Electric excavator and control method, device and medium of electric drive slewing system thereof

Abstract

The electric excavator and the control method, device and medium of the electric drive rotating system thereof relate to the electric excavator rotating control technical field. The method comprises the following steps: performing dynamic modeling on the electric drive rotating system of the excavator to obtain a dynamic model. Based on the dynamic model, system state variables are selected, and a non-singular fast terminal sliding mode speed controller is built with the minimum whole machine rotating speed tracking error and small torque impact as the control target. The structure of the excavator is simplified to establish a space coordinate system and a D-H method coordinate system, and then a mathematical model of the center of gravity of the working device and the moment of inertia changing with the pose is constructed to obtain a total moment of inertia mathematical model of the excavator. In view of the disturbance caused by the load change and the time-varying inertia in the excavator rotating working condition, a Luenberger observer is built, and the observed load value is fed forward to the rotating speed controller to obtain updated control data. The method can solve the problems of unstable rotating speed, large torque pulsation and poor controllability.

Description

Technical Field

[0001] This invention relates to the field of electric excavator slewing control technology, and more specifically, to a control method, device, and medium for an electric excavator and its electric drive slewing system. Background Technology

[0002] Traditional hydraulically driven excavators suffer from significant energy efficiency and maneuverability issues during slewing operations. When using a hydraulic motor to drive the slewing system, the energy transmission path is relatively long, and the overall machine energy efficiency is typically only 15%-30%. Especially during micro-motion operations, a large amount of hydraulic oil needs to flow through the throttle valve, generating heat and causing energy to be dissipated as heat, resulting in serious energy waste. In addition, hydraulic drive systems struggle to achieve smooth and precise start-stop and micro-operations, affecting operational responsiveness and accuracy, and limiting further improvements in overall machine performance.

[0003] In contrast, the electric drive slewing system used in electric excavators has advantages such as a short energy transfer path, high energy efficiency, and zero carbon emissions. It can also efficiently recover braking energy and store it in batteries or supercapacitors, significantly improving energy utilization efficiency. The electric drive system also supports smooth speed regulation and precise micro-operation, which is conducive to the intelligent and digital development of the entire machine.

[0004] However, in actual slewing operations, due to the strong periodicity of the working conditions and the compound actions of multiple actuators, the system still faces frequent load disturbances and time-varying inertia problems, which directly affect the stability of the slewing speed and the quality of operation.

[0005] The aforementioned load disturbances and time-varying inertia issues not only reduce the dynamic response performance of the electric drive slewing system but also lead to increased torque pulsation and system energy consumption, thereby affecting the overall machine's economy and reliability. Therefore, a highly stable control method capable of effectively suppressing external disturbances and inertia variations is urgently needed to improve the overall performance of electric excavators in complex operating environments. Summary of the Invention

[0006] The present invention provides a control method, device and medium for an electric excavator and its electric drive slewing system to improve at least one of the above-mentioned technical problems.

[0007] In a first aspect, the present invention provides a control method for the electric drive slewing system of an electric excavator, which includes the following steps.

[0008] Dynamic modeling was performed on the electric drive slewing system of the excavator to obtain the dynamic model.

[0009] Based on the dynamic model, the system state variables are selected, and a non-singular fast terminal sliding mode speed controller is built with the goal of minimizing the tracking error of the overall machine rotation speed and minimizing the torque impact.

[0010] A simplified excavator structure is established using a spatial coordinate system and a DH method coordinate system. Then, a mathematical model of the center of gravity of the working device and the moment of inertia that varies with the orientation is constructed to obtain a mathematical model of the total moment of inertia of the excavator.

[0011] To address the disturbances caused by load changes and time-varying inertia during the excavator's swing operation, a Luneburger observer was built, and the observed load values ​​were fed forward to the swing speed controller to obtain updated control data.

[0012] In an optional implementation, the dynamic model is: In the formula. This represents the rotational inertia of the entire machine. It is a differential. This refers to the overall rotational angular velocity of the machine. For time. This is the driving torque for the rotation of the entire machine. This is the rotational load torque of the entire machine. is the viscosity coefficient.

