EP1765653A1

EP1765653A1 - A motor mount assembly for controlling a mobile machine

Info

Publication number: EP1765653A1
Application number: EP05756567A
Authority: EP
Inventors: David Green; Arthur F. Lange; James Veneziano
Original assignee: Trimble Navigation Ltd
Current assignee: Trimble Inc
Priority date: 2004-07-14
Filing date: 2005-05-31
Publication date: 2007-03-28
Also published as: WO2006019462A1

Abstract

This writing discusses a motor assembly comprising a lower motor mount and an upper motor mount. The lower motor mount is mechanically coupled with a steering column of a mobile machine. The upper motor mount is coupled with the lower motor mount and with a drive motor. The upper motor mount maintains pressure when in a first position such that a drive wheel coupled with the drive motor stays in contact with a steering wheel of a vehicle of a mobile machine. When the upper motor mount is locked in a second position, the drive wheel is kept away from the steering wheel of the mobile machine.

Description

A MOTOR POUNT ASSEIVIBtY FOR CONTROLLING A MOBILE MACHINE

FIELD

Embodiments here described are directed to controlling a mobile machine. More specifically, the embodiments relate to an assembly for coupling a steering component of a vehicle control system with a mobile machine.

RELATED APPLICATIONS

The present invention is a continuation in part of co-pending and

commonly owned U.S.P.T.O. application No. 10/892,002 filed July 14, 2004 titled

A Method and System for Controlling a Mobile Machine by Arthur Lange and

James Veneziano, assigned to the assignee of the present invention, and which

is hereby incorporated by reference in its entirety herein.

BACKGROUND

Operating agricultural vehicle such as tractors and harvesters often

requires highly repetitive operations. For example, when plowing or planting a .

field, an operator must make repeated passes across a field. Due to the

repetitive nature of the work and irregularities in the. terrain, gaps and overlaps in

the rows of crops can occur. This can result in damaged crops, overplanting, or

reduced yield per acre. As the size of agricultural vehicles and farming implements continues to increase, precisely controlling their motion becomes

more important.

Guidance systems are increasingly used for controlling agricultural and

environmental management equipment and operations such as road side

spraying, road salting, and snow plowing where following a previously defined

route is desirable. This allows more precise control of the vehicles than is

typically realized than if the vehicle is steered by a human. Many rely upon

furrow followers which mechanically detect whether the vehicle is moving parallel

to a previously plowed plant furrow. However, these guidance systems are most

effective in flat terrain and when detecting furrows plowed in a straight line.

Additionally, many of these systems require factory installation and are too

expensive or inconvenient to facilitate after market installation.

A component for controlling the steering mechanism of the vehicle is used

to control the movement of the vehicle in a desired direction. Thus, the guidance

system generates a steering command which is implemented by the component

which controls the steering mechanism. Often, the controlling component is

directly coupled with and manipulates hydraulic pumps which comprise the power

steering system of the vehicle. Other controlling components manipulate the

steering wheel of the vehicle. Figure 5 shows a side view of an exemplary prior art motor mount 500. In

Figure 5, a electric motor 510 is coupled with a thrust bearing 511. A shaft 520

coupled with motor 510 passes through thrust bearing 511 and is coupled with

wheel 521. Thrust bearing 511 is coupled with a back plate 540 via a screw 512

which defines a point of rotation for thrust bearing 511. A screw 530 couples

spring 531 with back plate 540 which is in turn coupled with, for example, the

steering column of the vehicle being controlled. A lever 550 is coupled with back

plate 540 via screw which defines a point of rotation for lever 550. A screw 552

extends from lever 550 and overlies electric motor 510.

Figure 5 shows motor mount 500 in an engaged position in which wheel

521 contacts steering wheel 560. To disengage wheel 521 from steering wheel

560, lever 550 is pulled in the direction typically shown as arrow 570. As a result,

lever 550 rotates around screw 551 , thus causing screw 552 to move over the

back of electric motor 510 and engage a groove 513 cut into the housing of

electric motor 510. This in turn causes thrust bearing 511 to rotate around screw

512, which results in wheel 521 moving in the direction typically shown as arrow

580 and compressing spring 590. To disengage wheel 521 from steering wheel

560, lever 550 is moved in the opposite direction to disengage screw 552 from

groove 552. Motor mount 500 is problematic in that after repeated use, groove 513

becomes worn such that it becomes difficult for screw 552 to remain engaged in

groove 513. As a result, wheel 521 can unintentionally become engaged with

steering wheel 560. For example, if a user is manually steering a vehicle and hits

a bump, wheel 521 can become engaged with steering wheel 560. This can be

especially dangerous if the guidance system is generating steering commands at

that moment as the vehicle may be steered in an un-intended direction as a

result.

Another drawback of motor mount 500 is that screw 512 uses a lock nut

having a nylon insert to maintain a desired amount of tightness. Over time, the

nylon insert becomes worn, thus allowing thrust bearing 511 to move out of

plane. This results in reduced precision for the guidance system because when

electric motor implements steering commands, torque induced by the turning of

motor 510 causes the out of plane movement. As a result, friction between

wheel 521 and steering wheel 560 is lost which can result in a loss of steering

precision.

Additionally, adjustment of the torque applied to screw 512 during

assembly necessitates some degree of skill on the part of the assembler. For

example, if screw 512 is tightened too much, it becomes too difficult to rotate

thrust bearing 511 around the axis defined by screw 512. However, not tightening screw 512 enough introduces a loss of precision as described above.

This is further complicated by the nylon inserts themselves which typically exhibit

a wide range of tolerance with respect to the amount of torque that can be

applied. As a result, the person assembling motor mount 500 has to learn by

experience how much torque to apply during assembly.

