Ground clearance adjustment on non-horizontal surfaces

Abstract

A vehicle controller of a vehicle is configured to receive instructions to adjust a terrain clearance of the vehicle. In the event that the surface supporting the vehicle does not meet the requirements for flatness and levelness, an amount of air in an air spring of each of a plurality of suspensions of the vehicle is adjusted to achieve a target air quality for each suspension. Where the surface supporting the vehicle meets the requirements for flatness and levelness, the vehicle controller is configured to adjust the amount of air in the air spring of each of the plurality of suspensions of the vehicle to achieve a target output from a terrain clearance sensor of each suspension.

Description

Related Patent Applications

[0001] This application claims the benefit of U.S. Provisional Application Serial No. 63 / 718,505, filed November 8, 2024, entitled “RIDE HEIGHT ADJUSTMENT ON NON-LEVEL SURFACES,” which is hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure relates to adjusting a ride height of a vehicle. SUMMARY

[0003] In one aspect, a vehicle controller is configured to receive instructions to adjust a ride height of a vehicle. The vehicle controller is configured to adjust an amount of air in an air spring of each of a plurality of suspensions of the vehicle to achieve a target air mass in the air spring for each of the suspensions if a surface supporting the vehicle does not meet requirements for flatness and levelness.

[0004] In some embodiments, the vehicle controller is further configured to adjust the amount of air in the air spring of each of the plurality of suspensions to achieve a target output from a ride height sensor of each of the suspensions if the surface supporting the vehicle meets the requirements for flatness and levelness.

[0005] In some embodiments, the vehicle controller is further configured to adjust the ride height to achieve the target air mass in the air spring of each of the plurality of suspensions by, for each of the plurality of suspensions: receiving a ride height measurement from a ride height sensor of each of the suspensions; receiving a pressure measurement of a pressure in the air spring of each of the suspensions; calculating an estimated air mass from the ride height measurement and the pressure measurement; and adjusting the amount of air in the air spring according to the estimated air mass and a target air mass for each of the suspensions.

[0006] In some embodiments, the vehicle controller is further configured to, for each of the plurality of suspensions: calculate a volume of the air spring of each of the suspensions from the ride height measurement; and calculate the estimated air mass from pVn, where p is the pressure measurement, V is the volume, and n is a polytropic constant of air. n

[0007] In some embodiments, the vehicle controller is further configured to: estimate a load of each of the plurality of suspensions; receive a ride height measurement from a ride height sensor of each of the suspensions; receive a pressure measurement of a pressure in the air spring of each of the suspensions; and calculate a target air mass for each of the suspensions from the load, the ride height measurement, and the pressure measurement. ​

[0008] In some embodiments, the requirements on flatness and levelness include an angle of less than 5 degrees. In some embodiments, the requirements on flatness and levelness include a height difference between multiple suspensions of less than 5 centimeters.

[0009] In another aspect, a vehicle includes multiple suspensions, each suspension including an air spring. The vehicle includes a vehicle controller coupled to the air spring of each suspension of the multiple suspensions. The vehicle controller is configured to receive an instruction to adjust a ride height of the vehicle. In a case where a surface supporting the vehicle does not satisfy requirements on flatness and levelness, the vehicle controller is configured to adjust an amount of air in the air spring of each suspension of the multiple suspensions of the vehicle to achieve a target air mass for each suspension.

[0010] In some embodiments, the vehicle controller is further configured to, in a case where the surface supporting the vehicle satisfies the requirements on flatness and levelness, adjust the amount of air in the air spring of each suspension of the multiple suspensions of the vehicle to achieve a target output from a ride height sensor of each suspension.

[0011] In some embodiments, the vehicle further includes one or more pressure sensors configured to sense a pressure in the air spring of each suspension of the multiple suspensions. Each suspension of the multiple suspensions can include a ride height sensor. The vehicle controller is further configured to adjust the ride height to achieve a target air mass in the air spring of each suspension of the multiple suspensions by, for each suspension of the multiple suspensions: receiving a ride height measurement from the ride height sensor of each suspension; receiving a pressure measurement of the pressure in the air spring of each suspension from the one or more pressure sensors; calculating an estimated air mass from the ride height measurement and the pressure measurement; and adjusting the amount of air in the air spring according to a difference between the estimated air mass and the target air mass for each suspension.

[0012] In some embodiments, the vehicle further includes: an air source; an air chamber; a first valve controlling a flow of air from the air source into the air chamber; a second valve controlling a flow of air from the air chamber to an environment of the vehicle; and a plurality of third valves, each third valve controlling a flow of air to or from an air spring of one suspension of the multiple suspensions. The vehicle further includes a vehicle controller configured to add air to the air spring of each suspension of the multiple suspensions by opening the first valve and controlling the third valves of the plurality of third valves that control the flow of air to or from the air spring of each suspension of the multiple suspensions.

