Method and apparatus for on-center steering and fast response vehicle

Abstract

To modify the natural response of the controlled vehicle to produce a more desired forced response, by using an active suspension actuator.SOLUTION: A system and a method for controlling responses (roll and pitch) of a vehicle body with respect to inputs from a driver are disclosed. In an embodiment, the method for controlling the responses of the vehicle body is disclosed. The method comprises receiving inputs (steering input and pedal input) from an operator of the vehicle, and modifying aspects of responses of the vehicle (roll angle, pitch angle, roll change rate, pitch change rate), and the modified aspects have values based at least partially on the inputs. In other aspects, there is disclosed a controlled vehicle including a vehicle body, and one or more actuators configured to apply torque to the vehicle body, the torque having a direction and / or magnitude based at least partially on driver's inputs (steering command, brake command, acceleration command).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE

[0001] The disclosed embodiments relate generally to vehicle responsiveness, and more particularly to vehicle steering, including on-center steering. [Background technology]

[0002]

[0002] A significant portion of a vehicle's interaction with its occupants, and particularly the driver, is determined by control inputs provided by the steering wheel, accelerator pedal, and / or brake pedal. Responses to such inputs from these devices can vary significantly from vehicle to vehicle. Summary of the Invention

[0003] In some embodiments, the response to a particular driver input or command, provided, for example, using a steering wheel and / or one or more pedals, such as a brake pedal and / or a gas pedal, is caused, influenced, or adjusted by the application of one or more active forces. These active forces may be applied to the vehicle's body, for example, by one or more actuators of an active suspension system. In some embodiments, the intervention of the active suspension system may cause the vehicle to appear more responsive to the vehicle's driver than it would be in the absence of the application of the active forces. In some embodiments, for example, a vehicle controller may determine the expected intrinsic response of a controlled vehicle to one or more driver inputs in a particular driving condition. The controller may then use active suspension actuators to modify the intrinsic response of the controlled vehicle to produce a more desirable forced response. This forced response may, for example, approximate or replicate the intrinsic response of a real or virtual target vehicle in one or more respects.

[0004] For example, in one embodiment, a vehicle controller may receive driver-generated inputs and / or information regarding vehicle operating parameters, including, for example, steering wheel position (δ) from a steering wheel sensor, accelerator pedal position from an accelerator pedal position (α) sensor, brake pedal position from a brake pedal position sensor (β), drive or brake torques applied to the wheels, command or measurement signals for a steer-by-wire or rear-steer system, first, second or higher order time derivatives of such quantities, and / or vehicle speed from a sensor capable of measuring vehicle speed. Based on one or more such parameters and such driver input information, and information regarding the difference between the expected intrinsic response of the controlled vehicle to these inputs and the desired target response, the controller may react to these inputs by applying one or more active forces using one or more actuators of the vehicle. The applied active forces may, for example, generate, modify or augment a particular response indicia, such as, for example, roll, heave and / or pitch parameters of the vehicle.

[0005] In some embodiments, under certain driving conditions, the response indication received by the driver may be, for example, a roll angle (φ),

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[0006]

[0006] As used herein, the term "responsiveness" is interpreted to mean how quickly the vehicle's response to driver-generated input is perceived by the driver.

[0007]

[0007] As used in this specification, the term "active force" means a force applied to the vehicle body in the direction of the vehicle body's motion at the time the force is applied, whereas the term "passive force" (or "damping force") is interpreted to mean a force applied to the vehicle body in a direction opposite to the direction of the vehicle body's motion at the time the force is applied.

[0008]

[0008] As used in this specification, the "intrinsic response" of a vehicle to a particular command or input by a vehicle operator is interpreted to mean the response of the vehicle in the absence or substantial absence of the application of active forces to the vehicle body to induce, reinforce and / or correct roll and / or pitch of the vehicle.

[0009]

[0009] As used in this specification, the term "forced response" of a vehicle to a particular command or input by a vehicle operator is interpreted to mean, for example, the roll and / or pitch of the vehicle, which is reinforced or corrected, for example, by the application of one or more active forces.

[0010]

[0010] As used herein, the term "controlled vehicle," unless the context indicates otherwise, means a vehicle capable of applying active forces using the vehicle's active suspension system to induce or modify body roll and / or pitch moments in response to vehicle inputs. The active forces may be applied in response to steering wheel and / or pedal inputs provided by the driver. The resulting roll and / or pitch moments may, under certain conditions, move the vehicle in a manner that is perceived as more responsive to the driver input than the intrinsic response.

[0011]

[0011] As used herein, the term "target response" of a vehicle to a particular command or input by a vehicle operator is interpreted to mean a desired response that may be faster than the intrinsic response of a controlled vehicle. The target response may be defined based on, for example, previously acquired feedback from one or more vehicle occupants of the controlled vehicle itself, previously acquired response data from other vehicles (e.g., models similar or identical to the controlled vehicle), response data from a numerical model predicted performance of other vehicle models that may be considered to have a desired response (e.g., a 2016 Ferrari 488 GTB, or other vehicles with similar responses), responses of actual target vehicles with preselected response characteristics, and / or responses of virtual target vehicles.

[0012]

[0012] As used herein, the term "inside" (or inside) with respect to the body making the turn is interpreted to mean (a) the driver's side (in a vehicle configured for domestic driving) when the vehicle is turning left (from the driver's perspective) and (b) the passenger's side (in a vehicle configured for domestic driving) when the vehicle is turning right (from the driver's perspective). Similarly, the term "outside" (or outside) with respect to the body making the turn is interpreted to mean (a) the driver's side (in a vehicle configured for domestic driving) when the vehicle is turning right (from the driver's perspective) and (b) the passenger's side (in a vehicle configured for domestic driving) when the vehicle is turning left (from the driver's perspective). As used herein, roll is said to be "positive" or "away" from the direction of the turn when the body rolls such that the outside of the body is lowered vertically relative to the inside of the body (or, in other words, the inside of the body is raised vertically relative to the outside of the body). Roll motion is said to be "negative", or "into" a turn, when the outside of the vehicle is raised vertically relative to the inside of the vehicle.