SUMMARY

Accordingly, a need exists for motor mount for a vehicle controller which

minimizes the amount of out of plane movement of the motor with respect to a

steering wheel of the vehicle being controlled. While meeting the above stated

need, it is advantageous that the motor mount can positively disengage the

vehicle controller when desired. While meeting the above stated needs, it is

advantageous that the motor mount can be manufactured economically and

without requiring specially trained assembly personnel.

Embodiments here presented disclose a motor assembly comprising

a lower motor mount and an upper motor mount. The lower motor mount is

mechanically coupled with a steering column of a mobile machine. The upper

motor mount is coupled with the lower motor mount and with a drive motor. The

upper motor mount maintains pressure when in a first position such that a drive

wheel coupled with the drive motor stays in contact with a steering wheel of a

vehicle of a mobile machine. When the upper motor mount is locked in a second

position, the drive wheel is kept away from the steering wheel of the mobile

machine. BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of

this specification, illustrate embodiments of the present invention and, together

with the description, serve to explain the principles of the invention. Unless

specifically noted, the drawings referred to in this description should be

understood as not being drawn to scale.

FIGURES 1 A and 1 B show an exemplary system for controlling a mobile

machine in accordance with embodiments of the present invention.

FIGURE 2 shows an exemplary system architecture in accordance with

embodiments of the present invention.

FIGURES 3A and 3B show side and top views respectively of a system for

controlling a mobile machine in accordance with embodiments of the present

invention.

FIGURES 4A and 4B show side and top views respectively of a system for

controlling a mobile machine in accordance with embodiments of the present

invention. FIGURE 5 shows a side view of an exemplary prior art motor mount.

FIGURE 6 shows a perspective view of a motor mount assembly 600 in

accordance with embodiments of the present invention.

FIGURE 7 is an exploded perspective view of a motor mount assembly in

accordance with embodiments of the present invention.

FIGURES 8A, 8B, and 8C show front, top, and perspective views

respectively of a lower motor mount in accordance with embodiments of the

present invention.

FIGURES 9A, 9B, 9C₁ 9D, and 9E show front, side, top, bottom, and rear

views respectively of an upper motor mount in accordance with embodiments of

the present invention.

FIGURES 10A and 1 OB show side and front views respectively of a pivot

shaft in accordance with embodiments of the present invention.

FIGURES 11 A₁ 11 B, and 11 C show an exploded perspective, side and

rear views respectively of a pivot shaft and upper motor mount in accordance

with embodiments of the present invention. FIGURE 12 is an exploded perspective view of upper motor mount and

lower motor mount in accordance with embodiments of the present invention.

FIGURE 13 is a section view of a pivot shaft and pivot bearing in

accordance with embodiments of the present invention.

FIGURES 14A and 14B are front views of a motor mount assembly 600

used in accordance with embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to embodiments of the present

invention, examples of which are illustrated in the accompanying drawings.

While the present invention will be described in conjunction with the following

embodiments, it will be understood that they are not intended to limit the present

invention to these embodiments alone. On the contrary, the present invention is

intended to cover alternatives, modifications, and equivalents which may be

included within the spirit and scope of the present invention as defined by the

appended claims. Furthermore, in the following detailed description of the

present invention, numerous specific details are set forth in order to provide a

thorough understanding of the present invention. However, embodiments of the

present invention may be practiced without these specific details. In other

instances, well-known methods, procedures, components, and circuits have not

been described in detail so as not to unnecessarily obscure aspects of the

present invention.

Figure 1 is a block diagram of an exemplary system 100 for controlling a

mobile machine 105 in accordance with embodiments of the present invention.

In Figure 1 , a position determining system is coupled with a control component

120 and a steering component 130 via a communication network or coupling 1 15.

Additionally, system 100 may comprise an optional keypad 140 and/or a terrain compensation module component (e.g., TCM 150) which are also coupled with

coupling 1 15.

In embodiments of the present invention, coupling 115 is a serial

communications bus. In one embodiment, coupling 115 is compliant with, but not

limited to, the controller area network (CAN) protocol. CAN is a serial bus

system which was developed for automotive use in the early 1980s. The Society

of Automotive Engineers (SAE) has developed a standard CAN protocol, SAE

J1939, based upon CAN specification 2.0. The SAE J1939 specification provides

plug-and-play capabilities and allows components from various suppliers to be

easily integrated in an open architecture.

Position determining system 110 determines the geographic position of

mobile machine 105. For the purposes of the present invention, the term

"geographic position" means the determining in at least two dimensions (e.g.,

latitude and longitude), the location of mobile machine 105. In one embodiment

of the present invention, position determining system 110 is a satellite based

position determining system and receives navigation data from satellites via

antenna 107 of Figure 1 B. Examples of satellite based position determining

systems include the global positioning system (GPS) navigation system, a

differential GPS system, a real-time kinematics (RTK) system, a networked RTK

system, etc. While the present embodiment recites these position determining systems specifically, it is appreciated that embodiments of the present invention

are well suited for using other position determining systems as well such as

ground-based position determining systems, or other satellite-based position

determining systems such as the GLONASS system, or the Galileo system

currently under development.

In embodiments of the present invention, control component 120 receives

position data from position determining system 110 and generates commands for

controlling mobile machine 105. In embodiments of the present invention, mobile

machine 105 is an agricultural vehicle such as a tractor, a harvester, etc.

However, embodiments of the present invention are well suited for controlling

other vehicles such as snow plows, road salting, or roadside spraying equipment

as well. In one embodiment, in response to position data received from position

determining system 110, control component 120 generates a message (e.g., a

steering command) to steering component 130 which then controls the steering

mechanism of mobile machine 105. In embodiments of the present invention,

control component 120 is operable for generating steering commands to an

electrical steering component and a hydraulic steering component depending

upon the configuration of system 100.

