EP3383781B1 - Method for controlling a braking device of an elevator system - Google Patents

Description

The invention relates to a method for controlling a braking device of an elevator system, an elevator system with means for executing the method and a computer program for implementing the method.

Here, a basically known braking device of an elevator system is activated. The braking device includes, for example, an electromagnetically ventilated spring pressure brake and an electronically controllable electromagnet for releasing the spring pressure brake. The braking effect is achieved by means of the spring force of at least one spring. At least in the de-energized state of the electromagnet, due to the spring force, a pressure element of the spring pressure brake having a brake lining rests on a counter surface, for example on a brake disk of the elevator drive. The pressure element can be a pressure plate that can be pressed onto the brake disc or it can be a pressure or brake shoe that can be pressed onto a brake drum, for example. The braking effect can be canceled by activating the electromagnet by lifting the pressure element against the force of the spring from the counter surface by means of the electromagnet.

Such or a comparable braking device of an elevator system is intended to hold an elevator car of the elevator system in a stopping position. In the case of an elevator system comprising several elevator cars, this has a separate braking device for each elevator car. The following description is continued in the interest of better readability, but without foregoing further general validity, using the example of an elevator installation with exactly one elevator car that can be moved in exactly one elevator shaft. An elevator system with several elevator cars in one shaft or in several shafts must always be read.

In addition to holding the elevator car in a holding position, a braking device is necessary and designed to be able to brake the elevator car safely at any time during operation, that is to say especially in the event of a fault. Possible error situations are, for example, an unexpected opening of a cabin door, a driving speed that is too high, a loss of a stopping position and so on.

When the braking device is activated, it is often provided that the activation takes place in such a way that a maximum braking effect results. This leads to a strong and uncomfortable delay for passengers in the elevator car. To avoid this, systems are known which regulate or control an effective braking torque in each case.

From the JP 2004/131207 A A braking device is known in which a plurality of electromagnets are controlled by means of a pulse-width-modulated control signal.

From the GB 2 153 465 A a load and driving direction-dependent control of a braking device is known. The EP 1 870 369 A includes explanations for determining mass parameters of an elevator system.

An object of the invention is to provide a braking device of the type mentioned at the outset which, over a long period of operation of the elevator system and the braking device comprised by it, brings about an efficient metering of a braking torque applied in each case, such that on the one hand a necessary deceleration of the elevator car is achieved and on the other hand, passengers in the elevator car do not perceive the forces acting on the deceleration as disturbing.

This object is achieved by means of a method for controlling a braking device, in particular a braking device of the type mentioned at the outset, with the features of claim 1. The braking device comprises at least one pressure element with a brake lining, which is automatically detachable from a counter surface and is intended to effect the intended braking effect, in particular at least one electromagnetically releasable spring pressure brake with such a pressure element. Furthermore, the braking device comprises means for automatically releasing the or each pressure element from the counter surface, for example at least one electronically controllable electromagnet.

The following is provided as part of the method for actuating the braking device: by means of a model of the elevator system, taking into account a respective operating state of the elevator system, such as a respective direction of travel of an elevator car of the elevator system to be braked, an automatically determined respective state of charge of the elevator car and a predetermined or predefinable intended car deceleration a braking torque required to brake the elevator car is determined.

For this purpose, the model of the elevator system includes a mass of the moving parts of the elevator reduced to the location of the braking device, such as the elevator car, permissible payload, counterweight, inertial masses of idling rollers and drives, rope masses taking into account the factors of transfer, gear ratios and roller and drive diameters. In addition, the model of the elevator system contains an experience based on friction that counteracts movement of the elevator parts. Using these model sizes and the ones already noted above The braking torque required to brake the elevator car can be determined in accordance with variable sizes corresponding to the respective operating state of the elevator system.

In one version, the model of the elevator system is described in sufficient detail simply by specifying a weight ratio of the permissible payload to the car weight and a degree of balancing. The degree of balancing determines the proportion of the load in the elevator car that is necessary to achieve a mass balance between the counterweight side and the car side. A degree of balancing of 50% determines, for example, that the mass balance is established when the elevator car is loaded with half the permissible load. Thus, as a rule, the braking torque required to brake the elevator car can be determined solely using these few parameters and the respective operating state of the elevator system - direction of travel and current state of charge of the elevator car to be braked. The necessary braking torque is not to be understood as an absolute value, but the required braking torque can be a braking relation. Depending on the size, total mass, transfer factors and type of elevator, an appropriately dimensioned braking device with a corresponding possible braking torque is required. The braking relation then essentially gives a braking torque factor which is referred to as braking torque in the present context.

