A coal mine auxiliary transportation transfer robot PMSM cooperative braking control method

Abstract

The present application relates to a kind of coal mine auxiliary transport transfer robot PMSM collaborative braking control method, belong to coal mine auxiliary transport system application technical field, including the following steps: obtaining the attitude information and load information of each drive unit;According to the attitude information, determine the track working condition where each drive unit is located;Based on the track working condition, select the speed control strategy;According to the load information and the speed control strategy, the permanent magnet synchronous motor of each drive unit is implemented collaborative braking control;Monitoring load platform vibration state, assesses running stability, through grouping speed control strategy and error convergence mechanism, ensure the speed synchronization of motor in each drive group, reduce the problem of poor collaboration caused by uneven stress of track slope transition section, improve the stability of whole machine operation.

Description

Technical Field

[0001] This invention relates to a collaborative braking control method for a PMSM (Potentially Integrated Transportation System) auxiliary transport robot in coal mines, belonging to the field of application technology for coal mine auxiliary transport systems. Background Technology

[0002] Coal mine auxiliary transport and transfer robots are used for underground material transport and personnel and equipment transport. The underground environment is complex and the transport routes are diverse. To ensure the safety of personnel and goods during the transport process, the stability of the braking of the track gradient transition section when going downhill is particularly important.

[0003] Traditional coal mine auxiliary transport and transfer robots primarily rely on hydraulic motor-driven coordinated braking for braking. However, hydraulic motors have shortcomings in synchronization range and mechanical structure, leading to problems such as large impacts and slow response during braking. They are gradually being replaced by electric braking methods. Currently, however, the braking control of coal mine auxiliary transport and transfer robots based on motor drives mostly employs traditional control strategies, failing to fully consider the inherent characteristics of permanent magnet synchronous motors (PMSMs) and the complex and special working conditions in underground coal mines. For complex conditions such as heavy-load downhill slopes, multi-motor coordinated braking control suffers from poor coordination and inaccurate control, resulting in unstable braking and long braking distances, affecting the braking performance and operational stability of the coal mine auxiliary transport and transfer robot.

[0004] Therefore, there is an urgent need for a collaborative braking control method for PMSM (Potentially Targeted Motor Module) auxiliary transportation and transfer robots in coal mines. Summary of the Invention

[0005] The purpose of this invention is to address the issues of unstable braking and severe vibration of the load platform in coal mine auxiliary transport and transfer robots during the braking process at the track gradient transition section on downhill slopes. Research on the vibration problem of the load platform in coal mine auxiliary transport and transfer robots has revealed that it is mainly due to insufficient coordination and inaccurate control of the multi-motor cooperative braking system, leading to unstable braking and excessive vibration amplitude of the load platform. Therefore, this invention proposes a PMSM (Permanent Magnet Synchronous Motor) cooperative braking control method for coal mine auxiliary transport and transfer robots.

[0006] This invention proposes a PMSM (Potentially Targeted Motor Module) cooperative braking control method for coal mine auxiliary transport and transfer robots, comprising the following steps:

[0007] Acquire the attitude and load information of each drive unit;

[0008] Based on the attitude information, the track conditions of each drive unit are determined.

[0009] Based on the aforementioned track conditions, a speed control strategy is selected;

[0010] Based on the load information and the speed control strategy, coordinated braking control is implemented on the permanent magnet synchronous motors of each drive unit;

[0011] Monitor the vibration status of the load platform and assess its operational stability.

[0012] Preferably, the step of obtaining the attitude information and load information of each driving unit includes:

[0013] Accelerometers installed at the ends of key drive shafts and chassis support points of the drive unit are used to monitor the vibration attitude of the drive unit in real time.

[0014] The tilt angle of the drive unit is measured by an tilt sensor mounted on the main frame of the drive unit.

[0015] The position of the drive unit is obtained by a position encoder integrated into the output shaft of the drive motor;

[0016] The real-time output torque is measured by a torque sensor installed at the connection between the drive motor and the reducer.

[0017] Preferably, the step of determining the track conditions of each drive unit includes:

[0018] Obtain the initial speed of each motor and the angle between each drive unit and the horizontal plane;

[0019] When the angle between the drive unit and the horizontal plane is greater than a preset threshold, it is determined that the drive unit is in inclined rail working condition;

[0020] When the angle between the drive unit and the horizontal plane is less than or equal to a preset threshold, the drive unit is determined to be in a straight rail working condition.

[0021] Preferably, the step of selecting a speed control strategy based on track conditions includes:

[0022] Divide multiple drive units into several drive groups;

[0023] Obtain the horizontal angle between the first drive unit in the first drive group and the last drive unit in the last drive group;

[0024] When the angle between the first drive unit and the horizontal plane is greater than the angle between the last drive unit and the horizontal plane, the first drive group is controlled first, and the subsequent drive group uses the output speed of the previous drive group as the desired input speed.

[0025] When the angle between the first drive unit and the horizontal plane is less than the angle between the last drive unit and the horizontal plane, the last drive group is controlled first, and the output speed of the preceding drive group is used as the desired input speed.

