VEHICLE WITH A GROUND CLEARANCE SYSTEM

Abstract

Vehicle with a ground clearance monitoring system, including: an electromagnetic source (30) designed to output a coded magnetic signal at a specified frequency, wherein the frequency is selected depending on the desired control speed of the ground clearance sensing system, with a higher frequency being selected for a faster control speed; at least two magnetometers (54, 31) designed to acquire magnetic field data, wherein at least one magnetometer (54) is arranged at a defined distance from the electromagnetic source (30); and a controller (110) designed to filter the acquired data using a frequency bandpass filter in order to extract the coded magnetic signal and determine a change in the ground clearance of a vehicle body (12).

Description

TECHNICAL AREA

[0001] The present disclosure relates generally to a coded ground clearance sensing system for a vehicle based on an electromagnet. In particular, the ground clearance sensing system of the present disclosure comprises a coded electromagnetic source and one or more magnetometers, such as Hall effect sensors, to determine a change in the ground clearance of a vehicle body. GENERAL STATE OF THE ART

[0002] Drivers frequently encounter obstacles on the road, such as potholes, rocks, fallen branches, and other debris. These obstacles cause the vehicle body to move relative to its wheels, resulting in a change in the distance between the vehicle's chassis and the ground, commonly referred to as ground clearance. Vehicles are equipped with ground clearance sensing systems to detect this change in ground clearance and adjust the vehicle's suspension accordingly.

[0003] Ground clearance sensing systems measure the distance between a designated point on a vehicle's chassis, suspension, or body and the ground. As the vehicle is loaded and unloaded, these systems detect changes in ground clearance and provide input to the vehicle's suspension system to adjust how the suspension responds to altered road conditions or loads. By using a vehicle's suspension system, the vehicle can provide a smoother ride on a bumpy road, a lower ride height to improve aerodynamics at high speeds, or a higher ride height for increased ground clearance off-road.

[0004] Existing ground clearance measurement systems rely on physical links that are susceptible to impact damage and require moving parts and levers, thus preventing accurate readings. Other existing non-linkage-based ground clearance measurement systems include those using ultrasonic lasers. A disadvantage of these systems is that they require a line of sight between a reflector and a transmitter, and the transmission medium must be constant to maintain accuracy. Such systems are not accurate in uncontrolled environments.

[0005] A third type of existing ground clearance sensing system is a magnetic system. These systems are advantageous because they are protected against the ingress of dirt and water. However, existing magnetic ground clearance sensing systems are susceptible to environmental interference and offer a very slow response time for certain applications.

[0006] From DE 10 2013 217 958 A1 a vehicle height sensor with magnetic field scanning with a transmitter and a receiver coil and wireless digital transmission of a height signal is known.

[0007] One object of the present invention is to provide a new and improved system for ground clearance detection that is not susceptible to damage from impact, is protected against disturbances of the line of sight and changes in the medium, and offers fast and accurate measurements with low energy consumption.

[0008] To solve the aforementioned problem, a vehicle with a ground clearance detection system having the features of claim 1 is proposed.

[0009] Advantageous embodiments of the invention are set out in the dependent patent claims. SUMMARY

[0010] Exemplary embodiments provide an improved ground clearance sensing system that offers continuous self-calibration and dead reckoning navigation to improve sensing accuracy and speed. The improved ground clearance sensing system of the present disclosure comprises a coded electromagnetic source as an input unit for a Hall-effect sensor. According to the invention, the improved ground clearance sensing system comprises at least two Hall-effect sensors. The first Hall-effect sensor is configured to receive a signal from the electromagnetic source and is coded to distinguish the coded magnetic field from any magnetic field(s) in the environment. The second Hall-effect sensor is mounted at a fixed distance and orientation relative to the electromagnetic source to provide continuous calibration of the system.In one embodiment, the ground clearance detection system comprises at least two inertial measurement units, such as accelerometers. In this embodiment, a first inertial measurement unit is mounted on the vehicle's body frame, and a second inertial measurement unit is mounted on the vehicle's axle frame. This allows the system to optimize energy consumption by measuring ground clearance more accurately and efficiently at high frequency rates with relatively low energy consumption.

[0011] According to the invention, a bandpass filter is further used to process the signal of the coded electromagnetic data. In addition, several Hall-effect sensors can be used with a single electromagnetic source to provide multi-axis sensing, thus providing robustness in determining changes in ground clearance. Alternatively, in the case of dependent suspensions (rigid axle), a single electromagnetic source can be used to determine the ground clearance at multiple points along the axle.

