Optimized Driving Control and Positioning Method for a Backlash-Eliminating Locking Mechanism of a Spacecraft

Abstract

The present invention provides an optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft, which includes two closed-loop modes. The first closed-loop mode is used for the backlash elimination and locking mechanism to operate to the locking working position; the second closed-loop mode is used for the backlash elimination and locking mechanism to operate from the locking working position to the floating working position. The present invention can be used in 5 working conditions, four of which are the switching between working positions, and the other working condition is the "zero finding" positioning after the computer resets and loses the number of steps. At the same time, the two closed-loop modes designed by the present invention both include precise positioning strategies, realizing the optimized drive control and positioning of the backlash elimination and locking mechanism, and overcoming the influence caused by the motor losing steps due to the blocked stroke when the backlash elimination and locking mechanism runs to the contact working position.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace, and relates to an optimized drive control and positioning method for a backlash elimination and locking mechanism for a space spacecraft. Background Art

[0002] For a complex spacecraft, when there are two working conditions of contact locking and non-contact suspension between two platforms, a backlash elimination and locking mechanism is required to control the distance between the two platforms. Hall sensors are installed at the positions corresponding to the two working modes of contact locking and non-contact suspension, which can be used for positioning the backlash elimination and locking mechanism.

[0003] When the backlash elimination and locking mechanism switches between the two working modes, the drive circuit needs to control the mechanism to run to the precise position. Only when the backlash elimination and locking mechanism runs precisely to the non-contact suspension working mode can a proper gap be ensured between the two platforms. Only when the backlash elimination and locking mechanism runs precisely to the contact locking working position can the two platforms be pressed tightly with an appropriate torque so as not to be unable to unlock. Therefore, how to design the drive control strategy of the backlash elimination and locking mechanism is the key point to be considered. At the same time, it is also necessary to consider the processing strategy after the mechanism loses position information after reset or initialization.

[0004] In addition, due to the signal "jitter" phenomenon at the signal edge of the Hall sensor, the positioning calibration is inaccurate. At the same time, when the mechanism runs to the contact working position, the motor will have obvious step loss due to the blocked stroke. Summary of the Invention

[0005] The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, and providing an optimized drive control and positioning method for a backlash elimination and locking mechanism for a space spacecraft.

[0006] The technical solution adopted by the present invention is: an optimized drive control and positioning method for a backlash elimination and locking mechanism for a space spacecraft, wherein a first Hall sensor is installed at the contact working position of the two parts of the backlash elimination and locking mechanism, and a second Hall sensor is installed at the non-contact working position. The method of the present invention includes a first closed-loop mode: the steps for the backlash elimination and locking mechanism to run to the locking working position:

[0007] S1. Define the signal output by the first Hall sensor as the first limit signal, and the ground sets parameters for the drive circuit of the backlash elimination and locking mechanism by means of fixed address parameter injection. The parameters include rotational speed pulse frequency, current grading, drive direction, first predetermined step value, and first scale step value; set the initial value of the scale step value, the initial value of the control period counter HallCnt5 when the first limit signal is valid is 0, and the initial value of the scale step calibration flag Hall_triggered is 0;

[0008] In each control period of the backlash elimination and locking mechanism, execute:

[0009] S2. The power-on circuit sends the drive current of the motor in the backlash elimination and locking mechanism, causing the backlash elimination and locking mechanism to operate according to the rotation speed pulse frequency, current grading, and drive direction injected from the ground. The scale step value decreases in each control cycle. If the scale step value ≤ the preset lower limit, it is considered that the task fails and the operation ends; otherwise, it enters S3.

[0010] S3. Determine whether the first limit signal is valid. If it is valid, enter S4; otherwise, set HallCnt5 to 0 and end the task for this control cycle.

[0011] S4. Determine whether Hall_triggered is 1. If Hall_triggered is not 1, increment the value of HallCnt5 and enter S5; if Hall_triggered is 1, decrement the first predetermined step value and enter S6.

[0012] S5. Determine whether the value of HallCnt5 is greater than or equal to the first preset value. If so, perform scale step positioning calibration: assign the scale step value to the first scale step value; at the same time, set Hall_triggered to 1 and set the current grade to the lowest grade, and control the operation of the backlash elimination and locking mechanism according to the injected rotation speed pulse frequency, drive direction, and lowest grade current. Decrement the first predetermined step value and enter S6; otherwise, do not perform scale step positioning calibration, directly decrement the first predetermined step value, and enter S6.

