Drive system for an actuator

Abstract

Drive system (1) for an actuator, comprising: an electric motor (2) for outputting torque for actuating the actuator, a first drive electronics unit (3) designed to provide electrical power to a motor terminal (4) for driving the electric motor (2), a second drive electronics unit (5) designed to provide electrical power to the motor terminal (4) for driving the electric motor (2), a first insulating device (6) provided in a connection between the first drive electronics unit (3) and the motor terminal (4) and which, in an active state, electrically isolates the first drive electronics unit (3) from the motor terminal (4), a second insulating device (7) provided in a connection between the second drive electronics unit (5) and the motor terminal (4) and which, in an active state, electrically isolates the second drive electronics unit (5) from the motor terminal (4).and a damping unit (8) which is connected to the electric motor (2) via the motor connection (4) and serves to increase the resistance of movement of the electric motor (2) when required, wherein the first drive electronics (3) and the second drive electronics (5) are redundant to each other, and the damping unit (8) is designed to detect the state of the first insulating device (6) and the state of the second insulating device (7) and to dampen the electric motor (2) when both insulating devices (6, 7) are in their active state.

Description

The present invention relates to a drive system for an actuator, in particular an electromechanical actuator.The drive system of an electromechanical actuator plays a decisive role in modern aviation technology, in particular in the primary flight control systems of aircraft. These actuators are responsible for the precise manipulation of the control elements such as flaps, rudders and other critical components. They replace conventional hydraulic systems with a more efficient, lighter and often more reliable electromechanical solution.A component of such a drive system is an electric motor which converts electrical energy directly into mechanical energy which then supplies the necessary movement and force via a transmission for actuating the control elements to be operated with the actuator.The implementation of redundant systems in critical components such as the propulsion systems of electromechanical actuators of an aircraft is an important aspect for ensuring the highest safety standards. For this reason, it is customary in aviation to make safety-critical actuators redundant.Various drives with redundant control electronics are already known from the publications DE 198 35 576 A1, DE 10 2020 206 478 A1, U.S. Pat. No. 2023 / 0 344 378 A1 and U.S. Pat. No. 2022 / 0 037 875 A1.Conventionally, such redundancy is achieved by completely duplicating an electric drive train, the parallel drive trains then running on a common transmission which is capable of decoupling a faulty drive train. It is disadvantageous here that a realization with two drive trains that are redundant to one another is very expensive and requires a large installation volume.It is further problematic that, in the case of a redundant implementation of the drive train, no precautions are taken for the case if an overall failure of the two drive trains should nevertheless occur, so that, for example in the case of an electromechanical actuator, the one flight control surface then actuates this has the result that the flight control surface can be set, on account of vibration or flow conditions acting from the outside, into a vibration state which can lead to massive damage to the flight control surface itself, but also to damage to adjacent structural components.It is the object of the present invention to provide a drive system which overcomes or at least alleviates the above-mentioned disadvantages. This is achieved with a drive system according to the subject matter of claim 1.The drive system according to the invention for an actuator, in particular an electromechanical actuator for use in an aircraft, comprises an electric motor for outputting a torque for actuating the actuator, a first drive electronics which is designed to provide electric power to a motor connection for driving the electric motor, a second drive electronics which is designed to provide electric power to the motor connection for driving the electric motor, a first insulation device which is provided in a connection between the first drive electronics and the motor connection and, in an active state, electrically isolates the first drive electronics from the motor connection, a second insulation device which is provided in a connection between the second drive electronics and the motor connection and, in an active state, electrically isolates the second drive electronics from the motor connection, and a damping unit, which is connected to the electric motor via the motor connection and serves to increase a resistance to movement of the electric motor if required, wherein the first drive electronics and the second drive electronics are redundant with respect to one another, and the damping unit is designed to detect the state of the first insulating device and the state of the second insulating device and to bring about damping of the electric motor when both insulating devices are in their active state.According to the invention, it is therefore provided that there are first drive electronics and second drive electronics which are designed to be redundant with respect to one another. The first drive electronics or the second drive electronics are designed to regulate the electric motor, so that the drive system is constructed redundantly with