Multi-motor synchronous control system and method of TBM main drive system simulation test bench

Abstract

The invention relates to a multi-motor synchronous control system of a TBM (tunnel boring machine) main driving system simulation test bed, which comprises a plurality of motors mounted on the TBM main driving system simulation test bed, each motor is provided with a pinion, each pinion is meshed with an outer gear ring of an upper end main slewing bearing, each motor is connected with a rotary transformer, and the rotary transformer is connected with the TBM main driving system simulation test bed. The receiving module receives pulse signals of each motor; every two motors form a group, each group of motors is connected with one servo variable frequency driver, each servo variable frequency driver is interconnected with the synchronous motion control unit through an EtherCAT network, a virtual shaft is arranged in the synchronous motion control unit, the synchronous motion control unit is connected with the PLC control unit, the PLC control unit is a master station, and the synchronous motion control unit is a slave station. And the PLC control unit is connected with the touch screen. The invention further provides a multi-motor synchronous control method of the TBM main drive system simulation test bed. According to the invention, synchronization errors and system buffeting of multi-motor control are reduced, and the response speed and control precision of the system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of motor synchronous control, and particularly to a multi-motor synchronous control system and method for a simulation test bench of a TBM main drive system. Background Art

[0002] During the tunneling process of a full-face tunnel boring machine (TBM), due to the complex and changeable geological environment and the multi-field coupling effect, the drive motors in the main drive system may experience severe torque fluctuations, which can easily lead to torque imbalance of the drive motors and even cause abnormal damage to key components such as drive shafts. Therefore, realizing the synchronous control of multiple motors in the main drive system is one of the key technologies to ensure the safe and reliable operation of the TBM. Given the harsh working environment, narrow working space and complex structural space of the TBM main drive system, it is difficult to obtain the vibration, temperature and other parameter states of the main drive system during actual working conditions. Usually, these parameters are measured through a test bench, and the TBM main drive system simulation test bench can simulate the TBM main drive system and provide experimental parameters for simulated operation.

[0003] Considering the transmission characteristics of the TBM cutter head (such as Figure 1 the upper main slewing bearing shown), the connection between each motor and the gear is rigid, which leads to the forced synchronization phenomenon between the motors. However, this speed synchronization is passive. Due to the meshing effect between the gears, although the given speeds of each motor are the same, the output torques may be different. This may cause the speed of individual motors to be too fast, resulting in a sharp increase in their loads, increasing the heat generation of the motors, and even burning out the motors in severe cases.

[0004] Currently, the main synchronous control methods adopted by the TBM main drive control system include parallel control and master-slave control, etc. Although these methods are simple and easy to implement, the inherent coupling characteristics of the system mean that the synchronization of the entire system depends on the accuracy of the single-motor control technology and the stability of the load. When there is multi-motor partial load, the system is prone to fluctuations or unable to reach the balanced state, thus affecting the normal operation of the TBM. In order to improve the synchronous performance of the drive system, a control structure of virtual axis deviation coupling is adopted. However, due to the error between the input given of the virtual axis and the output of the drive motor, and the corresponding coupling relationship between the mechanical parts of the test bench, this will reduce the synchronization of the drive system. Therefore, there is an urgent need to develop a multi-motor synchronous control system and method based on the TBM main drive system simulation test bench. Summary of the Invention

[0005] In order to solve the above problems, the object of the present invention is to provide a multi-motor synchronous control system and method for a simulation test bench of a TBM main drive system.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The multi-motor synchronous control system of the TBM main drive system simulation test bench includes multiple motors installed on the TBM main drive system simulation test bench. Each motor is provided with a pinion gear, and each pinion gear meshes with the external gear ring of the upper main slewing bearing. Each motor is connected to a resolver for receiving the pulse signals of each motor; every two motors form a group, and each group of motors is connected to a servo frequency converter. Each servo frequency converter is interconnected with the synchronous motion control unit through an EtherCAT network. A virtual axis is provided in the synchronous motion control unit, and the synchronous motion control unit is connected to the PLC control unit. The PLC control unit is the master station, and the synchronous motion control unit is the slave station. The PLC control unit is connected to the touch screen.

[0007] Further, the PLC control unit is additionally connected to the pressure sensor, the drive-end torque sensor, and the load-end torque sensor of the TBM main drive system simulation test bench. At the same time, the PLC control unit is communicatively connected to the computer.

[0008] Further, the motor is an AC permanent magnet synchronous motor with a rated power of 3.7 kW, a speed of 2000 r / min, and a maximum torque of 25 N·m.

[0009] Further, the number of the motors is six.

