Torque control device and method of power transmission tower bolt fastening wrench

Abstract

The invention discloses a torque control device and method for a power transmission tower bolt fastening wrench, and belongs to the technical field of bolt fixation. The torque control device comprises a single-chip microcomputer, and a key, a display screen, a Bluetooth module, a GPS positioning module, a wireless communication module, a height detection module, a Hall rotating speed sensor and a current sampling module which are connected with the single-chip microcomputer; wherein the Hall rotating speed sensor is arranged around a driving motor of the bolt fastening wrench, collects a position signal and inputs the position signal into the single-chip microcomputer for rotating speed calculation; the current sampling module is connected with a three-phase full-bridge circuit of the driving motor, current sampling data is input into the single-chip microcomputer after A / D conversion, and control over an outer ring of the driving motor is achieved through the PID controller. The single-chip microcomputer is connected with the three-phase full-bridge circuit for PWM adjustment and steering control of the driving motor, model prediction control of an inner ring is achieved, and torque control of the bolt fastening wrench is achieved by combining control over the outer ring and the inner ring of the wrench driving motor. The output torque of the wrench can be accurately controlled.

Description

Technical Field

[0001] The invention relates to a torque control device of a transmission tower bolt tightening wrench and a torque control method of the transmission tower bolt tightening wrench, belonging to the technical field of bolt fixing. Background Art

[0002] During the erection and maintenance of power transmission towers, the stability of the tower structure is crucial to the safety of the entire power network. The mechanical fastening quality of the tower erection, especially the bolts, directly affects the stability and service life of the transmission tower. In actual operation, bolt tightening operations face many challenges, especially the "under-tightening" and "over-tightening" problems, which can cause the mechanical connection of the bolts to loosen or be over-tightened, which may damage the mechanical structure and even cause the equipment to be scrapped, affecting the safety of the entire power transmission.

[0003] Existing bolt tightening usually relies on manual operation or simple mechanical wrenches. However, traditional manually operated wrenches have great deficiencies in high torque output and control accuracy, and it is difficult to meet the high-precision requirements for bolt tightening during the construction of transmission towers. In addition, traditional torque control systems mostly rely on torque sensors, which collect data from torque sensors and then monitor and adjust the torque. The solution is complicated and the torque control is not precise enough. Summary of the invention

[0004] The purpose of the present invention is to address the technical problems mentioned in the above background technology and propose a torque control device and method for a transmission tower bolt tightening wrench, which directly adjusts the dynamic performance of the motor by real-time monitoring of the motor's speed and current signal, and then accurately controls the output torque of the wrench to ensure the accuracy of bolt tightening. The specific technical solution is as follows:

[0005] A torque control device for a transmission tower bolt tightening wrench comprises a single chip microcomputer and a key connected to the single chip microcomputer, a display screen, a Bluetooth module, a GPS positioning module, a wireless communication module, a height detection module, a Hall speed sensor, and a current sampling module, wherein the Hall speed sensor is arranged around a driving motor of the bolt tightening wrench to collect position signals and input the signals into the single chip microcomputer for speed calculation; the current sampling module is connected to a three-phase full-bridge circuit of the driving motor, and inputs the current sampling data into the single chip microcomputer after A / D conversion, and controls the outer loop of the driving motor through a PID controller; the single chip microcomputer is connected to the three-phase full-bridge circuit to perform PWM regulation and steering control of the driving motor, and realizes the model predictive control (MPC) of the inner loop, and realizes the torque control of the bolt tightening wrench by combining the outer loop and inner loop control of the wrench driving motor.

[0006] Furthermore, the Bluetooth module and the wireless communication module are used for remote monitoring and communication with a host computer, and the GPS positioning module and the altitude detection module are used for geographical positioning of the device.

[0007] Furthermore, the single-chip computer includes a microprocessor, a display circuit and a key circuit. The key circuit is connected to the key for inputting preset torque and speed; the display circuit is connected to the display screen for displaying settings and operating conditions; the microprocessor calculates and adjusts the speed according to the data transmitted by the Hall speed sensor, and performs PWM adjustment and steering control according to the set speed, and adjusts the current according to the data transmitted by the current sampling module and the speed condition data.

[0008] Furthermore, the microcontroller model is STM32F407, the current sensor model is BJHCS-LSP, and the Hall speed sensor model is SJ1092H.

