WO2018215163A1

WO2018215163A1 - Wheelchair with at least one electric auxiliary drive

Info

Publication number: WO2018215163A1
Application number: PCT/EP2018/060787
Authority: WO
Inventors: Andreas BIEDERSTÄDT; Renato HOHMANN; Thomas Brendel; Heinrich Perk
Original assignee: Otto Bock Mobility Solutions Gmbh
Priority date: 2017-05-22
Filing date: 2018-04-26
Publication date: 2018-11-29
Also published as: DE102017111129A1; DE102017111129B4

Abstract

The invention relates to a wheelchair comprising a frame and two drive wheels, which can be driven both manually by means of forces introduced into the wheels in successive push-start phases as well as by means of at least one electric auxiliary drive. According to the invention, the auxiliary drive takes over the function of a holding brake on inclined terrain paths or downhill paths in that the speed curve of each of the drive wheels is detected and then, if both drive wheels falls below a specified speed to a standstill, the auxiliary drive is activated such that the wheelchair remains at a standstill for an interval of time.

Description

Wheelchair with at least one electric auxiliary drive

The invention relates to a wheelchair with a frame and at least two drive wheels which can be driven both manually by forces applied to them in successive successive startup phases and by means of an electrical auxiliary drive.

Such a wheelchair is known for example from DE 10 2012 103 136 B4. In this wheelchair, the torque applied by the drive means is selected not only as a function of the muscle force of the user introduced into the gripping rings of the drive wheels, but also by the detected inclination of the wheelchair in the direction of travel and thus of the slope of the terrain. Through this configuration, mountain rides can be handled by the wheelchair mobile without increased muscle use. The support provided by the drive means causes the wheelchair to travel a sufficient distance to allow the wheelchair user to grasp the gripping rings before the wheelchair comes to a standstill or even rolls back. Even when driving downhill, the muscular strength of the wheelchair user can be adequately supported so as not to allow the wheelchair to become too fast. About the control device, the drive device can be braked to reach a maximum speed of the wheelchair, the maximum speed can be adjusted.

From DE 10 2014 103 907 A1 a wheelchair with auxiliary drive is known, in which sensors are integrated in the seat, are detected by the movements of the person driving the wheelchair. In addition to the driver's position and orientation data, the position and orientation data of the wheelchair are also recorded. The setpoint torque of the drive wheel is detected by the impressed forces on the grip ring. Based on the sensor information on the torque sensors between the gripping ring and the wheel or the human-machine interface and the simultaneously detected movement of the arms and / or the upper body, the sensors recognize the driver's intention to act and the muscle impedance is estimated. By appropriate control of the auxiliary drive of the Supports drivers in the performance of his action, but without replacing or overriding his action.

DE 10 2005 048 374 A1 discloses a wheelchair with an auxiliary drive, which is provided for keeping the driving speed constant. For this purpose, a switch-on device for the auxiliary drive is provided.

EP 2 740 455 B1 describes a wheelchair with a sensor device for detecting the driving force manually introduced by the user. Depending on the driving force, the drive behavior of the drive motor is maintained after reaching a limit speed which corresponds to a predetermined limit speed of the wheelchair.

In WO 2013/006818 a wheelchair is described with an auxiliary drive, in which the auxiliary drive is switched on when the user drives the drive wheels manually. For this purpose, the linear acceleration of the wheelchair or the angular acceleration of the drive wheels is determined. If a defined threshold for acceleration is exceeded, the system detects that a drive movement is taking place. If this threshold is undershot, the system recognizes that the user wishes to decelerate the wheelchair. Accordingly, the auxiliary drive is switched on or switched off. The auxiliary drive consists of a drive wheel, which is arranged centrally under the seat of the wheelchair, so that a drive in straight drive and a rotational movement is excluded, which would have to compensate for the user. The auxiliary drive can also be switched on deliberately by pressing a switch.

The invention is therefore based on the object to improve the control of the auxiliary drive so that the auxiliary drive can be used to act as a holding brake when the wheelchair is stopped on slope or terrain and should remain in the holding position.