[0013] In some embodiments, the vehicle controller is further configured to remove air from the air spring of each of the plurality of suspensions by controlling a third valve of a plurality of third valves of air flow to and from the air spring of each of the plurality of suspensions.

[0014] In some embodiments, the one or more pressure sensors include a pressure sensor configured to sense a pressure within the air chamber, the vehicle controller is further configured to measure the pressure in the air spring of each of the plurality of suspensions by: opening the second valve and controlling a third valve of a plurality of third valves of air flow to and from the air spring of each of the plurality of suspensions; and receiving an output of the pressure sensor.

[0015] In some embodiments, the vehicle controller is further configured to, for each of the plurality of suspensions: calculate a volume of the air spring of each suspension from the ground clearance measurement; and calculate an estimated air mass from pVn, where p is a pressure measurement, V is the volume, and n is a polytropic constant of air.

[0016] In some embodiments, the vehicle further includes one or more pressure sensors configured to sense a pressure in the air spring of each of the plurality of suspensions. Each of the plurality of suspensions includes a ground clearance sensor. The vehicle controller can be further configured to: estimate a load of each of the plurality of suspensions; receive a ground clearance measurement from the ground clearance sensor of each suspension; receive a pressure measurement of the pressure in the air spring of each suspension from the one or more pressure sensors; and calculate a target air mass for each suspension from the load, the ground clearance measurement, and the pressure measurement.

[0017] In some embodiments, the requirements on flatness and levelness include an angle of less than 5 degrees. In some embodiments, the vehicle further includes an inertial measurement unit (IMU), the vehicle configured to sense the angle via the IMU. In some embodiments, the requirements on flatness and levelness include a height difference between the plurality of suspensions of less than 5 centimeters.

[0018] In another aspect, a non-transitory computer-readable medium storing executable code that, when executed by a vehicle controller, causes the vehicle controller to receive an instruction to adjust a ground clearance of a vehicle. In the event that a surface supporting the vehicle does not meet requirements on flatness and levelness, an amount of air in an air spring of each of a plurality of suspensions of the vehicle is adjusted to achieve a target air mass for each suspension.

[0019] In some embodiments, the amount of air in an air spring of each of a plurality of suspensions of a vehicle is adjusted to achieve a target output from a ride height sensor of each suspension in a case where a surface supporting the vehicle meets requirements for flatness and levelness. BRIEF DESCRIPTION OF DRAWINGS

[0020] FIG. 1A An example vehicle is illustrated in accordance with certain embodiments.

[0021] FIG. 1B A chassis of a vehicle is illustrated in accordance with certain embodiments.

[0022] FIG. 2A is a schematic block diagram of a vehicle controller in accordance with certain embodiments.

[0023] FIG. 2B is a schematic block diagram of an alternative embodiment of a vehicle controller in accordance with certain embodiments.

[0024] FIG. 3 Components for controlling ride height of a vehicle are illustrated in accordance with certain embodiments.

[0025] FIG. 4 A method for selecting between different feedback mechanisms when adjusting ride height is illustrated in accordance with certain embodiments.

[0026] FIG. 5 A method for performing feedback control based on estimated air mass is illustrated in accordance with certain embodiments. DETAILED DESCRIPTION

[0027] A vehicle with adjustable ride height is advantageous. A low ride height can be used to facilitate entry into the vehicle or when driving at high speeds on a smooth surface. A high ride height can be useful when driving on rough terrain. When a suspension of a vehicle includes air springs and the vehicle is not on a level and flat surface, adjusting ride height based on a measured ride height of the vehicle can result in adding to the air springs an amount of air that achieves a target ride height when on the surface. However, when the vehicle begins driving on a level and flat surface, the air springs can compress or expand due to a change in load, resulting in the body of the vehicle becoming at an angle with respect to the road. For this reason, existing vehicles prevent ride height adjustment on non-flat and non-level surfaces. Using the methods described herein, adjustment to ride height is achieved by targeting the amount of air within each air spring, such that the body of the vehicle does not become curved when transitioning to a flat and level surface.

[0028] FIG. 1A An example vehicle 100 is illustrated. As FIG. 1AAs shown, vehicle 100 has a plurality of external cameras 102 and one or more front displays 104. Each of these external cameras 102 can capture a specific view or perspective of the exterior of vehicle 100. Images or videos captured by the external cameras 102 can then be displayed on one or more displays in vehicle 100, such as one or more front displays 104, for the driver to view.

[0029] refer to FIG. 1B The vehicle 100 may include a chassis 106, which includes a frame 108 that provides the main structural components of the vehicle 100. The frame 108 may be formed by one or more beams or other structural components, or it may be integrated with the vehicle body (i.e., a monocoque construction).

