Detecting a collision during operation of an automatic door system

Abstract

The present invention relates to collision detection in operation of a door in an automatic door system. The collision detection is performed by monitoring a net rotatum deviation of the automatic door system while operating the door and upon the net rotatum deviation exceeding a threshold for collision, issuing a collision signal. The threshold for collision may be set by detecting an extreme net rotatum deviation of the automatic door system during a collision free operating cycle of the automatic door system and determining the threshold for collision based on the detected extreme net rotatum deviation.

Description

[0001] DETECTING A COLLISION DURING OPERATION OF AN AUTOMATIC DOOR SYSTEM

[0002] TECHNICAL FIELD

[0003] The present invention relates to collision detection in operation of a door in an automatic door system. Especially, a method for detecting a collision with an obstacle during operation of the automatic door system is presented. A door operator configured to perform the collision detection is also presented.

[0004] BACKGROUND ART

[0005] A door with a door operator, also known as an automatic door opener and / or closer, is a type of door operation system designed to open and / or close a door automatically. Such systems are typically referred to as an automatic door system. Automatic door systems are commonly used in commercial buildings, hospitals, airports, and other public spaces to provide convenient and accessible entry and exit points.

[0006] In order to detect and even possibly avoid collisions with a user, an automatic door system is typically equipped with safety sensors. Such safety sensors are configured to detect if a user is coming too close to the door. However, such safety sensors are in many situations too sensitive resulting in unwanted interruptions of the operation of the automatic door system. For example, a revolving door often stops when too many people try to pass it in the same section of the revolving door, because one of them will come too close to a door leaf. According to another example, a swing door often stops opening if a user approaches it from the side in which they open, e.g., if the approach a swing door from the outside of the building when the swing door swings outwards.

[0007] Another issue is that wind may affect the automatic door system making collision monitoring and collision management troublesome.

[0008] Accordingly, there is a need in finding solutions to reduce unwanted interruptions of automatic door systems but at the same time safeguard so that the door system does not injure users of the system or that the system itself gets damaged from collisions with obstacles.

[0009] SUMMARY OF THE INVENTION

[0010] The present invention is set out in the appended set of claims. According to a first aspect, a door operator configured to operate a door of an automatic door system is presented. The door operator comprises: a door mechanism configured to operate a door of the automatic door system; an electric motor configured to drive the door mechanism; and control circuitry. The control circuitry is configured to execute: a monitoring function configured to monitor a net rotatum deviation of the automatic door system while the electric motor is driving the door mechanism for operating the door; and a collision detection function configured to, upon the net rotatum deviation exceeding a threshold for collision, issue a collision signal.

[0011] According to the previous standard for automatic door system, EN 16005:2012, it is stated that any contact between the door and users is to be prevented. In order to avoid collisions, an automatic door system fulfilling the requirements of the EN 16005:2012 standard is typically equipped with safety sensors detecting possible collisions between the door and an obstacle in an operation region of the door. However, according to the latest version of the standard for automatic door systems, EN 16005:2023, contact between a door and an obstacle is now acceptable if an on-site risk analysis shows that the consequences are low enough. This allows for collisions to occur as long as it can be safeguarded that the collision can be controlled so that the object causing the collision is not damaged. By implementing the collision detection as presented herein, consequences of a collision can be reduced drastically. Hence, automatic door systems can be installed without expensive and power consuming safety sensors. This may save cost, material resources, energy consumption and installation time. Moreover, functionality of the automatic door system may be improved since light collisions between a user and the door upon operation may be allowed.

[0012] Further, the present invention allows the automatic door system to operate without a safety sensor. This is due to collisions with obstacles during an opening and / or closing cycle being detectable by the monitoring of the net rotatum deviation. By operating the automatic door system without a safety sensor, electrical energy consumed by the safety sensors will be saved. Accordingly, a more energy efficient automatic door system may be provided. This is especially true when the automatic door system is in standby mode. The safety sensors typically have an activation time in the order of a few seconds. As a result of this, it is necessary that the safety sensors are kept active constantly, so to avoid a lagging duration upon activation of the automatic door system. Saving energy in standby mode is beneficial since authorities, such as the European Union, are aiming at introducing regulations at reducing electrical power consumption of electronic devices. Especially, regulations directed towards reducing electrical power consumption for electronic devices when not in use.

