The present disclosure relates generally to chassis-based force nullification systems and methods for seated and standing vehicle occupants. More specifically, the present disclosure relates to chassis-based force nullification systems and methods for seated and standing vehicle occupants that allow the chassis and occupant cell to pivot laterally with respect to a travel plane, such as a road surface, as the vehicle subjects the occupant to lateral and vertical forces. These systems and methods may be passive or active and provide enhanced occupant comfort during vehicular maneuvers, such as curve navigation, in both driver assist and autonomous applications. The systems and methods may be extended conceptually to the nullification of longitudinal forces as well.
A vehicle negotiating a roadway, for example, subjects a vehicle occupant to lateral, longitudinal, and vertical forces. These forces require the occupant to utilize his or her muscles to retain his or her upright posture, potentially resulting in discomfort and/or fatigue over time. Conventional vehicles designed primarily to maintain occupant comfort typically limit lateral and longitudinal accelerations to a maximum of about 0.3 g, allowing them to maintain safe and comfortable driving behavior relative to the surrounding environment and traffic. This is especially true of vehicles operating autonomously. Within this limit, the rigid chassis and occupant cell are designed to allow the occupant, whether seated or standing, to passively achieve a lean angle that balances lateral and/or longitudinal forces while negotiating a curve or hill, for example. Vertical forces are typically accommodated by conventional passive and active suspension systems, well known to those of ordinary skill in the art.
What are still needed in the art, however, are systems and methods that proactively nullify even these lower lateral (and longitudinal) accelerations such that occupant comfort is further enhanced. Such chassis-based force nullification systems and methods are provided by the present disclosure and may operate in a passive or active manner.
In various exemplary embodiments, the present disclosure provides chassis-based force nullification systems and methods for seated and standing vehicle occupants that allow the chassis and occupant cell to pivot laterally with respect to a travel plane, such as a road surface, as the vehicle subjects the occupant to lateral and vertical forces. These systems and methods may be extended conceptually to the nullification of longitudinal forces as well. The systems and methods utilize gravity to, in part, nullify lateral and/or longitudinal occupant accelerations, moving them to intermediate planes between pure lateral and/or longitudinal and pure vertical. Optionally, related to lateral acceleration, the systems and methods could allow the occupant, through the occupant cell and/or chassis, to rotate about a longitudinal pivot such that a resultant of the lateral and gravitational forces aligns with a line drawn between the virtual longitudinal pivot point and the center of mass of the rotatable body. Optionally, related to longitudinal acceleration, the systems and methods could allow the occupant, again through the occupant cell and/or chassis, to rotate about a transverse pivot such that a resultant of the longitudinal and gravitational forces aligns with a line drawn between the virtual transverse pivot point and the center of mass of the rotatable body. Vertical acceleration is dealt with via conventional passive and active suspension system principles, well known to those of ordinary skill in the art.
Although primarily road vehicles (such as cars, trucks, and the like) are used as illustrative examples herein, it will be readily apparent to those of ordinary skill in the art that the systems and methods of the present disclosure are equally applicable to marine, air, space, and other vehicle systems in the broadest sense.
In one exemplary embodiment, the present disclosure provides a system for nullifying one or more of lateral and longitudinal acceleration forces experienced by an occupant of a vehicle in a seated or standing position while the vehicle is traveling along a travel surface, the system including: a chassis structure; and an occupant cell structure one of coupled to and defined by the chassis structure; wherein the chassis structure includes an upper link pivotably coupled to each of a first wheel assembly and a second wheel assembly and the occupant cell and a lower link pivotably coupled to each of the first wheel assembly and the second wheel assembly and the occupant cell; and wherein the upper link and the lower link define a parallelogram and are configured to translate with respect to one another maintaining parallel sides of the parallelogram, thereby leaning the first wheel assembly, the second wheel assembly, and the occupant cell in unison with respect to the travel surface. Optionally, the system is operable for nullifying lateral acceleration forces and the upper link and the lower link are configured to translate transversely with respect to one another maintaining the parallel sides of the parallelogram, thereby leaning the first wheel assembly, the second wheel assembly, and the occupant cell transversely in unison with respect to the travel surface. Each of the first wheel assembly and the second wheel assembly is configured to both lean and rotate with respect to the chassis structure. The occupant cell structure includes one of a seated support and a standing support for an occupant. The occupant cell structure is configured to lean within ±17 degrees from a perpendicular plane with respect to the travel surface. Optionally, the occupant cell structure is configured to lean with active assistance of one or more actuation mechanisms coupled to one or more controllers. Optionally, the occupant cell structure is configured to lean with the active assistance of the one or more actuation mechanisms coupled to the one or more controllers responsive to attitude/inclination feedback from one or more sensors. Alternatively, the occupant cell structure is configured to lean with the active assistance of the one or more actuation mechanisms coupled to the one or more controllers responsive to attitude/inclination feedback from one or more cameras.
