Constant magnetic field control system and method of magnetic finder for robot

Abstract

The invention relates to the technical field of defect detection, in particular to a robot magnetic detector constant magnetic field control system and method, and the system comprises a control circuit, a power supply circuit, a magnet yoke winding drive circuit, a magnet yoke winding current detection circuit, a magnet yoke winding temperature detection circuit, a magnetic field detection circuit and a switching signal input and output circuit. The robot magnetic detector constant magnetic field control system and method have the advantages that high-precision constant magnetic control is achieved, detection quality can be guaranteed, intelligent temperature protection can be achieved, equipment damage is prevented, anti-interference design is carried out, signal acquisition reliability can be improved, multi-state indication and remote control are achieved, operation efficiency can be improved, and the robot magnetic detector constant magnetic field control system and method are suitable for popularization and application. The whole system is compact in structure and reasonable in circuit layout, adapts to robot integration, and meets automatic detection requirements of special equipment in complex environments such as high altitude and closed environments.

Description

Technical Field

[0001] This invention relates to the field of defect detection technology, and in particular to a constant magnetic field control system and method for a magnetic detector for robots. Background Technology

[0002] In the inspection of weld defects in large pressure equipment (such as spherical tanks and pressure vessels), traditional manual inspection methods present significant technical bottlenecks and safety hazards. Before inspection, workers must perform a series of tedious and time-consuming preparatory tasks, including purging toxic gases, erecting scaffolding, and manually cleaning and grinding the weld area. During inspection, personnel must carry non-destructive testing equipment to work at heights, which is not only physically demanding but also carries risks of falls and poisoning / asphyxiation. This manual inspection model not only leads to prolonged production interruptions but also severely restricts capacity expansion.

[0003] To address the aforementioned issues, magnetic particle inspection robots have been introduced into weld flaw detection operations. These robots can avoid the need for scaffolding construction, improve the working environment, and increase inspection efficiency. The magnetic detector, as the core magnetization unit of this type of robot, is typically used to generate a rotating magnetic field to achieve multi-directional magnetization. However, during actual operation, the continuous consumption of the robot's battery power causes a drop in the magnetic detector's power supply voltage, and changes in ambient temperature also lead to alterations in the impedance of the yoke winding. Both of these factors directly affect the stability of the output magnetic field.

[0004] Furthermore, in the top and middle areas of large equipment such as spherical tanks, the high position makes it difficult to attach sensitivity test pieces to verify the working status of the magnetic detector. The robot must be moved back to the bottom to complete the functional verification, which interrupts the testing process and severely impacts efficiency. Therefore, existing technologies lack a magnetic detector control system capable of continuously outputting a constant magnetic field under voltage fluctuations and temperature changes, and possessing real-time status monitoring and remote control functions. This makes it difficult to meet the accuracy and reliability requirements of automated robotic testing. Summary of the Invention

[0005] The main objective of this invention is to overcome the shortcomings of the prior art and provide a constant magnetic field control system and method for a magnetic detector for robots.

[0006] The technical solution adopted by the present invention to achieve its technical objective is: a constant magnetic field control system for a robot magnetic detector, including a control circuit, a power supply circuit, a magnetic yoke winding drive circuit, a magnetic yoke winding current detection circuit, a magnetic yoke winding temperature detection circuit, a magnetic field detection circuit, and a switch signal input / output circuit.

[0007] Preferably, the control circuit includes a microcontroller U2 and an H-bridge driver chip U3, wherein the microcontroller U2 includes a central processing unit, an SPWM module, an ADC module, and an I / O module;

[0008] The SPWM module is connected to the yoke winding drive circuit through the H-bridge driver chip U3. The ADC module is connected to the battery power detection unit, yoke winding current detection circuit, yoke winding temperature detection circuit and magnetic field detection circuit in the power supply circuit. The IO module is connected to the switch signal input and output circuit.

[0009] Preferably, the power supply circuit includes a battery, a π-type filter unit consisting of an inductor L5 and capacitors C9 and C10, a step-down chip U1, a battery power detection unit, and isolation devices for the high-voltage side and the low-voltage side ground lines;

[0010] The battery is filtered by a π-type filter unit and then supplies power to the high-voltage side on one side, and to the low-voltage side after being stepped down by a step-down chip U1 on the other side.

[0011] The power supply circuit has four external ports, namely Vbat, VCC, PGND and GND. Vbat is the positive terminal of the high voltage side, PGND is the ground of the high voltage side, VCC is the positive terminal of the low voltage side, and PGND is the ground of the low voltage side.