[0030] In embodiments where vehicle 100 is a battery electric vehicle (BEV) or possibly a hybrid vehicle, a large battery 110 is mounted to the chassis 106 and may occupy a significant portion (e.g., at least 80%) of the area within the frame 108. For example, battery 110 may store 100 to 200 kWh. Battery 110 may be a lithium-ion battery or other types of rechargeable battery. The battery may be substantially planar in shape.

[0031] Power from battery 110 can be supplied to one or more drive units 112. Each drive unit 112 may be formed by an electric motor and possibly a gear reduction drive. In some embodiments, a single drive unit 112 is present, which drives the front or rear wheels of vehicle 100. In another embodiment, two drive units 112 are present, each driving the front or rear wheels of vehicle 100. In yet another embodiment, four drive units 112 are present, each driving one of the four wheels of vehicle 100.

[0032] Power from battery 110 may be supplied to drive unit 112 by one or more sets of power electronics 114. Power electronics 114 may include inverters configured to convert direct current (DC) from battery 110 into alternating current (AC) supplied to the motor of drive unit 112.

[0033] Drive unit 112 is coupled to two or more hubs 116 to which wheels can be mounted. Each hub 116 includes a corresponding brake 118, such as a disc brake as illustrated. Regenerative braking may also be provided by drive unit 112 or other components. Each hub 116 is further coupled to frame 108 via suspension 120. Suspension 120 may include metal or pneumatic springs for absorbing shocks. Suspension 120 may be implemented as a pneumatic or hydraulic suspension capable of adjusting the ground clearance of chassis 106 relative to a support surface. Suspension 120 may include a damper, wherein the characteristics of the damper are fixed or electronically adjustable.

[0034] exist FIG. 1B In the implementation scheme and in the discussion below, vehicle 100 is a battery electric vehicle. However, the systems and methods disclosed herein can be used in any type of vehicle, including vehicles powered by an internal combustion engine (ICE), a hybrid powertrain, a hydrogen fuel cell powertrain, or other types of powertrains that require heating when ready for use, such as a diesel engine.

[0035] FIG. 2A Examples FIG. 1A Example components of vehicle 100. (e.g.) FIG. 2A As shown, vehicle 100 includes a camera 102, one or more front displays 104, a user interface 200, one or more sensors 202, a motion sensor 203, and a positioning system 204. The one or more sensors 202 may include ultrasonic sensors, radio detection and ranging (RADAR) sensors, light detection and ranging (LIDAR) sensors, or other types of sensors. The positioning system 204 may be implemented as a Global Positioning System (GPS) receiver. The user interface 200 allows a user (such as a driver or occupant in vehicle 100) to provide input.

[0036] The components of vehicle 100 may include one or more temperature sensors 205. Temperature sensors 205 may include sensors configured to sense ambient air temperature, battery 110 temperature, power electronics 114 temperature, temperature of each drive unit 112 and / or each motor of each drive unit 112, or the temperature of any other component of vehicle 100.

[0037] The control system 206 executes instructions to perform at least some of the actions or functions of the vehicle 100, including those related to... FIG. 3 to FIG. 5 The functions described. For example, as shown in Figure 2, the control system 206 may include one or more electronic control units (ECUs) configured to perform at least some of the actions or functions of the vehicle 100, including regarding... FIG. 3 to FIG. 5The functions described. In some implementations, each ECU in the ECU is dedicated to a specific set of functions. Each ECU may be a computer system, and each ECU may include the functions described below. FIG. 3 to FIG. 5 The described functionality.

[0038] Some features of the implementation scheme described herein can be controlled by a telematics control module (TCM) ECU. The TCM ECU can provide a wireless vehicle communication gateway to support functionality, as an example and not a limitation, such as over-the-air (OTA) software updates, vehicle-to-Internet communication, vehicle-to-computing device communication, in-vehicle navigation, vehicle-to-vehicle communication, vehicle-to-landscape features (e.g., automatic toll road sensors, automatic toll booths, power distributors at charging stations), or automatic calling functionality.

[0039] Some features of the implementation described herein can be controlled by a Central Gateway Module (CGM) ECU. The CGM ECU serves as the vehicle's communication hub, connecting various ECUs, sensors, cameras, microphones, motors, displays, and other vehicle components, and transmitting data to and from these components. The CGM ECU may include a network switch providing connectivity via a Controller Area Network (CAN) port, a Local Interconnect Network (LIN) port, and an Ethernet port. The CGM ECU can also function as the master controller for different vehicle modes (e.g., road driving mode, parking mode, off-road mode, trailer mode, camping mode), thereby controlling certain vehicle components associated with placing the vehicle in one of these vehicle modes.

