Sensor hub

Abstract

The present invention relates to a sensor hub (3) open platform, as part of a servo motor assembly, including at least one communication interface (8) for communicating with at least one sensor (4), a computing device for evaluating and / or processing and / or converting data acquired from at least one sensor, and a communication interface (7) for communicating with at least a master device (1).

Description

Technical Field

[0001] This invention relates to the field of servo motor assemblies, and more particularly to sensor hubs as open platforms for connecting any possible type of sensor to a known type of connection between a position sensor and a master device, as part of a servo motor assembly. Background Technology

[0002] EP 3 462 138 A1 (Rockwell Automation) "Board mounted microelectromechanical system (MEMS) sensors for motor diagnostics and analytics" describes a method for providing motor diagnostics and analysis. However, it is limited to describing the sensors used and their location within the servo motor, without describing the communication with the host computer.

[0003] Another solution for providing vibration data acquired within a servo motor is described in SICK's product information document, "EDS / EDM35, sHub Motor Feedback System Rotary HIPERFACEDSL®" (part number: 8023528). This document describes a condition monitoring system where a vibration sensor is placed close to the encoder and uses the Hiperface DSL protocol as the encoder to communicate with a general-purpose host (in this case, the motor drive). The drawback of this solution is that this closed architecture only allows for specific encoders and specific sensors. The number of external sensors is limited to two. It cannot be scaled up to meet the requirements of individual system solutions. Summary of the Invention

[0004] The purpose of this invention is to provide a sensor hub as part of an open platform and servo motor assembly for operating a flexible combination of different types of sensors, using existing cabling and having a small footprint, which allows for integration within existing machines and / or provides a very compact and easy system integration in space-constrained applications.

[0005] Embodiments of the present invention provide a sensor hub in the form of a computing device, which connects one or more sensors to acquire, process, or convert sensor data, and connects to a host device that requests and processes the sensor data. The host device may be a standalone device or may be integrated into a position sensor control device or motor driver of a servo motor assembly. Preferably, a single cable is used to connect the host device and the sensor hub.

[0006] In some embodiments of the invention, communication signals from the sensor hub to the main device are preferably transmitted and modulated over the power supply voltage line. In principle, digital data can be transmitted using any known modulation method, such as amplitude, frequency, or phase modulation of the carrier frequency.

[0007] In some embodiments of the present invention, a communication method such as that described in patent EP 3 439 245 B1 is used.

[0008] In some embodiments of the invention, the sensor hub can be implemented within existing cable infrastructure, which is highly advantageous for expanding the condition monitoring and predictive maintenance capabilities of existing machines (i.e. retrofitted machines). Preferably, communication is achieved by using existing power lines to minimize the workload of cable routing, connectors, footprint, and system complexity, allowing any type of sensor to be attached to or near the attached sensor hub device, such as in or around a motor, gearbox, or machine near the motor.

[0009] In some embodiments of the invention, the sensor hub communicates with the host device using an RS485 interface or other similar communication standards to maximize bandwidth and minimize cost by using standard RS485 line drivers and standard microcontrollers. This device has a very small footprint, providing flexibility in installation location and thus enabling various installation locations of the sensor hub and attached sensors within or near the point of interest. High-temperature ranges are achievable using standard line drivers and standard microcontrollers compared to FPGA-based solutions. Power line modulation is preferably implemented using passive electronic components. A wide input power range is achieved through appropriate switching regulators.

[0010] In a preferred embodiment of the invention, the communication protocol described in EP 3 439 245 B1 is used for communication between the sensor hub and the master device. This communication protocol advantageously supports real-time requirements. Data acquired by the sensors can be synchronized to simplify data processing and analysis. For example, vibration sensor data acquired from the sensor hub can be easily synchronized with position data from a feedback sensor or encoder attached in parallel to the sensor hub on the same wire.

[0011] This concept allows for synchronization to the motor control cycle in a single hybrid cable solution, where switching insulated-gate bipolar transistors (IGBTs) causes noise spikes on the communication wires. Therefore, communication can be achieved during the noise-free time interval between two IGBT switching events to avoid communication errors.

