Wired position sensor

Abstract

Linear distance measuring system, comprising: an airtight chamber having a first coil, a second coil, a third coil, an intermediate cover and a cover, wherein the intermediate cover has a cylindrical projection configured to receive a slider.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a sensor for measuring distance in harsh environments. BACKGROUND AND OVERVIEW

[0002] Construction vehicles may be equipped to carry and manipulate physical loads. Some vehicles have a telescopic arm that can be used to move the load up, down, toward, or away from the vehicle. It may be desirable to know the position of the telescopic arm under different conditions (e.g., when the vehicle is switched on and during operation) to maintain vehicle stability. For example, the distance the telescopic arm is extended can affect a vehicle moment. The weight of the load and the length of the extended arm can therefore be a basis for vehicle stability. For example, the heavier the load, the less the arm can be extended to maintain vehicle stability. One way to determine the extended length of the telescopic arm is to extend a wire as the telescopic arm is extended.The distance the wire is extended can correlate with a change in the resistance of potentiometers, which rotate when a wire is pulled out and removed from a sensor. The potentiometers may be bolted to a circuit board, and gears may be mounted on the shafts extending from the potentiometers. The gears may rotate when the wire is pulled off a slider as the arm extends. However, during assembly of the potentiometer-based sensor, the gears may move away from the potentiometer's home position, shifting the potentiometer's zero position. In addition, the gears and potentiometers can also allow environmental elements (e.g., water, sand, ice, etc.) access to the electrical components that convert the potentiometer's rotation into a signal representative of a linear distance.This can lead to sensor degradation (e.g., signal loss, inaccurate signal, etc.). Therefore, it may be desirable to develop a sensor capable of determining a linear distance without being affected by gears that may move during sensor assembly. It may also be desirable for the sensor to be less sensitive to environmental factors.

[0003] To solve at least part of the above-mentioned problems, the inventors herein have developed a linear distance measuring system comprising: an airtight chamber having a first coil, a second coil, a third coil, an intermediate cover, and a cover, wherein the intermediate cover has a cylindrical projection configured to receive a slider.

[0004] By enclosing the sensor coils in an airtight chamber formed by an intermediate cover and a cover, which features a cylindrical protrusion for accommodating a slider, the technical result of converting linear motion into a signal with a reduced possibility of signal degradation due to environmental conditions can be achieved. Furthermore, the position of the coil can be detected while the slider is stationary, allowing the position of the slider to be determined after the linear distance measuring system has been disconnected from the power supply and then reconnected.

[0005] The present description can provide several advantages. In particular, this approach can reduce contamination of electrical components due to environmental operating conditions. Furthermore, the approach provides a contactless sensor that may prove more reliable than potentiometer-based sensors. Furthermore, the sensor can be easily mounted without issues related to sensor misalignment.

[0006] It should be understood that the above summary is intended to introduce, in a simplified form, a selection of concepts that are further explained in the detailed description. It is not intended to identify important features of the claimed subject matter, the scope of which is clearly defined by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages noted above or elsewhere in this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows an example vehicle with a linear distance measuring sensor. Fig. 2 shows a schematic representation of the sensor coils. Fig. Figure 3 shows the arrangement of the coils relative to a wire reel for the linear distance measuring sensor. Fig. Figure 4 is a block diagram for the linear distance measuring sensor. Fig. Figure 5 is an exploded view of the linear distance measuring sensor. Fig. 6 is a method for a linear distance measuring device. DETAILED DESCRIPTION

[0007] A method and system for generating a signal proportional to a linear distance traveled by a device are disclosed. In one example, the linear distance may be measured via a cable or cord extended as a device (e.g., a boom or arm) extends. In further examples, the length of the wire or cord may be converted into an angular position of a device (e.g., a bucket, fork, or basket). Fig. Figure 1 shows a non-limiting example of where a linear distance measuring device can be used. Fig. 2 and Fig. 3 shows how the coils (e.g. wire windings) of the sensor are inserted and mounted. Fig. Figure 4 shows a block diagram of example sensors and their relationship to each other. Fig. Figure 5 shows an exploded view of an example sensor. Fig. Finally, Figure 6 shows a flowchart of a method for a linear distance measuring device.

