Integrated vehicle braking system

Abstract

A vehicle control system for a vehicle having a braking system and an active suspension system is provided. The vehicle control system may be configured to adjust a normal component of wheel force at one or more wheels of the vehicle to increase average traction force at the one or more wheels during a braking event. The vehicle control system may adjust the normal component of wheel force at the one or more wheels based on reference road information, forward-looking road information, and / or vehicle sensor data.

Description

Technical Field

[0001] Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application No. 63 / 050,706, filed Jul. 10, 2020, the disclosure of which is hereby incorporated by reference in its entirety.

[0002] Field

[0002] The disclosed embodiments relate to integrated vehicle braking systems, active suspension systems, and related methods of use.

Background Art

[0003] Background

[0003] Conventional vehicle braking systems are designed to reduce the speed of a vehicle or stop the vehicle. Most braking systems apply a retardation torque to one or more of the vehicle's wheels and thus act by causing a longitudinal (e.g., along the direction of vehicle travel) slip in the tire at the point of contact with the ground (e.g., the tire's contact patch). This slip generates a longitudinal force related to the normal load and the coefficient of friction between the tire and the ground.

Summary of the Invention

Means for Solving the Problems

[0004] Summary

[0004] In some embodiments, the vehicle includes a first wheel, a second wheel, a braking system configured to apply braking force to the first wheel and the second wheel, and an active suspension system operably coupled to the first wheel and the second wheel, the active suspension system being configured to apply active force to the first wheel and the second wheel in at least one operating mode to adjust the normal component of the first wheel contact force between the first wheel and the road surface, and to adjust the normal component of the second wheel contact force between the second wheel and the road surface. The vehicle also includes at least one processor configured to control the braking system and the active suspension system. The at least one processor is configured to determine the position of the vehicle, acquire reference road information corresponding to the position of the vehicle, and control the braking system and the active suspension system at least in part based on the acquired reference road information.

[0005]

[0005] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system, wherein the active suspension system is operably coupled to a first wheel and a second wheel, the control method includes determining the position of the vehicle, obtaining reference road information corresponding to the position of the vehicle, and controlling the braking system and the active suspension system at least in part on the obtained reference road information, wherein controlling the active suspension system includes applying active forces to the first wheel and the second wheel to adjust the normal component of the first wheel contact force between the first wheel and the road surface and to adjust the normal component of the second wheel contact force between the second wheel and the road surface.

[0006]

[0006] In some embodiments, the vehicle includes a first wheel, a second wheel, a braking system configured to apply braking force to the first wheel and the second wheel, and an active suspension system operably coupled to the first wheel and the second wheel, wherein the active suspension system is configured to apply active force to the first wheel and the second wheel in at least one operating mode to adjust the normal component of the first wheel contact force between the first wheel and the road surface, and to adjust the normal component of the second wheel contact force between the second wheel and the road surface. The vehicle also includes a forward monitoring sensor configured to sense forward monitoring road information, and at least one processor configured to control the braking system and the active suspension system. The at least one processor is configured to receive forward monitoring road information from the forward monitoring sensor and to control the braking system and the active suspension system at least in part based on the acquired forward monitoring road information.

[0007]

[0007] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system, wherein the active suspension system is operably coupled to a first wheel and a second wheel, the control method includes sensing forward-looking road information with a forward-looking sensor and controlling the braking system and the active suspension system at least in part based on the forward-looking road information, wherein controlling the active suspension system includes applying active forces to the first wheel and the second wheel to adjust the normal component of the first wheel contact force between the first wheel and the road surface and to adjust the normal component of the second wheel contact force between the second wheel and the road surface.

[0008]

[0008] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system includes determining that a braking event is in progress, determining that the braking force request for a first wheel during the braking event exceeds a threshold braking force, and, upon determining that the braking force request exceeds a threshold braking force, adjusting the normal component of the wheel force at one or more wheels of the vehicle by the active suspension system to increase the average traction force at the first wheel during the braking event.

[0009]

[0009] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system includes determining that a braking event is in progress, determining the pitch frequency of the vehicle's pitch vibration, and adjusting the normal component of the wheel force at one or more wheels by the active suspension system to dampen the pitch vibration at the pitch frequency during the braking event.

[0010]

[0010] The concepts described above, and any additional concepts described below, are not limited in this disclosure and can be arranged in any suitable combination. Furthermore, other advantages and novel features of this disclosure will become apparent from the following detailed description of various non-limiting embodiments when considered in conjunction with the accompanying figures.

[0011] Brief explanation of the drawing

[0011] The attached drawings are not intended to be drawn to actual size. In the drawings, identical or nearly identical components shown in various drawings may be represented by similar numbers. For clarity, not all components are labeled in all drawings. [Brief explanation of the drawing]

[0012] [Figure 1]

[0012] This is a block diagram of one embodiment of a vehicle including a vehicle control system and a vehicle output unit for the vehicle control system. [Figure 2]

[0013] It is a schematic diagram of the vehicle in FIG. 1. [Figure 3]

[0014] It is a graph of wheel slip ratio versus longitudinal force for various wheel normal forces according to some exemplary embodiments. [Figure 4A]

[0015] It is a schematic diagram of an embodiment of a vehicle and a road in a first state. [Figure 4B]

[0016] It is a schematic diagram of the vehicle and the road in FIG. 4A in a second state. [Figure 4C]

[0017] It is a schematic diagram of the vehicle and the road in FIG. 4A in a third state. [Figure 5]

[0018] It is a graph of torsional force versus stopping distance applied to a vehicle with an active suspension according to some exemplary embodiments. [Figure 6]

[0019] It is a graph of torsional force versus steering wheel torque applied to a vehicle with an active suspension according to some exemplary embodiments. [Figure 7]

[0020] It is a flowchart according to an embodiment of a method for controlling a vehicle. [Figure 8A]

[0021] It is a schematic diagram of an embodiment of a vehicle and a road in a first state. [Figure 8B]

[0022] It is a schematic diagram of the vehicle and the road in FIG. 8A in a second state. [Figure 8C]

[0023] It is a schematic diagram of the vehicle and the road in FIG. 8A in a third state. [Figure 8D]

[0024] It is a schematic diagram of the vehicle and the road in FIG. 8A in a fourth state. [Figure 9]

[0025] It is a flowchart of another embodiment of a method for controlling a vehicle. [Figure 10]

[0026] It is a flowchart of yet another embodiment of a method for controlling a vehicle. [Figure 11A]

[0027] It is a schematic diagram of an embodiment of a vehicle in the first state. [Figure 11B]

[0028] It is a schematic diagram of the vehicle of FIG. 11A in the second state. [Figure 11C]

[0029] It is a schematic diagram of the vehicle of FIG. 11A in the third state. [Figure 11D]

[0030] It is a schematic diagram of the vehicle of FIG. 11A in the fourth state. [Figure 12]

[0031] It is a flowchart of yet another embodiment of a method for controlling a vehicle.

Mode for Carrying Out the Invention

[0013] Detailed Description of the Invention

[0032] In a conventional automotive system, major subsystems of a vehicle, such as a brake controller or a traction control system, are designed separately and then combined when integrated into the vehicle. Such subsystems may not substantially interact with each other and may not be controlled based on the combined dynamics that affect the individual subsystems. Further, these subsystems may not be controlled based on the combined effects of each subsystem on the dynamics of the entire vehicle. In a conventional automotive system, a brake controller may be solely responsible for vehicle control during a braking event.

[0014]

[0033] In view of the above, the inventors have come to recognize the advantages of a combined vehicle control system that incorporates overall vehicle dynamics due to the presence of strong interactions between automotive subsystems. In particular, the inventors have come to recognize the advantages of a combined vehicle control system that integrates a braking system and an active suspension system to improve average traction and / or vehicle handling during braking events. Furthermore, a combined vehicle control system may be employed to improve traction and handling in situations of low road friction (e.g., caused by road disturbance or road surface conditions).

[0015]

[0034] In some embodiments, a vehicle control system is provided for a vehicle having a braking system and an active suspension system. The braking system may be configured to apply braking force to one or more wheels of the vehicle (e.g., four wheels). The active suspension system may be operably coupled to one or more wheels and may be configured to apply an active force to one or more wheels in at least one operating mode to adjust the normal component of the wheel contact force between one or more wheels and the road surface. The vehicle control system may be configured to control the braking system and the active suspension system in combination to improve the functionality of a single subsystem or both subsystems. In particular, according to the exemplary embodiments described herein, the vehicle control system may employ an active suspension system to improve the functionality of the braking system. In some embodiments, the vehicle control system may improve the average traction of one or more wheels of the vehicle during braking events. As further discussed herein, in some embodiments, the vehicle control system may adjust the normal component of the wheel force at one or more wheels based on reference road information, forward-monitoring road information, and / or vehicle sensor data.

[0016]

[0035] In some embodiments, a vehicle control system may prioritize one subsystem of the vehicle over another subsystem of the vehicle. Thus, one of such subsystems may be assigned as the master controller to achieve minimum functionality even if one or more other subsystems fail or become unavailable. For example, the braking system may be assigned as the master control system. As the master control system, the braking system may rely on other systems, such as the active suspension system, if there is communication that clearly indicates the availability of the other systems. The braking system may be configured to transition to a more conservative fail-safe mode if it does not receive a correct state response from another system, such as the active suspension system. In this way, control of the braking system may take precedence over the active suspension system so that the minimum effectiveness of the braking system can be maintained.

[0017]

[0036] The inventors have recognized that the coefficient of friction μ between a tire and the ground can depend on many factors, including the tire, vehicle speed, and the surface condition of the road. For example, different types of asphalt coatings can have different coefficients of friction. For example, different types of asphalt coatings can have different μ values, and the μ of a given surface or road section can vary significantly depending on environmental conditions, such as rain, snow, mud, and / or ice. The total braking force available to a vehicle in any tire (e.g., longitudinal force in the opposite direction of the vehicle's movement) or lateral force (e.g., lateral force in the direction of the vehicle's turn) is based on the coefficient of friction μ and the normal force acting on the tire. The nature of tire forces is such that the longitudinal force generated during a given longitudinal slip is related to the normal force acting on that tire via a reduction map. That is, the greater the normal force acting on the tire, the greater the longitudinal force, but the increase is not directly proportional. Therefore, the inventors have recognized that, in some cases, a fluctuating normal force load having a given normal force average load may produce less braking or turning force than the same normal force load without fluctuation. According to some embodiments of this specification, a vehicle control system may employ an active suspension system to increase the normal force load of the tires or to reduce fluctuations in the normal force.