To solve the problem, the generic wheelchair is characterized in that on terrain gradient or downhill sections of the auxiliary drive the function of Holding brake is adopted by the speed profile of each of the drive wheels is detected and then when both drive wheels below a predetermined speed to a stop, the auxiliary drive is switched so that the wheelchair remains stationary for a time interval.

This time interval can be a few seconds or even take so long until this braking function is switched off or the wheelchair user again initiates driving forces in the gripping rings of the drive wheels. The speed can be, for example, v _m in = 1 km / h. Standstill of the wheelchair can already be detected if the speed (still) is not exactly 0 km / h, but deviates in the range of measurement inaccuracies and / or tolerances thereof.

In order to detect inclines or inclines, an inclination sensor is preferably provided.

The auxiliary drive preferably consists of two each having an output shaft having, combined into one unit electric motors and each output shaft is connected at its free end to a drive axle or a wheel hub of each drive wheel.

The speed profile of the drive wheels 1, 2 is preferably measured by measuring the rotational speed of the electric motors permanently connected to the drive axles or the wheel hubs.

If the auxiliary drive to assist the wheelchair user to drive the wheelchair is to be used to control the auxiliary drive a plurality of successive intervals between two startup phases and the speed of the wheelchair as a function of time evaluated and it is determined during the startup phases, the acceleration of the wheelchair and the Auxiliary drive switched on when the time intervals fall below a predetermined value and at the same time the acceleration falls below a predetermined value. For example, the limit of the time intervals may be 1.5 s and the limit value of the acceleration may be 2.5 ms ^-2 . The Ben are essentially arbitrary and depend primarily on the driver's constitution or desire for propulsion support.

Preferably, at least two time intervals are evaluated in an evaluation interval. In particular, preferably three, wherein the speed at which the auxiliary drive is switched on, is freely configurable and in particular the last measured speed is to be used. Due to the sharp increase in the ratio of speed change to time interval, the last measured speed can not be reached immediately. However, the force to be applied manually by the user is significantly lower, resulting in weak fluctuations in longer roll phases.

Preferably, the speed, which was measured (reached) during a maximum of a thrust phase in the evaluation interval, is not exceeded when the auxiliary drive is connected.

Preferably, the speed of the wheelchair is kept constant by means of the control of the speed of the auxiliary drive.

Preferably, the acceleration of the wheelchair is determined by measuring the speed of at least one of the permanently connected to the drive axles or the wheel hubs electric motors.

With the help of a drawing, an embodiment of the invention will be described in more detail below:

Show it

Figure 1 - the perspective view of a wheelchair; the arrangement of a first auxiliary drive between the drive wheels in a perspective exploded view;

Figure 3 - an exploded perspective view of the auxiliary drive; a perspective view of an inserted into the wheelchair frame auxiliary drive;

FIG. 5 shows a first speed-time diagram; Figure 6 - a second speed-time diagram.

The wheelchair consists essentially of the frame 3, on which the seat 5, the footrest 6 and the drive wheels 1, 2 and the steering wheels 7, 8 are mounted. Between the drive wheels 1, 2 of the auxiliary drive 4 is arranged, which consists of at least one electric motor 10, 20. The accumulators for supplying energy to the electric motor or motors 10, 20 are provided at a suitable location in the frame 3. Outside, each of the drive wheels 1, 2 is provided with a gripping ring 1 .1 or 2.1, via which the wheelchair user introduces the driving forces to the drive wheels 1, 2. For each drive wheel 1, 2, a separate electric motor 10, 20 is provided. The control for the motors 10, 20 and the sensors required for this purpose can be integrated in the motor housing.

In the drive unit shown in Figures 1 and 2, the electric motors 10, 20 are integrated into the axle tube 4.1 and not visible from the outside. This has the advantage that the auxiliary drive 4 for third parties is not immediately visible and thus is not readily apparent that the auxiliary drive 4 is connected to the support. In addition, this embodiment also has the advantage that particularly small electric motors are used, resulting in weight reduction. The output shafts 10.1, 20.1 are provided with an outer toothing 10.2, 20.2, which engages in an internal toothing 9.1 of the wheel hub 9. As a result, the drive motors 10, 20 are permanently connected to the drive wheels 1, 2 and also run with when the auxiliary drive 4 is not switched on. Not shown sensors, a controller, also not shown, the speed of the electric motors 10, 20 at any time determine what is necessary to switch on the auxiliary request 4 at the appropriate time, which is still to be explained.

