Road surface slope determination method, device and electronic equipment

Abstract

Embodiments of the present application provide a road slope determination method, device and electronic equipment, and relate to the technical field of vehicle control. The road slope determination method comprises: acquiring a vehicle body pitch angle; determining an angle between the vehicle body and the horizontal direction according to a projection relationship among the IMU longitudinal acceleration of the vehicle, the actual longitudinal acceleration of the vehicle and the gravitational acceleration; and determining a slope value in which the vehicle is located based on the angle between the vehicle body and the horizontal direction and the vehicle body pitch angle. The embodiments provided by the present application improve the accuracy of estimated slope and the safety factor of the algorithm in the application layer.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and more specifically to a method for determining road slope, a device for determining road slope, an electronic device, and a corresponding storage medium. Background Technology

[0002] In recent years, people's demands for automobiles have expanded beyond simple transportation; they now prioritize operational efficiency, driving stability, and active safety. The rapid development of sensor technology has spurred research into automotive automation, leading to extensive studies in vehicle control. However, the development of control systems, the implementation of control strategies, and the improvement of control logic largely depend on driving state parameters. These parameters refer to aspects such as speed, sideslip angle, mass, tire sideslip stiffness, and road slope during vehicle operation. Therefore, accurate real-time feedback of these driving state parameters is a key focus of current automotive automation research. Road slope, as a crucial input parameter in automotive control research, is significant for controlling the powertrain, safety systems, and energy recovery. For example, some researchers calculate the vehicle's power coefficient based on road slope, speed, and acceleration, thereby estimating the power required to overcome driving resistance and controlling energy distribution to achieve energy conservation.

[0003] Among the various methods, GPS and GIS-based geographic information querying rely on GPS information that is easily lost in special environments such as tunnels, making it impossible to obtain slope information. Methods based on vehicle dynamics depend on the accuracy of driving force signals; without sensors, vehicle driving force is difficult to observe, and these methods require numerous input parameters. In contrast, vehicle kinematics-based methods, using IMU sensors to acquire acceleration in the X, Y, and Z directions and estimating slope based on the measured actual vehicle speed, have become a current research hotspot.

[0004] Existing slope estimation algorithms all have some shortcomings. For example, some patents utilize GPS and GIS geographic information query methods, which rely heavily on GPS information, but this information is easily lost in special environments such as tunnels, making it impossible to obtain slope information. Other patents design two estimation modules. One module is based on vehicle dynamics, relying on the accuracy of the driving force signal. Without sensors, the vehicle's driving force is difficult to observe, and this method requires many input parameters, making redundant handling of sensor failures difficult. The other estimation module is based on vehicle kinematics, using an IMU sensor to obtain acceleration in the X, Y, and Z directions and estimating the slope based on the measured actual vehicle speed. This method requires less input signal and can quickly estimate the actual slope. However, when a car travels on a slope, the vehicle body pitches, and the pitch angle affects the direction of acceleration measured by the IMU sensor. Therefore, slope estimation without considering the pitch angle will introduce some error.

[0005] IMU (Inertial Measurement Unit): An inertial sensor or inertial measurement unit is a device used to measure the three-axis attitude angles and acceleration of an object. Summary of the Invention

[0006] The purpose of this invention is to provide a method, apparatus, and electronic device for determining road slope, which uses vehicle kinematics methods, employs an IMU sensor to acquire longitudinal acceleration, and estimates the slope based on the measured actual longitudinal vehicle speed, thereby at least solving some of the problems in the background art.

[0007] To achieve the above objectives, the present invention provides a method for determining road slope, the method comprising: obtaining the vehicle body pitch angle; determining the angle between the vehicle body and the horizontal direction based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration; and determining the slope value of the vehicle based on the angle between the vehicle body and the horizontal direction and the vehicle body pitch angle.

[0008] Preferably, obtaining the vehicle pitch angle includes: determining the vehicle pitch angle based on the difference in vertical displacement between the front and rear wheels and the vehicle's front and rear track width.

[0009] Preferably, determining the vehicle pitch angle based on the difference in vertical displacement between the front and rear wheels and the vehicle's front and rear track width includes: calculating the quotient of the difference in vertical displacement between the front and rear wheels divided by the front and rear track width; and mapping the quotient using an arctangent function to obtain the vehicle pitch angle.