[0018]

[0037] The inventors also recognize that during braking or cornering events, a vehicle may decelerate, accelerate, and / or corner. Acceleration of a vehicle can induce inertial forces in the vehicle, which can result in a rollover moment because the vehicle's center of gravity may be on a different plane relative to the tire contact point or patch. This rollover moment may be balanced by differences in normal forces acting on the tires. For example, during braking, the front tires may experience greater normal forces than the rear tires. As another example, during acceleration, the rear tires may experience more normal forces. As yet another example, during cornering, the outer tires experience greater loads. The effect of changing normal forces based on the vehicle's dynamics during deceleration, acceleration, and cornering is referred to herein as load transfer. According to some embodiments herein, a vehicle control system may employ an active suspension system that modifies and otherwise employs load transfer to temporarily increase braking force, increase average braking force, assist cornering, and / or mitigate rollover moments to reduce the likelihood of rollover.

[0019]

[0038] The inventors recognize that any acceleration of the vehicle's sprung mass or unsprung mass in the vertical, pitch, or roll direction can ultimately result in a moment of inertia that can be carried by one or more of the vehicle's tires. Therefore, when the vehicle accelerates downwards, such as when starting on an incline, the normal load on all tires temporarily decreases. This effect is temporary because the average load of the vehicle is equal to the total mass of the vehicle. At the same time, this temporary effect is important in that the normal load can temporarily increase or decrease due to the bouncing of the tires and the vehicle body. As mentioned above, fluctuations in the normal load on the tires can adversely affect the vehicle's behavior because they reduce the vehicle's ability to induce longitudinal and lateral forces. At the same time, the temporary effects of an increase or decrease in normal load can be advantageously utilized if the temporary increase in normal load is properly timed to correspond to a temporary demand for a higher longitudinal force (e.g., braking force). According to some embodiments of this specification, a vehicle control system may employ an active suspension system to temporarily increase the normal force load on the tires to respond to a temporary demand for greater tire force on the road plane. For example, in some embodiments, greater braking force may be desired in emergency stopping situations or during temporary braking events for which the duration of the braking event can be determined. Additional examples of such control and factors for determining when to implement such control are further discussed herein.

[0020]

[0039] The inventors also recognize that vehicles may be equipped with an anti-lock braking system (ABS). An ABS system utilizes the fact that longitudinal tire forces are generally not highest at the maximum slip ratio, but rather peak as tire slip increases and then decrease. Therefore, a sliding tire generates a lower braking force than a less slipping tire, and thus the ABS system prevents the brakes from "locking," thereby allowing the tires to exert a higher overall braking force. Generally, an ABS applies the brakes to allow the tires to slip until a desirable slip ratio is reached, and then releases the brakes so as not to exceed a specific slip value. In this way, the ABS system achieves a greater average braking force during a braking event. However, in some embodiments, the ABS system may pulse the brakes at a braking frequency determined by the desired slip ratio and road conditions. According to some embodiments of this specification, a vehicle control system may employ an active suspension system to increase the temporary normal force load on the tires to accommodate the application of braking by the ABS system. For example, in some embodiments, the active suspension may temporarily increase the normal force load on one or more tires when the brakes are applied and decrease the normal force load when the brakes are not applied.

[0021]

[0040] The inventors also recognize that applying different brakes to one side of a vehicle than to the other side induces a yaw moment in the vehicle. That is, different braking forces on opposite sides of a vehicle generate a yaw moment in the vehicle. Such differences in braking forces may be caused by variations in road conditions between the opposite sides of the vehicle (e.g., ice, puddles, potholes, or other road disturbances). According to some embodiments of this specification, a vehicle control system may employ an active suspension system to increase the normal force load on the tire on the side of the vehicle experiencing a lower braking force. By increasing the normal force load on the tire on the side of the vehicle experiencing a lower braking force, additional braking force may be generated to balance the braking forces and reduce the yaw moment. Thus, vehicle control systems according to the exemplary embodiments described herein may be used to delay the occurrence of rollovers, prevent vehicle oversteer, and reduce yaw induced by braking on surfaces having a certain range of surface friction coefficients.

[0022]

[0041] According to exemplary embodiments described herein, an active suspension system is a suspension system capable of changing the normal force acting on at least one wheel (and tire) of a vehicle by generating a relative force between the sprung mass and the unsprung mass, including the wheel. In some embodiments, the active suspension system may include a hydraulic, electromagnetic, electromechanical, or hydroelectric active suspension actuator. In some embodiments, the active suspension system may include an electric or hydraulic active roll actuator. In some embodiments, the active suspension system may include a semi-active variable damper system, such as a magnetic rheology system or a variable orifice system. Of course, since this disclosure is not so limited, the active suspension system may include any suitable actuators, springs, and / or dampers for adjusting the normal forces applied to the wheels and tires of a vehicle. In some embodiments, the active suspension may have a rapid response time and the ability to generate a dynamic response to an input. Depending on the embodiment, the response time may be less than 50 milliseconds, less than 25 milliseconds, or less than 10 milliseconds to a command for a stepwise change in the applied vertical force (e.g., on the vehicle body), and the response time is defined as the delay from the command for the stepwise change to reaching 90% of the steady-state output. Embodiments disclosed herein provide such capabilities. Furthermore, the active safety suspension system of the present invention can utilize multiple degrees of freedom on the vehicle by using multiple actuators in coordination. In some embodiments, the response of the active suspension system can be precisely tuned to vehicle state parameter information determined by the suspension system or received from other vehicle subsystems (e.g., braking systems such as ABS systems) and directed perpendicular to the road to produce instantaneous or short-duration changes in the timing of the wheel force (e.g., a period of about half the natural frequency of the vehicle body on the main suspension springs).

[0023]

[0042] In some embodiments, the vehicle control system may include one or more driver assistance systems that assist the driver's work, such as steering, braking, or directional and speed control inputs such as acceleration. In some embodiments, the vehicle control system may employ one or more driver assistance systems in the control of the braking system and / or active suspension system. In some embodiments, one or more driver assistance systems may provide information to the braking system and / or active suspension system. For example, in some embodiments, the driver assistance system may provide the vehicle control system with forward-looking road information. Forward-looking road information may include information about approaching road disturbances, information about other vehicles, information about obstacles, information about turns, or any other information. The driver assistance system may include, but is not limited to, an automatic braking system (e.g., reacting to an unseen obstacle), a lane assist system (e.g., keeping the vehicle in the driving lane if no other input is provided), and a blind spot warning system (e.g., warning the driver about a vehicle hidden in a blind spot).

[0024]

[0043] According to exemplary embodiments described herein, a vehicle control system may be operated by one or more processors. One or more processors may be configured to execute computer-readable instructions stored in volatile or non-volatile memory. One or more processors may communicate with one or more actuators associated with various elements of the vehicle (e.g., braking systems, active suspension systems, driver assistance systems, etc.) to control the starting and moving of various elements of the vehicle. One or more processors may receive information from one or more sensors that provide feedback on various elements of the vehicle. For example, one or more processors may receive location information about the vehicle from a Global Positioning System (GPS) or other positioning system. Sensors mounted on the vehicle may include, but are not limited to, wheel rotation speed sensors, inertial measurement units (IMUs), optical sensors (e.g., cameras, LIDAR), radar, suspension position sensors, gyroscopes, etc. In this way, the vehicle control system may implement proportional control, integral control, differential control, a combination thereof (e.g., PID control), or other control strategies for various elements of the vehicle. Other feedback or feedforward control schemes are also contemplated, and this disclosure is not limited in this respect. Any desired number of any suitable sensors may be employed to provide feedback information to one or more processors. Information from the sensors may be employed in conjunction with a desired processing technique (e.g., machine vision). One or more processors may also communicate with other controllers, computers, and / or processors on a local area network, wide area network, or the Internet using a suitable wireless or wired communication protocol. While the exemplary embodiments described herein are described with reference to a single processor, it should be noted that this disclosure is not so limited, and any suitable number of processors may be employed as part of the vehicle.

[0025]

[0044] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system includes determining that a braking event is in progress. In some embodiments, a braking event may be determined when the brakes are applied by the braking system. In some embodiments, a braking event may be determined when a driver assistance device, such as an emergency braking system, is activated. In some embodiments, a braking event may be determined based on the detection of an obstacle or another vehicle in front of the vehicle. The method may include determining that the braking force request to a first wheel during the braking event exceeds a threshold braking force, and, if the braking force request exceeds the threshold braking force, adjusting the normal component of the wheel force at one or more wheels of the vehicle with the active suspension system to increase the average traction force at the first wheel during the braking event. The threshold braking force may be set based on a target longitudinal slip amount of the tire. In some embodiments, the threshold braking force may be set so that the active suspension system increases the normal component of the wheel force before the longitudinal slip of the tire exceeds a value that would cause the ABS system to activate. In some embodiments, the threshold braking force may be set so that the active suspension system is not used during routine braking events for the purpose of increasing the normal component of the wheel force, where the additional braking force generated by the adjusted normal load is not beneficial. By not activating the active suspension system to increase the vertical force during routine braking events, the vehicle's power consumption can be reduced compared to the case where the active suspension system is always activated to increase the vertical force for each braking event. Of course, in some embodiments, the disclosure is not so limited, and the active suspension system may be used for all or almost all braking events for the purpose of increasing the normal component of the wheel force.

[0026]

[0045] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system includes determining that a braking event is in progress. In some embodiments, the determination of a braking event may be based on the application of brakes in the braking system. In some embodiments, the determination of a braking event may be based on the activation of a driver assistance device, such as an emergency braking system. In some embodiments, the determination of a braking event may be based on the detection of an obstacle or other vehicle in front of the vehicle. As mentioned above, load transfer may occur in the vehicle during a braking event. In particular, the normal load may transfer at least partially from the rear wheels to the front wheels during braking. During this transfer, the sprung mass of the vehicle may vibrate in response to the braking force until the vibration is damped by the suspension system. Therefore, in some embodiments, the method may also include determining the pitch frequency of the vehicle's pitch vibration. In some embodiments, determining the pitch frequency may include measuring acceleration data by an inertial monitoring unit (IMU) and / or positional information relating to one or more components of the active suspension. The method may also include adjusting the normal component of the wheel force at one or more wheels using an active suspension system to dampen pitch vibrations at pitch frequencies during braking events. In some embodiments, the adjustment of the normal component of one or more wheels may be employed to dampen fluctuations in the normal load on the front tires. In some embodiments, the adjustment of the normal component of one or more wheels can dampen pitch vibrations of the vehicle's sprung mass.

