Vehicles with steer-by-wire systems having redundant power supplies

Abstract

A vehicle can comprise a steer-by-wire system (18) comprising one or more steering motors (30) configured to turn one or more wheels (34) of the vehicle and one or more electronic control units (94a, 94b) that are each configured to control at least one of the steering motor(s). The vehicle can comprise a first battery (14a) and a DC-to-DC converter (82) having an input (86) and one or more outputs (90a, 90b). The DC-to-DC converter's input can be configured to receive power from the first battery (14a) at a first voltage, and the DC-to-DC converter (82) can be configured to output power through each of the output(s) at a second voltage that is less than the first voltage. The electronic control unit(s) (94a, 94b) can each be configured to receive power from at least one of the DC-to-DC converter's output(s) (90a, 90b) when the steer-by-wire system (18) is in a first state or from a second battery (14b) when the steer-by-wire system is in a second state.

Description

213742-00194VEHICLES WITH STEER-BY-WIRE SYSTEMS HAVING REDUNDANT POWER SUPPLIESFIELD OF INVENTION

[0001] The present invention relates generally to steer-by-wire systems and systems for powering the same.BACKGROUND

[0002] Vehicles such as automobiles often include a steering system to allow a driver to turn one or more of the vehicle’s wheels to steer the vehicle. Steering systems typically comprise a steering wheel coupled to a steering mechanism via a steering column, which can serve as a mechanical linkage through which rotation of the steering wheel can cause at least one of the vehicle’s wheels to turn. However, some vehicles have a steer-by-wire system that lacks such a mechanical linkage. In a steer-by-wire system, a steering wheel can be electrically connected to one or more electronic control units (ECUs) that can receive an input from the steering wheel and control one or more motors based on that input to turn wheels of the vehicle.

[0003] With no steering column, a steer-by-wire system may rely on redundancy to promote safety. One way to increase redundancy is to include multiple batteries whose nominal battery voltages are within the operational voltage range of the steer-by-wire system’s ECU(s), such as multiple 12-volt batteries. Each of such batteries can power the steer-by-wire system, where if a malfunction prevents one of the batteries from providing power to the steer-by-wire system’s ECU(s), another one of the batteries can do so to maintain the steer-by-wire system’s functionality and accordingly allow a driver to steer the vehicle.

[0004] However, the inventors have recognized that such an approach to power redundancy has shortcomings. The use of multiple low-voltage batteries in addition to other power sources of the vehicle — such as a larger, high-voltage battery of an electric vehicle — can introduce complexity into the system design that may be tension with the goal for reliability. Multiple low-voltage batteries can also increase the weight of the vehicle and detract from the space available for vehicle components. And including additional batteries can increase the cost of the vehicle.SUMMARY

[0005] Embodiments of the present vehicles can include a steer-by-wire system with redundancies that can address these shortcomings.213742-00194

[0006] The vehicle’s steer-by-wire system can comprise one or more steering motors configured to turn at least one of the vehicle’s wheels relative to the vehicle’s body and one or more electronic control units (ECUs) configured to control the steering motor(s). To power the steer-by-wire system and one or more other components of the vehicle — such as an electric drive system of the vehicle, if the vehicle is an electric vehicle — the vehicle can comprise a first battery. To meet the requirements of other vehicle component(s) that it powers (e.g., an electric drive system), the first battery may have a first nominal battery voltage that is relatively high, which may accordingly exceed the operational voltage range of the steer-by-wire system’s ECU(s). To allow the first battery to power the ECU(s) of the steer-by-wire system, the steer-by-wire system can comprise a DC-to-DC converter having an input configured to receive power from the first battery at a first voltage and one or more outputs, where the DC-to-DC converter can be configured to output power through each of the output(s) at a second voltage that is less than the first voltage. At least when the steer-by-wire system is in a first state, each of the ECU(s) of the steer-by-wire system can be configured to receive the reduced-voltage power from at least one of the output(s) of the DC-to-DC converter.

[0007] In some embodiments, DC-to-DC converter’s output(s) can comprise first and second outputs and the ECU(s) can comprise first and second ECUs to provide redundancy. The first and second outputs can independently power the first and second ECUs, respectively, where when the steer-by-wire system is in the first state, the first ECU can be configured to receive power from the first output but not from the second output and the second ECU can be configured to receive power from the second output but not from the first output. Thus, if a malfunction prevents one of the outputs from providing power to one of the ECUs, the steer-by-wire system can still function as long as the other of the outputs can provide power to the other of the ECUs.

[0008] Additionally or alternatively, the vehicle can comprise a second, low- voltage battery for redundancy should the ECU(s) be unable to receive power from the DC-to-DC converter. In such embodiments, the steer-by-wire system can be changeable to a second state in which each of the ECU(s) can be configured to receive power from the second battery, thereby allowing the steer-by-wire system to function even if a system failure prevents it from receiving power from the DC-to-DC converter. Because the second battery can have a second nominal battery voltage that is less than the first battery’s first nominal battery voltage and is within an operational voltage range213742-00194of the ECU(s), the voltage of the power from the second battery need not be reduced with a DC-to-DC converter before the ECU(s) receive such power.

[0009] These approaches to redundancy can provide advantages over the use of, for example, two low-voltage batteries. In particular, employing a DC-to-DC converter to permit the first battery to power the steer-by-wire system can allow the vehicle to achieve redundancy without an additional low-voltage battery or, if two power sources are desired, only one additional low-voltage battery. The DC-to-DC converter can be simpler, lighter, more compact, and more cost-effective mechanism for providing power to the steer-by-wire system than an additional low-voltage battery. Utilizing the DC-to-DC converter instead of another low-voltage battery to provide low-voltage power to the steer-by-wire system can thus facilitate weight and space savings for the vehicle as well as reduce the cost of the same.