[0010] Preferably, determining the angle between the vehicle body and the horizontal direction based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration includes: subtracting the projection of the vehicle's actual longitudinal acceleration onto the IMU longitudinal acceleration direction based on the vehicle body pitch angle from the vehicle's IMU longitudinal acceleration to obtain an intermediate acceleration value; using the intermediate acceleration value as the projection of gravitational acceleration onto the IMU longitudinal acceleration direction, calculating the angle between the intermediate acceleration value and gravitational acceleration; and using the angle between the intermediate acceleration value and gravitational acceleration as the angle between the vehicle body and the horizontal direction.

[0011] Preferably, the intermediate acceleration value is used as the projection of gravitational acceleration onto the longitudinal acceleration direction of the IMU. The angle between the intermediate acceleration value and gravitational acceleration is calculated by: calculating the quotient of the intermediate acceleration value divided by gravitational acceleration; and mapping the quotient using an arcsine function to obtain the angle between the intermediate acceleration value and gravitational acceleration.

[0012] Preferably, the method further includes: acquiring output signals from front and rear wheel displacement sensors based on the acquired data; determining whether the output signals are within a displacement value range based on the actual vehicle calibration; when the output signals are within the displacement value range based on the actual vehicle calibration, filtering the output signals based on a first cutoff frequency of the actual vehicle calibration, and obtaining the vertical displacement of the front and rear wheels after analysis.

[0013] Preferably, the method further includes: acquiring an output signal from the inertial measurement unit of the vehicle based on the acquired data; determining whether the output signal is within the range of inertial values ​​calibrated based on the actual vehicle; and when the output signal is within the range of inertial values ​​calibrated based on the actual vehicle, filtering the output signal based on a second cutoff frequency calibrated based on the actual vehicle to obtain the longitudinal acceleration of the IMU.

[0014] Preferably, the method further includes: acquiring the actual longitudinal vehicle speed signal output by the vehicle speed sensor; determining whether the actual longitudinal vehicle speed signal is within the range of vehicle speed values ​​calibrated based on the actual vehicle; when the actual longitudinal vehicle speed signal is within the range of inertial values ​​calibrated based on the actual vehicle, using the average sampling time of the vehicle speed sensor as the time step, subtracting the actual longitudinal vehicle speed before the previous time step from the actual longitudinal vehicle speed at the current moment and dividing by the time step to obtain the actual longitudinal acceleration at the previous moment; and filtering the actual longitudinal acceleration at the previous moment based on the third cutoff frequency calibrated based on the actual vehicle to obtain the actual longitudinal acceleration.

[0015] Preferably, after obtaining the slope value where the vehicle is located, the method further includes: verifying the obtained slope value to determine whether the calculation device for determining the slope value is faulty; and when the calculation device is not faulty, outputting the calculated slope value in real time.

[0016] The present invention also provides a road slope determination device, which includes: a pitch determination module for obtaining the vehicle pitch angle; an angle calculation module for determining the angle between the vehicle body and the horizontal direction based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration; and a slope output module for determining the slope value of the vehicle based on the angle between the vehicle body and the horizontal direction and the vehicle pitch angle.

[0017] The present invention also provides an electronic device, comprising: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the at least one processor implements the steps of the aforementioned road slope determination method by executing the instructions stored in the memory.

[0018] The present invention also provides a machine-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform the steps of implementing the aforementioned road slope determination method.

[0019] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the aforementioned road surface slope determination method.

[0020] The above technical solution has the following beneficial effects:

[0021] 1. Based on vehicle kinematics, the slope of the road surface is estimated in real time by making full use of IMU sensors. The calculation process is simple and efficient, reducing the computational requirements of the ECU.

[0022] 2. The impact of vehicle pitch on the slope calculation results was considered when calculating the slope, which improved the accuracy of slope estimation.

[0023] 3. Redundancy handling is considered in the event of sensor and computing device failures, which improves the safety and robustness of the algorithm at the application level.

[0024] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0025] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0026] Figure 1 The schematic diagram illustrates the steps of a method for determining road slope according to an embodiment of the present invention;

[0027] Figure 2 A schematic diagram illustrating the motion analysis of a vehicle traveling uphill and pitching backward according to an embodiment of the present invention is shown.

[0028] Figure 3 This schematic diagram illustrates the principle of calculating the pitch angle when a vehicle pitches backward according to an embodiment of the present invention.

[0029] Figure 4 A motion analysis diagram of an IMU sensor according to an embodiment of the present invention is illustrated schematically;

[0030] Figure 5 A flowchart illustrating the implementation of the road slope determination algorithm according to an embodiment of the present invention is shown.

