Electronic Steering Apparatus

• US 20080018269A1
• Filed: 06/29/2007
• Published: 01/24/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Hydro-Gear Limited Partnership
• Original Assignee: Hydro-Gear Limited Partnership
• Inventors: Vogel, Andy, Hauser, Raymond, Wyatt, Christopher K., Fox, Ivan E., Goetzelmann, Alan D.
• Granted Patent: US 8,844,658 B2
• Time in Patent Office: Days
• US Class Current: 318/53
• CPC Class Codes: A01D 34/006 Control or measuring arrangements
• CPC Class Codes: A01D 34/64 mounted on a vehicle, e.g. a tractor, or drawn by an animal or a vehicle A01D34/695 takes precedence
• CPC Class Codes: B62D 11/003 Electric or electronic control systems
• CPC Class Codes: B62D 11/04 by means of separate power sources
• CPC Class Codes: B62D 11/06 by means of a single main power source
• CPC Class Codes: B62D 11/18 the additional power supply being supplied hydraulically
• CPC Class Codes: B62D 11/183 Control systems therefor
• CPC Class Codes: B62D 3/02 mechanical
• CPC Class Codes: B62D 5/0418 Electric motor acting on road wheel carriers
• CPC Class Codes: B62D 7/12 with twin-output steering gear
• CPC Class Codes: F02N 11/101 for preventing engine starter actuation or engagement

Abstract

An electronic steering and control apparatus and related control methods for a pair of variable drive units. The variable drive units may be hydrostatic, continuously variable transmissions (CVTs), or other similar devices. The apparatus is shown in use with a vehicle that may include a mowing deck.

Claims

1. A variable drive system for a vehicle, the system comprising:

a first variable drive unit in communication with a first wheel of the vehicle;

a second variable drive unit in communication with a second wheel disposed on an opposing side of the vehicle with respect to the first wheel;

an accelerator of the vehicle;

a steering mechanism of the vehicle; and

an electronic drive control system including;

a plurality of sensors each in communication with one of the first and second drive units, the accelerator, and the steering mechanism; and

a controller in communication with the first and the second variable drive units and the plurality of sensors to facilitate independent adjustment of the drive units based on input from at least one of the sensors.

2. The system of claim 1, further comprising:

a first actuator in communication with the first drive unit and the controller; and

a second actuator in communication with the second drive unit and the controller;

wherein the actuators facilitate speed adjustment of the respective drive units.

3. The system of claim 2, wherein the plurality of sensors further comprises at least one position sensor in communication with each actuator.

4. The system of claim 1, wherein the plurality of sensors includes a speed sensor in communication with one of the drive units to sense an output speed of the respective drive unit.

5. The system of claim 4, wherein the speed sensor is in communication with an output shaft of the respective drive unit.

6. The system of claim 5, wherein the speed sensor is utilized to determine whether the respective drive unit is in a neutral condition.

7. The system of claim 1, wherein one of the plurality of sensors is in communication with the accelerator and senses a change in acceleration.

8. The system of claim 1, wherein one of the plurality of sensors is in communication with the steering mechanism and senses a change in steering.

9. An electronic drive control system for a vehicle having a first variable drive unit, a second variable drive unit, an accelerator, and a steering mechanism, the control system comprising:

a controller in communication with the first and second drive units;

an accelerator sensor in communication with the accelerator and the controller;

a steering sensor in communication with the steering mechanism and the controller; and

a first speed sensor associated with the first drive unit and the controller; and

a second speed sensor associated with the second drive unit and the controller;

wherein the controller receives at least one signal from each of the sensors, calculates at least one operational parameter of either one or both of the first and second drive units based on the at least one signal, and controls at least one of the first and second drive units based on the at least one operational parameter.

10. The control system of claim 9, wherein the controller comprises a processor and associated executable software for processing the at least one signal and generating the at least one operational parameter.

11. The control system of claim 9, wherein the operational parameter comprises a speed of the drive unit.

12. The control system of claim 9, wherein the first speed sensor is in communication with an axle shaft driven by the first drive unit.

13. The control system of claim 9, wherein the second speed sensor is in communication with an axle shaft driven by the second drive unit.

14. The system of claim 9, further comprising:

a first actuator in communication with the first drive unit and the controller; and

a second actuator in communication with the second drive unit and the controller;

wherein the actuators facilitate speed adjustment of the respective drive units.

15. The system of claim 14, further comprising a first position sensor in communication with the first actuator and the controller, and a second position sensor in communication with the second actuator and the controller.

