Stability control system

• US 10,392,007 B1
• Filed: 09/18/2017
• Issued: 08/27/2019
• Est. Priority Date: 03/26/2015
• Status: Active Grant

• Current Assignee: Hydro-Gear Limited Partnership
• Original Assignee: Hydro-Gear Limited Partnership
• Inventors: Brown, Alyn G., Lapp, Anthony Joseph
• Primary Examiner(s): Anwari, Maceeh
• Application Number:
  US15/707,869
• Time in Patent Office: 708 Days
• Field of Search: 701 22, 701 41
• CPC Class Codes: A01B 69/00 Steering of agricultural machines or implements; Guiding agricultural machines or implements on a desired track
• CPC Class Codes: B60L 15/2036 Electric differentials, e.g. for supporting steering vehicles
• CPC Class Codes: B60W 30/025 related to comfort of drivers or passengers
• CPC Class Codes: B60W 30/04 related to roll-over prevention
• CPC Class Codes: B62D 11/003 Electric or electronic control systems
• CPC Class Codes: B62D 11/12 using separate change-speed gearings
• CPC Class Codes: B62D 11/24 Endless track steering specially adapted for vehicles having both steerable wheels and endless track
• CPC Class Codes: G01C 21/18 Stabilised platforms, e.g. by gyroscope
• CPC Class Codes: G05D 1/0891 specially adapted for land vehicles
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A drive and control system is provided for use on a zero turn vehicle, and includes first and second hydraulic ground drives independently driving a pair of driven wheels. Each ground drive has an electric actuator to control the output thereof. An operator mechanism generates a drive signal corresponding to a neutral drive position or to one of a plurality of non-neutral drive positions of the operator mechanism, and a steering signal corresponding to a neutral steering position or to one of a plurality of non-neutral steering positions of the operator mechanism. Sensors generate signals corresponding to sensed roll, pitch and yaw parameters. A stability control module includes a processor for receiving the drive and steering signals and for providing output signals to the electric actuators.

Claims

1. A drive and control system for use on a vehicle having a prime mover, the drive and control system comprising:

a first hydraulic ground drive engaged to and independently driving a first driven wheel, and a first electric actuator engaged to the first hydraulic ground drive to control the output thereof;

a second hydraulic ground drive engaged to and independently driving a second driven wheel, and a second electric actuator engaged to the second hydraulic ground drive to control the output thereof;

an operator mechanism disposed on the vehicle and configured to generate a drive signal and a steering signal, wherein;

the drive signal corresponds to a neutral drive position of the operator mechanism or to one of a plurality of non-neutral drive positions of the operator mechanism; and

the steering signal corresponds to a neutral steering position of the operator mechanism or to one of a plurality of non-neutral steering positions of the operator mechanism;

a plurality of sensors disposed on the vehicle and capable of generating sensor signals corresponding to sensed roll parameters, sensed pitch parameters and sensed yaw parameters; and

a stability control module comprising a processor connected to the operator mechanism for receiving the drive signal and the steering signal, the stability control module being connected to and capable of providing output signals to the pair of electric actuators;

wherein the processor is configured to;

(a) load an initial roll parameter, an initial pitch parameter, and an initial yaw parameter;

(b) if the drive signal corresponds to one of the non-neutral drive positions, and if the steering signal corresponds to the neutral steering position, activate a steering correction feature;

(c) if the drive signal corresponds to one of the non-neutral drive positions, perform a roll comparison by comparing at least one of the sensed roll parameters to the initial roll parameter and, in response to a first outcome of the roll comparison, limit power supplied to the pair of hydraulic ground drives, enforce a first predetermined maximum vehicle speed, or provide an audible or visual warning; and

(d) if the drive signal corresponds to one of the non-neutral drive positions, perform a pitch comparison by comparing at least one of the sensed pitch parameters to the initial pitch parameter and, in response to a first outcome of the pitch comparison, limit power supplied to the pair of hydraulic ground drives, enforce a second predetermined maximum vehicle speed or provide an audible or visual warning.

2. The drive and control system of claim 1, wherein the operator mechanism comprises a pair of control sticks, each having a plurality of operative positions, wherein the drive signal and the steering signal are generated based on the operative positions of the pair of control sticks.

3. The drive and control system of claim 2, further comprising a first position sensor communicating the operative position of one of the pair of control sticks to the processor and a second position sensor communicating the operative position of the other of the pair of control sticks to the processor.