[0031] Figure 6 A schematic diagram of the road slope determination device according to an embodiment of the present invention is shown.

[0032] Figure 7 A schematic diagram of a road slope determination device according to an embodiment of the present invention is shown. Detailed Implementation

[0033] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0034] Figure 1 The diagram illustrates the steps of a road surface slope determination method according to an embodiment of the present invention. Figure 1 As shown, a method for determining road surface slope includes:

[0035] S01, Obtain the vehicle pitch angle;

[0036] S02. Determine the angle between the vehicle body and the horizontal direction based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration.

[0037] S03. Determine the slope value of the vehicle based on the angle between the vehicle body and the horizontal direction and the vehicle body pitch angle.

[0038] The above implementation method takes into account the pitch phenomenon generated by the vehicle body during driving, and thus corrects for the slope value, resulting in a more accurate slope calculation. Furthermore, this implementation method is based on vehicle kinematics, making the calculation process simple and efficient, reducing the computational requirements of the ECU.

[0039] This implementation method calculates the slope based on the longitudinal driving state, which is the general state of vehicle movement. Vehicles will be in this state for a long time, and only in a few cases such as turning will they be in the lateral driving state. Therefore, using the longitudinal driving state has the advantages of simple calculation, convenient signal acquisition, fewer control variables, and greater stability.

[0040] Figure 2 A schematic diagram illustrating the motion analysis of a vehicle according to an embodiment of the present invention when traveling uphill and pitching backward. For example... Figure 2 As shown, when a vehicle is traveling uphill, it has a slope angle of θs and a pitch angle of θp between the vehicle body and the road surface. The combined angle of these two angles is θ. Taking the direction perpendicular to the vehicle body as the Y-axis, the angle between the gravitational acceleration and the Y-axis is also θ. Therefore, the above angles have the following relationship:

[0041] θ s =θ-θ p

[0042] Figure 2 The direction of acceleration in v is analyzed as follows: x The actual longitudinal speed is given by the derivative of the actual longitudinal speed, which yields the actual longitudinal acceleration. The IMU sensor is subjected to two opposing accelerations in the longitudinal direction, namely the actual longitudinal acceleration of the vehicle body. The projection of the two accelerations, g and g, onto the direction parallel to the vehicle body is the acceleration a measured by the IMU sensor. x .

[0043] In some embodiments of the present invention, the vehicle pitch angle is determined based on the difference in vertical displacement between the front and rear wheels and the vehicle's front and rear track width. Figure 3 A schematic diagram illustrating the principle of calculating the pitch angle when a vehicle pitches backward according to an embodiment of the present invention is shown. Figure 3 As shown, assuming the vehicle body is in a backward-leaning state, the front suspension is stretched and the rear suspension is compressed, and the angle formed between the vehicle body and the road surface is the pitch angle θp. The magnitude of the pitch angle can be calculated based on the relationship between the vertical displacement F of the front wheels, the vertical displacement R of the rear wheels, and the distance L between the front and rear wheels. The formula for calculating the pitch angle is:

[0044]

[0045] In some embodiments of the present invention, determining the angle between the vehicle body and the horizontal direction based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration includes: subtracting the projection of the vehicle's actual longitudinal acceleration onto the IMU longitudinal acceleration direction based on the vehicle body pitch angle from the vehicle's IMU longitudinal acceleration to obtain an intermediate acceleration value; using the intermediate acceleration value as the projection of gravitational acceleration onto the IMU longitudinal acceleration direction, calculating the angle between the intermediate acceleration value and gravitational acceleration; and using the angle between the intermediate acceleration value and gravitational acceleration as the angle between the vehicle body and the horizontal direction. Figure 4 A motion analysis diagram of an IMU sensor according to an embodiment of the present invention is illustrated schematically. Figure 4 As shown, according to the principles of kinematics, the acceleration a measured by the IMU sensor... x The actual longitudinal acceleration of the vehicle body The sum of the projections of gravitational acceleration g onto the x-axis can be used to derive the formula:

[0046]

[0047] Therefore, θ can be determined based on the gravitational acceleration g and the actual longitudinal acceleration of the vehicle body. Acceleration a measured by the IMU sensor x Solving for the relationship, based on the previous formula, yields:

[0048]

[0049] in, Let be the aforementioned intermediate acceleration value. First, calculate the quotient of this intermediate acceleration value divided by the gravitational acceleration. Then, use the arcsine function to map the quotient to obtain the angle between the intermediate acceleration value and the gravitational acceleration. Finally, through the aforementioned angle relationship and mathematical formula transformation, the formula for calculating the actual road surface slope is:

[0050]

[0051] This gives us the slope value where the vehicle is located.

