Patent Grant
9441348
This disclosure relates generally to a hydraulic system and, more particularly, to a hydraulic system that compensates for the operator's skill level.
Machines such as, for example, wheel loaders, track-type tractors, motor graders, dozers, and other mobile machines may be used to perform a variety of operations associated with an industry such as mining, farming, construction, transportation, or any other industry. Operators of such machines may have a variety of skill levels. It may take a significant amount of training on a machine before an operator may be characterized as an expert or even an intermediate operator.
Machine operators are often trained in computer-based simulators and perform on-machine training exercises prior to performing actual work-related operations. While these methods may provide a basic level of operational exposure, they may not provide an environment that completely prepares the operator for actual “real-world” work experiences associated with a job site. Thus, many inexperienced machine operators may require additional on-the-job training in machine operation.
JPH01127731A discloses a method in which a controller for an operating valve of an earth-moving machine compensates input signals from an operating lever of the machine based on whether a mode switch is activated. The mode switch can be activated for inexperienced machine operators in order to provide compensation of the input signals from the operating lever. With more experienced machine operators, the mode switch is deactivated and no compensation is applied to the input signals from the operator. While this method can help inexperienced operators operate a machine more effectively, it is dependent upon the operator selecting the proper mode for his skill level.
In one aspect, the disclosure describes a hydraulic system for a machine including a first cylinder movable between extended and retracted positions in response to flow of hydraulic fluid into and out of the cylinder; a pump configured to supply pressurized hydraulic fluid to the first cylinder; and an operator input device for entering a commanded rate of flow of hydraulic fluid to the first cylinder. A control valve is operatively connected between the pump and the first cylinder. The control valve is configured to selectively place the pump in fluid communication with the first cylinder and control the flow of hydraulic fluid into and out of the first cylinder. A sensor is configured and arranged to provide signals relating to a first operating characteristic of the machine. A controller is in communication with the operator input device, the control valve and the sensor. The controller is configured to determine the operating characteristic of the machine; store a first threshold for the first operating characteristic of the machine; and determine a skill level of an operator of the machine based on a comparison of the first operating characteristic of the machine and the first threshold. The controller determines an adjusted hydraulic fluid flow rate based on the operator skill level and the commanded rate of flow that is below the commanded rate of flow if the skill level of the operator is below a predetermined skill level. The controller directs the control valve to provide hydraulic fluid to the first cylinder at the adjusted hydraulic fluid flow rate.
In another aspect, the disclosure describes a method of controlling hydraulic fluid flow relative to a cylinder of a machine. The method includes the steps of receiving a commanded rate of flow of hydraulic fluid to the cylinder from an operator through an operator input device; determining a first operating characteristic of the machine; and determining a skill level of the operator of the machine based on a comparison of the first operating characteristic to a first threshold for the operating characteristic. An adjusted hydraulic fluid flow rate is determined based on the operator skill level and the commanded rate of flow that is below the commanded rate of flow if the skill level of the operator is below a predetermined skill level. Hydraulic fluid is directed to the cylinder at the adjusted hydraulic fluid flow rate.
In yet another aspect, the disclosure describes a machine including a prime mover and a cylinder movable between extended and retracted positions in response to flow of hydraulic fluid into and out of the cylinder. An implement is operatively connected to the cylinder. A pump is operatively connected to the prime mover and configured to supply pressurized hydraulic fluid to the cylinder. An operator input device is used for entering a commanded rate of flow of hydraulic fluid to the cylinder. A control valve is operatively connected between the pump and the cylinder. The control valve is configured to selectively place the pump in fluid communication with the cylinder and control the flow of hydraulic fluid into and out of the cylinder. A sensor is configured and arranged to provide signals relating to a first operating characteristic of the machine. A controller is in communication with the operator input device, the control valve and the sensor. The controller is configured to determine the operating characteristic of the machine; store a first threshold for the first operating characteristic of the machine; and determine a skill level of an operator of the machine based on a comparison of the first operating characteristic of the machine and the first threshold. The controller determines an adjusted hydraulic fluid flow rate based on the operator skill level and the commanded rate of flow that is below the commanded rate of flow if the skill level of the operator is below a predetermined skill level. The controller directs the control valve to provide hydraulic fluid to the cylinder at the adjusted hydraulic fluid flow rate.