[0012] The PGND and GND terminals are connected by an isolation device to reduce mutual interference between the high-voltage side and the low-voltage side. The isolation device is a 0Ω resistor R9, an inductor, a ferrite bead, a section of wire or trace.

[0013] Preferably, it also includes a cross yoke, which includes a first yoke, a second yoke, winding AB, winding CD, thermistor RT1, thermistor RT2, linear Hall sensor U8, and linear Hall sensor U10.

[0014] The first and second magnetic yokes are arranged independently and crosswise. The winding AB is wound on the first magnetic yoke, and the winding CD is wound on the second magnetic yoke. The two windings are powered independently and the current magnitude and phase of each winding are controlled independently.

[0015] Thermistors RT1 and RT2 are respectively installed at the bottom of the windings of the two magnetic yokes, and the linear Hall sensors U8 and U10 are respectively installed on the sides of the two magnetic yokes near the bottom.

[0016] Preferably, the two windings are composed of and driven by two independent magnetic yoke winding drive circuits. The two magnetic yoke winding drive circuits have the same structure and parameters, and are composed of MOSFETs Q1, Q2, Q3, Q4, sampling resistors RS1 and RS2, resistors R1, R2, R3, and R4, and capacitors C1, C2, C3, and C4.

[0017] In the magnetic yoke winding drive circuit, each drive circuit has four groups of MOS transistors, which form an H-bridge circuit to supply power to the magnetic yoke winding; the sampling resistor is located in the lower arm of the H-bridge and is used to detect the current flowing through the magnetic yoke winding; the resistor and capacitor form a first-order RC filter circuit, which is connected between the output terminal of the H-bridge drive chip U3 and the gate of the MOS transistor to enhance the anti-interference capability of the MOS transistor when it is working.

[0018] Preferably, the two windings are detected by two independent yoke winding current detection circuits, and the current flowing through the two windings is measured independently. The two yoke winding current detection circuits have the same structure and parameters, and are composed of operational amplifier U4, operational amplifier U5, resistors R12, R13, R14, R15, R16, R17, R18, capacitors C14, C15, C16 and C17.

[0019] In the yoke winding current detection circuit, the operational amplifier and resistors form a forward amplifier circuit to amplify the signals collected by sampling resistors RS1 and RS2; the resistors and capacitors form a first-order RC filter circuit, which is connected to the non-inverting input and inverting input of the operational amplifier, respectively, to filter out interference signals coupled in by the current sampling resistors and signal traces.

[0020] Preferably, the two windings are detected by two independent magnetic yoke winding temperature detection circuits, and the temperature of the magnetic yoke windings is determined by detecting the resistance values ​​of thermistors RT1 and RT2, respectively. The two magnetic yoke winding temperature detection circuits have the same structure and parameters, and are composed of operational amplifier U6, operational amplifier U7, thermistors RT1 and RT2, resistors R18, R19, R20, R21, R22, R23, capacitors C18 and C19.

[0021] In the magnetic yoke winding temperature detection circuit, the operational amplifier and the resistor form a voltage follower, which plays the role of impedance transformation. Resistors R19 and R22 are also provided between the thermistor and the low-voltage side ground line to block the coupling interference from the thermistor and its signal trace, so as to avoid it from affecting the low-voltage side ground line.

[0022] Preferably, the magnetic field generated by the two magnetic yokes is detected by two independent magnetic field detection circuits. The magnetic field generated by the cross magnetic yokes is detected by linear Hall sensor U8 and linear Hall sensor U10. The two magnetic field detection circuits have the same structure and parameters, and are composed of operational amplifier U9, operational amplifier U11, resistor R26, resistor R27, resistor R28, resistor R29, resistor R30, resistor R31, capacitor C21 and capacitor C22.

[0023] In the magnetic field detection circuit, the operational amplifier and the resistor form a positive amplification circuit, and the resistor and capacitor form a first-order RC filter circuit connected to the positive input terminal of the operational amplifier.

[0024] Preferably, the switch signal input / output circuit includes LED D1, LED D2, LED D3, switch diode D4, resistor R32, resistor R33, resistor R34, resistor R35, and resistor R36.

[0025] In the switch signal input / output circuit, the three light-emitting diodes are used to display the working status, fault status, and battery power status of the magnetic detector, respectively. The negative terminal of the switch diode D4 is connected to the robot controller. When the robot controller outputs a high level, the switch diode D4 is cut off; when the robot controller outputs a low level, the switch diode D4 is turned on, transmitting the control signal of the robot controller to the control circuit to control the start and stop of the magnetic detector.

