U.S. patent application number 10/496503 was filed with the patent office on 2005-04-28 for position adjustment of a vehicle car body.
Invention is credited to Streiter, Ralph.
Application Number | 20050087098 10/496503 |
Document ID | / |
Family ID | 7706628 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050087098 |
Kind Code |
A1 |
Streiter, Ralph |
April 28, 2005 |
Position adjustment of a vehicle car body
Abstract
The invention relates to the position adjustment of a car body
(1) of a track-guided vehicle, particularly of a rail vehicle, with
regard to at least one undercarriage (5) of the vehicle. To this
end, a transversal acceleration of the car body (1) transversal to
a car body longitudinal axis is determined and a transversal
position of the car body (1) with regard to the at least one
undercarriage (5) is adjusted according to the determined
transversal acceleration. A first transversal acceleration of the
car body (1) in a first transverse direction transversal to the car
body longitudinal axis and a second transversal acceleration of the
car body (1) in a second transverse direction transversal to the
car body longitudinal axis and transversal to the first transverse
direction are determined.
Inventors: |
Streiter, Ralph; (Stuttgart,
DE) |
Correspondence
Address: |
HOWREY SIMON ARNOLD & WHITE LLP
C/O IP DOCKETING DEPARTMENT
2941 FAIRVIEW PARK DR., SUITE 200
FALLS CHURCH
VA
22042
US
|
Family ID: |
7706628 |
Appl. No.: |
10/496503 |
Filed: |
November 2, 2004 |
PCT Filed: |
November 12, 2002 |
PCT NO: |
PCT/EP02/12635 |
Current U.S.
Class: |
105/453 |
Current CPC
Class: |
B60G 17/019 20130101;
B60G 2400/1042 20130101; B61F 5/22 20130101 |
Class at
Publication: |
105/453 |
International
Class: |
B61F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 23, 2001 |
DE |
101 57368.5 |
Claims
1. A device for the position adjustment of a car body (1) of a
track-guided vehicle, in particular a rail vehicle, with regard to
at least one undercarriage (5) of the vehicle, with at least one
actuator (7) for the adjustment of a transversal position of the
car body (1) relative to the undercarriage (5) transversal to a car
body longitudinal axis, a transversal acceleration measuring device
for determining the transversal acceleration of the car body (1)
and an adjustment device (20) for the adjustment of the relative
transversal position of the car body (1) as a function of the
measured transversal acceleration of the car body (I), whereby the
transversal acceleration measuring device is connected to the
adjustment device (20) and whereby the adjustment device (20) is
connected to the actuator (7), characterised in that the
transversal acceleration measuring device exhibits a first
transversal acceleration sensor for the measurement of the
transversal acceleration of the car body (1), which measures the
transversal acceleration in a first transversal direction
transversal to the car body longitudinal axis, and that the
transversal acceleration measuring device exhibits a second
transversal acceleration sensor for the measurement of the
transversal acceleration of the car body (1), which measures the
transversal acceleration in a second transversal direction
transversal to the car body longitudinal axis and transversal to
the first transversal direction.
2. The device according to claim 1, with at least two transversal
acceleration measuring devices, for the measurement of the
transversal acceleration at different points in the longitudinal
direction of the car body (1).
3. The device according to claim 1, with a position measuring
device for the measurement of a position of the car body (I) with
regard to at least one undercarriage (5), whereby the position
measuring device exhibits means for the measurement of the relative
position in relation to two degrees of freedom for movements
transversal to the car body longitudinal axis.
4. The device according to claim 3, whereby the position measuring
device exhibits a first transversal position sensor for the
measurement of the relative transversal position of the car body
(1), which measures the transversal position in a first transversal
direction transversal to the car body longitudinal axis, and
whereby the position measuring device exhibits a second transversal
position sensor for the measurement of the relative transversal
position of the car body (1), which measures the transversal
position in a second transversal direction transversal to the car
body longitudinal axis and transversal to the first transversal
direction.
5. The device according to claim 3, with at least two position
measuring devices for the measurement of the relative position at
different places and/or in different areas in the longitudinal
direction of the car body (1).
6. The device according to claim 1, whereby the minimum of one
actuator (7) exhibits a hydro-pneumatic device, with A container
(51), which exhibits a diaphragm (57) separating a chamber (53)
containing gas and a chamber (55) containing fluid, and a choke
(63), which chokes a volume flow into and/or out of the chamber
(55) containing the fluid from and/or to a storage vessel.
7. The device according to claim 1, whereby the device exhibits a
first actuator (7) and a second actuator (7), whereby the actuators
(7) are aligned and arranged in such a way that they can change the
transversal position of the car body (1) in a common transversal
direction, whereby the actuators (7) are in each case
antagonistically actuatable by the application of an operating
pressure and whereby the device exhibits means for the adjustment
and/or delimitation of the sum of the operating pressures.
8. A method for the position adjustment of a car body (1) of a
track-guided vehicle, in particular a rail vehicle, with regard to
at least one undercarriage (5) of the vehicle, whereby A
transversal acceleration of the car body (1) transversal to a car
body longitudinal axis is determined, and depending on the
transversal acceleration, a transversal position of the car body
(1) with regard to the minimum of one undercarriage (5) is
adjusted, characterised in that a first transversal acceleration of
the car body (1) is determined in a first transversal direction
transversal to the car body longitudinal axis and a second
transversal acceleration of the car body (I) is determined in a
second transversal direction transversal to the car body
longitudinal axis and transversal to the first transversal
direction.