[0012] Existing magnetic ground clearance sensing systems incorporate an extremely powerful permanent magnet or electromagnet that emits a constant magnetic field, necessitating a limited distance between the magnet and the sensor. Feedback from such systems is slow and can require several seconds for averaging to filter out interfering magnetic fields in the environment. To overcome these problems, the ground clearance sensing system of the present disclosure employs an electromagnetic source capable of switching between high bandwidths to replace the permanent magnet or constant electromagnetic source. The high-bandwidth electromagnetic source is encoded at a specific frequency(ies) to maintain environmental robustness against interfering magnetic fields.In particular, the electromagnetic source of the ground clearance sensing system of the present disclosure is capable of high switching speeds and outputting a magnetic signal at a desired frequency. A frequency bandpass filter is used to extract the coded signal from the measurement of the overall magnetic field. Such a configuration eliminates mechanical connections to the ground clearance sensing, protects it against line-of-sight interference, and ensures a fast and accurate response. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] For a better understanding of the invention, reference is made to embodiments illustrated in the following drawings. The components in the drawings are not necessarily to scale, and related elements may have been omitted to highlight and clearly illustrate the novel features described herein. Furthermore, system components may be arranged in various ways, as is known in the field. In the figures, the same reference numerals may refer to the same parts in all of the different figures, unless otherwise specified. Fig. Figure 1 represents an example of an existing magnetic ground clearance detection system. Fig. Figure 2 is a block diagram comprising components of an embodiment of the ground clearance detection system of the present disclosure. Fig. Figure 3 presents a flowchart of an exemplary process for the operation of the ground clearance detection system of the present disclosure according to one embodiment. Fig. Figure 4 represents an embodiment of the ground clearance detection system of the present disclosure, including multi-axis detection. Fig. 5 presents the exemplary embodiment Fig. 4 for the ground clearance detection system of the present disclosure including multi-axis detection. Fig. Figure 6 is a diagram illustrating an exemplary process of an embodiment of the ground clearance detection system of the present disclosure in operation. Fig. Figure 7 represents an embodiment of the ground clearance detection system of the present disclosure including a self-calibration system. DETAILED DESCRIPTION OF EXAMPLES OF EXECUTION

[0014] Although the coded, electromagnet-based ground clearance sensing system (referred to throughout this description, for the sake of brevity, as the ground clearance sensing system) of the present disclosure can be configured in various forms, only some exemplary and non-limiting embodiments of the ground clearance sensing system are shown in the figures and described in this description. The present disclosure provides an explanation of the ground clearance sensing system and does not limit the ground clearance sensing system to the specific embodiments shown and described. It may not be necessary to include all of the components shown or described, and some embodiments may include additional, different, or fewer components.The arrangement and type of components may vary without deviating from the spirit or scope of the patent claims set forth herein.

[0015] In various embodiments of the present disclosure, an improved ground clearance sensing system for a vehicle is provided, which overcomes many difficulties of existing ground clearance sensing systems. Ground clearance sensing systems measure the distance between a fixed point on the chassis, suspension, or body of a vehicle and the ground. In particular, ground clearance sensing systems for vehicles comprise a plurality of sensors that constantly measure the distance between the vehicle axles and the vehicle body and transmit the measured data to the vehicle's electronic control unit. When the vehicle is loaded and unloaded, the data from the ground clearance sensors changes.These changes are detected by a control unit or electronic control system in the vehicle and provide inputs to the vehicle's suspension systems to modify how the suspension responds to changing road conditions or loads. These suspension modifications can provide a smoother ride on a bumpy road, a lower ride height to improve aerodynamics at high speeds, or a higher ride height for increased ground clearance off-road.

[0016] For example, a first category of ground clearance sensing systems includes spatially connected or coupled systems. Specifically, existing ground clearance sensing systems are potentiometer-based, incorporating a physical connection between an unsprung mass and a sprung mass, and a variable resistance to provide a direct measurement of the difference between these two masses. These systems involve many moving parts and levers and may also include complex linkages for dependent suspensions, such as rigid axles. With so many moving parts, and especially due to the physical connection between the two masses, these systems are susceptible to damage from impacts, which would prevent accurate readings.

[0017] Another non-contact ground clearance measurement system uses ultrasound-based or optical distance measurements. A disadvantage of these systems is that they require a clear line of sight between a reflector and a transmitter, and the transmission medium must be constant to maintain accuracy. Systems using these distance sensing techniques may fail if they lose the line of sight due to significant suspension movement or debris such as mud. These systems are typically used in controlled environments, such as motor racing. Under such conditions, the vehicle's ground clearance system is unlikely to experience external debris or changes in the medium (i.e., dirt or water) that could obstruct the line of sight. However, such systems are not accurate in an uncontrolled environment.