[0026] The present invention also provides a method for controlling a constant magnetic field in a magnetic detector for robots, comprising the following steps:

[0027] S1. The control circuit detects the start signal at the Ki1 terminal of the switching diode D4, and the magnetic detector starts working and lights up the light-emitting diode D1.

[0028] S2. After startup, the controller synchronously monitors multiple operating parameters of the magnetic detector in real time and controls the magnetic field generated by the magnetic detector:

[0029] S3. The temperature of the magnetic yoke winding is collected by thermistors RT1 and RT2. If the temperature is abnormal, the light-emitting diode D2 is lit.

[0030] S4. Determine the battery power level through the battery power detection unit. If the power level is sufficient, light up LED D3.

[0031] S5. The magnetic field generated by the cross yoke is detected by linear Hall sensor U8 and linear Hall sensor U10. The magnetic field strength is kept constant by controlling the magnitude of the current flowing through winding AB and winding CD.

[0032] S6. When the control circuit detects the stop signal at the Ki1 terminal, the magnetic detector stops working and turns off LEDs D1, D2, and D3.

[0033] The working principle and specific usage procedure of the constant magnetic field control system and method for the robot using a magnetic detector are as follows:

[0034] Working Principle: Through real-time monitoring and closed-loop feedback control, the magnetic field detector ensures a constant magnetic field output during robot inspection. The system's core is a control circuit (microcontroller U2 and H-bridge driver chip U3), receiving multiple feedback signals from the magnetic field detection circuit (linear Hall sensors U8 and U10), the yoke winding current detection circuit (sampling resistors RS1 and RS2 and operational amplifiers U4 and U5), and the yoke winding temperature detection circuit (thermistors RT1 and RT2 and operational amplifiers U6 and U7). When battery voltage fluctuations or ambient temperature changes cause changes in winding impedance, the magnetic field strength shifts. The control circuit adjusts the output of the H-bridge driver chip via the SPWM module, independently controlling the current magnitude and phase of the two crossed yoke windings (AB and CD), thereby restoring the magnetic field to the set value and achieving constant magnetic field control.

[0035] Specific operating procedure: After the system is powered on, the robot controller sends a start signal (Ki1 terminal low level) to the control circuit through the switching diode D4 in the switch signal input / output circuit. The magnetic detector starts and illuminates the working status indicator D1. Subsequently, the system enters a real-time monitoring and control cycle: the temperature detection circuit continuously monitors the winding temperature; if abnormal, the fault indicator D2 is illuminated; the battery power detection unit judges the battery status; if sufficient, the power indicator D3 is illuminated; simultaneously, the linear Hall sensor collects the magnetic field strength in real time, and the control circuit dynamically adjusts the winding current based on the feedback to ensure a constant magnetic field. When a stop signal (Ki1 terminal high level) is detected, the system shuts down all outputs and turns off the indicator lights, completing the detection process.

[0036] Compared with the prior art, the beneficial effects of the present invention are:

[0037] The robot uses a constant magnetic field control system and method for magnetic particle detectors, which has high-precision constant magnetic field control to ensure detection quality: by using linear Hall sensors to monitor the magnetic field generated by the two crossed magnetic yokes in real time, combined with a closed-loop feedback control algorithm, the current magnitude and phase of each winding are independently adjusted. Even when the battery voltage drops or the winding impedance drifts due to temperature changes, the magnetic field strength can be kept constant, thereby avoiding missed detections or misjudgments and improving the accuracy of magnetic particle detection.

[0038] This robot utilizes a constant magnetic field control system and method based on a magnetic detector to achieve intelligent temperature protection and prevent equipment damage. Thermistors are installed near the two yoke windings to collect winding temperatures in real time. When the temperature exceeds a safe threshold, the system can promptly issue a fault alarm (illuminating fault indicator D2) or take protective measures, effectively preventing the yoke windings from burning out due to overheating. This solves the problem of easy damage caused by the inability of personnel to directly sense the temperature when the magnetic detector is integrated into the robot.

[0039] The robot uses a constant magnetic field control system and method for a magnetic detector, and incorporates anti-interference design to improve the reliability of signal acquisition: In the temperature detection circuit, the thermistor is connected to the low-voltage side ground wire through a dedicated resistor. Combined with a voltage follower and filter circuit, it effectively blocks coupling interference from long-line transmission, avoids contamination of the low-voltage side ground wire, and ensures the accuracy of temperature sampling and the stable operation of the system.

