MUSCLE-POWERED WHEELCHAIR AND METHOD FOR CONTROLLING AN AUXILIARY DRIVE FOR SAME

Abstract

It is already known in the prior art to provide muscle-powered wheelchairs with an auxiliary drive, which in the event of a force stress is switched on as needed, and the coupled-in muscular power is increased. Thus far, however, it has not been possible to control the application of the force, which in each case is coupled in intermittently, in such a way that it may be applied in different magnitudes. If a sensor system has sufficient sensitivity to fine movements, the detection for coarse movements is too imprecise, and for a more precise detection of coarse movements, fine movements become overly intensified.

The invention therefore provides that at least one force element that is elastically deformable is associated with the wheelchair. Since the deformation becomes more and more intense with increasing force, this results in natural damping of the coupled-in force, which may be detected by a sensor. As a result, a wheelchair according to the invention may be controlled in a targeted manner for fine movements as well as for faster, coarser movements.

Claims

1. A muscle-powered wheelchair with an auxiliary drive, comprising two drive wheels (4) with wheel rims (5) and electrical drive means (3), a push rim (8) being associated with each of the wheel rims (5) by means of at least two connecting elements (9) that are distributed over the circumference of the drive wheels (4), characterized in that the wheel rims (5) or the push rims (8) form an elastically deformable force element with which at least one signal generator (10) is associated, the signal generator detecting an elastic deformation of the force element in the radial direction and generating a travel signal corresponding to the degree of deformation of the force element, the at least one signal generator (10) on the input side being in signal connection with a control unit (15), which in turn on the output side is in signal connection with control inputs of the electrical drive means (3).

2. The wheelchair according to claim 1, characterized in that the connecting elements (9) are articulatedly connected to each of the wheel rims (5) by means of a first pivot bearing (11), and to the push rim (8) by means of a second pivot bearing (12).

3. The wheelchair according to claim 2, characterized in that the first pivot bearing (11) and/or the second pivot bearing (12) are/is designed as a roller bearing.

4. The wheelchair according to claim 1, characterized in that the connecting elements (9) are connected to the push rim (8) by means of a push rim bracket (7) that points radially inwardly or outwardly from the push rim (8), [or] are connected to the wheel rim (5) by means of a bearing point (6) that points radially outwardly or inwardly from the wheel rim (5).

5. The wheelchair according to claim 1, characterized in that the at least one signal generator (10) is a Hall probe (13) which is situated at the wheel rim (5) or at the push rim (8) and faces a connecting element (9), and which detects a movement of a magnet (14) situated at this connecting element (9).

6. The wheelchair according to claim 1, characterized in that the at least one signal generator (10) is a bending beam or a double bending beam, on the outer side of which a strain gauge is situated.

7. The wheelchair according to claim 1, characterized in that the at least one signal generator (10) is a magnetostrictive sensor, a magnetoresistive sensor, an inductive sensor, or an optical sensor.

8. The wheelchair according to claim 1, including multiple signal generators (10), preferably one signal generator (10) at each connecting element (9).

9. A muscle-powered wheelchair with an auxiliary drive, comprising two drive wheels (4) with wheel rims (5) and electrical drive means (3), a push rim (8) being associated with each of the wheel rims (5) by means of at least two connecting elements (9) that are distributed over the circumference of the drive wheels (4), characterized in that the connecting elements (9) form elastically deformable force elements with which at least one signal generator (10) is associated, the signal generator detecting an elastic deformation of the force element in its longitudinal direction and generating a travel signal corresponding to the degree of deformation of the force element, the at least one signal generator (10) on the input side being in signal connection with a control unit (15), which in turn on the output side is in signal connection with control inputs of the electrical drive means (3).

10. The wheelchair according to claim 9, characterized in that the connecting elements (9) are articulatedly connected to each of the wheel rims (5) by means of a first pivot bearing (11), and to the push rim (8) by means of a second pivot bearing (12).

11. The wheelchair according to claim 10, characterized in that the first pivot bearing (11) and/or the second pivot bearing (12) are/is designed as a roller bearing or slide bearing.

12. The wheelchair according to claim 1, characterized in that the push rim is omitted at one wheel rim (5), and the control is made possible only by means of the push rim (8) at the other wheel rim (5).

