Patent Description:
Document <CIT> describes a system for managing suspension pressure and tyre pressure dependent on dynamic vehicle load.

It is an object of the invention to provide an improved system better adapted for agricultural vehicles.

This object is achieved by a system as defined in claim <NUM>. Preferred aspects are covered by the dependent claims.

One embodiment relates to a system that includes a hydraulic suspension system including a front suspension actuator, and a front suspension pressure sensor associated with the front suspension actuator; a tire inflation system; and one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: determine a dynamic weight based on information received from the front suspension pressure sensor of the hydraulic suspension system, determine a current front axle lead ratio based on the dynamic weight, determine a target front axle lead ratio, and control operation of the tire inflation system to adjust from the current front axle lead ratio to the target front axle lead ratio.

Another embodiment relates to a system that includes one or more processing circuits comprising one or more memory devices coupled to one or more processors, the one or more memory devices configured to store instructions thereon that, when executed by the one or more processors, cause the one or more processors to: determine a dynamic weight based on information received from a suspension pressure sensor associated with a suspension actuator of a hydraulic suspension system, determine a rolling radius of a tire supported by the suspension actuator based on the dynamic weight, determine a current axle lead ratio based on the rolling radius, determine a target axle lead ratio, determine a target tire pressure change of the tire to adjust the current axle lead ratio to the target axle lead ratio, and control operation of a tire inflation system to implement the target tire pressure change.

An example not covered by the claims, but useful for understanding the invention, relates to a method that includes determining a dynamic weight based on information received from a suspension pressure sensor associated with a suspension actuator of a hydraulic suspension system, querying a lookup table using the dynamic weight and a current tire pressure received from a tire pressure sensor associated with a tire, returning a current rolling radius of the tire from the lookup table, determining a current axle lead ratio based on the returned current rolling radius, determining a target axle lead ratio, querying the lookup table using the dynamic weight and a target rolling radius associated with the target axle lead ratio, returning a target tire pressure of the tire from the lookup table, determining a target tire pressure change based on a target tire pressure and the current tire pressure to adjust the current axle lead ratio to the target axle lead ratio, and controlling operation of a tire inflation system to implement the target tire pressure change.

This summary is illustrative only and is not intended to be in any way limiting the scope of the invention as defined by the appended claims. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.

Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present invention as defined by the appended claims is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology used herein is for the purpose of description only and should not be regarded as limiting.

According to an exemplary embodiment, a vehicle (e.g., a tractor) of the present disclosure includes front wheel and rear wheels, a hydraulic suspension system, and a central tire inflation system. A controller is structured to determine a current front axle lead ratio based on dynamic loading of the vehicle (e.g., during operation), and adjust tire pressures of front tires mounted on the front wheels and rear tires mounted on the rear wheels to achieve a target front axle lead ratio. Dynamic loading of the vehicle (e.g., while towing an implement) may result in a dynamic weight shift and an increased dynamic weight on the rear tires. The increased dynamic weight results in a reduced rolling radius of the rear tires and an increased front axle lead ratio. A front axle lead ratio larger than the target front axle lead ratio can result in increased front wheel slippage, increased rear wheel drag, and an overall decrease in tractive efficiency of the vehicle. Adjustment of the tire pressures can affect the tire rolling radius and therefore be used to control the front axle lead ratio and improve the tractive efficiency of the vehicle.

According to the exemplary embodiment shown in <FIG>, a machine or vehicle, shown as vehicle <NUM>, includes a chassis, shown as frame <NUM>; a body assembly, shown as body <NUM>, coupled to the frame <NUM> and having an occupant portion or section, shown as cab <NUM>; operator input and output devices, shown as operator interface <NUM>, that are disposed within the cab <NUM>; a drivetrain, shown as driveline <NUM>, coupled to the frame <NUM> and at least partially disposed under the body <NUM>; a vehicle braking system, shown as braking system <NUM>, coupled to one or more components of the driveline <NUM> to facilitate selectively braking the one or more components of the driveline <NUM>; a vehicle suspension <NUM> coupled between the frame <NUM> and one or more components of the driveline <NUM> (e.g., tractive elements <NUM> and <NUM> discussed below) to facilitate the dampening of vibrations during travel of the vehicle <NUM>, level the vehicle <NUM>, raise/lower the vehicle <NUM>, or adjust the orientation or alignment of the vehicle <NUM> to the ground; a pneumatic system <NUM> coupled to the frame <NUM> and structured to provide pressurized air to the vehicle <NUM>; and a vehicle control system, shown as control system <NUM>, coupled to the operator interface <NUM>, the driveline <NUM>, the braking system <NUM>, the suspension <NUM>, and the pneumatic system <NUM>. In other embodiments, the vehicle <NUM> includes more or fewer components.

According to an exemplary embodiment, the vehicle <NUM> is an off-road machine or vehicle. In some embodiments, the off-road machine or vehicle is an agricultural machine or vehicle such as a tractor, a telehandler, a front loader, a combine harvester, a grape harvester, a forage harvester, a sprayer vehicle, a speedrower, and/or another type of agricultural machine or vehicle. In some embodiments, the off-road machine or vehicle is a construction machine or vehicle such as a skid steer loader, an excavator, a backhoe loader, a wheel loader, a bulldozer, a telehandler, a motor grader, and/or another type of construction machine or vehicle. In some embodiments, the vehicle <NUM> includes one or more attached implements and/or trailed implements such as a front mounted mower, a rear mounted mower, a trailed mower, a tedder, a rake, a baler, a plough, a cultivator, a rotavator, a tiller, a harvester, and/or another type of attached implement or trailed implement.