[0040] This robot utilizes a constant magnetic field control system and method for a magnetic detector, featuring multi-state indication and remote control to improve operational efficiency. Three LEDs indicate the operating status, fault status, and battery level, allowing operators to quickly grasp the equipment's operational status. The input / output circuit, composed of switching diodes, seamlessly interfaces with the robot controller, enabling remote start and stop of the magnetic detector. This avoids interruptions to the detection process due to functional verification, significantly improving the continuity and efficiency of automated detection.

[0041] The robot uses a constant magnetic field control system and method for magnetic particle inspection. The system has a compact structure and is suitable for robot integration: the system integrates power management, drive control, signal acquisition and communication interface into one unit. The circuit layout is reasonable and can be easily integrated into magnetic particle inspection robots to meet the automated inspection needs of special equipment in complex environments such as high altitude and enclosed spaces. Attached Figure Description

[0042] Figure 1 This is the control circuit diagram of the present invention.

[0043] Figure 2 This is the overall circuit control diagram of the present invention.

[0044] Figure 3 This is the power supply circuit diagram for the present invention.

[0045] Figure 4 This is a schematic diagram of the sensor arrangement in the cross yoke of the present invention.

[0046] Figure 5 This is a circuit diagram of the magnetic yoke winding drive of the present invention.

[0047] Figure 6 This is a circuit diagram of the magnetic yoke winding current detection circuit of the present invention.

[0048] Figure 7 This is a circuit diagram of the magnetic yoke winding temperature detection circuit of the present invention.

[0049] Figure 8 This is a circuit diagram of the magnetic field detection circuit of the present invention.

[0050] Figure 9 This is a circuit diagram of the switch signal input and output of the present invention.

[0051] Figure 10This is a schematic diagram of the magnetic field control principle of the magnetic detector of the present invention.

[0052] Figure 11 This is a system workflow diagram of the present invention.

[0053] Wherein: 1. First magnetic yoke; 2. Second magnetic yoke. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0055] In the description of this invention, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to or indirectly connected to the other element.

[0056] In the description of this invention, it should be noted that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0057] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0058] Example 1:

[0059] Please see Figures 1-10 A constant magnetic field control system for a robot magnetic detector includes a control circuit, a power supply circuit, a yoke winding drive circuit, a yoke winding current detection circuit, a yoke winding temperature detection circuit, a magnetic field detection circuit, and a switch signal input / output circuit.

[0060] In this embodiment, Figure 2 The overall circuit control diagram shows that the power supply circuit provides the necessary operating power to the control circuit, the yoke winding drive circuit, the switch signal input / output circuit, and various detection circuits. The control circuit detects the magnetic field generated by the yoke winding through the magnetic field detection circuit, and simultaneously outputs an SPWM signal to the yoke winding drive circuit to control the magnetic field generated by the yoke winding, thereby achieving closed-loop control of the magnetic field. The yoke winding current detection circuit and the yoke winding temperature detection circuit detect the current flowing through the yoke winding and the temperature of the yoke winding, respectively, and transmit the collected signals to the control circuit for protection judgment, realizing overcurrent and overtemperature protection. The switch signal input / output circuit is connected to the control circuit and is used to receive external commands and output the status of the magnetic detector.

[0061] In this implementation, Figure 1 The control circuit diagram includes a microcontroller U2 and an H-bridge driver chip U3, wherein the microcontroller U2 includes a central processing unit, an SPWM module, an ADC module, and an I / O module;

[0062] The SPWM module is connected to the yoke winding drive circuit through the H-bridge driver chip U3. The ADC module is connected to the battery power detection unit, yoke winding current detection circuit, yoke winding temperature detection circuit and magnetic field detection circuit in the power supply circuit. The IO module is connected to the switch signal input and output circuit.

[0063] In this implementation, Figure 3 The power supply circuit diagram includes a battery, a π-type filter unit consisting of an inductor L5 and capacitors C9 and C10, a step-down chip U1, a battery power detection unit, and isolation devices for the high-voltage side and low-voltage side ground lines.

[0064] The battery is filtered by a π-type filter unit and then supplies power to the high-voltage side on one side, and to the low-voltage side after being stepped down by a step-down chip U1 on the other side.

[0065] The power supply circuit has four external ports, namely Vbat, VCC, PGND and GND. Vbat is the positive terminal of the high voltage side, PGND is the ground of the high voltage side, VCC is the positive terminal of the low voltage side, and PGND is the ground of the low voltage side.

[0066] The PGND and GND terminals are connected by an isolation device to reduce mutual interference between the high-voltage side and the low-voltage side. The isolation device is a 0Ω resistor R9, an inductor, a ferrite bead, a section of wire or trace.

