EP3740413A1

EP3740413A1 - Transport device, particularly a baby carriage, comprising an electrical drive unit

Info

Publication number: EP3740413A1
Application number: EP18811162.9A
Authority: EP
Inventors: Joerg Baur; Norbert Martin; Jochen Pfister; Bertram SCHILLINGER; Stefan Groh
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-01-18
Filing date: 2018-11-15
Publication date: 2020-11-25
Also published as: CN111565994A; DE102018200771A1; WO2019141402A1; JP2021511251A

Abstract

The invention relates to a transport device (100) particularly a baby carriage, comprising a chassis (102) and a handle (110) for a user, where at least one drive wheel (132, 134) that can be driven by means of an electrical drive unit (140, 142) and is used to at least partially support a manual pushing or pulling operation of the transport device (100) by the user is arranged on the chassis (102), and the electrical drive unit (140, 142) can be controlled by means of a control device (200) associated with the transport device (100). According to the invention, the control device (200) is embodied so as to enable identification of the state of the ground (114) on which the transport device (100) is moved, by means of evaluation of sensor signals (152) detected by at least one acceleration sensor (150) associated with the transport device (100), in order to improve a corresponding electronic regulation of the electrical drive unit (140, 142) by means of the control device (200).

Description

description

title

Transport device, in particular stroller, with an electric drive unit

State of the art

The present invention relates to a transport device, in particular a stroller, with a chassis and with a handle for a user, wherein on the chassis at least one drivable by means of an electric drive unit driving wheel for at least partially support a manual sliding or pulling operation of the transport device is arranged by the user and the electric drive unit can be controlled by means of a control device associated with the transport device. Furthermore, the invention relates to a method for determining a respective condition of a substrate on which a transport device is moved.

Among other things, transport devices designed as prams are known from the prior art, which have electrical drives for the active sliding support of a user. In order to optimize a corresponding electronic control of the electric drive of such stroller, it is desirable to detect a condition of a surface on which the child car moves in each case as accurately as possible. Optical camera systems are often used for this purpose, the images of which are preferably evaluated in real time with the aid of image evaluation algorithms for detecting various substrates.

Disclosure of the invention

The present invention provides a transport device, in particular a stroller, with a chassis and with a handle for a user wherein at least one drive wheel drivable by means of an electric drive unit is arranged on the chassis for at least partially assisting a manual shift or pull operation of the transport device by the user and the electric drive unit can be actuated by means of a control device assigned to the transport device. By evaluating sensor signals which are detected by at least one acceleration sensor associated with the transport device, the control device is configured to detect a condition of a respective background on which the transport device is moved in order to improve one allow appropriate electronic control of the electric drive unit by means of the control device.

Due to the robust detection of the nature of the ground, the control of the electric drive unit can be improved or optimized, where out a high ease of use for the user results.

Preferably, the electric drive unit is integrated in the at least one drivable drive wheel. As a result, a particularly compact design of the drive unit is possible with a simultaneous reduction of the required mechanical components.

According to a preferred refinement, at least two drive wheels, each associated with a front axle and / or a rear axle of the chassis, can each be driven independently of one another by means of an associated electric drive unit. As a result, the electric drive acts symmetrically or on both sides on the transport device.

By means of a numerical evaluation of the sensor signals detected by the at least one acceleration sensor, at least substrates which are at least similar to the composition of asphalt, gravel, pavement, screed, green area, sand, ice and / or at least substrates can be distinguished from one another Snow is. As a result, the transport device can be used on practically all occurring substrates without loss of comfort. In a further embodiment, the sensor signals detected by the at least one acceleration sensor enable at least substantially a determination of acceleration values perpendicular to the ground over time (t). As a result, a sufficient reliability of the determination of the condition of the ground is possible.

In accordance with a further refinement, the at least one acceleration sensor is a 3D acceleration sensor for detecting acceleration values in three directions of the space. As a result, by means of the at least one acceleration sensor, in addition to the linear accelerations of the baby carriage along the x, y and z axes, the spin accelerations of the baby carriage about the x, y and z axes can also be determined.

In addition, the invention relates to a method for determining a respective condition of a substrate on which a transport device, in particular a stroller, in particular a transport device as described above, is moved. In the method according to the invention the following steps are provided:

a) detecting acceleration values, at least substantially perpendicular to the ground, by means of at least one acceleration sensor assigned to the transport device,

b) decomposing the acceleration values into discrete individual frequencies, c) calculating an amplitude sum from at least n individual frequencies, and

d) assigning the amplitude sum calculated in step c) to a preferably empirically ascertained reference amplitude sum of different frictional forces of different substrates for determining a background on which the child car is currently being moved.

