Cascade position follow-up control method for servo turntable

Abstract

The invention discloses a servo turntable cascade position follow-up control method, and relates to the technical field of servo turntable equipment position tracking control, and the method comprises the steps: building a double-ring closed-loop control system of a turntable position ring and a current ring, and enabling the position ring to collect a real-time position signal through a rotary transformer; performing interpolation design on the external given position value P, and calculating an external position given value Pg (k) in each control period; a planning closed loop in which an internal position given value tracks an external position given value is constructed, an integral separation PI control algorithm is adopted, amplitude limiting is carried out on output of a PI controller, meanwhile, speed and acceleration are limited, and output of the closed loop is the internal position given value and serves as input of a servo turntable double-closed-loop control system; the problem of jitter caused by overlong sending period of the external given value can be avoided, the stability of the servo turntable system is improved, and the required tracking precision can be achieved by adopting the PI control algorithm and setting reasonable control parameters.

Description

Technical Field

[0001] The invention relates to the technical field of position tracking control of servo turntable equipment, and in particular to a cascade position following control method for a servo turntable. Background Art

[0002] As the requirements for position tracking control of servo turntable equipment continue to increase, higher requirements are placed on the performance and reliability of the servo turntable to adapt to situations where the external position set value sending cycle is too long and has large changes.

[0003] When the sending cycle of the external given value is too long, the servo turntable is prone to jamming during operation; when the external given value changes significantly, the servo turntable is prone to out-of-tolerance protection, affecting the reliability of the servo turntable's operation. Summary of the invention

[0004] In view of the above technical problems, in order to improve the operational reliability of the servo turntable during the position following process, the present invention proposes a servo turntable cascade position following control method, comprising the following steps:

[0005] S1. Build a dual-loop closed-loop control system of the turntable position loop and current loop. The position loop uses a rotary transformer to collect real-time position signals;

[0006] S2. Perform interpolation design on the external given position value P to calculate the external position given value P in each control cycle. g (k);

[0007] S3. Construct a planning closed-loop circuit in which the internal position given value tracks the external position given value, adopt an integral separation PI control algorithm, and limit the output of the PI controller. At the same time, limit the speed and acceleration. The output of the closed-loop circuit is the internal position given value, which serves as the input of the servo turntable dual closed-loop control system.

[0008] Furthermore, the current loop in S1 adopts a PI controller, and the expression of the PI controller is as follows:

[0009] e i (k)=u(k)-K*i(k)

[0010] I i (k) = I i (k)+K ii *e i (k)

[0011] iout(k)=K ip *e i (k)+I i (k)

[0012] Among them, e i(k) is the current difference, u(k) is the current loop input, K is the current feedback coefficient, I i (k) is the integral term in the current loop PI, K ip is the current loop proportionality coefficient, K ii is the current loop integral coefficient, and iout(k) is the current output.

[0013] Furthermore, the position loop in S1 adopts a PID controller, and the expression of the PID controller is as follows:

[0014] e θ (k) = θ p (k)-θ′(k)

[0015] I θ (k) = I θ (k)+Kθ i *e θ (k)

[0016] u(k)=K θp *e θ (k)+I θ (k)+K θd *(e θ (k)-e θ (k-1))

[0017] Among them, e θ (k) is the position difference, θ p (k) is the position loop input value, θ′(k) is the actual feedback position value of the resolver, I θ (k) is the integral term in the position loop PID, K θp is the position loop proportional coefficient, K θi is the position loop integral coefficient, K θd is the differential coefficient of the position loop, u(k) is the position loop output and current loop input.

[0018] Furthermore, the position given value P in S2 g (k) The calculation method is as follows:

[0019] P g (k)=P(k1-1)+(P(k1)-P(k1-1)) / (T g / T)

[0020] Among them, P g (k) is the position given value for each control cycle, k is the number of control cycle steps, k1 is the number of external position given steps, T is the control cycle, T g is the sending period of the external given position, and P(k1) is the external given position at time k1.