[0013] In an optional implementation, the system state variable is: In the formula, This refers to the tracking error of the overall machine's rotational angular velocity. This is the given value for the overall rotational angular velocity. This is the actual value of the overall machine's rotational angular velocity, which can be considered a constant. This represents the rate of change of the tracking error of the overall machine's rotational angular velocity. for The first derivative. for The first derivative.

[0014] In an optional implementation, the state-space equations of the electric-driven rotary system are obtained based on the dynamic model and the system state variables: In the formula. This represents the rotational inertia of the entire machine. This is the rotational load torque of the entire machine. is the viscosity coefficient. This is the driving torque for the rotation of the entire machine. for The first derivative. for The second derivative. for The first derivative. for The first derivative.

[0015] Obtaining the non-singular fast terminal sliding surface: In the formula, It is a sliding surface. This is the first control gain coefficient. This is the second control gain coefficient. This is the third control gain coefficient. It is the first positive odd number. It is the second positive odd number. , and , .

[0016] Differentiate the sliding surface with respect to the nonsingular fast terminal to obtain the first derivative of the sliding surface: .

[0017] Based on the first derivative of the sliding surface, obtain the exponential convergence rate: In the formula, This represents the exponential rate of convergence. The coefficient of the exponential approach term. It is the hyperbolic tangent function. This is the adjustment coefficient for the saturation function. To switch the gain. Among them, , and All are constants greater than 0.

[0018] By simultaneously solving the state-space equations, the first derivative of the sliding surface, and the exponential reaching rate, a non-singular fast terminal sliding mode velocity controller can be obtained.

[0019] In the formula, This is the output of the controller. It is a differential. For time.

[0020] In an alternative implementation, a Lyapunov function is constructed based on Lyapunov stability theory: .

[0021] Differentiating the Lyapunov function yields its first derivative: .

[0022] By combining the first derivative of the sliding surface, the nonsingular fast terminal sliding mode control law, and the first derivative of the Lyapunov function, the system stability condition model is obtained: In the formula, . Let be the natural base. .

[0023] but In the formula For positive definiteness, The value is negative definite, which satisfies the system stability condition and can guarantee the stable operation of the system.

[0024] In an optional implementation, a simplified excavator structure is established using a spatial coordinate system and a DH method coordinate system. Then, a mathematical model of the working device's center of gravity and its moment of inertia as its orientation changes is constructed to obtain the excavator's total moment of inertia mathematical model. Specifically, this includes:

[0025] Simplify the excavator structure, using the swing center of gravity as the coordinate origin. Establish a spatial coordinate system .

[0026] Establish the DH coordinate system with the hinge points of the boom and turntable, the stick and boom, and the bucket and stick as the origins in sequence.

[0027] By multiplying the spatial coordinate transformation matrices, the coordinates of the center of gravity of each working component are obtained, and a mathematical model of the center of gravity of the working device and the moment of inertia that changes with the posture is constructed, thus obtaining the mathematical model of the total moment of inertia of the excavator.

[0028] In an optional implementation, the hinge point between the boom and the turntable is set as... Point, the hinge point between the stick and the boom is Point, the hinge point between the bucket and the stick is Point, the tip of the bucket teeth is point.

[0029] The spatial coordinate transformation matrix is ​​represented as:

[0030] .

[0031] .

[0032] .

[0033] In the formula, , , These represent rotations about the x, y, and z axes, respectively. Spatial coordinate transformation matrix of degrees.

[0034] set up The local coordinates of the point are .

[0035] The coordinates of the point in the spatial coordinate system are:

[0036] .

[0037] In spatial coordinate system The coordinate expression of a point is:

[0038] .

[0039] In the formula, This represents the slewing angle of the boom. Represented as and The length between two points.

[0040] In spatial coordinate system The coordinate expression of a point is:

[0041] .

[0042] In the formula, This refers to the rotation angle of the boom. Represented as and The length between two points.

[0043] In spatial coordinate system The coordinate expression of a point is:

[0044] .

[0045] In the formula, This refers to the rotation angle of the bucket. Represented as and The length between two points.

[0046] The coordinates of the centroid are obtained based on the trigonometric relationship between the centroid and the hinge point. Specifically, the coordinates of the centroid are... In the coordinate expression of a point Replace with ,Will In the coordinate expression of a point Replace with ,Will In the coordinate expression of a point Replace with The coordinates of the center of gravity of the boom, stick, and bucket are obtained respectively.

[0047] .

