This application relates to the field of automotive control technologies, and in particular, to a vehicle status parameter estimation method and apparatus.
In recent years, with development of intelligent automobiles, vehicle control systems including an electronic stability program (ESP), an antilock brake system (ABS), and a traction control system (TCS) have been more widely used in vehicles. Currently, to implement automatic control on the vehicles, various types of vehicle status data usually need to be collected to invoke the various vehicle control systems. Generally, various sensors may be installed on the vehicles, to collect the vehicle status data. However, some vehicle status data including a centroid sideslip angle usually needs to be measured by installing additional expensive sensors. Considering that manufacturing costs of mass production vehicles need to be controlled, people increasingly tend to obtain, through estimation by using signals collected by existing vehicle-mounted sensors on the vehicles, other parameters used for vehicle control, such as a centroid sideslip angle, a yaw angular velocity, and a longitudinal vehicle speed. However, a vehicle status parameter estimation method proposed in a current conventional technology has relatively low precision, and cannot satisfy a high-precision requirement for vehicle control.
This application provides a vehicle status parameter estimation method and a vehicle status parameter estimation apparatus, to improve estimation precision of a vehicle status parameter.
According to a first aspect, this application provides a vehicle status parameter estimation method. The method includes:
In this application, in a process of estimating the vehicle status parameter, the process covariance and the measurement covariance are adaptively adjusted based on the driving status data, and then an adjusted process covariance and measurement covariance are used for a vehicle status estimation, so that estimation precision of the vehicle status parameter can be improved.
In a possible implementation, the driving status data includes one or more of the following: a lateral acceleration change rate {dot over (r)}V, a steering wheel speed {dot over (δ)}, a horizontal acceleration ay, a road adhesion coefficient μ, a front left wheel speed ωFR, a front right wheel speed ωFR, a rear left wheel speed ωRL, or a rear right wheel speed ωRR.
In a possible implementation, the determining a second process covariance Q(k) based on the driving status data of the vehicle includes:
In a possible implementation, the determining a first measurement covariance R(k) based on the driving status data of the vehicle includes:
In a possible implementation, the determining the first measurement covariance R(k) based on the road adhesion coefficient μ includes:
In a possible implementation, the first measurement value yh of the vehicle sensor includes a measurement value measured by a real vehicle sensor and a measurement value obtained based on a virtual vehicle sensor, and the measurement value of the virtual vehicle sensor is obtained by using a neural network.
In this application, a result obtained by introducing another estimation method (for example, a kinematics-based status estimation, a neural network-based status estimation, and a vision-based status estimation) is used as the measurement value of the “virtual sensor”, the measurement value obtained through measurement of the real sensor and the calculated measurement covariance are extended, and the extended measurement value and measurement covariance are used for the vehicle status estimation. This can further improve the estimation precision of the vehicle status parameter.
In a possible implementation, the first process status x includes one or more of the following:
In a possible implementation, the first measurement value yh includes one or more of the following:
In a possible implementation, the vehicle status parameter includes one or more of the following:
According to a second aspect, this application provides a vehicle status parameter estimation apparatus. The apparatus includes:
The transceiver unit is configured to obtain a first measurement value yh of a vehicle sensor.
The processing unit is configured to determine a vehicle status parameter of the vehicle based on the first measurement value yh, the first process status x, the first process covariance Q, the second process covariance Q(k), and the first measurement covariance R(k).
In a possible implementation, the driving status data includes one or more of the following: a lateral acceleration change rate {dot over (r)}V, a steering wheel speed {dot over (δ)}, a horizontal acceleration ay, a road adhesion coefficient μ, a front left wheel speed ωFR, a front right wheel speed ωFR, a rear left wheel speed ωRL, or a rear right wheel speed ωRR.
In a possible implementation, the processing unit is configured to:
In a possible implementation, the processing unit is configured to:
In a possible implementation, the processing unit is configured to:
In a possible implementation, the first measurement value yh of the vehicle sensor includes a measurement value measured by a real vehicle sensor and a measurement value obtained based on a virtual vehicle sensor, and the measurement value of the virtual vehicle sensor is obtained by using a neural network.
