Patent Application
20120153671
The present disclosure relates generally to traction slip, and, more particularly, to a traction slip indicator.
Agricultural, industrial, mining, and earth-moving machines often operate in worksites with poor traction caused by, for example, relatively poor terrain and/or relatively poor operating conditions. In many instances, poor traction causes the driven wheels of a machine to slip relative to the ground. Efficient operation of the machine often requires an operator to apply maximum power to drive the machine during hauling or loading operations, while avoiding wheel slip. Wheel slip is typically a result of an operator applying too much power or speed to the wheels relative to the traction conditions of the worksite. Wheel slip is an inefficient operation of the machine that can waste power and damage components of the machine, such as the tires of the driven wheels, unnecessarily adding cost to the operation of the machine. For example, the cost of replacing a tire, both in actual replacement cost and machine down time, can be quite substantial.
Maximizing power and speed, while avoiding wheel slip can be difficult and is often achieved based on operator experience and skill. Additionally, an operator may not have a direct line of sight to the wheels and thus may not be able to see the wheels slipping. For example tractors and other earth moving machines often have large fenders to protect an operator and other components of the machine from debris. In addition, an operator's line of sight is usually directed to a work tool on the machine during a loading and/or hauling operation.
One method for indicating wheel slip to an operator is disclosed in UK Patent Application GB 2 101 324 to Steel (“the '324 application”). The '324 application discloses a wheel slip indicator that provides a visual indication of the relative traction of one ground engaging member relative to the remaining ground engaging members. The wheel slip indicator compares the relative speed of the ground engaging members via a plurality of speed transducers so that traction of any one ground engaging member can be compared with the traction of the other ground engaging members. The wheel slip indicator also includes a display that shows the relative magnitude of the speed of each of the ground engaging members, as well as the percentage differential of wheel slip between the left-side and right-side ground engaging members via respectively illuminated indicator columns. If there is a loss of traction of any of the ground engaging members, the relative magnitude of the speed of the slipping ground engaging member will be different relative to the non-slipping ground engaging members.
Although the method of the '324 application may visually show which one of a plurality of ground engaging members is slipping, it may not do so within an operator's peripheral line of sight. As such, an operator may need to look away from an operating task, e.g., operating a work tool or driving the machine, to see the display of the wheel slip indicator of the '324 application. Additionally, the wheel slip indicator of the '324 application may not display a repeating pattern that is indicative of the amount or direction of wheel slip of a given ground engaging member.
The present disclosure is directed to overcoming one or more of the shortcomings set forth above.
In one aspect, the present disclosure is directed to a method for indicating traction slip. The method includes sensing traction slip of at least one driven traction device of a machine and selectively activating at least one indicator in a repeating pattern. The repeating pattern is indicative of the sensed traction slip of the at least one driven traction device. The at least one indicator is a visual indicator, an audible indicator, or a vibratory indicator.
In another aspect, the present disclosure is directed to a machine. The machine includes a first traction device engaging a surface that is configured to selectively propel the machine relative to the surface. The machine also includes an operator cab including a frame that at least partially surrounds the operator cab. The frame defines at least one operator sight path through the frame and at least partially defines a periphery of the at least one operator sight path. The machine also includes a first set of indicator lights disposed on the frame at the periphery of the at least one operator sight path. The machine further includes a controller configured to determine slip between the first traction device and the surface. The controller selectively illuminates the first set of indicator lights in a repeating pattern indicative of the determined slip between the first traction device and the surface.
Wheels 14 may be configured to engage a surface of the worksite in which machine 12 operates. Although generally described as including wheels, it is contemplated that machine 12 may include tracks or any other ground engaging traction device known in the art. Machine 12 may also be configured to selectively supply power to drive one or more of wheels 14 to propel and drive machine 12 around the worksite. It is contemplated that machine 12 may include any number of wheels 14 and may be configured to selectively supply power to any number of wheels 14. As such, one or more of wheels 14 may be driven wheels and one or more of wheels 14 may non-driven wheels.