[0040] In various implementations, the CGM ECU collects sensor signals from one or more sensors of the vehicle 100. For example, the CGM ECU may collect data from camera 102 and sensor 202. The sensor signals collected by the CGM ECU are then transmitted to the appropriate ECU to perform, for example, actions related to... FIG. 3 to FIG. 5 Describe the operations and functions.

[0041] The control system 206 may also include one or more additional ECUs, as examples and not limitations, such as a Vehicle Dynamics Module (VDM) ECU, an Experience Management Module (XMM) ECU, a Vehicle Entry / Exit System (VAS) ECU, a Near Field Communication (NFC) ECU, a Body Control Module (BCM) ECU, a Seat Control Module (SCM) ECU, a Door Control Module (DCM) ECU, a Rear Zone Control (RZC) ECU, an Autonomous Control Module (ACM) ECU, an Autonomous Safety Module (ASM) ECU, a Driver Monitoring System (DMS) ECU, and / or a Winch Control Module (WCM) ECU. If the vehicle 100 is an electric vehicle, one or more ECUs may provide functionality related to the vehicle's battery pack, such as a Battery Management System (BMS) ECU, a Battery Power Isolation (BPI) ECU, a Balanced Voltage and Temperature (BVT) ECU, and / or a Thermal Management Module (TMM) ECU. In various embodiments, the XMM ECU sends data to the TCM ECU (e.g., via Ethernet, etc.). Additionally or alternatively, the XMM ECU may send other data (e.g., audio data from microphone 208, etc.) to the TCM ECU.

[0042] refer to FIG. 2B In some implementations, the control system 206 may be implemented as a plurality of area controllers 206a, 206b, 206c. Each area controller 206a, 206b, 206c may control a subset of the vehicle's systems. Typically, the subset of systems controlled by each area controller 206a, 206b, 206c may be assigned based on location within the vehicle 100. For example, the western area controller 206a may control the systems on the driver's side of the vehicle 100, the eastern area controller 206b may control the systems on the passenger side of the vehicle 100, and the southern area controller 206c may control the systems in the rear of the vehicle. Each area controller 206a, 206b, 206c may be implemented as a subset of... FIG. 2A This is part of the functionality of the ECU in the control system 206. The functionality of the ECU can be distributed among the area controllers 206a, 206b, and 206c, such that only one area controller 206a, 206b, or 206c implements the functionality of each ECU. Alternatively, the functionality of the ECU can be replicated across multiple area controllers 206a, 206b, and 206c, with each area executing the functionality of the ECU for the portion of the vehicle to which that area controller 206a, 206b, or 206c is assigned.

[0043] Area controllers 206a, 206b, and 206c can be connected to each other via network 206d (such as Ethernet, Controller Area Network (CAN), or other types of networks).

[0044] refer to FIG. 3The control system 206 can control the ground clearance of the vehicle 100 by controlling the operation of the suspension 120. The ground clearance can be controlled based on the output of the ground clearance sensor 300 that senses the current height of each suspension 120. The control system 206 can receive the target ground clearance 302 from the user based on an explicit command to achieve a target ground clearance 302, in response to selecting a driving mode with an associated target ground clearance 302, when starting the vehicle to facilitate entry (kneeling), or in response to some other event.

[0045] As discussed in more detail below, when vehicle 100 is on a non-horizontal and non-flat surface (e.g., an inclined or irregular surface), the adjustment of ground clearance can be handled differently than when vehicle 100 is on a horizontal and flat surface. The orientation of vehicle 100 and the irregularity of the surface supporting vehicle 100 can be detected based on the output of ground clearance sensor 300. Orientation can also be detected based on an inertial measurement unit (IMU) 304 configured to sense acceleration. For example, IMU 304 may include a triaxial or hexaaxial accelerometer configured to detect the acceleration of vehicle 100, including the direction of gravity.

[0046] The suspension 120 may be an air suspension including air springs 306. The air mass within the air springs 306 can be adjusted to change the ground clearance of the vehicle 100. Air chambers 308 can be used to facilitate control of the airflow to the air springs 306. Air chambers 308 may define a volume connected to the air springs 306 via valves 310, each valve 310 controlling the airflow between one air spring 306 and the air chamber 308.

[0047] Air chamber 308 may be further connected to air source 312. Air source 312 may include a compressor. Air source 312 may also include a reservoir for storing compressed air. Air source 312 may include any air source and reservoir known in the art, and may include feedback control that activates the compressor in response to a pressure drop within the reservoir below a set pressure. Valve 314 may control the airflow between air source 312 and air chamber 308.

[0048] Pressure sensor 316 can be configured to detect the pressure within the air chamber and is used to perform feedback control. Exhaust valve 318 can be opened to connect air chamber 308 to ambient air, thereby releasing air into the environment.