In another exemplary embodiment, the present disclosure provides a method for nullifying one or more of lateral and longitudinal acceleration forces experienced by an occupant of a vehicle in a seated or standing position while the vehicle is traveling along a travel surface, the method including: providing a chassis structure; providing an occupant cell structure one of coupled to and defined by the chassis structure; and leaning the occupant cell with respect to the travel surface; wherein the chassis structure includes an upper link pivotably coupled to each of a first wheel assembly and a second wheel assembly and the occupant cell and a lower link pivotably coupled to each of the first wheel assembly and the second wheel assembly and the occupant cell; and wherein the upper link and the lower link define a parallelogram and are configured to translate with respect to one another maintaining parallel sides of the parallelogram, thereby leaning the first wheel assembly, the second wheel assembly, and the occupant cell in unison. Optionally, the method is operable for nullifying lateral acceleration forces and the upper link and the lower link are configured to translate transversely with respect to one another maintaining the parallel sides of the parallelogram, thereby leaning the first wheel assembly, the second wheel assembly, and the occupant cell transversely in unison with respect to the travel surface. Each of the first wheel assembly and the second wheel assembly is configured to both lean and rotate with respect to the chassis structure. The occupant cell structure includes one of a seated support and a standing support for an occupant. The occupant cell structure is configured to lean within ±17 degrees from a perpendicular plane with respect to the travel surface. Optionally, the occupant cell structure is configured to lean with active assistance of one or more actuation mechanisms coupled to one or more controllers. Optionally, the occupant cell structure is configured to lean with the active assistance of the one or more actuation mechanisms coupled to the one or more controllers responsive to attitude/inclination feedback from one or more sensors. Alternatively, the occupant cell structure is configured to lean with the active assistance of the one or more actuation mechanisms coupled to the one or more controllers responsive to attitude/inclination feedback from one or more cameras.
The present disclosure is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like system components/method steps, as appropriate, and in which:
Referring now specifically to
Referring now specifically to
Referring now specifically to
Lean Angle θ(deg)=180/π*tan−1(malat/mg)=180/π*tan−1(alat/g) (1)
This figure shows approximately 1 g of lateral acceleration, giving a lean angle of 45 degrees. This would be required if the goal was related to achieving maximum cornering speed. The goal, however, is typically to achieve maximum comfort. Comfortable driving generates an approximate maximum lateral acceleration of 3.0 m/s2. This gives a lean angle of:
Referring now specifically to
Again, in various exemplary embodiments, the present disclosure provides chassis-based force nullification systems and methods for seated and standing vehicle occupants that allow the chassis and occupant cell to pivot laterally with respect to a travel plane, such as a road surface, as the vehicle subjects the occupant to lateral and vertical forces. These systems and methods may be extended conceptually to the nullification of longitudinal forces as well. The systems and methods utilize gravity to, in part, nullify lateral and/or longitudinal occupant accelerations, moving them to intermediate planes between pure lateral and/or longitudinal and pure vertical. Related to lateral acceleration, the systems and methods allow the occupant, through the occupant cell and/or chassis, to rotate about a longitudinal pivot such that a resultant of the lateral and gravitational forces aligns with a line drawn between the virtual longitudinal pivot point and the center of mass of the rotatable body. Related to longitudinal acceleration, the systems and methods allow the occupant, again through the occupant cell and/or chassis, to rotate about a transverse pivot such that a resultant of the longitudinal and gravitational forces aligns with a line drawn between the virtual transverse pivot point and the center of mass of the rotatable body. Vertical acceleration is dealt with via conventional passive and active suspension system principles, well known to those of ordinary skill in the art.
Although primarily road vehicles (such as cars, trucks, and the like) are used as illustrative examples herein, it will be readily apparent to those of ordinary skill in the art that the systems and methods of the present disclosure are equally applicable to marine, air, space, and other vehicle systems in the broadest sense.