[0013] Further, the present invention allows for prevention of unnecessary heat exchange through a door unnecessarily kept open and does not close due to e.g. a safety sensor identifying an obstacle in the vicinity of the door, but not in the doorway.

[0014] The control circuitry may further be configured to execute a calibration function configured to set the threshold for collision by: detecting an extreme net rotatum deviation of the automatic door system during a collision free operating cycle of the automatic door system; and determining the threshold for collision based on the extreme net rotatum deviation.

[0015] An operating cycle of the automatic door system may comprise a plurality of operation phases. The calibration function may be configured to detect an extreme net rotatum deviation for each such operation phase and determine a threshold for collision for each such operation phase. Hence, a threshold for collision may be tailored for each operation phase allowing for increased sensitivity in the collision detection.

[0016] Determining the threshold for collision may further comprise, during the collision free operating cycle of the automatic door system, recording the net rotatum deviation of the automatic door system while operating the door to follow a predetermined speed reference over time. During the "normal" operation, i.e. in collision detecting mode, the same predetermined speed reference over time is also to be followed by the automatic door system. Doing so, may allow setting of the threshold for collision to be made more accurately, increasing the sensitivity in the collision detection.

[0017] The control circuitry may further be configured to, in response to a collision signal, execute a termination function. The termination function may be configured to terminate the operation of the automatic door system.

[0018] The control circuitry may further be configured to, in response to the collision signal, execute a reversing function. The reversing function may be configured to reverse the driving of the electric motor. This mode of operation allows for a user to reverse operation of a door just by interacting with the door by their hand. Hence, a user may cause a closing door to reopen by slightly pushing with their hand against the closing edge of the closing door, which is more intuitive than looking for a button located somewhere around the door. According to a second aspect, an automatic door system comprising the door operator according to the first aspect and a door is presented. The above-mentioned features and possible advantages of the door operator, when applicable, apply to this second aspect as well. In order to avoid undue repetition, reference is made to the above.

[0019] According to a third aspect, a method for detecting a collision during operation of an automatic door system is presented. The method comprises: monitoring a net rotatum deviation of the automatic door system while operating a door of the automatic door system; and upon the net rotatum deviation exceeding a threshold for collision, issuing a collision signal. The above-mentioned features and possible advantages of the door operator, when applicable, apply to this third aspect as well. In order to avoid undue repetition, reference is made to the above.

[0020] A further scope of applicability will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples are given by way of illustration only.

[0021] It is to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It must be noted that, as used in the specification and the appended claim, the articles "a", "an," "the," and "said" are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings do not exclude other elements or steps.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other aspects will now be described in more detail, with reference to appended figures. The figures should not be considered limiting; instead, they are used for explaining and understanding.

[0024] As illustrated in the figures, the sizes of layers and regions may be exaggerated for illustrative purposes. Like reference numerals refer to like elements throughout.

[0025] Fig. 1 schematically illustrates an automatic door system configured to implement a collision detection in accordance with the present invention. Fig. 2a illustrates a representation of a measurement of net rotatum deviation for an automatic door system as a function of time for a closing cycle of a door without any interference, i.e. without any collision.

[0026] Fig. 2b illustrates a representation of a measurement of the net rotatum deviation as a function of time for the same automatic door system as for the one in Fig. 2a, but this time a collision occurs.

[0027] Fig. 3 is a block diagram of a method for detecting a collision during operation of an automatic door system.

[0028] Fig. 4a illustrates a representation of a measurement of net rotatum deviation for an automatic door system as a function of time for a closing cycle of a door without any interference, i.e. without any collision.

[0029] Fig. 4b illustrates a representation of a measurement of the net rotatum deviation as a function of time for the same automatic door system as for the one in Fig. 4a, but this time a collision occurs.

[0030] DETAILED DESCRIPTION

[0031] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms.

