RU2381451C1 - Gyrostabiliser adaptive control system - Google Patents

Abstract

FIELD: physics; navigation.

SUBSTANCE: invention relates to designing navigation systems and can be used for controlling asynchronous motors of powered gyrostabilisers with variable kinetic momentum, particularly used in positioning systems of artificial earth satellites (AES). To achieve the given result, the degree of functional connections for each control channel can be separately established before operating the control system and directly during processing, for example each "step" of program-reference-input signals. The above mentioned functionalities in many practically important cases of program control of electric drives of artificial earth satellite gyrostabilisers, from the view point of simplifying the process of setting up and optimising control modes (smoothness of transient processes during launch due to reduction of intensity of electromagnetic processes), give the proposed system an edge over existing engineering solutions.

EFFECT: increase in main quality factors of processing program-reference-input signals in a wide range of destabilising effects on artificial earth satellites, and more specifically speed of operation and accuracy through passive setup (adaptation) of each gyrostabiliser control channel.

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Description

The invention relates to the field of designing instruments for navigation systems and can be used for adaptive control of asynchronous motors of power gyrostabilizers with a variable kinetic moment, used, in particular, in orientation systems of artificial Earth satellites (AES).

In such gyrostabilizers, the flywheel engine (source of kinetic momentum) is accelerated to the rated speed (primary acceleration), and then it is accelerated or decelerated by the commands of the control system relative to the rated speed.

The moment developed by the engine is regulated in proportion to the magnitude of the control signal from the orientation sensor. Similar stabilization methods are recommended for high-precision control systems. Known methods of relay, relay-pulse, proportional control, which are used or can be applied to control flywheel asynchronous motors. In AES control systems of medium accuracy (up to 0.5 ÷ 1 ° in orbits of 200-800 km), relay control methods are currently the most widely used, in which a flywheel induction motor is periodically turned on and off through the power supply circuit of phase windings. In this case, the average power consumed by the engine is P _cf = P _n · Y, where P _n is the pulse power consumed by the engine; Y is the duty cycle of switching on or following the control pulses. Since the engine is completely disconnected from the power source in the pauses between the control pulses, such a system is highly economical. In practice, in the steady state, Y = 0.05 ÷ 0.2.

The main disadvantage of this kind of methods and devices is the insufficient accuracy of the satellite orientation due to the presence of a dead zone and hysteresis of the relay element, the inability to carry out self-adjustment (adaptation) of the control system in a wide range of destabilizing effects on the satellite.

Significantly greater possibilities regarding the accuracy of the satellite orientation are possessed by the methods and devices of proportional control of the torque of the flywheel engine, which include the proposed adaptive control system (ACS) of the gyrostabilizer.

Widely known are methods and circuits for controlling the torque of an induction motor, based on a change in the amplitude of the voltage supplied to the windings of the induction motor in proportion to the control signal. Such devices have a good linear dependence of the motor torque on the magnitude of the control signal, but differ in a significant drawback: due to the fact that the rotor windings of the induction motor are constantly energized and, therefore, constantly consume power. Such devices are extremely economical. The fact is that the flywheel engine of the satellite control system most of the time in the steady state operates in the zone of small signals, while developing a moment of 10-20% of the maximum. Therefore, the constant power consumption of the field windings and the ellipticity of the magnetic field dramatically worsen the energy performance of the flywheel engine.

The most economical devices that regulate the voltage at all phases of the motor. The power consumed in this case varies from zero to maximum depending on the control signal. Devices of this type are known, for example, the following:

1. Petrov B.N. Selected Works. Management of aircraft and spacecraft, t.2. M .: Nauka, 1983, p.303-305.

2. Usyshkin E.I. Pulse Width Modulated Inverter. Electricity, 1968, No. 6.

3. RU 2099665 C1 (Military Academy of Air Defense named after Marshal of the Soviet Union G. Zhukov) 12.20.1997, F41G 7/22.

