METHOD FOR DETECTING THE POSITION OF A MOVABLE PART AND A SYSTEM FOR EXECUTING THE METHOD

Description

[0001] The invention relates to a method for detecting the position of a movable part and a system for carrying out the method.

[0002] It is generally known that a sensor can be used for a method of detecting the position of a movable part.

[0003] From the DE 2015 / 112634 A1 The closest prior art is a method for detecting the angular position of a rotatably mounted body.

[0004] From the DE 603 ​​10 860 T2 An angle measuring device is known.

[0005] From the JP 2014 122885 A an engine control is known.

[0006] From the DE 10 2006043878 A1 A motor control device is known.

[0007] From the JP H01 94217 A is an angle sensor with automatic amplitude correction.

[0008] The invention is therefore based on the object of correcting the sensor signals generated by a sensor for angle detection.

[0009] According to the invention, the object is achieved by the method according to the features specified in claim 1.

[0010] Important features of the invention in the method are that the method is provided for detecting the position of a movable part, in particular for detecting the angular position of a rotatably mounted part or for detecting the linear position of a linearly movable part, by means of a sensor which has a first signal, in particular a sine signal, and a second signal, in particular a cosine signal, as sensor signals encoding the position, wherein the position detected by the sensor is encoded by means of the first and second signals, wherein an actual variable is determined from the sensor signals in a time-recurring manner, wherein the determination of a control value, in particular of a respectively updated control value, is triggered by a trigger signal, in particular a respective trigger signal, in particular by a trigger pulse, wherein the determination of the control value is carried out in such a way that the actual variable is regulated towards a target value, in particular wherein the control value only changes with the next determination triggered by a respective further trigger signal, in particular wherein the control value determined by the determination triggered by the trigger signal remains unchanged until the temporally subsequent and / or respective further trigger signal.

[0011] The advantage here is that the signals generated by the sensor, which encode the detected position, in particular the angle, i.e. the angular position of the part, or the linear position of the part, can be controlled to a setpoint without overriding safety-related monitoring.

[0012] While the detected angular position, encoded by the signals, passes through an electrical angle, no correction is performed as long as a minimum time t is not exceeded. This means that safety-related monitoring of the sensor signals is capable of detecting an error. For example, a defect occurs such that one or both signals lose amplitude. This is detectable because no correction of the signals is performed. Only when the electrical period has been completed or the time period t has elapsed is a control value determined that causes a correction. The control value is determined such that the peak value, in particular the amplitude, of the signals is the same.For example, the signals are designed as sine signals and cosine signals, and the control system causes the pointer, which is coded from the sine signals and cosine signals, to move through a circle, i.e. to deviate from the desired circle with a given radius with the smallest possible eccentricity.

[0013] Thus, safety-related monitoring can be carried out during the passage of an electrical period and a new control value can be determined at the beginning of the next electrical period in order, for example, to readjust the luminous intensity of an optical source of the sensor or to readjust a receiving-side amplification factor of the sensor.

[0014] In an advantageous embodiment, the control value controls or is a sensor excitation voltage or current and / or a sensor gain factor. This has the advantage of allowing for easy readjustment of the signals.

[0015] In an advantageous embodiment, a trigger signal is triggered when the position coded by means of the first and second signals by a distance corresponding to the electrical period, in particular angular length or linear length, and / or by a maximum distance, in particular angular length or linear length, which can be uniquely coded by means of the first and second signals, has changed since the previously triggered trigger signal. The advantage here is that the control value is not changed between two trigger signals, thus allowing safety-related monitoring of the signals to be carried out without interruption.

[0016] In an advantageous embodiment, a trigger signal is triggered when a time period t has elapsed since the previously triggered trigger signal, in particular, where the time period t is greater than the period of the first signal, when the rotational speed of the part is so high or at its maximum that the position can just barely be clearly determined. This is advantageous in that an updated determination of the control value can be carried out even when the part is at a standstill, at least after the start of the time period t.

[0017] In an advantageous embodiment, the actual value is calculated as the square root of a sum, which is calculated as the sum of the square of the value of the respective current first signal and the square of the value of the respective current second signal. This is advantageous in that a radial distance can be easily determined whose abscissa value corresponds to the first signal and whose ordinate value corresponds to the second signal.

[0018] In an advantageous embodiment, the actual variable is formed as a pair of the currently determined amplitude of the first signal and the currently determined amplitude of the second signal, with the target variable also being a pair of tuple, and a pair of control values ​​being determined instead of the control value. The advantage here is that each of the two amplitudes of the sensor signals can be adjusted, i.e., corrected, separately.

[0019] According to the invention, the object of correcting the sensor signals generated by a sensor for angle detection is also achieved by a system according to claim 6.