[0032] The present invention is directed towards detecting a collision during operation of an automatic door system. An automatic door system is designed to open and close doors without manual intervention. Some examples of types of automatic door systems are sliding doors, swing doors, and revolving doors. Other automatic door systems may be considered such as folding doors, telescopic doors, hermetic doors, speed gates, garage doors, etc.

[0033] An automatic door system will be discussed in connection with Fig. 1. The automatic door system 100 comprises a door operator 120 and a door 110. The door operator 120 is configured to operate the door 110. In case of a sliding door, the door operator 120 is configured to operate a door leaf to slide in a support structure such that the door leaf slides from a closed state to an open state, or vice versa. In case of a swing door, the door operator 120 is configured to operate a door leaf being hinged ly connected to a door frame to pivot such that the door leaf swings from a closed state to an open state, or vice versa. In case of a revolving door, the door operator 120 is configured to operate a rotating drum with a plurality of door leaves.

[0034] The door operator 120 comprises an electric motor 122 and a door mechanism 124. The electric motor 122 drives the door mechanism 124. Typically, a rotational force of the electric motor 122 is transmitted to the door mechanism 124 via a gear assembly 123. Such transmission of rotational force of the electric motor 122 to the door mechanism 124 allows for controlled and smooth movement of the door 110. The door mechanism 124 typically comprises mechanical linkage that connects the door operator 120 to the door 110 itself. The mechanical linkage translates the rotational force of the electric motor 122 into a motion of the door 110. The mechanical linkage is typically attached to a top portion of the door 110. Regardless of the type of door 110, the door operator 120 is configured to instruct the electric motor 122 to operate on the door mechanism 124 to open the door 110. Further, the door operator 120 may also be configured to instruct the electric motor 122 to operate on the door mechanism 124 to close the door 110.

[0035] The automatic door system 100 typically further comprises an activation device 130. The activation device 130 is configured to initiate the operation of the door 110. Some common activation devices 130 include: Push buttons, motion sensors and access control systems. Push buttons may be located near the door, users can press a button to activate the door. Motion sensors are configured to detect motion within a defined range, a detection of motion triggering the door to open. Motion sensors may be based on various technologies such as infrared sensors or radar. Access control systems may be operated using e.g. swipe cards, key fobs, or other access control devices. In summary, the activation device 130 is configured to generate an initiation signal for initiating an operation on the door 110 upon the activation device 130 being actuated.

[0036] The door operator 120 further comprises control circuitry 160. The control circuitry 160 may include a processor 161, such as a central processing unit, CPU, a microcontroller, or a microprocessor. The processor 161 is configured to execute program code stored in a memory 170, in order to carry out functions and operations of the door operator 120. The memory 170 may be one or more of a buffer, a flash memory, a hard drive, a removable medium, a volatile memory, a non-volatile memory, a random access memory, RAM, or another suitable memory unit. In a typical arrangement, the memory may include a nonvolatile memory for long term data storage and a volatile memory that functions as system memory for the control circuitry 160. The memory 170 may exchange data with the processor over a data bus. Accompanying control lines and an address bus between the memory 170 and the processor also may be present. Functions and operations of the door operator 120 may be embodied in the form of executable logic routines (e.g., lines of code, software programs, etc.) that are stored on a non-transitory computer readable medium (e.g., the memory 170) and are executed by the control circuitry 160 (e.g., using the processor 161). Furthermore, the functions and operations of the door operator 120 may be a stand-alone software application or form a part of a software application that carries out additional tasks related to the door operator 120. The functions and operations may be considered a method that the door operator 120 is configured to carry out. Also, while the described functions and operations may be implemented in software, such functionality may as well be carried out via dedicated hardware or firmware, or some combination of hardware, firmware and / or software.

[0037] The control circuitry 160 is configured to receive signals, e.g. the initiation signal from the activation device 130. Based on a received initiation signal, the control circuitry 160 is configured to initiate an opening cycle for opening the door 110. During the opening cycle the electric motor 122 is instructed to operate on the opening mechanism 124 to open the door 110. The control circuitry 160 may also be configured to manage different settings for the door 110, such as door operation speed, opening width, and hold-open times.