[0008] Fig. 1 shows an illustration of a vehicle 100 including a work implement (e.g., a bucket) powered by a power source that also powers the vehicle's propulsion. In this example, the vehicle 100 is configured as a wheel loader, but in other examples, the vehicle 100 may be configured as a cherry picker, forklift, excavator, backhoe, or other vehicle with one or more attachments. The vehicle 100 may be an off-road vehicle in one example, but on-road vehicles are also contemplated. Industries and corresponding operating environments in which the vehicle 100 may be used include logistics, forestry, mining, agriculture, construction, oil and gas, and the like.

[0009] The vehicle 100 is shown with a telescopic boom 102 that can extend and retract as indicated by arrows 108. The telescopic boom has an outer arm 102a and an inner arm 102b. The inner arm 102b can slide into and out of the outer arm 102a, as indicated by arrows 108. The inner arm 102b can be extended or retracted via a hydraulic cylinder 120 (e.g., an actuator), as indicated by arrows 108. The distance the inner arm 102b is extended can be measured with a linear distance measuring sensor 130 (e.g., a linear displacement transducer (LVDT)). The linear distance measuring sensor 130 includes a wire 132 that extends and retracts with the inner arm 102b. The angle of the telescopic boom relative to the ground can be adjusted via a hydraulic cylinder 104 (e.g., an actuator), as indicated by arrows 106. The telescopic boom 102 also has a bucket 114.A position of the bucket 114 can be adjusted via a hydraulic cylinder 110 (e.g., an actuator), as indicated by arrows 112. The telescopic boom 102 can also include a second outer arm (not shown) and a second inner arm (not shown) configured similarly to the outer arm 102a and the inner arm 102b. The second outer arm and the second inner arm can be arranged parallel to the outer arm 102a and the inner arm 102b, so that loads of the telescopic boom 102 can be distributed between the two outer arms.

[0010] Fig. Figure 2 shows a schematic representation of the coils of the linear distance measuring sensor 130. The linear distance measuring sensor 130 includes an AC power source 202 that is directly electrically connected to a second coil 204 (e.g., an input coil). The second coil 204 generates a magnetic field that can induce a voltage in the first coil 208 (e.g., an output coil) and / or the third coil 210 (e.g., an output coil) via the sliders 206. The slider 206 is composed of a ferromagnetic material so that it can transfer the magnetic flux generated by the second coil 204 to the first coil 208 and the third coil 210, thereby generating voltages across the first coil 208 and the third coil 210. The strength of the magnetic flux transmitted to the first coil 208 and the third coil 210 depends on the position of the slider 206.The first coil 208 is directly electrically coupled to the third coil 210, and the first coil 208 and the third coil 210 are not electrically connected to the second coil 204. A first voltage Es1 is generated across the first coil 208 and a second voltage Es2 is generated across the third coil 210. The output voltage between the first terminal 220 and the second terminal 222 is referred to as Eo and corresponds to the voltage difference Es1-Es2.

[0011] Fig. 3 shows the positions of the coils in the linear distance measuring sensor 130. The linear distance measuring sensor 130 includes a sealed portion 302 and an unsealed portion 303. The sealed portion 302 is airtight and is formed by an intermediate cover and a cover, as shown in Fig. 5. The first coil 208 is located directly adjacent to the second coil 204 such that there are no other coils between the first coil 208 and the second coil 204. The third coil 210 is also located directly adjacent to the second coil 204 such that there are no other coils between the third coil 210 and the second coil 204. The slider 206 can move in the axial direction, as indicated by arrow 320. The threads 312 of a lead screw can enable the rotational motion of the pulley 308 to be converted into linear motion in the axial direction indicated by arrow 320. A sealed electrical connector 304 allows wires to enter the sealed portion 302 without allowing air to enter the sealed portion 302. The unsealed section includes a wire opening through which the wire can enter and exit the unsealed section 303.

[0012] Reference is now made to Fig. 4, which shows a block diagram of a method 400 for generating demanded power for devices of a vehicle. The electrical wires enter the sealed section 302 and terminate at the electrical connector 402. The conductors carry the electrical energy to the direct current-to-direct current (DC / DC) converter 404. The DC / DC converter 404 outputs a regulated output voltage (e.g., 5 VDC) to the LVDT conditioner 406 and a low-dropout regulator 412 (e.g., a voltage regulator). The low-dropout regulator 412 supplies power to the Controller Area Network (CAN) transceiver and the pulse width modulation generator 410.