According to an exemplary embodiment, the cab <NUM> is configured to provide seating for an operator (e.g., a driver, etc.) of the vehicle <NUM>. In some embodiments, the cab <NUM> is configured to provide seating for one or more passengers of the vehicle <NUM>. According to an exemplary embodiment, the operator interface <NUM> is configured to provide an operator with the ability to control one or more functions of and/or provide commands to the vehicle <NUM> and the components thereof (e.g., turn on, turn off, drive, turn, brake, engage various operating modes, raise/lower an implement, etc.). The operator interface <NUM> may include one or more displays and one or more input devices. The one or more displays may be or include a touchscreen, a LCD display, a LED display, a speedometer, gauges, warning lights, etc. The one or more input device may be or include a steering wheel, a joystick, buttons, switches, knobs, levers, an accelerator pedal, a brake pedal, etc..

According to an exemplary embodiment, the driveline <NUM> is configured to propel the vehicle <NUM>. As shown in <FIG>, the driveline <NUM> includes a primary driver, shown as prime mover <NUM>, and an energy storage device, shown as energy storage <NUM>. In some embodiments, the driveline <NUM> is a conventional driveline whereby the prime mover <NUM> is an internal combustion engine and the energy storage <NUM> is a fuel tank. The internal combustion engine may be a spark-ignition internal combustion engine or a compression-ignition internal combustion engine that may use any suitable fuel type (e.g., diesel, ethanol, gasoline, natural gas, propane, etc.). In some embodiments, the driveline <NUM> is an electric driveline whereby the prime mover <NUM> is an electric motor and the energy storage <NUM> is a battery system. In some embodiments, the driveline <NUM> is a fuel cell electric driveline whereby the prime mover <NUM> is an electric motor and the energy storage <NUM> is a fuel cell (e.g., that stores hydrogen, that produces electricity from the hydrogen, etc.). In some embodiments, the driveline <NUM> is a hybrid driveline whereby (i) the prime mover <NUM> includes an internal combustion engine and an electric motor/generator and (ii) the energy storage <NUM> includes a fuel tank and/or a battery system.

As shown in <FIG>, the driveline <NUM> includes a transmission device (e.g., a gearbox, a continuous variable transmission ("CVT"), etc.), shown as transmission <NUM>, coupled to the prime mover <NUM>; a power divider, shown as transfer case <NUM>, coupled to the transmission <NUM>; a first tractive assembly, shown as front tractive assembly <NUM>, coupled to a first output of the transfer case <NUM>, shown as front output <NUM>; and a second tractive assembly, shown as rear tractive assembly <NUM>, coupled to a second output of the transfer case <NUM>, shown as rear output <NUM>. According to an exemplary embodiment, the transmission <NUM> has a variety of configurations (e.g., gear ratios, etc.) and provides different output speeds relative to a mechanical input received thereby from the prime mover <NUM>. In some embodiments (e.g., in electric driveline configurations, in hybrid driveline configurations, etc.), the driveline <NUM> does not include the transmission <NUM>. In such embodiments, the prime mover <NUM> may be directly coupled to the transfer case <NUM>. According to an exemplary embodiment, the transfer case <NUM> is configured to facilitate driving both the front tractive assembly <NUM> and the rear tractive assembly <NUM> with the prime mover <NUM> to facilitate front and rear drive (e.g., an all-wheel-drive vehicle, a four-wheel-drive vehicle, etc.). In some embodiments, the transfer case <NUM> facilitates selectively engaging rear drive only, front drive only, and both front and rear drive simultaneously. In some embodiments, the transmission <NUM> and/or the transfer case <NUM> facilitate selectively disengaging the front tractive assembly <NUM> and the rear tractive assembly <NUM> from the prime mover <NUM> (e.g., to permit free movement of the front tractive assembly <NUM> and the rear tractive assembly <NUM> in a neutral mode of operation). In some embodiments, the driveline <NUM> does not include the transfer case <NUM>. In such embodiments, the prime mover <NUM> or the transmission <NUM> may directly drive the front tractive assembly <NUM> (i.e., a front-wheel-drive vehicle) or the rear tractive assembly <NUM> (i.e., a rear-wheel-drive vehicle).

As shown in <FIG> and <FIG>, the front tractive assembly <NUM> includes a first drive shaft, shown as front drive shaft <NUM>, coupled to the front output <NUM> of the transfer case <NUM>; a first differential, shown as front differential <NUM>, coupled to the front drive shaft <NUM>; a first axle, shown front axle <NUM>, coupled to the front differential <NUM>; and a first pair of tractive elements, shown as front tractive elements <NUM>, coupled to the front axle <NUM>. In some embodiments, the front tractive assembly <NUM> includes a plurality of front axles <NUM>. In some embodiments, the front tractive assembly <NUM> does not include the front drive shaft <NUM> or the front differential <NUM> (e.g., a rear-wheel-drive vehicle). In some embodiments, the front drive shaft <NUM> is directly coupled to the transmission <NUM> (e.g., in a front-wheel-drive vehicle, in embodiments where the driveline <NUM> does not include the transfer case <NUM>, etc.) or the prime mover <NUM> (e.g., in a front-wheel-drive vehicle, in embodiments where the driveline <NUM> does not include the transfer case <NUM> or the transmission <NUM>, etc.). The front axle <NUM> may include one or more components.

