking and failing to meet the safety and precision requirements of high-end intelligent parking. Therefore, a targeted solution is urgently needed to address the technical challenge of the response latency differences among the three actuators. Summary of the Invention

[0005] This application provides a method, apparatus, device, and computer-readable storage medium for multi-actuator cooperative control of a drive-by-wire chassis for vehicle parking assistance, which can solve the technical problem of the difference in response delay of the three actuators in existing parking assistance systems.

[0006] In a first aspect, embodiments of this application provide a drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance, including: Based on the current actual state information of the target vehicle chassis and the preset three-degree-of-freedom vehicle dynamics model, the state information of the target vehicle chassis in the prediction time domain is obtained. The preset three-degree-of-freedom vehicle dynamics model includes a model for characterizing the response time difference between the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit. Based on the obtained reference trajectory and the state information of the target vehicle chassis in the prediction time domain, an optimization objective function is constructed; Based on the obtained preset solver, the optimization objective function, and the preset constraints, the control sequence within each control cycle is obtained; The control sequence is synchronously broadcast to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit to execute the control sequence according to the timestamp. The control sequence includes steering angle, braking pressure and drive torque.

[0007] In conjunction with the first aspect, in one implementation, based on the acquired reference trajectory and the state information of the target vehicle chassis in the prediction time domain, a trajectory tracking error term function, a smoothing constraint cost function, and a dynamic conflict suppression function are generated to construct an optimization objective function, including: Based on the obtained reference trajectory, the state information of the target vehicle chassis in the prediction time domain, and the first preset penalty coefficient, a trajectory tracking error term function is constructed. The reference trajectory includes the expected abscissa, expected ordinate, expected yaw angle, expected vehicle speed, and expected acceleration. The state information of the target vehicle chassis in the prediction time domain includes the predicted lateral position, predicted longitudinal position, predicted yaw angle, predicted longitudinal speed, and predicted yaw rate. Based on the rate of change of steering control command, braking control command and drive control command in adjacent control cycles obtained in the prediction time domain and the preset smoothing weights, a smoothing constraint cost function is constructed. Based on the simultaneous action state information of the steering control command, the braking control command and the drive control command in the predicted time domain, a dynamic conflict suppression function is constructed. Based on the trajectory tracking error term function, smoothing constraint cost function, and dynamic conflict suppression function, an optimization objective function is constructed.

[0008] In conjunction with the first aspect, in one embodiment, the constraints include an upper limit for steering angular velocity, an upper limit for brake pressure change rate, an upper limit for longitudinal acceleration, an upper limit for steering wheel angular velocity, and an upper limit for longitudinal impact.

[0009] In conjunction with the first aspect, in one embodiment, after synchronously broadcasting the control sequence to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steering-by-wire unit, the braking-by-wire unit, and the drive-by-wire unit to execute the control sequence according to timestamps, the method further includes: The deviation is calculated based on the actual execution status information fed back by the multi-actuator of the drive-by-wire chassis via the vehicle Ethernet and the reference trajectory. Based on the deviation, construct the optimization objective function for the next cycle to achieve closed loop.

[0010] In conjunction with the first aspect, in one embodiment, after synchronously broadcasting the control sequence to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steering-by-wire unit, the braking-by-wire unit, and the drive-by-wire unit to execute the control sequence according to timestamps, the method further includes: The deviation is calculated based on the actual execution status information fed back by the multi-actuator of the drive-by-wire chassis via the vehicle Ethernet and the reference trajectory. If the deviation is greater than a preset deviation threshold and the duration is greater than a preset duration, an alarm message is triggered. The chassis coordination controller sends safety coordination commands to the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit. Based on the aforementioned safety coordination command, the braking pressure is controlled to a preset safe braking pressure, the steering angle remains unchanged, and the driving torque is forced to zero.

[0011] In conjunction with the first aspect, in one implementation, acquiring the reference trajectory includes: Obtain the global parking trajectory sequence of the target vehicle within the communication period; The global parking trajectory sequence is smoothed by fifth-order spline interpolation and resampled according to a preset sampling period to generate a reference trajectory with continuous curvature and the preset sampling period.