[0018] A third type of existing ground clearance sensing system is a magnetism-based system. Such systems comprise an extremely powerful permanent magnet or electromagnet that emits a constant magnetic signal and a Hall effect sensor that detects a change in the magnetic field to determine a change in a vehicle's ground clearance. These systems are advantageous because they are protected against the ingress of dirt and water. However, existing magnetic ground clearance sensing systems require the magnetic source and the Hall effect sensor to be located close together to eliminate magnetic interference from the environment.

[0019] Fig. Figure 1 represents an embodiment of a ground clearance detection system based on a permanent magnet according to the prior art. As in Fig. As shown in Figure 1, existing ground clearance detection systems based on a magnet comprise a Hall effect sensor 20a, 20b and a magnetic source 18, such as a permanent magnet, which emits a constant magnetic signal, represented by arrow 18a. In this embodiment, the magnetic source 18 is mounted on the vehicle axle 14 between the two rear wheels 16. Fig. Figure 1 shows the vehicle body 12a at a first distance from the rear axle 14 and the vehicle body 12b at a second, greater distance from the rear axle 14. The sensor 20a, 20b, based on the Hall effect, is attached to the vehicle body 12a, 12b.

[0020] In such systems, the distance between the sensor and the magnet must be minimal. This is because the strength of the magnetic field is inversely proportional to the cube of the distance. Regarding Fig. Figure 1 represents the vehicle body 12a at a first distance from the vehicle axis 14, and figure 12b represents the vehicle body at a second, greater distance from the vehicle axis 14. The length of arrow 22a represents the strength of the magnetic field detected by the Hall-effect-based sensor 20a when the vehicle body 12a is at a first distance from the vehicle axis 14. The length of arrow 22b represents the strength of the magnetic field detected by the Hall-effect-based sensor 20b when the vehicle body 12b is at a second distance from the vehicle axis 14. As in Fig. In Figure 1, arrow 22a is longer than arrow 22b, indicating that when the vehicle body 12a is closer to axis 14, the Hall effect sensor detects a higher magnetic field strength than when the vehicle body 12b is further away, even though the strength of the magnetic field 18a emitted by the permanent magnet 18 is the same. In other words, the Hall effect sensor 20a detects a stronger magnetic field 22a at a shorter distance than at a greater distance. Accordingly, the farther the permanent magnet is moved from the sensor, the more energy the sensor must expend to detect magnetic fields. In such systems, the distance between the sensor and the magnetic field source is approximately one inch, and a greater distance would require a strong magnetic force.

[0021] Furthermore, in these systems, a change in ground clearance is determined by a change in the magnetic field detected by the Hall-effect sensor. However, it is understood that other magnetic fields in the environment can interfere with the magnetic field signal from the permanent magnet source. For example, the magnetic field emitted by the Earth or other local disturbances can be detected by the Hall-effect sensors. Thus, in addition to the magnetic field signal emitted by the permanent magnet source, the Hall-effect sensors also detect the magnetic fields in the environment. Accordingly, the permanent magnet used in such systems must be extremely strong to be the dominant local magnetic field, and several seconds may be required for signal averaging to filter out interfering magnetic fields.This is particularly relevant for applications such as the height adjustment of vehicle platforms, where the ground clearance control is closed when feedback from a magnetic field-based sensor is slow. In the system described in this document, the feedback control speed is configured by selecting the coding frequency of the magnetic source, with faster control being achieved primarily through the selection of higher frequencies. The higher the coding frequency, the faster the bandpass filter extracts the coding signal from the overall magnetic field measurement. Thus, the control speed can be adjusted to any desired speed.

[0022] Various embodiments of the present disclosure provide a ground clearance sensing system that overcomes these problems by replacing the permanent magnet source with a frequency-coded electromagnetic source that outputs a magnetic field signal at a defined frequency. The ground clearance sensing system of the present disclosure further comprises a plurality of Hall effect-based sensors that detect a change in magnetic field strength to determine a change in the vehicle's ground clearance. In particular, in certain embodiments, the electromagnetic source is coded based on the signal frequency to maintain robustness against interfering magnetic fields in the environment and to enable the blocking of interfering magnetic fields in the environment.The data received by the Hall-effect-based sensor are filtered to extract the coded signal from the overall measured magnetic field signal in order to provide an accurate measurement of any changes in the coded magnetic field corresponding to changes in ground clearance.