On the basis of the braking torque or the corresponding braking relation determined in this way, a control signal for controlling a device functioning as a means for automatically releasing the or each pressure element from the counter surface, that is to say, for example, a control signal for controlling the or each electromagnet, is generated and fed to the respective device, so that the elevator car is braked. A dependency of the braking torque and the control signal on one another is stored in a braking characteristic of the braking device. This means that if the braking torque is required, the required control signal can be read from the braking characteristic. The automatically releasable pressure element or also a plurality of such pressure elements is briefly referred to below as the brake together with the counter surface in accordance with customary usage. If the device for releasing the brake is not activated at all, the maximum braking effect results. If the device for releasing the brake is actuated to a maximum, the brake is completely released and there is no braking effect at all. Controlling the device for releasing the brake between these extremes allows the braking action to be metered. The control signal generated on the basis of the determined braking torque basically effects the metering of the braking effect in accordance with the determined braking torque.

To ensure as good a match as possible of the resulting braking effect with the previously empirically determined necessary braking torque, that is to say the braking characteristic an actual car deceleration is determined when the elevator system is braked. On the basis of the determined actual cabin deceleration, the braking characteristic of the braking device is calibrated, namely a calibration of the determined necessary braking torque and / or a calibration of the control signal generated on the basis of the determined necessary braking torque.

The control signal used to control the device for releasing the brake or a corresponding control variable for controlling the electromagnetically ventilated spring pressure brake is in a physically defined connection to the resulting pressing force of the pressure element on the counter surface and thus taking into account a corresponding brake friction coefficient for the braking torque. This physically defined relationship determines the course of the braking action between the extremes, which makes it possible to dose the braking action. This physically defined relationship is the basis of the braking characteristic. The braking device or the braking characteristic of the braking device is calibrated on the basis of the determined actual car deceleration in a specific operating state of the elevator system. The physically defined relationship or braking characteristic is therefore recalibrated on the basis of the actual cabin deceleration. If the actual cabin deceleration corresponds exactly to the desired cabin deceleration, the braking characteristic does not change.

In one embodiment, the braking characteristic represents the braking torque to be expected as a function of the control signal. The braking torque to be expected of an electromagnetically ventilated spring pressure brake results from a spring force value and a magnetic force value. The spring force value includes the spring force caused by a spring and the magnetic force value takes into account the counterforce caused by the electromagnet. The counterforce caused by the electromagnet is typically a quadratic dependence on a coil current of the electromagnet and the control signal generally determines the coil current directly. In the spring force value and in the magnetic force value, respective friction values, lever systems and possibly other influencing factors, such as an air gap or a summation of several braking surfaces, are taken into account.

The calibration of the braking device or the braking characteristic of the braking device thus includes a correction of the spring force value and the magnetic force value. The braking characteristic recalibrated by means of the corrected spring force value and the corrected magnetic force value thus reflects an actual braking behavior.

The advantage of the approach proposed here is that a predetermined or predefinable desired cabin deceleration is incorporated into the method for controlling the braking device. The desired cabin delay is chosen so that on the one hand a necessary delay the elevator car results and, on the other hand, passengers in the elevator car do not perceive the forces acting on the deceleration as disruptive. Compliance with these two boundary conditions is briefly referred to below as efficient metering of the braking torque. Furthermore, the advantage of the approach proposed here is that such an efficient metering of a braking torque applied in each case is possible during a long period of operation of the respective elevator system, theoretically during the entire operating time of the elevator system. By determining an actual cabin deceleration and recalibrating the braking characteristics on the basis of the actual cabin deceleration, transient effects in the overall system of the elevator system or in the braking device, such as temperature or air humidity differences and the associated influences on the braking process and material wear in the elevator system and related things Consider changing resistance to movement and the like, so that regardless of such effects, a constant braking effect is achieved even over a long period of operation.