[0010] The present invention also provides a multi-motor synchronous control method for the TBM main drive system simulation test bench, which is implemented by using the multi-motor synchronous control system of the TBM main drive system simulation test bench, and includes the following steps:

[0011] S1, establish an electromechanical coupling mechanism model of the main drive system;

[0012] S2, set a control structure combining deviation coupling and virtual axis in the PLC control unit to control the output speed and torque values of each motor, and feedback them to the input end of the virtual axis in the synchronous motion control unit;

[0013] S3, establish a mathematical model of the motor on the d-q axis, construct a super-twisting sliding mode controller, design an improved non-singular fast terminal sliding mode surface, and introduce an adaptive power function into the non-singular fast terminal sliding mode exponential reaching law;

[0014] S4, establish a super-twisting sliding mode disturbance observer model and an extended super-twisting model of the motor speed loop, design an extended sliding mode disturbance observer, and discretize the extended sliding mode disturbance observer. Real-time observe the part including external disturbances and parameter perturbations in the super-twisting sliding mode controller through the super-twisting sliding mode disturbance observer, and feedback the observed value to the super-twisting sliding mode controller to achieve the synchronous control of each motor.

[0015] Furthermore, the electromechanical coupling mechanism model of the main drive system described in step S1 is as follows:

[0016]

[0017] In the formula, i = 1, 2…6; k ld represents the torsional connection stiffness of the upper main slewing bearing; k mpo represents the torsional stiffness of the pinion and the motor shaft; k pmi represents the time-varying meshing stiffness of the i-th pinion and the outer gear ring under different overturning degrees;

[0018] r bm represents the base circle radius of the pinion; r bd is the base circle radius of the outer gear ring;

[0019] C ld represents the torsional damping of the upper main slewing bearing; C mpo represents the torsional damping between the pinion and the shaft; C pmi represents the meshing damping of the i-th pinion and the outer gear ring under different overturning degrees; C psi represents the torsional damping of the motor;

[0020] I l represents the moment of inertia of the upper main slewing bearing; I d represents the moment of inertia of the outer gear ring; I mi represents the moment of inertia of the i-th pinion; J i represents the moment of inertia of the i-th motor;

[0021] θ l represents the torque displacement of the upper main slewing bearing; θ d represents the torque displacement of the outer gear ring; θ mi represents the torque displacement of the i-th pinion; θ si represents the torque displacement of the i-th motor;

[0022] T si represents the output torque of the i-th motor; T l represents the equivalent total torque borne by the upper main slewing bearing; T ei represents the electromagnetic torque of the i-th motor; D pmi represents the meshing damping force between the i-th pinion and the outer gear ring; F pmi represents the dynamic meshing force between the i-th pinion and the outer gear ring.

[0023] Furthermore, step S3 specifically includes the following steps:

[0024] S301, establish the mathematical model of the motor on the d-q axis:

[0025]

[0026] where: u d represents the d-axis voltage, u q represents the q-axis voltage; L d represents the d-axis inductance, L q represents the q-axis inductance; i d represents the d-axis current, i q represents the q-axis current; R s represents the stator resistance, ψ represents the permanent magnet flux linkage, ω e represents the rotor electrical angular velocity; f d and f q respectively represent the disturbances caused by changes in model parameters and external load changes;

[0027] f d and f q are defined as:

[0028]

[0029] where, ΔR s 、ΔL q 、ΔL d and Δψ respectively represent the change values of R s 、L q 、L d and ψ when the model parameters and external load change;

[0030] S302, in order to estimate the unknown parameters existing in the motor, the following superlocal model is adopted:

[0031]

[0032] where, y and u respectively represent the system output and control input, x represents the state variable of the system, y (v) is the v-th derivative of y and v≥1, g(x) is a nonlinear Lipschitz bounded function, only related to x, K is a non-zero physical constant gain to be determined, such that Ku has the same order as x;

[0033] S303, construct a motor superlocal sliding mode controller, specifically:

[0034]

[0035] where, α ω represents the q-axis current gain to be designed, β ω represents the rotational speed gain to be designed, F ω represents the set of parameter perturbations, load fluctuations and other unknown parameters in the system;

[0036] S304. Design an improved non-singular fast terminal sliding mode surface, specifically as follows:

[0037] 1) Define the rotational speed error e as: e = ω r - ω e ;

[0038] where ω r represents the target rotational speed of the motor, and ω e represents the electrical angular velocity of the rotor;

[0039] 2) Define the rotational speed error e as a system state variable:

[0040]

[0041] where x1 represents the system state error;

[0042] 3) Define the improved non-singular fast terminal sliding mode surface s as:

[0043]

[0044] where p, q, λ2, and λ1 are constants, and p > 0, q > 0, 0 < λ2 < 2, λ2 < λ1, and sgn() is the sign function;

[0045] 4) Introduce an adaptive power function into the non-singular fast terminal sliding mode exponential reaching law:

[0046]

[0047] where k1, k2, and α are positive constants to be designed;

[0048] When the system state is about to reach the sliding mode surface, i.e., |s| < 1, the variable speed reaching term k1(|x1||s|) 1-αsgn(1-|s|) sgn(s) plays a dominant role, while the exponential reaching term k2|s| 1+α sgn(s) will quickly approach 0. Obviously, k1(|x1||s|) 1+α and k2|s| 1+α are both respectively less than k1|s| 1-α and k2s. As |s| continues to decrease, the system chattering is effectively reduced on the premise of ensuring convergence.

