METHOD TO DETERMINE A SPEED PROFILE FOR A STAIRLIFT

Abstract

Embodiments described herein are directed to a method to determine a speed profile for a stairlift, wherein the stairlift includes a guide device, a carriage, and user interaction device. The carriage is rotatable around a vertical axle by a first drive. A specific mass moment of inertia for a specific person is determined by measuring a correlation between applied torque and resulting rotational acceleration for the first drive or the specific mass moment of inertia for a specific person is determined by measuring the specific persons weight while the specific person is carried on the carriage. An optimal torque is set according to the specific mass moment of inertia. The speed profile is determined applying at the most the optimal torque with the first drive.

Claims

1. A method to determine a speed profile for a stairlift for transporting a person along a staircase, wherein the stairlift comprises a guide extending along the staircase; a carriage being moveable along the guide and configured to carry the person; a user interaction device configured for operating the stairlift; and a control unit configured to measure a correlation between applied torque and resulting rotational acceleration for a first drive; wherein the carriage is rotatable around a vertical axle by the first drive; wherein the method comprises the steps of: determining a specific mass moment of inertia for a specific person by measuring the correlation between applied torque and resulting rotational acceleration for the first drive with the specific person carried on the carriage; setting an optimal torque according to the specific mass moment of inertia; and determining the speed profile applying at the most the optimal torque with the first drive.

2. The method according to claim 1, wherein the correlation between applied torque and resulting rotational acceleration is measured in a test rotation, wherein the test rotation is conducted once during installation of the stairlift.

3. The method according to claim 1, wherein the speed profile is determined applying not more than an optimal rotational speed for the first drive.

4. The method according to claim 1, wherein the speed profile is determined with information on a trajectory of the guide, wherein the trajectory comprises at least one change of direction around a vertical axle and/or at least one change of direction around a horizontal axle.

5. The method according to claim 1, wherein: the speed profile is determined with information on a necessary angle of rotation around the vertical axle of at least one position of the carriage along the guide, wherein a necessary angle of rotation is set by rotating the carriage manually for at least one position of the carriage along the guide during a test run of the carriage along the guide.

6. The method according to claim 1, wherein the stairlift further comprises: a leveling mechanism for keeping the carriage in a horizontal orientation, and wherein the speed profile is determined with information on an angle of the leveling mechanism of at least one position of the carriage along the guide.

7. A method to determine a speed profile for a stairlift for transporting a person along a staircase, wherein the stairlift comprises a guide extending along the staircase; a carriage being moveable along the guide and configured to carry the person; user interaction device configured for operating the stairlift; and a weight sensor configured to measure a specific persons weight while the specific person is carried on the carriage; wherein the carriage is rotatable around a vertical axle by a first drive; wherein the method comprises the steps of: determining a specific mass moment of inertia for the specific person by measuring the specific persons weight while the specific person is carried on the carriage with the weight sensor; setting an optimal torque according to the specific mass moment of inertia; and determining the speed profile applying at the most the optimal torque with the first drive.

8. The method according to claim 7, wherein the correlation between applied torque and resulting rotational acceleration is measured in a test rotation, wherein the test rotation is conducted once during installation of the stairlift.

9. The method according to claim 8, wherein the test rotation is conducted before a ride.

10. The method according to claim 8, wherein the test rotation is conducted in a landing position of the carriage.

11. The method according to claim 7, wherein the speed profile is determined applying not more than an optimal rotational speed for the first drive.

12. The method according to claim 7, wherein the speed profile is determined with information on a trajectory of the guide.

13. The method according to claim 12, wherein the trajectory comprises at least one change of direction around a vertical axle and/or at least one change of direction around a horizontal axle.

14. The method according to claim 7, wherein the speed profile is determined with information on a necessary angle of rotation around the vertical axle of at least one position of the carriage along the guide.

15. The method according to claim 14, wherein a necessary angle of rotation is set by rotating the carriage manually for at least one position of the carriage along the guide during a test run of the carriage along the guide.

16. The method according to claim 7, wherein the stairlift further comprises: a leveling mechanism for keeping the carriage in a horizontal orientation, and wherein the speed profile is determined with information on an angle of the leveling mechanism of at least one position of the carriage along the guide.

