Actuator Calibration Based on Fluid Level in a Fluid Tank

Abstract

A calibration system is disclosed. The calibration system may include: a sensor configured to measure a fluid level in a fluid tank of a machine; an actuator that, when actuated, affects the level of the machine; and a controller. The controller may be configured to: command the actuator to actuate at a current; receive, during and after commanding the actuator to actuate, information identifying the fluid level in the fluid tank from the sensor; determine whether there is a change in the fluid level in the fluid tank based on the information identifying the fluid level in the fluid tank; and set a starting current of the actuator at the current based on determining whether there is a change in the fluid level in the fluid tank.

Description

Technical Field

[0001] The present disclosure generally relates to actuator calibration and, for example, to actuator calibration based on the fluid level of a fluid tank. Background Art

[0002] A machine may include one or more components that are movable by actuation. For example, a cold planer may include a plurality of legs that may be raised or lowered by actuating corresponding valves (e.g., electrohydraulic valves) that control the flow of hydraulic fluid to the plurality of legs. Generally, a controller of the machine may initiate movement of a component by commanding an actuator associated with the component at a particular start current. For example, the start current may be a cracking current that causes the actuator to open (e.g., crack) a valve that controls the flow of hydraulic fluid to the component. However, in some cases, due to wear of the actuator or valve, the start current commanded to the actuator may not correspond to the cracking current because the actuator operates outside of specified tolerances, etc. As a result, the component may lack proper responsiveness to operator commands.

[0003] U.S. Patent No. 9,133,586, issued September 15, 2015 to BOMAG GmbH (“the ’586 patent”), discloses an attempt to balance a construction machine to prevent tipping. Specifically, the ’586 patent discloses a pressure measuring device that is deployed to an actuator of a construction machine and is designed to determine a value of the pressure applied to the actuator. The ’586 patent indicates that the monitored pressure value represents a measure of the degree of tipping of the construction machine.

[0004] Although the pressure measuring device of the ’586 patent can achieve monitoring of the degree of tipping of a construction machine, the ’586 patent does not address calibration of the start current of the actuator. In addition, the ’586 patent does not indicate that the degree of tipping can be monitored based on the fluid level of a fluid tank of the construction machine. Instead, the ’586 patent describes using a pressure measuring device to monitor the degree of tipping, which introduces additional components that may wear or fail.

[0005] The calibration system of the present disclosure solves one or more of the above problems and / or other problems in the prior art. Summary of the Invention

[0006] According to some embodiments, a method may include: commanding, by a controller of a machine, an actuator of the machine to actuate at a current, the actuator affecting the level of the machine when actuated; determining, by the controller, whether there is a change in the fluid level in a fluid tank of the machine after commanding the actuator to actuate; and setting, by the controller, an initial current of the actuator at the current based on determining whether there is a change in the fluid level in the fluid tank.

[0007] According to some embodiments, a calibration system may include: a sensor configured to measure a fluid level in a fluid tank of a machine; an actuator that, when actuated, affects the level of the machine; and a controller configured to: command the actuator to actuate at a current; receive, during and after commanding the actuator to actuate, information identifying the fluid level in the fluid tank from the sensor; determine whether there is a change in the fluid level in the fluid tank based on the information identifying the fluid level in the fluid tank; and set a starting current of the actuator at the current based on determining whether there is a change in the fluid level in the fluid tank.

[0008] According to some embodiments, a machine may include a component controlled by an actuator that, when actuated, affects the level of the machine; a fluid tank configured to hold fluid for the machine; and a controller configured to: command the actuator to actuate at a current; determine whether there is a change in the position of the component based on determining whether there is a change in the fluid level in the fluid tank after commanding the actuator to actuate; and set a starting current of the actuator at the current based on determining whether there is a change in the fluid level in the fluid tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a diagram of an exemplary machine described herein.

[0010] Figure 2 is a diagram of an exemplary calibration system described herein.

[0011] Figure 3 is a flowchart of an exemplary process for actuator calibration based on the fluid level of a fluid tank. DETAILED DESCRIPTION

[0012] Figure 1 is a diagram of an exemplary machine 100. As Figure 1 shown, machine 100 is embodied as a cold planer. Alternatively, machine 100 may be a rotary mixer, a paver, or another machine that includes a component controlled by an actuator that, when actuated, causes machine 100 (e.g., a machine with telescoping legs) to tilt.

