A redundant motor servo control system

Abstract

The application discloses a kind of excess degree electric machine servo control system.The disclosed control system system includes processor A, processor B and double-port RAM, the double-port RAM is connected processor A and processor B;Control system is based on the data transmission method and three closed-loop control method of double-port RAM, realizes the ability that backup processor obtains host processor working data in real time;Simultaneously using time-sharing PID method, the problem of motor control performance decline when processor switches is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to motor control technology, in particular to a liquid rocket engine redundancy motor servo control system. BACKGROUND

[0002] In the motor control of the redundancy processor, the host processor always occupies the motor rotary variable acquisition channel, and the backup processor cannot acquire the motor operation data in real time, so that the motor control performance may be reduced during the processor switching process. In order to ensure the smooth motor control and fast response when the redundancy system fails and switches, it is necessary to solve the problems of acquiring the real-time data of the motor control of the host processor by the backup processor, and quickly recovering and maintaining the motor control performance during the switching process of the host processor to the backup processor. SUMMARY

[0003] In view of the defects or deficiencies of the prior art, the present application provides a redundancy motor servo control system.

[0004] Therefore, the control system provided by the present application comprises a processor A, a processor B and a dual-port RAM, wherein the dual-port RAM is connected to the processor A and the processor B.

[0005] The processor A and the processor B are embedded with a feedforward three-closed-loop control method.

[0006] The processor A is a host processor, which controls the motor to work in the absence of failure, and takes over the control of the motor to work when a failure occurs. If the processor B fails, a fault safety state is entered, and all outputs become low at this time.

[0007] The feedforward three-closed-loop control method adopts an angle PID control loop, a speed PID control loop and a current PID control loop to achieve, and the method comprises:

[0008] The current angle of the reducer is collected in real time, and the current angle difference obtained by subtracting the current set angle from the current angle of the reducer is used as the input of the angle PID control loop. The angle PID control loop calculates the speed by using the angle difference. The angle PID control loop periodically outputs the speed calculation result.

[0009] The current speed of the motor is collected in real time, and the current speed difference obtained by subtracting the current speed calculation result from the current speed of the motor is used as the input of the speed PID control loop. The speed PID control loop calculates the current by using the speed difference. The speed PID control loop periodically outputs the current calculation result.

[0010] The current of the motor is collected in real time, the current difference between the current of the motor and the calculation result of the current is taken as the input of the current PID control loop, and the duty cycle is calculated by the current PID control loop using the current difference; and the calculation result of the duty cycle output by the current PID control loop periodically is taken as the servo motor control signal.

[0011] The control algorithm of the current PID control loop is as follows:

[0012]

[0013] Wherein:

[0014] k represents the kth output period of the current PID control loop at the current time, and k is a natural number;

[0015] u(k) represents the output value of the kth output period of the current PID control loop;

[0016] e(k) is the current difference used for calculating u(k);

[0017] e(k-1) is the current difference used for calculating u(k-1), and e(k-1) is initially 0;

[0018] j=0, 1, 2, …, k;

[0019] q represents the qth output period of the angle PID control loop at the current time, and q is a natural number;

[0020] possv(q) represents the set angle used for calculating the output value of the qth output period of the angle PID control loop, and possv(q-1) is initially 0;

[0021] K b represents the feedforward term coefficient, and 70≤K b ≤150;

[0022] K p represents the current proportional coefficient of the current PID control loop;

[0023] K i represents the current integral coefficient of the current PID control loop;

[0024] K d represents the current differential coefficient of the current PID control loop.

[0025] Further, the output period of the angle PID control loop is 5-10 ms, the output period of the speed PID control loop is 1-5 ms, and the output period of the current PID control loop is 0.05-0.1 ms.

[0026] Further, the method of the present application further comprises:

[0027] The parameters of the angle PID control loop are selected according to the size relationship between the current angle difference and the first threshold value, and the speed is calculated after the parameters of the angle PID control loop are selected according to the size relationship between the current angle difference and the first threshold value, and the parameters of the angle PID control loop are selected according to the size relationship between the current angle difference and the first threshold value.

