Electronically Controlled Speed Limiting System For Turf Care Machine

Abstract

An electronically controlled speed limiting system for a turf maintenance machine includes at least one traction motor rotating a wheel. At least one hydraulic pump in fluid communication with the traction motor provides hydraulic fluid to operate the traction motor. At least one actuator in fluid communication with the hydraulic pump varies an output of the hydraulic pump. A controller in communication with the actuator commands the actuator to control the output of the hydraulic pump and thereby an operating speed of the wheel. A brake is activated by the controller if a wheel speed sensor signals the wheel is slip-spinning, to mitigate turf damage. A steering position sensor signal is used by the controller to modify brake activation during machine turns. An inclinometer signal is used by the controller to automatically reduce machine speed on inclined surfaces.

What is claimed is: 
     
         1 . An electronically controlled speed limiting system for a turf maintenance machine, comprising:
 a first traction motor directly rotating a first wheel and a second traction motor directly rotating a second wheel;   first and second wheel speed sensors individually connected to each of the first and second wheels, each outputting an actual wheel speed signal; and   a controller in communication with the first and second traction motors receiving the actual wheel speed signal from the first and second wheels and an incline signal, operating to compare the actual wheel speed of the first and second wheels to determine if one of the wheels is rotating faster than the other wheel, and generate a command output from the controller in accordance with the incline signal to the faster rotating one of the wheels operates to reduce the actual speed of the faster moving one of the wheels to equal the actual speed of the other of the wheels.   
     
     
         2 . The electronically controlled speed limiting system of  claim 1 , further including at least one hydraulic pump in direct fluid communication with the at least one traction motor providing hydraulic fluid to operate the first and second traction motors. 
     
     
         3 . The electronically controlled speed limiting system of  claim 2 , further including at least one actuator in fluid communication with the at least one hydraulic pump operating to vary an output of the at least one hydraulic pump. 
     
     
         4 . The electronically controlled speed limiting system of  claim 3 , further including a steering position sensor outputting a steering sensor signal which is based on a steering position angle of rotation of a steering wheel, the steering sensor signal being compared in a lookup table saved in the controller to the actual wheel speed signals from the wheel speed sensors, and when an actual speed of one of the first and second wheels exceeds a predetermined speed found in the lookup table for an anticipated wheel speed during a vehicle turn based on the steering sensor signal, a traction control signal is forwarded by the controller to one of the first and second traction motors to thereby decrease an operating speed of the first or second wheel which is slipping. 
     
     
         5 . The electronically controlled speed limiting system of  claim 2  further including a first brake operating to resist rotation of the first wheel and a second brake operating to resist rotation of the second wheel, actuation of one or both of the first and second brakes controlled by a brake signal from the controller. 
     
     
         6 . The electronically controlled speed limiting system of  claim 5 , wherein the brake signal is sent from the controller to the first or second traction motor for the faster rotating one of the wheels to reduce an operating speed of the first or second traction motor for the faster rotating one of the wheels. 
     
     
         7 . The electronically controlled speed limiting system of  claim 1 , further including a lookup table saved in the controller having recommended operating speeds for a plurality of different inclination angles of the turf maintenance machine. 
     
     
         8 . The electronically controlled speed limiting system of  claim 7 , further including an inclinometer operating to sense an angle of inclination of the turf maintenance machine and create an inclinometer signal corresponding to the angle of inclination;
 wherein the inclinometer signal is compared in the controller to the plurality of preset inclination angles in the lookup table, and a speed reduction command is generated by the controller used to reduce an operating speed of the turf maintenance machine to the one of the recommended operating speeds corresponding to the angle of inclination.   
     
     
         9 . An electronically controlled speed limiting system for a turf maintenance machine, comprising:
 at least one traction motor rotating at least one wheel;   at least one hydraulic pump in fluid communication with the at least one traction motor providing hydraulic fluid to operate the at least one traction motor;   at least one actuator in fluid communication with the at least one hydraulic pump operating to vary an output of the at least one hydraulic pump; and   a controller in communication with the at least one actuator providing input and receiving an incline signal, the controller commands to the at least one actuator to control the output of the at least one hydraulic pump and thereby an operating speed of the at least one wheel.   
     
