The field of the disclosure relates to self-propelled vehicles and, in particular, self-propelled vehicles that include a control system for adjusting the pitch of the vehicle during use. In some embodiments, the self-propelled vehicle may include an inclinometer for measuring the pitch of the terrain near the vehicle.
Self-propelled vehicles having a chassis with a front wheel support system and a rear wheel support system may be used in a variety of applications. As the vehicles are used, the loading on the apparatus (e.g., the carried load such as a formed bale) may cause variations in the weight carried by the front and rear support systems. The added weight may not be carried equally by the front and the rear support systems. Some support systems include a suspension system which allows relative movement between the chassis of the vehicle and the support system. Variations in the weight carried by the suspension system may change the pitch of the apparatus.
In addition, operation of the vehicle over hilly terrain will cause the weight distribution of the apparatus to shift. The shift in weight distribution causes the percentage of weight carried by the front wheel support system and by the rear wheel support system to vary. For vehicles having a suspension, this variation will cause the pitch of the chassis of the apparatus to vary relative to the terrain. In vehicles equipped with a sensor (e.g., inclinometer) for measuring the pitch of the terrain near the vehicle, changes in the relative position of the chassis to the terrain during operation of the vehicle may affect the measurements of the sensor and cause measurement error.
A need exists for systems to control the pitch of the chassis relative to a front or rear wheel support system of the vehicle in order to maintain a consistent relative pitch between the chassis and the terrain in order to allow for improved accuracy of onboard sensors such as inclinometers.
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
One aspect of the present disclosure is directed to a self-propelled vehicle. The vehicle includes a chassis and first and second rear wheels connected to the chassis. First and second front wheels are also connected to the chassis. The vehicle includes an inclinometer for sensing a ground pitch. A suspension system includes a suspension element that enables one of the first and second rear wheels and first and second front wheels to move relative to the chassis. A suspension system position sensor produces a signal based on the position of the suspension system relative to the chassis. A control unit receives signals from the suspension system position sensor. The control unit adjusts the suspension element based at least in part on the signal from the suspension system position sensor.
Another aspect of the present disclosure is directed to a self-propelled vehicle. The vehicle includes a chassis and first and second rear wheels connected to the chassis. First and second front wheels are connected to the chassis. A suspension system includes a suspension element connected to the subframe. The suspension element enables the subframe to move relative to the chassis. A suspension system position sensor produces a signal based on a distance of the suspension system from the chassis. A control unit receives signals from the suspension system position sensor. The control unit adjusts the suspension element at least in part based on the signal from the suspension system position sensor.
Yet a further aspect of the present disclosure is directed to a pitch-leveling hydraulic suspension system to enable a wheel to move relative to a chassis. The suspension system includes a hydraulic cylinder and a hydraulic pump for providing hydraulic fluid to the hydraulic cylinder. The system includes a suspension system position sensor. A control unit receives signals from the suspension system position sensor. The control unit adjusts the hydraulic cylinder at least in part based on the signal from the suspension system position sensor.
Various refinements exist of the features noted in relation to the above-mentioned aspects of the present disclosure. Further features may also be incorporated in the above-mentioned aspects of the present disclosure as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments of the present disclosure may be incorporated into any of the above-described aspects of the present disclosure, alone or in any combination.
Corresponding reference characters indicate corresponding parts throughout the drawings.
A self-propelled vehicle is generally referred to as “1” in
The vehicle may be a self-propelled agricultural vehicle such as a rake (
The self-propelled vehicle 1 is controlled from an operator station 13 (
In the illustrated embodiment, the vehicle includes a baling device 5 and a pick-up device 11 (
The vehicle 1 includes first and second rear drive wheels 17 that are driven by first and second motors 23 (
The rear wheels 17 are fixed to the chassis 9 such that the wheels 17 maintain parallel alignment with a longitudinal axis A (
The longitudinal axis A (
With reference to
The wheels 17 are powered and rotated independently by the drive systems 15. Accordingly, the wheels 17 can be rotated at different speeds by driving the motors at different speeds. In a drive wheel steering mode, the wheels 17 are driven at different speeds by the drive system 15. For example, in this mode, the motors 23 receive different amounts of fluid from the respective pumps 20 to differentiate the speed of the wheels 17. Separate fluid lines 22 extend between each pump 20 and drive motor 23 to independently rotate the wheels 17. The direction of fluid flow may be forward or reverse to independently rotate the wheels forward or reverse to propel the vehicle forward, reverse, through an arc (e.g., as during steering) or about a vertical axis midway between the drive wheels 17 (e.g., as during zero turn steering).