As shown in <FIG> and <FIG>, the rear tractive assembly <NUM> includes a second drive shaft, shown as rear drive shaft <NUM>, coupled to the rear output <NUM> of the transfer case <NUM>; a second differential, shown as rear differential <NUM>, coupled to the rear drive shaft <NUM>; a second axle, shown rear axle <NUM>, coupled to the rear differential <NUM>; and a second pair of tractive elements, shown as rear tractive elements <NUM>, coupled to the rear axle <NUM>. In some embodiments, the rear tractive assembly <NUM> includes a plurality of rear axles <NUM>. In some embodiments, the rear tractive assembly <NUM> does not include the rear drive shaft <NUM> or the rear differential <NUM> (e.g., a front-wheel-drive vehicle). In some embodiments, the rear drive shaft <NUM> is directly coupled to the transmission <NUM> (e.g., in a rear-wheel-drive vehicle, in embodiments where the driveline <NUM> does not include the transfer case <NUM>, etc.) or the prime mover <NUM> (e.g., in a rear-wheel-drive vehicle, in embodiments where the driveline <NUM> does not include the transfer case <NUM> or the transmission <NUM>, etc.). The rear axle <NUM> may include one or more components. According to the exemplary embodiment shown in <FIG>, the front tractive elements <NUM> and the rear tractive elements <NUM> are structured as wheels. In other embodiments, the front tractive elements <NUM> and the rear tractive elements <NUM> are otherwise structured (e.g., tracks, etc.). In some embodiments, the front tractive elements <NUM> and the rear tractive elements <NUM> are both steerable. In other embodiments, only one of the front tractive elements <NUM> or the rear tractive elements <NUM> is steerable. In still other embodiments, both the front tractive elements <NUM> and the rear tractive elements <NUM> are fixed and not steerable.

In some embodiments, the driveline <NUM> includes a plurality of prime movers <NUM>. By way of example, the driveline <NUM> may include a first prime mover <NUM> that drives the front tractive assembly <NUM> and a second prime mover <NUM> that drives the rear tractive assembly <NUM>. By way of another example, the driveline <NUM> may include a first prime mover <NUM> that drives a first one of the front tractive elements <NUM>, a second prime mover <NUM> that drives a second one of the front tractive elements <NUM>, a third prime mover <NUM> that drives a first one of the rear tractive elements <NUM>, and/or a fourth prime mover <NUM> that drives a second one of the rear tractive elements <NUM>. By way of still another example, the driveline <NUM> may include a first prime mover that drives the front tractive assembly <NUM>, a second prime mover <NUM> that drives a first one of the rear tractive elements <NUM>, and a third prime mover <NUM> that drives a second one of the rear tractive elements <NUM>. By way of yet another example, the driveline <NUM> may include a first prime mover that drives the rear tractive assembly <NUM>, a second prime mover <NUM> that drives a first one of the front tractive elements <NUM>, and a third prime mover <NUM> that drives a second one of the front tractive elements <NUM>. In such embodiments, the driveline <NUM> may not include the transmission <NUM> or the transfer case <NUM>.

As shown in <FIG>, the driveline <NUM> includes a power-take-off ("PTO"), shown as PTO <NUM>. While the PTO <NUM> is shown as being an output of the transmission <NUM>, in other embodiments the PTO <NUM> may be an output of the prime mover <NUM>, the transmission <NUM>, and/or the transfer case <NUM>. According to an exemplary embodiment, the PTO <NUM> is configured to facilitate driving an attached implement and/or a trailed implement of the vehicle <NUM>. In some embodiments, the driveline <NUM> includes a PTO clutch positioned to selectively decouple the driveline <NUM> from the attached implement and/or the trailed implement of the vehicle <NUM> (e.g., so that the attached implement and/or the trailed implement is only operated when desired, etc.).

According to an exemplary embodiment, the braking system <NUM> includes one or more brakes (e.g., disc brakes, drum brakes, in-board brakes, axle brakes, etc.) positioned to facilitate selectively braking (i) one or more components of the driveline <NUM> and/or (ii) one or more components of a trailed implement. In some embodiments, the one or more brakes include (i) one or more front brakes positioned to facilitate braking one or more components of the front tractive assembly <NUM> and (ii) one or more rear brakes positioned to facilitate braking one or more components of the rear tractive assembly <NUM>. In some embodiments, the one or more brakes include only the one or more front brakes. In some embodiments, the one or more brakes include only the one or more rear brakes. In some embodiments, the one or more front brakes include two front brakes, one positioned to facilitate braking each of the front tractive elements <NUM>. In some embodiments, the one or more front brakes include at least one front brake positioned to facilitate braking the front axle <NUM>. In some embodiments, the one or more rear brakes include two rear brakes, one positioned to facilitate braking each of the rear tractive elements <NUM>. In some embodiments, the one or more rear brakes include at least one rear brake positioned to facilitate braking the rear axle <NUM>. Accordingly, the braking system <NUM> may include one or more brakes to facilitate braking the front axle <NUM>, the front tractive elements <NUM>, the rear axle <NUM>, and/or the rear tractive elements <NUM>. In some embodiments, the one or more brakes additionally include one or more trailer brakes of a trailed implement attached to the vehicle <NUM>. The trailer brakes are positioned to facilitate selectively braking one or more axles and/or one more tractive elements (e.g., wheels, etc.) of the trailed implement.