[0049] Furthermore, step S4 specifically includes the following steps:

[0050] S401. Establish a super-twisting sliding mode disturbance observer model:

[0051]

[0052] where s1, u1 are state variables, and β1, β2 are sliding mode gain coefficients;

[0053] S402. Based on the motor's super-local model, establish an extended super-local model of the motor speed loop according to the input and output of the motor speed loop control:

[0054]

[0055] where R(t) is the rate of change of F ω of;

[0056] S403. Design an extended sliding mode disturbance observer, specifically:

[0057]

[0058] where is the real-time estimated value of the motor speed by the observer; is the real-time estimated value of the total unknown part of the system by the observer; u smo is the sliding mode function to be designed; l is the sliding mode function u smo gain;

[0059] Define the observer errors e1 and e2 as:

[0060] When the super-twisting sliding mode disturbance observer error is achieved to be 0, and the observer converges asymptotically;

[0061] Satisfy In the formula, ε is an arbitrary positive constant;

[0062] Based on s1 = e1, discretize the super-twisting sliding mode disturbance observer to obtain:

[0063]

[0064] where T is the sampling period and k is a positive constant;

[0065] S404. Through the super-twisting sliding mode disturbance observer, real-time observe the part containing external disturbances and parameter perturbations in the super-local sliding mode controller, and feedback the observed value e2 to the super-local sliding mode controller to achieve the synchronous control of each motor.

[0066] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0067] 1. The present invention proposes a multi - motor synchronous control method. By dividing the driving motors into regions, every two motors are divided into a group and connected to a servo - frequency converter. After the multi - motor region division in the present invention, the system exhibits coupling characteristics, and an improved control structure combining deviation coupling and virtual spindle is adopted, ensuring synchronous performance while being able to quickly generate synchronous compensation to make up for the adjustment delay. Compared with the multi - motor master - slave control strategy in the prior art, the transmission delay of the motor speed and torque signals is significantly reduced, thus improving the dynamic response characteristics of the system. The present invention can simulate the partial load and overload phenomena that occur when the motor position and speed tracking in the actual operation of the TBM main drive system are affected by the nonlinearity of the friction backlash.

[0068] 2. The present invention is applicable to the synchronous control of more than two motors. Based on the original virtual - axis control strategy, the present invention simplifies the system design, solves the problem of large interference in the virtual - axis control method under the application of high - power systems, improves the adaptability of the system, reduces the maintenance difficulty, and enhances the response speed and control accuracy of the system.

[0069] 3. The present invention designs a speed disturbance observer and modifies the q - axis current reference value and the actual speed reference of each motor based on the feedback compensation signal processed by the super - twisting sliding - mode observer. The present invention further improves the speed dynamic performance of the motor itself by using an improved sliding - mode controller.

[0070] 4. The present invention incorporates an adaptive power function into the terminal sliding - mode exponential reaching law and designs a new type of adaptive reaching law to adjust the system state variables. By constructing a super - twisting sliding - mode disturbance observer, the present invention improves the system's ability to observe disturbances and the sensitivity of motor speed and feedback. In the case of parameter disturbances and load mutations, the system can real - time estimate the total unknown part and feedback it to the speed control link, effectively reducing the system synchronous error. On the premise of ensuring convergence, the present invention effectively reduces system chattering. Description of the Drawings

[0071] The drawings described herein are used to provide a further understanding of the present invention and form a part of this application. The schematic examples and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention;

[0072] Figure 1 It is a schematic structural diagram of the TBM main drive system simulation test bench in the present invention;

[0073] Figure 2 It is a structural diagram of the multi - motor synchronous control system of the TBM main drive system simulation test bench in the present invention;

[0074] Figure 3This is the structural diagram of the transmission torque coupling between the pinion of the motor and the external gear ring of the upper main slewing bearing in the present invention;

[0075] Figure 4 This is the electrical control principle block diagram of the multi-motor synchronous control system of the TBM main drive system simulation test bench in the present invention;

[0076] Figure 5 This is the flow chart of the super-twisting sliding mode disturbance observer in the present invention for real-time estimating the unknown part of the system and feedback compensation;

[0077] Figure 6 This is the experimental result diagram of observing the torque output of six motors under sudden load addition in the present invention;

[0078] In the figure: 1. Motor; 2. Pinion; 3. Upper main slewing bearing; 4. External gear ring; 5. Servo frequency conversion driver; 6. Synchronous motion control unit; 7. PLC control unit; 8. Touch screen; 9. Pressure sensor; 10. Driving end torque sensor; 11. Load end torque sensor; 12. Computer. Specific embodiments

[0079] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0080] Refer to Figure 1 , the TBM main drive system simulation test bench in the present invention is a multi-source signal online monitoring simulation test bench of a TBM main drive system with a patent publication number of CN116577096A. The multi-motor synchronous control system and method of the present invention are both implemented based on the TBM main drive system simulation test bench.

