Accelerometer test circuit system

Abstract

The invention relates to the technical field of accelerometer testing, in particular to an accelerometer testing circuit system which comprises logic switches, an MCU processor, a conversion circuit and a power consumption resistor, each accelerometer is connected with the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch, the logic switches are connected with the MCU processor, and the MCU processor is connected with the conversion circuit and the power consumption resistor. The MCU processor controls the logic switch to gate the accelerometer and the conversion circuit or gate the accelerometer and the power consumption resistor; the conversion circuit is connected with the MCU processor, when the accelerometer is communicated with the conversion circuit, the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal, and the conversion circuit sends the frequency signal to the MCU processor. The test result is high in reliability, damage caused by no load of the output end of the accelerometer which is not tested can be avoided, and the test circuit system is small in size, light in weight and convenient to transfer and move.

Description

Technical Field

[0001] The present invention relates to the technical field of accelerometer testing, and in particular to an accelerometer testing circuit system. Background Art

[0002] Accelerometers play a vital role in inertial measurement units. Accelerometers can provide continuous motion information of the carrier. The degradation of accelerometer performance during use will directly affect the accuracy of the system. One of the main factors affecting accelerometer performance is insufficient stress release. If the accelerometer is equipped with "residual stress", stress release during use will cause changes in the main indicators of the accelerometer, resulting in reduced system accuracy and even affecting the success or failure of the mission. Based on this, it is necessary to design an accurate, efficient and simple test device.

[0003] Chinese patent CN117929789A discloses a quartz flexible accelerometer test device, which uses a series model of a high-precision digital multimeter + sampling resistor to test the accelerometer. The high-precision multimeter causes the overall volume of the test equipment to be large, making the test equipment difficult to turn around and not suitable for use under multiple working conditions. The test results are also determined by the high-precision multimeter and the test resistor. Therefore, any failure or reduced accuracy of the device will lead to unreliable test results, resulting in invalid tests. Moreover, although the accelerometer test device can measure multiple accelerometers at the same time, if the accelerometer is not tested after it is powered on, the output end of the untested accelerometer will be suspended, which will cause damage to the accelerometer body; or the accelerometer being tested adopts a scheme of powering on one by one, which will increase the total test time and cannot effectively improve the test efficiency. In addition, the accelerometer test device can only perform repetitive tests under simple working conditions, which is not suitable for working conditions of multiple working conditions and long-term power-on tests. Summary of the invention

[0004] The present invention provides an accelerometer test circuit system, which tests multiple accelerometers simultaneously by measuring a conversion circuit through a logic switch or consuming a power resistor. When the conversion circuit is enabled, current flows into the conversion circuit for testing, and the test result has high reliability. When the conversion circuit is not enabled, the accelerometer current flows into the power consumption resistor, thereby preventing the output end of the untested accelerometer from being unloaded and causing damage to the accelerometer. The test circuit system is small in size and light in weight, and is convenient for turnover and movement.

[0005] The technical solution adopted by the present invention to solve the technical problem is: An accelerometer test circuit system is used to test multiple accelerometers at the same time. The accelerometer test circuit system includes a logic switch, an MCU processor, a conversion circuit and a power consumption resistor. Each accelerometer is connected to the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch. The logic switches are connected to the MCU processor. The MCU processor controls the logic switch to select the accelerometer and the conversion circuit or the accelerometer and the power consumption resistor. The conversion circuit is connected to the MCU processor. When the accelerometer is connected to the conversion circuit, the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal. The conversion circuit sends the frequency signal to the MCU processor.

[0006] The MCU processor is connected to a host computer, and the host computer sends a control instruction to the MCU processor and receives a frequency signal from the accelerometer.

[0007] The accelerometer test circuit system also includes a power supply module, which provides working power to the accelerometer and various components in the accelerometer test circuit system.

[0008] The power supply module includes a 220V alternating current, an AC / DC power supply module and a DC / DC power supply module connected in series.

[0009] The accelerometer test circuit system is packaged into a test device, a plurality of accelerometers are assembled on a test fixture, and the test device is connected to the test fixture via a test cable.

[0010] The MCU processor is provided with 16 control channels, and each control channel is connected to 3 logic switches.