4. RU 2044274 C1 (Production Association "Housing") 09/20/1995 G01C 25/00.

5. Kalikhman D.M. Fundamentals of the design of controlled bases with inertial sensitive elements for the control of gyroscopic devices. - Saratov: Publishing House of Sarat. Gos. Tech. University, 2001 .-- 336 p.

A common drawback of the methods and devices described in these works is the nonlinearity of the dependence of the torque developed by the motor on the magnitude of the voltage applied to its stator windings. This nonlinearity is generated by the fact that the moment developed by an induction motor, as is known, has a quadratic dependence on the phase voltage

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The nonlinearity of this dependence worsens the dynamic and static indicators of the control system as a whole and significantly complicates its synthesis. To obtain a linear dependence of the moment on the magnitude of the control signal in an induction motor, it is possible to change the frequency, as proposed in the above-mentioned works [1-5]. This, of course, significantly complicates the entire device and does not allow for self-adjustment (adaptation) of the control system in a wide range of destabilizing effects on the satellite.

The proposed system does not have these disadvantages:

- the moment developed by the engine (at a constant speed) is proportional to the magnitude of the control voltage in a wide range of destabilizing effects;

- power consumption: varies approximately linearly from zero when the voltage of the control signal changes from zero to the maximum value, which ensures high energy efficiency.

The main feature of the proposed adaptive gyrostabilizer control system is the joint use of pulse-width control circuits for the phase voltages of an asynchronous motor with a squirrel-cage rotor, ensuring the implementation of the principle of passive adaptation of the control system. At the same time, the variety of real satellite loads determines the need to adjust the ACS parameters in real time, since a preliminary calculation is unlikely to change (significantly increase) the quality of regulation, therefore, in the proposed ACS, it is proposed to perform this setting individually for each phase, not only on the basis of an assessment of the state of the object control (OS) at the moment of regulation (working off ELVs), but also anticipating the state of the OS at subsequent moments of mining the corresponding input ELVs.

Thus, the aim of the invention is to increase the main indicators of the quality of the development of program-setting actions in a wide range of effects of destabilizing effects on satellites, namely speed and accuracy by passive tuning (adaptation) of each gyro stabilizer control channel.

To achieve this goal, the adaptive gyrostabilizer control system comprises a first input transformer, a thyristor switch unit, a controlled rectifier, a first DC voltage filter, a standalone inverter, an uncontrolled reverse current inverter unit, a second DC voltage filter, a reverse inverter and a second input transformer whose input combined with the input of the first input transformer and the input of the charging unit of the switching capacitors of the autonomous inverter and connected to the network, the control input of the thyristor switch unit is connected to the output of the control channel containing phase voltage and current sensors, a current-voltage converter, normalizing devices connected to the corresponding inputs of the summing amplifier, the output of which is connected to the signal input a functional converter, an inverting amplifier, a linear switch, a trigger, differentiating circuits, a pulse shaper, made in the form of a single vibrator, to the clock input of the trigger of the control channel serves the frequency of the mains voltage, the control or counting input of each trigger of each control channel is combined with the control input of the linear key and connected to the output of the relay element with an adjustable hysteresis loop, the input of which is combined with the input of the controlled quantizer and connected to the output of the adder, the first input which is combined with the input of the timing circuit and connected to the output of the second block of program-setting actions, the second input of the adder is connected to the rotation speed sensor a flywheel induction motor, the stator windings of which are connected to the output of the autonomous inverter, the control input of which is connected to the output of the control unit of the autonomous inverter, the signal input of which is connected to the first output of the control unit, the second output of which is connected to the signal input of the rectifier control unit, the output of which is connected to the control input of the controlled rectifier, the control input of the reverse inverter is connected to the output of the control unit of the reverse inverter, while the power supply of the blocks control of the rectifier, autonomous and reverse inverter is carried out from one power supply unit connected to the network, and the operation of these control units is synchronized from the mains voltage, the signal input of the control unit is connected through the comparison circuit to the output of the first block of program-setting actions, the second input of the comparison circuit is connected with a voltage feedback sensor or EMF of the flywheel induction motor, the output of the charging unit of the switching capacitors of the autonomous inverter is connected to the second the signal input of the autonomous inverter, the output of the timing circuitry is connected to the “reset” input of the controlled quantizer, the control inputs of which are connected through the frequency multiplier to the output of the clock frequency adjuster, the output of the controlled quantizer is connected to the first input of the functional converter of each control channel, the second input of the functional converter of each control channel connected through an inverting amplifier to the output of a controlled quantizer.