As shown in <FIG>, the suspension system <NUM> discussed above includes a hydraulic suspension system <NUM>. In some embodiments, the hydraulic suspension system <NUM> includes a hydraulic pump (e.g., driven by the PTO <NUM> or another portion of the driveline <NUM>), a hydraulic fluid reservoir, accumulators, valves, switches, and other components. The hydraulic suspension system <NUM> can provide passive suspension or active suspension control (e.g., leveling, canting, roll control, or other active control of the orientation of the vehicle <NUM> relative to the ground). The hydraulic suspension system <NUM> includes hydraulic suspension units in the form of suspension actuators <NUM> coupled between the frame <NUM> of the vehicle <NUM> and the tractive elements <NUM>, <NUM> (e.g., the wheels) to provide spring/damping, and to raise and lower the frame <NUM> relative to the tractive elements <NUM>, <NUM>. In some embodiments, the vehicle <NUM> includes four suspension actuators <NUM>, one associated with each of the four tractive elements <NUM>, <NUM>. In some embodiments, more than four or less than four suspension actuators are included. Each suspension actuator <NUM> includes a rod end including a piston that is received in a cylinder. The hydraulic suspension system <NUM> is arranged in hydraulic communication with the suspension actuators <NUM> to adjust ride height, leveling, spring, rate, or other parameters of operation, as desired. In some embodiments, the suspension actuators <NUM> is a gas/hydraulic spring damper unit that may also be coupled to the pneumatic system <NUM> to adjust a spring or damper rate.

The pneumatic system <NUM> includes a central tire inflation system <NUM> that is coupled to tire pressure units <NUM> associated with each tractive element <NUM>, <NUM> to increase or decrease tire pressure. In some embodiments, the tire inflation system <NUM> includes an air compressor, an accumulator, and/or other components. In some embodiments, the tire pressure units <NUM> include a pneumatic valve and/or an assembly providing pressurized air to the interior of the tractive elements <NUM>, <NUM> while the vehicle <NUM> is in use.

The control system <NUM> is arranged in communication with the hydraulic suspension system <NUM> and the tire inflation system <NUM> and receives signals from a sensor array <NUM> including suspension sensors <NUM> and tire pressure sensors <NUM>. The suspension sensors <NUM> are positioned to monitor a rod side pressure and a head side pressure of the suspension actuators <NUM> and send a signal to the control system <NUM> indicative of hydraulic pressures at rod-side and head-side of the suspension actuator <NUM>. The tire pressure sensors <NUM> are positioned to monitor the tire pressure and send a signal to the control system <NUM> indicative of the tire pressure.

An adaptive tire pressure control system is provided for the vehicle <NUM> and includes the hydraulic suspension system <NUM>, the tire inflation system <NUM>, and the control system <NUM>. In some embodiments, the vehicle <NUM> is a mechanical front-wheel drive tractor. In some embodiments, the vehicle <NUM> is a four-wheel drive tractor or a vehicle <NUM> switchable between front wheel drive, rear wheel drive, and/or four wheel drive.

A front axle lead ratio Z is determined using the following equation: <MAT>.

Where Vtf is a front wheel theoretical ground speed, Vtr is a rear wheel theoretical ground speed, Zf is a front wheel transmission ratio, Zr is a rear wheel transmission ratio, Rf is a front wheel rolling radius, and Rr is a rear wheel rolling radius. The front wheel transmission ratio Zf and the rear wheel transmission ratio Zr are fixed, and variations in tire inflation pressure and wheel vertical load impact the front wheel rolling radius Rf and the rear wheel rolling radius Rr. The inflation pressure of the front wheels <NUM> and the rear wheels <NUM> can be changed via the tire inflation system <NUM> to manipulate the front axle lead ratio Z.

When the vehicle <NUM> travels without a tractive load, that is, without an implement (e.g., a trailer, a grain cart, a cultivator, etc.), an ideal situation from tractive efficiency (i.e., a ratio of drawbar power to axle power) perspective is that the front wheels <NUM> and the rear wheels <NUM> have zero slip, and therefore the slip related power loss is zero (i.e., a tractive efficiency of <NUM>).

When the front axle lead ratio Z is greater than zero percent (<NUM>%) the vehicle experiences front wheel slip and rear wheel skid and a front wheel slip force, or driving force, is opposed by a rear wheel skid force, or resistance force, so that the total longitudinal force on the vehicle <NUM> is zero. Tractive power loss occurs due to the kinematic discrepancy between the front wheels <NUM> and the rear wheels <NUM>. As the front axle lead ratio Z increases, a power loss, tire wear, and fuel consumption will increase as well.

It is desirable that the front wheels <NUM> will experience zero skid (i.e., minimized skidding) in order to maintain steering controllability. Alternatively, excessive front axle lead ratios Z will increase the front wheel slip and results in increased rear wheel digging.

When the vehicle <NUM> travels with a tractive load such as a drawbar implement, a hitched implement, a trailer, or a grain cart, and the front axle lead ratio Z is greater than zero, the front wheels <NUM> have a higher slip and the rear wheels <NUM> have a lower slip. Because the tractive efficiency of the wheels <NUM>, <NUM> is a function of slip, the front wheels <NUM> of a higher slip and the rear wheels <NUM> of a lower slip may not result in an optimal wheel tractive efficiency together, and consequently the overall vehicle tractive efficiency will not reach an optimal value.

