Self-contained multi-dimensional measurement radar sensor

Abstract

A radar sensor for detecting the level of a filling material or the topology of a filling material surface, comprising a clock of the permanent running type which closes the power supply line to the processor at a predetermined time to activate the processor. The processor then controls a switching device to activate the radar chip.

Description

Technical Field

[0001] This invention relates to radar measurement technology. In particular, it relates to radar sensors for detecting the level of filling material or the surface topology of filling material, various uses of such radar sensors, methods for detecting the level of filling material or the surface topology of filling material, program elements, and computer-readable media. Background Technology

[0002] In process automation within industrial environments, particularly for level measurement, multidimensional (i.e., two-dimensional or three-dimensional) measurement radar systems can be used. These radar sensors typically require external power sources to operate, and the energy demands can be substantial. Summary of the Invention

[0003] In this context, the object of the present invention is to provide an alternative radar sensor.

[0004] A first aspect of the invention relates to a radar sensor configured and programmed to detect the level of a filler material and / or the surface topology of the filler material. Specifically, the radar sensor may be configured for process automation in an industrial environment and includes a persistent clock, an energy storage device, computing circuitry such as a processor (possibly combined with an FPGA), one or more radar circuits or radar chips, and at least a first switching device.

[0005] Specifically, the persistent clock is configured to control a first switching device at a predetermined time to close a power line, thereby supplying power from the energy storage to the computing circuitry and activating it. The computing circuitry is configured and programmed to control the first switching device after its activation to close (another) power line, thereby supplying energy from the energy storage to the radar chip required for level and / or topology detection.

[0006] In the context of this invention, the terms “switching device,” “power line,” and “computing circuit” should be interpreted broadly.

[0007] The term "process automation in industrial environments" can be understood as a subfield of technology encompassing all measures for operating machines and equipment without human intervention. One goal of process automation is to automate the interaction of various components within a plant in industries such as chemical, food, pharmaceutical, petroleum, paper, cement, shipping, or mining. To this end, a large number of sensors are used, particularly suited to the specific requirements of process industries, such as mechanical stability, insensitivity to contaminants, extreme temperatures, and extreme pressures. These sensor measurements are typically transmitted to a control room where process parameters such as level, limit levels, flow rate, pressure, or density are monitored, and settings throughout the plant can be changed manually or automatically.

[0008] One subfield of process automation in industrial environments involves logistics automation. In logistics automation, processes inside or outside buildings, or within individual logistics devices, are automated using distance and angle sensors. Typical applications include logistics automation systems for areas such as airport baggage and cargo handling, traffic monitoring (toll collection systems), trade, parcel delivery, and building security (access control). A common thread in the examples listed above is the need to combine presence detection with precise measurements of object size and location. For this purpose, sensors based on optical measurement methods, such as lasers, LEDs, 2D cameras, or 3D cameras, can be used. These sensors detect distance based on the time-of-flight (ToF) principle.

[0009] Another subfield of process automation in industrial environments involves factory / manufacturing automation. Examples of this application can be found in many industries, such as automotive manufacturing, food manufacturing, pharmaceuticals, or general packaging. The goal of factory automation is to automate the production of goods performed by machines, production lines, and / or robots—that is, to operate without human intervention. The sensors used here, and the specific requirements for measurement accuracy in detecting the position and size of the objects, are comparable to those in the aforementioned examples of logistics automation.

[0010] According to one embodiment, the radar sensor includes a second switching device, wherein the computing circuit is configured to control the second switching device to close a control line after its activation, so as to send a control signal from the computing circuit to the radar chip.

[0011] According to another embodiment, the radar sensor includes a third switching device, wherein the computing circuit is configured to control the third switching device after its activation in order to send measurement data from the radar chip to the computing circuit.

[0012] According to another embodiment, the radar sensor includes a wireless communication module, wherein computing circuitry is configured to control a first switching device to close a power line after its activation, so as to provide the energy required for the operation of the wireless communication module from an energy storage device to the wireless communication module.

[0013] According to another embodiment, the radar sensor has a sealed housing that has no external electrical interface. Therefore, this radar sensor is, in particular, a self-contained radar sensor with its own internal power supply.