Such a calibration is carried out in such a way that, for example, in the case of an actual cabin delay that is only half as large as the desired cabin deceleration, a calibration is carried out which, in the next braking operation, leads to a doubling of the determined necessary braking torque or a corresponding adjustment of the control signal, for example an adjustment of a pulse width modulated control signal. The continuous calibration during the operation of the elevator system brings about the constant braking effect even over a long operating period, that is to say at least for a period of several months or at least during a normal service interval. Due to the efficient metering of the braking torque applied in each case, the elevator system as a whole, the passengers traveling along and also the braking device and the materials which come into contact to maintain the braking effect are protected.

Advantageous embodiments of the approach presented here are the subject of the dependent claims. References used here indicate the further development of the subject matter of the main claim through the features of the respective subclaim; they are not to be understood as a waiver of the achievement of independent, objective protection for the combinations of features of the related subclaims. Furthermore, with regard to an interpretation of the claims in the case of a more specific specification of a feature in a subordinate claim, it can be assumed that there is no such restriction in the respective preceding claims.

In an advantageous embodiment of the method, the calibrated braking characteristic is evaluated in relation to tolerable limit characteristics. The calibrated braking characteristics are released for further use as long as the calibrated braking characteristics within the limits determined by the limit characteristics. The calibration is done automatically. The limit characteristics indirectly determine the extent to which deviations between the actual cabin delay and the desired cabin delay are considered to be comparatively small and generally tolerable deviations. By automatically calibrating in the event of such a small deviation, that is to say without intervention by operating or service personnel, the braking device is continuously and automatically adapted to any transient effects.

In a further, additional or alternative advantageous embodiment of the method, a warning message is issued as soon as the calibrated braking characteristic leaves the limits determined by the limit characteristics. This gives the operating or service personnel an indication of an existing or imminent exceptional situation and can take suitable countermeasures, e.g. check and, if necessary, replace the brake lining of the pressure element, check the counter surface and replace if necessary and / or check a spring or the like acting on the pressure element and replace if necessary. The warning message can be output in the form of an optical and / or acoustic warning message and / or an electronic message by automatically activating at least one corresponding actuator. The warning message can additionally or alternatively also be output in such a way that the elevator system is automatically switched to an assigned, predetermined or predefinable operating mode. In the operating mode, for example, the elevator car is only moved at a reduced speed. Alternatively, the automatically activated operating mode can also consist in that the elevator car can no longer be moved until it has been acknowledged by operating or service personnel.

In a further embodiment of the method, it is provided that a pulse-width-modulated control signal is generated as the control signal on the basis of the calibrated necessary braking torque. A pulse-width-modulated control signal has the advantage that when a pulse-width modulator is implemented in terms of circuitry, using electronic switching elements, in particular bipolar or MOS transistors or IGBTs, they can operate in a low-loss switching mode.

In a still further embodiment of the method, it is provided that a predetermined or predeterminable number of braking operations and a calibration are carried out during commissioning of the elevator system and / or for the one-time or regular adjustment of the braking device during an initialization phase of the braking device. Several braking processes enable a better calibration of the braking device in that with each new calibration during the initialization phase, the calibration that is carried out in each case always aligns the actual cabin deceleration better with the desired cabin deceleration brings. In an advantageous addition to this embodiment of the method, it is provided that at least one braking operation following an upward movement and at least one braking operation following a downward movement of the elevator car take place within the braking operations carried out during the initialization phase. An elevator fitter commissioned with the adjustment of the elevator system therefore no longer has to carry out corresponding adjustment work manually, but instead the brake device calibrates itself according to the method.

In a further embodiment of the method, it is provided that an expected braking time is calculated on the basis of the desired cabin deceleration and that after the expected braking time has elapsed, the control signal is specified such that the braking device generates a maximum braking torque. As a result, the elevator system is held safely and in an energy-saving manner. In the case of the brake device shown at the beginning, this means that the device for releasing the brake is not actuated at all, that is to say the actuation signal is set to zero. This results in the maximum braking effect. At the same time, this means that the electronically controlled electromagnet is switched off.