[0081] Embodiment 1

[0082] Refer to Figure 1 and Figure 2, the multi-motor 1 synchronous control system of the TBM main drive system simulation test bench, includes multiple motors 1 installed on the TBM main drive system simulation test bench. Each motor 1 is equipped with a pinion 2, and each pinion 2 meshes with the external gear ring 4 of the upper main slewing bearing 3 respectively. Each motor 1 is connected to a resolver (not shown in the figure) for receiving the pulse signals of each motor 1; every two motors 1 form a group, and each group of motors 1 is connected to a servo frequency converter 5. Each servo frequency converter 5 is interconnected with the synchronous motion control unit 6 through the EtherCAT network. There is a virtual axis in the synchronous motion control unit 6. The virtual axis feeds back the current loop, position loop, and torque loop data of the motor 1 at the output end of the servo frequency converter to the input end for adjustment. The synchronous motion control unit 6 is connected to the PLC control unit 7. The PLC control unit 7 is the master station, and the synchronous motion control unit 6 is the slave station. The PLC control unit 7 is connected to the touch screen 8.

[0083] The touch screen 8 is provided with a human-machine interaction interface for setting the parameters of each motor 1 and the start-stop and speed-regulating commands issued by the user.

[0084] Each resolver transmits the pulse signals of each motor 1 received to the servo frequency converter 5. Each servo frequency converter 5 identifies the signals transmitted by the resolver and transmits them to the synchronous motion control unit 6 through the EtherCAT network; the PLC control unit 7 receives the start-stop and speed-regulating commands issued by the user and sends them to the synchronous motion control unit 6. The synchronous motion control unit 6 controls the rotation of the virtual axis, sends speed-regulating signals and start-stop control signals to the servo frequency converter 5. The multiple motors 1 are interlocked with the virtual axis, and automatically adjust the torque output of the six motors 1 according to the set parameters of the current loop, position loop, and torque loop of the virtual axis.

[0085] The PLC control unit 7 is additionally connected to the pressure sensor 9, the drive-end torque sensor 10, and the load-end torque sensor 11 of the TBM main drive system simulation test bench. At the same time, the PLC control unit 7 is communicatively connected to the computer 12.

[0086] The number of pressure sensors 9 is 3, the number of drive-end torque sensors 10 is 6, and the number of load-end torque sensors 11 is one. The drive-end torque sensor 10 real-time collects the output torque data of each motor 1, the load-end torque sensor 11 real-time collects the input torque data of the load device, and the pressure sensor 9 implements the collection of the pressure data of the loading hydraulic cylinder and transmits it to the PLC control unit 7, and observes the operation status of the equipment in real time through the touch screen 8.

[0087] The motor 1 is an AC permanent magnet synchronous motor 1 with a rated power of 3.7 kW, a speed of 2000 r / min, and a maximum torque of 25 N·m.

[0088] The number of the motors 1 is six.

[0089] In the present invention, the multi-motor 1 synchronous control system of the TBM main drive system simulation test bench can achieve a stable closed-loop speed control state, synchronously collect the data required for the experiment, and realize fast, stable and accurate numerical storage and recording. In this embodiment, the PLC control unit 7 is a programmable controller system with Lanpufeng 2000 as the master station and the synchronous motion control unit 6 as the slave station. The programmable controller IO adopts DC24V acquisition and control. The PLC control unit 7 uses CODESYS programming with strong versatility and portability, which is easy to modify the program in the later stage. The touch screen 8 has a digital display human-machine interaction interface, which is used to set the enable interlock of each motor 1, and send speed regulation signals and start-stop control signals to each servo frequency converter 5 through the PLC control unit 7 as the master station according to the start-stop and speed regulation instructions issued by the user. The experimenter can monitor the operation of the program through the touch screen 8, and can also perform hardware diagnosis. The touch screen 8 communicates with the PLC control unit 7, collects, processes, stores and displays the data obtained by networking, and customizes the control screen to facilitate the operation of the experimenter. The automation level of the electrical control system of the TBM main drive system multi-functional test bench is the field level, and the field bus control technology using the MODBUS protocol is adopted. And the PLC control unit 7 communicates with the computer 12 through the industrial Ethernet protocol, and its automation level can be raised to the monitoring level and the management level to realize the remote test and monitoring of the shield machine.