In embodiments of the present invention, keypad 130 provides additional

input/output capabilities to system 100. In embodiments of the present invention, keypad 130 may also comprise a device drive which allows reading a media

storage device such as a compact disk (CD), a digital versatile disk (DVD), a

memory stick, or the like. This allows, for example, integrating data from various

software applications such as mapping software in order to facilitate controlling

the movement of mobile machine 105. For example, field boundaries can be

easily input into system 100 to facilitate controlling the movement of mobile

machine 105.

TCM 150 provides the ability to compensate for terrain variations which

can reduce the precision of position determining system 110 in determining the

geographic position of mobile machine 105. For example, when traversing a

hillside, the antenna 107 of the position determining system 110 can be

displaced to one side or the other with respect to the center line of mobile

machine 105, thus causing errors in determining the geographic position of

mobile machine 105. As a result, gaps or overlaps can occur when plowing

across contoured terrain is being performed. TCM 150 can detect the magnitude

of displacement of antenna 107 with respect to the center line of mobile machine

105 (e.g., due to roll, pitch, and yaw) and send signals which allow control

component 120 to generate steering commands which compensate for the errors

in determining the geographic position of mobile machine 105. It is appreciated

that the components described with reference to Figure 1 may be implemented

as separate components. However, in embodiments of the present invention, these components may be integrated as various combinations of discreet

components, or as a single device.

Figure 2 shows an exemplary system architecture 200 in accordance with

embodiments of the present invention, in the embodiment of Figure 2, control

component 120 comprises a vehicle guidance system 210 which is coupled with

a steering controller 220. It is appreciated that in embodiments of the present

invention, vehicle guidance system 210 and steering controller 220 may be

implemented as a single unit, or separately. Implementing steering controller 220

separately is advantageous in that it facilitates implementing the present

invention as an after market kit which can be easily added to an existing vehicle

navigation system. As a result, the costs for components and for installation of

the control system of the present invention are reduced. However, embodiments

of the present invention are well suited to be factory installed as original equipment for mobile machine 105 as well.

In embodiments of the present invention, vehicle guidance system 210

uses position data from position determining system 110, user input such as a

desired pattern or direction, as well as vector data such as desired direction and

distance to determine course corrections which are used for guiding mobile

machine 105. Roll, pitch, and yaw data from TCM 150 may also be used to

determine course corrections for mobile machine 105. For purposes of the present invention, the term "course correction" means a change in the direction

traveled by mobile machine 105 such that mobile machine 105 is guided from a

current direction of travel to a desired direction of travel. In embodiments of the

present invention, vehicle guidance system 210 is a commercially available

guidance system such as the AgGPS® guidance system manufactured by

Trimble Navigation Ltd. of Sunnyvale California.

Additional data used to determine course corrections may also comprise

swath calculation which takes into account the width of various implements which

may be coupled with mobile machine 105. For example, if a harvester can clear

a swath of 15 feet in each pass, vehicle guidance system 210 may generate

steering commands which cause mobile machine 105 to move 15 feet to one

side in the next pass. Vehicle guidance system 210 may also be programmed to

follow straight or curved paths which is useful when operating in irregularly

shaped or contoured fields or in fields disposed around a center pivot. This is

also useful in situations in which the path being followed by mobile machine 105

is obscured. For example, an operator of a snowplow may not be able to see the

road being cleared due to the accumulation of snow on the road. Additionally,

visibility may be obscured by snow, rain, or fog. Thus, it would be advantageous

to utilize embodiments of the present invention to guide mobile machine 105 in

these conditions. In embodiments of the present invention, position determining

component 110 may be integrated into vehicle guidance system 210 or may be a separate unit. Additionally, as stated above with reference to Figure 1 , position

determining component 1 10, control component 120 and steering component

130 may be integrated into a single unit in embodiments of the present invention.

In embodiments of the present invention, the course correction calculated

by vehicle guidance system 210 is sent from vehicle guidance system 210 to

steering controller 220.

Steering controller 220 translates the course correction generated by

guidance system 210 into a steering command for manipulating the steering

mechanism of mobile machine 105. Steering controller 220 generates a

message conveying the steering command to steering component 130. In

embodiments of the present invention, the communicative coupling. between

vehicle guidance system 210, steering controller 220 and steering component

130 is accomplished using coupling 115 (e.g., a serial bus, or CAN bus).

lri embodiments of the present invention, steering component 130 may

comprise an electric steering component 131 , or a hydraulic steering component

132. Thus, as shown in Figure 2, steering controller 220 comprises a first output

221 for coupling steering controller 220 with electric steering component 131 , and

a second output 222 for coupling steering controller 220 with hydraulic steering

component 132. Because coupling 1 15 may be compliant with the CAN protocol, plug and play functionality is facilitated in system 200. Therefore, in

embodiments of the present invention, steering controller can determine which

steering component it is coupled with depending upon which output of steering

controller 220 is used.

Steering controller 220 then generates a message, based upon the

steering component with which it is coupled, which causes the steering

component to actuate the steering mechanism of mobile machine 105. For

example, if steering controller 220 determines that output 221 is being used, it

generates a steering command which is formatted for controlling electric steering

component 131. If steering controller 220 determines that output 222 is being

used, it generates a steering command which is formatted for controlling

hydraulic steering component 132.