In a possible implementation, the first process status x includes one or more of the following:
In a possible implementation, the first measurement value yh includes one or more of the following:
In a possible implementation, the vehicle status parameter includes one or more of the following:
According to a third aspect, this application provides a vehicle status parameter estimation apparatus. The apparatus may be a terminal device, an apparatus in a terminal device, or an apparatus that can work together with a terminal device. Alternatively, the vehicle status parameter estimation apparatus may be a chip system. The vehicle status parameter estimation apparatus may perform the method described in the first aspect. A function of the vehicle status parameter estimation apparatus may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or the software includes one or more units or modules corresponding to the foregoing function. The unit or module may be software and/or hardware. For operations performed by the vehicle status parameter estimation apparatus and beneficial effects, refer to the method and beneficial effects in the first aspect. Details are not described again.
According to a fourth aspect, this application provides a vehicle status parameter estimation apparatus. The apparatus may be a terminal device. The vehicle status parameter estimation apparatus includes a processor and a transceiver. The processor and the transceiver are configured to execute a computer program or instructions stored in at least one memory, to enable the apparatus to perform the method according to any implementation of the first aspect.
According to a fifth aspect, this application provides a vehicle status parameter estimation apparatus. The apparatus may be a terminal device, and the vehicle status parameter estimation apparatus includes a processor, a transceiver, and a memory. The processor, the transceiver, and the memory are coupled. The processor and the transceiver are configured to perform the method according to any implementation of the first aspect.
According to a sixth aspect, this application provides a computer-readable storage medium, where the storage medium stores a computer program or instructions, and when the computer program or the instructions are executed by a computer, the method according to any implementation of the first aspect is performed.
According to a seventh aspect, this application provides a computer program product including instructions. The computer program product includes computer program code, and when the computer program code is run on a computer, the method according to any implementation of the first aspect is performed.
According to an eighth aspect, a chip system is provided. The chip system includes a processor, and may further include a memory, and is configured to perform the method according to any aspect and any possible design of the first aspect. The chip system may include a chip, or include a chip and another discrete device.
The following clearly describes the technical solutions in embodiments of this application with reference to the accompanying drawings in embodiments of this application.
In descriptions of this application, unless otherwise specified, “/” means “or”. For example, A/B may indicate A or B. The term “and/or” in embodiments of this application describes only an association relationship for describing associated objects and represents that three relationships may exist. For example, A and/or B may represent the following three cases: Only A exists, both A and B exist, and only B exists. In addition, “at least one” means one or more, and “a plurality of” means two or more. The terms such as “first” and “second” do not limit a quantity and an execution sequence, and the terms such as “first” and “second” do not indicate a definite difference.
In this application, the term “example” or “for example” is used to represent giving an example, an illustration, or a description. Any embodiment or design scheme described as an “example” or “for example” in this application should not be explained as being more preferred or having more advantages than another embodiment or design scheme. To be precise, the word such as “example” or “for example” is intended to present a related concept in a specific manner.
For ease of understanding, the following first explains some terms in embodiments of this application.
1. Unscented Kalman filter (UKF): The UKF is another idea of resolving a nonlinear Kalman filter, where unscented transformation is used to resolve a problem of nonlinear transformation of probability distribution. The unscented Kalman filter does not need to calculate a Jacobian matrix like an extended Kalman filter, and can obtain a more accurate nonlinear processing effect when a calculation amount is roughly the same.
2. Inertial measurement unit (IMU): The IMU is an apparatus for measuring a three-axis attitude angle and an acceleration of an object, and usually includes three single-axis accelerometers and three single-axis gyroscopes.
3. Steering angle sensor (SAS): The SAS is used to measure a rotation angle of a steering wheel during vehicle steering, and mainly installed in a steering wheel column under the steering wheel.
4. Wheel speed sensor (WSS): The WSS is a sensor used to measure a speed of an automotive wheel. A commonly used wheel speed sensor mainly includes a magnetoelectric wheel speed sensor and a Hall wheel speed sensor.
5. Master cylinder pressure sensor (MPS): The MPS is a sensor used to measure a pressure in a master cylinder.
6. Advanced driver assistance system (ADAS): In a vehicle driving process, various sensors (a millimeter wave radar, a lidar, a camera, and a satellite navigator) mounted in a vehicle are used to sense an ambient environment at any time, collect data, identify, detect and track static and dynamic objects, and perform systematic calculation and analysis based on navigation map data, so that a driver can detect possible danger in advance, and comfort and safety of automotive driving are effectively improved.
The following describes a system architecture and a service scenario in embodiments of this application. It should be noted that the system architecture and the service scenario described in this application are intended to describe the technical solutions in this application more clearly, and do not constitute a limitation on the technical solutions provided in this application. Persons of ordinary skill in the art may know that with evolution of the system architecture and emergence of new service scenarios, the technical solutions provided in this application are also applicable to similar technical problems.