[0012] In conjunction with the first aspect, in one implementation, the step of obtaining the state information of the target vehicle chassis in the prediction time domain based on the acquired current actual state information of the target vehicle chassis and a preset three-degree-of-freedom vehicle dynamics model includes: Obtain the current actual state information of the target vehicle chassis, and substitute the current actual state information as the initial state information into the preset three-degree-of-freedom vehicle dynamics model. The current actual state information includes the actual vehicle speed, actual yaw angle, actual steering angle and actual wheel speed. Based on the pre-set three-degree-of-freedom vehicle dynamics model, first-order lag modeling is performed on the response delay parameters of the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit to obtain the state information of the target vehicle chassis in the prediction time domain.

[0013] Secondly, embodiments of this application provide a drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance, the drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance comprising: The first acquisition module is used to acquire the state information of the target vehicle chassis in the prediction time domain based on the current actual state information of the target vehicle chassis and the preset three-degree-of-freedom vehicle dynamics model. The preset three-degree-of-freedom vehicle dynamics model includes a model for characterizing the response time difference between the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit. The construction module is used to construct an optimization objective function based on the obtained reference trajectory and the state information of the target vehicle chassis in the prediction time domain; The second acquisition module is used to acquire the control sequence within each control cycle based on the acquired preset solver, the optimization objective function, and the preset constraints. The control module is used to synchronously broadcast the control sequence to the steer-by-wire chassis multi-actuator via an in-vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit to execute the control sequence according to a timestamp, the control sequence including steering angle, braking pressure and drive torque.

[0014] Thirdly, embodiments of this application provide a drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance. The drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance includes a processor, a memory, and a drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance stored in the memory and executable by the processor. When the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance is executed by the processor, it implements the steps of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described above.

[0015] Fourthly, embodiments of this application provide a computer-readable storage medium storing a drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance, wherein when the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance is executed by a processor, it implements the steps of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described above.

[0016] The beneficial effects of the technical solutions provided in this application include: By acquiring the current actual state information of the target vehicle chassis and a preset three-degree-of-freedom vehicle dynamics model, the state information of the target vehicle chassis in the prediction time domain is obtained. The preset three-degree-of-freedom vehicle dynamics model includes a method to characterize the response time difference between the steer-by-wire unit, brake-by-wire unit, and drive-by-wire unit. Based on the acquired reference trajectory and the state information of the target vehicle chassis in the prediction time domain, an optimization objective function is constructed. Based on the acquired preset solver, the optimization objective function, and preset constraints, a control sequence is obtained for each control cycle. The control sequence is synchronously broadcast to the steer-by-wire chassis multi-actuator via an in-vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, brake-by-wire unit, and drive-by-wire unit to execute the control sequence according to a timestamp. The control sequence includes steering angle, braking pressure, and drive torque, thus solving the technical problem of response delay differences among the three actuators in existing parking assistance systems. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the first embodiment of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance according to this application; Figure 2 This is a schematic diagram of the functional modules of an embodiment of the drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance according to this application; Figure 3 This is a schematic diagram of the hardware structure of a drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance, as described in the embodiments of this application. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0019] First, some of the technical terms used in this application will be explained to help those skilled in the art understand this application.

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0021] In a first aspect, embodiments of this application provide a drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance.

[0022] In one embodiment, reference is made to Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance according to this application. Figure 1 As shown, the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance includes: Step S10: Based on the current actual state information of the target vehicle chassis and the preset three-degree-of-freedom vehicle dynamics model, obtain the state information of the target vehicle chassis in the prediction time domain. The preset three-degree-of-freedom vehicle dynamics model includes a model for characterizing the response time difference between the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit. As an example, the current actual status information of the vehicle chassis is read, including the actual vehicle speed. Actual yaw angle Actual steering angle and actual wheel speed The internal prediction starting point is utilized by a pre-set three-degree-of-freedom vehicle dynamics model predictive controller (MPC). Based on the acquired current actual state information of the target vehicle chassis and the pre-set three-degree-of-freedom vehicle dynamics model, the state information of the target vehicle chassis in the prediction time domain is obtained. The current actual state of the target vehicle chassis includes the actual vehicle speed. Actual yaw angle Actual steering angle and actual wheel speed The predicted state information of the target vehicle chassis in the time domain includes the predicted lateral position y, the predicted longitudinal position x, the predicted yaw angle θ, and the predicted longitudinal velocity. And predict the yaw rate ω.