[0026] Preferably, the step of dividing the multiple drive units into several drive groups includes:

[0027] Group three adjacent drive units together;

[0028] In each group, select the drive unit in the middle position as the main drive unit of that group;

[0029] Set the remaining drive units as slave drive units.

[0030] Preferably, the step of implementing coordinated braking control of the permanent magnet synchronous motors of each drive unit includes:

[0031] Coordinated braking is achieved by combining master-slave control with deviation coupling control.

[0032] The position compensation signal is generated by processing the difference between the desired speed and the actual speed of the main motor through the position compensator.

[0033] Based on the actual speed change of the motor, a speed deviation compensation signal is generated through a coupling link;

[0034] The position compensation signal and the speed deviation compensation signal are fed back to the speed controller of the main motor to achieve load compensation.

[0035] Preferably, the generation of the position compensation signal includes:

[0036] For the first drive group, calculate the first position compensation signal:

[0037] Δθ1=kp1(ω0-ω2)+ki1∫(ω0-ω2)dt;

[0038] For the second drive group, calculate the second position compensation signal:

[0039] Δθ2=kp2(ω2-ω0')+ki2∫(ω2-ω0')dt;

[0040] Where ω0 is the desired speed, ω2 is the actual speed of the main motor of the first drive group, ω0' is the actual speed of the main motor of the second drive group, and kp1, ki1, kp2, and ki2 are control parameters.

[0041] Preferably, the generation of the speed deviation compensation signal includes:

[0042] Calculate the proportional error term among the motors in the drive group;

[0043] Based on the aforementioned proportional error term, calculate the speed deviation compensation value;

[0044] For the first drive group, the speed deviation compensation value Δω0=k 12(k1ω1-k2ω2)+k 23 (k2ω2-k3ω3);

[0045] For the second drive group, the speed deviation compensation value Δω1=k 45 (k4ω4-k5ω5)+k 56 (k5ω5-k6ω6);

[0046] Where ω1 to ω6 are the speeds of each motor, k1 to k6 are the proportional factors, and k 12 k 23 k 45 k 56 This is the dynamic gain adjustment coefficient.

[0047] Preferably, the steps for monitoring the vibration state of the load platform and assessing its operational stability include:

[0048] Collect data from the accelerometer and tilt sensor;

[0049] The data is then filtered, amplified, and standardized.

[0050] Real-time calibration is performed using embedded algorithms;

[0051] The attitude stability of the drive unit is evaluated by combining acceleration and tilt angle data;

[0052] The load safety threshold is dynamically adjusted based on torque data.

[0053] Preferably, after implementing coordinated braking control of the permanent magnet synchronous motors of each drive unit, the method further includes:

[0054] Evaluate the speed synchronization error between the motors;

[0055] Determine whether each proportional error term has converged to the preset range;

[0056] When the proportional error term fails to converge to the preset range, adjust the dynamic gain adjustment coefficient.

[0057] The vibration amplitude of the load platform during braking is continuously monitored. When the vibration amplitude exceeds the safety threshold, the control parameters are adjusted to reduce the vibration amplitude.

[0058] The beneficial effects of this invention are as follows:

[0059] 1. Enhance multi-motor coordination: By using group speed regulation strategies (such as P2 and P5 as main motors) and error convergence mechanisms (such as proportional factors and variable gain adjustment factors), the speed of motors in each drive group is synchronized, reducing the problem of poor coordination caused by uneven force in the transition section of track slope, and improving the overall stability of the machine operation.

[0060] 2. Adaptable to complex underground working conditions: The speed regulation strategy is dynamically switched according to the track conditions (straight or inclined) of the drive unit. Combined with real-time load monitoring and compensation, it can flexibly cope with special working conditions such as varying slopes and heavy loads in coal mines, ensuring the reliable operation of the system in harsh environments.

[0061] 3. Shorten braking distance: By adopting a master-slave control and deviation coupling control strategy, multi-motor coordination is achieved through speed deviation compensation and position compensation signals, which effectively suppresses the impact of load disturbance on the whole machine, improves braking response speed and control accuracy, and thus shortens the braking distance under complex working conditions such as heavy load downhill. Attached Figure Description

[0062] Figure 1 Block diagram of the status monitoring system for the speed control unit of the auxiliary transportation and transshipment robot in a coal mine;

[0063] Figure 2 Flowchart for status monitoring of speed control system of auxiliary transportation and transshipment robot in coal mine;

[0064] Figure 3 A schematic diagram showing the layout of the drive units of a coal mine auxiliary transportation and transfer robot.

[0065] Figure 4 Flowchart of the method for selecting a speed control module for a coal mine auxiliary transportation and transshipment robot;

[0066] Figure 5 Block diagram of multi-motor collaborative control strategy for auxiliary transportation and transshipment robots in coal mines;

[0067] Figure 6 This is a block diagram of the motor speed deviation compensation method. Detailed Implementation

[0068] Please refer to the attached document. Figure 1-6 The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0069] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0070] This invention provides a PMSM (Potentially Integrated Motor) cooperative braking control method for coal mine auxiliary transport and transfer robots, comprising the following steps:

[0071] S1: Drive unit attitude detection, obtain the initial speed (ωi) of each motor and the attitude information of each drive unit (angle between the drive unit and the horizontal plane (ψi)), and determine whether the track condition of each drive unit is a straight rail or an inclined rail.