[0013] Machine 100 includes a plurality of ground engaging members 104 to propel machine 100 over a road surface 106. Although Figure 1 two ground engaging members 104 are shown, machine 100 may include four ground engaging members 104 located at the right front, left front, right rear, and left rear of machine 100 relative to the direction of travel of machine 100. Additionally, although ground engaging members 104 are shown in Figure 1Shown as including tracks, the ground engaging members 104 may alternatively or additionally include wheels.

[0014] A plurality of ground engaging members 104 are connected to a frame 108 of the machine 100 by a plurality of hydraulic legs 110. Each hydraulic leg 110 is associated with an actuator (e.g., a solenoid actuator) that controls the position (e.g., height) of the hydraulic leg 110. For example, the actuator may control a valve (e.g., an electrohydraulic valve), and the valve controls the flow of hydraulic fluid to the hydraulic leg 110 to extend or retract the hydraulic leg 110. The actuators for the hydraulic legs 110 may operate independently of each other. For example, the hydraulic legs 110 on the left side of the machine 100 may extend further than the hydraulic legs 110 on the right side of the machine 100, causing the machine 100 to tilt to the right relative to the road surface 106.

[0015] A frame 108 of the machine 100 supports an operator area 112. The operator area 112 includes steering command elements 114 (e.g., a steering wheel, a joystick, a handle, etc.) and a control panel 116. The control panel 116 includes a user interface unit 118 configured to receive input from an operator of the machine 100. The user interface unit 118 communicates with a controller 120 of the machine 100, and the controller is configured to transmit control signals to one or more systems of the machine 100. The one or more systems may include a plurality of ground engaging members 104, a milling system 124, a conveyor system 126, a ventilation system 128, and / or an engine 130.

[0016] The engine 130 supplies power to the plurality of ground engaging members 104 to propel the machine 100. Such propulsion may be achieved by driving a hydraulic pump (not shown) with the output of the engine 130. The hydraulic pump supplies high-pressure hydraulic fluid to individual electric motors (not shown) associated with the plurality of ground engaging members 104. The engine 130 also supplies power to the milling system 124 to rotatably drive a milling drum 132 of the milling system 124 to perform a milling operation on the road surface 106.

[0017] The milling system 124 is supported on the frame 108 and uses the milling drum 132 to facilitate milling the road surface 106. The milling drum includes a plurality of cutting tools 134 (e.g., circumferentially arranged around the milling drum 132). The milling drum 132 rotates when receiving power from the engine 130, such that the plurality of cutting tools 134 repeatedly contact the road surface 106 to break one or more layers of material from the road surface 106. The hydraulic legs 110 may act as telescoping actuators configured to raise and lower the milling system 124 relative to the plurality of ground engaging members 104 to control the depth cut by the milling system 124.

[0018] The conveyor system 126 discharges the material generated by removing one or more layers of the road surface 106 from the machine 100. The conveyor system 126 includes at least one conveyor belt. For example, the conveyor system 126 may include a lower conveyor belt 136 and an upper conveyor belt 138 positioned adjacent to the lower conveyor belt 136. The lower conveyor belt 136 collects the material from the milling operation and conveys the material to the upper conveyor belt 138, which conveys the material to the discharge location.

[0019] The machine 100 further includes a water tank 140 supported on the frame 108. The water tank 140 may be positioned below the hood (not shown) of the machine 100 and near the milling system 124 and the conveyor system 126. The water tank 140 is in communication with at least one water nozzle 142 to selectively dispense the water stored in the water tank 140 toward the milling drum 132 and the plurality of cutting tools 134 of the milling system 124. The water tank 140 includes a sensor 144 configured to measure the water level of the water tank 140. For example, the sensor 144 may be a level sensor. The machine 100 may include additional fluid tanks and associated fluid level sensors, such as a diesel exhaust fluid (DEF) tank and associated DEF level sensor, a fuel tank and associated fuel level sensor, and so on.