[0014] According to another embodiment, the radar sensor includes another energy storage device and a fourth switching device. In this case, a clock is configured to control the first switching device at a predetermined time to close the power line between the first energy storage device and the other energy storage device, so as to first charge the other energy storage device with energy from the first energy storage device. Thereafter, the fourth switching device is controlled to provide energy from the first energy storage device and the other energy storage device to the computing circuit, thereby activating the computing circuit.

[0015] Another aspect of the present invention relates to the use of the radar sensors described above and below as microwave gratings and / or for area monitoring of machine safety areas.

[0016] In the above applications, the step of "detecting the level of the filling material or the topology of the filling material surface" can be omitted. Alternatively, "determining the switching signal" can be provided. The corresponding methods are known to those skilled in the art.

[0017] Another aspect of the present invention relates to a method for detecting the level of a filling material and / or the topology of the filling material surface. The method includes the following steps: controlling a first switching device to close a power line at a predetermined time via an internal clock of the device to supply power from an internal energy storage unit to a computing circuit, thereby activating the computing circuit; and controlling the first switching device to close the power line via the computing circuit to supply energy from the energy storage unit to a radar chip required for level and / or topology detection.

[0018] Another aspect of the invention relates to a program element that, when executed on the computing circuitry of the radar sensor described above and below, instructs the radar sensor to perform the steps described above and below.

[0019] Another aspect of the present invention relates to a computer-readable medium storing the aforementioned program elements. Attached Figure Description

[0020] Embodiments of the present invention will now be described with reference to the accompanying drawings. The illustrations in the drawings are schematic and not drawn to scale. If the same reference numerals are used in the following description of the drawings, these reference numerals denote the same or similar elements.

[0021] Figure 1 A radar sensor according to one embodiment is shown.

[0022] Figure 2 A flowchart of a method according to one embodiment is shown.

[0023] Figure 3 A radar sensor according to another embodiment is shown.

[0024] Figure 4 A flowchart according to another embodiment is shown. Detailed Implementation

[0025] Figure 1 A multidimensional (i.e., two-dimensional or three-dimensional) measurement radar sensor 100 is shown, which can be specifically configured and programmed for process automation or factory automation in industrial environments. For example, the radar sensor can be configured (but not limited to) a three-dimensional measurement radar system (topology detection radar system) for measuring loose material piles, but it can also be configured as a multidimensional measurement microwave grating. In particular, the radar sensor can be designed as a self-contained radar sensor, i.e., requiring no external power supply.

[0026] Due to the existing system architecture, the multidimensional measurement sensors known to date are extremely power-intensive. Furthermore, the transmission of measurement results in multidimensional measurement radar systems has so far been achieved via wired connections, resulting in a significant workload for equipment installation and maintenance.

[0027] The basic idea and embodiments of the present invention eliminate the aforementioned disadvantages. In particular, a multidimensional measurement radar system (hereinafter also referred to as a radar sensor) for factory automation, logistics automation, or process automation is proposed. This multidimensional measurement radar system obtains all the energy required for its operation from at least one energy source (e.g., a battery) integrated in the device, and is further designed to provide determined measurement values ​​and / or values ​​derived from the measurement values ​​to the outside using wireless communication technology.

[0028] The self-contained one-dimensional measurement radar system 100 can be used specifically in the fields of process automation, factory automation, or safety technology to determine the distance to an object and provide that distance to the outside via a 2-wire interface (4.20mA), a 3-wire interface (IO-Link), or a wireless interface 112.

[0029] Furthermore, it opens up the possibility of using the multi-dimensional measurement radar system 100 in the field of automation. The basis of this possibility is the radar system on chip (RSoC), which provides a large number of hardware components for realizing multiple transmit channels and multiple receive channels of radar signals. These hardware components include the necessary digital control circuitry on a single chip.

[0030] The multidimensional measurement radar sensor 100 can also be used to measure containers in stationary production equipment. Other applications of this measuring device can be found, particularly in logistics or decentralized measurement scenarios (e.g., monitoring river levels). The core idea here is to configure the radar sensor to determine measurements completely autonomously and wirelessly relay those measurements to an upstream communication network.