The vehicle 1 includes a control system to control the drive wheels 17 and front caster wheels 27 based on inputs from an operator. The control system includes a control unit 80, speed and direction control device 78, a mode selector 79 and steering mechanism which is shown as a steering wheel 67. The speed and direction control device 78, mode selector 79 and steering wheel 67 may be controlled from the operator station 13.
The mode selector 79 allows the operator to select a desired mode of operation (i.e., a drive wheel steering mode or a caster wheel steering mode). The control unit 80 receives the signal from the mode selector 79 and controls the mode of the steering system in response to the signal. The mode selector 79 may be, for example, part of a touch screen, a soft key, toggle switch, selection button or any other suitable interface for selecting the steering mode.
The speed and direction control device 78 is typically hand-operated and may be a sliding lever that causes an increase in forward speed as the lever is slid forward of a neutral position and an increase in reverse direction as the lever is slid rearward of the neutral position. The speed and direction control device 78 produces a signal in response to its position and the signal is transmitted to the control unit 80. The control unit 80 produces an output signal transmitted to the hydraulic pumps 20 that drive the rear wheels 17. The speed may also be controlled by a throttle that controls the engine speed. The vehicle 1 may be stopped by moving the speed and direction control device 78 to a zero-speed setting and/or by operating foot brake levers.
A suspension system 51 may be controlled by the control unit 80 at least in part by a signal from a suspension system position sensor 61 as further described below. The suspension system 51 may also be adjusted based on one or more other signals relayed to the control unit 80 including speed, mode and/or direction of travel. The control unit 80 regulates one or more valves 70, 71, 72 (
In the illustrated embodiment, steering may be performed by a steering mechanism shown as a steering wheel 67 which regulates the steering system. For example, in the drive wheel steering mode, a sensor 81 measures the direction and angle of the steering wheel 67 and sends signals to the control unit 80. The control unit 80 produces a signal that is transmitted to the hydraulic pumps 20 to independently regulate the rotational speeds of the first and second drive wheels 17 (i.e., the speed and direction of rotation of each drive wheel 17).
In other embodiments, speed and/or steering may be controlled by different operator controls such as wheel levers, digital inputs, joysticks, dual sticks, and headsets.
In some embodiments, the self-propelled vehicle 1 is configured to optionally operate autonomously. The vehicle 1 may include sensors (e.g., cameras, GPS sensors and the like) that sense the position of a crop (e.g., windrow) and/or that may sense the position of the vehicle. The vehicle 1 may also include a controller that sends signals to the first and second rear wheel pumps or to various actuators to independently control the first and second rear drive wheels. In some embodiments, the area in which the vehicle is propelled is mapped and the area map is used to autonomously control the operation of the vehicle in the field. In such embodiments, the vehicle may include a riding station to carry an operator or the operator station may be eliminated.
The self-propelled vehicle 1 includes first and second front caster wheels 27 that are pivotally connected to the chassis 9 about a vertical pivot axis (which may be offset from the vertical axis at a caster angle). The first and second caster wheels 27 swing below a portion of the chassis 9. The front caster wheels 27 may be spaced to allow a windrow of crop or forage material to pass between the front caster wheels 27 to, for example, engage a pick-up device 11.