[0012] Advantages of the present invention

[0013] The servo motor's feedback encoder is powered via a power supply line and communicates with the host device (e.g., the motor controller) via an encoder data line. The power supply voltage is always present at any point on the servo motor assembly. The sensor hub preferably communicates with the host device via the encoder's common voltage supply line. The sensor hub's data signal is modulated onto the voltage supply line and can be received from the host device.

[0014] Any type of sensor can be connected to a sensor hub. For this purpose, a sensor hub provides several digital and / or analog standard interfaces for connecting sensors. The sensor hub converts sensor signals into a protocol used for communication with the host device, and preferably transmits the signals to the host device by modulating the data signals onto the power line.

[0015] Embodiments of the present invention advantageously provide a method for monitoring the condition of motors, gears, and machines and performing predictive maintenance by using a single-cable solution and a flexible, open architecture, minimizing installation work and costs, maximizing flexibility in using a variety of numbers and types of sensors, and enabling the integration of systems with high bandwidth and real-time capabilities.

[0016] Various embodiments of the present invention provide flexible combinations of different types of sensors, utilizing existing cabling and having a small footprint. This allows for integration within existing machines (retrofitted machines) or provides very compact and easy system integration in space-constrained applications (e.g., robotics). They allow for simultaneous real-time data acquisition from multiple sensors, enabling additional use cases and increasing the value of the acquired data. The computing power within the sensor hub and main unit allows edge computing to pre-evaluate the acquired data to perform condition monitoring and predictive maintenance tasks. The main unit can also connect to internal or internet-based cloud applications to enable broader network connectivity, such as computing condition monitoring or predictive maintenance algorithms, and communication with other connected devices (e.g., PLCs, etc.). The host can also be integrated into a motor drive to increase system integration density. Attached Figure Description

[0017] Preferred embodiments of the invention are illustrated in the accompanying drawings, thereby producing further inventive features. The illustrated embodiments are not intended to be limiting, but rather examples of various possible embodiments of the invention.

[0018] Figure 1 A schematic diagram of a sensor hub embedded in a servo motor assembly according to a first embodiment of the present invention is shown.

[0019] Figure 2 A schematic diagram of a sensor hub in an embedded servo motor assembly according to a second embodiment of the present invention is shown.

[0020] Figure 3 A schematic diagram of a sensor hub in an embedded servo motor assembly according to a third embodiment of the present invention is shown.

[0021] Figure 4 A schematic diagram of a sensor hub in an embedded servo motor assembly according to a fourth embodiment of the present invention is shown.

[0022] Figure 5 A schematic diagram of a sensor hub in an embedded servo motor assembly according to a fifth embodiment of the present invention is shown.

[0023] Figure 6 A schematic diagram of a sensor hub embedded on a printed circuit board of a servo motor assembly is shown. Detailed Implementation

[0024] Figure 1 A preferred embodiment of the invention is shown, wherein the sensor hub 3 is used as a condition monitoring system that communicates with the main device 1 using existing sensor cables 6.

[0025] The main unit 1 and sensor hub 3 communicate via existing power lines 6a provided by the servo motor driver 2 to power the servo motor feedback encoder 5 of the servo motor 9. Sensor hub 3 is connected to power lines 6a via a communication interface 7. Communication between sensor hub 3 and main unit 1 is modulated via these power lines 6a without interfering with the function of the servo motor feedback system. Motor 9 is powered by the servo motor driver 2 via a separate motor power cable 10. Gearbox 11 is attached to motor 9.

[0026] The servo motor feedback encoder 5 communicates with the servo motor driver 2 via a separate encoder data line 6b, which is part of the sensor cable 6. At least one sensor 4 (e.g., a vibration sensor) is connected to the sensor hub 3 via an interface 8 (e.g., I2C, SPI, UART, or an analog interface). Additional sensors 4 for measuring temperature, torque, position, radar, humidity, etc., can be connected to the sensor hub 3. The master device 1 requests sensor data from the sensor hub 3 and, in some embodiments, can be used as an edge device to perform condition monitoring and predictive maintenance calculations, and can also connect to a device-based or internet-based cloud application 25. Using this solution, a condition monitoring system can be easily implemented on existing machines using existing cables and connectors.