[0048] .

[0049] .

[0050] In the formula, Here are the coordinates of the boom's center of gravity. These are the coordinates of the pole's center of gravity. These are the coordinates of the bucket's center of gravity. for Point to the center of gravity of the boom The vector length. This is the angle of the boom's center of gravity offset. for Point to the center of gravity of the pole The vector length. The angle of the pole's center of gravity offset. for Point to the center of gravity of the bucket The vector length. This is the angle of the bucket's center of gravity offset.

[0051] The mathematical model for the total moment of inertia is:

[0052] .

[0053] in, This represents the moment of inertia of the entire machine. This indicates that the moment of inertia of the turntable is a fixed value. This represents the moment of inertia of the boom. This represents the moment of inertia of the boom. This represents the moment of inertia of the bucket. This indicates the boom mass. Indicates the mass of the boom. Indicates the mass of the bucket.

[0054] In an alternative implementation, the state-space equation of the Lundberg observer is: In the formula, To find the first derivative of the observed values ​​of the state variable. Let be the state matrix of the system. These are the observed values ​​of the state variables. This is the system's input matrix. Input for the system. This is the error feedback matrix. This is the output. These are the output observations. This is the output matrix. This is a direct matrix.

[0055] In an optional implementation, the moment of inertia of the entire machine is expressed as... Substituting this into the Luneburg observer and setting the characteristic polynomial output of the Luneburg observer to 0 yields the convergent model:

[0056] .

[0057] In the formula, These are the eigenvalues ​​of the matrix. It is an identity matrix. This is the gain matrix of the Luneburg observer. This is the first gain for the Romberg observer. This is the second gain for the Romberg observer. This is the first eigenvalue of the Romberg observer. This is the second eigenvalue of the Romberg observer. . . .

[0058] The gain of the Luneburg observer is:

[0059] .

[0060] The load value observed by the Lunberg observer Feedforward to the non-singular fast terminal sliding mode speed controller to obtain updated control data.

[0061] .

[0062] In the formula, For the updated control data, This represents the load torque observation value output by the Luneburger observer.

[0063] Secondly, the present invention provides a control device for the electric drive slewing system of an electric excavator, which includes the following modules.

[0064] The model building module is used to perform dynamic modeling on the electric drive slewing system of an excavator and obtain the dynamic model.

[0065] The controller module is used to select system state variables based on the dynamic model and to build a non-singular fast terminal sliding mode speed controller with the control objective of minimizing the tracking error of the overall machine rotation speed and minimizing torque impact.

[0066] The moment of inertia module is used to simplify the excavator structure by establishing a spatial coordinate system and a DH method coordinate system. Then, it constructs a mathematical model of the center of gravity of the working device and the moment of inertia that changes with the posture, and obtains the mathematical model of the total moment of inertia of the excavator.

[0067] The update module is used to build a Luneburger observer to address disturbances caused by load changes and time-varying inertia during the excavator's swing operation, and feeds the observed load values ​​forward to the swing speed controller to obtain updated control data.

[0068] Thirdly, the present invention provides an electric excavator, which includes a processor, a memory, and a computer program stored in the memory. The computer program can be executed by the processor to implement a control method for the electric drive slewing system of an electric excavator as described in any paragraph of the first aspect.

[0069] Fourthly, the present invention provides a computer-readable storage medium comprising a stored computer program, wherein, when the computer program is executed, it controls the device containing the computer-readable storage medium to perform a control method for an electric drive slewing system of an electric excavator as described in any paragraph of the first aspect.

[0070] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0071] This invention, through the design of a sliding mode speed controller with disturbance compensation, can solve the problems of unstable slewing speed, large torque pulsation, and poor maneuverability caused by load disturbances and time-varying inertia in electric-driven excavators. It also improves the energy efficiency of the electric drive system.

[0072] This invention models the electric drive slewing system of an excavator and builds a non-singular fast terminal sliding mode speed controller based on the system's state-space equations. Simultaneously, it obtains a mathematical model of the machine's rotational inertia using the DH method and spatial coordinate transformation matrix. This mathematical model is then combined with a Luneburger observer to improve the accuracy of the observed values, which are then fed forward to the sliding mode speed controller. This process can resist the influence of load disturbances and time-varying inertia during slewing, resulting in stable slewing speed without overshoot. This improves maneuverability while reducing energy consumption. Attached Figure Description

[0073] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the specific embodiments of the present invention will be briefly introduced below. It should be understood that the following drawings only show some specific embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0074] Figure 1 This is a flowchart illustrating the control method of the electric drive slewing system of an electric excavator.