This disclosure generally relates to a system and method for adjusting operation of a hydraulic system based on the operator's skill level. Referring to
The implement support portion 12 includes a linkage 20 having one or more lift arms 21 pivotally connected to the implement support portion 12 at first pivot joint 23. A work implement such as bucket 24 may be pivotally mounted at a distal end 25 of the lift arms 21 at a second pivot joint 26. A curl lever 27 may be pivotally mounted on curl lever support member 22 of implement support portion 12 with a first end (not shown) connected to a curl link member 28 that is pivotally connected to bucket 24. With this configuration, rotation of the curl lever 27 results in curling or tilting of the bucket 24 about the second pivot joint 26.
The machine 10 may include a system such as a hydraulic system generally indicated at 30 for operating various systems and components of the machine. A pair of steering cylinders 31 (only one being visible in
Referring to
The machine 10 may include a control system 40, as shown generally by an arrow in
The controller 41 may be an electronic controller that operates in a logical fashion to perform operations, execute control algorithms, store and retrieve data and other desired operations. The controller 41 may include or access memory, secondary storage devices, processors, and any other components for running an application. The memory and secondary storage devices may be in the form of read-only memory (ROM) or random access memory (RAM) or integrated circuitry that is accessible by the controller. Various other circuits may be associated with the controller 41 such as power supply circuitry, signal conditioning circuitry, driver circuitry, and other types of circuitry.
The controller 41 may be a single controller or may include more than one controller disposed to control various functions and/or features of the machine 10. The term “controller” is meant to be used in its broadest sense to include one or more controllers and/or microprocessors that may be associated with the machine 10 and that may cooperate in controlling various functions and operations of the machine. The functionality of the controller 41 may be implemented in hardware and/or software without regard to the functionality. The controller 41 may rely on one or more data maps relating to the operating conditions and the operating environment of the machine 10 and the work site 101 that may be stored in the memory of controller. Each of these data maps may include a collection of data in the form of tables, graphs, and/or equations.
The control system 40 and the controller 41 may be located on the machine 10 or may be distributed with components also located remotely from the machine such as at a command center (not shown). The functionality of control system 40 may be distributed so that certain functions are performed at machine 10 and other functions are performed remotely. In such case, the control system 40 may include a communications system such as wireless network system (not shown) for transmitting signals between the machine 10 and a system located remote from the machine such as at the command center.
The machine 10 may be equipped with a plurality of machine sensors that provide data indicative (directly or indirectly) of various operating parameters of the machine and/or the operating environment in which the machine is operating. The term “sensor” is meant to be used in its broadest sense to include one or more sensors and related components that may be associated with the machine 10 and that may cooperate to sense various functions, operations, and operating characteristics of the machine and/or aspects of the environment in which the machine is operating.
A position sensing system 42, as shown generally by an arrow in
An articulating joint position sensor 45, as shown generally by an arrow in
A lift position sensor 47, as shown generally by an arrow in
A curl position sensor 48, as shown generally by an arrow in
Other types of sensors such as, for example, rotary potentiometers may be used rather than cylinder displacement sensors to determine the relative angles between the pivotable components (i.e., implement support portion 12 relative to base portion 11, lift arms 21 relative to implement support portion 12, and bucket 24 relative to lift arms 21). Additional sensors may be provided, if desired, to generate signals indicative of the relative angular velocity and angular acceleration between the pivotable components as they rotate about their pivot joints. In an alternate embodiment, the controller 41 may be configured to determine the relative angular velocity and angular acceleration based upon the signals from the different position sensors. For example, the controller 41 may monitor or determine the rate of change of the relative positions of the components to determine the angular velocity.