[0052] In some embodiments of the present invention, the method further includes: acquiring output signals from front and rear wheel displacement sensors based on the acquired data; determining whether the output signals are within a displacement value range based on vehicle calibration; when the output signals are within the displacement value range based on vehicle calibration, filtering the output signals based on a first cutoff frequency of vehicle calibration, and obtaining the vertical displacement of the front and rear wheels after analysis. The front and rear wheel displacement sensors are sensors that measure the displacement of the front and rear wheels of a vehicle, and their models or types are selected according to the actual scenario. After acquiring the output signals, it is necessary to verify whether the acquired output signals are within a reasonable range, thereby determining whether the sensor is faulty. If the sensor is faulty, a default slope value of 0 is directly output and a relevant fault command is sent, then the process ends. If the sensor is not faulty, the next step is performed. To further improve the output signal quality, low-frequency noise reduction processing is required on the output signals of the front and rear wheel displacement sensors. The output signals are low-pass filtered using a specified relevant cutoff frequency, allowing high frequencies to be cut off and low frequencies to pass, thereby achieving signal noise reduction. In this embodiment, the first cutoff frequency needs to be given a suitable value through vehicle calibration.

[0053] In some embodiments of the present invention, the method further includes: acquiring an output signal from the inertial measurement unit (IMU) of the vehicle based on the acquired data; determining whether the output signal is within the range of inertial values ​​calibrated based on the actual vehicle; and when the output signal is within the range of inertial values ​​calibrated based on the actual vehicle, filtering the output signal based on a second cutoff frequency calibrated based on the actual vehicle to obtain the longitudinal acceleration of the IMU. Similar to the processing of the output signals from the front and rear wheel displacement sensors, the acquired output signal is verified to see if it is within a reasonable range, thereby determining whether the sensor is faulty. If the sensor is faulty, a default slope value of 0 is directly output and a relevant fault command is sent, then the process ends. If the sensor is not faulty, the next step is performed. To further improve the quality of the output signal, low-frequency noise reduction processing is also required on the output signal of the inertial measurement unit. The output signal is low-pass filtered using a specified relevant cutoff frequency, allowing high frequencies to be cut off and low frequencies to pass, thereby achieving signal noise reduction. In this embodiment, the second cutoff frequency needs to be given a suitable value through actual vehicle calibration.

[0054] In some embodiments of the present invention, the method further includes: acquiring the actual longitudinal vehicle speed signal output by the vehicle speed sensor; determining whether the actual longitudinal vehicle speed signal is within a vehicle speed value range calibrated based on the actual vehicle; when the actual longitudinal vehicle speed signal is within the inertial value range calibrated based on the actual vehicle, using the average sampling time of the vehicle speed sensor as the time step, subtracting the actual longitudinal vehicle speed before the previous time step from the current actual longitudinal vehicle speed and dividing by the time step to obtain the actual longitudinal acceleration at the previous moment; filtering the actual longitudinal acceleration at the previous moment based on the third cutoff frequency calibrated by the actual vehicle to obtain the actual longitudinal acceleration. In this embodiment, the actual longitudinal acceleration is calculated based on the actual vehicle speed and acceleration calculation formula. For example, based on the actual longitudinal vehicle speed signal, the actual longitudinal acceleration is calculated by differentiation within a specified time step, where the time step is the average sampling time of the sensor. The actual longitudinal vehicle speed at the current moment is subtracted from the actual longitudinal vehicle speed before the previous time step and then divided by the time step to obtain the actual longitudinal acceleration at the previous moment. The actual longitudinal acceleration is then transmitted to the low-pass filter module for filtering and noise reduction.