The auxiliary drive 4 shown in Figure 4 with the two electric motors 10, 20 has a handle 30 and can be used if necessary in the wheelchair frame 3. The control of the motors 10, 20 may be integrated in the housing. To facilitate the onset of the auxiliary drive 4 are provided on the frame 3 upwardly open forks 3.1. The provided on the axle tubes 4.1 coupling means 4.2 for connection to the frame 3 is formed as a partial circumferential projection having two lateral contact surfaces, which interact with contact surfaces 3.2 of the forks 3.1. About the output shafts 10.1, 20.1 of the auxiliary drive 4 with the drive axle 1 a and the hub 9 of each drive wheel 1 .2 is connected. This auxiliary drive 4 is described in detail in German Patent Application 10 2016 1 18 032.

Reference to the figures 5 and 6 will be explained below, as the connection of the auxiliary drive 4 takes place. Figures 5, 6 show a speed-time diagram in which the speed v of the wheelchair in km / h over the time (t) in seconds is plotted. The wave-shaped curve results from the successive startup phases Si, Si + i, ... in which the wheelchair user manually acts on the handrims 1 .1, 2.1 and drives the wheelchair in batches. In order to determine the speed v of the wheelchair, the speed of the electric motors 10, 20 permanently connected to the drive wheels 1, 2 or their output shafts 10.1, 20.1 is determined. The acceleration of the wheelchair (-) is determined in several start-up phases S. At the same time, the time intervals Ti between two startup phases Si, S are determined. It can be seen in FIGS. 5 and 6 that the first time interval Ti between the first startup phase Si and the second startup phase S2 is greater than the time interval T2 between the second startup phase S2 and the third startup phase S3. Ti is about 1, 35 s and T2 about 1, 0 s. If the time intervals T, a predetermined value x below, for example, less than 1 s and the acceleration of the

Wheelchair falls below a predetermined value γ, for example 2.5 ms ^-2 ,

the auxiliary drive 4 is switched on. This can be seen in the diagrams because the curve flattens. Characterized that the acceleration of the wheelchair e ^rm ^'tte' ^t ^'st>' ^st the switching on of the auxiliary drive 4 regardless of the Ge ^¬

speed of the wheelchair. The maximum speed v _ma x, with which the auxiliary drive 4 is switched on, corresponds to the maximum speed v, which was determined during a start-up phase S. The evaluation intervals amount to at least two startup phases Si, S ₁ +1. It is also possible to evaluate three or more startup phases. From the curve in the diagram of Figure 5 it can be seen that the auxiliary drive 4 engages only supportive, so the wheelchair user continues to apply on the gripping rings 1 .1, 2.1 driving force. The flat curve in the diagram of Figure 6 after the time t = 5 s can be seen that no more manual drive forces are introduced, but the auxiliary drive 4 alone drives the wheelchair, the speed v _ma x of about 5 km / h of speed V3 corresponds to that the wheelchair has reached at the end of the third start phase S3. It is also possible that the wheelchair user activates the auxiliary drive 4 manually. In this case, the speed V2 of the auxiliary drive 4 then corresponds to the last measured speed v of the wheelchair (the drive wheels 1, 2).