9. The method according to claim 8, whereby the second and/or at
least a higher temporal derivation of the first and/or second
transversal acceleration of the car body (1) is formed, and,
dependant on this, the transversal position of the car body (1) is
adjusted.
10. The method according to claim 8, whereby the first and/or
second transversal acceleration of the car body (1) is determined
for at least two different places and/or areas in the longitudinal
direction of the car body (1), and, dependent on this, the relative
transversal position of the car body (1) is adjusted at two
different positions in the longitudinal position of the car body
(1).
11. The method according to claim 10, whereby, from the determined
values of the transversal accelerations of the car body (1), at the
minimum of two different places, a turn acceleration of the car
body (1) about a high axis is calculated.
12. The method according to claim 10, whereby, from the determined
values of the transversal accelerations of the car body (I), at the
minimum of two different places and/or areas, the first and/or at
least one higher temporal derivation of a turn acceleration of the
car body (1) about a high axis is calculated, and, dependent on
this, the relative transversal position is adjusted at two
different places in the longitudinal direction of the car body
(1).
13. The method according to claim 8, whereby, with regard to the
relative transversal position of the car body (1), frequency ranges
are considered and influenced with a frequency less than or equal
to 10 Hz, in particular less than or equal to 7 Hz.
14. The method according to claim 8, whereby, with regard to the
relative transversal position of the car body (1), frequency ranges
are considered and influenced with a frequency less than or equal
to 4 Hz, in particular less than or equal to 2 Hz, and whereby the
transversal acceleration of the car body (1) is evaluated in a
frequency range with a higher frequency and is taken into
consideration during the adjustment of the relative transversal
position.
15. The method according to claim 1, whereby, during a
determination of a manipulated variable for the adjustment of the
relative transversal position of the car body (1), at least one
characteristic of the movement behaviour of the car body (1) is
taken into consideration, in particular a characteristic for the
excitation of oscillations of the car body (1), and whereby, by
repeated evaluation of measured values and by temporal
extrapolation of the movement behaviour of the car body (1), a
possible future movement state of the car body (1) is calculated
and taken into consideration in the determination of the
manipulated variable.
Description
[0001] The invention relates to a device and a method for the
position adjustment of a car body of a track-guided vehicle,
particularly of a rail vehicle, with regard to at least one
undercarriage of the vehicle.
[0002] During the operation of rail vehicles, as a result of
irregularities and defects in the rail alignment and rail position,
undesirable transversal movements occur, which are detected as
disturbing by passengers in particular. With undercarriages with
conventional passive spring and damping systems, when travelling
around a curve this leads to further deterioration in comfort,
because the car body is displaced outwards transversal to the
direction of travel or its longitudinal direction respectively, and
the transversal suspension is therefore working in an area with
higher spring rigidity.
[0003] To overcome these disadvantages with purely passive devices,
active and adjustable systems have been proposed which counteract
the transversal displacement. Known positioning devices, which are
located between the undercarriage and the car body, exert a force
on the car body which takes effect laterally during travel around
bends in a track, which move it in the direction of the middle
position in relation to the undercarriage. As a result, the full
spring travel of the transversal suspension is again available, and
stop elements on side buffer elements which delimit the transversal
travel available are largely avoided. In order to achieve a high
transversal elasticity of the coupling between the undercarriage
and the car body, pneumatic actuators with high elasticity are used
as positioning devices, for example. A disadvantage here is a large
structural volume.
[0004] From DE-OS 20 40 922 the principle is known of regulating
the position of a car body in relation to two undercarriages
arranged on the end side in the direction of travel. In this
situation, transversal acceleration sensors in the end areas of the
car body detect the transversal acceleration values and, depending
on these values, actuators control the relative position of the car
body in relation to the undercarriages.
[0005] A problem of the invention is to increase the travel
comfort.
[0006] The present invention is based on the knowledge that it is
not sufficient, for a high degree of travel comfort, for only the
transversal acceleration of a car body to be detected in one single
direction and, depending on this, for the transversal position of
the car body to be adjusted relative to an undercarriage. If the
car body undergoes a transversal acceleration in an approximately
horizontal direction, as a result of a fault in the track position,
for example, in most cases there will be a simultaneous wobbling
movement of the car body, i.e. a rotational movement will be
incurred about a longitudinal axis of the car body pointing
approximately in the direction of travel. Formulated in general
terms, the car body has more than one degree of freedom for
movements transversal to its longitudinal axis. If only the
acceleration in a transversal direction is detected, acceleration
movements which are felt as disturbing in transversal directions
other than the transversal direction detected cannot be compensated
for.
[0007] Added to this is the fact that, due to the resetting of the
car body into a middle position relative to the undercarriage,
additional wobble movements, in particular oscillations, can be
incurred. This applies in particular for the usual situation in
which an actuator for adjusting the transversal position of the car
body is arranged beneath the car body floor, and therefore far
beneath the car body centre of gravity.
[0008] With known systems which measure the transversal
acceleration in one transversal direction only, it was not possible
for active engagement to be effected in such frequency ranges which
are appreciated as particularly disturbing, because the wobbling
movements referred to earlier can precisely then be excited in
resonance. If no information is available with regard to the wobble
movement, the only possibility which remains is not to intervene at
all in the critical frequency ranges. The range of frequencies in
which it was hitherto possible to make an active intervention lay
perceptibly below 1 Hz.