Figures 3A and 3B show side and top views respectively of a system 300

for controlling a mobile machine in accordance with embodiments of the present

invention. In the embodiment of Figure 3A, a steering component (e.g., electric

steering component 131 of Figure 2) comprises an electric motor 310 which is

coupled with an actuator device via a shaft 312. In the embodiment of Figure 3A,

actuator device comprises a drive wheel 311 which is in contact with steering

wheel 330 of mobile machine 105. In embodiments of the present invention,

electric motor 310 may be directly coupled with drive wheel 311 , or may be coupled via a low ratio gear (not shown). Using these methods to couple electric

motor 313 and drive wheel 311 are advantageous in that a smaller electric motor

can be used while still generating sufficient torque to control steering wheel 330.

Thus, if a user wants to manually steer mobile machine 105, the user will

encounter less resistance from electric motor 310 when it is disengaged.

In embodiments of the present invention, the electric motor coupled with

drive wheel 311 is a non-geared motor and the performance parameters of the

electric motor coupled are selected so that, for example, electric motor 310 may

be installed in a variety of vehicle types and/or manufacturers. For example, a

certain amount of torque is desired in order to be able to turn steering wheel 330.

It is also important to determine a desired ratio between the torque generated by

the motor and the electrical current driving the motor. Because there is a power

loss across the transistors comprising control component 120 that are

proportional to the square (X²) of the current passing through the circuit, it is

desirable to utilize a lower amount of current. However, if too little current is

used, the motor turns too slowly to provide a desired level of responsiveness to

steering commands. Additionally, if the torque constant (e.g., ounce/inches per

amp) is too high, excessive "back-EMF," which is an electro-magnetic field, is

generated by the motor and interferes with the current flowing into the motor.

While a higher voltage can overcome the back-EMF issue, most vehicles utilize

12 volt batteries, thus indicating that a higher amount of current is desired. In embodiments of the present invention, a non-geared electric motor which

generates approximately nineteen ounce/inches of torque per amp of current is

utilized. In other embodiments of the present invention, the performance

parameters of the electric motor are selected to more specifically match the

motor with a particular vehicle type, model, or manufacturer.

Electric steering component 131 further comprises a motor control unit

313 is coupled with electric motor 310 and with a control component 120 of

Figure 2 via coupling 115. In Figure 3A, electric motor 310 is coupled with the

steering column 340 via a bracket 320. It is appreciated that in embodiments of

the present invention, electric motor 310 may be coupled with steering column

340 using another apparatus than bracket 320. For example, in one

embodiment, electric motor 310 may be coupled with a bracket which is attached

via suction cups with the windshield or dashboard of mobile machine 105. In

another embodiment, electric motor 310 may be coupled with a pole which is

extended between the floor and roof of mobile machine 105. Furthermore, while

the present embodiment shows motor control unit 313 directly coupled with

electric motor 310, embodiments of the present invention are well suited to utilize

other configurations. For example, in one embodiment motor control unit 313

may be implemented as a sub-component of control unit 120 and may only send

a control voltage to electric motor 310 via an electrical coupling (not shown). In

another embodiment, motor control unit 313 may be implemented as a separate unit which is communicatively coupled with control unit 120 via coupling 115 and

with electric motor 310 via an electrical coupling (not shown).

In embodiments of the present invention, drive wheel 311 is coupled with

steering wheel 330 with sufficient friction such that rotation of drive 311 causes

rotation of steering wheel 330. In embodiments of the present invention, a spring

(not shown) maintains sufficient pressure for coupling drive wheel 311 with

steering wheel 330. However, the spring does not maintain sufficient pressure

between drive wheel 31 1 and steering wheel 330 to pinch a user's fingers if, for

example, the user is manually steering mobile machine 105 and the user's

fingers pass between drive wheel 311 and steering wheel 330. While the

embodiment of Figures 3A and 3B show drive wheel 311 contacting the outside

portion of steering wheel 330, in other embodiments of the present invention,

drive wheel 311 contact the inside portion of steering wheel 330.

In embodiments of the present invention, electric motor 310 is reversable,

thus, depending upon the steering command sent from control component 120,

motor control unit 313 controls the current to electric motor 310 such that it

rotates in a clockwise of counter-clockwise direction. As a result, steering wheel

330 is turned in a clockwise or counter-clockwise direction as well. Typically, the

current running through electric motor 310 is calibrated so that drive wheel 311 is

turning steering wheel 330 without generating excessive torque. This facilitates allowing a user to override electric steering component 131. In embodiments of

the present invention, electric motor 310 may be a permanent magnet brush

direct current (DC) motor, a brushless DC motor, a stepper motor, or an

alternating current (AC) motor.

in embodiments of the present invention, motor control unit 313 can detect

when a user is turning steering wheel 330 in a direction counter to the direction

electric steering component 131 is turning. For example, a shaft encoder (not

shown) may be used to determine which direction shaft 312 is turning. Thus,

when a user turns steering wheel 330 in a direction which counters the direction

electric motor 310 is turning, the shaft encoder detects that the user is turning

steering wheel 330 and generates a signal to motor control unit 313. In response

to determining that a user is turning steering wheel 330, motor control unit 313

can disengage the power supplied to electric motor 310. As a result, electric

motor 310 is now freewheeling and can be more easily operated by the user. In

another embodiment, motor control unit 313 when steering wheel 330 is turned

counter to the direction electric motor is turning, a circuit in motor control unit 313

detects that electric motor 310 is stalling and disengages the power supplied to

electric motor 310. In another embodiment, a switch detects the rotation of

steering wheel 330 and sends a signal to motor control unit 313. Motor control

unit 313 can then determine that the user is manually steering mobile machine

105 and disengage electric motor 310. As a result, when a user turns steering wheel 330, their fingers will not be pinched if they pass between drive wheel 311

and steering wheel 330 because electric motor 310 is freewheeling when the

power is disengaged.