[0038] The components of the automatic door system 100 are typically powered by electricity. This is governed by a power supply 150 of the automatic door system 100. The power supply 150 may form part of the door operator 120. The power supply 150 is typically connected to mains via an electrical system of the building in which the door 110 is arranged. Moreover, the automatic door system 100 may comprise backup batteries to ensure operation during a power outage.

[0039] The sequence of operation of the door operator 120 generally involves keeping the door 110 in a closed position and in response to a signal from the activation device 130 initiating an opening cycle. When a person or object interacts with the activation device 130, an initiation signal is generated by the activation device 130, the control circuitry 160 is acting on this initiation signal and triggers the electric motor 122 to operate on the opening mechanism 124 to open the door 110. In this disclosure this operation is referred to as an opening cycle. Upon the door 110 being in an open state, after a predetermined time (often referred to as a hold-open time), the control circuitry 160 instructs the electric motor 122 to operate the opening mechanism 124 to close the door 110. This will hereinafter be referred to as a closing cycle.

[0040] The control circuitry 160 further comprises an encoder 162. The encoder 162 is used to monitor and provide feedback on the position and movement of the door 110. Encoders are commonly employed in automatic door systems 100 to ensure precise control over the motion of the door 110 and to gather information about a current degree of opening of the door 110. The current degree of opening being a measure of how much, e.g. what percentage, the door has opened from point zero, 0%, being the door in the closed position, to the fully open state, 100%. As the door 110 opens or closes, the encoder 162 generates a position signal that corresponds to the door's position, i.e. its degree of opening. This information may be used for different purposes by the control circuitry 160. For example, the position signal from the encoder 162 allows the control circuitry 160 to accurately determine the door's position, i.e. degree of opening, at any given time. Moreover, the position signal from the encoder 162 allows the control circuitry 160 to determine a speed and acceleration of the door 110 during an opening cycle and / or closing cycle. Hence, the position information provided by the encoder 162 may be used for controlling the speed, acceleration and deceleration of the door 110 during its movement. The use of an encoder 162 creates a closed-loop system in which the control circuitry 160 continuously receives feedback about the position of the door 110 and may adjust the electric motor operation to maintain desired performance. The feedback from the encoder 162 further allows for customization of the door operator 120. Parameters such as opening and closing speed, hold-open times, and acceleration profiles can be precisely controlled based on the real-time information provided by the encoder 162.

[0041] However, as readily understood by the skilled person, kinematic signals (position, speed, acceleration, etc.) can be measured using other sensors such as incremental encoders, hall sensors or accelerometers, or they can be estimated using the electro-magnetic force generated by the rotating motor.

[0042] During an opening cycle and / or a closing cycle it is important to monitor so that the door 110 is not injuring a person and / or an object entering an operating region of the door 110. In other words, a possible or actual collision with an obstacle within the operating region of the door 110 is to be monitored. Historically this has been made using safety sensors. Such safety sensors are configured to detect whether the operating region for the door 110 is clear. In the case that an obstruction is detected in the operating region by the safety sensor during an opening cycle and / or closing cycle, a safety signal is generated and sent to the door operator 120. Based on such a safety signal, the control circuitry 160 instructs the electric motor 122 to stop operation on the opening mechanism 124. Hence, during both the opening cycle and the closing cycle the safety sensor 140 ensures that the door 110 will not hit an obstruction detected in the operating region for the door 110.

[0043] However, as discussed above in the background section, safety sensors are in many situations too sensitive resulting in unwanted interruptions of the operation of the automatic door system. For example, a revolving door often stops when too many people try to pass it in the same section of the revolving door, because one of them will come too close to a door leaf of the revolving door. According to another example, a swing door often stops opening if a user approaches it from the side in which they open, e.g., if the approach a swing door from the outside of the building when the swing door swings outwards.

