A bluetooth-based wireless absolute value encoder

Abstract

This utility model relates to the field of encoder technology, specifically to a Bluetooth-based wireless absolute encoder. The encoder includes a gyroscope, a first CPU, a ferroelectric memory, a power management module, a second CPU, and an interface chip. The first CPU is a low-power chip with Bluetooth transceiver functionality. The first CPU is connected to the gyroscope to read and process gyroscope data and transmit it via Bluetooth. The ferroelectric memory is connected to the first CPU and stores calibration parameters and encoder data, enabling power-off data retention. The power management module provides a stable voltage to each IC through a regulated LDO. The second CPU is the same low-power Bluetooth wireless chip as the first CPU, responsible for receiving Bluetooth signals from the first CPU. The interface chip is connected to the second CPU via a serial port to send the received data to the relevant interface. This utility model solves the technical problems of low lifespan and low accuracy caused by using idler wheels to mount encoders in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of encoder technology, specifically to a Bluetooth-based wireless absolute encoder. Background Technology

[0002] Encoders are widely used in crane safety monitoring. For ease of installation, encoders with idlers are commonly used. Their main function is to calculate the travel of the trolley and crane or the height of the hook. Encoders are divided into two types: incremental encoders and absolute encoders. Incremental encoders output pulses and do not have a memory function. Their advantages are low price and high cost-effectiveness, but their disadvantages are susceptibility to interference and lack of memory.

[0003] Whether it's an incremental encoder or an absolute encoder, an idler wheel is needed for quick and easy installation. Idler wheel installation has the following disadvantages: 1) The rotation of the idler wheel causes wear, shortening its service life; 2) The idler wheel cannot function properly when the track is curved, and it is prone to falling and being damaged due to track bending; 3) Pulse-type incremental encoders are susceptible to motor current noise and encoder frequency interference, resulting in low accuracy. Utility Model Content

[0004] This invention provides a Bluetooth-based wireless absolute encoder to solve the technical problems of low service life and low accuracy caused by encoders mounted with idlers in the prior art.

[0005] To solve the above problems, the Bluetooth-based wireless absolute encoder provided by this utility model adopts the following technical solution:

[0006] A Bluetooth-based wireless absolute encoder includes a gyroscope, a first CPU, a ferroelectric memory, a power management module, a second CPU, and an interface chip. The gyroscope is mounted beside the center of a wheel to measure its rotation angle. The first CPU is a low-power chip with Bluetooth transceiver functionality. The first CPU is connected to the gyroscope to read and process gyroscope data and transmit it via Bluetooth. The ferroelectric memory is connected to the first CPU and stores calibration parameters and encoder data, enabling power-off data retention. The power management module provides a stable voltage to each IC through a regulated LDO.

[0007] The second CPU is the same low-power Bluetooth wireless chip as the first CPU, which is responsible for receiving Bluetooth signals from the first CPU. The interface chip is connected to the second CPU via a serial port to send the received data to the relevant interface for further analysis.

[0008] Furthermore, the gyroscope is a low-power three-axis gyroscope LSM6DS3TR-C, the first CPU is a low-power NRF52832-QFAA-R, and the first CPU communicates with the gyroscope via SPI four-wire communication, namely SPI 0_MOSI, SPI 0_MISO, SPI 0_CS and SPI 0_CLK. The INT1 and INT2 pins of the gyroscope are programmable outputs used to indicate whether data is ready, and are connected to the CPU to trigger data reading.

[0009] Furthermore, the ferroelectric memory is an 8KBytes ferroelectric memory, which is connected to the first CPU via two-wire TWD communication and is used to store calibration parameters and encoder data.

[0010] Furthermore, the power management module is powered by a lithium battery, and the regulated LDO converts the 3.6V lithium battery voltage to a stable 3.3V to power all ICs, achieving low power consumption and long battery life.

[0011] Furthermore, the interface chip is a MAX485ECMM / TR, which is used to convert the Bluetooth signal received by the second CPU from the first CPU into an RS485 signal. The relevant interface is an RS485 interface to output the RS485 signal for further analysis.

