Drive system, spring cradle system and method for simulating an elastic tensioning element

Abstract

Drive system (2) for a cradle system (100), in particular for a child's or baby's cradle, for generating an oscillating movement, comprising: a tension element (4) having a distal end which is designed to be attached to a vibrating element, a drive unit (21) configured to increase and decrease a free length of the tension element (4) in order to change a position of the oscillating element relative to the drive system (2), and a control unit (22) which is designed to control the drive unit (21) such that a pretensioning force acts on the tension element (4) independently of the position of the oscillating element relative to the drive system (2), wherein the control unit (22) is designed to drive the drive unit (21) in such a way that a mechanical clamping element is simulated, and wherein the drive system (2) comprises at least one resilient element (3) which connects the drive system (2) to the oscillating element.

Description

The present invention relates to a drive system for a spring cradle, a spring cradle system and a method for simulating an elastic tension element.There are numerous spring cradles preferred for infants and children. Usually, such a spring cradle usually consists of a reclining device similar to a stretcher which is fastened to a spring suspension. The spring suspension is connected via an elastic oscillation element, usually a spring, to a suspension which is suspended in a freely oscillating manner on a frame or another holder such as a door frame, etc. A load-bearing drive system is usually mounted on this suspension. The drive system comprises an electric motor which periodically applies a tensile force to the spring suspension via a traction body and thus sets the support in an upward and downward swinging movement.In known spring cradles, the drive system is connected to the spring suspension via the tension body, wherein the tension body is permanently held under tension. This is necessary in order for the drive system to receive information about the spring-in and spring-out movement, in order to apply the tensile force in the ascending spring movement, for example, and to apply no force in the descending spring movement. Since the swing amplitude varies depending on installed spring, weight (child plus stretcher, plus accessories, etc.) and applied force, the pulling body is equipped with a mechanical tension member to cause the pulling body to be permanently tensioned. This clamping element is usually implemented as a helical spring on the drive shaft of the motor. The clamping element ensures that the traction body is connected to the drive system continuously, independently of the deflection of the spring, despite variable distances which result from the weight of the child or of the stretcher, the installed springs, the amplitude intensity depending on the drive energy, etc. This ensures that a sensor, such as a servomotor or dynamo, can record information about the oscillation speed and direction and can thus control the energy for amplifying or maintaining the oscillation movement.The problem with this construction is that the mechanical clamping element does not allow for noiseless operation of the drive system. In practice, partial loudnesses of up to 63 db (A) are generated by the drive system.EP 3 197 323 B1 relates to a device for generating a rocking movement on supports for infants, comprising a frame arranged on a base and having a support arm and a traction means which is designed for suspending the support.DE 10 2018 006 463 A1 relates to a spring cradle which is suspended from an elastic element and is set in vibration by an eccentrically rotating mass.DE 11 2018 007 533 T5 shows an energy compensation device with a traction cable which is connected to a cable winding drum and a weighing mounting frame. Furthermore, the energy compensation device has a compensation driver which can control the cable winding drum such that the traction cable is wound onto the cable winding drum.GB 22 40 068 A discloses an apparatus and a mechanism for effecting a reciprocating movement for a cradle or the like. The device comprises a vertical rocker cradle connected to a traction element with a cylindrical drum. The tension element can be wound onto the cylindrical drum, so that the vertical rocker cradle is moved upward and downward. As a result, an oscillatory movement can be exerted on a cradle. DE 19848962 A2 shows a rocking device in which the rocking vibration is applied to the rocking device by means of one or more drives.However, the above problem is neither addressed nor solved in the prior art. Therefore, the present invention has as its object to provide a spring cradle driving system, a spring cradle system and a method for simulating an elastic tension member, which solve the above problem.The object is achieved by a drive system for a spring cradle having the features of claim 1, a spring cradle system having the features of claim 10 and a method for simulating an elastic clamping element having the features of claim 12.According to one aspect of the present invention, a drive system for a spring cradle system, in particular for a child or baby spring cradle, for generating a swinging movement is provided, comprising:a tension member having a distal end configured to be attached to a swing member,a drive unit configured to increase and decrease a free length of the tension member to change a position of the swing member relative to the drive system; anda control unit configured to control the drive unit such that a biasing force acts on the tension member regardless of the position of the swing member relative to the drive system.Accordingly, a spring cradle drive system is provided that operates without a mechanical biasing element. Consequently, operation of the drive system is possible almost silently. Furthermore, durability is thereby increased, since fewer mechanical components are used. According to one embodiment, the functionality of a mechanical clamping element can be algorithmically mimicked via microcontroller-controlled actuation of the drive unit.The drive system includes a drive unit, such as a rotating shaft electric motor. By rotation, the tension element, such as a cable, can be wound up via this shaft, as a result of which a tension force is transmitted by the tension element in the direction of the drive system. Thus, for example, the oscillating element can be moved in the direction of the drive system. In this case, the tension element can be rolled up onto a roller which is located on the shaft of the drive unit. If the drive unit is not in operation and the oscillating element moves away from the drive system, the tension element can roll off the roller, so that the shaft of the drive unit rotates in the opposite direction. Thus, the free length of the tension element (i.e. the part of the tension element corresponding to the distance between the drive system and the oscillating element) can be varied. By varying the free length of the tension element, a vibration of the vibration element can be initiated. An oscillating movement carried out by the oscillating element can be a movement whose sequence repeats in the same or very similar form periodically or according to predefined movement patterns, in particular complex movement patterns.The tension element may be a band-like element, such as a cable or a cord, configured to support the swing element together with a person accommodated therein. A proximal end of the tension element can be connected to the roller or be in engagement with it, so that the tension element is held on the roller even if the tension element no longer wraps around the roller. The distal end of the tension element can be the end of the tension element opposite the proximal end, which is