Machine 12 may further include one or more sensors respectively configured to establish a signal as a function of a sensed physical parameter. For example, a gear shift sensor 34 may be configured to sense a position of one or more operator control devices 22, a traction speed sensor 36 may be configured to sense the speed of wheels 14 with respect to machine 12, and a surface speed sensor 38 may be configured to sense the speed of machine 12 with respect to a surface of the worksite. It is contemplated that gear shift sensor 34 may include a plurality of sensors, such as, for example sensors 34a, 34b respectively configured to sense a position of one of operator control devices 22, e.g., a pedal (not referenced) and a gear shifter (not referenced). It is contemplated that sensors 34, 36, 38 may embody any conventional type of sensor known in the art. The function of sensors 34, 36, 38 is further described below in conjunction with the description of controller 32 with reference to
As shown in
Cab 18 may further include a frame 26 surrounding an operator and generally defining the contours of cab 18. Frame 26 may include one or more windows defining one or more operator sight paths from inside cab 18 to the remainder of machine 12 and to the worksite. The one or more windows may be separated by one or more frame members and may be closed windows, i.e., windows having glass or other transparent material enclosing the interior of cab 18, or may be open windows, i.e., windows without glass or other transparent material. As such, an operator may have one or more sight paths through the windows and frame 26 to see implement 16 so that the operator may manipulate and perform tasks with implement 16 and/or to see the worksite so that the operator may steer and propel machine 12. It is contemplated that the operator may be able to directly see various portions of machine 12, but may not be able to directly see the wheels 14 from within cab 18 because wheels 14 may be, for example, blocked by fenders (not shown) and/or other components of machine 12. It is also contemplated that wheels 14 may be arranged relative to a given one of the operator sight paths through frame 26. For example, a first wheel may be disposed on a first side of machine 12 on a first side of a given operator sight path and a second wheel may be disposed on a second side of machine 12 on a second side of a given operator sight path.
One or more traction slip indicators 28 may be disposed within cab 18. Indicators 28 may include visual indicators, audible indicators, and/or vibratory indicators configured to be selectively activated to indicate an amount or type of traction slip. As described in more detail below, indicators 28 may be selectively activated by controller 32 to produce a repeating pattern indicative of the sensed traction slip that machine 12, and in particular wheels 14, may be experiencing. For example, as discussed in more detail below, the repeating pattern may visually, audibly, and/or vibrationally communicate the amount and/or direction of the traction slip that wheels 14 may be experiencing. It is contemplated that indicator 28 may be disposed within cab 18 such that given ones of indicators 28 are disposed on a first side of a given operator sight path and other ones of indicators 28 are disposed on a second side of the given operator sight path. Such indicators may respectively correspond with the wheels that are similarly disposed on first and second sides of the given operator sight path.
The visual indicators may include, for example, multiple sets of indicator lights 28a, 28b, 28c, 28d disposed on frame 26 at a periphery of one or more operator sight paths through a window. Each set of indicator lights 28a, 28b, 28c, 28d may include a plurality of individual lights arranged in a series. As shown in
The audible indicators may include, for example, a plurality of speakers 28e, 28f disposed on frame 26 and configured to produce and broadcast an audible alarm or other sound that can be heard by an operator. It is contemplated that the audible indicators may include any conventional speaker, may be any size, and may be configured to produce any type of sound.
The vibratory indicators may include, for example, one or more sets of vibration modules 28g, 28h disposed on or within seat 20. Each set of vibration modules may include a plurality of vibration elements arranged in series and may, for example, be disposed in the seat portion (as shown in
Controller 32 may embody a computer having a single microprocessor or multiple microprocessors. Numerous commercially available microprocessors may be configured to perform the functions of controller 32. Controller 32 may readily embody a general machine microprocessor capable of controlling numerous machine functions. Various circuits may be associated with controller 32, such as power supply circuitry, signal conditioning circuitry, data acquisition circuitry, signal output circuitry, signal amplification circuitry, and other types of circuitry known in the art. In particular, controller 32 may include one or more algorithms, decision logic sequences, and/or other programming capabilities to monitor and determine traction device slip relative to a surface of the worksite, as will be described in more detail below.
Gear shifter sensor 34 may embody a position sensor configured to determine and generate an output indicative of the selected drive operation of machine 12. For example, gear shifter sensor 34 may include one or more sensors 34a, 34b configured to monitor one or more of operator controls 22, e.g., a pedal or a lever, and generate one or more signals indicative of the drive direction of machine 12 as selected by an operator. It is contemplated that gear shift sensor 34 may monitor a pedal, joystick, hand lever, or other type of gear shift mechanism configured to selectively control machine 12 in forward or reverse directions. As shown in
Traction device sensor 36 may embody a velocity sensor configured to determine and generate an output indicative of the driven speed of one or more of wheels 14. For example, traction speed sensor 36 may be disposed adjacent a driven component, e.g., a sprocket (not referenced), axle (not referenced), or a transmission drive shaft (not referenced), or any other component of machine 12 configured to apply a drive force, e.g., a torque, to one or more wheels 14. Traction device sensor 36 may be configured generate one or more signals indicative of the speed of the driven wheels of machine 12 as selected by an operator. Such a speed is generally referred to as “driven speed.” It is contemplated that traction device sensor 36 may include multiple velocity sensors respectively configured to determine the driven speed of each of wheels 14.