Embodiments of the present invention are advantageous over

conventional vehicle control systems in that it can be easily and quickly installed

as an after market kit. For example, conventional control systems typically

control a vehicle using solenoids and hydraulic flow valves which are coupled

with the power steering mechanism of the vehicle. These systems are more

difficult to install and more expensive than the above described system due to the

higher cost of the solenoids and hydraulic flow valves as well as the additional

labor involved in installing the system. The embodiment of Figure 3 can be easily

bolted onto steering column 340 and coupled with steering controller 220.

Additionally, electric motor 310 can be fitted to a variety of vehicles by simply

exchanging bracket 320 for one configured for a particular vehicle model.

Furthermore, embodiments of the present invention do not rely upon furrow

feelers which typically must be raised from and lowered into a furrow when the

end of the furrow is reached. As a result, less time is lost in raising or lowering

the furrow feeler.

Figures 4A and 4B show side and top views respectively of a system 400

for controlling a mobile machine in accordance with embodiments of the present invention. In Figure 4A, the steering component (e.g., electric steering

component 131 of Figure 2) comprises an electric motor 410 which is coupled

with drive wheel 411 via shaft 412 and a motor control unit 413. Motor control

unit 413 couples electric motor 410 with steering controller 220 of Figure 2. In

Figure 4A, electric motor 410 is with steering column 440 via bracket 420. In the

embodiment of Figures 4A and 4B, drive wheel 411 is coupled with a sub wheel

431 which is coupled with steering wheel 330 via brackets 432.

In the embodiment of Figures 4A and 4B, electric motor 410 turns in a

clockwise or counter-clo.ckwise direction depending upon the steering command

received by motor control unit 413. As a result, drive wheel 411 causes sub

wheel 431 to turn in clockwise or counter clockwise direction as well. Utilizing

sub wheel 431 prevents a user's fingers from being pinched between steering

wheel 430 and drive wheel 411 if the user chooses to manually steer the vehicle.

In embodiments of the present invention, sub wheel 431 can be easily and

quickly coupled with steering wheel 430 by, for example, attaching brackets 432

to the spokes of steering wheel 430.

MOTOR MOUNT EMBODIMENT OF THE PRESENT INVENTION

Figure 6 shows a perspective view of a motor mount assembly 600 in

accordance with embodiments of the present invention. Figure 6 shows a fully

assembled motor mount assembly in which a right side cover 610 and a left side

cover 611 are coupled with an upper motor mount (not shown) using cover

screws (e.g., 613). Right side cover 610 and left side cover 61 1 prevent users

from getting their fingers caught in the mechanism of the motor mount, protect

the drive motor, and present a less cluttered appearance to the user. Extending

from the top of motor mount assembly 600 is a drive wheel 620. In embodiments

of the present invention, drive wheel 620 controls the movement of the steering

wheel of a vehicle in response to steering command from, for example, steering

controller 220. A slot in the side of right side cover 610 permits lower motor

mount 630 to extend outside of the cover when the upper motor mount is moved

with respect to lower motor mount 630.

Figure 7 is an exploded perspective view of a motor mount assembly 600

in accordance with embodiments of the present invention. As shown in Figure 7,

right side cover 610 and left side cover 611 are coupled with upper motor mount

640 using cover screws 613. Drive motor 650 is coupled with upper motor mount

640 using motor mount screws 651. A drive shaft 652 is coupled with motor shaft

653 using shaft screws 654. Drive shaft 652 is coupled with drive wheel 620 using drive wheel screws 621. In embodiments of the present invention, a cap

(not shown) can be inserted into drive wheel 620 to cover drive wheel screws

621.

Figures 8A, 8B, and 8C show perspective, front, and top views

respectively of a lower motor mount 630 in accordance with embodiments of the

present invention. In embodiments of the present invention, lower motor mount

630 comprises a plurality of mounting holes 631. In the present embodiment,

mounting holes 631 have a squared configuration, however in other

embodiments of the present invention, a more conventional rounded

configuration may be implemented. The squared configuration shown in Figures

8A and 8C are advantageous because they facilitate mounting coupling lower

motor mount 630 to, for example, the steering column of a vehicle using only one

wrench. For example, square-necked carriage bolts (not shown) may be inserted

into mounting holes 631 and coupled with a bracket (not shown) to couple lower

motor mount 630 to the steering column of a vehicle. If mounting holes 631 had

a rounded configuration, two wrenches and/or screwdrivers would be needed to

securely mount lower motor mount 630.

Lower motor mount 630 further comprises a bearing hole 632 which is

surrounded by a plurality of bearing mounting holes (e.g., typically shown as

633). Lower motor mount 630 further comprises first positive stop 634 and 635 and latching pin bushing 636. In embodiments of the present invention, first

positive stop 634 and/or second positive stop 635 may be removably coupleable

with lower motor mount 630. For example, first positive stop 634 may comprise a

threaded portion which is screwed into a threaded hole in lower motor mount

630. Finally, lower motor mount 630 comprises a spring mounting hole 637.

Referring now to Figure 8B, which shows a front view of lower motor

mount 630 without first positive stop 634, second positive stop 635, and latch pin

bushing 636 inserted. In embodiments of the present invention, lower motor

mount 630 can be fabricated at a low cost and without requiring specialized

fabricating equipment. For example, lower motor mount 630 may be fabricated

out of sheet metal which is simply cut and folded. Furthermore, there is no

requirement for dimension tolerances for bearing hole 632, bearing mounting

holes 633, spring mounting hole 637, and/or the holes for first positive stop 634,

second positive stop 635, and the hole for latch pin bushing 636. As a result, in

embodiments of the present invention, these holes can be simple drilled or

punched through the metal sheet comprising lower motor mount 630.