[0023] For example, obtaining the current actual state of the target vehicle chassis in its initial state includes the actual vehicle speed. Actual yaw angle Actual steering angle and actual wheel speed Actual vehicle speed The actual yaw angle is calculated from the wheel speed pulse. Actual steering angle as observed from the IMU The actual wheel speed is transmitted back from the steering ECU. From wheel speed sensors. MPC model rolling prediction (10ms per control cycle, 150 prediction steps = 1.5s), for the k-th step (k=1,2,...,150). Three-degree-of-freedom vehicle dynamics model (including delay compensation): x(k+1) = x(k) + v(k)·cos[θ(k)]·Δt; y(k+1) = y(k) + v(k)·sin[θ(k)]·Δt; θ(k+1)= θ(k) + ω(k)·Δt; v(k+1) = v(k) + a(k)·Δt; ω(k+1)= ω(k) + (yaw moment / I_z)·Δt. a(k) and yaw moment(k) are obtained by the optimization solver in the current cycle, and then substituted into the model prediction. Simultaneously apply delay compensation: steering command Delay The braking command takes effect after 12ms. Delay =It takes effect after 35ms, driver command Delay =It takes effect after 8ms. Output the predicted state sequence. [x(1), y(1), θ(1), v(1), ω(1)], [x(2), y(2), θ(2), v(2), ω(2)],..., [x(150), y(150), θ(150), v(150), ω(150)].

[0024] Step S20: Based on the obtained reference trajectory and the state information of the target vehicle chassis in the prediction time domain, construct an optimization objective function; As an example, the system acquires the global parking trajectory sequence of the target vehicle within a communication period; it then performs fifth-order spline interpolation smoothing on the global parking trajectory sequence and resamples it according to a preset sampling period to generate a reference trajectory with continuous curvature and a preset sampling period. The chassis cooperative controller obtains the global parking trajectory sequence from the APA planning module. Each trajectory point contains the desired pose and velocity information. If no updated trajectory sequence is received within a continuous 200ms communication cycle, a safety stop mode is triggered, and a braking command is output. The received trajectory sequence R is smoothed and resampled using fifth-order spline interpolation to generate an internal reference track with continuous curvature and a period of 10ms. Within each 10ms control cycle, a continuous reference trajectory will be generated. The deviation between the future vehicle state obtained from the predicted state information of the target vehicle chassis in the time domain and the actual future vehicle state is input into a centralized MPC optimization solver for unified solution, yielding the optimization objective function J. The optimization objective function J includes the trajectory tracking error term function. Smoothing constraint cost function and dynamic conflict suppression function .

[0025] For example, Model Predictive Control (MPC) is used as the objective cost function for trajectory tracking in autonomous vehicles. Its purpose is to quantify the total deviation between the vehicle's actual predicted state and the desired state along the reference trajectory within the prediction time domain. MPC minimizes this cost during the solution process, allowing the vehicle to follow the target trajectory and speed as closely as possible. The complete formula is as follows:

[0026] in, The prediction time domain length represents the controller's forward prediction of the future. The vehicle state for each control step; k: the time step index in the prediction time domain (k=1 is the next moment, k= (This is the furthest predicted time). , , , Weighting coefficient (penalty coefficient): Manually tuned to control the importance of different state deviations. The larger the weight, the more severely the state deviation is penalized, and the controller will prioritize eliminating this deviation.

[0027]

[0028] By squaring each item: the influence of the positive or negative sign of the deviation is eliminated (left / right deviation, fast / slow will all produce positive costs); the penalty effect of large deviations is amplified: the larger the deviation, the higher the cost will be, forcing the controller to avoid large deviations from the trajectory.

[0029] The control quantity smoothing cost term of predictive control (MPC) is related to the trajectory tracking cost. Together they form the complete overall objective function of MPC. Responsible for ensuring the car follows the reference trajectory, and It is specifically designed to prevent abrupt changes in the movements of the three major actuators: steering wheel, brakes, and drive system. Its core objectives are: to improve ride comfort and eliminate jerks and shocks; to suppress noise caused by sudden changes in the steering and braking systems; and to protect the vehicle's actuators from frequent and severe impacts that could damage the hardware.

