A sludge drying rake device and control method

Abstract

The present application relates to the technical field of equipment, and especially relates to a sludge drying rake tooth device and a control method, which comprises a data receiving module receiving original electric signals and converting the original electric signals into digital electric signal sequences, from which deformation characteristic data and real-time torque data are separated; a resistance evaluation module obtaining the separated data and calculating instantaneous mechanical resistance values, and then constructing a resistance evaluation data model; an instruction generating module obtaining the instantaneous mechanical resistance values and comparing the instantaneous mechanical resistance values with a safety resistance threshold value, calculating load compensation characteristics when determining that the instantaneous mechanical resistance values are greater than the safety resistance threshold value, and generating a dynamic adjustment instruction and sending the dynamic adjustment instruction to the driving motor to drive the driving motor to increase motor output torque. The present application realizes dynamic torque adjustment when resistance fluctuation is caused by sludge viscosity mutation, and effectively reduces the probability of mechanical fatigue damage of transmission components.

Description

Technical Field

[0001] This invention relates to the field of equipment control technology, and in particular to a sludge drying rake tooth device and control method. Background Technology

[0002] In the application scenario of the adaptive operation control technology of the rake teeth in the vertical disc sludge drying and granulation equipment, the vertical disc sludge drying and granulation equipment belongs to an environmentally friendly equipment that combines indirect heating and multi-disc drying. The drying chamber of the vertical disc sludge drying and granulation equipment consists of a series of vertically arranged and horizontally placed discs, and the main shaft located at the center of the chamber rotates continuously under the drive of a motor. The main shaft, together with the rake arms and rake blades fixed on the main shaft, rotates synchronously, so that the sludge is continuously turned over and heated under the mechanical action of the rotating rake blades.

[0003] When the sludge moisture content is between 40% and 60%, it enters the plastic stage, making it highly prone to agglomeration. Sludge in the plastic stage exhibits high surface adhesion and fluid physical properties, while its internal composition contains a large amount of organic matter, resulting in extremely strong viscosity. During the physical drying process, the sludge viscosity undergoes drastic changes, and the mechanical friction generated by these viscosity fluctuations directly acts on the rotating rake blades and arms.

[0004] Existing control methods for sludge drying rake tooth devices generally employ fixed-parameter operation modes, and existing control systems lack adaptive control models that adapt to the equipment's operating conditions. Viscosity changes during the drying process cause unpredictable fluctuations in the physical resistance of the rake teeth, directly altering the mechanical load on the drive motor. Because conventional control systems cannot acquire and analyze resistance change data in real time, constant-parameter control mechanisms cannot dynamically adjust the motor's output speed and drive torque based on real-time load conditions. Fixed operating modes easily lead to mechanical fatigue in moving parts, and may even cause mechanical failures such as overload shutdowns. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a sludge drying rake tooth device and control method. This invention solves the technical problem that the resistance fluctuation of the rake teeth caused by viscosity changes during sludge drying prevents the equipment from adaptively adjusting the drive parameters.

[0006] To solve the above-mentioned technical problems, the specific contents of the present invention are as follows: In a first aspect, the present invention provides a sludge drying rake tooth device, comprising a mechanical body and a control system, wherein the mechanical body comprises a drying chamber, a central main shaft, a rake arm, a spring rake tooth assembly, and a drive motor. The central main shaft is arranged vertically inside the drying chamber. The rake arm, which is horizontally extended, is fixedly connected to the outer wall of the central main shaft. The spring rake tooth assembly is installed at the end of the rake arm away from the central main shaft. The spring rake tooth assembly includes an elastic buffer and a rake blade. The two ends of the elastic buffer are fixedly connected to the rake arm and the rake blade, respectively. The central main shaft is connected to the drive motor for transmission. A torque detection element is installed at the power output end of the drive motor, and a strain detection element is fitted onto the surface of the elastic buffer; the mechanical body establishes a communication connection with the control system; the control system includes a data receiving module, a resistance evaluation module, and an instruction generation module; The data receiving module receives the raw electrical signals transmitted by the torque detection element and the strain detection element, converts the raw electrical signals into a digital electrical signal sequence, and separates the deformation characteristic data and real-time torque data from the digital electrical signal sequence. The resistance assessment module acquires the deformation characteristic data and the real-time torque data, uses the deformation characteristic data to calculate the instantaneous mechanical resistance value, and then constructs a resistance assessment data model including the instantaneous mechanical resistance value and the real-time torque data. The instruction generation module obtains the instantaneous mechanical resistance value output by the resistance assessment data model, compares the instantaneous mechanical resistance value with a preset safety resistance threshold, and when it is determined that the instantaneous mechanical resistance value is greater than the safety resistance threshold, the instruction generation module calculates the load compensation characteristics and generates a dynamic adjustment instruction, and sends the dynamic adjustment instruction to the drive motor to drive the drive motor to increase the motor output torque.