[0075] Figure 2 It is a simplified model of the whole machine in the DH coordinate system.

[0076] Figure 3 This is a simulation comparison of the overall vehicle rotation speed of the electric drive slewing system of an electric excavator under traditional excavation slewing conditions.

[0077] Figure 4 The results are simulations of the tracking error of the electric drive slewing system of an electric excavator under traditional excavation slewing conditions.

[0078] Figure 5 This is a simulation result of the effective energy output of the rotary motor of an electric excavator's electric drive rotary system under traditional excavation conditions. Detailed Implementation

[0079] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0080] Example 1, please refer to Figures 1 to 5 The first embodiment of the present invention provides a control method for the electric drive slewing system of an electric excavator, which can be executed by a control device for the electric drive slewing system of the electric excavator (hereinafter referred to as: control device). In particular, it is executed by one or more processors in the control device to implement steps S1 to S4.

[0081] S1. Perform dynamic modeling on the electric drive slewing system of the excavator to obtain the dynamic model.

[0082] Preferably, the dynamic model of the electric drive slewing system of the electric excavator is as follows:

[0083] .

[0084] In the formula. This represents the rotational inertia of the entire machine. It is a differential. This refers to the overall rotational angular velocity of the machine. For time. This is the driving torque for the rotation of the entire machine. This is the rotational load torque of the entire machine. is the viscosity coefficient.

[0085] S2. Based on the dynamic model, select the system state variables, and take the minimum tracking error of the whole machine rotation speed and the small torque impact as the control objective to build a non-singular fast terminal sliding mode speed controller.

[0086] Based on the above embodiments, in an optional embodiment of the present invention, step S2 includes steps S21 to S26.

[0087] S21. Based on the dynamic model, select the system state variables. The system state variables are:

[0088] .

[0089] In the formula, This refers to the tracking error of the overall machine's rotational angular velocity. This is the given value for the overall rotational angular velocity. This is the actual value of the overall machine's rotational angular velocity, which can be considered a constant. This represents the rate of change of the tracking error of the overall machine's rotational angular velocity. for The first derivative. for The first derivative.

[0090] S22. Based on the dynamic model and the system state variables, obtain the state-space equation of the electric drive rotary system:

[0091] .

[0092] In the formula. This represents the rotational inertia of the entire machine. This is the rotational load torque of the entire machine. is the viscosity coefficient. This is the driving torque for the rotation of the entire machine. for The first derivative. for The second derivative. for The first derivative. for The first derivative.

[0093] S23. Obtain the non-singular fast terminal sliding surface:

[0094] .

[0095] In the formula, It is a non-singular fast terminal sliding surface. This is the first control gain coefficient. This is the second control gain coefficient. This is the third control gain coefficient. It is the first positive odd number. It is the second positive odd number. Where 1 < <2, and , .

[0096] S24. Take the derivative with respect to the non-singular fast terminal sliding surface to obtain the first derivative of the sliding surface:

[0097] .

[0098] S25. Obtain the exponential convergence rate based on the first derivative of the sliding surface:

[0099] .

[0100] In the formula, This represents the exponential rate of convergence. The coefficient of the exponential approach term. It is the hyperbolic tangent function. This is the adjustment coefficient for the saturation function. To switch the gain. Among them, , and All are constants greater than 0.

[0101] S26. By simultaneously solving the state-space equations, the first derivative of the sliding surface, and the exponential reaching rate, obtain the non-singular fast terminal sliding mode velocity controller:

[0102] .

[0103] In the formula, This is the output of the controller. It is a differential. For time.

[0104] Based on the above embodiments, in an optional embodiment of the present invention, step S2 further includes steps S27 to S29.

[0105] S27. Construct the Lyapunov function based on Lyapunov stability theory:

[0106] .

[0107] S28. Take the derivative of the Lyapunov function to obtain its first derivative:

[0108] .

[0109] S29. By combining the first derivative of the sliding surface, the non-singular fast terminal sliding mode control law, and the first derivative of the Lyapunov function, obtain the system stability condition model:

[0110] .

