Over-the-air sensor data exchange for performance improvement, feature expansion and increasing the database for sensor development (EZ class 0421)

Abstract

The invention relates to a method for operating a MEMS sensor (10), wherein uncleaned sensor raw data (SR) are generated during the operation of the MEMS sensor (10), wherein, prior to updating an operating procedure, cleaned first sensor output data (SA1) are generated based on the uncleaned sensor raw data (SR) according to a defined first compensation rule, wherein the first sensor output data (SA1) are made available in a first output register (35) for external transmission, in particular to an external control unit (100), wherein the first compensation rule is determined based on first compensation parameters (KP1) which are stored in a non-volatile first memory (34) of the MEMS sensor (10).wherein in an update step (A1) of the operating procedure, second compensation parameters (KP2) are transmitted from an external data processing system (110) to the MEMS sensor (10) and stored in a second memory (37) of the MEMS sensor (10), wherein a second compensation rule is determined based on the second compensation parameters (KP), wherein, during operation of the MEMS sensor (10), after updating the operating procedure based on the uncorrected sensor raw data (SR), second sensor output data (SA2) are generated according to the second compensation rule, wherein the second sensor output data (SA2) are made available in a second output register (39) for external transmission, in particular to the external control unit (100). The invention further relates to a MEMS sensor (10) configured to carry out the presented method,

Description

[0001] The invention relates to a method for manufacturing a MEMS sensor with a microelectromechanical system and a MEMS sensor manufactured according to the method, which can be designed, for example, as a pressure, ultrasonic or, particularly preferably, inertial sensor. State of the art

[0002] Inertial sensors, particularly yaw rate and / or acceleration sensors based on microelectromechanical systems (MEMS), are standard equipment in most road vehicles. Typically, such MEMS sensors are used to implement driver assistance system functionalities, such as airbag functionality, electronic stability control, or hill-hold assist. Other applications include navigation, typically in conjunction with a global navigation system (GNSS). In highly automated driving, MEMS sensors are used, for example, to perform emergency stops, in which the vehicle is brought to a controlled halt.

[0003] In the field, MEMS sensors are subject to certain disturbances in their output signals, particularly due to external influences such as changes in temperature and / or humidity, mechanical stress (e.g., bending of a circuit board on which the MEMS sensor is soldered), aging effects, linear and rotational accelerations or vibrations, and / or the coupling of electromagnetic interference in the environment or in the supply voltages. These influences represent disturbances and can cause changes in parameters such as offset, sensitivity, cross-axis sensitivity, or signal noise.

[0004] The known MEMS sensors are designed to compensate for such environmental influences within certain limits in order to enable the applications mentioned above. However, increasingly stringent requirements, particularly regarding the smallest possible size and reduced testing costs, pose challenges for their development. Disclosure of the invention

[0005] In this context, the invention aims to provide a method for operating a MEMS sensor which is suitable for compensating for interference occurring during the operation of the MEMS sensor.

[0006] The aforementioned problem is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are specified in the dependent claims.

[0007] According to one aspect of the invention, it is proposed to draw insights for development from field data that can be generated by MEMS sensors in use, in particular with regard to improved error correction and / or improved compensation of a disturbance variable that only occurs during operation.

[0008] Another aspect involves providing a MEMS sensor configured to implement a subsequently adapted compensation method. Such an adapted compensation method can be applied, in particular, as an update to MEMS sensors that are already in operation.

[0009] A MEMS sensor within the scope of this disclosure is a semiconductor device comprising a microelectromechanical system (MEMS) and an integrated circuit (ASIC) designed for device-specific control and evaluation of the MEMS. The microelectromechanical system includes a movable structure typically integrated within a layered structure of the MEMS sensor. To protect the movable structure, the MEMS sensor may optionally include a cap, which may also be formed within the layered structure of the semiconductor device. The microelectromechanical system represents a physical realization of a MEMS sensor; that is, the MEMS sensor can, in various embodiments, be, for example, a pressure sensor, an ultrasonic sensor, or, particularly preferably, an inertial sensor.