[0044] The collision detection of the present invention is based on the law of conservation of momentum stipulating that the total momentum, p(t), in a closed system is constant. In the case of an automatic door system 100, the sum of all forces acting on the automatic door system 100 integrated over time minus the momentum of the automatic door system 100 should be constant. This can be expressed as: sgn(ro(t)) dt - J ■ (< >(t)) = const. where / (t) is a motor current of the electric motor 122, where c (t) is a speed of the door 110, where J is the moment of inertia of the door system, i.e. of the electric motor 122, the gear assembly 123, the opening mechanism 124 and the door 110, , where kMis a torque constant of the electrical motor 122 (i.e. / ( t) ■ kMis the torque exerted by the electrical motor 122), Fvis the viscous friction, and Fcis the Coulomb friction. The moment of inertia, J, of the door system may be automatically estimated by the control circuitry when commissioning the door system. The derivative of the equation (1) above, i.e. the net torque (p(t)), must be zero for the total momentum to be constant. That is:

[0045] ^(p( ) = O ■ kM— Fv■ to(t) — Fc■ sgn(to(t)) -J ~ (< (t)) = 0 L lz L lz

[0046] However, a measurement of the net torque can be non-zero due to measurement noise, inaccurate system modelling or external forces. Thus, a threshold is defined, accounting for such inaccuracies. In case of no, or very limited amount of external forces, monitoring a net torque deviation may be used for determining if the door 110 has collided with an obstacle. This is because when a collision occurs, the speed and the acceleration of the door 110 decrease. As a result, a speed control function of the control circuitry 160 reacts by increasing the current to the electric motor 122. This leads to an increase of every term of the torque equation during an opening cycle and to a decrease of every term of the torque equation during a closing cycle. The only exception is the term regarding the Coulomb friction, that is only affected if the direction of travel changes.

[0047] In the above expression the subscript [...expdenotes the expected value and the subscript [... ]co^ denotes the change in value caused by a collision. Tcou(t) denotes the torque equivalent of the collision force. The value that can be monitored is the net torque deviation, that also includes measurement noise and system modelling inaccuracies.

[0048] However, in the case that the automatic door system 100 is exposed to wind, the wind load will influence the automatic door system 100 by generating additional friction to the automatic door system 100. Accordingly, any wind load will induce additional friction and influence the monitoring of the net torque deviation.

[0049] By using the derivative of the net torque deviation, i.e. the net rotatum deviation, influence from wind, may be reduced. This because wind speed may be seen as static in comparison to dynamics of the automatic door system 100. That is, the wind speed may be regarded as constant during the course of a door opening. Treating the wind force on the automatic door system 100 as constant, the wind force term may be removed by taking the derivative of the net torque deviation, i.e. the net rotatum derivation. The wind force on the door leaf do change when the door opens / closes, because the attack area (i.e., the area of the door leaf that is exposed to wind) changes. This change, however, is slow enough that it does not affect the net rotatum deviation. Hence, by monitoring the net rotatum deviation, a collision detection that is negligibly affected by wind may be achieved.

[0050] The net rotatum deviation, i.e. the derivative of the net torque deviation, (p(t)), can be expressed according to: wherein the derivative of the signum function sgn(a>(t)) is zero, because it is constant during the opening cycle or during the closing cycle, respectively. If there is a change of the sign of the speed c (t) during the opening cycle or during the closing cycle (i.e., when the door reverses direction), the net rotatum deviation is not evaluated for the moment when the speed is zero.

[0051] In connection with Fig. 2a a representation of a measurement of the net rotatum deviation as a function of time is illustrated for an operation cycle of a door 110 without any interference, i.e. without any collision, to the automatic door system 100. The units on the vertical axis have been removed deliberately since only the relative proportions matter in the context of collision detection. The horizontal axis represents time, increasing from left to right. However, it has been removed to improve the readability of the chart. The graph illustrates one operation cycle that takes about five seconds. A speed reference, i.e. the speed at which the door 110 is set to be moved, is also included in Fig. 2a. A speed controlling function of the control circuitry 160 is configured to operate the door 110 based on the speed reference.