[0009] It is possible that other oscillations may occur as well as
wobble movement oscillations, in particular in an approximately
horizontal direction, and/or turning movement oscillations, i.e.
about a height axis of the car body. It is known that oscillations
in a specific frequency range, mostly about 3 Hz, will be sensed by
persons in the car body as particularly disturbing, while by
contrast oscillations with greater and/or smaller frequencies will
not be felt as equally disturbing. A further finding of the
invention is that it is felt as particularly disturbing if
oscillations occur in different directions and/or rotational
oscillations about different axes, and if these oscillations
exhibit different frequencies. It is possible, on the basis of the
invention, for oscillations with such disturbing frequencies and/or
frequency combinations to be damped and/or to be avoided.
[0010] The invention enables greater travel comfort to be achieved,
in that the transversal acceleration is determined in at least two
different directions transversal to the car body longitudinal axis.
For example, the transversal acceleration is determined in a first
transversal direction, which, if the vehicle is travelling in
undisturbed straight travel, lie in the horizontal plane, and the
transversal acceleration is additionally determined in a second
transversal direction approximately perpendicular to the first.
Transversal acceleration sensors which can be used for this are
known. In particular, the absolute transversal acceleration is
determined. The term "absolute" is understood to mean that the
transversal acceleration is determined in relation to an inertial
system. It is not mandatory that all the components of the
acceleration to be determined.
[0011] In particular, the incitement of a wobble movement can be
directly determined. In addition, the substantially more precise
knowledge of the movement state of the car body allows for a
leading calculation, i.e. a calculation which can be extrapolated
into the future.
[0012] In a preferred embodiment of the method according to the
invention, in addition to this, with a determination of a
manipulated variable for the adjustment of the relative transversal
position of the car body, at least one characteristic of the
movement behaviour of the car body is taken into account, in
particular a characteristic for the excitation of oscillations of
the car body, and/or due to the repeated evaluation of measured
values and by temporal extrapolation of the movement behaviour of
the car body, a possible future movement state of the car body can
be calculated and taken into account when determining the
manipulated variable. The taking into consideration of information
relating to the movement behaviour of the car body does indeed
require as a precondition the single acquisition and input of the
minimum of one characteristic value (e.g. a static or dynamic
value) for the movement behaviour, but also makes a high degree of
travel comfort possible. The term "characteristic" is also
understood to mean a parameter for a control algorithm, by means of
which the movement behaviour is taken into account, and in
particular the coupling of different oscillation movements. With
regard to the initiation of a wobble movement, tests and
simulations have shown that it is sufficient to use one or more
actuators, which allow for an adjustment of the relative
transversal position of the car body in one transversal direction
only, such as the horizontal direction, for example, in undisturbed
straight-ahead travel. A regulating system according to the
invention can avoid the excitation of an oscillation movement about
the longitudinal axis of the car body, e.g. by way of corresponding
repeated adjustment of the transversal position in an approximately
horizontal direction. In particular, changes in the transversal
position in respect of the frequency and/or amplitude will be
avoided, which would excite a resonance oscillation of the car
body.
[0013] In one embodiment of the method, frequency ranges are
considered in relation to the relative transversal position of the
car body, and influenced by frequencies less than or equal to 10
Hz, in particular less than or equal to 7 Hz. This accordingly
avoids even higher frequency ranges, in which the risk pertains
that a peaceful run behaviour of the chassis will be impaired. In
addition to this, in this way energy is also saved in relation to a
higher-frequency regulating arrangement.
[0014] For preference, frequency ranges are considered in relation
to the transversal position of the car body and influenced with a
frequency less than or equal to 4 Hz, in particular less than or
equal to 2 Hz, and the transversal acceleration of the car body is
evaluated in a frequency range with a higher frequency and taken
into account in the adjustment of the relative transversal
position. This makes it possible for a rapid reaction to be
achieved in comparison with previously-known solutions in response
to deflections of the car body in the transversal direction, in
particular due to entering a curve. Nevertheless, by the
consideration of the transversal acceleration in a higher frequency
range, high oscillation amplitudes in this higher frequency range
can be avoided. In particular, this frequency range is a range in
which oscillations, e.g. in accordance with an ISO Standard, are
classified as particularly disturbing or undesirable. The
separation of the frequency ranges for the consideration or
evaluation of the transversal position and the transversal
acceleration makes it possible for a stable regulation to be
achieved both with regard to the avoidance/damping of oscillations
as well as with regard to the regulating of the transversal
position.
[0015] In one embodiment, the transversal acceleration of the car
body is determined for at least two different positions and/or
areas in the longitudinal direction of the car body, and, depending
on this, the relative transversal position of the car body is
adjusted at two different positions in the longitudinal direction
of the car body. This makes possible in particular the regulating
of a turning movement (yawing movement) of the car body about a
height axis (e.g. an axis running in the vertical direction). To do
this, it is possible for a turning acceleration of the car body
about the height axis to be calculated from the determined values
of the transversal accelerations of the car body at the minimum of
two different places, and for this to be taken into account during
the adjustment of the relative transversal position(s) of the car
body. This enables travel comfort to be increased still
further.