[0072] S2: Drive unit load monitoring, which monitors the load torque of each drive unit in real time.

[0073] S3: Speed ​​control selection module, selects speed control strategy according to the track conditions of each drive unit.

[0074] S4: Speed ​​control module, which performs load compensation for each drive unit PMSM based on the real-time feedback load disturbance signal of each drive unit.

[0075] S5: Load platform vibration monitoring module, used to assess the operational stability of coal mine auxiliary transportation and transfer robots.

[0076] To achieve the above steps, the present invention first provides a status monitoring system for the speed regulation system of the drive unit of a coal mine auxiliary transportation and transfer robot, such as... Figure 1 As shown, it includes:

[0077] The sensor system includes a drive unit attitude sensor and a load monitoring sensor. The drive unit attitude sensor includes an accelerometer, a tilt sensor, and a position encoder. The accelerometer is mounted on the end of a key drive shaft and at a chassis support point to monitor the drive unit's vibration attitude in real time. The tilt sensor is mounted on the main frame of the drive unit to measure its tilt angle. The position encoder is integrated into the output shaft of the drive motor to accurately feedback the drive unit's position. The load monitoring sensor, also known as a torque sensor, is mounted at the connection between the drive motor and the reducer to measure the real-time output torque.

[0078] The whole machine operation status data acquisition and processing module includes: a signal conditioning module, which is used to filter, amplify and standardize the analog signals output by the sensors; a multi-channel acquisition module, which supports the synchronous acquisition of speed, position, acceleration, torque and controller status data, and performs real-time calibration through embedded algorithms; and a data communication module, which uses the industrial Ethernet protocol to transmit the processed data to the status monitoring database.

[0079] The overall machine operation status assessment system includes the following functions: assessing the attitude stability of the drive unit by combining acceleration and tilt angle data; and dynamically adjusting the load safety threshold based on torque and oil pressure data.

[0080] Figure 2 The process of monitoring the status of the speed regulation system of the coal mine auxiliary transportation and transfer robot is demonstrated, including five main steps from S1 to S5, forming a complete monitoring and evaluation closed loop.

[0081] Example 1: Method for Attitude Detection and Determination of Driving Unit

[0082] This embodiment details how to implement attitude detection of the drive unit and determine the track conditions.

[0083] First, the vibration attitude of the drive unit is monitored using accelerometers. Preferably, a triaxial accelerometer with a sensitivity of ±2g and a sampling frequency of 100Hz is used, and it is installed at the ends of key drive shafts and chassis support points of each drive unit. These sensors acquire acceleration data in the vertical, horizontal, and lateral directions, thus providing a comprehensive understanding of the drive unit's vibration state.

[0084] Secondly, the angle ψi between the drive unit and the horizontal plane is measured using an inclination sensor. This sensor is mounted on the main frame of each drive unit, with a measurement accuracy of ±0.1° and a measurement range of ±45°. When ψi is greater than a preset threshold (e.g., 5°), the drive unit is determined to be in inclined rail operation; when ψi is less than or equal to the threshold, it is determined to be in straight rail operation.

[0085] In addition, the initial speed ωi and precise position information of each motor are obtained by a position encoder integrated into the output shaft of the drive motor. This encoder has a resolution of 1024 lines / revolution and provides high-precision position and speed feedback.

[0086] Furthermore, the specific method for determining the operating condition in this embodiment is as follows:

[0087] When the included angle ψ1 of the first drive unit (e.g., P1) is greater than the included angle ψ6 of the sixth drive unit (e.g., P6), it indicates that the machine is entering the downhill section and the front drive unit has entered the inclined track; when ψ1 equals ψ6, it indicates that the machine is completely on the inclined track; when ψ1 is less than ψ6, it indicates that the front end of the machine has entered the straight track section. These determinations are crucial for the subsequent selection of speed control strategies.

[0088] Example 2: Drive Unit Load Monitoring Method

[0089] This embodiment details how to implement drive unit load monitoring.

[0090] This invention employs torque sensors for load monitoring, which are installed at the connection points between each drive motor and the reducer. The torque sensors have a range of 0-500 N·m, an accuracy of ±0.5% of full scale, and a sampling frequency of 200 Hz. Through these sensors, the system can acquire real-time load torque data for each drive unit.

[0091] In practical applications, the load on each drive unit varies significantly under different operating conditions. Especially in the transition section of the track gradient, the uneven load distribution is caused by the different times when each drive unit enters the inclined track. Typically, the drive units that enter the inclined track first (such as P1 and P3) bear a larger load impact, and their torque value may suddenly increase to 1.5 to 2 times the steady-state value. At this time, accurate load monitoring is crucial for subsequent load compensation.