16. An electronic drive control system for a vehicle having a right side variable drive unit, a left side variable drive unit, an accelerator, and a steering mechanism, the control system comprising:

a right speed sensor in electrical communication with the right side drive unit;

a left speed sensor in electrical communication with the left side drive unit;

an accelerator signal device in electrical communication with the accelerator;

a steering signal device in electrical communication with the steering mechanism;

a controller in electrical communication with the right speed sensor, the left speed sensor, the accelerator signal device, the steering signal device, and the right and left side drive units;

wherein the controller receives a signal from the right speed sensor, the left speed sensor, the accelerator signal device, and the steering signal device and calculates at least one operational parameter of the right side drive unit and the left side drive unit based on a control algorithm and adjusts the right side drive unit and the left side drive unit based on the at least one operational parameter.

17. The system of claim 16, wherein the algorithm comprises the steps of:

determining a position of the accelerator based on a signal from the accelerator signal device;

determining a position of the steering mechanism based on a signal from the steering signal device;

adjusting the right side drive unit to reflect the accelerator position if the position of the steering mechanism represents a left turn;

adjusting the left side drive unit to reflect the accelerator position if the position of the steering mechanism represents a right turn;

calculating a new position for the left side drive unit if the position of the steering mechanism represents a left turn;

calculating a new position for the right side drive unit if the position of the steering mechanism represents a right turn;

adjusting the left side drive unit to the calculated new position if the position of the steering mechanism represents a left turn; and

adjusting the right side drive unit to the calculated new position if the position of the steering mechanism represents a right turn.

18. The system of claim 16, wherein the new position of the right side drive unit for a right turn of the vehicle and the left side drive unit for a left turn of the vehicle is calculated by an algorithm comprising the steps of:

determining whether a value correlated to the position of the steering mechanism is less than or equal to a predetermined neutral dead band;

assigning the new position equal to a predetermined set point of the accelerator if the position of the steering mechanism is less than or equal to a predetermined neutral dead band;

determining whether a value correlating to the position of the steering mechanism subtracted by the predetermined neutral dead band is less than or equal to;

(PSW/100)*(100−

NDB)

if the position of the steering mechanism is not less than or equal to a predetermined neutral dead band, wherein PSW is the value correlating to the position of the steering mechanism and NDB is the predetermined neutral dead band;

assigning the new position equal to;

MACP−

{MACP*[AVCSP−

NDB/{(PSW/100)*(100−

NDB)}]}

if the value correlating to the position of the steering mechanism subtracted by the predetermined neutral dead band is less than or equal to;

(PSW/100)*(100−

NDB),

wherein MACP is a current position of the drive unit, AVCSP is the absolute value of the position of the steering mechanism, NDB is the predetermined neutral dead band, and PSW is the value correlating to the position of the steering mechanism; and

assigning the new position equal to;

MACP+{MACP*[1−

{[AVCSP−

NDB−

{(PSW/100)*(100−

NDB)}]/[1−

{(PSW/100)* (100−

NDB)}]}]

if the value correlating to the position of the steering mechanism subtracted by the predetermined neutral dead band is not less than or equal to;

(PSW/100)*(100−

NDB),

wherein MACP is a current position of the drive unit, AVCSP is the absolute value of the position of the steering mechanism, NDB is the predetermined neutral dead band, and PSW is the value correlating to the position of the steering mechanism.

19. A method of controlling a drive system of a vehicle having a pair of drive units each providing independent output to a respective drive wheel of the vehicle, the method comprising the steps of:

generating input signals from a steering system and an accelerator system of the vehicle;

sending the input signals to a processor;

calculating an adjustment for each of the drive units based on the input signals;

sending a control signal based on the calculated adjustment from the processor to each of a pair of actuators each linked to one of the drive units of the vehicle; and

controlling the actuators to adjust the respective drive unit in response to the control signal from the processor.

20. A vehicle drive system controller in electrical communication with a right and a left actuator each linked to a respective right and left drive unit of the vehicle, the controller programmed to perform the steps of:

receiving a steering input signal from a steering system of the vehicle;

receiving an accelerator input signal from an accelerator system of the vehicle;

calculating a speed adjustment for each of the drive units based on the steering and accelerator input signals;

sending a right actuator control signal to the right actuator based on the calculated speed adjustment for the right drive unit; and

sending a left actuator control signal to the left actuator based on the calculated speed adjustment for the left drive unit.