[0090] The technical data involved in the multi-motor 1 synchronous control system of the present invention are shown in Table 1:

[0091] Table 1 Technical parameters of the multi-motor synchronous control system

[0092]

[0093] Embodiment 2

[0094] The multi-motor synchronous control method of the TBM main drive system simulation test bench is realized by using the multi-motor synchronous control system of the TBM main drive system simulation test bench described in Embodiment 1, and includes the following steps:

[0095] Referring to Figures 1 - 3 , S1, establish the electromechanical coupling mechanism model of the main drive system:

[0096]

[0097] where i = 1, 2... 6; k ld represents the torsional connection stiffness of the upper main slewing bearing 3; k mpo represents the torsional stiffness of the pinion 2 and the motor shaft; k pmi represents the time-varying meshing stiffness of the i-th pinion 2 and the external gear ring 4 under different overturning degrees;

[0098] r bm represents the base circle radius of the pinion 2; r bd is the base circle radius of the external gear ring 4;

[0099] C ld represents the torsional damping of the upper main slewing bearing 3; C mpo represents the torsional damping between the pinion 2 and the shaft; C pmi represents the meshing damping between the i-th pinion 2 and the external gear ring 4 under different overturning degrees; C psi represents the torsional damping of the motor 1;

[0100] I l represents the moment of inertia of the upper main slewing bearing 3; I d represents the moment of inertia of the external gear ring 4; I mi represents the moment of inertia of the i-th pinion 2; J i represents the moment of inertia of the i-th motor 1;

[0101] θ l represents the torque displacement of the upper main slewing bearing 3; θ d represents the torque angular displacement of the external gear ring 4; θ mi represents the torque angular displacement of the i-th pinion 2; θ si represents the torque angular displacement of the i-th motor 1;

[0102] T si represents the output torque of the i-th motor 1; T l represents the equivalent total torque borne by the upper main slewing bearing 3; T ei represents the electromagnetic torque of the i-th motor 1; D pmi represents the meshing damping force between the i-th pinion 2 and the external gear ring 4; F pmi represents the dynamic meshing force between the i-th pinion 2 and the external gear ring 4;

[0103] Refer to Figure 4 , S2, set the control structure combining deviation coupling and virtual axis in the PLC control unit, control the output speed and torque values of each motor 1, feedback to the input end of the virtual axis in the synchronous motion control unit, and transfer the output of the synchronous motion control unit to the servo frequency converter 5 to achieve the compensation and correction of the speed reference value, specifically including the following steps:

[0104] Refer to Figure 4The control structure combining deviation coupling with a virtual axis, the PI controller of the virtual axis speed loop, outputs a set value to six motors 1, and at the same time accepts the feedback speed error. The speed error is weighted and transformed to take the extreme value and the mean value for coupling as the synchronization error. The synchronization error is multiplied by different weights and then added to obtain the synchronization compensation amount. The synchronization compensation amount is output to the forward path of the current loop of each motor 1 to achieve error compensation, ensuring that the control parameters of the six driving motors 1 are basically the same as those of the virtual axis;

[0105] S3. Establish the mathematical model of motor 1 on the d-q axis, construct a super-twisting sliding mode controller, and design an improved non-singular fast terminal sliding mode surface. An adaptive power function is introduced into the non-singular fast terminal sliding mode exponential reaching law, which specifically includes the following steps:

[0106] S301. Establish the mathematical model of motor 1 on the d-q axis:

[0107]

[0108] where: u d represents the d-axis voltage, and u q represents the q-axis voltage; L d represents the d-axis inductance, and L q represents the q-axis inductance; i d represents the d-axis current, and i q represents the q-axis current; R s represents the stator resistance, ψ represents the permanent magnet flux linkage, and ω e represents the rotor electrical angular velocity; f d and f q respectively represent the disturbances caused by the changes in model parameters and external loads;

[0109] where, f d and f q are defined as:

[0110]

[0111] where, ΔR s 、ΔL q 、ΔL d and Δψ respectively represent the change values of R s 、L q 、L d and ψ when the model parameters and external loads change;

[0112] S302. In order to estimate the unknown parameters existing in motor 1, the following super-twisting model is adopted:

[0113]

[0114] where \(y\) and \(u\) represent the system output and control input respectively, \(x\) represents the state variable of the system, \(y^{(v)}\) (v) is the \(v\)-th derivative of \(y\) with \(v\geq1\), \(g(x)\) is a non-linear Lipschitz bounded function, which only depends on \(x\), \(K\) is a non-zero physical constant gain to be determined, such that \(Ku\) has the same order as \(x\);

[0115] S303. Construct a motor super-twisting sliding mode controller, specifically:

[0116]

[0117] where \(\alpha\) ω represents the \(q\)-axis current gain to be designed, \(\beta\) ω represents the speed gain to be designed, \(F\) ω represents the set of parameter perturbations, load fluctuations and other unknown parameters in the system;