[0023] The ground clearance sensing system of the present disclosure comprises a self-calibration system. In particular, in addition to the coded electromagnetic source and a first Hall-effect sensor, a second Hall-effect sensor is provided. The first Hall-effect sensor is configured to receive a signal from the electromagnetic source and is coded to distinguish the coded magnetic field from any magnetic field(s) in the environment. As described in more detail below, the second Hall-effect sensor is positioned at a defined distance and orientation relative to the electromagnetic source to provide continuous calibration of the system.

[0024] In certain embodiments, the ground clearance sensing system includes an energy optimization system. In particular, in one embodiment, the ground clearance sensing system comprises at least two inertial measuring units. These at least two inertial measuring units are attached to both the vehicle's body frame and its axle frame. As described in more detail below, this enables the system to measure ground clearance more accurately and efficiently at high-frequency speeds with relatively low energy consumption.

[0025] Accordingly, the ground clearance sensing system of the present disclosure requires no mechanical connections. In particular, the ground clearance sensing system of the present disclosure is resistant to impact damage and protected against disturbances of the line of sight and changes in the medium (i.e., water). Therefore, the ground clearance sensing system is capable of providing accurate measurements while submerged in water and when covered with dirt. Furthermore, the ground clearance sensing system of the present disclosure provides a rapid measurement response. That is, the ground clearance sensing system enables features such as adjusting the rear damping after detecting an anomaly at the front wheels. Moreover, to mitigate the difficulties in determining ground clearance for rigid rear axles, the ground clearance sensing system is accurate even under extreme movement.This means that the axis moves in multiple directions, and the ground clearance sensing system of the present disclosure detects this multi-directional movement to determine an accurate reading of the ground clearance. Therefore, the ground clearance sensing system of the present disclosure readily supports applications with dependent suspension (rigid axle).

[0026] Fig. Figure 2 represents an embodiment of the ground clearance sensing system 100 of the present disclosure. Other embodiments of the ground clearance sensing system may have different, fewer, or additional components compared to those described below and in Figure 2. Fig. The two images shown are included.

[0027] The ground clearance sensing system 100 comprises a coded electromagnetic source 118 and one or more sensors 120 that communicate with the controller 110. As described above, the ground clearance sensing system collects data regarding the ground clearance of the vehicle body and transmits the measured data to the vehicle's electronic control unit. If the vehicle load changes or the vehicle's ground clearance changes, the data from the ground clearance sensors change. These changes are registered by the controller 110 and communicated to the vehicle's suspension systems, such as the one in Fig. The active suspension system 130 shown in Figure 2 provides 130 inputs. Each active suspension is assigned to a different wheel of the vehicle. In certain embodiments, each wheel is assigned to an active suspension; while in other embodiments, fewer than all of the wheels are assigned to an active suspension. The active suspensions 130 communicate with the controller 110, and the controller uses the data collected by the ground clearance sensors to change how the suspension responds to changing road conditions or loads.

[0028] The coded electromagnetic source 118 of the present disclosure is capable of high switching speeds; in particular, it can generate and destroy a magnetic field at a defined frequency. The data received by the Hall-effect-based sensors 120 are subsequently filtered to determine the amplitude of the magnetic field at the defined frequency of the electromagnetic source, and any change in the amplitude of the magnetic field occurs due to a change in ground clearance. Accordingly, this source 118 enables the blocking of magnetic fields in the environment and allows for a larger detection range for any given magnetic field strength.

[0029] The ground clearance sensing system 100 comprises a variety of sensors 120. As described above, these sensors 120 include Hall effect sensors for detecting changes in the magnetic field in order to determine changes in ground clearance. A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. With a known magnetic field, the distance from the Hall plate can be determined. In addition to Hall effect sensors, the ground clearance sensing system also includes other types of sensors to obtain data about the environment surrounding the vehicle and about components of the vehicle itself. The sensors 120 transmit the data to a controller 110 for further processing.Such sensors 120 may include, but are not limited to, the following: infrared sensors, cameras or other visual sensors, ultrasonic sensors, RADAR, LIDAR, laser scan sensors, inertial sensors (for example, a suitable inertial measuring unit), wheel speed sensors, road condition sensors (to directly measure certain road conditions), rain sensors, suspension height sensors, steering angle sensors, steering torque sensors, brake pressure sensors, tire pressure sensors and / or a GPS (global positioning system) or other vehicle location or navigation sensor.