[0007] Furthermore, in the sludge drying rake tooth device of the present invention, the data receiving module includes an analog-to-digital conversion unit and a high-frequency filtering unit; The analog-to-digital conversion unit receives the original electrical signal and converts the original electrical signal into the digital electrical signal sequence; The high-frequency filtering unit filters the digital electrical signal sequence according to a preset low-pass filter cutoff frequency, separates the deformation characteristic data and the real-time torque data located below the low-pass filter cutoff frequency, and sends the deformation characteristic data and the real-time torque data to the resistance evaluation module.

[0008] Furthermore, in the sludge drying rake tooth device of the present invention, the elastic buffer adopts a helical compression spring structure, and the strain detection element is attached along the axial force direction of the helical compression spring structure. The resistance assessment module acquires the deformation displacement values ​​included in the deformation characteristic data, calls the preset spring stiffness coefficient to multiply the deformation displacement values, and calculates the instantaneous mechanical resistance value.

[0009] Furthermore, in the sludge drying rake tooth device of the present invention, the resistance assessment module includes a data alignment unit and a model building unit; The data alignment unit acquires the real-time torque data and assigns a consistent time identifier to the real-time torque data and the instantaneous mechanical resistance value; The model building unit establishes a mapping correlation matrix between the instantaneous mechanical resistance value and the real-time torque data based on the time identifier, and outputs the mapping correlation matrix as the resistance evaluation data model.

[0010] Furthermore, in the sludge drying rake tooth device of the present invention, the instruction generation module includes a numerical comparison unit and a parameter calculation unit; The numerical comparison unit extracts the instantaneous mechanical resistance value output by the resistance assessment data model according to the set time step, and subtracts the safety resistance threshold from the instantaneous mechanical resistance value to output the resistance fluctuation difference. When the resistance fluctuation difference is determined to be greater than zero, the numerical comparison unit sends the high load status identifier and the resistance fluctuation difference to the parameter calculation unit.

[0011] Furthermore, in the sludge drying rake tooth device of the present invention, the parameter calculation unit receives the high load state indicator and the resistance fluctuation difference, and starts the proportional-integral-derivative control algorithm. The parameter calculation unit inputs the resistance fluctuation difference into the proportional integral derivative control algorithm for calculation, and outputs a frequency reduction and torque increase parameter matrix including the frequency reduction magnitude and torque increase ratio. The parameter calculation unit generates the dynamic adjustment command according to the frequency reduction and torque increase parameter matrix. The dynamic adjustment command includes the frequency reduction magnitude and the torque increase ratio.

[0012] Furthermore, in the sludge drying rake tooth device of the present invention, the drive motor is connected to a frequency converter drive assembly. The variable frequency drive component receives the dynamic adjustment command, converts the frequency reduction magnitude included in the dynamic adjustment command into a stator voltage frequency control signal, and converts the torque increase ratio included in the dynamic adjustment command into a stator current amplitude control signal. The drive motor reduces its speed according to the stator voltage frequency control signal and increases its output torque according to the stator current amplitude control signal.

[0013] Furthermore, in the sludge drying rake tooth device of the present invention, the control system further includes a state recovery module; The numerical comparison unit continuously monitors the resistance fluctuation difference. When the resistance fluctuation difference is less than or equal to zero and remains for a set time period, it sends a normal load identifier to the state recovery module. The status recovery module receives the normal load identifier, generates an operation recovery command, and sends the operation recovery command to the frequency converter drive component; The variable frequency drive component sends a reference frequency control signal and a reference current control signal to the drive motor according to the operation recovery command, thereby driving the drive motor to return to the set reference operating state.

[0014] Furthermore, in the sludge drying rake tooth device of the present invention, a heating disc is fixed in the horizontal direction inside the drying chamber; The rake arm, together with the central main shaft, maintains a horizontal state and rotates parallel to the heating disk; The rake blade is located above the heating disk, and the bottom end face of the rake blade maintains a set vertical gap with the upper surface of the heating disk.