[0021] Furthermore, the formula for constructing a planning closed loop in which the internal position given value tracks the external position given value in S3 is as follows:

[0022] P e (k)=P(k)-P G (k)

[0023] I f (k) = I f (k-1)+k i *P e (k)*T

[0024] When P e (k)>P r hour:

[0025] I f (k) = 0

[0026] The points limits are as follows:

[0027] -I fmax ≤I f (k)≤I fmax

[0028] PI control output value:

[0029] V1(k)=k p *P e (k)+I f (k)

[0030] -V Max ≤V1(k)≤V max

[0031] The internal speed planning value is:

[0032] V g (k) = V g (k-1)+K*A*T

[0033] -V1(k)≤V g (k)≤V1(k)

[0034]

[0035] The internal position given value is:

[0036] P G (k) = P G (k-1)+V g (k)*T

[0037] Among them, P G (k) is the internal position given value, V g(k) is the internal speed planning value, V1(k) is the PI controller output value, V max is the maximum speed limit, A is the set acceleration value, k p and k i is the proportional coefficient and integral coefficient of the PI controller, I f (k) is the integral amount, I fmax is the integral limit, P e (k) is the difference between the external given value and the internal given value.

[0038] Compared with the prior art, the present invention has the following advantages: (1) Compared with the traditional control method, the servo turntable cascade position following control method proposed in the present invention can adapt to the situation where the external given value cycle is too large and avoid the jamming situation; (2) The servo turntable cascade position following control method proposed in the present invention, by constructing a planning closed-loop circuit for the internal position given value to track the external position given value, plans the internal position given value, and can avoid the over-tolerance protection caused by excessive changes in the external given value, thereby improving the reliability of the servo turntable position following; (3) The present invention can avoid the jitter problem caused by the excessively long sending cycle of the external given value, and can also avoid the over-tolerance protection caused by abnormal external given values, thereby improving the stability of the servo turntable system. By adopting the PI control algorithm and setting reasonable control parameters, the required tracking accuracy can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the turntable control system of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0041] Example: Figure 1 A servo turntable cascade position follow-up control method shown in the figure comprises the following steps:

[0042] S1. Build a dual-loop closed-loop control system of the turntable position loop and current loop. The position loop uses a rotary transformer to collect real-time position signals;

[0043] S2. Perform interpolation design on the external given position value P to calculate the external position given value P in each control cycle. g (k);

[0044] S3. Construct a planning closed-loop circuit in which the internal position given value tracks the external position given value, adopt an integral separation PI control algorithm, and limit the output of the PI controller. At the same time, limit the speed and acceleration. The output of the closed-loop circuit is the internal position given value, which serves as the input of the servo turntable dual closed-loop control system.

[0045] The current loop in S1 adopts a PI controller, and the expression of the PI controller is as follows:

[0046] e i (k)=u(k)-K*i(k)

[0047] I i (k) = I i (k)+K ii *e i (k)

[0048] iout(k)=K ip *e i (k)+I i (k)

[0049] Among them, e i (k) is the current difference, u(k) is the current loop input, K is the current feedback coefficient, I i (k) is the integral term in the current loop PI, K ip is the current loop proportionality coefficient, K ii is the current loop integral coefficient, and iout(k) is the current output.

[0050] The position loop in S1 uses a PID controller, and the expression of the PID controller is as follows:

[0051] e θ (k) = θ p (k)-θ′(k)

[0052] I θ (k) = I θ (k)+Kθ i *e θ (k)

[0053] u(k)=K θp *e θ (k)+I θ (k)+K θd *(e θ (k)-e θ (k-1))

[0054] Among them, e θ (k) is the position difference, θ p (k) is the position loop input value, θ′(k) is the actual feedback position value of the resolver, Iθ (k) is the integral term in the position loop PID, K θp is the position loop proportional coefficient, K θi is the position loop integral coefficient, K θd is the differential coefficient of the position loop, u(k) is the position loop output and current loop input.

[0055] Position given value P in S2 g (k) The calculation method is as follows:

[0056] P g (k)=P(k1-1)+(P(k1)-P(k1-1)) / (T g / T)

[0057] Among them, P g (k) is the position given value for each control cycle, k is the number of control cycle steps, k1 is the number of external position given steps, T is the control cycle, T g is the sending period of the external given position, and P(k1) is the external given position at time k1.