[0016] It is particularly preferred for the second and/or at least
one higher temporal derivation of the transversal acceleration of
the car body to be formed, and for the transversal position of the
car body to be adjusted as a function of this. The transversal
acceleration of the car body itself, and its first derivation, are
less well-suited for the adjustment of the transversal position,
because both a temporal constant transversal acceleration as well
as a temporal constant first derivation in travelling around curves
can be formed on the basis of the track keeping or track guiding.
It is nevertheless also possible, in particular outside travel
around curves, for the transversal acceleration and/or its first
derivation to be used.
[0017] Accordingly, it is preferred, for a regulation of the yaw
movement of the car body, for the first derivation and/or at least
one higher temporal derivation of a turning acceleration of the car
body, from the values of the transversal accelerations of the car
body determined at least at two different places and/or areas in
the longitudinal direction of the car body, to be calculated about
a height axis and, depending on this, for the relative transversal
position to be adjusted at two different positions in the
longitudinal direction of the car body.
[0018] Depending on the manipulated variable which is calculated
for the adjustment of the transversal position(s) of the car body,
it may be favourable, for reasons of regulating technology, for a
still higher stage of derivation to be used. For example, the
manipulated variable could be a volume flow of a hydraulic valve,
which controls the flow of a hydraulic fluid into and/or out of a
hydraulic device. In this case, a constant volume flow corresponds
to a sustained change in the relative transversal position. The
control device accordingly exhibits an integrated behaviour, which
to the purpose should be jointly taken into account during the
regulating.
[0019] In particular, the transversal position of the car body can
have a middle position, relative to the minimum of one
undercarriage, for the straight-ahead travel of the vehicle. It is
not mandatory for the car body to be reset into the middle position
when travelling around curves. The regulating arrangement can
detect, for example, that a complete reset is not favourable for
travelling comfort. It may even be desirable for a complete reset
to be avoided, in order to save energy for the adjustment work.
[0020] As a result of a regulating arrangement which reacts swiftly
and/or dampens and/or prevents oscillations, the transversal spring
attenuation can be designed quite generally as softer, because the
risk of an impact against end stop elements, which delimit the
possible transversal travel path, is reduced. The vertical spring
attenuation between car body and undercarriage in many cases also
fulfils the function of transversal spring attenuation. Air springs
between the car body and the undercarriage are particularly
comfortable, but contribute to the transversal attenuation with
reduced spring force. One advantage of such a regulating
arrangement therefore lies in the fact that soft air springs can
also be used for a vertical spring attenuation between the car body
and the undercarriage. Conversely, the regulating system needs to
react less frequently and/or less strongly in response to
interferences or impacts which are incurred.
[0021] An actuator for the adjustment of the relative transversal
position between the car body and the undercarriage exhibits, for
example, a hydro-pneumatic device with a container, which exhibits
a diaphragm separating a chamber containing a gas and a chamber
containing a fluid, and with a choke which chokes a volume flow
into and/or out of the chamber containing the fluid from and/or to
a storage vessel. Such an actuator can be drawn on to provide
spring attenuation of impacts in the transversal direction which
are initiated via the undercarriage.
[0022] In some cases, it is desirable to use not only one actuator
to adjust a relative transversal position of the car body. For
example, due to technical design reasons in some cases the actuator
can only be arranged in such a way that, when it is actuated, a
torque moment takes effect between the car body and the
undercarriage. It is therefore proposed that a device for the
adjustment of the relative transversal position should exhibit a
first actuator and a second actuator, whereby the actuators are
aligned and arranged in such a way that they can change the
transversal position of the car body in a common transversal
direction, whereby the actuators can in each case be actuated to
take effect against each other by the application of a working
pressure, and whereby the device exhibits means for the adjustment
and/or delimitation of the sum total of the working pressures.
[0023] In addition to the measurement described above of the
absolute transversal acceleration(s), it is proposed that the
position of the car body relative to the undercarriage or
undercarriages also be measured. In particular, the device for
adjusting the relative transversal position can exhibit a position
measuring device for the measurement of a position of the car body
relative to the minimum of one undercarriage, whereby the position
measurement device exhibits means for the measurement of the
relative position in relation to two degrees of freedom for
movements transversal to the car body longitudinal axis.
[0024] In particular, the position measuring device can exhibit a
first transversal position sensor for the measurement of the
relative transversal position of the car body, which measures the
transversal position in a first transversal direction transversal
to the longitudinal axis of the car body, and the position
measuring device can exhibit a second transversal position sensor
for measuring the relative transversal position of the car body,
which measures the transversal position in a second transversal
direction transversal to the longitudinal axis of the car body and
transversal to the first transversal direction.
[0025] In addition to this, the device can exhibit at least two of
the position measuring devices for the measurement of the relative
position at different positions or in different areas in the
longitudinal direction of the car body.
[0026] It is also proposed, by the combination of fast-working
hardware and intelligent software, that the transversal
accelerations and turning accelerations occurring on the car body
be reduced independently of one another, whereby common actuators
can be used for the adjustment of the transversal position(s).