[0015] Secondly, the present invention provides a control method for a sludge drying rake tooth device, applied to the sludge drying rake tooth device as described above, comprising: Step 1: The data receiving module receives the raw electrical signals transmitted by the torque detection element and the strain detection element, converts the raw electrical signals into a digital electrical signal sequence, and separates the deformation characteristic data and real-time torque data from the digital electrical signal sequence; Step 2: The resistance assessment module acquires the deformation characteristic data and the real-time torque data, uses the deformation characteristic data to calculate the instantaneous mechanical resistance value, and then constructs a resistance assessment data model that includes the instantaneous mechanical resistance value and the real-time torque data. Step 3: The instruction generation module obtains the instantaneous mechanical resistance value output by the resistance assessment data model, compares the instantaneous mechanical resistance value with the preset safety resistance threshold, and when it is determined that the instantaneous mechanical resistance value is greater than the safety resistance threshold, the instruction generation module calculates the load compensation characteristics and generates a dynamic adjustment instruction, and sends the dynamic adjustment instruction to the drive motor to drive the drive motor to increase the motor output torque.

[0016] Beneficial effects of this invention: This invention provides a sludge drying rake device and control method, overcoming the shortcomings of existing constant parameter control mechanisms, which lack an adaptive control model to suit the equipment's operating conditions, leading to mechanical fatigue of operating components. In the data acquisition and feedback control logic, the torque detection element, along with the strain detection element mounted on the surface of the elastic buffer, operates synchronously and transmits raw electrical signals characterizing the physical stress state to the data receiving module. The resistance assessment module acquires the deformation characteristic data and real-time torque data separated by the data receiving module, calculates the instantaneous mechanical resistance value using the deformation characteristic data, and constructs a resistance assessment data model mapping the transient load fluctuations of the equipment by combining the real-time torque data. The instruction generation module compares the instantaneous mechanical resistance value output by the resistance assessment data model with a set safe resistance threshold. When the instantaneous mechanical resistance value is determined to be greater than the safe resistance threshold, it calculates the load compensation characteristics and generates a dynamic adjustment instruction. The drive motor receives the dynamic adjustment instruction and increases the motor's output torque, enabling the detection element and the calculation control module to form a closed-loop control data chain from resistance characteristic sensing to dynamic torque compensation. The dynamically increased motor output torque offsets the physical viscous frictional resistance generated when the sludge enters the plastic stage, solving the technical problem that the dryer cannot adaptively adjust the drive parameters according to the instantaneous load conditions. This reduces the probability of mechanical fatigue damage to mechanical transmission components such as the rake blades and the central main shaft, and avoids overload shutdown failures caused by physical agglomeration of the dryer. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on the accompanying drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of a control method for a sludge drying rake tooth device according to the present invention. Detailed Implementation

[0019] To make the technical solution of the present invention clearer, the present invention will be clearly and completely described below with reference to specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In a first aspect, the present invention provides a sludge drying rake tooth device, comprising a mechanical body and a control system, wherein the mechanical body comprises a drying chamber, a central main shaft, a rake arm, a spring rake tooth assembly, and a drive motor. The central main shaft is arranged vertically inside the drying chamber. The rake arm, which is horizontally extended, is fixedly connected to the outer wall of the central main shaft. The spring rake tooth assembly is installed at the end of the rake arm away from the central main shaft. The spring rake tooth assembly includes an elastic buffer and a rake blade. The two ends of the elastic buffer are fixedly connected to the rake arm and the rake blade, respectively. The central main shaft is connected to the drive motor for transmission. A torque detection element is installed at the power output end of the drive motor, and a strain detection element is fitted onto the surface of the elastic buffer; the mechanical body establishes a communication connection with the control system; the control system includes a data receiving module, a resistance evaluation module, and an instruction generation module; The data receiving module receives the raw electrical signals transmitted by the torque detection element and the strain detection element, converts the raw electrical signals into a digital electrical signal sequence, and separates the deformation characteristic data and real-time torque data from the digital electrical signal sequence. The resistance assessment module acquires the deformation characteristic data and the real-time torque data, uses the deformation characteristic data to calculate the instantaneous mechanical resistance value, and then constructs a resistance assessment data model including the instantaneous mechanical resistance value and the real-time torque data. The instruction generation module obtains the instantaneous mechanical resistance value output by the resistance assessment data model, compares the instantaneous mechanical resistance value with a preset safety resistance threshold, and when it is determined that the instantaneous mechanical resistance value is greater than the safety resistance threshold, the instruction generation module calculates the load compensation characteristics and generates a dynamic adjustment instruction, and sends the dynamic adjustment instruction to the drive motor to drive the drive motor to increase the motor output torque.

