Method for decelerating servo motor of steering device

Abstract

To decelerate a servo motor of a steering device for protection especially maintenance operation situations.SOLUTION: A steering device comprises: a control unit (12a) which controls drive of a servo motor (10a); a monitoring electronic circuit (14a) which monitors movement of the servo motor; and an energy storage unit (18a) which is operably connected to the control unit and the monitoring electronic circuit, and is so configured as to be different from a vehicle battery (16a). By evaluating a motion characteristic amount correlated to movement of the servo motor using the monitoring electronic circuit, movement of the servo motor, which is caused by external force, is monitored, and a deceleration process for decelerating the servo motor using the control unit is triggered depending on the motion characteristic amount. The energy storage unit is charged by movement of the servo motor, and in at least one application case, is used for energy supply to the control unit and the monitoring electronic circuit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] Prior Art The present invention relates to a method for decelerating a servomotor of a steering device and to a corresponding steering device, and also to a vehicle equipped with such a steering device. [Background technology]

[0002] During maintenance and / or repair work in a car workshop, the wheels of a vehicle may be manually accelerated, and the energy generated by this acceleration and / or stored in the steering system of the vehicle is immediately and suddenly reduced at the mechanical end stops or, in steering systems without end stops, at the transmission side module of the steering system, which may cause damage to the steering system. What is even more difficult in this case is that during such maintenance and / or repair work, the ignition and / or operating switch of the vehicle is usually switched off, so that the control units and / or control devices of the vehicle are transferred to a special rest and / or ready state in order to reduce energy consumption, and therefore the acceleration of the wheels caused by external forces is not recognized by the control units and / or control devices themselves or is recognized very late.

[0003] For this reason, for example, in DE 10 2017 218 830 A1, a method for slowing down a servomotor of a steering device is proposed, in which the steering device comprises a control unit for controlling the servomotor and a monitoring electronic circuit for monitoring the motion of the servomotor, the monitoring electronic circuit being used to monitor the motion of the servomotor caused by external forces by evaluating a motion characteristic quantity that correlates with the motion of the servomotor, and in at least one operating state, a deceleration process for slowing down the servomotor is triggered by the control unit as a function of said motion characteristic quantity. It is also possible to use a voltage generated by the motion of the servomotor and / or an energy accumulator that is configured differently from the vehicle battery to supply energy to the monitoring electronic circuit. However, in this case, the voltage generated by the motion of the servomotor or the energy accumulator is only used to provide a short-term energy supply to the monitoring electronic circuit and is therefore not used at least for the energy supply to the control unit or for the energy supply to the control unit and the monitoring electronic circuit, so that, for example, in the case of a disconnection of the vehicle battery, an effective deceleration of the servomotor cannot be achieved by means of the voltage or energy accumulator mentioned above. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] DE 102017218830 Summary of the Invention [Problem to be solved by the invention]

[0005] Starting from this, the object of the present invention is to provide a method for decelerating a servomotor of a steering device, in particular a steering device having improved properties with regard to its mode of operation. This object is achieved by the features of claims 1, 8 and 9, preferred configurations and developments of the invention being taken from the respective dependent claims. [Means for solving the problem]

[0006] Disclosure of the Invention A method for slowing down a servo motor of a steering device, in particular for protection in maintenance operating situations, is proposed, the steering device comprising a control unit for driving and controlling the servo motor, a monitoring electronic circuit for monitoring the movement of the servo motor, and an energy accumulator operatively connected to the control unit and to the monitoring electronic circuit and configured to be different from the vehicle battery, the monitoring electronic circuit being used to monitor the movement of the servo motor caused by external forces by evaluating a movement characteristic quantity correlated with the movement of the servo motor, and in at least one operating state a deceleration process for slowing down the servo motor, in particular a deceleration process for braking the servo motor, preferably a deceleration process for completely stopping the movement of the servo motor, is triggered by the control unit in dependence on said movement characteristic quantities, and the energy accumulator is charged by the movement of the servo motor, in particular by a voltage and / or current generated by the movement of the servo motor, and in at least one application case is used to supply energy to the control unit and the monitoring electronic circuit. The energy accumulator can be used here, for example, to supply energy to the control unit and the monitoring electronics in case of interruption of the energy supply by the vehicle battery, for example when the vehicle battery is disconnected, or in case of faults, for example due to faults and / or failures of the vehicle battery and / or peripheral devices connected to the vehicle battery. Such an arrangement can in particular improve the operating method. Advantageously, an effective deceleration of the servo motor can also be achieved when the vehicle battery is disconnected. Furthermore, an effective and efficient protection of the mechanics and electronics of the steering system can be achieved, in particular in maintenance operating situations, and in particular also in vehicles and / or steering systems that are not provided with end stop dampers.

