ACTIVE RIDE CONTROL ON CONSTRUCTION VEHICLES

BACKGROUND

The present disclosure relates generally to a work vehicle (e.g., a tractor, a truck, etc.). More specifically, the present disclosure relates to a vehicle with a hydraulic system. The hydraulic system facilitates the operation of hydraulic subsystems and reduces oscillations within the vehicle during loading events.

A common problem of work vehicles is the lack of axle suspension. For this reason alternative strategies have been explored to reduce the oscillations transmitted to the cabin during loading events of the work vehicle.

One such strategy is a passive ride control suspension (“PRC”). A PRC typically uses a hydraulic accumulator and dissipating valves connected to the lift cylinders of a boom of the work vehicle. The hydraulic flow oscillates between actuators and accumulator in such a PRC. The hydraulic capacitance embodied in a hydraulic accumulator slows the system dynamics and the valves dissipate the vibrational energy. However, this solution results in the addition of hydraulic circuitry to the original system, which means increasing costs, and limited range of working effectiveness.

The use of an accumulator also introduces the requirement to service or replace the accumulator within the lifetime of the vehicle. Over time, the gas precharge that acts as the cushioning device will degrade due to permeation through the accumulator structure. This results in decreased performance and operator discomfort. In typical work vehicle installations, the accumulator may not be easily accessible for service-leading to further operator annoyance.

Different Active Ride Control (“ARC”) strategies have also been studied in the past. Since many work vehicles utilize an open hydraulic circuit, the analyzed solutions typically use electro-actuated directional valves between actuators and supply. During ride conditions, the directional valves are continuously controlled, switching connection between actuators and pump or tank line to mitigate the oscillations transmitted to the operator.

SUMMARY

For this reason, an ARC solution is needed to control work vehicle oscillations through a pump displacement control methodology.

One embodiment relates to a work vehicle including: one or more user input devices; a work implement; a hydraulic system including; a pump configured to cause a differential in hydraulic pressure between a pump inlet and a pump outlet; a flow director in hydraulic communication with the pump outlet and configured to adjust a flow of hydraulic fluid between one or more hydraulic components; a hydraulic actuator including a first chamber and a second chamber and configured to adjust a position of the work implement; and an angle sensor configured to receive a signal associated with an angle of the work implement; a load sensor configured to; receive an indication of the pressure exerted on the hydraulic actuator; and transmit the indication of the pressure exerted on the hydraulic actuator to the pump to adjust a hydraulic displacement of the pump; and a control system including processing circuitry and configured to: receive, by the processor from the one or more user input devices, a desired angle of the work implement; receive, by the processor from the one or more user input devices, a command to reduce oscillations of the work vehicle; and transmit a signal, by the processor, to the flow director to adjust a flow of hydraulic fluid from the pump outlet to both the first chamber and the second chamber of the hydraulic actuator.

In another embodiment, the flow director is an independent metering valve configured to independently control the flow of hydraulic fluid from the pump outlet to both the first chamber and the second chamber of the hydraulic actuator.

In another embodiment, the hydraulic actuator is a hydraulic piston and cylinder, wherein the cylinder rotatably coupled to the work vehicle and the hydraulic piston is rotatably coupled to the work vehicle.

In another embodiment, the hydraulic system does not include an accumulator or a dissipating valve.

In another embodiment, the work implement is a boom.

In another embodiment, load sensor is a load sensing hydraulic circuit.

In another embodiment, the load sensor is an electronic circuit including a pressure sensor configured to receive a signal associated with the pressure at the hydraulic actuator.

According to another implementation of the present disclosure, a method for reducing oscillations in a work vehicle is presented, the steps including: receiving, by a load sensor circuit, an indication of the pressure exerted on a hydraulic actuator; transmitting, by the load sensor hydraulic circuit, the indication of the pressure exerted on the hydraulic actuator to the pump to adjust a hydraulic displacement of the pump; receiving, by a processor, from one or more user input devices, a desired angle of a work implement coupled to the hydraulic actuator; receiving, by the processor from the one or more user input devices, a command to reduce oscillations of the work vehicle; and transmitting a signal, by the processor, to the flow director to adjust a flow of hydraulic fluid from the pump outlet to both the first chamber and the second chamber of the hydraulic actuator.

In another embodiment, the hydraulic actuator is a hydraulic piston and cylinder, the cylinder rotatably coupled to the work vehicle and the hydraulic piston is rotatably coupled to the work vehicle.

In another embodiment, the command to reduce oscillations of the work vehicle is associated with an engageable driving mode.

In another embodiment, In another embodiment, the load sensor is a load sensing hydraulic circuit.

In another embodiment, the load sensor is an electronic circuit including a pressure sensor configured to receive a signal associated with the pressure at the hydraulic actuator.