[0021] In the data acquisition phase, a torque sensing element installed at the power output end of the drive motor and a strain sensing element surface-mounted on an elastic buffer simultaneously acquire weak raw electrical signals. The data receiving module within the control system receives these raw electrical signals and performs analog-to-digital conversion, quantizing the continuous analog voltage values ​​into a discrete sequence of digital electrical signals. The data receiving module then analyzes the multi-channel input data, separating out the deformation characteristic data and real-time torque data corresponding to different sensing channels.

[0022] The resistance assessment module extracts deformation characteristic data and uses linear transformation logic to calculate the instantaneous mechanical resistance value. The module combines the instantaneous mechanical resistance value with real-time torque data and stores it in a multi-dimensional array to construct a resistance assessment data model reflecting the transient forces acting on the equipment. The instruction generation module extracts the instantaneous mechanical resistance value output from the resistance assessment data model and compares it with a pre-recorded safety resistance threshold stored in the control system's memory.

[0023] When the computational logic determines that the absolute value of the instantaneous mechanical resistance exceeds the safe resistance threshold, the instruction generation module triggers the overload compensation logic to calculate the load compensation characteristics required to overcome high-load friction. Subsequently, the instruction generation module generates a dynamic adjustment instruction containing given speed and torque parameters and sends the dynamic adjustment instruction to the control input terminal of the drive motor. After receiving the instruction, the drive motor synchronously increases its output torque.

[0024] The data receiving module includes an analog-to-digital converter (ADC) unit and a high-frequency filtering unit. The ADC unit inside the data receiving module receives the original microvolt-level electrical signal at a preset high-frequency sampling rate. A 24-bit high-precision ADC chip is then used to quantize the continuously changing analog signal, converting it into a digital electrical signal sequence composed of amplitude values ​​corresponding to discrete time points.

[0025] The digital electrical signal sequence is transmitted unidirectionally to the high-frequency filtering unit. The high-frequency filtering unit has a preset low-pass filter cutoff frequency, set at a limit of 50 Hz. The high-frequency filtering unit runs a low-pass filtering algorithm to perform convolution filtering on the digital electrical signal sequence, filtering out mechanical vibration interference and electromagnetic high-frequency noise exceeding the low-pass filter cutoff frequency. Through filtering, the high-frequency filtering unit separates the effective deformation characteristic data and real-time torque data below the low-pass filter cutoff frequency, and sends the noise-reduced and purified deformation characteristic data and real-time torque data to the resistance assessment module for subsequent force calculations.

[0026] The spring rake tooth assembly includes an elastic buffer element employing a helical compression spring structure, and the strain detection element is a resistive strain gauge. The resistive strain gauge is surface-mounted along the axial force direction of the helical compression spring structure to sense the microscopic compressive deformation occurring along the central axis of the helical compression spring. After receiving the deformation characteristic data, the resistance assessment module analyzes the micro-strain electrical parameters contained within the deformation characteristic data.

[0027] The resistance assessment module converts the micro-strain electrical parameters into deformation displacement values ​​in standard millimeters based on the calibrated material elastic modulus formula. The module then retrieves the test calibration constants (i.e., spring stiffness coefficients) stored in the control system and calls the arithmetic logic unit to perform a product operation. The arithmetic logic unit directly multiplies the deformation displacement value by the spring stiffness coefficient to obtain the instantaneous mechanical resistance value experienced by the rake blade tip during sludge agitation.

[0028] The resistance assessment module is equipped with a data alignment unit. This unit synchronously acquires real-time torque data and instantaneous mechanical resistance values. Due to microsecond-level delays in signal transmission from different types of sensors, the data alignment unit assigns a completely consistent absolute time identifier to each set of simultaneously acquired real-time torque data and instantaneous mechanical resistance values, following the unified clock source within the control system.

[0029] The model building unit establishes a two-dimensional array arranged in ascending order of time markers. The time markers are used as the first column index, the instantaneous mechanical resistance values ​​as the second column data, and the real-time torque data as the third column data, thus establishing a mapping correlation matrix that strictly corresponds to the time step. The model building unit uses the assembled mapping correlation matrix as the resistance assessment data model and outputs it directly to the next control logic node.