Overall, the innovation proposed here is also an elevator installation with at least one elevator car and a braking device intended to brake the elevator car, and means for carrying out the method as described here and below. The means for executing the method preferably include at least the model of the elevator installation and an elevator controller. The method can advantageously be implemented in the form of software or a combination of software and hardware. In this respect, the innovation is also a computer program functioning as a control program for the elevator installation, which includes program code means to carry out all the steps of the method described here and below if the control program is executed by means of an elevator control of the respective elevator installation. In an implementation of the method and, if appropriate, individual configurations of the same, the elevator control comprises a memory in which the control program is loaded, and a processing unit in the form of or in the manner of a microprocessor, by means of which the control program can be executed. When operating the elevator system and when operating the elevator control system, the method or the method is carried out in an optional embodiment by executing the control program.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawing. Corresponding objects or elements are provided with the same reference symbols in all figures. The exemplary embodiment is not to be understood as a limitation of the invention. Rather, there are numerous changes and changes within the scope of the present disclosure Modifications possible, in particular those variants, elements and combinations, for example by combining or modifying individual in conjunction with the features or elements or method steps described in the general or special description part and contained in the claims and / or the drawing for the person skilled in the art With regard to the solution of the task can be removed and lead to a new object or to new process steps or process step sequences through combinable features, also insofar as they relate to test and working processes.

Fig. 1

eine Aufzugsanlage mit einer Aufzugskabine und einer Bremseinrichtung zum Abbremsen der Aufzugskabine,

Fig. 2

eine mögliche Ausführungsform einer Bremseinrichtung,

Fig. 3

eine Darstellung zur Erläuterung einer Implementation des hier vorgeschlagenen Ansatzes zur Ansteuerung einer Bremseinrichtung,

Fig. 4

eine alternative Implementationsmöglichkeit, und

Fig. 5

eine graphische Darstellung eines Kalibriervorgangs.

Show it:

Fig. 1

an elevator installation with an elevator car and a braking device for braking the elevator car,

Fig. 2

a possible embodiment of a braking device,

Fig. 3

2 shows a representation to explain an implementation of the approach proposed here for controlling a braking device,

Fig. 4

an alternative implementation option, and

Fig. 5

a graphical representation of a calibration process.

The representation in Figure 1 schematically shows, in a very simplified manner, an elevator installation 10 of a type known per se with an elevator car 12, a supporting cable 14 for moving the elevator car 12 and a counterweight 16 at the end of the supporting cable 14 opposite the elevator car 12. The supporting cable 14 is guided over at least one pulley 18. The rope pulley 18 or at least one of the rope slides 18 is driven by means of an electric motor which acts as a drive 20. At least one braking device 22 is provided for braking the elevator car 12 during operation of the elevator system 10.

The specific type of braking device 22 is not essential to the invention. The approach proposed here can be used for any type of braking device 22 as long as it can be released automatically. When represented in Figure 1 the braking device 22 is shown schematically simplified in a form such as this from the GB 2 153 465 A is known. Accordingly, the braking device 22 comprises - as is shown in further detail in the enlarged illustration in FIG Figure 2 is shown - an automatically releasable pressure element 24 intended to effect a braking effect. The pressure element 24 is pressed to maintain the braking effect on a counter surface 26 which moves relative to the pressure element 24 when the elevator car 12 is moved. The counter surface 26 can be, for example, a peripheral surface or a side surface of a brake disc 28 driven by the drive 20 together with the driven rope pulley 18 or a surface of a guide rail (not shown) which functions as a braking track.

At the in Figure 2 In the configuration shown, the pressure element 24 bears against the peripheral surface of the brake disk 28 shown here, which acts as the counter surface 26, so that the braking device 22 develops the intended braking effect. The braking device 22 is passive. This means that the braking effect is always present without an external influence canceling the braking effect. This is with the in Figure 2 embodiment shown realized by means of a spring 30. The spring 30 is clamped between an abutment and the pressure element 24 and the pressure element 24 is accordingly on the counter surface 26 due to the spring force of the spring 30. At the in Figure 2 The embodiment shown functions as a means for automatically releasing the pressure element 24 and thus as a means for automatically canceling the braking action, an electromagnet 32. This comprises, in a manner known per se, a coil through which current flows when activated and a ferromagnetic core. A stamp, which carries the pressure element 24 at its end, functions as the ferromagnetic core.