A simplified schematic of the hydraulic system 30 that may be used to direct movement of the work implement of the machine 10, in the case the bucket 24, is provided as
The cylinder 62 of
In the embodiment shown in
The controller 41 of the machine 10 may be configured to adjust the flow of hydraulic fluid to one or more of the cylinders controlling movement of the work implement based on a determination of the skill level of the operator. In particular, with reference to the embodiment of
The control system 40 including the controller 41 may be configured to determine the skill level of the operator automatically without any manual input by the operator or other personnel associated with work site. For example, the controller 41 may be configured to determine the skill level of the operator based on inputs from at least one sensor that is configured and arranged to provide signals relating to at least one operating characteristic of the machine 10. The sensor may be related to the one or more input devices 36 or be one or more machine sensor (for example, engine speed sensors, hydraulic pressure sensors and/or machine ground speed sensors), and/or implement position sensors (for example, the articulating joint sensor 45, displacement sensors 46, the lift position sensor 47 and curl position sensor 48). The controller 41 may further be configured to use these inputs with an algorithm that would be used to evaluate and log performance of the operator so as to determine the operators skill level. The controller 41 may also use other historical operating characteristic data in determining the skill level of the operator including historical data on operating characteristics associated with one or more components and/or subsystems of machine 10 such as, for example, machine location (via the position sensing system 42); fluid pressure, flow rate, temperature, contamination level, and or viscosity of a fluid; electric current and/or voltage levels; fluid (i.e., fuel, oil, etc.) consumption rates; loading productivity/efficiency (i.e., payload value, percent of maximum payload limit, payload history, payload distribution, etc.); transmission output ratio, slip, etc.; grade; traction data; scheduled or performed maintenance and/or repair operations; and any other suitable operation data. The controller 41 may use the data from these various sources in a comparison against predetermined thresholds that differentiate the various operator skill levels. For example, the thresholds may differentiate between expert and novice skill levels or expert, intermediate and novice skill levels. Additional delineations of skill level may also be provided. For each skill level, the controller 41 may provide a different adjustment to the hydraulic fluid flow commanded by the operator through the input device 36. For example, the controller 41 may make no adjustment to the commands issued by an expert operator, a first adjustment to commands issued by an intermediate operator and a relatively larger second adjustment to commands issued by a novice operator. The determination as to the skill level of the operator may be transmitted by the controller 41 to a remote location such as a command center.
One example of data that may be used by the controller 41 in determining the operator skill level may be data generated by the machine sensors relating to whether the operator is operating multiple cylinders simultaneously. For example, with respect to the illustrated embodiment, the controller 41 may use data from the curl position sensor 48 and the lift position sensor 47 to determine whether the lift cylinders 32 and the curl cylinder 33 are being moved simultaneously. Alternatively, the controller 41 could use signals from the respective input devices 36 associated with the lift cylinders 32 and the curl cylinder 33 to determine whether the operator is directing movement of both cylinders at the same time. In general, operators with a relatively higher skill level are able to operate two or more cylinders of the machine 10 simultaneously while operators with a relatively lower skill level tend to use the different cylinders one at a time. Accordingly, if the controller 41 determines that multiple cylinders are being used simultaneously by the operator, the controller 41 may determine that there is no need to limit or adjust the flow of hydraulic fluid to the cylinders that is commanded by the operator through the operator input device 36. Conversely, if the controller 41 determines that the cylinders are being used one at a time, the controller 41 may limit or adjust downward the flow of hydraulic fluid to the cylinders through the control valve 70 that is commanded by the operator through the operator input device 36. The controller 41 may be configured with thresholds that would allow the controller 41 to determine the extent to which operation of the cylinders one at a time in an operation would indicate that the operator has a relatively lower skill level.
