CN105356823A - Load torque observation and compensation method for servo system - Google Patents

Abstract

The invention provides a load torque observation and compensation method for a servo system. First, the given value of current of a current loop at a previous moment, the motor speed at the current moment and the motor speed at the previous moment are read; then, the observed value of the load torque at the current moment is calculated; and the output of a speed regulator and the given value of current of the current loop are obtained, and the observed value of the load torque is compensated. According to the invention, the capability of the servo system to inhibit disturbance is effectively improved, the design difficulty of the speed regulator is simplified, and the precision of the servo system is improved.

Description

A kind of load torque observation of servomechanism and compensation method

Technical field

The present invention relates to interchange following control system, particularly relate to the observation and compensation method that exchange load torque in servomechanism.

Background technology

Along with the development of modernized war, armament systems improve gradually to the tracking of target and the requirement of disturbance rejection, such as Archibald weapon is when shooting, also need to carry out target following, and design impact moment and will the tracking accuracy of servomechanism be affected, also require that servomechanism is under certain disturbing moment (load torque), has certain tracking accuracy simultaneously.Improve follower system precision about disturbance cancelling moment, conventional method is generally the bandwidth sum open-loop gain as far as possible increasing servomechanism, increases integral element to eliminate steady-state error in speed ring controller.The restriction that the increase of bandwidth is subject to system time constant is limited, and excessive open-loop gain can cause the decline of the stability of a system, and therefore this method improves the ability of disturbance rejection is limited.

Summary of the invention

In order to overcome the deficiencies in the prior art, the invention provides a kind of the load torque observation and the compensation method that exchange servomechanism, the load torque of system is observed according to the input and output of servomechanism, and observed quantity is compensated in servomechanism, reduce the impact of disturbance on servomechanism tracking accuracy.

The technical solution adopted for the present invention to solve the technical problems comprises the following steps:

The given value of current value I of the electric current loop of the first step, the upper moment k-1 of reading ^*, and motor speed ω (k) of current time k and a upper moment k-1 and ω (k-1) (k-1);

Second step, calculating wherein, T ₁(k) and T ₁(k-1) intermediate variable in its k moment and k-1 moment is respectively, T _kfor the sampling period of speed ring, time constant is T _c, torque coefficient is K _t;

3rd step, the intermediate variable in calculating k moment wherein, J converts to the total moment of inertia on motor shaft, and F is viscous friction coefficient;

4th step, the load torque measured value in calculating k moment

5th step, the speed regulator in reading k moment export u _ω(k), and the given value of current value calculating k moment electric current loop realize the compensation of load torque measured value.

The invention has the beneficial effects as follows: by interchange servo system load torque observe of the present invention and compensation method, effectively can improve the rejection ability of servomechanism to disturbance, simplify the design difficulty of speed regulator, and the precision of servomechanism can be improved.

Embodiment

Below in conjunction with embodiment, the present invention is further described, the present invention includes but be not limited only to following embodiment.

The present invention establishes interchange servomechanism electric current loop to be simplified to inertial element, and time constant is T _cif torque coefficient is K _t, total moment of inertia of converting on motor shaft is J, and viscous friction coefficient is F, then the concrete steps realizing servo system load torque observe and compensation method are:

The first step: the given value of current value I reading the electric current loop in a upper moment (k-1 moment) ^*, and the rotational speed omega (k) of current time (k moment) and a upper moment (k-1 moment) motor and ω (k-1) (k-1);

Second step: calculate wherein, T ₁for intermediate variable, T ₁(k) and T ₁(k-1) value in its k moment and k-1 moment is respectively, T _kfor the sampling period of speed ring;

3rd step: calculate wherein, T ₂for intermediate variable, T ₂k () is the value in its k moment;

4th step: computational load torque observe value wherein for the load torque measured value in k moment;

5th step, the speed regulator reading the k moment exports u _ω(k), and the given value of current value I calculating k moment electric current loop ^*(k), namely realize the compensation of load torque measured value.

In embodiments of the invention, as the electric current loop time constant T of servomechanism _c=0.2ms, the sampling period T of speed ring _ktime=1ms (0.001s), then the concrete steps realizing servo system load torque observe and compensation method are:

The first step: the given value of current value I reading the electric current loop in a upper moment (k-1 moment) ^*, and the rotational speed omega (k) of current time (k moment) and a upper moment (k-1 moment) motor and ω (k-1) (k-1);

Second step: calculate $T_1\left(k\right)=\frac{T_1(k-1)}{6}+\frac{5K_T}{6}{I}^{*}(k-1);$

3rd step: calculate $T_2\left(k\right)=J\frac{\mathrm{\ω}\left(k\right)-\mathrm{\ω}(k-1)}{0.001}+F\mathrm{\ω}\left(k\right);$

4th step: computational load torque observe value

5th step, the speed regulator reading the k moment exports u _ω(k), and the given value of current value I calculating k moment electric current loop ^*(k), namely realize the compensation of load torque measured value.

Claims (1)

1. the load torque of servomechanism is observed and a compensation method, it is characterized in that comprising the steps:

The given value of current value I of the electric current loop of the first step, the upper moment k-1 of reading ^*, and motor speed ω (k) of current time k and a upper moment k-1 and ω (k-1) (k-1);

Second step, calculating $T_1\left(k\right)=\frac{T_c}{T_c+T_k}{T}_1(k-1)+\frac{T_k{K}_T}{T_c+T_k}{I}^{*}(k-1),$ Wherein, T ₁(k) and T ₁(k-1) intermediate variable in its k moment and k-1 moment is respectively, T _kfor the sampling period of speed ring, time constant is T _c, torque coefficient is K _t;

3rd step, the intermediate variable in calculating k moment wherein, J converts to the total moment of inertia on motor shaft, and F is viscous friction coefficient;

4th step, the load torque measured value in calculating k moment

5th step, the speed regulator in reading k moment export u _ω(k), and the given value of current value calculating k moment electric current loop realize the compensation of load torque measured value.