As a result, a simple and rapid assignment of the arithmetically determined amplitude sums to the frictional forces of the transport device determined beforehand by practical test series on different substrates is known by means of a so-called look-up stored in the control device and known from information technology. Table possible. This table also contains a generally constant mass m of the transport device without one The object to be transported, for example, without a child, if appropriate as a function of an angle of inclination a of the ground in relation to the Wa-fair, according to the relationship F _g = F _N = m ^* g for a = 0 ° or F _N = m ^* g ^* cos ( a) for 0 ° <a <90 °.

According to a technically advantageous development, the decomposition of the acceleration values into discrete individual frequencies takes place by means of a Fourier transformation. As a result of this, a calculation model that is comparatively quickly numerically evaluable today is available.

In a further embodiment, the one amplitude sum of the acceleration values is calculated by summing n squares of n individual amplitudes of the individual frequencies and then dividing them by the number n. This results in a characteristic value of an amplitude sum for each background.

In accordance with a development of the method, at least the empirically determined reference sum amplitudes of different frictional forces of different backgrounds are stored in a look-up table. This makes it possible to record the nature of a substrate very quickly and precisely. The look-up table stored in the control device is preferably a value table that is well known from information technology.

In a further technically advantageous embodiment, at least acceleration values are recorded in three spatial directions. As a result, a virtually complete movement detection of the baby carriage over time is possible.

Brief description of the drawings

The invention is explained in more detail in the following description with reference to exemplary embodiments illustrated in the drawings. Show it:

1 shows a side view of a transport device designed as a stroller with a recognition of the nature of a substrate on which the transport device is moved, and 2 shows a greatly simplified block diagram of the sequence of the method according to the invention for determining the condition of a substrate on which a transport device is moved.

Description of the embodiments

1 shows a transport device 100, which is illustratively and by way of example designed as a child car 100 and is referred to below as "stroller 100". The stroller 100 preferably comprises e.g. scissor-type collapsible chassis 102, on which illustratively a recliner or seat pan 104 is arranged. On the chassis 102, a handle 110 is generally arranged, preferably as a height-adjustable, U-shaped bracket or as a handle bar for a push or pull operation of the stroller 100 in the direction of a double arrow 112 on a substrate 1 14 by a in the Drawings not shown user is formed. A pulling operation of the pushchair 100 is exemplified by a dashed section of the double arrow 112, while a corresponding pushing operation of the pushchair 100 is indicated by a portion of the double arrow 1 12 shown by a solid line.

The stroller 100 preferably has at least three wheels 120, 122, 124, 126. Preferably, two wheels on a rear axle 130 and a wheel on a front axle 128 are arranged, however, two wheels on the front axle 128 and a wheel on the rear axle 130 may be arranged. Four wheels 120, 122, 124, 126 are provided here on the chassis 102 by way of example only, with the wheels 120, 124, which are only visible here and located further forward relative to the plane of the drawing, each having the two wheels 122, 126 lying further behind in relation to the plane of the drawing cover. The wheels 120, 122 are preferably on both sides of the front axle 128 and the wheels 124, 126 are fastened to the rear axle 130 of the chassis 102 of the baby carriage 100. Of the at least three wheels 120, 122, 124, 126, at least one wheel is preferably designed as a drive wheel 132, 134. The at least one drive wheel 132, 134 may be driven by an electric motor by means of at least one electric drive unit 140, 142. In this case, the at least one drive wheel 132, 134 may be attached to the front axle 128 and / or the rear axle 130. orders be. At least two wheels are preferably designed as drive wheels 132, 134. The two wheels 124, 126 assigned to the rear axle 130 are preferably designed in each case as drive wheels 132, 134, which preferably serve to at least partially support the manual pushing or pulling operation of the pushchair 100 by the user. The drive wheels 132, 134 are each preferably driven independently of one another directly or indirectly via an unillustrated transmission by means of an electric drive unit 140, 142 and can be precisely controlled by means of a control device 200 or control device arranged by way of example in the region of the rear axle 130.

Deviating from the embodiment of a classic pushchair 100 shown here by way of example only, it can also be designed as a sports cart or buggy or as a twin or tandem pushchair or as a two-seat buggy. A rectangular coordinate system 199 with an x-axis, y-axis and a z-axis, each with an associated acceleration a _x , a _y , a _z, illustrates the position of all components in the space. The empty, unoccupied child carriage has a constant mass m, from which, in the case of the horizontal subsoil 114, where an inclination angle a of the subsoil 1 14 is essentially 0 °, a maximum effective weight force of F _g = m ^* g results.

The frictional force FR counteracting the direction of movement of the baby carriage 100 when a user force Fu is applied to the bracket 10 is, as indicated by the solid double arrow 1 12, equal to the product from the Ge in the case of the horizontally extending base 1 14 - weight force F _g or in this constellation equal normal force F _N and the friction coefficient m of the substrate 114. As a result, the tire is bung force to a considerable extent by the means of the control device 200 and the at least one acceleration sensor 150 to be determined loading Creativity of Underground 1 14.