[0013] The LVDT conditioner 406 supplies an alternating current to the second coil 204 via the electrical connector 408 and receives an output voltage from the first coil 208 and the third coil 210. The LVDT conditioner 406 outputs a signal (e.g., voltage or current) proportional to the position of the slider 206 to the second-order low-pass filter 414. The second-order low-pass filter 414 outputs a low-pass filtered slider position to the microcontroller 416. The microcontroller 416 outputs a digital representation of the position of the slider 206 as a voltage to the CAN transceiver and the pulse width modulation generator 410. The microcontroller 416 includes a non-transitory memory 416a for storing executable instructions, inputs 416b (e.g., digital and analog inputs), and outputs 416c (digital and analog outputs).The CAN (Controller Area Network) transceiver and the pulse width modulation generator 410 output a signal representative of the position of the slider to external devices via the electrical connector 402.

[0014] Fig. 5 shows an exploded view of the linear distance measuring sensor 130. Fig. 5 shows perspective sections of a linear distance measuring sensor on the left side of Fig. 5 and perspective sections of a linear distance measuring sensor on the right side of Fig. 5.

[0015] The linear distance measuring sensor includes a base 520, an intermediate cover 510, and a cover 502. The cover 502 can be attached to the intermediate cover 510 and the base 520 with four fasteners (e.g., screws) (not shown). The cover 502 includes an electrical connector 304 that enables the transmission of signals and electrical power between external devices (not shown) and the linear distance measuring sensor. The gasket 506 can form an airtight seal between the cover 502 and the intermediate cover 510. The circuit board 508 is also contained within the airtight chamber 570 formed between the cover 502 and the intermediate cover 510 when the cover 502 engages the intermediate cover 510 to form an airtight chamber 570. The circuit board 508 includes the circuit boards shown in the block diagram of Fig. 4. The first coil 208, the second coil 204, and the third coil 210 are also located in the airtight chamber 570.

[0016] The intermediate cover 501 includes a protrusion 575 that extends through the centers of the first coil 208, the second coil 204, and the third coil 210, indicated by the centerline 565. Thus, the protrusion 575 serves as a support for the first coil 208, the second coil 204, and the third coil 210. The intermediate cover is blow-molded over the bushing 514. The bushing 514 includes a slot 550 that prevents the slider 206 from rotating. However, the slot 550 allows the slider 206 to move axially, as indicated by arrow 320. The cover 502 and the intermediate cover 510 are formed from a non-ferrous material (e.g., a polymer such as plastic).

[0017] A return spring 524 is located between the base 520 and the pulley 308. The pulley 308 is clamped between the base 520 and the intermediate cover 510 so that its axial play is zero. The return spring 524 has an inner end connected to the base 520 and an outer end connected to the pulley 308. The return spring 524 generates a force (e.g., 0.5 Newton meters) to wind the wire 530 around the pulley 308. The wire can be unwound when the pulley 308 rotates counterclockwise with respect to the base 520 and the intermediate cover 510. The cylindrical bushing 522 is attached to the base 520 and provides rotational and axial guidance of the pulley 308. The lead screw 526 is attached to the pulley 308 and rotates with the pulley 308. The lead screw 526 has a thread 554 that engages the thread 552 of the slider 206.As the pulley 308 rotates, the threads 554 of the lead screw 526 exert a force on the threads 552 of the slider 206, causing the slider 206 to move axially, as indicated by arrow 320. The milled surface 560 fits into the slot 550 to form a prismatic connection, thereby preventing the slider 206 from rotating when the pulley 308 rotates. The dimensions of . Fig. 5 are shown approximately to scale.