According to another implementation of the present disclosure, a hydraulic system is presented, including; a pump configured to cause a differential in hydraulic pressure between a pump inlet and a pump outlet; a flow director in hydraulic communication with the pump outlet and configured to adjust a flow of hydraulic fluid between one or more hydraulic components; a hydraulic actuator including a first chamber and a second chamber and configured to adjust a position of the work implement; and an angle sensor configured to receive a signal associated with an angle of the work implement; a load sensor configured to; receive an indication of the pressure exerted on the hydraulic actuator; and transmit the indication of the pressure exerted on the hydraulic actuator to the pump to adjust a hydraulic displacement of the pump; and a control system including processing circuitry and configured to: receive, by the processor from the one or more user input devices, a desired angle of the work implement; receive, by the processor from the one or more user input devices, a command to reduce oscillations of the work vehicle; and transmit a signal, by the processor, to the flow director to adjust a flow of hydraulic fluid from the pump outlet to both the first chamber and the second chamber of the hydraulic actuator.

In another embodiment, the hydraulic actuator is a hydraulic piston and cylinder, the cylinder rotatably coupled to the work vehicle and the hydraulic piston is rotatably coupled to the work vehicle.

In another embodiment, the hydraulic system does not include an accumulator or a dissipating valve.

In another embodiment, the command to reduce oscillations of the work vehicle is associated with an engageable driving mode.

In another embodiment, the load sensor is a load sensing hydraulic circuit.

In another embodiment, the load sensor is an electronic circuit including a pressure sensor configured to receive a signal associated with the pressure at the hydraulic actuator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vehicle, according to an exemplary embodiment.

FIG. 2 is a schematic block diagram of the vehicle of FIG. 1, according to an exemplary embodiment.

FIG. 3 is a schematic block diagram of a driveline of the vehicle of FIG. 1, according to an exemplary embodiment.

FIG. 4 is a schematic block diagram of a hydraulic system of the vehicle of FIG. 1, according to an exemplary embodiment.

FIG. 5 is a schematic block diagram of a hydraulic system of the vehicle of FIG. 1, according to an exemplary embodiment.

FIG. 6 is a schematic block diagram of a hydraulic system of the vehicle of FIG. 1, according to an exemplary embodiment.

FIG. 7 is a schematic block diagram of a hydraulic system of the vehicle of FIG. 1, according to an exemplary embodiment.

FIG. 8 is a schematic block diagram of a hydraulic system of the vehicle of FIG. 1, according to an exemplary embodiment.

FIG. 9 is a schematic block diagram of a hydraulic system of the vehicle of FIG. 1, according to an exemplary embodiment.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate certain exemplary embodiments in detail, it should be understood that the present disclosure 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.

Overall Vehicle

According to the exemplary embodiment shown in FIGS. 1-3, a machine or vehicle, shown as vehicle 10, includes a chassis, shown as frame 12; a body assembly, shown as body 20, coupled to the frame 12 and having an occupant portion or section, shown as cab 30; operator input and output devices, shown as operator interface 40, that are disposed within the cab 30; a drivetrain, shown as driveline 50, coupled to the frame 12 and at least partially disposed under the body 20; a vehicle braking system, shown as braking system 100, coupled to one or more components of the driveline 50 to facilitate selectively braking the one or more components of the driveline 50; and a vehicle control system, shown as control system 200, coupled to the operator interface 40, the driveline 50, and the braking system 100. In other embodiments, the vehicle 10 includes more or fewer components.

The chassis of the vehicle 10 may include a structural frame (e.g., the frame 12) formed from one or more frame members coupled to one another (e.g., as a weldment). Additionally or alternatively, the chassis may include a portion of the driveline 50. By way of example, a component of the driveline 50 (e.g., the transmission 52) may include a housing of sufficient thickness to provide the component with strength to support other components of the vehicle 10.

According to an exemplary embodiment, the vehicle 10 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 10 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 30 is configured to provide seating for an operator (e.g., a driver, etc.) of the vehicle 10. In some embodiments, the cab 30 is configured to provide seating for one or more passengers of the vehicle 10. According to an exemplary embodiment, the operator interface 40 is configured to provide an operator with the ability to control one or more functions of and/or provide commands to the vehicle 10 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 40 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 50 is configured to propel the vehicle 10. As shown in FIG. 3, the driveline 50 includes a primary driver, shown as prime mover 52, and an energy storage device, shown as energy storage 54. In some embodiments, the driveline 50 is a conventional driveline whereby the prime mover 52 is an internal combustion engine and the energy storage 54 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 50 is an electric driveline whereby the prime mover 52 is an electric motor and the energy storage 54 is a battery system. In some embodiments, the driveline 50 is a fuel cell electric driveline whereby the prime mover 52 is an electric motor and the energy storage 54 is a fuel cell (e.g., that stores hydrogen, that produces electricity from the hydrogen, etc.). In some embodiments, the driveline 50 is a hybrid driveline whereby (i) the prime mover 52 includes an internal combustion engine and an electric motor/generator and (ii) the energy storage 54 includes a fuel tank and/or a battery system.

