System for controlling an actuator raising and lowering an excavation attachment, and track trencher equipped with such a system.

ES 2 397 798 T3

DESCRIPTION

System to control an actuator that raises and lowers an excavation attachment, and a trencher equipped with said system.

Technical Field

The present invention relates generally to the field of excavation, and more particularly to a system and process for controlling an excavation implement during excavation.

Background

Various types of excavation machinery initiate an excavation operation at a position above the ground 37 and employ an energized excavation tool to penetrate the ground to a specific depth d. Certain excavation machines are designed to initially excavate the earth in a generally vertical direction with respect to the soil surface, and then proceed with excavation in a generally horizontal direction. For these and other excavating machines, the time required to complete the initial vertical excavation effort is normally appreciable.

Such an excavating machine that performs an initial vertical excavation prior to a horizontal excavation is called a trencher. A trencher excavation machine 30, shown in FIGS. 1 and 2, typically includes a motor 36 coupled to a left drive wheel 32 and a right drive wheel 34 which together comprise a tractor portion 45 of trencher 30. An attachment 46, usually mounted on a davit 47, which is normally attached to the rear of the tractor part 45 and normally performs a specific type of digging operation.

A trencher chain 50 is frequently employed to excavate relatively large trenches at an appreciable rate. Trencher chain 50 generally remains on the ground in a transport configuration 56 when trencher 30 is operated around a job site. During excavation, the trencher chain 50 is lowered to an underground position 39, which penetrates the soil and excavates a trench to a desired depth and speed while in a trench formation configuration 58.

Another popular trenching accessory is referred to in the art as trencher wheel 60, shown in FIGURE 3, and can be operated in a manner similar to that of trencher chain 50. Additional accessories, such as TERRAIN LEVELER ™, manufactured by Vermeer Manufacturing Company of Pella, Iowa, are also known in the art and are also operated in a similar manner

A trencher excavation machine typically employs one or more sensors that monitor different physical parameters of the machine. The information collected from the sensors is generally used as an input to regulate the function of a particular machine, and / or to give information to an operator, usually by transducing a sensor signal for communication with one or more displays 500 or instruments. display, such as a tachometer, for example.

As shown in FIGURE 4, a manual jib position (up / down) switch 583 is normally provided to allow the operator to control the movement and vertical position of the attachment 46. An immersion switch 585 is normally provided to allow him to the operator to control the movement and position of the attachment davit 47 in conjunction with the engine speed feedback regulation 36. Feedback regulation typically monitors the speed of a motor 36 and reduces the speed of movement of an accessory davit 47 during light engine loading and increases the speed of movement of accessory davit 47 during light engine load. An attachment drive speed control 598 is typically provided to allow the operator to select and adjust the drive speed of attachment 46. Typically a 506 motor throttle is provided to limit the speed of the motor 36. These controls allow the operator to raise or lower the attachment 46 between the above ground position 37 and the below ground position 39 and perform a digging operation. called penetration cut.

Generally, it is desirable to maintain the motor 36 at a constant level of performance during excavation which, in turn, allows the trenching attachment 46 to operate at a constant level of trenching performance. In certain applications, it is desired to keep the motor 36 at its maximum power output level. Controlling the trencher 30 during penetration cut digging by employing a feedback control system as described in U.S. Patent 5,768,811, filed June 23, 1998, eliminates the need for the operator to make frequent adjustments to the 583 manual davit position switch. in order to maintain the engine 36 at a target engine performance level.

ES 2 397 798 T3

Document US 5,768,811 describes a system and a process for controlling an excavation, wherein a computer modifies the drive of the excavation device according to a performance parameter, with the aim of maintaining the engine at a predetermined performance level.

Document US 6,317,669, describes an automatic shovel and a related controller configured to store a plurality of working positions of the shovel.

Document US 5,975,214 describes machinery with a control device comprising a load sensing unit for detecting an applied load of a work plane and means for detecting positions of the work arms of the machinery; additionally, the control device comprises a unit that calculates the force exerted on said work plane.

Document US2005 / 7004734 describes a system and related method for controlling a mechanical arm, by means of planning, measuring and determining the path error.

WO 91/02853 describes machinery comprising means for producing a position signal in response to the position of a work implement; Those sensors include displacement sensors.

Document EPO 803 614 describes a control unit that calculates the position of a front device of a machinery according to the signals coming from the angle sensors and then calculates a target speed vector.

Document EP 0 905 325 describes a machinery having means of setting the target speed of movement and control means for receiving information of the setting of target speed of movement in order to make a working member retain a speed of movement. objective.

There is a desire among manufacturers of excavating machinery to minimize the difficulty of operating such machines and to increase their productivity while excavating and, more particularly, while penetrating. It is also desired that high levels of productivity be achieved while digging and penetration cutting through a variety of operating and environmental conditions and that excavating machinery can be adjusted and adapted to these varied conditions. Additionally, there is another desire among the operators of such excavating machinery to specify the desired depth to be excavated by the excavation machinery and to maintain the depth d automatically without further operator intervention. The present invention overcomes these and other needs.