[0030] When the sludge moisture content is between 40% and 60%, it enters the plastic stage, exhibiting extremely strong adhesive properties. The instruction generation module is equipped with a numerical comparison unit. This unit iteratively extracts the instantaneous mechanical resistance values ​​from the last line of the resistance assessment data model, following a set time step of 10 milliseconds. The preset safe resistance threshold in the control system is the maximum safe stress limit set to avoid overload caused by agglomeration during the plastic stage.

[0031] The numerical comparison unit executes a subtraction operation instruction, directly subtracting the safe resistance threshold from the extracted instantaneous mechanical resistance value, and outputs a resistance fluctuation difference value representing the degree of force exceeding the limit. The numerical comparison unit performs a logical judgment on the positive or negative attribute of the resistance fluctuation difference value. When the resistance fluctuation difference value is determined to be greater than zero, it indicates that the sludge adhesion resistance has exceeded the limit of the normal operating range. The numerical comparison unit generates a 1-bit wide high-load status flag and sends the high-load status flag along with the precisely calculated resistance fluctuation difference value to the parameter calculation unit.

[0032] Upon receiving the high-load status indicator and the resistance fluctuation difference, the parameter calculation unit activates the proportional-integral-derivative (PID) control algorithm module. The parameter calculation unit uses the resistance fluctuation difference as the system error input and imports it into the PID module for mathematical calculations. The proportional component of the PID module linearly amplifies the resistance fluctuation difference according to a set amplification factor; the integral component integrates the historical difference over time to eliminate steady-state error; and the derivative component calculates the rate of change of the difference to predict the resistance growth trend.

[0033] The proportional-integral-derivative (PID) control algorithm module performs cumulative summation calculations and outputs a set of adjustment control parameters, forming a frequency reduction and torque increase parameter matrix containing specific values ​​for the frequency reduction magnitude and torque increase ratio. The parameter calculation unit packages the values ​​from the frequency reduction and torque increase parameter matrix to generate dynamic adjustment instructions in a standard communication protocol format. The data frame of the dynamic adjustment instruction precisely contains the specific control code for the frequency reduction magnitude and torque increase ratio.

[0034] The drive motor is connected to the variable frequency drive (VFD) assembly via a power cable. After receiving the dynamic adjustment command at its communication port, the VFD assembly's internal microprocessor decodes and parses the command. The VFD assembly converts the frequency reduction magnitude contained in the dynamic adjustment command into a stator voltage frequency control signal, which is used to control the conduction cycle of the inverter bridge switching transistors. Simultaneously, the VFD assembly converts the torque increase ratio contained in the dynamic adjustment command into a stator current amplitude control signal, which is used to control the output current limiting.

[0035] The stator windings of the drive motor receive regulated three-phase AC power. Strictly following the stator voltage frequency control signal, the rotor speed is synchronously reduced, and the stator magnetic flux is increased according to the stator current amplitude control signal, thereby significantly increasing the motor's output torque. The drive motor utilizes this greatly increased output torque to forcefully overcome the high-load viscous friction generated by the plastic sludge.

[0036] The control system is equipped with a state recovery module, which monitors the resistance decline trend. After outputting a high-load state indicator, the numerical comparison unit continues to monitor the resistance fluctuation difference at a fixed time step. As the sludge moisture content decreases and passes the plastic stage, the sludge friction gradually decreases. When the numerical comparison unit determines that the resistance fluctuation difference is less than or equal to zero, and the internal timer of the control system determines that the state of resistance fluctuation difference being less than or equal to zero continues for a set time period of 3 seconds, interference factors caused by transient force fluctuations are eliminated.

[0037] After eliminating interference factors, the numerical comparison unit sends a normal load indicator to the state recovery module. Upon receiving the normal load indicator, the state recovery module determines that the sludge turning resistance has returned to a safe range, immediately generates an operation recovery command, and sends the operation recovery command to the variable frequency drive component. The variable frequency drive component resets its control register according to the operation recovery command and sends the reference frequency control signal and reference current control signal initially set by the equipment to the drive motor. Finally, the speed and torque of the drive motor smoothly transition according to the set slope, restoring to the set reference operating state.