connected or connectable to the oscillating element. A portion (i.e., a certain length portion) of the tension member that is not wound around the roll may define the free length of the tension member.The drive unit can be an electric motor, generates a rotational movement by supplying current and passes it on to a roller, for example, by means of a shaft. The direction of rotation of the electric motor can be varied. For example, the drive unit may have sensors which measure the current applied to the drive unit and thus can provide information about the operation of the drive unit. Further, the rotational energy output from the drive unit may be measured. Thus, by supplying the drive unit with a predetermined current and determining an output of the drive unit, the control unit can determine whether or not the tension member is connected with tension to the swing member. The prestressing force can thus be determined by a defined power supply (for example by applying a certain voltage) of the drive unit.The oscillating element can consist of a stretcher for receiving at least one person and a suspension device on which the stretcher is suspended.The control unit can ensure, by actuating the drive unit, that the tension element is always connected to the oscillating element under tension. For this purpose, a sufficiently high minimum force (prestress) can be applied to the tension element, which pulls the tension element toward the drive system (i.e. applies a torque to the shaft, such that the roller is rotated until the tension element is connected to the oscillation element under tension). The minimum force can be lower than the weight force of the oscillating element without the person accommodated therein. As soon as no movement of the tension element is detected any longer, the tension element is "under tension" and produces a direct connection of the oscillating element to the drive unit. The further application of a bias voltage is then no longer necessary, which is why the drive unit can be switched off. The drive system is thus in the idle state. The control unit can thus simulate the mechanical tensioning element which is used to maintain the tension of the tension element in the case of known spring cradles. Whereas in a mechanical tensioning element the tensile force, however, has a damping effect on a downward oscillating movement of the oscillating element and has to be compensated by a drive energy, the control unit of the drive unit generates a prestressing force (tensile force) for maintaining the tension of the tension element only if this is necessary. Therefore, the drive system of the present invention can be operated more efficiently.As soon as the control unit registers a movement of the tension element and the system is in the idle state, the control unit can control the drive unit such that the prestress is applied to the tension element. As a result, a direct connection of the tension element to the oscillation element can be ensured. This is advantageous, for example, if a person is loaded into a device on the oscillating element suitable for this purpose.As soon as the control unit determines that the oscillating movement moves away from the drive system, the drive unit can be controlled in such a way that no prestress is exerted any longer on the traction element. Otherwise, the drive unit would generate a force counter to the direction of oscillation, which would have a negative influence on the electronics and the energy consumption.The control unit may comprise a single board computer provided with a standardized operating system such as Linux so that any standard components can be connected. For example, the control unit can have a standardized interface such as a USB connection, an SD card reader or the like. Furthermore, access for the provision of plugins can be provided for developers in order to provide further functionalities of the drive system with these standard components. Thus, the control unit can be provided with further control sequences in order, for example, to execute individual vibration patterns.The drive system can have a single-track cable pulley with which the tension element can be wound and unwound. Because of the single-track cable pulley, the tension element can be prevented from skipping, as could occur, for example, in the case of an uncontrolled multi-track cable pulley. Accordingly, noise and vibrations during operation are prevented by uncontrolled jumping of the tension element (for example of a cable) on the pulley, and reliable operation of the drive system can be ensured. Alternatively, it is conceivable to provide a cable pulley with a guided track in conjunction with a cable guide, which leads to a constant torque and also improves the measurement accuracy via a possible rotation sensor, since the rotation speed remains almost constant independently of the length of the tension element. Consequently, a constant force can be transmitted from the drive unit to the traction element and vice versa. Accordingly, a particularly uniform operation of the drive system can be ensured.According to an aspect of the present invention, the drive system may comprise a powerful motor as the drive unit in conjunction with a guided track for the traction element, a guide for the traction element and a mechanical lock, and a recuperation device. A spring cradle system can thus also be realized without an elastic oscillation element. Thus, the aesthetic appearance of the spring cradle system can be improved, yet provide the same functionalities as with the resilient rocker element.Furthermore, the drive system can have a mechanical lock which can prevent the deflection of the tension element. Thus, the distal end of the tension member can be prevented from being displaced. Consequently, the distance between the driving system and the oscillating element can be kept constant irrespective of the load applied to the oscillating system. This is advantageous, for example, when a child or baby is being loaded into or removed from the oscillation system.According to a further aspect of the present invention, the drive system can be designed to carry payload by the drive system being suspended on a fixed holder and in turn a vibrating element (e.g. a payload device) being suspended via at least the traction element. Preferably, in addition to the tension element, a resilient element (e.g. an elastic element) is provided between the oscillating element and the drive system. Alternatively, the drive system may be designed to be non-payload-bearing. In this case, the drive system can be placed, for example, on a frame and connected to the oscillating element via the tension element. In this case, the oscillating element can be fastened to a frame or another device directly or indirectly (e.g. via an elastic element).Preferably, the drive system is arranged above (in relation to the direction of gravity) the oscillating element, so that the prestressing force is applied to the tension element in the opposite direction to the gravity. Nevertheless, the drive system can also be provided below the oscillating element, so that the prestressing force is applied to the tension element in the direction of gravity.According to one aspect of the present invention, longevity can be provided by dispensing with mechanical sensor systems. For example, only non-mechanical sensors may be used to determine a position of the oscillating element relative to the drive system. By using a microcontroller-based, intelligent control, an energy-optimized oscillation movement can be realized, since no mechanical sensor system dampens the oscillation movement and only minimal friction losses exist. the intelligent control of the control unit can furthermore ensure that only the minimal oscillation energy is used for a smooth behavior of the child / baby.Preferably, the drive system