[0055] In some embodiments of the present invention, after obtaining the slope value of the vehicle, the method further includes: verifying the obtained slope value to determine whether the calculation device used to determine the slope value is faulty; and outputting the calculated slope value in real time when the calculation device is not faulty. This embodiment provides a verification step for the calculated slope value, determining whether the calculation device is faulty by judging whether the calculated value is within a reasonable range. The reasonable range here can be determined by road slope specifications. For example, according to regulations, the road slope of different types of road surfaces is no greater than 5% to 8%, which is converted into angle values ​​to obtain the aforementioned reasonable range. If the calculation device malfunctions, a default slope value of 0 is directly output, a relevant fault command is sent, and then the process ends. If the calculation device is not faulty, the calculated slope value is sent in real time, and then the process ends. This embodiment enhances the robustness of the slope determination method.

[0056] In some embodiments of the present invention, determining the vehicle pitch angle based on the difference in vertical displacement between the front and rear wheels and the vehicle's track width includes: calculating the quotient of the difference in vertical displacement between the front and rear wheels divided by the track width; and mapping the quotient to obtain the vehicle pitch angle using an arctangent function. That is, the aforementioned formula for calculating θp is as described above and will not be repeated here.

[0057] In some embodiments of the present invention, the intermediate acceleration value is used as the projection of gravitational acceleration onto the longitudinal acceleration direction of the IMU. Calculating the angle between the intermediate acceleration value and the gravitational acceleration includes: calculating the quotient of the intermediate acceleration value divided by the gravitational acceleration; and mapping the quotient using an arcsine function to obtain the angle between the intermediate acceleration value and the gravitational acceleration. That is, the aforementioned formula for calculating θ is as described above and will not be repeated here.

[0058] Through the above implementation method, the influence of pitch angle on the calculated slope value is considered when calculating the slope value based on the IMU sensor, thereby improving the accuracy of the estimated slope.

[0059] Figure 5 A schematic flowchart illustrating the implementation of a road slope determination algorithm according to an embodiment of the present invention is shown. Figure 5 As shown, this implementation includes the following steps:

[0060] The first step is to use the vehicle's built-in sensors to acquire the actual longitudinal speed signal, front and rear wheel displacement signals, and IMU longitudinal acceleration signal.

[0061] The second step is to verify the acquired signal to see if the signal value is within a reasonable range, thereby determining whether the sensor is faulty. If the sensor is faulty, the default slope value of 0 is output directly, and a relevant fault command is sent, then the process ends; if the sensor is not faulty, the next step is performed.

[0062] The third step is to perform differential calculations on the actual longitudinal vehicle speed signal to obtain the actual longitudinal acceleration.

[0063] The fourth step is to reduce noise by low-pass filtering the actual acceleration, front and rear wheel displacement signals, and IMU longitudinal acceleration signal.

[0064] The fifth step is to calculate the vehicle pitch angle using the front and rear wheel displacement signals. Then, using the vehicle pitch angle, actual acceleration, and IMU longitudinal acceleration, the gradient value is calculated.

[0065] The sixth step is to verify the calculated slope value to see if it is within a reasonable range, thereby determining whether the calculation device is malfunctioning. If the calculation device is malfunctioning, the default slope value of 0 is output directly, and a relevant fault command is sent, then the process ends; if the calculation device is not malfunctioning, the calculated slope value is sent in real time, then the process ends.

[0066] As can be seen from the above implementation methods, this implementation method, while calculating the slope value, also considers the redundancy processing when the sensor and computing device fail, thereby improving the safety factor of the algorithm at the application level.

[0067] Based on the same inventive concept, the present invention also provides a road surface slope determination device. Figure 6 A schematic diagram of a road slope determination device according to an embodiment of the present invention is shown. Figure 6 As shown, the device includes: a pitch determination module for acquiring the vehicle's pitch angle; an angle calculation module for determining the angle between the vehicle body and the horizontal direction based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration; and a slope output module for determining the slope value of the vehicle based on the angle between the vehicle body and the horizontal direction and the vehicle's pitch angle.

[0068] In some alternative implementations, obtaining the vehicle pitch angle includes: determining the vehicle pitch angle based on the difference between the vertical displacements of the front and rear wheels and the vehicle's front and rear track width.

[0069] In some alternative implementations, determining the vehicle pitch angle based on the difference in vertical displacement between the front and rear wheels and the vehicle's track width includes: calculating the quotient of the difference in vertical displacement between the front and rear wheels divided by the track width; and mapping the quotient to obtain the vehicle pitch angle using an arctangent function.