17. The method according to claim 16, wherein the angle of the leveling mechanism is set for at least one position of the carriage along the guide during a test run of the carriage along the guide.

18. The method according to claim 7, wherein the speed profile is optimized for shortest travel time.

19. A stairlift for transporting a person along a staircase, comprising: a guide extending along the staircase; a carriage being moveable along the guide and configured to carry the person; and user interaction device configured for operating the stairlift; wherein the carriage is rotatable around a vertical axle by a first drive, wherein the stairlift further includes a control unit configured to measure a correlation between applied torque and resulting rotational acceleration for the first drive and/or a weight sensor to measure the specific persons weight while the specific person is carried on the carriage.

20. The stairlift according to claim 19, further comprising: a leveling mechanism for keeping the carriage in a horizontal orientation along the guide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In the following, the present disclosure is explained in more detail with reference to the accompanying figures using examples of embodiments. The formulation figure is abbreviated in the drawings as Fig.

[0037] FIG. 1 schematically depicts a view of a stairlift according to an aspect of the present disclosure;

[0038] FIG. 2 schematically depicts a top plan view of a stairwell according to one or more embodiments shown and described herein;

[0039] FIG. 3 schematically depicts an illustrative flowchart for a method according to an aspect of the present disclosure; and

[0040] FIG. 4 schematically depicts an illustrative diagram of an exemplary speed profile according to one or more embodiments shown and described herein.

DETAILED DESCRIPTION

[0041] The described embodiments are merely examples that can be modified and/or supplemented in a variety of ways within the scope of the claims. Any feature described for a particular embodiment example may be used independently or in combination with other features in any other embodiment example. Any feature described for an embodiment example of a particular claim category may also be used in a corresponding manner in an embodiment example of another claim category.

[0042] FIG. 1 shows a stairlift 1, to which the embodiments described herein can be applied. The stairlift 1 includes a guide 2 formed as a rail and running parallel to the slope of a staircase 3 in a direction D, wherein the staircase 3 has a number of steps 3.1. The stairlift 1 further includes a carriage 6, which can move along the guide 2 in or against the direction D, and which includes a drive unit 7 and a chair 8, wherein the chair 8 is connected to the drive unit 7 in a pivotable manner by a leveling mechanism 9. For driving the carriage 6, positive engagements devices 2.1 are provided on the guide 2, which cooperate with a second drive (not shown) for driving the carriage 6 along the guide 2 in a translational movement, such as a driven pinion, of the drive unit 7.

[0043] The chair 8 includes arm rests 8.1 and a footrest 8.2 and user interaction device 11 in the form of a joystick. By pushing/pulling the user interaction device 11 to a corresponding side, the carriage 6 may be driven to the according side in the direction D. The user interaction device 11 are pictured in an upright position which is associated to an active state, while they might be folded, e.g. into a recess at the arm rest 8.1, to get deactivated and avoid unintended actuation.

[0044] The carriage 6 further includes a first drive 12 which is shown schematically and with which the carriage 6, in particular the chair 8 is rotatable around a vertical axle A. The first drive 12 may be a brushed or brushless DC motor, a servo motor or a stepper motor. With a rotational angle phi set by the first drive 12, the carriage 6 can be positioned to avoid collision with steps 3.1, or walls, to (pre)position for translational movement of the carriage 6 through a turn of the guide 2 at highest possible translational speed or to provide a comfortable and safe boarding position in a landing position of the carriage 6. Accordingly, the guide 2 can have a curved shape, which deviates from a straight line. The direction of travel D and/or the inclination of the guide 2 may change at least once during the course of the guide 2 and the guide 2 may run out horizontally at a landing position, wherein the chair 8 is hold in an upright position due to the leveling mechanism 9. Thus, the guide 2, or components thereof, follow a certain trajectory having turns around horizontal and/or vertical axles or both axles at the same time.

[0045] The carriage 6, the drive unit 7 thereof, may include a control unit 13, which is connected to the first drive 12 and with which a torque applied by the first drive 12 to the carriage 6 can be determined. Further, the carriage 6, via the control unit 13, may include or be communicatively coupled to sensors or other devices to measure the angle of rotation phi of the first drive 12, the torque applied by the first drive 12 and/or the rotational speed of the first drive 12. The carriage 6 may further include a weight sensor 10 to measure the mass of the chair 8 and/or a person carried on the chair 8.