[0013] In one aspect, a method of controlling a body response of a controlled vehicle is disclosed, the method including: (a) receiving an input from a driver or a signal from a control system in the case of an autonomous or semi-autonomous vehicle; and (b) modifying an aspect of the body response, the response being at least one of roll and pitch, the aspect being at least one of velocity and magnitude, and a value of the aspect being based at least in part on the input. In one embodiment, modifying the aspect of the vehicle response includes applying a first force to the body by one or more actuators of an active suspension system of the controlled vehicle. In one embodiment, the input is a change in steering angle commanding the vehicle to turn in a turn direction, and the first force is a torque away from the turn direction. In one embodiment, the input is a change in steering wheel angle to command the controlled vehicle to turn in a turning direction, and the first force includes at least one of (i) an upward force applied to a first body corner located along the inside of the controlled vehicle, and (ii) a downward force applied to a second body corner located along the outside of the controlled vehicle. In one embodiment, the input is a change in brake pedal position to command the controlled vehicle to brake, and the first force is a torque that causes a front end of the body to lower vertically relative to a rear end of the body. In one embodiment, the input is a change in brake pedal position to command the controlled vehicle to brake, and the first force includes at least one of (i) an upward force applied to a first body corner located at the front end of the controlled vehicle, and (ii) a downward force applied to a second body corner located at the rear end of the controlled vehicle. In one embodiment, the input is a change in accelerator pedal (e.g., gas pedal) position commanding the controlled vehicle to accelerate (or decelerate), and the first force is a torque causing the rear end of the controlled vehicle to lift vertically relative to the front end of the controlled vehicle.In some embodiments, the input is a change in accelerator pedal (e.g., gas pedal) position commanding the controlled vehicle to accelerate, and the first force includes at least one (e.g., at least one, both) of (i) a downward force applied to a first corner of the body located at a front end of the controlled vehicle, and (ii) an upward force applied to a second corner of the body located at a rear end of the controlled vehicle. In some embodiments, the body has a unique response to the input, and the first force has a direction equal to the direction of the unique response. In some embodiments, the aspect is rate of change and the response is roll. In some embodiments, the aspect is rate of change and the response is pitch.

[0014]

[0014] In another aspect, a method is disclosed for controlling a forced response of a body of a controlled vehicle to a command (e.g., a braking command, an acceleration command, a steering command), the method including: (a) receiving, measuring, estimating, or deriving a command to perform a first maneuver by the vehicle (e.g., to accelerate the vehicle in a forward direction, to decelerate the vehicle in a forward direction, to turn the vehicle in a first direction (e.g., left, right)); (b) determining a direction of an intrinsic response to the command, the intrinsic response including at least one of a roll, a heave, and a pitch movement; and (c) applying a first force (e.g., a linear force, a torque) to the body in the direction of the intrinsic response by one or more (e.g., at least one, at least two, at least three, at least four) active suspension actuators, thereby producing a forced response (e.g., the forced response including at least one of an active roll, an active heave, and an active pitch movement). In one embodiment, the first force is applied before the intrinsic response begins and before the command is received. In some embodiments, step (b) further includes determining a specific rate of change (e.g., speed) of the specific reaction, the forced reaction having a rate of change faster than the specific rate of change. In some embodiments, step (b) further includes determining a specific magnitude of the specific reaction, the forced reaction having a magnitude that is at least one of equal to the specific magnitude and greater than the specific magnitude. In some embodiments, the first maneuver has a time period that lasts from a first time point to a second time point, and the method further includes ceasing application of the first force at a third time point, the third time point being later than the first time point and earlier than the second time point. In some embodiments, the first maneuver includes turning in a turning direction (e.g., left, right) and the specific reaction includes rolling away from the turning direction (i.e., the outside of the body is lowered relative to the inside of the body). In some embodiments, the maneuver includes braking (e.g., decelerating in a forward direction) and the specific reaction is pitching in a forward direction (i.e., the front end of the body is lowered relative to the rear end of the body).

[0015]

[0015] In another embodiment, a method for controlling a forced response (e.g., active roll, active pitch, active heave) of a body of a controlled vehicle (e.g., a vehicle including an active suspension system) to a specific command (e.g., a braking command, an acceleration command, a steering command), the method includes: (a) receiving a specific command for a first steering by the controlled vehicle, the specific command including at least one of a steering command, a braking command, and an acceleration command; and (b) determining a target direction (e.g., roll direction, pitch direction, heave direction), a target magnitude (e.g., roll magnitude, pitch magnitude, heave magnitude) and a target velocity (e.g., velocity, velocity, velocity) based on the specific command. (c) determining a specific target body response (e.g., target roll, target pitch, target heave) having a specific set of target aspects including at least one of a target roll rate, a target pitch rate, a target heave rate, a target roll rate, a target pitch rate, a target heave rate; (d) applying the first force (e.g., linear force, torque) to the body by one or more (e.g., at least one, at least two, at least three, at least four) active suspension actuators, thereby causing a forced reaction of the body. In one embodiment, the forced reaction includes a movement having an active direction equal to a direction of the specific target body reaction. In one embodiment, the forced reaction includes a movement having an active rate equal to a rate of change of the specific target body reaction. In one embodiment, the forced reaction includes a movement having an active magnitude equal to a magnitude of the specific target body reaction.

[0016]

[0016] In one embodiment, the step (b) further includes obtaining a model (e.g., a set of rules, a set of functions) of the target vehicle, the model defining a target response of the target body as a function of at least one of a reference steering command, a reference acceleration command, and a reference braking command, and further includes calculating a specific target body response by evaluating the specific command against the model. In one embodiment, the target vehicle has a passive or semi-active suspension system. In one embodiment, the target vehicle has a first yaw inertia, and the controlled vehicle has a second yaw inertia greater than the first yaw inertia. In one embodiment, step (c) further includes determining a specific response to the command, the specific response having a second set of aspects including at least one of a specific direction (e.g., roll direction, pitch direction, heave direction), a specific magnitude (e.g., roll magnitude, pitch magnitude, heave magnitude), and a specific target rate of change (e.g., roll rate, pitch rate, heave rate), calculating a difference between the second set of aspects and the first set of aspects, and determining a first force based on the difference. In one embodiment, the first force is applied in a specific direction.

[0017]

[0017] In another aspect, a method is disclosed for controlling a forced response of a body of a vehicle (e.g., a vehicle including an active suspension system) to a steering command, the method including rotating a steering wheel of the vehicle to a first position at a first rate of change of rotation, determining a first force (e.g., linear force, torque) based on at least one (e.g., at least one, at least two) of the first position and the first rate of change, and applying the first force to the body by one or more (e.g., at least one, at least two, at least three, at least four) active suspension actuators, thereby producing a forced response (e.g., the forced response includes at least one of an active roll, an active heave, and an active pitch movement). In one embodiment, rotating the steering wheel causes the vehicle to turn left (e.g., toward the driver's side in a vehicle configured for the United States), and the first force is a torque having a clockwise direction (i.e., clockwise as perceived by an observer behind the vehicle). In another embodiment, the vehicle is turned right (to the passenger side in a vehicle configured for the United States) by turning the steering wheel, and the first force is a torque having a counterclockwise direction (i.e., counterclockwise as perceived by an observer behind the vehicle).