[0013] S6. Determine whether the first predetermined step value is less than or equal to 0. If so, the backlash elimination and locking mechanism reaches the locking working position, control the motor to stop running, stop the rotation speed pulse output of the backlash elimination and locking mechanism, and the task execution ends; otherwise, end the task for this control cycle.

[0014] Furthermore, the first closed-loop mode is used to run from the upper limit position or the floating working position to the locking working position, and to run from any position to the locking working position; in addition, it is also used for the "zero seeking" positioning function after initialization or reset; the upper limit position is the power-on initial position of the backlash elimination and locking mechanism.

[0015] Furthermore, when the first limit signal is valid in the first closed-loop mode, it indicates that the backlash elimination and locking mechanism reaches the contact working position.

[0016] Furthermore, the first limit signal is a level signal, high level is valid, low level is invalid, and the first limit signal remains valid from the contact working position to the locking working position.

[0017] Furthermore, the rotation speed pulse frequency determines the motor speed, and the current grading determines the motor torque.

[0018] There are three gears: the current in the first gear is the minimum torque, and the torques corresponding to the currents in the second and third gears gradually increase; the driving direction determines the rotation direction of the motor; the first predetermined step value is the number of steps for the backlash elimination and locking mechanism to continue running after reaching the first limit signal.

[0019] The first scale step value is the scale value when the backlash elimination and locking mechanism reaches the contact working position when the first limit signal is valid, so as to overcome the step loss of the motor during operation.

[0020] Furthermore, the method of the present invention includes a second closed-loop mode: the steps for the backlash elimination and locking mechanism to run to the floating working position:

[0021] Step 0T1: Define the signal output by the second Hall sensor as the second limit signal. The ground sets the parameters of the driving circuit of the backlash elimination and locking mechanism by means of fixed-address parameter injection, including the rotational speed pulse frequency, current grading, driving direction, second predetermined step value, and second scale step value; set the initial value of the scale step value, the initial value of the control period counter NoHallCnt5 when the first limit signal is invalid is 0, the starting position of the backlash elimination and locking mechanism is the locking working position, and the initial value of the scale step calibration flag Hall_triggered is 1; in each control period of the backlash elimination and locking mechanism, execute:

[0022] Step T2: The power-on circuit sends out the driving current of the motor in the backlash elimination and locking mechanism. The backlash elimination and locking mechanism runs according to the rotational speed pulse frequency, current grade, and driving direction injected by the ground. The scale step value increases in each control period. If the scale step value ≥ the preset upper limit, it is considered that the task fails and the operation ends; otherwise, enter T3.

[0023] Step T3: Judge whether the second limit signal is valid. If the second limit signal is invalid, enter T4; otherwise, if the second limit signal is valid, the second predetermined step value decreases in each period. Judge whether the second predetermined step value is less than or equal to 0. If so, the backlash elimination and locking mechanism reaches the floating working position, control the motor to stop running, stop the rotational speed pulse output of the backlash elimination and locking mechanism, and the task execution ends; otherwise, the task of this control period ends.

[0024] Step T4: Judge whether the first limit signal is valid. If the first limit signal is invalid, execute T5. If the first limit signal is valid, clear NoHallCnt5, and the task of this control period ends.

[0025] Step T2: The power-on circuit sends out the driving current of the motor in the backlash elimination and locking mechanism. The backlash elimination and locking mechanism runs according to the rotational speed pulse frequency, current grade, and driving direction injected by the ground. The scale step value increases in each control period. If the scale step value ≥ the preset upper limit, it is considered that the task fails and the operation ends; otherwise, enter T3.

[0026] Step T3: Judge whether the second limit signal is valid. If the second limit signal is invalid, enter T4; otherwise, if the second limit signal is valid, the second predetermined step value decreases in each period. Judge whether the second predetermined step value is less than or equal to 0. If so, the backlash elimination and locking mechanism reaches the floating working position, control the motor to stop running, stop the rotational speed pulse output of the backlash elimination and locking mechanism, and the task execution ends; otherwise, the task of this control period ends.

[0027] Step T4: Judge whether the first limit signal is valid. If the first limit signal is invalid, execute T5. If the first limit signal is valid, clear NoHallCnt5, and the task of this control period ends.

[0028] Step T4: Judge whether the first limit signal is valid. If the first limit signal is invalid, execute T5. If the first limit signal is valid, clear NoHallCnt5, and the task of this control period ends.

[0029] Step T4: Judge whether the first limit signal is valid. If the first limit signal is invalid, execute T5. If the first limit signal is valid, clear NoHallCnt5, and the task of this control period ends.