Each front caster wheel 27 has a rotational axis R27 (
As shown in
The vehicle 1 includes an engine 101 (e.g., gas or diesel powered engine) that drives one or more hydraulic pumps that in turn power the various hydraulic motors and cylinders (e.g., first and second drive wheel motors and any device motors). The engine 101 also provides power for the electrical systems of the vehicle 1. As shown in
The engine 101 is disposed between the rotational axis R17 of the rear drive wheels 17 and the operator station 13 (
The front caster wheels 27 are connected to the chassis independent from each other which allows the caster wheels to be independently suspended to absorb forces transmitted during travel over uneven terrain. The front caster wheels 27 may be part of first and second swivel caster assemblies 31. Generally the first and second swivel caster assemblies 31 and subframes 41 described below are symmetric and description herein of an assembly or subframe also applies to the second assembly or subframe (e.g., description of a hub of the assembly indicates that the first assembly has a first hub and that the second assembly has a second hub). Each assembly 31 includes a hub 35 (
The hub 35 and shaft 37 form a swivel joint 43. The first and second front caster wheels 27 of the caster assemblies 31 are each connected to a subframe 41 by the swivel joint 43. The subframes 41 are suspended from the chassis 9 by a suspension system 51 having a suspension element 49, shown as a hydraulic cylinder in the illustrated embodiment. With reference to
Each subframe 41 is also pivotally attached to the chassis 9 at an outer pivot point P1 and an inner pivot point P2. In this arrangement, the chassis 9 is supported by the subframes 41 and the chassis 9 and components carried by the chassis (e.g., operator station and cab) may move up and down relative to the subframes 41 as the vehicle 1 travels over uneven terrain.
As shown in
In the illustrated embodiment, the first arm 45 is generally parallel to the longitudinal axis A (
As shown in
In other embodiments and/or in different modes of operation the front caster wheels 27 are steered. In such embodiments, the offset may be eliminated.
In a drive wheel steering mode, the vehicle 1 is steered by creating a differential speed between the first and second rear drive wheels 17 (i.e., by creating a difference between the first drive wheel rotational speed and the second drive wheel rotational speed). In this mode, each drive wheel 17 is capable of being driven forward or in reverse independent of the speed and direction of the other wheel (i.e., the drive wheels may be operated in counter-rotation). As an operator controls a steering mechanism (e.g., steering wheel), the rear drive wheels 17 rotate at different speeds to steer the vehicle 1 through an arc or deviation in the travel pathway. The speed and direction of travel (forward or rearward) may be controlled by a separate operator control. In the drive wheel steering mode, the vehicle 1 may be turned within its own footprint. In this mode, the caster wheels 27 self-align with the direction in which the drive wheels propel the vehicle, i.e., the caster wheels 27 follow the direction of travel of the rear drive wheels 17.
In a caster wheel steering mode, the swivel position of the caster wheels 27 may be controlled to steer the vehicle. As used herein, the “swivel position” of the caster wheels generally refers to the angular position of the caster wheels relative to the longitudinal axis A (
In some embodiments, the vehicle 1 includes a sensor 90 (
In some embodiments, the sensor 90 provides a signal related to the angle of inclination during or after adjustment of the steering system as described below (e.g., adjustment of one or more suspension elements) to improve the accuracy of the measurement. The signal from the sensor 90 (e.g., inclinometer) may be relayed to a controller (e.g., such as the control unit 80) to adjust the vehicle based on the signal after the suspension has been adjusted. In embodiments in which the self-propelled vehicle 1 is a self-propelled baler, the vehicle 1 may include a controller that presents a suggested bale position based on the pitch or the pitch and roll of the ground around the vehicle 1 as disclosed in commonly-owned PCT Patent Application No. PCT/US2017/033641, filed, May 19, 2017, entitled “Baling Vehicle with Automated Round Bale Ejection”, which is incorporated herein by reference for all relevant and consistent purposes.
Referring now to
In the embodiment illustrated in
The sensor 61 produces a signal based on the position of the suspension system 51 relative to the chassis 9 of the vehicle 1. The sensor 61 is communicatively connected to the control unit 80 which in turn is communicatively coupled to first valve 70, second valve 71, and third valve 72. In the illustrated embodiment, the control unit 80 is the same unit that controls operation of the drive systems. In other embodiments, the control unit 80 which adjusts the suspension system 51 is a different control unit. The control unit 80 and valves 70, 71, 72 regulate the hydraulic fluid in the hydraulic system with changes in the amount of hydraulic fluid altering the pressure supplied to suspension elements 49 (e.g., through action of accumulator 50 and pump 52). The valves 70, 71, 72 are controlled, at least in part, based on a signal produced by the control unit 80. In other embodiments, the pump 52 is controlled, at least in part, based on a signal produced by the control unit 80.