As shown in FIG. 3, the driveline 50 includes a transmission device (e.g., a gearbox, a continuous variable transmission (“CVT”), etc.), shown as transmission 56, coupled to the prime mover 52; a power divider, shown as transfer case 58, coupled to the transmission 56; a first tractive assembly, shown as front tractive assembly 70, coupled to a first output of the transfer case 58, shown as front output 60; and a second tractive assembly, shown as rear tractive assembly 80, coupled to a second output of the transfer case 58, shown as rear output 62. According to an exemplary embodiment, the transmission 56 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 52. In some embodiments (e.g., in electric driveline configurations, in hybrid driveline configurations, etc.), the driveline 50 does not include the transmission 56. In such embodiments, the prime mover 52 may be directly coupled to the transfer case 58. According to an exemplary embodiment, the transfer case 58 is configured to facilitate driving both the front tractive assembly 70 and the rear tractive assembly 80 with the prime mover 52 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 58 facilitates selectively engaging rear drive only, front drive only, and both front and rear drive simultaneously. In some embodiments, the transmission 56 and/or the transfer case 58 facilitate selectively disengaging the front tractive assembly 70 and the rear tractive assembly 80 from the prime mover 52 (e.g., to permit free movement of the front tractive assembly 70 and the rear tractive assembly 80 in a neutral mode of operation). In some embodiments, the driveline 50 does not include the transfer case 58. In such embodiments, the prime mover 52 or the transmission 56 may directly drive the front tractive assembly 70 (i.e., a front-wheel-drive vehicle) or the rear tractive assembly 80 (i.e., a rear-wheel-drive vehicle).

As shown in FIGS. 1 and 3, the front tractive assembly 70 includes a first drive shaft, shown as front drive shaft 72, coupled to the front output 60 of the transfer case 58; a first differential, shown as front differential 74, coupled to the front drive shaft 72; a first axle, shown front axle 76, coupled to the front differential 74; and a first pair of tractive elements, shown as front tractive elements 78, coupled to the front axle 76. In some embodiments, the front tractive assembly 70 includes a plurality of front axles 76. In some embodiments, the front tractive assembly 70 does not include the front drive shaft 72 or the front differential 74 (e.g., a rear-wheel-drive vehicle). In some embodiments, the front drive shaft 72 is directly coupled to the transmission 56 (e.g., in a front-wheel-drive vehicle, in embodiments where the driveline 50 does not include the transfer case 58, etc.) or the prime mover 52 (e.g., in a front-wheel-drive vehicle, in embodiments where the driveline 50 does not include the transfer case 58 or the transmission 56, etc.). The front axle 76 may include one or more components.

As shown in FIGS. 1 and 3, the rear tractive assembly 80 includes a second drive shaft, shown as rear drive shaft 82, coupled to the rear output 62 of the transfer case 58; a second differential, shown as rear differential 84, coupled to the rear drive shaft 82; a second axle, shown rear axle 86, coupled to the rear differential 84; and a second pair of tractive elements, shown as rear tractive elements 88, coupled to the rear axle 86. In some embodiments, the rear tractive assembly 80 includes a plurality of rear axles 86. In some embodiments, the rear tractive assembly 80 does not include the rear drive shaft 82 or the rear differential 84 (e.g., a front-wheel-drive vehicle). In some embodiments, the rear drive shaft 82 is directly coupled to the transmission 56 (e.g., in a rear-wheel-drive vehicle, in embodiments where the driveline 50 does not include the transfer case 58, etc.) or the prime mover 52 (e.g., in a rear-wheel-drive vehicle, in embodiments where the driveline 50 does not include the transfer case 58 or the transmission 56, etc.). The rear axle 86 may include one or more components. According to the exemplary embodiment shown in FIG. 1, the front tractive elements 78 and the rear tractive elements 88 are structured as wheels. In other embodiments, the front tractive elements 78 and the rear tractive elements 88 are otherwise structured (e.g., tracks, etc.). In some embodiments, the front tractive elements 78 and the rear tractive elements 88 are both steerable. In other embodiments, only one of the front tractive elements 78 or the rear tractive elements 88 is steerable. In still other embodiments, both the front tractive elements 78 and the rear tractive elements 88 are fixed and not steerable.

In some embodiments, the driveline 50 includes a plurality of prime movers 52. By way of example, the driveline 50 may include a first prime mover 52 that drives the front tractive assembly 70 and a second prime mover 52 that drives the rear tractive assembly 80. By way of another example, the driveline 50 may include a first prime mover 52 that drives a first one of the front tractive elements 78, a second prime mover 52 that drives a second one of the front tractive elements 78, a third prime mover 52 that drives a first one of the rear tractive elements 88, and/or a fourth prime mover 52 that drives a second one of the rear tractive elements 88. By way of still another example, the driveline 50 may include a first prime mover that drives the front tractive assembly 70, a second prime mover 52 that drives a first one of the rear tractive elements 88, and a third prime mover 52 that drives a second one of the rear tractive elements 88. By way of yet another example, the driveline 50 may include a first prime mover that drives the rear tractive assembly 80, a second prime mover 52 that drives a first one of the front tractive elements 78, and a third prime mover 52 that drives a second one of the front tractive elements 78. In such embodiments, the driveline 50 may not include the transmission 56 or the transfer case 58.