[0010] When operating such a MEMS sensor in the field, unprocessed raw sensor data is acquired, for example, as unprocessed analog sensor signals. Based on this unprocessed raw sensor data, processed initial sensor output data is generated according to a defined initial compensation rule. This initial compensation rule is determined by initial compensation parameters, which are determined, for example, at the end of a production line in a measurement and trimming step and stored in a non-volatile, and specifically non-rewritable, initial memory of the MEMS sensor. The initial sensor output data generated according to the initial compensation rule is made available in a first output register of the MEMS sensor for external transmission, particularly to an external control unit.In this way, it can be ensured, in particular, that the initial compensation rule defined by the initial compensation parameters meets the specified safety requirements. Especially for MEMS sensors intended for use in safety-critical applications in the automotive sector, such as in vehicle dynamics control systems and / or airbag systems, there are correspondingly high demands regarding sensor performance. To avoid retroactively invalidating the development process, which was carried out according to certain standards, and the extensively tested sensor performance of the MEMS sensor, the initial compensation parameters are stored in non-volatile primary memory, and the initial sensor output data is made available for external transmission according to these parameters.

[0011] After the MEMS sensor is put into operation in its intended application, for example to control a safety device in a motor vehicle, the first sensor output data are generated, in particular in accordance with the relevant safety requirements, according to the first compensation rule.

[0012] As explained at the outset, MEMS sensors are typically subject to a variety of interferences during operation. To compensate for interferences that arise subsequently and / or aging effects, it is proposed to update the operating procedure in a revision step. In this process, a second set of compensation parameters is transmitted from an external data processing system to the MEMS sensor (also called a download) and stored in a second memory of the MEMS sensor. A second compensation rule is then determined based on these second set of compensation parameters. This second compensation rule can, for example, correspond to a modified error correction and changed safety requirements.

[0013] The first and second memory locations can be configured as the first and second memory areas of a memory unit. Similarly, the first and second output registers can be configured as the first and second register areas of an output register.

[0014] During operation of the MEMS sensor, after an update of the operating procedure, second, cleaned sensor output data is generated based on the uncleaned raw sensor data, according to the second compensation rule. This second sensor output data is then made available in a second output register for external transmission, particularly to the external control unit. In this way, control can be carried out, especially after the update step, according to the adapted second sensor output data, particularly with modified disturbance compensation.

[0015] Preferably, the first sensor output data generated according to the first compensation rule are still made available in the first output register for external transmission, particularly to the external control unit, even after an update of the operating procedure of the MEMS sensor. This ensures, in particular, that the MEMS sensor continues to provide sensor output data generated according to specified certification and / or safety requirements, even after an update of the operating procedure. This data includes the first sensor output data generated according to the first compensation rule. For example, the basic functionality of a vehicle dynamics control system can continue to be maintained by the sensor output assigned to the first output register, while the second output register provides an additional sensor output for a novel application or compensation rule.

[0016] An updateable MEMS sensor according to the presented method, i.e., an updateable sensor in this sense, comprises at least one microcontroller and two separate data paths for generating the first and second sensor output data.

[0017] In advantageous embodiments, each data path is preferably assigned a microcontroller, a memory, and an output register. The microcontroller implements a compensation rule for generating clean sensor output data in the respective data path. The compensation rule for each data path is determined by compensation parameters stored in the respective assigned memory.

[0018] In a preferred embodiment, the MEMS sensor comprises - a first microcontroller for generating the cleaned first sensor output data based on the uncleaned sensor raw data according to the first compensation rule, - a first output register for the external provision of the first sensor output data, in particular to an external control unit and / or to an external data processing system, - a non-volatile first memory for the irreversible storage of the first compensation parameters that determine the first compensation rule, - a second microcontroller for generating cleaned second sensor output data based on the uncleaned sensor raw data according to the second compensation rule, - a second output register for external provision of the second sensor output data, - a second, in particular non-volatile, memory for storing the second compensation parameters that determine the second compensation rule.