[0052] As can be seen, the measured net rotatum deviation is affected by measurement noise and modelling inaccuracies. Especially, noise from the measurement of the position signal and / or the acceleration signal of the door 110 used to determine the acceleration, (co ( t) ) , d2and the jerk, — (co ( t) ) , of the door 110 may be amplified taking derivative(s) of the position signal and / or the acceleration signal. The magnitude of net rotatum deviations strongly depends on the automatic door system 100 itself, but also on the accuracy of the parameter estimation and the speed controlling function. Therefore, a calibration procedure is preferably performed. During such a calibration procedure the automatic door system 100 learns the magnitude of the net rotatum deviations that occur during collision-free operation. During collision-free operation, the automatic door system 100 is operated according to the speed reference and the net rotatum deviation is measured as a function of time. Based thereon an extreme net rotatum deviation value of the automatic door system 100 can be determined. In Fig. 2a, the extreme net rotatum deviation value is a minimum net rotatum deviation, this since for the set-up showcased in connection with Fig. 2 a collision influencing the set-up will decrease the net rotatum deviation. However, it is readily understood that for other set-ups the net rotatum deviation value may instead increase if the set-up is affected by a collision and hence a maximum net rotatum deviation may be used. In Fig. 2a, the minimum net rotatum deviation value is illustrated as a dotted line. The extreme net rotatum deviation value may be determined as an average from a plurality of measured collision free operation cycles. A threshold for determining whether a collision has occurred may then be set based on the extreme net rotatum deviation value. The threshold is typically set as the extreme net rotatum deviation multiplied by a safety factor. The safety factor is a design variable being larger than one. A relatively small safety factor will increase the sensitivity for collision detection and a relatively large safety factor will reduce the risk of false detections. A threshold for collision detection is also illustrated in Fig. 2a as a dash-dotted line.

[0053] In Fig. 2b a representation of a measurement of the net rotatum deviation as a function of time for the same automatic door system 100 as for the one in Fig. 2a is illustrated, with the difference that Fig. 2b illustrates a situation in which a collision occurs. More precisely, a collision occurs during the constant speed phase. The collision is detected when the net rotatum deviation exceeds the threshold for collision. In connection with a detected collision, the control circuitry 160 may be configured to issue a collision signal.

[0054] Hence, in order to detect a collision during operation of the automatic door system 100 being exposed to wind, the control circuitry 160 may be configured to execute a monitoring function 172 and a collision detection function 174. The monitoring function 172 is configured to monitor the net rotatum deviation of the automatic door system 100 while the electric motor 122 is driving the door mechanism 124 for operating the door 110. The collision detection function 174 is configured to, when the net rotatum deviation exceeds a threshold for collision, issue a collision signal. The net rotatum deviation is monitored in accordance with the discussion above. Accordingly, monitoring the net rotatum deviation of the automatic door system 100 while the electric motor 122 is driving the door mechanism 124 for operating the door 110 may comprise to monitor the following:

[0055] • the motor current, / (t), of the electric motor 122; d d2

[0056] • the speed, r (t), the acceleration, — (c (t)) , and the jerk, — (co (t)) , of the door 110 based on a position signal and / or an acceleration signal of the door 110. Such position signal and / or acceleration signal(s) may be measured by the encoder 162 or other sensor(s) such as incremental encoders, hall sensors or accelerometers. Alternatively, they can be estimated using means such as the electro-magnetic force generated by the electric motor.

[0057] The net rotatum deviation, (p(t)), may then be determined according to: wherein kMis the torque constant for the electric motor, Fvis the viscous friction and J is the moment of inertia of the door system. Hence, it is the control circuitry 160 that is configured to monitor the derivative of the motor current, — Z(t), of the electric motor 122, dt d d2monitor the acceleration, — (co ( t)) , and the jerk, — (co ( t)) , of the door 110 and to calculate the net rotatum deviation.

[0058] The threshold for collision may be set by the control circuitry 160 executing a calibration function 171 configured to set the threshold for collision in accordance with calibration procedure discussed above. That is, the calibration function 171 is configured to set the threshold for collision by detecting an extreme net rotatum deviation of the automatic door system during a collision free operating cycle of automatic door system and determining the threshold for collision based on the extreme net rotatum deviation.

[0059] The control circuitry 160 may further be configured to, in response to the collision signal, execute a termination function 176. The termination function 176 is configured to terminate the operation of the automatic door system 100.