[0018] This is what the system of Fig. 1-5 proposes a linear distance measuring system comprising: an airtight chamber having a first coil, a second coil, a third coil, an intermediate cover, and a cover, wherein the intermediate cover has a cylindrical projection configured to receive a slider. In a first example, the linear distance measuring system further comprises electrical components for generating an alternating current signal and electrical components that generate a signal proportional to a position of the slider. The signal may, for example, be linearly or non-linearly proportional to the position of the slider. Furthermore, the relationship may be an affine relationship. In a second example, which may include the first example, the linear distance measuring system includes the cylindrical projection passing through a center of the first coil, a center of the second coil, and a center of the third coil.In a third example, which may include both the first and second examples, the linear distance measuring system comprises a first coil directly adjacent to the second coil. In a fourth example, which may include one or more of the first to third examples, the linear distance measuring system comprises a second coil directly adjacent to the third coil. In a fifth example, which may include one or more of the first to fourth examples, the linear distance measuring system comprises electrical components for generating the alternating current that are electrically connected to the second coil. In a sixth example, which may include one or more of the first to fifth examples, the linear distance measuring system comprises electrical components for generating the signal that are electrically connected to the first coil and the third coil.In a seventh example, which may include one or more of the first to sixth examples, the linear distance measuring system includes the cover and the intermediate cover being composed of a polymer. In an eighth example, which may include one or more of the first to seventh examples, the linear distance measuring system includes the intermediate cover being molded over a circular bushing, and the circular bushing having a through-hole aligned with a center of the cylindrical protrusion. In a ninth example, which may include one or more of the first to eighth examples, the linear distance measuring system includes a circular bushing having a counterbore. In a tenth example, which may include one or more of the first to ninth examples, the linear distance measuring system further includes an electrical connector included in the cover.

[0019] The system of Fig. 1-5 also provides a non-contact linear displacement transducer (LVDT) sensor system comprising: a housing containing: a sealed chamber containing a plurality of solenoid coils connected to a circuit board; and an unsealed mechanical chamber containing a coil spring, a wire reel, and a ferromagnetic slider extending into a cavity side of a boss extending into the sealed chamber, the slider being axially moved by rotation of the wire reel. In a first example, the non-contact LVDT sensor system includes a plurality of solenoid coils including a first output coil, a second input coil, and a third output coil. In a second example, which may include the first example, the non-contact LVDT sensor system further includes a lead screw connected to the wire reel and the ferromagnetic slider.In a third example, which may include one or both of the first and second examples, the non-contact LVDT sensor system includes the sealed chamber formed via an intermediate cover and a cover. In a fourth example, which may include one or more of the first to third examples, the non-contact LVDT sensor system includes an intermediate cover molded over a bushing.

[0020] Fig. 6 shows a method for a linear distance measuring device. The method of Fig. 6 can be performed by a human or a machine on a vehicle assembly line. The process of Fig. 6 describes actions that can be performed in the physical world by a human or a machine. At least part of the processes for Fig. The actions described in section 6 can be performed by a controller that executes instructions stored in the controller's non-transitory memory. The controller can operate the hardware and actuators described here to perform the actions in the physical world.

[0021] In 602, three coils (e.g., one input coil and two output coils) and the electronics (e.g., control, LDO, DC / DC, LVDT conditions, etc., as in Fig. 4) is installed in a hermetically sealed chamber of a linear distance measuring sensor. The linear distance sensor is formed by a cover and an intermediate cover, as shown in Fig. 5. The electronics can be encapsulated in an epoxy support structure or as a printed circuit board. The process 600 proceeds to 604.

[0022] At 604, in method 600, a slider, a pulley, a return spring, a lead screw, a circular bushing, and a wire are inserted into an unsealed chamber of the linear distance measuring sensor. The unsealed chamber is formed by a bottom and an intermediate cover, as shown in Fig. 5. Method 600 continues with 606.

[0023] At 606, method 600 moves the slider in an axial direction relative to the linear distance measurement sensor in response to the rotational movement of a pulley. The pulley is rotated by winding or unwinding wire from the pulley. The change in direction from rotary to linear motion is accomplished via a lead screw and the threads of a slider, as shown in Fig. 5. Method 600 continues with 608.

[0024] At 608, the method 600 converts a voltage supplied by two coils (e.g., the first and third coils as shown in Fig. 2) into a signal indicative of the linear movement of the slider. The signal can be a digital signal or an analog signal. Since the slider is coupled to the wire being wound off or onto the slider, the signal is proportional to the length of wire being wound off the reel or onto the pulley. Method 600 exits.

[0025] In this way, the linear movement of a device can be tracked via the movement of a wire, and a signal can be generated from the movement of the wire. The sensor operates on the principle of induction, meaning it is a non-contact sensor, allowing a large portion of the sensor to be isolated from the ambient conditions.