[0007] The steering device here is in particular configured to perform a method for decelerating a servo motor. "Configured" is to be understood in particular as being specially programmed, designed and / or equipped. An object being configured to perform a particular function is to be understood as the object fulfilling and / or executing the particular function in at least one application and / or operating state.

[0008] It is further proposed that, in terms of circuit technology, the energy accumulator is arranged in an intermediate circuit between the vehicle battery and the output electronics of the steering device, which makes it possible to achieve a particularly simple construction, in particular in which the energy accumulator is charged by the movement of the servo motor.

[0009] According to a particularly preferred configuration, it is proposed to use an intermediate circuit capacitance, i.e. in particular an existing capacitance of the steering device, which is also used in normal operating conditions, as the energy accumulator. In this case, in particular, the intermediate circuit capacitance can comprise a single or multiple intermediate circuit capacitors. In the latter case, multiple intermediate circuit capacitors cooperate as the energy accumulator. This in particular results in a very cost-effective solution.

[0010] According to an alternative configuration, it is proposed to arrange the energy accumulator in parallel with the intermediate circuit capacitance, i.e. the existing capacitance of the steering device, which is used in particular also in normal operating conditions, and to switch it on in the abovementioned application cases via a switching unit, in particular in the form of a transistor. Advantageously, in this case, the energy accumulator is configured as a capacitor. This results in particular in a very flexible and / or adaptive solution.

[0011] The intermediate circuit capacitance and the energy accumulator can be configured together for the energy supply of the control unit and the monitoring electronics in certain applications. However, it is preferably proposed to decouple the intermediate circuit capacitance from the intermediate circuit in certain applications. In this case, the decoupling can be achieved, for example, via the above-mentioned switching unit, in particular by switching between the intermediate circuit capacitance and the energy accumulator, or via another switching unit, preferably in the form of a transistor, which is configured differently from the above-mentioned switching unit. This makes it possible to avoid, in particular, possible interference effects.

[0012] Here, the method for decelerating a servo motor, the steering device, and the vehicle should not be limited to the above-mentioned applications and embodiments. In particular, the method for decelerating a servo motor, the steering device, and the vehicle may have a number of elements, parts, and units different from the number of individual elements, parts, and units mentioned in this specification in order to fulfill the functions described in this specification.

[0013] drawing Further advantages will become apparent from the following description of the drawings, in which an embodiment of the invention is shown. [Brief description of the drawings]

[0014] [Figure 1a] 1 is a schematic diagram illustrating an example vehicle equipped with a steering system including a steering device. [Figure 1b] 1 is a schematic diagram illustrating an example vehicle equipped with a steering system including a steering device. [Diagram 2] FIG. 2 is a schematic diagram showing a part of a steering device. [Diagram 3] 2 is a flow chart showing an example of a method for decelerating a servo motor of a steering device including the main method steps. [Figure 4] FIG. 4 is a schematic diagram showing another embodiment of a steering device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Description of the embodiment 1a and 1b show a schematic diagram of a vehicle 26a configured as an automobile with a number of wheels 28a and a steering system 30a, which is operatively connected to the wheels 28a and configured to control the direction of travel of the vehicle 26a. In the present embodiment, the steering system 30a is further configured as an electrically assisted steering system and has an electric steering device in the form of a power steering section. In principle, however, it is also conceivable that the steering system is configured as a hydraulically assisted steering system. The steering system can also be configured as a steer-by-wire steering system.

[0016] The steering system 30a comprises a steering arrangement which, with the exception of the energy accumulator 18a and / or the corresponding connection of the energy accumulator 18a, is substantially identical to the steering arrangement disclosed in DE 10 2017218830 A1, to which explicit reference is also made.

[0017] The steering device comprises a steering wheel 32a for applying a manual steering torque, a steering gear 34a, for example configured as a rack-and-pinion steering gear, which is configured in particular to convert the steering settings at the steering wheel 32a into a steering movement of the wheels 28a, which in this case are configured in particular as the front wheels, and a steering column 36a, which in particular mechanically connects the steering wheel 32a to the steering gear 34a. Alternatively, the steering wheel can be configured as a steering lever and / or a steering ball or the like. It is also conceivable to omit the steering wheel entirely. Furthermore, the steering column may only temporarily connect the steering wheel to the steering gear and / or have a mechanical decoupling, for example in a steer-by-wire steering system.

