A discrete-time optimal control method with adjustable speed and small overshoot

Abstract

The application discloses a kind of discrete time optimal control methods of adjustable speed small overshoot, comprising: step 1, input desired position and desired speed, determine state variable;Step 2, according to the phase flow diagram of improved discrete time optimal controller, determine phase trajectory, according to phase trajectory, obtain corresponding different control quantity at different phase points, and control quantity is desired acceleration;Step 3, desired acceleration and feedback speed are input into extended state observer, and current control quantity is calculated;Step 4, current control quantity is input into current loop, and current loop Q axis and D axis desired voltage are calculated respectively;Step 5, Q axis and D axis desired voltage are input into SVPWM control module, and three-phase control duty cycle is calculated, input into drive board and drive shaft system rotation.The application is aimed at the characteristics of time and space requirements symmetry in the process of modulation motion of inertial navigation equipment, and a kind of adjustable speed, small overshoot, response speed fast control method is designed to improve the navigation accuracy of inertial navigation system.

Description

Technical Field

[0001] This invention relates to the field of inertial navigation, and more particularly to a discrete-time optimal control method with adjustable speed and small overshoot. Background Technology

[0002] Shipborne inertial navigation systems (INS) are autonomous position calculation systems that use inertial devices (gyroscopes, accelerometers), angle sensors, reference directions, and initial positions to determine a ship's heading, position, and velocity. Due to the zero-drift characteristic of gyroscopes, the accuracy of INS systems decreases. To address this issue, modulated INS was proposed. Symmetrical motion eliminates some of the accumulated error. Therefore, the temporal and spatial symmetry of the modulated motion becomes important, as velocity overshoot has a significant impact on the system.

[0003] Discrete-time optimal control is an important method for inertial navigation system (INS) control, characterized by high control bandwidth and stability. However, commonly used discrete-time optimal control methods often suffer from large position overshoot and unlimited speed, which is detrimental to INS. To apply discrete-time optimal control methods while avoiding excessive overshoot and also providing speed regulation capabilities, a discrete-time optimal control method with adjustable speed and small overshoot was designed. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide an adjustable speed, small overshoot, discrete-time optimal control method to address the deficiencies in the prior art. In view of the symmetrical requirements of time and space during the modulation motion of inertial navigation equipment, this invention designs an adjustable speed, small overshoot, and fast response control method to improve the navigation accuracy of the inertial navigation system.

[0005] The technical solution adopted by this invention to solve its technical problem is: This invention provides a discrete-time optimal control method with adjustable speed and small overshoot. During the modulation motion of an inertial navigation device, a control method is constructed that includes an improved discrete-time optimal controller, an extended state observer, a current loop, and an SVPWM control module. The method includes: Step 1: Input the desired position and desired velocity to determine the state variables; Step 2: Determine the phase trajectory based on the phase flow diagram of the improved discrete-time optimal controller. Based on the phase trajectory, obtain the corresponding different control quantities at different phase points. The control quantities are the desired accelerations. Step 3: Input the desired acceleration and feedback velocity into the extended state observer to calculate the current control quantity; Step 4: Input the current control quantity into the current loop and calculate the desired voltages on the Q-axis and D-axis of the current loop respectively; Step 5: Input the desired voltages of the Q-axis and D-axis into the SVPWM control module, calculate the three-phase control duty cycle, and input it into the drive board to drive the shaft system to rotate.

[0006] Further, the method of step 1 of the present invention includes: Input the desired location, and calculate the difference between the current actual location and the desired location to obtain the location status. x The desired speed is always 0; the current actual speed is the speed state. v Two state variables are obtained. x , v .

[0007] Further, the method of step 2 of the present invention includes: a. In the phase flow diagram of the improved discrete-time optimal controller, the region where the origin can be reached in two steps is the region where the control quantity can reach the origin in two steps and is within the allowable range. The control quantity in this region is taken as follows based on the actual phase point:

[0008] b. The switching curve adjustment area is the region where the switching curve can be reached in one step of control, and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position:

[0009] c. The speed curve adjustment area is the region where the maximum speed limit can be reached with one-step control and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position:

[0010] d. Other regions refer to regions other than those in step ac. The control values ​​for these regions are taken based on the actual phase point locations:

[0011] in, x Express posture, v Indicates speed, h Indicates the step size. v m Indicates the maximum amplitude limit speed. u m This represents the maximum control quantity, i.e., acceleration.

[0012] Furthermore, the method in step 4 of the present invention includes: Input the current control quantity into the Q-axis of the current loop and use the vector control method. The desired current on the D-axis is 0. The current loop can be controlled by PID. Calculate the desired voltages on the Q-axis and D-axis respectively.