[0030] The ground clearance sensing system 100 comprises a controller 110 having at least one processor 112 that communicates with a main memory 114 which stores a group of instructions 116. The processor 112 is designed to communicate with the main memory 114, access the group of instructions 116, and execute the group of instructions 116 to cause the ground clearance sensing system 100 to perform any of the procedures, operations, and features described herein.

[0031] The processor or 112 may be any suitable processing device or group of processing devices, such as, but not limited to, a microprocessor, a microprocessor-based platform, a suitable integrated circuit, or one or more application-specific integrated circuits (ASICs). The main memory 114 may be any suitable storage device, such as, but not limited to, volatile memory (e.g., RAM, which may include non-volatile RAM, magnetic RAM, ferroelectric RAM, and any other suitable forms); non-volatile memory (e.g., disk memory, FLASH memory, EPROMs, EEPROMs, memristor-based non-volatile semiconductor memory, etc.); immutable memory (e.g., EPROMs); or read-only memory.

[0032] Reference is made to Fig. 3, which represents an embodiment of the present disclosure. In particular, it states Fig. Figure 4 represents a vehicle axle 14 between two wheels 16 and a vehicle body 12. A coded electromagnetic source 30 is attached to the axle 14, and a Hall effect-based sensor 31 is attached to the vehicle body 12. Arrow 32 represents the magnetic signal from the coded electromagnetic source 30. Note that arrow 32 is shown as a broken arrow. This is because the magnetic field signal emitted by the coded electromagnetic source is an oscillation signal that is repeatedly switched on and off at a defined frequency. As in Fig. Figure 4 shows that, in addition to the magnetic signal from the coded electromagnetic source, magnetic signals from local disturbances 40, 42, 44 in the environment are also present. Similar to existing technology, in the system and method of the present disclosure, if the source 30 is not located close to the sensor 31, a measurement error would be caused by the surrounding magnetic fields 40, 42, 44. This is because the magnetic field 12 detected by the Hall-effect sensor 31 on the vehicle body is the sum of the local disturbances 40, 42, 44 and the coded magnetic field signal 32.

[0033] Since the ground clearance sensing system of the present disclosure comprises a frequency-coded electromagnetic source, the data received by the Hall-effect sensor can be filtered to obtain the magnetic field signal from the electromagnetic source 30. In particular, the data received by the Hall-effect-based sensor 31, when the source magnetic field 32 is encoded at a certain known frequency, can be bandpass filtered to extract only the data with the frequency of the coded electromagnetic source 30, thereby removing any spurious magnetic content generated by surrounding components or the environment.

[0034] Applying a bandpass filter is a process in which frequencies within a specific range are allowed to pass through, while frequencies outside that range are blocked (attenuated) to reduce ambient noise in the data collected by the Hall-effect sensor. As in Fig. Figure 4 shows that the detected magnetic field is the sum of the local disturbances and the encoded magnetic signal. The desired signal is therefore encoded; it can be filtered out from the entire detected magnetic field.

[0035] It should therefore be noted that, as in Fig. Figure 3 shows that the vehicle body is angled, such that one side of the vehicle body is higher than the other. Therefore, the ground clearance is altered in several directions. Unlike existing systems, which may have multiple sensors to determine the change in ground clearance in different directions, the ground clearance system of this disclosure is a multi-axis system. Multi-axis sensing provides magnetic components that can transmit data over a distance, and in the case of a dependent suspension (rigid axle), over an absolute distance and rotation. The benefit of multi-axis sensing is that a single sensor is required for applications on rigid axles.

[0036] It should be noted that, as in the Fig. 4 and Fig. As shown in Figure 5, the vehicle body 12 is angled and the Hall-effect sensor 31 detects the magnetic fields emitted by the coded signal 32 and the local disturbances 40, 42, 44 in all directions. In particular, as shown in Fig. Figure 3 shows the detected magnetic field, represented by arrows 34a and 34b, as the sum of the local controls and the coded magnetic signal 32. The desired signal is coded and can be filtered out from the total detected magnetic field, as shown by arrows 32a and 32b. Fig. Figure 4 illustrates this. The ground clearance sensing sensor of this disclosure is a multi-axis system, and the magnetic field data received by the Hall-effect sensor can also be filtered to extract the magnitude of the magnetic field along the relevant axes. Multi-axis sensing can selectively detect rotations from changes in distance. This reduces complexity, allowing a single sensor array to be used for applications on rigid axles.

[0037] Furthermore, multi-axis sensing can be used to detect changes in distance in the horizontal direction (where ground clearance would be considered the vertical direction). Changes in horizontal distance would indicate undesirable vehicle behavior, such as vertical wheel oscillation or damage to suspension components. Therefore, a multi-axis ground clearance system can be used to diagnose these conditions.