[0030]

[0031] : Control time domain, representing the number of continuous control action steps planned by MPC in the future; The summation range is the difference between all two adjacent control steps, and it applies an overall cumulative penalty to the degree of mutation in the entire control sequence.

[0032] Weighting coefficient , , These are the smoothing weights for steering, braking, and drive torque, respectively. The greater the weight, the more the controller will try to suppress abrupt changes in the corresponding actuator's movement. For example, to achieve a smooth and comfortable ride, the weight is increased... , Pursuing a quiet turn, increasing... .

[0033] The squared term design squares the difference between adjacent control variables. Positive and negative changes (sudden increase / decrease in force) will generate positive costs. The larger the change, the greater the cost will be, thus forcing the algorithm to avoid drastic changes in action.

[0034]

[0035] Among them, Jerk, the rate of change of acceleration, is a core indicator for measuring ride comfort. Steering angular velocity (steering wheel rotation speed) is the difference between the two values, which is equivalent to steering angular acceleration and is used to constrain the steering speed from being too fast or too slow.

[0036] And a dynamic conflict suppression function specifically designed for parking scenarios. , where α P T specifically penalizes the internal friction condition where both braking and driving commands are positive simultaneously; the second term... This addresses the issue of noise during stationary turning caused by simultaneous large turning speeds and braking forces. A unified optimization objective function is constructed by weighted summation of the three factors mentioned above. .

[0037] Step S30: Based on the obtained preset solver, the optimization objective function, and the preset constraints, obtain the control sequence within each control cycle; As an example, with minimizing the constructed multi-objective function J as the optimization objective, constraints are imposed: Hard constraints are imposed on the optimization problem, including steering angular velocity ≤100° / s, braking pressure change rate ≤5MPa / s, longitudinal acceleration ≤±10m / s³, and the physical limits of each actuator (such as maximum braking pressure and maximum drive torque). This ensures that the solution does not exceed the actual capability range of the actuators. The upper limit of steering angular velocity constrains the front wheel steering angle change rate, and the upper limit of steering wheel steering angular velocity constrains the steering wheel angle change rate. These two are related through the steering transmission ratio but are independent constraints. The problem is transformed into a standard quadratic programming (QP) problem and solved online. The solver searches for the control sequence that optimizes the overall performance in each control cycle. Each control quantity The commands for steering angle, braking pressure, and drive torque are synchronized in time. This sequence is the optimal cooperative control sequence U in the prediction time domain, which can actively compensate for actuator delay differences and suppress action conflicts.

[0038] Step S40: The control sequence is synchronously broadcast to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit to execute the control sequence according to the timestamp. The control sequence includes steering angle, braking pressure and drive torque.

[0039] As an example, the chassis co-controller will use the timestamped control commands generated in step four. The command is synchronously broadcast to the three actuators—steer-by-wire, braking, and drive—via the vehicle's Ethernet network. Upon receiving the command, each actuator executes it simultaneously at the time specified by the timestamp, ensuring strict alignment of the action windows for steering angle, braking pressure, and drive torque, eliminating misalignment caused by communication delays. The timestamp is not arbitrarily set; it is precisely calculated based on a unified, fixed "heartbeat" cycle (Tc) and the current time (tnow) across the entire system. Source: Timestamp = Current Time + Number of Steps × Control Cycle; Purpose: To ensure that all actuators execute the actions planned for them by the controller at exactly the same future point in time, achieving perfect coordination. Essence: This is a time-triggered execution mechanism, the foundation for achieving high-precision, high-reliability vehicle control.

[0040] Specifically, after the step of synchronously broadcasting the control sequence to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steering-by-wire unit, the braking-by-wire unit, and the drive-by-wire unit to execute the control sequence according to the timestamp, the method further includes: calculating the deviation based on the actual execution status information fed back by the steer-by-wire chassis multi-actuator via the vehicle Ethernet and the reference trajectory; and constructing an optimization objective function for the next cycle based on the deviation to achieve closed loop.