Summary

According to the present invention a control system for controlling an actuator according to claim 1 is described.

Brief Description of Drawings

FIGURE 1 is a right side view of a trencher, including a trenching attachment with trencher chain operably mounted on an attachment davit;

FIGURE 2 is a generalized top view of the trencher, including a right drive wheel, a left drive wheel, and an accessory;

FIGURE 3 is a right side view of the trencher with a trenching attachment with a trencher wheel attached to it;

FIGURE 4 is a full elevation view of a prior art trencher control console incorporating an accessory speed control, an engine throttle, an accessory davit control, and a display;

FIGURE 5 is a full perspective view of a trencher control console incorporating a load control knob, an engine throttle, an attachment speed control, a manual davit control, a switch that enables self-dipping , and a screen with a plurality of menu navigation and selection buttons;

FIGURE 6 is a full elevation view of the control console of FIGURE 5;

ES 2 397 798 T3

FIGURE 7 is a left side view of the trencher of FIGURE 1 depicted with the attachment jib in an above ground configuration prior to performing a plunge cutting operation;

FIGURE 8 is a left side view of the trencher of FIGURE 1 depicted with the attachment jib transitioning from above ground to below ground configuration;

FIGURE 9 is a left side view of the trencher of FIGURE 1 depicted with the attachment jib in an under-ground configuration after completion of the plunge cutting operation;

FIGURE 10 is a left side view of an accessory davit actuator operably connected to a described davit position sensor in a retracted configuration;

FIGURE 11 is a left side view of the accessory davit and davit position sensor of FIGURE 10 depicted in an extended configuration;

FIGURE 12 is a block diagram illustrating a computer network for controlling the penetrating cutting operation of the trencher davit using the load control knob, switch enabling auto-dipping, manual davit control, the davit position sensor, and the screen with selection buttons and menu navigation;

FIGURE 12A is a block diagram illustrating an example list of variables related to a plurality of operator configurations used within the computer network of FIGURE 12;

FIGURE 12B is a block diagram illustrating an example list of variables related to a plurality of values ​​calculated and used within the computer network of FIGURE 12;

FIGURE 12C is a block diagram illustrating an example list of variables related to a plurality of preset configurations used within the computer network of FIGURE 12;

FIGURE 12D is a block diagram illustrating an example list of variables related to a plurality of calibrated values ​​used within the computer network of FIGURE 12;

FIGURE 13 plots a load multiplier vs. motor speed in a particular configuration and illustrates a modifiable load multiplier / motor speed proportional band with an upper limit and a lower limit;

FIGURE 14 illustrates the modifiable proportional band and graph of FIGURE 13 where the band location has been increased by turning the load control knob clockwise;

FIGURE 15 illustrates the modifiable proportional band and graphs FIGURE 13 where the location of the band has been reduced by turning the counter load control knob counterclockwise;

FIGURE 16 plots an accessory multiplier vs. accessory drive speed in a particular configuration and illustrates a modifiable accessory multiplier / accessory speed proportional band with an upper limit and a lower limit;

FIGURE 17 is a schematic diagram illustrating a controllable valve embodiment that receives signals from the computer network and regulates the movement and position of the accessory davit with feedback from the davit position sensor;

FIGURE 18 illustrates a control process for calculating the limits of the motor proportional speed band / load multiplier of FIGURES 13-15 giving the current input parameters;

FIGURE 19 illustrates a control process for calculating the load multiplier of FIGURES 13-15 given current input parameters;

FIGURE 20 illustrates a control process for calculating the accessory multiplier of FIGURE 16 given the current input parameters;

FIGURE 21 illustrates a control process for calculating a calculated davit descent current given the current input parameters;

ES 2 397 798 T3

FIGURE 22 illustrates a control process for calculating a preliminary davit down current and a preliminary davit up current giving the current input parameters;

FIGURE 23 illustrates a control process for calculating self-dipping descent current and a rising and falling current giving the current input parameters; Y

FIGURE 24 illustrates a control process for calculating a davit down current and a davit up current given the current input parameters.

Detailed description

The present invention is directed to a system and method for controlling a digging implement 51 of a digging machine while digging dirt between a position above the ground 37 and a position below the ground 39.

Referring now to FIGS. 7 through 9, there is illustrated a description of a trencher excavation machine 30 that includes a davit 47 rotatably mounted to a tractor portion 45 of trencher 30. Tractor portion 45 includes a drive wheel right 34, a left drive wheel 32, and a motor 36. The davit 47, on which an endless digging chain 50 is operably mounted, is moved between the below ground position and the above ground position 37 and 39 by actuation of a hydraulic cylinder 43 mounted to the davit 47 and the part of the tractor 45 from trencher 30. Cylinder 43 includes an extendable shaft 53 that is mechanically coupled to davit 47. Also coupled to cylinder 43 by a coupler 409 is a davit position sensor 408, as shown in FIGS. 10 and 11 that provides a davit position signal 410 to a computer network 182. As shown in FIGURE 17, a controllable valve 41 regulates the flow of hydraulic fluid to the hydraulic cylinder 43 in response to a boom down valve control signal 414 and a boom up valve control signal 415 generated by computer network 182, as will be described in greater detail below.