[0067] Specifically, Vbat of the power supply circuit is connected to the positive terminal of the battery, and PGND is connected to the negative terminal of the battery. Electrical energy passes through a π-type filter composed of capacitor C9, inductor L5, and capacitor C10 to the POWER terminal, and then is stepped down by the voltage-dropping chip U1 before reaching the VCC terminal. The POWER terminal supplies power to the high-voltage side of the device, and the VCC terminal supplies power to the low-voltage side. R9 is a 0Ω resistor, connecting the PGND and GND terminals to reduce mutual interference between the high-voltage and low-voltage sides. Resistors R10 and R11, along with capacitor C11, form the battery power detection unit.

[0068] In this implementation, Figure 4 The diagram shows the arrangement of sensors in the cross magnetic yoke, which also includes the cross magnetic yoke. The cross magnetic yoke includes a first magnetic yoke 1, a second magnetic yoke 2, windings AB and CD, thermistors RT1 and RT2, a linear Hall sensor U8, and a linear Hall sensor U10.

[0069] The first yoke 1 and the second yoke 2 are arranged independently and crosswise. The winding AB is wound on the first yoke 1 and the winding CD is wound on the second yoke 2. The two windings are powered independently and the current magnitude and phase of each winding are controlled independently. The winding AB is wound on the first yoke 1 to form the winding inductance L1 and the wire inductance L2. The winding CD is wound on the second yoke 2 to form the wire inductance L3 and the wire inductance L4.

[0070] Thermistors RT1 and RT2 are respectively installed at the bottom of the windings of the two magnetic yokes, and the linear Hall sensors U8 and U10 are respectively installed on the sides of the two magnetic yokes near the bottom.

[0071] In this implementation, Figure 5The diagram shows the magnetic yoke winding drive circuit. The two windings are composed of and driven by two independent magnetic yoke winding drive circuits. The two magnetic yoke winding drive circuits have the same structure and parameters, and are composed of MOSFETs Q1, Q2, Q3, Q4, sampling resistors RS1 and RS2, resistors R1, R2, R3, and R4, and capacitors C1, C2, C3, and C4.

[0072] In the magnetic yoke winding drive circuit, each drive circuit has four groups of MOS transistors, which form an H-bridge circuit to supply power to the magnetic yoke winding; the sampling resistor is located in the lower arm of the H-bridge and is used to detect the current flowing through the magnetic yoke winding; the resistor and capacitor form a first-order RC filter circuit, which is connected between the output terminal of the H-bridge drive chip U3 and the gate of the MOS transistor to enhance the anti-interference capability of the MOS transistor when it is working.

[0073] Specifically, the sampling resistor RS1 is used to detect the current flowing through winding AB. Resistors R1, R2, R3, and R4 are respectively connected to the H-bridge driver chip U3. Resistors R1 and C1, R2 and C2, R3 and C3, and R4 and C4 respectively constitute a first-order RC filter circuit.

[0074] In this implementation, Figure 6 The diagram shows the current detection circuit for the yoke winding. The two windings are detected by two independent yoke winding current detection circuits, which independently measure the current flowing through the two windings. The two yoke winding current detection circuits have the same structure and parameters, and are composed of operational amplifier U4, operational amplifier U5, resistors R12, R13, R14, R15, R16, R17, R18, and capacitors C14, C15, C16, and C17.

[0075] In the yoke winding current detection circuit, the operational amplifier and resistors form a forward amplifier circuit to amplify the signals collected by sampling resistors RS1 and RS2; the resistors and capacitors form a first-order RC filter circuit, which is connected to the non-inverting input and inverting input of the operational amplifier, respectively, to filter out interference signals coupled in by the current sampling resistors and signal traces.

[0076] Specifically, two independent magnetic yoke winding detection circuits detect the voltage across sampling resistors RS1 and RS2, respectively. According to Ohm's law, the ratio of voltage to resistance is the current, from which the current flowing through windings AB and CD can be calculated. The circuit for detecting the current flowing through winding AB includes operational amplifier U4, sampling resistor RS1, resistors R12, R13, and R14, and capacitors C14 and C15. Operational amplifier U4, resistors R12 and R13 form a forward amplifier circuit, amplifying the voltage signal across resistor RS1. Resistor R14 and capacitor C15 form a first-order RC filter circuit to filter out interference signals on resistor RS1. Capacitor C14 is used to filter out ground interference on the high-voltage side.