[0038] The drying chamber is equipped with multiple layers of heating discs fixed horizontally inside. These heating discs are used for indirect heating by introducing heat transfer oil. The drive motor rotates the central spindle, and the rake arm, together with the central spindle, maintains a horizontal position and rotates at a uniform speed parallel to the upper surface of the heating discs.

[0039] The rake blades are fixedly installed on the bottom side of the rake arm, always positioned above the heating disc in absolute spatial position. A set vertical gap of 5 to 8 mm is maintained between the bottom surface of the rake blades and the upper surface of the heating disc to prevent mechanical contact between the rake blades and easily adhered sludge materials when agitating them, and to avoid wear and damage to the surface of the heating disc caused by mutual scraping of metal parts.

[0040] Secondly, please refer to Figure 1 The present invention provides a control method for a sludge drying rake tooth device, applied to the sludge drying rake tooth device as described above, comprising: Step 1: The data receiving module receives the raw electrical signals transmitted by the torque detection element and the strain detection element, converts the raw electrical signals into a digital electrical signal sequence, and separates the deformation characteristic data and real-time torque data from the digital electrical signal sequence; Step 2: The resistance assessment module acquires the deformation characteristic data and the real-time torque data, uses the deformation characteristic data to calculate the instantaneous mechanical resistance value, and then constructs a resistance assessment data model that includes the instantaneous mechanical resistance value and the real-time torque data. Step 3: The instruction generation module obtains the instantaneous mechanical resistance value output by the resistance assessment data model, compares the instantaneous mechanical resistance value with the preset safety resistance threshold, and when it is determined that the instantaneous mechanical resistance value is greater than the safety resistance threshold, the instruction generation module calculates the load compensation characteristics and generates a dynamic adjustment instruction, and sends the dynamic adjustment instruction to the drive motor to drive the drive motor to increase the motor output torque.

[0041] In this embodiment of the invention, under the operating conditions of a vertical disc sludge drying and granulation equipment, municipal or industrial sludge to be processed enters the drying chamber from the top and is continuously agitated by rake blades driven by the rotation of the central main shaft. When the sludge moisture evaporates due to heat and the overall moisture content drops to the range of 40% to 60%, the sludge transforms from a conventional slurry state to a highly viscous, adhesive-plastic state. The probability of sludge in the plastic stage adhering to the surface of the dryer wall and forming scale increases significantly, resulting in a significant increase in the viscous resistance experienced by the rake blades when agitating the adhesive-plastic sludge. If the drive motor operates at a set constant rated speed, the drive motor faces the physical risk of overload and triggering overload protection shutdown.

[0042] Based on the resistance change characteristics, the control system calls the resistance assessment data model to process the viscous resistance data during the plastic stage. The input to the resistance assessment data model receives real-time torque data and deformation characteristic data from two independent sensor channels. The real-time torque data characterizes the overall torsional load state of the drive motor spindle, while the deformation characteristic data characterizes the compressive deformation displacement of the front rake blades when they contact the viscous sludge. The resistance assessment module includes a model building unit. This unit assigns a corresponding time identifier to each set of synchronously acquired real-time torque data and instantaneous mechanical resistance values, and aligns the two sets of discrete time-series data along the time dimension based on the time identifier, thereby constructing a correlation matrix mapping the dynamic force changes. The model building unit uses the assembled correlation matrix as the resistance assessment data model and outputs the instantaneous mechanical resistance value required for the rake blade tip to overcome the sludge viscosity to the control system's command generation module in real time.

[0043] The instruction generation module continuously acquires the instantaneous mechanical resistance value output by the resistance assessment data model. Under the set equipment operating conditions, the safe resistance threshold is set at 800 Newtons. When the instantaneous mechanical resistance value increases to 1200 Newtons and the instruction generation module determines that the instantaneous mechanical resistance value exceeds the safe resistance threshold, the instruction generation module initiates the overload response logic. The instruction generation module calculates the load compensation characteristics required to overcome the over-limit resistance. These load compensation characteristics are specifically manifested as the frequency reduction adjustment parameters and current increase compensation parameters applied to the frequency converter system.

[0044] Following the established data processing path, the instruction generation module inputs the calculated load compensation characteristics into the algorithm module and outputs a frequency reduction and torque increase parameter matrix, which includes parameters for frequency reduction magnitude and torque increase ratio. The frequency reduction magnitude parameter indicates that the operating frequency of the drive motor is reduced from the rated 50 Hz to 35 Hz, while the torque increase ratio parameter indicates that the upper limit of the output current of the frequency converter system is adjusted from 100% to 150% of the rated value. The instruction generation module generates dynamic adjustment instructions with a standard communication protocol format based on the frequency reduction and torque increase parameter matrix.