[0030] 5T5. Determine whether Hall_triggered is 1. If Hall_triggered is 1, increment the value of NoHallCnt5 by 1 and proceed to T6. If Hall_triggered is 0, end the task for this control cycle.

[0031] T6. Determine whether the value of NoHallCnt5 is greater than or equal to the second preset value. If so, perform the scale step position calibration: assign the scale step value to the second scale step value; at the same time, set Hall_triggered to 0. Otherwise, end the task for this control cycle.

[0032] Further, the second preset step value in T1 is the number of steps the backlash elimination and locking mechanism continues to run after reaching the second limit signal. The second scale step value is the scale value when the first limit signal is invalid during the process of the backlash elimination and locking mechanism retracting from the locking working position.

[0033] Further, when the second limit signal is valid in the second closed-loop mode, it indicates that the backlash elimination and locking mechanism has run to the non-contact working position.

[0034] Further, the second limit signal in T1 is a level signal, with high level being valid and low level being invalid. The second limit signal remains valid from the non-contact working position to the floating working position.

[0035] Further, the initial value of Hall_triggered inherits the value 1 in the first closed-loop mode. Only after the value of NoHallCnt5 accumulates to 5 is the scale step position calibration performed, and Hall_triggered is cleared to 0.

[0036] The beneficial effects of the present invention compared with the prior art are as follows:

[0037] (1) An optimized drive control and positioning method for a backlash elimination and locking mechanism for a space spacecraft proposed by the present invention includes two closed-loop control modes and can be used for 5 working conditions. Four of the working conditions are for switching between various working positions, and the other working condition is for "zero seeking" positioning after the computer resets and loses steps, covering various common working conditions and being convenient and flexible to switch.

[0038] (2) The present invention uses the method of continuously collecting and determining that the first limit signal is effective or invalid in 5 control cycles to eliminate the problems of inaccurate positioning accuracy caused by the "jitter" phenomenon at the edge of the limit signal and repeated positioning.

[0039] (3) The present invention uses the first scale step value and the second scale step value for scale step position calibration, overcoming the influence caused by the motor losing steps due to the blocked stroke when the backlash elimination and locking mechanism runs to the contact working position. Description of the Drawings

[0040] Figure 1 These are two operating stages of the first closed-loop mode of the embodiment of the present invention;

[0041] Figure 2 This is the flowchart of the tasks per cycle of the first closed-loop mode of the embodiment of the present invention;

[0042] Figure 3 These are two operating stages of the second closed-loop mode of the embodiment of the present invention;

[0043] Figure 4 This is the flowchart of the tasks per cycle of the second closed-loop mode of the embodiment of the present invention. Detailed implementation manners

[0044] The present invention will be further described below in conjunction with the accompanying drawings.

[0045] In the embodiment of the present invention, a first Hall sensor is installed at the contact working position of the backlash elimination and locking mechanism, and a second Hall sensor is installed at the non-contact working position. The signal output by the first Hall sensor is the first limit signal, which is a long pulse signal and remains valid when the backlash elimination and locking mechanism moves from the contact working position to the locking working position. The signal output by the second Hall sensor is the second limit signal, which is a long pulse signal and remains valid when the backlash elimination and locking mechanism moves from the non-contact working position to the floating working position.

[0046] As Figure 1 shown, the first closed-loop mode is that the backlash elimination and locking mechanism runs to the locking working position and includes 2 operating stages:

[0047] 1) The first stage: includes three initial positions. The first is from the upper limit position to the first limit signal being valid, the second is from the floating working position to the first limit signal being valid, and the third is from any position to the first limit signal being valid. In this stage, the backlash elimination mechanism is controlled to run at the rotational speed pulse frequency, current gear, and driving direction injected from the ground until the first limit signal is valid.

[0048] 2) The second stage: starts after the first limit signal is valid. If it is continuously valid for 5 control cycles for the first time (HallCnt5 = 5), then the scale step number positioning calibration is performed, that is, the scale step value is set to the first scale step value. At the same time, the backlash elimination mechanism is controlled to run at the injected rotational speed pulse frequency, driving direction, and 1st gear current; after continuing to run for "the first scale step value" steps, the operation of the first closed-loop mode ends.

