The present application relates to an electrically height-adjustable table and to a method for controlling the latter. In particular, the application also involves an apparatus and a method for detecting collisions in the case of an electrically height-adjustable table.
When moving a height-adjustable tabletop of a table up or down, collisions with obstacles, for example walls or objects, may arise, which can damage the table or the obstacle. It is also critical if persons or animals collide with the table, which can entail injuries, for example bruising. In order to reduce the risk of injury and damage, it is necessary to detect a collision with an obstacle in order to be able to take suitable measures, for example interrupt the movement of the tabletop after the collision or move the tabletop back.
EP 1 891 872 B1 discloses an apparatus and a method for detecting collisions in the case of furniture and relates, in particular, to an apparatus and a method for detecting collisions of automatically movable parts of furniture with obstacles by capturing a bending change. The known apparatus comprises a sensor which is adapted to capture a bending change of the movable part and contains a piezoelectric material and is a piezoelectric diaphragm for generating sound signals. A bending change of an attachment location of the movable part is captured by the sensor upon collision of the movable part with an obstacle by changing a compression or extension of the piezoelectric material in the event of the bending change of the location of the movable part and generating an electrical signal by means of the piezoelectric material when the compression or extension is changed.
EP 1 837 723 A2 describes a multipart piece of furniture having at least one electromotive drive which is provided for the purpose of adjusting a furniture part which can be moved in two opposite directions, wherein a control system comprises a safety device which is effective during adjustment of the furniture part and is provided for the purpose of preventing impermissible operating states, wherein the safety device is assigned an inclination sensor which is fitted to the movable furniture part and the output signal from which is evaluated by the safety device in order to detect an impermissible position of the movable furniture part. A capacitive acceleration sensor having a micro-mechanical sensor element can be used as the inclination sensor.
DE 20 2007 006 673 U1 relates to an electrically height-adjustable table comprising a height-adjustable base frame, a tabletop which is arranged on the base frame, at least one drive device for adjusting the height of the base frame/tabletops, in which the drive device is fastened to the base frame and/or the tabletop, wherein the drive device comprises at least one electric motor for the operation thereof, a control part for controlling the drive device and an operating device for activating the control part, wherein the table comprises a “tilt apparatus” which causes the stopping or the reversing and then stopping of the drive device if the table is inclined.
DE 10 2006 038 558 A1 relates to an arrangement for controlling the drive of an electrically adjustable piece of furniture. Said arrangement has a control device which is connected to at least one motor and to an operating device. Furthermore, at least one acceleration sensor arranged on the furniture is connected to the control device, and the control device is designed in such a manner that, in the event of an acceleration measured by the acceleration sensor, the at least one motor is controlled in such a manner that the movement of the furniture is stopped.
DE 10 2016 102 382 A1 relates to an electrically adjustable table and to a control method for the electrically adjustable table. The control method for the electrically adjustable table contains the following steps: initializing an internal setting or a user setting, entering a quiescent status, extending or retracting a table foot in order to adjust the height of a tabletop, which moves in a first direction, in accordance with an operation on a manual control apparatus, stopping the adjustment of the height of the tabletop if a motion sensor unit is used and detects that the table top is inclined during the adjustment of the height of the tabletop. The motion sensor unit is a gyroscope or an acceleration measuring sensor.
Finally, DE 10 2016 101 955 A1 discloses an electrically adjustable piece of furniture. The piece of furniture has an electrical drive motor for adjusting at least one furniture adjustment section with respect to a furniture carrier section, wherein the piece of furniture is provided with a sensor device for detecting the inclination or inclination change of the furniture adjustment section. The sensor device may comprise a gyroscopic sensor which can be used to determine the inclination or inclination or angle change of the furniture adjustment section. In addition, the sensor device may comprise a gravity sensor which can be used to determine the absolute inclination of the furniture adjustment section.
However, in the above-mentioned prior art, the sensor devices cannot be positioned in any desired orientation on an electrically height-adjustable table for correctly detecting collisions. This complicates assembly and therefore results in higher production costs.
