The present disclosure is directed to a steering system for an articulated vehicle and, more particularly, to a steering system utilizing select control of individual wheel speed and/or direction of rotation.
Machines and vehicles with multiple segments may be steered by articulation between the segments. Actuation of the articulation is performed by one or more hydraulic cylinders bridging between the articulated vehicle segments. In some cases, the vehicle may include an electrically powered drive system. For example, the vehicle may be powered by one or more electric power sources (e.g., batteries) instead of an internal combustion engine. For a vehicle at a work site, such as a mine, there are certain driving modes that use only minimal steering input. Nevertheless, since the articulated steering is hydraulically operated, the entire hydraulic system must be kept pressurized, powered up, and running even to make the most minute steering inputs.
The present disclosure is directed to drive systems that address one or more of the issues discussed above.
The present disclosure is directed to a steering system for an articulated vehicle that is auxiliary to the hydraulic steering system. In particular, the steering system may utilize selective control of individual wheel speed and/or direction of wheel rotation to articulate the vehicle independent of the hydraulic steering system. For example, in some embodiments, the hydraulic steering valve may be opened so that fluid may flow in and out of the hydraulic steering cylinders freely, thus rendering the hydraulic steering cylinders passively movable. In some cases, the hydraulic system may even be turned off to conserve energy. This conservation of energy may be particularly beneficial for a vehicle that utilizes an electric power source.
In one aspect, the present disclosure is directed to an articulated vehicle. The vehicle may include a front chassis segment including a pair of front wheels including a first front wheel on a first side of the vehicle and a second front wheel on a second, opposite side of the vehicle; a rear chassis segment including a pair of rear wheels, including a first rear wheel on the first side of the vehicle and a second rear wheel on the second side of the vehicle; and an articulating joint between the front chassis segment and the rear chassis segment. In addition, the vehicle may include at least one actuation device configured to control the articulation of the articulating joint. Further, the vehicle may include a front drive system configured to drive the first front wheel and the second front wheel; and a rear drive system configured to drive the first rear wheel and the second rear wheel. Also, the vehicle may include a braking system including brakes that are individually actuatable for each wheel of the vehicle. In addition, the vehicle may include a controller including a device processor and a non-transitory computer readable medium including instructions stored thereon and executable by the device processor for controlling articulation of the vehicle by performing the following steps: utilizing the front drive system to apply drive power to the pair of front wheels; actuating brakes associated with the second front wheel to counteract the application of drive power to the second front wheel; utilizing the rear drive system to apply drive power to the pair of rear wheels; and actuating brakes associated with the first rear wheel to counteract the application of drive power to the first rear wheel.
In another aspect, the present disclosure is directed to an articulated vehicle. The vehicle may include a front chassis segment including a pair of front wheels including a first front wheel on a first side of the vehicle and a second front wheel on a second, opposite side of the vehicle; a rear chassis segment including a pair of rear wheels, including a first rear wheel on the first side of the vehicle and a second rear wheel on the second side of the vehicle; and an articulating joint between the front chassis segment and the rear chassis segment. The vehicle may also include at least one actuation device configured to control the articulation of the articulating joint. In addition, the vehicle may include a first electric motor configured to drive the first front wheel; a second electric motor configured to drive the second front wheel; a third electric motor configured to drive the first rear wheel; and a fourth electric motor configured to drive the second rear wheel. Also, the vehicle may include a controller including a device processor and a non-transitory computer readable medium including instructions stored thereon and executable by the device processor for controlling articulation of the vehicle by performing the following steps: applying a first level of drive power to the first front wheel; and applying a second level of drive power to the second front wheel to drive the second front wheel at a slower speed than the first front wheel.
In another aspect, the present disclosure is directed to n articulated vehicle. The vehicle may include a front chassis segment including a pair of front wheels including a first front wheel on a first side of the vehicle and a second front wheel on a second, opposite side of the vehicle; a rear chassis segment including a pair of rear wheels, including a first rear wheel on the first side of the vehicle and a second rear wheel on the second side of the vehicle; and an articulating joint between the front chassis segment and the rear chassis segment. In addition, the vehicle may include at least one actuation device configured to control the articulation of the articulating joint. Further, the vehicle may include a first electric motor configured to drive the first front wheel; a second electric motor configured to drive the second front wheel; a third electric motor configured to drive the first rear wheel; and a fourth electric motor configured to drive the second rear wheel. Also, the vehicle may include a controller including a device processor and a non-transitory computer readable medium including instructions stored thereon and executable by the device processor for correcting a cornering line of the vehicle by performing the following steps: driving the pair of front wheels in a first direction; and driving the pair of rear wheels in a second direction opposite the first direction in order to move the vehicle laterally.
Other systems, methods, features and advantages of the embodiments will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the embodiments, and be protected by the following claims.
The embodiments can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, with emphasis instead being placed upon illustrating the principles of the embodiments. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.
The disclosed embodiments are directed to articulated vehicles. For purposes of this disclosure, the term “articulated vehicle” will be understood to refer to a vehicle with a front segment and a rear segment attached to the front segment in an articulatable manner and in which the vehicle is steered by controlling the articulation of the vehicle.