Dynamic tractive loads cause dynamic tractor weight transfer from the front axle <NUM> to rear axle <NUM>. The greater the tractive load, the greater the weight transfer from the front axle <NUM> to the rear axle <NUM>. Typically, front tires mounted on the front wheels <NUM> and rear tires mounted on the rear wheels <NUM> are inflated based on static load on the wheel <NUM>, <NUM>. The reduced front wheel load caused by tractive loads results in an increased front wheel rolling radius Rf, and a decreased rear wheel rolling radius Rr. The dynamic weight transfer, as a result of dynamic tractive load, can further increase the kinematic discrepancy and the front axle lead ratio Z (lead-lag ratio), between front wheels <NUM> and rear wheels <NUM>, and consequently impact the tractive efficiency of the vehicle <NUM>.

This disclosure includes systems and methods for controlling tire inflation in order to adapt to tractive load variations for optimal tractive efficiency. The systems and methods inflate the tires to a baseline front tire pressure and a baseline rear tire pressure under static front axle weight and rear axle weight. During work with an implement, the systems and methods calculate tractor dynamic weight, and then adaptively adjust inflation pressures of front tires and/or rear tires to manage the front axle lead ratio Z and achieve an improved tractive efficiency.

Referring now to <FIG>, a schematic diagram of the control system <NUM> in the form of a controller <NUM> of the vehicle <NUM> of <FIG> is shown according to an example embodiment. As shown in <FIG>, the controller <NUM> includes a processing circuit <NUM> having a processor <NUM> and a memory device <NUM>; a control system <NUM> having a suspension control circuit <NUM>, a hydraulic pressure circuit <NUM>, a rolling radius circuit <NUM>, a dynamic weight circuit <NUM>, a wheel lead circuit <NUM>, and a tire pressure circuit <NUM>; and a communications interface <NUM>. Generally, the controller <NUM> is structured to determine dynamic weight distribution, determine a front axle lead ratio Z, and adjust tire inflation to provide a desired front axle lead ratio Z. The vehicle <NUM> is equipped with suspended front axle <NUM> and central tire inflation system <NUM> that can be used to determine the dynamic weight distribution or weight transfer, and to make adjustment of the tire pressures on the front tires <NUM> and the rear tires <NUM> to affect and control the front axle lead ratio Z. In some embodiments, no additional sensors are required and the dynamic weights are determined based solely on the information received from the hydraulic suspension system <NUM>. Other vehicles (e.g., tractors) may require additional sensors, such as strain gauges in order to determine dynamic weights increasing cost and complexity of the system. In some embodiments, the controller <NUM> may receive information from strain gauges and other sensors. In some embodiments, the dynamic weights are determined with a combination of strain gauge information and hydraulic suspension system <NUM> information.

In one configuration, the control system <NUM> is embodied as machine or computer-readable media that is executable by a processor, such as processor <NUM>. As described herein and amongst other uses, the machine-readable media facilitates performance of certain operations to enable reception and transmission of data. For example, the machine-readable media may provide an instruction (e.g., command, etc.) to, e.g., acquire data. In this regard, the machine-readable media may include programmable logic that defines the frequency of acquisition of the data (or, transmission of the data). The computer readable media may include code, which may be written in any programming language including, but not limited to, Java or the like and any conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program code may be executed on one processor or multiple remote processors. In the latter scenario, the remote processors may be connected to each other through any type of network (e.g., CAN bus, etc.).

In another configuration, the control system <NUM> is embodied as hardware units, such as electronic control units. As such, the control system <NUM> may be embodied as one or more circuitry components including, but not limited to, processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, etc. In some embodiments, the control system <NUM> may take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (IC), discrete circuits, system on a chip (SOCs) circuits, microcontrollers, etc.), telecommunication circuits, hybrid circuits, and any other type of "circuit. " In this regard, the control system <NUM> may include any type of component for accomplishing or facilitating achievement of the operations described herein. For example, a circuit as described herein may include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, and so on). The control system <NUM> may also include programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like. The control system <NUM> may include one or more memory devices for storing instructions that are executable by the processor(s) of the control system <NUM>. The one or more memory devices and processor(s) may have the same definition as provided below with respect to the memory device <NUM> and processor <NUM>. In some hardware unit configurations, the control system <NUM> may be geographically dispersed throughout separate locations in the vehicle <NUM>. Alternatively and as shown, the control system <NUM> may be embodied in or within a single unit/housing, which is shown as the controller <NUM>.

In the example shown, the controller <NUM> includes the processing circuit <NUM> having the processor <NUM> and the memory device <NUM>. The processing circuit <NUM> may be structured or configured to execute or implement the instructions, commands, and/or control processes described herein with respect to control system <NUM>. The depicted configuration represents the control system <NUM> as machine or computer-readable media. However, as mentioned above, this illustration is not meant to be limiting as the present disclosure contemplates other embodiments where the control system <NUM>, or at least one circuit of the control system <NUM>, is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.

The hardware and data processing components used to implement the various processes, operations, illustrative logics, logical blocks, modules and circuits described in connection with the embodiments disclosed herein (e.g., the processor <NUM>) may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, or state machine. A processor also may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some embodiments, the one or more processors may be shared by multiple circuits (e.g., the control system <NUM> may comprise or otherwise share the same processor which, in some example embodiments, may execute instructions stored, or otherwise accessed, via different areas of memory). Alternatively or additionally, the one or more processors may be structured to perform or otherwise execute certain operations independent of one or more co-processors. In other example embodiments, two or more processors may be coupled via a bus to enable independent, parallel, pipelined, or multi-threaded instruction execution. All such variations are intended to fall within the scope of the present disclosure.