[0041] As an example, after each execution unit completes its execution, it immediately transmits the actual execution status back to the chassis co-controller via the vehicle Ethernet. The feedback cycle is strictly synchronized with the command cycle at 10ms (100Hz). The specific feedback status data includes: actual feedback steering angle. Actual feedback braking pressure Actual feedback drive torque Vehicle speed calculated from feedback wheel speed pulses and the actual feedback yaw angle observed from the inertial measurement unit (IMU) After receiving the above feedback, the collaborative controller compares the actual state with the expected value of the internal reference trajectory at the current moment and calculates the deviation:

[0042] and The desired location (source path planning module) at the start of Automatic Parking (APA) plans a reference trajectory from the current location to the target parking space based on the parking space size and vehicle dimensions. This trajectory is a series of discrete points: (x0, y0), (x1, y1), (x2, y2),... For the current time t, the system directly reads the corresponding coordinates from this planned curve. and . , The system originates from the positioning and perception module, where the vehicle measures its own status in real time using onboard sensors. The most crucial sensors are GPS / RTK (Global Positioning System) and IMU (Inertial Measurement Unit, containing accelerometers and gyroscopes). Sometimes, wheel speed sensors (which calculate distance based on wheel rotations) or visual sensors (cameras identifying lane lines or parking spaces) are used to assist in corrections. The system uses sensor fusion algorithms (such as Kalman filtering) to process this raw data into precise real-time coordinates of the vehicle in the coordinate system. , At the same time, the local deviation between the actual execution amount and the instruction value will be considered. This is recorded as an actuator health status indicator. The deviation is used as the initial state correction and fed back to the next control cycle, replacing the original open-loop prediction starting point. Specifically, the MPC prediction model for the next cycle will use the actual vehicle state feedback. As a new initial state The system then re-optimizes based on the incomplete reference trajectory segments. This creates a closed loop between the system's control input and trajectory tracking error, providing real-time compensation for external disturbances and model mismatch.

[0043] Specifically, after the step of synchronously broadcasting the control sequence to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit to execute the control sequence according to the timestamp, the method further includes: calculating the deviation based on the actual execution status information fed back by the steer-by-wire chassis multi-actuator via the vehicle Ethernet and the reference trajectory; if the deviation is greater than a preset deviation threshold and the duration is greater than a preset duration, triggering an alarm message; sending a safety coordination command to the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit through the chassis coordination controller; and controlling the braking pressure to a preset safe braking pressure, keeping the steering angle unchanged, and forcing the drive torque to zero based on the safety coordination command.

[0044] As an example, after each execution unit completes its execution, it immediately transmits the actual execution status back to the chassis co-controller via the vehicle Ethernet. The feedback cycle is strictly synchronized with the command cycle at 10ms (100Hz). The specific feedback status data includes: actual steering angle. Actual braking pressure Actual driving torque Vehicle speed converted from wheel speed pulse and the actual yaw angle observed from the inertial measurement unit (IMU) After receiving the above feedback, the collaborative controller compares the actual state with the expected value of the internal reference trajectory at the current moment and calculates the deviation:

[0045] The xref and yref (desired positions) originate from the path planning module. At the start of Automatic Parking (APA), the system plans a reference trajectory from the current position to the target parking space based on the parking space size and vehicle dimensions. This trajectory is a series of discrete points: (x0, y0), (x1, y1), ..., (x2, y2)... For the current time t, the system directly reads the corresponding coordinates from this planned curve. and . , The system originates from the positioning and perception module, where the vehicle measures its own status in real time using onboard sensors. The most crucial sensors are GPS / RTK (Global Positioning System) and IMU (Inertial Measurement Unit, containing accelerometers and gyroscopes). Sometimes, wheel speed sensors (which calculate distance based on wheel rotations) or visual sensors (cameras identifying lane lines or parking spaces) are used to assist in corrections. The system uses sensor fusion algorithms (such as Kalman filtering) to process this raw data into precise real-time coordinates of the vehicle in the coordinate system. , At the same time, the local deviation between the actual execution amount and the instruction value will be considered. This is recorded as an actuator health status indicator. If the deviation of any actuator continuously exceeds a preset safety threshold (e.g., ...), ... The preset safety thresholds are set based on the physical characteristics of the actuator. For example, the brake pressure deviation threshold is set to 0.5MPa to 1.5MPa, and the drive torque deviation threshold is set to 10Nm to 30Nm. If this out-of-tolerance state is detected within five consecutive control cycles (i.e., 50ms), the actuator is determined to have a response abnormality. Fault-tolerant action execution: After an abnormality is triggered, the chassis cooperative controller immediately suspends the current normal MPC optimization solution process and forcibly issues a set of predefined safety cooperative instructions: brake pressure is locked at 3~5MPa (ensuring the vehicle stops as quickly as possible), the steering angle remains unchanged at the current actual steering angle, and the drive torque is forcibly set to zero. This safety instruction is also appended with a global timestamp and broadcast via the vehicle Ethernet, replacing the normal instruction in step four. Abnormal exit and alarm: While the above safety instructions are being executed, a parking abnormality abort signal and fault code are sent to the APA module and body control system through the vehicle gateway, prompting the driver to take over the vehicle.