13. A method for controlling an auxiliary drive for a muscle-powered wheelchair (1) comprising two drive wheels (4) with wheel rims (5), and push rims (8) that are supported on the wheel rims by means of articulatedly fastened connecting elements (9) that are distributed over the circumference of the wheel rims (5), for generating a travel signal for electrical drive means (3) that are connected to the drive wheels (4), the wheel rims (5) or the push rims (8) as a force element being elastically deformed in the radial direction by application of force via muscular power, at least one signal generator (10) generating a travel signal corresponding to the elastic deformation of the force element and transmitting the travel signal to a control unit (15) for activating the electrical drive means (3), and the drive means (3) being activated by means of the control unit (15), due to the travel signal of the signal generator (10).

14. The method according to claim 13, characterized in that the at least one force element is the at least one push rim (8) or at least one of the wheel rims (5).

15. The method according to claim 14, characterized in that a deflection, in the same direction, of multiple connecting elements (9) distributed over the circumference of the wheel rims (5) is converted by the control unit (15) into a travel signal in the rotational direction of the deflection.

16. The method according to claim 15, characterized in that the travel signal is stronger, corresponding to faster travel, the greater the deflection of the particular connecting element (9).

17. The method according to claim 15, characterized in that a deflection, not in the same direction, of multiple connecting elements (9) distributed over the circumference of the wheel rims (5) is converted by the control unit (15) into some other type of control signal.

18. A method for controlling an auxiliary drive for a muscle-powered wheelchair (1) comprising two drive wheels (4) with wheel rims (5), and push rims (8) that are supported on the wheel rims by means of articulatedly fastened connecting elements (9) that are distributed over the circumference of the wheel rims (5), for generating a travel signal for electrical drive means (3) that are connected to the drive wheels (4), the connecting elements (9) as force elements being elastically deformed in their longitudinal direction by application of force via muscular power, at least one signal generator (10) generating a travel signal corresponding to the elastic deformation of the force elements and transmitting the travel signal to a control unit (15) for activating the electrical drive means (3), and the drive means (3) being activated by means of the control unit (15), due to the travel signal of the signal generator (10).

19. The method according to claim 13, characterized in that multiple travel signals and/or other types of control signals are combined into a signal sequence.

20. The method according to claim 13, characterized in that the control unit (15) is self-learning, and in particular recognizes and learns common signals and optionally signal sequences, and in the event of deviations, compensates for erroneous inputs and thereby adapts to the physical condition of a user.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the drawings:

[0028] FIG. 1 shows a muscle-powered wheelchair with push rims suspended on the wheel rims, in a perspective illustration,

[0029] FIG. 2a shows a detail of the suspension of a push rim at a wheel rim, together with a cross section of a connecting element in the neutral position, in a perspective partial cross-sectional illustration,

[0030] FIG. 2b shows the detail according to FIG. 2a in a deflection of the connecting element,

[0031] FIG. 3 shows a push rim suspended on a wheel rim, in a schematic top view,

[0032] FIG. 4 shows a push rim suspended on a wheel rim via compressible connecting elements, in a rest position,

[0033] FIG. 5 shows the push rim according to FIG. 4 in a deflected position, and

[0034] FIG. 6 shows a connection diagram with sensors, actuators, and a control unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] FIG. 1 shows a muscle-powered wheelchair 1 that is equipped with two drive wheels 4. These drive wheels 4 have push rims 8 that are suspended on wheel rims 5 of the drive wheels 4. By means of the push rims 8, a user of the wheelchair 1 may introduce muscular power into the drive wheels 4 in order to move the wheelchair 1 forward. The wheelchair 1 has an auxiliary drive which couples an additional force contribution to the coupled-in muscular power in order to assist the user with the drive of the wheelchair 1. For this purpose, the drive wheels 4 each have a hub motor, not shown here, as an electrical drive means 3 that is fed via an energy store 2. Provided as an energy store 2 are storage batteries which may be charged by recuperation during downhill travel or by an external charging voltage. The wiring of the drive means 3 and of the energy store 2 to further components is illustrated in greater detail in FIG. 6.

[0036] The suspension of the push rims 8 on the wheel rims 5 of the drive wheels 4 takes place at bearing points 6 of the wheel rims 5, which are uniformly distributed over the circumference thereof. Three bearing points 6 are preferably provided, since this allows a defined bearing of the push rim 8, but also permits sufficient freedom for a deformation of the push rim 8. This is necessary due to the fact that in the present example, the push rim 8 serves as a force element which is used as damping during the introduction of muscular power, but which allows a displacement of the push rim 8 relative to the wheel rim 5.