The strength of a magnetic field resulting from a current flow through the coil determines the respectively acting force by means of which the pressure element 24 is lifted or pulled away from the counter surface 26 against the spring force of the spring 30. When the electromagnet 32 is actuated to a maximum, the braking effect disappears; on the other hand, the braking effect is at a maximum if the electromagnet 32 is not actuated at all. A control of the electromagnet 32, which functions as a device for releasing the brake, between these extremes accordingly allows the braking action to be metered, and the respective control thus determines the strength of the braking action of the braking device 22 and accordingly the braking torque applied by the braking device 22. Spring pressure brakes in the form of disc brakes are often used here. Here, the counter surface 26 is defined by a brake disk rotating with a drive of the elevator. The pressure element 24 is provided with a brake pad which can interact with the counter surface 26. The pressure element 24 is lifted or pulled away from the counter surface 26 by the electromagnet 32 against the spring force of the spring 30. A brake play between the brake pad of the pressure element 24 and the counter surface 26 when the electromagnet 32 attracts the pressure element 24 is minimal. The brake play is in the range from almost zero to a few tenths of a millimeter. This makes the influence of an air gap in the magnetic circuit negligible. In addition, an impact noise when the brake device is closed is minimized, since the brake pad is almost against the counter surface.

Based on the representation in Figure 3 In the following, the determination of a braking torque M required in each case and the generation of a control signal 40 for controlling the device for releasing the brake, in the exemplary embodiment shown the generation of a control signal 40 for controlling the electromagnet 32, are explained: The braking torque M required in each case is explained by means of a model 42 of the elevator system 10 determined. To determine the braking torque M, the model 42 takes into account a respective direction of travel R of the elevator car 12 and one Current state of charge m of the elevator car 12. The model 42 receives electronically processable values for these two parameters R, m from an elevator control 44 (the model 42 can also be implemented as a partial functionality of the elevator control 44). As a further default, model 42 processes an input value encoding a desired cabin delay Vs. This can also be transmitted to the model 42 by the elevator control 44. However, the parameter can also be entered as an external parameter and thus fed directly to the model 42. The desired car deceleration Vs is selected and set such that on the one hand there is a necessary deceleration of the elevator car 12 and on the other hand passengers in the elevator car 12 do not perceive the forces acting on the deceleration as disruptive.

The model 42 functions as a system model of the elevator installation 10 and includes a mathematical description of the dynamics of the elevator installation 10. The model 42 takes into account an elevator mass, a permissible cabin load, a degree of balancing, any translation factors, and optionally a system friction coefficient. The elevator mass comprises inertial masses of the drive 20, of deflection rollers 18 and of linearly moving masses such as ropes 14, counterweight 16 and car 12. The permissible car load corresponds to the permissible maximum load of the elevator car 12. The degree of balancing determines the proportion of the permissible load in the elevator car 12 in order to achieve a static equilibrium state of the elevator installation 10 (counterweight side and car side). The system coefficient of friction determines a resistance which counteracts movement of the elevator car 12 as a result of friction. This plant-specific data can be determined in different ways. For example, they can be predetermined at the factory. Alternatively, they can also be learned in the elevator system, for example in a way like this in the EP 1 870 369 A1 is described.

The necessary braking torque M determined by means of the model 42 is supplied to the elevator control 44 in the embodiment shown. The subsequent processing of the determined braking torque M can in principle also take place outside the elevator control 44, which includes an implementation of conventional functions of an elevator control 44 not considered here and correspondingly not described here, for example still in the context of the model 42 or in a braking control. The model 42 can of course in principle also be implemented as a partial functionality of the elevator control 44. For the further description, the configuration shown as an example is assumed.

Within the elevator control 44 or at most a corresponding brake control, the determined necessary braking torque M is processed by means of a functional unit, which can be understood as a further model. The functional unit includes an implementation of the braking characteristics of the braking device 22 and is referred to below as the braking device model 46 in order to distinguish it from the model 42 of the elevator system 10. By means of the Brake device model 46, the determined necessary braking torque M is converted into a manipulated variable required to obtain a manipulated variable. In the braking device model 46 there is a theoretical relationship which stores the relationship between the manipulated variable and braking torque M, or in other words the braking characteristic of the braking device. This can be done using a table (look-up table) stored as an implementation of the braking device model 46 or a mathematical relation stored as an implementation.

In the case of a braking device 22, which comprises an electromagnet 32 as a means for releasing the brake, the manipulated variable is the coil current with which the electromagnet 32 is acted upon. The manipulated variable is the amplitude of the coil current / or the duty cycle in the case of an electromagnet 32 to which a pulse-width-modulated coil current is applied. The table or the mathematical relation of the brake device model 46 takes into account the spring force of the spring 30 and the electromagnetic force which counteracts the spring force and results from a respective manipulated value. With a different type of braking device and a different way of releasing the brake, a different manipulated variable results and correspondingly a different manipulated variable. However, the principle remains the same. Controls of the electromagnet 32 via a pulse width modulated (PWM) coil current have been proven. Of course, other types of controls, such as a leading edge or leading edge control, are also known to influence a strength of a magnetic field.