[0010] Some of the present vehicles comprise a first battery. Some of the present vehicles comprise a second battery. The first battery, in some vehicles, has a first nominal battery volage. The second battery, in some vehicles, has a second nominal battery voltage that is less than the first nominal battery voltage. In some vehicles, the first nominal battery volage is greater than or equal to 300 volts. In some vehicles, the second nominal battery voltage is less than or equal to 20 volts.

[0011] Some vehicles comprise a steer-by-wire system. The steer-by-wire system, in some vehicles, includes a steering input system. The steering input system, in some vehicles, comprises a sensor configured to output a steering control signal. In some vehicles, the steering input system comprises a steering wheel configured to rotate about a rotational axis. In some of such vehicles, the steering control signal depends at least in part on a rotational position of the steering wheel. In some vehicles, the steering input system comprises one or more steering wheel motors configured to exert a torque on the steering wheel in a direction that is substantially parallel to the rotational axis of the steering wheel. The steering input system, in some vehicles, comprises one or more electronic control units, optionally first and second electronic control units, each configured to control at least one of the steering wheel motor(s).

[0012] The steer-by-wire system, in some vehicles, includes a steering control system. The steering control system, in some vehicles, comprises one or more steering motors. The steering motor(s), in some embodiments, are configured to turn one or more wheels of the vehicle relative to a body of the vehicle. In some vehicles, the steering control system comprises one or more213742-00194electronic control units, optionally first and second electronic control units, each configured to control at least one of the steering motor(s) based at least in part on the steering control signal.

[0013] In some vehicles, the steer-by-wire system includes a DC-to-DC converter. In some vehicles, the DC-to-DC converter has an input configured to receive power from the first battery at a first voltage. The first voltage, in some vehicles, is greater than or equal to 300 volts. The DC-to-DC converter, in some vehicles, has one or more outputs that optionally comprise first and second outputs, wherein the DC-to-DC converter is configured to output power through each of the output(s) at a second voltage that is less than the first voltage when the input receives power from the first battery at the first voltage. In some vehicles, the second voltage at which the DC-to-DC converter is configured to output power from each of the output(s) is approximately the same as the second nominal battery voltage. The second voltage, in some vehicles, is less than or equal to 20 volts.

[0014] In some vehicles, the steer-by-wire system has at least a first state in which the electronic control unit(s) of the steering control system are each configured to receive power from at least one of the output(s) of the DC-to-DC converter and / or the electronic control unit(s) of the steering input system are each configured to receive power from at least one of the output(s) of the DC-to-DC converter. In some vehicles where the steering control system comprises first and second electronic control units and the DC-to-DC converter has first and second outputs, when the steer-by-wire system is in the first state, the first electronic control unit of the steering control system is configured to receive power from the first output, optionally at a first receiving voltage, and the second electronic control unit of the steering control system is configured to receive power from the second output, optionally at a second receiving voltage. In some of such vehicles, when the steer-by-wire system is in the first state, the first electronic control unit of the steering control system is not configured to receive power from the second output and the second electronic control unit of the steering control system is not configured to receive power from the first output. In some vehicles where the steering input system comprises first and second electronic control units and the DC-to-DC converter has first and second outputs, when the steer-by-wire system is in the first state, the first electronic control unit of the steering input system is configured to receive power from the first output, optionally at a first receiving voltage, and the second electronic control unit of the steering input system is configured to receive power from the second output, optionally at a second receiving voltage. In some of such vehicles, when the steer-by-wire system is in the213742-00194first state, the first electronic control unit of the steering input system is not configured to receive power from the second output and the second electronic control unit of the steering input system is not configured to receive power from the first output. The second receiving voltage, in some vehicles, is approximately the same as the first receiving voltage. In some vehicles, the first receiving voltage and the second receiving voltage are each between 5 and 20 volts.

[0015] In some vehicles comprising the second battery, the steer-by-wire system is changeable between the first state and a second state in which the electronic control unit(s) of the steering control system are each configured to receive power from the second battery and / or the electronic control unit(s) of the steering input system are each configured to receive power from the second battery. In some vehicles comprising the second battery, when the steer-by-wire system is in the first state, the second battery is configured to receive power from at least one of the output(s) of the DC-to-DC converter. In some vehicles, when the steer-by-wire system is in the first state, the steer-by-wire system is configured to determine when each of the output(s) of the DC-to-DC converter changes from a functioning state in which the DC-to-DC converter is permitted to output power through the output to a non-functioning state in which the DC-to-DC converter cannot output power through the output. For some of such vehicles, the vehicle is configured to change the steer-by-wire system from the first state to the second state when the steer-by-wire system determines that all of the output(s) of the DC-to-DC converter are in the non-functioning state.

[0016] Some vehicles are changeable between a static mode and a dynamic mode. In some vehicles, when the vehicle is in the static mode, power is not permitted to be output from the first battery. In some vehicles, when the vehicle is in the dynamic mode, power is permitted to be output from the first battery.

[0017] The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically; two items that are “coupled” may be unitary with each other. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise. The terms “substantially,” “about,” and “approximately” are each defined as largely but not necessarily wholly what is specified — and include what is specified, e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel — as understood by a person of ordinary skill in the art. As used herein, “substantially parallel” means within 10 degrees of parallel to, and “substantially perpendicular” means within 10 degrees of perpendicular to. In any disclosed213742-00194embodiment, the terms “approximately” and “about” may each be substituted with “within [a percentage] of’ what is specified, where the percentage includes 0.1, 1, 5, and 10 percent.

