This application is a nonprovisional application under 37 CFR 1.53(b) and is submitted with an accompanying non-publication request in accordance with 35 U.S.C. § 122(b). Accordingly, the subject matter of this application is to be maintained in secrecy until and unless Applicant allows a patent to issue based on this application.
The present invention primarily pertains to control systems and methods for boom lifts, cherry pickers, and other similar devices; more particularly it pertains to systems and methods for allowing Cartesian steering controls for said devices.
Most boom lifts or other similar vehicles use controls that operate the various components of the lift individually. In these systems, simple Cartesian operations such as lifting the operator platform vertically or horizontally can involve multiple control operations such as extending the lower telescoping boom assemblies, while retracting the upper telescoping boom assemblies, which also changes the angles of said upper and lower boom assemblies. Simple Cartesian operations present a surprisingly complex array of challenges for even skilled and experienced operators to perform with standard control systems.
To overcome this problem the industry has developed Cartesian control systems to provide easy, accurate, and reliable changes in the operator platform's Cartesian location. In such control systems, if the operator wants to move the operator platform up, down, left, or right, all that is needed is a simple button press and the control system calculates and coordinates the proper control actions of the various telescoping assemblies and angles. However, these current systems require the installation and calibration of expensive sensors to measure the overall and current length of the telescoping boom assemblies, sensors to measure the rate of speed of their extension or retraction, sensors to detect the amount of hydraulic pressure to the assemblies' control systems, sensors to monitor the angles of the current assemblies, and other similar sensors. The addition of such sensors and their maintenance and calibration adds significantly to the cost of boom lift and other similar vehicles presenting an obstacle to their adoption. Moreover, because of the need for recurring calibration of such sensors, and the distinct possibility of errors occurring in the calibration process, the reliability of commonly used sensors is questionable.
Many other problems, obstacles, limitations and challenges of the prior art will be evident to those skilled in the art, particularly in light of the prior art.
The present invention provides improved control systems and methods for boom lifts, cherry pickers, and other similar devices; more particularly it pertains to systems and methods for allowing Cartesian steering controls for said devices. While typical control systems include multiple controls for extending and retracting the lower and upper telescoping boom assemblies as well as separate controls to change the angles of said upper and lower boom assemblies, the present invention retains such functionality and improves upon the basic control system by incorporating a Cartesian or equivalent adjustment control into the operator control panel. The telescoping boom assemblies preferably utilize linear actuators for extension and retraction of the boom assembly. For implementing adjustments to the angle of the boom assembly, preferred embodiments incorporate rotary actuators.
Presently preferred embodiments of the present invention, which will be described subsequently in greater detail, generally comprise an accelerometer and gyroscope located on or near the operator platform and which provide data to an electronic controller. Preferred embodiments improve overall reliability of its ability to accurately sense the current positions of the boom lift assembly, in part by combining rotary sensors with a solid state accelerometer and/or a solid state gyroscope. Solid state sensors usually do not require recalibration as often to maintain their accuracy. This is in contrast to standard sensors which could be expected to require recalibration more frequently due to their design and method of operation. The electronic controller uses the inputted data to calculate the Cartesian location of the operator platform and its movement, using an algorithm explained in more detail below. The algorithm constantly refines its estimates multiple times per second.
The apparatus and method for the Cartesian control of the operator platform as described in the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus that has many advantages and novel features which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art, either alone or in any obvious combination thereof.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following descriptions or illustrated in the drawings. The invention is capable of many other embodiments and of being practiced and carried out in numerous other ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.
Other objects, features and advantages of the present invention will become evident to the reader and it is intended that these objects, features, and advantages are within the scope of the present invention.
To the accomplishment of all the above and related objectives, it should be recognized that this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specifics illustrated or described.
Reference is made first to
Reference is made to
In Step 104, the electronic controller 80 runs the operator platform control algorithm 70. The operator platform control algorithm 70 is described in more detail below. The electronic controller 80 and its operator platform control algorithm 70 obtain a continual signal from the gyroscopic sensor 51 and accelerometer 52 containing the actual sensed conditions (Step 109). The algorithm 70 uses the actual sensed conditions to calculate an appropriate control signal to achieve the desired action which is then sent to the appropriate controller in Step 105. The electronic controller calculates an anticipated sensed conditions value for the operator platform control algorithm 70 in Step 106. In Step 107, if the anticipated sensed conditions value calculated in Step 106 does not match the actual sensed conditions then the system returns to Step 104. If the value does match, then the system moves to Step 108, wherein the electronic controller determines if the desired action has been completed. If it has not then the system returns to Step 104; if it has then the system returns to Step 101.