[0027]

[0046] In addition to the above, the inventors also recognize the advantages of road preview information for controlling braking systems and / or active suspension systems. In some embodiments, a vehicle control system may employ road information in controlling the type and duration of operation of the active suspension system during braking events. The vehicle control system may employ road information from one or more sources, which may allow selection from a variety of control strategies. In some embodiments, the road information may be reference road information obtained from, for example, a cloud service, a server, or another vehicle. For example, in some embodiments, reference road information may be downloaded for a portion of the road surface ahead of the vehicle. Reference road information may be received from another vehicle located ahead of the vehicle from which the information is downloaded. In some embodiments, reference road information may include crowdsourced road conditions. In some embodiments, reference road information may include weather analysis based on local or ultra-local weather maps. In some embodiments, road information may be supplied from one or more forward-looking sensors mounted on the vehicle. For example, such forward-looking sensors may include, but are not limited to, cameras, LiDAR, and radar. The forward-looking sensors may be configured to sense road disturbances and other characteristics of the road surface ahead of the vehicle. Based on the information contained in forward-looking information and / or reference road information, various control strategies may be implemented. For example, different control strategies may be implemented depending on whether the range of the known pattern of the slippery road to be encountered is short or long, whether the slippery road pattern alternates between the left and right sides of the vehicle, or whether the low-friction surface of the slippery road surface is on only one side of the vehicle.

[0028]

[0047] In some embodiments, the vehicle includes a first wheel, a second wheel, a braking system configured to apply braking force to the first and second wheels, and an active suspension system operably coupled to the first and second wheels. The active suspension system may be configured to apply active force to the first and second wheels in at least one operating mode to adjust the normal component of the first wheel contact force between the first wheel and the road surface, and to adjust the normal component of the second wheel contact force between the second wheel and the road surface. The vehicle also includes at least one processor configured to control the braking system and the active suspension system. The at least one processor is configured to determine the vehicle's position, acquire reference road information corresponding to the vehicle's position, and control the braking system and the active suspension system at least in part based on the acquired reference road information. In some embodiments, the at least one processor may determine the vehicle's position based on input from a Global Positioning System (GPS), a Local Positioning System, and / or any other suitable type of positioning system capable of determining the vehicle's position. In some embodiments, reference road information may be obtained from a cloud service. In some embodiments, reference road information may be received from a nearby second vehicle. For example, the nearby second vehicle may be located on the road ahead of the vehicle.

[0029]

[0048] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system, wherein the active suspension system is operably coupled to a first wheel and a second wheel, includes determining the position of the vehicle, obtaining reference road information corresponding to the position of the vehicle, and controlling the braking system and the active suspension system at least in part based on the obtained reference road information, wherein controlling the active suspension system includes applying active forces to the first wheel and the second wheel to adjust the normal component of the first wheel contact force between the first wheel and the road surface, and adjusting the normal component of the second wheel contact force between the second wheel and the road surface. In some embodiments, controlling the active suspension system may include increasing the normal component of the wheel force at the first wheel located at a first corner of the vehicle and the second wheel located at a second opposite corner of the vehicle. In this embodiment, a torsional force may be applied to the vehicle chassis. Such a force may be employed to increase the average normal component load of the front wheel on the side of the vehicle where road surface friction is reduced (e.g., due to puddles, ice formation, snow-covered sections, etc.). Reference road information may include road disturbances that indicate instances of reduced road surface friction or reduced traction due to road surface irregularities, so that the vehicle control system can appropriately apply force to the wheels with the active suspension system. In some embodiments, the first and second wheels may be front wheels, and the method may include adjusting the pitch of the vehicle. In some embodiments, the first and second wheels may be side wheels of the vehicle, and the method may include adjusting the roll of the vehicle. According to such embodiments, the method may include temporarily adjusting the pitch or roll of the vehicle to temporarily increase the normal force load on at least one wheel. In some embodiments, such temporary adjustment may occur over a time period of 0.5 to 1 second, but other time periods may also be used.

[0030]

[0049] In some embodiments, a vehicle control system employing reference road information may rely on a system and method capable of accurate, high-resolution (e.g., equivalent to less than 1 meter resolution in some embodiments) and reproducible positioning of the vehicle. In some embodiments, the vehicle may include GPS to enable vehicle positioning. In some embodiments, the vehicle may employ triangulation using radio signals (e.g., cellular signals). In some embodiments, the vehicle may employ visual recognition of landmarks (e.g., signs, mile markers, etc.) to assist in positioning. In some embodiments, environmental characteristics, including surface characteristics of roads or other terrain (e.g., elevation changes, slopes, embankments, locations of surface extrusions such as bulges and / or depressions, and other surface details), may be used for positioning to identify the vehicle's location (e.g., the vehicle's location on a road), similar to how fingerprints or facial features may be used to identify a person. Such surface-based positioning may, in some implementations, involve detecting a sequence of surface characteristics of the road surface traversed by the vehicle, and then comparing the detected sequence with a sequence of reference surface characteristics stored in a previously generated reference map. The sequence of road surface characteristics may be detected by an active suspension system. For example, feedback from the active suspension system may be used to characterize the vehicle's position based on a previously generated reference map.

[0031]

[0050] In some embodiments, reference road information may be acquired by the vehicle based on its current location. That is, once the vehicle is located, it may download a buffered local map of reference road information relevant to the vehicle at its current location. According to such embodiments, less data may be transferred to the vehicle compared to downloading a global reference map. As the vehicle travels, continuous location tracking may allow the vehicle to buffer additional reference road information in the area surrounding the vehicle. In some embodiments, all reference road information may be downloaded within a predetermined radius of the vehicle. In some embodiments, reference road information may be buffered based on the vehicle's direction of travel. For example, road information for roads already traversed by the vehicle may not be buffered. In some embodiments, reference road information may be generated and shared by multiple vehicles traveling on the road surface. For example, in some embodiments, a vehicle may upload reference road information after passing over the road surface, and the reference road information may be updated for other vehicles subsequently traveling on that road surface. Thus, the reference road information may be dynamic and updated to match the current state of the road surface. In other embodiments, as this disclosure is not so limited, a static map with less frequent updates may be employed.

[0032]

[0051] In some embodiments, the vehicle includes a first wheel, a second wheel, a braking system configured to apply braking force to the first and second wheels, and an active suspension system operably coupled to the first and second wheels, wherein the active suspension system is configured, in at least one operating mode, to apply active force to the first and second wheels to adjust the normal component of the first wheel contact force between the first wheel and the road surface and to adjust the normal component of the second wheel contact force between the second wheel and the road surface. The vehicle also includes a forward-looking sensor configured to sense forward-looking road information and at least one processor configured to control the braking system and the active suspension system. The at least one processor is configured to receive forward-looking road information from the forward-looking sensor and to control the braking system and the active suspension system at least in part based on the obtained forward-looking road information. In some embodiments, the forward-looking sensor may include, but is not limited to, one or more cameras, LIDAR, and radar.

[0033]

[0052] In some embodiments, a method for controlling a vehicle including a braking system and an active suspension system, wherein the active suspension system is operably coupled to a first wheel and a second wheel, includes sensing forward-monitoring road information with a forward-monitoring sensor and controlling the braking system and the active suspension system at least in part based on the forward-monitoring road information, wherein controlling the active suspension system includes applying active forces to the first wheel and the second wheel to adjust the normal component of the first wheel contact force between the first wheel and the road surface and to adjust the normal component of the second wheel contact force between the second wheel and the road surface. In some embodiments, controlling the active suspension system may include increasing the normal component of the wheel force at the first wheel positioned at a first corner of the vehicle and the second wheel positioned at a second opposite corner of the vehicle. In this embodiment, a torsional force may be applied to the vehicle chassis. Such a force may be employed to increase the average normal component load of the front wheel on the vehicle side where road surface friction is reduced (e.g., puddle, ice, snow-covered section, etc.). The forward-monitoring road information may include road disturbances indicating instances of reduced road surface friction so that the vehicle control system can appropriately apply force to the wheels with the active suspension system. In some embodiments, the first and second wheels may be front wheels, and the method may include adjusting the pitch of the vehicle. In some embodiments, the first and second wheels may be side wheels of the vehicle, and the method may include adjusting the roll of the vehicle. According to such embodiments, the method may include temporarily adjusting the pitch or roll of the vehicle to temporarily increase the normal force load on the wheels. In some embodiments, such temporary adjustments may occur over a time period of 0.5 to 1 second or other appropriate time period.

[0034]

[0053] In some embodiments, forward-looking road information may be employed by the vehicle control system to enhance coordination in vehicle handling and safety activities during braking events or other scenarios. Forward-looking information may be supplied from one or more forward-looking sensors. Forward-looking sensors may include vision sensors (e.g., stereo vision cameras), distance measuring systems (e.g., adaptive cruise control radar, sonar, or LiDAR), and any other suitable sensor systems. In some embodiments, the processor may be configured to detect road disturbances based on the forward-looking road information. For example, the processor may detect objects such as other vehicles, pedestrians, or stationary objects and determine their spatial relationship to the vehicle (e.g., distance measuring using stereo vision technology or distance measuring using radar sensors). In some embodiments, the processor may predict the kinematics of the vehicle and objects based on measurements and analyses during braking events, for example.

[0035]

[0054] According to exemplary embodiments of this specification, a vehicle control system may be configured to determine absolute or relative tire friction on the road surface based on feedback from one or more sensors of the vehicle. In some embodiments, tire friction may be determined based on reaching an ABS braking event; that is, friction may be recognized by the vehicle control system when a predetermined wheel slip is reached that causes the ABS system to activate. However, in some cases, the activation level of the ABS system may be reached on one wheel or fewer wheels than the total number of wheels on the vehicle. In such cases, the vehicle control system may recognize that one or more wheels on which the ABS system is not activated have greater tire friction. In some embodiments, the vehicle control system may operate based on this relative difference between the wheels of the vehicle without recognizing the absolute tire friction of each wheel. In other embodiments, the vehicle control system may employ a friction estimator based on tire behavior. The friction estimator may employ wheel torque, wheel speed of the slipped wheel, and measured vehicle speed measured by one or more sensors to estimate the absolute value of tire friction, or the coefficient of friction for a particular tire and road surface. In some embodiments, the vehicle control system may control the braking system and active suspension system based at least in part on the coefficient of friction calculated by a friction estimator. In such embodiments, the vehicle control system may assume that the coefficient of friction may remain the same until the wheel friction changes measurably, and that the coefficient of friction may be updated at the point of change. In some embodiments, the estimated coefficient of friction of the vehicle's wheels may be updated based on reference road information or forward-monitoring road information. For example, if the vehicle control system anticipates encountering ice based on reference road information or forward-monitoring road information, the expected coefficient of friction for controlling the braking system and active suspension system may be reduced.