[0092] In addition, the system filters the torque data, using a low-pass filter to remove high-frequency noise, with the filter's cutoff frequency set to 50Hz. The processed torque data is then used to calculate load disturbance signals, providing fundamental data support for speed control.

[0093] Example 3: Speed ​​Control Selection Method

[0094] In this embodiment, the implementation method of the speed control selection module is described in detail, such as... Figure 4 As shown.

[0095] First, the multiple drive units of the coal mine auxiliary transportation and transfer robot are divided into several drive groups. Considering practical application requirements, a preferred grouping method is to group three adjacent drive units together, for example, P1, P2, and P3 form the first drive group, P4, P5, and P6 form the second drive group, and so on. Within each drive group, the drive unit in the middle position (such as P2 and P5) is selected as the master drive unit of the group, and the remaining drive units are slave drive units.

[0096] like Figure 3 As shown, considering the position of the coal mine auxiliary transportation and transfer robot during the downhill process, P2 is located in the middle of the transition section, which is conducive to the smooth transition and coordinated control of the system. The signal transmission distance is relatively short, which can reduce control delay. From the perspective of system stability, P2 is located in the middle of the whole machine, and compared with P1 and P3 in the transition section of the track slope, it is less affected by the load impact, which can better balance the force, reduce vibration and jamming in the transition section, and ensure safe and stable operation under complex working conditions. The reason for choosing P5 as the main motor of drive group 2 is the same as above.

[0097] Next, the control sequence is determined by comparing the horizontal angle between the first drive unit (P1) in the first drive group and the last drive unit (P6) in the last drive group.

[0098] When the machine is descending a slope, when P1 is initially on the inclined rail, the angle ψ1 between its drive unit and the horizontal plane is greater than the angle ψ6 between the drive unit of P6 and the horizontal plane. As the machine moves, when all drive units are on the inclined rail, ψ1 equals ψ6. In both of these conditions, the second drive group uses the output speed of the first drive group as the desired input speed (its specific control strategy is as follows). Figure 5(As shown). When the drive unit to which P1 belongs is on the straight track, ψ1 is less than ψ6, and the first drive group uses the output speed of the second drive group as the desired input speed.

[0099] This condition-based dynamic speed control selection can effectively cope with the complex and ever-changing track conditions in coal mines, ensuring the stability and safety of the entire machine's operation.

[0100] Example 4: Speed ​​Control Method

[0101] In this embodiment, the implementation method of the speed control module is described in detail, such as... Figure 5 As shown.

[0102] The speed control of this invention employs a control strategy that combines master-slave control with deviation coupling. Figure 3 The motor layout diagram shows that P2 and P5 are selected as the main motors for each drive group.

[0103] When the speed of the main motor P2 changes for some reason, the actual speed ω2 fed back by the speed and position detection module will deviate from the desired speed ω0, and the speed controller will make corresponding adjustments. At the same time, the position compensators of the slave motors P1 and P3 will process the difference between the desired speed ω0 and the actual speed ω2 of the main motor P2 to generate a position compensation signal.

[0104] For the first drive group, the position compensation signal is calculated as follows:

[0105] Δθ1=k p1 (ω0-ω2)+k i1 ∫(ω0-ω2)dt

[0106] Where, k p1 is a proportionality coefficient, ranging from 0.5 to 2.0, with a preferred value of 1.2; k i 1 represents the integral coefficient, ranging from 0.05 to 0.5, with a preferred value of 0.25. These parameters can be fine-tuned according to actual operating conditions to obtain the best control effect. For the second drive group, the position compensation signal is calculated as follows:

[0107] Δθ2=k p2 (ω2-ω0′)+k i2 ∫(ω2-ω0′)dt

[0108] Where ω′0 is the actual speed of the main motor P5 of the second drive group, k p2 and k i2 The parameter settings are similar to those of the first drive group.

[0109] Considering that P1 and P3 experience significant load impacts during the track gradient transition section, and given the different torques of motors P1 and P3 due to load forces, their different load disturbances T1 and T3 are taken into account. The coupling element generates Δω0 based on the actual speed changes of motors P1 and P3, which is then input to the load compensation module to generate a speed deviation compensation signal. This signal is fed back to the speed controller to achieve more precise and stable control of the main motor P2's speed, reducing the impact of load disturbances on the entire machine.

[0110] Drive group two uses the output speed ω2 of drive group one as the desired input speed and achieves coordinated braking through a similar control process.

[0111] Example 5: Motor speed deviation compensation method

[0112] In this embodiment, the motor speed deviation compensation method is described in detail, such as... Figure 6 As shown.