[0019] The output registers each have external interfaces for transmitting sensor output data between the MEMS sensor and an external data processing system. The output registers also serve to transmit configuration data (download) containing the second compensation parameters during operating procedure updates. Data transmission can occur indirectly, in particular via an interposed control unit and / or a readout device, a base station (e.g., in a workshop), or similar equipment.

[0020] According to a preferred variant of the presented method, the first sensor output data is generated according to the first compensation rule using the first microcontroller of the MEMS sensor. In the update step, the second microcontroller of the MEMS sensor is initialized to generate the second sensor output data according to the second compensation rule.

[0021] In a preferred embodiment, the second memory is a one-time programmable (OTP) memory that is written to for the first time in the update step.

[0022] Preferably, the second compensation parameters are encrypted and transmitted to the MEMS sensor during the update step (download) and decrypted on the sensor side. The MEMS sensor preferably includes a cryptography module for encrypting and decrypting data stored or to be stored in the second output register. The cryptography module preferably assigns the MEMS sensor a unique identifier so that the MEMS sensor can be addressed individually, particularly during the update step.

[0023] Preferably, the MEMS sensor includes a radio module for wireless transmission, in particular via Bluetooth, of data stored or to be stored in the second output register. The radio module can be configured, in particular, for communication with a readout device via BLE (Bluetooth Low Energy). The readout device can be, for example, a smartphone, workshop device, readout station in a fleet operations center, roadside readout station (V2X), readout station in a private EV charging station, or similar.

[0024] In preferred embodiments, the first and / or second sensor output data comprise internal sensor parameters, which are transmitted in encrypted form from the MEMS sensor to the external data processing system (upload). In this way, sensor measurements can be collected and aggregated, describing, for example, the offset behavior at different temperatures. Internal sensor parameters include, for example, quadratures, phases, Q factors, mechanical frequencies and their differences, operating times, temperatures, offsets, noise, the number and occurrence times of fail flags, measurement series, stress sensor output, or similar data. The internal sensor parameters reflect, in particular, disturbances occurring during the operation of the MEMS sensor. This data is preferably used to develop improved compensation methods. The second compensation method is preferred.The second compensation parameters are determined, particularly by the external data processing system, taking into account the previously transmitted sensor parameters. Especially with widespread availability of such field data, numerous optimization opportunities arise in sensor development. It is also advantageous to react to new requirements relatively quickly. Possible features include event detection, navigation algorithms, customized filter settings, or artificial intelligence methods. If both upload and download capabilities are provided, it is also possible to create tailored features and compensations for an individual MEMS sensor, or to develop feature extensions or improvements for all MEMS sensors, particularly those within a vehicle fleet, using traditional or AI-generated methods.

[0025] The benefits and advantages described in connection with automotive applications also apply similarly, particularly to the field of consumer electronics. Further details and advantages of the invention are explained in more detail below with reference to the exemplary embodiments shown in the drawings. The drawings show: Fig. 1 a MEMS sensor according to a first embodiment of the invention; Fig. 2 a MEMS sensor according to a second embodiment of the invention; Fig. 3. A method for operating the MEMS sensor in a schematic block diagram.

[0026] Identical or corresponding elements are provided with the same reference symbols in all drawing figures.

[0027] Fig. 1 and Fig. Figure 2 shows possible designs of an updateable MEMS sensor 10, where the in Fig. 2. The embodiment shown includes an optional radio module 40.

[0028] The MEMS sensor 10 comprises a microelectromechanical system 20, which, for example, implements the sensor technology of an inertial sensor and can be designed, in particular, to detect rotation rates or linear accelerations. An integrated circuit 30 is provided for controlling the microelectromechanical system 20 and for evaluating the data provided by the microelectromechanical system 20. This circuit includes two separate data paths D1 and D2.