[0009] A method for controlling the torque of a transmission tower bolt tightening wrench adopts the above device and performs the following steps:

[0010] Step 1: Convert the relationship between the output torque of the wrench and the load torque of the bolt tightening into the relationship between the load current corresponding to the load torque and the motor armature current and motor speed, and establish a mathematical model: Among them, I L is the load current corresponding to the load torque, La is the motor armature current corresponding to the output motor corresponding to the output torque, Tm is the electromechanical time constant, Ce is the electromotive force coefficient at the rated flux, R is the armature resistance, n is the motor speed, and t is the time;

[0011] Step 2: Use the model predictive controller (MPC) as the speed regulator of the inner loop of the drive motor, use the PID controller as the current regulation loop of the outer loop of the drive motor, use the current sensor and the Hall speed sensor to collect the current and speed of the motor during rotation, use the Hall sensor to collect the motor speed n, and feed it back to the outer loop PID controller. Use the current sensor (such as current transformer) to collect the armature current Ia and feed it back to the inner loop MPC controller;

[0012] Step 3: According to the model predictive control rule, set the prediction time domain N, control time domain, cost function weight, constraint conditions, and control increment limit. These parameters are used for current control, and use the QP solver (OSQP) for optimization and solution; the PID outer loop is used to adjust the motor speed n, that is, to indirectly control the current and torque by controlling the speed, and adjust the PID gain parameter K p , K i and K d To obtain the desired dynamic response;

[0013] Step 4: Collect the dynamic response curves of the speed, current and load torque during system operation to perform torque control of the bolt tightening wrench.

[0014] Furthermore, in step 2, a model predictive controller is used to adjust the speed of the motor. The outer loop control uses the system's speed regulation loop ASR. The actual speed n of the motor is collected through a Hall speed sensor and fed back to the speed regulation loop ASR. The current sensor TA is used to collect the load current IL of the motor and feed it back to the current regulation loop ACR. The current sensor and the Hall speed sensor monitor the operating status of the motor in real time and ensure the stability of the system speed.

[0015] Furthermore, in step 2, a PID controller is used to control the current regulation loop ACR as an inner loop control. First, the target speed n* of the motor is given, and the control of the outer speed regulation loop ASR is realized by a fuzzy PID controller. The output current Ia of the regulator is used as the input of the current regulation loop ACR. The output of the current regulation loop is used to control the PWM wave generation module UPW. The PWM wave signal generated by the UPW module controls the H-bridge circuit UPEM through the drive circuit module GD, thereby realizing motor speed regulation and controlling the motor current, and finally accurately controlling the motor torque output, wherein the given speed n*, the motor armature current Ia, the feedback speed n and the load current IL are all digital signals.

[0016] Furthermore, the MPC inner loop in step 3 is used to accurately control the current to achieve the target torque. The prediction time domain N is selected according to the dynamic characteristics of the system. N is between 10 and 20 time steps. The control time domain takes M = 1, that is, only one control input is calculated each time to reduce the amount of calculation. The cost function of MPC is defined as: Where Ia(k) is the motor armature current at step k, Ia_ref is the target current set by the PID outer loop, λ is the weight factor of the control increment, ΔI a (k) represents the current change; and according to the physical limitations of the motor, the following constraints are imposed: Current constraint: I min ≤I a ≤I max , control increment constraint: |ΔI a ∣≤ΔI max ; In each control cycle, the optimization algorithm is used to solve the MPC optimization problem and obtain the optimal control input I a and apply it to the system.

[0017] Furthermore, in step 3, the PID outer loop is used to adjust the motor speed n, that is, to indirectly control the current and torque by controlling the speed. By setting the target speed n*, the error e=n*-n between the actual speed and the expected speed is calculated. The output current target value Ia_ref is calculated using the PID formula as the target current of the inner loop MPC to ensure that the motor can still track the expected speed when the load changes. And by adjusting the PID gain parameters Kp, Ki and Kd to obtain the desired dynamic response. The output Ia_ref generated by the outer loop PID controller. Beneficial effects:

[0018] 1) The present invention directly adjusts the dynamic performance of the motor by real-time monitoring of the motor's rotation speed and current signal, thereby accurately controlling the output torque, ensuring the reliability of bolt tightening, avoiding "under-tightening" and "over-tightening" phenomena, and improving the safety performance of the transmission tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the device of the present invention;

[0020] Figure 2 It is a schematic diagram of a control system of the present invention;

[0021] Figure 3 It is a schematic diagram of the structure of the PID outer loop and the MPC inner loop in the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below in conjunction with specific illustrations and embodiments.

