RADIAL FREQUENCY OF CLIP CONTROL SYSTEM

Abstract

A radial frequency of clip control system includes a steering angle sensor for a steerable rear wheel of a grass mowing machine, a pedal sensor for sensing an operator input for a desired ground speed at a reference point adjacent an operator seat on the grass mowing machine; and an electronic controller that uses the desired ground speed and location of each of a plurality of reel cutting units to calculate a rotational speed for each of the plurality of reel cutting units.

Claims

1. A radial frequency of clip control system, comprising: a controller that provides a plurality of different rotational speed commands to a plurality of reel cutting units based on a sensor input for a turning angle of a steerable rear wheel of a grass mowing machine and a calculated distance of each reel cutting unit to an instantaneous turn center of the grass mowing machine.

2. The radial frequency of clip control system of claim 1 wherein each reel cutting unit is rotated by an electric motor.

3. The radial frequency of clip control system of claim 1 wherein the distance to the instantaneous turn center is calculated using a reference point on each reel cutting unit.

4. The radial frequency of clip control system of claim 1 wherein the rotational speed commands to the plurality of reel cutting units provide a specified frequency of clip.

5. A radial frequency of clip control system, comprising the steps of: sensing a steering angle of a steerable rear wheel on a triplex greensmower; sensing a pedal input for a desired speed at a reference point on the triplex greensmower; providing reel rotational speed commands to each of a plurality of reel cutting units, the rotational speed commands being a function of the sensed steering angle, the sensed pedal input, the location of the reference point, and at least one dimension of the triplex greensmower.

6. The radial frequency of clip control system of claim 5 wherein the reference point is adjacent an operator seat on the triplex greensmower.

7. The radial frequency of clip control system of claim 5 wherein at least one dimension of the triplex greensmower is stored in controller memory.

8. A radial frequency of clip control system, comprising: a steering angle sensor for a steerable rear wheel on a grass mowing machine; a pedal sensor for sensing an operator input for a desired ground speed at a reference point adjacent an operator seat on the grass mowing machine; and an electronic controller that uses the desired ground speed and location of each of a plurality of reel cutting units to calculate a rotational speed for each of the plurality of reel cutting units.

9. The radial frequency of clip control system of claim 8 wherein the reference point is located on a centerline of the grass mowing machine.

10. The radial frequency of clip control system of claim 8 further including an electric motor rotating each of the plurality of reel cutting units.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a top view of a triplex greensmower with a radial frequency of clip control system according to a first embodiment.

[0008] FIG. 2 is a schematic diagram of radial frequency of clip control system for a triplex greensmower according to a first embodiment.

DESCRIPTION OF PREFERRED EMBODIMENT

[0009] FIG. 1 shows triplex greensmower 102 having a radial frequency of clip control system that provides the same frequency of clip for a plurality of reel cutting units, when mowing in a straight line and when turning. The triplex greensmower may include left and right front reel cutting units 104 positioned side-by-side forwardly of left and right drive wheels 108, and center or rear reel cutting unit 106 positioned behind the drive wheels and in front of steerable rear wheel 110. An electric motor may drive each cutting reel and may be mounted to one side of each reel cutting unit. The left and right front drive wheels may be driven by electric motors. Optionally, the steerable rear or center wheel also may be driven by an electric motor. While the radial frequency of clip control system is shown on a triplex greensmower, the system also may be used on other grass mowing machines having a plurality of reel cutting units. For example, the radial frequency of clip control system also may be used on fairway mowers having 5 or 7 reel cutting units. There is no limitation of the number of reel cutting units.

[0010] In one embodiment, radial frequency of clip control system 100 may include a sensor input to controller 105 for the angle ?.sub.1 of steerable rear wheel 110. The controller may use angle ?.sub.1 to determine the location of point 0, the instantaneous turn center of the triplex greensmower or other grass mowing machine. In FIG. 2, point 0 is shown as the instantaneous turn center extending from the steerable rear wheel and the front drive wheel axis.