[0036]

[0055] In one embodiment, a vehicle may encounter a road surface with different coefficients of friction μ on one side compared to the other (referred to as a “split μ” scenario). In some scenarios, the difference in coefficients of friction can be large, for example, μ being 0.7–1.0 on one side of the vehicle and μ being 0.2–0.4 on the other side (e.g., a difference of μ of 0.5 or more). In such scenarios, if a reduction in vehicle speed is desired, the longitudinal tire force (e.g., braking force) achievable on the side with lower surface μ may be lower than that on the side with higher μ. Such a difference in longitudinal tire force can cause a yaw moment that effectively pulls the vehicle toward the surface with higher μ. This can lead to a deviation from the desired vehicle path and may even be sufficient to cause the vehicle to spin out and / or enter a different lane. In some embodiments, the vehicle control system may calculate the yaw metric based on the estimated coefficients of friction on each side of the vehicle. The yaw metric may be, for example, a threshold maximum yaw rate or yaw acceleration, the difference in braking force on each side of the vehicle, the maximum lateral offset from a desired path, or other suitable metrics describing the difference between a desired path on which the vehicle travels and the actual path. In some embodiments, a vehicle control system may determine whether the yaw metric exceeds a threshold (e.g., maximum yaw rate, maximum braking force difference, etc.) and may control the braking system and active suspension system to reduce the yaw metric below the threshold.

[0037]

[0056] In some embodiments where the yaw metric exceeds a threshold, the vehicle control system may apply a vertical force to one or more wheels using an active suspension actuator. In some embodiments, the force may be applied in a torsional pattern over an extended duration, for example, if a split μ scenario persists. In a torsional pattern, the normal load on the two wheels located at opposite corners of the vehicle may be increased. In some embodiments, the vehicle control system may apply more normal force to the front wheels encountering lower μ surfaces, thereby increasing the ability of the corresponding tires to generate longitudinal force. As recognized by the inventors, under certain operating conditions, the front tires may generate more braking force than the rear tires due to the fact that deceleration of the vehicle can release the load on the rear end of the vehicle while simultaneously placing a heavier load on the front of the vehicle. The application of such normal forces may, accordingly, allow the vehicle to increase the total braking force applied during a braking event.

[0038]

[0057] According to exemplary embodiments described herein, if a vehicle is equipped with an active suspension capable of inducing torsional forces in the vehicle and, consequently, the wheels, stability and stopping distance may be improved. In particular, the application of torsional forces as described above improves the symmetry of longitudinal braking forces between the left and right sides of the front axle. In some embodiments, this symmetry can improve stability. Furthermore, due to the symmetry of longitudinal forces, disturbances in steering torque to the driver may be reduced, potentially further improving vehicle stability when the driver is in a loop. Moreover, given fixed stability constraints for a split μ braking scenario with an ABS system having a yaw stability target, the stopping distance in the split μ scenario may be reduced using the torsional force strategy.

[0039]

[0058] Another aspect of this invention relates to modifying longitudinal forces on a vehicle to mitigate undesirable yaw behavior of the vehicle even under normal braking conditions, using forces from an active suspension system that is torsionally positioned such that, for example, two wheels on opposite corners of the vehicle are pushed up and the other two are pushed down substantially simultaneously. As an example, a road crown or rut may generate a lateral gravitational force during a braking event, and a torsional force may be applied using the active suspension to mitigate its effect. This mitigation can occur in two forms—it may attempt to mitigate the effect and reduce the aforementioned metrics such as, for example, peak yaw rate or peak lateral deviation from a desired path, or it may attempt to counteract the perceived behavior by, for example, mitigating the steering torque that occurs during such a scenario. Communication between different systems within the vehicle is a crucial aspect in this scenario, as the braking system, steering system, and active suspension system can all induce yaw and must ideally operate synchronously to determine how they behave.

[0040]

[0059] In some embodiments where the yaw metric exceeds a threshold, the vehicle control system may control the active suspension system to apply force to both tires on the side encountering low μ for a short period of time in a split μ scenario. In such embodiments, the active suspension system may accelerate the vehicle in the roll direction. This roll acceleration may temporarily increase the normal load on the wheels located on the low μ surface, allowing for improved braking performance and reduced yaw metric for a limited period. For example, in some embodiments, such roll acceleration may be generated by the active suspension system for a period of 0.5 to 1.0 seconds or longer. After the application of roll acceleration, the normal force load on the wheels located on the low μ surface may be temporarily reduced, which makes this particular embodiment well-suited to short-time split μ scenarios or scenarios where braking may only be required for a short time. In some embodiments, the vehicle control system may apply roll acceleration to the vehicle based on reference road information or forward-monitoring road information.

[0041]

[0060] An emergency lane change scenario arises when a vehicle needs to be steered from one lane to an adjacent lane at the highest possible speed without spinning or rolling over. This is particularly difficult for vehicles with a high center of gravity, such as trucks and SUVs. Conventional braking systems apply the brakes to deviate the vehicle from a corner if a rollover situation is detected. This can cause the vehicle to slide out of the corner and lose speed. The inventors have recognized that in some embodiments, an active suspension system can be employed in conjunction with the braking system to improve the stability of the vehicle in such scenarios. In some embodiments, the vehicle control system may instruct the active suspension system to lower the vehicle's center of gravity, thus simultaneously mitigating the problems of rollover and tire slip. In some embodiments, the vehicle control system may instruct the active suspension system to apply force to the vehicle's wheels in a manner that reduces the vehicle's roll acceleration and thus reduces the risk of rollover. In some embodiments, the vehicle control system may instruct the active suspension system to apply force in a torsional pattern in a manner that reduces the vehicle's tendency to oversteer.

[0042]

[0061] Similar to emergency lane change scenarios, during handling maneuvers (e.g., aggressive driving), the inventors have recognized that it is beneficial to achieve the highest possible traction in both longitudinal and lateral directions while keeping the vehicle moving in the direction desired by the driver and maintaining the vehicle's understeer target. In conventional vehicles, the stability control system applies braking torque to achieve this objective, resulting in deceleration of the vehicle, which may be undesirable in aggressive driving (e.g., in racing scenarios). In some embodiments, the vehicle control system may use an active suspension system to apply an appropriate amount of torsional force. In some embodiments, the torsional force may be applied so as to distribute the load evenly to the axle having the tire requiring traction. In some embodiments, the cornering load on the front tires during cornering may be reduced (corresponding to moving the vehicle's virtual roll stabilizer to the rear of the vehicle, but doing so by applying active suspension force), and the normal load on that axle may be distributed more evenly, leading to greater lateral force resistance. Similarly, in some embodiments, torsional forces may be used to create a more uniform normal load distribution on the rear axle during acceleration in a rear-wheel-drive vehicle, or a more neutral normal load distribution in a four-wheel-drive vehicle. In some embodiments, the vehicle control system may determine the amount of torsional force to apply by determining the force required to satisfy an understeer objective (generally, "deviating from the turn" may be desired). The application of such torsional force may be equivalent to moving the roll stabilizer to the front of the vehicle, or shifting the roll moment distribution to the front of the vehicle. In some embodiments, the vehicle control system may determine the amount of torsional force to apply by determining the force required to achieve the maximum possible wheel traction. For example, in some embodiments, the vehicle control system may shift the normal load distribution backward at the start of the turn (e.g., during the braking phase), then shift the normal load distribution towards the center of the vehicle at or near the midpoint of the turn, and then shift the normal load distribution forward of the vehicle during the exit from the turn.

[0043]

[0062] According to exemplary embodiments of this specification, if a vehicle encounters a situation while turning and there is a need or desire to decelerate rapidly, the application of braking force may cause the vehicle to slide out of the turning section. In some embodiments, the vehicle control system may modify the application of force by the active suspension system to prioritize assisting the braking system based on warning signals that warn of an imminent or ongoing braking event. For example, in some embodiments, the vehicle control system may apply torsional force to more evenly distribute the load to the wheel (e.g., the front wheel) that is most in need of rapid deceleration in order to maintain the vehicle traveling along its optimal or desired path.

[0044]

[0063] Another scenario may be when a vehicle encounters a bulge large enough to cause the body to vibrate (e.g., pitch vibration) while cornering. These vibrations may persist for several cycles, reducing, then increasing, and then decreasing again the lateral traction force available to the vehicle. In this scenario, since the vehicle is cornering, this can lead to yaw disturbances that can cause the vehicle to move laterally. In some embodiments, the vehicle control system may control the active suspension system to mitigate the acceleration of the vehicle body and reduce the likelihood of such occurrences. In particular, the vehicle control system may control the active suspension system to mitigate vibrations of the normal force that cause fluctuations in the lateral traction force.

[0045]

[0064] In some cases, during a braking event while the vehicle is traveling on a low-μ surface, for example less than 0.5, the following process may occur: (i) first, a high brake torque may be applied; (ii) then, some or all of the wheels may reach a point where the longitudinal force on the corresponding tire peaks, and the tire may begin to slip instead of rolling; (iii) at that point, the braking system may withdraw the brake pressure and reapply the brake torque to a point where the rotation of the tire can be clearly detected again. This process may be repeated during the braking event. Between these repeated applications of braking force and withdrawal of the brake, the tire or wheel may bounce up and down due to, for example, the road surface condition (without necessarily losing contact with the road surface), causing fluctuations in the vertical force, which may cause the braking system to delay the application of braking force compared to a tire without such fluctuations. In some embodiments, the vehicle control system may control the active suspension to temporarily increase the load on the wheels. In some embodiments, the increased load may be timed to coincide with the increase in brake pressure in the braking cycle described above in order to achieve periodically high braking.

[0046]

[0065] In some embodiments, when a reduction in vehicle speed is desired while driving on an uneven road, such as a bumpy road, an active suspension system combined with a braking system can improve achievable braking performance. In such scenarios, road irregularities can excite motion in the vehicle's wheels (e.g., unsprung mass) and body (e.g., sprung mass). In some embodiments, the vehicle control system can reduce fluctuations in the tire force of each tire, thus achieving a higher average longitudinal tire force and resulting in better braking performance (e.g., a shorter stopping distance). In some embodiments, the vehicle control system may employ reference road information and / or forward-monitoring road information to improve the vehicle's braking performance. In some embodiments, the vehicle control system may determine the expected motion frequency of one or more unsprung or sprung masses of the vehicle based on the reference road information and / or forward-monitoring road information. In some embodiments, the vehicle control system may be configured to control the active suspension system to reduce the sprung mass acceleration based on the determined motion frequency. For example, motion at lower frequencies can cause the vehicle control system to dampen the motion of the sprung mass. In some embodiments, the vehicle control system may be configured to control the active suspension system to reduce the unsprung mass acceleration based on a determined motion frequency. For example, motion at a higher frequency than expected may cause the vehicle control system to dampen the motion of the unsprung mass.