It should be noted that a high-precision vehicle status parameter estimation (briefly referred to as a vehicle status estimation) is an important prerequisite for vehicle dynamics control and autonomous driving motion control. With popularization of the ADAS and artificial intelligence (AI) technologies, sensors such as a vision sensor, an inertial navigation sensor, a radar, a lidar, and the like are more used in the vehicle. Therefore, new opportunities are provided for the vehicle status estimation. An increasing quantity of sensors can usually reduce a quantity of vehicle status estimations, such as a centroid sideslip angle estimation, and a road adhesion coefficient estimation. For example,
For example,
The following further describes a vehicle status parameter estimation system provided in embodiments of this application.
For example,
The (2) driving status adaptation module obtains motion status information (for example, an acceleration, a yaw angular velocity, a wheel speed, a steering wheel angle, a driving torque, and a braking torque) of the vehicle, related environment information (for example, a road adhesion coefficient), and the like to analyze a driving status characteristic, and determines an adaptive strategy of a process covariance and a measurement covariance based on an analysis result of the driving status characteristic, that is, performs adaptive adjustment on the process covariance and the measurement covariance. This module can resolve dependence of a UKF on dynamic model precision, and improve estimation precision and fusion precision of the dynamic UKF.
The (3) UKF vehicle status estimation module uses an unscented Kalman filter method to comprehensively estimate a vehicle status, for example, a vehicle speed, a centroid sideslip angle, a tire force, a slip ratio, a tire sideslip angle. This module mainly includes the following five sub-modules: a sigma points generation sub-module, a sigma points unscented transformation sub-module, a prior estimation sub-module, a posterior estimation sub-module, and an output model sub-module. For functions of the five sub-modules, refer to description of steps in a process shown in
S401: Obtain driving status data of a vehicle, a first process status x, and a first process covariance Q.
In some feasible implementations, if a vehicle status parameter needs to be estimated, the driving status data of the vehicle, the first process status x, and the first process covariance Q may be first obtained. The driving status data of the vehicle may include environment information and motion status information of the vehicle during vehicle running. For example, the environment information may include a road adhesion coefficient μ, and the like, and the motion status information of the vehicle may include an acceleration (for example, a horizontal acceleration ay and a longitudinal acceleration ax), a yaw angular velocity r, a wheel speed (for example, a front left wheel speed ωFL, a front right wheel speed ωFR, a rear left wheel speed ωRL, and a rear right wheel speed ωRR of the vehicle), a steering wheel speed {dot over (δ)}, a driving torque, a braking torque, and the like. This is not limited herein. It should be noted that, in this embodiment of this application, a derivative of the yaw angular velocity r is equal to a yaw angular acceleration. For ease of description, the yaw angular acceleration may be denoted as {dot over (r)}. A derivative of a steering wheel angle δ obtained through SAS measurement is equal to the steering wheel speed. For ease of description, the steering wheel speed may be denoted as {dot over (δ)}. A product of the yaw angular acceleration {dot over (r)} and a longitudinal speed vx is equal to a lateral acceleration change rate. For ease of description, the lateral acceleration change rate in this application may be denoted as {dot over (r)}V. V=vx. Therefore, the driving status data in this embodiment of this application may include one or more of the following parameters: the lateral acceleration change rate {dot over (r)}V, the steering wheel speed {dot over (δ)}, the horizontal acceleration ay, the road adhesion coefficient μ, the front left wheel speed ωFR, the front right wheel speed ωFR, the rear left wheel speed ωRL, or the rear right wheel speed ωRR.
The first process status x may include one or more of the following parameters: the longitudinal speed vx, a horizontal speed vy, the yaw angular velocity r, the front left wheel speed ωFL, the front right wheel speed ωFR, the rear left wheel speed ωRL, the rear right wheel speed ωRR, or the road adhesion coefficient μ. This is not limited herein. In other words, the first process status in this embodiment of this application may be defined as the following matrix x.
Correspondingly, the first process covariance Q(k) may be defined as a diagonal matrix Q1. Q1=diag ([qv
Herein, qv
S402: Determine a second process covariance Q(k) and a first measurement covariance R(k) based on the driving status data of the vehicle.