[0027] A special expression of this invention is a regulating
arrangement which is adapted to the hardware structure, which takes
account of the link between wobble and transversal movement and in
this way allows for the regulation of the transversal movement in
respect of the minimisation of the car body transversal
acceleration and the transversal deflection of the car body at its
centre of gravity, as well as attaining a stabilization of the
wobble movement. Without consideration of the linking of
transversal and wobble movement, which results in particular from
the design factor that the transversal actuators used do not take
effect in the direction of the centre of gravity of the car body, a
regulating arrangement of higher frequency in the sense of
transversal travel comfort, and in this case in particular in the
meaning of ISO Guideline 2631, necessarily leads to a build-up of
the wobble movement in such a way that stable regulation becomes
impossible.
[0028] One advantage of the regulating structure proposed
hereinafter is that not only can the car body be centred in the
transversal direction, and the car body transversal acceleration
minimised, but also a wobble movement of the car body can be
stabilized. In addition to this, a turning movement of the car body
can be influenced. To summarise, by way of example the following
properties or aims can be enumerated:
[0029] Low-frequency regulation of the transversal deflection of
the car body;
[0030] In comparison with that, higher-frequency regulation of the
car body transversal acceleration;
[0031] Stabilization of the wobble movement of the car body;
[0032] Low-frequency regulation of the turning movement of the car
body about a height axis;
[0033] In comparison with that, higher-frequency regulation of the
turning acceleration on the car body.
[0034] To provide further explanation of the invention, reference
is made hereinafter by way of example to the appended drawings. The
individual Figures of the drawings show, in a diagrammatic
representation:
[0035] FIG. 1 A front view of a car body located in a
spring-suspension manner on an undercarriage,
[0036] FIG. 2 The car body according to FIG. 1, after the induction
of a transversal disturbance,
[0037] FIG. 3 The representation according to FIG. 2, whereby parts
have been omitted for the sake of easier overview,
[0038] FIG. 4 A plan view of a car with two undercarriages and in
each case two antagonistically-arranged transversal actuators.
[0039] FIG. 5 A function view of the arrangement according to FIG.
4,
[0040] FIG. 6 A function view of a hydro-pneumatic actuator between
an undercarriage and the car body,
[0041] FIG. 7 A circuit arrangement in general principle of a
regulating arrangement for the adjustment of the transversal
position of a car body.
[0042] In the drawings the same reference figures designate parts
which are the same and functionally the same.
[0043] FIG. 1 shows a rail vehicle with a car body 1 and an
undercarriage 5. The undercarriage 5 exhibits two wheels 6. The
undercarriage 5 is connected to the car body 1 by means of a
right-side and a left-side secondary spring element 4, e.g. air
springs, for the attenuation and damping of shocks primarily in the
vertical direction. Air springs have transversal spring rigidity,
even if small, in the transversal direction, which ensures the
emergency running property of the system. Located on the
undercarriage 5 is a securing element 67 extending upwards. Located
on the car body 1 is a securing element 65 extending downwards.
Arranged between the securing elements 65, 67 is an actuator 7, by
means of which the relative transversal position of the securing
elements 65, 67, and therefore of the car body 1 and the
undercarriage 5 can be adjusted.
[0044] FIGS. 5a and 5b show diagrammatically, in the form of a
circuit diagram, components of a mechanical model of the connection
of the car body 1 to the undercarriage 5 and the undercarriage 5 on
a track 9. The connection between the undercarriage 5 and the track
9 is not considered in any further detail. Connected in series with
the actual actuator 7 is a spring element 7', which corresponds to
a rigidity of the secondary spring element 4 in the transversal
direction. The reference numbers 8 and 15 designate damping
elements for the damping of impacts between the car body 1 and the
undercarriage 5. The actuator 7 and the spring element 7' are,
according to FIG. 5a, secured at one end to the car body 1 and at
their other end to the undercarriage 5; they can, however, also
take effect in mechanical series connection between the
undercarriage 5 and the car body 1. To achieve symmetry of the
effective actuator forces, according to FIG. 4 two actuators 7 are
mirror-symmetrically arranged per undercarriage 5, lying
transversal to the car body longitudinal axis, in order to achieve
moment-free conduct of force at the securing element 65 oriented in
the vertical direction.
[0045] FIGS. 2 and 3 show that a transversal interference incurred
from the track 9 which is being travelled over, via the
undercarriage 5, takes effect also as an actively-engendered
actuator movement not only as a transversal displacement of the car
body 1 but also as a wobble movement and possibly also as a turning
movement of the car body 1. For the sensory acquisition of the
state of the car body 1 deriving from this, and the acquisition of
its centre of gravity (or of a point 2 on a longitudinal axis
through the centre of gravity), not only transversal position
sensors and high position sensors are used (not represented in the
figure) but also transversal acceleration sensors 30. The
transversal position sensors can be located at or in an actuator 7,
and detect the transversal position of the car body 1 in the area
of its floor, relative to the undercarriage 5 associated with it.
One transversal position sensor on each undercarriage unit 5 is
sufficient. One pair of high position sensors in each case are
arranged for preference in the area of both ends of the car body,
or in each case at one end of the car body on the right and left on
the two car body longitudinal side walls, and in each case, on the
right and left seen in the direction of travel, detect the vertical
distance between the car body 1 and the undercarriage unit 5
allocated to it in each case. The high position sensors can also be
integrated into the secondary spring elements 4, or interact with
them.
[0046] The two transversal acceleration sensors 30 are arranged in
the area of the longitudinal-side car body ends and detect the
transversal acceleration values of the car body 1 as it enters into
travel operation.