respect to the electric part of the drive train by duplication of the corresponding components. In addition to this redundant structure, a damping unit is also provided which dampens the movement of the electric motor when neither the first drive electronics nor the second drive electronics are able to control or regulate the motor via a corresponding electrical power output to the motor connection. The damping unit is equipped with sensors which check the active or inactive state of a respective insulating device assigned to drive electronics. If both the first insulating device which is assigned to the first drive electronics and the second insulating device which is assigned to the second drive electronics are in an active state, that is to say if both drive electronics are electrically insulated with respect to the motor connection and therefore cannot regulate the motor, the damping unit brings about damping of the electric motor in order to prevent oscillations of the element to be controlled by the actuator.It is advantageous here that the drive system according to the invention also considers the case when both redundant drive electronics are no longer capable of regulating the electric motor. In this case, the damping unit takes over and ensures damping of the electric motor, so that oscillations of the element actuated by the actuator are suppressed.According to an optional development of the present invention, the first insulating device and the second insulating device can each be implemented by a switch which interrupts the electrical connection between the associated drive electronics and the motor connection of the electric motor if required. This ensures that, if a drive unit outputs faulty signals for regulating the electric motor, they are no longer transmitted to the motor connection.In addition, the provision of the insulating device is advantageous since the drive electronics which are not in operation and which are used only in the event of a fault in the drive electronics which are in operation are also protected from possible feedbacks of the first drive electronics or of the motor connection by means of the insulating device. Finally, the insulating device of the drive electronics not used for operating the motor is likewise electrically isolated or insulated from the motor connection by means of a switch or the like.According to an advantageous modification of the present invention, it can therefore be provided that the first insulating device and the second insulating device are designed such that at least one of the first drive electronics and the second drive electronics is electrically insulated from the motor connection. As already explained above, the implementation of the electrical insulation device by a switch can be considered advantageous.According to a further optional development of the present invention, it can be provided that the first drive electronics and the second drive electronics are each designed to switch between an active mode for regulating the electric motor and a control mode for monitoring the drive system, in particular the electric motor and / or the other drive electronics, wherein the control mode serves to monitor a fault-free state.One of the two drive electronics is advantageously in an active mode and the other of the two drive electronics is in a control mode, so that it is not the case that both drive electronics send signals to the electric motor simultaneously. At least one of the two drive electronics is electrically insulated from the electric motor by means of the two insulating devices, so that it is not possible to transmit control signals simultaneously to the motor connection.In this case, it can advantageously be provided that the first drive electronics and the second drive electronics are each designed in the control mode to activate the insulating device of the other drive electronics when a faulty state is detected, and to switch to the active mode in order to take over the regulation of the electric motor.In a control mode, although the drive electronics system in the control mode are electrically isolated from the electric motor by an active state of the insulating device, each of the two drive electronics systems receives the same input signals, regardless of which mode the drive electronics system is in, so that a drive electronics system in the control mode can monitor the drive electronics system in the active mode. For this purpose, it is compared, for example, which signals the drive electronics system in the active mode output and checks whether this corresponds to the signals that the drive electronics system in the control mode would have output on the basis of the input signals received. If there is a deviation in this regard, the drive electronics which are in the control mode can attempt to change to the active mode, wherein firstly the insulating device of the drive electronics which are considered to be faulty is placed in the active state and the insulating device of the drive electronics which are still in the control mode is deactivated, with the result that the previously electrically insulated drive electronics are now connected to the motor connection of the electric motor. If a drive electronics system in the control mode has thus detected a fault in the drive electronics system in the active mode, a mode change of the drive electronics system in the control mode can be carried out, which at the same time has the effect that the drive electronics system considered to be faulty is pulled off from the control system of the electric motor by transferring the insulating device into the active state.According to a further optional