[0049] The specific steps are as Figure 2 shown and include:

[0050] S1. The ground sets parameters for the drive circuit of the backlash elimination and locking mechanism through the injection of fixed address parameters, including the rotational speed pulse frequency, current grading, drive direction, the first predetermined step value of 2000, and the first scale step value of 100; set the initial value of the scale step value to 392000, the initial value of the control cycle counter HallCnt5 for the first limit signal to be valid to 0, and the initial value of the scale step calibration flag Hall_triggered to 0;

[0051] In each control cycle of the backlash elimination and locking mechanism, execute:

[0052] S2. The power-on circuit issues the drive current of the motor in the backlash elimination and locking mechanism, causing the backlash elimination and locking mechanism to operate according to the rotational speed pulse frequency, current grading, and drive direction injected by the ground. The scale step value decreases in each control cycle. If the scale step value ≤ -100000, it is considered that the task fails and the operation ends; otherwise, proceed to S3;

[0053] S3. Determine whether the first limit signal is valid. If it is valid, proceed to S4; otherwise, set HallCnt5 to 0 and end the task for this control cycle; S4. Determine whether Hall_triggered is 1. If Hall_triggered is not 1, increment the value of HallCnt5 and proceed to S5; if Hall_triggered is 1, decrement the first predetermined step value and proceed to S6;;

[0054] S5. Determine whether the value of HallCnt5 is greater than or equal to 5. If it is, perform scale step positioning calibration: assign the scale step value to the first scale step value; at the same time, set Hall_triggered to 1 and set the current gear to gear 1, and control the backlash elimination and locking mechanism to operate with the injected rotational speed pulse frequency, drive direction, and gear 1 current. Decrement the first predetermined step value and proceed to S6; otherwise, do not perform scale step positioning calibration, directly decrement the first predetermined step value, and proceed to S6;

[0055] S6. Determine whether the first predetermined step value is less than or equal to 0. If it is, the backlash elimination and locking mechanism reaches the locking working position, control the motor to stop running, stop the rotational speed pulse output of the backlash elimination and locking mechanism, and the task execution ends; otherwise, end the task for this cycle.

[0056] The rotational speed pulse frequency determines the motor speed, the current grading determines the motor torque, including 3 gears: the gear 1 current is the minimum torque, and the torques corresponding to the gear 2 current and the gear 3 current gradually increase; the drive direction determines the motor rotation direction; the first predetermined step value is the number of steps for the backlash elimination and locking mechanism to continue running after reaching the first limit signal; the first scale step value is the scale value when the backlash elimination and locking mechanism reaches the contact working position at the end of the first stage.

[0057] Step S5 determines whether the value of HallCnt5 is greater than or equal to 5: By continuously collecting the first limit signal for 5 control cycles to determine its effectiveness, the purpose is to confirm the authenticity and effectiveness of the first limit signal, eliminate the positioning accuracy problem and repeated positioning problem caused by the "jitter" phenomenon at the edge of the limit signal.

[0058] Hall_triggered in Step S5 is assigned the value of 1 after the value of HallCnt5 accumulates to 5, aiming to ensure that the scale step positioning calibration is only performed once in the first closed-loop mode, that is, only when the first limit signal is valid for 5 consecutive control cycles for the first time.

[0059] As Figure 3 shown, the second closed-loop mode is used to run from the locked working position to the floating working position, including 2 operating stages:

[0060] 1) The first stage: from the locked working position to the second limit signal being valid. The backlash elimination mechanism is controlled to operate with the injected rotational speed pulse frequency, driving direction, and current gear; during the process, after the first limit signal is continuously collected as invalid for 5 control cycles (NoHallCnt5 = 5), the scale step positioning calibration is performed, that is, the scale step value is set to the second scale step value.

[0061] 2) The second stage: after the second limit signal is valid, continue to run "the second predetermined step value" steps, and then end the operation of the second closed-loop mode.

[0062] Specific steps are as Figure 4 shown, including:

[0063] T1. The ground sets parameters for the driving circuit of the backlash elimination and locking mechanism through the injection of fixed address parameters, including rotational speed pulse frequency, current grading, driving direction, the second predetermined step value of 2000, and the second scale step value of 240000; the initial value of the scale step value is set to -2000, the initial value of the control cycle counter NoHallCnt5 for the invalid first limit signal is 0, the starting position of the backlash elimination and locking mechanism is the locked working position, and the initial value of the scale step calibration flag Hall_triggered is 1;

[0064] In each control cycle of the backlash elimination and locking mechanism, execute:

[0065] T2. The power-on circuit issues the driving current of the motor in the backlash elimination and locking mechanism, so that the backlash elimination and locking mechanism operates according to the rotational speed pulse frequency, current gear, and driving direction injected by the ground. The scale step value increases in each control cycle. If the scale step value ≥ 290000, it is considered that the task fails and the operation ends; otherwise, enter T3;

[0066] T3. Determine whether the second limit signal is valid. If the second limit signal is invalid, proceed to T4; otherwise, if the second limit signal is valid, decrement the second predetermined step value by one per cycle. Then, determine whether the second predetermined step value is less than or equal to 0. If so, the backlash elimination and locking mechanism has reached the floating working position, control the motor to stop running, stop the rotational speed pulse output of the backlash elimination and locking mechanism, and the task execution ends; otherwise, the task for this control cycle ends.