[0046] In this embodiment, the target vehicle chassis's current actual state information and a preset three-degree-of-freedom vehicle dynamics model are used to obtain the target vehicle chassis's state information in the prediction time domain. The preset three-degree-of-freedom vehicle dynamics model includes parameters to characterize the response time differences between the steer-by-wire unit, brake-by-wire unit, and drive-by-wire unit. An optimization objective function is constructed based on the obtained reference trajectory and the target vehicle chassis's state information in the prediction time domain. A control sequence is obtained for each control cycle based on the obtained preset solver, the optimization objective function, and preset constraints. The control sequence is synchronously broadcast to the steer-by-wire chassis multi-actuator via an in-vehicle Ethernet network, enabling the steer-by-wire chassis multi-actuator to control the steer-by-wire unit, brake-by-wire unit, and drive-by-wire unit to execute the control sequence according to a timestamp. The control sequence includes steering angle, braking pressure, and drive torque, thus solving the technical problem of response delay differences among the three actuators in existing parking assistance systems.

[0047] Secondly, embodiments of this application also provide a drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance.

[0048] In one embodiment, reference is made to Figure 2 , Figure 2 This is a functional module diagram of an embodiment of the drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance, as described in this application. Figure 2 As shown, the drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance includes: The first acquisition module 10 is used to acquire the state information of the target vehicle chassis in the prediction time domain based on the current actual state information of the target vehicle chassis and the preset three-degree-of-freedom vehicle dynamics model. The preset three-degree-of-freedom vehicle dynamics model includes a model for characterizing the response time difference between the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit. Construction module 20 is used to construct an optimization objective function based on the acquired reference trajectory and the state information of the target vehicle chassis in the prediction time domain; The second acquisition module 30 is used to acquire the control sequence in each control cycle based on the acquired preset solver, the optimization objective function and the preset constraints. The control module 40 is used to synchronously broadcast the control sequence to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit to execute the control sequence according to the timestamp, the control sequence including steering angle, braking pressure and drive torque.

[0049] Furthermore, in one embodiment, the construction module 20 is used for: Based on the obtained reference trajectory, the state information of the target vehicle chassis in the prediction time domain, and the first preset penalty coefficient, a trajectory tracking error term function is constructed. The reference trajectory includes the expected abscissa, expected ordinate, expected yaw angle, expected vehicle speed, and expected acceleration. The state information of the target vehicle chassis in the prediction time domain includes the predicted lateral position, predicted longitudinal position, predicted yaw angle, predicted longitudinal speed, and predicted yaw rate. Based on the rate of change of steering control command, braking control command and drive control command in adjacent control cycles obtained in the prediction time domain and the preset smoothing weights, a smoothing constraint cost function is constructed. Based on the simultaneous action state information of the steering control command, the braking control command and the drive control command in the predicted time domain, a dynamic conflict suppression function is constructed. Based on the trajectory tracking error term function, smoothing constraint cost function, and dynamic conflict suppression function, an optimization objective function is constructed.

[0050] Furthermore, in one embodiment, the constraints include an upper limit for steering angular velocity, an upper limit for brake pressure change rate, an upper limit for longitudinal acceleration, an upper limit for steering wheel angular velocity, and an upper limit for longitudinal impact.

[0051] Furthermore, in one embodiment, the drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance further includes a new module for: The deviation is calculated based on the actual execution status information fed back by the multi-actuator of the drive-by-wire chassis via the vehicle Ethernet and the reference trajectory. Based on the deviation, construct the optimization objective function for the next cycle to achieve closed loop.