[0018] The terms “comprise” and any form thereof such as “comprises” and “comprising,” “have” and any form thereof such as “has” and “having,” and “include” and any form thereof such as “includes” and “including” are open-ended linking verbs. As a result, an apparatus or system that “comprises,” “has,” or “includes” one or more elements possesses those one or more elements but is not limited to possessing only those elements. Likewise, a method that “comprises,” “has,” or “includes” one or more steps possesses those one or more steps but is not limited to possessing only those one or more steps.

[0019] Any embodiment of any of the apparatuses, systems, and methods can consist of or consist essentially of — rather than comprise / have / include — any of the described steps, elements, and / or features. Thus, in any of the claims, the term “consisting of’ or “consisting essentially of’ can be substituted for any of the open-ended linking verbs recited above in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.

[0020] Further, an apparatus or system that is configured in a certain way is configured in at least that way, but it can also be configured in other ways than those specifically described.

[0021] The feature or features of one embodiment may be applied to other embodiments, even though not described or illustrated, unless expressly prohibited by this disclosure or the nature of the embodiments.

[0022] Some details associated with the embodiments described above and others are described below.BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers.

[0024] FIG. 1 is a schematic of a one of the present vehicles that includes a steer-by-wire system and one or more systems for redundant powering of the same.

[0025] FIG. 2 is a schematic of communication circuitry of the vehicle of FIG. 1 and illustrates how data is exchanged between different ECUs of the vehicle.213742-00194

[0026] FIGs. 3A and 3B are schematics of power circuitry of the vehicle of FIG. 1 when the steer-by-wire system is in a first state and illustrate how one or more electronic control units (ECUs) of the steer-by-wire system are configured to receive power from a DC-to-DC converter that receives power from a first battery of the vehicle.

[0027] FIGs. 4A and 4B are schematics of the power circuitry of FIGs. 3A and 3B when the steer-by-wire system is in a second state and illustrate how one or more ECUs of the steer-by-wire system are configured to receive power from a second battery of the vehicle.DETAILED DESCRIPTION

[0028] Referring to FIG. 1, shown is an embodiment 10 of the present vehicles, which can be, for example, an automobile. Vehicle 10 can comprise a steer-by-wire system 18 that can be powered by one or more batteries 14a and 14b of the vehicle.

[0029] Steer-by-wire system 18 can allow a driver to turn one or more wheels 34 of vehicle 10 to steer the vehicle. To do so, steer-by-wire system 18 can comprise a steering input system 22 that the driver can interface with and a steering control system 26 that can comprise one or more steering motors 30 configured to turn one or more of wheels 34 relative to vehicle 10’s body. For example, when vehicle 10 comprises at least two front wheels 34 and one or more (e.g., two) rear wheels (e.g., when the vehicle is an automobile), steering motor(s) 30 can be configured to turn the vehicle’s front wheels. Steering motor(s) 30 can do so in any suitable manner. As an illustration, steering control system 26 can comprise a rack 38, steering motor(s) 30 can be configured to translate the rack in a horizontal direction 42, and the translation of the rack can cause wheels 34 that are coupled to the rack to turn relative to the body of vehicle 10.

[0030] Steering control system 26 can comprise a control module 46 configured to control steering motor(s) 30 — and thus the angle at which the steering motor(s) turn at least one of wheels 34 — based at least in part on a steering control signal that a sensor 50 of steering input system 22 is configured to output. For example, steering input system 22 can comprise a steering wheel 54 (e.g., of any suitable shape, such as one comprising a circular outer ring, a yoke, and / or the like) configured to rotate about a rotational axis 58 and the steering control signal that sensor 50 is configured to output can be based at least in part on a rotational position of the steering wheel. In this manner, a driver can rotate steering wheel 54 to cause sensor 50 to output the steering control signal, which can cause steering motor(s) 30 to turn at least one of wheels 34 in a manner reflective of how the steering wheel is rotated (e.g., in the direction that the steering wheel is213742-00194rotated, with more rotation of the steering wheel causing more turning of the wheel(s)). Sensor 50 can optionally comprise a torque and angle sensor such that the steering control signal can further depend at least in part on a torque exerted on steering wheel 54, allowing the forcefulness with which a driver rotates the steering wheel to affect how steering motor(s) 30 rotate at least one of wheels 34. Steer-by-wire system 18 can thus allow driver inputs into steering input system 22 (e.g., via steering wheel 54) to cause turning of at least one of vehicle 10’s wheels 34 without a steering column linking the steering input system and steering control system 26.

[0031] To further facilitate the control of steering motor(s) 30 and their turning of at least one of wheels 34, steering control system 26 can comprise a sensor 62 configured to output — and control module 46 can be configured to receive — a wheel position signal that depends at least in part on a position of at least one of wheels 34. For example, for at least one of wheel(s) 34 that motor(s) 30 are configured to turn, the wheel can be coupled to a steering knuckle that can be configured to pivot about an axis 66, and the wheel position signal that signal 62 outputs can depend at least in part on the pivoted position of the steering knuckle. Control module 46 can be configured to control steering motor(s) 30 further based at least in part on the wheel position signal, which can be indicative of the current wheel position and thus the extent to which at least one of wheels 34 should be turned — if at all — to achieve a wheel position that meets what the steering control signal calls for.