When conducting patent research from the prior art, no solutions are identified that are identical to the claimed. Therefore, the claimed invention meets the eligibility condition "novelty."

The essence of the claimed invention does not follow explicitly from solutions known from the prior art, therefore, the claimed invention meets the eligibility condition "inventive step".

An example implementation of the proposed control system is shown in figure 1, and figure 2-4 shows examples of the implementation of individual blocks of the control system.

The adaptive gyrostabilizer control system contains: 1 and 9 - the first and second input transformers; 2 - block thyristor switches; 3 - controlled rectifier; 4 and 7 - DC voltage filters; 5 and 8 - autonomous and reverse inverters; 5.1 - block recharging switching capacitors of an autonomous inverter 5; 6 - a group of uncontrolled reverse current inverters; 10 - flywheel asynchronous motor; 11 - voltage feedback sensors or EMF; 12, 14 and 15 - control units for the rectifier, autonomous and reverse inverters; 13 - regulation unit; 16 - power supply; 17 and 29 - the first and second program-setting blocks; 18 is a comparison diagram;

a control channel containing in each control phase (Fig. 1 shows one phase "A"): phase voltage and current sensors (19a and 20a); a current-voltage converter 21a; normalizing devices 22a; a summing amplifier 23a, a functional converter 24a, an inverting amplifier 25a, a linear switch 26a, a trigger 27a, a differentiating circuit 28, 1a, a pulse shaper 28, 2a, made in the form of single-vibrators (for brevity, the designation uses the index "a", indicating that for each phase of the mains voltage - A, B and C there is a similar control channel, the diagram shows only one control channel of phase “A”);

the second block of program-setting actions 29; speed sensor 30; an adder 31; timing circuit 32; clock reference 33; as which network voltage can be used, controlled quantizer 34; 35 frequency multiplier and relay element with adjustable hysteresis loop 36.

Let us consider the operation of the proposed system using an example when, at the initial moment of time, the moment of filing, for example, a step-by-step program-setting action (ELV) from the output of the second block of program-set-up actions 29, the relay element with an adjustable hysteresis loop 36 will produce an Upеi signal, which can be described by the following dependencies:

sign E (t), for | E (t) | ≥a1 for all t> 0;

Upеi =

Upе (i-1), for E (t) ∈ (-a1, а1) for all t> 0;

Where

+1, for E (t)> 0;

sign E (t) = 0, for E (t) = 0;

-1, for E (t) <0;

E (t) is the error signal at the output of the adder 31, E (t) = (U ₁ (t) -U ₂ (1)) Kf (1), Kf (t) is the gain, U ₁ (t) and U ₂ (t) - normalized values of the measured values of (instantaneous) voltages at the output of the speed sensor 30 rotation, the induction motor of the gyro stabilizer flywheel and the second block of program-setting actions 29, respectively,

2 * a1 is the value of the hysteresis zone of the relay element with an adjustable hysteresis loop 36, | a1 | = (k2 / k1) U ₁ (t) and -a1 = - (k2 / k1) U ₂ (t), with k1 and k2 - gains of the respective amplifiers of the rotational speed sensor 30 and the program-setting unit 29.

As can be seen from the above relations, for the case when dE (t) / dt = 0, by storing the previous state of the output value of the relay element 36 U _pe (i-1), for all E (t) ∈ (-a1, a1) , where | 2a1 | ≤ & _Tp is the value of the required (given) accuracy of the ELV testing, eliminating the possibility of losing information about the error signal until entering the deadband or hysteresis of the relay element with an adjustable hysteresis loop 36, which explains the effect of increasing the accuracy of the ELV testing in the mode working out small changes E (t) without the need to calculate Change from error signal change.