[0077] In this implementation, Figure 7 This is a circuit diagram for detecting the temperature of the yoke windings. The two windings are detected by two independent yoke winding temperature detection circuits. The temperature of the yoke windings is determined by detecting the resistance values ​​of thermistors RT1 and RT2, respectively. The two yoke winding temperature detection circuits have the same structure and parameters, and are composed of operational amplifier U6, operational amplifier U7, thermistors RT1 and RT2, resistors R18, R19, R20, R21, R22, R23, capacitors C18 and C19.

[0078] In the magnetic yoke winding temperature detection circuit, the operational amplifier and the resistor form a voltage follower, which plays the role of impedance transformation. Resistors R19 and R22 are also provided between the thermistor and the low-voltage side ground line to block the coupling interference from the thermistor and its signal trace, so as to avoid it from affecting the low-voltage side ground line.

[0079] Specifically, two independent yoke winding detection circuits are used to detect the resistance values ​​of thermistors RT1 and RT2 to determine the temperature of the yoke windings. The circuit for detecting the resistance value of thermistor RT1 includes operational amplifier U6, resistors R18, R19, R20, R21, and capacitor C18. The operational amplifier U6 and resistor R21 form a voltage follower, which acts as an impedance transformer. Resistor R19 is connected in series between the thermistor and the low-voltage side ground line. This design can effectively block coupling interference from thermistor RT1 and its signal traces, preventing it from affecting the low-voltage side ground line. The thermistor RT1, resistors R18, R19, R20, and capacitor C18 constitute the thermistor RT1 resistance measurement unit.

[0080] In this implementation, Figure 8The diagram shows a magnetic field detection circuit. The magnetic field generated by the two magnetic yokes is detected by two independent magnetic field detection circuits. The magnetic field generated by the crossed magnetic yokes is detected by linear Hall sensors U8 and U10. The two magnetic field detection circuits have the same structure and parameters, and are composed of operational amplifiers U9 and U11, resistors R26, R27, R28, R29, R30, R31, capacitors C21 and C22.

[0081] In the magnetic field detection circuit, the operational amplifier and the resistor form a positive amplification circuit, and the resistor and capacitor form a first-order RC filter circuit connected to the positive input terminal of the operational amplifier.

[0082] Specifically, two independent yoke winding detection circuits detect the magnetic field generated by the crossed yokes using linear Hall sensors U8 and U10. Linear Hall sensor U8 detects the magnetic field generated by the first yoke 1, and linear Hall sensor U10 detects the magnetic field generated by the second yoke 2. The yoke winding detection circuit includes an operational amplifier U9, resistors R26, R27, and R28, and a capacitor C21. The operational amplifier U9, along with resistors R26 and R27, forms a forward amplification circuit. Resistor R28 and capacitor C21 form a first-order RC filter circuit. This structure amplifies the magnetic field signal acquired by the linear Hall sensor U8 and filters out high-frequency interference.

[0083] In this implementation, Figure 9 This is a circuit diagram for a switch signal input / output circuit. The switch signal input / output circuit includes LED D1, LED D2, LED D3, switch diode D4, resistor R32, resistor R33, resistor R34, resistor R35, and resistor R36.

[0084] In the switch signal input / output circuit, the three light-emitting diodes are used to display the working status, fault status, and battery power status of the magnetic detector, respectively. The negative terminal of the switch diode D4 is connected to the robot controller. When the robot controller outputs a high level, the switch diode D4 is cut off; when the robot controller outputs a low level, the switch diode D4 is turned on, transmitting the control signal of the robot controller to the control circuit to control the start and stop of the magnetic detector.

[0085] Specifically, LEDs D1, D2, and D3 are used to indicate the working status of the magnetic detector. When LED D1 is lit, it indicates that the magnetic detector is working; when LED D2 is lit, it indicates that the magnetic detector has malfunctioned; and when LED D3 is lit, it indicates that the battery is fully charged.

[0086] The Ki1 terminal of the switching diode D4 is connected to the robot controller. When the robot controller outputs a high level, D4 is in the off state, and Ko4 outputs a high level; when the controller outputs a low level, D4 is on, and Ko4 outputs a low level. The I / O module of the microcontroller U2 can control the start and stop of the magnetic detector by detecting the level state of the Ko4 port.

[0087] In this implementation, Figure 10 This is a schematic diagram of the magnetic field control principle of a magnetic detector. When the battery voltage Vbat decreases or the resistance of the yoke winding changes, causing a disturbance in the system, the magnetic field strength of the magnetic detector changes. The control circuit uses linear Hall sensors U8 and U10 to detect the magnetic field changes in real time and adjusts the duty cycle of the SPWM signal accordingly to control the current flowing through windings AB and CD, thereby restoring the magnetic field strength to its original level.