[0113] This method first calculates the proportional error term between the motors within the drive group:

[0114] For the first drive group:

[0115] error 12 (t)=k1ω1-k2ω2

[0116] error 23 (t)=k2ω2-k3ω3

[0117] For the second drive group:

[0118] error 45 (t)=k4ω4-k5ω5

[0119] error 56 (t)=k5ω5-k6ω6

[0120] Among them, the proportional error term error 12 (t) represents the result of weighting the speed difference between the permanent magnet synchronous motors PMSM-1 and PMSM-2 using scaling factors k1 and k2, error 23 (t) corresponds to the error between PMSM-2 and PMSM-3 calculated using proportional coefficients k2 and k3. The values ​​of k1 to k6 range from 0.8 to 1.2, with the preferred values ​​being fine-tuned according to the characteristics of each motor, typically close to 1.0.

[0121] To achieve synchronous operation of multiple motors, it is necessary to ensure that the proportional error between the main motor PMSM-2 and the adjacent motors (PMSM-1 and PMSM-3) gradually approaches zero over time, i.e., reaching a stable convergence state.

[0122] limt→∞ error 12 (t)=lim t→∞ (k1ω1-k2ω2)=0

[0123] lim t→∞ error 23 (t)=lim t→∞ (k2ω2-k3ω3)=0

[0124] lim t→∞ error 45 (t)=lim t→∞ (k4ω4-k5ω5)=0

[0125] lim t→∞ error 56 (t)=lim t→∞ (k5ω5-k6ω6)=0

[0126] Based on the above proportional error term, calculate the speed deviation compensation value:

[0127] Δω0=k 12 (k1ω1-k2ω2)+k 23 (k2ω2-k3ω3)

[0128] Δω1=k 45 (k4ω4-k5ω5)+k 56 (k5ω5-k6ω6)

[0129] Where, k 12 This is the dynamic gain adjustment coefficient between PMSM-2 and PMSM-1, with a value ranging from 0.2 to 1.0, and a preferred value of 0.5; k 23 Used to adjust the gain variation between PMSM-2 and PMSM-3, with a value range similar to k. 12 Same; k 45 and k 56 These correspond to the adaptive gain adjustment parameters between PMSM-5 and PMSM-4, and PMSM-5 and PMSM-6, respectively, with values ​​ranging from 0.2 to 1.0. These coefficients can be determined based on the synchronization performance of the coordinated control of each motor under actual operating conditions.

[0130] In practical applications, when a significant deviation in the speed of a motor is detected (e.g., exceeding 5%), the system automatically adjusts the corresponding dynamic gain coefficient to accelerate error convergence. For example, if the error... 12 If (t) suddenly increases, the system will appropriately increase k. 12 The value (e.g., increasing from 0.5 to 0.8) is increased to enhance the compensation for this error.

[0131] Example 6: Vibration Monitoring Method for Load Platform

[0132] This embodiment details a method for monitoring the vibration of a load platform.

[0133] This method first collects data using accelerometers and tilt sensors. The data collected by the accelerometers mainly reflects the vibration amplitude and frequency of the load platform, while the data from the tilt sensors reflects changes in the platform's tilt state.

[0134] These raw data are processed by the signal conditioning module, including:

[0135] (1) Filtering: Use a Butterworth low-pass filter to remove high-frequency noise, with the cutoff frequency set to 50Hz;

[0136] (2) Amplification: Amplify the weak signal appropriately. The amplification factor is dynamically adjusted according to the signal strength, generally 1-10 times.

[0137] (3) Standardization conversion: Convert the signals output by different sensors into a standard format for easier subsequent processing.

[0138] The processed data is synchronously acquired through a multi-channel acquisition module at a sampling frequency of 200Hz, which meets the requirements for real-time monitoring. The acquired data is calibrated in real time using an embedded algorithm to eliminate the effects of sensor drift and nonlinear errors.

[0139] In terms of driving unit attitude stability evaluation, the system combines acceleration and tilt angle data to calculate a comprehensive evaluation index:

[0140]

[0141] Where SI is the stability index, and A rms Let A be the root mean square value of acceleration. th The acceleration threshold (usually set to 0.5g) SI represents the tilt angle change rate, and α and β are weighting coefficients, taken as 0.6 and 0.4 respectively. When the SI value is less than 1, it indicates that the drive unit's attitude is stable; when the SI value is greater than 1, it indicates the presence of unstable factors, requiring adjustment of the control parameters.

[0142] In addition, the system dynamically adjusts the load safety threshold based on torque data. By analyzing historical operating data, a torque-load relationship model is established. When the measured torque exceeds 80% of the safety threshold, the system issues a warning; when it exceeds 95%, an emergency protection mechanism is triggered to prevent overload damage.

[0143] Example 7: Optimization Method for Cooperative Braking Control Parameters

[0144] In this embodiment, a method for optimizing the coordinated braking control parameters is described in detail.

[0145] In practical applications, to achieve the best effect in coordinated braking control, it is necessary to optimize the control parameters. This invention employs the following steps for parameter optimization:

[0146] (1) Assess the speed synchronization error between motors: Calculate the synchronization error index (SEI) between motors in each drive group:

[0147]

[0148] Where, ω i Let ω be the actual speed of the i-th motor. ref Here, 'n' represents the reference speed (usually the main motor speed), and 'n' represents the number of motors. A smaller SEI value indicates better synchronization. Generally, an SEI value less than 3% is required.