[0111] In the formula, . It is the natural base. , , ,and and If it is a positive odd number, then .

[0112] but In the formula For positive definiteness, If the value is negative, the system stability condition is met, which can guarantee the stable operation of the system.

[0113] S3. Simplify the excavator structure, establish a spatial coordinate system and a DH method coordinate system, and then construct a mathematical model of the center of gravity of the working device and the moment of inertia that changes with the posture, and obtain the mathematical model of the total moment of inertia of the excavator.

[0114] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 2 The figure shows a simplified model of the entire machine in the DH coordinate system. Preferably, step S3 specifically includes:

[0115] S31. Simplify the excavator structure, using the slewing center of gravity as the coordinate origin. Establish a spatial coordinate system .

[0116] S32. Establish the DH coordinate system with the hinge points of the boom and turntable, the boom and stick, and the bucket and stick as the origins in sequence.

[0117] S33. By multiplying the spatial coordinate transformation matrices, the coordinates of the center of gravity of each working component are obtained, and a mathematical model of the center of gravity of the working device and the moment of inertia that changes with the posture is constructed to obtain the mathematical model of the total moment of inertia of the excavator.

[0118] Set the hinge point between the boom and the turntable as Point, the hinge point between the stick and the boom is Point, the hinge point between the bucket and the stick is Point, the tip of the bucket teeth is point.

[0119] The spatial coordinate transformation matrix is:

[0120] .

[0121] .

[0122] .

[0123] In the formula, , , These represent rotations about the x, y, and z axes, respectively. Spatial coordinate transformation matrix of degrees.

[0124] Setting the hinge point between the boom and the turntable The local coordinates are .

[0125] In spatial coordinate system The coordinate expression of a point is:

[0126] .

[0127] In spatial coordinate system The coordinate expression of a point is:

[0128] .

[0129] In the formula, This represents the slewing angle of the boom. Represented as and The length between two points.

[0130] In spatial coordinate system The coordinate expression of a point is:

[0131] .

[0132] In the formula, This refers to the rotation angle of the boom. Represented as and The length between two points.

[0133] In spatial coordinate system The coordinate expression of a point is:

[0134] .

[0135] In the formula, This refers to the rotation angle of the bucket. Represented as and The length between two points.

[0136] The coordinates of the centroid are obtained based on the trigonometric relationship between the centroid and the hinge point. Specifically, the coordinates of the centroid are... In the coordinate expression of a point Replace with ,Will In the coordinate expression of a point Replace with ,Will In the coordinate expression of a point Replace with The coordinates of the center of gravity of the boom, stick, and bucket are obtained respectively.

[0137] .

[0138] .

[0139] .

[0140] In the formula, Here are the coordinates of the boom's center of gravity. These are the coordinates of the pole's center of gravity. These are the coordinates of the bucket's center of gravity. for Point to the center of gravity of the boom The vector length. This is the angle of the boom's center of gravity offset. for Point to the center of gravity of the pole The vector length. The angle of the pole's center of gravity offset. for Point to the center of gravity of the bucket The vector length. This is the angle of the bucket's center of gravity offset.

[0141] The mathematical model for the total moment of inertia is:

[0142] .

[0143] In the formula, This represents the rotational inertia of the entire machine. The moment of inertia of the turntable is a fixed value. Let be the moment of inertia of the boom. Let be the moment of inertia of the boom. Let be the moment of inertia of the bucket. The mass of the boom. This refers to the mass of the boom. For bucket quality. for Point to the center of gravity of the boom The vector length. for Point to the center of gravity of the pole The vector length. for Point to the center of gravity of the bucket The vector length.

[0144] S4. To address the disturbances caused by load changes and time-varying inertia during the excavator's slewing operation, a Luneburger observer is built, and the observed load values ​​are fed forward to the slewing speed controller to obtain updated control data.

[0145] Preferably, the state-space equation of the Luneburg observer is:

[0146] .

[0147] In the formula, To find the first derivative of the observed values ​​of the state variable. Let be the state matrix of the system. These are the observed values ​​of the state variables. This is the system's input matrix. Input for the system. This is the error feedback matrix. This is the output. These are the output observations. This is the output matrix. This is a direct matrix.