[0088] Example 2:

[0089] Please see Figure 11 Based on the above embodiments, this invention also provides a method for controlling a constant magnetic field in a robot magnetic detector, comprising the following steps:

[0090] S1. The control circuit detects the start signal at the Ki1 terminal of the switching diode D4, and the magnetic detector starts working and lights up the light-emitting diode D1.

[0091] S2. After startup, the controller synchronously monitors multiple operating parameters of the magnetic detector in real time and controls the magnetic field generated by the magnetic detector:

[0092] S3. The temperature of the magnetic yoke winding is collected by thermistors RT1 and RT2. If the temperature is abnormal, the light-emitting diode D2 is lit.

[0093] S4. Determine the battery power level through the battery power detection unit. If the power level is sufficient, light up LED D3.

[0094] S5. The magnetic field generated by the cross yoke is detected by linear Hall sensor U8 and linear Hall sensor U10. The magnetic field strength is kept constant by controlling the magnitude of the current flowing through winding AB and winding CD.

[0095] S6. When the control circuit detects the stop signal at the Ki1 terminal, the magnetic detector stops working and turns off LEDs D1, D2, and D3.

[0096] The solution in this embodiment can be selectively combined with solutions in other embodiments.

[0097] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of this invention. Therefore, any changes and modifications made to the embodiments described herein based on the innovative concept of this invention, or equivalent structural, procedural, or functional transformations made using the description and drawings of this invention, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of protection of this invention.

Claims

1. A constant magnetic field control system for a robot magnetic detector, characterized in that: It includes a control circuit, a power supply circuit, a magnetic yoke winding drive circuit, a magnetic yoke winding current detection circuit, a magnetic yoke winding temperature detection circuit, a magnetic field detection circuit, and a switch signal input / output circuit. It also includes a cross yoke, which includes a first yoke (1), a second yoke (2), windings AB and CD, thermistors RT1 and RT2, a linear Hall sensor U8 and a linear Hall sensor U10. The first magnetic yoke (1) and the second magnetic yoke (2) are arranged independently and crosswise. The winding AB is wound on the first magnetic yoke (1), and the winding CD is wound on the second magnetic yoke (2). The two windings are powered independently and the current magnitude and phase of each winding are controlled independently. Thermistors RT1 and RT2 are respectively installed at the bottom of the windings of the two magnetic yokes, and the linear Hall sensors U8 and U10 are respectively installed on the sides of the two magnetic yokes near the bottom.

2. The constant magnetic field control system for a robot magnetic detector according to claim 1, characterized in that: The control circuit includes a microcontroller U2 and an H-bridge driver chip U3, wherein the microcontroller U2 includes a central processing unit, an SPWM module, an ADC module, and an IO module; The SPWM module is connected to the yoke winding drive circuit through the H-bridge driver chip U3. The ADC module is connected to the battery power detection unit, yoke winding current detection circuit, yoke winding temperature detection circuit and magnetic field detection circuit in the power supply circuit. The IO module is connected to the switch signal input and output circuit.

3. The constant magnetic field control system for a robot magnetic detector according to claim 1, characterized in that: The power supply circuit includes a battery, a π-type filter unit consisting of an inductor L5 and capacitors C9 and C10, a step-down chip U1, a battery power detection unit, and isolation devices for the high-voltage side and the low-voltage side ground lines. The battery is filtered by a π-type filter unit and then supplies power to the high-voltage side on one side, and to the low-voltage side after being stepped down by a step-down chip U1 on the other side. The power supply circuit has four external ports, namely Vbat, VCC, PGND and GND. Vbat is the positive terminal of the high voltage side, PGND is the ground of the high voltage side, VCC is the positive terminal of the low voltage side, and PGND is the ground of the low voltage side. The PGND and GND terminals are connected by an isolation device to reduce mutual interference between the high-voltage side and the low-voltage side. The isolation device is a 0Ω resistor R9, an inductor, a ferrite bead, a section of wire or trace.