[0011] In one embodiment, radial frequency of clip control system 100 may include a pedal input to the controller for desired ground speed V.sub.veh at reference point VEH. Reference point VEH may be located anywhere on the centerline of a triplex greensmower or other grass mowing machine, rearward of front wheel axis FA. To minimize centrifugal force and improve operator feel, reference point VEH may be located near the operator seat. For example, the grass mowing machine may include a display or input device to the controller, which the operator may use to enter the desired location of VEH, or move the location forward or rearward.

[0012] In one embodiment, the radial frequency of clip control system may include a controller that calculates the ground speed V.sub.FA at the centerline of the front drive wheel axis, based on desired ground speed V.sub.veh at reference point VEH, and angle ?.sub.2 from VEH to point 0. To calculate the ground speed V.sub.FA at the centerline of the front drive wheel axis, the controller may use the equation V.sub.FA=cos (?.sub.2)*V.sub.veh.

[0013] In one embodiment, the radial frequency of clip control system may include a reference point on each of the plurality of reel cutting units. For example, FIG. 2 shows reference points P.sub.L on left front reel cutting unit, P.sub.R on right front reel cutting unit, and P.sub.C on center or rear cutting unit. The controller may store the distance from each reference point to the front drive wheel axis. For example, FIG. 2 shows B.sub.F as the distance from P.sub.L or P.sub.R to front drive wheel axis FA; and B.sub.C as the distance from P.sub.C to front drive wheel axis FA. The controller also may store the distance from each reference point to the grass mowing machine centerline. For example, FIG. 2 shows D.sub.L and D.sub.R as the distance from P.sub.L or P.sub.R to the mower centerline; and P.sub.C is located on the mower centerline. Additionally, the controller may store CM.sub.L as the distance from the front drive wheel axis to the rear steerable wheel axis.

[0014] In one embodiment, the radial frequency of clip control system may include a controller that calculates the distance from the reference point on each reel cutting unit to point 0, the instantaneous turn center. The controller first may calculate R.sub.0, the distance from the mower centerline to point 0, using the equation R.sub.0=CM.sub.L*tan(?.sub.1); A.sub.L, the distance parallel to the front axis from reference point P.sub.L to point 0, using the equation A.sub.L=R.sub.0+D.sub.L; and A.sub.R, the distance parallel to the front axis from reference point P.sub.R to point 0, using the equation A.sub.R=R.sub.0?D.sub.R. The controller then may calculate C.sub.L, the distance from reference point P.sub.L to point 0, using the equation C.sub.L=?{square root over (A.sub.L.sup.2+B.sub.F.sup.2)}, C.sub.R, from reference point P.sub.R to point 0, using the equation C.sub.R==?{square root over (A.sub.R.sup.2+B.sub.F.sup.2)}, and C.sub.C, from reference point P.sub.C to point 0, using the equation C.sub.C==?{square root over (R.sub.O.sup.2+B.sub.R.sup.2)}.

[0015] In one embodiment, the radial frequency of clip control system may include a controller that calculates the rotational speed of each reel cutting unit to maintain the same specified frequency of clip when turning. The rotational speed of each reel cutting unit may be based on the distance from the reference point on each reel cutting unit to point 0, the instantaneous turn center. The controller can adjust the rotational speed of each reel to maintain the desired frequency of clip when turning. For example, the controller may calculate the rotational speed OR of the right front reel cutting unit using the equation ?.sub.R=(C.sub.R/R.sub.0)*(V.sub.FA*1056)/(FOC*#Blades); the rotational speed ?.sub.L of the left front reel cutting unit using the equation ?.sub.L=(C.sub.L/R.sub.0)*(V.sub.FA*1056)/(FOC*#Blades); and the rotational speed ?.sub.C of the center or rear reel cutting unit using the equation ?.sub.C=(C.sub.C/R.sub.0)*(V.sub.FA*1056)/(FOC*#Blades).

[0016] The radial frequency of clip control system includes a controller that provides the same frequency of clip for all reel cutting units, when mowing in a straight line and when turning. The controller commands the speed for each reel cutting unit based on the distance of the reel cutting unit to point 0, the instantaneous turn center of the mower.

[0017] Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.