[0148] The moment of inertia of the entire machine is expressed as... Substituting this into the Luneburg observer and setting the characteristic polynomial output of the Luneburg observer to 0 yields the convergent model:

[0149] .

[0150] In the formula, These are the eigenvalues ​​of the matrix. It is an identity matrix. This is the gain matrix of the Luneburg observer. This is the first gain for the Romberg observer. This is the second gain for the Romberg observer. This is the first eigenvalue of the Romberg observer. This is the second eigenvalue of the Romberg observer. . . .

[0151] The gain of the Luneburg observer is:

[0152] .

[0153] The load values ​​observed by the Luneburger observer are fed forward to the non-singular fast terminal sliding mode speed controller to obtain updated control data (i.e., output).

[0154] .

[0155] In the formula, For the updated control data, This represents the load torque observation value output by the Luneburger observer.

[0156] In a specific embodiment provided by the present invention, the main parameters of the slewing system are shown in Table 1, and the main parameters of the controller are shown in Table 2.

[0157] Table 1 Main parameters of the slewing system

[0158]

[0159] Table 2 Main Parameters of the Controller

[0160]

[0161] The simulation results are as follows: Figure 3 and Figure 4As shown, the non-singular fast terminal sliding mode speed controller (NFTSMC+DOB controller) with disturbance compensation, built based on the control method of the electric drive slewing system of the electric excavator of this invention, can stably follow the target speed curve under digging slewing conditions. Its response speed is approximately 70ms faster than the PID controller. The maximum speed tracking error of the PID controller is 0.6 rpm, and the average tracking error is 0.31 rpm, while the maximum speed tracking error of the NFTSMC+DOB controller is 0.51 rpm, and the average tracking error is 0.23 rpm. Figure 3 In this context, PID represents a PID controller, and NFTSMC+DOB represents an NFTSMC+DOB controller.

[0162] The NFTSMC+DOB controller effectively reduces the impact of load disturbances and rotational inertia on the rotation speed during excavation rotation, thus improving maneuverability. For example... Figure 5 As shown, under a single cycle of excavation rotation, the rotary motor ultimately consumes 17.8 kJ of energy, of which the total energy consumption is 98.4 kJ and the total energy feedback is 80.6 kJ, with an energy saving rate of 63.6%.

[0163] This invention, through the design of a sliding mode speed controller with disturbance compensation, can solve the problems of unstable slewing speed, large torque pulsation, and poor maneuverability caused by load disturbances and time-varying inertia in electric-driven excavators. It also improves the energy efficiency of the electric drive system.

[0164] This invention models the electric drive slewing system of an excavator and builds a non-singular fast terminal sliding mode speed controller based on the system's state-space equations. Simultaneously, it obtains a mathematical model of the machine's rotational inertia using the DH method and spatial coordinate transformation matrix. This mathematical model is then combined with a Luneburger observer to improve the accuracy of the observed values, which are then fed forward to the sliding mode speed controller. This process can resist the influence of load disturbances and time-varying inertia during slewing, resulting in stable slewing speed without overshoot. This improves maneuverability while reducing energy consumption.

[0165] Example 2: The present invention provides a control device for the electric drive slewing system of an electric excavator, which includes the following modules.

[0166] The model building module is used to perform dynamic modeling on the electric drive slewing system of an excavator and obtain the dynamic model.

[0167] The controller module is used to select system state variables based on the dynamic model and to build a non-singular fast terminal sliding mode speed controller with the control objective of minimizing the tracking error of the overall machine rotation speed and minimizing torque impact.

[0168] The moment of inertia module is used to simplify the excavator structure by establishing a spatial coordinate system and a DH method coordinate system. Then, it constructs a mathematical model of the center of gravity of the working device and the moment of inertia that changes with the posture, and obtains the mathematical model of the total moment of inertia of the excavator.

[0169] The update module is used to build a Luneburger observer to address disturbances caused by load changes and time-varying inertia during the excavator's swing operation, and feeds the observed load values ​​forward to the swing speed controller to obtain updated control data.

[0170] Example 3: This invention provides an electric excavator, which includes a processor, a memory, and a computer program stored in the memory. The computer program can be executed by the processor to implement a control method for the electric drive slewing system of an electric excavator as described in any paragraph of Example 1.