[0031] In the field of wireless communication, this technology has developed rapidly in recent years, especially leading to new narrowband radio technologies for energy-efficient IoT devices. The drawback of these technologies is that they can only transmit a limited number of user data bytes.

[0032] However, there have been no significant improvements in energy-saving solutions for integrated radar-on-a-chip (RSoC). Since these components were primarily developed for use in the automotive sector, there will be no fundamental improvement in energy consumption in the coming years.

[0033] Figure 1 The self-contained multidimensional radar sensor 100 shown obtains all the energy required for its operation entirely from the energy storage device 102 (e.g., battery 102) integrated in the device.

[0034] A persistent real-time clock (RTC) 103 is fixedly connected to the energy storage unit 102. The processor 104 can parameterize the RTC 103 via a communication line (not shown). When the previously parameterized activation time is reached, the RTC 103 generates a logic switch signal at its output 105. This logic switch signal can be used to control and close a switching element 106, which is part of the first switching devices 106, 109 and may be, for example, a semiconductor transistor 106. Upon this closure, the battery 102 is connected to the processor 104 via power line 129 to activate the processor 104, which then reads and executes program code from the non-volatile memory 107. Specifically, the processor 104 now takes over control of the switch 106, thereby taking over the self-holding function via line 108. During program execution, the processor 104 can activate individual components via power switch 109, i.e., apply a power supply voltage to them. Specifically, voltage can be applied here to the first radar chip 110 via power line 130, to the second radar chip 111 via power line 131, and / or to the wireless communication module 112 (e.g., LPWAN module 112) via power line 132. For parameterization and / or control purposes, at least one control line 117, 118, 128 between the processor 104 and units 110, 111, 112 can be additionally connected via control switch 113 and then disconnected again. Thus, it is particularly effective to prevent units 110, 111, 112 from drawing undefined lateral currents from the processor via control lines during periods of no voltage supply, which could adversely affect power consumption. For exactly the same reason, the data lines 114 and 115 used to transmit data from radar chips 110 and 111 to processor 104 during active measurement can be disconnected from the processor via data line switch 116 during deactivation.

[0035] It should be noted here that, Figure 1All the switching devices 109, 113, and 116 shown can have a large number of individual switching elements by which a large number of physically necessary electrical wiring connections can be closed and / or disconnected, the number of which depends on the respective signal technology. Thus, control lines 117 and 118 can be, for example, SPI, QSPI, or IIC technologies, and may include, for example, transmission lines, receive lines, chip select lines, and / or clock lines. In practice, the illustration of a single line 117 or 118 may imply the insertion of multiple wires in a manner known to those skilled in the art. Corresponding considerations also apply to signal lines 114 and 115. It should also be noted that “closing” a switching element within switches 109, 113, and 116 may mean establishing an electrical connection, or it may also mean activating a control circuit or level shifter. Furthermore, “opening” a switching element within switches 109, 113, and 116 may mean disconnecting an electrical connection, or it may also mean disabling a control circuit or level shifter, or it may also mean switching to a high-ohm state. In this way, undefined lateral currents that negatively impact energy consumption can be prevented from flowing from the activated component 104 to the deactivated components 110 and 111.

[0036] This device provides a first radar chip 110 and a second radar chip 111 for implementing a multidimensional measurement radar system. These radar chips are connected to a processor 104 via data lines 114 and 115. The processor 104, specifically developed to match the radar modules 110 and 111, has a dedicated data line interface, such as a synchronous high-speed interface like LVDS or CSI-2. Furthermore, the processor 104 has a dedicated computing unit capable of efficiently and quickly processing the program steps of multidimensional radar measurements. It should be noted that the device 101 can also be operated using more or fewer radar chips 110 and 111.

[0037] Since the entire device 101 has no electrical interfaces for external use, in one embodiment all components belonging to the device 101 can be arranged within the sealed housing 177 to ensure maximum protection against external influences.

