# US 2021/0240188 A1 · Steering of Forklift Trucks > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0240188 A1 - Document ID: US20210240188A1 - Status: Published application - Kind: A1 - Application number: 17/268,534 - Filed: 2019-08-26 - Published: 2021-08-05 - Earliest claimed: 2018-09-03 - Assignees: Mitsubishi Logisnext Europe Oy - Applicants: Mitsubishi Logisnext Europe Oy - Inventors: Janne LAAKSONEN; Eero PUOLATIE - Web page: https://patentgrep.com/patent/US20210240188A1 ## CPC - B62D 11/003: {Electric or electronic control systems} - G05D 1/646: Following a predefined trajectory, e.g. a line marked on the floor or a flight path - B62D 11/04: by means of separate power sources - B62D 11/24: Endless track steering specially adapted for vehicles having both steerable wheels and endless track - B66F 9/0755: {Position control; Position detectors} - B66F 9/07568: {Steering arrangements} - B66F 9/07572: {Propulsion arrangements} - 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) - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - B66F: HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD ({invalid lifting devices A61G7/10; } mounting artificial islands on piles or like supports E02B17/00; scaffolding combined with lifting devices E04G1/22; lifting devices for sliding forms E04G11/24; lifting of buildings E04G23/06; shores or struts E04G25/00; lifts or other hoisting devices on ladders E06C7/12; props for mining E21D15/00) ## Abstract The invention relates to a method for controlling a motion of a counter balance forklift truck, the method comprises: detecting that a steering command generated with an endless rotating steering device corresponds to a reference steering point, in response to the detection providing at least two states for selecting a travel direction of the counter balance truck, detecting a selected state in accordance with a detection of a change in a steering command, and generating control signals individually to a plurality of electric drive motors for controlling the motion of the counter balance truck to meet the travel direction selected with the steering device. The invention also relates to a forklift truck implementing the method and to a computer program product. ## Claims ### Claim 1 A method for controlling a motion of a counter balance forklift truck, the method comprises: detecting that a steering command generated with an endless rotating steering device corresponds to a reference steering point, in response to the detection providing, by a control unit, at least two states for selecting a travel direction of the counter balance forklift truck, detecting a selected state among the at least two states in accordance with a detection of a change in a steering command generated with the endless rotating steering device of the counter balance forklift truck, and generating control signals, by the control unit, individually to a plurality of electric drive motors of the counter balance forklift truck, each of the plurality of the electric drive motors configured to generate a driving force to at least one driving wheel, for controlling the motion of the counter balance forklift truck to meet the travel direction selected with the steering device. ### Claim 2 (depends on 1) The method of claim 1, wherein a detection that the steering command generated by the endless rotating steering device corresponds to the reference steering point is performed by comparing data included in the steering command to data defining the reference steering point. ### Claim 3 (depends on 2) The method of claim 2, wherein the data included in the steering command comprises at least one of the following: data representing an absolute position of the steering device, data representing a steering motion of the steering device. ### Claim 4 (depends on 3) The method of claim 3, wherein the data representing the absolute position of the steering device is a turning angle of the steering device. ### Claim 5 (depends on 3) The method of claim 3, wherein the data representing the steering motion of the steering device is a rotation direction and speed of the steering device. ### Claim 6 (depends on 1) The method of claim 1, wherein the reference steering point is determined to correspond to at least one of the following situation: a steered wheel in a single steered wheel truck implementation is detected to be steered transversely to the travel direction; a plurality of steered wheels in a plural steered wheel truck implementation is detected to be steered to a position matching with a circumference with respect to a centre of rotation of the counter balance forklift truck. ### Claim 7 (depends on 1) The method of claim 1, wherein in response to the detection that the travel direction is to be changed due to the selected state, the generation of the control signals individually to the plurality of the electric drive motors is performed so that a sum of a speed of a plurality of driving wheels is maintained so that a travel speed of the counter balance forklift truck and a turning peripheral speed of the counter balance forklift truck are equal matching to a set speed for the counter balance forklift truck. ### Claim 8 A counter balance forklift truck, the counter balance forklift truck comprising: at least one control unit, an endless rotating steering device generating steering command to at least one steered wheel, a plurality of electric drive motors of the counter balance forklift truck, each of the plurality of the electric drive motors configured to generate a driving force to at least one driving wheel, the control unit is configured to: detect that a steering command generated with the endless rotating steering device corresponds to a reference steering point, provide, in response to the detection, at least two states for selecting a travel direction of the counter balance forklift truck, detect a selected state among the at least two states in accordance with a detection of a change in a steering command generated with the endless rotating steering device of the counter balance forklift truck, and generate control signals individually to the plurality of electric drive motors of the counter balance forklift truck for controlling the motion of the counter balance forklift truck to meet the travel direction selected with the steering device. ### Claim 9 (depends on 8) The counter balance forklift truck of claim 8, wherein the at least one steered wheel is arranged to be endlessly rotating. ### Claim 10 (depends on 8) The counter balance forklift truck of claim 8, the counter balance forklift truck further comprising at least one sensor configured to obtain measurement data representing a turning angle of the endless rotating steered wheel. ### Claim 11 A computer program product for controlling a motion of a counter balance forklift truck which, when executed by at least one processor of a control unit of the counter balance forklift truck, cause the control unit of the counter balance forklift truck to perform: detecting that a steering command generated with an endless rotating steering device corresponds to a reference steering point, in response to the detection providing, by a control unit, at least two states for selecting a travel direction of the counter balance forklift truck, detecting a selected state among the at least two states in accordance with a detection of a change in a steering command generated with the endless rotating steering device of the counter balance forklift truck, and generating control signals, by the control unit, individually to a plurality of electric drive motors of the counter balance forklift truck, each of the plurality of the electric drive motors configured to generate a driving force to at least one driving wheel, for controlling the motion of the counter balance forklift truck to meet the travel direction selected with the steering device.