US20160298314A1

US20160298314A1 - System and method for machine control

Info

Publication number: US20160298314A1
Application number: US15/188,591
Authority: US
Inventors: Nathan R. Fogg; Darren M. Schambach; Andrew N. Schifferer; Eric W. Cler; Aaron R. Shatters; Scott A. McGregor
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2016-06-21
Filing date: 2016-06-21
Publication date: 2016-10-13

Abstract

A system for controlling operations of a machine is provided. A first sensor module generates a signal indicative of an operator command and a second sensor module is configured to generate a signal indicative of a current loading ratio associated with a load arm assembly of the machine. A control module is communicably coupled to the first sensor module and the second sensor module to receive a signal indicative of a current operating mode of the machine, and further to receive the signal indicative of the operator command and the signal indicative of the current loading ratio associated with the load arm assembly of the machine. Further, the control module compares the current loading ratio with a pre-determined load rating of the machine, and selectively limits an action associated with the operator command based on the comparison and the current operating mode of the machine.

Description

TECHNICAL FIELD

The present disclosure relates to controlling an operation of a machine.

BACKGROUND

Machines are employed for a variety of tasks in construction, mining and/or other applications. These machines include, but are not limited to, skid steer loaders, wheel loaders, backhoe loaders, forklifts, and compact track loaders. For example, the wheel loader includes a work tool that may be raised and lowered based on inputs from an operator. The work tool is connected to a stick and boom assembly for loading and unloading materials, such as dirt, sand, or gravel and moving the material from one place to another.
During operations, the machine may experience dynamic events. The dynamic events may occur when the machine is operated beyond its operating capability or conditions where the machine is subjected to rapid change in material loads or sudden movement. Conventional techniques for improving stability of the machine are based on a static center-of-gravity (CG) analysis. However, such techniques may not efficiently stabilize the machine, when the loaded material is particularly heavy. As a consequence, there are chances of strain or stress on various components, such as a frame of the machine. As a result, the machine suffers from increased down-time and maintenance costs.
U.S. Published Application Number 2010/0204891 describes a control system for a vehicle having a loader arm, such as a skid steer loader, telescopic handler, wheel loader, backhoe loader or forklift. The vehicle may include an electronic control system capable of electronically monitoring the skid steer loader's load, the height of that load, and of responsively derating or reducing the drive system's response to operator commands. The electronic control system combines these sensor signals and, by dynamically and continuously calculating if the drive system needs derating and a magnitude by which this control may need to be exercised. The electronic control system generates a signal to limit the acceleration of the vehicle to less than the dynamically calculated acceleration necessary to cause the dynamic center of gravity of the combined vehicle and load to extend exterior of an edge of the stability polygon for the vehicle.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, a system for controlling operations of a machine is provided. The system includes a first sensor module, a second sensor module, and a control module. The first sensor module is configured to generate a signal indicative of an operator command. The second sensor module is configured to generate a signal indicative of a current loading ratio associated with a load arm assembly of the machine. The control module is communicably coupled to the first sensor module and the second sensor module. The control module is configured to receive a signal indicative of a current operating mode of the machine. The control module is configured to receive the signal indicative of the operator command and the signal indicative of the current loading ratio associated with the load arm assembly of the machine. The control module is configured to compare the current loading ratio with a pre-determined load rating of the machine. The control module is configured to selectively limit an action associated with the operator command based on the comparison and the current operating mode of the machine.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary machine, in accordance with the concepts of the present disclosure; and

FIG. 2 is a block diagram of a system for controlling an operation of the machine.