[0037] When the user pushes against the wheelchair 1 by introducing muscular power into a push rim 8, initially the push rim 8 moves forward in the direction of the introduced force. Due to the uniform bearing of the push rim 8 at push rim brackets 7 corresponding to the bearing points 6, the forward movement is converted into a rotational movement. However, this movement is hindered by connecting elements 9 that each connect a push rim bracket 7 to a bearing point 6. Although the connecting element 9 is connected to the bearing point 6 via a first pivot bearing 11, and to the push rim bracket 7 via a second pivot bearing 12, and the push rim 8 in this regard is suspended only via joints, a deflection of the connecting elements 9, as shown in FIG. 3, ensures an enlargement of the radius of a circle via the particular second pivot bearing 12. If only rigid elements were used in the system, this movement as a whole would be completely rigid, despite the joints. However, due to the push rim 8 being designed as an elastically deformable force element, for example by manufacturing the push rim 8 from spring steel, the push rim 8 is able to deform, thus allowing a deflection of the connecting elements 9, which may then be detected. The push rim 8 due to its deformation acts as damping, so that a slight deformation initially allows a comparatively strong deflection, while with increasing force, the deflection becomes ever more difficult to increase. Therefore, the user will not go into a hard stop, so that the operation of the wheelchair is very comfortable and very uniform.

[0038] As shown in FIG. 2a, a magnet 14 that is present in the measuring range of a Hall probe 13, opposite from the magnet 14, is situated at one end of the connecting element 9. FIG. 2a shows the neutral position of the push rim 8 without deflection relative to the wheel rim 5, so that the magnet 14 is situated centrally above the Hall probe 13. If the push rim 8 is now pushed to the right in the illustration, the connecting means 9 deflects, on the one hand by the push rim 8 compressing, and on the other hand by the connecting means 9 simultaneously rotating about the first pivot bearing 11 with respect to the wheel rim 5, and about the second pivot bearing 12 with respect to the push rim 8. As a result, the magnet 14 moves in the sensor range of the Hall probe 13, so that the magnetic field of the Hall probe changes, and an electrical output signal is generated that corresponds to the degree of elastic deformation of the push rim 8.

[0039] FIGS. 4 and 5 show one alternative in which the push rim 8 or the wheel rim 5 is not deformed or not solely deformed; rather, the deformation takes place primarily in the connecting elements 9. An example of compression of a compression spring 16 that is provided in the connecting elements 9 for this purpose is shown. The degree of compression of the compression spring may be determined via a path sensor, for example, when a deflection of the connecting elements 9 results from a movement of the push rim 8. In this regard, if the push rim 8 in FIG. 5 is deflected to the left relative to its position in FIG. 4, the connecting elements 9 rotate in their first pivot bearings 11 and second pivot bearings 12, whereby the pivot bearings 11 and 12 move away from one another. The compression spring 16 is compressed due to the fixed absolute length of the connecting means 9. However, this compression occurs elastically and thus reversibly, and also nonlinearly, so that the push rim 8 must be deflected against increasingly growing spring pressure, and resets after being released.

[0040] Firstly, two signal generators 10, namely, one for each drive wheel 4, are sufficient for the entire wheelchair 1. Multiple signal generators 10 for each drive wheel 4 are possible, and then allow pressure signals and knocking signals on the push rim 8 to be converted into control signals. For this purpose, the signal generators 10 together with a control unit 15 of the wheelchair 1 are in signal connection, and relay measured signals, for example in the form of electrical output signals of Hall probes 13 used, to the control unit 15. Provided on the output side of the control unit 15 are electrical drive means 3, for example in the form of hub motors, which are activated corresponding to the signals of the signal generators 10. The drive means 3 as well as the control unit 15, and via the control unit, the signal generators 10, are supplied with voltage from an energy store 2.

[0041] Thus, a muscle-powered wheelchair is described above which allows precise detection of the introduced muscular power, but which is still sufficiently robust to operate the wheelchair in everyday situations, and which has no hard stop despite a small actuating travel path. Also described is a method for operating such a wheelchair which achieves this object.

LIST OF REFERENCE NUMBERS

[0042] 1 wheelchair [0043] 2 energy store [0044] 3 drive means [0045] 4 drive wheel [0046] 5 wheel rim [0047] 6 bearing point [0048] 7 push rim bracket [0049] 8 push rim [0050] 9 connecting element [0051] 10 signal generator [0052] 11 first pivot bearing [0053] 12 second pivot bearing [0054] 13 Hall probe [0055] 14 magnet [0056] 15 control unit [0057] 16 compression spring