[0018] In yet another aspect, a method is disclosed for controlling a forced response of a body of a vehicle (e.g., a vehicle including an active suspension system) to an acceleration command, the method including: changing a position of a pedal of the vehicle, one of an accelerator pedal (e.g., a gas pedal) and a brake pedal, from a first position to a second position at a first rate of change; determining a first force (e.g., linear force, torque) based on at least one (e.g., at least one, at least two) of the first position, the second position, and the first rate of change; and applying a first force to the body by one or more (e.g., at least one, at least two, at least three, at least four) active suspension actuators, thereby producing a forced response (e.g., the forced response includes at least one of an active roll, an active heave, and an active pitch movement). In one embodiment, changing the position of the pedal accelerates the vehicle in a forward direction, and the first force causes a rear end of the vehicle to lower vertically relative to a front end of the vehicle. In other embodiments, changing the position of the pedal causes the vehicle to decelerate in a forward direction and the first force causes the front end of the vehicle to lower vertically relative to the rear end of the vehicle.

[0019]

[0019] In yet another aspect, a vehicle is disclosed that includes a vehicle body and a first set of one or more (e.g., one, two, three, four) active suspension actuators configured to apply a torque to the vehicle body in a clockwise direction (i.e., clockwise as perceived by an observer behind the vehicle) in response to a steering command commanding the vehicle to turn left (i.e., toward the driver's side in a vehicle configured for the United States).

[0020]

[0020] In yet another aspect, a vehicle is disclosed that includes a vehicle body and a first set of one or more (e.g., one, two, three, four) active suspension actuators configured to apply a torque to the vehicle body in a counterclockwise direction (i.e., counterclockwise as perceived by an observer behind the vehicle) in response to a steering command commanding the vehicle to turn right (i.e., to the passenger side in a vehicle configured for the United States).

[0021]

[0021] The foregoing summary, including the above and other features and advantages of vehicle active suspension or other control systems and methods, and the brief description of the preferred embodiments of the present invention, will be better understood when read in conjunction with the accompanying drawings. Drawings and schematic diagrams are provided to illustrate one or more embodiments of the present invention and to explain its operation. However, the present invention is not limited to the exact configurations, variations, structures, features, embodiments, aspects, methods, advantages, improvements, and means shown, and the configurations, variations, structures, features, embodiments, aspects, methods, advantages, improvements, and means shown and / or described may be used alone in the system or method, or may be used in combination with other configurations, variations, structures, features, embodiments, aspects, and means. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a schematic diagram showing the top and side of a vehicle responding to steering wheel angle input. [Diagram 2]

[0023] FIG. 2 illustrates a driver input of steering wheel angle in an exemplary controlled vehicle and roll angle responses of the controlled and target vehicles. [Diagram 3]

[0024] FIG. 1 shows a schematic of the front of a vehicle responding to a steering angle input. [Figure 4]

[0025] FIG. 1 is a schematic diagram showing an embodiment of a two-wheeled vehicle model. [Diagram 5]

[0026] FIG. 2 is a schematic block diagram illustrating an embodiment of a controller algorithm for controlling vehicle response to driver input. [Figure 6]

[0027] 4 is a graph showing model outputs for a controlled vehicle and a more responsive target vehicle responding to a step change in steering input. [Figure 7]

[0028] FIG. 13 is a schematic block diagram showing a roll force command algorithm. [Figure 8]

[0029] FIG. 1 illustrates an example of one embodiment of an algorithm used to calculate a desired movement pattern in response to a given input. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023]

[0030] Certain exemplary embodiments are described below to provide a comprehensive understanding of the principles of the structure, function, manufacture, and use of the systems and methods disclosed herein for vehicle response control systems. One or more examples of these embodiments are illustrated in the accompanying drawings and described herein. Those skilled in the art will appreciate that the systems, methods, and examples described herein and shown in the accompanying drawings are non-limiting exemplary embodiments, and that the scope of the invention is defined solely by the claims. Features illustrated or described in connection with one embodiment may be combined with features of other embodiments, and these features may be used individually, alone, and / or in various combinations. Such variations are intended to be within the scope of the present disclosure.

[0024]

[0031] An important and desired aspect of modern vehicles is their ability to respond immediately and predictably to input commands from the driver, such as steering, accelerator, and / or brake pedal inputs. These inputs may include acceleration of the vehicle body in one or more directions, subjecting the vehicle and occupants to certain inertial forces.

[0025]

[0032] Through experimentation and analysis, the inventors have recognized that a driver's perception of a vehicle's responsiveness may depend, at least in part, on one or more responsive indicators that are detected or felt by the driver, but that may be attributable to driver-generated inputs. For example, when a driver generates a steering input by turning the vehicle's steering wheel, the driver may sense a lateral acceleration of the vehicle. In a responsive vehicle, this sensed indicator may appear quickly and be highly damped, i.e., it does not persist long after the input ceases to change. For example, in some embodiments, a highly responsive vehicle may have a roll direction natural frequency of up to 5 Hz with a near-critical damping coefficient of at least 0.7, while a less responsive vehicle may have a frequency of about 1.5 Hz and a damping coefficient of about 0.4 or less. It is understood that the present disclosure is not limited thereto, and that natural frequencies and damping coefficients outside the ranges set forth above for each vehicle type may be exhibited by responsive and less responsive vehicles. The inventors have recognized that a driver may perceive a vehicle's response to a driver input in several different ways. For example, in some embodiments, the inherent response of the vehicle may result in a sensation of lateral or longitudinal acceleration and / or a sensation of change in the roll and / or pitch angles of the vehicle, and the rate at which these quantities change and / or the derivative of the rate of change may be sensed by the driver and interpreted as a responsiveness indicator to steering and / or pedal commands. The driver may perceive the length of time between when an input command is given and when a particular responsiveness indicator is sensed as a measure of the responsiveness of the vehicle.

[0026]

[0033] The perceived responsiveness of a vehicle can vary over a wide range; for example, a 2016 Ferrari 488 GTB or a vehicle with comparable responsiveness may be considered extremely responsive, a 2016 BMW 5 Series or a vehicle with comparable responsiveness may be considered moderately responsive, and a 2016 Lincoln Navigator or a vehicle with comparable responsiveness may be considered poorly responsive.

[0027]

[0034] The inventors have also recognized that in certain embodiments, regardless of the actual intrinsic response of the vehicle, the perceived response of the vehicle to driver-generated commands may be improved by using one or more actuators to at least temporarily induce, modify or augment roll, heave and / or pitch moments applied to the vehicle.

[0028]

[0035] The inventors further recognized that many drivers also find it reassuring and / or desirable when the vehicle's response is perceived to be linear or proportional to the driver's command input. For example, in the case of a steering command, drivers prefer a steering system having a "V" shaped steering response, where the vehicle's response is directly proportional to the steering angle input, rather than a "U" shaped response, where the response is a non-linear function of the steering input, where the response is defined to include, for example, one or more of the perceived response indicia described above and other indicia, such as steering torque, steering torque rate of change, and audible response from the power steering system.