[0038] Figure 2A flowchart for operating device 101 is shown. The method begins from initial state 201. In step 202, RTC 103 checks if a new alarm time has been reached. If so, processor 104 is activated by closing switch 106, and processor 104 loads and executes a software program from non-volatile memory 107. In step 203, the processor activates a self-holding circuit via line 108 and programs the next alarm time for real-time clock 105 via a communication line (not shown here). In step 204, radar chips 110 and 111 are powered by closing the corresponding power switches 109. Then, in step 205, control lines 117 and 118 of radar chips 110 and 111 are connected to processor 104 via appropriate control commands. For this purpose, a portion of control line switch 113 is closed. Now, by additionally closing data line switch 116 in step 206, the RSoC is finally connected to processor 104. In step 207, the processor can transition the radar chip to an operational-ready state by transmitting a suitable control sequence via control lines 117 and 118. In this case, initialization and parameterization commands are specifically passed to the radar chip. In this case, lines 117 and 118 are specifically connected to a synchronous serial interface, such as an SPI or QSPI interface. Then, in step 208, the radar chip is controlled to perform measurements using at least one active high-frequency transmitter and an active high-frequency receiver. Data detected by RSoC 110 and 111 during this measurement is transmitted to the processor 104, for example, via data lines 114 and 115, and stored in memory disposed within or outside the processor. In step 209, the radar chip is first de-connected to the processor 104 by disconnecting switches 113 and 116 associated with lines 117, 118, 114, and 115, thereby initiating the shutdown of the radar chip. The processor controls switches 113 and 116 via corresponding signals, for example, via GPIO pins. In step 210, further unnecessary power consumption of the RSoCs 110 and 111 is completely prevented by opening the associated power switch 109 initiated by the processor. In step 211, according to known method steps, a measurement value is determined within the processor 104 using a dedicated computing unit based on the detected data. To enable the measurement value to be provided wirelessly, the power switch 109 of the radio unit 112 is closed in step 212, and the control line switch 113 to the radio unit is closed in step 213. In step 214, the determined measurement value is transmitted to the outside via the radio unit 112. It may be advantageous, but is by no means limiting, to use low-power wireless standards (LPWAN) such as LoRa, NB-IoT, or Sigfox. However, other wireless standards may also be used to transmit measurement and status values.In step 215, switches 109 and 113 are disconnected again, thereby disabling radio module 112. In step 216, processor 104 disables the self-holding circuit, causing switch 106 to open and the entire device 101 to transition to the off state. After the next parameterized alarm time in real-time clock 103 has elapsed, the above method is restarted.

[0039] A key aspect of the invention is the complete shutdown of device 101 between measurements, thereby maximizing energy savings. Another element of the invention is activating the components for the shortest possible time and then de-energizing them as quickly as possible. Furthermore, it may be advantageous to use a dedicated processor 104, which can efficiently and energy-efficiently handle the computational tasks according to the invention, thereby further saving energy and maximizing the lifespan of battery 102.

[0040] The proposed exemplary embodiment allows for the construction of a simple multi-channel radar system with a maximum of two radar chips. Further increasing the number of radar chips yields even better measurement results. Figure 3 Another exemplary embodiment according to the present invention is shown, the principle of which can also be applied to a system 301 with a large number of RSoCs. The same reference numerals denote... Figure 1 The same or similar parts.

[0041] The improved multidimensional measurement radar system 301 includes another radar chip 302, and... Figure 1 Compared to the previous example, this radar chip can improve the imaging characteristics of the device, especially its spatial resolution. Since the parallel operation of numerous radar chips 110, 111, and 302 can cause large current spikes on the chip's power lines, the following provision is made: after the alarm time of RTC 103 is reached, switch 106 is first closed via a state machine fixed in the programmable logic module 305, causing energy to be replenished to the intermediate memory 303 (e.g., capacitor 303 or battery 303). Specifically, replenished energy from the energy harvesting module 308 can also be used for this purpose. After reaching a fully charged state, logic 305 closes switch 304, which leads to the activation of the low-power processor 306 used. Figure 1 Compared to the exemplary embodiments described above, this processor is specifically optimized for maximum energy efficiency and, in particular, does not have dedicated interfaces and computing units for interacting with RSoCs 110, 111, and 302. The reading and processing of RSoC signals are performed in a dedicated hardware unit 307 (e.g., ASIC 307 or FPGA 307) for this purpose.