[0028] The value of the angle PID control loop K p when the current angle difference is greater than or equal to the first threshold value is greater than the value of the angle PID control loop K p when the current angle difference is less than the first threshold value,

[0029] The value of the angle PID control loop K i when the current angle difference is greater than or equal to the first threshold value is less than the value of the angle PID control loop K i when the current angle difference is less than the first threshold value,

[0030] The value of the angle PID control loop K p is in the range [10, 50], the value of the angle PID control loop K i is in the range [0, 1], and the value of the angle PID control loop K d is in the range [0, 0.1];

[0031] The parameters of the speed PID control loop are selected according to the size relationship between the current speed difference and the second threshold value, and the current is calculated after the parameters of the speed PID control loop are selected according to the size relationship between the current speed difference and the second threshold value, and the parameters of the speed PID control loop are selected according to the size relationship between the current speed difference and the second threshold value.

[0032] The value of the speed PID control loop K p when the current speed difference is greater than or equal to the second threshold value is greater than the value of the speed PID control loop K p when the current speed difference is less than the second threshold value,

[0033] The value of the speed PID control loop K i when the current speed difference is greater than or equal to the second threshold value is greater than the value of the speed PID control loop K i when the current speed difference is less than the second threshold value,

[0034] The value of the speed PID control loop K p is in the range [0.5, 10], the value of the speed PID control loop K i is in the range [0, 1], and the value of the speed PID control loop K d is in the range [0, 0.1];

[0035] The parameters of the current PID control loop are selected according to the size relationship between the current current difference and the third threshold value, and the duty ratio is calculated after the parameters of the current PID control loop are selected according to the size relationship between the current current difference and the third threshold value, and the parameters of the current PID control loop are selected according to the size relationship between the current current difference and the third threshold value.

[0036] When the current difference is greater than or equal to the third threshold, the current PID control loop K p When the value of K is greater than the current current difference and less than the third threshold, the current PID control loop K... p The possible values ​​of ;

[0037] When the current difference is greater than or equal to the third threshold, the current PID control loop K i When the value of K is less than the current current difference and less than the third threshold, the current PID control loop K... i The value of ,

[0038] Furthermore, the K of the current PID control loop p The value range is [0,1], and the current PID control loop K o The value range is [0,1], and the current PID control loop K d The value range is [0, 0.1].

[0039] Furthermore, the difference between the normalized values ​​of the current angle and the current set angle after normalization is taken as the current angle difference; the difference between the normalized values ​​of the calculated current speed and the collected current motor speed after normalization is taken as the current speed difference; the difference between the normalized values ​​of the calculated current current and the collected current motor current after normalization is taken as the current current difference.

[0040] Furthermore, the system includes: processor A, processor B, processor C, dual-port RAM α, dual-port RAM β, and dual-port RAM γ, wherein dual-port RAM α is connected to processor A and processor B, dual-port RAM β is connected to processor A and processor C, and dual-port RAM γ is connected to processor B and processor C;

[0041] The processors A, B and C are embedded with a feedforward three-closed-loop control method.

[0042] Of the processors A, B, and C, processor A is the main processor. When there is no fault, the main processor controls the motor to work. When a fault occurs, processor B takes over to control the motor. If processor B fails, processor C takes over. If processor C also fails, the system enters a fail-safe state, at which point all outputs become low.

[0043] Furthermore, the processors periodically exchange data. The control processor (i.e. the processor that issues the control signal) outputs a control signal, while other processors perform calculations based on the data provided by the control processor, but do not output control signals.

[0044] Furthermore, the period of data exchange between the processors is consistent with the output period of the current PID control loop.

[0045] Further, when a fault occurs, the parameters K p , K o , K d of the two control loops of the angle PID control loop and the current PID control loop in the non-control processor are taken as fault transition values, and are restored to the parameter values before the fault occurs after a period of time after the fault occurs

[0046] The parameters K p , K o , K d of the angle PID control loop are all taken as 0.

[0047] The parameters K p of the current PID control loop are taken as values smaller than K p before the fault occurs, K i are taken as values larger than K i before the fault occurs, and the values of K p of the current PID control loop are in the range of [0, 1], the values of K i are in the range of [0, 1], and K d is unchanged or in the range of [0, 0.1].