further comprises at least one sensor for determining a displacement of the distal end of the tension element, wherein the at least one sensor is preferably a contactless sensor.The mechanical sensor system installed in the prior art for measuring the oscillation speed and direction, for example via dynamos and servomotors, has a disadvantageous effect on the durability of the drive system, since these components can wear quickly. Furthermore, sustainability is adversely affected because the production of these components costs energy and, in particular, dynamos damp the oscillating movement and thus require more tractive force. In addition, mechanical components generate noise, in particular, surgical operating noise of servomotors.To measure the deflection of the oscillatory motion, a non-mechanical sensor may be used that can measure the displacement of the distal end of the tension member (i.e., a motion of the tension member). This can be an optical motion sensor which can selectively measure a rotation of a shaft of the drive unit and / or a speed of the tension element. Nevertheless, other sensors can also be used for the measurement, such as ultrasonic sensors or electromagnetic sensors (e.g. Hall sensors). The sensors can measure the movement of the traction element directly on the traction element itself, on the shaft of the drive unit, on the roller or on an additional component, such as a pole wheel, which rotates together with the shaft.Thus, the drive unit may be an actuator controlled by the control unit based on control logic. For this purpose, the control unit can receive sensor data (i.e. measured values) from the at least one sensor and process it further. As a result of the further processing, the control unit can issue control commands with which the drive unit can be controlled. A standardized single-board computer, preferably Raspberry Pi, can be used as the control unit, which can control the drive unit and can record and process the sensor data. However, other controls may be used as the control unit.According to one aspect of the present invention, when starting the drive system, the tensile force of the drive unit must use more energy in order to set the oscillating element in oscillation than is necessary for maintaining an oscillating movement of the oscillating element, since the complete weight of the oscillating element must be moved counter to the force of gravity. The problem, however, is that an excessively strong tensile force with a low weight of the oscillation element can lead to a jerklike unintentionally strong acceleration or to an undesired exceeding of the permissible oscillation amplitude. Therefore, the control unit can be configured to control the control of the drive unit at very short time intervals (a few milliseconds) in order to influence a movement of the traction element. In parallel thereto, the displacement of the distal end of the tension element can be measured via the at least one sensor and the control of the drive unit can be adapted based on these measurement data. Accordingly, the traction force of the drive unit can be actively controlled. Furthermore, it is possible to start first with a small tractive force (for example 10% of the maximum tractive force or the maximum power of the drive unit). The drive unit can have a power of 2 W to 10 W. The drive unit can be operated with 12 V DC current. Thus, efficient operation of the drive unit can be ensured. In the case of use as a drive for a spring cradle for children, the power of the drive unit is preferably between 3 W and 5 W. As has been shown to be particularly efficient, a power of 3.8 W (i.e. 0.6 A for 12 V DC). The tensile force can then be increased until a deflection is measured via the at least one sensor. With each oscillation movement (for example with half a period duration), the ratio of the actual and desired oscillation amplitude can be checked and the control of the drive unit by the control unit can be adapted in such a way that the desired oscillation amplitude is achieved. The closer the oscillation amplitude reaches the desired target value of the oscillation amplitude (i.e. oscillation intensity) that can be adjusted via a controller, the less tractive force is applied by the drive unit in order to achieve the desired oscillation amplitude as smoothly as possible. For this purpose, the desired minimum number of oscillation amplitudes until the desired oscillation intensity is reached can be stored in a memory of the control unit as configuration parameter. Thus, the control unit can control the drive unit so that the desired vibration amplitude is reached very smoothly or so that the desired vibration amplitude is reached quickly. Thus, the drive unit is adaptable to any requirements and individually controllable by the control unit.Thus, the control unit may be configured to cause actions (i.e. to control the drive unit) and to check a result thereof (i.e. the vibration that has occurred) whether it corresponds to the expected result. In the case of deviations, conclusions can be determined, for example, by an artificial intelligence or a rule-based system, which can be selectively displayed to the user and / or can lead to an adapted control by the control unit. Damage to the drive system and / or external disturbing factors can thus be detected at an early stage and communicated to the user (for example, a defect on the tension element, a foreign body in the oscillation region, a resistance during compression, etc.).By controlling the control unit, the drive system can have a so-called "cool-down" functionality, which dampens the oscillation movement when switched off by opposite acceleration of the amplitude and prevents a ringing using the force of the drive unit. For this purpose, it can be specified how many oscillating movements are to be carried out in order to stop the oscillating movement.Furthermore, the drive system can be controlled by the control unit according to a standby functionality, in which the drive unit is controlled in such a way that the distance between the oscillating element and the drive system remains as constant as possible, in order to simplify the loading and unloading of a person into the oscillating element. In this case, a movement of the tension element can be detected and the drive unit can be controlled in such a way as to generate a tension force in the opposite direction.In addition, the control unit can have an emergency stop functionality, which can be triggered by a dedicated switch, an operating element and all control elements connected via the Internet, such as voice assistance, app, etc. This emergency stop function uses the maximum available force of the drive unit in order to stop the oscillating movement as quickly as possible. Thus, in an emergency situation, operation of the drive unit can be ended as quickly as possible.Preferably, the drive system may comprise a force sensor configured to sense the force applied to the tension member.The force sensor may be a strain gauge, a piezo force transducer or the like. Thus, a force acting on the tension member can be measured. By changing, the control unit can infer different states of the oscillating element. Thus, an abrupt increase in the force acting on the tension element can speak to a sticking or an undesired external intervention in the oscillating movement of the oscillation element. Further, in the case of a sudden decrease in the pulling force, it can be determined that a person has been removed from the swing member or has fallen out. In addition, it can be determined by means of the force sensor whether the tension element hangs down or is connected to the oscillation element with tension. This is the case when the prestressing force applied by the drive unit can be measured with the force sensor. Then, the control unit may determine that the