[0018] Furthermore, the steering arrangement comprises an assistance unit 38a, which is in particular electrically configured, which is provided for introducing a steering torque, in this case in particular in the form of an assistance torque, into the steering gear 34a. For this purpose, the assistance unit 38a comprises a servomotor 10a, which in this example is in particular configured as an electric motor. The servomotor 10a is configured as a polyphase electric motor, in this example for example as a three-phase electric motor. Alternatively, the servomotor may be part of a steering actuator, for example in the case where the steering system is configured as a steer-by-wire steering system.

[0019] The steering device further comprises a movement detection unit 40a, here for example in the form of a rotor position sensor. The movement detection unit 40a is arranged in the region of the servo motor 10a and is arranged to detect the movement of the servo motor 10a in a particularly contact-free manner. Furthermore, the movement detection unit 40a is arranged to detect a detection signal which correlates with the movement of the servo motor 10a and to supply it as a movement characteristic quantity.

[0020] The steering device further includes a control device 42a, which is operatively connected to the motion detection unit 40a and the assistance unit 38a. The control device 42a is configured to receive the motion characteristic quantity from the motion detection unit 40a. In addition, the control device 42a is configured to perform a drive control of the servo motor 10a.

[0021] For this purpose, the control device 42a comprises a control unit 12a (see FIG. 2) known per se. The control unit 12a comprises at least one processor (not shown), for example in the form of a microprocessor, and at least one operating memory (not shown). The control unit 12a also has at least two different operating modes, in particular a normal operating mode and a deceleration operating mode, in this embodiment. The control unit 12a is arranged to drive and control the servo motor 10a. In this embodiment, the control unit 12a is arranged to set an assist torque in the normal operating mode and to decelerate, preferably brake, the servo motor 10a in the deceleration operating mode. However, the control unit can alternatively also be arranged in the vehicle central control device.

[0022] Furthermore, the control device 42a has output electronics 22a, known per se, for example in the form of an output stage (see FIG. 2). The output electronics 22a is operatively connected to the control unit 12a and is downstream of the control unit 12a in terms of control technology. The output electronics 22a is also operatively connected to the servo motor 10a. The output electronics 22a is designed to operate the servo motor 10a in a manner known per se. In principle, however, the output electronics can be designed separately and / or separated from the control device.

[0023] Furthermore, the control unit 42a includes a monitoring electronic circuit 14a (see FIG. 2), which is in particular configured separately from the control unit 12a. The monitoring electronic circuit 14a is configured as an application specific integrated circuit (ASIC). The monitoring electronic circuit 14a is operatively connected to the motion detection unit 40a and to the control unit 12a and is configured to receive and continuously evaluate motion characteristic quantities from the motion detection unit 40a and thus to monitor the motion of the servo motor 10a. Alternatively, the monitoring electronic circuit can be integrated into the control unit, in which embodiment the monitoring electronic circuit is advantageously configured as a separate logic unit. It is also conceivable to arrange the monitoring electronic circuit in the vehicle central control unit.

[0024] For the energy supply of the steering system, i.e. in particular the control unit 12a, the monitoring electronics 14a and the output electronics 22a, the steering system further comprises a vehicle battery 16a, which here is arranged, at least in normal operating conditions, to supply the steering system with energy, in particular to supply the control unit 12a, the monitoring electronics 14a and the output electronics 22a with energy.

[0025] For further details regarding the design of the steering system, and in particular the design of the control device 42a, reference is made to DE 10 2017 218 830 A1, the disclosure content of which is expressly incorporated herein.

[0026] Here, in certain situations, for example during maintenance work and / or repairs, it may be provided that the wheels 28a of the vehicle 26a are manually accelerated and that such a movement is transmitted to the steering gear 34a and the servo motor 10a. Such situations are particularly critical in situations where the control unit 12a and / or further components of the steering device are at least partially inactive and / or in a stationary mode, in particular for energy saving. In particular, if the vehicle battery 16a is disconnected, the servo motor 10a cannot be correspondingly decelerated by the methods known from the prior art, which may cause damage, in particular in steering devices without end stop dampers.

[0027] For this reason, the steering system in the present embodiment includes, inter alia, an additional energy accumulator 18a. The energy accumulator 18a is different from the vehicle battery 16a. The energy accumulator 18a has an electrical connection with the output electronics 22a and thus with the servo motor 10a. In this case, in terms of circuit technology, the energy accumulator 18a is arranged in an intermediate circuit 20a between the vehicle battery 16a and the output electronics 22a. The energy accumulator 18a also has an electrical connection with the control unit 12a and the monitoring electronics 14a. Furthermore, the energy accumulator 18a is configured as a capacitor. In the present embodiment, the energy accumulator 18a corresponds to an intermediate circuit capacitance 24a of the steering system, i.e. corresponds to an existing capacitance that is used in particular also in normal operating conditions. However, as an alternative, the energy accumulator can also be configured separately from the intermediate circuit capacitance. It is also conceivable to configure the energy accumulator as a buffer battery or the like.