Another example of data that may be used by the controller 41 in determining the skill level of the operator of the machine 10 is data reflecting how smoothly one or more cylinders of the machine are being operated. In general, if the cylinder 62 (e.g., the lift cylinders 32 and/or curl cylinders 33) is being operated in a stop-and-start manner resulting in jerky movements of the cylinder and the associated implement (e.g., the bucket 24), the controller 41 may determine that the operator has a relatively low skill level and apply an adjustment to the flow of hydraulic fluid to the cylinder 62 that is requested by the operator via manipulation of the control valve 70. On the other hand, if the cylinder 62 is consistently moved smoothly by the operator, the controller 41 may determine that the operator has a relatively higher skill level and adjustments to the flow of hydraulic fluid flow commanded by the operator are unnecessary. The data regarding the smoothness of the movement of the cylinder 62 may be generated using signals from the displacement sensor associated with the corresponding cylinder (e.g., the lift position sensor 47 and/or the curl position sensor 48). Alternatively or additionally, the data regarding smoothness of the movement of the cylinder 62 may be generated using signals from other sensors such as one or more accelerometers associated with the cylinder or the implement and/or sensors from which the velocity of the cylinder or the implement may be determined. The data regarding the smoothness of the movement of the cylinder 62 may also be generated based on signals from the input device 36 used by the operator. In particular, the controller 41 may determine that an operator has a relatively low skill level based on signals indicating quick stop-and-start movements of the input device 36. The controller 41 may be configured with thresholds that could be used by the controller to determine whether the cylinder 62 is being moved smoothly or in a stop-start fashion by the operator.
Another way in which to determine an operator's skill level is to break or segment a particular operation into a plurality of quantitatively measurable tasks with each of the tasks being measured against a desired threshold. In other words, an operation may be divided into a plurality of tasks that may be evaluated based upon desired positions and speeds of the machine 10 and its various components. The operator's performance for each task as well as the overall operation may be measured and used to determine the operator's skill level.
As an example, the machine 10, configured as a wheel loader, may be used to repeatedly dig into a pile of loose material 100 such as gravel or dirt with bucket 24, lift a bucket load of material, and subsequently move the bucket load of material to a desired location such as within a haul truck (not shown). The operation of digging into the pile of material and loading the bucket 24 may be segmented into a plurality of sequential tasks and the efficiency of each task may be measured based upon operating characteristics such as the relative or absolute positions and/or speeds of movement of the machine 10 and its various components (e.g., lift arms 21 and bucket 24). The operating characteristics may be compared to one or more desired thresholds to evaluate or rate the skill level of an operator for each task as well as for the entire operation.
The controller 41 may determine the extent to which the base portion 11 and the implement support portion 12 (i.e., the articulation angle 112) are aligned based upon data from the articulating joint position sensor 45 as described above. One or more thresholds in the form of a maximum desired misalignment or articulation angle 112 may be stored within controller 41. The controller 41 may be configured to compare the actual misalignment between the base portion 11 and the implement support portion 12 (i.e., the articulation angle 112) to one of the thresholds in order to evaluate or measure an operator's skill level.
The controller 41 may be configured to evaluate or monitor the articulation angle 112 when the bucket 24 engages the pile of material 100. To determine when the bucket 24 initially engages the pile of material 100, the controller 41 may utilize an implement load sensor system 51 indicated generally in
Other manners of determining when the bucket 24 is initially engaging the pile of material 100 are contemplated. For example, in alternate embodiments in which the machine propulsion and drivetrain mechanisms are hydrostatic or electric, implement load sensor system 51 may embody other sensors that detect a difference between output from the prime mover and other aspects of the propulsion and drivetrain mechanisms. In another alternate embodiment, the implement load sensor system 51 may utilize one or more pressure sensors (not shown) associated with one or more of the hydraulic cylinders to determine when the load on the bucket 24 initially increases relatively quickly indicating the initial engagement between the bucket and the pile of material 100.