To adjust fluid pressure to suspension elements 49, a valve (e.g., the first valve 70) may be used to control the pressure in the system downstream of the valve. For example, the first valve 70 may be a proportional relieving valve that is adjusted by variable electric input (e.g., variable input from controller 80). The first valve 70 is used to regulate the amount of hydraulic fluid downstream of the first valve 70 (e.g., by adding or removing fluid downstream of the valve) to control the pressure in suspension elements 49 and accumulator 50. The illustrated arrangement of valves (e.g., first valve 70, second valve 71, and third valve 72) is an example and any valve or combination of valves which allows the suspension elements 49 to be controlled to adjust the pitch of the chassis 9 of the vehicle 1 may be used unless stated otherwise. In other embodiments, the pitch of the vehicle chassis 9 is controlled by devices other than valves (e.g., by controlling the hydraulic output of a dedicated hydraulic pump).
Another embodiment of a hydraulic suspension system 51 is shown in
The suspension system 51 may also be configured to absorb shock during operation of the vehicle 1. The absorber 50 allows fluid to flow to and from the suspension elements 49 when the vehicle travels over uneven terrain. The suspension system 51 may include a check valve 82 and/or restrictor 84 disposed between the second valve 71 and the third valve 72. The check valve 82 is configured to allow hydraulic fluid to flow to the accumulator 50 (e.g., to flow relatively quickly to the accumulator 50 for shock absorption when vehicle 1 encounters a change in terrain). The restrictor 84 is configured to allow hydraulic fluid to flow back to the suspension elements 49 (e.g., to dampen the flow of fluid to the suspension elements 49 to smooth the ride of an operator).
By varying the pressure of the hydraulic fluid supplied to the suspension elements 49, the position of the suspension elements 49 may be adjusted to allow the pitch of the chassis 9 of the vehicle 1 to maintain a desired distance relative to the subframe 41. Any control system in which the suspension system 51 (e.g., suspension elements 49) is adjusted based at least in part on a signal from the suspension system position sensor 61 may generally be used unless stated otherwise.
In the illustrated embodiment, the vehicle 1 includes a single suspension system position sensor 61. In other embodiments, the vehicle 1 includes a first suspension system position sensor 61 that measures the position of the suspension relative to the chassis on the first side 58 (
The control unit 80 that controls the position of the suspension elements 49 based at least in part on a signal from the suspension system position sensor 61 includes a processor and a memory. The processor processes the signals received from various sensors, selectors and control devices of the system. The memory stores instructions that are executed by the processor.
Control unit 80 may be a computer system. Computer systems, as described herein, refer to any known computing device and computer system. As described herein, all such computer systems include a processor and a memory. However, any processor in a computer system referred to herein may also refer to one or more processors wherein the processor may be in one computing device or a plurality of computing devices acting in parallel. Additionally, any memory in a computer device referred to herein may also refer to one or more memories wherein the memories may be in one computing device or a plurality of computing devices acting in parallel.
The term processor, as used herein, refers to central processing units, microprocessors, microcontrollers, reduced instruction set circuits (RISC), application specific integrated circuits (ASIC), logic circuits, and any other circuit or processor capable of executing the functions described herein. The above are examples only, and are thus not intended to limit in any way the definition and/or meaning of the term “processor.”
In one embodiment, a computer program is provided to enable control unit 80, and this program is embodied on a computer readable medium. In an example embodiment, the computer system is executed on a single computer system, without requiring a connection to a server computer. In a further embodiment, the computer system is run in a Windows® environment (Windows is a registered trademark of Microsoft Corporation, Redmond, Wash.). In yet another embodiment, the computer system is run on a mainframe environment and a UNIX® server environment (UNIX is a registered trademark of X/Open Company Limited located in Reading, Berkshire, United Kingdom). Alternatively, the computer system is run in any suitable operating system environment. The computer program is flexible and designed to run in various different environments without compromising any major functionality. In some embodiments, the computer system includes multiple components distributed among a plurality of computing devices. One or more components may be in the form of computer-executable instructions embodied in a computer-readable medium.
The computer systems and processes are not limited to the specific embodiments described herein. In addition, components of each computer system and each process can be practiced independent and separate from other components and processes described herein. Each component and process also can be used in combination with other assembly packages and processes.