4. The drive and control system of claim 3, wherein the processor determines if the drive signal corresponds to the neutral drive position by evaluating the operative position of each control stick and determines if the steering signal corresponds to the neutral steering position by evaluating a differential between the operative positions of the pair of control sticks.

5. The drive and control system of claim 4, wherein the processor may be programmed to select the magnitude of the differential position between the pair of control sticks at which the steering signal corresponds to the neutral steering position.

6. The drive and control system of claim 1, wherein the operator mechanism comprises an accelerator pedal and a steering wheel, wherein the processor determines if the drive signal corresponds to the neutral drive position of the operator mechanism by evaluating the operative position of the accelerator pedal and determines if the steering signal corresponds to the neutral steering position of the operator mechanism by evaluating the rotational position of the steering wheel.

7. The drive and control system of claim 1, wherein the processor is configured to, in response to activation of the steering correction feature:

perform a first heading correction that differentially steers the pair of driven wheels based on one or more of the sensed yaw parameters, but not based on the sensed roll parameters; and

perform a second heading correction that differentially steers the pair of driven wheels based on one or more of the sensed yaw parameters and based on one or more of the sensed roll parameters.

8. The drive and control system of claim 1, wherein the roll comparison compares a difference between the sensed roll parameters and the initial roll parameter to a first preprogrammed threshold related to at least one of the following vehicle design characteristics:

weight of the vehicle, wheelbase of the vehicle or the center of gravity of the vehicle.

9. The drive and control system of claim 1, wherein the pitch comparison compares a difference between the sensed pitch parameters and the initial pitch parameter to a second preprogrammed threshold related to at least one of the following vehicle design characteristics:

weight of the vehicle, wheelbase of the vehicle or the center of gravity of the vehicle.

10. The drive and control system of claim 1, wherein the processor is configured not to activate the steering correction feature if the steering signal corresponds to one of the plurality of non-neutral steering positions.

11. The drive and control system of claim 1, wherein the processor is configured to:

load an expected acceleration and determine an actual acceleration;

generate an acceleration comparison by comparing the expected acceleration to the actual acceleration; and

,

in response to a first outcome of the acceleration comparison, decrease power to at least one of the pair of hydraulic ground drives.

12. The drive and control system of claim 11, wherein the processor is configured to load the expected acceleration based on a measured current draw and at least one of the sensed pitch parameters.

13. The drive and control system of claim 12, further comprising a generator connected to the pair of hydraulic ground drives, and the measured current draw is an electric current supplied from the generator to one or both of the pair of hydraulic ground drives.

14. The drive and control system of claim 11, wherein, in response to a second outcome of the acceleration comparison, wherein the second outcome comprises detecting that the expected acceleration matches the actual acceleration, the processor is configured to maintain or increase power to the at least one of the pair of hydraulic ground drives.

15. The drive and control system of claim 11, wherein the processor is configured to compare the actual acceleration to the expected acceleration after performing the roll comparison and the pitch comparison.

16. The drive and control system of claim 1, wherein the processor may be programmed to include a steering deadband where the steering signal corresponds to the neutral steering position when the operator mechanism is in a plurality of steering positions.

17. The drive and control system of claim 1, wherein the plurality of sensors comprises a multi-axis gyroscope and a multi-axis accelerometer.

18. The drive and control system of claim 17, wherein the gyroscope and the accelerometer are integral with the stability control module.

19. A drive and control system for use on a vehicle having one or more driven wheels, the drive and control system comprising:

a plurality of operator inputs, comprising;

an operator drive input having a neutral drive position and a plurality of non-neutral drive positions; and

an operator steering input having a neutral steering position and a plurality of non-neutral steering positions;

at least one hydraulic ground drive engaged to and driving at least one driven wheel;

a plurality of sensors disposed on the vehicle and capable of generating sensor signals corresponding to sensed roll parameters, sensed pitch parameters, and sensed yaw parameters;

a stability control module comprising a processor connected to the plurality of operator inputs, the stability control module being connected to and capable of providing output signals to the at least one hydraulic ground drive;

wherein the processor is configured to;

(a) determine whether the operator drive input is in one of the non-neutral drive positions;

(b) determine whether the operator steering input is in the neutral steering position;

(c) if the operator drive input is in one of the non-neutral drive positions, and if the operator steering input is in the neutral steering position, activate a steering correction feature;

(d) if the operator drive input is in one of the non-neutral drive positions, perform a roll comparison by comparing at least one of the sensed roll parameters to an initial roll parameter and, in response to a first outcome of the roll comparison, limit power supplied to the at least one hydraulic ground drive, enforce a first predetermined maximum vehicle speed or provide an audible or visual warning; and

(e) if the operator drive input is in one of the non-neutral drive positions, provide a pitch comparison by comparing at least one of the sensed pitch parameters to an initial pitch parameter and, in response to a first outcome of the pitch comparison, limit power supplied to the at least one hydraulic ground drive, enforce a second predetermined maximum vehicle speed or provide an audible or visual warning.