[0052] Furthermore, in one embodiment, the drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance further includes a new module for: The deviation is calculated based on the actual execution status information fed back by the multi-actuator of the drive-by-wire chassis via the vehicle Ethernet and the reference trajectory. If the deviation is greater than a preset deviation threshold and the duration is greater than a preset duration, an alarm message is triggered. The chassis coordination controller sends safety coordination commands to the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit. Based on the aforementioned safety coordination command, the braking pressure is controlled to a preset safe braking pressure, the steering angle remains unchanged, and the driving torque is forced to zero.

[0053] Further, in one embodiment, obtaining the reference trajectory includes: Obtain the global parking trajectory sequence of the target vehicle within the communication period; The global parking trajectory sequence is smoothed by fifth-order spline interpolation and resampled according to a preset sampling period to generate a reference trajectory with continuous curvature and the preset sampling period.

[0054] Furthermore, in one embodiment, the first acquisition module 10 is used to: Obtain the current actual state information of the target vehicle chassis, and substitute the current actual state information as the initial state information into the preset three-degree-of-freedom vehicle dynamics model. The current actual state information includes the actual vehicle speed, actual yaw angle, actual steering angle and actual wheel speed. Based on the pre-set three-degree-of-freedom vehicle dynamics model, first-order lag modeling is performed on the response delay parameters of the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit to obtain the state information of the target vehicle chassis in the prediction time domain.

[0055] The functions of each module in the above-mentioned drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance correspond to the steps in the above-mentioned drive-by-wire chassis multi-actuator collaborative control method embodiment for vehicle parking assistance. Their functions and implementation processes will not be described in detail here.

[0056] Thirdly, embodiments of this application provide a drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance. The drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance can be a personal computer (PC), laptop computer, server, or other device with data processing capabilities.

[0057] Reference Figure 3 , Figure 3 This is a schematic diagram of the hardware structure of a drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance, as described in an embodiment of this application. In this embodiment, the drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance may include a processor, a memory, a communication interface, and a communication bus.

[0058] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0059] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces. These interfaces enable interconnection of devices within the drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance, and also enable interconnection between the drive-by-wire chassis multi-actuator collaborative control device and other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0060] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0061] The processor can be a general-purpose processor, which can call the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance stored in memory and execute the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance is called can be referred to in the various embodiments of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance in this application, and will not be repeated here.

[0062] Those skilled in the art will understand that Figure 3 The hardware structure shown does not constitute a limitation of this application and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0063] Fourthly, embodiments of this application also provide a computer-readable storage medium.

[0064] The present application stores a drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance on a computer-readable storage medium, wherein when the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance is executed by a processor, the steps of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described above are implemented.

[0065] The method implemented when the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance is executed can be referred to in the various embodiments of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance in this application, and will not be repeated here.

[0066] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0067] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0068] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0069] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0070] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0071] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. 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 this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0072] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for coordinated control of multiple actuators in a drive-by-wire chassis for vehicle parking assistance, characterized in that, include: Based on the current actual state information of the target vehicle chassis and the preset three-degree-of-freedom vehicle dynamics model, the state information of the target vehicle chassis in the prediction time domain is obtained. The preset three-degree-of-freedom vehicle dynamics model includes a model for characterizing the response time difference between the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit. Based on the obtained reference trajectory and the state information of the target vehicle chassis in the prediction time domain, an optimization objective function is constructed. The optimization objective function includes a trajectory tracking error term function, a smoothing constraint cost function, and a dynamic conflict suppression function. Based on the obtained preset solver, the optimization objective function, and the preset constraints, the control sequence within each control cycle is obtained; The control sequence is synchronously broadcast to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit to execute the control sequence according to the timestamp. The control sequence includes steering angle, braking pressure and drive torque.

2. The drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in claim 1, characterized in that, The step of constructing an optimization objective function based on the obtained reference trajectory and the state information of the target vehicle chassis in the prediction time domain includes: Based on the obtained reference trajectory, the state information of the target vehicle chassis in the prediction time domain, and the first preset penalty coefficient, a trajectory tracking error term function is constructed. The reference trajectory includes the expected abscissa, expected ordinate, expected yaw angle, expected vehicle speed, and expected acceleration. The state information of the target vehicle chassis in the prediction time domain includes the predicted lateral position, predicted longitudinal position, predicted yaw angle, predicted longitudinal speed, and predicted yaw rate. Based on the rate of change of steering control command, braking control command and drive control command in adjacent control cycles obtained in the prediction time domain and the preset smoothing weights, a smoothing constraint cost function is constructed. Based on the simultaneous action state information of the steering control command, the braking control command and the drive control command in the predicted time domain, a dynamic conflict suppression function is constructed. Based on the trajectory tracking error term function, smoothing constraint cost function, and dynamic conflict suppression function, an optimization objective function is constructed.

