VEHICLE WHEEL SPEED-BASED DETERMINATION OR ESTIMATION OF A LOAD WEIGHT OF A LOAD CARRIED BY A COMMERCIAL VEHICLE

• US 20160041028A1
• Filed: 08/05/2015
• Published: 02/11/2016
• Est. Priority Date: 08/06/2014
• Status: Active Grant

• Current Assignee: Jungheinrich AG
• Original Assignee: Jungheinrich AG
• Inventors: Hammerl, Robert
• Granted Patent: US 9,658,099 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B66F 9/06 movable, with their loads, on wheels or the like, e.g. fork-lift trucks vehicle aspects B60 - B62; vehicles predominantly for transporting loads and modified to facilitate loading or unloading B60P1/00; low-lift hand trucks for transporting goods B62B3/06
• CPC Class Codes: G01G 19/08 for incorporation in vehicles
• CPC Class Codes: G01G 19/083 lift truck scale
• CPC Class Codes: G01G 19/086 wherein the vehicle mass is dynamically estimated
• CPC Class Codes: G01G 9/00 Methods of, or apparatus for, the determination of weight, not provided for in groups G01G1/00 - G01G7/00

Abstract

A method for determining or estimating a load weight of a load (28) carried by a commercial vehicle, in particular by an industrial truck such as a forklift truck (10), comprises:

• • a) determining a speed ratio between a first speed of at least one first wheel (12) loaded by a load carried in a load carrier (18) of the vehicle and a second speed of at least one second wheel (14) of the operating vehicle (10) which has received the load in the load carrier, which second wheel is less heavily loaded or not loaded by a load carried in the load carrier or is relieved by a load carried in the load carrier;
  • b) determining or estimating the load weight of the carried load (28) on the basis of the determined speed ratio and predetermined reference data.

A commercial vehicle (10) comprising a control system (22) carrying out a method of this kind is also provided.

Claims

1. A method for determining or estimating a load weight of a load (28) carried by a commercial vehicle, in particular by an industrial truck such as a forklift truck (10), comprising:

a) determining a speed ratio between a first speed of at least one first wheel (12) loaded by a load carried in a load carrier (18) of the vehicle and a second speed of at least one second wheel (14) of the operating vehicle (10) which has received the load in the load carrier, which second wheel is less heavily loaded or not loaded by a load carried in the load carrier or is relieved by a load carried in the load carrier;

b) determining or estimating the load weight of the carried load (28) on the basis of the determined speed ratio and predetermined reference data.

2. The method according to claim 1, characterised in that the speed ratio is determined by, when driving the vehicle (10), a number of rotations of the at least one first wheel (12) which occur over a defined distance or in a defined time interval, and a number of rotations of the at least one second wheel (14) which occur when driving the defined distance or in the defined time interval being directly or indirectly measured or determined, in that the speed ratio is determined herefrom, and in that the load weight is determined or estimated from the speed ratio thus determined.

3. The method according to claim 1, characterised in that the speed ratio for a carried load (28) is determined at least once from sensor data comprising speed data and/or rotational speed data of a sensor (24) associated with the first wheel (12), and speed data and/or rotational speed data of a sensor (26) associated with the second wheel (14) in order to determine or estimate the load weight.

4. The method according to claim 3, characterised in that the speed ratio for a carried load is repeatedly or continuously determined from the sensor data in order to repeatedly or continuously determine or estimate the load weight.

5. The method according to claim 1, characterised in that the reference data comprise a load-free reference speed ratio between the at least one first wheel (12) and the at least one second wheel (14) for the vehicle (10) without any carried load at an initial state of the wheels, preferably when the wheels are wear-free.

6. The method according to claim 1, characterised in that the reference data comprise at least one load reference speed ratio between the at least one first wheel (12) and the at least one second wheel (14) for the vehicle (10) having a or a respectively carried defined calibration load at an initial state of the wheels, preferably when the wheels are wear-free.