As shown in FIG. 3, the driveline 50 includes a power-take-off (“PTO”), shown as PTO 90. While the PTO 90 is shown as being an output of the transmission 56, in other embodiments the PTO 90 may be an output of the prime mover 52, the transmission 56, and/or the transfer case 58. According to an exemplary embodiment, the PTO 90 is configured to facilitate driving an attached implement and/or a trailed implement of the vehicle 10. In some embodiments, the driveline 50 includes a PTO clutch positioned to selectively decouple the driveline 50 from the attached implement and/or the trailed implement of the vehicle 10 (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 100 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 50 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 70 and (ii) one or more rear brakes positioned to facilitate braking one or more components of the rear tractive assembly 80. 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 78. In some embodiments, the one or more front brakes include at least one front brake positioned to facilitate braking the front axle 76. In some embodiments, the one or more rear brakes include two rear brakes, one positioned to facilitate braking each of the rear tractive elements 88. In some embodiments, the one or more rear brakes include at least one rear brake positioned to facilitate braking the rear axle 86. Accordingly, the braking system 100 may include one or more brakes to facilitate braking the front axle 76, the front tractive elements 78, the rear axle 86, and/or the rear tractive elements 88. In some embodiments, the one or more brakes additionally include one or more trailer brakes of a trailed implement attached to the vehicle 10. 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.

Active Ride Control

The active ride control (“ARC”) of the present disclosure is used to minimize cabin oscillations of the vehicle 10 devoid of axles suspensions through the use of a hydraulic system incorporated into the vehicle 10. Specifically, the disclosed ARC strategy is based on pressure control of a variable displacement pump to reduce pressure oscillations in one or more boom lift cylinders of vehicle 10. As a consequence of a reduction in pressure variations in the boom lift actuators, the cabin 30 oscillations decrease.

Other active ride control strategies previously proposed use hydraulic control valves in the working lines of the one or more boom actuators of vehicle 10. However, the pump control of the present disclosure is based on a pressure control that can be achieved with new and unique circuit alternatives, which connect one or more of the actuator ports to the pump outlet. In some embodiments, the pump control is based on a control of the outlet pressure used to mitigate the pressure oscillations in the boom actuators, thus reducing implement and cabin vibrations. The feedback of the controller can be either hydraulic pressure feedback, electro-hydraulic pressure feedback, or acceleration feedback. Two exemplary embodiments are described herein: (1) with an independent metering valve (“IMV”) and (2) with additional directional valves and an electro-hydraulic pump with pressure control.

Using an independent metering valve on a construction vehicle (e.g., vehicle 10 of FIG. 1) can also increase fuel economy when activating the working functions. Varying the user command, a standard directional valve will proportionally change an opening area of the standard directional valve and induce a differential pressure between flow source and actuator. To obtain the same outcome, the spools of an IMV can be maintained fully opened and the pump can produce a lower displacement. During lowering operations, while a traditional directional valve requires supply flow, and therefore power, the proposed embodiments allow the boom to descend with no energy expense. Indeed, the load can be lowered connecting both actuators chambers to tank and using gravitational energy. To control the boom speed, it may be sufficient to meter out the flow from the load holding side depending on user demand. In some embodiments, the boom is rotatably coupled to the vehicle 10 (e.g., through axles or pins). This allows the boom to rotate with respect to the vehicle 10. One or more hydraulic actuators (e.g., pistons and cylinders) are rotatably coupled on one end (e.g., the cylinder) to the vehicle 10, and rotatably coupled to the boom on the other end (e.g., the piston). In this manner, as the piston is actuated through hydraulic flow, the boom lifts and lowers (with respect to the vehicle 10) accordingly.

Turning now to FIG. 4, an exemplary hydraulic system 400 of vehicle 10 is shown using a PRC system. In this embodiment, no IMV or additional directional valves are shown.

The hydraulic system 400 may illustrate a working section 406 of a proportional directional valve mounted on the vehicle 10 of FIG. 1. Hydraulic system 400 may include a valve 404. The hydraulic system 400 may be used in concert with an accumulator (not shown) and check valves (or dissipating valves) connected to one or more boom actuators in a PRC embodiment. In some embodiments, the valve 404 is a seven-port, four-way valve with a first position 405, a second position 408, a third position 410, and a fourth position 412. The hydraulic system 400 may also include a check valve 402,414, both coupled (in fluid communication). The check valves 402, 414 allowing a release of pressure into the system in the event that the boom experiences an increased load (e.g., hitting a pothole). The hydraulic system 400 may also include various relief valves 416, 418, and 420, as well as check valve 422 and valve 424. The working section shown in hydraulic system 400 may be coupled to a hydraulic load sensing system 430 to regulate the pressure and flow of hydraulic fluid through the hydraulic system 400 based on the demand of the load being operated by the boom actuators. The function of the load sensing circuit is described in greater detail at FIG. 5.

The third position 410 of the valve 404 corresponds to the closed position in which all seven ports are closed. The second position 408 and the third position 412 correspond to a raising and lower position, respectively. In one embodiment, port 440 is in fluid communication with a recirculation valve 426, port 442 is coupled to a pump 428 configured to cause a pressure differential between an inlet of the pump (e.g., a pump inlet 525 of FIG. 5) and an outlet of the pump (e.g., a pump outlet 526 of FIG. 5), port 444 is coupled to the tank 432, and port 446 is coupled to the tank 432. The first position 405 corresponds to a float position that connects both boom actuator chambers to the tank 432.