[0048] The application adopts a data transmission method based on a dual-port RAM to realize the ability of the backup processor to acquire working data of the host processor in real time, and adopts a "time-sharing PID" method to solve the problem of the decline of the motor control performance when the processor switches.

[0049] The application adopts a speed feed-forward type three-closed-loop servo motor control method, wherein the control method and control cycle setting of the three-closed-loop can guarantee the accuracy and stability of the angle control of the flow regulating servo unit, thereby guaranteeing the stability of the flow change; the closed-loop control with speed feed-forward can accelerate the response speed of the servo motor and meet the real-time and high responsiveness of the system. In a further scheme, the segmented PID control method first guarantees the index requirement of no overshoot of the flow regulating system, and further accelerates the motor response speed on the basis of guaranteeing no overshoot.

[0050] The control system of the application is suitable for the flow and power system of a liquid rocket engine and can meet the reliability requirement of the power control of a space system. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 FIG. 1 is a structural example diagram of the control system of the application;

[0052] Figure 2 FIG. 2 is a three-closed-loop control structure diagram of the application;

[0053] Figure 3 FIG. 3 is a control effect diagram of an embodiment.

[0054] Figure 4 Control effect diagram for Comparative Example 1;

[0055] Figure 5 Control effect diagram for Comparative Example 2;

[0056] Figure 6 Control object structure diagram for the embodiment. DETAILED DESCRIPTION

[0057] Unless otherwise defined, the terms used herein are understood according to the knowledge of the person of ordinary skill in the relevant art.

[0058] Referring to Figure 1 As shown in the figure, the control system of the present application includes two or three processors, when two processors are used, a dual-port RAM is used to connect the two processors; when three processors are used, three dual-port RAMs are used; taking three processors as an example, the relationship between the processors and the dual-port RAMs is as shown in the figure Figure 2 As shown in the figure, the arrows represent the data flow direction, the three processors are numbered A, B and C, and the three dual-port RAMs are numbered α, β and γ; the dual-port RAM α connects the processor A and the processor B, the dual-port RAM β connects the processor B and the processor C, and the dual-port RAM γ connects the processor A and the processor C; the logical relationship of the three processors is that the A processor (main processor) works first, when a fault occurs, the B processor takes over; if the B processor fails, the C processor takes over; if the C processor also fails, a fault safety state is entered, at this time all outputs become low (safety state); the present application is a servo control technology based on the data interaction of dual-port RAM multi-processor, which is used for redundant embedded processors, and the specific scheme can be realized by using C language.

[0059] A feedforward three-loop control method is embedded in each processor, the feedforward three-loop control method specifically uses a control algorithm with speed feedforward to accelerate the motor control response speed; and the output of the three-loop control uses periodic output to meet the fast response requirement of the motor and effectively control the stable operation of the servo unit. The three-loop control includes a unit angle PID control loop, a motor speed PID control loop and a motor current PID control loop, and the relationship of the three-loop control is shown in the figure Figure 2As shown, the angle (also referred to as position herein) setting of the servo group comes from the user setting, the feedback angle comes from the position sensor (such as a rotary transformer) of the servo group, the output value calculated through the PID algorithm is taken as the set speed value of the speed PID control loop, the feedback speed value comes from the speed sensor (such as a rotary transformer) of the servo motor, and the output value calculated through the PID algorithm of the two is taken as the set current of the current PID control loop; the feedback current of the current PID control loop comes from the three-phase current collected through analog quantity collection, and the duty cycles of the six PWM signals for controlling the servo motor are calculated through the PID algorithm of the two, the on or off of the driving circuit is controlled through the change of the duty cycle of the PWM signal, the magnetic field change is realized, and the servo motor is controlled to run. The closed-loop control algorithm of PID can realize dynamic adjustment and reduce the deviation in the angle steady state section, and the deviation mainly depends on the resolution of the rotary transformer sensor collection and the stability of the system data collection;

[0060] The speed feedforward refers to the speed feedforward term of the current PID control loop, and the control algorithm of the current PID control loop is:

[0061]