[0026] This is how the procedure of Fig.6 proposes a method for generating a signal representative of linear movement, comprising the steps of: converting rotation of a pulley into linear movement of a slider in a cavity of an intermediate cover, the intermediate cover and a cover forming an airtight chamber; and generating a signal dependent on a position of the slider. In a first example, the method comprises generating the signal via the output of a first coil and a third coil while supplying a second coil with an alternating current. In a second example, which may include the first example, the method includes a projection of the intermediate cover passing through the first coil, the second coil, and the third coil.In a third example, which may include one or both of the first and second methods, the method includes disposing the second coil between the first coil and the third coil.

[0027] It should be noted that the example control and estimation routines included herein can be used with sensor configurations. At least a portion of the control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and executed by the control system, including the controller, in combination with the various sensors, actuators, and other transmission and / or vehicle hardware. Furthermore, portions of the methods may be physical actions performed in the real world to change the state of a device. Thus, at least some of the described actions, operations, and / or functions may graphically represent code to be programmed into the non-transitory memory of the computer-readable storage medium in the vehicle and / or transmission control system.The specific routines described herein may represent one or more arbitrary processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Thus, the various actions, operations, and / or functions illustrated may be performed in the order presented, in parallel, or in some cases, without them. Accordingly, the order of processing is not required to achieve the features and advantages of the examples described herein, but is provided for convenience of illustration and description. One or more of the illustrated actions, operations, and / or functions may be performed repeatedly depending on the strategy used. One or more of the method steps described herein may also be omitted if desired.

[0028] Although various embodiments have been described above, it is to be understood that these have been presented by way of example and not by way of limitation. It will be apparent to those skilled in the art that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter. The embodiments described above are, therefore, to be considered in all respects as illustrative and not restrictive. The configurations and routines presented herein are exemplary, and these specific examples are not to be considered limiting, as numerous variations are possible. For example, the technology described above may be applied to various types of machines.The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, as well as other features, functions and / or properties disclosed herein.

[0029] The following claims particularly point out certain combinations and sub-combinations that are considered novel and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims are to be understood as encompassing inclusion of one or more such elements, not as requiring or excluding two or more such elements. Further combinations and sub-combinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by presenting new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope than the original claims, are also considered to be included within the subject matter of the present disclosure.

Claims

[1] Linear distance measuring system, comprising: an airtight chamber having a first coil, a second coil, a third coil, an intermediate cover and a cover, wherein the intermediate cover has a cylindrical projection configured to receive a slider. [2] The linear distance measuring system of claim 1, further comprising electrical components for generating an alternating current signal and electrical components that generate a signal proportional to a position of the slider. [3] A linear distance measuring system according to claim 2, wherein the cylindrical projection passes through a center of the first coil, a center of the second coil and a center of the third coil. [4] A linear distance measuring system according to claim 3, wherein the first coil is directly adjacent to the second coil. [5] Linear distance measuring system according to claim 4, wherein the second coil is directly adjacent to the third coil. [6] A linear distance measuring system according to claim 5, wherein the electrical components for generating the alternating current signal are electrically coupled to the second coil. [7] The linear distance measuring system of claim 6, wherein the electrical components for generating the signal are electrically coupled to the first coil and the third coil. [8] Linear distance measuring system according to one of the preceding claims, wherein the cover and the intermediate cover are composed of a polymer. [9] A linear distance measuring system according to any one of the preceding claims, wherein the intermediate cover is formed over a circular bushing, and the circular bushing has a through hole aligned with a center of the cylindrical projection. [10] The linear distance measuring system of claim 9, wherein the circular bushing further includes a counterbore, and further comprising an electrical connector contained in the cover. [11] Non-contact linear displacement sensor system, comprising: a housing that includes: a sealed chamber containing a plurality of magnetic coils connected to a circuit board; and an unsealed mechanical chamber containing a coil spring, a wire reel, and a ferromagnetic slider extending into a cavity side of a projection extending into the sealed chamber, the ferromagnetic slider being moved axially by rotation of the wire reel. [12] The non-contact linear displacement sensor system of claim 11, wherein the plurality of magnetic coils comprise a first output coil, a second input coil, and a third output coil, further comprising a lead screw coupled to the wire reel and the ferromagnetic slider, wherein the sealed chamber is formed via an intermediate cover and a cover, and wherein the intermediate cover is formed via a bushing.

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