In some feasible implementations, the second process covariance Q(k) and the first measurement covariance R(k) are determined based on the driving status data of the vehicle. Specifically, the determining the second process covariance Q(k) based on the driving status data of the vehicle may be understood as: when the road adhesion coefficient μ is greater than or equal to a first preset road adhesion coefficient threshold μTH, and an absolute value |{dot over (r)}V| of the lateral acceleration change rate is greater than a preset lateral acceleration change rate threshold {dot over (r)}VTH and/or an absolute value |{dot over (δ)}| of the steering wheel speed is greater than a preset steering wheel speed threshold {dot over (δ)}TH, obtaining a first preset process covariance matrix as the second process covariance Q(k); or when the road adhesion coefficient μ is greater than or equal to the first preset road adhesion coefficient threshold μTH, and the absolute value |{dot over (r)}V| of the lateral acceleration change rate is less than or equal to the preset lateral acceleration change rate threshold {dot over (r)}VTH and the absolute value |{dot over (δ)}| of the steering wheel speed is less than or equal to the preset steering wheel speed threshold {dot over (δ)}TH, determining the second process covariance Q(k) based on the horizontal acceleration ay; or when the road adhesion coefficient μ is less than the first preset road adhesion coefficient threshold μTH, and the absolute value |{dot over (r)}V| of the lateral acceleration change rate is greater than the preset lateral acceleration change rate threshold {dot over (r)}VTH and/or the absolute value |{dot over (δ)}| of the steering wheel speed is greater than the preset steering wheel speed threshold {dot over (δ)}TH, obtaining a second preset process covariance matrix as the second process covariance Q(k); or when the road adhesion coefficient μ is less than the first preset road adhesion coefficient threshold μTH, and the absolute value |{dot over (r)}V| of the lateral acceleration change rate is less than or equal to the preset lateral acceleration change rate threshold {dot over (r)}VTH and the absolute value |{dot over (δ)}| of the steering wheel speed is less than or equal to the preset steering wheel speed threshold {dot over (δ)}TH, obtaining a third preset process covariance matrix as the second process covariance Q(k).
For example,
As shown in
It should be noted that qμ values in state0 to state7 in
In some feasible implementations, the determining a first measurement covariance R(k) based on the driving status data of the vehicle may be understood as: when a maximum value max|Δωi| of absolute values of wheel speeds of different wheels is greater than a preset wheel speed difference threshold ΔωTH, and/or a minimum value min|ωi| of absolute values of wheel speeds of different wheels is less than a preset wheel speed threshold ωTH, obtaining a first preset measurement covariance matrix as the first measurement covariance R(k); or when the maximum value max|Δωi| of the absolute value of the wheel speed difference between the different wheels is less than or equal to the preset wheel speed difference threshold ΔωTH, and the minimum value min|ωi| of the absolute values of the wheel speeds of the different wheels is greater than or equal to the preset wheel speed threshold ωTH, determine the first measurement covariance R(k) based on the road adhesion coefficient μ. The determining the first measurement covariance R(k) based on the road adhesion coefficient μ may be understood as: when the road adhesion coefficient μ is greater than or equal to a second preset road adhesion coefficient threshold μ′TH, obtain a second preset measurement covariance matrix as the first measurement covariance R(k); or when the road adhesion coefficient μ is less than the second preset road adhesion coefficient threshold μ′TH, obtaining a third preset measurement covariance matrix as the first measurement covariance R(k).
In one implementation, the first measurement covariance R(k) may be defined as a diagonal matrix R1. R1=diag ([ra
ra
Optionally, the first measurement covariance R(k) may alternatively be defined as a diagonal matrix R2. R2=diag ([ra
ra
For example,
S403: Obtain a first measurement value yh of a vehicle sensor.
In some feasible implementations, the first measurement value yh of the vehicle sensor is obtained. The first measurement value yh of the vehicle sensor may include a measurement value measured by a real vehicle sensor. For example, the first measurement value yh may include the longitudinal acceleration ax, the horizontal acceleration ay, and the yaw angular velocity r that are obtained through IMU measurement, the front left wheel speed ωFL, the front right wheel speed ωFR, the rear left wheel speed ωRL, the rear right wheel speed ωRR, and the like that are obtained through WSS measurement. This is not limited herein. In other words, yh=[ax, ay, r, ωFR, ωFR, ωRL, ωRR]. Correspondingly, the first measured covariance R(k)=diag ([ra
Optionally, the first measurement value yh may alternatively include a measurement value measured by a real vehicle sensor and a measurement value obtained based on a virtual vehicle sensor. The measurement value of the vehicle virtual sensor may include a measurement value obtained through neural network-based estimation, and/or a measurement value obtained through kinematics-based status estimation, and/or a measurement value obtained through vision-based status estimation. This is not limited herein. For example, a vehicle centroid sideslip angle βKinematic is obtained through kinematics-based status estimation, a vehicle centroid sideslip angle βNN is obtained through neural network-based status estimation, and a vehicle centroid sideslip angle βCamera is obtained through vision-based status estimation. Therefore, the first measurement value yh=[ax, ay, r, ωFR, ωFR, ωRL, ωRR, βKinematic, βNN, βCamera]. Correspondingly, the first measurement covariance R(k)=diag ([ra
It should be noted that, in this application, the measurement value and the measured covariance of the real vehicle sensor are extended, that is, in addition to the measurement value measured by the real vehicle sensor, the first measurement value yh further includes the measurement value obtained based on the virtual vehicle sensor. Correspondingly, in addition to the measurement covariance coefficient corresponding to the measurement value of the real vehicle sensor, the first measurement covariance further includes the measurement covariance coefficient corresponding to the measurement value of the virtual vehicle sensor. This can improve estimation precision of the vehicle status parameter.