modification of the present invention, it can be provided that the first drive electronics and the second drive electronics in the active mode are each designed to monitor themselves and to activate the associated insulating device when a faulty state is detected.Advantageously, in the case of a self-detected fault state of a drive electronics system, a signal can also be sent to the other drive electronics system in order to take over the regulation of the electric motor, so that the drive electronics system which is actually in the control mode takes over the control of the motor. If, however, the other drive electronics also has detected a fault by themselves or if a fault was detected by a superordinate control entity, it is possible that the other drive electronics do not follow this request, so that the state occurs in which both drive electronics are electrically separated from the motor by their associated insulating device, so that no electrical power is supplied to the motor. Such a state is detected by the damping unit, which then brings about damping of the electric motor. Thus, provision is also made for the case in which both drive electronics, which are embodied redundantly with respect to one another, fail or assume a state which is not completely free of faults, but an unattenuated state of an electromechanical actuator provided with the drive system according to the invention nevertheless does not occur, since the electric motor which drives the actuator is attenuated by the attenuation unit.According to an advantageous development of the present invention, it can be provided that the first drive unit and the second drive unit are linked to identical input signals for driving the electric motor, which input signals are used in a control mode to monitor the other drive unit located in the active mode, in particular by adjusting a motor rotational speed, and / or a current value and / or voltage value supplied by the other drive unit to the motor connection.The drive electronics stored on account of the redundant design are therefore also supplied with the input signals for driving the drive electronics if an output of the signals to the electric motor is actually not provided, since the other drive electronics take over this. This has the background that the supply of the input signals to the redundantly stored drive electronics is used to monitor the other drive electronics. In this case, the input signals are thus processed as if the redundantly stored drive electronics were actually connected to the electric motor, so that a comparison can be made as to whether the control signals for the motor generated by the redundantly stored drive electronics deviate from the control signals of the other drive electronics. If this is the case, the redundantly stored drive electronics can leave the control mode and switch to the active mode, wherein the other drive electronics are disconnected from a connection with the electric motor by the transfer of the associated insulating device (by signaling from the other drive electronics) into the active state.According to a further optional development of the present invention, it can be provided that, in a fault-free state of the drive system, one drive electronics is in the active mode and the other drive electronics is in the control mode. This corresponds to a normal state of the drive system according to the invention, since one of the two drive electronics actually generates the signals which are supplied to the electric motor, and the other drive electronics is stored redundantly and their connection to the motor connection of the electric motor is interrupted by means of the insulating device.According to an advantageous embodiment of the present invention, it can be provided that the motor connection comprises a plurality of lines which are connected to a respective phase of the electric motor.Typically, each of the two drive electronics is configured to output a specific power signal for each phase of the motor, preferably one having a specific current value and a specific voltage value.Advantageously, according to the invention, it can be provided that the electric motor is a permanent magnet synchronous motor or a brushless direct current motor. The commutation of the electric motor corresponds to a standard commutation.According to a further advantageous modification of the present invention, it can be provided that the damping unit is designed to short-circuit the phases of the motor in order to generate a resistance against a rotational movement of the motor. This causes simple implementation of damping during the movement of the motor.Furthermore, according to an advantageous development of the present invention, it can be provided that the damping unit is designed to switch the phases of the motor to an electrical or electronic load in order to generate a resistance against a rotational movement of the motor. This also makes damping easy to implement in the movement of the motor.Furthermore, according to an advantageous modification of the present invention, it can be provided that the damping unit is integrated in the electric motor.The invention also relates to an electromechanical actuator having a drive system according to one of the aspects discussed above.According to an optional development of the present invention, it can be provided that the actuator is designed for use in a primary flight control of an aircraft. Thus, the actuator can serve, for example, for actuating an air guide surface of an aircraft, so that the advantages of the drive system according to the invention exhibit particular effect here.In addition, the present invention relates to an