[0027] Figure 2 A preferred embodiment of the invention is shown, wherein the sensor hub 3 serves as a protocol converter for sensor data from connected sensors 4 and 13 and data from the second encoder 12. The basic configuration is similar. Figure 1 .

[0028] Sensor hub 3 is connected in parallel with motor feedback encoder 5 via communication interface 7, and both communicate with master device 1 via sensor cable 6 upon request. Second encoder 12 and torque sensor 13 are attached to motor and / or gearbox 11, and both connect to sensor hub 3 using existing technology protocols (e.g., BiSS, SSI) or providing analog signals (e.g., A, B, Z). Upon request from master device 1, sensor hub 3 acquires data from second encoder 12 and sensor 13 (which may be a torque sensor), synchronizing with the request from first motor feedback encoder 5. Sensors 4, 13 and second encoder 12 can be connected to sensor hub, for example, via I2C, SPI, UART interfaces or analog interfaces, and sensor hub 3 converts data from different sensors 4 and 13 and second encoder 12 into a protocol for communication between sensor hub 3 and master device 1. This can be the RS485 protocol or communication protocol described in EP 3 439 245 B1. Multiple standard sensors 4 and 13 can be connected to a single-cable system via sensor hub 3. The main device 1 can be an external device or can be integrated into the servo motor driver 2.

[0029] Figure 3 A preferred embodiment of the invention is shown, wherein the sensor hub 3 is used for condition monitoring of multiple sensors or diagnostic systems.

[0030] Multiple sensors, such as encoder 5, motor winding temperature sensor 16, sensor 4 (which may be a vibration sensor), and sensor 13 (which may be a vibration and shock sensor), as well as a motor brake diagnostic system 18 for motor brake 15, are connected to sensor hub 3 via known interfaces such as I2C, SPI, UART, or analog interfaces. Sensors 4, 5, 16, 13, and 18 are located at motor 9 and / or motor brake 15 and / or gearbox 11. Sensor hub 3 converts data received from the different sensors 4, 5, 16, 13, and 18 into a protocol for communication between sensor hub 3 and host device 1. Sensor hub 3 is directly connected to host device 1 via a single hybrid cable 14 through communication interface 7. Hybrid cable 14 includes sensor cable 6 for data transmission and motor power cable 10 from servo motor driver 2 to motor 9. Host device 1 can be integrated within servo motor driver 2 or can be placed independently and connected to a machine network and / or a device-based or Internet-based cloud application 25. This invention achieves high data bandwidth, which allows for real-time motor control based on multiple encoders, temperature data, and torque data to optimize overall machine efficiency.

[0031] Figure 4A preferred embodiment of the invention is shown, wherein the sensor hub 3 is used to establish synchronous multi-encoder communication with the master device 1.

[0032] The sensor hub 3 allows for system setup using multiple encoders 5, 12 and sensor 13, where sensor 13 can be a torque sensor connected to the sensor hub 3. The sensor hub 3 is connected to the sensor cable 6 via a communication interface 7, enabling the transmission of position data from the first encoder 5 and the second encoder 12, as well as data from sensor 13 or a third encoder, to the master unit 1 within a single motor control cycle. Fast data transmission, low overhead, and dual-channel data allow for absolutely safe position detection.

[0033] Figure 5 A preferred embodiment of the invention is shown, wherein the sensor hub 3 is used for sensor fusion.

[0034] Sensor hub 3 connects to multiple encoders 5 and 12 and allows system setup using encoders 5 and 12 to enable data transmission of position data between a first encoder 5 placed on the drive shaft and a second encoder 12 placed on the load shaft of gearbox 11. The position data of both encoders 5 and 12 are simultaneously latched via sensor hub 3. Sensor hub 3 is directly connected to sensor cable 6 via communication interface 7. Sensor hub 3 and / or main unit 1 can calculate torque values ​​based on the difference between the received position data of encoders 5 and 12, and can detect anomalies to provide condition monitoring or predictive maintenance information.