When represented in Figure 3 A configuration is shown in which a coil current / is determined as a manipulated value by means of the brake device model 46 on the basis of the previously determined necessary braking torque M , which is subsequently converted into a pulse-width modulated control signal 40.1 by means of a pulse width modulator 48. The control signal 40 is shown in FIG Figure 3 on the one hand, shown symbolically as a square-wave signal or as a pulse-width-modulated control signal 40.1 and on the other hand as a control signal 40 supplied to the braking device 22.

When the braking device 22 is actuated with the actuation signal 40 generated in this way, there is a specific actual braking effect and a resulting actual cabin deceleration Vi. This can be measured by means of an acceleration sensor or at least indirectly measured by means of an incremental encoder or another displacement measuring system, such as, for example, by means of a coded displacement transducer on the basis of which a position of the elevator car 12 can be determined. When the elevator system 10 is braked, namely when the elevator car 12 is braked by means of the braking device 22, the respective actual car deceleration Vi is determined. When determining the actual cabin deceleration Vi , zones with an unsteady deceleration curve, such as occur, for example, at the beginning of the braking process, are not taken into account. To determine the actual cabin deceleration Vi is only a trustworthy Area used. If unexpected changes are detected during the braking process, the measurement may not be used. Unexpected changes can be caused, for example, by an error or discontinuity in a management system. If the actual cabin deceleration Vi is determined in this way, an actual braking torque M _{M is} calculated on the basis of this actual cabin deceleration Vi and using the model 42. This actual braking torque M _M thus determines an operating point or a test point of a braking characteristic. On the basis of this working or test point, the braking characteristic stored in the braking device model 46 is calibrated or recalibrated in a calibrator 50. Such a calibration process is related to Figure 5 explained in more detail.

When represented in Figure 4 which is essentially a repetition of the in Figure 3 As shown in the details shown, the pulse width modulator 48 is a partial functionality of the brake device model 46, so that it includes, for example, a table or a mathematical relation on the basis of which a determined necessary braking torque M supplied to the brake device model 46 on the input side into a duty cycle of a pulse width modulated control signal 40.1 for controlling the brake device 22 is implemented. Even with such a configuration, the calibration is carried out on the basis of the determined actual cabin deceleration Vi and the actual braking torque M _M determined therefrom .

When represented in Figure 4 is also indicated that the recalibrated braking characteristic determined from the actual braking torque M _M (see graph K3 in Fig. 5 ) is compared with at least one limit value G by means of a comparator 51. The limit values G are as in the following description Fig. 5 actually explains limit characteristics K2 ', K2 ", which determine upper and lower limit values which the recalibrated brake characteristic K3 must not exceed or fall below. The limit characteristics K2', K2" are selected such that their exceeding indicates an exceptional situation. In such a case, at least one in the representation in Figure 4 Actuator 52 shown in the form of an optical display element, by means of which operating or service personnel of the elevator system 10 is made aware of the exceptional situation. Other actuators, for example an actuator for sending an acoustic warning signal or an actuator that triggers the sending of a warning in the form of an email, SMS or the like, are of course also possible as an alternative or cumulatively. If the comparator 51 determines that the recalibrated braking characteristic K3 remains within the limits determined by the limiting characteristics K2 ', K2 ", this recalibrated braking characteristic K3 is stored in the braking device model 46 and released for use in future braking processes.

In Figure 4 Finally, a database 54 is also shown, by means of which the data used and / or resulting in the operation of the elevator system 10 and in the activation of the braking device 22 are obtained Sizes can be recorded for archiving purposes. At least the actual cabin deceleration Vi, the corresponding previously described parameters and the resulting calibration are recorded.