An angle of inclination α of a slightly inclined background 114, indicated here only by dots, here amounts to approximately 7 °. The effective friction force FR, reduced in this constellation, is in turn equal to the product of the friction coefficient m of the ground 114 and the normal force FN, which follows from the equation FN = m ^* g ^* cos (a). To determine the inclination angle a, for example, an unillustrated electronic tilt sensor for Use come, the measuring signals also to the control device 200 ggfls. for further evaluation and for consideration in the detection of the condition of the substrate 1 14 can be transmitted.

For the detection of the condition of the substrate 1 14, the stroller 100 preferably has at least one acceleration sensor 150, which is formed at least for detecting acceleration values a _z along the z-axis of the coordinate system 199. In addition, the acceleration sensor 150 can be realized with a 3D acceleration sensor which records a detection of acceleration values a _x , a _y , a _z along the x-axis, the y-axis and the z-axis of the coordinate system 199, respectively and, if appropriate, additionally the measurement of rotational accelerations about the x-axis, y-axis, z-axis of the coordinate system 199 so that a complete detection of the movement of the baby carriage 100 in space during the electromagnetically assisted sliding movement. and drawing operation becomes possible.

Electrical measurement signals 152 of the at least one acceleration sensor 150 are fed to the control device 200 for further evaluation within the framework of the determination of the condition of the substrate 11. Notwithstanding the positioning of the acceleration sensor 150 in the region of the one drive wheel 132 of the rear axle 130, which is only shown here by way of example, it can also be arranged on the chassis 102, the lying or sitting trough 104 or at any other location on the baby carriage 100.

In the substrate 1 14 on which the stroller 100 moves, it may be, for example, asphalt, gravel, pavement of any design, screed, a green area, arable land, sand, watts, ice and / or snow.

The substrate 114 may also have any desired surface topography, that is, e.g. plan, wavy, partially inclined, bumpy or rippled.

All of these different properties of the substrate 114 can be reliably and independently of external influences, such as the weather and the user, solely by the evaluation of the process supplied by the at least one acceleration sensor 150 measurement signals in the form of at least determined acceleration values az along the z-axis of the coordinate system 199 by the control device 200. In this way, the electric drive units 140, 142 in the electrically assisted pushing and pulling operation of the baby carriage 100 can be controlled or regulated in dependence on the respective current condition of the substrate 114 in such a way that the best possible driving experience or a maximum possible driving experience is achieved Ease of use for a child accommodated in the stroller 100 and the user adjusts.

It should be noted that the design of the transport device 100 as a stroller, merely exemplary in nature and is not to be understood as a limitation of the invention. Thus, the transport device 100 may also be designed in the manner of any other transport device having a background determination according to the invention, e.g. like a wheelbarrow, a sack truck, a garbage bin.

2 shows a simplified block diagram of the sequence of the method according to the invention for determining the condition of a substrate on which a transport device, in particular a stroller, is moved. A measuring curve 170 shows the course of the vertical acceleration a _{z of} the baby carriage along the z-axis of the coordinate system determined according to a first method step a), preferably by means of the acceleration sensor (cf., Fig. 1, reference numeral 150) (cf. 1, reference numerals 100, 199) over time t. In a second method step b), the time profile of the acceleration value a _z in the form of the measurement curve 170 is preferably converted into a number of n discrete harmonic individual frequencies by means of a fast Fourier transformation 172 ("Fast Fourier Transformation" = "FFT"). .., _n decomposed over the time t, wherein here, by way of example only, n = 5 is selected. The additive superimposition of the individual frequencies AKI,..., 5 in turn yields the measurement curve A _z .

Preferably, n> 2 and a maximum value of n is limited only by the computing power available within the control device of the baby carriage. In general, for values of n between 5 and 100, sufficiently precise results are obtained with regard to the nature of the substrate on which the stroller is moved. In a third method step c), the calculation of an amplitude sum As from the exemplary embodiment of five individual frequencies aki,..., 5 determined by means of the fast Fourier transformation 172 from the acceleration values a _{z of} the measurement curve 170 takes place according to the empirical formula Ä _S ^ = ßj; with the

Reference numeral 174. In a last method step d), the numerically calculated amplitude sum As is assigned a nearest reference amplitude ARI _{,..., 4} . The reference amplitudes ARI _{,..., 4 of} the substrates are determined empirically in a suitable manner by extensive experiments and are preferably in a value table 180 or a "look-up table" within the control device 200 together with likewise determined metrologically and the reference amplitudes ARI _{,..., 4} line-by-line associated frictional forces

FRI _{, ..., 4} deposited. Further, the look-up table 180 includes the mass mw of the baby carriage, which is generally constant and relates to the empty stroller.