[0011] The logic switch is an analog logic switch.

[0012] The conversion circuit includes an integration circuit, a threshold circuit, a control circuit, a bridge switch circuit, a constant current source circuit, a constant current source temperature compensation circuit, a clock circuit and an output drive circuit. The input end of the integration circuit is connected to the accelerometer through a logic switch. When the logic switch selects the accelerometer and the conversion circuit, the integration circuit integrates the input current of the accelerometer. The threshold circuit is connected to the output end of the integration circuit, the control circuit is connected to the output end of the threshold circuit and is simultaneously connected to the output drive circuit and the clock circuit. The bridge switch circuit is simultaneously connected to the output end of the control circuit, the output end of the constant current source circuit and the input end of the integration circuit, and the constant current source temperature compensation circuit is connected to the constant current source circuit.

[0013] The resistance of the power consumption resistor is 500Ω~3.5KΩ.

[0014] Compared with the prior art, the accelerometer test circuit system provided by the present invention has the following advantages: (1) The accelerometer test circuit system provided by the present invention tests multiple accelerometers simultaneously by measuring the conversion circuit through a logic switch or consuming a power resistor, and the test result is not affected by the failure of the sampling resistor, and the reliability is high; when the conversion circuit is selected, the current flows into the conversion circuit for testing, and when the accelerometer is not selected, the accelerometer current flows into the power consumption resistor, ensuring that the accelerometer can be powered on for a long time, avoiding the output end of the untested accelerometer from being unloaded, thereby damaging the accelerometer.

[0015] (2) The accelerometer test circuit system provided by the present invention measures the output current of the accelerometer through a conversion circuit to achieve the test of the accelerometer; when used for a long time, the scale factor (K1) and zero offset (K0) of the accelerometer can be tested and calibrated by a simple method, and the accuracy of the accelerometer can be calibrated at any time to avoid invalid tests.

[0016] (3) The accelerometer test circuit system provided by the present invention has a high degree of automation and integration, is easy to operate, and can reduce potential hazards introduced to the accelerometer of the upper product due to improper operation. In addition, the packaged test equipment is small in size and light in weight, which is convenient for turnover and transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A principle block diagram of the accelerometer test circuit system provided by the present invention; Figure 2 is a gating control circuit diagram of a logic switch in the present invention; Figure 3 It is a principle block diagram of the conversion circuit in the present invention. DETAILED DESCRIPTION

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] The accelerometer test circuit system provided in this embodiment includes a logic switch, an MCU processor, a conversion circuit, a power consumption resistor and a power supply module. The principle block diagram is as follows: Figure 1 The power supply module provides working power for the accelerometer and various components in the accelerometer test circuit system. Specifically, the power supply module includes 220V AC, AC / DC power supply module and DC / DC power supply module connected in series, that is, the external power supply adopts 220V AC, and the internal power supply is powered by an AC / DC power supply module and two DC / DC power supply modules connected in series to power various components (including the accelerometer).

[0020] In this embodiment, the logic switch, MCU processor, conversion circuit, power consumption resistor of the accelerometer test circuit system, and the AC / DC power module and DC / DC power module in the power module are packaged together into a test device. Multiple accelerometers are assembled on the test fixture, and the test device is connected to the 220V AC power of the power module and the test fixture through the test cable. The test device and the test fixture are both independent components, and the test device is powered by an external 220V AC power, which can ensure that the accelerometer can be tested under various working conditions and avoid damage to the accelerometer due to improper operation of personnel. In addition, the overall structure of the package is small in size and light in weight, which is convenient for handling and turnover, and is suitable for testing under multiple working conditions.

[0021] Each accelerometer is connected to the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch. The logic switches are all connected to the MCU processor, and the MCU processor controls the logic switch to select the accelerometer and the conversion circuit or the accelerometer and the power consumption resistor; the conversion circuit is connected to the MCU processor, and when the accelerometer is connected to the conversion circuit (that is, the accelerometer is in the test state), the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal, and the conversion circuit sends the frequency signal to the MCU processor, and the MCU processor uses FPGA technology to solve and process the frequency signal, and outputs the test result data in real time. When the accelerometer is connected to the power consumption resistor (that is, the accelerometer is not tested), the untested accelerometer consumes power to avoid the accelerometer output terminal being suspended and causing damage to the accelerometer. Specifically, the model of the MCU processor is GD32H7×. In this embodiment, the MCU processor is connected to the host computer (such as an industrial computer, a computer), and interacts in a response manner. The host computer sends a control instruction (sends an instruction) to the MCU processor and receives the frequency signal of the accelerometer (receives data).