Figure 5 represents a possible calibration process of the control signal 40 in a schematic manner. The braking device model 46 comprises a theoretical relationship, represented by the graph K1, of the braking torque M caused by the braking device 22 as a function of the control signal 40. The braking torque M in this context is also a braking relation to understand. The in the Figure 5 The scaling shown is not an absolute value specification, but rather a size specification relating to the braking torque M and a size specification relating to the effective braking torque and a size specification relating to the control signal 40. The theoretical relationship between the control signal 40 and the resulting braking torque M can be represented by a parametric function. An intersection of the graph K1 with the zero line of the braking torque M results in the so-called closing point P1 of the braking device 22. If the control signal 40 exceeds this closing point P1, the electromagnet lifts the pressure element 24 away from the counter surface and a resulting braking torque M is omitted or becomes zero. However, if the control signal 40 is reduced and falls below the closing point P1, the braking device 22 is in the control range, where a braking torque M corresponding to the control signal 40 is established. If the control signal 40 reaches the value zero, the electromagnet is switched off. This results in the intersection of the graph K1 with the zero line of the control signal 40. This intersection can be referred to as the operating point P2 of the braking device 22. At the operating point P2, the spring force of the spring 30 alone determines the braking torque M.

$$M\stackrel{\wedge}{=}\mathrm{FF}-\left(\mathrm{FM}\times I^2\right)$$

The braking characteristic or also the theoretical relationship between the control signal 40 and the resulting braking torque M, represented by the graph K1, can thus be represented as follows: $$\mathrm{braking\; torque}M=\mathrm{Spring\; force\; value}\mathrm{FF}-\left(\mathrm{Magnetic\; force\; value}\mathrm{FM}\times \mathrm{square}\mathrm{of}\mathrm{control\; signal}40\right)$$

$$M\stackrel{\wedge}{=}\mathrm{FF}-\left(\mathrm{FM}\times I^2\right)$$

• der Federkraftwert FF ein von der Federkraft der Feder 30 bewirkter Bremsmomentanteil,
• der Magnetkraftwert FM ein abhängig vom Ansteuersignal 40 vom Elektromagnet bewirkbarer Bremsmomentanteil, und
• das Ansteuersignals 40 ist ein dem Spulenstrom / entsprechendes Signal.

It is

• the spring force value FF is a braking torque component caused by the spring force of the spring 30,
• the magnetic force value FM is a braking torque component which can be brought about by the electromagnet as a function of the control signal 40, and
• the control signal 40 is a signal corresponding to the coil current.

Taking into account expected deviations in the elevator system, such as friction influences, mass inaccuracies and tolerances of the components used, the theoretical relationship is subject to a tolerance range K2. The tolerance range is in the Figure 5 by Tolerance graphs K2 ', K2 "are limited. The tolerance graphs K2', K2" define the limit values G or the tolerable limit characteristics K2 ', K2 ". When the braking device 22 is activated with a control signal 40, which is defined based on the theoretical relationship K1, This results in a specific actual braking effect and a resulting actual car deceleration Vi, from which the actual braking torque can be calculated using the model 42 of the elevator system 10. This results in new test points T1, T2, Tn for each subsequent braking. A calibrated braking characteristic K3 is generated using the theoretical relationship on which the graph K1 is based, T2, Tn calculation can be determined. Here, the calibrated braking characteristic K3, which runs as close as possible to the data points, is searched for using the theoretical relationship represented by the graph K1, predetermined data points and the further recorded test points T1, T2, Tn. As long as this calibrated braking characteristic K3 lies within the tolerance range K2 determined by the limiting characteristics K2 ', K2 ", further braking operations are carried out using the calibrated braking characteristic K3. With each additional braking, the accuracy of the car deceleration can be improved.

The following test points T1, T2, Tn can be weighted. This means that the test points recorded during operation are weakened in relation to the theoretically predetermined braking characteristics, so that changes in the braking characteristics or corresponding calibrations change only slowly. If the calibrated braking characteristic K3 leaves the tolerance range K2, an assessment of the braking system by a specialist is required and corresponding warning messages are output. A multi-level reporting system can be used. A specialist can be informed in a first stage, a service can be requested in a second stage and an elevator system can be shut down in a further stage.

The in the introduction and based on the representations in the Figures 3 . 4 and 5 Approach for controlling a braking device 22 of an elevator installation 10 described with further details is implemented, for example, in software and is executed during operation of the elevator installation 10 by executing a control program containing an implementation of the method proposed here. The the Figures 3 and 4 The functional units shown and explained here are representatives for a corresponding software functionality of the control program, for example a software functionality functioning as a model 42 of the elevator installation 10, a software functionality functioning as a braking device model 46 and a routine implemented as a calibrator 51 and implemented in software, which in the example for calibration of the determined necessary braking torque M _{M is} used, so that the recalibrated braking characteristic K3 can be supplied to the braking device model 46.