A PRC system such as hydraulic system 400 may use a hydraulic accumulator and check valves 402, 414 connected to the boom actuators to regulate shock to the system and thereby reduce oscillations transmitted from the boom to the cabin 30 of the vehicle 10.

Turning now to FIG. 5, an exemplary hydraulic system 500 of vehicle 10 is shown utilizing an ARC system, including a work section 506 (shown in greater detail in FIG. 7), a load sensing circuit 510 (e.g., hydraulic circuitry and/or electronic circuitry), a variable displacement pump 502, a tank 504, pilot tubes 512, 514, 516, hydraulic cylinders 508, a solenoid 522, and a boom angle sensor 518.

In the embodiment illustrated in FIG. 5, the hydraulic system 500 includes a work section 506 (e.g., hydraulic circuity) configured to fluidly connect a pump outlet 526 of the pump 502 to both working ports of the hydraulic actuators 508 (e.g., through the use of one or more directional valves, as shown in FIG. 7). The hydraulic actuators 508 may couple a working implement 509 (e.g., a boom) to the vehicle 10. The hydraulic system 500 may also include a load sensing circuit 510 to adjust the pump 502 displacement to generate a pressure substantially equal to the load on the hydraulic actuators 508. The load sensing circuit 510 may be coupled to a hydraulic line 528 (e.g., pipe, hose, etc.) connecting the work section 506 to the hydraulic actuators 508 by a pilot hose 512 to pass an indication of the hydraulic pressure at hydraulic actuators 508. In some embodiments, hydraulic line 528 is one or more lines. In some embodiments, the pilot hose 512 is coupled to a compensator valve within the load sensing circuit 510, which may transmit the resultant pressure by means of a hydraulic fluid to actuate a swash plate coupled to the pump 502. By adjusting the swash plate, the displacement of the pump 502 is adjusted (e.g., as the pressure at pilot hose 512 increases, the swash plate increases the displacement of the pump 502). Solenoid 522 may be a spring-loaded swash plate to regulate the pump displacement of pump 502. In other embodiments, the solenoid 522 is a solenoid electronically controlled by the load sensing circuitry 510 (e.g., by control signals sent by the load sensing circuit 510). In some embodiments, the load sensing circuit 510 is purely hydraulic, purely electronic, purely mechanical, or a hybrid of hydraulic, electronic, and/or mechanical components. In some embodiments, the pressure of the fluid supplying the hydraulic actuators 508 (as transmitted by pilot hose 512), a boom angle, and a desired boom angle 520 are the feedback signals manipulated by the load sensing circuit 510 (which may include processing circuitry of an electronic controller). The resulting output signal is used to command the pump displacement of the pump 502 by actuating the solenoid 522 (or swash plate) through a line 516. The line 516 may be a hydraulic line or an electronic communications line, depending on the embodiment of the load sensing circuit 510 and the solenoid 522.

The boom angle (e.g., signal ϑ), coming from a sensor 518 (e.g., a potentiometer, rotary encoder, limit switch, magnetic linear position sensor, etc.) configured to measure an angle of the working implement (e.g., a boom) coupled to the hydraulic actuators 508 is compared to the desired angle 520 (e.g., reference value ϑ_ref). The desired angle 520 is received by an operator input device (e.g., operator interface 40). Depending on error amplitude and current pressure on the piston side of the lifting actuators p_A, the load sensing pressure (e.g., the pressure at the hydraulic line 528) is controlled to reach the pressure able to balance the load supported by the hydraulic actuators 508 at the pump outlet 526. Upon the working pressure in hydraulic line 528 being sufficiently large enough to support the load required at hydraulic actuators 508, the connection between the pump 502 and both the chambers of the hydraulic actuators 508 is opened through the directional valve (as shown in FIG. 7) in the work section 506 and the ARC mode is engaged. When the ARC is active, the load sensing circuit 510 will constantly be active to slightly change the pump displacement at the pump outlet 526 and optimize the control action. These continual adjustments allow the vehicle 10 to travel/operate with a loaded front work implement and maintain ride control, thus reducing oscillations transmitted to the cabin 30 during loading events (e.g., hitting a pothole, riding over uneven terrain, etc.)

In this embodiment, the hydraulic circuitry (with a pump displacement and pressure control) emulates the dampening action of a PRC solution without the addition of accumulator and dissipating valves or the need for hydraulic control valves in the working lines (e.g., hydraulic line 528) of the hydraulic actuators—thus reducing costs/complexity of manufacture and future maintenance.

This pump control principle is based on a pressure control that can be achieved with different circuit alternatives, which connects one or more of the actuator ports of hydraulic actuators 508 to the pump outlet 526. In some embodiments, the pump control is based on a control of the outlet pressure used to mitigate the pressure oscillations in the boom actuators, thus reducing implement and cabin vibrations. The feedback of the controller (or load sensing circuit 510) can be either hydraulic pressure feedback, or electro-hydraulic pressure feedback, or acceleration feedback.

