EP3079968A1

EP3079968A1 - Method and device for determining an angle of rotation and/or a rotational speed of a steering shaft

Info

Publication number: EP3079968A1
Application number: EP14795834.2A
Authority: EP
Inventors: Andreas Füssl; Notker Amann
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2013-12-13
Filing date: 2014-11-11
Publication date: 2016-10-19
Also published as: JP2017506867A; US10065678B2; JP6503358B2; CN105813923A; DE102013225877A1; CN105813923B; WO2015086235A1; US20160304125A1

Abstract

The invention relates to a method for determining an angle of rotation and/or a rotational speed of a motor shaft (110) of a motor (105), wherein the motor (105) is designed to cause a control element (115, 115a) to move translationally in relation to the motor (105). The method comprises a step of reading in a motion signal by means of an interface from at least one sensor element (120) arranged outside the motor (105), wherein the motion signal represents a translational motion of the control element (115, 115a) in relation to the motor (105). Furthermore, the method comprises a step of determining the angle of rotation and/or the rotational speed of the motor shaft (110) by using the motion signal.

Description

METHOD AND DEVICE FOR DETERMINING A TURNING ANGLE AND / OR A SPEED OF A STEERING SHAFT

The present invention relates to a method for determining a rotation angle and / or a rotational speed of a motor shaft of an engine, to a corresponding device, to a steering device of a vehicle and to a corresponding computer program product.

Rear-axle steering systems, which are in series or in a series development, can be an actuator, e.g. variable length handlebar, in particular wishbone, which is driven by a motor. To control the motor, a rotor position sensor is usually required. In addition, in such a control system, an absolute position sensor can be installed, which is designed to determine a translational or axial movement of the actuator. To the

Driving the motor usually requires both a current motor position and a current motor speed of rotation. These two sizes are for example by means of a mounted on a motor shaft

Motor position sensor determined.

DE 10 2010 052 917 A1 discloses a controller for a steering device of a motor vehicle.

Against this background, the approach presented here provides an improved method for determining a rotational angle and / or a rotational speed of a motor shaft of an engine, a corresponding device, a steering device of a

Vehicle and finally a corresponding computer program product according to the main claims. Advantageous embodiments will be apparent from the

Subclaims and the description below.

The present approach provides a method of determining a rotational angle and / or a rotational speed of a motor shaft of an engine, wherein the motor is configured to translate an actuator into translational motion relative to the engine. The method comprises the following steps: Reading a motion signal by means of an interface of at least one sensor element arranged outside the motor, wherein the

Motion signal represents a translational movement of the actuating element relative to the engine; and

Determining the angle of rotation and / or the speed of the motor shaft using the motion signal.

An angle of rotation can be understood as meaning an angle of a rotation of the motor shaft about a longitudinal axis of the motor shaft. A speed may be understood to mean a number of rotations of the motor shaft about the longitudinal axis of the motor shaft during a predetermined time unit. A motor shaft can be understood to mean an element of a motor which is designed to be set into rotary motion when the motor is operated. A motor can be understood as a machine for performing mechanical work. The engine may be, for example, an electric motor. The motor shaft may be mechanically coupled to an actuator. An adjusting element may be understood to mean a machine element which is designed to be displaced relative to the motor during operation of the motor in a translatory movement.

For example, the adjusting element can be a lever or a rod which is displaceably arranged along the motor shaft and is coupled to the motor shaft by means of a ball ramp spindle, trapezoidal spindle and circulating spindle, for example. In particular, the adjusting element in a handlebar, in particular wishbone for a motor vehicle, included, or forms this to form the handlebar variable in its length. If this link is on the one hand connected to the body and on the other hand connected to at least one wheel carrier, a change in length can exert a steering movement on the wheel carrier. The wheel carrier is pivoted about the vertical axis on the vehicle. A translatory movement of the actuating element can be understood to mean a movement in which all points of the actuating element are displaced in the same direction relative to the motor. Outside the motor can be arranged at least one sensor element for detecting the translational movement. For example, that can Sensor element to be mounted on the actuator. By a sensor element, for example, a displacement sensor can be understood. The sensor element may be designed to control the translational movement, for example based on a resistance change, a variable inductance, a variable capacitance, a variable luminous flux, a count of pulses and / or a pulse

To record transit time measurement.