[0038] Fig. Figure 3 presents a flowchart of an exemplary process or method 200 for operating the ground clearance sensing system of the present disclosure. In various embodiments, a process 200 is represented by a group of instructions stored in one or more memories and executed by one or more processors (such as those mentioned above in connection with Fig. 2 are described) are executed. Although process 200 with respect to the in Fig. As described in the flowchart shown in section 3, many other processes can be used to perform the actions related to process 200. For example, the order of certain blocks shown can be changed, certain blocks shown can be optional, or certain blocks shown may not be executed under certain circumstances.

[0039] When using this embodiment, the ground clearance detection system determines a frequency code for an electromagnetic source, as shown in block 202. Specifically, to compensate for the ambient noise of interfering magnetic fields from the environment surrounding the vehicle, the coded electromagnetic source of this disclosure is coded to output a magnetic signal based on a desired frequency. This magnetic output signal is intended to be read by the Hall-effect-based sensors. The magnetic field data acquired by the Hall-effect-based sensor can be filtered to extract the coded magnetic field signal and to distinguish between the desired magnetic signal and ambient noise. It should be noted that the determined encryption frequency can vary depending on the desired measurement speed.Furthermore, encoding the magnetic source with a fixed frequency allows the use of multiple electromagnetic sources on a single vehicle, with each source being encoded with a unique frequency, thus eliminating the risk of mutual interference between systems. Finally, a single magnetic source can be encoded with multiple frequencies, and the increased complexity makes it difficult for a poor / exogenous detection system to read the ground clearance without precise knowledge of the encryption frequencies (for example, two vehicles equipped with this system driving together or parked close to each other).

[0040] Using the selected encryption frequency, the ground clearance sensing system configures the electromagnetic source to output a magnetic field signal that oscillates at the desired encryption frequency(ies), as illustrated in block 204. As described above, the ground clearance sensing system of this disclosure comprises one or more Hall effect-based sensors to measure any magnetic fields surrounding the sensor. In the embodiments described in this disclosure, the electromagnetic source is mounted on the vehicle axle, and the one or more Hall effect-based sensors are mounted on the underside of the vehicle body. It should be noted that in certain alternative embodiments, the Hall effect sensors may be mounted on the axle, and the electromagnetic source may be mounted on the vehicle body.

[0041] After emitting a magnetic field at the specified frequency, process 200 includes receiving data regarding the magnetic field strength readings from the Hall-effect-based sensors, as illustrated in block 206. As described above, this data from the Hall-effect-based sensors comprises the total detected magnetic field, which is the sum of the coded magnetic signal and any magnetic fields in the environment, such as those from other local disturbances. To obtain an accurate ground clearance measurement, the data from the Hall-effect-based sensor must be filtered to extract only the coded magnetic signal from the coded electromagnetic source.

[0042] The ground clearance sensing system of the present disclosure uses bandpass filtering to extract the amplitude of the encoded magnetic signal, as illustrated in 208. That is, the system of the present disclosure uses a bandpass filter on the sensor data to enable real-time extraction of the amplitude of the magnetic field generated by the electromagnet from the overall detected magnetic field, which may include interference from other magnetic fields generated by other vehicle components or the environment. Bandpass filters typically output a signal or signals at the bandpass frequency, therefore an additional processing step is required to determine the amplitude of the signals at the bandpass frequency.In one embodiment, the bandpass filter can be designed to directly output the signal amplitude at the bandpass frequency without requiring an additional signal processing step. In certain embodiments, after receiving the coded magnetic signal from points at various distances, the system of the present disclosure determines units for spatial distance for the desired ground clearance measurement, as illustrated in block 210. In particular, the system of the present disclosure uses multiple points with known distances between the field source and the sensor to relate the field strength and the spatial distance to each other. The resulting model can then be used to obtain distance measurements directly from the filtered Hall-effect-based sensor.

[0043] By using these units for spatial distance, the system of the present disclosure can be configured to obtain desired ground clearance distance measurements directly from the data of the Hall effect-based sensor, as illustrated in Block 212.

[0044] Fig. Figure 6 presents a graph of the acquired magnetometer raw data from a Hall-effect-based sensor against time and the bandpass-filtered data from the same Hall-effect-based sensor against time for an exemplary embodiment. In this embodiment, the electromagnetic source generates a magnetic field that oscillates at a frequency of 3.5 Hz. In this embodiment, the electromagnetic source is moved several distance points away from the Hall-effect-based sensor, as illustrated in the graphs above.