[0020] The controller 120 (e.g., an electronic control module (ECM)) may include one or more memories and one or more processors that implement operations associated with actuator calibration based on the fluid level of a fluid tank (e.g., the water tank 140) of the machine 100, as described in connection with Figure 2 For example, the controller 120 may be configured to command the actuator to actuate at a current, determine whether there is a change in the fluid level in the fluid tank of the machine, and set the starting current of the actuator at that current based on determining whether there is a change in the fluid level in the fluid tank.

[0021] As described above, by way of Figure 1 For example. Other examples may be different from those described in connection with Figure 1 For example.

[0022] Figure 2 is a diagram of an exemplary calibration system 200. As shown in Figure 2 The calibration system 200 includes a user interface unit 118, a controller 120, one or more sensors 202, and one or more actuators 204. The controller 120 may communicate with the user interface unit 118, the sensors 202, and the actuators 204 via a wired connection or a wireless connection.

[0023] The controller 120 can receive an operator command to execute a calibration procedure for the actuator 204 from the user interface unit 118. That is, the operator can request calibration of the actuator 204 via the user interface unit 118. In some embodiments, the controller 120 can determine (e.g., without receiving an operator command) to execute the calibration procedure for the actuator 204, for example, based on detecting mis-calibration in one or more of the actuators 204, based on expiration of a threshold period since the previous calibration of the actuator 204, etc. Additionally or alternatively, the controller 120 can execute the calibration procedure for the actuator 204 based on an operation performed at the user interface unit 118 (e.g., during operation of the machine 100). For example, the controller 120 can execute the calibration procedure for the actuator 204 when the operator is manipulating an actuator command element of the user interface unit 118. Before executing the calibration procedure, the controller 120 can command the actuator 204 to an intermediate position (e.g., a horizontal position).

[0024] The actuator 204 that can be controlled by a solenoid can control a valve that controls the flow of hydraulic fluid to components of the machine 100. As Figure 2 shown, each actuator 204 is associated with a respective hydraulic leg 110 of the machine 100. Thus, the actuator 204 affects the level of the machine 100 when actuated (e.g., affects the level of the frame 108 or the level of a fluid tank (e.g., the water tank 140)). For example, the actuator 204 can tilt the machine 100, level the machine 100, etc. The actuator 204 can be associated with another actuatable component of the machine 100 (e.g., a component that affects the level of the machine 100 when actuated). For example, the component can be a leg (e.g., a leveling leg), and the actuator 204 controls the position of the leg; the component can be an arm (e.g., a horizontally extending arm, a boom, an excavator arm, etc.), and the actuator 204 controls the position of the arm; the component can be an implement (e.g., a grader blade, a bucket, a tipper, etc.), and the actuator 204 controls the position of the implement, etc.

[0025] According to the calibration procedure, for each actuator 204, the controller 120 can command the actuator 204 to actuate at an increasing current over time until a change in the level of the machine 100 (e.g., tilting) is detected, thereby indicating the starting current (e.g., cracking current) of the actuator 204. For example, the controller 120 can command the actuator 204 to actuate at a current, and the controller 120 can determine whether the current causes actuation of the actuator 204 (e.g., causes the actuator 204 to open the valve) based on the fluid level in the fluid tank of the machine 100. That is, the controller 120 can determine that the current causes actuation of the actuator 204 when a change in the fluid level is detected (e.g., relative to a previous fluid level measurement).

[0026] For example, the controller 120 can monitor the fluid level while increasing the current commanded to the actuator 204 to detect a change in the fluid level. As an example, the controller 120 can command the actuator 204 to actuate at a current, and if no change in the fluid level is detected, the controller 120 can command the actuator 204 to actuate at an increased current, and so on. Although there is no actual change in the amount of fluid in the fluid tank, a change in the fluid level is detected due to a change in the level of the machine 100 caused by the actuation of the actuator 204.

[0027] The controller 120 can receive information identifying the fluid level in the fluid tank from a sensor 202 associated with (e.g., located within) the fluid tank. In some embodiments, the fluid tank can correspond to the water tank 140, and the sensor 202 can correspond to the sensor 144. Additionally or alternatively, the fluid tank can be another fluid tank of the machine 100, such as a DEF tank, a fuel tank, etc. Thus, the controller 120 can receive fluid level information from a plurality of sensors 202 respectively associated with a plurality of fluid tanks (e.g., one or more water tanks, DEF tanks, fuel tanks, etc.) of the machine 100.