In an alternative embodiment, the load holding side of the hydraulic actuators 508 may be fluidly coupled to the supply (e.g., pump 502) and the lower pressure side to the tank 504. In this embodiment, the minimum pressure setting of the pump should be lower than the pressure needed to balance the load on the load holding side to avoid the hydraulic actuators 508 rising. This embodiment can be implemented using an IMV (as shown if FIG. 7) with electronic load sensing control on a variable displacement pump with pressure control or with a standard proportional directional valve and an electro-hydraulic pump with pressure control.

In some embodiments, the active ride control implementation may be adjusted on and off by an operator of vehicle 10. For example, the vehicle 10 may have an active ride control mode that may be toggled on/off through the use of operator interface 40 of FIG. 1. In some embodiments, the active ride control mode is automatically engaged upon reaching a predetermined threshold speed of the vehicle 10 and/or a threshold load on the hydraulic actuators 508. Toggling the ARC mode on may involve adjusting the placement of one or more valve spools within the hydraulic system 500, 600, 700, 800, 900.

Once the ARC mode is activated, the pressure signal transmitted over line 516 given to the pump 502 results in a certain pressure at the pump outlet 526 due to changes in the pump 502 (e.g., changes in position of the swash plate, etc.) to sustain the existing load at the hydraulic actuators 508. Depending on the boom position desired by the user (as determined by an input to the operator interface 40) and the external load on the hydraulic actuators (as generated by the load on a connected work implement, e.g., a front bucket), the pressure is adjusted accordingly. In some embodiments, to avoid undesired boom motion, only when the desired pressure is reached do the directional valve spools open, and thereby connecting the supply line from the pump 502 to both actuators chambers of the hydraulic actuators 508. When the ARC mode is functioning, there will be close to no motion of the boom. With the objective of keeping the hydraulic actuator 508 pressure as constant as possible, the pump displacement will slightly vary depending on the effect of road disturbance on the hydraulic actuators 508. Hydraulic fluid may flow between actuator chambers and the boom will fluctuate consequently. The vibrations caused by an uneven road condition will be damped and result in limited oscillations transmitted to the cabin 30, thus decreasing the vertical acceleration experienced by the operator of vehicle 10.

In some embodiments, the ARC mode uses a directional valve (electronically actuated to allow the fluid flow control to be active while the vehicle 10 is operational/driving. The directional valve may either connect the two actuator chambers (e.g., of hydraulic actuators 508) to the supply line (e.g., hydraulic line 528) or connect the load holding side of the cylinder to the supply line (e.g., hydraulic line 528) and the lower pressure side to the tank 504, in one of the alternative embodiments.

Turning now to FIG. 6, an exemplary hydraulic system 600 of vehicle 10 is shown, with a displacement control 610. The hydraulic system 600 may be substantially similar to the hydraulic system 500 of FIG. 5. However, the hydraulic system 600 may provide the displacement control 610 in place of the load sensing circuit 510 of FIG. 5. The displacement control 610 may receive an input signal from line 612 (e.g., hydraulic line, communication line, etc.) and an input signal from line 614 (e.g., a hydraulic line, communication line, etc.). The input signal from line 612 is the working pressure of one or more hydraulic actuators 608 as exerted in hydraulic line 628. The hydraulic actuators 608 may couple a working implement 609 (e.g., a boom) to the vehicle 10. The working pressure is produced primarily at pump 602 and then passed through a work section 606 (the work section 606 is shown in greater detail in FIG. 7). As in the embodiment illustrated in FIG. 5, the working pressure in hydraulic line 628 may be read by any number of sensors (e.g., pressure gauge, a pressure transducer, pilot tube, etc.). In one embodiment, line 612 is a pilot line which transmits an indication of the working pressure through a small diameter hydraulic line. In other embodiments, the working pressure is read by a sensor and transmitted as an electronic signal (e.g., a control signal, binary signal, etc.) through line 612. In such embodiments, line 612 is a communication line.

The displacement control 610 may also receive an indication of a boom angle 618 of a boom (or alternative work implement) coupled to the hydraulic actuators 508 and a desired boom angle 620 as received by the operator interface 40. In some embodiments, the line 614 is a communication line configured for transmitting electronic signals and/or communication signals and/or control signals. According to an embodiment, a boom angle error is transmitted over line 614. In other embodiments, both the boom angle 618 and the desired angle 620 are transmitted to the displacement control 614 over line 614 and the boom angle error (e.g., the difference between the boom angle 618 and the desired angle 620) is calculated at the displacement control 610.