[0045] First, an initial value is measured at which the electromagnet was switched off. As in Fig. Figure 6 shows that the raw magnetometer reading with the electromagnet switched off was 515 µT. The filtered signal indicates that the signal amplitude at 3.5 Hz is 0 µT. This shows that the filtered reading is also 0 when the electromagnet is off.

[0046] Secondly, the source was moved a second time 25 cm away from the sensor. The raw magnetometer reading fluctuated between 515 µT and approximately 517 µT at a distance of 25 cm between the electromagnet and the Hall-effect-based sensor. The filtered signal indicates that the amplitude of the magnetic field, oscillating at 3.5 Hz, is 2 µT. As described above, the amplitude reading can be converted into units of spatial distance to calculate ground clearance.

[0047] Third, the source was moved a third distance of 5 cm away from the sensor. The raw magnetometer reading fluctuated between approximately 515 µT and 560 µT at a distance of 5 cm between the electromagnet and the Hall-effect-based sensor. The filtered signal shows that the amplitude of the magnetic field at 3.53 Hz is approximately 60 µT. As described above, the amplitude of the filtered signal at the specified frequency (in this case, 3.5 Hz) could be converted into units of spatial distance to determine ground clearance. It should be noted that the strength of the magnetic field is greater at a distance of 5 cm than at a distance of 15 cm, as described above.

[0048] In the last rectangular block at the end of the diagram, the distance between the electromagnetic source and the Hall-effect-based sensor is kept constant, and various disturbances are introduced. These disturbances represent ambient noise from local sources. The disturbances are introduced when the Hall-effect sensor and the electromagnetic source are 10 cm apart. As shown in Fig. Figure 6 shows that the raw magnetometer data includes spikes and a false change in amplitude, indicating that the Hall-effect-based sensor is detecting an increased magnetic field strength during this period. However, the filtered data does not include any such spikes. The filtered data remains unchanged at 3.5 Hz, indicating that the electromagnetic source is stable. Accordingly, as long as the disturbance does not fluctuate at the coding frequency, the filtered signal should not detect any change in field strength. If the electromagnetic source were not encoded, the false jumps in the Hall-effect sensor's raw data would be incorrectly perceived as changes in ground clearance.

[0049] Fig. Figure 7 presents an embodiment of the ground clearance sensing system of the present disclosure, including a self-calibration system. In this embodiment, the ground clearance sensing system uses a second Hall-effect sensor to enable the system to continuously calibrate the ground clearance and thereby account for fluctuations in electrical current, component aging, and variability in component and vehicle level manufacturing.

[0050] In particular, this includes in Fig. Figure 7 shows an embodiment with a coded electromagnetic source 30, which is attached to the axis 14, and a first Hall-effect sensor 31, which is attached to the vehicle body 12 at an unknown distance 50 from the electromagnetic source. Arrow 32 represents the magnetic signal from the coded electromagnetic source 30. Arrow 52 represents the magnetic field detected by the first Hall-effect sensor 31. In this embodiment, a second Hall-effect sensor 54 is attached to the axis 16 at a known distance 56 from the electromagnetic source 30. Arrow 58 represents the magnetic field detected by the attached sensor 54. This second sensor 54 provides an accurate calibration system for the electromagnetic source at a known distance 54.Accordingly, the second Hall effect sensor 54 enables the ground clearance system to constantly calibrate and accurately determine the unknown ground clearance distance 50, instead of using external measurements and calculations to calibrate the system regularly.

[0051] Such a configuration allows the ground clearance detection system to take into account component aging, component-to-component variability, fluctuations in supply current, and variations that occur from vehicle to vehicle.

[0052] Various embodiments of the present disclosure include an energy optimization system. The energy optimization system reduces energy consumption and relaxes the required electromagnetic bandwidth. In particular, it should be noted that the embodiments described above and in the Fig. 3, Fig. 4 and Fig.The embodiments shown in Figure 5 include the encryption of the electromagnetic field at a known frequency. This involves real-time bandpass filtering of the second magnetic field to extract the desired magnetic field strength. For this encryption to be accurate, at least one period of the encryption frequency oscillation must be completed before the amplitude can be extracted and used to determine the ground clearance. Typical bandpass filters usually require several successive periods to ensure the accuracy of the estimated amplitude. Therefore, if the desired speed of the ground clearance measurement increases, the oscillation frequency must also increase, resulting in shorter periods and thus faster ground clearance determination.