In addition, at the initial moment of applying the ELV from the output of block 29, the output of the timing circuit 32 will generate a reset signal that is supplied to the corresponding input of the controlled quantizer 34. This process can be implemented by short-circuiting the keys of the quantizer 34, which bypass the elements of its analog memory. In turn, the actuation of the relay element 36 will lead to the formation of trigger signals in each phase of the control channels along a chain of serially connected trigger 27a, a differentiating circuit 28.1a and a pulse shaper 28.2a, which in this example is implemented as a single-shot. At the same time, a short pulse at its output will lead to switching of the windings of the electric motor 10 to the mains voltage source through a controlled rectifier 3, a constant voltage filter 4 and a stand-alone inverter 5. Figure 2a shows an example of the implementation of a controlled rectifier 3 with a L-shaped smoothing filter or a DC voltage filter 4, designed to power the main group of controlled valves of an autonomous inverter 5. Figure 3 shows an example of the implementation of a group of uncontrolled reverse current valves 6, which can be connected through a L-shaped smoothing filter or a second DC filter 7 to a dependent or reverse inverter 8 (see figure 4, a), which acts as a source of anti-emf having reverse conductivity.

The shown schematic diagram (see figure 3) shows the implementation of a stand-alone inverter 5 with a switching link of capacitors 5.1 cut-off diodes 5.2. At the same time, to increase the noise immunity of the ACS, the unit 5a is charged with a gyrostabilizer by recharging the switching capacitors 5.1 of the autonomous inverter 5. In this implementation of the frequency converter circuit, inverters with other switching links — individual, common per phase, common to the anode and cathode groups of the inverter valves, can be used. for inverter. This implementation does not lead to the formation of a potential connection of the AC inputs of the controlled rectifier 3 and the reverse inverter 8 and does not necessitate the separation of inductors 4.1, 4.2, 7.1 (see Fig. 2, a and 4, a). When powering the links of the frequency converter 3 and 8 from common signs (Fig. 1), inductances should be dispersed over inductances 4.1-4.4 and 7.1-7.2 (see Fig. 2, b and 4, b) located in the anode and cathode groups of valves to ensure the symmetrical work of these groups.

In order to increase the rigidity of the moment characteristic of the stabilization system and the possibility of changing it in function of the program-setting influences, feedback (block 11) on voltage (or EMF) was used. In this case, the required stiffness coefficient of the moment characteristic of the gyrostabilizer can be changed on the basis of a change in the value of the program-setting action coming from the output of the first program-setting unit 17 and the regulation of the gain of the comparison circuit 18. These are the links of the second circuit of the pulse-width regulation of the phase voltages of the flywheel induction motor . In this case, the first circuit of the pulse-width regulation of phase voltages of the flywheel induction motor, including the second block of program-setting actions 29, the adder 31, etc. It operates in conjunction with the second circuit, providing a change in the magnitude of the phase voltage in a given function from program-setting actions in terms of speed and torque. In this case, the self-adjustment or the process of adaptation of the system is carried out on the basis of continuous measurement of the phase currents Ia (Id, Ic), converting their values to voltage using a current-voltage converter 21a. The obtained values of voltages and currents through normalizing devices 22a (in Fig. 1, position 22a, i.e. all examples are given for only one phase “A”) are received at the corresponding inputs of the summing amplifier 23a, at the output of which a difference signal is generated:

Eph (t) = (U _u (1) -U _i (t)) Kph (t),

where Kf (t) is the gain of the summing amplifier 23a, U _u (t) and U _i (t) are the normalized values of the measured values of (instantaneous) voltage and current, respectively. Each of which is obtained at the output of the corresponding normalizing device 22a, implemented, for example, through the use of a push-pull circuit for switching on MOS transistors. In addition, in the circuit of standardizing devices, the transmission coefficient decreases starting from the smallest input signals, and not from a given nominal value, as is the case in controlled limiters. This allows you to normalize the measured values of current and voltage in each phase based on the use of compressive displays of their amplitude values, namely for harmonic:

U _u (t) = Au (t) sinωt and Ui (t) = Ai (t) * sin (ωt-Ф),

providing Au (t) = Ai (t) = A (t) for all t> 0, and this allows us to obtain a harmonic signal of the following form at the output of the summing amplifier 23a: e (t) = 2Asin (Ф / 2) * cos (ωt -F / 2), i.e. we get the normalized differences of the input values of currents and voltages of the corresponding phases.