In some embodiments, pitch adjustment of the vehicle 1 may be suspended during one or more operations of the vehicle 1. For example, pitch-adjustment (and, as in some embodiments, suspension system shock absorption) may be suspended during (1) counter-steering of the vehicle (i.e., when the rear wheels 17 rotate in opposite directions), (2) during zero-turn steering (i.e., when one rear wheel 17 is stationary while the other rear wheel 17 rotates), (3) during operation at vehicle speeds less than a threshold (e.g., less than 3 mph), (4) while the vehicle travels in reverse (i.e., both drive wheels rotate in reverse), and/or (5) during ejection of a load from the vehicle (e.g., in embodiments in which the self-propelled vehicle is a baler, during ejection of a bale). Pitch-leveling may be suspended by closing the third valve 72 to isolate the suspension elements 49 from the accumulator 50. The third valve 72 may be a proportional relieving valve. In other embodiments, two or more valves block flow to the accumulator 50 and/or block flow between suspension elements 49. In some embodiments, control unit 80 receives signals from the speed and direction control device 78 (
The control unit 80 may be configured such that the suspension elements 49 are adjusted to a targeted compression length (or within a range of compression lengths). The targeted compression length may be a compression length which allows for a full range of suspension, such as near the center of the range of motion of the suspension element 49. By moving the suspension elements (e.g., hydraulic cylinders) to a compressed length at which a substantially full range of suspension may be achieved, the suspension elements are less limited in the amount of suspension they provide even with changing vehicle loads and/or travel over terrain in which the pitch of the ground changes. In some embodiments, the suspension elements are not centered within their effective range of motion.
In some embodiments, the control unit 80 and/or sensor 61 are calibrated to match the pitch of the chassis 9 with the ground pitch. Calibration may be performed when the ground pitch is substantially zero. Calibration may also be performed under load (e.g., with a bale in the baling chamber to account for pitch change caused by tire squat or deflection).
Leveling of the pitch of a vehicle having a front-wheel suspension is shown schematically in
Similarly, traveling over ground that is downward pitched (
In the illustrated embodiment, the front wheels 27 are suspended by suspension elements 49 (
Compared to conventional vehicles, embodiments of the self-propelled vehicle of the present disclosure have several advantages. By adjusting the suspension elements at least in part based on the signal from the suspension system position sensor, the pitch of the chassis of the vehicle may be made generally level with the pitch of the ground as the load of the vehicle changes and/or the pitch of the ground changes during travel of the vehicle. Adjusting the suspension elements allows the suspension elements to be adjusted toward a target compression length such a compression length with a larger increase in the suspension range (e.g., toward the center of the range of motion of the suspension elements). By maintaining the pitch of the vehicle chassis closer to the pitch of the ground during operation of the vehicle, the caster wheels are more maneuverable during vehicle turning and the vehicle operator does not sense misalignment of the pitch of the vehicle chassis with the pitch of the ground (i.e., sense a “nose-up” or “nose-down” condition). Further, in vehicles that include an inclinometer onboard the vehicle to measure the pitch of the ground, the accuracy of the inclinometer may be improved by leveling the vehicle chassis pitch with the pitch of the ground.
As used herein, the terms “about,” “substantially,” “essentially” and “approximately” when used in conjunction with ranges of dimensions, concentrations, temperatures or other physical or chemical properties or characteristics is meant to cover variations that may exist in the upper and/or lower limits of the ranges of the properties or characteristics, including, for example, variations resulting from rounding, measurement methodology or other statistical variation.
When introducing elements of the present disclosure or the embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” “containing” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. The use of terms indicating a particular orientation (e.g., “top”, “bottom”, “side”, etc.) is for convenience of description and does not require any particular orientation of the item described.
As various changes could be made in the above constructions and methods without departing from the scope of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawing[s] shall be interpreted as illustrative and not in a limiting sense.
This application is a continuation of U.S. patent application Ser. No. 16/057,341, filed Aug. 7, 2018, which claims the benefit of U.S. Provisional Patent Application No. 62/544,139, filed Aug. 11, 2017 and U.S. Provisional Patent Application No. 62/586,453, filed Nov. 15, 2017, each of which being incorporated herein by reference in its entirety.
Number | Date | Country | |
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62544139 | Aug 2017 | US | |
62586453 | Nov 2017 | US |
Number | Date | Country | |
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Parent | 16057341 | Aug 2018 | US |
Child | 16876667 | US |