[0149] (2) Determine whether each proportional error term has converged to the preset range: Check whether each proportional error term errorij(t) satisfies the condition: |error ij (t)|<ε,

[0150] Here, ε is the preset error tolerance, which is usually taken as 1% of the maximum speed. If this condition is not met, the relevant parameters need to be adjusted.

[0151] (3) Adjusting the dynamic gain adjustment coefficient: When the proportional error term fails to converge effectively, the system will automatically adjust the dynamic gain adjustment coefficient (such as k12, k23, etc.). The adjustment strategy is as follows:

[0152]

[0153] Wherein, γ is an adjustment coefficient, ranging from 0.1 to 0.5, with an optimal value of 0.25. This adaptive adjustment method can dynamically optimize the gain coefficient according to the magnitude of the error, thereby accelerating system convergence.

[0154] (4) Continuously monitor the vibration amplitude of the load platform during braking: Monitor the vibration in real time using an accelerometer and calculate the vibration intensity index VI.

[0155]

[0156] Where a(t) is the acceleration signal, and T is the sampling time window length (usually 1 second). When the VI value exceeds the safety threshold (e.g., 0.8g), the control parameters are adjusted to reduce the vibration amplitude.

[0157] By using the above parameter optimization methods, the system can adaptively adjust under different operating conditions, ensuring the stability and reliability of the coordinated braking control.

[0158] Example 8: Detailed Implementation of Working Condition-Based Group Speed ​​Control Strategy

[0159] In this embodiment, the implementation method of the working condition-based group speed regulation strategy is further described in detail.

[0160] As mentioned earlier, the drive units of the coal mine auxiliary transportation and transfer robot are divided into several groups (e.g., P1, P2, and P3 are the first group, and P4, P5, and P6 are the second group). The core of the group speed regulation strategy is to dynamically determine the control sequence and method based on the track conditions of each group.

[0161] The specific implementation steps are as follows:

[0162] (1) Real-time acquisition of tilt information of each drive unit: The tilt angle ψi between each drive unit and the horizontal plane is obtained by tilt sensor, and the sampling frequency is 50Hz to ensure the real-time performance of the data.

[0163] (2) Determine the track conditions of each drive unit: Set the inclined track determination threshold ψth to 5°. When ψi>ψth, the drive unit is determined to be on an inclined track; when ψi≤ψth, it is determined to be on a straight track.

[0164] (3) Determine the control priority of each drive group: Compare the tilt angles of the first unit P1 of the first drive group and the last unit P6 of the last drive group. When ψ1>ψ6, it indicates that the whole machine is moving from the straight rail to the inclined rail, and the front end is controlled first; when ψ1<ψ6, it indicates that the whole machine is returning from the inclined rail to the straight rail, and the rear end is controlled first; when ψ1=ψ6, it indicates that the whole machine is in the same working condition, and the interlocking control method is adopted.

[0165] (4) Implement a group control strategy: For the drive group with priority control, its main motor (e.g., P2) is controlled independently with the desired speed ω0 as the target; for the drive group without priority control, its main motor (e.g., P5) uses the actual output speed of the main motor of the priority group as the desired input speed. This series control method can achieve a smooth transition and reduce the impact of operating condition switching.

[0166] For example, during a downhill descent, when the front drive unit enters the inclined rail first, the front drive group initiates braking control, and the rear drive group targets the output speed of the front group, forming a "leading and following" relationship. In this way, the entire machine can maintain a coordinated and consistent motion state when different parts experience changes in operating conditions, greatly improving operational stability.

[0167] In practical applications, to further improve control accuracy, a "transition coefficient" β can be introduced to smooth the switching process between operating conditions.

[0168] ω target = (1-β)×ω prior +β×ω0,

[0169] Where, ω target For the target velocity of the non-priority group, ω prior ω0 is the output speed of the priority group, β is the original desired speed, and β is the transition coefficient, ranging from 0 to 1. When β = 0, it completely follows the priority group; when β = 1, it uses the original desired speed. In the initial stage of the operating condition switch, the value of β is small (e.g., 0.2). As the switch progresses, the value of β gradually increases (e.g., to 0.8) to achieve a smooth transition.

[0170] Example 9: Braking Control Strategies under Different Load Conditions

[0171] This embodiment details a method for adjusting braking control strategies under different load conditions.

[0172] In practical applications, coal mine auxiliary transportation and transfer robots experience significant load variations, ranging from empty to full load and even overload. These different load conditions place varying demands on braking control. This invention automatically adjusts control parameters based on load conditions to ensure braking stability under all circumstances.

[0173] (1) Load identification: The load torque of each drive unit is monitored in real time by torque sensors, and the average load rate LR is calculated.

[0174]

[0175] Among them, T i T represents the actual torque of the i-th drive unit. rated Where is the rated torque, and n is the number of drive units. Based on the LR value, the load conditions are divided into three cases: light load (LR<30%), medium load (30%≤LR<70%), and heavy load (LR≥70%).