[0012] Furthermore, in the first CPU, VCC_BAT is the external battery input, VCC is the regulated power supply, which provides the working voltage for the chip and peripheral circuits, and capacitors C28 (100nF) and C33 (100nF) are filter capacitors to filter out power supply noise and ensure stable power supply.

[0013] The reset circuit consists of resistor R2 (10kΩ) and capacitor C34 (100nF). The capacitor charges upon power-up to achieve a reset, or the system can be manually triggered to initialize.

[0014] Furthermore, in the ferroelectric memory, A0-A2 (address pins) are all grounded (GND) for I2C / TWD bus multi-device differentiation; VSS is grounded, SDA (data line) is connected to the TWD / SDA pin of the main control chip for bidirectional data transmission; SCL (clock line) is connected to the TWD / SCL pin of the main control chip, with the main control providing the clock synchronization signal; WP (write protection) is grounded (GND) to disable write protection; VDD (power supply) is connected to 3.3V (powered by LDO regulation) to provide the operating voltage for the chip.

[0015] C43 (100nF) is connected in parallel between VDD and VSS to filter out power supply noise; R30 and R31 (10kΩ) are connected between SDA, SCL and VCC respectively to realize the wired-AND function of the I2C / TWD bus; the main control CPU interacts through the TWD (I2C compatible) bus, and the main control can write calibration parameters and forward / reverse degrees through the SCL clock and SDA data pins.

[0016] Furthermore, in the gyroscope, VDD (pin 8) is connected to 3.3V (powered by LDO regulation) as the main power supply, VDDIO (pin 6) is connected to 3.3V, and GND (pins 5 and 7) is grounded as the negative terminal of the circuit.

[0017] INT1 (pin 4) and INT2 (pin 9) are connected to the main control interrupt pins to trigger the main control to read data;

[0018] C22 (100nF) is connected in parallel between VDDIO and GND to filter out digital power supply noise and ensure stable SPI communication;

[0019] C23 (100nF) is connected in parallel between VDD and GND to filter out analog power supply noise and improve the gyroscope acquisition accuracy.

[0020] The SPI bus directly interfaces with the SPI interface of the main control chip, without the need for additional level conversion;

[0021] INT1 can be configured as an angular velocity data ready signal. After the main controller detects an interrupt, it reads the latest angular velocity value via SPI.

[0022] Furthermore, in the regulated LDO, the VIN (pin 3) input voltage is connected to VCC_BAT to provide power to the chip;

[0023] The EN (pin 4) enable pin, when connected to VIN (active high), initiates the conversion.

[0024] GND (pin 5) is grounded and is the negative terminal of the circuit;

[0025] The EP (pin 7) pad is exposed for grounding and heat dissipation;

[0026] SW (pin 1) is the switching node. When the internal MOSFET switch is working, the voltage is reduced through the inductor and capacitor.

[0027] VOUT (pin 2) is the output voltage feedback terminal, which is connected to the feedback resistors (R6, R7) to determine the output voltage value;

[0028] FB (pin 6) is the feedback pin, which is connected to the midpoint of the voltage divider resistors (R6, R7) to detect the output voltage and realize voltage regulation closed-loop control;

[0029] C41 (10uF) is connected in parallel between VCC_BAT and GND to filter out high-frequency noise in the input voltage and ensure stable chip input.

[0030] Furthermore, it also includes a battery input and overcurrent protection circuit. In this circuit, BAT_IN is the input interface for the lithium battery, which is connected to an external battery; F1 is a fuse connected in series between the positive terminal of the battery and the system power supply VCC_BAT. When the circuit current is too high, the fuse blows, cutting off the power supply and protecting the subsequent circuits; VCC_BAT is the system power network, which outputs power to the step-down circuit and other modules.