[0032] Steer-by-wire system 18’s steering input system 22 can also include a mechanism for providing feedback to a driver to facilitate the driver’s control of vehicle 10. For example, steering input system 22 can comprise one or more steering wheel motors 74 configured to exert a torque on steering wheel 54 (e.g., in a direction that is substantially parallel to the steering wheel’s rotational axis 58), which can provide force feedback to the driver. To provide the appropriate force feedback, steering input system 22 can comprise a control module 70 configured to control steering wheel motor(s) 74, optionally based at least in part on the steering control signal and / or the wheel position signal. For example, steering input system 22’s control module 70 can cause steering wheel motor(s) 74 to exert a torque on steering wheel 54 in a direction opposite of the direction of rotation of the steering wheel, with the magnitude of the torque being larger when, based on the steering control signal, the control module determines that the steering wheel is at a first rotational position than when the control module determines that the steering wheel is at a213742-00194second rotational position that is closer to a neutral position of the steering wheel than is the first rotational position.

[0033] Steering input system 22’ s control module 70 can be in communication with steering control system 26’ s control module 46, such as via one or more controller area network (CAN) buses. In this manner, control modules 46 and 70 can communicate with one another to facilitate their control of steering motor(s) 30 and steering control motor(s) 74, respectively. As illustration, control module 70 can be configured to receive the steering control signal from sensor 50 and can relay a steering command signal to control module 46 based at least in part on the steering control signal such that steering control system 26’ s control module can control steering motor(s) 30 based at least in part on the steering control signal. Likewise, control module 46 can relay a feedback signal to control module 70 based at least in part on the wheel position signal from sensor 62 such that steering input system 22’ s control module can control steering wheel motor(s) 34 based at least in part on the wheel position signal.

[0034] Steering input system 22’s control module 70 and steering control system 26’s control module 46 can also each be in communication with one or more vehicle electronic control units (ECUs) 78 (e.g., via one or more CAN buses) that can provide additional information for the control of steering wheel motor(s) 74 and / or steering motor(s) 30. For example, control module 46 and / or control module 70 can be configured to receive a vehicle speed signal from at least one of ECU(s) 78 that is based at least in part on a speed of vehicle 10, and the control modules can be configured to control steering motor(s) 30 and / or steering wheel motor(s) 74, respectively, further based at least in part on the vehicle speed signal. This can allow steer-by-wire system 18 to facilitate maneuverability by adjusting, based at least in part on vehicle 10’s speed, the manner in which steering motor(s) 30 turn at least one of wheels 34 in response to a driver input. As an illustration, when vehicle 10 travels at a first speed, movement of steering wheel 54 from the neutral position to a particular rotational position can cause steering motor(s) 30 to turn at least one of wheels 34 by a larger amount compared to when the vehicle travels at a second speed that is faster than the first speed, which can allow a user to perform tight turns (e.g., for a U-turn or parking) at slow speeds with less rotation of the steering wheel. As another example, at least one of ECU(s) 78 can issue one or more command signals to control module 46 and / or control module 70 to cause steering motor(s) 30 to turn at least one of wheels 34 and / or steering wheel213742-00194motor(s) 74 to rotate steering wheel 54, respectively, for advanced driver-assistance system (ADAS) functionality, including autonomous navigation of vehicle 10.

[0035] Communication between vehicle ECU(s) 78 and control module 46 and between the vehicle ECU(s) and control module 70 can also allow one or more of the vehicle ECU(s) to receive information from steer- by- wire system 18 to facilitate control of vehicle 10, provide system notifications, and / or the like. For example, when one or more components of steer-by-wire system 18 malfunction, a signal can be communicated to at least one of vehicle ECU(s) 78 to generate a notification regarding the malfunction on a human-machine interface (HMI) of vehicle 10.

[0036] Referring additionally to FIG. 2, control module 46 of steering control system 26 can comprise one or more ECUs 94a and 94b and control module 70 of steering input system 22 can comprise one or more ECUs 98a and 98b. ECU(s) 94a and 94b of steering control system 26’ s control module 46 can provide the above-described control of steering motor(s) 30, with each of such ECU(s) being configured to control at least one (up to and including each) of the steering motor(s) based at least in part on the steering control signal and, optionally, one or more other signals (e.g., the wheel position signal and / or the vehicle speed signal) as discussed above. And ECU(s) 98a and 98b of steering input system 22’s control module 70 can provide the abovedescribed control of steering wheel motor(s) 74, with each of such ECU(s) being configured to control at least one (up to and including each) of the steering wheel motor(s) (e.g., based at least in part on the steering control signal, the wheel position signal, and / or the vehicle speed signal) as also discussed above.