In some embodiments, the disclosed concepts may be implemented in a vehicle configured for use in mining operations. For example, the accompanying figures illustrate vehicles configured for use in underground mining operations. It will be understood, however, that the disclosed drive system concepts may be implemented in any of various types of vehicles, including, for example, road-going vehicles, off-road vehicles, work machines, mining vehicles, space vehicles, and any other type of vehicle.
In some embodiments, the disclosed concepts may be implemented in an electric vehicle. The vehicle includes at least two electric motors. For example, one motor may be operatively connected to each axle. In some embodiments, an electric motor may be operatively connected to each individual wheel. In some embodiments, the vehicle may be driven solely by electric power. In other embodiments, the vehicle may be a hybrid vehicle, operating on a combination of electric power and an internal combustion engine. For example, in some cases, one axle may be driven by power from a combustion engine, and a second axle may be driven by electrical power.
As used herein, the term “fixedly attached” shall refer to two components joined in a manner such that the components may not be readily separated (for example, without destroying one or both components). The term “removably attached” shall refer to components that are attached to one another in a readily separable manner (for example, with fasteners, such as bolts, screws, etc.).
As used herein, the terms “up,” “upper,” “top,” “height,” etc., and “down,” “lower,” “bottom,” etc. shall refer to components and locations along a substantially vertical direction. Such terms shall be used with respect to the disclosed vehicles with the wheels on the ground (or floor) as intended during use.
In some embodiments, the brakes may be actuated selectively on individual wheels in order to articulate the vehicle to thereby steer the vehicle.
As shown in
In some embodiments, vehicle 100 may be an electrically powered vehicle. Accordingly, as shown in
In some embodiments, the vehicle may be provided with a primary steering system and an auxiliary steering system. For example, in some embodiments, the vehicle may include a primary steering system that includes hydraulic cylinders and/or another type of actuator, such as an electric motor. The hydraulic cylinders and/or electric motors may be provided on either or both sides of the articulating joint between chassis segments, and may lengthen or shorten in order to articulate the vehicle. The auxiliary steering system may be an electronically controlled braking system that selectively controls braking at individual wheels in order to individually regulate wheel speed at each corner of the vehicle. The vehicle may be configured to render the hydraulic cylinders or electric motors of the primary steering system inactive and passive, allowing the chassis forces caused by selective braking of individual wheels to articulate the vehicle.
In some embodiments, during certain activities, the primary steering system may be turned off while the auxiliary system is in use. For example, mining vehicles often drive over significant distances without requiring much steering input. This type of driving is referred to as “tramming.” When tramming, the vehicle may turn off the primary steering system (e.g., by turning off the hydraulic system or merely depressurizing it, for example, by turning off the hydraulic pump) and utilize selective braking on individual wheels to steer the vehicle. In some embodiments, a tramming mode with this functionality may be selectable by the vehicle operator. In some embodiments, the vehicle may automatically enter tramming mode after a period of time in which the vehicle has been operated without much steering input.
Aspects of the present disclosure are described in association with figures illustrating flowcharts and/or block diagrams of methods, apparatus (systems), and computing products. It will be understood that each block of the flowcharts and/or block diagrams can be implemented by computer readable instructions. The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of various disclosed embodiments. Accordingly, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions. In some implementations, the functions set forth in the figures and claims may occur in an alternative order than listed and/or illustrated.
In some embodiments, the vehicle may include dual drive systems. For example, as shown in
The vehicle may also include a differential on each axle. In some embodiments, as shown in
Front locking differential 250 may be locked and unlocked hydraulically. In order to lock and unlock front locking differential 250, a differential valve 255 may be controlled by a controller 260. The hydraulic system associated with front locking differential 250 may also include a pilot pressure accumulator 265 and a hydraulic pump 270 that produces hydraulic pilot pressure. Controller 260 may control differential valve 255 in order to regulate the amount of hydraulic pressure that is delivered to front locking differential 250 to thereby lock and unlock the differential.
As shown in
The vehicle may also include a braking system including brakes that are individually actuatable for each wheel of the vehicle. For example, as shown in
Controller 260 may include various computing and communications hardware, such as servers, integrated circuits, displays, etc. Further, controller 260 may include a device processor and a non-transitory computer readable medium, such as a memory, including instructions executable by a device processor to perform the processes discussed herein. For example, the computer readable medium may include instructions stored thereon and executable by the device processor for controlling articulation of the vehicle.
The non-transitory computer readable medium may include any suitable computer readable medium, such as a memory, e.g., RAM, ROM, flash memory, or any other type of memory known in the art. In some embodiments, the non-transitory computer readable medium may include, for example, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of such devices. More specific examples of the non-transitory computer readable medium may include a portable computer diskette, a floppy disk, a hard disk, a read-only memory (ROM), a random access memory (RAM), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), an erasable programmable read-only memory (EPROM or Flash memory), a digital versatile disk (DVD), a memory stick, and any suitable combination of these exemplary media. A non-transitory computer readable medium, as used herein, is not to be construed as being transitory signals, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. Controller 260 may include networking hardware configured to interface with other nodes of a network, such as a LAN, WLAN, or other networks. In some cases, communications between components may be made via the Internet, a cellular network, WIFI, or other suitable communications network.