[0029]

[0036] Through experimentation, the inventors have realized that the active suspension system of the vehicle can be used to quickly provide a specific responsive indication that will be perceived by the driver. By providing one or more such indications, the vehicle can be made to appear much more responsive. In some embodiments, the responsive indication can be directly proportional to the driver input. For example, in some embodiments, if the responsive indication is the vehicle roll angle and the driver input is the steering wheel angle, the roll angle can be directly proportional to the negative of the steering wheel angle.

[0030]

[0037] In some embodiments, active suspension systems can be used to improve the on-center steering feel and / or behavior of a vehicle. For example, as a driver changes the steering wheel angle to properly center the vehicle in its lane, active suspension actuators can be used to provide a cue to the driver commensurate with the steering input.

[0031]

[0038] The timing, magnitude and duration of application of active forces to the vehicle body through the employment of an active suspension system may depend on the inherent response of the vehicle and the defined target vehicle response.

[0032]

[0039] Through experimentation and analysis, the inventors have recognized that a driver's perception of vehicle responsiveness may depend, at least in part, on one or more responsive signatures detected or felt by the driver that result from driver-generated inputs. For example, when a driver generates a steering input by turning the steering wheel, the driver may sense a lateral acceleration of the vehicle. In a responsive vehicle, this sensed acceleration signature appears quickly and is highly damped, i.e., does not persist long after the input ceases to change. For example, in some embodiments, a highly responsive vehicle may have a roll direction natural frequency of up to 5 Hz with a near-critical damping coefficient of at least 0.7, while a less responsive vehicle may have a frequency of about 1.5 Hz and a damping coefficient of about 0.4 or less. It is understood that the present disclosure is not so limited, and that natural frequencies and damping coefficients outside the ranges set forth above for each vehicle type may be exhibited by responsive and less responsive vehicles.

[0033]

[0040] In some vehicles, the suspension system may be tuned so that the outer front corner dips when the vehicle is turning. For example, the suspension of a passive or semi-active vehicle may be tuned so that the vehicle is made to simultaneously roll and pitch while turning. This gives the driver the impression that the outer front end of the vehicle is "slumping" while turning, while at the same time the front end may be experiencing positive roll. In some vehicles, this squeezing motion can act as a responsive indicator.

[0034]

[0041] A vehicle may have a more rapid roll moment transfer on the rear axle through a high instantaneous roll center and a less rapid transfer on the front axle through a lower instantaneous roll center. Additionally or alternatively, a passive or semi-active front damper with an asymmetric damping ratio may be used. This allows the damper to be "softer" in one direction (typically the direction of shortening or compressing the damper) and "harder" in the opposite direction, thus allowing a corner of the car moving downward to move more aggressively than a corner of the car moving upward. This means that the initial reaction of the vehicle to a steering input is a roll acceleration, typically about an axis tilted downward and to the inside of the turn (the instantaneous roll axis of the vehicle). In other words, the outer front corner of the vehicle will squat at the beginning of the turn. A desired amount of selective squat of the front of the vehicle toward the outside of the turn can be achieved by "tuning" the damper and suspension system of the vehicle using a passive suspension.

[0035]

[0042] However, in certain vehicles, there may be a significant inherent delay in the vehicle's dynamic response to driver input. In such circumstances, the driver may not receive sufficient response indications quickly enough to assess the appropriateness or appropriateness of the input provided by the driver. If the driver cannot receive, for example, visual, tactile, and / or somatosensory response indications quickly enough, the driver may not have a sufficient feedback mechanism and effective control of the vehicle may become difficult.

[0036]

[0043] If the vehicle's response to driver inputs is inherently slow and largely nonlinear, the driver may be forced to constantly overcompensate, for example by constantly changing the steering angle, over-reacting and then trying too hard to correct the inputs. For example, a vehicle's response with excessively abrupt movements in the drivetrain may appear "sluggish" and non-linear. Even a normally quick-responding vehicle may appear sluggish if it has partially deflated tires (leading to a perception of "wobble") or deteriorated shock absorbers (leading to, for example, an uneven roll response).

[0037]

[0044] Even if the vehicle's responses are predictable, if they are not perceived as such by the driver, or are perceived as too slow, the driver may feel disconnected from the vehicle and unable to predict when a particular input will be sufficient and / or appropriate. Lack of sufficient feedback can lead to endless corrections and readjustments. During longer drives, this can lead to operator fatigue and an increased likelihood of accidents.

[0038] v Through experimentation, the inventors have recognized that the driver's perception of how the vehicle is responding in a particular situation is more important than the vehicle's actual response.

[0039]

[0045] Through experimentation, the inventors have recognized that in vehicles with active suspension systems, actuators can be used to provide the driver with certain responsive indications that can serve as effective feedback to driver inputs. These indications can substitute for or augment other slower feedback. Such proxy indications can include, for example, vehicle roll, vehicle pitch, and / or various combinations of first, second and / or higher derivatives of roll and / or pitch.

[0040]

[0046] In some vehicles, the inherent squat motion described above may occur with a significant delay and may not function as an effective responsive indicator. In vehicles with active suspension, actuators may be used to force a more immediate and / or exaggerated squat response. This modified squat response to driver input may make the driver believe the vehicle is more responsive.

[0041]

[0047] FIG. 1 shows a side view 1 and a top view 2 of a vehicle with an active suspension system. In one embodiment, the active suspension vehicle may appear to produce a desired squat movement of the left front corner 4 of the vehicle in response to a steering input commanding the vehicle to turn right 9 (which causes at least the front wheels 7 to turn), for example, although the orientation of the vehicle's roll axis 3 may be governed by the elastic kinematics of the suspension. One or more actuators of the active suspension system may be used to induce this movement in response to the driver's steering input. For example, a first actuator located at or near the left front corner 4 of the vehicle may be used to apply a vertical downward force to the vehicle body while a second actuator located at or near the right rear corner 6 of the vehicle may be used to simultaneously apply a vertical upward force to the vehicle body. The timing and magnitude of the squat may be determined based on, for example, previously collected data from the controlled vehicle, other similar vehicles, target vehicles, and / or simulation models defining the desired response.

[0042]

[0048] Through experimentation, the inventors have also recognized that in certain circumstances, one or more actuators of an active suspension system can be used to induce a forced roll and / or pitch response that can be independent of the instantaneous lateral and / or longitudinal acceleration of the vehicle. This forced response can also be used in combination with, or in place of, the squat motion described above to make the vehicle appear more responsive.

[0043]

[0049] The inventors have recognized through experimentation and analysis that in some embodiments, when there is no, delayed or insufficient roll motion due to, for example, roll suspension with an active suspension system and / or a very stiff passive or semi-active suspension, the driver's perception is that the vehicle is not responsive. Thus, using an active suspension system to maintain the vehicle at substantially zero roll may be counterproductive in terms of perceived vehicle responsiveness. This perception may be due to the absence of roll acceleration of the vehicle in a positive direction, which may impart lateral forces to the driver's side and / or upper body. The driver may perceive a change in pressure on the seat or other surface as an indication of reaction to the driver input.