[0176] (2) Braking control parameter adjustment: Adjust the parameters of the position compensation signal and speed deviation compensation signal according to different load conditions:

[0177] Braking control parameter adjustment: Adjust the parameters of the position compensation signal and speed deviation compensation signal for different load conditions.

[0178] For light load conditions: proportional coefficient k p1 k p2 Take the smaller value (e.g., 0.8 times the standard value);

[0179] Integral coefficient k i1 k i2 Smaller values ​​(e.g., 0.6 times the standard value);

[0180] Dynamic gain adjustment coefficient k 12 k 23 Take the smaller value (e.g., 0.7 times the standard value);

[0181] For medium-load conditions, standard parameter settings are used:

[0182] For heavy load conditions: proportional coefficient k p1 k p2 Take the larger value (e.g., 1.2 times the standard value);

[0183] Integral coefficient k i1 k i2 Larger values ​​(e.g., 1.5 times the standard value);

[0184] Dynamic gain adjustment coefficient k 12 k 23 Take the larger value (e.g., 1.3 times the standard value);

[0185] (3) Braking force distribution strategy: Under heavy load downhill conditions, a non-uniform braking force distribution strategy is adopted to improve braking effect. The front drive units (such as P1, P2, P3) undertake a greater braking task, while the rear drive units (such as P4, P5, P6) focus more on attitude stability control. The braking force distribution ratio is dynamically determined by the load distribution. Under normal circumstances, the braking force ratio of the front:rear is about 6:4.

[0186] (4) Anti-slip control: Under heavy load conditions, slippage is prone to occur during braking, affecting the braking effect. This invention determines whether slippage has occurred by monitoring the difference between the actual acceleration and the theoretical acceleration of each drive unit.

[0187] Δa=|a actual -a theoretical |,

[0188] When Δa exceeds the threshold (e.g., 0.3g), it is determined that slippage has occurred, and the system automatically reduces the braking force of the corresponding drive unit until the slippage phenomenon is eliminated.

[0189] Through the above strategy, the present invention can maintain good braking performance under various load conditions, especially under the most demanding condition of heavy-load downhill, it can still ensure safe and smooth braking.

[0190] Example 10: System Fault Detection and Fault-Tolerant Control

[0191] This embodiment details the system fault detection and fault-tolerant control method.

[0192] In actual operation, sensor failures, motor failures, or controller failures may occur. This invention provides a complete fault detection and fault-tolerant control mechanism to ensure that the system can still operate safely even if some components fail.

[0193] (1) Sensor fault detection: Real-time monitoring and effectiveness verification of the output signals of various sensors.

[0194] Signal range detection: Check whether the signal is within a reasonable range. For example, the output of the accelerometer should be within ±2g. If it exceeds this range, it is considered a possible fault.

[0195] Rate of change detection: Analyze whether the rate of change of the signal is reasonable. For example, the rotational speed should not change abruptly in a short period of time.

[0196] Consistency check: Compare the data consistency between similar sensors. For example, the readings of encoders at adjacent positions should have a reasonable correlation.

[0197] When a potential sensor malfunction is detected, the system will take different strategies depending on the importance of the malfunctioning sensor: for critical sensors (such as the main motor position encoder), safety braking will be triggered; for non-critical sensors, the system will switch to redundant sensors or use data estimation methods to compensate for the lost information.

[0198] (2) Motor fault detection: Monitor the motor's current, temperature, vibration and other parameters to determine whether the motor is working properly.

[0199] Overcurrent protection: When the motor current exceeds 1.5 times the rated value for more than 3 seconds, it is determined to be an overcurrent fault.

[0200] Over-temperature protection: When the motor temperature exceeds 85℃, it is determined to be an over-temperature fault.

[0201] Stall detection: When the input current is normal but the output speed is abnormally low, it is determined that the motor may be stalling.

[0202] When a motor failure is detected, the system will automatically isolate the faulty motor and reallocate the control tasks of the remaining motors to ensure that the whole machine can still maintain its basic functions.

[0203] (3) Fault-tolerant control strategy: In the event of partial component failure, the system adopts the following fault-tolerant control strategy:

[0204] Single motor failure: When a slave motor fails, the corresponding master motor increases its output torque (not exceeding 120% of the rated value), and other normal slave motors appropriately increase their output to jointly compensate for the failure of the master motor.

[0205] Main motor failure: When the main motor of a drive group fails, one of the normally functioning slave motors in the group is selected as the temporary main motor to take over the control responsibilities of the main motor.

[0206] Multi-motor failure: When multiple motors fail simultaneously, the system enters emergency braking mode, and all normally operating motors work together to apply maximum braking force to bring the entire machine to a safe stop as quickly as possible.

[0207] (4) Safety redundancy design: The system is equipped with a mechanical backup braking device. When the electrical braking system fails, the mechanical braking will be automatically activated to ensure the last safety guarantee.

[0208] Through the above-mentioned fault detection and fault-tolerant control measures, the present invention greatly improves the reliability and safety of the coal mine auxiliary transportation and transfer robot. Even in the event of partial component failure, it can still ensure the basic functions and safety of the system and avoid the risk of the whole machine being paralyzed due to local failure.