[0049] The pressure within the air spring 306 can be measured by opening valve 310, which is connected to and only connected to the air spring 306, while simultaneously closing valve 314 connected to the air source 312 and closing exhaust valve 318. In this configuration, the output of pressure sensor 316 can be used as an estimate of the pressure within the air spring 306.

[0050] The control system 206 can be coupled to and receive outputs from the ground clearance sensor, IMU 304, and pressure sensor 316. The control system 206 is coupled to valves 310, 314, and 318 and controls the opening and closing of valves 310, 314, and 318, such as by methods disclosed herein.

[0051] FIG. 4 A method 400, which can be implemented by control system 206 to control ground clearance, is illustrated. Method 400 may assume that vehicle 100 is stationary or traveling at a low speed (e.g., less than 20 mph). Method 400 may include estimating the current weight distribution of the vehicle at step 402. Step 402 may include estimating the amount of weight on each suspension 120. The weight distribution can be measured by measuring the pressure in each air spring 306 and the ground clearance of each air spring when vehicle 100 is approximately level (e.g., within 5 degrees of the horizontal plane) and deriving the weight distribution from these measurements. The weight on each suspension 120 can be determined according to any method known in the art. Step 404 may be performed periodically. The weight distribution does not change rapidly, so step 404 can be paused once a good weight distribution measurement is obtained during a driving cycle, for example, when the vehicle is stationary on a surface that is approximately level (e.g., within 2 degrees of the horizontal plane).

[0052] Method 400 may include evaluating at step 404 whether an adjustment to ground clearance has been triggered. For example, in response to a change in driving mode, an explicit command from the user, a change in vehicle speed (e.g., driving from a parking position where the vehicle 100 is lowered for easier access), or other triggers.

[0053] If an adjustment to ground clearance has been triggered, method 400 may include assessing at step 406 whether vehicle 100 meets flatness and levelness requirements. For example, step 406 may include assessing whether vehicle 100 is on a horizontal surface (e.g., at an angle of 5, 3, or 2 degrees to the horizontal plane) and on a flat surface (e.g., the height difference between suspensions 120 caused by variations in the support surface is within 5, 3, or 2 centimeters).

[0054] If vehicle 100 is found to be on a flat and level surface as defined above, method 400 may include adjusting the ground clearance at step 408 using feedback from ground clearance sensor 300. Specifically, valves 310, 314 may be used to couple air spring 306 to air source 312 to raise the ground clearance of suspension 120 when the current ground clearance is less than a target ground clearance 302, until the output of ground clearance sensor 300 indicates that the target ground clearance 302 has been achieved. Valves 310, 318 may be used to couple air spring 306 to the environment to lower the ground clearance of suspension 120 when the current ground clearance is higher than the target ground clearance 302, until the output of ground clearance sensor 300 indicates that the target ground clearance 302 has been achieved. Valves 310 may open one at a time during raising or lowering, such as to address unequal weight distribution. When the ground clearance is within a threshold of the target ground clearance (e.g., 20 mm, 10 mm, or 5 mm), feedback control may be used to stop the adjustment. Feedback control based on ground clearance can be performed using any method known in the art.

[0055] If the vehicle is not found to be on a level and flat surface as defined above with respect to step 406, the ground clearance can be adjusted at step 410 using feedback based on the estimated air mass within the air spring 306.

[0056] When the vehicle is on a non-flat and non-level surface, the first load on the suspension 120 will differ from the second load when it is on a flat and level surface. Therefore, when the vehicle is on a non-flat and non-level surface, the ground clearance adjustment will result in the air mass within each air spring 306 corresponding to the first load. When the vehicle 100 transitions to the second load, the ground clearance of the suspension 120 will change in response to the load change, which may result in unequal ground clearance of the suspension 120, potentially persisting for some time until ground clearance-based feedback control induces equilibrium. In existing methods, the vehicle 100 is constrained to a flat and level surface before ground clearance adjustment can be made to avoid this problem. Using air mass-based feedback control, ground clearance adjustment can be achieved over a wider range of surface angles and surface irregularities, while reducing the unequal ground clearance of the suspension 120 upon returning to a flat and level surface.

[0057] FIG. 5 An example of a method 500, which can be implemented by control system 206 to perform feedback control using estimated air mass within each air spring 306, is illustrated. Method 500 can be performed for each air spring 306 (hereinafter simply referred to as "air spring 306") of vehicle 100.

[0058] Method 500 may include calculating the air mass for air spring 306 at step 502. Specifically, for the load on air spring 306 determined by weight distribution, a target ground clearance, the air mass given at the target ground clearance when the vehicle is on a flat and level surface, can be calculated. For example, the manufacturer may provide data relating the ground clearance (e.g., the length of air spring 306) to the volume of air spring 306. The pressure required to support the load on air spring 306 may also be calculated based on a known relationship between load and pressure within air spring 306, for example, load = pressure * area, where the area is the effective area on which the pressure in air spring 306 acts to support the load.