     
         10 . The electronically controlled speed limiting system of  claim 9 , wherein the at least one traction motor includes first and second traction motors and wherein the at least one wheel includes first and second wheels, the first traction motor driving the first wheel and the second traction motor driving the second wheel. 
     
     
         11 . The electronically controlled speed limiting system of  claim 10 , further including first and second wheel speed sensors, the first wheel speed sensor sensing an operating speed of the first wheel and the second wheel speed sensor sensing an operating speed of the second wheel. 
     
     
         12 . The electronically controlled speed limiting system of  claim 11 , further including a wheel speed signal received from each of the first and second wheel speed sensors, the controller operating to compare the wheel speed signals to determine if the first or second wheel is slipping, indicated when the first or second wheel is rotating faster than the other wheel, and output a traction control signal to apply a brake for the faster rotating wheel to equalize the wheel speed of the first and second wheels. 
     
     
         13 . The electronically controlled speed limiting system of  claim 10 , wherein the at least one hydraulic pump includes first and second hydraulic pumps, each in communication with and operating one of the first and second traction motors. 
     
     
         14 . The electronically controlled speed limiting system of  claim 13 , wherein the at least one actuator includes first and second actuators, the first actuator in communication with the first hydraulic pump and the second actuator in communication with the second hydraulic pump. 
     
     
         15 . The electronically controlled speed limiting system of  claim 9 , further including a user interface in communication with the controller for inputting operating commands to be stored in the controller, the operating commands capable of being locked by a user determined password to prevent machine operator modification. 
     
     
         16 . The electronically controlled speed limiting system of  claim 9 , further including a wheel speed sensor measuring an actual speed of the at least one wheel, an output signal from the wheel speed sensor communicated to the controller, the controller operating to compare the actual speed of the first wheel to a desired speed of the first wheel and to output a signal to the at least one actuator to automatically modify the output of the at least one hydraulic pump and thereby the operating speed of the at least one traction motor to match the actual speed to the desired speed. 
     
     
         17 . The electronically controlled speed limiting system of  claim 10 , further including a flow divider positioned between the at least one hydraulic pump and the first and second traction motors, the flow divider in communication with the controller such that a signal to the flow divider from the controller varies a flow rate of hydraulic fluid to each of the first and second traction motors. 
     
     
         18 . An electronically controlled speed limiting system for a turf maintenance machine, comprising:
 a first traction motor rotatably connected to a first wheel and a second traction motor rotatably connected to a second wheel;   a hydraulic pump in fluid communication with both the first and second traction motors providing hydraulic fluid to operate the first and second traction motors;   an actuator in communication with the hydraulic pump operating to vary an output of the hydraulic pump;   a controller in communication with the actuator automatically providing input commands to the actuator to control the output of the hydraulic pump and thereby an operating speed of the first and second wheels based on one or more signals received by the controller wherein one signal works in accordance with an incline of the vehicle; and   a first wheel speed sensor in communication with the first wheel and a second wheel sensor in communication with the second wheel, output signals from the first and second wheel speed sensors supplied to the controller and used by the controller to output a traction control signal to one of the first or second traction motors when the first or second wheel is rotating faster than the other wheel.   
     
     
         19 . The electronically controlled speed limiting system of  claim 18 , further including a steering position sensor outputting a steering sensor signal based on a steering position angle of rotation of a machine steering wheel. 
     
     
         20 . The electronically controlled speed limiting system of  claim 19 , wherein the steering sensor signal is compared in a lookup table saved in the controller to the actual wheel speed signals from the wheel speed sensors, and when an actual speed of one of the first and second wheels exceeds a predetermined speed found in the lookup table for an anticipated wheel speed during a vehicle turn, a traction control signal generated by the controller is forwarded to one of the first and second traction motors to thereby decrease an operating speed of the first or second wheel which is slipping.