DETAILED DESCRIPTION

Referring to FIG. 1, an exemplary machine 10 is illustrated. The machine 10 shown in FIG. 1 is a wheel loader. The machine 10 is used for loading and unloading of various types of materials, such as stones, marble in block form and also earthen material. The machine 10 includes a load arm assembly 12 that further includes a work tool 14 utilized for carrying the materials. The work tool 14 maybe a bucket, a fork, a material handling arm, or any other handling equipments. The load arm assembly 12 is mounted to a frame 16 of the machine 10, and further includes booms 18 coupled to the work tool 14. The booms 18 are used to lift the work tool 14 to carry out various operations. The machine 10 further includes a hydraulic cylinder 20 coupled to a bellcrank 22. The bellcrank 22 is further coupled to the booms 18 using a connecting member 24 and a linkage 26. The bellcrank 22 is also coupled to a bellcrank bar 28, disposed between the booms 18, via a pivot joint (not shown). The bellcrank bar 28 couples the work tool 14 to the bellcrank 22, thus enabling an orientation of the work tool 14 to be varied by retracting and expanding the hydraulic cylinder 20. Alternatively, structure of the load arm assembly 12 of the machine 10 may vary from one machine to another, and therefore, number of hydraulic cylinders and other components may vary depending on type of the machine 10.
The machine 10 further includes an operator cabin 30 and a seat 32. An operator sits on the seat 32 in the operator cabin 30 for controlling various operations of the machine 10 such as loading and unloading of various types of materials. Further, the machine 10 includes an engine 34 and a number of wheels 36. The engine 34 provides power to the machine 10 for carrying out various operations. The operator controls and monitors operating parameters of the machine 10 via input and/or output modules. The input and/or output modules may include a display device, a camera, a steering wheel, a speaker, a joystick or other input and/or output devices. The machine 10 is used for various operations such as, but not limited to, grading of land, or loading, or transportation of materials, among others. The machine 10 may be any other wheeled machine including, but not limited to, a track loader, a wheel dozer, an excavator, or any other suitable machine, without departing from the scope of the disclosure.
Referring to FIG. 2, a system 38 for controlling operations of the machine 10 is illustrated. The system 38 includes a first sensor module 40 and a second sensor module 42. The first sensor module 40 is configured to generate a signal indicative of an operator command. In an exemplary embodiment, the first sensor module 40 may be a joystick position sensor that uses a rotary potentiometer to produce an electrical signal in response to a pivotal position of a control lever as operated by the operator. When the operator moves the control lever, the electrical signal is generated that is indicative of the operator command.
In one example, the operator command is associated with operations performed on or using the load arm assembly 12 of the machine 10. These operations are related to loading and unloading of the material from the machine 10. Examples of the operator command may include, but are not limited to, a lift command and a tilt command. The lift command is used to raise or lower the work tool 14. The tilt command is used for tilting the work tool 14 for the racking/dumping operations. The first sensor module 40 may be an eddy-current sensor, a hall-effect sensor or a proximity sensor, among others. Also, the first sensor module 40 may include various sensors, such as sensors located on a steering, a joystick, or any other components of the machine 10. In another example, the operator command is associated with other activities of the machine 10, such as speed, heading, etc.
The second sensor module 42 is configured to generate a signal indicative of a current loading ratio associated with the load arm assembly 12 of the machine 10. The loading ratio is indicative of a current load present on the machine 10 with respect to a total load that the machine 10 is capable of handling. The loading ratio is calculated from operating values received from a head end (not shown) and a rod end (not shown) of the hydraulic cylinder 20. Alternatively, the loading ratio may also he calculated using strain gauges, other instruments or any other mechanism without departing from the disclosure. The second sensor module 42 may include strain gauges, pressure sensors, or any other sensor. Also, the second sensor module 42 may include various other sensors, such as sensors located on the hydraulic cylinder 20, the load arm assembly 12, or any other components within the machine 10.
Referring to FIG. 2, a control module 44 is communicably coupled with the first sensor module 40 and the second sensor module 42. The control module 44 is configured to receive a signal indicative of a current operating mode of the machine 10. The operating modes may be a “dig state” or any other operating mode hereinafter referred as a “non-dig state”. The term “dig state” refers to a state in which the machine 10 is performing a digging operation. Alternatively, the term “non-dig state” refers to a state in which the machine 10 is performing operations other than digging operation, such as material handling and transportation, etc. The signal indicative of the current operating mode may be received from a third sensor module (not shown). Alternatively, the signal indicative of the current operating mode may he input by the operator.
The control module 44 receives the signal indicative of the operator command from the first sensor module 40. Further, the control module 44 receives the signal indicative of the current loading ratio associated with the load arm assembly 12 of the machine 10. The control module 44 is communicably coupled with a database 46 that stores a pre-determined load rating of the machine 10. The control module 44 compares the current loading ratio with the pre-determined load rating.
The control module 44 may further limit an action associated with the operator commands based on the comparison and the current operating mode of the machine 10. Based on the comparison between the current loading ratio with the pre-determined load rating, the control module 44 limits the action associated with the operator command, such as the lift command and the tilt command. As an example, the control module 44 may variably limit an action associated with the operator command, for example the action may include movements of the load aim assembly 12 of the machine 10. The control module 44 may control the operating parameters of the machine 10 within the permissible range. For example, if the current loading ratio is less than the pre-determined load rating, then the command and parameters associated with the lift command are unaltered. Else, if the current loading ratio is more than the pre-determined load rating, then the control module 44 is configured to limit the command and parameters associated with the lift command.
As an example, a low pass filter (LPF) or any other logic may he used for limiting the action of the operator command. The control module 44 is configured to limit a magnitude and/or rate of application of the action of the operator command. For example, the control module 44 may be configured to change a pressure of the hydraulic cylinder 20 from 100% to 60% to limit an action associated with the lift command of the work tool 14. Further, the control module 44 may also be configured to change the rate of application by increasing a time for executing the command from 0.25 seconds to 4.0 seconds for limiting the action associated with the lift command of the work tool 14. Alternatively, the control module 44 may also he configured to change the magnitude as well as rate of application in other possible combinations to limit the action associated with the lift command.
In other embodiments, the signals from the first sensor module 40 and the second sensor module 42 may be received or interpreted by the control module 44 only when the control module 44 has determined that the machine 10 is operating in the non-dig state. In another embodiment, the signals from the first sensor module 40 and the second sensor module 42 may be continuously received, but the comparison of the loading ratio with the pre-determined load rating may take place after the control module 44 has determined that the machine 10 is operating in the non-dig state.
The database 46 includes a memory for storing the pre-determined load rating. The pre-determined load rating may be calculated on the basis of historical data and defines a range of operating the machine 10 within permissible limit. The pre-determined load rating may contain readings of pre-estimated load values during various operating conditions associated with the machine 10. The database 46 includes look-up tables for storing the pre-determined load rating of the machine 10. The database 46 may be any conventional or non-conventional database known in the art. In one embodiment, the database 46 may be extrinsic to the machine 10 and located at a remote location away from the machine 10. Alternatively, the database 46 may be intrinsic to the machine 10.
The control module 44 is an electronic controller that is remotely coupled with an engine control module (ECM) of the engine 34 for carrying out various operations. The control module 44 may be a logic unit using any one or more of a processor, a microprocessor, and a microcontroller. The control module 44 may be based on an integrated circuitry, discrete components, or a combination of the two. Further, other peripheral circuitry, such as buffers, latches, switches, and the like may be implemented within the control module 44 or separately connected to the control module 44. It will be apparent to one skilled in the art that the control module 44 mentioned above may be an individual component which is in communication with other circuitries of the system 38. The control module 44 may be networked over a serial communication bus such as a controller area network (CAN) bus (not shown). Other arrangements of microcontrollers and microprocessors may be used. There may be several sensors connected to the control module 44 that provide the electronic controller with data for various operating conditions.