S404: Determine a vehicle status parameter of the vehicle based on the first measurement value yh, the first process status x, the first process covariance Q, the second process covariance Q(k), and the first measurement covariance R(k).
In some feasible implementations, a vehicle status parameter of the vehicle is determined based on the first measurement value yh, the first process status x, the first process covariance Q, the second process covariance Q(k), and the first measurement covariance R(k). Specifically, the determining a vehicle status parameter of the vehicle based on the first measurement value yh, the first process status x, the first process covariance Q, the second process covariance Q(k), and the first measurement covariance R(k) may be understood as: determining first key point data χi(k+1|k) and a second measurement value γi(k) based on the first process status x and the first process covariance Q, where both the first key point data χi(k+1|k) and the second measurement value γi(k) satisfy Gaussian distribution; and determining the vehicle status parameter of the vehicle based on the first key point data χi(k+1|k), the second measurement value γi(k), the second process covariance Q(k), the first measurement covariance R(k), and the first measurement value yh. The determining the vehicle status parameter of the vehicle based on the first key point data χi(k+1|k), the second measurement value γi(k), the second process covariance Q(k), the first measurement covariance R(k), the first measurement value yh, and a control variable status u(k) may be understood as: determining a prior process status {circumflex over (x)}(k+1|k) and a prior process covariance {circumflex over (P)}(k+1|k) based on the first key point data χi(k+1|k) and the second process covariance Q(k); determining a measurement estimated value ŷh(k) and a measurement estimated covariance {circumflex over (P)}y(k) based on the second measurement value γi(k) and the first measurement covariance R(k); determining a Kalman feedback gain matrix K(k+1|k) based on the first key point data χi(k+1|k), the second measurement value γi(k), the prior process status {circumflex over (x)}(k+1|k), the measurement estimated value ŷh(k) and the measurement estimated covariance {circumflex over (P)}y(k); determining a posterior process status {circumflex over (x)}(k+1) and a posterior process covariance {circumflex over (P)}(k+1) based on the Kalman feedback gain matrix K(k+1|k), the prior process covariance {circumflex over (P)}(k+1|k), the measurement estimated covariance {circumflex over (P)}y(k), the prior process status {circumflex over (x)}(k+1|k), the measurement estimated value ŷh(k), and the first measurement value yh(k); and determining the vehicle status parameter of the vehicle based on the posterior process status {circumflex over (x)}(k+1).
For example,
S701: Generate sigma points based on a first process status and a first process covariance.
In an implementation, a first process status x and a first process covariance Q at a moment k are obtained, and then the sigma points may be generated based on the first process status x and the first process covariance Q. Specifically, the sigma points χi(k) at the moment k may be generated based on a sampling value {circumflex over (x)}(k) of the first process status x at the moment k and a sampling value {circumflex over (P)}(k) of the first process covariance Q at the moment k. The generated sigma points χi(k) satisfy:
χi(k) represents sigma points at the moment k. {circumflex over (x)}(k) represents the sampling value of the first process status x at the moment k. {circumflex over (P)}(k) represents the sampling value of the first process covariance Q at the moment k. n represents a dimension (for example, n=8) of the first process status x. λ represents a preset coefficient used to calculate a weight. It should be noted that the sigma points are a series of representative points extracted from original Gaussian distribution (namely, Gaussian distribution based on an average value of the first process status and the first process covariance), are distributed around the average value of the first process status and represent the entire Gaussian distribution. More points extracted from the original Gaussian distribution usually indicate that a UKF approximates a nonlinear model more accurately.
S702: Perform unscented transformation on the generated sigma points, to obtain first key point data and a second measurement value.