[0047]

[0066] During deceleration where ABS intervention is employed, for example, when decelerating by 0.6g or more, the braking system may attempt to generate as much longitudinal force as possible up to the tire's grip limit. As the vehicle decelerates during a braking event, the vehicle body may be rocked forward and backward one or more times (pitch motion). For example, the vehicle may pitch forward, generating a load transfer of normal forces that loads the front tires and lifts the rear tires off the road. Subsequently, the vehicle may pitch backward, lifting the front tires off the road and loading the rear tires. The release of the rear tires can lead to a decrease in vehicle control because the vehicle may lose stability due to the lack of traction on the rear axle. The vehicle may repeat the cycle of loading and releasing the front tires until the vibration is damped by the suspension system. In some embodiments, the brake torque applied by the braking system may be modulated to reduce the pitch motion; however, this may limit the application of brake torque and therefore result in longer stopping distances and lower average deceleration. The inventors have recognized that in some embodiments, a vehicle control system may control an active suspension system to reduce pitch acceleration (for example, by damping pitch vibrations at a specific pitch frequency or range of frequencies). Furthermore, in some embodiments, a vehicle control system may control an active suspension system to dissipate rebound energy when the vehicle is fully bottomed out. This control strategy may result in the application of higher braking force without inducing pitch vibrations, leading to better comfort for the occupants. In some embodiments, a vehicle control system may synchronize the application of pitch force with the frequency of braking force application by a braking system. In some such embodiments, a vehicle control system may determine the pitch frequency of pitch vibrations based on the frequency of braking by a braking system.

[0048]

[0067] In some embodiments, the vehicle's active suspension system may be controlled based on one or more measurement inputs (e.g., from sensors) during braking or cornering events. In some cases, it may be undesirable to control the active suspension in response to all braking and / or cornering events, as the active suspension system may provide little benefit in some minor braking cases at the expense of greater power consumption. In some cases, it may also be undesirable to control the active suspension system in response to major braking and / or cornering events, as such control may reduce the overall braking effect of the vehicle. Therefore, the inventors have recognized that one or more thresholds may be employed to activate and deactivate the active suspension system in response to braking or cornering events. In some embodiments, the vehicle control system may determine during a braking event that the braking force request to a wheel exceeds a threshold braking force. According to such embodiments, if the system determines that the braking force request exceeds a threshold braking force, the system may adjust the normal component of the wheel force at one or more wheels of the vehicle by the active suspension system during the braking event, thereby increasing the average traction force at the first wheel. In some embodiments, the vehicle control system may determine that the braking force request does not exceed a braking force threshold and, in response to the braking event, disable the active suspension system or otherwise fail to operate it.

[0049]

[0068] In some embodiments, the vehicle control system may be configured to determine the size and / or duration of road disturbances from reference road information and / or forward-monitoring road information. The size and / or duration of road disturbances or anomalies can influence the control strategy implemented by the vehicle control system. For example, relatively small road disturbances expected to last less than one second may require a temporary increase in the normal load on the tires by correcting the pitch and / or roll acceleration of the vehicle body. As another example, longer road disturbances expected to last longer than one second may require the application of torsional forces to avoid the generation of pitch or roll moments of the vehicle body. Thus, in some embodiments, the vehicle control system may determine an operating mode based on thresholds for the degree and / or duration of road disturbances. In some embodiments, the degree and / or duration of road disturbances may be used to activate or deactivate the active suspension response when encountering road disturbances for the duration of a braking event. According to some such embodiments, once it is determined whether the degree of disturbance exceeds an activation threshold, the active suspension system may be used to increase the normal component of the wheel force. In response to this, if the degree of disturbance does not exceed the activation threshold during the duration of the braking event, the active suspension system may not respond to such disturbance.

[0050]

[0069] In some embodiments, the vehicle control system may be configured to determine the vehicle motion vibration frequency (e.g., pitch frequency). Depending on the vehicle motion frequency, the vehicle control system may determine whether to dampen the vehicle's unsprung mass or sprung mass. In some embodiments, the characteristics of low-frequency vibrations (e.g., magnitude or energy at frequencies below 10 Hz) may cause the vehicle control system to control the active suspension system to dampen the motion of the vehicle's sprung mass. In some embodiments, high-frequency vibrations (e.g., magnitude or energy at frequencies between approximately 10 Hz and 15 Hz) may cause the vehicle control system to control the active suspension system to dampen the motion of the vehicle's unsprung mass (e.g., wheels). Needless to say, the disclosure is not so limited, and any specific frequency threshold may be employed to determine whether to dampen the vehicle's unsprung mass or sprung mass.

[0051]

[0070] As used herein, an active suspension system is configured to apply an active force between one or more wheels and the vehicle body in at least one operating mode, in addition to applying a resistive force in other operating modes. The active force is applied in the direction of the wheel's movement. This is in contrast to conventional suspension systems that employ a passive damping force that resists the movement of the wheel and / or vehicle body.

[0052]

[0071] As used herein, road disturbance refers to any irregular road condition that a vehicle may encounter while traveling on the road surface. For example, road disturbance may include, but is not limited to, rough pavement, potholes, uneven lanes, variable road materials (e.g., soil, gravel, pavement, concrete, metal, etc.), and road coverings (e.g., snow, ice, salt, sand, soil, water, etc.).

[0053]

[0072] As used herein, a braking event is any process or period of time in which one or more brakes of a vehicle are applied to slow down or stop the vehicle, or the vehicle is slowed down by applying resistance to one or more rotating components in the drivetrain (e.g., during coasting). Since the disclosure is not so limited, a braking event may have any duration. In some embodiments, since the disclosure is not so limited, a braking event may include a single application of a brake or multiple applications of a brake.

[0054]

[0073] Looking at the figures, certain non-limiting embodiments are described in more detail. Since this disclosure is not limited to the specific embodiments described herein, it should be understood that the various systems, components, features, and methods described in relation to these embodiments may be used individually and / or in any desired combination.

[0055]

[0074] Figure 1 is an exemplary block diagram of one embodiment of a vehicle 100 including a vehicle control system 102 and a vehicle output unit 120 for the vehicle control system. The vehicle control system may include at least one processor configured to execute computer-readable instructions and control the vehicle output unit 120. As shown in Figure 1, the vehicle control system may include an electronic stability control system 104 and an anti-lock braking system (ABS 106). The electronic stability control system may be configured to automatically apply the brakes to help the driver steer the vehicle to an intended location when traction is lost. As previously mentioned, the ABS is configured to prevent the wheels from locking and skidding. As shown in Figure 1, the vehicle control system may include a forward-looking sensor 108. The forward-looking sensor may sense road characteristics, road disturbances, or objects in front of the vehicle and may be provided to at least one processor as forward-looking road information. In the embodiment of Figure 1, the vehicle control system may also include reference road information 110, which may be stored in a memory mounted on the vehicle control system. In some embodiments, as shown in Figure 1, the vehicle control system may also include a transceiver 112 configured to transmit or receive information. In some embodiments, the transceiver 112 may be configured to receive reference road information from other vehicles or cloud services (e.g., one or more servers). The disclosure is not so limited, and the transceiver may be configured to communicate wirelessly over any suitable wireless protocol.

[0056]

[0075] As shown in Figure 1, the vehicle may include a plurality of vehicle output units 120 controlled by a vehicle control system. In particular, the vehicle output units may include a throttle 122 (which may include a throttle for the engine or electric motor), a steering module 124, an active suspension system 126, a braking system 128, and other output units 130. The vehicle control system may be configured to control these vehicle output units individually or in various combinations. By controlling various vehicle output units in combination, the vehicle control system may provide improved stability and braking force compared to a vehicle in which each system is controlled independently. In some embodiments, the vehicle control system may prioritize certain outputs. For example, the braking system may be prioritized over the steering or active suspension system. Thus, a system that is more important to a given scenario may be prioritized for control, with possible assistance from other vehicle output units. The operating modes and control schemes of the vehicle output units are described further below.

[0057]

[0076] In some embodiments, as shown in Figure 1, the vehicle may include a real-time bidirectional communication system 140 that enables communication between various subsystems and the vehicle output unit. The communication system may employ any suitable connection protocol, such as a Controller Area Network (CAN), Local Interconnect Network (LIN), Vehicle Area Network (VAN), FlexRay, D2B, Ethernet, Direct Communication Link (such as wire or optical fiber), or Wireless Communication Link. The communication system may be used to share information between subsystems such as ABS or ESC, while receiving vehicle state parameters or other information from these same or other systems. Information that may be shared between subsystems and used for vehicle output control may include, but is not limited to, vehicle yaw and yaw rate, vehicle speed, vehicle acceleration, vehicle lateral acceleration, steering wheel position, steering wheel torque, (if braking is applied), and suspension spring compression. The vehicle control system may control the active suspension system 126 based on information from the vehicle, such as the state of one or more vehicle subsystems, such as ABS 106 and ESC 104, which engage during abnormal events. For example, the system may provide different controls for the wheels and the vehicle when one or more systems are engaged.

[0058]

[0077] In addition to the above, in some embodiments, the active suspension system 126 may sense several parameters related to the movement of the road, wheels, and vehicle body, as well as other parameters that may be beneficial to other vehicle subsystems. Such information may be transmitted from the active suspension system to other subsystems via the communication system 140. Other vehicle subsystems may modify their control based on the information from the active suspension system. Thus, bidirectional information may be transmitted between the active safety suspension system and other subsystems, and control of both the active suspension system and other vehicle systems may be provided at least in part based on this information transmission. For example, the application of the brakes of the braking system 128 by ABS 106 may be synchronized with the increase in wheel force by the active suspension system on one or more wheels.

[0059]

[0078] Figure 2 is a schematic diagram of the vehicle 100 of Figure 1. As shown in Figure 2, the vehicle includes a vehicle control system 102 that can communicate with various subsystems via a communication system 140. As shown in Figure 2, the vehicle includes an active suspension system 126 operably coupled to the vehicle's wheels 150. In particular, the actuators of the active suspension may be operably interposed between each wheel of the vehicle and the vehicle body so that separate actuators of the active suspension can independently control separate wheels of the vehicle. The vehicle may also include a braking system 128. The braking system may include independent brakes coupled to each of the vehicle's wheels 150 so that braking force can be applied independently to each wheel. According to the embodiment of Figure 2, the vehicle may also include a forward-looking sensor 108. The forward-looking sensor 108 may be at least one camera, LIDAR, radar, or a combination thereof that can be configured to sense forward-looking road information that can be employed by the vehicle control system 102.

[0060]

[0079] As shown in Figure 2, a vehicle may traverse a road 200. The road may include one or more road disturbances 202. Road disturbances 202 may cause fluctuations in the vertical load on the vehicle's wheels 150 (for example, by accelerating the wheels upward and / or downward). In some embodiments, road disturbances may reduce the effective coefficient of friction between the wheels 150 and the road 200.