The memory device <NUM> (e.g., memory, memory unit, storage device) may include one or more devices (e.g., RAM, ROM, Flash memory, hard disk storage) for storing data and/or computer code for completing or facilitating the various processes, layers and modules described in the present disclosure. The memory device <NUM> may be communicably connected to the processor <NUM> to provide computer code or instructions to the processor <NUM> for executing at least some of the processes described herein. Moreover, the memory device <NUM> may be or include tangible, non-transient volatile memory or non-volatile memory. Accordingly, the memory device <NUM> may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein.

The suspension control circuit <NUM> is structured to actively control the hydraulic suspension system <NUM> via the communications interface <NUM> to raise, lower, level, or otherwise adjust the orientation of the vehicle <NUM>. In some embodiments, the suspension control circuit <NUM> controls operation of pumps, valves, and other control components of the hydraulic suspension system <NUM> including the suspension actuator <NUM>.

The hydraulic pressure circuit <NUM> is structured to receive signals from the suspension sensors <NUM> associated with the suspension actuators <NUM>, and determine hydraulic pressures. The hydraulic pressure circuit <NUM> also determines a front axle weight and a rear axle weight based on the hydraulic pressures at rod side and head side of each suspension actuator <NUM>. In some embodiments, the hydraulic pressure circuit <NUM> records the head side hydraulic cylinder pressures and the rod side pressures of the front suspension actuators <NUM> via the suspension sensors <NUM> while vehicle <NUM> is not moving and determines a cylinder force. The hydraulic pressure circuit <NUM> then determines a static front axle weight FWS(i) and a static rear axle weight RWS(i) that is supported by the suspension actuators <NUM> based on the cylinder force while the vehicle <NUM> is stationary.

The dynamic weight circuit <NUM> is structured to determine dynamic weights during travel or field operation. A dynamic front axle weight FWD is determined by the dynamic weight circuit <NUM> based on the hydraulic pressure of each suspension actuator <NUM> recorded over time to determine a mean value of pressures. The dynamic front axle weight FWD is based on the mean value. In some embodiments, the dynamic front axle weight FWD is determined based on the mean hydraulic pressure values of the front suspension actuators <NUM> only. The determined dynamic front axle weight FWD is then used to determine a dynamic weight transfer based on a comparison of the dynamic front axle weight FWD in field operation with the static front axle weight FWS(i) determined while the vehicle <NUM> is stationary. In some embodiments, the dynamic weight circuit <NUM> determines a dynamic rear axle weight RWD is determined based on the hydraulic pressure of each suspension actuator <NUM> recorded over time to determine a mean value of pressures. The dynamic rear axle weight RWD is based on the mean value. In some embodiments, the dynamic rear axle weight RWD is determined based on the mean hydraulic pressure values of the rear suspension actuators <NUM> only. In some embodiments, the dynamic front axle weight FWD and the dynamic rear axle weight RWD are determined together based on the mean values of pressures measured at all of the suspension actuators <NUM>.

The tire pressure circuit <NUM> is structured to receive information from the tire inflation system <NUM> including the tire pressure units <NUM> and the tire pressure sensors <NUM>. The tire pressure circuit <NUM> determines current tire pressures for each of the tires <NUM>, <NUM> of the vehicle <NUM> and also stores a number of front tires <NUM> and a number of rear tires <NUM>. In some embodiments, the number of front tires <NUM> and the number of rear tires <NUM> is preprogrammed, received from a user, or automatically detected. The tire pressure circuit <NUM> is also structured to control deflation or inflation of individual tires <NUM>, <NUM> via the tire inflation system <NUM> including the tire pressure units <NUM>. The tire pressure circuit <NUM> is structured to inflate the front tires <NUM> to a baseline front tire inflation pressure Pf, and a baseline rear tire inflation pressure Pr, determine current tire pressures, and to inflate and/or deflate the front tires <NUM> and rear tires <NUM> to updated pressures during operation of the vehicle <NUM>.

The rolling radius circuit <NUM> is structured to determine a tire rolling radius for each tire <NUM>, <NUM> based on the current tire inflation pressures and tire vertical load (e.g., the static front axle weight FWS(i), the static rear axle weight RWS(i), the dynamic front axle weight FWD, and the dynamic rear axle weight RWD). In some embodiments, the relationship between the tire rolling radius and tire parameters can be captured via equations, algorithms, models, etc. In some embodiments, a test method can be used to calibrate the tire rolling radius RR(I,j) of the front tires <NUM> and the rear tires <NUM> based on the front wheel loads (e.g., FWS(i)), the rear wheel loads (e.g., RWS(i)), and tire inflation pressures. As shown in <FIG>, a rolling radius table is provided that returns a tire rolling radius when queried using the wheel weight (e.g., static or dynamic) and the inflation pressure. The rolling radius table can also be queried using the rolling radius and the wheel weight, or any other combination of inputs. In some embodiments, the wheel weight includes the static front wheel weight FWS, the dynamic front wheel weight FWD, the static rear wheel weight RWS, and/or the dynamic rear wheel weight RWD. In some embodiments, the rolling radius table receives a dynamic weight shift as an input. While the static wheel weights may be valuable for determining the baseline tire pressure, the dynamic wheel weights may be more valuable when determining the rolling radius during operation. In some embodiments, in each table, one of the rows, (e.g., front tire pressure (<NUM>)), includes the tire pressures based on a tire manufacturer's inflation table. The rolling radius circuit <NUM> returns a front tire rolling radius Rf, and a rear tire rolling radius Rr. Within this disclosure, a lookup table may refer to one or more tables that may include combined information or may include more than one table including multiple information types.