[0062] Wherein:

[0063] k represents the kth output period of the current PID control loop at the current time, and k takes a natural number;

[0064] u(k) represents the output value of the kth output period of the current PID control loop;

[0065] e(k) is the current difference value for calculating u(k);

[0066] e(k-1) is the current difference value for calculating u(k-1), and e(k-1) is initially 0;

[0067] j=0, 1, 2, …, k;

[0068] q represents the qth output period of the angle PID control loop at the current time, and q takes a natural number;

[0069] possv(q) represents the set angle used for calculating the output value of the qth output period of the angle PID control loop, and initially, possv(q-1) takes 0;

[0070] K b represents the feedforward term coefficient, 70≤K b ≤150;

[0071] K p represents the current proportional coefficient of the current PID control loop;

[0072] K i represents the current integral coefficient of the current PID control loop;

[0073] K d represents the current differential coefficient of the current PID control loop.

[0074] The algorithm can estimate the target position of the next moment in advance according to the target position of the current moment, so as to shorten the required time for adjustment. In motor control, it means that the motor responds faster and adjusts to the target angle faster under the same speed.

[0075] In the specific scheme, the output period of the three control loops can be determined according to the working parameters of the controlled unit and the control accuracy requirement. Specifically, for different servo units, if the control quality needs to be improved and enhanced, the output period of each closed-loop control can be adjusted to achieve this purpose. For example, the current loop control period can be increased, while the control periods of other closed loops remain unchanged. More specifically, the angle control period is X, 5ms≤X≤10ms, the speed control period is Y, 1ms≤Y≤5ms, and the current control period is Z, 0.05ms≤Z≤0.1ms.

[0076] In the further scheme, the feedforward three-closed-loop control method further includes using a segmented PID control algorithm, that is, in the process of servo motor control, the three control loops respectively select different PID control parameters (including K p , K i , and K d ) for closed-loop control according to corresponding threshold values, thereby further improving the response speed of the motor and ensuring that the control has no overshoot. Specifically, it includes:

[0077] For the angle PID control loop, the parameters of the angle PID control loop are selected according to the size of the current angle difference and the first threshold value, and then the speed is calculated. The selection of the parameters of the angle PID control loop according to the size of the current angle difference and the first threshold value includes:

[0078] When the current angle difference is greater than or equal to the first threshold value, the value of K p is greater than the value of K p when the current angle difference is less than the first threshold value;

[0079] When the current angle difference is greater than or equal to the first threshold value, the value of K i is less than the value of K i when the current angle difference is less than the first threshold value,

[0080] and the value range of K p of the angle PID control loop is [10, 50], the value range of K i is [0, 1], and the value range of K d is [0, 0.1].

[0081] For the speed PID control loop, the parameters of the speed PID control loop are selected according to the size relationship between the current speed difference value and the second threshold value, and then the current is calculated, the selection of the parameters of the speed PID control loop according to the size relationship between the current speed difference value and the second threshold value comprising:

[0082] The value of K p when the current speed difference value is greater than or equal to the second threshold value is greater than the value of K p when the current speed difference value is less than the second threshold value;

[0083] The value of K i when the current speed difference value is greater than or equal to the second threshold value is greater than the value of K i when the current speed difference value is less than the second threshold value,

[0084] And the value range of K p of the speed PID control loop is [0.5, 10], the value range of K i is [0, 1], and the value range of K d is [0, 0.1];

[0085] For the current PID control loop, the parameters of the current PID control loop are selected according to the size relationship between the current current difference value and the third threshold value, and then the duty ratio is calculated, the selection of the parameters of the current PID control loop according to the size relationship between the current current difference value and the third threshold value comprising:

[0086] The value of K p when the current current difference value is greater than or equal to the third threshold value is greater than the value of K p when the current current difference value is less than the third threshold value;

[0087] The value of K i when the current current difference value is greater than or equal to the third threshold value is less than the value of K i when the current current difference value is less than the third threshold value,

[0088] And the value range of K p of the current PID control loop is [0, 1], the value range of K i is [0, 1], and the value range of K d is [0, 0.1].