[0061]

[0080] Figure 3 is a graph of wheel slip ratio versus longitudinal force with respect to normal force for various wheels, according to some exemplary embodiments of this specification. As discussed earlier, the longitudinal force of a tire is a function of the slip ratio, which is a measure of the tire's rotational speed relative to the free rotational speed. The longitudinal force of a tire increases with increasing slip ratio up to a certain point, then peaks, and then decreases. To maximize braking force, the ABS system and vehicle control system may control the vehicle to target the peak value of the longitudinal force. As shown in Figure 3, the greater the normal force of the tire, the greater the maximum longitudinal force that can be generated, and the greater the slip ratio at which that peak force is achieved. Therefore, in some scenarios, increasing the normal force of a tire can significantly improve the vehicle's ability to generate braking force with that tire.

[0062]

[0081] Figure 4A is a schematic diagram of an exemplary embodiment of a vehicle 100 and a road 200 in a first state. As shown in the schematic diagram of Figure 4A, the vehicle includes a first wheel 150a (e.g., left front wheel), a second wheel 150b (e.g., right front wheel), a third wheel 150c (e.g., left rear wheel), and a fourth wheel 150d (e.g., right rear wheel). The wheel sizes shown in Figures 4A-4C represent the normal component of the wheel force at each wheel. As shown in Figure 4A, the vehicle is in a steady state, and the normal components are balanced accordingly and approximately equal to each other. The vehicle includes an active suspension system which may be configured to independently adjust the normal component of the wheel force at each wheel.

[0063]

[0082] As shown in Figure 4A, the road 200 includes multiple road disturbances 202. The road disturbances in Figure 4A may be road surfaces having lower friction than the reference road surface. In the embodiment of Figure 4A, the road disturbances create a split μ scenario in which the coefficient of friction between the tires on different sides of the vehicle and the road surface is different. In the state shown in Figure 4A, the vehicle is about to be braked at the braking start line 204. The road disturbances begin at line 206. The exemplary road disturbances in Figure 4A are arranged in a checkerboard pattern, which can be particularly difficult for a conventional vehicle to handle during braking. As previously mentioned, a yaw moment may be introduced to the vehicle due to the reduction in tire friction on one side of the vehicle. This yaw moment can be compensated through the application of torsional forces, as will be further considered with reference to Figures 4A-4C.

[0064]

[0083] Figure 4B is a schematic diagram of the vehicle 100 and the road in Figure 4A in the second state. As shown in Figure 4B, the vehicle has begun to brake. First, due to load transfer, the normal load moves away from the rear wheels 150c and 150d and to the front wheels 150a and 150d. As shown in Figure 4B, the size of the third wheel 150c and the fourth wheel 150d is smaller than in Figure 4A, indicating a difference in normal force. In Figure 4B, the first wheel 150a encounters road disturbance 202. As mentioned above, the coefficient of friction between the first wheel and the road 200 may be lower than that of wheel 150b due to the disturbance 202 (for example, the road disturbance may be an ice patch). In conventional vehicles, the first wheel cannot generate the same longitudinal force, so the braking force will be lower on the first wheel 150a compared to the second wheel 150b. However, in the vehicle shown in Figure 4B, the active suspension system can be controlled to compensate for the difference in braking force on both sides of the vehicle. In particular, the filled-in wheels shown in Figure 4B indicate wheels on which the active suspension applies a downward force (for example, increasing the normal load on the wheel). Therefore, as shown in Figure 4B, the normal load on the first wheel 150a and the fourth wheel 150d is increased by the active suspension (for example, a torsional force is applied to the vehicle). As the normal loads on the first wheel 150a and the fourth wheel 150d increase, the normal loads on the second wheel 150b and the third wheel 150c decrease accordingly. As a result, the normal load on the first wheel 150a is the largest due to the combination of load transfer and torsional force applied to the vehicle. Also, the normal load on the first wheel 150a is greater than the normal load on the second wheel 150b. This difference in normal load between the front wheels allows for the generation of additional braking force on the first wheel 150a, thereby reducing the yaw moment caused by road disturbances 202. As shown in Figure 4B, the normal load of the fourth wheel 150d is also greater than that of the third wheel 150c.

[0065]

[0084] In some embodiments, when wheel slip is detected, the vehicle 100 may apply the torsional pattern shown in Figure 4B. For example, the ABS system may be activated during a braking event when the first wheel 150a encounters a road disturbance 202. Thus, the application of the torsional force may be responsive. In some embodiments, the vehicle may determine that one of the front wheels is slipping more than the other (for example, the first wheel 150a is slipping more than the second wheel 150b). Once a difference in wheel slip on two sides of the vehicle is determined, a torsional force may be applied to the vehicle by the active suspension system. In some embodiments, the vehicle may determine the absolute value of wheel slip for the wheels of the vehicle based on wheel torque, wheel speed, and vehicle speed. If the wheel slip of one wheel exceeds a threshold, a torsional force may be applied to increase the normal force load on that wheel.

[0066]

[0085] In some embodiments, the vehicle 100 may apply a torsional pattern, at least partially shown in Figure 4B, based on reference road information and / or forward-monitoring road information (e.g., from a forward-monitoring sensor). For example, the vehicle 100 may predict road disturbances 202 based on minor road information and control the braking system and active suspension system accordingly. In some such embodiments, the normal force loads on the first wheel 150a and the fourth wheel 150d may be adjusted before the first wheel reaches line 206. In this way, the vehicle may prepare for road disturbances to reduce their impact on the vehicle's dynamics. In some embodiments, reference road information or forward-monitoring road information may be used to apply a temporary increase in normal force loads to the wheels without applying torsional forces. For example, if the road disturbance 202 may have a size such that the suspension response can be applied for a duration of less than one second, the active suspension system may increase the normal force loads on a single wheel or two wheels that encounter the disturbance. For example, the normal force load of the first wheel 150 may be increased without increasing the normal force load of the fourth wheel 150d. Such an arrangement may impart acceleration to the body of the vehicle 100 and may be disadvantageous when the road disturbance is longer. Therefore, reference road information and / or forward-monitoring road information may be used to determine whether the magnitude of the road disturbance exceeds a road disturbance threshold, so that the vehicle's suspension can be controlled appropriately.

[0067]

[0086] Figure 4C is a schematic diagram of the vehicle 100 and road 200 in Figure 4A in the third state. As shown in Figure 4C, the vehicle is moving forward along the road 200 while continuing the braking event that started at line 204 shown in Figure 4A. However, the wheels experiencing reduced road surface friction due to the road disturbance are different from the wheels shown in Figure 4B. Therefore, the torsional force applied to the vehicle 100 is adjusted. As shown in Figure 4C, the second wheel 150b, like the third wheel 150c, is located on the road disturbance 202. Therefore, the active suspension system may be used to increase the normal force load on the second and third wheels, as shown in Figure 4C. By increasing the normal load on these wheels, the difference in braking force occurring on each side of the vehicle is compensated for, thereby reducing yaw motion. In some embodiments, a torsional force may be applied during the braking event based on which of the front wheels of the vehicle has greater wheel slip. Thus, depending on the road 200, the applied torsional force may be changed to the front or rear based on where an additional normal force is most beneficial in reducing the vehicle's yaw moment during braking.

[0068]

[0087] In some embodiments, the application of forces to the active suspension as described in Figures 4A-C may be reversed. For example, the active suspension may increase the normal force on the front wheel experiencing higher friction (e.g., the second wheel 150b in Figure 4B) to maximize the total braking force. This application of forces to the active suspension may result in an increase in yaw disturbance imparted to the vehicle, but may also result in an increase in braking force on the front wheel with the highest traction. In some embodiments, this strategy may be used in conjunction with a steering system by commanding an appropriate steering moment from the steering module 124 to mitigate any additional yaw disturbance. In some embodiments, a strategy of balancing the braking force on both sides of the vehicle or maximizing the braking force on one side may be determined by the vehicle control system based on information from vehicle sensors and / or approaching road information, such as information on the degree and magnitude of road events and information on the criticality of the braking situation (for example, if the vehicle is about to collide with another vehicle in front of it, a strategy of maximizing braking at the expense of possible yaw disturbance may be employed, or for example, if the road is narrow but no obstacle is detected ahead, a strategy of minimizing yaw disturbance may be employed).

[0069]

[0088] Figure 5 is a graph of torsional force versus stopping distance applied to vehicles with active suspension in several exemplary embodiments. In particular, the graph in Figure 5 shows the stopping distance based on the amount of torsion applied in the scenarios depicted in the exemplary embodiments of Figures 4A-4C. As shown in Figure 5, the stopping distance decreases as the application of torsional force increases. As mentioned above, the application of torsional force allows for the generation of additional braking force on wheels in contact with low-μ surfaces.

[0070]

[0089] Figure 6 is a graph of torsional force versus steering wheel torque applied to a vehicle with active suspension in several exemplary embodiments. In particular, the graph in Figure 6 shows the steering wheel torque based on the amount of torsion applied in the scenarios depicted in the exemplary embodiments of Figures 4A–4C. The wheel torque in Figure 6 shows the yaw moment generated by the split μ scenario. As shown in Figure 6, the steering wheel torque decreases as the application of torsional force increases. As mentioned above, the application of torsional force allows for the generation of additional braking force in the wheel where friction would otherwise decrease, reducing the mismatch between the braking forces on opposite sides of the vehicle. In some embodiments, this can also reduce disturbances applied to the steering wheel and, consequently, to the driver.

[0071]

[0090] Figure 7 is a flowchart of one embodiment of a method for controlling a vehicle. In block 300, it is determined whether a braking event is in progress. Determining whether a braking event is in progress may include detecting the application of brakes by the user or other vehicle systems. In block 302, a braking force request exceeding a threshold braking force is determined. A braking force request may exceed the threshold braking force, for example, when the wheel encounters road disturbance, which may result in a decrease in the braking force of the wheel. In an optional block 304, wheel slip may be detected during a braking event. For example, ABS may be activated during a braking event. In some embodiments, a friction estimator may be employed to estimate the absolute value of friction based on relative wheel slip, and this friction estimator may be employed to control an active suspension system. In some embodiments, wheel slip may be estimated based on a comparison of wheel rotation with expected rotation based on vehicle speed. In block 306, the normal component of the wheel force at the wheel is adjusted by the active suspension system to increase wheel traction. In some embodiments, the adjustment may include increasing the normal load on the wheel. In some embodiments, the adjustment may be based on detected wheel slip. In optional block 308, the normal component of the force on the first wheel is adjusted in the active suspension system to increase the traction of the first wheel. In optional block 310, it is determined whether the overall braking force requirement exceeds an overall threshold. If the overall braking force exceeds the threshold, the response of the active suspension system to the braking event may be temporarily disabled (e.g., during the braking event). Such an arrangement may be desirable in situations where the overall braking force is reduced by adjusting the normal component of the wheel.