[0118] S304. Design an improved non-singular fast terminal sliding mode surface, specifically:

[0119] 1) Define the speed error \(e\) as: \(e=\omega_{ref}-\omega\) r -\(\omega\) e ;

[0120] where \(\omega_{ref}\) r represents the target speed of motor 1 (the speed value set by the virtual axis), \(\omega\) e represents the electrical angular velocity of the rotor;

[0121] 2) Define the speed error \(e\) as a system state variable:

[0122]

[0123] where \(x_1\) represents the system state error;

[0124] 3) Define the improved non-singular fast terminal sliding mode surface \(s\) as:

[0125]

[0126] where \(p\), \(q\), \(\lambda_2\) and \(\lambda_1\) are constants, and \(p > 0\), \(q > 0\), \(0 < \lambda_2 < 2\), \(\lambda_2 < \lambda_1\), \(\text{sgn}()\) is the sign function;

[0127] 4) Introduce an adaptive power function into the non-singular fast terminal sliding mode exponential reaching law:

[0128]

[0129] where \(k_1\), \(k_2\) and \(\alpha\) are positive constants to be designed;

[0130] When the system state is about to reach the sliding mode surface, i.e., |s| < 1, the variable speed reaching term k1(|x1||s|) 1-αsgn(1-|s|) sgn(s) plays a dominant role, while the exponential reaching term k2|s| 1+α sgn(s) will rapidly approach 0. Obviously, k1(|x1||s|) 1+α and k2|s| 1+α are respectively less than k1|s| 1-α and k2s. As |s| continues to decrease, on the premise of ensuring convergence, the system chattering is effectively reduced;

[0131] S4. Establish a super-twisting sliding mode disturbance observer model and an extended super-local model of the motor speed loop, design an extended sliding mode disturbance observer, and discretize the extended sliding mode disturbance observer. The super-twisting sliding mode disturbance observer is used to observe in real time the part containing external disturbances and parameter perturbations in the super-local sliding mode controller, and the observed value e2 is fed back to the super-local sliding mode controller to achieve the synchronous control of each motor 1 (refer to Figure 5 ), which specifically includes the following steps:

[0132] S401. Establish a super-twisting sliding mode disturbance observer model:

[0133]

[0134] where s1 and u1 are state variables, and β1 and β2 are sliding mode gain coefficients;

[0135] S402. Based on the super-local model of the motor, establish an extended super-local model of the motor speed loop according to the input and output of the speed loop control of motor 1:

[0136]

[0137] where R(t) is the rate of change of F ω ;

[0138] S403. Design an extended sliding mode disturbance observer, specifically:

[0139]

[0140] where, is the real-time estimated value of the speed of motor 1 by the observer; is the real-time estimated value of the total unknown part of the system by the observer; u smo is the sliding mode function to be designed; l is the gain of the sliding mode function u smo ;

[0141] Define the observer errors e1 and e2 as:

[0142] When The error of the super-twisting sliding mode disturbance observer is made zero, and the observer converges asymptotically;

[0143] Satisfy where ε is an arbitrary positive constant;

[0144] Based on s1 = e1, discretizing the extended sliding mode disturbance observer equation, we can obtain:

[0145]

[0146] where T is the sampling period and k is a positive constant;

[0147] S404. The super-twisting sliding mode disturbance observer is used to observe in real time the part containing external disturbances and parameter perturbations in the super-local sliding mode controller, and the observed value e2 is fed back to the super-local sliding mode controller to achieve the synchronous control of each motor 1.

[0148] When the present invention performs multi-motor synchronous control, first, the TBM main drive system multi-functional test bench is powered on. On the touch screen 8 on the console, one-key enabling and one-key interlocking of the six motors 1 are realized, and the rotation speed of the TBM main drive system test bench is set to 2 m / s. A computer 12 communicates with the PLC control unit 7, and the Ethernet IP address of the CODESYS software is set to 192.168.5.100 to achieve data synchronization with the PLC control unit 7. At this time, instructions can be issued to the test bench control system through the PLC control unit 7.

[0149] Using the EASY software, data synchronization is also performed with the synchronous motion control unit 6 in the test bench. The IP address is set the same as that of the above PLC control unit 7. After the synchronous motion control unit 6 receives the synchronous instruction issued by the PLC control unit 7, the synchronous motion control unit 6 sets the parameters of the internal virtual axis, controls the rotation of the virtual axis, and the six motors 1 are interlocked with the virtual axis. The torque output of the six motors 1 is automatically adjusted according to the set parameters of the current loop, position loop, and torque loop of the virtual axis. Without any load, the rotation speed and torque of the six motors 1 are basically the same, achieving multi-motor synchronous control.

[0150] Start the hydraulic system of the test bench, push the hydraulic push rod to apply pressure, and push down by 10 N. At this time, the synchronous motion control unit 6 quickly responds to adjust the output of the current loop, position loop, and torque loop of the six motors 1 to achieve the synchronous control of the six motors 1.