The auxiliary drive 4 can also take over the function of a holding brake. For this purpose, a tilt sensor 15 is arranged on the wheelchair, which is connected to the control of the auxiliary drive 4 and is detected by the, whether the wheelchair copes with a slope or a gradient or is on a level track. Also, the tilt sensor 15 could be integrated into the housing of the motors 10, 20. The speed profile of each of the drive wheels 1, 2 is about the speed the motors 10, 20 determined. In FIGS. 5, 6 it can be seen that two curves are superimposed. Since the wheelchair is driving straight ahead, these curves are very close to each other. The speed of the drive motors 10, 20 corresponds to the speed of the two drive wheels 1, 2. If both drive wheels 1, 2 a predetermined speed (for example, v _m in = 1 km / h or v _m in = 0.75 km / h) until the Understood class, the auxiliary drive 4 is switched so that the wheelchair for a predetermined time interval Z remains at a standstill or until the auxiliary drive 4 is turned off manually. The time interval Z can continue until the wheelchair user again introduces driving forces into the gripper rings 1 .1, 2.1. About the tilt sensor 15, the controller detects whether the wheelchair is going uphill or downhill and thus the direction of rotation of the drive motors 10, 20 is controlled accordingly. When driving uphill and standstill of the wheelchair, the drive motors 10, 20 are driven in the direction of travel, when driving downhill against the direction of travel.

LIST OF REFERENCE NUMBERS

1 drive wheel 1 .1 gripping ring

1 a drive axle

2 drive wheel 2.1 gripping ring

3 frames

3.1 fork

3.2 contact surface

4 auxiliary drive 4.1 axle tube

5 seat

6 footrest

7 steering wheel

8 steering wheel

9 wheel hub

9.1 Internal toothing

10 drive motor

10.1 output shaft

10.2 External teeth 15 Inclination sensor 20 Drive motor

20.1 output shaft

20.2 External teeth 30 Handle t time

Ti time interval

51 startup phase

52 Start-up phase Si Start-up phase

Si + i start-up phase v speed

V2 speed

Vmax speed

Vmin speed

Z time interval -) acceleration

Claims

claims

1 . Wheelchair with a frame (3) and two drive wheels (1, 2) which can be driven both manually by forces applied to them in successive starting phases (S) and by means of at least one electric auxiliary drive (4), characterized in that on terrain -Steigungsoder fall stretch of the auxiliary drive, the function of a holding brake is assumed by the speed profile of each of the drive wheels (1, 2) is detected and then, when both drive wheels (1, 2) falls below a predetermined speed to a stop, the auxiliary drive is so switched in that the wheelchair remains stationary for a time interval (Z).

2. Wheelchair according to claim 1, characterized in that for detecting pitch distances, a tilt sensor (15) is provided.

3. Wheelchair according to claim 1 or 2, characterized in that the auxiliary drive (4) consists of two each having an output shaft (10.1, 20.1) comprising, combined into one unit electric motors (10, 20) and each output shaft (10.1, 20.1) to its free end with a drive axle (1 a) and a wheel hub (9) each have a drive wheel (1, 2) is connected.

4. Wheelchair according to one of the preceding claims, characterized in that for detecting the speed profile of the drive wheels, the rotational speed of the permanently with drive axles (1 a) or wheel hubs (9) of the drive wheels (1, 2) connected electric motors (10, 20) measured becomes.

5. Wheelchair according to one of the preceding claims, characterized in that the auxiliary drive (4) is used to drive support and for controlling the auxiliary drive (4) a plurality of successive intervals (Ti) between two startup phases (Si, SH) and the speed profile of the wheelchair be evaluated as a function of time and during the startup phases (Si, Si + i) the acceleration of the roll

chair is determined and the auxiliary drive (4) is switched on when the time intervals (Ti) below a predetermined value x while the

Acceleration falls below an intended value (y).

6. Wheelchair according to claim 5, characterized in that at least two, preferably three successive intervals (Ti) are evaluated between two startup phases in a Auswerteintervall.

7. Wheelchair according to claim 5 or 6, characterized in that a speed (V2) with which the auxiliary drive (4) is switched on, is freely configurable.

8. Wheelchair according to one of claims 5 to 7, characterized in that the speed (V2) with which the auxiliary drive (4) is switched on, the maximum speed reached in the evaluation interval (v _ma x) does not exceed.

9. Wheelchair according to one of claims 5 to 8, characterized in that the speed (v _CO nst) of the wheelchair by means of the control of the speed (V2) of the auxiliary drive (4) is kept constant.

10. Wheelchair according to one of claims 4 to 9, characterized in that for determining the acceleration (-) of the wheelchair, the speed of at least one of the permanently with the drive axles (1 a) and wheel hubs (9) connected to the electric motor (10, 20) is measured.