[0047] In the transversal direction, the actuators 7, which can
actively adjust the relative transversal position and can be
actuated by a computer 20, hold the car body 1. These actuators 7,
as shown in FIGS. 5a and 5b, in each case have a springing and
shock-absorbing property, and so connect the car body 1 to the
individual undercarriage 5 in each case. In this way, transversal
interferences from the rails are transferred gently into the car
body. To increase travel comfort, the actuators 7 then create
adjustment forces for the adjustment of the transversal position,
which is specified by the regulating software.
[0048] The actuators 7 are in particular hydro-pneumatic actuators,
as shown in FIG. 6 by the example of a single actuator 7. The
actuator 7 exhibits a container 51, with a diaphragm 57 arranged in
it. The diaphragm 57 subdivides the container 51 into a gas chamber
53, which contains a gas, and a fluid chamber 55, which contains
hydraulic fluid. The fluid chamber 55 is connected via a choke 63
to a pressure chamber 61 and a fluid connection 60. Hydraulic fluid
is conducted in a controlled manner via the fluid connection 60,
through a valve, not shown, into the actuator 7, or conducted away
from it. The choke 63 represents a fluid resistance, so that the
actuator 7 has a shock-absorbing effect. Corresponding to the fluid
pressure in the pressure chamber 61, the relative transversal
position between the car body 1 and the undercarriage 5 is adjusted
via a piston 59 and a piston rod 58, which engages at the securing
element 67.
[0049] As is shown in FIG. 4, arranged at each undercarriage 5 are
two actuators 7 of the same kind, taking antagonistic effect on
each other. With the same pressure in each case in the pressure
chamber 61 of the two actuators 7, the forces on the piston 59 are
compensated for. The relative transversal position is therefore
changed due to the introduction of a pressure difference. In order
to prevent damage to or destruction of the actuators 7, the sum
total of the pressures in the two pressure chambers 61 of the two
actuators 7 of the same undercarriage 5 is limited to a maximum
value.
[0050] In an alternative embodiment, however, provision is made for
only one actuator 7 or a plurality of actuators 7, not taking
effect against one another per undercarriage.
[0051] Hereinafter only one example is described for a sensor
arrangement. The intention is to determine:
[0052] The inertial, i.e. absolute car body transversal
acceleration and turn acceleration at the centre of gravity,
and
[0053] The relative transversal displacement of the car body at the
two bogies, as well as its relative turn and wobble angle.
[0054] Because a direct measurement of the transversal displacement
of the car body centre of gravity is not practicable, several
measured values are drawn on (see FIG. 2 and FIG. 3).
[0055] In the first step, the relative wobble angle (p, of the car
body in relation to the front (v) and rear (h) undercarriage is
calculated from the relative transversal deflections
Y.sub.r.sub..sub.--.sub.v and Y.sub.r.sub..sub.--.sub.h of the
actuators, in which a path sensor is located in each case: 1 r =
r_v - r_h l v + l h
[0056] l.sub.v and l.sub.h are the distance intervals between the
actuators in the longitudinal direction of the centre of
gravity.
[0057] By analogy with this, the turning acceleration
[0058] {umlaut over (.psi.)}
[0059] can be determined with the aid of two transversal
acceleration sensors on the car body. With two points, in each case
the second temporal derivation of values is designated as: 2 = v -
h l v + l h
[0060] In the next step, the relative wobble angle w is determined
from the measured values of the vertical relative position Z.sub.r
is determined at the secondary spring elements, taking into
consideration the transversal distance interval
l.sub.q.sub..sub.--.sub.v between the path sensors. The indices vr
and vl mean "front right" and "front left". 3 w = z r_vr - z r_vl l
q_v
[0061] The measurement can be checked by adding vertical path
sensors at the rear bogie.
[0062] Next, the relative transversal position Y.sub.r of the car
body is calculated from the relative deflections of the actuators
and the two relative wobble and turning angles determined
heretofore (FIG. 7). 4 r = y r_v + r_h 2 - z w - r l v - l h 2
[0063] Z is in this situation the arithmetical mean value of the
vertical relative positions right and left.
[0064] The car body transversal acceleration can be determined by
analogous considerations. Two transversal acceleration sensors
secured to the car body provide the car body transversal
acceleration at the centre of gravity, when the portions resulting
from the wobble angle and the wobble acceleration and turn
acceleration of the car body have been adjusted.
[0065] Next, the absolute wobble acceleration is determined by
means of vertical acceleration sensors secured to the car body.
Vertical acceleration sensors at the rear part of the car body can
support the measurement.
[0066] Account is further taken of the fact that the acceleration
due to gravity provides an element to the measured transversal
accelerations on the car body, above the absolute wobble angle of
the car body, which means that, by applying an approximation of the
absolute wobble angle, the car body transversal acceleration can be
determined by way of a relative wobble angle filtered through a
low-pass filter.
[0067] In addition to this, a pressure sensor is provided per
actuator, in order to regulate the two antagonistic actuators of
the each undercarriage with regard to the sum total of the
pressures in the actuators.
[0068] With the sensor arrangement described, a transversal
position regulation of the car body can be carried out. The aim of
this regulation is to carry out the transversal position regulation
in such a way that no build-up of the wobble movement takes
place.