The operator platform control algorithm 70 continually refines its estimates of the anticipated sensed conditions value using the data from the actual sensed conditions along with its previous estimates of the anticipated sensed conditions. It should be understood, though, that the sequence and detail of
Electronic Controller
The electronic controller 80 uses one or more presently available computing devices which contain a processor 56, a memory unit 53, one or more input means 55, and one or more output means 54. One example of a controller which is suitable to be programmed for embodiments of the present invention as described herein is any of the HFX series of programmable controllers commercialized by Eaton Corporation [www.eaton.com]. Such controllers incorporate a processor and a memory unit, as well as having capabilities for receiving inputs and for generating outputs. The electronic controller 80 preferably stores part, or all, of the operator platform control algorithm 70. The electronic controller 80 receives information on the sensed conditions and calculates the desired angle(s) and length(s) according to the operator platform control algorithm 70. The electronic controller 80 then uses its control signal generator 81 to communicate a corresponding angle and/or length command to the appropriate rotary joints (61, 62, 63, 64), each of which serves as a controller for adjusting the angular position of the corresponding telescoping assembly. The rotary joints 61, 62, 63, 64 use commercially available or predictable equipment that receives the angle and/or length control signal from control signal generator 81 either by wire or wirelessly and sets or changes the assembly angle and/or length (θ1, θ2, θ3, θ4, L1, L2) to the commanded angle and/or length. Control signal generator 81 sends electrical drive signals to hydraulic solenoids to control flow of hydraulic fluid for operating upper and lower telescoping assemblies 20, 30. These signals are based on current, such signals being variable and proportional. For instance, a zero current value indicates no hydraulic fluid flow. A positive current value will result in flow in one direction, and a negative current value will result in flow in the opposite direction.
Platform Location Algorithm
Platform 50 includes sensors such as gyroscopic sensor 51 and accelerometer 52. In some embodiments, the sensors on platform 50 are made from the components of a Zero Off® module commercially available from Applicant, Enovation Controls, LLC, although the GPS functionality of such modules may be removed as unnecessary for functionality of the present invention. In other embodiments, the sensors may be mounted together on a circuit board. For determining the location of platform 50, rotary joint 61 and/or 62 should be actuated or moved below the extension angle.
For example, when the rotational position of rotary joint 62 moves, if the extension of telescoping assembly 30 is relatively short, the accelerations measurable at platform 50 are small as compared to a situation when telescoping assembly 30 is fully extended, wherein the accelerations measurable at platform 50 would be much larger. For instance, when the operator commands platform 50 to move upward, telescoping assembly 30 will extend upward. However, when translating platform 50 in a vertical direction, telescoping assembly 30 will also tilt backward while platform 50 is translated upward. It is when rotary joint 62 moves in this rotational fashion, the length of extension of telescoping assembly 30 can be estimated based on the acceleration measurement made at platform 50.
The following represents the mathematical relationships related to platform location algorithm 90:
A 3-axis accelerometer 52 and a 3-axis gyroscopic sensor 51 are positioned on platform 50. Let θ1, θ2, θ3, θ4 be measured values using rotational position sensors on each rotary joint. L1 is fixed and known. L2 is not measured but will be estimated:
2=actual length of L2 (unknown)
{tilde over (L)}2=estimate estimated length of L2
2d=desired length of L2
If lift vehicle 10 is stationary, then a point “B” on platform 50 can be described relative to a point “O” at the origin of the XYZ axes as shown in
B=fP(θ1, θ2, θ3, θ4, L1, L2)
B=fV(θ1, {dot over (θ)}1, θ2, {dot over (θ)}2, θ3, {dot over (θ)}3, θ4, {dot over (θ)}4, L1,
ĀB=fA(θ1, {dot over (θ)}1, {umlaut over (θ)}1, θ2, {dot over (θ)}2, {umlaut over (θ)}2, θ3, {dot over (θ)}3, {umlaut over (θ)}3, θ4, {dot over (θ)}4, {umlaut over (θ)}4, L1,
{tilde over (P)}B=fP(θ1, θ2, θ3, θ4, L1, {tilde over (L)}2)
{tilde over (V)}B=fV( . . . , {tilde over (L)}2, {dot over ({tilde over (L)})}2)
ÃB=fA( . . . {tilde over (L)}2, {dot over ({tilde over (L)})}2, {umlaut over ({tilde over (L)})}2)
Where the “dot” notation means:
{dot over (x)}=(d/dt)x
{umlaut over (x)}=(d2/dt2)x; where “t” equals time
And:
{tilde over (P)}B, {tilde over (V)}B, ÃB=estimated position, velocity, and acceleration of point B—both translational and rotational.