[0029] During operation of the MEMS sensor 10, the microelectromechanical system 20 generates analog sensor signals S, which are digitized into raw sensor data SR by means of an analog-to-digital converter 32. The integrated circuit 30 is designed to process the raw sensor data SR separately into sensor output data SA1 and SA2 in data paths D1 and D2. For this purpose, a first microcontroller 33 is assigned to the first data path D1. This microcontroller is designed to generate the first sensor output data SA1 based on the raw sensor data SR. The first sensor output data SA1 is generated according to a first compensation rule, which is determined by first compensation parameters KP1. To store the first compensation parameters KP1, a non-volatile memory 34, for example, an OTP memory, is assigned to the first data path D1 and the first microcontroller 33.Accordingly, a second microcontroller 36 is assigned to the second data path D2, which is designed to generate second sensor output data SA1 based on the raw sensor data SR. The second sensor output data SA1 is generated according to a second compensation rule, which is determined by second compensation parameters KP2. A second memory 37, for example an OTP memory, is assigned to the first data path D2 or the second microcontroller 36 for storing the second compensation parameters KP2.

[0030] In various configurations, the second memory 37 can be a volatile or non-volatile memory.

[0031] To provide the first sensor output data SA1, generated in the first data path D1, to an external control unit 100, the integrated circuit 30 includes a first output register 35. The integrated circuit 30 is further configured to provide the second sensor output data SA2, generated in the second data path D2, separately from the first sensor output data SA1, to the external control unit 100 in a second output register 39. Transmission to the external control unit 100 can be wired or wireless.

[0032] The sensor output data SA1, SA2 provided in the first and / or second output register 35, 39 can include internal sensor parameters SI1, SI2, such as quadratures, phases, Q factors, mechanical frequencies and their differences, operating time, temperatures, offsets, noise, number and time of occurrence of fail flags, measurement series, stress sensor output.

[0033] In the illustrated embodiments, the transmission of the internal sensor parameters SI2 is encrypted. The integrated circuit 30 includes a cryptography module 38 for encrypting and decrypting the data stored or to be stored in the second output register 39. In particular, data exchanged with an external data processing system 110 for updating an operating procedure can be transmitted via an encrypted data channel SC. In the embodiment of the Fig. 1. The MEMS sensor 10 is indirectly connected to the external data processing system 110 via the control unit 100, for example, of a driver assistance system, wherein the connection between the control unit 100 and the external data processing system 110 is established as a wireless connection. In the exemplary embodiment of the Fig. 2 The MEMS sensor 10 is indirectly connected to the external data processing system 110 via a readout device 105. The MEMS sensor 10 has a radio module 40 configured for communication with the readout device 105. The wireless connection between the MEMS sensor 10 and the external data processing system 110 can be provided, in particular, by means of a Bluetooth Low Energy interface.

[0034] Fig.Figure 3 illustrates a method for operating the MEMS sensor 10. During the manufacturing of the MEMS sensor 10, a first compensation rule, defined by first compensation parameters KP1, is determined for the first data path D1 in a manufacturing step F1 by means of measurement and trimming, and the first compensation parameters KP1 are stored in the first memory 34. In an optional further manufacturing step F2, further auxiliary values ​​are stored in the second memory 37 of the MEMS sensor 10. Further manufacturing steps F3 may include, in particular, packaging (tape and reel), transport and / or soldering of the MEMS sensors 10 onto printed circuit boards in the final product, and optionally conditioning or similar processes.

[0035] In step B1, the MEMS sensor 10 is put into operation. During operation of the MEMS sensor 10, first sensor output data, cleaned from the uncleaned sensor raw data SR, are generated according to the first compensation rule defined in manufacturing step F1 and made available in the first output register 35 for external transmission to the external control unit 100.

[0036] During operation, the mechanical and / or electrical properties of the MEMS sensor 10 can change, particularly due to aging effects, weathering, and / or other environmental influences such as temperature, humidity, and vibration. Such disturbances can be especially dependent on the specific positioning of the MEMS sensor 10 on a printed circuit board (PCB / PCB stress). As a result, the MEMS sensor 10 may no longer exhibit the desired performance, as, for example, offset and / or sensitivity errors and / or noise may be increased.