[0042] FPGA 307 is used to address the specific requirements of evaluating a large number of RSoCs 110, 111, and 302 when building multi-dimensional radar, as well as the computational architecture required for the evaluation steps of effectively computing radar signals. In this case, a classic SRAM-based FPGA can be used, which must be reconfigured using a binary programming sequence (bitstream) after being arbitrarily connected to the power supply voltage 310 externally via control line 311 (e.g., a synchronous control line 311 such as SPI or QSPI). However, an integrated SRAM-based FPGA with flash memory integrated in the housing can also be used. In this case, it may not be necessary to configure the FPGA via control line 311, as the corresponding pre-programmed FPGA automatically loads configuration data directly from the flash memory after being connected to the operating voltage 310. In a particularly advantageous embodiment, non-volatile FPGA technology 307 can also be provided. These are built based on flash memory technology, and a particular advantage provided in the context of this invention is that the configured bitstream logic is not lost again after a configuration is performed at the factory or during the first commissioning. Therefore, rewriting the binary programming sequence (bitstream) during operation can be omitted.

[0043] Figure 4A flowchart for operating device 301 is shown. The method begins in initial state 401. In step 402, RTC 103 checks if a new alarm time has been reached. If a new alarm time has been reached, in step 403, switch 106 is closed by means of logic 305, and the energy storage unit 303 is charged with energy from battery 102 and / or energy harvesting module 308 (photovoltaic module, thermocouple, wind turbine, etc.). After reaching a fully charged state, logic module 305 closes switch 304 in step 404 and activates processor 306. In step 405, the processor loads its program sequence logic from non-volatile memory element 107, parameterizes the next alarm time for RTC 103, and activates the self-holding circuit. Then, in step 406, the processor controls the power switch 109 of radar chips 110, 111, and 302. In step 407, by appropriately controlling control switch 113, the sequence logic of processor 306 connects the control lines 117, 118, and 312 of the radar chips to the synchronous serial interface of processor 306, such as the SPI or QSPI interface of processor 306. In step 408, by transmitting appropriate control commands, radar chips 110, 111, and 302 are initialized, configured, and switched to a ready state. Before actual measurements can begin, in step 409, FPGA 307 is first activated via switch 109, and then FPGA 307 is connected to the processor via control line switch 113. In this example, it is assumed that FPGA 307 is a flash-based FPGA, so no further initialization is required. Otherwise, the FPGA can now be initialized by transmitting a bitstream file via processor 306. In step 410, data lines 114, 115, and 309 (e.g., LVDS lines or CSI-2 lines of the radar chips) are connected to the FPGA. In step 411, processor 306 controls the radar chip to perform measurements and transmits the determined data to the FPGA. In step 412, processor 306 disconnects radar chips 110, 111, and 302 by opening corresponding switches 113 and 116, and powers them down by opening power switch 109. By applying a corresponding command via control line 311 (e.g., SPI line 311), the processor initiates the determination of one or more measurement values ​​in FPGA 307 in step 413. This is configured via highly specialized hardware modules to perform the calculation efficiently. In step 414, after disconnecting control line 311 by means of switch 109 and before powering down FPGA 307, the calculation result is transmitted to processor 306 via control line 311. In step 416, radio unit 112 is activated by closing switch 109, and the radio unit 112 is connected to the processor by closing the relevant switching element 113.Before powering down the radio module 112 again by disconnecting switches 113 and 109 in step 418, the measured values ​​are wirelessly provided to an external system in step 417. In step 419, processor 306 disables the self-holding circuit, causing logic 305 to disconnect switches 304 and 106 and the entire device 301 to transition to the off state. The above method restarts after the next parameterized alarm time in real-time clock 103 has elapsed.

[0044] It is important to note that the processor 306 can be integrated with the FPGA to form a system-on-a-chip. The processor can also be implemented as a soft-core processor within the FPGA's programming logic.

[0045] The computing unit can also be integrated into the RSoC. Therefore, radar signals can be preprocessed.

[0046] Systems 101 and 301 can be activated in a time-controlled manner via RTC 103. Activation can also be made dependent on external environmental factors such as vibration or available energy.

[0047] It should also be noted that “shutting down” a module or component can also mean “disabling” it to reduce the required power.