[0035] Figure 6 A schematic diagram of a sensor hub embedded on a printed circuit board 19 of a servo motor assembly is shown. The printed circuit board 19 is, for example, ring-shaped, to be embedded on the back or front of the servo motor. On the printed circuit board are the electronic components 20 of the sensor hub, including a computing device 26 in the form of a microcontroller unit (MCU), a (flexible) connector 21 for connecting a vibration sensor 4, additional connectors 22, 23 for connecting various sensors and encoders to the sensor hub, and electronic components 24 forming a communication interface for communicating with a host device via power lines or data lines.

[0036] List of reference numerals

[0037] 1. Main Unit

[0038] 2 Servo motor drivers

[0039] 3 Sensor Hub

[0040] 4 sensors

[0041] 5. Motor feedback encoder

[0042] 6. Sensor cable

[0043] 7. Communication Interface

[0044] 8 Sensor Interface

[0045] 9 motors

[0046] 10. Electric motor power cables

[0047] 11 Gearbox

[0048] 12 Second Encoder

[0049] 13 Sensors

[0050] 14 Hybrid Cable

[0051] 15. Motor brake

[0052] 16 Temperature Sensors

[0053] 18. Diagnosis of motor brake

[0054] 19 Printed Circuit Boards

[0055] 20 Electronic components (for modulation / demodulation)

[0056] 21 Flexible electrical connectors

[0057] 22 Connector for connecting the original encoder cable

[0058] 23 Second connector for connecting the feedback encoder

[0059] 24 Electronic Components

[0060] 25 External Applications

[0061] 26. Computing device

Claims

1. A sensor hub (3) open platform, as part of a servo motor assembly, comprising: At least one sensor communication interface (8) for communicating with at least one sensor (4, 13, 16). A computing device (26) for processing data acquired from the at least one sensor (4, 13, 16), and A communication interface (7) for communicating with at least the main device (1), wherein the sensor hub (3) and the main device (1) are connected by a single cable (6, 14); The feature is that the communication interface (7) connected to the main device (1) is designed to enable real-time transmission of position data of the first encoder (5) and real-time transmission of position data of the second encoder (12) or data of additional sensors (4, 13) within a single motor control cycle; and wherein the sensor communication interface (8) is designed to enable synchronous data acquisition of at least one sensor (4, 13, 16) and at least one encoder (5, 12).

2. The sensor hub (3) open platform according to claim 1, characterized in that, The computing device (26) is used to evaluate data acquired from the at least one sensor (4, 13, 16).

3. The sensor hub (3) open platform according to claim 1, characterized in that, The computing device (26) is used to convert data acquired from the at least one sensor (4, 13, 16).

4. The sensor hub (3) open platform according to claim 1, characterized in that, The sensor hub (3) is connected to the first encoder (5) via the communication interface (7).

5. The sensor hub (3) open platform according to claim 1, characterized in that, The communication interface (7) connected to the main device (1) is designed to provide communication over the power cable (6a) via a modulation method.

6. The sensor hub (3) open platform according to claim 5, characterized in that, The modulation method includes amplitude, frequency, or phase modulation of the carrier frequency.

7. The sensor hub (3) open platform according to claim 1, characterized in that, The communication interface (7) connected to the main device (1) is an RS485 interface.

8. The open platform of the sensor hub (3) according to claim 1, characterized in that, At least one sensor (4, 13, 16) connected to the sensor hub (3) includes one of the following sensors: vibration sensor, position sensor, torque sensor, temperature sensor.

9. The sensor hub (3) open platform according to claim 1, characterized in that, The main device (1) is a standalone device or integrated into the position sensor control device or motor driver (2) of the servo motor assembly.

10. The sensor hub (3) open platform according to claim 1, characterized in that, The sensor hub (3) is designed to be retrofitted into the servo motor assembly and connected to the cable (6, 14).

Images