[0067] T4. Determine whether the first limit signal is valid. If the first limit signal is invalid, execute T5; otherwise, clear NoHallCnt5, and the task for this cycle ends.

[0068] T5. Determine whether Hall_triggered is 1. If Hall_triggered is 1, increment the value of NoHallCnt5 by 1 and proceed to T6; if Hall_triggered is 0, the task for this cycle ends.

[0069] T6. Determine whether the value of NoHallCnt5 is greater than or equal to 5. If so, perform scale step positioning calibration: assign the scale step value to the second scale step value; at the same time, set Hall_triggered to 0; otherwise, the task for this cycle ends.

[0070] The second predetermined step value is the number of steps for the backlash elimination and locking mechanism to continue running after receiving the second limit signal; the second scale step value is the scale value when the backlash elimination and locking mechanism reaches the contact working position during the retraction process from the locking working position. When the second limit signal is valid, it indicates that the backlash elimination and locking mechanism has reached the non-contact working position.

[0071] The initial value of Hall_triggered inherits the value 1 in the first closed-loop mode. Scale step positioning calibration is only performed after the value of NoHallCnt5 accumulates to 5, and Hall_triggered is cleared to 0. The purpose is to ensure that the scale step positioning calibration is only performed once in the second closed-loop mode, that is, only when the first limit signal is invalid for 5 consecutive control cycles for the first time.

[0072] In T6, to determine whether the value of NoHallCnt5 is greater than or equal to 5: The method of continuously collecting the first limit signal as invalid for 5 control cycles is adopted. The purpose is to confirm that the first limit signal becomes invalid, and to eliminate the problems of inaccurate positioning accuracy caused by the "jitter" phenomenon at the edge of the limit signal and repeated positioning.

[0073] The above embodiments are disclosed, but they are not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention all fall within the protection scope of the technical solution of the present invention.

Claims

1. An optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft. A first Hall sensor is installed at the contact working position of the two parts of the backlash elimination and locking mechanism, and a second Hall sensor is installed at the non-contact working position. It is characterized in that, Including the first closed-loop mode: the step of the backlash-eliminating and locking mechanism running to the locking working position: S1. Define the signal output by the first Hall sensor as the first limit signal. The ground sets parameters for the driving circuit of the backlash-eliminating and locking mechanism by means of fixed-address parameter injection. The parameters include rotational speed pulse frequency, current grading, driving direction, first predetermined step value, and first scale step value. Set the initial value of the scale step value. The initial value of the control period counter HallCnt5 when the first limit signal is valid is 0, and the initial value of the scale step calibration flag Hall_triggered is 0. In each control period of the backlash-eliminating and locking mechanism, execute: S2. The power-on circuit issues the driving current of the motor in the backlash-eliminating and locking mechanism, so that the backlash-eliminating and locking mechanism runs according to the rotational speed pulse frequency, current grading, and driving direction injected by the ground. The scale step value decreases in each control period. If the scale step value ≤ the preset lower limit, it is considered that the task fails and the operation ends; otherwise, enter S3. S3. Judge whether the first limit signal is valid. If it is valid, enter S4; otherwise, set HallCnt5 to 0 and end the task of this control period. S4. Judge whether Hall_triggered is 1. If Hall_triggered is not 1, increment the value of HallCnt5 and enter S5; if Hall_triggered is 1, decrement the first predetermined step value and enter S6. S5. Judge whether the value of HallCnt5 is greater than or equal to the first predetermined value. If so, perform scale step positioning calibration: assign the scale step value to the first scale step value; at the same time, set Hall_triggered to 1 and set the current gear to the lowest gear, and control the backlash-eliminating and locking mechanism to run at the injected rotational speed pulse frequency, driving direction, and lowest gear current. Decrement the first predetermined step value and enter S6. Otherwise, do not perform scale step positioning calibration, directly decrement the first predetermined step value, and enter S6. S6. Judge whether the first predetermined step value is less than or equal to 0. If so, the backlash-eliminating and locking mechanism reaches the locking working position, control the motor to stop running, stop the rotational speed pulse output of the backlash-eliminating and locking mechanism, and end the task execution; otherwise, end the task of this control period. The first closed-loop mode is used to run from the upper limit position or the floating working position to the locking working position, and to run from any position to the locking working position; in addition, it is also used for the "zero seeking" positioning function after initialization or reset; the upper limit position is the power-on initial position of the backlash-eliminating and locking mechanism. In the first closed-loop mode, when the first limit signal is valid, it indicates that the backlash-eliminating and locking mechanism reaches the contact working position. The first limit signal is a level signal, high level is valid, low level is invalid, and the first limit signal remains valid from the contact working position to the locking working position.