[0037] To compensate for the occurring disturbances, an update of the operating procedure of the MEMS sensor 10 is carried out in an update step A1.

[0038] To update the operating procedure, the control unit 100 or the radio interface 40 requests data relating to the sensor's internal parameters SI1 and SI2. A data package containing these parameters is compiled and encrypted using the cryptography module 38 with a unique identifier. This data package is then transmitted to the external data processing unit 100, which generates the second compensation rule or the second compensation parameters KP2 based on the transmitted data. When determining the second compensation rule or the second compensation parameters KP2, the auxiliary values ​​stored in the second output register 39 during manufacturing step F2 can be taken into account.Subsequently, the compensation formula in the second data path D2 is adjusted, whereby the second compensation parameters KP2 are transmitted in encrypted form from the external data processing system 110 to the MEMS sensor 10 and stored in the second memory 37. The second microcontroller 36 of the MEMS sensor 10 is then initialized, after resuming operation in step B2, to generate second sensor output data SA2 according to the second compensation formula, which is made available for external transmission via the second output register 39. The second sensor output data SA2 provided in the sensor output of the second output register 39 can, in particular, correspond to a modified offset and / or sensitivity error correction and / or noise reduction with preferably increased sensor performance.The first sensor output data SA1 generated according to the first compensation rule are still made available in the first output register 35 for external transmission to the external control unit 100 after the update.

[0039] The proposed method is characterized, firstly, by the fact that sensor-internal parameters SI1 and SI2 are made available for upload and used to generate a modified compensation formula. Secondly, a download and sensor-side implementation of new features is proposed.

[0040] The invention is not limited to the embodiments described above, but can be used for a variety of inertial sensor-based applications for navigation, orientation, and stabilization of objects. A processing unit within the sensor can be used to control the operation of the inertial sensor (e.g., power-saving mode, measuring ranges), to check the plausibility of sensor signals and their tolerances (e.g., for internal sensor monitoring), to perform signal processing (e.g., calculating position or orientation, filtering data), and to select communication protocols. Various algorithms, including self-learning AI-based algorithms, can be used in the processing unit for evaluating and processing the data from the inertial sensors, temperature sensors, and also external data (e.g., GPS data, odometer data).It is also conceivable that the application could be used in the following areas: two-wheeled vehicles such as motorcycles, bicycles, and scooters (e.g., ESP / airbag, tilt detection); three-wheeled vehicles (e.g., tuk-tuks); avionics applications (e.g., flight stabilization and control); industrial robot applications (e.g., controlling the position of excavator buckets, image stabilization, flight control, satellite antenna alignment, fine motor skills for robot grasping); home and garden applications (e.g., lawnmower navigation, door position monitoring); medical applications (e.g., fall detection, motion and posture recognition); sports and leisure activities (e.g., motion detection, posture recognition in golf clubs, tennis rackets, and skis); and numerous consumer electronics applications (e.g., in smartphones, tablets, wearables, hearing aids, drones, and toys).

[0041] Furthermore, the invention can be used in connection with smartphones and tablets for the following applications: screen orientation; detection of significant movements; device orientation; activity, gesture, and context recognition; image stabilization; indoor SLAM (simultaneous localization and mapping); impact and free-fall detection; motion control. In the context of wearables, hearables, AR (augmented reality), and VR (virtual reality), the invention can be used for the following applications: displaying information; step counting; activity, gesture, and context recognition; calorie counting; in-ear detection; sleep monitoring; elderly care; indoor navigation; position determination; low-power sensing; real-time motion detection; head tracking; precise sensor data fusion.In connection with drones, games, and toys, the invention can be used for the following applications: orientation; gimbal suspension; altitude stabilization; flight control; motion tracking; motion control; balancing; activity and gesture recognition. In connection with robots, the invention can be used for the following applications: navigation; boundary detection; dynamic path planning; indoor SLAM; air quality monitoring; blockage detection. In the context of smart homes, the invention can be used for the following applications: burglary control; air quality monitoring; mold detection; climate control; floor level detection; indoor navigation. The invention can also be used in an industrial context for the following applications: water level sensing; asset tracking; navigation and control; motion and position tracking; energy management; predictive maintenance.Furthermore, numerous modifications, variations, designs, arrangements and embodiments are possible, all of which fall within the scope of the invention.

