EP0976675A1 - Method of force limitation for automatic elevator doors - Google Patents

Abstract

The drive force profile in normal operation, interfering forces being absent, is determined from a mathematical model. This profile is compared with the actual drive force measured during use. Departures of given magnitude, which are triggered by mechanical interference, stop or reverse door travel.

Description

The invention relates to a method for limiting force for automatic elevator doors with a door operator consisting of control, motor and drive mechanism for Movement of a cabin door and a landing door according to one the speed profile corresponding to the door position and force course from an open position to a Closed position or vice versa, the force curve door parameters that change over time is customizable and the doors during the movement process in the event of interference caused by an obstacle are stopable and / or reversible.

From the patent DE 39 21 158 is one Control device for a by means of a DC motor powered articulated door known. The driving torque is that Motor armature current proportional. In a storage device are the motor current curve depending on the angle of rotation the door in trouble-free operation and with the maximum permissible torque saved. These current values can be obtained mathematically or experimentally. Around to consider friction losses acting on the door, the formation of the setpoint armature current is the above the stated current value is added to a moving average, which results from the actual value of the armature current in obstacle-free operation. The determination of the The setpoint is after every flawless opening and Closing the door provided. Enter the door Obstacle, the actual value of the armature current increases disproportionately. This is used in the control device Actual value compared to the setpoint. If the actual value is above the permissible setpoint, the armature current and thus the door drive torque is reduced.

A disadvantage of the known device is that complex and extensive storage of the for Average necessary position-dependent Current curves for the entire driving range of the door.

The invention seeks to remedy this. The invention, as characterized in claim 1, solves the problem to avoid the disadvantages of the known device and a method for driving force limitation with a optimized signal-to-noise ratio and increased safety for elevator users.

The advantages achieved by the invention are in essential to see that a compact form of Description of the interference-free drive force curve is possible. This can be an automatic, optimal Setting of the driving force limit reached and the Commissioning effort can be reduced. Another advantage is that a force limit isn't just for a particular one Target speed function of the door is available, but also for deviating courses, for example at reduced speed or increased acceleration can be provided without a new learning trip beforehand perform.

When closing the door there is a risk that the increasingly smaller door gap obstacles like for example people or objects are located and can be pinched. In the door opening process the risk that, for example, children's hands or flat Objects between those moving against each other Door leaf or get between door leaf and door frame can.

The method according to the invention relates to the Door closing process as well as the door opening process. Force limitation means a when closing the door Limitation of the closing force or a limitation of the Opening force during the opening process. Force curve relates the force curve during the door closing process or during the door opening process.

Fig. 1

eine schematische Darstellung des erfindungsgemässen Verfahrens und

Fig. 2

statistische Funktionen zur Auswertung der Differenz zwischen Soll- und Istschliesskraftwerten.

The invention is explained in more detail below with reference to drawings which show an exemplary embodiment. Show it:

Fig. 1

a schematic representation of the inventive method and

Fig. 2

statistical functions for evaluating the difference between target and actual closing force values.

Fig. 1 shows a system for the operation of an automatic Elevator door consisting of a setpoint generator 1 for the Speed, an actual value recorder 2 the Speed / door position, a motion controller 3, one Speed generator 4 in the form of a door drive consisting of control, motor and drive mechanics as well an actual value detector 5 for the generated or applied Driving force. The drive or motor power is the applied by the engine, taking into account the realized gear ratios converted to the door Force designated. The closing force or opening force is the force that is applied during a closing process or Opening process from the door edge or door on Obstacle is exercised. A driving force model 6 for that Driving force calculated on the basis of a mathematical Model and the determined door parameters which in the Driving force to be applied without interference. On Limit value generator 7 calculated from the Upload model value and a permissible interference force a force limit value, which by means of a comparator 8 Actual value of the driving force or the applied Driving force is compared. When crossing of the force limit, the door is stopped and / or Reverse movement triggered.

With the help of a mathematical model of the door and drive components are the driving force model 6 the driving force to be used. This mathematical model determined using Equations of motion and the previously determined door parameters that at a certain acceleration and at a certain speed under normal, undisturbed Driving force to be applied. The The force limit is determined from the driving force to be applied and the maximum permissible interference force. Meets the Door on an obstacle while moving, so when Exceeding the force limit by the applied Driving force a stopping and / or reversing the Elevator door raised to the safety of elevator users to ensure.

The mathematical model can be fixed or designed adaptively in a further embodiment be, being an adaptation to the during operation occurring parameter changes takes place.