[0031] The beneficial effects of the Bluetooth-based wireless absolute encoder provided by this utility model are: 1) It uses a low-power gyroscope to detect the position or height of the crane's trolley and crane; 2) It uses Bluetooth to wirelessly receive encoder signals. A ferroelectric memory is installed at the wireless sensor end to store the encoder's forward and reverse rotation degrees and calibration parameters, thus achieving power-off data retention; 3) It eliminates the need for an idler mechanism, greatly increasing its service life; 4) By using a gyroscope to implement the encoder function, it is unaffected by on-site current noise, greatly enhancing its anti-interference capability. Accuracy is significantly improved. Attached Figure Description

[0032] The above and other objects, features, and advantages of the present invention will become readily understood by reading the following detailed description of exemplary embodiments with reference to the accompanying drawings. In the drawings, several embodiments of the present invention are shown by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0033] Figure 1 This is a block diagram of the wireless absolute encoder provided by this utility model;

[0034] Figure 2 A schematic diagram showing the wireless absolute encoder provided by this utility model installed on a wheel;

[0035] Figure 3 This is a block diagram of the Bluetooth receiver of the second CPU in this utility model;

[0036] Figure 4 A schematic diagram illustrating the use of three wireless absolute encoders;

[0037] Figure 5 This is a circuit diagram of the first CPU in this utility model;

[0038] Figure 6 This is the circuit diagram of the ferroelectric memory in this utility model;

[0039] Figure 7 This is the circuit diagram of the gyroscope in this utility model;

[0040] Figure 8 This is the circuit diagram of the voltage-regulating LDO in this utility model;

[0041] Figure 9 This is the overcurrent protection circuit diagram of this utility model.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Wireless absolute encoder; 2. Wheel; 3. Wireless receiver. Detailed Implementation

[0044] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Those skilled in the art should understand that the embodiments described below are only some, not all, of the embodiments disclosed. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0045] The principles and spirit of this utility model will be explained in detail below with reference to several representative embodiments.

[0046] An embodiment of the Bluetooth-based wireless absolute encoder provided by this utility model:

[0047] like Figures 1 to 9 As shown, the Bluetooth-based wireless absolute encoder includes a gyroscope, a first CPU, a ferroelectric memory, a power management module, a second CPU, and an interface chip. The gyroscope is mounted next to the center of the wheel to measure the wheel's rotation angle. The first CPU is a low-power chip with Bluetooth transceiver functionality. The first CPU connects to the gyroscope to read and process gyroscope data and transmit it via Bluetooth. The ferroelectric memory is connected to the first CPU and is used to store calibration parameters and encoder data, enabling power-off data retention. The power management module provides a stable voltage to each IC through a regulated LDO.

[0048] The second CPU is the same low-power Bluetooth wireless chip as the first CPU, responsible for receiving Bluetooth signals from the first CPU. The interface chip is connected to the second CPU via a serial port to send the received data to the relevant interface for further analysis.

[0049] The gyroscope is a low-power three-axis gyroscope LSM6DS3TR-C, and the first CPU is a low-power NRF52832-QFAA-R. The first CPU communicates with the gyroscope via SPI four-wire communication, namely SPI 0_MOSI, SPI 0_MISO, SPI 0_CS and SPI 0_CLK. The gyroscope's INT1 and INT2 pins are programmable outputs used to indicate whether data is ready, and are connected to the CPU to trigger data reading.

[0050] In this embodiment, the power management module is powered by a lithium battery. The voltage of the 3.6V lithium battery is converted to a stable 3.3V through the voltage regulator LDO to power all ICs and achieve low power consumption and long battery life.

[0051] like Figure 2 As shown, the entire encoder is installed in the center area of ​​the wheel, as... Figure 3 As shown, in crane safety monitoring applications, a trolley with two hooks is a common structure, and the detection positions for the trolley travel and the height of the two hooks are relatively close. The design uses one receiver to receive signals from three wireless absolute encoders (wireless trolley travel, wireless main hook height, and wireless auxiliary hook height), and cleverly utilizes a low-power gyroscope to detect the position or height of the crane trolley and main hook, eliminating the need for an idler wheel mechanism and greatly increasing service life.

[0052] The interface chip is MAX485ECMM / TR. The interface chip is used to convert the Bluetooth signal received by the second CPU from the first CPU into an RS485 signal. The relevant interface is an RS485 interface to output the RS485 signal for further analysis.

[0053] like Figure 5 As shown, in the first CPU, VCC_BAT is the external battery input, VCC is the regulated power supply, which provides the working voltage for the chip and peripheral circuits, and capacitors C28 (100nF) and C33 (100nF) are filter capacitors to filter out power supply noise and ensure stable power supply.