[0013] This invention provides a discrete-time optimal control system with adjustable speed and small overshoot, comprising: An improved discrete-time optimal controller is used to determine the phase trajectory based on the phase flow diagram. Based on the phase trajectory, different control quantities are obtained at different phase points, and the control quantities are the desired accelerations. An extended state observer is used to input the desired acceleration and feedback velocity into the extended state observer, compensate for the deviation from the desired acceleration, track the acceleration, and calculate the current control quantity. The current loop is used to input current control quantities into the current loop and calculate the desired voltages on the Q-axis and D-axis of the current loop, respectively. The SVPWM control module is used to input the desired voltages of the Q-axis and D-axis, calculate the three-phase control duty cycle, and input it to the drive board to drive the shaft system to rotate.

[0014] Furthermore, the implementation method of the improved discrete-time optimal controller of the present invention includes: a. In the phase flow diagram of the improved discrete-time optimal controller, the region where the origin can be reached in two steps is the region where the control quantity can reach the origin in two steps and is within the allowable range. The control quantity in this region is taken as follows based on the actual phase point:

[0015] b. The switching curve adjustment area is the region where the switching curve can be reached in one step of control, and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position:

[0016] c. The speed curve adjustment area is the region where the maximum speed limit can be reached with one-step control and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position:

[0017] d. Other regions refer to regions other than those in step ac. The control values ​​for these regions are taken based on the actual phase point locations:

[0018] in, x Express posture, v Indicates speed, h Indicates the step size. v m Indicates the maximum amplitude limit speed. u m This represents the maximum control quantity, i.e., acceleration.

[0019] The beneficial effects of this invention are: 1. Reduced control overshoot, making it more suitable for inertial navigation modulation, thus improving inertial navigation accuracy; 2. It can limit the speed, thus enabling speed tracking control; 3. It has good static stability and fast dynamic response control effect. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a block diagram of the shipborne inertial navigation equipment control system according to an embodiment of the present invention; Figure 2 This is a phase flow diagram of the MDTOC control method according to an embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] This invention addresses the symmetrical requirements of time and space during the modulation motion of inertial navigation systems (INS), designing a control method with adjustable speed, small overshoot, and fast response to improve navigation accuracy. The method includes: 1) An improved discrete-time optimal controller; 2) Extended State Observer; 3) Current loop; 4) Space Vector Pulse Width Modulation (SVPWM) control module.

[0023] In this embodiment of the invention, an improved discrete-time optimal controller is designed, taking the control time of the discrete system as the objective and considering the speed limit requirements or speed tracking requirements in actual systems. The improved discrete-time optimal controller uses position error and speed error as inputs to calculate the desired acceleration. An extended state observer compensates for deviations from the desired acceleration based on the desired input acceleration and the feedback speed, thereby achieving the goal of tracking the acceleration command. The control quantity corrected by the extended state observer becomes a current command. When vector control is used, the current command is directly assigned to the Q-axis, and the D-axis current is set to 0. After coordinate transformation and SVPWM transformation, the three-phase control duty cycle is obtained and output to the driver to drive the shaft system motion. The current, speed, and position are then fed back to various parts of the control system through a sampling circuit to form a closed-loop control.

[0024] In a specific embodiment of the present invention, it specifically includes an improved discrete-time optimal control (MDTOC), an extended state observer (ESO), a current loop, and an SVPWM module. The control block diagram is shown below. Figure 1 As shown. x Express posture, v Indicates speed, h Indicates the step size. v m Indicates the maximum amplitude limit speed. u m This represents the maximum control quantity (actually acceleration). The implementation method is as follows: 1) Determine the state variables. Input the desired position, and subtract the desired position from the current actual position to obtain the position state. x The desired speed is always 0; the current actual speed is the speed state. v Two state variables are obtained ( x , v ).

[0025] 2) Determine the phase trajectory. The phase trajectory is determined based on the phase flow diagram, such as... Figure 2 As shown. Based on the phase trajectory, different control quantities correspond to different phase points. The different control quantities corresponding to different regions are: The region where the origin can be reached in two steps (referring to the region where two-step control can reach the origin and the control quantity is within the allowable range). The control quantity in this region is determined based on the actual phase point, and the control quantity is set to [value missing].

[0026] The switching curve adjustment region (refers to the area where a single-step control can reach the switching curve, and the control quantity is within the allowable range). The control quantity corresponding to this region is taken as [value missing] based on the actual phase point location.

[0027] The speed curve adjustment region (refers to the area where one-step control can reach the maximum speed limit and the control quantity is within the allowable range). The control quantity corresponding to this region is taken as [value missing] based on the actual phase point position.

