# US 11,029,690 B2 · Steering controller for an autonomous vehicle with stability regulation

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- Number: US 11,029,690 B2
- Document ID: US11029690B2
- Status: Granted
- Kind: B2
- Application number: 16/248,830
- Filed: 2019-01-16
- Published: 2019-07-18
- Granted: 2021-06-08
- Earliest claimed: 2018-01-17
- Assignees: AGCO International GmbH
- Applicants: AGCO International GmbH
- Inventors: Christian Noess
- Web page: https://patentgrep.com/patent/US11029690B2

## CPC

- G05D 1/0212: {with means for defining a desired trajectory (involving a plurality of land vehicles G05D1/0287)}
- A01B 69/008: {automatic}
- B62D 1/283: {for unmanned vehicles}
- B62D 11/003: {Electric or electronic control systems}
- B62D 11/04: by means of separate power sources
- B62D 15/025: {Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence)}
- G05D 1/00: Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots (drive control systems specially adapted for autonomous road vehicles B60W60/00)
- G05D 1/0276: {using signals provided by a source external to the vehicle (involving a plurality of vehicles G05D1/0287; automatically controlling vehicle speed responsive to externally generated signals B60K31/0058)}
- G05D 1/646: Following a predefined trajectory, e.g. a line marked on the floor or a flight path
- G05D 1/65: Following a desired speed profile
- G06F 16/29: Geographical information databases
- G05D 2101/10: using artificial intelligence [AI] techniques
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- A01B: SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL (making or covering furrows or holes for sowing, planting or manuring A01C5/00; mowers convertible to soil working apparatus or capable of soil working A01D42/04; mowers combined with soil working implements A01D43/12; soil working for engineering purposes E01, E02, E21)
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A mobile machine including a chassis, a plurality of ground-engaging elements, actuators for driving movement of the ground-engaging elements and a controller for controlling each of the actuators to cause the mobile machine to follow a reference path. The controller is configured to implement a cascading control loop for controlling movement of the mobile machine, the cascading control loop including an outer loop and an inner loop. The outer loop is configured to determine a set heading for reducing a distance between the mobile machine and the reference path, the set heading being determined using an error slope parameter. The inner loop is configured to drive the actuators so that the mobile machine follows the set heading determined by the outer loop. The controller is configured to automatically adjust the error slope value so that the rate of change of the set heading does not exceed a maximum yaw rate.

## Claims

### Claim 1

A mobile machine comprising:
a chassis;
a plurality of ground-engaging elements for supporting the chassis on a ground surface and propelling the chassis relative to the ground surface, each of the plurality of ground-engaging elements being at a fixed angle relative to the chassis;
a plurality of actuators for driving movement of the ground-engaging elements, each of the actuators being configured to drive movement of at least one of the ground-engaging elements independently of the other ground-engaging elements; and
a controller for controlling each of the actuators to cause the mobile machine to follow a reference path, the controller configured to—
implement a cascading control loop for controlling movement of the mobile machine, the cascading control loop including—
an outer loop configured to determine a set heading for reducing a distance between the mobile machine and the reference path, the set heading being determined using an error slope parameter, the set heading causing the mobile machine to follow a path with varying radii of curvature, including a portion of the path with a smallest radius of curvature, and
an inner loop configured to drive the actuators so that the mobile machine follows the set heading determined by the outer loop, and
automatically adjust the error slope parameter so that the rate of change of the set heading does not exceed the mobile machine's maximum yaw rate and, after the mobile machine has traversed the portion of the path with the smallest radius of curvature, the set heading change is the lesser of the maximum error slope and the mobile machine's maximum yaw rate as the mobile machine approaches the reference path.

### Claim 2 (depends on 1)

The mobile machine as set forth in claim 1, the controller further configured to determine the set heading using only a heading reference value and a distance d of the mobile machine from the reference path.

### Claim 3 (depends on 2)

The mobile machine as set forth in claim 2, the controller further configured to determine the set heading by applying a hyperbolic tangent function to the product of the distance d and the error slope parameter.

### Claim 4 (depends on 1)

The mobile machine as set forth in claim 1, the error slope parameter determining an angle at which the mobile machine approaches the reference path and a turn radius of the mobile machine as it approaches the reference path.

### Claim 5 (depends on 1)

The mobile machine as set forth in claim 1, the controller configured to use a maximum yaw rate of the mobile machine and a current velocity of the mobile machine to automatically adjust the error slope value so that the rate of change of the set heading does not exceed the maximum yaw rate.