Figures 9A, 9B, 9C₁ 9D, and 9E show front, side, bottom, top, and rear

views respectively of an upper motor mount 640 in accordance with

embodiments of the present invention. In the present embodiment, top motor

mount 640 comprises an integrated latching lever 641 , pivot shaft mounting hole 642, and spring mounting hole 643. In embodiments of the present invention,

integrated latching lever 641 is for restricting the range of motion of upper motor

mount 640 when coupled with lower motor mount 630. Integrated latching lever

641 is also for engaging a latching pin inserted into latching pin bushing 636 to

keep a drive wheel of the motor mount assembly (e.g., 620 of Figure 6) away

from a steering wheel when upper motor mount is locked in a disengaged

position. In embodiments of the present invention, a portion of integrated

latching lever 641 is bent to create a lead-in ramp 641a. In embodiments of the

present invention, lead-in ramp 641 a facilitates locking upper motor mount 640 in

a disengaged position.

For example, a spring mounted latching pin is coupled in latch pin housing

636 in embodiments of the present invention. To lock upper motor mount 640 in

a disengaged position, a user can simply rotate upper motor mount 640 relative

to lower motor mount 630 so that lead-in ramp 641 a depresses the spring

mounted latching pin. After upper motor mount 640 has been rotated sufficiently

to disengage drive wheel 620, integrated latching lever is moved to a position

where the latching pin is again able to extend past integrated latching lever 641.

When the user releases upper motor mount 640, pressure exerted by a spring

causes upper motor mount 640 to return to a position where integrated latching

lever 641 engages the latching pin in the cutout region 641 b. In embodiments of the present invention, upper motor mount 640 further

comprises cover mounting brackets 644 (e.g., left side cover bracket 644a and

right side cover bracket 644b). With reference to Figure 9B, embodiments of the

present invention further comprise cover mounting holes 645 which are disposed

in the cover mounting brackets 644. As shown in Figure 9B, cover mounting

holes 645 are disposed in right side cover mounting bracket 644b. Figure 9B

also shows the portion of lead-in ramp 641 a which is bent above the plane of

integrated latching lever 641.

Figure 9C is a bottom view of upper motor mount 640 showing a motor

shaft hole 646 and a plurality of motor mounting holes 647. In embodiments of

the present invention, drive motor 650 is coupled with upper motor mount 640

using motor mount screws 651 which are inserted into motor mounting holes 647.

In embodiments of the present invention, motor mounting holes 647 may be

threaded to mechanically couple drive motor 650 to upper motor mount 640.

Motor shaft hole 646 if for letting mort shaft 653 to pass through upper motor

mount 640.

In embodiments of the present invention, upper motor mount 640 can be

fabricated at a low cost and without requiring specialized fabricating equipment.

For. example, upper motor mount 640 may be fabricated out of sheet metal which

is simply cut and folded. Furthermore, there is no requirement for dimension tolerances for pivot shaft mounting hole 642, spring mounting holes 645, motor

shaft hole 646, or motor mounting holes 647. As a result, in embodiments of the

present invention, these holes can be simple drilled or punched through the metal

sheet comprising upper motor mount 640. However, in embodiments of the

present invention, these hole may be threaded to accept threaded screws.

Figures 10A and 10B show side and front views respectively of a pivot

shaft 1000 in accordance with embodiments of the present invention. In

embodiments of the present invention, pivot shaft 1000 is made of stainless steel

or another material which is not likely to deform significantly during normal usage

of motor mount assembly 600. Furthermore, pivot shaft 1000 typically is not

painted anodized, or otherwise coated with a material. As will be discussed in

detail below, this facilitates greater precision in the fabrication of motor mount

assembly 600 as tolerances for paint build up do not have to be accounted for

during the manufacturing process. However, in embodiments of the present

invention, paint may be deposited on the area typically shown as 1001 around

the circumference of pivot shaft 1000 without significantly affecting the precision

of motor mount assembly 600.

In the embodiment of Figure 10, pivot shaft 1000 comprises a first pin

1010 and a second pin 1020. In embodiments of the present invention, first pin

1010 is inserted into pivot shaft mounting hole 642 of upper motor mount 640 and pivot shaft 1000 is then welded or otherwise coupled with upper motor mount 640

In embodiments of the present invention, second pin 1020 is drilled and threaded

to accept a screw in cap screw hole 1021. Second pin 1020 is then inserted into

a pivot bearing (e.g., pivot bearing 1201 of Figure 12) which has been fit into

bearing hole 632 of lower motor mount 630 and coupled therewith using screws

inserted into bearing mounting holes 633. In embodiments of the present

invention, second pin 1020 defines a point of rotation for upper motor mount 640.

Figures 11 A, 11 B, and 11 C show an exploded perspective, side and rear

views respectively of a pivot shaft 1000 and upper motor mount 640 in

accordance with embodiments of the present invention. As discussed above with

reference to Figure 10, in embodiments of the present invention, pivot shaft 1000

is inserted into pivot shaft mounting hole 642 of upper motor mount 640. In

embodiments of the present invention, pivot shaft 1000 is then coupled with

upper motor mount 640 by, for example, welding or bolting them together.

Figure 12 is an exploded perspective view of upper motor mount 630 and

lower motor mount 640 in accordance with embodiments of the present invention.