[0037] With no steering column between steering input system 22 and steering control system 26, redundancy can be especially important to allow a driver to continue to steer vehicle 10 should one or more of the electronic components of steer-by-wire system 18 fail. In some embodiments, to achieve such redundancy, ECU(s) 94a and 94b of steering control system 26’s control module 46 can include first and second ECUs 94a and 94b and ECU(s) 98a and 98b of steering input system 22’s control module 70 can include first and second ECUs 98a and 98b. And, preferably, steering motor(s) 30 comprise at least two steering motors that can each be controlled by a respective one of ECUs 94a and 94b and steering wheel motor(s) 74 comprise at least two steering wheel motors that can each be controlled by a respective one of ECUs 98b. First ECU 94a of steering control system 26 and first ECU 98a of steering input system 22 can provide213742-00194primary control of wheels 34 (e.g., by controlling a first one of steering motors 30) and steering wheel 54 (e.g., by controlling a first one of steering wheel motors 74), respectively, while second ECU 94b of the steering control system and second ECU 98b of the steering input system can provide backup control of the wheels (e.g., by controlling a second one of the steering motors) and steering wheel (e.g., by controlling a second one of the steering wheel motors), respectively, if one or both of the first ECUs becomes non-operational (e.g., due to a power supply failure). With this redundant configuration, the above-described communication between control modules 46 and 70 can be between their respective first ECUs 94a and 98a and second ECUs 94b and 98b, e.g., with the first ECU of steering control system 26 configured to communicate with the first ECU (but not the second ECU) of steering input system 22 (e.g., via a first private CAN bus 72a) and the second ECU of the steering control system configured to communicate with the second ECU (but not the first ECU) of the steering input system (e.g., via a second private CAN bus 72b). And to further promote redundancy, first ECUs 94a and 98a of steering control system 26 and steering input system 22, respectively, can each be in communication with vehicle ECU(s) 78 via a first CAN bus 76a while second ECUs 94b and 98b of the steering control system and steering input system, respectively, can each be in communication with the vehicle ECU(s) via a second CAN bus 76b that is different than the first CAN bus. Additionally, for each of control modules 46 and 70, first and second ECUs (e.g., 94a and 94b or 98a and 98b, respectively) of the module can be in communication via a private CAN bus 80 to allow the communication of information therebetween (e.g., regarding ECU status, such as if one of the ECUs is not operational).

[0038] As noted above, steer-by-wire system 18 can be powered by one or more batteries 14a and 14b of vehicle 10, which can include at least a first battery 14a. In particular, control module 46 and control module 70 — and thus their ECUs 94a, 94b, 98a, and 98b — can each be configured to receive power that originated from at least one of vehicle 10’s one or more batteries 14a and 14b, and the control modules (e.g., the ECUs thereof) can convey power to and thereby drive steering motor(s) 30 or steering wheel motor(s) 74, respectively. However, at least one of vehicle 10’s one or more batteries 14a and 14b can have a nominal battery voltage that falls outside of a voltage range that control module 46 and control module 70 may each be configured to operate at. For example, vehicle 10 preferably comprises an electric vehicle whose first battery 14a has a first nominal battery voltage that is relatively high — such as greater than or equal to any one of, or between any two of, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, or 800213742-00194volts — such that the first battery can meet the requirements of and thus power the vehicle’s electric drive system, while control module 46 and control module 70 — and their ECUs 94a, 94b, 98a, and 98b — can each be configured to operate at a relatively low voltage, such as a voltage that is less than or equal to any one of, or between any two of, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 6, or 5 volts (e.g., between 5 and 20 volts, such as between 9 and 16 volts). To allow high-voltage first battery 14a to power low-voltage control module 46 and / or control module 70, steer-by-wire system 18 can further comprise a DC-to-DC converter 82.

[0039] Referring additionally to FIGs. 3A and 3B, DC-to-DC converter 82 can have an input 86 and one or more — optionally two or more — outputs 90a and 90b. Input 86 of DC-to-DC converter 82 can be configured to receive power 114 from first battery 14a at a first voltage, and the DC-to-DC converter can be configured to output power 118 through each of its output(s) 90a and 90b at a second voltage that is less than the first voltage when its input receives power from the first battery at the first voltage (FIG. 3B). For example, the first voltage at which input 86 of DC-to-DC converter 82 is configured to receive power 114 from first battery 14a can be approximately the same as the first battery’s first nominal battery voltage, such as greater than or equal to any one of, or between any two of, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, or 800 volts, and the second voltage at which the DC-to-DC converter is configured to output power from each of output(s) 90a and 90b can be within the operational voltage range of control modules 46 and 70 (and of their ECUs 94a, 94b, 98a, and 98b), such as less than or equal to any one of, or between any two of, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 6, or 5 volts (e.g., between 5 and 20 volts, such as between 9 and 16 volts). In this manner, DC-to-DC converter 82 can reduce the voltage of power received from first battery 14a to a voltage at which control modules 46 and 70 can operate. Additionally, DC-to-DC converter 82 can be configured to output an adequate amount of power 118 for powering steer-by-wire system 18; for example, the DC-to-DC converter can be configured to output greater than or equal to any one of, or between any two of, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 2.25, or 2.5 kilowatts of power through each of its output(s) 90a and 90b when receiving power from first battery 14a.

[0040] When steer-by-wire system 18 is in the state shown — which can be a first state of the steer-by-wire system — ECU(s) 94a and 94b of steering control system 26 and ECU(s) 98a and 98b of steering input system 22 can each be configured to receive power 118 from at least one of output(s) 90a and 90b of DC-to-DC converter 82 at a receiving voltage that can be approximately213742-00194the same as the second voltage at which the DC-to-DC converter outputs the power (e.g., less than or equal to any one of, or between any two of, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 6, or 5 volts, such as between 5 and 20 volts or between 9 and 16 volts). And, to further promote redundancy for steer-by-wire system 18, DC-to-DC converter 82 can comprise first and second outputs 90a and 90b when control module 46 comprises first and second ECUs 94a and 94b and when control module 70 comprises first and second ECUs 98a and 98b. In particular, first and second outputs 90a and 90b of DC-to-DC converter 82 can independently provide power to first ECUs 94a and 98a and second ECUs 94b and 98b, respectively, wherein the first ECU of steering control system 26 and the first ECU of steering input system 22 can each be configured to receive power 118 from the first output but not from the second output and the second ECU of the steering control system and the second ECU of the steering input system can each be configured to receive power from the second output but not from the first input. The receiving voltage at which first ECUs 94a and 98a receive power 118 can be approximately the same as the receiving voltage at which second ECUs 94b and 98b receive power. With such independent outputs 90a and 90b, if one of the outputs is in a non-functioning state in which DC-to-DC converter 82 cannot output power therethrough, the DC-to-DC converter can still power one of ECUs 94a and 94b of steering control system 26 and one of ECUs 98a and 98b of steering input system 22 through the other of the outputs as long as the other output is in a functioning state. Steer-by-wire system 18 can thus still allow a driver to steer vehicle 10 when one of outputs 90a and 90b of DC-to-DC converter 82 is in a non-functioning state.