Referring now specifically to
The control of the occupant lean angle achieved by the chassis structure 50 in order to balance the lateral force(s) imposed during traversing a curve may be achieved by several methods. One such method is to allow control to happen naturally by passive means. This necessitates an understanding of how a bicycle or motorcycle accomplishes the same thing. With respect to a bicycle or motorcycle, the rider makes very subtle control inputs in order to execute a turn. The turn is first initiated by the rider creating a slight imbalance in the direction in which he or she wants to go. This can be done by several subtle, almost unconscious actions that either turn the front wheel in the opposite direction and/or distribute some amount of mass in such a way as to overweigh the side in the direction of the turn. As the bicycle or motorcycle then begins to fall in the desired direction, the rider again makes subtle actions to achieve a state of balance in the turn. The geometry of the bicycle or motorcycle's steered wheel is essential in allowing this process to happen naturally. In the leaning chassis structure 50, the occupant 10 is assumed to be sufficiently detached from the process that such subtle actions by him or her are insufficient for adequate control. Thus, a servo mechanism 86 (
Another control method is via a control system designed to respond to changes in lateral force on the occupant cell structure 60 by creating the lean angle required to nullify the lateral force. An acceleration sensor 82 (
Preferably, each wheel 54 is suspended by the upright 74 via some sort of suspension system. This can be in the form of a telescopic fork arrangement, similar to that of a suspended bicycle or motorcycle, or a four-bar linkage (not illustrated) between the steering tube (not illustrated) and the upright 74, or other equivalent suspension arrangement allowing for the vertical displacement of the wheel 54 in response to road surface variations, i.e. bumps. Ideally, to maximize comfort, this suspension is an active one, which proactively lifts the wheel 54 and tire up and sets it down again over these bumps.
Preferably, the active control software application(s) of the present disclosure, when utilized, is/are implemented as coded instructions stored in a memory and executed by a processor. The processor is a hardware device for executing such coded instructions.
The processor can be any custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the memory, a semiconductor-based microprocessor (in the form of a microchip or chip set), or generally any device for executing coded instructions. The processor is configured to execute software stored within the memory, to communicate data to and from the memory, and to generally control operations pursuant to the coded instructions. In an exemplary embodiment, the processor may include a mobile optimized processor, such as one optimized for power consumption and mobile applications. I/O interfaces can be used to receive user input and/or for providing system output. User input can be provided via, for example, a keypad, a touch screen, a scroll ball, a scroll bar, buttons, and/or the like. System output can be provided via a display device, such as a liquid crystal display (LCD), touch screen, and/or the like. The I/O interfaces can also include, for example, a serial port, a parallel port, a small computer system interface (SCSI), an infrared (IR) interface, a radio frequency (RF) interface, a universal serial bus (USB) interface, and/or the like. The I/O interfaces can include a GUI that enables a user to interact with the memory. Additionally, the I/O interfaces may further include an imaging device, i.e. camera, video camera, etc., as described herein.
The memory may include any of volatile memory elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, etc.)), nonvolatile memory elements (e.g., ROM, hard drive, etc.), and combinations thereof. Moreover, the memory may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory may have a distributed architecture, where various components are situated remotely from one another, but can be accessed by the processor. The software in memory can include one or more software programs, each of which includes an ordered listing of executable instructions for implementing logical functions. The software in the memory includes a suitable operating system (O/S) and programs. The operating system essentially controls the execution of other computer programs, and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. The programs may include various applications, add-ons, etc. configured to provide end user functionality. The programs can include an application or “app” which provides various functionalities.
The active suspension alluded to herein may include an active chassis with rear air suspension and “Four-C” technology. Providing comfort and handling advantages while automatically maintaining ride height, it allows a driver/occupant to adapt the chassis to his or her preferences. To ensure comfort and handling even if the vehicle is heavily loaded, the self-adapting air suspension for the rear wheels keeps the ride height constant. “Four-C” technology monitors the vehicle, road, and driver up to 500 times per second, simultaneously adjusting each shock absorber to current road and driving conditions to maximize both ride comfort and driving/riding pleasure. Three chassis settings allow the driver/occupant to adapt the suspension to his or her mood and current road conditions. In “Comfort” mode, the suspension is tuned for maximum comfort, while “Eco” mode optimizes the suspension for low fuel-consumption. “Dynamic” mode enhances the vehicle's sporty characteristics with firmer, more dynamic suspension.
Although the present disclosure is illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure, are contemplated thereby, and are intended to be covered by the following non-limiting claims for all purposes.