[0022] The workflow of the accelerometer test circuit system provided in this embodiment is as follows: after the test circuit system is powered on, the logic switch defaults to a high level, and at this time, the outputs of all accelerometers flow into the power consumption resistor to consume power. This measure can ensure that the test system can handle the standby state for a long time. When the host computer sends a start test instruction, the MCU processor controls to open the logic switch of the corresponding channel, connects the accelerometer of the channel with the conversion circuit, and makes the current of the accelerometer of the channel flow into the conversion circuit for sampling and processing, thereby realizing accurate measurement of the accelerometer current.

[0023] In this embodiment, the MCU processor is provided with 16 control channels, namely, channel 1 to channel 16, and each control channel is connected to 3 logic switches, namely, the MCU processor in this embodiment can control 48 logic switches, and correspondingly, a maximum of 48 accelerometers can be installed on the test fixture, and 48 accelerometers can be tested at one time. The MCU processor controls one channel at a time, namely, controls 3 logic switches to select the conversion circuit and 3 accelerometers at a time, and the conversion circuit tests 3 accelerometers at the same time. The MCU processor receives the instructions of the host computer, controls the FPGA intelligent switching channel according to the predetermined process, automatically collects multi-channel accelerometer signals, and sends the test results to the host computer in real time, which can realize multi-channel fully automatic testing without manual operation. The intelligent test of the predetermined process can be completed through the instructions of a host computer, effectively improving the test efficiency and safety of the accelerometer.

[0024] Figure 2 This is the gating control circuit diagram of the three logic switches (U11, U12, U13) on channel 1 (KIO-1). The IN end of each logic switch is connected to channel 1 (KIO-1) of the MCU processor, the VDD end of each logic switch is connected to the power module for power, the D end (pin 5) of each logic switch is connected to the accelerometer (JDX-1, JDY-1, JDZ-1), the S1 end (pin 4) of each logic switch is connected to the power consumption resistor (R31, R35, R39), and the S2 end (pin 6) of each logic switch is connected to the conversion circuit. When the test system is powered on or does not receive the test command, the accelerometer output current flows from pin 5 to pin 4 and then flows out, thereby preventing the accelerometer output terminal from being suspended. After receiving the test command, the accelerometer output current flows from pin 5 to pin 6 and then flows into the conversion circuit, thereby performing simultaneous testing of the accelerometers (JDX-1, JDY-1, JDZ-1). Specifically, the logic switch is an analog logic switch, which has the advantages of low insertion loss, high isolation, fast switching speed, good temperature stability, etc., and has an ESD protection circuit, and is reliable to use. The resistance value of the power consumption resistor in this embodiment is 1KΩ.

[0025] The conversion circuit in this embodiment includes an integration circuit, a threshold circuit, a control circuit, a bridge switch circuit, a constant current source circuit, a constant current source temperature compensation circuit, a clock circuit and an output drive circuit. The principle block diagram is shown in FIG. Figure 3 The input end of the integration circuit is connected to the accelerometer through a logic switch. When the logic switch selects the accelerometer and the conversion circuit, the integration circuit is sensitive to the input current (I 入) for integration, the threshold circuit is connected to the output end of the integration circuit, the integration signal is push-pull output to the threshold circuit, the control circuit is connected to the output end of the threshold circuit and is also connected to the output drive circuit and the clock circuit, the bridge switch circuit is simultaneously connected to the output end of the control circuit, the output end of the constant current source circuit and the input end of the integration circuit, and the constant current source temperature compensation circuit is connected to the constant current source circuit. The main function of the threshold circuit and the control circuit is to determine the size and polarity of the input current according to the size of the output voltage of the integration circuit in each clock cycle under the action of the reference 512kHz square wave clock signal, so as to control the on and off (selection control) of the bridge switch circuit, that is, the control circuit controls the feedback of different constant current sources by detecting the change of the threshold voltage, thereby realizing the control of the circuit; the constant current source circuit includes positive and negative constant current sources (I 恒 ), which is the electronic weight for current / frequency conversion and is the key component to ensure conversion accuracy. The main function of the clock circuit is to provide a high-precision clock reference for the conversion circuit, which is the basis for the conversion circuit to improve linearity by using equal-width control; the main function of the output drive circuit is to provide sufficient current driving capability for the output pulse signal (TTL pulse). The conversion circuit has the characteristics of high reliability and high conversion accuracy.