[0020] Important features of the system for carrying out the above-mentioned method are that the first and second signals are fed to an evaluation unit as well as to a timing element and also to a measuring element, wherein the evaluation unit is designed to determine an actual variable, in particular to determine a moving average of an actual variable, wherein the timer is designed to generate a trigger signal after a time period t has elapsed after the last generated trigger signal, wherein the measuring element is designed to generate a trigger signal after an electrical period has passed after the last generated trigger signal, wherein a controller element is designed to carry out a determination of an updated control value triggered in each case by a trigger signal.

[0021] The advantage of this is that a trigger signal is generated every time an electrical period or a time period t has elapsed, triggering the determination of an updated control value. This ensures that the control value is only determined after a new trigger signal arrives, thus preventing disruption to the safety-related monitoring of the sensor's signals.

[0022] In an advantageous embodiment, the output signal generated by the controller element and containing the control value the current flowing through a light source, in particular an LED, of the sensor and / or the amplification factor of a unit of the sensor evaluating the signal of a light-sensitive sensor element is controlled, or the amplitude of an alternating electrical quantity, such as current or voltage, of a stationary winding acting as a primary winding is controlled, wherein a secondary winding is firmly connected to the part.

[0023] The advantage here is that after each trigger signal, the luminous intensity, i.e. light intensity, of the sensor's illuminant and / or the sensor part arranged on the receiving side, i.e. firmly connected to the part, is changed in order to achieve the target value.

[0024] In an advantageous embodiment, the sensor signals are fed to a unit for safety-related monitoring. The advantage here is that such monitoring can be carried out between trigger signals and is not distorted by updated control values.

[0025] Further advantages arise from the subclaims.

[0026] The invention will now be explained in more detail with the aid of schematic illustrations: In the Figure 1 A method according to the invention for correcting sensor signals is schematically outlined.

[0027] As in the Figure 1As shown, a sensor generates a sine signal S1 and a cosine signal. For this purpose, sensor 1 is a linear displacement measuring system or angle measuring system for detecting the position, in particular the linear position or angular position, of a movable part, in particular a linearly or rotationally movable part.

[0028] For example, sensor 1 detects the angular position of a rotatably mounted part. The part has permanent magnets arranged one behind the other in the circumferential direction, regularly spaced from one another, and alternately magnetized in opposite directions in the circumferential direction. A magnet-sensitive, stationary sensor element thus generates a sine signal S1 upon rotation of the part. This signal has a so-called electrical period length L, which is 720° / N, where N is the number of permanent magnets on the circumference. Another sensor element, which is also stationary at a distance L / 4 in the circumferential direction, generates a cosine signal S2.

[0029] The two signals S1 and S2 are fed to an evaluation unit 4, which uses them to calculate an actual value, such as an actual value R_ist of the radius vector formed from the sine signal S1 and the cosine signal S2.

[0030] This actual value R_ist is always determined repeatedly, in particular quasi-continuously, and preferably smoothed, in particular as a moving average or the like.

[0031] According to the invention, the measuring element 3 determines the distance traveled by the movably arranged part and generates a trigger signal when the electrical period length L has been covered.

[0032] This trigger signal enables the determination of a new control value, which is determined by a controller element 6 by comparing the actual variable R_actual with a predetermined setpoint variable R_setpoint and determining such a control value so that the actual variable R_actual is controlled towards the setpoint variable R_setpoint.

[0033] The next control value is therefore only determined and effective with the next trigger signal.

[0034] In this way, phase-dependent errors are not corrected during the electrical period length L, but remain detectable. The radial distance, calculated in the example as the square root of the sum of the square of the sine signal and the square of the cosine signal and determined as a moving average, is thus controlled to a setpoint, although the control value is changed only once per electrical period.

[0035] In addition to the measuring element 3, a timing element 2 is provided, which can also generate a trigger signal. If the movement of the movable part is very slow, the timing element 2 generates a trigger signal after a time period t to trigger the determination of the next control value by the control element 6.

[0036] In this way, according to the invention, a control value is determined only once per electrical period as long as the speed or rotational speed is above a threshold value, and otherwise after a maximum time, namely the time period t.

[0037] The control value controls an excitation amplitude in sensor 1 or a gain factor in sensor 1.

[0038] For example, sensor 1 has a secondary winding inductively coupled to a primary winding. The primary winding is supplied by a primary alternating voltage, the amplitude of which, i.e., excitation amplitude, is controlled by the control value. Instead of or in addition to the control value, a gain factor can be controlled when generating the sine signal and / or the cosine signal. In this way, the actual variable can also be adjusted to a desired variable, in particular a desired value.

[0039] Alternatively, the sensor is designed as an optical sensor, with a stationary light source whose intensity is controlled by the control value. Instead of or in addition to the control value, an amplification factor can be controlled when generating the sine signal and / or the cosine signal. In this way, the actual variable can also be adjusted to a desired variable, in particular a desired value. If the light source is designed as an LED, the intensity can be controlled by the current flowing through the LED.