[0053] By integrating multiple inertial measuring units, the ground clearance detection system can independently determine the orientation of both the vehicle body and the axle in space with respect to an inertial frame. In particular, in certain embodiments, the ground clearance detection system comprises at least two inertial measuring units, such as accelerometers. In one embodiment, a first accelerometer is arranged on the vehicle body and a second accelerometer is arranged on the vehicle axle. In this embodiment, the initial position of each accelerometer is known. Therefore, the initial distance between the vehicle body frame and the vehicle axle frame is known.By using dead reckoning and the known initial separation of the vehicle body frame from the vehicle axle frame, the ground clearance sensing system can estimate distance data for short periods, thereby reducing the bandwidth at the electromagnetic source. Accordingly, the accelerometer or inertial measurement unit provides the orientation of the body and axle relative to their previously estimated positions, and the ground clearance sensing system can estimate the ground clearance.

[0054] One problem with using dead reckoning navigation is that, even with precise knowledge of the output separation, measurement errors are recorded twice, resulting in a shift in measurements over time. This problem can be solved by using the electromagnetic ground clearance system to estimate the distance between the vehicle body and the axle at the beginning. This energy optimization system can also be reset periodically by connecting the electromagnetic system to the internet to recalculate the vehicle body-axle distance. This provides a new starting point for the dead reckoning navigation and resets the error. The electromagnetic system can then be shut down.

[0055] It is understood that such a design enables the energy-intensive system to be active intermittently, thereby optimizing energy consumption. Each time the electromagnetic system can shut down, the overall energy consumption of the ground clearance detection system is reduced.

[0056] All process descriptions or blocks in the figures are to be understood as representing modules, segments or parts of code comprising one or more execution instructions for implementing certain logical functions or steps in the process, and alternative embodiments are included within the scope of the embodiments described herein, wherein functions may be executed in a different order than that shown or mentioned, including an substantially simultaneous or reverse order, depending on the functionality concerned, which is obvious to the person skilled in the art.

Claims

[1] Vehicle with a ground clearance detection system, comprising: an electromagnetic source (30) designed to output a coded magnetic signal at a specified frequency, wherein the frequency is selected depending on the desired control speed of the ground clearance sensing system, with a higher frequency being selected for a faster control speed; at least two magnetometers (54, 31) designed to acquire magnetic field data, wherein at least one magnetometer (54) is arranged at a defined distance from the electromagnetic source (30); and a controller (110) designed to filter the acquired data using a frequency bandpass filter in order to extract the coded magnetic signal and determine a change in the ground clearance of a vehicle body (12). [2] Vehicle with a ground clearance sensing system according to claim 1, wherein the control uses the at least one magnetometer (54) arranged at the specified distance from the electromagnetic source (30) to calibrate the ground clearance sensing system. [3] Vehicle with the ground clearance detection system according to claim 1, wherein the at least two magnetometers (54, 31) are Hall effect based sensors. [4] Vehicle with the ground clearance detection system according to claim 3, wherein the Hall effect-based sensor (54, 31) is capable of detecting multi-axis magnetic fields. [5] Vehicle with the ground clearance detection system according to claim 1, wherein the controller (110) uses the filtered data to determine units for spatial distance for ground clearance measurements. [6] Vehicle with the ground clearance detection system according to claim 1, wherein the electromagnetic source (30) is capable of high switching speeds. [7] Vehicle with the ground clearance detection system according to claim 1, wherein the control (110) is designed to determine the frequency encryption of the electromagnetic source (30). [8] Vehicle with the ground clearance detection system according to claim 1, wherein the control (110) is designed to dissect a multi-axis reading for magnetic field data with respect to each axis. [9] Vehicle with a ground clearance detection system according to any of the preceding claims, further comprising: a first inertial motion unit with a known starting position on a vehicle body (12); a second inertial motion unit with a known initial position on a vehicle axle (14); and a control unit (110) designed to determine a change in the ground clearance of the vehicle body additionally on the basis of the known initial positions of the inertial motion units. [10] Vehicle with the ground clearance detection system according to claim 9, wherein the control (110) is designed to determine the change in ground clearance of the vehicle body (12) by using dead reckoning navigation and the initial known distance between the vehicle body (12) and the vehicle axle (14). [11] Vehicle with the ground clearance detection system according to claim 9, wherein the first inertial motion unit is an accelerometer. [12] Vehicle with the ground clearance detection system according to claim 9, wherein the control is designed to filter magnetic field data acquired by the magnetometer (54, 31) in order to extract the coded magnetic signal. [13] Vehicle with the ground clearance detection system according to claim 9, wherein the electromagnetic source (30) outputs the coded magnetic signal at a fixed frequency.

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