In Figure 12, upper motor mount 640 is shown with pivot shaft 1000 already

coupled therewith. Also shown in Figure 12 is pivot bearing 1201 which is

inserted into bearing hole 632 of lower motor mount 630 and coupled therewith

using bearing mounting screws 1202. Also shown in Figure 12 is a washer 1203 and cap screw 1204. During assembly, pivot shaft 1000 is inserted into pivot

bearing 1201 and cap screw 1204 is inserted through washer 1203 and screwed

into cap screw hole 1021 of pivot bearing 1000. As a result, upper motor mount

640 and lower motor mount 630 are coupled while still allowing rotation of upper

motor mount 640 with relation to lower motor mount 630 around the axis defined

by pivot shaft 1000.

Also shown in Figure 12 is latch pin 1205 which is coupled with lower

motor mount 630 using a nut 1206. In embodiments of the present invention,

latch pin 1205 is a spring loaded latch pin which is typically extended in the

direction toward upper motor mount 640 unless it is moved by a user. First

positive stop 634 is shown which is coupled with lower motor mount 630 using

screw 1207 and nut 1208. A spring 1209 is coupled with upper motor mount 640

using a screw 1210 which is screwed into spring mounting hole 643. The other

end of spring 1209 is coupled with lower motor mount 630 using a screw 1211

which is screwed into spring mounting hole 637.

In embodiments of the present invention, there is no requirement for

experienced or specially trained assemblers to assemble motor mount assembly

600. .For example, in embodiments of the present invention, each of the screws

shown in Figure 12 can simply be tightened to a pre-determined amount of

torque. As discussed above with reference to Figure 5, in prior art motor mounts, a well trained assembler was needed to tighten screw 512 enough to allow

rotation of thrust bearing 511 without permitting excessive out of plane

movement. In embodiments of the present invention, out of plane movement is

limited by the design of pivot shaft 1000 and pivot bearing 1201. Thus, there is

no requirement for an assembler with special training or skills to assemble motor

mount assembly 600. As a result, additional savings in the manufacture of motor

mount assembly 600 can be realized. Additionally, because embodiments of the

present invention can more effectively control out of plane movement of driving

wheel 620, more precision in the steering of a vehicle (e.g., 105) is realized.

Figure 13 is a section view of a pivot shaft 660 and pivot bearing 1201 in

accordance with embodiments of the present invention. As shown in Figure 13,

pivot shaft 1000 and pivot bearing 1201 have been coupled as described above

with reference to Figure 12. Thus., cap screw 1204 passes through washer 1203

and is screwed into pivot shaft 1000. Also visible in Figure 13 is the weld (e.g.,

1301 which couples pivot shaft 1000 with lower motor mount 630. As shown in

Figure 13, upper motor mount 640 and lower motor mount 630 are not in direct

contact.

In embodiments of the present invention, pivot shaft 1000 and pivot

bearing 1201 are machined components. As described above, this facilitates

controlling the fit tolerances between pivot shaft 1000 and pivot bearing 1201. For example, in one embodiment, the diametral tolerance for pivot shaft 1000 is

within the diametral tolerance class RC4, shaft 17 as defined by the ANSI B4.1-

1967, R1979 standard with a fit tolerance of H8. Thus, the diametral tolerances

between pivot shaft 1000 and pivot bearing 1201 can be controlled so that out of

plane movement of upper motor mount 640 with respect to lower motor mount

630 is kept within an acceptable limit. This also permits utilizing less precise

tolerances in the fabrication of other components of motor mount assembly 600

because it will not diminish the precision of the fit between upper motor mount

640 and lower motor mount 630. For example, bearing hole 632 does not require

a precise diametral tolerance because the diametral tolerance pivot shaft 1000 is

more closely controlled. Similarly, the diametral tolerance of pivot shaft mounting

hole 642 is not typically considered a critical tolerance because the diametral

tolerance of pivot bearing 1201 is more closely controlled.

As discussed above with reference to Figure 5, the nylon insert of the lock

nut can, over time, become worn so that out.of plane movement of the drive

wheel occurs. In embodiments of the present invention, this can be minimized

due to the materials selected for pivot shaft 1000 and pivot bearing 1201 and the

tolerance between these components while still permitting rotation of upper motor

mount 640 with respect to lower motor mount 630. Figures 14A and 14B are front views of a motor mount assembly 600 used

in accordance with embodiments of the present invention. It is noted that for

clarity, some of the components of motor mount assembly 600 described above

with reference to Figure 12 have been omitted from Figures 14A and 14B. Figure

14A shows upper motor mount 640 in a first position wherein a drive wheel (e.g.,

620 of Figure 6) is engaged with a steering wheel of a vehicle or other mobile

machine. As shown in Figure 14A, integrated latching lever 641 of upper motor

mount 640 is engaged with first positive stop 634. This prevents over-rotation of

upper motor mount 640 with respect to lower motor mount 630 due to the force

exerted by spring 1209 (not shown). It is noted that there is a range of motion for

upper motor mount 640 wherein integrated latching lever 641 can move between

the engaged position shown in Figure 14A and the disengaged position shown in

Figure 14B. This allows driving wheel 620 to be displaced by irregularities in the

shape of the steering wheel or, for example, the user's fingers if they pass

between the steering wheel and driving wheel 620. As a result, the user's fingers

will not be pinched by driving wheel 620 if the user's fingers pass between the

steering wheel and driving wheel 620.

In Figure 14B, upper motor mount 640 has been moved to a second

position in which the drive wheel (e.g., 620 of Figure 6) is disengaged from the

steering wheel of a vehicle or other mobile machine. In Figure 14B, integrated

latching lever 641 is engaged with latch pin 1205. This prevents upper motor mount 640 from disengaging from the second position unless a user releases

upper motor mount 640 by, for example, pulling latch pin 1205. This is

accomplished by moving upper motor mount 640 so that lead-in ramp 641 a rides

over the spring loaded latch pin 1205. When upper motor mount 640 has moved

a sufficient distance, cutout 641b is disposed over spring loaded latch pin 1205,

thus allowing the pin to extend again and upper motor mount 640 in the second

position shown in Figure 14B. Also shown in Figure 14B is second positive stop

635 which prevents upper motor mount 640 from over-rotating in that direction

because second positive stop 635 will contact integrated latching lever 641 and

prevent further rotation.