[0072]

[0091] Figures 8A–8D show schematic side views of another embodiment of a vehicle 100 employing an active suspension system to improve braking system performance during braking events. As shown in Figure 8A, the vehicle 100 includes a forward-looking sensor 108 configured to sense forward-looking road information and provide that information to the vehicle control system. Similar to the scenarios in Figures 4A–4C, the scenarios in Figures 8A–8D include a braking event beginning at line 204. The vehicle is traveling on road 200 which includes road disturbances. In the scenarios in Figures 8A–8D, the road disturbances do not create a split μ scenario, but rather induce a loss of road friction on both sides of the vehicle. The road disturbances 202 begin at line 206 and end at line 208. The road disturbances in Figures 8A–8D may be ice formations, potholes, puddles, or other road disturbances. However, the road disturbances in Figures 8A-8D are small in size, which means that the suspension response of the active suspension of vehicle 100 may be temporary, as will be further discussed below. In the embodiments of Figures 8A-8D, arrow 151 is shown to indicate the normal force load on the front axle of the vehicle.

[0073]

[0092] Figure 8B is a schematic diagram of the vehicle 100 and road 200 in Figure 8A in the second state. As shown in Figure 8B, the vehicle begins a braking event after crossing line 204. As a result of the braking force applied to the front wheels 150b and rear wheels 150d, the load transfer causes the normal force load to move from the rear axle connected to the rear wheels 150d to the front axle connected to the front wheels 150b. As shown in Figure 8B, as a result the vehicle 100 tilts forward. Therefore, compared to the state in Figure 8A, the normal force load increases as indicated by arrow 151. In some embodiments, as described above, the active suspension of the vehicle may be operated to dampen the pitch vibrations associated with this pitching motion of the vehicle and reduce the fluctuations in the normal load on the vehicle wheels.

[0074]

[0093] According to embodiments of Figures 8A-8D, the forward monitoring sensor 108 may detect road disturbances before the vehicle reaches them. The vehicle control system of the vehicle 100 may determine the magnitude of the road disturbance and prepare an active suspension response to compensate for the loss of braking force caused by the road disturbance. In some embodiments, road disturbances may also be included in reference road information that may be mounted on the vehicle. According to embodiments of Figures 8A-8D, the road disturbance 202 is relatively small, meaning that the vehicle can pass over the road disturbance in less than one second. To compensate for the loss of braking force when the vehicle crosses the road disturbance, the active suspension system may apply pitch acceleration to the vehicle to temporarily increase the normal load on the vehicle's front axle, as shown in Figure 8C. Such a temporary increase in normal load may not be applied if the road disturbance is larger.

[0075]

[0094] Figure 8C is a schematic diagram of the vehicle 100 and road 200 in Figure 8A in the third state. As shown in Figure 8C, the active suspension of the vehicle 100 pushes the front end of the vehicle upward, and correspondingly increases the load on the front wheel 150b, as indicated by arrow 151 relative to Figure 8B. Since the acceleration applied to the vehicle is temporary, the increase in normal load is also temporary. Therefore, the active suspension may refrain from applying such acceleration until the front wheel 150b reaches the start line 206 of the road disturbance 202. The increased normal force may maintain braking force through the road disturbance. In some embodiments, a forward-looking sensor 108 may provide information about the positions of the start line 206 and the end line 208 so that the active suspension can be controlled accordingly.

[0076]

[0095] Figure 8D is a schematic diagram of the vehicle 100 and road 200 in Figure 8A in the fourth state. As shown in Figure 8D, once the temporary acceleration of the vehicle 100 is complete and the vehicle has passed at least partially over the road disturbance 202, the vehicle may return to a forward-leaning posture. Therefore, the normal force load may also return to the normal force load shown in Figure 8B. Of course, during the transition from the increased normal force load back to the original normal force load, the normal force load may be temporarily reduced, and the vehicle body accelerates back towards the front wheels 150b. However, since the front wheels 150b are no longer located over the road disturbance 202, this temporary reduction in normal force may have virtually no effect on the braking force.

[0077]

[0096] Figure 9 is a flowchart of another embodiment of a method for controlling a vehicle. In block 400, forward monitoring road information is sensed by a forward monitoring sensor. In block 402, road disturbances are identified based on the forward monitoring road information. For example, at least one processor may employ image processing techniques and / or machine learning to determine the presence of road disturbances, as well as one or more characteristics of the road disturbances, such as their size. In block 404, it may be determined that a braking event is in progress. In block 406, the active suspension system may be controlled together with the braking system based on the forward monitoring road information and road disturbances. In block 408, the normal component of the wheel force at the wheel is adjusted by the active suspension system to increase wheel traction when the wheel encounters a road disturbance. For example, in some embodiments, a torsional force may be applied to the vehicle. As another example, in some embodiments, the pitch of the vehicle may be adjusted to temporarily increase the normal force load on the wheel. The method in Figure 9 employs forward-monitoring road information, but this disclosure is not so limited, and it should be noted that reference road information may also be employed alone or in combination with forward-monitoring road information. In some embodiments, the method may also include determining the expected response of the vehicle during a braking event. For example, in some embodiments, determining the expected response may include determining the expected loss of braking force based on road disturbances. The method may include controlling the braking system and the active suspension system (e.g., adjusting the normal force load on the wheels to compensate for road disturbances) at least in part based on the determined expected response.

[0078]

[0097] Figure 10 is a flowchart of yet another embodiment of a method for controlling a vehicle. In block 500, it is determined that a braking event is in progress. In block 502, the frequency range of the vehicle's pitch vibration is determined. In some embodiments, the range of pitch frequencies may be determined based on, for example, previously collected and stored data or information from an IMU. In some embodiments, the range of pitch frequencies may be determined based on information from a braking system. In block 504, the normal component of the wheel force at the wheel may be tuned by the active suspension system based at least in part on the range of pitch vibration frequencies. In block 506, the vehicle is damped at pitch frequencies within the range of frequencies in block 502. In some cases, different parts of the vehicle may be damped depending on the range of pitch frequencies. For example, in some embodiments, a pitch frequency range between 1 and 10 Hz may result in damping of the vehicle's sprung mass. As another example, in some embodiments, a pitch frequency between 10 and 25 Hz may result in damping of the vehicle's unsprung mass. In some embodiments, the method may also include determining the expected response of the vehicle during a braking event. For example, in some embodiments, determining the expected response may include determining the expected loss of braking force based on the pitch vibration frequency. The method may include controlling the braking system and the active suspension system (e.g., adjusting the normal force load on the wheel to dampen the pitch vibration) at least in part based on the determined expected response.

[0079]

[0098] Figures 11A-11D depict a scenario in which vehicle 100 is in a combined cornering and braking event. As shown in Figure 11A, vehicle 100 includes a first wheel 150a (e.g., left front wheel), a second wheel 150b (e.g., right front wheel), a third wheel 150c (e.g., left rear wheel), and a fourth wheel 150d (e.g., right rear wheel). The wheel sizes shown in Figures 11A-11D correspond to the normal components of the wheel forces at each wheel. As shown in Figure 11A, the vehicle is in a steady state, and the normal components are balanced accordingly and approximately equal to each other. The vehicle includes an active suspension system which may be configured to independently adjust the normal components of the wheel forces at each wheel. As shown in Figure 11A, the vehicle is in a first state before initiating a braking and cornering event at line 204.

[0080]

[0099] Figure 11B is a schematic diagram of vehicle 100 in Figure 11A in a second state after braking and cornering events have begun. As shown in Figure 11B, the application of braking force results in a load transfer from the rear wheels 150c and 150d to the front wheels 150a and 150b, and consequently the normal force increases. Compared to Figure 11A, the normal force load on the first wheel 150a and the second wheel 150b is larger, while the normal force load on the third wheel 150c and the fourth wheel 150d is smaller. In the state shown in Figure 11B, the active suspension is not operating, and the vehicle has not yet begun to turn.

[0081]

[0100] Figure 11C is a schematic diagram of vehicle 100 in Figure 11A in the third state, when turning has begun. As shown in Figure 11C, initiating a turn induces a roll acceleration in the vehicle, causing a load transfer from one side of the vehicle to the other. In particular, the normal load moves from the right side of the vehicle to the left side. As a result, the first wheel 150a has a larger normal load than in the state of Figure 11B, and the second wheel 150b has a smaller normal load than in the state of Figure 11B. Similarly, the third wheel 150c has a larger normal load than in its state in Figure 11B, while the fourth wheel 150d has a smaller normal load than in its state in Figure 11B. As a result, the difference in normal loads induces a yaw moment in the vehicle that prompts the vehicle to move away from the turning section. The vehicle control system can detect this difference and the difference in wheel slip, as shown in Figure 11D, and adjust the normal force load on the wheels with the active suspension system.

[0082]

[0101] Figure 11D is a schematic diagram of vehicle 100 in Figure 11A in the fourth state. As shown in Figure 11D, a torsional force is applied to the vehicle. In particular, the normal load increases on the second wheel 150b and the third wheel 150c. As a result, the normal force load is shifted away from the first wheel 150a and the fourth wheel 150d. According to the embodiment of Figure 11D, the normal loads on the first wheel 150a and the second wheel 150b become approximately equal. Therefore, the yaw moment caused by the braking difference between the two front wheels can be reduced or eliminated. Furthermore, the application of torsional force may allow the normal force load to be more evenly distributed among the first, second, and third wheels, enabling the vehicle to stay on the intended path during cornering. In addition, since more normal load may be applied to the front wheels 150a and 150b as a whole, the overall braking force may increase compared to a passive suspension system. Thus, the adjustment of normal forces by an active suspension system can improve the vehicle's performance in cornering and / or braking events. In some embodiments, a vehicle control system may determine that a braking force request exceeds a threshold braking force and, in response, apply a torsional force to the vehicle to ensure that the desired braking force is generated for a particular scenario.

[0083]

[0102] In some embodiments, the application of torsional forces in this scenario may depend on the observation of a desired yaw motion of the vehicle. For example, if the vehicle is determined to be understeering too much (e.g., if the vehicle's yaw rate is determined to be at least equal to a threshold value lower than a desired yaw rate determined by the control system), the active suspension force may be applied as described in Figures 11A-D. For example, if the vehicle is determined to be oversteering too much (e.g., if the vehicle's yaw rate is determined to be at least equal to a threshold value higher than a desired yaw rate determined by the control system), the application of the active suspension force may be reversed to increase the normal loads on the first wheel 150a and the fourth wheel 150d and decrease the normal loads on the second wheel 150b and the third wheel 150c. In some embodiments, the application of this force may be dynamically changed to control the vehicle's yaw response to match a desired response. In some embodiments, this desired response may be determined by calculation in the vehicle control system or may be determined in advance.