[0070] In some optional implementations, the angle between the vehicle body and the horizontal direction is determined based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration. This includes: subtracting the projection of the vehicle's actual longitudinal acceleration onto the IMU longitudinal acceleration direction based on the vehicle body pitch angle from the vehicle's IMU longitudinal acceleration to obtain an intermediate acceleration value; using the intermediate acceleration value as the projection of gravitational acceleration onto the IMU longitudinal acceleration direction, calculating the angle between the intermediate acceleration value and gravitational acceleration; and using the angle between the intermediate acceleration value and gravitational acceleration as the angle between the vehicle body and the horizontal direction.

[0071] In some optional implementations, the intermediate acceleration value is used as the projection of gravitational acceleration onto the longitudinal acceleration direction of the IMU. The angle between the intermediate acceleration value and gravitational acceleration is calculated by: calculating the quotient of the intermediate acceleration value divided by gravitational acceleration; and mapping the quotient using an arcsine function to obtain the angle between the intermediate acceleration value and gravitational acceleration.

[0072] In some optional embodiments, the device further includes: acquiring output signals based on the acquired data from the front and rear wheel displacement sensors; determining whether the output signals are within a displacement value range based on the actual vehicle calibration; and when the output signals are within the displacement value range based on the actual vehicle calibration, filtering the output signals based on a first cutoff frequency of the actual vehicle calibration, and obtaining the vertical displacement of the front and rear wheels after analysis.

[0073] In some alternative embodiments, the apparatus further includes: acquiring an output signal from the inertial measurement unit of the vehicle based on the acquired data; determining whether the output signal is within the range of inertial values ​​calibrated based on the actual vehicle; and when the output signal is within the range of inertial values ​​calibrated based on the actual vehicle, filtering the output signal based on a second cutoff frequency calibrated based on the actual vehicle to obtain the longitudinal acceleration of the IMU.

[0074] In some optional embodiments, the apparatus further includes: acquiring an actual longitudinal vehicle speed signal output from a vehicle speed sensor; determining whether the actual longitudinal vehicle speed signal is within a vehicle speed value range calibrated based on the actual vehicle; when the actual longitudinal vehicle speed signal is within the inertial value range calibrated based on the actual vehicle, using the average sampling time of the vehicle speed sensor as the time step, subtracting the actual longitudinal vehicle speed before the previous time step from the current actual longitudinal vehicle speed and dividing by the time step to obtain the actual longitudinal acceleration at the previous moment; and filtering the actual longitudinal acceleration at the previous moment based on a third cutoff frequency calibrated based on the actual vehicle to obtain the actual longitudinal acceleration.

[0075] In some optional embodiments, after obtaining the slope value where the vehicle is located, the device further includes a slope verification module, which is used to: verify the obtained slope value, determine whether the calculation device for determining the slope value is faulty; and output the calculated slope value in real time when the calculation device is not faulty.

[0076] In some alternative implementations, determining the vehicle pitch angle based on the difference in vertical displacement between the front and rear wheels and the vehicle's track width includes: calculating the quotient of the difference in vertical displacement between the front and rear wheels divided by the track width; and mapping the quotient to obtain the vehicle pitch angle using an arctangent function.

[0077] In some optional implementations, the intermediate acceleration value is used as the projection of gravitational acceleration onto the longitudinal acceleration direction of the IMU. The angle between the intermediate acceleration value and gravitational acceleration is calculated by: calculating the quotient of the intermediate acceleration value divided by gravitational acceleration; and mapping the quotient using an arcsine function to obtain the angle between the intermediate acceleration value and gravitational acceleration.

[0078] The specific limitations of each functional module in the aforementioned road slope determination device can be found in the limitations of the road slope determination method described above, and will not be repeated here. Each module in the aforementioned device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module. It also has the advantages of improved accuracy in slope estimation and redundant processing.

[0079] Figure 7 A schematic diagram of a road slope determination device according to an embodiment of the present invention is shown. Figure 7 As shown, this embodiment mainly consists of a sensor group 1 and a slope calculation group 2. The signal from the sensor group 1 is input to the slope calculation group 2 via a CAN line, and the slope calculation group 2 sends the slope calculation value and related instructions in real time based on the relevant calculation results.