21. A method of controlling a drive system of a vehicle having two drive units to effectuate a turn, the method comprising the steps of:

generating input signals from one or more components of the drive system;

sending the input signals to a processor in electrical communication with a right and a left actuator each linked to a respective right and left drive unit of the vehicle;

determining whether a brake of the vehicle is actuated;

returning the actuators to a neutral position if the brake is actuated;

determining whether an accelerator is in reverse if the brake is not actuated;

setting an accelerator value equal to an accelerator position multiplied by a maximum accelerator rate of speed if the accelerator is in reverse;

determining whether a steering mechanism of the vehicle is right or left of a neutral position;

assigning the right actuator as a master actuator and the left actuator as a slave actuator if the steering mechanism is left of the neutral position;

assigning the left actuator as the master actuator and the right actuator as the slave actuator if the steering mechanism is right of the neutral position;

setting the master actuator equal to the accelerator position;

setting a new position for the slave actuator according to rules as follows;

if SWP)≦

NDB, the new position equals MASP;

if (SWP−

NDB)≦

SE1, the new position equals SE2;

otherwise, the new position equals SE3;

wherein;

SWP=steering wheel position;

NDB=neutral dead band;

MASP=master actuator set point;

SE1=(PSW/100)*(100−

NDB)

PSW=percent steering wheel

SE2=MACP−

{MACP*[AVCSP−

NDB/SE1]}

MACP=master actuator current position

AVCSP=absolute value of current steering wheel position

and SE3=MACP+{MACP*[1−

{[AVCSP−

NDB−

SE1]/[1−

SE1]}]}

wherein the slave actuator is moved to the new position at a slave tire steering acceleration rate of change.

22. A method of controlling a drive system of a vehicle having two drive units to effectuate a turn, the method comprising the steps of:

generating input signals from one or more components of the drive system;

sending the input signals to a processor in electrical communication with a right and a left actuator each linked to a respective right and left drive unit of the vehicle;

reading an operating algorithm;

determining whether a brake of the vehicle is actuated;

returning the actuators to a neutral position if the brake is actuated;

determining whether an accelerator of the vehicle is in a neutral position if the brake is not actuated;

comparing a current position of the accelerator to a previous position of the accelerator;

storing data related to the positions of the accelerator in a memory;

determining a position of a steering mechanism of the vehicle if the position of the accelerator has changed;

denoting the right actuator as a master and the left actuator as a slave if the position of the steering mechanism is left of or at a center position;

denoting the left actuator as a master and the right actuator as a slave if the position of the steering mechanism is right of or at a center position;

calculating a minimum speed reduction;

comparing the calculated minimum speed reduction to an unreduced accelerator angle of the accelerator pedal;

setting the minimum speed reduction to the calculated minimum speed reduction if the calculated minimum speed reduction is less than the unreduced accelerator angle;

setting the minimum speed reduction to the unreduced accelerator angle if the calculated minimum speed reduction is greater than the unreduced accelerator angle;

calculating a speed difference percent; and

reducing the speed of the master actuator with respect to the slave actuator based on the calculated speed difference percent.

23. A method of controlling a drive system of a vehicle at start up, the drive system having two drive units and two associated actuators to effectuate a turn, the method comprising the steps of:

determining whether a calibration procedure is complete when an ignition of the vehicle is placed in a RUN position;

storing a calibration error message if the calibration procedure is not complete and outputting the error message to an interface;

running diagnostics if the calibration procedure is complete;

determining whether diagnostics are passed;

storing a diagnostics error message if diagnostics are not passed and outputting the error message to the interface;

determining whether the actuators are in a neutral position if the diagnostics are passed; and

storing a neutral condition error message if the actuators are not in the neutral position and outputting the error message to the interface.

24. The method of claim 23, further comprising the steps of:

determining whether a brake switch of the vehicle is open;

outputting an error code if the brake switch is not open;

determining whether a power take-off switch of the vehicle is closed;

outputting an error code if the power take-off switch is closed;

determining whether an accelerator of the vehicle is in a neutral position;

outputting an error code if the accelerator is not in neutral; and

enabling input of a plurality of controls of the vehicle when all error codes have been corrected.

25. A method of controlling a drive system at start up of a vehicle having a prime mover, the drive system having two drive units and two associated actuators to effectuate a turn, the method comprising the steps of:

determining whether an ignition of the vehicle is in an OFF position;

killing the prime mover if the ignition is in the OFF position;

determining whether a brake switch of the vehicle is open;

returning the actuators to a neutral position if the brake switch is open;

determining whether a power take-off switch of the vehicle is closed;

determining whether any sensors of the vehicle have inputs of either a predetermined low or a predetermined high voltage if the power take-off switch of the vehicle is not closed;

storing and outputting an error message if any sensors of the vehicle have inputs of either the predetermined low or high voltage; and

killing the prime mover if any sensors of the vehicle have inputs of either the predetermined low or high voltage.