[0040] In further embodiments according to the invention, a tuple of two is used as the actual variable R_actual, in particular the tuple composed of the amplitude of the sine signal s1 and the amplitude of the cosine signal S2. The setpoint variable then also consists of two values, which may also be equal. In this case, the manipulated variable also consists of a tuple of two. Thus, the amplitudes of the sensor signals (S1, S2) are then controlled from the manipulated variable to a respective, in particular identical, setpoint value. List of reference symbols

[0041] 1 Sensor 2 Time element 3 Measuring element 4 Evaluation unit 5 Actuator 6 Controller element S1 sine signal S2 cosine signal R_actual vector R-target target vector

Claims

1. Method for detecting the position of a movable component, in particular for detecting the angular position of a rotatably mounted component or for detecting the linear position of a component arranged in a linearly movable manner, by means of a sensor (1) that comprises, as the sensor signals encoding the position, a first signal, in particular a sine signal (S1), and a second signal, in particular a cosine signal (S2), wherein the position detected by the sensor (1) is encoded by means of the first and the second signal, wherein an actual variable (r_ist) is determined from the sensor signals recurrently over time, wherein the determination of a manipulated value, in particular of a most recently updated manipulated value, is triggered by a trigger signal, in particular each trigger signal, in particular by a trigger pulse, wherein the manipulated value is determined such that the actual variable is controlled towards a target variable (r_soll), in particular wherein the manipulated value only changes upon each subsequent determination triggered by each further trigger signal, in particular wherein the manipulated value determined by the determination triggered by the trigger signal remains unchanged until the next trigger signal chronologically and / or each further trigger signal, characterised in that a trigger signal is triggered when the position encoded by means of the first and the second signal has changed - by a distance, in particular an angular length or linear length, corresponding to the electrical period of the first and the second signal, - or by a maximum distance, in particular angular length or linear length, that can be unambiguously encoded by means of the first and the second signal, since the latest triggered trigger signal.

2. Method according to claim 1, characterised in that the manipulated value either controls or is an excitation voltage or an excitation current of the sensor (1) and / or a gain factor of the sensor (1).

3. Method according to any of the preceding claims, characterised in that a trigger signal is triggered when a time period t since the latest triggered trigger signal has elapsed, in particular wherein the time period t is greater than the period duration of the first signal when the rotational speed of the movable component is either so great or at such a maximum that the position can only just be clearly detected.

4. Method according to any of the preceding claims, characterised in that the actual variable is generated as the root of a sum that is generated as the sum of the square of the value of the current first signal and the square of the value of the current second signal, or in that the actual variable is generated as a two-tuple of the currently determined amplitude of the first signal and the currently determined amplitude of the second signal, wherein the target variable is likewise a two-tuple, and a two-tuple of manipulated values is determined instead of the manipulated value.

5. Method according to any of the preceding claims, characterised in that the signals of the sensor (1) are monitored between each two successive trigger signals, in particular wherein an error is indicated and / or relayed when the peak values, amplitudes or the magnitude of the phasor encoded by the two signals changes.

6. System for carrying out a method according to any of the preceding claims, comprising an evaluation unit (4), a timer (2), a measuring member (3) and a controller member (6), wherein the first signal (S1) and the second signal (S2) are supplied to the evaluation unit (4) and also to the timer (2) and the measuring member (3), wherein the evaluation unit (4) is configured to be suitable for determining the actual variable (r_ist), in particular for determining a moving average of the actual variable, wherein the timer (2) is configured to be suitable for generating a trigger signal once a time period t has elapsed following the most recently generated trigger signal, wherein the measuring member (3) is configured to be suitable for generating a trigger signal once an electrical period of the first and the second signal has been run through following the most recently generated trigger signal, wherein the controller member (6) is configured to be suitable for carrying out a determination, in each case triggered by a trigger signal, of an updated manipulated value, characterised in that the system is configured such that a trigger signal is triggered when the position encoded by means of the first and the second signal has changed - by a distance, in particular an angular length or linear length, corresponding to the electrical period, - or by a maximum distance, in particular angular length or linear length, that can be unambiguously encoded by means of the first and the second signal, since the latest triggered trigger signal.

7. System according to claim 6, characterised in that by means of the output signal that is generated by the controller member (6) and contains the manipulated value, - the current flowing through a lamp, in particular an LED, of the sensor (1) and / or the gain factor of a unit of the sensor (1) that evaluates the signal of a light-sensitive sensor element is / are controlled, - or the amplitude of an electrical alternating variable, such as the current or voltage, of an immovably arranged winding acting as the primary winding is controlled, wherein a secondary winding is rigidly connected to the movable component.

8. System according to claim 6 or claim 7, characterised in that the signals of the sensor (1) are supplied to a monitoring unit.