[0028] The fluid level information received from the sensor 202 may not be filtered, or may be filtered less than the fluid level information received by the controller 120 regarding operations unrelated to the calibration procedure. Additionally or alternatively, the controller 120 may not perform filtering of the fluid level information, or may perform less filtering on the fluid level information than on the level information regarding operations unrelated to the calibration procedure. Filtering (e.g., regarding operations unrelated to the calibration procedure) can be performed to standardize the fluid level information, remove noise data from the fluid level information, etc.

[0029] The controller 120 can determine whether the current causes the actuation of the actuator 204 based on the fluid level information received from a single sensor 202 or from a plurality of sensors 202. For example, the controller 120 can aggregate the fluid level information received from the plurality of sensors 202 to determine whether the current causes the actuation of the actuator 204. As an example, the controller 120 can determine that the current causes the actuation of the actuator 204 when a threshold number of the plurality of fluid tanks report fluid level information indicating a change in the fluid level.

[0030] In addition, the controller 120 can select a single sensor 202 from multiple sensors 202, and the single sensor will be used to determine whether a current causes actuation of the actuator 204. For example, the controller 120 can determine that the fluid level in the fluid tank satisfies a capacity range (e.g., 25% to 75%, 40% to 60%, or 45% to 55%) based on determining that the sensor 202 is eccentric in the fluid tank (e.g., according to the configuration of the fluid tank or the machine 100), and / or determine that the fluid level is static (e.g., the fluid level does not change, or changes by an amount that satisfies a threshold due to movement of the machine 100 that is not related to the calibration procedure) to select the single sensor 202. The controller 120 can also select a subset of the multiple sensors 202, and this subset will be used to determine in a similar manner whether a current causes actuation of the actuator 204. In other words, if the sensor 202 is eccentric in the fluid tank, if the fluid level in the fluid tank satisfies the capacity range, and / or if the fluid level is static, then the controller 120 can use the fluid level information from the sensor to determine whether a current causes actuation of the actuator 204.

[0031] Based on determining that a current causes actuation of the actuator 204 (e.g., detecting a change in the fluid level), the controller 120 can set (e.g., configure, store, save, etc.) the starting current (e.g., cracking current) of the actuator 204 at that current. The starting current is the current that the controller 120 commands the actuator 204 when the operator subsequently requests actuation of the actuator 204. After performing a calibration procedure on the actuator 204, the controller 120 can repeat the calibration procedure for different position movements of the actuator 204 and / or for one or more additional actuators 204. For example, the controller 120 can perform a calibration procedure for raising the left front hydraulic leg 110 of the machine 100, lowering the left front hydraulic leg 110, raising the right front hydraulic leg 110, lowering the right front hydraulic leg 110, raising the rear hydraulic leg 110, and / or lowering the rear hydraulic leg 110.

[0032] As described above, take Figure 2 as an example. Other examples can be different from those described in conjunction with Figure 2 what is described.

[0033] Figure 3 is a flowchart of an exemplary process 300 for actuator calibration based on the fluid level in the fluid tank. Figure 3 One or more process blocks of can be executed by a controller (e.g., the controller 120). Additionally or alternatively, Figure 3 One or more process blocks of can be executed by another device or a set of devices separate from or including the controller, such as components inside or outside another device or the machine 100.

[0034] As Figure 3As shown in, process 300 may include commanding an actuator of a machine to actuate at a current where the actuator, when actuated, affects the level of the machine (block 310). For example, a controller (e.g., using a processor, memory, output components, communication interfaces, etc.) may command the actuator of the machine to actuate at a current as described above. The actuator may be associated with a component of the machine, and the actuator, when actuated, affects the level of the machine. For example, the actuator may control (e.g., based on a control valve that controls the flow of hydraulic fluid) at least one of the position of the legs of the machine, the position of the arms of the machine, or the position of the implements of the machine. The actuator may be commanded to actuate based on receiving an operator command to perform calibration of the actuator.

[0035] As Figure 3 Also shown in, process 300 may include, after commanding the actuator to actuate, determining whether there is a change in the fluid level in a fluid tank of the machine (block 320). For example, a controller (e.g., using a processor, memory, input components, communication interfaces, etc.) may determine whether there is a change in the fluid level in a fluid tank of the machine as described above after commanding the actuator to actuate. The fluid tank may be one of a plurality of fluid tanks of the machine, in which case process 300 may include determining whether there is a change in the respective fluid levels in the plurality of fluid tanks.