[0209] In summary, the PMSM collaborative braking control method for coal mine auxiliary transport and transfer robots provided by this invention effectively solves problems such as unstable braking and severe vibration of the load platform during downhill track gradient transitions in coal mine auxiliary transport and transfer robots through a series of technical measures, including drive unit posture detection, load monitoring, condition-based speed control selection, collaborative braking control combining master-slave control and deviation coupling, and load platform vibration monitoring. It achieves good multi-motor coordination, adapts to complex underground working conditions, shortens braking distance, and improves the braking performance and operational stability of coal mine auxiliary transport and transfer robots, providing a safer and more reliable guarantee for underground material transportation and personnel and equipment transport.

[0210] Of course, 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for coordinated braking control of a PMSM (Potentially Integrated Motor) auxiliary transport and transfer robot in coal mines, characterized in that, Includes the following steps: Drive unit attitude detection steps: Accelerometers installed at the ends of key drive shafts and chassis support points of the drive unit are used to monitor the vibration attitude of the drive unit in real time; tilt sensors installed on the main frame of the drive unit are used to measure the angle between each drive unit and the horizontal plane. ; The initial speed of each motor is obtained by a position encoder integrated into the output shaft of the drive motor. When the angle between the drive unit and the horizontal plane When the angle between the drive unit and the horizontal plane exceeds a preset threshold, the drive unit is determined to be in inclined track operation; when the angle between the drive unit and the horizontal plane exceeds a preset threshold, the drive unit is determined to be in inclined track operation. When the value is less than or equal to a preset threshold, the drive unit is determined to be in a straight-rail operating condition. Drive unit load monitoring steps: Measure the real-time output torque using a torque sensor installed at the connection between the drive motor and the reducer; Speed ​​control selection steps: group three adjacent drive units together, select the drive unit in the middle position of each group as the master drive unit of the group, and set the remaining drive units as slave drive units. Obtain the horizontal angle between the first drive unit in the first drive group and the last drive unit in the last drive group; when the angle between the first drive unit and the horizontal plane is greater than the angle between the last drive unit and the horizontal plane, the first drive group is controlled first, and the output speed of the previous drive group is used as the desired input speed for the subsequent drive group; when the angle between the first drive unit and the horizontal plane is less than the angle between the last drive unit and the horizontal plane, the last drive group is controlled first, and the output speed of the next drive group is used as the desired input speed for the preceding drive group. Coordinated braking control steps: Coordinated braking is achieved by combining master-slave control with deviation coupling control; a position compensation signal is generated by processing the difference between the desired speed and the actual speed of the main motor through a position compensator. For the first drive group, the first position compensation signal is calculated: For the second drive group, calculate the second position compensation signal: ,in, For the desired rotational speed, This refers to the actual speed of the main motor in the first drive group. This refers to the actual speed of the main motor of the second drive group. , , , For control parameters; based on the actual speed change of the motor, a speed deviation compensation signal is generated through a coupling link, and the proportional error term between each motor in the drive group is calculated. For the first drive group, the speed deviation compensation value is... For the second drive group, the speed deviation compensation value ,in, to For the speed of each motor, to As a scaling factor, , , , The dynamic gain adjustment coefficient is used to feed back the position compensation signal and the speed deviation compensation signal to the speed controller of the main motor to achieve load compensation. Operational stability assessment steps: Data from acceleration and tilt sensors are collected; the data undergoes filtering, amplification, and standardization; real-time calibration is performed using an embedded algorithm; and stability indices are calculated by combining acceleration and tilt data. ,in, As a stability indicator, The root mean square value of acceleration. For acceleration threshold, The rate of change of tilt angle, and For weighting coefficients; when When the value is greater than 1, adjust the control parameters; dynamically adjust the load safety threshold based on torque data; evaluate the speed synchronization error between motors and determine whether each proportional error term has converged to the preset range; when the proportional error term has not converged to the preset range, adjust the dynamic gain adjustment coefficient according to the following formula: ,in, To adjust the coefficient, The preset error tolerance is used; the vibration amplitude of the load platform during the braking process is continuously monitored, and when the vibration amplitude exceeds the safety threshold, the control parameters are adjusted to reduce the vibration amplitude.

2. The method according to claim 1, characterized in that, The speed control selection step also includes introducing a transition coefficient. Used to smooth the process of switching operating conditions: ,in, For the target speed of the non-priority group, For the output speed of the priority group, For the original expected speed, This is the transition coefficient, with a value ranging from 0 to 1.

3. The method according to claim 1, characterized in that, In the cooperative braking control step, the proportional error term satisfies the following convergence condition: , , , .

4. The method according to claim 1, characterized in that, The operational stability assessment step also includes: monitoring the load torque of each drive unit in real time using torque sensors and calculating the average load rate. ,in, The actual torque of the i-th drive unit is... For rated torque, The number of drive units; the control parameters of the position compensation signal and speed deviation compensation signal are adjusted according to the average load rate.

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