[0151] According to the above steps, the rotational speed and torque values of each motor 1 can be obtained. The output of the synchronous motion control unit 6 and the speed command act together on the speed command of each servo frequency converter 5 loop to achieve multi-feedback control of rotational speed, torque, and displacement, thereby realizing the rotational speed synchronization control, torque balance, and identical displacement of the motors 1 in multiple loops.

[0152] Set the target rotational speed of motor 1 to 2000 r / s, and set the load mutation range of motor 1 to 3 - 20 N at 0.5 s. The model parameters are shown in Table 2.

[0153] Table 2 Model Parameters of Motor 1

[0154]

[0155] Apply the parameters in Table 4 to Figure 4 and Figure 5 the designed control model of, and the experimental results obtained are as shown in Figure 6 At t = 0.5 s, a sudden load is applied to six motors 1, and the load torque is T l = 10 N. As can be seen from Figure 6 , for the super-twisting sliding mode control during load disturbance, the speed fluctuation is small, and the synchronization response time is short. Moreover, under the observation of the improved super-umbrella sliding mode controller and the super-twisting sliding mode disturbance observer, the torque curve has a fast response speed, small oscillation, short recovery time, and good motor synchronization effect.

[0156] It can be seen from this that under load, through experimental verification, the synchronous control method of the present invention can control the torque balance time of each motor 1 within 0.1 s, has a fast response time, and good synchronization effect, and can meet the working requirements of the TBM main drive system.

[0157] The above are only the preferred examples of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made to the present invention shall be included within the protection scope of the present invention.

Claims

1. The multi-motor synchronous control system of the TBM main drive system simulation test bench is characterized in that, It includes multiple motors installed on the simulation test bench of the TBM main drive system. Each motor is equipped with a pinion gear, and each pinion gear meshes with the external gear ring of the upper main slewing bearing. Each motor is connected to a resolver for receiving the pulse signals of each motor; every two motors form a group, and each group of motors is connected to a servo variable-frequency drive. Each servo variable-frequency drive is interconnected with the synchronous motion control unit through an EtherCAT network. A virtual axis is provided in the synchronous motion control unit, and the synchronous motion control unit is connected to the PLC control unit. The PLC control unit is the master station, and the synchronous motion control unit is the slave station. The PLC control unit is connected to the touch screen.

2. The multi-motor synchronous control system of the TBM main drive system simulation test bench according to claim 1, characterized in that, The PLC control unit is additionally connected to the pressure sensor, the driving-end torque sensor, and the load-end torque sensor of the TBM main drive system simulation test bench. At the same time, the PLC control unit is communicatively connected to the computer.

3. The multi-motor synchronous control system of the TBM main drive system simulation test bench according to claim 1, characterized in that, The motor is an AC permanent magnet synchronous motor with a rated power of 3.7 kW, a speed of 2000 r / min, and a maximum torque of 25 N·m.

4. The multi-motor synchronous control system of the TBM main drive system simulation test bench according to claim 1, characterized in that, The number of the motors is six.

5. The multi-motor synchronous control method of the TBM main drive system simulation test bench is implemented by using the multi-motor synchronous control system of the TBM main drive system simulation test bench described in any one of claims 1-4, and is characterized in that, It includes the following steps: S1. Establish the electromechanical coupling mechanism model of the main drive system; S2. Set the control structure combining deviation coupling and virtual axis in the PLC control unit to control the output speed and torque values of each motor and feedback them to the input end of the virtual axis in the synchronous motion control unit; S3. Establish the mathematical model of the motor on the d-q axis, construct the super-twisting sliding mode controller, design the improved non-singular fast terminal sliding mode surface, and introduce the adaptive power function into the non-singular fast terminal sliding mode exponential reaching law; S4. Establish the super-twisting sliding mode disturbance observer model and the extended super-twisting model of the motor speed loop, design the extended sliding mode disturbance observer, discretize the extended sliding mode disturbance observer, and use the super-twisting sliding mode disturbance observer to observe in real time the part including external disturbances and parameter perturbations in the super-twisting sliding mode controller and feedback the observed values to the super-twisting sliding mode controller to realize the synchronous control of each motor.