In an implementation, the first key point data χi(k+1|k) and the second measurement value γi(k) may be obtained by performing unscented transformation on the generated sigma points. Specifically, unscented transformation may be separately performed on the generated sigma points χi(k) based on a seven-degree of freedom (DOF) nonlinear vehicle dynamics model and a measurement model, to obtain new sigma points, namely, the first key point data χi(k+1|k), at a moment k+1 obtained through prediction at the moment k and obtain the second measurement value γi(k) based on χi(k). It should be noted that the new sigma points (namely, the first key point data χi(k+1|k)) and the second measurement value obtained through transformation may also be approximated to new Gaussian distribution. Specifically, the first key point data χi(k+1|k) and the second measurement value γi(k) respectively satisfy:
f represents a status transition function. u(k) represents a control variable status. w represents a process noise. h represents a measurement function. v represents a measurement noise.
S703: Determine a prior process status and a prior process covariance based on the first key point data and a second process covariance; determine a measurement estimated value and a measurement estimated covariance based on the second measurement value and a first measurement covariance; and determine a Kalman feedback gain matrix based on the first key point data, the second measurement value, the prior process status, the measurement estimated value, and the measurement estimated covariance.
In an implementation, first, the prior process status {circumflex over (x)}(k+1|k) and the prior process covariance {circumflex over (P)}(k+1|k) may be determined based on the first key point data χi(k+1|k) and the second process covariance Q(k). In other words, prior estimation may be performed on the process status and the process covariance based on the first key point data χi(k+1|k) and the second process covariance Q(k), to obtain the prior process status {circumflex over (x)}(k+1|k) and the prior process covariance {circumflex over (P)}(k+1|k) Specifically, the prior process status {circumflex over (x)}(k+1|k) and the prior process covariance {circumflex over (P)}(k+1|k) respectively satisfy:
{circumflex over (x)}(k+1|k) represents the prior process status, namely, a process status at the moment k+1 obtained through prediction at the moment k. {circumflex over (P)}(k+1|k) represents the prior process covariance, namely, a process covariance at the moment k+1 obtained through prediction at the moment k. Wi(m) represents a weight coefficient.
Then, the measurement estimated value ŷh(k) and the measurement estimated covariance {circumflex over (P)}y(k) are determined based on the second measurement value γi(k) and the first measurement covariance R(k). In other words, estimation is performed on the measurement estimated value ŷh(k) and the measurement estimated covariance {circumflex over (P)}y(k) based on the second measurement value γi(k) and the first measurement covariance R(k). Specifically, the measurement estimated value ŷh(k) and the measurement estimated covariance {circumflex over (P)}y(k) respectively satisfy:
Further, a cross-covariance matrix {circumflex over (P)}x,y(k+1|k) is calculated based on γi(k), the measurement estimated value ŷh(k), the first key point data χi(k+1|k), and the prior process status {circumflex over (x)}(k+1|k). Specifically, the cross-covariance matrix {circumflex over (P)}x,y(k+1|k) satisfies:
Further, the Kalman feedback gain matrix K(k+1|k) is obtained through calculation based on the measurement estimated covariance {circumflex over (P)}y(k) and the cross-covariance matrix {circumflex over (P)}x,y(k+1|k). Specifically, the Kalman feedback gain matrix K(k+1|k) satisfies:
S704: Determine a posterior process status and a posterior process covariance based on the Kalman feedback gain matrix, the prior process covariance, the measurement estimated covariance, the prior process status, the measurement estimated value, and the first measurement value.
In one implementation, the posterior status {circumflex over (x)}(k+1) and the posterior process covariance {circumflex over (P)}(k+1) may be determined based on the Kalman feedback gain matrix K(k+1|k), the prior process covariance {circumflex over (P)}(k+1|k), the measurement estimated covariance {circumflex over (P)}y(k), the prior process status {circumflex over (x)}(k+1|k), the measurement estimated value ŷh(k), and the first measurement value yh(k). In other words, posterior estimation is performed on the process status and the process covariance based on the Kalman feedback gain matrix K(k+1|k), the prior process covariance {circumflex over (P)}(k+1|k), the measurement estimated covariance {circumflex over (P)}y(k), the prior process status {circumflex over (x)}(k+1|k), the measurement estimated value ŷh(k), and the first measurement value yh(k), to obtain the posterior process status {circumflex over (x)}(k+1) and the posterior process covariance {circumflex over (P)}(k+1). Specifically, the posterior process covariance {circumflex over (P)}(k+1) and the posterior process status {circumflex over (x)}(k+1) respectively satisfy:
It should be noted that the posterior process covariance {circumflex over (P)}(k+1) is a process covariance at the moment k+1 that is obtained through prediction. The posterior process status {circumflex over (x)}(k+1) is a process status at the moment k+1 that is obtained through prediction.