[0069] By way of example, the function of a regulation of the
transversal position is shown in FIG. 7.
[0070] Because a constant transversal acceleration should not be
used, but also not the almost constant first derivation of the
transversal acceleration arising on curves, the transversal
acceleration regulation must therefore use signals which contain
the second and/or at least a higher temporal derivation of the
transversal acceleration of the car body centre of gravity, or from
which these can be derived.
[0071] An advanced calculation for the stabilization of the wobble
movement takes place for preference by the use of at least two
different derivations of the transversal acceleration of the car
body centre of gravity. The determination of these derivation
signals is effected in particular by means of a regulating
technology filter with an order which is greater than the order of
the maximum derivation stage used. The order of filtering is
determined inter alia from the excitability of the car body in
response to oscillations, and depends on how close the frequency
range taken into account by the regulating arrangement lies to
frequency ranges in which oscillations can be excited. The closer
the range taken into account lies to the excitation range, and the
easier oscillations are excited, the higher the order of filtering
should be.
[0072] By analogy with this, the regulation of the turn
acceleration can be carried out separately. For preference, the
turn acceleration regulation does not make use of the turn
acceleration itself, if an actuator with integrating effect is
being actuated directly. It is therefore proposed that the first
derivation of the absolute turn acceleration of the car body centre
of gravity be used for the regulation.
[0073] In some cases in practice, no advance characteristics
analogous to the transversal acceleration regulation are necessary
with regard to the turning movement, and therefore additional
higher temporal derivations of the turn acceleration do not
necessarily have to be taken into account. With rail vehicles this
is due, for example, to the fact that, due to the regulation, the
risk does not arise of the excitation of oscillations of the car
body. A filter of a smaller order is therefore adequate. Higher
derivation stages can be used optionally, however, which in turn
correspond to filters with higher orders.
[0074] Position regulation procedures regarding the transversal
deflection of the centre of gravity of the car body and the turning
angle of the car body with regard to the bogie can make use of an
integrating effect of an actuator and therefore use only a P
(proportional) portion and a D (differential) portion, which is
likewise realised via a deep-pass filter of at least the second
order. An integral portion can likewise be used, but for preference
this has only a portion of regulator output signals typically
smaller than one tenth.
[0075] Taking into account the geometric circumstances, the
regulator output signals calculated in this way are distributed
onto actuators arranged on the car body in the longitudinal
direction almost at the end face. With hydraulically actuatable
actuators, for example, volume flows of a hydraulic fluid for at
least one actuator at the front (Q.sub.v) and one actuator at the
rear (Q.sub.h) on the car body are calculated and adjusted, which,
depending on the sign, are supposed to flow in or out, seen from
the actuator. If two actuators are antagonistically arranged, the
adjustment signal determined will be distributed with different
signs to the right and left actuators.
[0076] It may be required that the relative car body transversal
position should not be kept constant, but that the actuators should
stay in their middle setting even when travelling around curves. In
this way, the entire actuator path is always available in order to
be able to compensate for dynamic transversal interferences. In
this case, a reference signal for the car body transversal position
is calculated in such a way that this is guaranteed. Determinant in
this is the wobble angle of the car body derived as stationary from
the curve travel. This can be calculated by back-calculation.
[0077] This reference signal, as described on the basis of FIG. 7,
is low-frequency filtered and does not tale effect on a branch of
the regulating process which processes derivations of the
transversal acceleration. In this way, the reference signal is
processed at low frequency without negative effect on the
acceleration regulation.
[0078] A sum total pressure regulation of antagonistic actuators
(as described heretofore) can be added to the regulating structure
represented in FIG. 7. In this situation, the sum total pressure
which is determined from the two antagonistic actuators in each
case is used for the regulation. If the sum total pressure exceeds
or falls short of a reference value, then, for example, the oil
volume flow required for both actuators will be reduced or
increased in the same direction by a fraction which is proportional
to the deviation. The delimiting of the sum total pressure upwards
prevents the risk of destruction of the actuators. Delimitation
downwards guarantees stable regulation, which is not destabilized
by changing the properties of the actuators, in particular the
damping properties.
[0079] In particular, the reference transversal position of the car
body centre of gravity 2 is determined as a filtered product from
the wobble angle w and the distance interval h between the centre
of gravity 2 and the engagement point of the actuator 7 on the
securing point 65 (FIG. 3).
[0080] On the left in the upper block 70 in FIG. 7, the regulating
branch begins for the generation of a reference value Y.sub.rs for
a relative position of the car body centre of gravity in the
transversal direction. To do this, the wobble angle w is used as an
input variable; for example, during travel round a curve, the
actuator should adopt or retain a middle position so that the full
actuator path is available on both sides of the middle
position.
[0081] Signals derived from this are processed to form volume flow
control signals Q.sub.v for the hydraulic actuator 7 of the front
undercarriage 5 and Q.sub.h for the hydraulic actuator 7 of the
rear undercarriage 5, whereby these control signals control
hydraulic valves which are connected in supply lines between one or
more storage containers containing hydraulic fluid and the
individual actuators 7.