[0059] We can assume pV n = air mass, where p is the pressure required for the air spring 306 to support the load on a flat and horizontal surface, V is the volume of the air spring 306 at the target ground height, and n is a polytropic constant of air. The relationship between air mass, pressure, and volume assumes a constant temperature, which is a valid approximation for vehicle 100.

[0060] Method 500 may include receiving, at step 504, a ground clearance measurement for a suspension 120 including an air spring 306 from a ground clearance sensor 300. Step 504 may include receiving multiple readings from the ground clearance sensor 300 over time, and averaging and / or low-pass filtering the multiple readings to obtain a ground clearance measurement. Various other methods may also be used to remove noise from the ground clearance measurement generated by the acceleration of the vehicle 100.

[0061] Method 500 may include receiving a pressure measurement at step 506, which measures the pressure within the air spring 306. As described above, the pressure measurement may be obtained using a pressure sensor 316 of the air chamber 308. Alternatively, each air spring 306 may have a dedicated pressure sensor for measuring its pressure. Step 504 may include receiving pressure readings from the ground clearance pressure sensor 316 over time and averaging multiple readings to obtain a ground clearance pressure measurement. The pressure readings may also be processed to compensate for vehicle acceleration. For example, according to method 500, the pressure readings over time may be low-pass filtered, with the output of the low-pass filter used as the pressure measurement.

[0062] The method may include calculating the current air quality at step 508, such as based on pV. n = air mass, where p is the pressure measurement from step 506, V is the volume of the air spring corresponding to the ground clearance measurement from step 504, and n is the polyhedral constant of air.

[0063] If it is found at step 510 that the current air quality is lower than the target air quality, then at step 512, air is introduced into the air spring 306, such as by simultaneously opening valves 310 and 314 of the air spring 306 and releasing air from the air source 312 into the air spring 306.

[0064] If the current air quality is found to be higher than the target air quality at step 514, air is released from the air spring 306 at step 516, such as by simultaneously opening valve 310 of the air spring 306 and exhaust valve 318.

[0065] The opening of valves 314 and 318 can be performed in a pulsed manner, with the output of pressure sensor 316 checked between pulses. For example, when air flows into air spring 306, the pressure measurement for air spring 306 can be estimated as the output of pressure sensor 316 minus the calibrated pressure drop. When the flow rate into air spring 306 is very high, pressure measurement can be obtained by pulsed opening of valve 314 when valve 310 leading to air spring 306 is open. Then, when valve 314 is closed, pressure readings using pressure sensor 316 can be obtained between pulses. Similarly, when air is released from air spring 306, the opening of valve 318 can be pulsed, while valve 310 leading to air spring 306 is open. Then, when valve 318 is closed, pressure readings using pressure sensor 316 can be obtained between pulses. Pulsed opening of valves 314 and 318 slows down the rate of ground clearance adjustment to avoid over-adjustment and under-adjustment.

[0066] Method 500 can be repeated from step 504 to achieve or maintain the target air quality. When the vehicle is on a flat and level surface as defined above for step 406, method 500 can end, at which point feedback based on ground clearance measurement can be performed.

[0067] The feedback control loop of steps 504-516 can be executed iteratively for each suspension 120. For example, one suspension 120 can be adjusted one at a time according to method 500 until all suspensions 120 have been adjusted according to method 500. Adjusting one suspension 120 at a time can help prevent suspensions 120 with less load than other suspensions 120 from over-adjusting to the target air mass.

[0068] The air mass in the air spring 306 calculated according to method 500 can be used for other purposes. For example, using a ground clearance measurement, an updated value of the volume V of the air spring 306 can be calculated. This assumes a constant air mass and a relationship between pV. n=Constant, pressure p can be estimated based on the ground clearance measurement and used for various purposes, such as traction control algorithms to estimate instantaneous loads during rock climbing, or other uses. The pressure in air spring 306 calculated based on the ground clearance measurement can be used to charge air chamber 308 before opening valve 310, for example, to ensure that air chamber 308 is higher than the pressure in air spring 306 when air is added to air spring 306 to avoid air loss.

[0069] The air mass in air spring 306 can be used to estimate the leakage of air spring 306. For example, when shut down, the air mass estimated according to method 500 (such as one or more samples of air mass for each air spring 306) can be stored in non-volatile memory. In some embodiments, the air mass estimate is stored only when calculated based on effective pressure and ground clearance samples, for example, when the air mass estimate is calculated based on pressure and ground clearance samples acquired during the operating cycle and no ground clearance adjustment has occurred since the pressure and ground clearance samples were acquired. At startup, samples of air mass can be read from non-volatile memory and used to initialize the air spring pressure model for each air spring 306 and to calculate the air loss value for each air spring 306. If the suspension has sagged significantly since the last operating cycle (e.g., ground clearance decreased) (e.g., >10 mm at any corner), in response, control system 206 can immediately sample the air mass in each air spring 306 to achieve accurate leakage rate calculation and can continue to increase the air mass in each spring 306. If the suspension has not sagged since the last operating cycle, the control system 206 can wait for the trigger sampling until start-up (e.g., speed > 20 km / h) to mask the noise of valve opening and closing.