[0041] In some embodiments, vehicle 10 can provide redundancy for steer-by-wire system 18 by also comprising a second battery 14b that can serve as another power source for the steer-by-wire system. While ECU(s) 94a and 94b of steering control system 26 and ECU(s) 98a and 98b of steering input system 22 can each be configured to receiver power 118 from at least one of output(s) 90a and 90b of DC-to-DC converter 82 when steer-by-wire system 18 is in the first state, referring additionally to FIGs. 4A and 4B, the steer-by-wire system can be changeable to a second state in which the ECU(s) of the steering control system and the ECU(s) of the steering input system are each configured to receive power from second battery 14b instead of from the DC-to-DC converter. Second battery 14b can be a backup power source for steer-by-wire system 18 should a malfunction prevent DC-to-DC converter 82 from providing power to control modules 46 and 70 (and thus ECU(s) 94a and 94b and ECU(s) 98a and 98b), including if the malfunctionP0004.WQ213742-00194prevents the DC-to-DC converter from receiving power 114 from first battery 14a, is a malfunction of the DC-to-DC converter itself, or is a malfunction that prevents power 118 from each of the DC-to-DC converter’s output(s) 90a and 90b from reaching the control modules and their ECUs. For example, steer- by- wire system 18, when in the first state, can be configured to determine when each of output(s) 90a and 90b changes from a functioning state in which the DC-to-DC converter is permitted to output power through the output to a non-functioning state in which the DC-to-DC converter cannot output power through the output (e.g., via voltage sensor(s) and / or current sensor(s) of the DC-to-DC converter and / or the like), and vehicle 10 can be configured to change the steer-by-wire system from the first state to the second when the steer-by-wire system determines that all of the output(s) of the DC-to-DC converter are in the non-functioning state. As shown, to do so, vehicle 10 can comprise one or more primary switches 102 and one or more secondary switches 106, the primary and secondary switches each being changeable between an open state in which current is not permitted to flow through the switch and a closed state in which current is permitted to flow through the switch. When steer-by-wire system 18 is in the first state (FIGs. 3 A and 3B), primary switch(es) 102 can each be in the closed state and secondary switch(es) 106 can each be in the open state such that control modules 46 and 70 — and thus ECU(s) 94a and 94b and ECU(s) 98a and 98b — are each in electrical communication with at least one of output(s) 90a and 90b of DC-to-DC converter 82 but not with second battery 14b. In some embodiments, when steer-by-wire system 18 is in the first state, second battery 14b can be configured to receive power from at least one of the output(s) of the DC-to-DC converter. When steer-by-wire system 18 is changed from the first state to the second state (FIGs. 4A and 4B), primary switch(es) 102 can each be changed to the open state and secondary switch(es) 106 can each be changed to the closed state such that control modules 46 and 70 — and thus ECU(s) 94a and 94b and ECU(s) 98a and 98b — are each in electrical communication with second battery 14b but not with output(s) 90a and 90b of DC-to-DC converter 82. This redundancy allows steer-by-wire system 18 to operate even when a malfunction prevents the steer-by-wire system from operating on power from first battery 14a and DC-to-DC converter 82.

[0042] Unlike first battery 14a, second battery 14b can be a low- voltage battery such that the voltage of power 118 it provides to steer-by-wire system 18 need not be reduced with another DC-to-DC converter. That is, second battery 14b can have a second nominal battery voltage that is less than the first nominal battery voltage of first battery 14a, such as a second nominal battery213742-00194voltage that is less than or equal to any one of, or between any two of, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 6, or 5 volts (e.g., between 5 and 20 volts, such as between 9 and 16 volts or about 12 volts), which can be within the operational voltage range of control modules 46 and 70 (and thus of their ECU(s) 94a and 94b and ECU(s) 98a and 98b). And second battery Mb’s second nominal battery voltage can be approximately the same as the second voltage at which DC-to-DC converter 82 is configured to output power 118 from each of its output(s) 90a and 90b, which can promote consistency by allowing ECU(s) 94a and 94b and ECU(s) 98a and 98b to receive power at approximately the same voltage when steer-by-wire system 18 is in the first and second states.

[0043] Second battery 14b, as a backup to first battery 14a that need not power components of vehicle 10 with a high energy demand (like an electric drive system thereof), can also have a lower capacity than the first battery to promote compactness and reduce cost. For example, while first battery 14a can have a capacity that is greater than or equal to any one of, or between any two of, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 kWh (e.g., at least 40 kWh), second battery 14b can have a capacity that is less than or equal to any one of, or between any two of, 2.0, 1.8, 1.6, 1.4, 1.2, 1.0, 0.8, 0.6, 0.4, or 0.2 kWh. The capacity of second battery 14b, while lower than that of first battery 14a, can still be sufficient to power steer-by-wire system 18 for enough time for a driver reach a safe area in the event that the steer-by-wire system can no longer be powered by first battery 14a and DC-to-DC converter 82.