S705: Determine a vehicle status parameter of a vehicle based on the posterior process status.
In an implementation, a vehicle status parameter ŷg(k+1) at the moment k+1 is determined based on the posterior process status {circumflex over (x)}(k+1). Specifically, the vehicle status parameter at the moment k+1 may be comprehensively estimated based on the posterior process status {circumflex over (x)}(k+1) and the control variable status u(k).
ŷg(k+1) represents the vehicle status parameter at the moment k+1. g represents an output function.
It should be noted that the posterior process covariance {circumflex over (P)}(k+1) and the posterior process status {circumflex over (x)}(k+1) may be used as inputs of a vehicle status parameter estimation at a moment k+2, that is, the posterior process covariance {circumflex over (P)}(k+1) may be used as a sampling value of a new process covariance, and the posterior process status {circumflex over (x)}(k+1) may be used as a sampling value of a new process status, to estimate a vehicle status at a next moment of a current moment. Alternatively, it is understood that in this embodiment of this application, a vehicle status parameter at a current moment may be estimated based on a vehicle status at a previous moment of the current moment. In other words, the foregoing steps S701 to S704 may be performed cyclically based on the new process status and the process covariance generated by the posterior estimation.
In this application, in a process of estimating the vehicle status parameter, the process covariance and the measurement covariance are adaptively adjusted based on the driving status data, and then an adjusted process covariance and measurement covariance are used for a vehicle status estimation, so that estimation precision of the vehicle status parameter can be improved. In addition, in this application, a result obtained by introducing another estimation method (for example, a kinematics-based status estimation, a neural network-based status estimation, and a vision-based status estimation) is used as the measurement value of the “virtual sensor”, the measurement value obtained through measurement of the real sensor and the calculated measurement covariance are extended, and the extended measurement value and measurement covariance are used for the vehicle status estimation. This can further improve the estimation precision of the vehicle status parameter, and help improve performance of a vehicle dynamics control algorithm.
The following describes in detail a vehicle status parameter estimation apparatus provided in this application with reference to
The transceiver unit 801 is configured to obtain driving status data of a vehicle, a first process status x, and a first process covariance Q.
The processing unit 802 is configured to determine a second process covariance Q(k) and a first measurement covariance R(k) based on the driving status data of the vehicle.
The transceiver unit 801 is configured to obtain a first measurement value yh of a vehicle sensor.
The processing unit 802 is configured to determine a vehicle status parameter of the vehicle based on the first measurement value yh, the first process status x, the first process covariance Q, the second process covariance Q(k), and the first measurement covariance R(k).
In a possible implementation, the driving status data includes one or more of the following: a lateral acceleration change rate {dot over (r)}V, a steering wheel speed {dot over (δ)}, a horizontal acceleration ay, a road adhesion coefficient μ, a front left wheel speed ωFL, a front right wheel speed ωFR, a rear left wheel speed ωRL, or a rear right wheel speed ωRR.
In a possible implementation, the processing unit 802 is configured to:
In a possible implementation, the processing unit 802 is configured to:
In a possible implementation, the processing unit 802 is configured to:
In a possible implementation, the first measurement value yh of the vehicle sensor includes a measurement value measured by a real vehicle sensor and a measurement value obtained based on a virtual vehicle sensor, and the measurement value of the virtual vehicle sensor is obtained by using a neural network.
In a possible implementation, the first process status x includes one or more of the following:
In a possible implementation, the first measurement value yh includes one or more of the following:
In a possible implementation, the vehicle status parameter includes one or more of the following:
The processor 901 may be one or more central processing units (CPUs). When the processor 901 is one CPU, the CPU may be a single-core CPU or a multi-core CPU.
The processor 901 is configured to: read a program stored in the memory, and cooperate with the communication interface 902 to perform some or all steps of the method performed by the vehicle status parameter estimation apparatus in the foregoing embodiment of this application.