[0070] Various embodiments of this disclosure have been described for illustrative purposes. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein has been chosen to explain the principles of the embodiments, their practical application, or technical improvements to technologies found in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0071] In the foregoing, reference has been made to the embodiments presented in this disclosure. However, the scope of this disclosure extends beyond the specifically described embodiments. Rather, any combination of features and elements is contemplated for implementing and practicing the contemplated embodiments, whether or not different embodiments are involved. Furthermore, while the embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, the embodiments may achieve some advantages or no particular advantages. Therefore, the aspects, features, embodiments, and advantages discussed herein are merely illustrative.

[0072] The various aspects of this disclosure may take the form of a completely hardware implementation, a completely software implementation (including firmware, resident software, microcode, etc.), or a combination of software and hardware implementations, all of which may be collectively referred to herein as “circuit,” “module,” or “system.”

[0073] Various aspects of this disclosure are described by narrative text, flowcharts, block diagrams of computer systems, and / or block diagrams of machine logic included in implementations of a computer program product (CPP). Regarding any flowchart, depending on the technology involved, operations can be performed in a different order than that shown in a given flowchart. For example, again depending on the technology involved, two operations shown in consecutive flowchart frames can be performed in reverse order, as a single integrated step, concurrently, or in a manner that at least partially overlaps in time.

[0074] A Computer Program Product Implementation (“CPP Implementation” or “CPP”) is a term used in this disclosure to describe any set of one or more storage media (also referred to as “media”) collectively included in a set of one or more storage devices, which collectively include machine-readable code corresponding to instructions and / or data for performing computer operations specified in a given CPP claim. A “storage device” is any tangible device capable of holding and storing instructions for use by one or more computer processing devices. Without limitation, a computer-readable storage medium can be an electronic storage medium, a magnetic storage medium, an optical storage medium, an electromagnetic storage medium, a semiconductor storage medium, a mechanical storage medium, or any suitable combination of the foregoing. Specific types of storage devices including these media include: magnetic disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), compact disc read-only memory (CD-ROM), digital versatile disc (DVD), memory sticks, floppy disks, mechanical encoding devices (such as punched cards or pits / platforms formed in the main surface of the disk), or any suitable combination of the foregoing. As used in this disclosure, computer-readable storage medium refers to a non-transitory storage device rather than the transient signal itself, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides, optical pulses transmitted through fiber optic cables, and electrical signals transmitted through wires and / or other transmitting media. As those skilled in the art will understand, data typically moves at some incidental points in time during the normal operation of the storage device, such as during access, defragmentation, or garbage collection, but the storage device remains non-transitory during these processes because the data remains non-transitory while stored.

Claims

1. A vehicle controller, the vehicle controller being configured to: Receive instructions to adjust the vehicle's ground clearance; and If the surface supporting the vehicle does not meet the requirements for flatness and levelness, the amount of air in the air spring of each of the vehicle's multiple suspensions is adjusted to achieve a target air quality for each suspension.

2. The vehicle controller according to claim 1, wherein the vehicle controller is further configured to: With the surface supporting the vehicle meeting the requirements for flatness and levelness, the amount of air in the air spring of each of the plurality of suspensions of the vehicle is adjusted to achieve the target output from the ground clearance sensor of each suspension.

3. The vehicle controller of claim 1, further configured to adjust the ground clearance to achieve the target air mass in the air springs of each of the plurality of suspensions in such a way as: for each of the plurality of suspensions: Receive ground clearance measurements from the ground clearance sensor of each suspension; Pressure measurements are received from the air springs of each suspension. The estimated air mass is calculated based on the ground height measurement and the pressure measurement. as well as The amount of air in the air spring is adjusted based on the estimated air mass and the target air mass for each suspension.

4. The vehicle controller of claim 3, further configured for each of the plurality of suspensions: The volume of the air spring for each suspension is calculated based on the ground clearance measurement; and According to pV n The estimated air mass is calculated, where p is the pressure measurement, V is the volume, and n is the polyhedral constant of air.

5. The vehicle controller according to claim 1, wherein the vehicle controller is further configured to: Estimate the load on each of the plurality of suspensions; Receive ground clearance measurements from the ground clearance sensor of each suspension; Pressure measurements are received from the air springs of each suspension; and The target air mass for each suspension is calculated based on the load, the ground clearance measurement, and the pressure measurement.