The wheel lead circuit <NUM> is structured to receive the front wheel transmission ratio Zf, the rear wheel transmission ratio Zr, the front tire inflation pressure Pf and the rear tire inflation pressure Pr from the tire pressure circuit <NUM>, the static front axle weight FWS(i) and the static rear weight RWS(i) from the hydraulic pressure circuit <NUM>, and the front tire rolling radius Rf and the rear tire rolling radius Rr from the rolling radius circuit <NUM>. The wheel lead circuit <NUM> determines a front to rear lead-lag ratio Zb, as follows: <MAT>.

Due to the dynamic weight transfer during operation of the vehicle <NUM>, the front and rear tire rolling radii change over time. The front axle lead ratio Z, is calculated iteratively and tire pressures are adjusted to maintain a desirable front axle lead ratio Z. The front axle lead ratio Z is optimized via the controller <NUM> for maximum tractive performance by adjusting the front tire pressure, the rear tire pressure, or both pressures.

The controller <NUM> carries out the tasks of data recording and weight transfer estimation, and stores at least the following information: the tractor static front weight FWS, and static rear weight RWS, the front tire rolling radius table and rear tire rolling radius table, the baseline front tire pressure Pf and rear tire pressure Pr, the number of front tires and number of rear tires, and the front weight supported by the front suspension actuators <NUM>. After the estimation of the dynamic weight transfer, the controller <NUM> determines a tire pressure adjustment (e.g., inflation or deflation) needed for optimal tractive efficiency by using the stored information. The tire inflation pressure adjustments are executed through the tire inflation system <NUM>.

As shown in <FIG>, a method <NUM> can be implemented by the systems of the vehicle <NUM> including the controller <NUM> discussed above. At step <NUM>, the controller <NUM> initiates connections to the hydraulic suspension system <NUM>, the tire inflation system <NUM>, and the sensor array <NUM>, and/or other parts of the vehicle <NUM> via the communications interface <NUM> so that the controller can determine the static front weight FWS, the static rear weight RWS, the front tire rolling radius Rf, the rear tire rolling radius Rr, the baseline front tire pressure Pf, the baseline rear tire pressure Pf, and a time period of recording for an estimation. In some embodiments, the time period of recording can be user defined or predefined within the controller <NUM> (e.g., one minute, two minutes, etc.). The time period of recording and for making adjustments to the tire pressure can also be limited or turned off after a predetermined or selected time period or a predetermined or selected number of adjustments.

At step <NUM>, the process of recording information is started. A start command can be received from a user input (e.g., via a button, a command entered through a human-machine-interface, etc.), automatically prompted by action (e.g., attachment of a drawbar implement, engagement of an accessory, etc.), or otherwise initiated. In some embodiments, a continuous execution of the method <NUM> is engaged once a start recording command is received. In some embodiments, the time period for recording includes a limited number of executions which is terminated by a stop recording command (see for example step <NUM>).

At step <NUM>, the controller <NUM> receives and records the static front weight FWS and the static rear weight RWS via the hydraulic pressure circuit <NUM>, the front tire rolling radius Rf and the rear tire rolling radius Rr by querying lookup tables via the rolling radius circuit <NUM>, and the baseline front tire pressure Pf and the baseline rear tire pressure Pf via the tire pressure circuit <NUM>.

At step <NUM>, the dynamic weight circuit <NUM> determines the dynamic front axle weight FWD and the dynamic rear axle weight RWD. In some embodiments, the dynamic weight circuit <NUM> determines dynamic weights at each tractive element <NUM>, <NUM> (e.g., wheel/tire) at each set of tractive elements <NUM>, <NUM> (e.g., a set of two wheels/tires on a left side of the vehicle <NUM> and a set of two wheels/tires or a right side of the vehicle <NUM> are determined as individual dynamic weights). Within this disclosure a dynamic weight may refer to a dynamic weight of an entire axle, an individual tractive element <NUM>, <NUM> (e.g., a wheel/tire), or a subset of tractive elements <NUM>, <NUM> (e.g., a group of wheels/tires). In some embodiments, a dynamic weight shift or a dynamic weight transfer is determined at step <NUM> by comparing the dynamic front weight FWD with the static front weight FWS determined earlier in step <NUM>.

At step <NUM>, the current front axle lead ratio Z is determined by the controller <NUM>. The tire rolling radius circuit <NUM> determines the front rolling radius Rf and the rear rolling radius Rr based on the tables discussed above. In some embodiments, the rolling radius circuit <NUM> may include a machine learning engine that receives tire pressures, dynamic weights, static weights, hydraulic pressures, and/or other inputs and determines the front rolling radius Rf and the rear rolling radius Rr using a deep neural network, a neural network, reinforcement learning, or another machine learning architecture. The front rolling radius Rf and the rear rolling radius Rr, and front and rear transmission ratios Zf and Zr (received from the drivetrain <NUM> for example) are then used by the wheel lead circuit <NUM> to determine the current front axle lead ratio Z.