The memory 903 includes but is not limited to a random access memory (RAM), an erasable programmable read-only memory (EPROM), a read-only memory (ROM) or a compact disc read-only memory (CD-ROM), or the like. The memory 903 is configured to store a program, and the processor 901 may read the program stored in the memory 903. The steps in the methods shown in
The processor 1001 may be configured to read and execute computer-readable instructions. In a specific implementation, the processor 1001 may mainly include a controller, an arithmetic unit, and a register. The controller is mainly responsible for instruction decoding, and sends a control signal for an operation corresponding to the instruction. The arithmetic unit is mainly responsible for performing a fixed-point or floating-point arithmetic operation, a shift operation, a logic operation, and the like, and may also perform an address operation and address translation. The register is mainly responsible for saving a quantity of register operations, intermediate operation results, and the like that are temporarily stored during instruction execution. In a specific implementation, a hardware architecture of the processor 1001 may be an application-specific integrated circuit (ASIC) architecture, an MIPS architecture, an ARM architecture, an NP architecture, or the like. The processor 1001 may have a single core or a plurality of cores.
The communication interface 1002 may be configured to input to-be-processed data to the processor 1001, and may output a processing result of the processor 1001. For example, the communication interface 1002 may be a general-purpose input/output (GPIO) interface, and may be connected to a plurality of peripheral devices (such as a display (LCD), a camera, and a radio frequency (RF) module). The communication interface 1002 is connected to the processor 1001 through a bus 1003.
In this application, the processor 1001 may be configured to: invoke, from a memory, an implementation program of the vehicle status parameter estimation method provided in one or more embodiments of this application, and execute instructions included in the program. The communication interface 1002 may be configured to output an execution result of the processor 1001. In this application, the communication interface 1002 may be specifically configured to output a vehicle status parameter estimation result of the processor 1001. For the vehicle status parameter estimation method provided in one or more embodiments of this application, refer to the embodiments shown in
It should be noted that functions corresponding to the processor 1001 and the communication interface 1002 may be implemented by using a hardware design, or may be implemented by using a software design, or may be implemented by a combination of hardware and software. This is not limited herein.
Based on a same invention concept, problem-resolving principles and beneficial effects of the vehicle status parameter estimation apparatus provided in embodiments of this application are similar to problem-resolving principles and beneficial effects of the vehicle status parameter estimation method in the method embodiments of this application. For details, refer to the implementation principles and beneficial effects of the method. For a relationship between steps performed by related modules, refer to description of related content in the foregoing embodiment. For brevity, details are not described herein again.
An embodiment of this application further provides a computer storage medium, which may be configured to store computer software instructions used by the vehicle status parameter estimation apparatus in the embodiments shown in
An embodiment of this application further provides a computer program product. When the computer product is run by a vehicle status parameter estimation apparatus, the vehicle status parameter estimation method designed for the vehicle status parameter estimation apparatus in the embodiments shown in
An embodiment of this application further provides a sensor system, configured to provide a vehicle status parameter estimation function for a vehicle. The system includes at least one vehicle status parameter estimation apparatus mentioned in the foregoing embodiments of this application and at least one of a camera, a radar, and another sensor. At least one sensor apparatus in the system may be integrated into an overall unit or device, or at least one sensor apparatus in the system may be disposed as an independent element or apparatus.
An embodiment of this application further provides a system applied to self-driving or intelligent driving. The system includes at least one vehicle status parameter estimation apparatus mentioned in the foregoing embodiment of this application and at least one of other sensors such as a camera and a radar. At least one apparatus in the system may be integrated as an entire system or a device, or at least one apparatus in the system may be independently disposed as an element or an apparatus.
Further, any of the above systems may interact with a central controller of a vehicle to provide information such as a vehicle status parameter for decision or control of driving of the vehicle.
An embodiment of this application further provides a terminal. The terminal includes at least one vehicle status parameter estimation apparatus mentioned in the foregoing embodiments of this application or any one of the foregoing systems. For example, the terminal may include a vehicle, a camera, an uncrewed aerial vehicle, or the like. This is not limited herein.
It may be understood that sequence adjustment, combination, and deletion may be performed on the steps in the method embodiments of this application based on an actual requirement.
Modules in the apparatus embodiments of this application may be combined, divided, or deleted based on an actual requirement.
Persons of ordinary skill in the art may understand that sequence numbers of the foregoing processes do not mean execution sequences in various embodiments of this application. The execution sequences of the processes should be determined based on functions and internal logic of the processes, and should not be construed as any limitation on the implementation processes of embodiments of this application.
The foregoing descriptions are merely specific implementations of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by persons skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
This application is a continuation of International Application No. PCT/CN2021/117746, filed on Sep. 10, 2021, the disclosure of which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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Parent | PCT/CN2021/117746 | Sep 2021 | WO |
Child | 18600374 | US |