Referring to
The controller 41 may determine whether an operator has “set the tires” by monitoring the angle of the lift arms 21 relative to the implement support portion 12 as they pivot or rotate about first pivot joint 23 based upon data from the lift position sensor 47 as described above. One or more desired thresholds may be stored within controller 41. The desired thresholds may include the extent to which the lift arms should be raised (e.g., expressed as an angle about first pivot joint 23 or a distance) as well as the timing in which the operation should begin relative to engagement of the pile of material 100 by the bucket 24. The controller 41 may be configured to compare the extent of actual movement of the lift arms 21 relative to the implement support portion 12 and its timing to the desired thresholds in order to evaluate or measure an operator's skill level.
The controller 41 may begin evaluating the operator's skill level upon determining engagement of the bucket 24 with the pile of material 100 as described above.
Additional quantitatively measurable tasks may be associated with the physical loading of the bucket 24 as it enters the pile of material 100. For example, it is generally desirable for the bucket 24 to enter the pile of material 100 at a desired angle relative to the ground or the pile of material, and it is generally desirable for the bucket to be curled and the lift arms 21 to be raised in a desired manner to maximize the efficiency of the bucket loading process. More specifically, it is generally desirable for the bucket 24 to enter the pile of material 100 with the lower surface 29 of the bucket generally parallel to the work surface 102 as depicted in
The controller 41 may determine the angle 114 (
The controller 41 may begin evaluating the operator's skill level upon determining engagement of the bucket 24 with the pile of material 100 as described above.
Additional quantitatively measurable tasks may also be associated with the specific manner in which the bucket 24 is loaded. When loading bucket 24, it is generally desirable for the machine to move forward with the bucket beginning to penetrate the pile of material 100 and then slightly curling the bucket or rotating it upward about second pivot joint 26 as depicted by arrow 115 in
In one example, poor or inefficient filling of the bucket 24 will occur if the bucket is curled too quickly about second pivot point 26 as the bucket engages the pile of material 100. When curling the bucket 24 too quickly, the angle of the bucket will be pointed somewhat upward so that the bucket does not effectively dig into the pile of material 100 as depicted in
The controller 41 may determine whether an operator has curled the bucket 24 too quickly based upon data from the curl position sensor 48, which may be used to determine the actual position of the bucket or the rate at which the bucket is rotating, as well as based upon data from the position sensor 43 as the machine 10 moves forward into the pile of material 100.
The controller 41 may begin evaluating the operator's skill level upon determining engagement of the bucket 24 with the pile of material 100 as described above. In one embodiment, the desired threshold set or stored within the controller 41 may include a desired amount of rotation of the bucket 24 based upon the distance that the machine 10 has moved once it has entered the pile of material 100. In another embodiment, the controller 41 may compare the rate at which the bucket 24 is rotating to a desired threshold.
In another example, poor or inefficient filling of the bucket 24 will occur if the bucket is curled and uncurled or “pumped” as the bucket is moved into the pile of material 100 as depicted in
The controller 41 may determine whether an operator is pumping the bucket 24 based upon data from the curl position sensor 48 as well as based upon data from the position sensor 43 as the machine 10 moves forward into the pile of material 100. The controller 41 may begin evaluating the operator's skill level upon engagement of the bucket 24 with the pile of material 100. The controller 41 may monitor the angle of the bucket 24 relative to the lift arms 21 and compare the amount or angle of uncurling of the bucket about second pivot joint 26, if any, to a threshold angle. In one embodiment, a single act of uncurling of the bucket 24 by more than a threshold angle may be an indication that the operator has a relatively low skill level. In another embodiment, multiple events of uncurling of the bucket 24 by more than a threshold angle as the machine 10 moves forward into the pile of material 100 may be an indication that the operator has a relatively low skill level.
In still another example, poor or inefficient filling of the bucket 24 will occur if the operator uses the lift arms 21 as a significant part of the bucket filling process rather than utilizing the curl cylinder 33 and the forward movement of the machine 10. When improperly using the lift arms 21, the operator may significantly raise the lift arms while only minimally curling the bucket 24. Excessive use of the lift arms 21 during the bucket loading process is generally undesirable as it will increase the time required to fill the bucket 24, may cause tire slip, and may cause the machine 10 to climb up the pile of material 100 which may damage the tires and put the machine in an unstable position.