[0044] Achieving power redundancy through high-voltage first battery 14a with DC-to-DC converter 82 and low-voltage second battery 14b can provide advantages over the conventional approach of employing two low-voltage batteries for power redundancy. In particular, because vehicle 10 may require first battery 14a to power other components thereof (e.g., its electric drive system), allowing that already-required first battery to power steer-by-wire system 18 through the use of DC-to-DC converter 82 with second battery 14b as a backup permits power redundancy to be achieved without a third battery and the components (e.g., wiring, harnesses, and / or the like) needed to connect the third battery to the steer-by-wire system. DC-to-DC converter 82 can be a simpler and thus more reliable mechanism for powering steer-by-wire system 18 than a third low-voltage battery, especially when it conveys power from a battery that is also responsible for powering the vehicle’s drive system, as such batteries tend to be engineered for greater reliability and longevity than typical low-voltage (e.g., 12-volt) batteries. And DC-to-DC converter 82 can be lighter and more compact than a third battery that has a capacity suitable for powering steer-213742-00194by- wire system 18, which can thus facilitate weight savings for vehicle 10 and promote the efficient use of space for components of the vehicle. Additionally, DC-to-DC converter 82 can be more cost-effective than a third low-voltage battery, which can promote cost savings.

[0045] The inclusion of a second battery 14b can, in addition to providing power redundancy for steer-by-wire system 18, facilitate vehicle start-up. For example, when vehicle 10 is static and not being driven (e.g., while parked and stationary for at least a threshold amount of time), its first battery 14a preferably is not in electrical communication with the vehicle components that it powers when the vehicle is in use, which can facilitate battery preservation, mitigate the risk of unintended powering of components and / or theft, and / or the like. Vehicle 10 can thus have a static mode in which power is not permitted to be output from first battery 14a. When vehicle 10 is in the static mode, second battery 14b can still provide power to one or more components of the vehicle such that at least some vehicle functionality — including that required for vehicle entry and start-up — is enabled before the vehicle is changed to a dynamic mode in which power is permitted to be output from the first battery and the vehicle can be driven. The component(s) that can receive power from second battery 14b when vehicle 10 is in the static mode can include steer-by-wire system 18, including the steer-by-wire system’s control modules 46 and 70 (and thus ECU(s) 94a and 94b and ECU(s) 98a and 98b) (e.g., the steer-by-wire system can be in the second state when the vehicle is in the static mode). Accordingly, a driver can turn at least one of wheels 34 of vehicle 10 when the vehicle is in the static mode and before the vehicle enters the dynamic mode for driving.

[0046] Because vehicle 10’s one or more batteries 14a and 14b can output a relatively large amount of power, the vehicle can comprise one or more fuses 110 to protect electrical components of steer-by-wire system 18 should a malfunction cause the steer-by-wire system to receive an amount of power that could damage such components. Fuse(s) 110 can be arranged such that, for each of ECU(s) 94a and 94b of steering control system 26 and ECU(s) 98a and 98b of steering input system 22, power 118 received by the ECU (e.g., from at least one of output(s) 90a and 90b or from second battery 14b) must past through at least one of the fuse(s) before reaching the ECU.

[0047] The above specification and examples provide a complete description of the structure and use of illustrative embodiments. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without213742-00194departing from the scope of this invention. As such, the various illustrative embodiments of the products, systems, and methods are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and embodiments other than the one shown may include some or all of the features of the depicted embodiment. For example, elements may be omitted or combined as a unitary structure, and / or connections may be substituted. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and / or functions, and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments.

[0048] The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase(s) “means for” or “step for,” respectively.

Claims

213742-00194CLAIMS1. A vehicle comprising:first and second batteries, wherein:the first battery has a first nominal battery voltage; andthe second battery has a second nominal battery voltage that is less than the first nominal battery voltage; anda steer-by-wire system including:a steering input system that comprises a sensor configured to output a steering control signal;a steering control system comprising:one or more steering motors that are configured to turn one or more wheels of the vehicle relative to a body of the vehicle; andone or more electronic control units, each configured to control at least one of the steering motor(s) based at least in part on the steering control signal; anda DC-to-DC converter having:an input configured to receive power from the first battery at a first voltage;andone or more outputs, wherein the DC-to-DC converter is configured to output power through each of the output(s) at a second voltage that is less than the first voltage when the input receives power from the first battery at the first voltage;wherein the steer-by-wire system is changeable between:a first state in which the electronic control unit(s) of the steering control system are each configured to receive power from at least one of the output(s) of the DC-to-DC converter; anda second state in which the electronic control unit(s) of the steering control system are each configured to receive power from the second battery.213742-001942. The vehicle of claim 1, wherein:the one or more outputs of the DC-to-DC converter comprise first and second outputs; the one or more electronic control units of the steering control system comprise first and second electronic control units; andwhen the steer-by-wire system is in the first state:the first electronic control unit of the steering control system is configured to receive power from the first output and is not configured to receive power from the second output; andthe second electronic control unit of the steering control system is configured to receive power from the second output and is not configured to receive power from the first output.

3. The vehicle of claim 2, wherein when the steer-by-wire system is in the first state:the first electronic control unit of the steering control system is configured to receive power from the first output at a first receiving voltage and the second electronic control unit of the steering control system is configured to receive power from the second output at a second receiving voltage that is approximately the same as the first receiving voltage.