FIG. 6 illustrates a schematic of the ARC implementation with pump displacement controlled by an electro-hydraulic pump (e.g., the pump 602). Depending on the boom angle ϑ error with respect to the desired boom angle 620 and pressure on a piston side of the hydraulic actuators 508 (e.g., p_A), a displacement control signal is sent from the displacement control 610 to the electro-hydraulic pump 602. Once the pressure at the pump outlet 626 is able to balance a load exerted on the hydraulic actuators (e.g., by the bucket lifting a payload), the spools of a directional valve in the work section 606 are adjusted to connect a supply line 629 to both actuators chambers of the hydraulic actuators 608. During riding conditions of the vehicle 10, the connection in the work section 606 is maintained open (either partially or completely) and the displacement control 610 will constantly be active to slightly change the pump displacement and optimize the control action.

Turning now to FIG. 7, an exemplary working section 706 (including an IMV) of a hydraulic system 700 of vehicle 10 is shown. The work section 706 may include an electronic controller 712 (e.g., processing circuitry, ROM, EEPROM, memory, etc.) to receive user input 707 (e.g., from the operator interface 40) and feedback signals 710 (e.g., from directional valve 720, directional valve 728, a working pressure of hydraulic lines 740, 741, desired and actual boom angles, etc.) and outputs control signals to directional valves 720, 728 to actuate the directional valves to change a position of a spool in the directional valves 720, 728.

Directional valve 720 may be a three port, three position valve with a first position 722, a second position 724, and a third position 726. Each position 722, 724, 726 may include three ports, including a pump port 752 (in fluid communication with a pump 702), a tank port 754 (in fluid communication with a tank 704), and a working line port 750 (in fluid communication with a first chamber 708 of a hydraulic actuator).

Directional valve 728 may be a three port, three position valve with a first position 730, a second position 732, and a third position 734. Each position 730, 732, 734 may include three ports, including a pump port 752, 762 (in fluid communication with a pump 702), a tank port 754, 764 (in fluid communication with a tank 704), and a working line port 750, 760 (in fluid communication with a second chamber 709 of a hydraulic actuator).

As described in FIGS. 5-6, when the supply pressure as output by the pump 702 reaches the desired value sufficient to maintain the load exerted on the hydraulic actuator, the electronic controller sends a control signal to the solenoids of the directional valves 720, 728 to adjust the position of the internal spools to connect supply line and actuators chambers (e.g., move from the second positions 724, 732 to the first positions 722, 730. This results in the pump 702 being connected to both chambers 708, 709 of the hydraulic actuator. The chambers 708, 709 may rotatably couple a working implement 711 (e.g., a boom) to the vehicle 10. During riding conditions, the directional valves 720, 728 will remain completely or partially open to maintain as little pressure drop as possible.

Turning now to FIG. 8, an exemplary hydraulic system 800 of vehicle 10 is shown with a directional valve 802 placed in parallel with a standard directional circuit 826.

FIG. 8 shows one alternative embodiment able to fulfill the proposed ARC with the addition of the directional valve 802, and with an electro-hydraulic pump 828 with displacement control. When the pressure on the supply line 830 is enough to sustain a load exerted on the actuator chambers 822, 824, the standard directional circuit 826 remains in center position 820, the additional directional valve 802 switches to connect actuator chambers 822, 824 to the electro-hydraulic pump 828. The directional valve 802 is controlled by one or more pilot lines 832, 834, which move the spool of the directional valve 802. The directional valve 802 may be a three-port, two-position valve with a first position 804 with pump port 808, a first chamber port 810, and a second chamber port 812. The second position 806 may include a pump port 814, a first chamber port 816, and a second chamber port 818. The first position 804 is a closed position and the second position 806 is an open position with both chambers 822, 824 in fluid communication with the pump 830. The chambers 822, 824 may rotatably couple a working implement 811 (e.g., a boom) to the vehicle 10.

FIG. 8 illustrates an implementation of the ARC without the use of an “IMV” (e.g., working section 706 of FIG. 7). Indeed, with the implementation of an electro-hydraulic variable displacement pump with pressure control, the directional valve block can have different architectures. The additional directional valve 802 that allows connection between pump 830 and actuators chambers 822, 824 could be placed in parallel to the original standard directional valve 826 (as described above). The typical loading cycle would not be affected by this modification. The directional valve 802 would be normally closed and, when requested by the user (e.g., when engaging an ARC mode), the spool could switch to the second position 806 for increased comfort during riding conditions due to the dampening effect. In alternative, an additional directional valve could be placed in series to the original standard directional valve 830 (shown in FIG. 9).

Turning now to FIG. 9, an exemplary hydraulic system 900 of vehicle 10 is shown with an additional directional valve 902. In this embodiment, the additional directional valve 902 is in series with the standard directional circuit 905 (as described in FIG. 4) and is able to direct the hydraulic flow from actuator chambers 940, 942 to a tank 932, during standard operations, and a pump 920 to the actuator chambers 940, 942 when an ARC mode is engaged. When the directional valve 930 is in the center position 931, the additional directional valve 902 would switch from a first position 906 (coupled the tank 932) to a second position 904 (coupled to the pump 920).