aircraft having an electromechanical actuator according to one of the aspects discussed above.Further features, details and advantages of the invention will become apparent from the following description of the figures. The following shows: FIG. 1 : shows a schematic illustration of a drive system according to the invention for an actuator.FIG. 1 shows a schematic illustration of the drive system 1 according to the invention.The electric motor 2 is shown, which serves to actuate an actuator. Furthermore, a first electronic drive unit 3 and a second electronic drive unit 5 are provided, each of which is designed to be redundant with respect to one another. Each of the two drive electronics 3, 5 is actuated via input signals (not shown), which sense the position of a controller, for example, in order to effect a control of the actuator connected to the electric motor 2 corresponding to the controller position.For this purpose, each of the two drive electronics 3, 5 is connected to a motor connection 4 of the electric motor 2. In order to keep the number of lines low, the electric motor connection 4 is present only once and can receive corresponding signals for regulating the electric motor 2 from each of the two drive electronics 3, 5. Accordingly, a signal for driving the electric motor 2 is sent from the first drive electronics 3 via a line 10, which is connected to a line 9, which is used for driving the electric motor 2 from the second drive electronics 5.However, in order that the electric motor 2 is not driven divergingly or twice via the motor connection 4, an insulating device 6, 7 is provided in each of the lines 9, 10, which insulating device is designed to electrically insulate the associated drive electronics 3, 5. This can be implemented, for example, by the provision of a switch which is transferred into its open position, so that the associated drive electronics 3, 5 are isolated.In the regulating mode, one of the two drive electronics 3, 5 is responsible for regulating the electric motor 2, with the result that corresponding drive signals must be transmitted to the motor connection 4 of the electric motor 2 by the drive electronics 3, 5 responsible for regulating the electric motor 2. It is thus provided that one of the two insulating devices 6, 7 is in its inactive state, which allows signals output by an associated drive electronics 3, 5 to be conducted to the motor connection 4.The other drive electronics 3, 5, whose associated insulating device 6, 7 is in their active state, therefore cannot act on the electric motor 2, since the signals actually intended for conducting to the motor connection 4 are not passed on because of the insulating device and the electrical insulation thus effected.Furthermore, the damping unit provided with the reference numeral 8 can be seen, which is likewise connected to the motor connection 4 of the electric motor 2. If required, this can short-circuit the different phases of the electric motor 2 to one another or connect these to one another via an electrical or an electronic load, which brings about damping of the electric motor 2.The damping unit is designed to detect the state of the two insulating devices 6, 7 and to effect damping of the electric motor 2 as a function thereof. Damping of the motor 2 is only carried out when the state is detected that both insulating devices 6, 7 are in their active state, which means that neither the first drive electronics 3 nor the second drive electronics 5 have an electrical connection to the motor connection 4 of the motor 2, that is to say that the motor 2 receives no control signals. In order to prevent unwanted oscillations from occurring due to external influences, for example an air flow on an air guiding element of an electromechanical actuator which is provided with the drive system according to the invention, which oscillations can cause damage to components of the drive system or even adjacent components in the incorporated structure of the drive system, the damper unit has a damping effect on the motor 2.Furthermore, the lines 11, 12 are visible, which run from one drive electronics 3, 5 to the insulating device 6, 7 of the other drive electronics 3, 5. Since it is clear that both drive electronics 3, 5 cannot send control signals simultaneously to a motor connection 4 of the motor 2, there is one drive electronics 3, 5 which is in an active state and another drive electronics 3, 5 which is in a so-called control mode.In this control mode, the drive electronics 3, 5 are electrically insulated from the motor connection 4 with the aid of the associated insulating device 6, 7, so that any outputs of the drive electronics 3, 5 are not passed on at the motor connection 4. Each of the two drive electronics 3, 5, however, is capable of monitoring the drive system in the control mode, in particular the drive electronics 3, 5 located in the active mode, of monitoring the electric motor 2 or its parameters, such as rotational speed, torques or the like, or also the drive signals output by the drive electronics 3, 5 located in the active state.If the drive electronics 3, 5 in the control mode represent a deviation from the values that they are considered correct, the drive electronics 3, 5 in the control mode can attempt to change to the active mode and at the same time draw the drive electronics 3, 5 previously in the active mode from the control of the electric motor 2. This is achieved in that the drive electronics 3, 5 located in the control mode activates the insulating device 6, 7 of the other drive electronics 3, 5 and deactivates the other insulating device 6, 7, so that the drive electronics 3, 5 previously located in the control