The present approach is based on the finding that it is possible to save a motor position sensor mounted on a motor shaft for detecting a rotation angle or a rotational speed of the motor shaft. By means of a method described below, the two necessary for a motor control signals of the rotation angle and the speed despite the missing

Motor position sensors are provided cost-effectively and space-saving in order to be able to operate the motor control correctly and dynamically.

According to an embodiment of the present approach, in the step of determining using the motion signal, a speed of the translational motion may be determined to determine the speed. In this case, the speed can be determined, for example, by derivation. Using the speed of translational motion, the speed of the motor shaft can be determined with sufficient reliability and accuracy.

Furthermore, in the step of determining the rotation angle and / or the rotational speed can be determined using a motion equation and / or taking into account a transmission ratio of a mechanical transmission chain between the motor and the actuator. An equation of motion can generally be understood as meaning a differential equation of the second order or else a system of differential equations of a second order. Using the equation of motion, a spatial and temporal evolution of a

mechanical system under the influence of external influences. The mechanical transmission chain, for example, a transmission, a

Belt drive and / or a threaded spindle include. By means of the mechanical transmission chain, a rotational movement of the motor shaft in the translational movement, in particular a threaded spindle to be converted. In this case, the mechanical transmission chain can be realized with a predetermined transmission ratio. By this embodiment of the

This approach ensures a correct determination of the angle of rotation and / or the speed.

Due to the mechanical coupling between translational and rotational movement through the mechanical transmission elements can be closed with sufficient reliability and accuracy using the translational sensors on the angular position of the motor shaft or rotation angle of the motor shaft.

Further, in the step of determining, the rotational angle and / or the rotational speed may be further determined using a linear conversion, a

Observer structure and / or a Kalman filter are determined. Under a linear conversion, for example, a linear conversion of

Speed of translational motion in the speed can be understood. An observer structure can be understood as a system that reconstructs unmeasurable quantities from given input and output variables of an observed reference system. The observer structure may include, for example, the Luenberger observer. A Kalman filter can be understood as a filter for removing disturbances caused by measuring devices. By this embodiment of the present approach, inaccuracies in the determination of the rotation angle and / or the speed can be avoided.

In accordance with another embodiment of the present approach, the method may include a step of determining a motor shaft position when the motor shaft is at rest. Herein, in the step of determining, the rotation angle may be further determined by using the motor shaft position. By determining the motor shaft position, a reference point for determining the angle of rotation can be determined. In addition, in the step of determining the engine with a

Test signal are applied to determine the motor shaft position. A test signal may be understood as an electrical signal, such as a voltage signal injected into an electric motor. By means of the test signal, a position of a rotor of the electric motor can be determined when the rotor is at a standstill.

In the step of determining, the actuating element can be blocked at least temporarily in order to prevent an adjusting movement.

The method may include a step of receiving a position signal via the interface to the at least one sensor element. The

Position signal may represent an absolute position of the actuator. In the step of determining, the motor shaft position may be further checked by using the position signal. This can be a reliability in the

Determining the motor shaft position can be increased.

The present approach further provides a device for determining a rotational angle and / or a rotational speed of a motor shaft of an engine, wherein the motor is designed to set an actuating element in a translatory movement relative to the motor, the device having the following features:

A read-in unit for reading in a motion signal via a

Interface to at least one arranged outside the engine

Sensor element, wherein the movement signal represents a translational movement of the actuating element relative to the motor; and a detection unit for detecting the rotation angle and / or the rotational speed of the motor shaft by using the motion signal.

A device may be an electrical device that processes sensor signals and outputs control signals in response thereto. The device may have one or more suitable interfaces, the hard- and / or can be designed by software. For example, in a hardware configuration, the interfaces may be part of an integrated circuit in which functions of the device are implemented. The interfaces may also be their own integrated circuits or at least partially consist of discrete components. In a software training, the interfaces

Software modules that are present for example on a microcontroller in addition to other software modules.

Finally, the present approach provides a steering device of a

A vehicle, wherein the steering device comprises the following features: an adjusting element for adjusting a steering angle of the vehicle; a motor configured to translate the actuator into translational motion relative to the engine, the engine including apparatus according to a previously described embodiment for detecting a rotational angle and / or a rotational speed of a motor shaft of the engine; and at least one sensor element arranged outside the motor for detecting the translational movement of the actuating element, wherein the at least one sensor element is connected to the device via an interface.