The model can be based on differential equations can be (explicitly) realized. The explicit mathematical Model is based on Newton's equations of motion for the door mechanism. These are here for a simplified one Model of the door mechanism specified.

v ˙_T

die Beschleunigung,

v_T

die Geschwindigkeit der Türkante,

F_MT

die vom Motor aufgebrachte, unter Berücksichtigung der kraftübertragenden und kraftumformenden Mechanik auf die Türkante/Tür umgerechnete Antriebskraft,

F_R

die als konstant angenommene Summe aller auf die Türkante umgerechneten Gleit- und Rollreibungskräfte der Türmechanik,

sign (v_T)

die Signumfunktion, die für v_T>0 den Wert 1 und für v_T<0 den Wert -1 aufweist.

g

die Schwerebeschleunigung 9,81 m/s²,

m_G

die Masse des Gegengewichtes und

m_GT

die Summe der unter Berücksichtigung der kraftübertragenden und kraftumformenden Mechanik auf die Türkante/Tür umgerechneten Massen aller bewegten Teile (Türflügel, Rollen, Zahnriemen, Riemenscheiben, Stahlseile, Gegengewicht, Rotor des Motors, usw.) bedeuten.

For the following considerations, all forces and speeds in the direction of the closing door are defined positively. If the mechanics is modeled as a one-mass system with the total door mass m _GT converted to the door edge, the following relationship between speed and force results (Newtonian equation of motion, direct force transmission between counterweight and door edge provided): v T = F MT - F R · Sign (v T ) + g · m G m GT in which

v ˙ _T

the acceleration,

v _T

the speed of the edge of the door,

F _MT

the drive force applied by the motor, taking into account the force-transmitting and force-converting mechanics, converted to the door edge / door,

F _R

the sum of all sliding and rolling friction forces of the door mechanics, which is assumed to be constant on the door edge,

sign (v _T )

the signum function, which has the value 1 for v _T > 0 and the value -1 for v _T <0.

G

gravitational acceleration 9.81 m / s ² ,

m _G

the mass of the counterweight and

m _GT

the sum of the masses of all moving parts (door leaf, roller, toothed belt, pulley, steel cable, counterweight, motor rotor, etc.) converted to the door edge / door, taking into account the force-transmitting and force-converting mechanics.

By changing over to the force F _MT you get: F MT = v T · M GT + F R · Sign (v T ) + g · m G v T ≈ v T (t) - v T (t - T) T

This is a mechanical door model in an explicit form, at which the physical parameters are still recognizable as such are.

According to the equation given, the driving force to be applied at any time can be calculated depending on the parameters and the acceleration v ˙ _T. The acceleration is approximately calculated from the speed values, as shown in equation [3], where T is a suitably selected sampling time.

Equations [2], [3] can be easily programmed and provide the driving force model value for force monitoring. If the parameters F _R , m _G and m _{GT are set} once, for example during the manufacture or commissioning of the door, the model is fixed. If the parameters of the model are automatically adapted to the actual parameters of the door mechanics during operation of the door, this is called an adaptive model.

The setpoint generator 1 generates one Speed setpoint as a function of time or Way or the door position. The motion controller 3 can for example a speed / position controller, based on measured speed / position information generates a speed specification.

The mathematical model represents the dependency of the respective generated driving force from the acceleration, the speed setting and the door position. From mathematical model, the motor force is calculated the without obstacle the predetermined speed curve generated. This normal course depends, for example, on the given acceleration, the characteristic of the Speed generation, the friction forces, the mass of the moving parts and the parameters of the mechanics and the Friction in mechanics.

The one to be generated, generated by the driving force model 6 The driving force is during the operation of the door Changes due to wear and aging exposed. Therefore, the driving force model 6 can be designed that a slow adaptation of the to be applied Driving force in the course of changes he follows. The actual value of the driving force or applied driving force can be in connection with the target / actual speed be evaluated to determine the effective moving mass, the closing weight of the door and the One-time or ongoing frictional force during operation determine.

To obtain the unknown physical parameters of the explicit model, test drives are carried out in which the measured values for the motor force converted to the door edge / door and the speed of the door edge / door are recorded and saved periodically. According to equation [1], the acceleration depends on the engine power. The right side of the equation [1] contains a component that is linear to the force and a constant component. v T = 1 m GT · F MT + - F R · Sign (v T ) + g · m G m GT = a · F MT + b

If the variables v _T and F _{MT are recorded} over time for an opening or closing process, the coefficients a and b of the linear equation [4] can easily be determined, for example by means of linear regression. The values determined for a closing process are denoted as a _s and b _s , those for an opening process as a ₀ and b ₀ . Then: a s = a 0 = 1 m GT m GT = 1 a s = 1 a 0 b s = - F R · Sign (v T ) + g · m G m GT = - F R · (-1) + g · m G m GT b 0 = - F R · Sign (v T ) + g · m G m GT = - F R · (-1) + g · m G m GT m G = (b s + b 0 ) · M GT 2g F R = (b 0 - b s ) · M GT 2nd

So all parameters of interest are explicit Known model. (The gravitational acceleration g is called known provided). Do the described Parameter identification only once, it will resulting model fixed. The measured values can but also recorded and processed during operation become. The current parameters obtained in this way can be used for Tracking the model parameters and adapting to slow changes in door mechanics, for example through wear and soiling. In in this case the model is adapted.