tension member is connected with tension to the swing member.Preferably, the control unit is configured to control the drive unit based on the force detected by the force sensor.Based on the information obtained by the force sensor, the control unit may react. For example, in the event of an abrupt increase in the tensile force in the tension element, it can stop the operation of the drive unit in order to avoid possible damage. In addition, an indication can be output to an interface or output device. Likewise, in the event of an abrupt drop in the tensile stress in the tension element, the control unit can stop the operation of the drive unit and / or issue an alarm. Furthermore, the information about the force acting in the tension element can be used to check whether the tension element is tensioned or slack. As soon as the control unit recognizes that the prestress is present in the tension element, it can assume that the tension element is under tension and therefore does not sag.Preferably, the biasing force is less than 15% of the maximum power of the drive unit, preferably less than 10% of the maximum power of the drive unit, and more preferably less than 8% of the maximum power of the drive unit.The prestressing force can be greater than the force resulting from the dead weight of the tension element. As soon as the prestressing force is greater, the tension element can be tensioned. In this case, a force resulting from the dead weight of the oscillating element and any person absorbed therein does not have to be exceeded, since the prestressing force is merely intended to tension the tension element and is not intended to move the oscillating element. The maximum output of the drive unit can result from the intended purpose of use of the drive unit. If relatively heavy objects and / or persons are to be caused to oscillate, the drive unit can have more power. At the same time, however, the tension element must also be designed to be correspondingly stable in order to be able to carry a relatively heavy load. It has been found that with a prestress which is less than 15% of the maximum power of the drive unit, the tension element can be prestressed reliably, with the result that sagging of the tension element can be avoided. This is also the case in which the tension element extends at least partially at an angle to the vertical. A value less than 10% of the maximum power is particularly advantageous when the tension member extends in the vertical, since then less force is required to place the tension member under tension (i.e. to pull it smoothly). The range of less than 8% offers particular advantages when using the drive unit in spring cradles for children or infants, since operation of the spring cradle is thus possible in a particularly efficient and quiet manner. In addition, this prestress is sufficient in the case of a tension element which is often designed to be delicate here.Preferably, the control unit is further configured to control the drive unit such that the oscillating element performs a predetermined oscillating movement.By means of a microcontroller-based control of the control unit, more complex vibration patterns than merely a uniform, permanent vibration movement are possible. For example, a vibration pattern similar to that in car travel can be simulated. A ringing can be prevented by the stop function, which dampens the swinging movement until standstill and suppresses a ringing by manual interventions. The achievement of the desired oscillation intensity can be achieved algorithmically by varying the force effect in a desired duration (i.e. possibly rapidly) and then be kept at a level. The control unit can detect a varying load in the oscillating element (for example by the above force sensor and / or by measuring an amplitude of the oscillating element) and drive unit accordingly, so that the applied force is matched to the payload (i.e. to the weight of the oscillating element and any persons received therein). The control unit can likewise identify operation outside of a permissible oscillation range and then execute a warning and / or an emergency stop.The control unit can measure the oscillation deflection. If the oscillation deflection is plotted on a Y axis and the time is plotted on an X axis, a harmonic oscillation movement can be mapped in a curve on the basis of a sine curve. In this case, the oscillation speed can be highest approximately when crossing the equilibrium point (that is to say the rest point of the oscillation-free state) and become lower the closer it comes to the minimum or maximum deflection (that is to say the reversal point). The control unit can use the knowledge about the vibration profiles in order to activate the above-described simulation of the tension element just before the reversal point is reached, so that the tension element remains constantly connected to the vibration element under tension over the entire duration of the vibration movement.Further, the control unit may measure a deviation from the expected vibration displacement to adjust or disable control of the drive unit. For example, the control unit can determine if the oscillation profile deviates from the sine curve profile, for example if no measured values are detected at the upper reversal point. Furthermore, the control unit may be configured to measure a deviation of the actual oscillating movement from predetermined complex oscillating patterns (e.g. simulation of a car trip) and to adapt the control of the drive unit according to the complex oscillating pattern. In this case, the set force relative to a spring used (as an example of a resilient member) and the weight of the swing member are too large, and the spring reaches a state where it cannot further deflect. This undesirable event can be detected by the control unit and corrected by automatic reduction of the maximum force exerted by the drive unit.A user can also control the intensity of the oscillating movement via an interface. The user can vary the intensity via a controller (plus / minus rocker switch, potentiometer, control via a mobile app or an electronic control panel). The control unit can recognize whether a lower limit or upper limit is reached and prevent operation outside these ranges due to the swinging motion in relation to the applied force. The lower limit of an oscillatory movement is given when no harmonic oscillation is possible any longer, since the movement would optionally be so small that it would no longer be perceived as oscillation or the detection accuracy of the control unit and / or of the sensors is undershot, so that they can no longer measure an oscillatory movement. The upper limit is reached when no upper reversal point can be measured as described above. In this case, the force applied by the drive unit can be reduced by the control unit to such an extent that the upper limit reaches a harmonic oscillation movement.In a preferred embodiment, the control of the oscillating movement can be effected via slide or rotary controls and rocker switches (+,-) on the drive system or can be controlled by corresponding visualizations on the surface of a touch screen or an app. According to an aspect of the present invention, the user may set the vibration intensity at an interval of the minimum and maximum vibration intensities. Thus, the user can set the predetermined swing motion. If the user sets the controller to an arbitrary value, a small force is first applied and measured, which effect the force has on the vibration. The force is increased at fixed time intervals (for example, in 0.5 s steps) until the control unit can determine a condition. The control unit can then determine a weight of the oscillating element and / or characteristic values of a spring. Successively, the force control is adapted until the oscillation amplitude has reached the set