In an example configuration, the computer network 182 includes a plurality of controllers and other components that comply with a PLUS + 1 ™ standard defined by Sauer-Danfoss, Inc. of Ames, Iowa. The example controller modules include a module MC050-010 controller module, MC050-020 controller module, IX024-010 input module, and OX024-010 output module all of which are sold by Sauer-Danfoss, Inc. of Ames, Iowa. In an example configuration, various parameters are stored in non-volatile memory and a software code is maintained in an EPROM.

As shown in FIGURES 7 through 9 and 12, the davit 47 is a main component and structure of an accessory 46 that is further comprised of an accessory drive motor 48, which preferably draws power from an accessory drive pump 49. A speed sensor 186 is preferably coupled to accessory drive motor 48 and generates an accessory drive speed signal 324. The attachment drive pump 49, which draws power from the motor 36, preferably regulates the flow of hydraulic oil to the attachment drive motor 48 which, in turn, provides power for the attachment 46. The attachment drive pump 49 responds preferably to instructions communicated by an accessory drive pump signal 322 determined by computer network 182 as illustrated in FIGURE 12. Alternatively, the attachment control may operate on attachment motor 48. One or more attachment drive motors 48 and one or more attachment drive pumps 49 may be used in a parallel hydrostatic circuit.

In certain embodiments of the present invention, the drive of the accessory drive motor 48 is monitored by the speed sensor 186. The output signal 324 produced by the sensor 186 communicates with the computer network 182. In certain embodiments of the present invention, the operational hydraulic pressure created between attachment drive motor 48 and attachment drive pump 49 is monitored by a pressure sensor and communicated by an attachment hydrostatic drive pressure signal 323 to the computer network 182.

In a preferred embodiment, attachment 46 is attached to the rear of the tractor portion 45 of trencher 30. Various attachments 46 are known in the art, each specialized to perform a specific type of digging operation. FIGURE 1 illustrates one type of attachment 46 employing digging chain 50, and FIGURE 3 illustrates a trencher wheel attachment 46 60. Other accessories 46, such as a TERRAIN LEVELER ™, manufactured by the Vermeer Manufacturing Company of Pella, Iowa, are also known in the art. The present invention can be adapted to the various accessories 46 described herein and others.

In accordance with the embodiment illustrated in FIGS. 7 through 9, trencher 30 is initially positioned at a desired excavation location, with jib 47 raised to position above ground 37. A normal excavation effort involves two excavation operations. The first operation, called a penetration cut operation, involves cutting or otherwise removing soil between ground level (illustrated in FIGURE 8) and an excavation level below ground, indicated as a depth d in FIGURE 9 .A depth of

ES 2 397 798 T3 typical excavation, d, varies between approximately two feet to twenty feet for trencher 30 of the type illustrated in FIGURES 7 through 9. After completion of the penetration cutting operation with davit 47 penetrating the earth to the desired depth of excavation, d, the second excavation operation is optionally started, referred to as the trenching operation. A normal trenching procedure involves holding the davit 47 at the digging depth, d, and driving the tractor 45 and thereby the trencher attachment 30 in a desired direction, whereby a trench is cut from the location initial penetration cutoff to a desired end of the trench location.

Trench excavation results when hydraulic power is applied to attachment 46 and drive wheels 32 and 34 while trencher 30 is in the underground position 39. Penetration cut excavation results when hydraulic power is applied to the fitting 46 and to the davit cylinder 43 in the lowering direction of davit 47 (see FIGURE 17). Trenching and penetration shear can occur simultaneously resulting in a trench of increased depth d. During trench excavation, penetration cut excavation, or a combination of both, hydraulic energy induces movement in the active part of attachment 46, ie, excavation chain 50 or trencher wheel 60. Digging tools formed of a suitably hard material such as carbide teeth or other cutting implements are optionally mounted on the active part of the attachment 46. Hydraulic power provided to drive wheels 32 and 34 and / or davit cylinder 43 moves to the active part of attachment 46 which drives the underground portion of attachment 46 into unexcavated soil. The active part of the attachment 46 and tools are mounted to it to hook and break the soil away from the excavated area.

Performing a ground penetration cutting operation has several geophysical characteristics that will produce concomitant variations in excavation difficulty as the activated excavation chain 50 and davit move from position above ground 37, through varying soil, to the depth of excavation, d. Additionally, penetration cutting or trenching through the soil with significant geophysical variations in the adjacent layers can result in snagging and detachment of the hardened layer that is poorly supported by the soft adjacent layer. The hard peeled off discharge layer can get caught in the cutting implements and cause the digging chain 50 and attachment 46 to stop.

The control system responds automatically, without requiring operator intervention, to the accessory drive station 46 by raising the davit 47 until it is released. After this, the jib 47 is lowered again and penetration cuts and / or re-trenching.

