Electronic control for turf maintenance vehicle

• US 5,394,678 A
• Filed: 05/23/1994
• Issued: 03/07/1995
• Est. Priority Date: 01/03/1992
• Status: Expired due to Term

• Current Assignee: Toro Company (Toro)
• Original Assignee: Toro Company (Toro)
• Inventors: Lonn, Dana R., Wucherpfennig, Fredrick D., Dunford, William M.
• Primary Examiner(s): MELIUS, TERRY L
• Application Number:
  US08/249,098
• Time in Patent Office: 288 Days
• Field of Search: 56/10.2 G, 56/10.2 H, 56/7, 56/17.1, 56/249, 56/294, 56/DIG. 2, 56/DIG. 3, 56/DIG. 10, 56/DIG. 20
• US Class Current: 56/10.20H
• CPC Class Codes: A01D 34/006 Control or measuring arrangements
• CPC Class Codes: A01D 34/475 Driving mechanisms for the cutters A01D34/56
• CPC Class Codes: A01D 34/60 fluid
• CPC Class Codes: A01D 41/1274 for drives
• CPC Class Codes: G06F 11/321 Display for diagnostics, e.g. diagnostic result display, self-test user interface
• CPC Class Codes: Y10S 56/02 Methods

Abstract

The present invention provides for an automated clip control device for maintaining a predetermined clip at varying ground speeds, heights of cut, and other changed conditions. The reel speed of the mower 10 is controlled based upon a feed-back control loop, using as input the ground speed of the mower 10, the actual speed of the reel 48, 50, and 52, the number of blades on the reel, and height of cut, among other factors. A microprocessor 102 uses control process equations to determine the duration of an output pulse width modulated signal which is provided to a valve 702, 706 controlling hydraulic fluid flow to the reel motor 71-75. The target value of the reel speed is determined by reading the desired height of cut value and the number of blades per reel, and then going to a look-up table which contains optimized "linear distance traveled per time grass is cut" values. Once the appropriate look-up table target value is found, the target reel speed is determined by finding the product of the number of blades on the reel times the target clip times the ground speed times a constant (to correct for units).

Claims

1. A control system for controlling the rotational speed of a reel of a turf mower, comprising:

a) first sensing means for determining the rotational speed of the reel and for providing a sensed rotational speed signal;

b) second sensing means for determining the ground speed of the mower and for providing a sensed ground speed signal; and

c) first control means, operatively connected to said first and second sensing means, for receiving said sensed rotational and ground speed signals, for determining a target rotational speed value from said sensed ground speed signal, for comparing said sensed rotational speed with said target rotational speed value, and for determining an output signal from said compared values, wherein said output signal is related to said target rotational speed value, whereby the speed of the reel is controlled to optimize the clip.

2. The system of claim 1, wherein said first control means includes a microprocessor.

3. The system of claim 2, wherein said first control means determines said output signal using a control process algorithm having the following form:

space="preserve" listing-type="equation">u(t)=Error/K.sub.p +Change Error/K.sub.d +Σ

Error/K.sub.1

wherein u(t) is said output signal, and K_p, K_d and K_i are constants.

4. The system of claim 1, further comprising a visual indicator, and wherein said first control means is operatively connected to said visual indicator and activates said visual indicator when said target rotational speed value cannot be maintained, whereby an operator of the turf mower is alerted.

5. The system of claim 2, wherein said first control means further includes memory means for storing data.

6. The system of claim 5:

wherein said memory means stores a control process algorithm used by said first control means for determining said output signal;

further comprising a look-up table stored in said memory means which includes data related to desired clip lengths based on height of cut, number of blades per reel, and ground speed, and

wherein said first control means determines said target rotational speed value from said look-up table.

7. The system of claim 5, further comprising a plurality of switch means for monitoring the status of various turf mower operative conditions, wherein each of said plurality of switch means is cooperatively connected to said first control means to provide the logical status of the monitored operative condition to said first control means, and wherein said first control means qualifies the operative state of the turf mower based upon a logic table stored in said memory means and said monitored operative condition inputs, whereby the turf mower operates only when predetermined operative condition inputs are received.

8. The system of claim 6, further comprising a two way communication port operatively connected to said first control means, wherein said control process algorithm may be modified by a remote computer.

9. The system of claim 5, further comprising a two way communication port, and wherein said first control means provides diagnostic information to said port.

11. The system of claim 9, further including second memory means for storing a rolling record of said diagnostic information.

12. The system of claim 2, wherein said first control means includes a controller area network communications device for communicating and interfacing with second control means on the turf mower.

10. The system of said 9, wherein said diagnostic information includes the status of the operation of said first control means.

13. A reel cutting system for a turf mower comprising:

a) a prime mover;

b) a hydraulic pump energized by said primer mover;

c) a cutting reel operatively rotated by a hydraulic fluid motor;

d) a manifold system for controlling the flow of hydraulic fluid from said hydraulic pump to said hydraulic motor in accordance with control signals; and

e) clip control means comprising;

i) first sensing means for determining the rotational speed of said reel and for providing a sensed rotational speed signal;

ii) second sensing means for determining the ground speed of the turf mower and for providing a sensed ground speed signal; and

iii) first control means, operatively coupled to said first and second sensing means, for receiving said sensed rotational and ground speed signals, for determining a target rotational speed value from said sensed ground speed signal, for comparing said sensed rotational speed with said target rotational speed value, and for calculating an output signal to establish a feedback control loop,

wherein said first control means generates a control signal for said manifold system based on said output signal, and whereby the reel speed is controlled to optimize the clip.