mode can now take over a control of the motor 2.If, on the other hand, faults are detected in both drive electronics 3, 5, either by themselves, a superordinate control entity and / or the other drive electronics 3, 5, none of the two drive electronics 3, 5 is available for controlling the electric motor 2, so that the damping unit 8 detects an active state of the two insulation devices 6, 7 and brings about damping of the motor 2.List of reference numbers:1 Drive system 2 Electric motor 3 First drive electronics 4 Motor connection 5 Second drive electronics 6 First insulating device 7 Second insulating device 8 Damping unit 9 Line(s) for driving the motor of the second drive electronics 10 Line(s) for driving the motor of the first drive electronics 11 Line of the second drive electronics for activating the first insulating device 12 Line of the first drive electronics for activating the second insulating device

Claims

A drive system (1) for an actuator, comprising: an electric motor (2) for outputting a torque for actuating the actuator; first drive electronics (3) configured to provide electric power to a motor terminal (4) for driving the electric motor (2); second drive electronics (5) configured to provide electric power to the motor terminal (4) for driving the electric motor (2); a first isolation device (6) provided in a connection between the first drive electronics (3) and the motor terminal (4) and in an active state electrically isolating the first drive electronics (3) from the motor terminal (4); a second isolation device (7), which is provided in a connection between the second drive electronics (5) and the motor connection (4) and electrically isolates the second drive electronics (5) from the motor connection (4) in an active state, and a damping unit (8) which is connected to the electric motor (2) via the motor connection (4) and serves to increase a movement resistance of the electric motor (2) if required, wherein the first drive electronics (3) and the second drive electronics (5) are redundant with respect to one another, and the damping unit (8) is designed to detect the state of the first insulating device (6) and the state of the second insulating device (7) and to effect damping of the electric motor (2) when both insulating devices (6, 7) are in their active state.The drive system (1) according to the preceding claim 1, wherein the first insulating device (6) and the second insulating device (7) are configured such that at least one of the first drive electronics (3) and the second drive electronics (5) is electrically insulated from the motor terminal (4).Drive system (1) according to one of the preceding claims, wherein the first drive electronics (3) and the second drive electronics (5) are each designed to switch between an active mode for regulating the electric motor (2) and a control mode for monitoring the drive system (1), in particular the electric motor (2) and / or the other drive electronics (3, 5), wherein the control mode serves to monitor a fault-free state.Drive system (1) according to the preceding claim 3, wherein the first drive electronics (3) and the second drive electronics (5) are each designed, in the monitoring mode, to activate the insulating device (6, 7) of the other drive electronics (3, 5) upon detection of a faulty state, and to switch to the active mode in order to take over the regulation of the electric motor (2).Drive system (1) according to one of the preceding claims 3 or 4, wherein the first drive electronics (3) and the second drive electronics (5) in the active mode are each designed to monitor themselves and to activate the associated insulation device (6, 7) when a faulty state is detected.Drive system (1) according to one of the preceding claims, wherein the first drive unit and the second drive unit are linked to identical input signals for driving the electric motor (2), which are used in a control mode to monitor the other drive unit located in the active mode, in particular by adjusting a motor rotational speed, and / or a current value and / or voltage value supplied by the other drive unit to the motor connection (4).Drive system (1) according to one of the preceding claims, wherein in a fault-free state of the drive system (1), one drive electronics (3, 5) is in the active mode and the other drive electronics (3, 5) is in the control mode.The drive system (1) according to any one of the preceding claims, wherein the motor terminal (4) comprises a plurality of leads connected to a respective phase of the electric motor (2).The drive system (1) according to any one of the preceding claims, wherein the electric motor (2) is a permanent magnet synchronous motor or a brushless DC motor.The drive system (1) according to any one of the preceding claims, wherein the damping unit (8) is configured to short-circuit the phases of the motor (2) to generate a resistance against a rotational movement of the motor (2).Drive system (1) according to one of the preceding claims, wherein the damping unit (8) is configured to switch the phases of the motor (2) to an electrical or electronic load in order to generate a resistance against a rotational movement of the motor (2).Drive system (1) according to one of the preceding claims, wherein the damping unit (8) is integrated in the electric motor (2).Electromechanical actuator having a drive system (1) according to one of the preceding claims.The electromechanical actuator of claim 13, wherein the actuator is configured for use in a primary flight control of an aircraft.Aircraft with an electromechanical actuator according to one of the preceding claims 13 or 14.

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