[0058] The formula for constructing a planning closed loop in S3 for tracking the external position given value with the internal position given value is as follows:

[0059] P e (k)=P(k)-P G (k)

[0060] I f (k) = I f (k-1)+k i *P e (k)*T

[0061] When P e (k)>P r hour:

[0062] I f (k) = 0

[0063] The points limits are as follows:

[0064] -I fmax ≤I f (k)≤I fmax

[0065] PI control output value:

[0066] V1(k)=k p *P e (k)+I f (k)

[0067] -V max ≤V1(k)≤C max

[0068] The internal speed planning value is:

[0069] V g (k) = V g (k-1)+K*A*T

[0070] -V1(k)≤V g (k)≤V1(k)

[0071]

[0072] The internal position given value is:

[0073] P G (k) = P G (k-1)+V g (k)*T

[0074] Among them, P G (k) is the internal position given value, V g (k) is the internal speed planning value, V1(k) is the PI controller output value, V max is the maximum speed limit, A is the set acceleration value, k p and k i is the proportional coefficient and integral coefficient of the PI controller, I f (k) is the integral amount, I fmax is the integral limit, P e (k) is the difference between the external given value and the internal given value.

Claims

1. A servo turntable cascade position follow-up control method, characterized in that: The following steps are involved: S1. Build a dual-loop closed-loop control system of the turntable position loop and current loop. The position loop uses a rotary transformer to collect real-time position signals; S2. Perform interpolation design on the external given position value P to calculate the external position given value P in each control cycle. g (k); S3. Construct a planning closed-loop circuit in which the internal position given value tracks the external position given value, adopt an integral separation PI control algorithm, and limit the output of the PI controller. At the same time, limit the speed and acceleration. The output of the closed-loop circuit is the internal position given value, which serves as the input of the servo turntable dual closed-loop control system.

2. A servo turntable cascade position follow-up control method as claimed in claim 1, characterized in that: The current loop in S1 adopts a PI controller, and the expression of the PI controller is as follows: e i (k)=u(k)-K*i(k) I i (k)=I i (k)+K ii *e i (k) iout(k)=K ip *e i (k)+I i (k) Among them, e i (k) is the current difference, u(k) is the current loop input, K is the current feedback coefficient, I i (k) is the integral term in the current loop PI, K ip is the current loop proportionality coefficient, K ii is the current loop integral coefficient, and iout(k) is the current output.

3. A servo turntable cascade position follow-up control method as claimed in claim 1, characterized in that: The position loop in S1 adopts a PID controller, and the expression of the PID controller is as follows: e θ (k)=θ p (k)-θ′(k) I θ (k)=I θ (k)+Kθ i *to θ (f) u(k)=K θp *e θ (k)+I θ (k)+K θd *(e θ (k)-e θ (k-1)) Among them, e θ (k) is the position difference, θ p (k) is the position loop input value, θ′(k) is the actual feedback position value of the resolver, I θ (k) is the integral term in the position loop PID, K θp is the position loop proportional coefficient, K θi is the position loop integral coefficient, K θd is the differential coefficient of the position loop, u(k) is the position loop output and current loop input.

4. A servo turntable cascade position follow-up control method as claimed in claim 1, characterized in that: The position given value P in S2 g (k) The calculation method is as follows: P g (k)=P(k1-1)+(P(k1)-P(k1-1)) / (T g / T) Among them, P g (k) is the position given value for each control cycle, k is the number of control cycle steps, k1 is the number of external position given steps, T is the control cycle, T g is the sending period of the external given position, and P(k1) is the external given position at time k1.

5. A servo turntable cascade position follow-up control method as claimed in claim 1, characterized in that: The formula for constructing a planning closed loop for the internal position given value to track the external position given value in S3 is as follows: P e (k)=P(k)-P G (k) I f (k)=I f (k-1)+k i *P e (k)*T When P e (k)>P r hour: I f (k)=0 The points limits are as follows: -I fmax ≤I f (k)≤I fmax PI control output value: V1(k)=k p *P e (k)+I f (k) -V max ≤V1(k)≤V Max The internal speed planning value is: VL(k)=VL(k-1)+K*A*T -V1(k)≤V g (k)≤V1(k) The internal position given value is: P G (k)=P G (k-1)+V g (k)*T Among them, P G (k) is the internal position given value, V g (k) is the internal speed planning value, V1(k) is the PI controller output value, V max is the maximum speed limit, A is the set acceleration value, k p and k i is the proportional coefficient and integral coefficient of the PI controller, I f (k) is the integral amount, I fmax is the integral limit, P e (k) is the difference between the external given value and the internal given value.

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