Although the invention has been illustrated and described in detail by the exemplary embodiment, the invention is not restricted by the disclosed example or examples and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention.

Individual aspects of the description submitted here that are in the foreground can thus be briefly summarized as follows: A method for controlling a braking device 22 of an elevator system 10 and an elevator system 10 with means 42, 44, such as the model 42 of the elevator system 10 and the elevator controller 44, are specified to carry out the method, wherein the braking device 22 comprises at least one automatically releasable pressure element 24 intended for effecting a braking effect and means 32 for automatically releasing the or each pressure element 24, one of which by means of a model 42 of the elevator system 10, a respective direction of travel R. State of charge m and a desired cabin deceleration Vs, a braking torque M of an elevator car 12 of the elevator installation 10 is determined, wherein on the basis of the braking torque M a control signal 40 for controlling a device acting as means 32 for automatically releasing the or each pressure element 24 ng is generated and fed to it, wherein when the elevator system 10 brakes, an actual car deceleration Vi is determined and an actual braking torque M _{M is} determined, and a calibration, namely a recalibration of a braking characteristic, takes place on the basis of an actual braking torque M _{M that} actually corresponds to the control signal 40.

The quantity referred to as braking torque M can also be a braking relation. The related Figure 5 The quadratic function shown can also be another parametric function.

Claims (10)

1. Method for driving a brake device (22) of a lift system (10),
   wherein the brake device (22) comprises at least one automatically releasable pressure element (24), which is intended to effect a braking action, and also means (32) for automatically releasing the or each pressure element (24),
   wherein a respectively required braking torque (M) of a lift car (12) of the lift system (10) is ascertained by means of a model (42) of the lift system (10), a respective direction of travel (R), a state of charge (m) and a desired car deceleration (Vs),
   wherein a drive signal (40) for driving a device, which functions as a means (32) for automatically releasing the or each pressure element (24), is generated on the basis of the braking torque (M) and is supplied to said device,
   wherein, when the lift system (10) is braked, an actual car deceleration (Vi) is ascertained and
   wherein calibration of a braking characteristic (K3) is performed on the basis of the ascertained actual car deceleration (Vi),
   specifically calibration of the ascertained required braking torque (M) or calibration of the drive signal (40) which is generated on the basis of the ascertained required braking torque (M).
2. Method according to claim 1, wherein the calibrated braking characteristic (K3) is evaluated in relation to tolerable limiting characteristics (K2', K2"), and the calibrated braking characteristic (K3) is approved for further use, if the calibrated braking characteristic (K3) is within the limits defined by the limiting characteristics (K2', K2").
3. Method according to claim 2, wherein a warning message is output as soon as the calibrated braking characteristic (K3) goes beyond the limits determined by the limiting characteristics (K2', K2").
4. Method according to claim 1, claim 2 or claim 3, wherein, proceeding from the required braking torque (M), a pulse-width modulated drive signal (40.1) is generated as the drive signal (40) on the basis of the calibrated braking characteristic (K3).
5. Method according to any of the preceding claims, wherein, during an initialization phase of the brake device (22), a predefined or predefinable number of braking processes and respective calibration of the braking characteristic (K3) are carried out.
6. Method according to any of the preceding claims, wherein an expected braking period is calculated in each case on the basis of the desired car deceleration (Vs), and wherein, after the expected braking period has elapsed, the drive signal (40) is predefined such that the brake device (22) generates a maximum braking torque (M).
7. Lift system (10) comprising at least one lift car (12) and a brake device (22), which is intended for braking the elevator car (12), and a model (42) of the lift system (10) and a lift control unit (44) for executing the method according to any of the preceding claims.
8. Lift system (10) according to claim 7, wherein the brake device (22) comprises at least one electromagnetically disengageable spring-actuated brake (24, 30) and an electronically drivable electromagnet (32) for disengaging the spring-actuated brake (24, 30).
9. Computer program having program code means for carrying out all the steps from each of claims 1 to 6 when the computer program is executed by means of a lift control unit (44) of a lift system (10).
10. Lift system (10) according to either claim 7 or claim 8, comprising the lift control unit (44), which functions as a means for executing the method for driving the brake device (22), wherein a computer program according to claim 9, which functions as a control program and can be executed by means of the lift control unit (44), is loaded into a memory of the lift control unit (44).

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