The only unknown in {tilde over (P)}B is {tilde over (L)}2.
An algorithm that can continuously improve the accuracy of the estimated length {tilde over (L)}2 is called an “observer” by those of ordinary skill in the art of control theory. One embodiment of such an algorithm can be written as:
{tilde over (L)}2new={tilde over (L)}2old+[{dot over ({tilde over (L)})}2old+KVMV(
where Δt=time step between observer digital updates; KV=a “gain” value which can speed up or slow down how quickly estimates are improved; MV=a “mapping” matrix which inverts the kinematics of fV( . . . ).
Clearly, when (
Operator Platform Control Algorithm
An operator platform control algorithm 70 is preferably implemented in electronic controller 80. The operator platform control algorithm 70 may include any common or advanced control loop transfer function including, but not limited to, series, parallel, ideal, interacting, noninteracting, analog, classical, and Laplace types. In preferred embodiments, the control loop transfer function actuates hydraulic control valves that regulate the flow of hydraulic fluid to the various actuators. When an operator moves joystick 302 and/or 304 (as shown in
The operator platform control algorithm 70 calculates the desired assembly angle and/or length (θ1, θ2, θ3, θ4, L1, L2) based on input information from an appropriate one or more of the sensors (gyroscopic sensor 51 and accelerometer 52) that are available. The operator platform control algorithm 70 receives input information from the device systems and controls that are equipped with such sensors. As used herein, the term sensor is not limited to a single device detecting and reporting a single condition. A sensor may be one or more devices detecting and reporting one or more conditions. As used in the preferred embodiment the gyroscopic sensor 51 is a solid state sensor which detects the rotational motion and magnitude of the operator platform. The accelerometer sensor 52 is preferably a solid state sensor which detects the linear motion and amplitude of the operator platform.
Based on the input information from one or more sensors, the operator platform control algorithm 70 calculates angles and/or lengths for one or both telescoping assemblies 20 and 30. For each telescoping assembly 20 and 30 it is controlling, the operator platform control algorithm 70 calculates an angle and/or length (θ1, θ2, θ3, θ4, L1, L2) and a corresponding angle and/or length command to achieve as much. The operator platform control algorithm 70 calculates the desired angle and/or length (θ1, θ2, θ3, θ4, L1, L2) based on the sensed conditions. However, because of the inherent limits of the control systems, the desired angle and/or length (θ1, θ2, θ3, θ4, L2) may not be achievable, either instantaneously or at all. An angle and/or length rate limiting function may also be implemented in the electronic controller 80, in rotary joints 61, 62, 63, 64 by some other means, or may not be necessary based on the type of the devices' pre-existing controls. When the control system relies on the algorithm to limit the rate of change of the angle and/or length (θ1, θ2, θ3, θ4, L1, L2), the algorithm computes intermediate commanded angles and/or lengths to achieve a desired angle and/or length.