[0084]

[0103] Figure 12 is a flowchart of yet another embodiment of a method for controlling a vehicle. In block 600, it is determined that a braking event is in progress. In block 602, the steering angle of the vehicle is determined (e.g., using information from a rotary encoder, potentiometer, or other suitable sensor). In block 604, it is determined that the braking force request to the wheel during the braking event exceeds a threshold braking force. In some embodiments, such determination may be based on the operation of the ABS system. In some embodiments, such determination may be based on the amount of braking force applied by the user of the vehicle (e.g., brake pedal force), or on the timing or speed of such application. In block 606, the normal component of the first wheel force at the wheel is adjusted by the active suspension system to increase wheel traction. In block 608, the normal component of the second wheel force at the second wheel is adjusted by the active suspension system. In some embodiments, the first and second wheels may be positioned at opposite corners of the vehicle so that torsional forces are applied to the vehicle. In some embodiments, the method may also include determining the expected response of the vehicle during a braking event. For example, in some embodiments, determining the expected response may include determining that understeer will occur based on the load transfer described with reference to Figures 11A-11D. The method may include controlling the braking system and the active suspension system (e.g., applying torsional forces) at least in part based on the determined expected response.

[0085]

[0104] The embodiments of the technology described herein can be implemented in any of a number of ways. For example, embodiments can be implemented using hardware, software, or a combination thereof. When implemented in software, the software code can run on any suitable processor or array of processors, whether located on a single computer or distributed across multiple computers. Such a processor may be implemented as an integrated circuit having one or more processors within an integrated circuit component, including commercially available integrated circuit components known in the art as CPU chips, GPU chips, microprocessors, microcontrollers, or coprocessors. Alternatively, the processor may be implemented in a custom circuit such as an ASIC, or a semi-custom circuit resulting from constituting a programmable logic device. As yet another alternative, the processor may be part of a larger circuit or semiconductor device, whether commercial, semi-custom, or custom. As a specific example, some commercial microprocessors have multiple cores, and one or a subset of those cores may constitute a processor. However, the processor can be implemented using any suitable form of circuit.

[0086]

[0105] Furthermore, it should be understood that a computer may be embodied in any of many forms, such as a rack-mount computer, a desktop computer, a laptop computer, or a tablet computer. Additionally, a computer may be incorporated into devices that are not generally considered computers but possess sufficient processing power, including personal digital assistants (PDAs), smartphones, or any other suitable portable or fixed electronic devices.

[0087]

[0106] Furthermore, a computer may have one or more input and output devices. These devices can, among other things, be used to present a user interface. Examples of output devices that can be used to provide a user interface include a printer or display screen for visually presenting output, and a speaker or other sound-generating device for audibly presenting output. Examples of input devices that can be used for a user interface include a keyboard and pointing devices such as a mouse, touchpad, and digital tablet. As another example, a computer may receive input information through speech recognition or in other audible formats.

[0088]

[0107] Such computers may be interconnected by one or more networks of any suitable form, including local area networks or wide area networks, such as corporate networks or the Internet. Such networks may be based on any suitable technology, may operate according to any suitable protocol, and may include wireless networks, wired networks, or fiber optic networks.

[0089]

[0108] Furthermore, the various methods or processes outlined herein may be coded as software executable on one or more processors employing any one of various operating systems or platforms. Moreover, such software may be written using any of a number of suitable programming languages ​​and / or programming or scripting tools, and may be compiled as executable machine code or intermediate code that runs on a framework or virtual machine.

[0090]

[0109] In this regard, embodiments described herein may be embodied as computer-readable storage media (or more computer-readable media) (e.g., computer memory, one or more floppy disks, compact discs (CDs), optical discs, digital video discs (DVDs), magnetic tape, flash memory, field-programmable gate arrays or other semiconductor device circuit configurations, or other tangible computer storage media) coded in one or more programs that, when executed on one or more computers or other processors, perform methods for carrying out the various embodiments described above. As is evident from the examples above, computer-readable storage media may retain information for a sufficient amount of time to provide computer-executable instructions in a non-temporary form. One or more such computer-readable storage media may be transportable so that one or more programs stored thereon can be loaded onto one or more different computers or other processors to carry out the various embodiments of the disclosure described above. As used herein, the term “computer-readable storage media” includes only non-temporary computer-readable media that can be considered as products (i.e., manufactured goods) or machines. Alternatively or additionally, the Disclosure may be embodied in a computer-readable medium other than a computer-readable storage medium, such as a propagating signal.

[0091]

[0110] The terms “program” or “software” are used herein in a general sense to refer to any type of computer code or set of computer executable instructions that can be employed to program a computer or other processor to implement various aspects of the Disclosure as described above. Furthermore, it should be understood that, according to one aspect of this embodiment, one or more computer programs that, when executed, perform the methods of the Disclosure do not need to reside on a single computer or processor, but can be modularly distributed among many different computers or processors to implement various aspects of the Disclosure.

[0092]

[0111] Computer executable instructions can take many forms, such as program modules, which are executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. Generally, the functions of program modules can be combined or distributed as desired in various embodiments.

[0093]

[0112] Furthermore, the data structure may be stored in a computer-readable medium in any suitable form. For simplicity of explanation, the data structure may be shown as having related fields via locations within the data structure. Such relationships may also be achieved by allocating storage for fields that have locations in a computer-readable medium that convey the relationships between fields. However, any suitable mechanism may be used to establish relationships between the information of the fields in the data structure, such as the use of pointers, tags, or other mechanisms for establishing relationships between data elements.

[0094]

[0113] Various aspects of this disclosure can be used individually, in combination, or in various arrangements not specifically considered in the embodiments described above, and their application is not limited to the details and arrangements of components specified in the prior description or illustrated in the drawings. For example, an aspect described in one embodiment can be combined in any manner with an aspect described in another embodiment.

[0095]

[0114] Furthermore, embodiments described herein may be embodied as an example provided. The actions performed as part of the method may be ordered in any suitable manner. Thus, embodiments may be constructed in which the actions are performed in a different order than the examples, including performing several actions simultaneously, even if they are shown as a series of actions in the exemplary embodiments.

[0096]

[0115] Furthermore, some actions are described as being performed by a “user.” It should be understood that the “user” does not necessarily have to be a single individual, and in some embodiments, actions attributed to a “user” may be performed by a team of individuals and / or individuals in combination with computer-aided tools or other mechanisms.

[0097]

[0116] Although these instructions have been described in conjunction with various embodiments and examples, they are not intended to be limited to such embodiments or examples. Rather, these instructions encompass a variety of substitutes, modifications, and equivalents, as will be understood by those skilled in the art. Therefore, the foregoing descriptions and drawings are merely illustrative.

Claims

1. The first wheel and, The second wheel, A braking system configured to apply braking force to the first wheel and the second wheel, An active suspension system operably coupled to the first wheel and the second wheel, configured to apply an active force to the first wheel and the second wheel in at least one operating mode to adjust the normal component of the first wheel contact force between the first wheel and the road surface, and to adjust the normal component of the second wheel contact force between the second wheel and the road surface, A forward monitoring sensor configured to detect forward monitoring road information, At least one processor configured to control the braking system and the active suspension system, The forward monitoring road information is received from the forward monitoring sensor. Based at least partially on the sensed forward-monitoring road information, the braking system and the active suspension system are coordinately controlled to adjust the vehicle's pitch. At least one processor configured as follows and A vehicle equipped with the following features.

2. The vehicle according to claim 1, wherein the first wheel is the front wheel of the vehicle, the second wheel is the rear wheel of the vehicle, and the first wheel and the second wheel are positioned at opposite corners of the vehicle.

3. The vehicle according to claim 2, wherein the at least one processor is configured to control the active suspension system to increase the normal component of the first wheel and the normal component of the second wheel based on the forward-monitoring road information.

4. The vehicle according to claim 3, wherein the forward-monitoring road information includes road disturbances.

5. The vehicle according to claim 4, wherein the road disturbance is a change in road surface friction relative to nominal road friction.

6. The vehicle according to claim 3, wherein the forward-monitoring road information includes a turning section.

7. The vehicle according to claim 1, wherein the first wheel is the first front wheel of the vehicle, and the second wheel is the second front wheel of the vehicle.

8. The vehicle according to claim 7, wherein the forward-monitoring road information includes road disturbances, and the at least one processor is configured to control the active suspension system to temporarily increase the normal component of the first wheel contact force and the normal component of the second wheel contact force based on the road disturbances.

9. The vehicle according to claim 7, wherein the at least one processor is configured to determine that a braking event is in progress, the at least one processor is configured to determine the pitch frequency of the vehicle based on the braking event, and the at least one processor is configured to control the active suspension system to adjust the pitch of the vehicle based on the determined pitch frequency.

10. The vehicle according to claim 1, wherein the first wheel is a first side wheel of the vehicle, the second wheel is a second side wheel of the vehicle positioned on the same side of the vehicle, and the at least one processor is configured to control the active suspension system to adjust the roll of the vehicle.

11. The vehicle according to claim 10, wherein the forward-monitoring road information includes road disturbances, and the at least one processor is configured to control the active suspension system to temporarily increase the normal component of the first wheel contact force and the normal component of the second wheel contact force based on the road disturbances.

12. The aforementioned at least one processor, It was determined that a braking event was in progress. Determine the expected response of the vehicle during the braking event, Based on the expected response, the braking system and the active suspension system are controlled. A vehicle according to any one of claims 1 to 8 or 10 or 11, configured as described above.

13. The vehicle according to claim 1, wherein the forward-monitoring road information includes road disturbances with disturbance size, the at least one processor is configured to determine whether the disturbance size exceeds an activation threshold, and the at least one processor is configured to disable the active suspension system if the disturbance size does not exceed an activation threshold during the duration of a braking event.

14. The vehicle according to any one of claims 1 to 11, wherein the forward-facing sensor is a LIDAR.

15. The vehicle according to any one of claims 1 to 11, wherein the forward-facing monitoring sensor is at least one camera.

16. A method for controlling a vehicle including a braking system and an active suspension system, To determine that a braking event is in progress, To determine the pitch frequency of the pitch vibration of the aforementioned vehicle, The active suspension system adjusts the normal component of the wheel force in one or more wheels, and dampens the pitch vibration at the pitch frequency during the braking event. A method that includes this.

17. The method according to claim 16, further comprising sensing forward monitoring road information with a forward monitoring sensor, wherein determining the pitch frequency is at least partially based on the forward monitoring road information.

18. The method according to claim 16 or 17, further comprising obtaining reference road information, wherein determining the pitch frequency is at least partially based on the reference road information.

19. The method according to claim 18, wherein acquiring the reference road information includes receiving the reference road information from a second vehicle located in front of the vehicle.

20. To determine the braking force requirement, Determining whether the braking force request exceeds the threshold braking force, If it is determined that the braking force request does not exceed the threshold braking force, the active suspension system is disabled for the duration of the braking event. The method according to any one of claims 16 to 17, further comprising:

Images