The controller 41 may determine whether an operator is loading the bucket 24 using the lift arms 21 based upon data from the lift position sensor 47 as well as based upon data from the position sensor 43 as the machine 10 moves forward into the pile of material 100. The controller 41 may begin evaluating the operator's skill level upon engagement of the bucket 24 with the pile of material 100 and terminate the analysis once the machine 10 begins moving in reverse away from the pile of material. The controller 41 may monitor the angle of the lift arms 21 relative to the implement support portion 12 and compare movement of the lift arms about first pivot joint 23 to a threshold angle or amount of movement. In one embodiment, the controller 41 may be configured so that the lift arms 21 are only to be used while setting the tires as described above. In another embodiment, raising the lift arms 21 more than a threshold angle or distance may be an indication that the operator has a relatively low skill level.
In a further example, poor or inefficient filling of the bucket 24 may occur if the machine 10 is in second gear during the bucket filling process. In other words, it is generally desirable for the machine 10 to be in first gear as the bucket 24 engages the pile of material 100 and the bucket is filled. If the machine 10 is in second gear rather than first gear, the bucket 24 may be less likely to penetrate the pile of material 100 and therefore the bucket may not be filled as desired.
The controller 41 may determine whether the machine is in first gear or has been shifted into a state that will permit it to automatically shift from second gear to first gear based upon the status of an input device associated with the transmission (not shown) of the machine. In one embodiment, the controller 41 may begin evaluating the status of the transmission upon engagement of the bucket 24 with the pile of material 100. In another embodiment, it may be desirable for the operator to shift the transmission into first gear or into an auto-shift mode a predetermined time or distance before the bucket 24 engages the pile of material 100. In such case, the controller may 41 monitor the status of the transmission and compare the time of shifting to the time that the bucket 24 engages the pile of material to determine whether a shift was made within or outside the desired threshold.
As described above, a plurality of quantitatively measurable tasks may be performed as part of an operation to load a bucket 24 with material. The skill level with which the operation has been performed may be determined by evaluating whether the tasks are being performed within the desired thresholds. The controller 41 may be configured to store different thresholds for each task.
The controller 41 may analyze the quantitatively measurable tasks that make up an operation in order to rate or determine the skill level of the operator based on the quality of the entire operation.
Referring to
In decision step 130, the controller 41 proceeds to step 132 and directs hydraulic fluid (e.g., via the control valve 70) to the hydraulic device (e.g., the cylinder 62) at the commanded rate if it has been determined that the operator has a relatively high skill level. If the operator has a relatively low skill level, the controller proceeds from decision step 130 to step 134 and determines an adjusted hydraulic fluid flow rate based on the operator skill level and the commanded flow rate. Then in step 136 the controller directs (e.g., via the control valve 70) hydraulic fluid to the hydraulic device (e.g., the cylinder 62) at the adjusted flow rate, which typically would be less than the commanded flow rate.
The system and method of adjusting operation of a hydraulic system based on the operator's skill level of the present disclosure is applicable for use with any type of machine having a hydraulically operated implement and particularly those machines on which operators frequently require training. In particular, the slower hydraulic response produced with the disclosed system and method will allow a less skilled operator such as a novice operator to gain experience operating the machine using complex machine controls without causing undesired contact with other machines or obstacles or undue disturbance of the worksite. Because the system determines the skill level of the operator automatically, there is no need for the operator or other personnel at the work site to enter skill level information into the machine thereby eliminating the possibility that the operator will overrate his or her skill level with the machine.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.
Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5101627 | Fujii et al. | Apr 1992 | A |
| 20050246040 | Horkavi et al. | Nov 2005 | A1 |
| 20090132131 | Takeda | May 2009 | A1 |
| Number | Date | Country |
|---|---|---|
| 1-127731 | May 1989 | JP |
| 5-321296 | Dec 1993 | JP |
| 10-212740 | Aug 1998 | JP |
| 2986471 | Dec 1999 | JP |