The electronic controller 80 preferably includes a comparator function with which the operator platform control algorithm 70 compares the desired angle and/or length (θ1, θ2, θ3, θ4, L1, L2) with the current angle and/or length (θ1, θ2, θ3, θ4, L1, L2) as detected by gyroscopic sensor 51 and/or accelerometer 52 and computed by the platform location algorithm 90. The algorithm 70 produces a series of intermediate commanded angles and/or lengths (θ1, θ2, θ3, θ4, L1, L2) that achieve the desired angle and/or length (θ1, θ2, θ3, θ4, L1, L2) without exceeding the control system's maximum permissible rate of change of angle and/or length. Further, the operator platform control algorithm 70 is adapted to limit the commanded angle to the vehicle control system's mechanical limits. The operator platform control algorithm 70 also preferably contains a smoothing function to avoid rapid changes in angle and/or length commands. The smoothing function compensates for noise in sensors or controls and for rapid fluctuations in sensed conditions. Such smoothing function is preferably a standard low-pass filter, the performance of which will be understood by those of ordinary skill in the art.
The operator platform control algorithm 70 also includes internal limitations for other operating and safety considerations. For example, regardless of sensed conditions, the operator platform control algorithm 70 never commands an angle and/or length in excess of the mechanical or safety limits of the telescoping assemblies 20 and 30. In case of certain sensor failures, the electronic controller informs the operator a failure has occurred and commands the telescoping assemblies 20 and 30 to a safe angle and/or length with a safety control signal. In case of electronic controller failure, a fail-safe operates to disable Cartesian movement and allow the vehicle's manual steering system to resume unaided control of the telescoping assemblies 20 and 30.
Turning now to
Joystick 304, shown on the left side of control panel 300, operates to move operator platform 50 in the “z” plane of Cartesian movement. In other words, as indicated by arrows 314, 316, joystick 304 implements vertical movement (up and down) of operator platform 50. With respect to joystick 302, movement can be implemented in the “x-y” plane of Cartesian movement. In other words, as indicated by arrows 306, 308, joystick 302 can implement movement of operator platform 50 in a forward and reverse direction, respectively. Furthermore, if joystick 302 is moved in accordance with arrows 310, 312, operator platform may be moved in a lateral or a left or right direction. Although not shown in
Although
The system and methods of the present invention therefore provide a control mechanism whereby the operator is able to operate the operator platform 50 in Cartesian space, requiring only the indication of which direction the operator desires the operator platform 50 to travel in. Although the present invention has been described in conjunction with particular preferred structures, and in conjunction with generalized, preferred methods of operation for these structures, those skilled in the art will recognize many other modifications to the structures and methodology that still fall within the scope of the invention. The specific electrical and electronic functionality associated with components like the electronic controller 80, the gyroscopic sensor 51, and the accelerometer 52 may, for example, be implemented in any of a number of different ways using a variety of different electronic and/or mechanical components. As long as the electronic controller 80 is appropriately programmed or electronically structured to receive the signals or electrical characteristics from these electronic devices and sensors, then any of a number of different electrical components may be used for these two inventive elements. In some cases, electrical or electronic devices may be used in place of the mechanical linkages described herein. Hard wired connections can also be replaced with wireless connections to the extent not clearly forbidden by the properly construed claims. Certainly, modifications as to geometry, shape, and size could and likely would vary according to the size and placement of the existing control systems associated with a particular device.
In all respects, it should also be understood that the drawings and detailed description herein are to be regarded in an illustrative rather than a restrictive manner, and are not intended to limit the invention to the particular forms and examples disclosed. Rather, the invention includes all embodiments and methods within the scope and spirit of the invention as claimed, as the claims may be amended, replaced or otherwise modified during the course of related prosecution. Any current, amended, or added claims should be interpreted to embrace all further modifications, changes, rearrangements, substitutions, alternatives, design choices, and embodiments that may be evident to those of skill in the art, whether now known or later discovered. In any case, all substantially equivalent systems, articles, and methods should be considered within the scope of the invention and absent express indication otherwise, all structural or functional equivalents are anticipated to remain within the spirit and scope of the present inventive system and method.
The present application is a continuation-in-part of prior filed co-pending U.S. Non-Provisional patent application Ser. No. 13/465,683 filed May 7, 2012, and also claims the benefit of its prior filed priority document, namely U.S. Provisional Application, Ser. No. 61/482,943 filed May 5, 2011. By this reference, the full disclosures, including the claims and drawings, of U.S. Non-Provisional application Ser. No. 13/465,683 and U.S. Provisional Application, Ser. No. 61/482,943 are incorporated herein as though now set forth in their entirety.
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Parent | 13465683 | May 2012 | US |
Child | 15001179 | US |