value. Initially, the force increases until the oscillating element sets itself in motion and the closer the oscillation reaches the set intensity, the lower the force becomes until it only contributes to the maintenance of the oscillating motion when the set oscillation intensity is reached.The control unit can also automatically control the intensity. Thus, a minimum oscillatory movement can be effected initially in order to require the least possible energy consumption. As soon as the control unit records information, for example, via further sensors (such as a vibration sensor or a microphone), oscillation intensity can be increased or vice versa reduced. Thus, for example, when using the drive system for a spring cradle for children, it is possible to react to an irregular behavior of the child and automatically adjust the operation of the drive unit. The assumption observed in practice is that children sleep more easily at a higher oscillation amplitude.In addition to a harmonic oscillation movement, the control unit can realize any other movement patterns (e.g. oscillation patterns) which can be mapped by up and down movements by controlling the drive unit. An upward movement is limited in that the load of the oscillating element cannot be further pulled against the force of gravity by a maximum tensile force of the drive unit or an elastic element, if provided, is fully compressed or compressed. The downward movements reported are determined by the maximum deflection of the spring resulting from the installed safety rope of a spring or by the maximum length of the tension element. The maximum upward acceleration is determined by the maximum tractive force of the drive unit, the maximum downward acceleration by the force of gravity. The maximum damping of a downward movement is determined by the maximum tensile force of the drive unit. Due to this property in conjunction with a very rapid actuation capability of the drive unit, a plurality of different movement patterns can be executed. Further output means can also be provided on the drive system, such as loudspeakers or lamps. The output means can likewise be controlled by the control unit in order to be able to simulate situations in a realistic manner together with the movement patterns.For example, a car trip can thus be simulated. In addition to the control unit storing a corresponding control of the drive unit, the drive system can communicate via an interface with an app that enables the user to record a car trip. This takes into account the empirical values that children respond differently to different driving profiles. For this purpose, the app can record vehicle noises, vibrations and brightness profiles (which arise, for example, as a result of lamp operations passing by). The user can select parts of the recording, if applicable, screen out measurement data such as brightness and transmit it to the drive system. This can play this profile by the control unit controlling the drive unit and / or the output means accordingly in order to simulate vibrations, noises and / or light profiles (e.g. changing light from passing lamp).The control of the drive unit, i.e. all actions (on, off, fast, slow,... ), the playing of movement patterns, can take place via any desired connected or connected interfaces (interaction mechanisms), such as a touch display, a mobile app or the integration with voice assistants (e.g. Alexa or Siri). These interaction mechanisms can also be used for communication of feedback, information and notifications.The drive system is preferably controlled via a mobile app that communicates with the drive system by means of Bluetooth or WLAN. According to one aspect of the invention, a simple coupling by Bluetooth is provided, in which the coupling mode of the drive system can be activated by pressing one or more control elements on the drive unit or a touch display. In a preferred embodiment, a touch display for controlling the drive system is removable from the drive system so that it can be arranged in an ergonomic position. It can be connected to the drive system via cable or radio.Preferably, the drive system comprises at least one resilient element which connects the drive system to the oscillating element.The resilient element may be a spring or other element capable of elastically deforming. In other words, the elastic element can deform upon application of a load and move back into the initial position again after removal of the load.Elastic elements (e.g. springs) can be characterized, for example, by their spring constant. Furthermore, the resilient element can be defined by a prestressing force and / or a number of the installed springs. In a preferred embodiment, different springs having a biasing force of 5N per spring and different spring constants may be used. The spring constants result in the resulting spring travel in conjunction with the loading force. The spring constants result from the loading force and the spring travel resulting therefrom.The drive system can be operated with different elastic elements. The springs can be used by cumulation or substitution between drive system and oscillating element. Different springs can be assigned, for example, different weights which are to be accommodated in the oscillating element (for example base spring 3-5 kg, each further additional spring +1 kg). The control unit can recognize which springs are used on the basis of the tractive force applied in conjunction with the amplitude deflection and oscillation frequency. Further, the control unit may determine whether the springs used match the payload. In this case, an individual determination of an optimum oscillatory movement together with the tolerance range can be stored in the control unit. If a deviation occurs, depending on the degree of the deviation, an indication to the user (looking LED, notification in a mobile app (especially occurs. Push notification), Alexa notification, etc.) and, if appropriate, additionally the denying of operation.The user may add additional accessories (such as additional springs) as well as additional functions. For this purpose, the user can couple his drive unit to his profile, which can be stored on the Internet offer of an operator.The control unit is preferably configured to automatically record properties of the resilient element and to control the drive unit on the basis thereof.In the preferred embodiment, the resilient element may be varied for various loads that may occur on the oscillating element. The control unit can be designed to recognize different resilient elements and to determine their parameters. These parameters, in particular the spring constants, can then be stored by the control unit as configuration parameters and taken into account in the control of the drive unit. Thus, different resilient elements may be used without the need to manually input parameters of the new resilient elements into the drive system. Rather, the drive system (in particular the control unit) can automatically identify a resilient element and its parameters and adapt the operation accordingly automatically. Thus, the use of the driving system can be simplified.As parameters of the resilient element (for example a spring), the spring constant (spring hardness) or the spring characteristic curve can be used. These describe the relationship between deformation (path s or angle φ) and force F or torque Mt. The spring characteristic curve, like its underlying Hooke's law, is usually linear to a good approximation and can in this case be characterized by means of a spring constant (as its gradient). According to one aspect of the invention, a resilient element having a non-linear characteristic may be used. It has been found here that, in particular when using the drive system for driving a baby spring cradle, a non-linear characteristic curve leads to an oscillation pattern