[0028] The energy accumulator 18a is configured to supply energy to the control unit 12a and the monitoring electronics 14a in at least one application case. In this embodiment, the energy accumulator 18a is configured to supply energy to at least the control unit 12a and the monitoring electronics 14a when the energy supply by the at least one vehicle battery 16a is interrupted or impaired, for example in maintenance operation situations and when the vehicle battery 16a is disconnected.

[0029] For this reason, the energy accumulator 18a is arranged and configured in such a way that it can be charged even in the event of disconnection of the vehicle battery 16a and / or in the event of a fault in the vehicle battery 16a. In this embodiment, the energy accumulator 18a is charged directly by the movement of the servo motor 10a, in particular by the voltage generated by said movement and / or by the current generated by said movement. This advantageously allows an effective deceleration of the servo motor 10a to be achieved even in the event of disconnection of the vehicle battery 16a. Furthermore, an effective and efficient protection can be achieved in maintenance driving situations, in particular also in steering devices that do not have end stop dampers.

[0030] FIG. 3 shows an exemplary flowchart illustrating the main method steps of a method for slowing down a corresponding servo motor 10a, in particular in cases where the energy supply by at least one vehicle battery 16a is interrupted, for example when the vehicle battery 16a is disconnected or when a fault occurs, for example due to a fault and / or defect in the vehicle battery 16a and / or peripheral devices connected to the vehicle battery 16a.

[0031] In method step 50a, a movement of the servo motor 10a is effected which is caused by an external force, for example a manual movement of the wheel 28a in a maintenance operation situation.

[0032] In method step 52a, the energy store 18a is charged by the motion of the servo motor 10a, in particular by the voltage generated by this motion and / or the current generated by this motion, when the energy or the voltage and / or the current of the energy store 18a reaches a corresponding limit value, which is sufficient to power the monitoring electronics 14a, after which the activation of the monitoring electronics 14a for monitoring the motion characteristic variable takes place.

[0033] In method step 54a, the monitoring electronics 14a check whether the movement characteristic quantity exceeds or falls below a threshold value. If the movement characteristic quantity exceeds the threshold value, method step 56a follows.

[0034] In method step 56a, the monitoring electronics 14a triggers a deceleration process by the control unit 12a, in particular by starting up and / or waking up, so that a transition to a deceleration operating mode is made. The control unit 12a is then configured to cause a deceleration, in particular an active or passive deceleration, of the servo motor 10a by the drive control by the output electronics 22a. The energy supply to the control unit 12a and to the output electronics 22a is likewise performed in this case by the energy store 18a.

[0035] In method step 58a, the control unit 12a and / or the monitoring electronics 14a check whether the movement characteristic quantity exceeds or falls below a further threshold value. If the movement characteristic quantity exceeds the further threshold value, a further method step 56a is carried out. If, on the other hand, the movement characteristic quantity falls below the further threshold value, a further method step 60a is carried out. In principle, the further threshold value may be identical to the above-mentioned threshold value.

[0036] In method step 60a, the deceleration process is ended. Subsequently, the control unit 12a returns again to a stationary state depending on the motion parameters and / or the activation duration.

[0037] For further details regarding how to decelerate the servo motor 10a, reference is likewise made to DE 102017218830 A1, the disclosure content of which is expressly incorporated herein.

[0038] However, the example flow chart of Fig. 3 is merely intended to exemplarily illustrate a method for decelerating the servo motor 10a, in particular the individual method steps may be modified, and further optional method steps may be added.

[0039] Another embodiment of the present invention is shown in Fig. 4. The following description and drawings are substantially limited to the differences between the embodiments, and for the similar components shown, especially those having the same reference numbers, reference can be made in principle to the drawings and / or descriptions of the other embodiments, especially to Figs. 1a to 3. To distinguish the respective embodiments, the reference numbers of the embodiments in Figs. 1a to 3 are followed by the letter a, which is replaced by the letter b in the embodiment in Fig. 4.

