SU473272A1 - Device for controlling a stepper motor - Google Patents

Description

one

The known devices for controlling a stepper motor, comprising a switch, the input of which is connected to the outputs of two differentiating circuits connected to the "NOT, OR" logic elements and two matching circuits connected to the inputs of the "OR" element, have limited functionality and do not allow be the switching system of a stepper motor.

In the proposed device, for the purpose of expanding the functionality, a switching system sensor is installed, the outputs of which are connected to the same inputs of both coincidence circuits connected by their second inputs to the communication system command buses, and the third inputs of the coincidence circuits are interconnected and connected to one of the inputs differentiating circuits.

FIG. 1 shows a diagram of the described device with reference to a four-phase stepper motor; in fig. 2 shows timing diagrams illustrating the operation of the circuit.

A device for controlling a stepper motor contains coincidence circuits 1 and 2, one of the inputs of which is connected to the ground.

Tines I and II of the task of the switching system, logical elements "OR 3 and" NOT 4, differentiating the circuits 5, 6 and the switch 7 of the windings 8 of the stepping motor, including

The pulse distributor 9, the sensor of the switching system 10 and the threshold device 11. The threshold device in turn contains transistors 12 and 13, stabilizer 14 and resistors 15-20.

The proposed device works as follows.

As applied to FIG. 1, in a circuit for controlling a four-phase stepper motor, the pulse distributor 9 impregnates the eight-stroke asymmetrical switching of the control windings 8 of the stepper motor. The drop in voltage across the impedance resistor 10 is determined by the current flowing in the common wire of the control windings 8 and depends on the number of simultaneously connected windings, i.e., on the switching system.

The signal from resistor 10 is applied to one of

shoulders of the differential cascade of the threshold device 11. assembled on transistors 12. 13 and resistors 16, 17, 18. The other shoulder of the differential cascade is connected to a stable voltage divider formed on resistors 15, 19, 20 and zener diode 14. Voltage drop on resistor 10 is selected from the condition af / i

1 I io,

; Dap where ipdeks I means mode when

under current there is one motor winding, index II - when the current consumes two windings. When the voltage drops across the resistor

10, equal to ALi, the voltage across the base of transistor 12 is more positive than that of transistor 13, and the cascade current, determined by the resistance of resistor 18, passes through the right arm. In this case, on the resistor 17, the QW is the output signal corresponding to the alternate switching (simultaneous switching on of one winding of the stepping motor). Connecting two rev | Motor 8 to power supply U opens transistor 13 and the signal corresponding to such a switching system is allocated to resistor 16. Eight-m-ity of the unbalanced switching of windings 8 of a stepping motor corresponds to alternating switching of transistors 12 and 13 at every step.

In the absence of signals at the inputs of the switching system (inputs I and II in Fig. 1), the control pulses in diagram A (Fig. 2) are looped onto the bar. The input is supplied to the distributor 9 of the switch 7 through the differentiating target 6. The motor windings switch at the same time (for the eight-stroke system, i.e., for each control impulse, the engine runs a cdag equal to half of the main one. Diagram D (Fig. 2) shows the voltage on resistor 10, and pa diagrams D and E, respectively, the voltage on the collectors transistors 12 and 13.

If the bus I (alternating four-stroke switching) or bus II (paired four-stroke switching) is given a signal according to diagrams B or C, then the device will automatically determine the switching on time of the specified switching system using feedback from the sensor of the switching system. For example, if the number of simultaneously switched on engine phases at the moment of issuing a command to input I or II corresponded to one of the positions in this switching system, the switch goes immediately to the desired mode. If the state of the included windings did not correspond to the required switching system, then iB to the previous switching system will be completed one more step.

After the occurrence, on one of the coincidence circuits, I or 2 of the switching system set signal and the feedback signal controlled 1 o, the pulses passed through circuit 1 (chart W in Fig. 2) or circuit 2 (diagram 3) and further through circuits "OR 3" NOT 4 and differentiating circuit 5 (diagram AND in FIG. 2) at the input of the distributor 9, where simultaneously pulses come from differentiating circuit 6 (diagram K),

Ooraz nosledovatslnost) packs of two I.muls (diagram L).

The duration nmpu-ls. 11 (diagram L) is chosen such that the frequency of following the double pulses in the batch (diagram E) would ensure the switching of the transistors of the output channels of the pulse distributor, but would not be sufficient for the engine to be operated by the engine.

Thus, the distributor commutates over the eight-stroke circuit, and the time between the double pulses in the packet is chosen so small that the current in the winding 8 does not have time to rise to a value that can create a moment to turn the motor on the corresponding eight-stroke system to: 1 m. . As a result, the engine responds only to the second of the impulses in the pack, and the given four-stroke switching system takes place. The engine thus fulfills the main step. After the disappearance of the signals at inputs I and II of the commutator, it proceeds to eight-clock commutation.

The description of the operation of the device is given for a four-phase shchagovogo engine, however, the nature of the operation of the engine and the principle of construction of the device does not change even with an arbitrary number of phases.

In the transition from 2 P-stroke to w-stroke switching system, due to ambiguity in the general case of normal conditions, the engine can work out the first step in the previous switching system. However, information taken from the sensor of the switching system can be used in the control software to compensate for the error. Kpo.v, this error can be eliminated if the calibrated pulse series with a certain number of pulses in a series are used for control. Paprimer, when the engine is alternately operating on four-stroke and eight-stroke commutation, the number of imulses worked out via the eight-stroke switching system is limited, namely, if the same four stroke was used before and after the eight-stroke commutation, the number of pulses must be even if however, an eight-stroke commutation is performed between different types of four-stroke, then the number of pulses is not TCJi baking.

The subject is invented and

A device for controlling a stepper motor, comprising a switch, the input of which is connected to the outputs of two differentiating circuits connected to logical elements "NOT, OR" and two coincidence circuits connected to the inputs of the element "OR, characterized in that functionality, a switching system sensor is installed, the outputs of which are connected to the same inputs of both coincidence circuits connected by their second inputs to the task buses

switching systems, and the third inputs of the mentioned circuits coincide and are connected to the input of one pi of the replication circuits.

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