[0080] Sensor group 1 mainly includes a vehicle body IMU sensor, a real-time vehicle speed sensor, and front and rear wheel displacement sensors. The vehicle body IMU sensor in sensor group 1 is the key sensor, utilizing the principle of inertia to output the acceleration of the IMU sensor relative to each coordinate axis of the vehicle body. Its longitudinal acceleration direction is always parallel to the vehicle body. The IMU sensor defines the direction perpendicular to the vehicle body and upward as the positive direction. When the car is stationary on a level road, the IMU sensor has a positive gravitational acceleration. The real-time vehicle speed sensor in sensor group 1 can provide real-time feedback on the actual vehicle speed relative to each coordinate axis of the road surface, and its longitudinal speed direction is always parallel to the road surface. The front and rear wheel displacement sensors in sensor group 1 can provide real-time feedback on the displacement of the front and rear wheels based on the tension and compression states of the front and rear suspensions, and their displacement direction is always perpendicular to the road surface.

[0081] The slope calculation group 2 mainly includes a signal verification module, an actual acceleration calculation module, a low-pass filter module, a vehicle pitch angle calculation module, and a slope estimation module.

[0082] The signal verification module of the slope calculation group 2 mainly receives and verifies the signals from sensor group 1 to see if the signal values ​​are within a reasonable range, thereby determining whether the sensors are faulty. If a fault occurs, it directly outputs a default slope value of 0 and sends a relevant fault command, then terminates the calculation. If the sensor is not faulty, it passes the signal value to the actual acceleration calculation module and the low-pass filter module. The numerical range needs to be calibrated to a suitable value through actual vehicle testing. The actual acceleration calculation module of the slope calculation group 2 mainly calculates the actual longitudinal acceleration based on the actual longitudinal vehicle speed signal by differentiating it at a specified time step. The time step is taken as the average sampling time of the sensor. The actual longitudinal vehicle speed at the current moment is subtracted from the actual longitudinal vehicle speed at the previous time step and then divided by the time step to obtain the actual longitudinal acceleration at the previous moment. The actual longitudinal acceleration is then passed to the low-pass filter module. The low-pass filter module of the slope calculation group 2 performs low-frequency noise reduction processing on the actual longitudinal acceleration, the vehicle body IMU sensor signal, and the front and rear wheel displacement sensor signal. It specifies a relevant cutoff frequency to cut off high frequencies and allow low frequencies to pass, thereby achieving the purpose of signal noise reduction. The cutoff frequency needs to be given a suitable value through actual vehicle calibration. Slope Calculation Group 2: Vehicle Pitch Angle Calculation Module. Based on vehicle kinematics formulas, it calculates the vehicle pitch angle using front and rear wheel displacement sensor signals and transmits the pitch angle to the slope estimation module. Slope Calculation Group 2: Slope Estimation Module. Based on vehicle kinematics formulas, it estimates the current vehicle slope using vehicle IMU sensor signals, actual longitudinal speed, and vehicle pitch angle.

[0083] Each module in the above slope calculation group 2 can be implemented in whole or in part by software, hardware and their combination. It is different from the module name in the previous embodiment, but has the same beneficial effects as mentioned above.

[0084] In some embodiments of the present invention, an electronic device is also provided, comprising: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which performs the steps of the aforementioned road slope determination method. The control module or processor here has numerical calculation and logical operation functions, and at least has a central processing unit (CPU) with data processing capabilities, random access memory (RAM), read-only memory (ROM), various I / O ports, and an interrupt system. The processor contains a kernel that retrieves corresponding program units from the memory. One or more kernels can be configured, and the aforementioned method can be implemented by adjusting kernel parameters. The memory may include non-permanent memory in a computer-readable medium, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and includes at least one memory chip.

[0085] In one embodiment of the present invention, a machine-readable storage medium is provided, on which instructions are stored, which, when executed by a processor, cause the processor to be configured to perform the steps of the aforementioned road slope determination method.

[0086] In one embodiment of the present invention, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the aforementioned road surface slope determination method.

[0087] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0088] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0089] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0090] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0091] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0092] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0093] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0094] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0095] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for determining road surface slope, characterized in that, The method includes: Obtain the vehicle body pitch angle; The angle between the vehicle body and the horizontal direction is determined based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration. The slope value of the vehicle is determined based on the angle between the vehicle body and the horizontal direction and the vehicle body pitch angle. The method further includes: acquiring output signals based on the collected data from the front and rear wheel displacement sensors; determining whether the output signals are within the displacement value range based on the actual vehicle calibration; when the output signals are within the displacement value range based on the actual vehicle calibration, filtering the output signals based on the first cutoff frequency of the actual vehicle calibration, and obtaining the vertical displacement of the front and rear wheels after analysis. After obtaining the slope value where the vehicle is located, the method further includes: verifying the obtained slope value to determine whether the calculation device for determining the slope value is faulty; and outputting the calculated slope value in real time when the calculation device is not faulty.