[0044]

[0050] Experiments were conducted by comparing a vehicle with an active suspension configured to suppress vehicle roll with the same vehicle with an active suspension configured to allow positive vehicle roll. In general, the vehicle with the active suspension configured to allow positive roll was perceived as more responsive. The inventors recognized that in some embodiments, the perception of lateral acceleration can be augmented or replaced by timed roll acceleration introduced by the active suspension system.

[0045]

[0051] In some embodiments, inputs, such as steering and / or pedal commands, are received by a controller in communication with one or more actuators of the active suspension system, which can command certain actuators to apply active forces to the vehicle body in response to the inputs. As used herein, a controller is taken to mean a set of one or more built-in circuits (e.g., a processor), associated software, and / or associated electronic circuitry that can receive one or more input signals and transmit or apply one or more output signals based on the received input signals. In some embodiments, the active suspension system can induce appropriately timed and proportioned movements in response to steering and / or other driver inputs. This reaction can be perceived by the driver and / or other passengers as a "faster" vehicle reaction. Such movements induced by the active suspension system can be used to at least partially compensate for observed or predicted slowness of the vehicle's inherent reaction.

[0046]

[0052] As described in more detail below, in some embodiments, the inherent roll and / or pitch response of the vehicle motion can be induced by lateral and / or longitudinal inertial forces. This inherent response can be modified by one or more active suspension actuators to produce a forced response. These active suspension actuators can be actuated in response to driver input commands that may be provided during a driving maneuver, such as, for example, but not limited to, steering to stay centered in a lane and / or driving to the right or left. In some embodiments, the forces applied by the actuators during the maneuver can be used to modify the driver's perception of the vehicle's responsiveness to steering and / or pedal inputs.

[0047]

[0053] Referring now to FIG. 2, graph 11 represents an example driver steering wheel angle (δ) input for a controlled vehicle for a particular driving condition as a function of time. Graph 12 represents the specific roll angle (φ) response for the controlled vehicle for that particular driving condition as a function of time. Graph 13 represents the specific roll angle (φ) response for the target vehicle for the same driving condition as a function of time. It can be seen that in some embodiments, the final roll angle of the target vehicle (e.g., at 3 seconds in FIG. 2) can be equal to or less than the final roll angle of the controlled vehicle. The target vehicle can correspond to a vehicle having desired reaction characteristics, such as, for example, a vehicle having a smaller yaw inertia or a vehicle having tires with a higher cornering coefficient. Graph 14 represents active forces that can be applied to the controlled vehicle body to increase the roll angle in the positive direction more rapidly at least at the onset of the roll and to produce the forced reaction 15 of the first controlled vehicle. It can be seen that in some embodiments, the forced reaction 15 of the controlled vehicle can be equivalent or identical to the specific reaction 13 of the target vehicle. For the embodiment and operating conditions shown in FIG. 2, the steady-state roll angle achieved by the forced response is equal to the steady-state roll angle achieved by the vehicle's intrinsic response, which may be a desired result in some embodiments to minimize the steady forces output from the active suspension.

[0048]

[0054] In some embodiments, when the controller receives input that the steering wheel has been turned and / or the degree of the turn, the controller can command one or more actuators of the active suspension system to apply a force to reinforce the inherent roll and / or other reaction induced by inertial forces for a period of time. The application of the active force may be stopped (e.g., gradually, abruptly) after a period of time or may be maintained throughout the entire maneuver. In some embodiments and / or driving conditions, the steady-state roll angle of the forced reaction may be greater or less than the steady-state roll angle of the intrinsic reaction. A steady moment may be applied using the active suspension system to maintain a steady-state roll angle for the forced reaction that differs from the steady state of the intrinsic reaction.

[0049]

[0055] As noted above, in some embodiments, one or more of the actuators may be used to apply one or more active forces to the controlled vehicle to produce a desired forced vehicle response. The disclosure is not limited in this respect, and in some embodiments, the active forces may be applied before the start of a maneuver, throughout the entire maneuver, and / or only during a portion of the maneuver. In some embodiments, the active forces may also be deactivated under certain conditions, such as when the amount of heave, pitch, and / or roll is no longer required to be maintained, or when maintaining the heave, pitch, and / or roll is no longer desirable. The active forces may also be deactivated if an undesirable or dangerous situation occurs, such as a situation where an accident is imminent.

[0050]

[0056] In some embodiments, an active suspension system may be used to induce a desired direction and magnitude of vehicle motion to provide a responsive indication before the initiation and / or completion of the vehicle's inherent motion. The ultimate duration, direction and extent of the motion induced by the actuators to enhance the vehicle's perceived response may be equal to or greater than the vehicle's inherent response that would have been achieved without the application of active forces by the active suspension system. During a maneuver involving a turn, the force applied by the active suspension system may, at least initially, induce a roll in a direction away from the direction of the turn (i.e., a positive roll direction). The maneuver may additionally include a fore-aft acceleration, and the induced motion may include a forward pitch.

[0051]

[0057] In some embodiments, the actuators used to apply the one or more active forces may include, but are not limited to, electrohydraulic linear actuators, electromechanical linear actuators, all-linear electric actuators, and / or rotary actuators such as, for example, electromechanical, electrohydraulic, and hydromechanical roll bar actuators. In some embodiments, the active suspension system may include individual actuators located at or near each wheel of the vehicle. In some embodiments, each actuator of the active suspension system may couple each wheel of the vehicle to the vehicle body.

[0052]

[0058] In some embodiments, the vehicle's intrinsic response may be characterized (e.g., predicted, approximated, calculated, simulated) using a vehicle simulation that models the effects of factors including, but not limited to, vehicle and suspension system configuration, vehicle speed, and the particular command given to the vehicle. Alternatively, one or more equations or relationships relating the vehicle's intrinsic response to the command may be used. Additionally or alternatively, the vehicle's intrinsic response may be based at least in part on previously collected and / or calculated data. Additionally or alternatively, the vehicle's intrinsic response may be based on measurements that are not affected by the motion induced by the active suspension, such as, for example, a yaw rate of change sensor or lateral acceleration measured at or near the roll center of the vehicle body.

[0053]

[0059] In some embodiments, the controlled vehicle may have access to a first database stored locally and / or remotely. The first database may be used to define the specific reactions of the desired target vehicle that the controlled vehicle will partially or fully emulate. This first database may include various data of the desired target vehicle. In some embodiments, the first database may include data of multiple target vehicles, and the desired target vehicle may be selected by the vehicle manufacturer, the vehicle owner, the vehicle occupant, the vehicle driver, the mechanic, or any other person authorized to access the vehicle. In some embodiments, the vehicle operator (e.g., the manufacturer, the owner, the vehicle occupant, the vehicle driver, the mechanic, or any other person authorized to access the vehicle) may be presented with various options (e.g., via a display device located on the dashboard of the vehicle), and the operator may be able to select the desired target vehicle whose reactions to emulate.