[0054] The reset circuit consists of resistor R2 (10kΩ) and capacitor C34 (100nF). The capacitor charges upon power-up to achieve a reset, or the system can be manually triggered to initialize.

[0055] The crystal oscillator X1 (32.768kHz), capacitor C25 (12pF), and capacitor C29 (100pF) form a low-speed clock circuit, which provides the basic clock for low-power operation of the chip and is connected to the X1 and X2 pins.

[0056] The crystal oscillator X2 (32MHz), capacitors C26 (12pF) and C27 (12pF) form a high-speed clock circuit, which provides a high-frequency clock for Bluetooth communication, data processing, etc., and is connected to the XC1 and XC2 pins.

[0057] MOSI (P0.01), MISO (P0.08), SCK (P0.02), and SPID_CS (P0.29) are SPI bus pins used to connect to a gyroscope to achieve high-speed data transmission.

[0058] SDA (P0.27) and SCL (P0.26) are TWD bus pins used to connect to ferroelectric memory and transmit non-volatile data such as calibration parameters and forward / reverse degrees.

[0059] RXD (P0.05) and TXD (P0.06) are UART serial port pins;

[0060] L1 (1.8nH), L3 (6.2nH), and C31 (1pF) form a matching circuit, which is connected to the ANT pin to optimize RF signal transmission.

[0061] SWDIO (P0.28) and SWCLK (P0.25) are serial debug interface pins. Together with a debugger (H1 and D2, etc., form a debug circuit), they enable program downloading and online debugging.

[0062] The LED indicator (LED1) is connected to pin P0.03 and current is limited by resistor R39 (4.7kΩ). It can be used to indicate the device status.

[0063] like Figure 6 As shown, the ferroelectric memory is an 8KBytes ferroelectric memory, which is connected to the first CPU using two-wire TWD communication and is used to store calibration parameters and encoder data.

[0064] In the ferroelectric memory, A0-A2 (address pins) are all grounded (GND) for I2C / TWD bus multi-device differentiation; VSS is grounded, SDA (data line) is connected to the TWD / SDA pin of the main control chip for bidirectional data transmission; SCL (clock line) is connected to the TWD / SCL pin of the main control chip, with the main control providing the clock synchronization signal; WP (write protection) is grounded (GND) to disable write protection; VDD (power supply) is connected to 3.3V (powered by LDO regulation) to provide the chip's operating voltage.

[0065] C43 (100nF) is connected in parallel between VDD and VSS to filter out power supply noise; R30 and R31 (10kΩ) are connected between SDA, SCL and VCC respectively to realize the wired-AND function of the I2C / TWD bus; the main control CPU interacts through the TWD (I2C compatible) bus, and the main control can write calibration parameters and forward / reverse degrees through the SCL clock and SDA data pins.

[0066] like Figure 7 As shown, in the gyroscope, VDD (pin 8) is connected to 3.3V (powered by LDO regulation) as the main power supply, VDDIO (pin 6) is connected to 3.3V, and GND (pins 5 and 7) is grounded as the negative terminal of the circuit; INT1 (pin 4) and INT2 (pin 9) are connected to the main control interrupt pin to trigger the main control to read data; C22 (100nF) is connected in parallel between VDDIO and GND to filter out digital power supply noise and ensure stable SPI communication; C23 (100nF) is connected in parallel between VDD and GND to filter out analog power supply noise and improve the gyroscope's acquisition accuracy; the SPI bus directly interfaces with the SPI interface of the main control chip without additional level conversion; INT1 can be configured as an angular velocity data ready signal. After the main control detects an interrupt, it reads the latest angular velocity value through SPI.

[0067] In addition, regarding the data flow, the gyroscope collects angular velocity → transmits it to the main control chip (NRF52832) via the SPI bus (SDO / SA0 → SPI 0_MISO; SDx → SPI 0_MOSI; SCLK → SPI 0_CLK; CS → SPI 0_CS) → the main control chip converts it into "wheel rotation angle / stroke" → and sends it to the gateway via Bluetooth.