By a steering device, for example, a device for steering a front or rear axle of a vehicle can be understood. A vehicle may be understood to mean a motor vehicle, in particular a two-lane motor vehicle such as a car or truck.

An advantage is also a computer program product with program code, which on a machine-readable carrier such as a semiconductor memory, a

Hard disk memory or an optical memory can be stored and for carrying out the method according to one of the above

Embodiments is used when the program is executed on a computer or a device. The invention will be described by way of example with reference to the accompanying drawings. Show it:

Fig. 1 is a schematic representation of an adjusting device for use with a device according to an embodiment of the present invention;

FIG. 2 shows a schematic illustration of an adjusting device for use with a device according to an embodiment of the present invention; FIG.

3 is a schematic illustration of a vehicle having steering devices according to embodiments of the present invention;

4 is a flowchart of an embodiment of a method for determining a rotation angle and / or a rotational speed of a motor shaft of an engine; and

Fig. 5 is a block diagram of an embodiment of a device for determining a rotation angle and / or a rotational speed of a motor shaft of a motor.

In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and similarly acting, wherein a repeated description of these elements is omitted.

1 shows a schematic representation of an adjusting device 100 for use with a device according to an embodiment of the

present invention. The adjusting device 100 comprises a motor 105 with a motor shaft 1 10, an actuating element 1 15 and a sensor 120. The motor 105 is arranged coaxially about the actuating element 15 1. The actuator 1 15 is in the

Motor shaft 1 10 arranged and along a longitudinal axis 122 of the motor shaft 1 10 translationally displaceable. The sensor 120 is attached by way of example to an end region of the actuating element 15 located outside of the motor 105. Alternatively, the sensor 120 may be fastened to a housing of the motor 105 or to a structure of the adjusting device 100, such as a housing of the adjusting device 100, surrounding the adjusting element 15. The motor 105 is configured to set the motor shaft 1 10 in a rotational movement about the longitudinal axis 122. For example, the engine 105 is as

Electric motor and the motor shaft 1 10 designed as a rotor shaft of a rotor of the electric motor. The actuator 1 15 is designed as a threaded spindle to be offset by the rotational movement of the motor shaft 1 10 in a translational movement along the longitudinal axis 122. The motor shaft includes or drives one

Spindle nut 1 1 1, which meshes with the thread of the threaded spindle 1 15. The sensor 120 is designed to detect the translational movement of the actuating element 1 15 within a control range 125 of the control element 15 and a corresponding motion signal to an interface to a device not shown in FIG. 1 for determining a rotation angle and / or a speed of Output motor shaft 1 10.

FIG. 2 shows a schematic illustration of an adjusting device 100 for use with a device according to an exemplary embodiment of the invention

present invention. In contrast to FIG. 1, FIG. 2 shows a cross section transverse to the longitudinal axis 122. When the motor 105 is operated, the motor shaft 110 is rotated about the longitudinal axis 122 by a speed dependent on a rotational speed n of the motor 105. The rotational speed n and the rotational angle α can be determined using a method described below with reference to FIG. 4 without the use of an engine-internal sensor.

FIG. 3 shows a schematic representation of a vehicle 300 with two steering devices 305, 305 a according to exemplary embodiments A and B of the drawings

present invention. The vehicle 300 is realized as a two-lane vehicle. In the vehicle 300, the adjusting device 100, 100a shown in Figures 1 and 2 is installed in two different versions. Here, an end portion of the actuating element 1 15, 1 15a is movably mounted on a pivotally mounted stub axle 310 of the vehicle 300.

On a side opposite the steering knuckle 310 vehicle side another stub axle 315 is arranged. The further stub axle 315 is movably connected to the stub axle 310 via a transverse link 320. The lateral thinker 320 is configured to transmit a steering angle change of the wheel carrier 312 caused by an adjustment of the actuating element 115 to the further steering knuckle 315 and thus to the further wheel carrier 312a.

The adjusting device 100, 100a comprises a control unit 325, 325a, which is connected to the sensor 120 and the motor 105 via corresponding interfaces of the

Vehicle 300 is connected. The control unit 325 is designed to detect the motion signal provided by the sensor 120, 120a, which is the translational signal

Movement of the actuating element 115, 115a represents, read in and under

Use of the motion signal to determine the rotation angle and / or the rotational speed of the motor shaft of the motor 105.