The present invention is therefore based on the object of enabling any desired positioning of a sensor device for detecting a collision in an electrically height-adjustable table.
According to the invention, this object is achieved by means of an electrically height-adjustable table comprising: an electrically height-adjustable base frame, a tabletop which is arranged at or on the base frame, a drive device for adjusting the height of the base frame/the tabletop, wherein the drive device is fastened to the base frame or to the tabletop and comprises at least one electric motor, a control device and an operating device for operating the control device, and a sensor device for detecting an initial absolute inclination of the tabletop upon receiving an input of a movement command via the operating device and for detecting a subsequent absolute inclination and a subsequent temporal inclination change of the tabletop during the movement of the tabletop up or down according to the movement command, wherein the sensor device comprises a three-axis acceleration sensor for determining the absolute inclination of the tabletop and a three-axis gyroscope, preferably integral therewith, for determining the temporal inclination change of the tabletop, preferably wherein the acceleration sensor and the gyroscope are accommodated in a micro-electromechanical system (MEMS) component, wherein the sensor device also comprises a computing device, in particular a microprocessor, which, in order to determine the initial absolute inclination of the tabletop each time before executing an input movement command, is configured to cause initial capture of acceleration components by means of the acceleration sensor in a three-dimensional Cartesian coordinate system oriented on the basis of the installation orientation of the acceleration sensor and a comparison of the captured acceleration components with known acceleration components under the same conditions in a global three-dimensional Cartesian coordinate system, wherein the z-axis of said coordinate system is oriented in the direction of gravitational acceleration, and a possible offset correction of the captured acceleration components and a possible inversion of the acceleration component in the z direction and a conversion of the captured and possibly offset-corrected and/or possibly inverted acceleration components into an inclination angle or vector and, in order to accordingly determine an absolute inclination of the tabletop by capturing acceleration components by means of the acceleration sensor and in order to determine a temporal inclination change of the tabletop or a variable representative of the temporal inclination change of the tabletop during the subsequent execution of the movement command by capturing angular velocity components by means of the gyroscope, is configured to cause a possible inversion of the angular velocity components and a summation of the angular velocity components and a comparison of the determined sum of the angular velocity components with a predefined angular velocity limit value.
This object is also achieved by means of a method for controlling an electrically height-adjustable table as claimed in one of the preceding claims, comprising: receiving, at the operating device, an input of a movement command by a user, determining, in response to the movement command, an initial absolute inclination of the tabletop by means of the computing device by initially capturing acceleration components via the acceleration sensor in a three-dimensional Cartesian coordinate system oriented on the basis of the installation orientation of the acceleration sensor and comparing the captured acceleration components with known acceleration components under the same conditions in a global three-dimensional Cartesian coordinate system, wherein the z-axis of said coordinate system is oriented in the direction of gravitational acceleration, and possibly correcting the offset of the captured acceleration components and possibly inverting the acceleration component in the z direction and converting the captured and possibly offset-corrected and/or inverted acceleration components into an inclination angle or vector, and subsequently moving the tabletop up or down according to the movement command via the drive device, and determining an absolute inclination of the tabletop by capturing acceleration components by means of the acceleration sensor and determining a temporal inclination change of the tabletop or a variable representative of the temporal inclination change of the tabletop by means of the computing device during movement, wherein the temporal inclination change of the tabletop is determined by capturing angular velocity components via the gyroscope, possibly inverting the angular velocity components and summing the angular velocity components and comparing the determined sum of the angular velocity components with a predefined angular velocity limit value.
In the case of the table, provision may be made for the control device to be configured to stop the drive device or to control it in the opposite direction if the determined sum of the angular velocity components exceeds the angular velocity limit value, and/or wherein the control device is configured to stop the drive device or to control it in the opposite direction if the determined absolute inclination exceeds a predefined inclination limit value. This is because, if the sum of the angular velocities and thus the inclination change or the variable representative thereof exceeds the limit value, it is assumed that a collision has occurred, and a countermeasure is then taken.
Provision may also be made for the control device to be configured to control the drive device on the basis of the determined inclination or the determined temporal inclination change of the tabletop or the determined variable representative of the temporal of the tabletop.