[0171] Example 4: The present invention provides a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to execute a control method for the electric drive slewing system of an electric excavator as described in any paragraph of Example 1.

[0172] It is understood that the control device may be the control device on an electric excavator, or a remote server or other electronic device with computing power.

[0173] Obviously, the embodiments described above are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0174] In the several embodiments provided in this invention, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus and method embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0175] In addition, the functional modules in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0176] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, electronic device, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks. It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0177] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention are also intended to include the plural forms unless the context clearly indicates otherwise.

[0178] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0179] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0180] The terms "first" and "second" used in the embodiments are merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first" and "second" can be interchanged in a specific order or sequence where permitted. It should be understood that the objects distinguished by "first" and "second" can be interchanged where appropriate so that the embodiments described herein can be implemented in an order other than those illustrated or described herein.

[0181] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method of an electric drive slewing system of an electric shovel, characterized by, Comprise: The dynamics model of the electric drive slewing system of the excavator is established to obtain a dynamics model; Based on the dynamics model, system state variables are selected, and a non-singular fast terminal sliding mode speed controller is built with the minimum slewing speed tracking error of the whole machine and small torque impact as the control target; The spatial coordinate system and the D-H coordinate system are established by simplifying the structure of the excavator, and then the mathematical model of the center of gravity of the working device and the moment of inertia changing with the pose is constructed to obtain the total moment of inertia mathematical model of the excavator, which specifically includes: The D-H coordinate system is established with the hinge joint point of the boom and the slewing ring, the hinge joint point of the arm and the boom, and the hinge joint point of the bucket and the arm as the origin in turn; The system state variables are: ; wherein, is an integral machine rotation angle velocity tracking error; is an integral machine rotation angle velocity given value; is an integral machine rotation angle velocity actual value, which can be regarded as a constant; is a rate of change of the integral machine rotation angle velocity tracking error; is a first derivative of ; and is a first derivative of ; According to the dynamic model and the system state variable, a state space equation of the electric drive slewing system is obtained: ; wherein, is the whole machine rotational inertia; is the whole machine slewing load torque; is the viscous coefficient; is the whole machine slewing driving torque; is the first derivative of ; is the second derivative of ; is the first derivative of ; is the first derivative of ; obtaining a non-singular fast terminal sliding mode surface: ; where, is a sliding mode surface; is a first control gain coefficient; is a second control gain coefficient; is a third control gain coefficient; is a first positive odd integer; is a second positive odd integer; where, , and , ; The derivative of the non-singular fast terminal sliding mode surface is obtained, and the first-order derivative of the sliding mode surface is obtained: ; According to the first derivative of the sliding surface, the exponential approach rate is obtained: wherein, is the exponential approach rate; is the exponential approach term coefficient; is the hyperbolic tangent function; is the saturation function adjustment coefficient; is the switching gain; wherein, , and are constants greater than 0; The center of gravity coordinates of each working component are obtained through the multiplication of the spatial coordinate transformation matrix to construct the mathematical model of the center of gravity of the working device and the moment of inertia changing with the pose, and obtain the total moment of inertia mathematical model of the excavator. ; where, is an output quantity of the controller; is a derivative; is time.

2. The control method of the electric drive swing system of the electric excavator according to claim 1, characterized by, The dynamic model is: ; in which is the whole machine rotational inertia; is the differential; is the whole machine rotational angular velocity; is the time; is the whole machine rotational driving torque; is the whole machine rotational load torque; is the viscous coefficient.

3. The control method of the electric drive swing system of the electrically driven excavator according to claim 1, characterized by, According to Lyapunov stability theory, a Lyapunov function is constructed: ; Derive the Lyapunov function to obtain the first derivative of the Lyapunov function: ; The first derivative of the sliding surface, the nonsingular fast terminal sliding mode control rate and the first derivative of the Lyapunov function are combined to obtain a system stability condition model: ; wherein, ; is the natural base; then ; Then , where is positive definite, is negative definite, satisfying the system stability condition, which can ensure the stable operation of the system.