Claims

[1] Method for operating a MEMS sensor (10), wherein uncleaned sensor raw data (SR) are generated during the operation of the MEMS sensor (10), wherein, prior to updating an operating procedure, cleaned first sensor output data (SA1) are generated based on the uncleaned sensor raw data (SR) according to a defined first compensation rule, wherein the first sensor output data (SA1) are made available in a first output register (35) for external transmission, in particular to an external control unit (100), wherein the first compensation rule is determined based on first compensation parameters (KP1) which are stored in a non-volatile first memory (34) of the MEMS sensor (10), wherein in an update step (A1) of the operating procedure second compensation parameters (KP2) are transmitted from an external data processing system (110) to the MEMS sensor (10) and stored in a second memory (37) of the MEMS sensor (10), wherein a second compensation rule is determined on the basis of the second compensation parameters (KP), wherein, during the operation of the MEMS sensor (10), after updating the operating procedure based on the uncleaned sensor raw data (SR), second sensor output data (SA2) are generated according to the second compensation rule, wherein the second sensor output data (SA2) are made available in a second output register (39) for external transmission, in particular to the external control unit (100). [2] Method according to claim 1, wherein first sensor output data (SA1) generated according to the first compensation rule are further made available in the first output register (35) for external transmission, in particular to the external control unit (100), during the operation of the MEMS sensor (10) after updating the operating procedure. [3] Method according to claim 1 or 2, wherein the second memory (37) is a once writable OTP memory which is written for the first time in the update step (A1). [4] Method according to one of the preceding claims, wherein the second compensation parameters (KP2) are transmitted encrypted to the MEMS sensor (10) in the update step (A1) and decrypted on the sensor side. [5] Method according to one of the preceding claims, wherein the generation of the first sensor output data (SA1) according to the first compensation rule is carried out by means of a first microcontroller (33) of the MEMS sensor (10) and in the update step a second microcontroller (36) of the MEMS sensor (10) is initialized to generate the second sensor output data (SA2) according to the second compensation rule. [6] Method according to one of the preceding claims, wherein the second compensation parameters (KP2) transmitted in the update step (A1) are transmitted wirelessly to the MEMS sensor (10). [7] Method according to one of the preceding claims, wherein the first and / or second sensor output data (SA1, SA2) comprise internal sensor parameters (SI1, SI2) which are transmitted in encrypted form from the MEMS sensor (10) to the external data processing system (110). [8] MEMS sensor (10) which is configured to be operated according to a method of the preceding claims. [9] MEMS sensor (10) according to claim 8, comprising a first microcontroller (33) for generating cleaned first sensor output data (SA1) from uncleaned sensor raw data (SR) according to a first compensation rule, a first output register (35) for externally providing the first sensor output data (SA1), a non-volatile first memory (34) for storing first compensation parameters (KP1) determining the first compensation rule, a second microcontroller (36) for generating cleaned second sensor output data (SA2) from the uncleaned sensor raw data (SR) according to a second compensation rule, a second output register (39) for externally providing the second sensor output data (SA2), and a second memory (37) for storing the second compensation parameters (KP2) determining the second compensation rule. [10] MEMS sensor according to claim 8 or 9, comprising a cryptography module (38) for encrypting and decrypting data stored or to be stored in the second output register (39), in particular data containing the second compensation parameters (KP2). [11] MEMS sensor according to one of the preceding claims, comprising a radio module (40) for wireless external transmission of data stored or to be stored in the second output register (39), in particular data containing the second compensation parameters (KP2).

Images