Any suitable communication platforms and/or protocols may be utilized for communication between controller 260 and other components of the system. Since the various sources of information may each have their own platform and/or protocol, the system may be configured to interface with each platform and/or protocol to receive the data.
In some embodiments, the computer readable medium may include instructions for articulating the vehicle using the braking system. For example, the computer readable medium may include instructions for utilizing the front drive system to apply drive power to the pair of front wheels and actuating brakes associated with the second front wheel to counteract the application of drive power to the second front wheel. In addition, the computer readable medium may include instructions for utilizing the rear drive system to apply drive power to the pair of rear wheels, and actuating brakes associated with the first rear wheel to counteract the application of drive power to the first rear wheel. By actuating the brakes at opposing corners of the vehicle, a torque may be created about articulating joint 300. The torque may be permitted to articulate the vehicle. Thus, selective braking of individual wheels may be utilized to steer the vehicle.
In order to permit articulation by the auxiliary steering system, the primary steering system may be rendered passive. For example, in a vehicle with a hydraulic primary steering system, such as vehicle 100, the valve or valves associated with first hydraulic steering cylinder 225 and second hydraulic steering cylinder 230 may be opened to permit fluid to easily flow in and out of the cylinders. This permits articulation of the vehicle from secondary forces, such as selective braking of individual wheels. It will be understood that the valves associated with the hydraulic steering cylinders may be integrated with the cylinders themselves or provided as separate components of the hydraulic system. Further, it will also be understood that, in some embodiments, the hydraulic steering system may include two or more steering valves.
In addition, in some embodiments, the non-transitory computer readable medium of the controller may further include instructions for turning off a hydraulic system associated with the hydraulic steering cylinders prior to controlling articulation of the vehicle via selective braking of the individual wheels of the vehicle. For example, during tramming, the hydraulic pump or the entire hydraulic system may be turned off, thus conserving energy.
As shown in
In some embodiments, vehicle 600 may be an electrically powered vehicle. Accordingly, as shown in
In some embodiments, the vehicle may include a multi-drive propulsion system. For example, as shown in
As shown in
In some embodiments, the computer readable medium of controller 790 may include instructions for performing the following steps: applying a first level of drive power to the first front wheel, and applying a second level of drive power to the second front wheel to drive the second front wheel at a slower speed than the first front wheel. That is, a different amount of torque may be applied to each front wheel in order to drive the wheels at different speeds.
By driving the wheels at different speeds about the vehicle, a torque may be created about articulating joint 800. The torque may be permitted to articulate the vehicle. As shown in
In order to facilitate this articulation via different wheel speeds, the hydraulic steering valve associated with the hydraulic steering cylinders may be opened to render the hydraulic steering system passive.
It will be noted that, in some embodiments, the non-transitory computer readable medium may further include instructions for selectively actuating brakes associated with the one or more of the wheels to counteract the application of drive power to the respective wheel in order to contribute to the articulation of the articulating joint. That is, the differentiation of wheel speed may be further augmented by the select application of braking power to individual wheels.
In some embodiments, the selectively controlling wheel speed at individual wheels may be utilized to correct the cornering line taken by a vehicle when navigating a curve. In some cases, vehicles are tasked with operating in tight areas. For example, in underground mining environments, there may be very little space for the vehicles to operate. In some mines, turns in the mining shaft may present limited space for mining vehicles to get through. The vehicles may be required to take a very precise cornering “line” in order to successfully navigate the corner.
In some embodiments, the disclosed vehicles may be configured to adjust a cornering line mid-corner. For example, with the vehicle articulated, the vehicle may drive the front wheels forward and the rear wheels rearward. The result will be that the tires scrub and the vehicle moves laterally. Similarly, the front wheels may be driven rearward and the rear wheels may be driven forward to move the vehicle laterally in the other direction.
As shown in
In addition, it will also be understood that the front of the vehicle may be moved more or less laterally than the rear of the vehicle by driving the front wheels at different speeds than the rear wheels. In addition, further sophistication of the line correction may be provided by driving the front wheels at different speeds than one another and/or by driving the rear wheels at different speeds than one another. It will also be understood that the different wheel speeds may be provided at individual wheels by driving individual wheel motors and/or by select braking as described above.
It will be understood that the auxiliary steering methods discussed herein may be used while the vehicle is traveling forward and/or in reverse.
While various embodiments have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible that are within the scope of the embodiments. Although many possible combinations of features are shown in the accompanying figures and discussed in this detailed description, many other combinations of the disclosed features are possible. Any feature of any embodiment may be used in combination with or substituted for any other feature or element in any other embodiment unless specifically restricted. Therefore, it will be understood that any of the features shown and/or discussed in the present disclosure may be implemented together in any suitable combination. Accordingly, the embodiments are not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.