7. The method according to claim 5, characterised in that the load weight is interpolated using the determined speed ratio from the load-free reference speed ratio and the at least one load reference speed ratio on the basis of the load weight of the calibration load or the respective calibration load and optionally a vehicle weight of the vehicle (10) without any carried load.

8. The method according to claim 1, characterised in that a wear state of the wheels (12, 14) is determined and taken into account when determining or estimating the load weight.

9. The method according to claim 8, characterised in that the wear state of the wheels (12, 14) is determined on the vehicle (10) without any carried load, by a number of rotations of the at least one first wheel which occur when driving the vehicle without any carried load over a defined distance, and a number of rotations of the at least one second wheel which occur when driving the defined distance being directly or indirectly measured or determined, and the respective wear state of the wheels and/or a reference speed ratio between the at least one first wheel and the at least one second wheel for the vehicle without any carried load, taking account of the wear state, and/or speed correction values for the wheels are determined herefrom.

10. The method according to claim 8, characterised in that the reference data on the basis of which the load weight is determined or estimated comprise the wear state or at least one of the wear state, the reference speed ratio and the speed correction values.

11. The method according to claim 10, characterised in that the respective number of rotations or the speed data and/or rotational speed data are compensated with respect to the wear state of the wheels, using the speed correction values, and the speed ratio is determined from compensated speed data or rotational speed data, in order to determine or estimate the load weight.

12. A method for controlling at least one drive unit of a commercial vehicle (10), in particular an industrial truck such as a forklift truck, comprising determining or estimating the load weight of a load (28) carried by the vehicle according to the method according to claim 1.

13. The method according to claim 12, characterised in that the vehicle does not comprise any load sensors which are independent of the determination of the speed ratio in order to determine the load weight of a load carried by the vehicle.

14. The method according to claim 12, characterised in that the vehicle comprises at least one load sensor which is independent of the determination of the speed ratio in order to determine the load weight of a load carried by the vehicle, and in that the load weight is in addition determined or estimated on the basis of the determined speed ratio and is preferably used for checking the plausibility of the load weight determination made using the load sensor.

15. The method according to claim 12, characterised in that vehicle dynamics of the vehicle are configured on the basis of the load weight of a carried load, and/or in that a vehicle profile associated with the load weight is selected from a plurality of vehicle profiles associated with different load weights or load weight ranges.

16. The method according to claim 1, characterised in that the at least one first wheel is a front wheel and the at least one second wheel is a rear wheel (14) of the vehicle.

18. The commercial vehicle according to claim 17, characterised in that the control system (22) is configured or programmed to carry out the method according to claim 1.

19. The commercial vehicle according to claim 18, characterised in that the control system (22) is coupled to at least one sensor or device (30) of the vehicle which responds to optical or electrical or magnetic or electromagnetic markers and/or to a transponder, in order to determine, using the first (24) and the second (26) speed sensor, rotations of the at least one first wheel and the at least second wheel which occur when driving a reference driving distance defined by at least one marker and/or at least one transponder, and to evaluate said rotations when carrying out the method.

17. A commercial vehicle, in particular an industrial truck such as a forklift truck (10), comprising at least one drive unit, at least one load carrier (18) and at least one first wheel (12) loaded by a load (28) carried in the load carrier of the vehicle and at least one second wheel (14) which is less heavily loaded or not loaded by a load carried in the load carrier or is relieved by a load carried in the load carrier, a control system (22) of the vehicle or the drive unit thereof being coupled to at least one first speed sensor (24) associated with the/a first wheel (12) and to at least one second speed sensor (26) associated with the/a second wheel of the vehicle,

characterised in that

the control system is configured or programmed to determine a speed ratio between a first speed of the first wheel (12) detected by the first speed sensor (24) and a second speed of the second wheel (14) detected by the second speed sensor (26), and to determine or estimate herefrom the load weight of a load (28) carried in the load carrier, in order to fulfil at least one function relating to the load weight or taking account of the load weight, in particular a control function.