[0028] Other areas (referring to areas other than those mentioned above). The control value for this area is taken as follows, based on the actual phase point location.

[0029] 3) Input the control quantity (actually the desired acceleration) and feedback velocity into the large expansion state observer to calculate the current control quantity.

[0030] 4) Input the current control quantity into the Q-axis of the current loop, using a vector control method, with the desired current on the D-axis being 0. The current loop can be controlled using PID control, and the desired voltages on the Q-axis and D-axis can be calculated separately.

[0031] 5) Input the Q-axis and D-axis voltages into the SVPWM module, calculate the three-phase control duty cycle, and input it into the drive board to drive the shaft system to rotate.

[0032] The method of this invention reduces control overshoot, making it more suitable for inertial navigation modulation and improving inertial navigation accuracy; it can limit speed, thus enabling speed tracking control; and it has good static stability and fast dynamic response.

[0033] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0034] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A discrete-time optimal control method with adjustable speed and small overshoot, characterized in that, During the modulation motion of the inertial navigation device, a control method was constructed that includes an improved discrete-time optimal controller, an extended state observer, a current loop, and an SVPWM control module; this method includes: Step 1: Input the desired position and desired velocity to determine the state variables; Step 2: Determine the phase trajectory based on the phase flow diagram of the improved discrete-time optimal controller. Based on the phase trajectory, obtain the corresponding different control quantities at different phase points. The control quantities are the desired accelerations. Step 3: Input the desired acceleration and feedback velocity into the extended state observer to calculate the current control quantity; Step 4: Input the current control quantity into the current loop and calculate the desired voltages on the Q-axis and D-axis of the current loop respectively; Step 5: Input the desired voltages of the Q-axis and D-axis into the SVPWM control module, calculate the three-phase control duty cycle, and input it into the drive board to drive the shaft system to rotate; The method in step 2 includes: a. In the phase flow diagram of the improved discrete-time optimal controller, the region where the origin can be reached in two steps is the region where the control quantity can reach the origin in two steps and is within the allowable range. The control quantity in this region is taken as follows based on the actual phase point: b. The switching curve adjustment area is the region where the switching curve can be reached in one step of control, and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position: c. The speed curve adjustment area is the region where the maximum speed limit can be reached with one-step control and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position: d. Other regions refer to regions other than those in step ac. The control values ​​for these regions are taken based on the actual phase point locations: in, x Express posture, v Indicates speed, h Indicates the step size. v m Indicates the maximum amplitude limit speed. u m This represents the maximum control quantity, i.e., acceleration.

2. The discrete-time optimal control method with small adjustable speed overshoot according to claim 1, characterized in that, The method in step 1 includes: Input the desired location, and calculate the difference between the current actual location and the desired location to obtain the location status. x The desired speed is always 0; the current actual speed is the speed state. v Two state variables are obtained. x , v .

3. The discrete-time optimal control method with small adjustable speed overshoot according to claim 1, characterized in that, The method in step 4 includes: Input the current control quantity into the Q-axis of the current loop and use the vector control method. The desired current on the D-axis is 0. The current loop can be controlled by PID. Calculate the desired voltages on the Q-axis and D-axis respectively.

4. A discrete-time optimal control system with adjustable speed and small overshoot, characterized in that, include: An improved discrete-time optimal controller is used to determine the phase trajectory based on the phase flow diagram. Based on the phase trajectory, different control quantities are obtained at different phase points, and the control quantities are the desired accelerations. An extended state observer is used to input the desired acceleration and feedback velocity into the extended state observer, compensate for the deviation from the desired acceleration, track the acceleration, and calculate the current control quantity. The current loop is used to input current control quantities into the current loop and calculate the desired voltages on the Q-axis and D-axis of the current loop, respectively. The SVPWM control module is used to input the desired voltages of the Q-axis and D-axis, calculate the three-phase control duty cycle, and input it to the drive board to drive the shaft system to rotate. The implementation method of the improved discrete-time optimal controller includes: a. In the phase flow diagram of the improved discrete-time optimal controller, the region where the origin can be reached in two steps is the region where the control quantity can reach the origin in two steps and is within the allowable range. The control quantity in this region is taken as follows based on the actual phase point: b. The switching curve adjustment area is the region where the switching curve can be reached in one step of control, and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position: c. The speed curve adjustment area is the region where the maximum speed limit can be reached with one-step control and the control quantity is within the allowable range. The control quantity corresponding to this region is taken as follows, based on the actual phase point position: d. Other regions refer to regions other than those in step ac. The control values ​​for these regions are taken based on the actual phase point locations: in, x Express posture, v Indicates speed, h Indicates the step size. v m Indicates the maximum amplitude limit speed. u m This represents the maximum control quantity, i.e., acceleration.

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