The exemplary only four AR with respective assigned friction forces FRI _{,..., 4} can be empirically determined, for example, by extensive driving tests with the child car on surfaces with different properties. The value FRI stands, for example, for gravel, while FR ₂ stands for asphalt or tar, for example, the value F _R3 applies to a paved subsoil, while the value FR _{4 stands} for a substantially smooth, in particular screed-like subsoil , Accordingly, all other textures occurring in practice are handled by a wide variety of substrates.

In the exemplary embodiment shown here, by way of example only, a clear maximum correspondence between the amplitude sum As calculated numerically by the mathematical relationship 174 and the empirically determined reference amplitude AR ₂ results from the table 180, from which by means of a suitable program algorithm within the control device can be derived that the stroller is moved in this case on a substrate with the nature of asphalt or tar. If the condition of the substrate on which the stroller is moved in the most electrically assisted sliding or pulling operation is uniquely determined, an improved and preferably optimal control or regulation of the electric drive units of the drive wheels of the stroller can be adapted to these circumstances by means of the control device (see Fig. 1, reference numerals 100, 132, 134, 140, 142, 200), resulting in an optimal ease of use for a child located in the stroller and the user results. The calculation of the amplitude sum As and the determination of the respective current base on which the stroller is moved is preferably carried out in real time, so that the control of the electric drive units 140, 142 by means of the control device 200 also has temporally fast changing properties of surfaces adequate adaptation of the behavior of the baby carriage conveyed by the electric drive units 140, 142 may react.

Claims

claims

1. Transport device (100), in particular stroller, with a Fahrge- (102) and with a handle (1 10) for a user, wherein on the chassis (102) at least one by means of an electric drive unit (140,142) driven drive wheel (132,134 ) is arranged for the at least partial support of a manual pushing or pulling operation of the transport device (100) by the user and the electric drive unit (140, 142) can be actuated by means of a control device (200) associated with the transport device (100) , characterized in that the control device (200) is designed to detect a condition of a respective background (16) by evaluating sensor signals (152) detected by at least one acceleration sensor (150) associated with the transport device (100). 1 14) on which the transport device (100) is moved, to improve a corresponding electronic control the electric drive unit (140,142) by means of the control device (200) to allow.

2. Transport device according to claim 1, characterized in that the electric drive unit (140, 142) is integrated into the at least one drivable drive wheel (132, 134).

3. Transport device according to claim 1 or 2, characterized in that at least two each of a front axle (128) and / or a rear axle (130) of the chassis (102) associated drive wheels (132,134) each by means of an associated electric drive unit (140,142) are independently drivable.

4. Transport device according to one of the preceding claims, characterized in that by means of a numerical evaluation of the at least one acceleration sensor (150) detected sensor signals (a _z ) with the aid of the control device (200) at least substrates (1 14) vonei- whose nature is at least similar to that of asphalt, gravel, pavement, screed, green area, sand, ice and / or snow.

5. Transport device according to one of the preceding claims, characterized in that the at least one acceleration sensor (150) detected sensor signals (a _z ) at least substantially a determination of acceleration values (a _z ) perpendicular to the ground (1 14) via allow the time (t).

6. Transport device according to one of the preceding claims, characterized in that the at least one acceleration sensor (150) is a 3D acceleration sensor for detecting acceleration values (a _x , a _y , a _z ) in three directions of the space.

7. A method for determining a respective condition of a substrate (114) on which a transport device (100), in particular a baby carriage, in particular according to one of claims 1 to 6, is moved, characterized by:

a) detecting acceleration values (a _z ), at least substantially perpendicular to the ground (1 14), by means of at least one acceleration sensor (150) associated with the transport device (100),

b) decomposing the acceleration values (a _z ) into discrete individual frequencies

(3k1, ... n),

c) calculating an amplitude sum (As) from at least n single frequencies (aki, ..., _n ), and

d) assigning the amplitude sum (A s) calculated in step c) to a reference empirical sum (AR) of different friction forces (FR) of different substrates (1 14) for determining a background (1 14) as close as possible to the empirically determined value on which the transport device (100) is currently being moved.

8. The method according to claim 7, characterized in that the decomposition of the acceleration values (a _z ) into discrete individual frequencies (aki, ... n) by a Fourier transformation (172) takes place.

9. The method according to claim 8, characterized in that the one

Amplitude sum (As) of the acceleration values (a _z ) by summing n squares of n individual amplitudes (a _k ) of the individual frequencies

(a _{ki, ... n} ) and then dividing by the number n is calculated.

10. The method according to claim 9, characterized in that at least the empirically determined reference sum amplitudes (AR) of different friction forces (FR) of different substrates (1 16) in a look

Up table (180) are deposited.

1 1. A method according to any one of claims 7 to 10, characterized in that at least acceleration values (ax, ay, az) are detected and evaluated in three spatial directions.