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CN-122029400-A - Measuring device and method for determining the angular position of a target rotatable about an axis

CN122029400ACN 122029400 ACN122029400 ACN 122029400ACN-122029400-A

Abstract

A measuring device for determining the angular position of an object rotatable about an axis is described, which has a stationary coil arrangement, which comprises a transmitting coil and at least two receiving coils, and which also has a rotationally movable, electrically conductive object, wherein the transmitting coil is supplied with a transmitting current, and voltage signals are induced in the receiving coils by the transmitting coil, which voltage signals depend on the angular position of the object. A measuring and evaluating unit is designed to derive an angular position of the target from the amplitude of the voltage signal. According to the invention, the desired value for the phase of the voltage signal is derived from the phase of the transmission current, and the derived angular position of the target is marked as error-free if the phase of the voltage signal corresponds to the desired value within a defined tolerance range.

Inventors

  • Michel Coster

Assignees

  • 科世达汽车电气有限及两合公司

Dates

Publication Date
20260512
Application Date
20241002
Priority Date
20231013

Claims (9)

  1. 1. Measuring device (1) for determining an angular position (phi.T) of a target (T) rotatable about an axis, Having a stationary coil arrangement (2) which comprises at least one transmitting coil (S) and at least one first receiving coil (A) and at least one second receiving coil (B), And having an electrically conductive target (T) which is rotatably movable relative to the coil arrangement (2), Wherein a transmission coil (S) is supplied with a transmission current (I.S) having a defined amplitude (|I.S|), frequency (f.S) and phase (Φ.S), a first and a second voltage signal (U.A, U.B) are induced in the first and the second receiving coil (A, B) by the transmission coil, said voltage signals being dependent on the angular position (Φ.T) of the target (T) relative to the coil arrangement (2), A measuring and evaluating unit (3) is provided, which is designed to detect the voltage signals (U.A, U.B) of the receiving coil (A, B) and to derive the angular position (Φ.T) of the target (T) from the amplitudes (| U.A |, | U.B |) of the voltage signals (U.A, U.B), It is characterized in that the method comprises the steps of, The measuring and evaluating unit (3) is further designed to derive a desired value (EW. phi) for the phase (phiA, phiB) of the voltage signal (U.A, U.B) of the receiving coil (A, B) from the phase (phiS) of the transmission current (I.S), And marking the resulting angular position (Φ.T) of the target (T) as error-free when the phase (ΦA, ΦB) of the voltage signals (U.A, U.B) coincides with the expected value (EW. Φ) within a prescribed tolerance range (TB. Φ).
  2. 2. Measuring device (1) for determining an angular position (phi.T) of a target (T) rotatable about an axis, Having a stationary coil arrangement (2) which comprises at least one transmitting coil (S) and at least one first receiving coil (A) and at least one second receiving coil (B), And having an electrically conductive target (T) which is rotatably movable relative to the coil arrangement (2), Wherein a transmission coil (S) is supplied with a transmission current (I.S) having a defined amplitude (|I.S|), frequency (f.S) and phase (Φ.S), a first and a second voltage signal (U.A, U.B) are induced in the first and the second receiving coil (A, B) by the transmission coil, said voltage signals being dependent on the angular position (Φ.T) of the target (T) relative to the coil arrangement (2), A measuring and evaluating unit (3) is provided, which is designed to detect the voltage signals (U.A, U.B) of the receiving coil (A, B) and to derive the angular position (Φ.T) of the target (T) from the amplitudes (| U.A |, | U.B |) of the voltage signals (U.A, U.B), It is characterized in that the method comprises the steps of, The measuring and evaluating unit (3) is designed to: the modulus of vector U.T is calculated from the amplitude values (| U.A |, | U.B |) of the voltage signals (U.A, U.B), and the resulting angular position (Φ.t) of the target (T) is marked as error-free when the modulus of vector U.T of the voltage signals (U.A, U.B) coincides with the expected value (ew.t) within a prescribed tolerance range (tb.t).
  3. 3. Measuring device according to claim 1 or 2, characterized in that the measuring and evaluating unit (3) is designed to compare and evaluate the phase (Φ.z) and the amplitude (|z|) of the impedance (Z) of at least one of the transmitting coil (S) and/or the receiving coil (A, B) with an expected value (ew.z) within a prescribed tolerance range (tb.z).
  4. 4. The measuring device according to claim 1 or 2, characterized in that the measuring and evaluating unit (3) is formed by a signal processing unit (4) and an evaluating unit (10).
  5. 5. Measuring device according to claim 4, characterized in that the electrical component in the signal processing unit (4) is assessed as being faulty or not faulty in the assessment unit (10) by comparing the amplitude and phase of the input signals (U.A and U.B) of the receiving coils in the electrical component with a previously defined expected value (ew.s) or tolerance range (tb.s).
  6. 6. Measuring device according to claim 4 or 5, characterized in that the signal processing unit (4) is arranged on a single component (IC).
  7. 7. Method for determining an angular position (Φ.t) with a measuring device according to one of the preceding claims, comprising the steps of: A first test, in which the electrical components in the signal processing unit (4) are tested in the evaluation unit (10) for error-free performance, and A second test, in which the coil arrangement (2) is tested in the evaluation unit (10) for the absence of errors in the coil arrangement (2), and A third test, in which the target (Φ.t) is first measured and the subsequent angle is determined in an evaluation unit (10), and the coil arrangement (2) and the signal processing unit (4) are tested for error-free properties of the coil arrangement (2) and the signal processing unit (4), and Furthermore, after the angle of the target (Φ.T) has been determined, the first and second test are repeated again in the evaluation unit (10).
  8. 8. The method of claim 7, wherein the order of the first, second, and third checks is replaceable.
  9. 9. Method according to claim 7, characterized in that the first, second, third and last examination can be applied to any coil arrangement (2) and/or coil system.