2. The optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft according to claim 1, characterized in that, The rotational speed pulse frequency determines the motor speed, and the current grading determines the motor driving torque, including 3 grades: the current in Grade 1 is the minimum torque, and the torques corresponding to the currents in Grade 2 and Grade 3 gradually increase; the driving direction determines the rotation direction of the motor; the first predetermined step value is the number of steps for the backlash elimination and locking mechanism to continue running after reaching the first limit signal; the first scale step value is the scale value when the backlash elimination and locking mechanism reaches the contact working position when the first limit signal is valid, so as to overcome the step loss of the motor during operation.

3. The optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft according to claim 1, characterized in that, Including the second closed-loop mode: the steps for the backlash elimination and locking mechanism to run to the floating working position: T1. Define the signal output by the second Hall sensor as the second limit signal. The ground sets the parameters of the driving circuit of the backlash elimination and locking mechanism by means of fixed address parameter injection, including rotational speed pulse frequency, current grading, driving direction, second predetermined step value, and second scale step value; Set the initial value of the scale step value. The initial value of the control period counter NoHallCnt5 when the first limit signal is invalid is 0. The starting position of the backlash elimination and locking mechanism is the locking working position, and the initial value of the scale step calibration flag Hall_triggered is 1; In each control period of the backlash elimination and locking mechanism, execute: T2. The power-on circuit issues the driving current of the motor in the backlash elimination and locking mechanism. The backlash elimination and locking mechanism runs according to the rotational speed pulse frequency, current grade, and driving direction injected by the ground. The scale step value increases in each control period. If the scale step value ≥ the preset upper limit, it is considered that the task fails and the operation ends; otherwise, enter T3; T3. Judge whether the second limit signal is valid. If the second limit signal is invalid, enter T4; otherwise, if the second limit signal is valid, the second predetermined step value decreases in each period. Judge whether the second predetermined step value is less than or equal to 0. If so, the backlash elimination and locking mechanism reaches the floating working position, control the motor to stop running, stop the rotational speed pulse output of the backlash elimination and locking mechanism, and the task execution ends; otherwise, the task of this control period ends; T4. Judge whether the first limit signal is valid. If the first limit signal is invalid, execute T5. If the first limit signal is valid, clear NoHallCnt5, and the task of this control period ends; T5. Judge whether Hall_triggered is 1. If Hall_triggered is 1, add 1 to the value of NoHallCnt5 and enter T6; if Hall_triggered is 0, the task of this control period ends; T6. Judge whether the value of NoHallCnt5 is greater than or equal to the second predetermined value. If so, perform scale step positioning calibration: assign the scale step value to the second scale step value; at the same time, set Hall_triggered to 0; otherwise, the task of this control period ends.

4. The optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft according to claim 3, characterized in that, The second predetermined step value in T1 is the number of steps for the backlash elimination and locking mechanism to continue running after reaching the second limit signal; the second scale step value is the scale value when the first limit signal is invalid during the process of the backlash elimination and locking mechanism retracting from the locking working position.

5. The optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft according to claim 3, characterized in that, When the second limit signal is valid in the second closed-loop mode, it means that the backlash elimination and locking mechanism runs to the non-contact working position.

6. The optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft according to claim 3, characterized in that, The second limit signal described in T1 is a level signal, which is active at high level and inactive at low level. The second limit signal remains valid continuously from the non-contact working position to the floating working position.

7. The optimized drive control and positioning method for a backlash elimination and locking mechanism of a space spacecraft according to claim 3, characterized in that, The initial value of Hall_triggered inherits the value 1 in the first closed-loop mode. Only after the value of NoHallCnt5 accumulates to 5, the scale step positioning calibration is performed, and Hall_triggered is cleared to 0.

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