The signal of the normalized difference e (t) from the output of the summing amplifier 23a is fed to the input of the functional converter 24a, the operation of this block can be described by the following relationships:

+1, for | e (t) |> m (t);

Ф (i) = Ф (i-1), for | е (t) | ∈ [m (t) -n, m (t)];

0, for | e (t) |> m (t) -n;

Where

t _i -t _(i-1) - is a multiple of the frequency of the mains voltage, while the multiplicity of this duration is set <1 / (K _p f _c ), the multiplicity coefficient K _p can be selected, for example, based on the use of the theorem for counting continuous signals in a discrete representation> 2, K and n are constants, f _c is the frequency of the mains voltage.

As can be seen from the above relations for the case dE (t) / dt = 0, by storing the previous state of the output value of the relay element U _pe (i-1), for all E (t) ∈ (-a1, a1), where | 2a1 | ≤ & _Tr is the value of the required (given) accuracy of the ELV testing, eliminating the possibility of losing information about the error signal, which explains the effect of increasing the accuracy of the ELV testing in the mode of processing small changes E (t) without the need to calculate the derivative of the error signal. In this case, the conductivity angle of the thyristors in each phase will be functionally related to the current values of the main indicators of the quality of working out program-setting influences.

Improving the stability of the adaptive gyrostabilizer control system is ensured by synchronizing the operation of blocks 12, 14 and 15 - control units of the rectifier, autonomous and reverse inverter, from the mains voltage. When regulating the output frequency of the converter, the output voltage is changed in accordance with the law of frequency regulation by a simultaneous coordinated change in the control angles of the valves of the autonomous and reverse inverters - α and β, L-shaped smoothing filters 4 and 7 do not interfere with fluctuations in the instantaneous values of the constant currents of the valve groups of the autonomous and reverse inverters.

During operation of the static frequency converter, the voltage on the capacitor of the second filter 7 remains almost constant and does not exceed a certain level, which is no more than 110-120% of the maximum possible amplitude of the first harmonic of the linear voltage at the output of the autonomous inverter 5. The value of the voltage level on the capacitor of the second filter 7 is set using a reverse inverter 8 on the thyristors (see figure 4, a) and the block 15 control the reverse inverter. Reverse inverter 8 can work, for example, with a constant angle β ahead of the inclusion of thyristors. In this case, the voltage level on the capacitor of the second filter 7 will be determined by the input characteristic of the reverse inverter 8 on the thyristors (see Fig. 4, a). To obtain a more stringent characteristic, it is possible to adjust the lead angle β of the reverse inverter so that the voltage across the capacitor of the second filter 7 is constant and does not exceed a predetermined level in all operating modes of the adaptive control system. The signal at the output of the feedback block 11 is formed on the basis of the phase EMF of the flywheel asynchronous motor 10. The signal from the output of the comparison circuit 18 is fed to the input of the control unit 13, the control signals at the outputs of which form the signal for setting the active current i _a (moment) of the flywheel asynchronous motor 10. Thus, an orthogonal component of the stator current is formed, oriented according to the flux linkage of the rotor ψ ₂ .

(see 6. Bessekersky VA, Fabrikant EA Dynamic synthesis of gyroscopic stabilization systems. - L .: Shipbuilding, 1968. - 351 p.).

In turn, the reactive component of the stator current vector i _p is determined by the flux linkage of the rotor ψ ₂ . Accordingly, under the phase EMF in this implementation, EMFs associated with the flux linkage of the rotor ψ _{2 are used} . Therefore, the moment M of the engine 10 is determined by the following expression:

M = K _m ψ ₂ i _a ,

where K _m is the coefficient of proportionality.