[0040] In this case, the energy accumulator 18b of the steering system is arranged in parallel with the intermediate circuit capacitance 24b of the steering system. The energy accumulator 18b is configured as a capacitor. Moreover, the energy accumulator 18b is switched on in at least one application case, i.e. in particular when the energy supply by the vehicle battery 16b is interrupted or disturbed, and is thus electrically connected to the intermediate circuit 20b. For this purpose, the steering system includes a switching unit 44b. The switching unit 44b can be supplied with energy via a separate further energy accumulator (not shown) and / or via the vehicle battery 16b. In the latter case, the energy accumulator 18b can be switched on, for example, already when the vehicle is stopped and / or when it is cut off.

[0041] Furthermore, the intermediate circuit capacitance 24b is decoupled from the intermediate circuit 20b in certain applications. For this purpose, the steering device comprises a further switching unit 46b. The further switching unit 46b can likewise be supplied with energy via a separate further energy store (not shown) and / or via the vehicle battery 16b. However, it is basically also conceivable to supply the further switching unit 46b with energy via the energy store 18b. Furthermore, as an alternative, a switchover between the intermediate circuit capacitance 24b and the energy store 18b can also be carried out. Furthermore, the decoupling of the intermediate circuit capacitance 24b can basically be omitted.

[0042] However, also in this embodiment, the energy accumulator 18b is basically charged by the movement of the steering servo motor 10b and is used in at least one application case to supply energy to the steering control unit 12b, the steering monitoring electronics 14b and the steering output electronics 22b.

Claims

1. 1. A method for slowing down a servo motor (10a; 10b) of a steering device, in particular for protection in maintenance operating situations, comprising: the steering device comprises a control unit (12a; 12b) for controlling the servo motor (10a; 10b), a monitoring electronic circuit (14a; 14b) for monitoring the movement of the servo motor (10a; 10b), and an energy accumulator (18a; 18b) operatively connected to the control unit (12a; 12b) and to the monitoring electronic circuit (14a; 14b) and configured differently from a vehicle battery (16a; 16b), a motion of the servo motor (10a; 10b) caused by external forces is monitored by means of the monitoring electronics (14a; 14b) by evaluating a motion characteristic quantity which correlates with the motion of the servo motor (10a; 10b) and in at least one operating state a deceleration process is triggered by means of the control unit (12a; 12b) for decelerating the servo motor (10a; 10b) as a function of the motion characteristic quantity, The method of claim 1, wherein the energy accumulator (18a; 18b) is charged by the movement of the servo motor (10a; 10b) and is used in at least one application case to supply energy to the control unit (12a; 12b) and the monitoring electronics (14a; 14b).

2. 2. The method according to claim 1, wherein the energy accumulator (18a; 18b) is used to supply energy to the control unit (12a; 12b) and the monitoring electronic circuit (14a; 14b) in case of an interruption or failure of the energy supply by at least one vehicle battery (16a; 16b).

3. 3. The method according to claim 1 or 2, wherein the energy accumulator (18a; 18b) is arranged in an intermediate circuit (20a; 20b) between the vehicle battery (16a; 16b) and an output electronic circuit (22a; 22b) of the steering device in terms of circuit technology.

4. 4. The method according to claim 3, wherein an intermediate circuit capacitance (24a) is used as the energy storage (18a).

5. 4. The method according to claim 3, wherein the energy accumulator (18b) is arranged in parallel with an intermediate circuit capacitance (24b) and is switched on in the application.

6. 6. The method according to claim 5, wherein the energy storage (18b) is configured as a capacitor.

7. 7. The method according to claim 5 or 6, wherein the intermediate circuit capacitance (24b) is decoupled in the application.

8. A steering device particularly adapted to carry out the method according to any one of claims 1 to 7, a servo motor (10a; 10b), a control unit (12a; 12b) for controlling the servo motor (10a; 10b), a monitoring electronic circuit (14a; 14b) for monitoring the motion of the servo motor (10a; 10b), and an energy accumulator (18a; 18b) operably connected to the control unit (12a; 12b) and the monitoring electronic circuit (14a; 14b) and configured differently from a vehicle battery (16a; 16b), said monitoring electronic circuit (14a; 14b) is adapted to monitor a movement of said servo motor (10a; 10b) caused by external forces by evaluating a motion characteristic quantity which correlates with a movement of said servo motor (10a; 10b) and to trigger, in at least one operating state, a deceleration process for decelerating said servo motor (10a; 10b) by means of said control unit (12a; 12b) in dependence on said motion characteristic quantity, The energy accumulator (18a; 18b) is configured to be charged by the movement of the servo motor (10a; 10b) and to supply energy to the control unit (12a; 12b) and to the monitoring electronic circuit (14a; 14b) in at least one application case.

9. A vehicle (26a) comprising a steering device according to claim 8.

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