[0045] Upon entering the hardware execution level, the communication port of the frequency converter drive component receives dynamic adjustment commands. The frequency converter drive component converts the frequency reduction magnitude parameter contained in the dynamic adjustment commands into a stator voltage frequency control signal that reduces the conduction frequency of the inverter bridge switching transistors, and converts the torque increase ratio parameter into a stator current amplitude control signal that increases the inverter output current limiting threshold. The stator windings of the drive motor receive both the stator voltage frequency control signal and the stator current amplitude control signal, causing the motor rotor speed to decrease and the motor output torque to increase proportionally. The drive motor operates in a low-speed, high-torque heavy-load mode, cutting and crushing sludge clumps in the adhesive-plastic stage, maintaining the continuous rotation of the rake arm, and effectively preventing mechanical overload shutdowns of the drying equipment due to excessive local viscous resistance.

[0046] As the indirect drying process progresses, the moisture content of the turned sludge decreases to below 40%, and the sludge material breaks down and transforms into dried particles of 3 to 5 millimeters, eliminating its surface adhesive properties. After being transformed into a granular form, the mechanical resistance experienced by the rake blades is significantly reduced, and the state recovery module continuously monitors the system's operating status data. When the numerical comparison unit determines that the instantaneous mechanical resistance value has decreased to 600 Newtons and the resistance fluctuation difference becomes negative, the system initiates the recovery timing logic. After the resistance fluctuation difference is maintained at a value less than or equal to zero for a set time period of 3 seconds, the state recovery module sends a running recovery command to the variable frequency drive component. The variable frequency drive component outputs a 50 Hz reference frequency control signal and a 100% rated current reference current control signal according to the running recovery command. After receiving the signals, the drive motor smoothly restores the rotor speed and output torque to the reference operating state, completing the adaptive control process for the sludge plasticization stage.

Claims

1. A sludge drying rake device, comprising a mechanical body and a control system, characterized in that, The mechanical body includes a drying chamber, a central main shaft, a rake arm, a spring rake tooth assembly, and a drive motor. The central main shaft is arranged vertically inside the drying chamber. The rake arm, which is horizontally extended, is fixedly connected to the outer wall of the central main shaft. The spring rake tooth assembly is installed at the end of the rake arm away from the central main shaft. The spring rake tooth assembly includes an elastic buffer and a rake blade. The two ends of the elastic buffer are fixedly connected to the rake arm and the rake blade, respectively. The central main shaft is connected to the drive motor for transmission. A torque detection element is installed at the power output end of the drive motor, and a strain detection element is fitted onto the surface of the elastic buffer; the mechanical body establishes a communication connection with the control system; the control system includes a data receiving module, a resistance evaluation module, and an instruction generation module; The data receiving module receives the raw electrical signals transmitted by the torque detection element and the strain detection element, converts the raw electrical signals into a digital electrical signal sequence, and separates the deformation characteristic data and real-time torque data from the digital electrical signal sequence. The resistance assessment module acquires the deformation characteristic data and the real-time torque data, uses the deformation characteristic data to calculate the instantaneous mechanical resistance value, and then constructs a resistance assessment data model including the instantaneous mechanical resistance value and the real-time torque data. The instruction generation module obtains the instantaneous mechanical resistance value output by the resistance assessment data model, compares the instantaneous mechanical resistance value with a preset safety resistance threshold, and when it is determined that the instantaneous mechanical resistance value is greater than the safety resistance threshold, the instruction generation module calculates the load compensation characteristics and generates a dynamic adjustment instruction, and sends the dynamic adjustment instruction to the drive motor to drive the drive motor to increase the motor output torque.

2. The sludge drying rake device according to claim 1, characterized in that, The data receiving module includes an analog-to-digital conversion unit and a high-frequency filtering unit; The analog-to-digital conversion unit receives the original electrical signal and converts the original electrical signal into the digital electrical signal sequence; The high-frequency filtering unit filters the digital electrical signal sequence according to a preset low-pass filter cutoff frequency, separates the deformation characteristic data and the real-time torque data located below the low-pass filter cutoff frequency, and sends the deformation characteristic data and the real-time torque data to the resistance evaluation module.