The mathematical model can also be used as an implicit model will be realized. An implicit mathematical model also generated for a given acceleration curve a reference value of the engine power, but without doing so on the vivid physical parameters to have to fall back. An implicit mathematical Model can be made through an artificial neural network being represented.

An implicit model is through a training phase prepared, in which the behavior of the model by a Larger number of examples for the input / output behavior is specified. This sample data are generated by a real system whose behavior to be mimicked by the model, with different Input data is stimulated and at the same time the Input signal and the output signals representing the response of the system show be recorded. In the specific case you become a number of opening and closing movements the door and the ones that occur Record measured value curves. The internal parameters of the implicit models are optimized until the Model for all input data similar output data generated like the real model system until model and Reality sufficiently similar.

For example, an asynchronous motor can be used as the speed generator 4 in connection with a frequency converter with a rotor flux-oriented current control and superimposed speed control implemented thereon, the torque-forming current component i _sq , which is orthogonal to the rotor flux, being usable as an internal variable.

To generate the torque in a rotary Asynchronous motor is the generation of one around the motor axis rotating magnetic field required. A particularly simple description of the relationships between Motor current, magnetic flux and motor torque is through Equations possible if you have a Performs coordinate transformation.

The stator currents measured in the three motor phases overlap to form a resulting current vector i _s , which is characterized by the amount and the angle with respect to the first motor winding axis. The coordinate transformation consists in not selecting the position of the first winding axis as the reference point, but the current magnetic flux in the rotor of the machine. The current in the stator i _s can then be broken down into a component i _sd parallel to the rotor _flux and a component i _sq perpendicular to it. The amount of rotor flux can be kept constant by the suitably controlled current component i _sd . The proportionality between i _sq and the applied engine torque then applies, so that i _{sq is} a measure of the driving force acting on the door edge / door.

For example, a can also be used as the speed generator 4 Asynchronous motor in connection with one on it implemented U / f control are used, the detected slip as a measure of the applied Driving force serves.

s

der Schlupf,

n_s

die Synchrondrehzahl des umlaufenden magnetischen Feldes,

n

die mechanische Drehzahl der Motorwelle,

w_s

die Synchronkreisfrequenz des magnetischen Feldes,

w

die mechanische Kreisfrequenz,

f_s

die aktuelle Synchron- bzw. Ausgangsfrequenz des Frequenzumrichters und

zp

die Polzahl des verwendeten Motors ist.

The slip s is defined according to the following equation: s = w s - w w s = n s - n n s n s = f s / zp in which

s

the slip,

n _s

the synchronous speed of the rotating magnetic field,

n

the mechanical speed of the motor shaft,

w _s

the synchronous angular frequency of the magnetic field,

w

the mechanical angular frequency,

f _s

the current synchronous or output frequency of the frequency converter and

zp

is the number of poles of the motor used.

M_K

das Kippmoment und

s_K

der Kippschlupf ist.

According to the well-known Kloss formula: m M = 2M K s / s K + s K / s = 2M K · S s 2nd / s K + s K in which

M _K

the overturning moment and

s _K

the tipping slip is.

Both sizes are for a given motor and V / f characteristic control constant.

For small slip amounts (s <s _K ) the approximation applies: m M = 2M K · S s 2nd / s K + s K ≈ 2M K s K · S so that from a measured mechanical speed n and the known frequency of the output voltage f _{s of} a frequency converter the slip and from this in turn the motor torque according to the formula m M = 2M K s K · f s / zp - n f s / zp can be calculated.

For example, a can also be used as a speed generator voltage and frequency controlled asynchronous motor used the measured stator current as a measure of the driving force serves.

zp

die Polpaarzahl,

I_s

der Betrag des Ständerstromes,

L_m

die Hauptinduktivität des Motors,

L_s

die Ständerinduktivität des Motors,

U_nom

die Nennspannung des Motors und

f_nom

die Nennfrequenz des Motors ist.

