Electronic steering apparatus

• US 8,844,658 B2
• Filed: 06/29/2007
• Issued: 09/30/2014
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Hydro-Gear Limited Partnership
• Original Assignee: Hydro-Gear Limited Partnership
• Inventors: Wyatt, Christopher K., Goetzelmann, Alan D., Fox, Ivan E., Vogel, Andy, Hauser, Raymond
• Primary Examiner(s): Rocca, Joseph M
• Assistant Examiner(s): YEAGLEY, DANIEL S
• Application Number:
  US11/771,559
• Publication Number:
  US 20080018269A1
• Time in Patent Office: 2,650 Days
• Field of Search: 701/41, 180/443, 180/6.2, 180/6.24, 180/6.26, 180/6.28, 180/6.32, 180/6.48
• US Class Current: 180/6.48
• 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. An electronic drive control system for a vehicle having a right side actuator engaged to a first control arm of an associated right side variable drive unit, a left side actuator engaged to a second control arm of an associated 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 actuators;

wherein the controller;

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

determines at least one operational output of the right side drive unit and the left side drive unit based on the received signals;

calculates adjustments to at least one of the right side actuator and the left side actuator; and

adjusts the at least one of the right side actuator to move the first control arm of the right side drive unit and the left side actuator to move the second control arm of the left side drive unit to effectuate the at least one operational output of the right side drive unit and the left side drive unit.

2. 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 a control arm of 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 by moving the control arm of the respective drive unit.

3. A vehicle drive system controller in electrical communication with a right and a left actuator each linked to a control arm of a respective right and left drive unit of a 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 to move the control arm of the right drive unit, based on the calculated speed adjustment for the right drive unit; and

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

4. 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 steering 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 steering 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 steering 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.

5. 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 accelerator 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 the master and the right actuator as the slave if the position of the steering mechanism is right of the center position;

calculating a minimum speed reduction;

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

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

6. A method of controlling a drive system of a vehicle at start up, the drive system having two drive units and two associated actuators, 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 calibration error message to an interface of the vehicle;

running diagnostics if the calibration procedure is complete;

determining whether diagnostics are passed;

storing a diagnostics error message if the diagnostics are not passed and outputting the diagnostics 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 at least one of the actuators is not in the neutral position and outputting the neutral condition error message to the interface.

7. The method of claim 6, further comprising the steps of:

determining whether a brake switch of the vehicle is open;

outputting a first error code if the brake switch is not open;

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

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

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

outputting a third error code if the accelerator is not in the neutral accelerator position;

correcting all error codes; and

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

8. 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 a vehicle, the controller programmed to perform the steps of:

receiving input signals from one or more components of a drive system 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 steering 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 steering 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 steering 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.

9. 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 a 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 accelerator 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 the steering system and the accelerator system of the vehicle; and

setting the slave actuator at the new position.

10. 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;

a first actuator in communication with a first control arm of the first variable drive unit;

a second actuator in communication with a second control arm of the second variable drive unit, wherein the actuators move the control arms to facilitate speed adjustment of the respective variable drive units;

an accelerator of the vehicle;

a steering device of the vehicle; and

an electronic drive control system including;

a plurality of sensors each in communication with one of the first drive unit, the second drive unit, the first actuator, the second actuator, the accelerator, and the steering device; and

a controller in communication with the first and second actuators and the plurality of sensors to facilitate independent adjustment of the variable drive units based on input from at least one of the sensors, wherein the controller is configured to;

receive input signals from the plurality of sensors;

determine at least one operational output of the first variable drive unit and the second variable drive unit based on the received input signals;

calculate adjustments to at least one of the first actuator and the second actuator; and

adjust the at least one of the first actuator to move the first control arm of the first variable drive unit and the second actuator to move the second control arm of the second variable drive unit to effectuate the at least one operational output of the first variable drive unit and the second variable drive unit.