Surface speed sensor 38 may embody a radar sensor configured to determine and generate an output indicative of the speed of machine 12 relative to a surface of the worksite on which machine 12 is propelled. For example, surface speed sensor 38 may be configured to send and receive electromagnetic waves to and from the surface on which machine 12 is propelled and generate one or more signals indicative of the actual speed that machine 12 is driven relative to the surface. Such a speed is generally referred to as “ground speed” and may not be the same as the driven speed of wheels 14. That is, one or more of wheels 14 may be driven at a first speed, as desired by the operator, and machine 12 may be propelled relative to the surface at a second speed, less than the first, such that the driven wheels 14 slip relative to the surface.
This difference between the driven speed and the ground speed may be due to the terrain and worksite conditions. Traction slip may be a result of the operator supplying too much power to one of more of wheels 14 and/or resistance caused by implement 16 engaging material on the worksite. For example, implement 16 may apply a force on machine 12 as a function of the friction between implement 16 and material in the worksite thus resisting movement of machine 12 as propelled by wheels 14. Controller 32 may determine the traction slip by comparing the driven speed of one or more of wheels 14 as sensed by traction speed sensor 36 with the ground speed of machine 12 as sensed by surface speed sensor 38. In addition, controller 32 may determine the direction of slip, e.g., forward or reverse, as sensed by gear shift sensor 34. It is contemplated that controller 32 may determine traction slip by any method or manner known in the art.
Controller 32 may be connected to indicators 28 and may be configured to selectively activate one or more of the visual indicators, the audible indicators, or the vibratory indicators in a pattern indicative of the sensed traction slip. For example, controller 32 may selectively send output signals to one or more of the individual lights to selectively illuminate one or more of multiple sets of indicator lights 28a, 28b, 28c, 28d in respective repeating patterns. Controller 32 may selectively send output signals to one or more of the speakers of audible indicators 28e, 28f to selectively broadcast sounds, e.g., a series of beeps or tones, in respective repeating patterns. Controller 32 may selectively send output signals to one or more of the vibration elements mounted in seat 20 to selectively vibrate the multiple sets of vibration modules 28g, 28h in respective repeating patterns.
It is contemplated that one or more of wheels 14 may be driven and that one driven wheel may experience slip at substantially the same time as another driven wheel is experiencing slip, wherein the respective slip is different. As such, controller 32 may be configured to respectively activate some of indicators 28 in a first pattern indicative of the traction slip sensed for one of the slipping wheels and selectively activate another of the indicators 28 in a second pattern indicative of the traction slip sensed for the other one of the indicators 28, the second pattern being different from the first pattern.
The repeating pattern of indicators 28 may be indicative of the amount of the sensed traction slip. For example, for a relatively low amount of slip, the repeating pattern, e.g., the selectively illuminated lights, selectively broadcast sounds, and/or the selectively vibrated elements, may be relatively slow as compared to when a relatively high amount slip is sensed. That is, the repeating pattern may be repeated at a relatively faster frequency for relatively higher sensed traction slip. It is contemplated that the pattern may be more or less intense, i.e., brighter or dimmer illumination, louder or quieter broadcast sounds, and/or more or less vibration, to indicate a relatively greater or smaller amounts of traction slip.
In addition, the number of lights, number of broadcast sounds, and/or the number of vibration elements that are selectively activated may be varied to indicate the amount of sensed traction slip. For example, for a relatively low amount of sensed slip, less than all of the lights or vibration modules, and a fewer number of broadcast sounds may be activated and repeated in the pattern as compared to when a relatively high amount of traction slip is sensed. It is also contemplated that, as shown with directional arrows in
The traction slip indicator may be applicable to any driven machine. The disclosed method and apparatus may more readily indicate traction slip to an operator via one or more visual, audible, and/or vibratory indicators. In addition, the disclosed system may indicate the type and amount of slip by selectively activating one or more indicators in a pattern indicative of the slip. Because the visual indicators may be disposed at the periphery of an operators line of sight, the operator may recognize slip is occurring without significantly diverting attention from operating a work tool or driving the machine. Moreover, the use of audible and/or vibratory indicators may also notify an operator of traction slip without diverting the operator's line of sight.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed traction slip indicator. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed method and apparatus. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims.