4. The vehicle of claim 3, wherein the first receiving voltage and the second receiving voltage are each between 5 and 20 volts.213742-001945. The vehicle of any one of claims 1-4, wherein the steering input system comprises:a steering wheel configured to rotate about a rotational axis, wherein the steering control signal depends at least in part on a rotational position of the steering wheel; one or more steering wheel motors configured to exert a torque on the steering wheel in a direction that is substantially parallel to the rotational axis of the steering wheel; andone or more electronic control units, each configured to control at least one of the steering wheel motor(s);wherein:when the steer-by-wire system is in the first state, the electronic control unit(s) of the steering input system are each configured to receive power from at least one of the output(s) of the DC-to-DC converter; and when the steer-by-wire system is in the second state, the electronic control unit(s) of the steering input system are each configured to receive power from the second battery.

6. The vehicle of claim 5, wherein:the one or more outputs of the DC-to-DC converter comprise first and second outputs; the one or more electronic control units of the steering input system comprise first and second electronic control units; andwhen the steer-by-wire system is in the first state:the first electronic control unit of the steering input system is configured to receive power from the first output and is not configured to receive power from the second output; andthe second electronic control unit of the steering input system is configured to receive power from the second output and is not configured to receive power from the first output.P0004.WQ213742-001947. The vehicle of claim 6 wherein when the steer-by-wire system is in the first state:the first electronic control unit of the steering input system is configured to receive power from the first output at a first receiving voltage and the second electronic control unit of the steering input system is configured to receive power from the second output at a second receiving voltage that is approximately the same as the first receiving voltage.

8. The vehicle of claim 7, wherein the first receiving voltage and the second receiving voltage are each between 5 and 20 volts.

9. The vehicle of any of claims 1-8, wherein the second voltage at which the DC-to-DC converter is configured to output power from each of the output(s) is approximately the same as the second nominal battery voltage.

10. The vehicle of any one of claims 1-9, wherein when the steer-by-wire system is in the first state, the second battery is configured to receive power from at least one of the output(s) of the DC-to-DC converter.

11. The vehicle of any one of claims 1-10, wherein the vehicle is changeable between:a static mode in which power is not permitted to be output from the first battery; and a dynamic mode in which power is permitted to be output from the first battery.

12. The vehicle of any one of claims 1-11, wherein :the first nominal battery voltage and the first voltage at which the input of the DC-to-DC converter is configured to receive power from the first battery are each greater than or equal to 300 volts; andthe second nominal battery voltage and the second voltage at which the DC-to-DC converter is configured to output power from each of the output(s) are each less than or equal to 20 volts.213742-0019413. The vehicle of any one of claims 1-12, whereinwhen the steer-by-wire system is in the first state, the steer-by-wire system is configured to determine when each of the output(s) of the DC-to-DC converter changes from a functioning state in which the DC-to-DC converter is permitted to output power through the output to a non-functioning state in which the DC-to-DC converter cannot output power through the output; andthe vehicle is configured to change the steer-by-wire system from the first state to the second state when the steer-by-wire system determines that all of the output(s) of the DC-to-DC converter are in the non- functioning state.213742-0019414. A vehicle comprising:a first battery; anda steer-by-wire system including:a steering input system that comprises a sensor configured to output a steering control signal;a steering control system comprising:one or more steering motors that are configured to turn one or more wheels of the vehicle relative to a body of the vehicle; andfirst and second electronic control units, each configured to control at least one of the steering motor(s) based at least in part on the steering control signal; anda DC-to-DC converter having:an input configured to receive power from the first battery at a first voltage;andfirst and second outputs, wherein the DC-to-DC converter is configured to output power through each of the outputs at a second voltage that is less than the first voltage when the input receives power from the first battery at the first voltage;wherein the steer-by-wire system has at least a first state in which:the first electronic control unit of the steering control system is configured to receive power from the first output and is not configured to receive power from the second output; andthe second electronic control unit of the steering control system is configured to receive power from the second output and is not configured to receive power from the first output.

15. The vehicle of claim 14, wherein when the steer-by-wire system is in the first state:the first electronic control unit of the steering control system is configured to receive power from the first output at a first receiving voltage and the second electronic control unit of the steering control system is configured to receive power from the second output at a second receiving voltage that is approximately the same as the first receiving voltage.213742-0019416. The vehicle of claim 15, wherein the first receiving voltage and the second receiving voltage are each between 5 and 20 volts.

17. The vehicle of any one of claims 14-16, wherein the steering input system comprises: a steering wheel configured to rotate about a rotational axis, wherein the steering control signal depends at least in part on a rotational position of the steering wheel; one or more steering wheel motors configured to exert a torque on the steering wheel in a direction that is substantially parallel to the rotational axis of the steering wheel; andfirst and second electronic control units, each configured to control at least one of the steering wheel motor (s);wherein when the steer-by-wire system is in the first state:the first electronic control unit of the steering input system is configured to receive power from the first output and is not configured to receive power from the second output; andthe second electronic control unit of the steering input system is configured to receive power from the second output and is not configured to receive power from the first output.

18. The vehicle of claim 17, wherein when the steer-by-wire system is in the first state:the first electronic control system of the steering control system and the first electronic control unit of the steering input system are each configured to receive power from the first output at a first receiving voltage; andthe second electronic control unit of the steering control system and the second electronic control unit of the steering input system are each configured to receive power from the second output at a second receiving voltage that is approximately the same as the first receiving voltage.213742-0019419. The vehicle of claim 18, wherein the first receiving voltage and the second receiving voltage are each between 5 and 20 volts.

20. The vehicle of any one of claims 14-19, wherein :the first battery has a first nominal battery voltage;the first nominal battery voltage and the first voltage at which the input of the DC-to-DC converter is configured to receive power from the first battery are each greater than or equal to 300 volts; andthe second voltage at which the DC-to-DC converter is configured to output power from each of the first and second outputs is less than or equal to 20 volts.

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