[0023] like Figure 1 As shown, a torque control device for a transmission tower bolt tightening wrench includes a single-chip microcomputer and a button connected to the single-chip microcomputer, a display screen, a Bluetooth module, a GPS positioning module, a wireless communication module, a height detection module, a Hall speed sensor, and a current sampling module, wherein the Hall speed sensor is arranged around the driving motor of the bolt tightening wrench, collects position signals and inputs them into the single-chip microcomputer for speed calculation; the current sampling module is connected to the three-phase full-bridge circuit of the driving motor, and inputs the current sampling data into the single-chip microcomputer after A / D conversion, and realizes the control of the outer loop of the driving motor through the PID controller; the single-chip microcomputer is connected to the three-phase full-bridge circuit to perform PWM regulation and steering control of the driving motor, realizes the model predictive control (MPC) of the inner loop, and realizes the torque control of the bolt tightening wrench by combining the outer loop and inner loop control of the wrench driving motor, the Bluetooth module and the wireless communication module are used for remote monitoring and communication with the host computer, and the GPS positioning module and the height detection module are used for geographical positioning of the device.

[0024] The single-chip computer includes a microprocessor, a display circuit and a key circuit. The key circuit is connected to the key for inputting preset torque and speed. The display circuit is connected to the display screen for displaying settings and operating conditions. The microprocessor calculates and adjusts the speed according to the data from the Hall speed sensor, and performs PWM adjustment and steering control according to the set speed. It adjusts the current according to the data from the current sampling module and the speed condition data. The single-chip computer model is STM32F407, the current sensor model is BJHCS-LSP, and the Hall speed sensor model is SJ1092H.

[0025] A method for controlling the torque of a transmission tower bolt tightening wrench adopts the above device and performs the following steps:

[0026] Step 1: Convert the relationship between the output torque of the wrench and the load torque of the bolt tightening into the relationship between the load current corresponding to the load torque and the motor armature current and motor speed, and establish a mathematical model: Among them, I L is the load current corresponding to the load torque, La is the motor armature current corresponding to the output motor corresponding to the output torque, Tm is the electromechanical time constant, Ce is the electromotive force coefficient at the rated flux, R is the armature resistance, n is the motor speed, and t is the time;

[0027] Step 2: Use the model predictive controller (MPC) as the speed regulator of the inner loop of the drive motor, and use the PID controller as the current regulation loop of the outer loop of the drive motor. Use the current sensor and the Hall speed sensor to collect the current and speed of the motor during rotation. Use the Hall sensor to collect the motor speed n and feed it back to the outer loop PID controller. A current sensor (such as a current transformer) is used to collect the armature current Ia and feed it back to the inner loop MPC controller; a model predictive controller is used to adjust the speed of the motor, and the outer loop control uses the system's speed regulation loop ASR. The actual speed n of the motor is collected through a Hall speed sensor and fed back to the speed regulation loop ASR. The current sensor TA is used to collect the load current IL of the motor and feed it back to the current regulation loop ACR. The current sensor and the Hall speed sensor monitor the running state of the motor in real time and ensure the stability of the system speed; a PID controller is used to control the current regulation loop ACR as the inner loop control. First, the target speed n* of the motor is given, and the control of the outer loop speed regulation loop ASR is realized through a fuzzy PID controller. The output current Ia of the regulator is used as the input of the current regulation loop ACR. The output of the current regulation loop is used to control the PWM wave generation module UPW. The PWM wave signal generated by the UPW module controls the H-bridge circuit UPEM through the drive circuit module GD, thereby realizing motor speed regulation and controlling the motor current, and finally accurately controlling the motor torque output, wherein the given speed n*, the motor armature current Ia, the feedback speed n and the load current IL are all digital signals;