[0089] In the specific scheme, the first threshold value, the second threshold value and the third threshold value can be selected according to the working parameters of the unit and the control accuracy requirement.

[0090] In some schemes, the angle, rotation speed and current are normalized, which can ensure that the PID parameters of the controller can adapt to most servo motors, and the control parameters do not need to be determined again when the motor type is changed, thereby maximizing the applicability of the parameters. For the scheme using normalized data, in the segmented PID control algorithm, the first threshold is 0.3, the second threshold is 0.2, and the third threshold is 0.015.

[0091] In some preferred schemes, the processors in the control system of the application periodically or in real time interact with each other, and through the data interaction, the working processor outputs the control signal, and the other processors calculate according to the data given by the working processor, but do not output the control signal. The system periodically or in real time interacts with the control data, ensures that the backup processor can also obtain the data required for current control, and when the switching occurs, because the synchronous calculation is always performed, the control can be quickly taken over, the disturbance-free switching is achieved, and the system stability is improved.

[0092] In specific schemes, to realize the stable and reliable data exchange between the processors connected by the dual-port RAM, the dual-port RAM is divided into a low address area and a high address area according to the address height, the low address area is written by the processor connected to the left end and read by the processor connected to the right end, and the high address area is read by the processor connected to the left end and written by the processor connected to the right end. For example, three processors are provided, in specific schemes, the dual-port RAMs α, β and γ are divided into two areas according to the high and low addresses, the high address area of the dual-port RAM α is identified as α1 and written by the processor A and read by the processor B, the low address area of the dual-port RAM α is identified as α2 and written by the processor B and read by the processor A, the high address area of the dual-port RAM β is identified as β1 and written by the processor B and read by the processor C, the low address area of the dual-port RAM β is identified as β2 and written by the processor C and read by the processor B, the high address area of the dual-port RAM γ is identified as γ1 and written by the processor C and read by the processor A, and the low address area of the dual-port RAM γ is identified as γ2 and written by the processor A and read by the processor C. In this way, the host processor writes data to the two RAM areas that can be accessed, and the other two backup processors can read the data, that is, the data interaction is completed. For example, when the processor A works, the processor A writes data to α1 and γ2, the processor B reads α1, and the processor C reads γ2, and the data of the current processor A is obtained.

[0093] The interaction data includes all control data, such as the regulator setting angle, the regulator measured angle, the motor setting rotating speed, the motor measured rotating speed, the motor electrical angle, the instruction content, the instruction count, the engine current working state, the main processor "three closed loop" control result, etc. Each data is written to the corresponding address of the dual-port RAM, and other backup processors know the meaning represented by the data by reading the data of the corresponding address. For example, as shown in Table 1, the starting address of the processor to the external dual-port RAM is 0x100000, and the addressing range is 0x1000. The address 0x100000-0x100800 is the low address area, and the address 0x100801-0x101000 is the high address area.

[0094] Table 1: Dual-port RAM interaction data table

[0095]

[0096]

[0097] In a further scheme of the above scheme, the data interaction period of each processor is consistent with the control period or output period of the current PID control loop, so that the data of the main processor can be obtained during backup current loop control. The data is obtained before control and then used for control calculation, so that the backup processor can obtain the current effective measurement data before each control calculation.

[0098] In a further scheme, when a fault occurs, the parameters K p , K i , and K d of the angle PID control loop and the current PID control loop in the non-main processor are taken as fault transition values, the relationships of the current, rotating speed, and angle required for motor operation are switched and quickly stabilized, and the parameter values of each processor before the fault occurs are restored after a period of time (the time length can be selected according to the circuit characteristics) after the fault occurs. The parameters of the two control loops take fault transition values as follows:

[0099] The parameters K p , K i , and K d of the angle PID control loop are all taken as 0.

[0100] The parameter K p of the current PID control loop takes a smaller value than K p before the fault occurs, the parameter K i of the current PID control loop takes a larger value than K i before the fault occurs, and the value range of K p of the current PID control loop is [0, 1], the value range of K i of the current PID control loop is [0, 1], and the value range of K dInvariable or value range [0, 0.1].