[0054]

[0060] The information stored in the first database may include, but is not limited to, reaction data of the target vehicle, such as the onset of vehicle roll, pitch and / or heave, the rate of change of vehicle roll, pitch and heave, the acceleration of vehicle roll, pitch and heave, and the front-to-rear distribution of these quantities. The reaction data may be stored as a function of various independent variables, such as, for example, vehicle speed, and for example, steering wheel angle, rate of change of steering wheel angle, brake pedal position, rate of change of brake pedal position, etc.

[0055]

[0061] Additionally or alternatively, the second database may store reaction data defining how the controlled vehicle is likely to react (e.g., in the absence of active forces applied by the suspension system). The specific reaction of the controlled vehicle may also be determined in a number of different ways, including empirically by driving the vehicle under various driving conditions and by collecting data regarding the specific reaction of the vehicle in response to various driver inputs, such as steering commands and / or pedal commands. This reaction information may be collected and stored in the second database without the application of active forces. Additionally or alternatively, the second database may include data characterizing how the controlled vehicle has behaved on past occasions in the absence of active forces and / or data characterizing how the controlled vehicle has behaved on past occasions when active forces are applied by the active suspension system. Information stored in the second database may include, but is not limited to, reaction data of the controlled vehicle, such as the onset of vehicle roll, pitch and / or heave, rates of change of vehicle roll, pitch and heave, acceleration of vehicle roll, pitch and heave, and front-to-rear distribution of these quantities. The reaction data may be stored as a function of various independent variables, such as vehicle speed and a given command, such as steering wheel angle, rate of change of steering wheel angle, brake pedal position, rate of change of brake pedal position, etc. This may include vehicle reaction data collected on previous occasions.

[0056]

[0062] The first database and / or the second database may additionally or alternatively include data regarding other vehicles similar to the controlled vehicle, such as vehicles of the same model. Based on the information stored in the first and / or second databases, actuators of the controlled vehicle may be operated to increase the apparent responsiveness of the controlled vehicle to more closely approximate or emulate the target vehicle. In an embodiment, the first database and the second database may be stored in a non-transitory computer readable memory.

[0057]

[0063] Alternatively or additionally, in an embodiment, a numerical model (e.g., empirically derived model, two-wheeler model, single-track model) of the controlled vehicle and / or the target vehicle, respectively, may be used to determine the specific response of the controlled vehicle and / or the target vehicle. A model of a vehicle (also referred to as a "vehicle model") is taken to mean a set of functions, rules, sequences, or combinations thereof that can define an output response (e.g., body movement) as a function of one or more input commands (e.g., steering commands, acceleration commands, braking commands). Vehicle models such as the above vehicle models may be empirically derived, for example, by performing sweep tests or steering tests, such tests being known to those skilled in the art and described in various ISO (i.e., International Organization for Standardization) standards, including, for example, ISO 7401, ISO 8725, and ISO 8726. The above ISO test procedures are provided as non-limiting examples of tests that can be used to create models of vehicle responses to various commands, the disclosure is not limited thereto, and other tests known to those skilled in the art can be contemplated and used to create these models.

[0058]

[0064] In some embodiments, the above control concepts may be implemented using a two-model approach, detailed below. In this approach, a first model is used to characterize (e.g., predict, approximate, simulate, calculate) the controlled vehicle's response to driver inputs. This model may accept driver inputs (e.g., steering wheel angle, accelerator pedal position, brake pedal position, rate of change of steering wheel position, etc.), vehicle state information (e.g., vehicle speed, vehicle acceleration), vehicle characteristics (e.g., geometry, mass, center of gravity, roll axis), and / or any other parameters that can be used to simulate the controlled vehicle's response. This model may be, for example, a single-track or two-wheeler model.

[0059]

[0065] Similarly, the second model can be used to characterize (e.g., predict, approximate, simulate, calculate) the target vehicle's response to the same or similar driver input. The second vehicle can, for example, respond to the same or similar input and have a faster or more desirable response compared to the intrinsic response of the controlled vehicle under similar or identical driving conditions. For example, the second model can be of a target vehicle having a significantly lower yaw inertia, which can lead to the second model having a faster response to steering or other inputs. In some embodiments, for example, the yaw inertia of the second vehicle can be, for example, about 50% of the yaw inertia of the controlled vehicle. The disclosure is not limited in this respect, and in other embodiments, the yaw inertia of the target vehicle can be, for example, in a range of about 20% to about 90% of the yaw inertia of the controlled vehicle. The output of the first model and the second model can then be used to calculate the difference between the desired "faster response" of the target vehicle and the intrinsic response of the controlled vehicle. This difference can be used to determine a compensatory active force that may need to be applied to the controlled vehicle, for example, by an active suspension system, to approximate, partially or fully emulate, or replicate the target vehicle's motion by the controlled vehicle. In this manner, the first controlled vehicle can be made to roll in a predicted roll direction, for example, as if the vehicle had already experienced sufficient lateral acceleration to cause the roll. By realizing a roll motion before the occurrence of the lateral motion of the vehicle in anticipation of the occurrence of the roll motion, the same responsiveness perception can be created in the driver as the driver would experience in the target vehicle under the same conditions.

[0060]

[0066] As a result, the controlled vehicle may undergo roll, pitch and heave with a direction, rate of change and / or magnitude that may be consistent with well-coordinated and responsive target vehicle motion. This motion may follow one of many patterns that are determined by the industry to be favorably perceived by the vehicle driver or occupants. For example, many passenger cars are built to pitch forward quickly and roll outward quickly (lowering the outside of the vehicle) when turning (i.e., lowering the front end of the vehicle). This combination of pitching forward and rolling outward causes the outside front corner to dip and the perception of the vehicle "leading" into the turn, which is determined to be perceived by the driver as being well-controlled. On the other hand, some manufacturers prefer to build their vehicles so that the front of the vehicle does not dip, or even that the front of the vehicle rises when entering a turn. It is understood that this disclosure does not exclude such motions if such motions are deemed favorable to the vehicle occupants' perception of the vehicle's steering response or on-center steering behavior. In some embodiments, the forced roll, pitch or heave response of the controlled vehicle may be followed, with a slight delay, by a vehicle lateral acceleration and yaw response that is consistent with such roll motion. In some embodiments, the artificial forced response may be perceptually close in amplitude to the final attitude of the vehicle during steady state maneuvering, to make the effect comfortable and non-irritating to the driver.

[0061]

[0067] If the response of a controlled vehicle to a steering input seems disproportionate at first and then settles into a perceptually different attitude, it can create a perception of over-reaction that may be undesirable in that it can make the driver feel that he has less control over the vehicle. If an active suspension system can affect the steady-state attitude of the vehicle in any of the out-of-plane directions of motion (heave, pitch and roll, or any orthogonal combination thereof, such as forward, backward, roll, or left, right, pitch), the final attitude of the vehicle under the action of the active suspension system can be fine-tuned to closely approximate in amplitude and direction the transient forced response.