[0036] Determining whether there is a change in the fluid level may be based on measurements from a sensor associated with the fluid tank. The sensor may have an eccentric position in the fluid tank. The fluid tank may be a water tank, a fuel tank, or a DEF tank.

[0037] In some embodiments, process 300 includes selecting a fluid tank to determine whether there is a change in the fluid level based on determining that the sensor eccentricity or the fluid level of the fluid tank meets a range.

[0038] As Figure 3 Also shown in, if it is determined that there is no change in the fluid level (block 330 - no), then process 300 may include returning to block 310. In this case, the commanded current may be increased relative to the previous iteration.

[0039] If it is determined that there is a change in the fluid level (block 330 - yes), then as Figure 3 Also shown in, process 300 may include setting a starting current of the actuator at the current based on determining a change in the fluid level in the fluid tank (block 340). For example, a controller (e.g., using a processor, memory, storage components, etc.) may set the starting current of the actuator at the current based on determining that there is a change in the fluid level in the fluid tank as described above. The starting current of the actuator may be set at the current based on determining that the fluid level meets a range.

[0040] Although Figure 3An exemplary block of process 300 is shown, but in some embodiments, process 300 may include more blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in Figure 3 Additionally or alternatively, two or more of the blocks of process 300 may be executed in parallel.

[0041] Industrial applicability

[0042] The disclosed calibration system can be used with any machine that includes components controlled by an actuator that, when actuated, affects the level of the machine. For example, the calibration system can be used with a machine that includes a leg leveling system employing one or more telescoping legs. The calibration system enables calibration of the starting current of the actuator of the machine based on the fluid level in the fluid tank of the machine. In this way, sensors that may fail and / or may be difficult to replace and that are associated with the actuator are not required to calibrate the actuator. Additionally, the fluid level can provide an accurate indication of the cracking current available to the actuator, thereby improving the responsiveness of the actuator.

Claims

1. A method, comprising: commanding an actuator of a machine by a controller of the machine to actuate at a current, wherein the actuator affects the level of the machine when actuated; determining by the controller whether there is a change in a fluid level in a fluid tank of the machine after commanding the actuator to actuate; and setting, by the controller, a starting current of the actuator at the current based on determining whether there is a change in the fluid level in the fluid tank.

2. The method according to claim 1, wherein the actuator controls at least one of the following: a position of a leg of the machine; a position of an arm of the machine; or a position of an implement of the machine.

3. The method according to any one of claims 1-2, wherein determining whether there is a change in the fluid level comprises: monitoring the fluid level while increasing the current; and detecting a change in the fluid level based on monitoring the fluid level.

4. The method according to any one of claims 1-3, further comprising: receiving an operator command to perform calibration on the actuator before commanding the actuator to actuate.

5. The method according to any one of claims 1-4, further comprising: selecting the fluid tank to determine whether there is a change in the fluid level based on determining that a sensor of the fluid tank is eccentric or the fluid level meets a range.

6. A calibration system, comprising: a sensor configured to measure a fluid level in a fluid tank of a machine; an actuator that affects the level of the machine when actuated; and a controller configured to: command the actuator to actuate at a current; receive, during and after commanding the actuator to actuate, information identifying the fluid level in the fluid tank from the sensor; determine whether there is a change in the fluid level in the fluid tank based on the information identifying the fluid level in the fluid tank; and set, based on determining whether there is a change in the fluid level in the fluid tank, a starting current of the actuator at the current.

7. The calibration system according to claim 6, wherein the sensor has an eccentric position in the fluid tank.

8. The calibration system according to any one of claims 6-7, wherein the controller is further configured to: command the actuator to actuate at an increasing current based on determining that there is no change in the fluid level.

9. The calibration system according to any one of claims 6-8, wherein the fluid tank is at least one of the following: a water tank; a fuel tank; or a diesel exhaust fluid tank.

10. The calibration system according to any one of claims 6-9, wherein the fluid tank is one of a plurality of fluid tanks of the machine, and wherein the controller is configured to determine whether there is a change in a corresponding fluid level in the plurality of fluid tanks.

Images