[0046] As discussed above, the control unit 13 may be an electronic control unit, a central processing unit (CPU), and the like, for performing the functions as described herein. As such, the control unit 13 may be configured to receive, analyze and process sensor data, perform calculations and mathematical functions, convert data, generate data, control system components (e.g., the first drive, the second drive, the third drive, the carriage, and the like), and the like. The control unit 13 may include one or more processors, and other components, for example one or more memory modules that stores logic that is executable by the one or more processors and a database based on, for example, user inputs provided via the user interaction device. Each of the one or more processors may be a controller, an integrated circuit, a microchip, central processing unit or any other computing device.

[0047] FIG. 2 shows a top plan view of a stairwell 14, with a stairlift 1 therein. The stairwell 14 has walls 15.1, 15.2, 15.3, 15.4, and steps 3.1. Carriage 6 is drawn at two positions along guide 2, where it makes an angle phi relative to guide 2. The staircase 3 makes a turn of 90 degrees. In the turn, steps 3.1 narrow in the direction of the center of the turn. When carriage 6 is moved along the guide 2, the carriage 6 needs to be prevented from hitting the walls 15.1, 15.2, 15.3, 15.4 of the stairwell 14 or the steps 3.1. Whether there is a risk of this happening depends on inter alia the width of the stairwell 14 and the height of guide 2 above the steps 3.1. Even when guide 2 are mounted so high above the steps 3.1 that there is no risk of collision with steps 3.1 on the straight parts of the staircase 3, there may, for instance, be a local risk of collision in the turn due to the narrowing of steps 3.1. The risk of collisions with steps 3.1 in the turn is avoided by rotating the carriage 6 locally in the turn relative to the guide 2 around the vertical axle A in order to avoid collision with steps 3.1. The speed values and angle values describing the movement of the carriage 6 are defined in a speed profile, which defines at least the translational speed/acceleration of the carriage 6 along the guide 2 and the rotational speed/acceleration of the carriage 6 around the vertical axle A.

[0048] Now referring to FIG. 3, a method 20 to determine a speed profile for fast traveling along the guide 2 at high comfort and sufficient safety conditions includes in a first step 21 measuring a correlation between applied torque and resulting rotational acceleration for the first drive 12 with the specific person carried on the carriage 6. In an alternative second step 22 measuring the specific persons weight while the specific person is carried on the carriage 6 (e.g., via weight sensor 10). With the measured value, a specific mass moment of inertia is determined for the specific person in a third step 23. Either the specific mass moment of inertia is calculated from the value received from the first step 21 or the specific mass moment of inertia is estimated with the value received from the second step 22. In a fourth step 24, an optimal torque is set according to the specific mass moment of inertia received from the third step 23. This optimal torque may be set according to generally defined comfort conditions to avoid too fast or too slow rotation of the carriage 6, may be set to comfort conditions individually defined by the specific person and/or may be defined by regulations. Finally, in a fifth step 25, the speed profile is determined applying at the most the optimal torque with the first drive 12. Thus, the speed profile can be optimized for fast travelling with the optimal torque set.

[0049] FIG. 4 shows an speed profile 30 with the position of the carriage 6 along the guide 2 on the x-axis and the translational speed of the carriage 6 along the guide 2 and the rotational angle phi on the y-axis. A first graph 31 represents translational speed values of the carriage 6 along the guide 2 and a second graph 32 represents values of the rotational angle phi. At a position 33 of the guide 2, a specific angle phi has to be reached, e.g. for a turn of the guide 2 beginning at this position. Therefore the carriage 6 starts to rotate at position 34 at a certain torque of the first drive 12. The angle phi is then kept constant after the position 33, e.g. as long as the carriage 6 is in the turn. Afterwards, a counter wise rotation of the carriage 6 is conducted, e.g. to rotate the carriage 6 to an angle phi required at a landing position. The speed at the same time is kept at an optimal most of the time, while being reduced during the turn, e.g. to allow the angle phi at position 33 to be reached and/or to increase comfort in the turn.