[0060] Alternatively, the control circuitry 160 may further be configured to, in response to the collision signal, execute a reversing function 178. The reversing function 178 is configured to reverse the driving of the electric motor 122.

[0061] Fig. 3 is a flow chart illustrating the steps of a method 300 for detecting a collision during operation of an automatic door system 100. Below, the different steps are described in more detail. Even though illustrated in a specific order, the steps of the method 300 may be performed in any suitable order, in parallel, as well as multiple times. Some of the steps, or even all steps, of the method 300 may be executed by the door operator 120 discussed above. However, at least some of the steps may be executed at another device.

[0062] The method may comprise setting S301 a threshold for collision. This may be made by detecting S301a an extreme net rotatum deviation of the automatic door system 100 during a collision free operating cycle of the automatic door system 100 and determining S301b the threshold for collision based on the detected extreme net rotatum deviation. Setting S301 the threshold for collision may further comprise, during the collision free operating cycle of the automatic door system 100, recording the net rotatum deviation of the automatic door system 100 while operating the door 110 to follow a predetermined speed reference over time.

[0063] The method comprises monitoring S302 a net rotatum deviation of the automatic door system 100 while operating a door 110 of the automatic door system 100, and upon the net rotatum deviation exceeding a threshold for collision, issuing S304 a collision signal. Just as when setting S301 the threshold for collision, the automatic door system 100 is here operated to follow the predetermined speed reference over time.

[0064] With reference to equation (3) above and the discussion about net rotatum deviation cZ2 / \ made in connection therewith, monitoring S302 the net rotatum deviation, — p(t)J, of the automatic door system 100 may comprise the following actions. Monitoring S302a the motor current, / (t), of an electric motor 122 of the automatic door system 100. Monitoring S302b d cZ2the speed, r (t), the acceleration, — (c (t)) , and the jerk, — (co (t)) , of the door 110 of the automatic door system 100. The monitoring of the speed, the acceleration and the jerk of the door 110 may be based on a position signal and / or an acceleration signal of the door 110. Such position signal and / or acceleration signal may be measured by the encoder 162 or other sensor(s) such as incremental encoders, hall sensors or accelerometers. Alternatively, they can be estimated using the electro-magnetic force generated by the electric motor or using other estimation algorithms. Based on the monitored parameters, the net rotatum deviation, d2 / \

[0065] — p(t)J, may be determined S302d according to: The method may further comprise, in response to the collision signal, terminating

[0066] S306a the operation of the automatic door system 100.

[0067] The method may further comprise, in response to the collision signal, reversing S306b the operation of the automatic door system 100 by reversing the driving of the electric motor 122.

[0068] As discussed above, an operating cycle (i.e. an opening cycle or a closing cycle) of the automatic door system 100 may comprise a plurality of operation phases. These operation phases may also be referred to as an acceleration phase, a constant speed phase and a deceleration phase. During the calibration procedure, a respective extreme net rotatum deviation for each such operation phase may be determined. Further, a respective threshold for collision for each such operation phase may be determined. This is illustrated in connection with Fig. 4a. As illustrated, extreme net rotatum deviations are evaluated for each operation phase individually and hence individual thresholds for collision may be set for the different operation phases. In Fig. 4b a representation of a measurement of the net rotatum deviation as a function of time for the same automatic door system 100 as for the one in Fig. 4a is illustrated, with the difference that Fig. 4b illustrates a situation in which a collision occurs. More precisely, a collision occurs during the constant speed phase. The collision is detected upon the net rotatum deviation exceeding the threshold for collision set in the constant speed phase. Again, in connection with a detected collision, the control circuitry 160 is configured to issue a collision signal.

[0069] The person skilled in the art realizes that the present invention by no means is limited to what is explicitly described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

[0070] Additionally, variations can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

Claims

CLAIMS1. A door operator (120) configured to operate a door (110) of an automatic door system (100), the door operator (120) comprising: a door mechanism (124) configured to operate on a door (110) of the automatic door system (100); an electric motor (122) configured to drive the door mechanism (124); and control circuitry (160) configured to execute: a monitoring function (172) configured to monitor a net rotatum deviation of the automatic door system (100) while the electric motor (122) is driving the door mechanism (124) for operating the door (110), and a collision detection function (174) configured to, upon the net rotatum deviation exceeding a threshold for collision, issue a collision signal.