20. A method of operating a vehicle, the vehicle comprising:

a pair of driven wheels, and a drive and control system comprising;

a plurality of operator inputs, comprising an operator drive input having a neutral drive position and a plurality of non-neutral drive positions and an operator steering input having a neutral steering position and a plurality of non-neutral steering positions;

a pair of hydraulic ground drives, each hydraulic ground drive being engaged to and driving at least one of the pair of driven wheels;

a plurality of sensors disposed on the vehicle and capable of generating sensor signals corresponding to sensed roll parameters, sensed pitch parameters, and sensed yaw parameters; and

a stability control module comprising a processor connected to the plurality of operator inputs, the stability control module being connected to and capable of providing output signals to the pair of hydraulic ground drives;

the method comprising, via the processor;

(a) determining whether the operator drive input is in one of the non-neutral drive positions;

(b) determining whether the operator steering input is in the neutral steering position;

(c) if the operator steering input is in the neutral steering position, activating a steering correction feature;

(d) if the operator drive input is in one of the non-neutral drive positions, providing a roll comparison by comparing at least one of the sensed roll parameters to an initial roll parameter and, in response to a first outcome of the roll comparison, limiting power supplied to the pair of hydraulic ground drives or enforcing a first predetermined maximum vehicle speed or providing an audible or visual warning; and

(e) if the operator drive input is in one of the non-neutral drive positions, providing a pitch comparison by comparing at least one of the sensed pitch parameters to an initial pitch parameter and, in response to a first outcome of the pitch comparison, limiting power supplied to the pair of hydraulic ground drives or enforcing a second predetermined maximum vehicle speed or providing an audible or visual warning.

21. The method of claim 20, comprising, in response to activation of the steering correction feature, performing a first heading correction that differentially steers the pair of driven wheels based on one or more of the sensed yaw parameters, but not based on the sensed roll parameters.

22. A drive and control system for use on a vehicle having a prime mover, a pair of driven wheels, and a pair of hydraulic ground drives, each hydraulic ground drive being engaged to and independently driving one of the pair of driven wheels to provide zero turn capability to the vehicle, the drive and control system comprising:

an operator mechanism comprising a pair of control sticks, each having a neutral position and a plurality of operative positions, wherein a separate drive signal is generated by each control stick based on the operative position of the respective control stick;

each drive signal corresponds to a neutral drive position of the corresponding control stick or to one of a plurality of non-neutral drive positions of the corresponding control stick; and

a first position sensor communicating the operative position of one of the pair of control sticks to a first processor and a second position sensor communicating the operative position of the other of the pair of control sticks to the first processor;

wherein each of the pair of control sticks generates a speed input value when in one of the plurality of non-neutral drive positions, the speed input value corresponding to a desired speed of the driven wheel corresponding to the respective control stick;

a plurality of sensors disposed on the vehicle and capable of generating sensor signals corresponding to sensed roll parameters, sensed pitch parameters and sensed yaw parameters; and

a pair of electric actuators, each of the pair of electric actuators engaged to one of the pair of hydraulic ground drives to control the output thereof;

a stability control module comprising a second processor connected to the operator mechanism for receiving each drive signal and a separate steering signal generated by each control stick based on the operative position of the respective control stick, the stability control module being connected to and capable of providing output signals to the pair of electric actuators;

wherein the second processor is configured to;

(a) determine if the steering signal of each control stick corresponds to the neutral drive position or one of the plurality of non-neutral drive positions by evaluating the operative positions of the pair of control sticks;

(b) measure a differential between the operative positions of the pair of control sticks;

(b) if the differential between the operative positions of the pair of control sticks is greater than a first predetermined amount, permit the vehicle to operate in a normal zero turn mode; and

(c) if the differential between the operative position of the pair of control sticks is less than the first predetermined amount, and if the steering signal of each control stick exceeds a first predetermined value, then record and store a yaw value of the vehicle as the desired heading of the vehicle and modulate the steering signal of each control stick using a proportional integral derivative control scheme.