4. The control method of the electric drive swing system of the electric excavator according to claim 1, characterized by, The spatial coordinate transformation matrix is represented as: Simplify excavator structure to take rotation gravity center as coordinate origin , establish space coordinate system ; The total moment of inertia mathematical model is: The gain of the Luenberger observer is:

5. The control method of the electric drive slewing system of the electrically driven excavator according to claim 4, characterized in that, The set point of the boom and the turntable hinge is The set point of the boom and the turntable hinge is The set point of the boom and the turntable hinge is The set point of the boom and the turntable hinge is The set point of the boom and the turntable hinge is A control method of an electric drive slewing system of an electric excavator is suitable for performing any one of claims 1-6; ； ； ； wherein , , respectively represent spatial coordinate transformation matrices that rotate degrees about the x, y, z axes Set The local coordinates of the point are ; The coordinates of the point in the spatial coordinate system are: ； In the spatial coordinate system The coordinate expression of the point is: ； In the formula, is the rotation angle of the boom; is represented as and the length between two points; In the spatial coordinate system The coordinate expression of the point is: ； In the formula, is the swing angle of the arm; is represented as and the length between two points; In the spatial coordinate system The coordinate expression of the point is: ； In the formula, is the slewing angle of the bucket; is represented as and the length between two points; According to the trigonometric function relationship between the barycenter and the hinge point, the barycenter coordinates are obtained; wherein, the coordinate expression of the point is replaced by , the coordinate expression of the point is replaced by , the coordinate expression of the point is replaced by , the coordinate expression of the point is replaced by , and the barycenter coordinates of the boom, the stick and the bucket are obtained respectively. ； ； ； wherein is the boom center of gravity coordinate; is the stick center of gravity coordinate; is the bucket center of gravity coordinate; is the vector length from the point to the boom center of gravity is the boom center of gravity offset angle; is the vector length from the point to the stick center of gravity is the stick center of gravity offset angle; is the vector length from the point to the bucket center of gravity is the bucket center of gravity offset angle; is the vector length from the point to the bucket center of gravity is the bucket center of gravity offset angle; The control device comprises: ； wherein, represents the whole machine moment of inertia; represents the turntable moment of inertia as a fixed value; represents the boom moment of inertia; represents the arm moment of inertia; represents the bucket moment of inertia; represents the boom mass; represents the arm mass; represents the bucket mass.

6. The control method of the electric drive swing system of the electrically driven excavator according to claim 1, characterized by, The state space equation of the Luenberger observer is: where, is the first derivative of the observed value of the state variable; is the state matrix of the system; is the observed value of the state variable; is the input matrix of the system; is the system input; is the error feedback matrix; is the output; is the observed value of the output; is the output matrix; is the direct matrix; The whole machine rotational inertia is expressed as , into the Luenberger observer, and the characteristic polynomial output of the Luenberger observer is made to be 0 to obtain a convergence model: ； wherein is a matrix eigenvalue; is an identity matrix; is a Luenberger observer gain matrix; is a first gain of the Luenberger observer; is a second gain of the Luenberger observer; is a first eigenvalue of the Luenberger observer; is a second eigenvalue of the Luenberger observer; ; ; ; A model construction module for establishing a dynamics model of the electric drive slewing system of the excavator to obtain a dynamics model; ； Load value observed by a Luenberger observer The updated control data is obtained by feeding forward to a non-singular fast terminal sliding mode speed controller. ； In the formula, is the updated control data, is the load torque observation value output by the Luenberger observer.

7. A control device of an electric drive slewing system of an electric shovel, characterized by, A controller module for selecting system state variables based on the dynamics model, and building a non-singular fast terminal sliding mode speed controller with the minimum slewing speed tracking error of the whole machine and small torque impact as the control target; A moment of inertia module for establishing a spatial coordinate system and a D-H coordinate system by simplifying the structure of the excavator, and then constructing a mathematical model of the center of gravity of the working device and the moment of inertia changing with the pose to obtain a total moment of inertia mathematical model of the excavator; An update module for building a Luenberger observer for the disturbance caused by the load change and time-varying inertia in the slewing working condition of the excavator, and feeding the observed load value to the slewing speed controller to obtain updated control data. The computer readable storage medium comprises a stored computer program, wherein the computer readable storage medium controls the device where the computer readable storage medium is located to execute the control method of the electric drive slewing system of the electric excavator according to any one of claims 1-6 when the computer program runs. ​ ​ 8. An electrically powered excavator, characterised in that ​ 9. A computer-readable storage medium, characterized in that, ​

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