3. The sludge drying rake device according to claim 2, characterized in that, The elastic buffer adopts a helical compression spring structure, and the strain detection element is attached along the axial force direction of the helical compression spring structure. The resistance assessment module acquires the deformation displacement values ​​included in the deformation characteristic data, calls the preset spring stiffness coefficient to multiply the deformation displacement values, and calculates the instantaneous mechanical resistance value.

4. The sludge drying rake device according to claim 3, characterized in that, The resistance assessment module includes a data alignment unit and a model building unit; The data alignment unit acquires the real-time torque data and assigns a consistent time identifier to the real-time torque data and the instantaneous mechanical resistance value; The model building unit establishes a mapping correlation matrix between the instantaneous mechanical resistance value and the real-time torque data based on the time identifier, and outputs the mapping correlation matrix as the resistance evaluation data model.

5. The sludge drying rake device according to claim 4, characterized in that, The instruction generation module includes a numerical comparison unit and a parameter calculation unit; The numerical comparison unit extracts the instantaneous mechanical resistance value output by the resistance assessment data model according to the set time step, and subtracts the safety resistance threshold from the instantaneous mechanical resistance value to output the resistance fluctuation difference. When the resistance fluctuation difference is determined to be greater than zero, the numerical comparison unit sends the high load status identifier and the resistance fluctuation difference to the parameter calculation unit.

6. The sludge drying rake tooth device according to claim 5, characterized in that, The parameter calculation unit receives the high load status indicator and the resistance fluctuation difference, and starts the proportional-integral-derivative control algorithm. The parameter calculation unit inputs the resistance fluctuation difference into the proportional integral derivative control algorithm for calculation, and outputs a frequency reduction and torque increase parameter matrix including the frequency reduction magnitude and torque increase ratio. The parameter calculation unit generates the dynamic adjustment command according to the frequency reduction and torque increase parameter matrix. The dynamic adjustment command includes the frequency reduction magnitude and the torque increase ratio.

7. The sludge drying rake device according to claim 6, characterized in that, The drive motor is connected to a frequency converter drive assembly; The variable frequency drive component receives the dynamic adjustment command, converts the frequency reduction magnitude included in the dynamic adjustment command into a stator voltage frequency control signal, and converts the torque increase ratio included in the dynamic adjustment command into a stator current amplitude control signal. The drive motor reduces its speed according to the stator voltage frequency control signal and increases its output torque according to the stator current amplitude control signal.

8. The sludge drying rake tooth device according to claim 7, characterized in that, The control system further includes a state recovery module; The numerical comparison unit continuously monitors the resistance fluctuation difference. When the resistance fluctuation difference is less than or equal to zero and remains for a set time period, it sends a normal load identifier to the state recovery module. The status recovery module receives the normal load identifier, generates an operation recovery command, and sends the operation recovery command to the frequency converter drive component; The variable frequency drive component sends a reference frequency control signal and a reference current control signal to the drive motor according to the operation recovery command, thereby driving the drive motor to return to the set reference operating state.

9. The sludge drying rake tooth device according to claim 8, characterized in that, A heating disc is fixed horizontally inside the drying chamber. The rake arm, together with the central main shaft, maintains a horizontal state and rotates parallel to the heating disk; The rake blade is located above the heating disk, and the bottom end face of the rake blade maintains a set vertical gap with the upper surface of the heating disk.

10. A control method for a sludge drying rake tooth device, applied to the sludge drying rake tooth device as described in any one of claims 1 to 9, characterized in that, include: Step 1: The data receiving module receives the raw electrical signals transmitted by the torque detection element and the strain detection element, converts the raw electrical signals into a digital electrical signal sequence, and separates the deformation characteristic data and real-time torque data from the digital electrical signal sequence; Step 2: The resistance assessment module acquires the deformation characteristic data and the real-time torque data, uses the deformation characteristic data to calculate the instantaneous mechanical resistance value, and then constructs a resistance assessment data model that includes the instantaneous mechanical resistance value and the real-time torque data. Step 3: The instruction generation module obtains the instantaneous mechanical resistance value output by the resistance assessment data model, compares the instantaneous mechanical resistance value with the preset safety resistance threshold, and when it is determined that the instantaneous mechanical resistance value is greater than the safety resistance threshold, the instruction generation module calculates the load compensation characteristics and generates a dynamic adjustment instruction, and sends the dynamic adjustment instruction to the drive motor to drive the drive motor to increase the motor output torque.

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