According to the embodiments of the present invention, a sensorless motor drive in Hinterachslenkungsanwendungen means

Replica of an engine speed with the elimination of a motor position sensor

intended. In this case, a steering device 305 realized as a rear-axle steering actuator 306, 306a has an absolute position sensor 120, 120a which cooperates with an actuating element 115. The adjusting element is designed to initiate a steering movement on a rear axle of the vehicle 300. The actuator 115 is connected via a positive machine element, such as e.g. a spindle nut 111 connected to the motor shaft. As adjusting elements, for example

Recirculating ball or ball ramp spindles and trapezoidal spindles are used. Alternatively, also belt drives or wheel gear offer, which can be used as a coupling element between the motor shaft and actuator. In FIG. 3, a steering system via a single actuator, central actuator 305 is shown in embodiment A, embodiment B shows two individual actuators 305a, each having its own control device 325a.

4 shows a flow chart of an embodiment of a method 400 for determining a rotation angle and / or a rotational speed of a motor shaft of an engine. The method includes a step 405 of reading a

Motion signal via an interface to at least one arranged outside the motor sensor, wherein the movement signal is a translational movement represents the actuating element relative to the engine. Furthermore, the method comprises a step 410 of determining the angle of rotation and / or the rotational speed of the

Motor shaft using the motion signal.

The sensor 120, 120a shown in FIGS. 1 and 3 is designed, for example, to act or to detect over the entire control range 125. An absolute position detection is not mandatory here.

For example, a relative detection is sufficient for a speed determination. From the detected translational motion is a linear

Traversing speed determined, for example by derivation. This is under

Consideration of an equation of motion and circumstances of a

mechanical transmission chain converted into an equivalent engine speed n, as shown in Fig. 2. A calculation can be made for example via a linear conversion, an observer structure or a Kalman filter. Alternative to

Rear axle steering can be the detection of the linear positioning movement of a

Actuator be used in a vehicle transmission. The

Actuator can e.g. in an automatic transmission, engage a gear or operate a selector lever. The position of the actuator is in the case of

Transmission control supplied.

According to a further embodiment of the present invention, the sensorless motor drive can also be done by means of position simulation.

Here, an estimate of the engine speed n with an estimate of a

Motor angle α combined.

When an actuator 100, 100a is initialized, a position of a rotor of an electric motor 105 is determined by an injection method. Injection methods are methods with active current injection. Here, the motor 105 with a

Test signal applied to determine the position of the rotor at a standstill.

This is optionally done in a state in which the actuator 100 is blocked by a lock, so that no adjusting movement can take place. For the determination of the motor shaft position additionally the over the

Injection method determined position with a position information of the absolute translational position sensor 120 are compared and checked.

Thereafter, the absolute position sensor 120 detects a translational

Motion or an absolute, linear position. From this movement or position, an equivalent rotational motor position α is calculated taking into account the equation of motion and the conditions of the mechanical transmission chain.

The calculation can be done as in the case of speed simulation via a linear conversion, an observer structure or a Kalman filter.

The method described here can generally be applied to electric actuators 100, 100a, which are translational

Movement device 115 having a sensor 120, 120a for detecting a position of the movement means 115, wherein the movement means 115 by a transmission, a mechanical coupling o. Ä. with a motor 105

connected is.

5 shows a block diagram of an embodiment of a device 500 for determining a rotation angle and / or a rotational speed of a motor shaft of an engine. The device 500 is, for example, the controller 325, 325a shown in FIG. The device 500 comprises a read-in unit 505 for reading in a movement signal via an interface to at least one sensor arranged outside the motor, the movement signal being a translatory movement of the actuating element 115 relative to the motor

represents. The read-in unit 505 is connected to a determination unit 510. The determination unit 510 is designed to determine the rotation angle and / or the rotational speed of the motor shaft using the motion signal.

The determination unit 510 can be equipped with an optional control unit of

Device 500 connected. The control unit may be designed to be under Use the rotation angle and / or the speed of the motor shaft output a control signal for controlling the motor to an interface to the engine.

The embodiments described and shown in the figures are chosen only by way of example. Different embodiments may be combined together or in relation to individual features. Also, an embodiment can be supplemented by features of another embodiment.