6. The multi-motor synchronous control method of the TBM main drive system simulation test bench according to claim 5, characterized in that The electromechanical coupling mechanism model of the main drive system described in step S1 is: Where \(i = 1, 2,\cdots, 6\); \(k\) ld represents the torsional connection stiffness of the upper main slewing bearing; \(k\) mpo represents the torsional stiffness of the pinion and the motor shaft; \(k\) pmi represents the time-varying meshing stiffness of the \(i\)-th pinion and the external gear ring under different tilting degrees; r bm represents the base circle radius of the pinion; r bd is the base circle radius of the external gear ring; C ld represents the torsional damping of the upper main slewing bearing; C mpo represents the torsional damping between the pinion and the shaft; C pmi represents the meshing damping between the i-th pinion and the external gear ring under different overturning degrees; C psi represents the torsional damping of the motor; I l represents the moment of inertia of the upper main slewing bearing; I d represents the moment of inertia of the external gear ring; I mi represents the moment of inertia of the i-th pinion; J i represents the moment of inertia of the i-th motor; θ l represents the torque displacement of the upper main slewing bearing; θ d represents the torque angular displacement of the external gear ring; θ mi represents the torque angular displacement of the i-th pinion; θ si represents the torque angular displacement of the i-th motor; T si represents the output torque of the i-th motor; T l represents the equivalent total torque borne by the upper main slewing bearing; T ei represents the electromagnetic torque of the i-th motor; D pmi represents the meshing damping force between the i-th pinion and the external gear ring; F pmi represents the dynamic meshing force between the i-th pinion and the external gear ring.

7. The multi-motor synchronous control method for the TBM main drive system simulation test bench according to claim 5, characterized in that, The specific steps of step S3 include the following: S301. Establish the mathematical model of the motor on the d-q axis: where: u d represents the d-axis voltage, u q represents the q-axis voltage; L d represents the d-axis inductance, L q represents the q-axis inductance; i d represents the d-axis current, i q represents the q-axis current; R s represents the stator resistance, ψ represents the permanent magnet flux linkage, ω e represents the rotor electrical angular velocity; f d and f q respectively represent the disturbances caused by changes in model parameters and external load changes; f d and f q are defined as: Among them, ΔR s , ΔL q , ΔL d and Δψ respectively represent the change values of R s , L q , L d , and ψ when the model parameters change and the external load changes; S302. To estimate the unknown parameters existing in the motor, use the following super-twisting model: where y and u represent the system output and control input respectively, x represents the state variable of the system, and y (v) is the v-th derivative of y with v≥1, g(x) is a non-linear Lipschitz bounded function that depends only on x, K is a non-zero physical constant gain to be determined such that Ku has the same order as x; S303. Construct the super-twisting sliding mode controller of the motor, specifically: Among them, α ω represents the q-axis current gain to be designed, β ω represents the rotational speed gain to be designed, and F ω represents the set of parameter perturbations, load fluctuations, and other unknown parameters in the system; S304. Design the improved non-singular fast terminal sliding mode surface, specifically: 1) Define the rotational speed error e as: e = ω r - ω e ; Among them, ω r represents the target rotational speed of the motor, and ω e represents the electrical angular velocity of the rotor; 2) Define the speed error e as the system state variable: where x1 represents the system state error; 3) Define the improved non-singular fast terminal sliding mode surface s as: where p, q, λ2, and λ1 are constants, and p>0, q>0, 0<λ2<2, λ2<λ1, and sgn() is the sign function; 4) Introduce the adaptive power function into the non-singular fast terminal sliding mode exponential reaching law: where k1, k2, and α are positive constants to be designed; When the system state is about to reach the sliding mode surface, i.e., |s| < 1, the variable speed reaching term k1(|x1||s|) 1-αsgn(1-|s|) sgn(s) plays a dominant role, while the exponential reaching term k2|s| 1+α sgn(s) will rapidly approach 0. Obviously, k1(|x1||s|) 1+α and k2|s| 1+α are respectively less than k1|s| 1-α and k2s. As |s| continues to decrease, the system chattering can be effectively reduced on the premise of ensuring convergence.

8. The multi-motor synchronous control method of the TBM main drive system simulation test bench according to claim 5, characterized in that, The specific steps of step S4 include the following: S401. Establish the super-twisting sliding mode disturbance observer model: where s1 and u1 are state variables, and β1 and β2 are sliding mode gain coefficients; S402. Based on the motor's super-local model, establish an extended super-local model of the motor speed loop according to the input and output of the motor's speed loop control: where R(t) is the rate of change of F ω ; S403. Design an extended sliding mode disturbance observer, specifically: Among them, is the real-time estimated value of the motor speed by the observer; is the real-time estimated value of the total unknown part of the system; u smo is the sliding mode function to be designed; l is the sliding mode function u smo gain; Define the observer errors e1 and e2 as follows: When the error of the super-twisting sliding mode disturbance observer is zero and the observer converges asymptotically; Satisfy where ε is an arbitrary positive constant; Based on s1 = e1, discretize the super-twisting sliding mode disturbance observer, and we can get: where T is the sampling period and k is a positive constant; S404. Through the super-twisting sliding mode disturbance observer, real-time observe the part including external disturbances and parameter perturbations in the super-local sliding mode controller, and feedback the observed value e2 to the super-local sliding mode controller to achieve the synchronous control of each motor.

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