# US 2020/0399858 A1 · Work machine and method of controlling the same

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- Number: US 2020/0399858 A1
- Document ID: US20200399858A1
- Status: Published application
- Kind: A1
- Application number: 16/971,504
- Filed: 2019-02-26
- Published: 2020-12-24
- Earliest claimed: 2018-04-26
- Assignees: Komatsu Ltd.
- Applicants: Komatsu Ltd.
- Inventors: Shintaro KOBAYASHI; Yuki ARAI; Takeshi KAMIMAE
- Web page: https://patentgrep.com/patent/US20200399858A1

## CPC

- E02F 9/225: {Control of steering, e.g. for hydraulic motors driving the vehicle tracks (steering in general B62D)}
- B60K 17/354: having separate mechanical assemblies for transmitting drive to the front or to the rear wheels or set of wheels
- B60W 30/02: Control of vehicle driving stability
- B62D 6/02: responsive only to vehicle speed
- B62D 9/002: {combined with means for differentially distributing power on the deflectable wheels during cornering}
- B62D 12/00: Steering specially adapted for vehicles operating in tandem or having pivotally connected frames (steering endless tracks or the like B62D11/00; steering specially adapted for trailers B62D13/00)
- E02F 3/7663: {Graders with the scraper blade mounted under a frame supported by wheels, or the like}
- E02F 9/0841: {Articulated frame, i.e. having at least one pivot point between two travelling gear units (tractor-trailer combinations B62D53/00)}
- E02F 9/2289: {Closed circuit}
- B60K 17/356: having fluid or electric motor, for driving one or more wheels
- B60K 17/36: for driving tandem wheels
- B60Y 2200/411: Bulldozers, Graders
- B62D 11/04: by means of separate power sources
- E02F 3/7636: {Graders with the scraper blade mounted under the tractor chassis}
- E02F 3/841: {Devices for controlling and guiding the whole machine, e.g. by feeler elements and reference lines placed exteriorly of the machine (construction of roads E01C19/008)}
- E02F 9/2292: {Systems with two or more pumps}
- E02F 9/2296: {Systems with a variable displacement pump}
- Y02T 10/72: Electric energy management in electromobility
- E02F: DREDGING; SOIL-SHIFTING (winning peat E21C49/00)
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- 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)
- B60Y: INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A controller controls a first drive source and a second drive source based on a rotation speed of a right rear wheel measured by a rotation speed sensor and a rotation speed of a left rear wheel measured by a rotation speed sensor, to thereby independently control a rotation speed of each of a right front wheel and a left front wheel.

## Claims

### Claim 1

A work machine comprising:
a right rear wheel, a left rear wheel, a right front wheel and a left front wheel;
a first sensor that measures a rotation speed of the right rear wheel;
a second sensor that measures a rotation speed of the left rear wheel;
a first drive source that provides driving force to the right front wheel;
a second drive source that provides driving force to the left front wheel; and
a controller that controls the first drive source and the second drive source based on the rotation speed of the right rear wheel measured by the first sensor and the rotation speed of the left rear wheel measured by the second sensor, to thereby independently control a rotation speed of each of the right front wheel and the left front wheel.

### Claim 2 (depends on 1)

The work machine according to claim 1, wherein
the controller calculates a turning radius of rear wheels including the right rear wheel and the left rear wheel based on the rotation speed of the right rear wheel measured by the first sensor and the rotation speed of the left rear wheel measured by the second sensor.

### Claim 3 (depends on 2)

The work machine according to claim 2, further comprising:
a front frame provided with the right front wheel and the left front wheel;
a rear frame provided with the right rear wheel and the left rear wheel and coupled to the front frame; and
an articulation sensor that detects an articulation angle between the front frame and the rear frame, wherein
the controller determines a target front wheel rotation speed of the right front wheel and a target front wheel rotation speed of the left front wheel based on the calculated turning radius of the rear wheels and the articulation angle detected by the articulation sensor.

### Claim 4 (depends on 3)

The work machine according to claim 3, wherein
the controller controls the first drive source so as to attain the target front wheel rotation speed of the right front wheel, and controls the second drive source so as to attain the target front wheel rotation speed of the left front wheel.

### Claim 5 (depends on 1)

The work machine according to claim 1, wherein
the first drive source includes a first motor, and the second drive source includes a second motor.

### Claim 6

A method of controlling a work machine having a right rear wheel, a left rear wheel, a right front wheel and a left front wheel, the method comprising:
measuring a rotation speed of the right rear wheel;
measuring a rotation speed of the left rear wheel; and
independently controlling a rotation speed of each of the right front wheel and the left front wheel based on the measured rotation speed of the right rear wheel and the measured rotation speed of the left rear wheel.