2. The door operator (120) according claim 1, wherein to monitor the net rotatum deviation of the automatic door system (100) while the electric motor (122) is driving the door mechanism (124) for operating the door (110) comprises: monitor a motor current, / (t), of the electric motor (122), d d2monitor a speed, r (t), an acceleration, — (c (t)) , and a jerk, — (co (t)), of the door(110) based on a position signal and / or an acceleration signal of the door (110), anddetermine the net rotatum deviation (p(t)) according to:wherein kMis a torque constant for the electric motor, Fvis the viscous friction and J is the moment of inertia of the door system.

3. The door operator according claim 1 or 2, wherein the control circuitry (160) is further configured to execute a calibration function (171) configured to set the threshold for collision by: detecting an extreme net rotatum deviation of the automatic door system during a collision free operating cycle of the automatic door system; and determining the threshold for collision based on the extreme net rotatum deviation.

4. The door operator (120) according to claim 3, wherein an operating cycle of the automatic door system (100) comprises a plurality of operation phases, wherein the calibration function (171) is configured to detect an extreme net rotatum deviation for each such operation phase and determine a threshold for collision for each such operation phase.

5. The door operator (120) according to claim 3 or 4, wherein determining the threshold for collision further comprises, during the collision free operating cycle of the automatic door system (100), record the net rotatum deviation of the automatic door system (100) while operating the door (110) to follow a predetermined speed reference over time.

6. The door operator (120) according to any one of claims 1-5, wherein the control circuitry (160) is further configured to, in response to the collision signal, execute a termination function (176) configured to terminate the operation of the automatic door system (100).

7. The door operator (120) according to any one of claims 1-5, wherein the control circuitry (160) is further configured to, in response to the collision signal, execute a reversing function (178) configured to reverse the driving of the electric motor (122).

8. An automatic door system (100) comprising the door operator (120) according to any one of claims 1-7 and a door (110).

9. A method (300) for detecting a collision during operation of an automatic door system (100), the method comprising: monitoring (S302) a net rotatum deviation of the automatic door system (100) while operating a door (110) of the automatic door system (100); upon the net rotatum deviation exceeding a threshold for collision, issuing (S304) a collision signal.

10. The method (300) according to claim 9, wherein monitoring (S302) the net rotatum deviation,of the automatic door system (100) comprises:monitoring (S302a) a motor current, / (t), of an electric motor (122) of the automatic door system (100), d d2monitoring (S302b) a speed, r (t), an acceleration, — (c (t)) , and a jerk, — (c (t)),ofthe door (110) based on a position signal and / or an acceleration signal of the door (110), and determining (S302d) the net rotatum deviation, (p(t)), according to:wherein kMis a torque constant for the electric motor, Fvis the viscous friction and J is the moment of inertia of the door system.

11. The method (300) according to claim 9 or 10, further comprising setting (S301) the threshold for collision by: detecting (S301a) an extreme net rotatum deviation of the automatic door system (100) during a collision free operating cycle of the automatic door system (100); determining (S301b) the threshold for collision based on the detected extreme net rotatum deviation.

12. The method (300) according to claim 11, wherein an operating cycle of the automatic door system (100) comprises a plurality of operation phases, wherein an extreme net rotatum deviation is detected (S301a) for each such operation phase and wherein a threshold for collision is determined (S301b) for each such operation phase.

13. The method (300) according to claim 11 or 12, wherein setting (S301) the threshold for collision further comprises, during the collision free operating cycle of the automatic door system (100), recording the net rotatum deviation of the automatic door system (100) while operating the door (110) to follow a predetermined speed reference over time.

14. The method (300) according to any one of claims 9-13, further comprising, in response to the collision signal, terminating (S306a) the operation of the automatic door system (100).

15. The method (300) according to any one of claims 9-13, further comprising, in response to the collision signal, reversing (S306b) the operation of the automatic door system (100) by reversing the driving of the electric motor (122).

Images