INDUSTRIAL APPLICABILITY

The system 38 controls dynamic events in the machine 10 by limiting operator action by magnitude control or rate of change control. The dynamic events may occur when the machine 10 is operated beyond its operating capability or conditions where the machine 10 is subjected to rapid change in material loads or sudden movement. The control module 44 may variably limit the action associated with the operator command, for example, the action may include movements of the load arm assembly 12 of the machine 10. The control module 44 may control the operating parameters of the machine 10 within the permissible range.
The system 38 is also applicable to the control other implements used on other machines, such as wheel type loaders, track type loaders, hydraulic excavators, backhoes, and similar vehicles having hydraulically operated implements. The system 38 controls the operation of the machine 10 by restricting the operator commands on the basis of loading ratio. The system 38 offers reliable operations, controls the machine 10 and also extends service life of components of the machine 10.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

What is claimed is:

1. A system for controlling operations of a machine, the system comprising:

a first sensor module configured to generate a signal indicative of an operator command;

a second sensor module configured to generate a signal indicative of a current loading ratio associated with a load arm assembly of the machine; and

a control module communicably coupled to the first sensor module and the second sensor module, the control module configured to:

receive a signal indicative of a current operating mode of the machine;

receive the signal indicative of the operator command and the signal indicative of the current loading ratio associated with the load arm assembly of the machine;

compare the current loading ratio with a pre-determined load rating of the machine; and

selectively limit an action associated with the operator command based on the comparison and the current operating mode of the machine.

2. The system of claim 1, wherein the operator command includes at least one of a lift command, and a tilt command.