The preferred embodiment of the present invention, a motor mount

assembly for controlling a mobile machine, is thus described. While the present

invention has been described in particular embodiments, it should be appreciated

that the present invention should not be construed as limited by such

embodiments, but rather construed according to the following claims.

Claims

CLAIMSWhat is claimed is:

1. A motor assembly comprising:

a lower motor mount which is mechanically coupled with a steering column

of a mobile machine;

a drive motor coupled with a drive wheel;

an upper motor mount coupled with said lower motor mount and with said

drive motor, said upper motor mount for maintaining pressure such that said drive

wheel stays in contact with a steering wheel of a mobile machine when said

upper motor mount is in a first position and for keeping said drive wheel away

from said steering wheel when said upper motor mount is locked in a second

position.

2. The motor assembly of Claim 1 further comprising:

a pivot shaft fixedly coupled with said upper motor mount; and

a pivot bearing mechanically coupled with said lower motor mount, and

wherein said pivot bearing rotates around said pivot shaft in a plane when said

upper motor mount is coupled with said lower motor mount and prevents out of

plane movement of said upper motor mount.

3. The motor assembly of Claim 1 wherein said lower motor mount further

comprises:

a latching pin for positively locking said upper motor mount in said second

position.

4. The motor assembly of Claim 3 wherein said latching pin is a spring-

loaded latching pin.

5. The motor assembly of Claim 3 wherein said upper motor mount further

comprises:

a integral latching lever for contacting said latching pin when said upper

motor mount is in said second position.

6. The motor assembly of Claim 1 further comprising:

a spring coupled with said upper motor mount and with said lower motor

mount, said spring for maintaining pressure upon said upper motor mount when

in said first position.

7. The motor assembly of Claim 1 wherein said lower motor mount further

comprises:

a first positive stop and a second positive stop to limit the range of

movement of said upper motor mount.

8. The motor assembly of Claim 1 wherein said motor mount assembly is

operable for a user to move said upper motor mount between said first position

and said second position using either hand.

9. The motor assembly of Claim 1 further comprising:

a cover assembly coupled with upper motor mount.

10. The motor assembly of Claim 1 wherein said drive motor is selected from

the group consisting of a permanent magnet brush direct current (DC) motor, a

brushless DC motor, a stepper motor, and an alternating current (AC) servo

motor.

11. The motor assembly of Claim 10 wherein said motor generates

approximately nineteen ounce/inches of torque per ampere of current.

12. The motor assembly of Claim 1 further comprising:

a detection component for determining when a user is steering said mobile

machine and for initiating disengagement of said drive motor in response to said

determining.

Id'." the motor ^"assembly of Claim 1 wherein said drive motor is

communicatively coupled with a control component, said control component for

conveying a steering command to said drive motor in response to receiving

position data describing the geographic position of said mobile machine.

14. A motor mount comprising :

a lower motor mount which is mechanically coupled with a steering column

of a mobile machine such that said lower motor mount remains fixed with respect

to said steering column when coupled therewith;

an upper motor mount which is coupled with said lower motor mount via a

pivot bearing, said upper motor mount for maintaining pressure upon a drive

wheel in contact with a steering wheel of a mobile machine when said upper

motor mount is in a first position and for keeping said drive wheel away from said

steering wheel when said upper motor mount in a second position; and a positive locking mechanism coupled with said lower motor mount and

with said upper motor mount, said positive locking mechanism for locking said

upper motor mount in a second position wherein drive wheel is disengaged from

said steering wheel.

15. The motor mount of Claim 14 further comprising:

a spring coupled with said upper motor mount and with said lower motor

mount, said spring for maintaining pressure upon said upper motor mount when

in said first position.

16. A motor mount comprising :

a lower motor mount which is mechanically coupled with a steering column

of a mobile machine such that said lower motor mount remains fixed with respect to said steering column when coupled therewith;

an upper motor mount which is coupled with said lower motor mount via a

pivot bearing and a spring, said upper motor mount for maintaining pressure

upon a drive wheel in contact with a steering wheel of a mobile machine when ^•

said upper motor mount is operated in a first position and for keeping said drive

wheel away from said steering wheel when said upper motor mount is operated

in a second position; and

a positive locking mechanism coupled with said lower motor mount and

with said upper motor mount, said positive locking mechanism for locking said

upper motor mount in a second position wherein drive wheel is disengaged from

said steering wheel.

17. The motor mount of Claim 14 or 16 wherein said pivot bearing defines a point of

rotation for said upper motor mount.

18. The motor mount of Claim 14 or 16 wherein said bearing limits out of movement of said upper motor mount with respect to said lower motor mount.

19.' The motor mount of Claim 14 or 16 wherein said positive locking mechanism

comprises a spring loaded latching pin.

20. The motor mount of Claim 19 wherein said upper motor mount further

comprises:

an integrated latching lever which engages said spring loaded latching pin

when said upper motor mount is in said second position.

21. The motor mount of Claim 20 wherein said integrated latching lever further

prevents^" moving said upper motor mount to said first position when engaged with

said spring loaded latching pin.

22. The motor mount of Claim 14 or 16 further comprising:

a first positive stop and a second positive stop to limit the range of

movement of said upper motor mount.

23. The motor mount of Claim 14 or 1 β wherein said motor mount is operable for a

user to move said upper motor mount between said first position and said second

position using either hand.