Furthermore, method steps according to the invention can be repeated as well as carried out in a sequence other than that described.

If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, this can be read so that the embodiment according to one embodiment, both the first feature and the second feature and according to another embodiment, either only the first Feature or only the second feature.

reference numeral

100, 100a actuator

105 engine

1 10 motor shaft

1 1 1 spindle nut

1 15, 1 15a Actuator, threaded spindle, translatory

mover

1 16 handlebars

120, 120a sensor element

122 longitudinal axis

125 setting range

300 vehicle

305, 305a steering device

306, 306a Steller, individual plates, central plate

310 knuckle

312 wheel carrier

315 additional knuckle

320 wishbone

325, 325a control unit

400 method for determining a rotation angle and / or a

rotation speed

405 reading a motion signal

410 Determining the angle of rotation and / or the speed

500 Device for determining a rotation angle and / or a

rotation speed

505 reading unit

510 determination unit

α rotation angle

n speed

A, B embodiments of the steering device

Claims

claims

1 . Method (400) for determining a rotational angle α and / or a rotational speed n of a motor shaft (1 10) of a motor (105), wherein the motor (105) is designed to move an actuating element (1 15) into a translatory movement relative to the motor (105), the method (400) comprising the steps of:

Reading in (405) a motion signal by means of an interface of at least one sensor element (120, 120a) arranged outside the motor (105), the motion signal being a translatory movement of the sensor

Actuator (1 15) relative to the motor (105) represented; and

Determining (410) the rotation angle α and / or the rotational speed n of the motor shaft (1 10) using the movement signal.

A method (400) according to claim 1, characterized in that in the step (410) of determining using the motion signal a

Speed of translational motion is determined to determine the speed n.

3. Method (400) according to one of the preceding claims, characterized in that in step (410) of the determination of the rotation angle α and / or the rotational speed n further using an equation of motion and / or taking into account a transmission ratio of a mechanical

Transmission chain between the motor (105) and the actuating element (1 15, 1 15a) is determined.

4. Method (400) according to one of the preceding claims, characterized in that in the step (410) of determining the rotational angle α and / or the rotational speed n further using a linear conversion and / or an observer structure and / or a Kalman filter is determined.

5. The method (400) according to one of the preceding claims, characterized by a step of determining a motor shaft position at standstill of the motor shaft (1 10), wherein in the step (410) of the determining the

Angle of rotation α is also determined using the motor shaft position.

A method (400) according to claim 5, characterized in that in the step of determining the motor (105) is applied with a test signal to determine the motor shaft position.

7. The method (400) according to claim 5 or 6, characterized in that in the step of determining the actuating element (1 15, 1 15a) is at least temporarily blocked.

8. The method according to claim 5, further comprising a step of receiving a position signal via the interface to the at least one sensor element, wherein the position signal represents an absolute position of the actuating element , wherein in the step of

Determining the motor shaft position is further checked using the position signal.

9. Device (500) for determining a rotational angle α and / or a rotational speed n of a motor shaft (1 10) of a motor (105), wherein the motor (105) is adapted to an adjusting element (1 15, 1 15a) in a translational movement relative to the motor (105), the device (500) having the following features:

- A read-in unit (505) for reading a movement signal by means of an interface of at least one outside the motor (105) arranged sensor element (120), wherein the movement signal represents a translational movement of the actuating element (1 15, 1 15a) relative to the motor (105) ; and - A determination unit (510) for determining the rotation angle α and / or the rotational speed n of the motor shaft (1 10) using the

Motion signal.

10. A steering device (305) of a vehicle (300), wherein the steering device (305) has the following features:

- An actuator (1 15, 1 15a) for adjusting a steering angle of the

Vehicle (300);

- A motor (105) which is adapted to the actuator (1 15, 1 15a) in a translational movement relative to the motor (105) to move, wherein the motor (105) comprises a device (500) according to claim 9, to determine a rotational angle α and / or a rotational speed n of a motor shaft (1 10) of the motor (105); and

- At least one outside of the motor (105) arranged sensor element (120) for detecting the translational movement of the actuating element (1 15, 1 15a), wherein the at least one sensor element (120) via an interface with the device (500) is connected.

1 1. A computer program product with program code for carrying out the method (400) according to one of claims 1 to 8, when the

Computer program product on a device (500) is executed.