The mean value of the current through the stator winding of the asynchronous machine in the case of V / f control is from the applied motor torque m _M using the formulas m M = -K · I rα I. s = I. µ 2nd + I rα 2nd dependent, where · I _{rα is} the current component _{proportional to} the _torque over time, K is a constant dependent on the motor data and I _{µ is} the constant magnetizing current. The amount of the moment thus results from the measured amount of current m M = -K · I rα m M = 1 / K I. s 2nd - I µ 2nd K = 3/2 zp L m · U nom L s · 2π · f nom I. µ = U nom 2π · f nom · L m in which

zp

the number of pole pairs,

I _s

the amount of stator current,

L _m

the main inductance of the motor,

L _s

the stator inductance of the motor,

U _nom

the nominal voltage of the motor and

f _nom

is the nominal frequency of the motor.

This is the amount of drive torque from the measured current amount can be calculated. Other arrangements and Control methods, such as synchronous drives with Measurement of the magnet wheel angle or the stator current amount or DC drives with stator current measurement, etc., the a conclusion on the actually from the actuator allow applied force are as Speed generator also possible.

For example, a can also be used as the speed generator 4 Synchronous motor can be used.

The limit value generator 7 calculates from that by means of mathematical model determined driving model value and a permissible interference force a force limit value. in the In the simplest case, this is done by adding the per Regulation stipulated maximum permissible interference of for example 120 N.

As a more sensitive solution for determining the Force limit can be a statistical evaluation process for example according to a Gaussian normal distribution be used. The Gaussian normal distribution is only one of many possible distribution functions. Exponential, Weibull or equal distribution are also applicable. All of these functions have a density function and a distribution function, the calculated ones Numerical values can of course be different. Through the statistical evaluation of the difference between the actual value the driving force and that of the mathematical model delivered value of the driving force can be determined how good the measured values with the theoretical values. Under the assumption a Gaussian normal distribution of the difference values itself, as shown in FIG. 2, from the determined Standard deviation determine what percentage of all Difference values exclusively as a result of random Influences exceed a certain limit without that is actually an obstacle in the course of Closing process has occurred. Conversely, the Specify and use the minimum limit at which the Probability of a mistakenly triggered Reversing is acceptably small.

It is assumed for a larger number of measurements found that the difference values around the mean 0 the density function phi (z) (curve 9) of the normal distribution scatter with a standard deviation of 10 N. According to the distribution function Phi (z) (curve 10) the Normal distribution is therefore 50% of all difference values less than 0. 84% of all limit values are less than 10 N, 97.7% are less than 20 N and 99.86% are less than 30 N. If you set the limit 30 N higher than that of mathematical model delivered setpoint the Door closing force, only 0.14% of all measured values are random disturbances exceed the limit. In order to can be achieved without sacrificing reliability Realize lower trigger threshold and that Reduce risk of injury. Based on the current statistical evaluation of the difference values can be a Adaptation takes place during operation.

Claims (10)

Force limitation method for automatic elevator doors with a door drive consisting of control, motor and drive mechanism for moving a car door and a landing door according to a speed curve and force curve corresponding to the door position from an open position to a closed position or vice versa, the force curve changing over time Door parameters can be adjusted and the doors can be stopped and / or reversed during the movement process in the event of an interference force triggered by an obstacle,
characterized,
that the driving force curve to be applied in the interference-free operation is determined using a mathematical model for the door drive and is compared with the driving force curve generated by the door drive and
that deviations of a certain size triggered by the interference force between the force curve to be applied and the force curve generated stop and / or reverse the doors. Method according to claim 1,
characterized,
that the mathematical model is based on Newton's equations of motion for door mechanics. Method according to claim 2,
characterized,
that the mathematical model is an adaptive model in which the parameters are automatically adapted to the actual parameters of the door mechanics while the door is in operation. Method according to claim 1,
characterized,
that the mathematical model can be represented by an artificial neural network, the model being prepared by a training phase in which the model mimics a real system. Method according to claim 1,
characterized,
that a voltage- and frequency-controlled asynchronous motor is provided to generate the force curve, the detected motor slip serving as a measure of the driving force. Method according to claim 1,
characterized,
that a voltage- and frequency-controlled asynchronous motor is provided to generate the force curve, the detected stator current amount serving as a measure of the driving force. Method according to claim 1,
characterized,
that an asynchronous motor fed by a frequency converter is provided for generating the force profile, the current component i _sq , which is orthogonal to the rotor flux, being used as a measure of the driving force. Method according to claim 1,
characterized,
that a synchronous motor is provided to generate the force curve. Method according to claim 1,
characterized,
that a force limit value is determined from the drive force model value determined by means of the mathematical model and a permissible interference force, the doors stopping and / or reversing when the force limit value is exceeded. Method according to claim 9,
characterized,
that the force limit value is determined using a statistical evaluation method based on a density and distribution function.

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