The control system and method modifies, without requiring operator intervention, the drive of the digging implement 51 while digging soil between the position below ground and the position above ground in order to keep the motor 36 energizing the digging implement 51 at a target operating level in response to variations in engine load during excavation operation. Similarly, the control system and method simultaneously modifies the drive of the digging implement 51 in order to maintain the drive of attachment 46 at a target speed during digging.

The control system and method obtains and then maintains, without requiring operator intervention, the desired depth of excavation d. In one embodiment, a desired davit position (or davit cylinder) 432 is selected by the operator. The computer network 182 compares the desired davit position 432 with the davit position signal 410 transduced by the davit position sensor 408. A difference between the desired position 432 and the davit position signal 410 results in sending a corrective davit valve lowering signal 414 or a corrective davit valve raising signal 415 to the controllable valve 41. This results in movement of the davit 47 to a position closer to the desired position 432. This process is repeated iteratively until the desired position 432 is obtained. After this, the process is iteratively repeated to maintain the desired position 432, accommodating disturbances that can be introduced into the system.

In a preferred embodiment of the present invention, various signals and settings are used by the control system to carry out its various goals and functions. For the purposes of description, these variable control systems can generally be classified into seven main categories. These categories can overlap each other and are entered to organize this description. These and other elements of the present invention can also be classified by other methods and the following classification method should not be construed as placing any limitation on the present invention.

In certain embodiments, certain of the various signals and configurations 391, 392, 393, and 394 are stored in non-volatile memory within the computer network 182 as illustrated in FIGURE 12. Other signals and configurations may be represented by a output value of a control leveler or knob or a digital signal transmitted by a component such as motor 36.

The first category of control system signals and settings includes a group of presets 393 that are preset at the control system manufacturing. Examples of

These preset configurations 393 are illustrated in FIGURE 12C. These include a maximum engine operating speed 304 in revolutions per minute (RPM), a width 305 of a proportional band 330 in RPM, and a value 416 of a saturated valve command signal requesting maximum valve opening. Other embodiments of the present invention may allow some or all of the values ​​to be set and / or re-established at other times.

The second category of signals and settings includes a group of 394 calibrated values ​​derived during a calibration procedure. An example of these calibrated values ​​394 is illustrated in FIGURE 12D. This includes a davit downstream output signal threshold value 402 for controllable valve 41. The calibration method for determining this value simply increases the davit lowering valve control signal 414 to the controllable valve 41 until the cylinder roller 53 of the hydraulic cylinder 43 is moved. The value of the control signal 414 that motion is initiated then recorded as the davit descending threshold value of 402 and stored in computer network 182. In certain embodiments of the present invention, controllable valve 41 may be pre-calibrated or may not require calibration.

The third category of signals and settings includes a group of operator settings 391 established by the operator on an occasional basis, typically by accessing a control on an operator control console 52 (see FIGURES 5 and 6). Examples of these operator configurations 391 are illustrated in FIGURE 12A. Additional examples include an engine throttle setting 206, an accessory speed control setting 98, a self-dipping enable setting 185, and a load control signal 308 in percent. The load control signal 308 is preferably generated by a load control knob 380 which produces a signal of 0% when fully counterclockwise, 100% when fully clockwise, and proportional values ​​when are between these extremes. An operator screen 100 and soft menu navigation and selection buttons 102 provide access to view and edit various control system menu settings. Alternatively, the screen 100 can be tactile and / or navigated WITH the computer mouse. In a preferred embodiment, the editable settings through display 100 include a load limit control setting 303 in RPM, a davit drop speed limiting value 406 in percent, the desired davit position (or davit cylinder ) 432 in percent, the speed of an accessory drive proportional band lower limit 462, and the accessory drive speed proportional band upper limit 463. Various other access controls are optionally located on the operator control console 52. Certain operators and certain trenching and penetration cutting techniques may utilize one or more of these configurations on a continuous basis. In certain embodiments, some of these settings can be pre-set in the manufacture of the control system and cannot be modified by the operator.

The fourth category of signals and settings includes those settings adjusted by the operator on a continuous or more frequent basis, typically by accessing a control on the operator control console 52 (see FIGURES 5 and 6). An example of this includes a manual davit control switch 183 to operate the davit position 47 manually.

The fifth category of signals and configurations includes those signals that indicate a measured physical trencher 30 or environmental condition and / or a trencher 30 that is responsive to the control system and environment. Examples of these include an engine speed signal 312 in RPM generated by a sensor engine speed 208, the accessory drive speed signal 324 in RPM generated by the accessory drive speed sensor 186, the hydrostatic drive pressure of accessory 323, the davit (or davit cylinder) position signal 410 in percent, and various system and ambient temperatures.