According to a further particular embodiment, the sensor device can be fastened, preferably releasably, to the tabletop, preferably by means of adhesive bonding. For example, the sensor device can be fastened on or under the tabletop.
The sensor device is advantageously fastened, preferably releasably, in the operating device. For example, the sensor device can be fastened in a manual switch.
Alternatively, the sensor device can be integrated in the control device.
The operating device advantageously has a manual switch device.
According to a further particular embodiment of the present invention, the table has a display device which is configured to display the location and/or the magnitude of a determined inclination change. The term “magnitude” is intended to comprise the “absolute value”. If necessary, a direction of the inclination change can also be alternatively or additionally displayed on the display device. In this case, the term “determined inclination change” can relate both to the temporal inclination change (° /s) and to the change in the inclination (in °).
The table expediently has a database which is configured to store the location and/or the magnitude of a determined inclination change.
In this case, provision may be made, in particular, for the display device to be in the vicinity of or inside the operating device, in particular to be an integral part of the latter.
In the method, provision may be made for the method to comprise stopping the drive device or controlling the drive device in the opposite direction if the determined sum of the angular velocity components exceeds the angular velocity limit value, and/or stopping the drive device or controlling the drive device in the opposite direction if the determined absolute inclination exceeds a predefined inclination limit value.
In addition, provision may be made for the method to comprise controlling the drive device, by means of the control device, on the basis of the determined inclination or determined temporal inclination change of the tabletop or determined variable representative of the temporal inclination change of the tabletop.
The method may also comprise displaying, by means of the display device, the location and/or the magnitude of a determined inclination change of the tabletop.
Finally, the method advantageously comprises storing, by means of the database, the location and/or the magnitude of a determined inclination change of the tabletop.
The present invention is based on the surprising realization that any desired positioning and orientation of the sensor device on the electrically height-adjustable table is possible by combining a three-axis acceleration sensor with a three-axis gyroscope and, if necessary, correcting the measurement data on the basis of the installation orientation of the sensors—can also be mathematically referred to as coordinate transformation. The “coordinate transformation” is carried out in this case in an upstream initialization process. In said initialization process, the actual installation direction(s) of the sensor device or sensors is/are determined indirectly and the measured values for the inclination are then corrected on the basis of the actual installation direction(s). The sensor device can even be positioned without a tool, at least in a particular embodiment.
On the basis of an absolute inclination determined during initialization, common acceleration sensors can usually measure from approximately 0.5° owing to their design.
The gyroscope can be used to determine a fast inclination change, such as during a collision. A “fast” inclination change is intended to mean here an angular velocity of ≥1° /s (sum of all sensors). For example, sensor data can be captured every 10 ms and can possibly be converted and compared before a decision is made. In addition, the data can then be deleted for new measurements.
Further features and advantages of the invention emerge from the accompanying claims and the following description in which a plurality of exemplary embodiments are explained in detail on the basis of the schematic drawings, in which:
In the embodiment shown here, the sensor device 72 is located in the manual switch 71. As a result, there is no need for a separate housing for the sensor device and there is also no need to provide a further plug connection on the control device. As is intended to be expressed by the coordinates y′ and x′ in
More precisely,
If the limit value, here an angular velocity limit value in this example, is not exceeded, a check is also carried out in order to determine whether the tabletop has reached the target position according to the movement command (step 756). If so, the tabletop is stopped (step 758). If not, the tabletop is moved further according to the movement command (step 753).
In the case of the exemplary electrically height-adjustable table 10 shown in
More precisely,
The angular velocities determined by means of the gyroscope are no longer specifically added for this type of evaluation, but rather are considered individually (signs) depending on the sector. Therefore, it is necessary to integrate the sensor device in a known positioned system (global coordinate system 741) (X, Y, Z) (also see
The features of the invention disclosed in the above description, the drawings and the claims can be essential to the implementation of the invention in its various embodiments both individually and in the arbitrary combinations.
Filing Document | Filing Date | Country | Kind |
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PCT/DE2018/100073 | 1/31/2018 | WO | 00 |