[0068] like Figure 8 As shown, in the voltage-regulated LDO, VIN (pin 3) is the input voltage, connected to VCC_BAT, providing power to the chip; EN (pin 4) is the enable pin, connected to VIN (active high) to initiate the conversion upon power-up; GND (pin 5) is grounded, serving as the circuit's negative terminal; EP (pin 7) is an exposed pad for grounding and heat dissipation; SW (pin 1) is the switching node, where the internal MOSFET switch reduces the voltage through an inductor and capacitor; VOUT (pin 2) is the output voltage feedback terminal, connected to feedback resistors (R6, R7) to determine the output voltage value; FB (pin 6) is the feedback pin, connected to the midpoint of the voltage divider resistors (R6, R7) to detect the output voltage and achieve closed-loop voltage regulation control; C41 (10uF) is connected in parallel between VCC_BAT and GND to filter out high-frequency noise in the input voltage, ensuring stable chip input.

[0069] like Figure 9As shown, it also includes a battery input and overcurrent protection circuit. In this circuit, BAT_IN is the input interface of the lithium battery, which is connected to an external battery; F1 is a fuse, which is connected in series between the positive terminal of the battery and the system power supply VCC_BAT. When the circuit current is too large, the fuse blows, cutting off the power supply and protecting the subsequent circuits; VCC_BAT is the system power network, which outputs power to the step-down circuit and other modules.

[0070] The working principle of the Bluetooth-based wireless absolute encoder provided by this utility model is as follows: An LSM6DS3TR-C3 axis gyroscope installed near the wheel or drum outputs real-time angular velocity data as the wheel or drum rotates, replacing the traditional mechanical contact structure. A first CPU reads this data via the SPI bus, combines it with wheel diameter, drum parameters, etc., to calculate the corresponding travel or height, and stores key data such as forward / reverse direction, calibration parameters, and position before power failure in a ferroelectric memory MB85RC64TAPNF (ferroelectric memory supports unlimited writes and does not lose data when power is lost). Then, the NRF52832 utilizes the Bluetooth Low Energy (BLE) of the second CPU... The calculated travel or height data is wirelessly sent to the gateway; the NRF52832 on the gateway receives and parses the Bluetooth signal, and then converts the data into an RS485 bus signal through the MAX485 chip, which is then transmitted to the crane safety monitoring system to realize real-time display of information such as trolley position and hook height, as well as overtravel judgment; the sensor end is powered by a 3.6V lithium battery regulated to 3.3V by a TPS62122 to power the gyroscope, Bluetooth CPU, and ferroelectric storage, ensuring low power consumption and long battery life; the gateway end is directly powered by the cabinet power supply. The entire process solves the pain points of traditional encoders in a non-mechanical contact, wireless transmission manner, and realizes accurate and stable detection and safety monitoring of crane travel and height.

Claims

1. A Bluetooth-based wireless absolute value encoder, characterized by: The system includes a gyroscope, a first CPU, a ferroelectric memory, a power management module, a second CPU, and an interface chip. The gyroscope is mounted beside the center of the wheel to measure its rotation angle. The first CPU is a low-power chip with Bluetooth transceiver functionality. The first CPU is connected to the gyroscope to read and process gyroscope data and transmit it via Bluetooth. The ferroelectric memory is connected to the first CPU and is used to store calibration parameters and encoder data, enabling power-off data retention. The power management module provides a stable voltage to each IC through a regulated LDO. The second CPU is the same low-power Bluetooth wireless chip as the first CPU, which is responsible for receiving Bluetooth signals from the first CPU. The interface chip is connected to the second CPU via a serial port to send the received data to the relevant interface for further analysis.

2. The Bluetooth-based wireless absolute value encoder of claim 1, wherein: The gyroscope is a low-power three-axis gyroscope LSM6DS3TR-C, and the first CPU is a low-power NRF52832-QFAA-R. The first CPU and the gyroscope communicate via SPI four-wire communication, namely SPI0_MOSI, SPI0_MISO, SPI0_CS and SPI0_CLK. The INT1 and INT2 pins of the gyroscope are programmable outputs used to indicate whether data is ready and are connected to the CPU to trigger data reading.