2. The method according to claim 1, characterized in that, The process of obtaining the vehicle pitch angle includes: determining the vehicle pitch angle based on the difference in vertical displacement between the front and rear wheels and the vehicle's front and rear track width.

3. The method according to claim 2, characterized in that, The vehicle pitch angle is determined based on the difference in vertical displacement between the front and rear wheels and the vehicle's track width, including: Calculate the difference in vertical displacement between the front and rear wheels, divided by the distance between the front and rear wheels; The vehicle body pitch angle is obtained by mapping the quotient using the arctangent function.

4. The method according to claim 1, characterized in that, The angle between the vehicle body and the horizontal direction is determined based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration, including: The intermediate acceleration value is obtained by subtracting the projection of the vehicle's actual longitudinal acceleration based on the vehicle body pitch angle onto the longitudinal acceleration direction of the IMU from the vehicle's IMU longitudinal acceleration. Using the median acceleration value as the projection of gravitational acceleration onto the longitudinal acceleration direction of the IMU, calculate the angle between the median acceleration value and the gravitational acceleration. The angle between the median acceleration and the gravitational acceleration is taken as the angle between the vehicle body and the horizontal direction.

5. The method according to claim 4, characterized in that, Using the median acceleration value as the projection of gravitational acceleration onto the longitudinal acceleration direction of the IMU, the angle between the median acceleration value and the gravitational acceleration is calculated, including: Calculate the quotient of the intermediate value of acceleration divided by the acceleration due to gravity; The angle between the intermediate value of the acceleration and the gravitational acceleration is obtained by mapping the quotient using the arcsine function.

6. The method according to claim 1, characterized in that, The method further includes: Acquire the output signal based on the acquired data from the vehicle's inertial measurement unit; Determine whether the output signal is within the range of inertial values ​​calibrated based on the actual vehicle; When the output signal is within the range of the inertial value based on the actual vehicle calibration, the output signal is filtered based on the second cutoff frequency of the actual vehicle calibration to obtain the longitudinal acceleration of the IMU.

7. The method according to claim 1, characterized in that, The method further includes: Acquire the actual longitudinal vehicle speed signal output from the vehicle's speed sensor; Determine whether the actual longitudinal vehicle speed signal is within the range of vehicle speed values ​​calibrated based on the actual vehicle; When the actual longitudinal vehicle speed signal is within the range of inertial values ​​calibrated based on the actual vehicle, the average sampling time of the vehicle speed sensor is used as the time step. The actual longitudinal vehicle speed at the current moment is subtracted from the actual longitudinal vehicle speed before the previous time step and then divided by the time step to obtain the actual longitudinal acceleration at the previous moment. The actual longitudinal acceleration at the previous moment is obtained by filtering the actual longitudinal acceleration based on the third cutoff frequency calibrated by the actual vehicle.

8. A road surface slope determination device, characterized in that, The device includes: The pitch determination module is used to obtain the vehicle body pitch angle; The angle calculation module is used to determine the angle between the vehicle body and the horizontal direction based on the projection relationship between the vehicle's IMU longitudinal acceleration, the vehicle's actual longitudinal acceleration, and gravitational acceleration; and The slope output module is used to determine the slope value of the vehicle based on the angle between the vehicle body and the horizontal direction and the vehicle body pitch angle. The device further includes: acquiring output signals based on the collected data from the front and rear wheel displacement sensors; determining whether the output signals are within the displacement value range calibrated based on the actual vehicle; when the output signals are within the displacement value range calibrated based on the actual vehicle, filtering the output signals based on the first cutoff frequency calibrated based on the actual vehicle, and obtaining the vertical displacement of the front and rear wheels after analysis. After obtaining the slope value of the vehicle, the device further includes: verifying the obtained slope value to determine whether the calculation device for the slope value is faulty; and outputting the calculated slope value in real time when the calculation device is not faulty.

9. An electronic device, characterized in that, include: At least one processor; A memory connected to the at least one processor; The memory stores instructions executable by the at least one processor, which executes the steps of the road slope determination method according to any one of claims 1 to 7 by executing the instructions stored in the memory.

10. A vehicle, characterized in that, The vehicle includes front and rear wheel displacement sensors, an inertial measurement unit, and a vehicle speed sensor, and includes the road slope determination device of claim 8 or the electronic device of claim 9.

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