The required active and reactive components of the stator current can be determined by using a rotating coordinate system with a speed ω (or with a frequency of stator currents that is proportional to f _c ). Thus, to form the required moment M on the shaft of the flywheel asynchronous motor 10, the parameters of the stator phase currents are formed depending on the signals i _a and i _p , the parameters of the rotor circuit of the motor and the speed of rotation of its rotor.

In the proposed embodiment, i _p = const, therefore, Figs. 1-4 do not show the relationship f _c with the first program-setting unit 17. In this mode of operation of the proposed system, the role of f _c is secondary. Thus, in the proposed system, the required frequencies and phases of the stator currents will be automatically corrected regardless of the state of the rotor circuit parameters. Therefore, the engine moment M will be determined by the signals i _a and i _p . This achieves the expansion of the range of self-tuning of the gyrostabilizer control system, in which the moment of inertia is a variable. At the same time, it is possible to regulate the moment of inertia of the flywheel, which allows to reduce energy losses during the accumulation and release of energy to them, i.e. it is possible to increase the efficiency of the system as a whole. This reduces the instability of the speed and torque of the engine when changing the supply voltage and ambient temperature. The degree of functional connections for each control channel can be separately established both before the control system is included in the operation, and directly during processing, for example, of each "step" of program-setting actions. The above-described capabilities in many practically important cases of programmed control of electric drives of satellite gyro stabilizers from the point of view of simplifying the tuning process and optimizing control modes (transient smoothness during start-up by reducing the intensity of electromagnetic processes) distinguish the proposed control system from well-known technical solutions.

Claims (1)

The adaptive gyrostabilizer control system includes a first input transformer, a thyristor switch unit, a controlled rectifier, a first DC voltage filter, an autonomous inverter, an uncontrolled reverse current inverter unit, a second DC voltage filter, a reverse inverter and a second input transformer, the input of which is combined with the input of the first the input transformer and the input of the charging unit of the switching capacitors of the autonomous inverter and is connected to the network, controlling the input input of the thyristor switch unit is connected to the output of the control channel, which contains phase voltage and current sensors, a current-voltage converter, normalizing devices connected to the corresponding inputs of the summing amplifier, the output of which is connected to the signal input of the functional converter, an inverting amplifier , a linear key, a trigger, differentiating circuits, a pulse shaper, made in the form of a single vibrator, to the clock input of the trigger of each control channel under The frequency of the mains voltage changes, the control or counting input of each trigger of each control channel is combined with the control input of the linear key and connected to the output of the relay element with an adjustable hysteresis loop, the input of which is combined with the input of the controlled quantizer and connected to the output of the adder, the first input of which is combined with the input of the timing circuit and is connected to the output of the second block of program-setting actions, the second input of the adder is connected to the speed sensor of the asynchronous motor For a flywheel, the stator windings of which are connected to the output of an autonomous inverter, the control input of which is connected to the output of the control unit by an autonomous inverter, the signal input of which is connected to the first output of the control unit, the second output of which is connected to the signal input of the rectifier control unit, the output of which is connected to the control input controlled rectifier, the control input of the reverse inverter is connected to the output of the control unit of the reverse inverter, while the power supply of the control units of the rectifier, an autonomous and reverse inverter is carried out from one power supply connected to the network, and the operation of these control units is synchronized from the mains voltage, the signal input of the control unit is connected through the comparison circuit to the output of the first block of program-setting actions, the second input of the comparison circuit is connected to the feedback sensor voltage or EMF of the flywheel induction motor, the output of the charging unit of the switching capacitors of the autonomous inverter is connected to the second signal input of the auto there is a lot of inverter, the output of the timing circuit is connected to the reset input of the controlled quantizer, the control inputs of which are connected through the frequency multiplier to the output of the clock master, the output of the controlled quantizer is connected to the first input of the functional converter of each control channel, the second input of the functional converter of each control channel is connected through inverting amplifier with controlled quantizer output.

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