3. The Bluetooth-based wireless absolute value encoder of claim 2, wherein: The ferroelectric memory is an 8KBytes ferroelectric memory, which is connected to the first CPU via two-wire TWD communication and is used to store calibration parameters and encoder data.

4. The Bluetooth-based wireless absolute value encoder of claim 3, wherein: The power management module is powered by a lithium battery. The voltage of the 3.6V lithium battery is converted to a stable 3.3V through the voltage regulator LDO to power all ICs and achieve low power consumption and long battery life.

5. The Bluetooth-based wireless absolute value encoder of claim 4, wherein: The interface chip is MAX485ECMM / TR. The interface chip is used to convert the Bluetooth signal received by the second CPU from the first CPU into an RS485 signal. The relevant interface is an RS485 interface to output the RS485 signal for further analysis.

6. The Bluetooth-based wireless absolute value encoder of claim 5, wherein: In the first CPU, VCC_BAT is the external battery input, VCC is the regulated power supply, which provides the working voltage for the chip and peripheral circuits, and capacitors C28 and C33 are filter capacitors to filter out power supply noise and ensure stable power supply. Resistor R2 and capacitor C34 form a reset circuit. When the power is on, the capacitor charges to achieve a reset. The reset can also be triggered manually to initialize the system.

7. The Bluetooth-based wireless absolute encoder according to claim 6, characterized in that: In the ferroelectric memory, A0-A2 are all grounded for I2C / TWD bus multi-device differentiation; VSS is grounded, SDA is connected to the TWD / SDA pin of the main control chip for bidirectional data transmission; SCL is connected to the TWD / SCL pin of the main control chip, and the main control provides the clock synchronization signal; WP is grounded to disable write protection; VDD is connected to 3.3V to provide the operating voltage for the chip. C43 is connected in parallel between VDD and VSS to filter out power supply noise; R30 and R31 are connected between SDA, SCL and VCC respectively to realize the wired-AND function of the I2C / TWD bus; it interacts with the main control CPU through the TWD bus, and the main control can write calibration parameters and forward / reverse degrees through the SCL clock and SDA data pins.

8. The Bluetooth-based wireless absolute value encoder of claim 7, wherein: In the gyroscope, VDD is connected to 3.3V and serves as the main power supply; VDDIO is connected to 3.3V; and GND is grounded and serves as the negative terminal of the circuit. INT1 and INT2 are connected to the main controller interrupt pins to trigger the main controller to read data; C22 is connected in parallel between VDDIO and GND to filter out digital power supply noise and ensure stable SPI communication. C23 is connected in parallel between VDD and GND to filter out analog power supply noise and improve the gyroscope acquisition accuracy; The SPI bus directly interfaces with the SPI interface of the main control chip, without the need for additional level conversion; INT1 can be configured as an angular velocity data ready signal. After the main controller detects an interrupt, it reads the latest angular velocity value via SPI.

9. The Bluetooth-based wireless absolute value encoder of claim 8, wherein: In a regulated LDO, the VIN input voltage is connected to VCC_BAT to provide power to the chip; The EN enable pin, when connected to VIN, initiates the conversion. GND is grounded and is the negative terminal of the circuit. EP exposed pads for grounding and heat dissipation; SW is the switching node. When the internal MOSFET switch is working, the voltage is reduced through inductors and capacitors. VOUT is the output voltage feedback terminal, which is connected to the feedback resistor and determines the output voltage value. FB is the feedback pin, which is connected to the midpoint of the voltage divider resistor to detect the output voltage and realize voltage regulation closed-loop control; C41 is connected in parallel between VCC_BAT and GND to filter out high-frequency noise in the input voltage and ensure stable chip input.

10. The Bluetooth-based wireless absolute value encoder of claim 9, wherein: It also includes a battery input and overcurrent protection circuit. In this circuit, BAT_IN is the input interface for the lithium battery, which is connected to an external battery; F1 is a fuse connected in series between the positive terminal of the battery and the system power supply VCC_BAT. When the circuit current is too high, the fuse blows, cutting off the power supply and protecting the downstream circuit; VCC_BAT is the system power network.

Images