[0101] All parameters of the angle PID control loop and the current PID control loop are set as "transition PID" parameters, because when the processor switches, the original control circuit stops outputting, the motor has no driving current and is in a free deceleration process, at this time the backup processor takes over, the circuit re-outputs, and the current goes from zero to one; in a period of time after the switch, by changing the PID parameters, the process can be accelerated, and the current can reach the required rated current more quickly, so as to make the motor control stable as soon as possible. Since the data of the host processor motor control has been obtained through the dual-port RAM before the switch and used for backup processor closed-loop calculation, after the switch, the backup processor can continue to calculate on the basis of the working processor closed-loop calculation, thereby avoiding the motor running jitter problem caused by the discontinuity of the control quantity. After a period of time of processor switching, the working circuit is stable, the position closed-loop and current closed-loop PID parameters are changed back to the original parameters during normal control, and the motor enters the normal control stage.

[0102] Embodiment 1:

[0103] The control system structure diagram of this embodiment is shown in Figure 1 The control system is used to control the servo unit in the liquid rocket power system flow regulating servo control system shown in Figure 6 The liquid rocket engine motor controller controls the change of the angle of the regulator by driving the servo motor to run, so as to realize engine starting, stage regulation and rapid shutdown control; the system consists of an upper computer (computer), a cable (communication, power supply, control, acquisition), a controller, a power supply, a servo unit and a flow regulator, wherein the servo unit consists of a servo motor, a reducer, a brake and a feedback device (sensor);

[0104] The working principle is as follows: the upper computer sends control commands to the controller through the communication cable, and receives the motor working data and telemetry data uploaded by the controller; the power supply supplies power to the controller through the power cable, and the controller supplies power to the servo unit through the internal power management module; when the servo unit is not started, the brake is closed, and when the servo unit is started, the brake is opened; the reducer of the servo unit is connected to the flow regulator through a mechanical gear structure, the servo motor rotates to drive the regulator to rotate, and the flow regulation of the liquid rocket engine is realized.

[0105] The angle PID control loop outputs the rotation speed calculation result every 5 ms in this embodiment; the rotation speed PID control loop outputs the current calculation result every 1 ms; the current PID control loop outputs the duty cycle calculation result as the servo motor control signal every 0.1 ms; the processors periodically exchange data, the working processor outputs the control signal, the other processors calculate according to the data given by the working processor but do not output the control signal, and the period of data exchange of the processors is consistent with the output period of the current PID control loop;

[0106] The current PID control loop has a rotation speed feedforward term in this embodiment, wherein K b = 100;

[0107] In this embodiment, the normalized data of the angle, rotation speed and current are used for corresponding control, and the segmented PID control algorithm is used, and the selection scheme of the parameters of the three control loops is as follows:

[0108] The angle PID control loop selects the control parameters according to the size relationship between the current normalized angle difference and the first threshold value 0.3: if the current normalized angle difference is greater than or equal to 0.3, K p = 25, K i = 0, K d = 0, and if the current normalized angle difference is less than 0.3, K p = 15, K i = 0.01, K d = 0;

[0109] The rotation speed PID control loop selects the control parameters according to the size relationship between the current normalized rotation speed difference and the second threshold value 0.2: if the current normalized rotation speed difference is greater than or equal to 0.2, K p = 2, K i = 0.01, K d = 0, and if the current normalized rotation speed difference is less than 0.2, K p = 1.5, K i = 0.002, K d = 0;

[0110] The current PID control loop selects the corresponding control parameters according to the size relationship between the current normalized current difference and the third threshold value 0.015: if the current normalized current difference is greater than or equal to 0.015, K p = 0.4, K i = 0.005, K d = 0, and if the current normalized current difference is less than 0.015, K p = 0.2, K i = 0.01, K d = 0;

[0111] The non-master processor adopts a temporary segmentation strategy, and the parameter K of the speed PID control loop is set to 0.2 p , K i , K d , and the parameter K of the current PID control loop is set to 0. p The value of K is smaller than the value of K before the fault occurs. p The value of K is smaller than the value of K before the fault occurs. i The value of K is larger than the value of K before the fault occurs. o The value of K is larger than the value of K before the fault occurs. p The value range of K is 0.2, and the value range of K i is 0.15, and the value of K d is unchanged. After a period of 200ms after the fault, the parameter values of the two control loops are restored to the parameter values before the fault, and the parameter values of the two control loops are set to the fault transition values:

[0112] The speed set (i.e. the input of the speed PID control loop) and the speed feedback of the control process are collected to obtain the control effect as shown in Figure 3 .