which quickly leads to a calming of the child accommodated in the oscillation element.Preferably, the drive system comprises a recuperation device which is designed to recover energy from the oscillating movement of the oscillating element.Preferably, the drive system can comprise a drive unit with a guided track for the tension element, a guide for the tension element and a mechanical lock as well as the recuperation device. The recuperation device can be an electric machine which is driven by the traction element when the oscillating element moves away from the drive system. In other words, the recuperation device can be driven when the oscillating element is moved by the gravity force. Thus, in this case, an elastic vibrating element can be dispensed with. As a result, the drive system can be realized more compactly, since no resilient element has to be connected to the drive system and the oscillating element.According to another aspect of the present invention, there is provided a spring cradle system comprising:one of the above drive systems which can be arranged in a fixed position, anda vibration element for receiving at least one person, wherein the vibration element is fastened or can be fastened to the tension element.The swinging element may comprise a support and a suspension element, wherein the support may be a cloth or a dimensionally stable couch, which is suspended or suspendable on the suspension element. At least one person (e.g. a child or baby) can be accommodated in the wearer. The spring cradle system may be equipped with an inclination sensor. Preferably, the inclination sensor is arranged on the oscillating element or the tension element. Thus, the control unit can acquire information on the position of the swing member and control the drive unit based on this information. Furthermore, as the spring cradle system, it may comprise a deflection roller which is mounted on a frame on which at least the oscillating element is suspended. The tension element can be guided over the deflection roller and connected to the drive unit and to the oscillating unit, so that a force vector of the tension element is oriented at an inclination to the vertical. Preferably, the force vector transmitted from the tension element to the oscillation unit is inclined at an angle of approximately 45°. Thus, swing oscillation can be initiated advantageously. The drive system may be fixable at a fixed point (e.g., a door frame or a frame). For this purpose, the spring cradle system can have a fastening mechanism. The oscillating element can be connected below the drive system to the traction element and optionally to the drive system by a resilient element. Since the payload-carrying drive unit is always located on an axis with the resilient element and thus the payload, the inclination sensor supplies input data in order to achieve a harmonic rocking movement by a corresponding force actuation. Analogously to the above, the control unit can also execute a cool-down, stand-by and emergency-stop function during the rocking movement.The spring cradle system can be used as a baby spring cradle system. Furthermore, the spring cradle system can also be used by adult humans.The spring cradle system preferably comprises at least one sensor which is configured to detect a state of the at least one person recorded in the oscillating element, wherein the control unit is configured to control the drive unit on the basis of the detected state and / or to output the state of the at least one person to an output unit.The sensor can comprise, for example, a thermal imaging camera which recognizes that the person recorded in the oscillating element is too cold or too warm and informs a user. Furthermore, the sensor can comprise a vibration sensor and / or a microphone, so that an activity of the person can be recorded. The control unit can control and adapt the operation of the drive unit on the basis of this sensor data. Furthermore, the control unit can record and store different reactions of the person to different oscillation patterns and thus generate experience values in which oscillation patterns which reactions of the person occur most frequently. For example, in the case of infants, the control unit can determine which oscillation pattern leads to a settling or to a sleep of the baby. Furthermore, the control unit can determine an average sleep duration of the person using empirical values and / or the sensor data and display it to a user. The user can be informed about states and / or events to be expected by push notification or Alexa notification, so that the user can be timely with the spring cradle system, for example before a baby wakes up. Further, the sensor may comprise a moisture sensor, for example, detecting that a baby has full the diapers. This information can also be passed on to a user, for example via a display on the spring cradle system and / or via an interface, in particular wirelessly, to a mobile device.In particular, in order to be able to make the above determinations, the control unit can comprise an artificial intelligence which can monitor all sensor data in order to obtain findings on the state or behavior of the person recorded in the vibration element and to cause actions. The artificial intelligence can be, for example, an artificial neural network which can be trained by using the information about the oscillating movement of the oscillating element as input data and using the reactions of the person recorded in the oscillating element as output data. The neural network can be trained customized for each user by continuously retraining or untraining it when using the spring cradle system. Thus, one control of the spring cradle system can be individually adjusted.Thus, the control unit can determine the optimum parameters for automated operation by means of rule-based technology or artificial intelligence, taking into account the boundary conditions that occur, and control the control unit accordingly.Moreover, the controller may anonymously send sensor data to a central Internet service to query empirical values from installations of other spring cradle systems to similar sensor data, so as to speed up the own learning (through more available training data).According to a further aspect of the present invention, there is provided a method for simulating an elastic tension member, comprising the steps of: a) providing a drive system comprising a tension member having a distal end configured to be attached to a swing member and a drive unit configured to increase and / or decrease a free length of the tension member to change a position of the swing member relative to the drive system, b) operating the drive unit such that a bias is applied to the tension member to simulate an elastic tension member, c) determining that the distal end of the tension member does not move towards the drive unit, and d) terminating the simulation of the elastic tension member.A mechanical tension element can thus be dispensed with, since such a tension element can be simulated by the method according to the invention by targeted actuation of the drive unit. Thus, the same advantages can be achieved by the method as by the above device and a particularly quiet and efficient operation of a spring cradle can be achieved.Preferably, the method further comprises the following steps:e) operating the drive unit to initiate a swinging movement of the swinging element such that the distal end of the pulling element moves away from the drive unit,f) determining that the distal end of the tension member no longer moves away from the drive unit, andg) operating the drive unit so that the prestress is applied to the tension element in order to simulate an elastic tension element.All advantages of the method also apply analogously to the device and vice versa. Further, individual aspects of embodiments may be combined with other aspects of other embodiments and form novel embodiments.Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. This shows FIG. 1 is a schematic illustration of a propulsion system according to an embodiment of the present invention in use with a spring cradle system, FIG. 2 is a schematic illustration of a drive system according to another embodiment of the present invention in use with a spring cradle system, FIG. 3 is a schematic illustration of a drive system according to another embodiment of the present invention in use with a spring cradle system, FIG. 4 is a schematic illustration of a drive system according to another embodiment of the present invention in use with a spring cradle system, FIG. 5 is a schematic illustration of a drive system according to another embodiment of the present invention in use with a spring cradle system, FIG. 6 is a schematic illustration of a drive system according to another embodiment of the present invention in use with a spring cradle system, FIG. 7 is a schematic illustration of a drive system according to another embodiment of the present invention in use with a spring cradle system; and FIG. 8 is a schematic illustration of a spring cradle system according to an embodiment of the present invention.FIG. 1 is a schematic illustration of a spring cradle system 100. The spring cradle system comprises a drive system 2 according to a further embodiment of the present invention. In the present embodiment, the spring cradle system 100 can be hung in a fixed position with a fastening 1. For example, the spring cradle system 100 may be suspended from a hook on a ceiling, a door frame and / or a frame. The drive system 2 is connected to the fastening 1 in such a way that the drive system 2 hangs below the fastening 1 in the operating state. The spring cradle system 100 further comprises a tension element 4 and a resilient element 3. In another embodiment not shown, the resilient element is an elastic element comprising a stretchable material (such as rubber or elastomer) and which may vary elastically in length. The tension element and the elastic element 3 are both fastened to the drive system 2 so that in the operating state they hang below the drive system 2. A suspension element 5 is connected to the tension element 4 and the elastic element 3, serving as part of the oscillating element. On the suspension element 5 in turn a stretcher 6 is arranged (for example suspended) in which a person (for example a baby, child) can find room. Thus, the support 6 and the suspension element 5 together form the swinging element.The tension element 4 can be shortened by the one drive unit 21 (see FIG. 2 ) accommodated in the drive system 2 in such a way that a distance between the oscillating element and the drive system 2 decreases. In the present embodiment, the tension element is wound and unrolled on a roller 7 (not shown in FIG. 1 ) in order to vary the distance between drive system 2 and oscillating element. By subsequently releasing the tension element 4, the oscillating element can again move away from the drive system 2 due to the gravity force. In this case, the tension element 4 exerts no force on the oscillating element. The elastic element 3 deforms elastically and thereby decelerates the movement of the oscillating element until standstill. Subsequently, the elastic element 3 exerts a force on the oscillating element which is opposite to the previous movement, so that the oscillating element moves towards the drive system 2 again in a rearward movement. During the return movement, the tension element 4 exerts no force on the oscillating element. Thus, vibration of the vibration element can be initiated.In order to be able to maintain the oscillation by periodic tightening of the tension element 4, the tension element 4 must always be kept under tension. In other words, the tension element 4 should not slacken, so that a direct tightening of the oscillating element is possible by rolling up the tension element 4. In the prior art, a tensioned tension element is provided by a mechanical tension element. In this case, the mechanical clamping element is usually a helical spring on a shaft of the drive unit 21. Thus, a free length of the tension element 4 is shortened during an upward movement of the oscillating element (i.e. during a movement toward the drive system 2) such that the tension element is always tensioned between the drive system and the oscillating element. This ensures that, when the drive unit is operated, the movement of the oscillating element can be acted upon directly. Thus, complex vibration patterns can also be realized by targeted operation of the drive unit 21. Likewise, a harmonic oscillation which is maintained constant, for example, can also be provided.FIG. 2 is a schematic illustration of the spring cradle system 100 according to another embodiment of the present invention. In contrast to FIG. 1, a housing 9 of the drive system is cut away in FIG. 2, so that the elements shown in the drive system 2 are visible. For example, the roller 7 is shown, which can be driven in rotation by the drive unit 21 and around which the tension element 4 can be wound and unwound. In addition, in the present embodiment, a motion sensor 8 is arranged in the housing 9 of the drive system. The motion sensor 8 is configured to detect a movement of the tension element 4. In this case, the motion sensor 8 can detect a motion amount and a motion direction. Thus, a control unit 22, which is also arranged in the drive system, can infer the position of the oscillating element relative to the drive system 2. Consequently, the drive unit 21 can be controlled highly accurately in order, on the one hand, to realize a predetermined oscillation pattern and, on the other hand, to keep the tension element 4 always under tension. In the present embodiment, the tension element 4 is guided through the sensor 8. The sensor can be provided with two measuring rollers, for example, between which the tension element is clamped. By rotating these measuring rollers, the sensor can conclude that the tension element 4 is moving.FIG. 3 is a schematic illustration of the spring cradle system 100 according to another embodiment of the present invention. The embodiment shown in FIG. 3 corresponds to the embodiment shown in FIG. 2, with the difference that the motion sensor 8 in the present embodiment is a non-mechanical sensor. In other words, the sensor 8 may be an optical or an electromagnetic sensor. Therefore, operation of the drive system 2 can be particularly quiet and low-locking. Here, the sensor 8 can be directed, for example, at a pole wheel 12 which is mounted on the shaft of the drive unit 21. The pole wheel 12 can have regular recesses which can be detected by the sensor 8. Furthermore, the pole wheel may have magnetized elements which can be detected by the sensor 8. In this case, the sensor 8 may be a Hall sensor.FIG. 4 is a schematic illustration of the spring cradle system 100 according to another embodiment of the present invention. Here, the present embodiment includes a vibration sensor 14 in addition to or as an alternative to the sensors of the above embodiments. A movement of the person in the stretcher 6 can thus be detected. In particular, due to the connection between the drive system 2 and the oscillating system being held in tension by the tension element 4, movements of the person in the stretcher 6 can be transmitted to the drive system 2. Then, the control unit 22 can tune the operation of the drive unit 21 to the detected vibrations. If, for example, the detection of vibrations by the vibration sensor 14 gives rise to an irregular behavior of a child accommodated in the stretcher 6, the oscillation intensity can be increased or, conversely, reduced. The assumption observed in practice is that children sleep more easily