The sixth category of signals and settings includes a group of calculated values ​​392 that are calculated by the computer network control system 182 for further use by the control system. Examples of these calculated values ​​392 are illustrated in FIGURE 12B. These include a 317 load multiplier, a motor speed proportional band / load multiplier lower limit 310, a 311 motor speed proportional band / load multiplier limit, an accessory multiplier 417, a down current calculated davit 442, a preliminary davit descent current 444, a preliminary davit ascending current 445, a self-dipping descent current 446, and a rising and penetrating current 447.

A seventh category of signals and settings includes those signals derived by the control system for control of a system parameter. Examples of these signals include the davit lowering valve control signal 414, the davit raising valve control signal 415, and the accessory drive pump signal 322.

The control system input signals and configurations described above can be generated by an operator selection of a discrete physical switch configuration (e.g., lift and penetration valve control signal 185), an operator selection of a continuous physical control configuration (for example, desired davit position 432), or an operator selection of a discrete configuration or

ES 2 397 798 T3 continues via operator display 100 and menu buttons 102 (eg load limit control setting 303). The method of accessing and changing this configuration as described above can be configured between the physical and virtual control system having access to points without departing from the true spirit of the present invention.

Referring now to the figures to facilitate an in-depth discussion, and more particularly to FIGURES 5 through 24, a self-dipping and davit depth control system for use with a trencher 30 is shown.

As discussed above, FIGURES 5 and 6 illustrate an embodiment of operator control console 52 with a plurality of physical and virtual access points that allow the operator to automatically or manually control the various functions associated with davit depth control. and penetration cut.

FIGURES 7 through 9 illustrate one embodiment of the kinematic layout and connections of davit 47, tractor 45, and hydraulic cylinder 43 that actuates the davit when davit 47 moves through its range of motion. FIGURES 10 and 11 further illustrate the davit acting on hydraulic cylinder 43 having a retracted length, R, and an extended length, R + E. In a preferred embodiment, the davit cylinder position sensor 408 is coupled to the hydraulic cylinder 43 by the coupler 409 such that any extension or retraction of the cylinder roller 53 produces a corresponding extension or retraction of the sensor 408. In one embodiment Preferably, sensor 408 is a Hall Effect sensor that produces an electrical signal proportional to the extent of sensor 408.

FIGURE 12 illustrates one embodiment of the various signals transmitted and received by the computer network and their connection to the various components of trencher 30. Additionally, various mechanical and hydraulic connections between the various components are illustrated.

FIGURES 13-15 illustrate a modifiable proportional band 330 where the relationship between the speed of the motor 312 and the load multiplier 317 is proportional. The operator can select and finally change the location of the proportional band 330 by increasing 331 or decreasing 332 by using the load control knob 380. As illustrated in FIGURE 14, a clockwise movement of the load control knob 380 increases the position 331 of the proportional band 330. Conversely, a counterclockwise movement of the load control knob 380 reduce position 332 as illustrated in FIGURE 15. The specific location of the load control knob 380 can be configured according to operator preference and / or the current penetration cut / trenching environment. Proportional band 330 and load multiplier 317, as shown in FIGURES 13-15 and calculated in FIGURES 18 and 19 describe a linear proportional relationship. In other embodiments of the present invention, other non-linear functional relationships can be used and other elements can be included, such as integrals and derivatives.

FIGURE 16 illustrates a modifiable proportional band 460 where the relationship between the drive speed of accessory 324 and accessory multiplier 417 is proportional. The operator can select and finally modify the location of the upper limit 463 of the proportional band 460 to the increase it 467 or reduce it 468. Similarly, the operator can select and finally modify the location of the lower limit 462 of the proportional band 460 by increasing it by 465 or decreasing it 466. Increasing 467 and 465 and decreasing 468 and 466 of limits 463 and 462 by using the operator display 100 and the software menu navigation and selection buttons 102 on the operator control console 52. The proportional band 460 and accessory multiplier 417, as shown in FIGURE 16 and calculated in FIGURE 20 describe a linear proportional relationship. In other embodiments of the present invention, other non-linear functional relationships can be used and other elements, such as damping can be included.

FIGURE 17 is a simplified schematic diagram illustrating a relationship between the computer network 182, the controllable valve 41, the hydraulic davit cylinder 43, the davit cylinder position sensor 408, a hydraulic supply pump 55, and a hydraulic tank 57. As mentioned above, the computer network 182 compares the position of the current davit cylinder 43, represented by the position signal of the davit cylinder 410, with the position of the desired davit cylinder 432 (see FIGURE 12). If it is desired to extend the position of the davit cylinder 43, the davit lowering valve control signal 414, as calculated in FIGS. 18 to 24, is transmitted to the controllable valve 41, shifting the spool to the left and causing pressure from supply pump 55 is sent along hydraulic line 59 to cylinder 43. This, in turn, causes cylinder roller 53 to extend and return hydraulic fluid to be sent to tank 57 along hydraulic conduit 61. If retraction of the position of the davit cylinder 43 is desired, the davit lift valve control signal 415, as calculated in FIGS. 18 to 24, is transmitted to the controllable valve 41, shifting the spool to the right. and causing pressure from supply pump 55 to be sent along hydraulic conduit 61 to cylinder 43. This, in turn, causes cylinder roller 53 to retract and return hydraulic fluid to be sent to tank 57 along hydraulic line 59. If no change in position of davit cylinder 43 is desired, do not sends signal to controllable valve 41 and the spool remains centered and blocking hydraulic lines 59 through 61. This, in turn, causes the spool roller to

ES 2 397 798 T3 cylinder 53 remains fixed. Other embodiments of the present invention may substitute for other valves that have different details but produce similar results.