[0113] Comparative Example 1:

[0114] The difference between this comparative example and Example 1 is that the control system includes three processors, and the double-port data interaction between the processors is not used. When a fault occurs, manual switching is performed, and the control effect is as shown in Figure 4 .

[0115] Comparing Figure 3 and 4 , it can be seen that when the motor is continuously running at the rated speed, the processor is switched, and it can be seen that after using the double-port RAM data interaction, the motor switching is basically smooth, and except for a little disturbance, the speed does not decrease significantly. Without using the double-port RAM data interaction, the speed decreases significantly, and the minimum speed decreases to about 5600rpm, and the rated speed is 6450rpm, and the effect is obvious.

[0116] Comparative Example 2:

[0117] The difference between this comparative example and Comparative Example 1 is that the temporary segmentation strategy is not used, and the control effect is as shown in Figure 5 .

[0118] Comparing Figure 4 and 5 , it can be seen that when neither of the double-port RAM data interactions is used, the temporary segmentation PID method is used when switching the processor, and the speed decreases to about 5600rpm, and then recovers to the rated speed. When the temporary segmentation PID method is not used when switching the processor, the speed decreases to about 4760rpm at most, which shows that the temporary segmentation PID method can reduce the trend of speed decrease.

Claims

1. A redundant motor servo control system, comprising: The system comprises a processor A, a processor B and a dual-port RAM connecting the processor A and the processor B; The processor A and the processor B are embedded with a feedforward three-closed-loop control method; The processor A is a main processor, which controls the motor to work when no fault occurs; when a fault occurs, the processor B takes over the control of the motor to work; if the processor B fails, a fault safety state is entered, at which time all outputs become low levels; The feedforward three-closed-loop control method adopts an angle PID control loop, a speed PID control loop and a current PID control loop to realize, and the method comprises: Real-time collection of the reducer angle, difference between the current angle of the reducer and the current set angle, and the current angle difference obtained after the difference is taken as the input of the angle PID control loop, the angle PID control loop calculates the speed by using the angle difference; the angle PID control loop periodically outputs the speed calculation result; Real-time collection of the motor speed, difference between the current speed of the motor and the current speed calculation result, and the current speed difference obtained after the difference is taken as the input of the speed PID control loop, the speed PID control loop calculates the current by using the speed difference; the speed PID control loop periodically outputs the current calculation result; Real-time collection of the motor current, difference between the current current of the motor and the current current calculation result, and the current current difference obtained after the difference is taken as the input of the current PID control loop, the current PID control loop calculates the duty ratio by using the current difference; the current PID control loop periodically outputs the duty ratio calculation result as the servo motor control signal; The control algorithm of the current PID control loop is: ； Wherein: k represents the kth output period of the current PID control loop at the current time, k is a natural number; u(k) represents the output value of the kth output period of the current PID control loop; e(k) is the current difference used to calculate u(k); e(k-1) is the current difference used to calculate u(k-1), e(k-1) is initially 0; =0,1,2，…，k； q represents the qth output period of the angle PID control loop at the current time, q is a natural number; set_angle(q) represents a set angle used in the calculation of the output value of the qth output cycle of the angle PID control loop, at the initial time, is taken as 0; represents the feedforward term coefficient, 70≤ ; denotes the current scale factor; denotes the current integration factor; represents the current differential coefficient.

2. The over-dimensioned motor servo control system as recited in claim 1, wherein, The output period of the angle PID control loop is 5-10 ms; the output period of the speed PID control loop is 1-5 ms; and the output period of the current PID control loop is 0.05-0.1 ms.