[0062]

[0068] In some embodiments, if the suspension system is unable to affect the vehicle's steady-state attitude or if it is undesirable to do so (e.g., a suspension system that must expend significant power to do so), the transient forced response may be formed to approximate the final attitude of the controlled vehicle's intrinsic response after the transient forced response is completed.

[0063]

[0069] For example, in some embodiments, the final roll and pitch positions of the controlled vehicle in the absence of active suspension intervention (i.e., the vehicle's intrinsic response) are characterized, and a transient forced response may be created to bring the vehicle to a final roll and pitch position that is the same or similar to the intrinsic response, but at a faster rate of change than would be achieved by the intrinsic response in the absence of any active intervention. In some embodiments, after the controlled vehicle reaches the final roll and pitch positions, the active forces may be gradually reduced so that only the intrinsic response remains. In this way, the driver's perception is of a vehicle that responds to steering inputs to reach the same final attitude, but reaches the intrinsic final attitude much faster than the base vehicle. Thus, as a result of a given maneuver, the controlled vehicle assumes a final attitude that does not feel perceptually different from the final attitude of the intrinsic response vehicle, except that it is achieved more quickly.

[0064]

[0070] The difference in motion between the actual controlled vehicle and a faster modeled target vehicle can be used to create a motion pattern. The inventors have found that by targeting a more responsive target vehicle behavior, a controlled vehicle with active suspension system intervention can be made to feel more responsive than it actually is, while still feeling "realistic" and natural.

[0065]

[0071] As mentioned above, this pattern influences the driver's perception of the vehicle's quality and can therefore be used to fine-tune the desired response. A typical vehicle has three in-plane degrees of freedom (longitudinal, lateral, and yaw) and three out-of-plane degrees of freedom (which can be decomposed into, for example, heave, roll, and pitch).

[0066]

[0072] In some embodiments, the movement pattern may be chosen so that the first corner (e.g., the inner rear corner) of the controlled vehicle does not move vertically, thus reducing the pattern to only two distinct degrees of freedom that can be resolved into roll and pitch about the first corner (e.g., the inner rear corner). This pattern allows the behavior to be fine-tuned by scaling the two degrees of freedom to form a predictable harmonic motion that is comfortable and reassuring to the driver. For example, in FIG. 1 where the vehicle is turning right 9, the vertical movement of the left rear corner 5 can be restricted while the rest of the vehicle rolls in a positive direction about the roll axis 3. As a result, the right rear corner 6 rises and the left front corner 4 sinks.

[0067]

[0073] Using an active suspension system, the instantaneous roll angle of a controlled vehicle can be shifted to produce a desired amount of relative squat or lift of the four corners of the vehicle.

[0068]

[0074] In some embodiments, desired movements of the controlled vehicle may be induced in dynamic driving situations to cause loading and unloading of certain tires. For example, without wishing to be bound by theory, as the vehicle accelerates through a turn, a momentary unloading of that corner can be caused by rolling the vehicle into the front outside corner, and then when the vehicle stops accelerating, the adhesion of the tire at that corner increases significantly. This may be because forces must be applied to the body (e.g., by the suspension) to cause vertical acceleration of the body. Thus, if the body is accelerating toward a tire, this is an indication that that tire may be unloaded. Then, to slow the vertical movement of the body, a force can be applied that is vertically directed to the body that will increase the loading on the tire. In the example pattern described above, where the active suspension accelerates the body vertically toward the front outside corner upon driver input, that corner is initially unloaded and then loaded with a larger force, thereby causing more adhesion. This significantly affects the inside turning response of the vehicle and can be used to create a more dynamic desired response, such as increased traction at the outside front wheel immediately following an initial steering input.

[0069]

[0075] An aspect of some embodiments is the effect on passengers as well as the driver. The perceived responsiveness of the vehicle extends to passengers in a driven or autonomous vehicle. This can have two effects. A passenger who is paying attention to the vehicle's movements and trying to anticipate them may feel as comfortable with the improved responsiveness as the driver, whereas a passenger who is not paying attention to and therefore not expecting any reaction from the vehicle may prefer a vehicle that is perceived as unresponsive by the driver because it equates to less motion input for the unattentive passenger. Thus, the present invention may be used to create an effect that is desirable for the driver in some situations, e.g., when the vehicle is controlled by the driver, and an effect that is desirable for the non-driving passenger in other situations, e.g., when the vehicle is an autonomous or chauffeured vehicle.

[0070]

[0076] This disclosure is applicable not only to cornering and on-center steering, but also to brake and accelerator pedal response, and other functions a driver performs in a vehicle, where the vehicle predicts what the driver expects or prefers as a response from the vehicle in terms of body movements, and provides that response, at least in part, by using active forces in response to driver input.

[0071]

[0077] Figure 3 shows a schematic diagram of a vehicle during a cornering maneuver. In this figure, the vehicle is cornering 301 to the left from the driver's perspective, moving from left to right on the diagram. As is evident from the diagram, in this situation, a passenger vehicle may naturally lean forward (i.e., the front of the vehicle 303 is lower than the rear of the vehicle 305) and roll away (i.e., in this case the right / passenger side 309 of the vehicle is lower than the left / driver side 307). This is a typical behavior for certain well-tuned vehicles, but is also shaped by manufacturer preferences and may not be true for all vehicles. One pattern of movement is not necessarily preferred.

[0072]

[0078] In the example left cornering case shown in Figure 3, normal forces on the tires may increase for the tire on the outside of the turn 311 and decrease for the tire on the inside of the turn (in this case the left / driver side) 313. This effect is commonly referred to as lateral load transfer. There is also a component of force due to acceleration of the vehicle body, which increases the lateral load transfer component.

[0073]

[0079] FIG. 4 shows an example schematic of a simple motorcycle model. The motorcycle model is often referred to as a "single-line" model because it represents the vehicle as if both front wheels were combined as a first single wheel 401 and the rear wheels were combined as a second single wheel 403. The front wheels 401 react to steering angle inputs and the vehicle is represented as having mass and moment of inertia. In some embodiments, the rear wheels 403 may or may not steer, and the disclosure is not limited thereto. The simplest version of this model uses four states to represent the dynamics of the model. Typically these are the lateral acceleration 405, the yaw rate of the vehicle, the lateral velocity, and the yaw angle, but other combinations of states may be chosen and the vehicle always has a constant forward speed. A slightly more complex version of the motorcycle model may have six states including a tire lug parameter representing the low-pass nature of tire force increase, while more complex models may include more than 20 states including roll behavior, engine mass behavior, and other details.