Description

Measuring device and method for determining the angular position of a target rotatable about an axis Technical Field The invention relates to a measuring device and a method for determining the angular position of a target rotatable about an axis at a maximum safety-integrity level (ASIL-D). Background Such measuring devices are known from the prior art and are used in particular for determining steering angle sensors (LWS) in the automotive field. The function of LWS is typically based on different physical characteristics. Systems which are currently most excellent in this field are, for example, potentiometer-based systems, optically or magnetically operated systems, and inductive measuring systems, to name a few. The inductive measuring systems mentioned last have advantages over magnetic systems in particular in that they are robust against external influences, in particular external interference fields, and they can distinguish and cope with these external influences significantly better. LWS, which is used as a component in motor vehicles, is always used in safety-relevant applications in motor vehicles today. This fact is mainly due to the function of LWS, which must generally mechanically map the position of the steering wheel within a plurality of turns of the steering wheel in such a way that the position is measured and output absolutely, i.e. uniquely and without errors within each turn. It is also particularly pointed out that in the mass production of the automobile and automobile parts industry today, the cost factor is inferior to functional safety in such components, and plays an important role. In particular in mass production, materials and manufacturing costs must be low. In the field of materials, the number and size of individual microelectronic individual components, in particular integrated circuit modules, is critical. These individual components are currently highly complex, and there is an increasing need for low cost and new solutions or solutions. Furthermore, as mentioned at the outset, these individual components must also have extremely high safety integrity. Furthermore, such high safety integrity presents clear differentiated features for current and future products in the automotive industry. Therefore, in the automotive industry, inductive LWS must meet corresponding safety standards. In particular, an Automotive Safety Integrity Level (ASIL) is defined in ISO 26262, which is directed to categorizing intrinsic safety risks in automotive systems or components. This criterion expresses the degree of risk reduction required to prevent a particular hazard, where ASIL-D represents the highest integrity requirement and ASIL-a represents the lowest integrity requirement. Thus, to meet these safety standards, particularly ASIL grades C and D, a high degree of self-diagnostic capability of inductive LWS is required in order to thus collect systematic and random errors. One known technique to meet these integrity requirements at the highest security integrity level ASIL-D is to use redundancy. Here, two or more independent inductive sensors are generally used in order to measure the same parameter multiple times in different sensor systems and to subsequently determine it. In the present case, this means in particular that the angular position of a rotationally movable metal object is determined and ascertained. However, the introduction of redundant sensors is undesirable from a current perspective, as they increase the overall cost of the system and require additional area and interfacing on the circuit board. Furthermore, the introduction of redundant sensors is undesirable in another respect, since they can continuously increase the design complexity of the system and can also cause additional errors (so-called co-occurrence errors) which are generated by the redundancy of the coils, in particular the multiplication of the coil system. Thus, the challenges described above for achieving the highest security integrity level (ASIL-D) have not been achieved heretofore in the known prior art. This fact can also be seen in DE 11 2021 002 293 T5. In this document, for example, a method is described in which it is ensured that a system can be classified as safe according to certain criteria. The system relies on the use of an inductive position system. In this system, angular deviations caused by inaccuracy of the switching system are monitored. Thus, only a solution for an inductive position system in a redundant circuit (AFE channel) is disclosed here, but no corresponding checking of possible errors of the sensor element itself is involved. Furthermore, an inductive position sensor for determining the position of a movable element is disclosed in US 2011,0101968 A1. The position sensor is composed of two subsystems, each having two transmission units, which are arranged in an LC oscillating circuit on the movable element and in a receiving coil with an evaluation unit. This is thus