3. The over-dimensioned motor servo control system as recited in claim 1, wherein, The method further comprises: Selection of the parameters of the angle PID control loop according to the size relationship between the current angle difference and the first threshold value to calculate the speed, which comprises: the value of the angle PID control loop when the current angle difference is greater than or equal to the first threshold the value of the angle PID control loop when the current angle difference is less than the first threshold the value of the angle PID control loop when the current angle difference is less than the first threshold the value of the angle PID control loop when the current angle difference is greater than or equal to the first threshold the value of the angle PID control loop when the current angle difference is less than the first threshold the value of the angle PID control loop when the current angle difference is less than the first threshold and the value range of the angle PID control loop's is [10, 50], the value range of the angle PID control loop's is [0, 1], the value range of the angle PID control loop's is [0, 0.1]; Selection of the parameters of the speed PID control loop according to the size relationship between the current speed difference and the second threshold value to calculate the current, which comprises: the value of the speed PID control loop when the current speed difference is greater than or equal to the second threshold the value of the speed PID control loop when the current speed difference is less than the second threshold the value of the speed PID control loop when the current speed difference is less than the second threshold the value of the speed PID control loop when the current speed difference is greater than or equal to the second threshold the value of the speed PID control loop when the current speed difference is less than the second threshold the value of the speed PID control loop when the current speed difference is less than the second threshold and the value range of the speed PID control loop's is [0.5, 10], the value range of the speed PID control loop's is [0, 1], the value range of the speed PID control loop's is [0, 0.1]; Selection of the parameters of the current PID control loop according to the size relationship between the current current difference and the third threshold value to calculate the duty ratio, which comprises: the value of the current PID control loop when the current difference is greater than or equal to the third threshold the value of the current PID control loop when the current difference is less than the third threshold the value of the current PID control loop when the current difference is less than the third threshold the value of the current PID control loop when the current difference is greater than or equal to the third threshold the value of the current PID control loop when the current difference is less than the third threshold the value of the current PID control loop when the current difference is less than the third threshold and the value range of the current PID control loop's is [0, 1], the value range of the current PID control loop's is [0, 1], the value range of the current PID control loop's is [0, 0.1].

4. The over-dimensioned motor servo control system as recited in claim 1, wherein, Normalization of the current angle of the reducer and the current set angle respectively, and difference between the normalized values is taken as the current angle difference; The difference between the normalized value of the current speed calculation result and the normalized value of the collected current speed of the motor is taken as a current speed difference value. The difference between the normalized value of the current speed calculation result and the normalized value of the collected current speed of the motor is taken as a current speed difference value.

5. The over-dimensioned motor servo control system as recited in claim 1, wherein, The system comprises a processor A, a processor B, a processor C, a dual-port RAM α, a dual-port RAM β and a dual-port RAM γ, the dual-port RAM α is connected with the processor A and the processor B, the dual-port RAM β is connected with the processor A and the processor C, and the dual-port RAM γ is connected with the processor B and the processor C; The processor A, the processor B and the processor C are embedded with a feedforward three-closed-loop control method; The processor A is a main processor, the main processor controls the motor to work when there is no fault, the processor B takes over the control of the motor to work when a fault occurs, the processor C takes over when the processor B is faulty, and all outputs become low when the processor C is also faulty.

6. The over-dimensioned motor servo control system as recited in claim 1, wherein, Each processor periodically interacts with data, the main processor outputs control signals, and other processors calculate according to the data given by the main processor but do not output control signals.

7. The over-dimensioned motor servo control system of claim 1, wherein, The period of data interaction of each processor is consistent with the output period of the current PID control loop.

8. The over-dimensioned motor servo control system as recited in claim 1, wherein, When a fault occurs, the parameters of two control loops of the angle PID control loop and the current PID control loop in the non-main processor 、 、 Take the fault transition value, and restore the parameter value before the fault occurs after a period of time after the fault occurs, the parameters of the two control loops 、 、 The fault transition value is: Parameters of the angle PID control loop , , are all taken as 0; Parameters of the current PID control loop is smaller than that before the fault occurs is smaller than that before the fault occurs is larger than that before the fault occurs is larger than that before the fault occurs is in the range of [0, 1], is in the range of [0, 1], is unchanged or in the range of [0, 0.1].

Images