[0048] It should also be noted that switching element 113 can also be integrated into processors 104 and 306. Switching element 116 can also be integrated or implemented in FPGA 307. FPGAs can also be supplemented with additional external memory.

[0049] The core idea of ​​this invention is to provide multiple power domains in the radar system, each with a different activation duration. Alternatively, it can be viewed as combining dedicated hardware modules that interact within the system due to their structure and / or their respective tasks, thereby achieving an energy-efficient system overall. In this way, the energy storage unit 102 can be kept relatively small. Furthermore, minimal energy is consumed per measurement cycle, maximizing battery life within the battery's existing maximum energy budget.

[0050] It should also be noted that "comprising" or "having" does not exclude other elements or steps, and "a" or "an" does not exclude multiple. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of the other above embodiments. Reference numerals in the claims should not be construed as limiting.

Claims

1. A radar sensor (100) for detecting the level of a filling material or the topology of the surface of a filling material, comprising: Persistent running clock (103); Energy storage device (102); Calculation circuits (104, 307); Radar chips (110, 111); First switching device (106, 109); and Wireless communication module (112), The clock is configured to control the first switching device to close the first power line (129) at a predetermined alarm time, so as to supply power from the energy storage device to the computing circuit, thereby activating the computing circuit. The computing circuit is configured to program the next alarm time of the clock after the first power line has been closed, and upon its activation, control the first switching device to close the second power line (130, 131) to supply the energy required for detecting the level or topology from the energy storage device to the radar chip. The computing circuit (104, 307) is configured to control the first switching device (106, 109) to close the third power line (128) after its activation, so as to supply the energy required for the operation of the wireless communication module from the energy storage device (102).

2. The radar sensor (100) according to claim 1, further comprising: Second switching device (113), The computing circuits (104, 307) are configured to control the second switching device to close the control lines (117, 118) after their activation, so as to send the control signals from the computing circuits (104, 307) to the radar chip (110, 111).

3. The radar sensor (100) according to claim 1 or 2, further comprising: The third switching device (116), The computing circuits (104, 307) are configured to control the third switching device after their activation, so as to send measurement data from the radar chip (110, 111) to the computing circuits (104, 307).

4. The radar sensor (100) according to claim 1 or 2, further comprising: The sealed housing (177) does not have an electrical interface for external use.

5. The radar sensor (100) according to claim 1 or 2, further comprising: Another energy storage device (303); and Fourth switching device (304), The clock (103) is configured to control the first switching device (106, 109) at a predetermined time to close the first power line (129) so as to first charge the other energy storage device with the energy storage device (102), and then control the fourth switching device to supply power from the energy storage device (102) and the other energy storage device (303) to the computing circuit (104, 307) to activate the computing circuit.

6. The use of the radar sensor (100) according to any of the preceding claims as a microwave grating or for area monitoring of machine safety areas.

7. A method for detecting the level of a filler material or the topology of the filler material surface, comprising the following steps: The device controls the first switching device to close the first power line (129) at a predetermined alarm time by the device's internal clock (103) so as to supply power from the device's internal energy storage unit (102) to the computing circuit (104, 307), thereby activating the computing circuit; After the first power line has been closed, the next alarm time of the clock is programmed by the computing circuit; The computing circuit controls the first switching device to close the second power line (130, 131) so as to supply the energy required to detect the level or the topology from the energy storage device to the radar chip; as well as The computing circuit controls the first switching device to close the third power line (128) so as to supply the energy required for the operation of the wireless communication module from the energy storage device to the wireless communication module.

8. A computer-readable medium storing program elements that, when run on a computing circuit (104, 307) of a radar sensor (100), instruct the radar sensor to perform the following steps: The device controls the first switching device to close the first power line (129) at a predetermined alarm time by the device's internal clock (103) so as to supply power from the device's internal energy storage unit (102) to the computing circuit (104, 307), thereby activating the computing circuit; After the first power line has been closed, the next alarm time of the clock is programmed by the computing circuit; The computing circuit controls the first switching device to close the second power line (130, 131) so as to supply the energy required for detecting level or topology from the energy storage device to the radar chip; as well as The computing circuit controls the first switching device to close the third power line (128) so as to supply the energy required for the operation of the wireless communication module from the energy storage device to the wireless communication module.

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