[0028] Step 3: According to the model predictive control rule, set the prediction time domain N, control time domain, cost function weight, constraint conditions, and control increment limit. These parameters are used for current control, and use the QP solver (OSQP) for optimization and solution; the PID outer loop is used to adjust the motor speed n, that is, to indirectly control the current and torque by controlling the speed, and adjust the PID gain parameter K p , K i and K d To obtain the desired dynamic response; the MPC inner loop is used to accurately control the current to achieve the target torque. The prediction time domain N is selected according to the dynamic characteristics of the system. N is between 10 and 20 time steps. The control time domain takes M = 1, that is, only one control input is calculated each time to reduce the amount of calculation. The cost function of MPC is defined as: Where Ia(k) is the motor armature current at step k, Ia_ref is the target current set by the PID outer loop, λ is the weight factor of the control increment, ΔI a (k) represents the current change; and according to the physical limitations of the motor, the following constraints are imposed: Current constraint: I min ≤I a ≤I max , control increment constraint: |ΔI a ∣≤ΔI max ; In each control cycle, the optimization algorithm is used to solve the MPC optimization problem and obtain the optimal control input I a , and apply it to the system; the PID outer loop is used to adjust the motor speed n, that is, to indirectly control the current and torque by controlling the speed. By setting the target speed n*, the error e=n*-n between the actual speed and the expected speed is calculated. The output current target value Ia_ref is calculated using the PID formula as the target current of the inner loop MPC to ensure that the motor can still track the expected speed when the load changes. And by adjusting the PID gain parameters Kp, Ki and Kd to obtain the desired dynamic response. The output Ia_ref generated by the outer loop PID controller;

[0029] Step 4: Collect the dynamic response curves of the speed, current and load torque during system operation to perform torque control of the bolt tightening wrench.

[0030] Embodiment: Before tightening the bolts of a transmission tower bolt tightening wrench, the user first sets a target torque value in the "torque preset" link of the torque control device, and then starts or stops the motor operation through the "button control", and then the "given speed" gives an initial rotation speed instruction according to the user's needs.

[0031] When the "speed calculation" starts working, it uses the actual feedback information obtained from the "drive motor" and the previously set target torque value to perform real-time calculations to determine what actions should be taken at the moment to make the actual torque close to the expected value.

[0032] After receiving the calculation results, the "PWM regulation and commutation control" sends a series of pulse width modulation signals to adjust the switch state of the "three-phase full-bridge circuit", thereby changing the voltage and polarity applied to the motor, and ultimately achieving the purpose of accurately controlling its rotation speed. At the same time, the "current regulation" is also continuously monitoring whether the current intensity flowing through the armature winding meets the requirements. If the deviation is found to be too large, measures will be taken immediately to correct it to ensure the stability and efficiency of the overall system.

[0033] Finally, the "display circuit" summarizes the key data generated in the above process and displays it to the user through the LCD display, so that the user can grasp the latest developments at any time and respond in time. In addition, the "Bluetooth module" and "wireless communication module" enable the torque control device to remotely connect to the host computer, which is convenient for users to remotely control. The "GPS positioning module" and "height detection module" can provide geographic positioning services for the torque control device, further enhancing the functionality and flexibility of the entire device.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the principles and spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A torque control device for a transmission tower bolt tightening wrench, characterized in that: It includes a single-chip microcomputer and buttons, a display screen, a Bluetooth module, a GPS positioning module, a wireless communication module, a height detection module, a Hall speed sensor, and a current sampling module connected to the single-chip microcomputer. The Hall speed sensor is arranged around the driving motor of the bolt tightening wrench to collect position signals and input them into the single-chip microcomputer for speed calculation; the current sampling module is connected to the three-phase full-bridge circuit of the driving motor, and the current sampling data is input into the single-chip microcomputer after A / D conversion, and the outer loop of the driving motor is controlled by the PID controller; The single-chip microcomputer is connected to the three-phase full-bridge circuit to perform PWM regulation and steering control of the drive motor, realize the inner loop model predictive control, and combine the outer loop and inner loop control of the wrench drive motor to realize the torque control of the bolt tightening wrench.

2. The torque control device for the transmission tower bolt tightening wrench according to claim 1, characterized in that: The Bluetooth module and the wireless communication module are used for remote monitoring and communication with a host computer, and the GPS positioning module and the height detection module are used for geographical positioning of the device.

3. The torque control device for the transmission tower bolt tightening wrench according to claim 1, characterized in that: The single chip microcomputer includes a microprocessor, a display circuit and a key circuit. The key circuit is connected to the key and is used to input the preset torque and speed; the display circuit is connected to the display screen and is used to display the settings and operating conditions; the microprocessor calculates and adjusts the speed according to the data transmitted by the Hall speed sensor, and performs PWM adjustment and steering control according to the set speed, and adjusts the current according to the data transmitted by the current sampling module and the speed condition data.