26. The method of claim 25, wherein the predetermined low voltage is approximately 0 volts.

27. The method of claim 25, wherein the predetermined high voltage is approximately 5 volts.

28. A method of controlling a drive system at start up of a vehicle having a prime mover, the drive system having two drive units and two associated actuators to effectuate a turn, the method comprising the steps of:

determining whether an ignition of the vehicle is in an OFF position;

killing the prime mover if the ignition is in the OFF position;

determining whether a brake switch of the vehicle is open;

returning the actuators to a neutral position if the brake switch is open;

determining whether a reverse operating system switch of the vehicle is closed;

determining whether any sensors of the vehicle have inputs of either a predetermined low voltage or a predetermined high voltage if the reverse operating system switch of the vehicle is closed;

storing and outputting an error message if any sensors of the vehicle have inputs of either the predetermined low or high voltage; and

killing the prime mover if any sensors of the vehicle have inputs of either the predetermined low or high voltage.

29. The method of claim 28, wherein the predetermined low voltage is approximately 0 volts.

30. The method of claim 28, wherein the predetermined high voltage is approximately 5 volts.

31. A method of controlling a drive system at start up of a vehicle having a prime mover, the drive system having two drive units and two associated actuators to effectuate a turn, the method comprising the steps of:

determining whether an ignition of the vehicle is in an OFF position;

killing the prime mover if the ignition is in the OFF position;

determining whether a brake switch of the vehicle is open;

returning the actuators to a neutral position if the brake switch is open;

determining whether the vehicle is moving in reverse;

determining whether any sensors of the vehicle have inputs of either a predetermined low voltage or a predetermined high voltage if the vehicle is not moving in reverse;

storing and outputting an error message if any sensors of the vehicle have inputs of either the predetermined low or high voltage; and

killing the prime mover if any sensors of the vehicle have inputs of either the predetermined low or high voltage.

32. The method of claim 31, wherein the predetermined low voltage is approximately 0 volts.

33. The method of claim 31, wherein the predetermined high voltage is approximately 5 volts.

34. An electronic drive control system for a vehicle having a right variable drive unit and a left variable drive unit, the control system including an accelerator, a steering mechanism, a right speed sensor in electrical communication with the right side drive unit, a left speed sensor in electrical communication with the left side drive unit, an accelerator signal device in electrical communication with the accelerator, a steering signal device in electrical communication with the steering mechanism;

and a controller in electrical communication with the right speed sensor, the left speed sensor, the accelerator signal device, the steering signal device, and the right and left side drive units, the controller programmed to perform control steps comprising;

receiving a signal from the right speed sensor, the left speed sensor, the accelerator signal device, and the steering signal device;

calculating at least one operational parameter of the right side drive unit and the left side drive unit based on a control algorithm; and

adjusting the right side drive unit and the left side drive unit based on the at least one operational parameter.

35. A vehicle drive system controller in electrical communication with a right and a left actuator each linked to a respective right and left drive unit of the vehicle, the controller programmed to perform the steps of:

receiving input signals from one or more components of the drive system;

determining whether a brake of the vehicle is actuated;

returning the actuators to a neutral position if the brake is actuated;

determining whether an accelerator is in reverse if the brake is not actuated;

setting an accelerator value equal to an accelerator position multiplied by a maximum accelerator rate of speed if the accelerator is in reverse;

determining whether a steering mechanism of the vehicle is right or left of a neutral position;

assigning the right actuator as a master actuator and the left actuator as a slave actuator if the steering mechanism is left of the neutral position;

assigning the left actuator as the master actuator and the right actuator as the slave actuator if the steering mechanism is right of the neutral position;

setting the master actuator equal to the accelerator position;

setting a new position for the slave actuator according to the following rules;

if SWP≦

NDB, the new position equals MASP;

if (SWP−

NDB)≦

SE1, the new position equals SE2;

otherwise, the new position equals SE3;

wherein;

SWP=steering wheel position;

NDB=neutral dead band;

MASP=master actuator set point;

SE1=(PSW/100)*(100−

NDB)

PSW=percent steering wheel

SE2=MACP−

{MACP*[AVCSP−

NDB/SE1]}

MACP=master actuator current position

AVCSP=absolute value of current steering wheel position

and SE3=MACP+{MACP*[1−

{[AVCSP−

NDB−

SE1]/[1−

SE1]}]}

wherein the slave actuator is moved to the new position at a slave tire steering acceleration rate of change.

36. A vehicle drive system controller in electrical communication with a right and a left actuator each linked to a respective right and left drive unit of the vehicle, the controller programmed to perform the steps of:

receiving input signals from a steering system and an accelerator system of the vehicle;

determining a position of an accelerator of the acceleration system;

determining whether a steering mechanism of the steering system is right or left of a neutral position;

assigning the right actuator as a master actuator and the left actuator as a slave actuator if the steering mechanism is left of the neutral position;

assigning the left actuator as the master actuator and the right actuator as the slave actuator if the steering mechanism is right of the neutral position;

setting the master actuator equal to the accelerator position;

calculating a new position for the slave actuator based on the input signals from a steering system and an accelerator system of the vehicle; and

setting the slave actuator at the new position.