FIGURES 18 through 24 describe an embodiment of the present invention in the context of flow charts that compute and manipulate various variable control systems to control the position of the davit 47 in the automatic and manual modes. It is anticipated that other algorithms can be created resulting in equivalent relationships between the various variables.

FIGURE 18 illustrates a method by which the upper limit 311 and the lower limit 310 of the proportional band 330 are calculated and stored. The inputs for this method are retrieved in steps 602 to 608 and include the maximum motor operating speed 304 in step 602, the proportional band width 305 in step 604, the load limit control setting 303 in step 606, and the load control setting 308 at step 608. The lower limit 310 is calculated as shown in step 610 and stored and the upper limit 311 is calculated as shown in step 612 and stored. Then the calculation cycle is repeated.

FIGURE 19 illustrates a method by which the load multiplier 317 is calculated and stored. The inputs for this method are retrieved in steps 620 to 626 and include the current engine speed 312 in step 620, the lower limit 310 in step 622 and the upper limit 311 in step 624 of the proportional band 330, and the width of the proportional band 305 in step 626. The speed of the motor 312 is tested in step 628 and if it is found to be less than or equal to the lower limit 310, then the load multiplier 317 is set to 0% in step 630 and stored. If there is no result from step 628, the speed of the motor 312 is tested in step 632. If the speed of the motor 312 is found to be within the upper limit 311 and the lower limit 310, then the load multiplier 317 is calculated as shown in step 634 and stored. If there is no result from step 632, the speed of the motor 312 is tested in step 636. If the speed of the motor 312 is found to be greater than or equal to the upper limit 311, then the load multiplier 317 is set to 100 % in step 638 and stored. If there is no result from step 636, then an out of range fault is generated at step 640. The calculation cycle repeats after load multiplier 317 is stored or after step 640.

FIGURE 20 illustrates a method by which accessory multiplier 417 is calculated and stored. The inputs for this method are retrieved in steps 660 to 664 and include the accessory drive speed 324 in step 660 and the lower limit 462 in step 662 and the upper limit 463 in step 664 of the proportional speed band. accessory 460. The accessory drive speed 324 is tested in step 668 and if it is found to be less than or equal to the lower limit 462, then the accessory multiplier 417 is set to 0% in step 670 and stored. If there is no result in step 668, the drive speed of accessory 324 is tested in step 672. If the accessory drive speed 324 is found to be within the upper limit 463 and the lower limit 462, then the accessory multiplier 417 is calculated as shown in step 674 and stored. If there is no result in step 672, the drive speed of accessory 324 is tested in step 676. If the accessory drive speed 324 is found to be greater than or equal to the upper limit 463, then the accessory multiplier 417 is set to 100% in step 678 and stored. If there is no result in step 676, then out of range fault is generated in step 680. The calculation cycle repeats after accessory multiplier 417 is stored or after step 680.

A feature in certain embodiments of the present invention relates to load multiplier 317 and associated operator modifiable proportional band 330 shown in FIGS. 13-15 and calculated in FIGURES 18 and 19. Load multiplier 317 provides feedback 36 for the control system and is used to calculate the calculated davit downdraft 442 as shown in FIGURE

twenty-one. Additionally, a feature in certain embodiments of the present invention relates to accessory multiplier 417 and associated operator modifiable proportional band 460 shown in FIGURE 16 and calculated in FIGURE 20. The accessory multiplier 417 provides accessory 324 drive speed feedback to the control system and is also used to calculate the calculated davit downdraft 442 as shown in FIGURE 21. The calculated davit downdraft 442 is additionally used as the preliminary davit descent current 444 if certain tests are met as shown in FIGURE 22. The preliminary davit descent current 444 is additionally used as the descent and self-dipping current 446 if certain tests are met as shown in FIGURE 23. The descent and self-dipping current 446 is additionally used as the davit descent current 414 and is sent to controllable valve 41 if certain tests are met as shown in FIGURE 24.

Load multiplier 317 and proportional band 330 provide a benefit of continually adjusting the calculated jib descent current 442 based on motor load. This allows the motor 36 to continuously operate at high levels of performance and thus the trencher 30 achieves high levels of production. In other words, if the trencher 30 encounters the compacted soil in such a way that the speed of the motor 312 is reduced during the penetration cut operation, the load multiplier 317 is reduced which also results in a reduction in the down current. calculated davit current 442. In the event that the calculated davit descent current 442 also becomes the davit descent current 414 (as described in

ES 2 397 798 T3 previous paragraph), the controllable valve 41 reduces the penetration rate of the davit 47 and thus relieves some of the load on the motor 36 and allows the speed of the motor 312 to be increased. loose in such a way that the speed of the motor 312 is increased, the load multiplier 317 is increased. This correspondingly results in an increase in the penetration rate of the davit 47. This action increases the load on the motor 36 and reduces the speed of the motor 312. By proper adjustment of the variable control systems, the speed of the motor 312 can be maintained in a high performance region and the davit penetration rate 47 it can be continuously and automatically adjusted for this purpose.