4. The torque control device for the transmission tower bolt tightening wrench according to claim 3, characterized in that: The single chip microcomputer model is STM32F407, the current sensor model is BJHCS-LSP, and the Hall speed sensor model is SJ1092H.

5. A torque control method for a transmission tower bolt tightening wrench, characterized in that: Using the device according to any one of claims 1 to 4, and performing the following steps: Step 1: Convert the relationship between the output torque of the wrench and the load torque of the bolt tightening into the relationship between the load current corresponding to the load torque and the motor armature current and motor speed, and establish a mathematical model: , where IL is the load current corresponding to the load torque, La is the motor armature current corresponding to the output motor corresponding to the output torque, Tm is the electromechanical time constant, Ce is the electromotive force coefficient under the rated magnetic flux, R is the armature resistance, n is the motor speed, and t is the time; Step 2: Use the model predictive controller as the speed regulator of the inner loop of the drive motor, use the PID controller as the current regulation loop of the outer loop of the drive motor, use the current sensor and the Hall speed sensor to collect the current and speed of the motor during rotation, use the Hall sensor to collect the motor speed n, and feed it back to the outer loop PID controller. Use the current sensor (such as current transformer) to collect the armature current Ia and feed it back to the inner loop MPC controller; Step 3: According to the model predictive control rule, the prediction time domain N, control time domain, cost function weight, constraint conditions, and control increment limit are set for current control, and the QP solver is used for optimization and solution; the PID outer loop is used to adjust the motor speed n, that is, to indirectly control the current and torque by controlling the speed, and the desired dynamic response is obtained by adjusting the PID gain parameters Kp, Ki, and Kd; Step 4: Collect the dynamic response curves of the speed, current and load torque during system operation to perform torque control of the bolt tightening wrench.

6. The torque control method of the transmission tower bolt tightening wrench according to claim 5, characterized in that: In step 2, a model predictive controller is used to adjust the speed of the motor. The outer loop control uses the system's speed regulation loop ASR. The actual speed n of the motor is collected through the Hall speed sensor and fed back to the speed regulation loop ASR. The current sensor TA is used to collect the load current IL of the motor and feed it back to the current regulation loop ACR. The current sensor and the Hall speed sensor monitor the running status of the motor in real time and ensure the stability of the system speed.

7. The torque control method of the transmission tower bolt tightening wrench according to claim 5, characterized in that: In step 2, a PID controller is used to control the current regulation loop ACR as the inner loop control. First, the target speed n* of the motor is given, and the outer speed regulation loop ASR is controlled by a fuzzy PID controller. The output current Ia of the regulator is used as the input of the current regulation loop ACR. The output of the current regulation loop is used to control the PWM wave generation module UPW. The PWM wave signal generated by the UPW module controls the H-bridge circuit UPEM through the drive circuit module GD, thereby realizing motor speed regulation and controlling the motor current, and finally accurately controlling the motor torque output. The given speed n*, the motor armature current Ia, the feedback speed n and the load current IL are all digital signals.

8. The torque control method of the transmission tower bolt tightening wrench according to claim 5, characterized in that: The MPC inner loop in step 3 is used to accurately control the current to achieve the target torque. The prediction time domain N is selected according to the dynamic characteristics of the system. N is between 10 and 20 time steps. The control time domain takes M = 1, that is, only one control input is calculated each time to reduce the amount of calculation. The cost function of MPC is defined as: Where Ia(k) is the motor armature current at step k, Ia_ref is the target current set by the PID outer loop, λ is the weight factor of the control increment, ΔI a (k) represents the current change; and according to the physical limitations of the motor, the following constraints are imposed: Current constraint: I min ≤I a ≤I max , control increment constraint: |ΔI a ∣≤ΔI max ; In each control cycle, the optimization algorithm is used to solve the MPC optimization problem and obtain the optimal control input I a and apply it to the system.

9. The torque control method of the transmission tower bolt tightening wrench according to claim 5, characterized in that: In step 3, the PID outer loop is used to adjust the motor speed n, that is, to indirectly control the current and torque by controlling the speed. By setting the target speed n*, the error e=n*-n between the actual speed and the expected speed is calculated. The output current target value Ia_ref is calculated using the PID formula as the target current of the inner loop MPC to ensure that the motor can still track the expected speed when the load changes. And the desired dynamic response is obtained by adjusting the PID gain parameters Kp, Ki and Kd. The output Ia_ref generated by the outer loop PID controller.

Images