[0026] The accelerometer output current is measured through the conversion circuit to achieve the test of the accelerometer; when used for a long time, the scale factor (K1) and zero offset (K0) of the accelerometer can be tested and calibrated by a simple method, which can be used for long-term monitoring of the two indicators of the accelerometer scale factor (K1) and zero offset (K0). Specifically, the constant current source temperature compensation circuit includes a temperature compensated crystal oscillator, which uses a temperature compensated high-precision crystal oscillator, and its frequency stability index is better than 2ppm within the temperature range of -55℃ to +85℃. The scale factor (K1) nonlinear correction technology and the temperature compensation method of the current / frequency conversion circuit reference constant current source are used to reduce the change of the scale factor within the working range.

Claims

1. An accelerometer test circuit system for testing multiple accelerometers simultaneously, characterized in that: The accelerometer test circuit system includes a logic switch, an MCU processor, a conversion circuit and a power consumption resistor. Each accelerometer is connected to the conversion circuit and the power consumption resistor through a single-pole double-throw logic switch. The logic switches are connected to the MCU processor. The MCU processor controls the logic switch to select the accelerometer and the conversion circuit or the accelerometer and the power consumption resistor; the conversion circuit is connected to the MCU processor. When the accelerometer is connected to the conversion circuit, the conversion circuit performs analog-to-digital conversion on the output current of the accelerometer and outputs a frequency signal. The conversion circuit sends the frequency signal to the MCU processor.

2. The accelerometer test circuit system according to claim 1, characterized in that: The MCU processor is connected to a host computer, and the host computer sends a control instruction to the MCU processor and receives a frequency signal from the accelerometer.

3. The accelerometer test circuit system according to claim 1, characterized in that: The accelerometer test circuit system also includes a power supply module, which provides working power to the accelerometer and various components in the accelerometer test circuit system.

4. The accelerometer test circuit system according to claim 3, characterized in that: The power supply module includes a 220V alternating current, an AC / DC power supply module and a DC / DC power supply module connected in series.

5. The accelerometer test circuit system according to claim 1, characterized in that: The accelerometer test circuit system is packaged into a test device, a plurality of accelerometers are assembled on a test fixture, and the test device is connected to the test fixture via a test cable.

6. The accelerometer test circuit system according to claim 1, characterized in that: The MCU processor is provided with 16 control channels, and each control channel is connected to 3 logic switches.

7. The accelerometer test circuit system according to claim 1, characterized in that: The logic switch is an analog logic switch.

8. The accelerometer test circuit system according to claim 1, characterized in that: The conversion circuit includes an integration circuit, a threshold circuit, a control circuit, a bridge switch circuit, a constant current source circuit, a constant current source temperature compensation circuit, a clock circuit and an output drive circuit. The input end of the integration circuit is connected to the accelerometer through a logic switch. When the logic switch selects the accelerometer and the conversion circuit, the integration circuit integrates the input current of the accelerometer. The threshold circuit is connected to the output end of the integration circuit, the control circuit is connected to the output end of the threshold circuit and is simultaneously connected to the output drive circuit and the clock circuit. The bridge switch circuit is simultaneously connected to the output end of the control circuit, the output end of the constant current source circuit and the input end of the integration circuit, and the constant current source temperature compensation circuit is connected to the constant current source circuit.

9. The accelerometer test circuit system according to claim 1, characterized in that: The resistance of the power consumption resistor is 500Ω~3.5KΩ.

Images