[0074]

[0080] The basic principle of the two-wheeler model is to use forward speed as a steady-state input and to calculate lateral acceleration and yaw rate dynamics as a function of steering angle input 407. Typical parameters required for the vehicle are vehicle mass, yaw moment of inertia, front and rear wheel cornering compliance, geometric information regarding the location of the center of gravity, the desired power point, and the wheelbase of the vehicle.

[0075]

[0081] These two-wheeler models can be improved by using parametric Kalman filtering, using the vehicle's measured lateral acceleration and yaw rate as "correction" signals.

[0076]

[0082] A block diagram of an example of a general algorithm is shown in Figure 5. The main wheel steering angle 501, which is a function of the steering angle measured at the vehicle, the forward speed of the vehicle 503 and an estimate of the road friction coefficient 505 are input to two separate motorcycle model representations 507 and 509. The first motorcycle model 507 represents a model that tracks the approximate specific response of the controlled vehicle, while the second model 509 approximates the specific response of a faster reacting target vehicle, which in some embodiments may have the same or similar steady-state characteristics. The lateral acceleration calculated by the two models is then applied to an algorithm block 511 that calculates the force 513 to be applied to the vehicle body by the active suspension system.

[0077]

[0083] FIG. 6 shows the output of the two models of FIG. 5 in response to a step steering input 61 of 3 degrees of main wheel steering angle (or 3 degrees of angle of the front wheels relative to the longitudinal direction of the vehicle) for a given driving condition. The top plot 60 shows the input steering angle with a step change from an angle of 0 degrees to an angle of 3 degrees at time t=0.2 seconds. The second plot 62 shows two separate traces: the roll angle in degrees (which is a function of lateral acceleration) 63 calculated by the first model simulating the controlled vehicle, and the roll angle in degrees (which is a function of lateral acceleration) 64 calculated by the second, faster-reacting target vehicle model. The bottom plot 65 shows the difference between the two signals in the second plot. As can be seen from these graphs, the real vehicle in this example takes about 350 milliseconds to react to the input and increase the roll angle (or lateral acceleration), whereas the "faster" model increases the roll angle (or lateral acceleration) in only 20 milliseconds in this case. Comparing the two signals, we see a signal that peaks about 20 ms after the input and stabilizes to zero about 500 ms later. In this case, this means that the two models have the same steady-state response as described above. In one embodiment, a controller can command one or more active suspension system actuators to apply one or more active forces over an appropriate time interval to resemble or replicate the target response shown in FIG.

[0078]

[0084] A schematic block diagram of the roll force command algorithm is shown in Figure 7. A model of the controlled vehicle calculates the actual lateral acceleration 701, which can be used for roll and yaw control, for example, in an active suspension vehicle, and a model of the "faster" target vehicle calculates its own lateral acceleration 703. As mentioned above, the two signals are used to calculate a difference signal 705, labeled "DeltaAy". This signal is then used as an input to a pattern algorithm 707, which can also receive additional inputs, such as a scale factor to apply to the pitch component of the pattern 709 and a scale factor to apply to the roll component of the motion pattern 711. The resulting force command is then scaled by an overall gain 713 (used primarily for tunability of the algorithm) and passed through a low pass filter 715 to reduce high frequency noise in the output signal 717.

[0079]

[0085] FIG. 8 shows an example of one embodiment of an algorithm used to calculate a desired movement pattern in response to a given input. In this embodiment described herein, the pattern was modeled such that the inside rear corner of the vehicle is not commanded to move, resulting in only two degrees of freedom of movement of the vehicle scaled by two respective scale factors 801. Because this movement pattern is asymmetric with respect to the input 802 (e.g., when turning left, the left rear corner is not commanded to move vertically, and when turning right, the right rear corner is not commanded to move vertically), the two cases of left and right turns are treated separately. In some embodiments, the input 802 may be, for example, a signal shown in plot 65 of FIG. 6. In some embodiments, the asymmetric reaction can be achieved by separating the two cases using a positive signal saturation block 802 and a negative signal saturation block 803 and taking the sum of the resulting force commands. In some embodiments, a positive input may occur when the predicted movement of the target vehicle is greater than the movement of the controlled vehicle (which may be based on predicted, calculated and / or measured information, for example). Negative inputs occur when the predicted motion of the target vehicle is less than that of the controlled vehicle. Thus, for a positive input, one branch of the calculated forces commands the "positive input pattern" and the other commands nothing, and the resulting sum equals the "positive input pattern." Similar reasoning applies to negative inputs. Note that Figures 5, 7, and 8 were generated using the Simulink tool, a graphical programming environment for modeling dynamic systems. Simulink is a product of MathWorks, Natick, Massachusetts, USA.

Claims

1. 1. A method for controlling a body response of a controlled vehicle, comprising: (a) receiving input from a driver of the controlled vehicle; and (b) inducing motion in the body of the controlled vehicle by modifying an aspect of the response of the body of the controlled vehicle using an active suspension system of the controlled vehicle; the reaction is at least one of roll and pitch; the aspect is at least one of velocity and magnitude; The method, wherein the value of the modified aspect is based at least in part on the input.

2. Modifying the aspect of the response of the body of the controlled vehicle comprises: The method of claim 1 , comprising applying a first force to a body of the controlled vehicle by one or more actuators of an active suspension system of the controlled vehicle.

3. 3. The method of claim 2, wherein the input is a change in steering wheel angle commanding the controlled vehicle to turn in a turning direction selected from the group consisting of a left turn and a right turn, and the first force is a torque that induces a roll away from the turning direction.

4. 3. The method of claim 2, wherein the input is a change in steering wheel angle that commands the controlled vehicle to turn in a turning direction, and the first force includes at least one of (i) an upward force applied to a first corner of a body of the controlled vehicle that is located along an inside of the controlled vehicle, and (ii) a downward force applied to a second corner of a body of the controlled vehicle that is located along an outside of the controlled vehicle.

5. The method of claim 4 , wherein the first force includes both the upward force applied to the first corner and the downward force applied to the second corner.

6. 3. The method of claim 2, wherein the input is a change in brake pedal position commanding the controlled vehicle to brake, and the first force is a torque that causes the front end of the vehicle body to drop vertically relative to the rear end of the vehicle body.

7. 3. The method of claim 2, wherein the input is a change in accelerator pedal position commanding the controlled vehicle to accelerate, and the first force is a torque causing a rear end of the controlled vehicle to lift vertically relative to a front end of the controlled vehicle.

8. The method of claim 2 , wherein the vehicle body has a natural reaction to the input, and the first force has a direction equal to a natural direction of the natural reaction.

9. determining a target response to the input using a first vehicle model; determining a specific response of the controlled vehicle to the input using a second vehicle model; calculating a difference between the intrinsic response and the target response; and determining the aspect of the response of the body of the modified controlled vehicle based at least in part on the calculated difference.

10. The method of claim 2 , wherein the aspect is a rate of change and the response is the roll.

11. The method of claim 2 , wherein the aspect is rate of change and the response is the pitch.

Images