14. The system of claim 13, wherein said first control means includes a microprocessor.

15. The system of claim 13, wherein said feedback control loop includes a control process algorithm having the following form:

space="preserve" listing-type="equation">u(t)=Error/K.sub.p +Change Error/K.sub.4 +Σ

Error/K.sub.i

wherein u(t) is said output signal, and K_p, K_d and K_i are constants.

16. The system of claim 14, further comprising a plurality of valves located in said manifold system and responsive to said control signals, wherein said control signals control said valves to control the flow of hydraulic fluid.

17. The system of claim 14, further comprising a visual indicator, and wherein said first control means is operatively connected to said visual indicator and activates said visual indicator when said target rotational speed value cannot be maintained, whereby an operator of the turf mower is alerted.

18. The system of claim 14, wherein said first control means further includes memory means for storing data.

19. The system of claim 18, wherein said feedback control loop includes a control process algorithm stored in said memory means.

20. The system of claim 18, further comprising a look-up table stored in said memory means which includes data related to desired clip lengths based on height of cut, number of blades per reel, and ground speed;

and

wherein said first control means determines said target rotational speed value from said look-up table.

21. The system of claim 18, further comprising a plurality of switch means for monitoring the status of various turf mower operative conditions,wherein each of said plurality of switch means is cooperatively connected to said first control means to provide the logical status of the monitored operative condition to said first control means, and wherein said first control means qualifies the operative state of the turf mower based upon a logic table stored in said memory means and said monitored operative condition inputs, whereby the turf mower operates only when predetermined operative conditions inputs are received.

22. The system of claim 21, further comprising a plurality of valves located in said manifold system and responsive to said control signals, wherein said control signals control said valves to control the flow of hydraulic fluid, and wherein certain of said valves are not actuated until predetermined operative condition inputs are received.

23. A controller for a grass cutting machine, of the type having a cutting reel driven by a motor system, comprising:

a) memory means for storing a control algorithm for use in a feedback control loop and data;

b) first sensing means for determining the rotational speed of the reel and for providing a sensed rotational speed signal;

c) a plurality of switch means for monitoring the status of various machine operative conditions, wherein each of said plurality of switch means provides the logical status of the monitored operative condition;

d) processor means for;

i) receiving said sensed rotational speed signal and determining an output signal to the motor system to maintain the reel at a desired speed in accordance with said control algorithm and said data wherein said data includes information on the ground speed of the turf mower and wherein the relationship between the desired speed of the reel and the ground speed is non-linear and is determined to optimize the clip; and

ii) qualifying the operative state of the grass cutting machine in accordance with a logical table comprised of said data in said memory means and said monitored operative condition inputs, whereby the turf mower operates only when predetermined operative condition inputs are received.

24. The controller of claim 23, wherein said control algorithm has the following form:

space="preserve" listing-type="equation">u(t)=Error/K.sub.p +Change Error/K.sub.d +Σ

Error/K.sub.i

wherein u(t) is said output signal, and K_p, K_d and K_i are constants.

25. A reel cutting system for a turf mower, comprising:

a) a prime mover;

b) an energy transfer system energized by said prime mover, said system including a motor;

c) a cutting reel operatively rotated by said motor; and

d) clip control means comprising;

i) first sensing means for determining the rotational speed of said reel and for providing a sensed rotational speed signal;

ii) second sensing means for determining the ground speed of the turf mower and for providing a sensed ground speed signal; and

iii) first control means, operatively coupled to said first and second sensing means, for receiving said sensed rotational and ground speed signals, for determining a target rotational speed value from said sensed ground speed signal, for comparing said sensed rotational speed with said target rotational speed value. and for determining an output signal in a feedback loop control,

wherein said first control means applies said output signal to said motor, whereby the rotational speed of said motor, and hence the rotational speed of said reel, are controlled for optimizing the clip.

26. The reel cutting system of claim 25, wherein said system is a hydraulic system and wherein said motor is a hydraulic fluid motor.

27. A method for controlling the rotational speed of a reel of a turf mower, comprising the steps of:

a) determining the rotational speed of the reel and providing a sensed rotational speed signal to a controller device;

b) determining the ground speed of the mower and providing a sensed ground speed signal to said controller device wherein said controller device determines a target rotational speed value from said sensed ground speed signal;

c) comparing said rotational speed of the reel with said target rotational speed value; and

d) determining an output signal from said compared values, wherein said output signal is related to said target rotational speed value of the reel and is used as an output signal in a feedback loop, whereby the speed of the reel is controlled to optimize the clip.

28. The method of claim 27, further comprising the steps of creating a pulse width modulated signal based on said output signal for controlling a motor connected to the reel.

29. The method of claim 27, wherein said control process algorithm of said calculating step has the following form:

space="preserve" listing-type="equation">u(t)=Error/K.sub.p +Change Error/K.sub.d +Σ

Error/K.sub.i

wherein u(t) is said output signal, and K_p, K_d and K_i are constants.

30. The method of claim 27, further comprising the step of activating a visual indicator when said target rotational speed value cannot be maintained, whereby an operator of the turf mower is alerted.