[0082] As a further input variable, the car body transversal
acceleration is conducted to an electric filter 81. The filter 81
delivers very small portions of the regulating output signals, both
for high-frequency as well as low-frequency parts of the
transversal acceleration oscillations measured or derived, for
preference very much smaller than 10%. As a result of this, the
oscillations are damped and/or prevented which are located in the
middle frequency range located in between (typically 3-5 Hz) and
which are perceived as being particularly interfering or are
defined or normed as such. In addition, in this way energy can be
saved for the adjustment of the actuators, since a regulating
procedure operating in a narrower frequency range requires less
energy, and, on the other hand, a more efficient regulator
intervention is guaranteed in the frequency range in which the
strongest negative effect on comfort is to be anticipated.
[0083] The regulating branch beginning in the left part of the
block 70 exhibits a multiplier designated with the reference number
71, which multiplies the input signal for wobble angle w by the
value h. h is the distance interval represented in FIG. 3 between
the actuator and the car body centre of gravity 2. The output
signal from the multiplier 71 is passed to a regulating element 73,
which is adjustable. It can be adjusted in such a way that the
regulating branch has no effect whatever, i.e. in particular when
travelling around curves, no resetting takes place of a change
incurred by centrifugal forces of the relative position between car
body and undercarriage. It can also be adjusted in such a way,
however, that such resetting is possible, or that the regulating
branch is active. An output signal from the regulating element 71
is conducted to a low-pass filter 75. The low-pass filter 75 has
the function of essentially making only the slow, i.e.
low-frequency, portions of the wobble movements of the car body
usable for the regulation procedure. For example, a disconnection
edge of the low-pass filter 75 can be set to a value of between 0.1
and 0.5 Hz. Available at the output of the low-pass filter 75 is
the reference signal Y.sub.rs for the relative position of the car
body. The reference signal Y.sub.rs is compared with the measured
value Y.sub.x in a differentiator element 89.
[0084] The differential signal is conducted to two electric filters
77 and 79, whereby the filter 77 delivers low-frequency signals
which are proportional to the deviation between the reference value
of the relative position of the car body centre of gravity and also
proportional to the first temporal derivation of the differential
signal. The filter 77 operates on a higher frequency than the
low-pass filter 75. As far as possible it has no integrating
effect. The filter 77, together with the filter 79, guarantees the
transversal position regulation of the car body. The filter 77 does
not deliver higher-frequency signals, in particular with a
frequency greater than 2 Hz, which therefore guarantees a stable
and reliable transversal position regulation.
[0085] The filter 79 has an integrating effect. The filter 79, like
the filter 77, contributes to the transversal position regulation
of the car body. The portion of the filter 79 is very small in
comparison with filter 77, however, and for preference constitutes
less than a tenth of the portion of the filter 77 in the regulator
output signal. The portion of the filter 79 is suitable for
eliminating an offset in the actuation of hydraulic valves. The
filter is also effective at lower frequency than the filter 77. The
output signals of the filters 77, 79, 81 are conducted to a summing
element 91, and so produce a sum signal, which in turn is conducted
to a summing element 93 and a differential forming element 95.
[0086] As is shown in the framed block 72 in FIG. 7 with the shaded
lower part, a turn acceleration signal is conducted to a further
filter 83, which delivers very small portions both for
higher-frequency portions as well as for lower-frequency portions
of the turn acceleration determined (for preference less than 10%
of the regulator output signals). As a result of this, by analogy
with the regulating described heretofore of the transversal
position, in the block 70 oscillations are compensated for in a
middle, particularly interfering range of, for example, 3-5 Hz.
Attention is drawn to the advantages described heretofore. In
addition to this, a signal corresponding to the turn angle which
has been determined is conducted to an electrical filter 85, and,
parallel to this, to a filter 87. Filter 85 delivers
lower-frequency signals, which are proportional to the relative car
body turn angle, and which are proportional to the first temporal
derivation of the angle. The filter contributes to the regulation
of the turn position of the car body. In the middle frequency
range, in which the filter 83 is particularly effective (see
above), or above this, no signals are delivered. Filter 87, like
filter 85, contributes to the adjustment of the turn position of
the car body. The portion of this filter in comparison with the
filter 85 should be very small (e.g. less than 10%) and is suitable
for eliminating an offset during the actuation of hydraulic valves.
The filter 87 is also effective at lower frequencies than the
filter 85.
[0087] Like the filters 77, 79, and 81, the filters 83, 85, 87
should not overlap in their effective frequency ranges, or as
little as possible, i.e. in the frequency ranges in which they
deliver effective portions for the regulator output signals.
[0088] The output signals from the filters 83, 85, and 87 are
conducted to a summing element 97, which is in turn conducted to
the summing element 93 and the differential forming element 95.
[0089] The summing element 93 issues the output signal Q.sub.v. The
summing element 95 issues the output signal Q.sub.h.
[0090] As an option, an amplifier can be provided for between the
summing elements 91, 97, and the summing element 93 or the
differential forming element 95 respectively, in order to take
account of the geometry and mass circumstances of the vehicle which
is to be controlled.
[0091] Overall, therefore, the situation is achieved in that, with
little effort in terms of measurement technology, the essential
factors are detected for a pleasant travelling sensation, and a
stable and jerk-free positioning of the car body in travel
operation. In particular, vibrations arising on the car body can
also be eliminated, and the excitation of a wobble movement of the
car body, which under certain circumstances derives from this, can
also be done away with. In addition to this, by taking account of
the connection between the wobble movement and the transversal
movement, a stabilization of the wobble movement can also be
achieved.
* * * * *