6. The vehicle controller of claim 1, wherein the requirements for flatness and levelness include angles of less than 5 degrees.

7. The vehicle controller of claim 1, wherein the requirements for flatness and levelness include a height difference of less than 5 cm between the plurality of suspensions.

8. A vehicle, said vehicle comprising: Multiple suspensions, each including air springs; as well as A vehicle controller, coupled to the air spring of each of the plurality of suspensions, is configured to: Receive instructions to adjust the vehicle's ground clearance; and If the surface supporting the vehicle does not meet the requirements for flatness and levelness, the amount of air in the air spring of each of the plurality of suspensions of the vehicle is adjusted to achieve a target air quality for each suspension.

9. The vehicle of claim 8, wherein the vehicle controller is further configured to: With the surface supporting the vehicle meeting the requirements for flatness and levelness, the amount of air in the air spring of each of the plurality of suspensions of the vehicle is adjusted to achieve the target output from the ground clearance sensor of each suspension.

10. The vehicle of claim 8, further comprising one or more pressure sensors configured to sense pressure in the air spring of each of the plurality of suspensions; in: Each of the plurality of suspensions includes a ground clearance sensor; and The vehicle controller is further configured to adjust the ground clearance to achieve the target air mass in the air springs of each of the plurality of suspensions in the following manner: for each of the plurality of suspensions: Receive ground clearance measurements from the ground clearance sensor of each suspension; Pressure measurements are received from the one or more pressure sensors from the air springs of each suspension. The estimated air mass is calculated based on the ground height measurement and the pressure measurement. as well as The amount of air in the air spring is adjusted based on the difference between the estimated air mass and the target air mass for each suspension.

11. The vehicle according to claim 10, further comprising: Air source; air chamber; A first valve controls the airflow from the air source to the air chamber; A second valve controls the airflow from the air chamber to the vehicle's environment; Multiple third valves, each third valve controlling the airflow into and out of the air spring of one of the multiple suspensions; and The vehicle controller is further configured to add air to the air spring of each of the plurality of suspensions by opening the first valve and the third valve of the plurality of third valves that control the airflow into and out of the air spring of each of the plurality of suspensions.

12. The vehicle of claim 11, wherein the vehicle controller is further configured to remove air from the air spring of each of the plurality of suspensions by controlling the third valve of the plurality of third valves of the air flow into and out of the air spring of each of the plurality of suspensions.

13. The vehicle of claim 11, wherein the one or more pressure sensors include pressure sensors configured to sense pressure within the air chamber, and the vehicle controller is further configured to measure the pressure in the air spring of each of the plurality of suspensions in such a way as: The third valve of the plurality of third valves that opens the second valve and controls the airflow into and out of the air springs of each of the plurality of suspensions; and Receive the output of the pressure sensor.

14. The vehicle of claim 10, wherein the vehicle controller is further configured to, for each of the plurality of suspensions: The volume of the air spring for each suspension is calculated based on the ground clearance measurement; and The estimated air mass is calculated based on pVn, where p is the pressure measurement, V is the volume, and n is a polynomial constant for air.

15. The vehicle of claim 8, further comprising one or more pressure sensors configured to sense pressure in the air spring of each of the plurality of suspensions; in: Each of the plurality of suspensions includes a ground clearance sensor; and The vehicle controller is further configured to: Estimate the load on each of the plurality of suspensions; Receive ground clearance measurements from the ground clearance sensor of each suspension; Pressure measurements are received from the one or more pressure sensors from the air springs of each suspension; and The target air mass for each suspension is calculated based on the load, the ground clearance measurement, and the pressure measurement.

16. The vehicle of claim 8, wherein the requirements for flatness and levelness include angles of less than 5 degrees.

17. The vehicle of claim 16, further comprising an inertial measurement unit (IMU) configured to sense the angle via the IMU.

18. The vehicle of claim 8, wherein the requirements for flatness and levelness include a height difference of less than 5 cm between the plurality of suspensions.

19. A non-transitory computer-readable medium storing executable code, said executable code causing the vehicle controller, when executed by a vehicle controller, to: Receive instructions to adjust the vehicle's ground clearance; and If the surface supporting the vehicle does not meet the requirements for flatness and levelness, the amount of air in the air spring of each of the vehicle's multiple suspensions is adjusted to achieve a target air quality for each suspension.

20. The non-transitory computer-readable medium of claim 19, wherein the executable code, when executed by the vehicle controller, further causes the vehicle controller to: With the surface supporting the vehicle meeting the requirements for flatness and levelness, the amount of air in the air spring of each of the plurality of suspensions of the vehicle is adjusted to achieve the target output from the ground clearance sensor of each suspension.

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