3. The drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in claim 1, characterized in that, The constraints include upper limits for steering angular velocity, braking pressure change rate, longitudinal acceleration, steering wheel angular velocity, and longitudinal impact.

4. The drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in claim 1, characterized in that, After the step of synchronously broadcasting the control sequence to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit to execute the control sequence according to the timestamp, the method further includes: The deviation is calculated based on the actual execution status information fed back by the multi-actuator of the drive-by-wire chassis via the vehicle Ethernet and the reference trajectory. Based on the deviation, construct the optimization objective function for the next cycle to achieve closed loop.

5. The drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in claim 1, characterized in that, After the step of synchronously broadcasting the control sequence to the steer-by-wire chassis multi-actuator via the vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit to execute the control sequence according to the timestamp, the method further includes: The deviation is calculated based on the actual execution status information fed back by the multi-actuator of the drive-by-wire chassis via the vehicle Ethernet and the reference trajectory. If the deviation is greater than a preset deviation threshold and the duration is greater than a preset duration, an alarm message is triggered. The chassis coordination controller sends safety coordination commands to the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit. Based on the aforementioned safety coordination command, the braking pressure is controlled to a preset safe braking pressure, the steering angle remains unchanged, and the driving torque is forced to zero.

6. The drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in claim 1, characterized in that, The acquisition of the reference trajectory includes: Obtain the global parking trajectory sequence of the target vehicle within the communication period; The global parking trajectory sequence is smoothed by fifth-order spline interpolation and resampled according to a preset sampling period to generate a reference trajectory with continuous curvature.

7. The drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in claim 1, characterized in that, The step of obtaining the target vehicle chassis state information in the prediction time domain based on the current actual state information of the target vehicle chassis and the preset three-degree-of-freedom vehicle dynamics model includes: Obtain the current actual state information of the target vehicle chassis, and substitute the current actual state information as the initial state information into the preset three-degree-of-freedom vehicle dynamics model. The current actual state information includes the actual vehicle speed, actual yaw angle, actual steering angle and actual wheel speed. Based on the pre-set three-degree-of-freedom vehicle dynamics model, first-order lag modeling is performed on the response delay parameters of the steer-by-wire unit, the brake-by-wire unit, and the drive-by-wire unit to obtain the state information of the target vehicle chassis in the prediction time domain.

8. A drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance, characterized in that, The drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance includes: The first acquisition module is used to acquire the state information of the target vehicle chassis in the prediction time domain based on the current actual state information of the target vehicle chassis and the preset three-degree-of-freedom vehicle dynamics model. The preset three-degree-of-freedom vehicle dynamics model includes a model for characterizing the response time difference between the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit. The construction module is used to construct an optimization objective function based on the obtained reference trajectory and the state information of the target vehicle chassis in the prediction time domain; The second acquisition module is used to acquire the control sequence within each control cycle based on the acquired preset solver, the optimization objective function, and the preset constraints. The control module is used to synchronously broadcast the control sequence to the steer-by-wire chassis multi-actuator via an in-vehicle Ethernet, so that the steer-by-wire chassis multi-actuator controls the steer-by-wire unit, the brake-by-wire unit and the drive-by-wire unit to execute the control sequence according to a timestamp, the control sequence including steering angle, braking pressure and drive torque.

9. A drive-by-wire chassis multi-actuator collaborative control device for vehicle parking assistance, characterized in that, The drive-by-wire chassis multi-actuator cooperative control device for vehicle parking assistance includes a processor, a memory, and a drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance stored in the memory and executable by the processor. When the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance is executed by the processor, it implements the steps of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance, wherein when the drive-by-wire chassis multi-actuator cooperative control program for vehicle parking assistance is executed by a processor, it implements the steps of the drive-by-wire chassis multi-actuator cooperative control method for vehicle parking assistance as described in any one of claims 1 to 7.

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