At step <NUM>, the wheel lead circuit <NUM> determines a target lead ratio. In some embodiments, the target lead ratio is user defined (e.g., selected from a menu, graphical user interface, human machine interface, buttons, dials, etc.). In some embodiments, the controller <NUM> recognizes operating conditions and an operational mode automatically (e.g., towing an implement, travelling over a road, travelling in mud, etc.) and automatically selects a target lead ratio corresponding to the operating conditions. In some embodiments, the operational modes include a travel mode for travelling on a road or another level surface while the vehicle is relatively unloaded (e.g., not pulling an engaged implement such as a cultivator or a loaded wagon). In some embodiments, the target front axle lead ratio Z equals <NUM> (i.e., a <NUM>% front wheel lead) while operating in the travel mode. In some embodiments, operational modes include a field mode for operation in a field or while towing or otherwise utilizing an implement. In some embodiments, the target front axle lead ratio Z is optimized for optimal tractive efficiency (e.g., a <NUM>% front wheel lead or a target front axle lead ratio Z of <NUM>) while operating in the field mode. In some embodiments, operational modes are not used and the target front axle lead ratio Z is set based on detected activities. For example, in some embodiments, the target lead ratio desirably provides zero front wheel lead (i.e., the front axle lead ratio Z equals <NUM>) while travelling over a road or relatively level path, and/or the target lead ratio desirably provides an optimal front axle lead ratio while towing an implement or when operating in slippery conditions (e.g., mud, etc.).

At step <NUM>, the tire pressure circuit <NUM> determines a front tire pressure change and a rear tire pressure change to achieve the target lead ratio. In some embodiments, the target front tire pressure change and rear tire pressure change are achieved by reverse look up using the rolling radius tables along with the dynamic weights, and the static weights and the target lead ratio. In some embodiments, a machine learning engine can be used to correlate, learn, and determine tire pressures corresponding to the target lead ratio during operation of the vehicle <NUM>.

At step <NUM>, the controller <NUM> commands the tire inflation system <NUM> to implement the front tire pressure change and the rear tire pressure change to achieve the target lead ratio as determined by the tire pressure circuit <NUM>.

At step <NUM>, the controller <NUM> checks to determine if the tire pressure of each tire <NUM>, <NUM> is stable. If the pressures are not stable, the method <NUM> returns to step <NUM> and the tires are inflated/deflated to the desired pressures.

At step <NUM>, the controller <NUM> determines if the time period of recording has been met. If not, the method <NUM> returns to step <NUM> and the method <NUM> continues to adjust the tire inflation pressure to achieve the target lead ratio. If the time period of recording has been achieved, then the method <NUM> stops at step <NUM> and normal operation of the vehicle <NUM> continues without the method <NUM> continually running.

When the vehicle <NUM> travels without a tractive load and both the front axle <NUM> and the rear axle <NUM> of the vehicle <NUM> are engaged, that is, without an implement or a trailer or grain cart, etc., an ideal situation from tractive efficiency perspective is that both the front tractive elements <NUM> and the rear tractive elements <NUM> have zero slip, and therefore the slip related power loss is zero. In situations of front wheel lead (e.g., a positive front axle lead ratio Z), the front tractive elements <NUM> slip, and the rear tractive elements <NUM> skid. The front slip force, or driving force, is opposed by the rear skid force, or resistance force, so that the total longitudinal force on the vehicle <NUM> is zero. Tractive power loss occurs due to the kinematic discrepancy between front and rear wheels. The greater the speed lead or lag, the greater the power loss and tire wear. The fuel consumption of the vehicle <NUM> increases as the front axle lead ratio Z increases. It is desirable that front wheel will not skid in order to maintain steering controllability, and excessive front wheel lead (e.g., the front axle lead ratio Z) will increase the front wheel slip and results in rear wheel digging. When the vehicle <NUM> travels with a tractive load such as a drawbar implement, a hitched implement, a trailer, or a grain cart, in a situation of front wheel lead, the front wheels have a higher slip and the rear wheels have a lower slip. Because the tractive efficiency of a wheel is a function of its slip, the front wheels of a higher slip and the rear wheels of a lower slip may not result in an optimal wheel tractive efficiency together, and consequently the overall vehicle tractive efficiency will not reach an optimal value. Dynamic tractive load causes dynamic tractor weight transfer from front axle to rear axle. The greater the tractive load, the greater the weight transfer. In general, a tire is inflated to the pressures based on static load on the wheel. The reduced front wheel load causes the front tire rolling radius, Rf, to increase, and at the same time the heavier rear wheel load causes the rear tire rolling radius, Rr, to decrease. The dynamic weight transfer, as a result of dynamic tractive load, can further increase the kinematic discrepancy and the front axle lead ratio Z, between front and rear wheels, and consequently impact the tractive efficiency of the tractor.

Claim 1:
A system, comprising:
a hydraulic suspension system (<NUM>) including:
a front suspension actuator (<NUM>), and
a front suspension pressure sensor (<NUM>) associated with the front suspension actuator (<NUM>);
a tire inflation system (<NUM>); and
one or more processing circuits (<NUM>) comprising one or more memory devices (<NUM>) coupled to one or more processors (<NUM>), the one or more memory devices (<NUM>) configured to store instructions thereon that, when executed by the one or more processors (<NUM>), cause the one or more processors (<NUM>) to:
determine a dynamic weight based on information received from the front suspension pressure sensor (<NUM>) of the hydraulic suspension system (<NUM>),
the system being characterized in that said instructions further cause said one or more processors (<NUM>) to:
determine a current front axle lead ratio based on the dynamic weight,
determine a target front axle lead ratio, and
control operation of the tire inflation system (<NUM>) to adjust from the current front axle lead ratio to the target front axle lead ratio.