In the embodiment illustrated in FIG. 9, the pump 920 may be an electro-hydraulic pump with displacement control. When the pressure on the supply line 921 is enough to sustain the load exerted on the actuator chambers 940, 942, the standard valve 930 moves from center position 931 to a float position 933, and the additional directional valve 902 switches to the second position 904. The chambers 940, 942 may rotatably couple a working implement 911 (e.g., a boom) to the vehicle 10. In the transition the additional directional valve 902 has priority. In this way, even if the directional valve 930 is still in a second position 935, both chambers 940, 942 are already connected to the supply line 921, avoiding undesired boom motion. During riding conditions, the standard valve 930 will remain in the float position 933 and the directional valve 902 in the open configuration.

In this embodiment, the directional valve 902 is able to direct the hydraulic flow from the actuator chambers 940, 942 to the tank 932, during standard operations, and to the supply line 920 (which is coupled to the pump 920) in the ARC mode.

As utilized herein with respect to numerical ranges, the terms “approximately,” “about,” “substantially,” and similar terms generally mean +/−10% of the disclosed values, unless specified otherwise. As utilized herein with respect to structural features (e.g., to describe shape, size, orientation, direction, relative position, etc.), the terms “approximately,” “about,” “substantially,” and similar terms are meant to cover minor variations in structure that may result from, for example, the manufacturing or assembly process and are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the disclosure as recited in the appended claims.

A system of one or more computers can be configured to perform particular operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that in operation causes or cause the system to perform the actions. One or more computer programs can be configured to perform particular operations or actions by virtue of including instructions that, when executed by data processing apparatus, cause the apparatus to perform the actions.

It should be noted that the term “exemplary” and variations thereof, as used herein to describe various embodiments, are intended to indicate that such embodiments are possible examples, representations, or illustrations of possible embodiments (and such terms are not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

The term “coupled” and variations thereof, as used herein, means the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent or fixed) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members coupled directly to each other, with the two members coupled to each other using a separate intervening member and any additional intermediate members coupled with one another, or with the two members coupled to each other using an intervening member that is integrally formed as a single unitary body with one of the two members. If “coupled” or variations thereof are modified by an additional term (e.g., directly coupled), the generic definition of “coupled” provided above is modified by the plain language meaning of the additional term (e.g., “directly coupled” means the joining of two members without any separate intervening member), resulting in a narrower definition than the generic definition of “coupled” provided above. Such coupling may be mechanical, electrical, or fluidic.

References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below”) are merely used to describe the orientation of various elements in the figures. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.

The present disclosure contemplates methods, systems, and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure may be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

Although the figures and description may illustrate a specific order of method steps, the order of such steps may differ from what is depicted and described, unless specified differently above. Also, two or more steps may be performed concurrently or with partial concurrence, unless specified differently above. Such variation may depend, for example, on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations of the described methods could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps.

The term “client or “server” include all kinds of apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, a system on a chip, or multiple ones, or combinations, of the foregoing. The apparatus may include special purpose logic circuitry, e.g., a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). The apparatus may also include, in addition to hardware, code that creates an execution environment for the computer program in question (e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross-platform runtime environment, a virtual machine, or a combination of one or more of them). The apparatus and execution environment may realize various different computing model infrastructures, such as web services, distributed computing and grid computing infrastructures.

The systems and methods of the present disclosure may be completed by any computer program. A computer program (also known as a program, software, software application, script, or code) may be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code). A computer program may be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

The processes and logic flows described in this specification may be performed by one or more programmable processors executing one or more computer programs to perform actions by operating on input data and generating output. The processes and logic flows may also be performed by, and apparatus may also be implemented as, special purpose logic circuitry (e.g., an FPGA or an ASIC).

Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random access memory or both. The essential elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data (e.g., magnetic, magneto-optical disks, or optical disks). However, a computer need not have such devices. Moreover, a computer may be embedded in another device (e.g., a vehicle, a Global Positioning System (GPS) receiver, etc.). Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example semiconductor memory devices (e.g., EPROM, EEPROM, and flash memory devices; magnetic disks, e.g., internal hard disks or removable disks; magneto-optical disks; and CD ROM and DVD-ROM disks). The processor and the memory may be supplemented by, or incorporated in, special purpose logic circuitry.

To provide for interaction with a user, implementations of the subject matter described in this specification may be implemented on a computer having a display device (e.g., a CRT (cathode ray tube), LCD (liquid crystal display), OLED (organic light emitting diode), TFT (thin-film transistor), or other flexible configuration, or any other monitor for displaying information to the user. Other kinds of devices may be used to provide for interaction with a user as well; for example, feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback).

Implementations of the subject matter described in this disclosure may be implemented in a computing system that includes a back-end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a client computer) having a graphical user interface or a web browser through which a user may interact with an implementation of the subject matter described in this disclosure, or any combination of one or more such back end, middleware, or front end components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a LAN and a WAN, an inter-network (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks).

It is important to note that the construction and arrangement of the vehicle 10 and the systems and components thereof (e.g., the driveline 50, the braking system 100, the control system 200, etc.) as shown in the various exemplary embodiments is illustrative only. Additionally, any element disclosed in one embodiment may be incorporated or utilized with any other embodiment disclosed herein.

ACTIVE RIDE CONTROL ON CONSTRUCTION VEHICLES

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

International Classifications

Abstract

Description

Claims