The 417 accessory multiplier and 460 proportional band provide a benefit for continuously adjusting the calculated davit descent current 442 based on the 324 accessory drive speed. This allows the 324 accessory drive speed to continuously operate close to its target speed. In other words, if trencher 30 encounters compacted soil such that the drive speed of attachment 324 reduces during a penetration cut operation, attachment multiplier 417 is reduced which also results in a reduction in drive current. calculated davit descent 442. In the event that the calculated davit descent current 442 also becomes the davit descent current 414 (as described in the two preceding paragraphs), the controllable valve 41 reduces the davit penetration rate 47 and thereby alleviates some loads attachment motor 48 and allows attachment drive speed 324 to be increased. Conversely, if the ground is found to be loose such that the drive speed of attachment 324 is increased, the attachment multiplier 417 is increased correspondingly resulting in an increase in the penetration rate of davit 47. This action increases the load on the attachment motor 48 and reduces the drive speed of attachment 324. By proper adjustment of the variable control systems, the drive speed of attachment 324 can be maintained in a desired region and the penetration rate of davit 47 can be continuously and automatically adjusted for this purpose.

Provisions that allow the operator to adjust the proportional band 330 by turning the load control knob 380 provide a benefit that allows the operator to adjust the trencher 30 to a given environment or desired performance. Charge motor 36 uses differently available horsepower and torque differently and thus allows trenching results to vary and adjust. Similarly, the provisions that allow the operator to adjust the speed proportional band of the attachment 460 provide a benefit that allows the operator to further adjust the trencher 30. The load of attachment motor 48 allows differently than the results of the attachment. trench formation vary and adjust.

Now referring to FIGURE 21, a method for calculating and storing the calculated jib descent current 442 is illustrated. This method uses accessory multiplier 417 and load multiplier 317 providing feedback, as discussed above. The inputs for this method are retrieved in steps 700 to 708 and include the maximum davit current 416 in step 700, the davit drop rate limiter 406 in step 702, the accessory multiplier 417 in step 704, the load multiplier 317 in step 706, and the davit current threshold 402 in step 708. The calculated davit descent current 442 is calculated as shown in step 710 and stored. The calculation cycle then repeats.

FIGURE 22 illustrates a method by which the preliminary davit descending current 444 and the preliminary davit ascending current 445 are calculated and stored. This method allows the control system to automatically control the position of the davit in order to achieve and maintain the desired position of the 432 davit cylinder. The inputs for this method are retrieved in steps 720 to 726 and include the maximum davit current 416 in step 720, the calculated davit descent current 442 in step 722, the desired position of the davit cylinder 432 in step 724, and the current davit cylinder position 410 in step 726. The current davit cylinder position 410 is tested in step 728 and if it is found to be less than the desired position of the davit cylinder 432, then the preliminary davit lowering current 444 is set equal to the davit lowering current. calculated 442 in step 730 and stored and the preliminary davit rise current 445 is set equal to zero in step 732 and stored. If there is no result in step 728, the current davit cylinder position 410 is tested in step 734 and if it is found to be equal to the desired position of davit cylinder 432, then the preliminary davit lowering current 444 is is set equal to zero in step 736 and is stored and the preliminary davit upstream current 445 is set equal to zero in step 738 and is stored. If there is no result in step 734, the current davit cylinder position 410 is tested in step 740 and if it is found to be greater than the desired position of the davit cylinder 432, then the preliminary davit lowering current 444 is set equal to zero in step 742 and is stored and the preliminary davit upstream current 445 is set equal to the maximum davit current 416 in step 744 and is stored. If there is no result in step 740, then an out-of-range fault is generated in step 746. The calculation cycle repeats after the preliminary davit down current 444 and the preliminary davit up current 445 is stored. or then proceed to step 746. This method may also include and incorporate control system techniques known in the art such as providing a dead band at steps 728, 734, and 740. This method may further include and incorporate such control system techniques as a PID loop to achieve the desired position of the davit cylinder 432.