at a higher oscillation amplitude.FIG. 5 is a schematic illustration of the spring cradle system 100 according to another embodiment of the present invention. The present embodiment differs from the preceding embodiments in that no elastic element is provided here, but the oscillating element is connected to the drive system 2 merely by means of a tension element 4. Furthermore, the drive system 2 has a roller 15 with a guide 16 for the tension element 4. In other words, the tension element 4 is wound onto the roller 15 in a targeted manner by the guide 16. Thus, a constant force can always be applied from the roller 15 to the tension member 4 and vice versa. The roller 15 is driven by a drive unit (not shown in FIG. 5 ) as in the above embodiments. Further, a recuperation device 18 is provided in the drive system 2 and is connected to the shaft on which the roller 15 is arranged. Thus, upon movement of the oscillating element away from the drive system 2 (i.e. driven by the gravity force), energy can recover from the movement of the oscillating system. Furthermore, a motion sensor 8 in the form of a dynamo is connected to the shaft. Thus, the position of the oscillating element relative to the drive system can be reliably determined. In addition, this embodiment has a mechanical locking element 17 which is designed to hold the tension element 4 if, for example, no movement of the oscillation element is desired.FIG. 6 is a schematic illustration of the spring cradle system 100 according to another embodiment of the present invention. This embodiment corresponds to the embodiments shown in FIGS. 2 to 4, with the difference that the motion sensor is directed directly onto the tension element 4 and can register a movement of the tension element 4. The sensor is an ultrasonic sensor. This non-mechanical sensor, like the above-mentioned optical sensors, has the advantage that operation of the drive system 2 is very quiet and low in wear.FIG. 7 is a schematic illustration of the spring cradle system 100 according to another embodiment of the present invention. This embodiment corresponds to the embodiments shown in Figures 2 to 4 and 6, with the difference that the motion sensor is designed as a dynamo which is located on the same shaft as the roller 7 and the drive unit 21. Consequently, movements of the roller 7 and thus of the tension element can be easily detected.FIG. 8 is a schematic illustration of a spring cradle system according to an embodiment of the present invention. In this case, the tension element 4 is deflected by means of second deflection rollers, so that the tension element 4 runs at an angle of approximately 45° relative to the horizontal from the drive system 2 to the suspension element 5. Further, the stretcher 6 of the present embodiment has an inclination sensor. Thus, the control unit 22 can acquire information on the position of the support 6 and control the drive unit 21 based on this information. The deflecting rollers are mounted on a frame on which at least the oscillating element is suspended. Thus, by actuating the tension element 4, a swinging movement can be initiated.List of reference characters1 Fastening 2 Drive system 3 Resilient element 4 Tension element 5 Suspension element 6 Support 7 Roller 8 Motion sensor 9 Housing 12 Pole wheel 14 Vibration sensor 15 Roller with guided track 16 Guide for tension element 17 Mechanical lock 18 Recuperation device 21 Drive unit 22 Control unit 100 Spring cradle system

Claims

Drive system (2) for a spring cradle system (100), in particular for a baby or baby spring cradle, for generating a swinging movement, comprising: a tension element (4) with a distal end configured to be attached to a swinging element, a drive unit (21) configured to increase and decrease a free length of the tension element (4) in order to change a position of the swinging element relative to the drive system (2), and a control unit (22) configured to control the drive unit (21) such that a biasing force acts on the tension element (4) independently of the position of the swinging element relative to the drive system (2), wherein the control unit (22) is configured to drive the drive unit (21) such that a mechanical tension element is simulated, and wherein the drive system (2) comprises at least one resilient element (3), connecting the drive system (2) to the oscillating element.Drive system (2) according to claim 1, further comprising at least one sensor (8) for determining a displacement of the distal end of the traction element (4), wherein the at least one sensor (8) is preferably a contactless sensor.The drive system (2) according to any one of the preceding claims, wherein the drive system (2) comprises a force sensor configured to sense the force applied to the traction element.The drive system (2) according to claim 3, wherein the control unit (22) is configured to control the drive unit (21) based on the force detected by the force sensor.Drive system (2) according to any of the preceding claims, wherein the biasing force is less than 15% of the maximum power of the drive unit (21), preferably less than 10% of the maximum power of the drive unit (21) and more preferably less than 8% of the maximum power of the drive unit (21).The drive system (2) according to any one of the preceding claims, wherein the control unit (22) is further configured to control the drive unit (21) such that the oscillating element performs a predetermined oscillating movement.Drive system (2) according to claim 6, wherein the control unit (22) is configured to detect characteristics of the resilient element (3) and to control the drive unit (21) based thereon.The drive system (2) according to any of the preceding claims, wherein the drive system (21) comprises a recuperation device (18) configured to recover energy from the oscillating movement of the oscillating element.Spring cradle system (100) comprising: a drive system (2) according to one of the preceding claims, which can be arranged in a fixed position, and a vibration element for receiving at least one person, wherein the vibration element is fastened or can be fastened to the tension element (2).The spring cradle system (100) according to claim 9, further comprising at least one sensor (14) configured to detect a state of the at least one person accommodated in the swinging element, wherein the control unit (22) is configured to control the drive unit (21) based on the detected state and / or to output the state of the at least one person to an output unit.A method for simulating an elastic tension element, comprising the following steps: a) providing a drive system (2) comprising a tension element (4) having a distal end configured to be attached to a swing element and a drive unit (21) configured to increase and / or decrease a free length of the tension element (4) to change a position of the swing element relative to the drive system (2), wherein the drive system (2) comprises at least one resilient element (3) connecting the drive system (2) to the swing element, b) operating the drive unit (2) such that a bias is applied to the tension element (4) to simulate an elastic tension element, c) determining that the distal end of the tension element (4) does not move towards the drive unit (2), and d) ending the simulation of the elastic tension member.The method according to claim 11, wherein the method further comprises the steps of: e) operating the drive unit (2) to initiate a swinging movement of the swinging element such that the distal end of the pulling element (4) moves away from the drive unit (2), f) determining that the distal end of the pulling element (4) no longer moves away from the drive unit (2), and g) operating the drive unit (21) such that the bias is applied to the pulling element (4) to simulate an elastic tensioning element.

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