4. The constant magnetic field control system for a robot magnetic detector according to claim 1, characterized in that: The two windings are composed of and driven by two independent magnetic yoke winding drive circuits. The two magnetic yoke winding drive circuits have the same structure and parameters, and are composed of MOSFETs Q1, Q2, Q3, Q4, sampling resistors RS1 and RS2, resistors R1, R2, R3, and R4, and capacitors C1, C2, C3, and C4. In the magnetic yoke winding drive circuit, each drive circuit has four groups of MOS transistors, which form an H-bridge circuit to supply power to the magnetic yoke winding; the sampling resistor is located in the lower arm of the H-bridge and is used to detect the current flowing through the magnetic yoke winding; the resistor and capacitor form a first-order RC filter circuit, which is connected between the output terminal of the H-bridge drive chip U3 and the gate of the MOS transistor to enhance the anti-interference capability of the MOS transistor when it is working.

5. A constant magnetic field control system for a robot magnetic detector according to claim 1, characterized in that: The two windings are detected by two independent magnetic yoke winding current detection circuits, and the current flowing through the two windings is measured independently. The two magnetic yoke winding current detection circuits have the same structure and parameters, and are composed of operational amplifier U4, operational amplifier U5, resistors R12, R13, R14, R15, R16, R17, R18, capacitors C14, C15, C16 and C17. In the yoke winding current detection circuit, the operational amplifier and resistors form a forward amplifier circuit to amplify the signals collected by sampling resistors RS1 and RS2; the resistors and capacitors form a first-order RC filter circuit, which is connected to the non-inverting input and inverting input of the operational amplifier, respectively, to filter out interference signals coupled in by the current sampling resistors and signal traces.

6. A constant magnetic field control system for a robot magnetic detector according to claim 1, characterized in that: The two windings are detected by two independent magnetic yoke winding temperature detection circuits. The temperature of the magnetic yoke winding is determined by detecting the resistance values ​​of thermistors RT1 and RT2, respectively. The two magnetic yoke winding temperature detection circuits have the same structure and parameters, and are composed of operational amplifier U6, operational amplifier U7, thermistors RT1 and RT2, resistors R18, R19, R20, R21, R22, R23, capacitors C18 and C19. In the magnetic yoke winding temperature detection circuit, the operational amplifier and the resistor form a voltage follower, which plays the role of impedance transformation. Resistors R19 and R22 are also provided between the thermistor and the low-voltage side ground line to block the coupling interference from the thermistor and its signal trace, so as to avoid it from affecting the low-voltage side ground line.

7. A constant magnetic field control system for a robot magnetic detector according to claim 1, characterized in that: The magnetic field generated by the two magnetic yokes is detected by two independent magnetic field detection circuits. The magnetic field generated by the cross magnetic yokes is detected by linear Hall sensor U8 and linear Hall sensor U10. The two magnetic field detection circuits have the same structure and parameters, and are composed of operational amplifier U9, operational amplifier U11, resistor R26, resistor R27, resistor R28, resistor R29, resistor R30, resistor R31, capacitor C21 and capacitor C22. In the magnetic field detection circuit, the operational amplifier and the resistor form a positive amplification circuit, and the resistor and capacitor form a first-order RC filter circuit connected to the positive input terminal of the operational amplifier.

8. A constant magnetic field control system for a robot magnetic detector according to claim 1, characterized in that: The switching signal input / output circuit includes LED D1, LED D2, LED D3, switching diode D4, resistor R32, resistor R33, resistor R34, resistor R35, and resistor R36. In the switch signal input / output circuit, the three light-emitting diodes are used to display the working status, fault status, and battery power status of the magnetic detector, respectively. The negative terminal of the switch diode D4 is connected to the robot controller. When the robot controller outputs a high level, the switch diode D4 is cut off; when the robot controller outputs a low level, the switch diode D4 is turned on, transmitting the control signal of the robot controller to the control circuit to control the start and stop of the magnetic detector.

9. A method for controlling a constant magnetic field in a magnetic detector for robots, characterized in that, Includes the following steps: S1. The control circuit detects the start signal at the Ki1 terminal of the switching diode D4, and the magnetic detector starts working and lights up the light-emitting diode D1. S2. After startup, the controller synchronously monitors multiple operating parameters of the magnetic detector in real time and controls the magnetic field generated by the magnetic detector: S3. The temperature of the magnetic yoke winding is collected by thermistors RT1 and RT2. If the temperature is abnormal, the light-emitting diode D2 is lit. S4. Determine the battery power level through the battery power detection unit. If the power level is sufficient, light up LED D3. S5. The magnetic field generated by the cross yoke is detected by linear Hall sensor U8 and linear Hall sensor U10. The magnetic field strength is kept constant by controlling the magnitude of the current flowing through winding AB and winding CD. S6. When the control circuit detects the stop signal at the Ki1 terminal, the magnetic detector stops working and turns off LEDs D1, D2, and D3.

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