ES 2 397 798 T3

FIGURE 23 illustrates a method by which the dip and dip current 446 and the dip and dip current 447 are calculated and stored. This method allows the control system to automatically interrupt the penetration cutting and / or trenching process and raise the jib 47 when the traction attachment has stalled and resume after recovery. The inputs for this method are retrieved in steps 760 to 766 and include the maximum davit current 416 at the top 760, the preliminary davit descent current 444 in step 762, the preliminary davit rise current 445 in the step 764, and the accessory drive speed 324 in step 766. The accessory drive speed 324 is tested in step 768 and if it is found to be zero, then the dip and dip current 446 is set equal to zero in step 770 and is stored and the creep and dip current 447 is set to zero. set equal to the maximum davit current 416 in step 772 and stored. If there is no result in step 768, then the dip and dip current 446 is set equal to the preliminary davit downstream current 444 in step 774 and is stored and the rise and dip current 447 is set equal to the current davit lift 445 at step 776 and stored. The calculation cycle then repeats. This method can also include and incorporate control system techniques known in the art such as providing a dead band at step 768.

FIGURE 24 illustrates a method by which the jib descent current 414 and the jib ascent current 415 are calculated and stored. This method allows automatic davit depth and self-dive control to be made possible. This method also allows the control system to interrupt the automatic boom depth control and auto-dive functions when the operator activates manual boom control 183 and resumes after deactivation. Additionally, this method allows the manual davit control 183 to function for use with the automatic davit depth control and auto-dive functions disabled. The inputs for this method are retrieved in steps 800 to 808 and include the maximum davit current 416 in step 800, the switch that enables the self-dipping position 185 in step 802, the manual davit control switch position 183 in step 804, the sinking and self-dipping current 446 in step 806, and the rising and penetrating current 447 in step 808. The position of the manual davit control switch 183 is tested in step 810 and found to be UP, then the davit descent current 414 is set equal to zero in step 812 and the davit up current is stored and 415 is set equal to the maximum davit current 416 in step 814 and stored. If there is no result in step 810, then the position of manual davit control switch 183 is tested in step 816 and found to be DOWN, then the davit descent current 414 is set equal to the maximum davit current. 416 in step 818 and is stored and the jib up current 415 is set equal to zero in step 820 and is stored. If there is no result in step 816, then the position of the manual davit control switch 183 is tested in step 822 and if it is found to be OFF, then the position of the switch that enables self-dipping 185 is tested in step 824. and if it is found to be ON, then the davit down current 414 is set equal to the dip and dip current 446 in step 826 and is stored and the davit up current 415 is set equal to the up and down current 447 in step 828 and is stored. If there is no result from step 824, then the position of the switch that enables self-dipping 185 is tested in step 830 and if it is found to be OFF, then the davit descent current 414 is set equal to zero in step 832. and is stored and the boom up current 415 is set equal to zero in step 834 and is stored. If there is no result in step 830, then an out of range fault is generated in step 836. If there is no result in step 822, then an out-of-range fault is generated in step 838. The calculation cycle repeats after the davit down current 414 and the upward davit current 415 are stored or after of stages 836 or 838.

The computer network 182 described in this specification may include one or more computer devices. These computer devices can be physically distributed throughout the trencher 30 and can be incorporated into certain components of the trencher 30, for example the engine control system 36 can have a computer device that is incorporated into the computer network. 182. Computer devices can be known by various names including controller and computer. Computer devices can be digital or analog and can be programmed by software.

In certain cases, the above description references a specific set of units when discussing a particular variable, for example RPM. It is anticipated that an alternate system of units can be used in each of these cases. It is further anticipated that a transformed system of units can be used when desired, for example the desired davit cylinder position in percent can be transformed into the desired davit position in degrees.

Certain signals were described above and in the figures in terms of the specific signal types and units, for example the load control signal 308 is described as having a range of 0% to 100% and the controllable valve signals 414 and 415 is described as using milliamps (mA) of electrical current. Various other signal types and units can be substituted for those described above without departing from the true spirit of the present invention, for example the load control signal 308 can be replaced with a pulse-width modulation (PWM) signal. Similarly, these signals can also be transformed from

ES 2 397 798 T3 type of signal to the type of signal within the control system itself, for example the signals of the controllable valve 414 and 415 can originate a digital digital signal in the computer network 182 and are transformed into a signal of millivolts (mV). These transformations can occur at various locations including within the device generating the signal, within a signal converter, within a controller, and / or within the computer network 182.

The above specification states embodiments of the present invention having various feedback control loops. Many types of loop control are known in the art. Included in these various methods of calculating error, correction gains, ramp times, delays, value averaging, hysteresis, Proportional Integral Derivative, and other mathematical loop control techniques. It is anticipated that certain of these methods can be combined and implemented with the embodiments described above.

The above specification sets forth embodiments of the present invention that receive feedback from motor 36 and accessory drive speed 324 for use in controlling the rate of movement of davit 47. Other embodiments of the present invention receive feedback from other parameters, such as accessory drive pressure 323, which are also used for this purpose.

Electrical and mechanical actuators are known in the art. Additionally, a motor can power an electrical and / or mechanical actuator, and the actuator can be operatively connected to a davit. It is anticipated that the above actuator may be replaced by hydraulic cylinder 43, controllable valve 41, and supply pump 55 in the above specification. The control system of the current description can be adapted to control the above actuator.

The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Because many embodiments of the invention can be made without departing from the spirit and scope of the invention which is defined by the appended claims.