CN1514207A - Magneto-optical Encoder Applied in Servo System - Google Patents

Abstract

The invention discloses a rotary position encoder—a magneto-optical encoder applied to a servo system. It includes photoelectric absolute encoder (1), DSP processor (2), controller power supply (5), it also includes addition and subtraction counter (3), magnetic sensing unit (4), battery (6), diode (D1) and diode (D2), the negative pole of diode (D1) connects the negative pole of diode (D2), the positive pole power supply terminal of addition and subtraction counter (3) and the positive pole power supply terminal of magnetic sensing unit (4), when battery power supply, The photoelectric absolute encoder does not work, and the motor rotation detected by the magnetic sensing unit is recorded in the addition and subtraction counter. The permanent magnet of the magnetic sensing unit does not need to be energized, and the circuit structure is simple, so the power consumption is small. The invention has the advantages of reasonable design, reliable operation and wide applicability.

Description

Magneto-optical Encoder Applied in Servo System

Technical Field: The present invention relates to a rotary position encoder, which is used in various devices that require rotary position detection, such as motor servo systems.

Background technology: Absolute photoelectric encoders are widely used in electric servo systems as position feedback components. It has high precision, small inertia and good stability. It can directly output absolute position information in digital form. The connection with the control unit is simple and convenient. It has become the mainstream position feedback component used in small and medium power servo systems. In the servo system, the encoder is powered by the battery when the controller has no power, and detects and records the change of the rotor position of the motor when the system controller is not working. Since the encoder uses the same photoelectric detection mechanism when it is powered by a power supply or a battery, the problem of doing so is that the battery consumes a lot of power, the replacement cycle is short, and frequent replacement is troublesome. Further analysis found that the power consumption of the encoder when it is powered by the battery is partly used for the encoder processing circuit and partly used for the light emitting element. There is not much room for reduction in power consumption of the circuit part. As for the amount of electricity used for the light-emitting element to emit light (usually ten to several hundred mw), if other methods can be used to achieve it, the light-emitting element can not emit light when the battery is powered to reduce power consumption. In fact, the position detection when the battery is powered does not need to be very accurate. In principle, it is only necessary to record the number of turns and the direction of rotation. Detailed position information can be read out by photoelectric absolute encoder after power on. Based on this understanding, a simple magnetic sensing unit can be used as a position detection mechanism when powered by a battery.

Summary of the invention: In order to overcome the defect of the prior art encoders that require frequent battery replacement due to high power consumption when powered by batteries, an encoder that can reduce power consumption when powered by batteries is provided. The present invention is achieved through the following scheme, a magneto-optical encoder applied to a servo system, which includes a photoelectric absolute encoder 1, a DSP processor 2, a controller power supply 5, and it also includes an addition and subtraction counter 3 , magnetic sensing unit 4, battery 6, diode D1 and diode D2, the positive output terminal of the controller power supply 5 is connected to the positive power supply terminal of the photoelectric absolute encoder 1 and the positive pole of the diode D1, and the negative power supply of the controller power supply 5 The terminal is grounded, the negative power supply terminal of the photoelectric absolute encoder 1 is grounded, the output port of the photoelectric absolute encoder 1 is connected to an input port of the DSP processor 2, the negative pole of the diode D1 is connected to the negative pole of the diode D2, and the positive pole of the addition and subtraction counter 3 The positive power supply terminal of the power supply terminal and the magnetic sensing unit 4, the negative power supply terminal of the addition and subtraction counter 3 is grounded, the output port of the addition and subtraction counter 3 is connected to another input port of the DSP processor 2, and the negative power supply terminal of the magnetic sensing unit 4 Grounded, the output port of the magnetic sensing unit 4 is connected to the input port of the up-down counter 3, the anode of the diode D2 is connected to the positive pole of the battery 6, and the negative pole of the battery 6 is grounded. When the controller is powered by the power supply, the photoelectric absolute encoder is powered by the power supply; since the power supply voltage is higher than the battery voltage, the addition and subtraction counter and the magnetic sensing unit are powered by the power supply through the diode D1, and the battery does not work. The DSP processor reads out the count value of the up-down counter to determine the rotation of the motor during battery power supply, and then clears the up-down counter. When the battery is powered, the addition and subtraction counter and the magnetic sensing unit are powered by the battery through the diode D2, and the photoelectric absolute encoder does not work, which reduces energy consumption. The motor rotation detected by the magnetic sensing unit is recorded in the addition and subtraction counter. The advantage of using a magnetic sensing unit is that the permanent magnet does not need to be energized, and because the functions to be realized are simple, and the corresponding circuit structure is also simple, so the power consumption is small, and the service time of the battery is significantly extended, so it does not need to be replaced frequently. The invention has the advantages of reasonable design, reliable operation and wide applicability.

Description of drawings: Fig. 1 is a schematic structural view of the present invention, Fig. 2 is a schematic structural view of a magnetic sensing unit of the present invention connected with an addition and subtraction counter and a DSP processor, and Fig. 3 is a magnetic sensitive chip 4-1 and a magnetic sensitive chip 4 -2 Schematic diagram of the waveform and phase comparison of the output voltage signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: The present invention will be specifically described below in conjunction with FIG. 1 and FIG. 2 . It consists of photoelectric absolute encoder 1, DSP processor 2, controller power supply 5, addition and subtraction counter 3, magnetic sensing unit 4, battery 6, diode D1 and diode D2, the positive output terminal of controller power supply 5 Connect the positive power supply terminal of photoelectric absolute encoder 1 and the positive pole of diode D1, the negative power supply terminal of controller power supply 5 is grounded, the negative power supply terminal of photoelectric absolute encoder 1 is grounded, and the output port of photoelectric absolute encoder 1 is connected to An input port of the DSP processor 2, the negative pole of the diode D1 is connected to the negative pole of the diode D2, the positive power supply terminal of the addition and subtraction counter 3 and the positive power supply terminal of the magnetic sensing unit 4, the negative power supply terminal of the addition and subtraction counter 3 is grounded, and the addition and subtraction The output port of the counter 3 is connected to another input port of the DSP processor 2, the negative power supply terminal of the magnetic sensing unit 4 is grounded, the output port of the magnetic sensing unit 4 is connected to the input port of the addition and subtraction counter 3, and the positive pole of the diode D2 is connected to the battery 6 positive pole, the negative pole of battery 6 is grounded. The magnetic sensing unit 4 is composed of a magnetic sensitive chip 4-1, a magnetic sensitive chip 4-2, a signal amplification circuit 4-3, a voltage zero-crossing comparison circuit 4-4, a rotation direction determination circuit 4-5 and a permanent magnet 4-6 , the rim of the disc-shaped permanent magnet 4-6 is polarized into two opposite four poles, the entire circumference of the permanent magnet 4-6 is defined as an electrical angle of 720 degrees, and the adjacent permanent magnets 4-6 There is an electrical angle of 180 degrees between the N pole and the S pole, the permanent magnet 4-6 is fixed on the motor shaft 7 of the servo system and rotates coaxially with the motor, and the magnetic sensitive chip 4-1 and the magnetic sensitive chip 4-2 are arranged on At the position opposite to the rim of the permanent magnet 4-6, the installation positions of the magnetic-sensitive chip 4-1 and the magnetic-sensitive chip 4-2 differ by an electrical angle of 45 degrees on the circumference of the permanent magnet 4-6, and the magnetic-sensitive chip 4-1 The output end of the signal amplification circuit is connected to an input end of the signal amplification circuit 4-3, the output end of the magnetic sensitive chip 4-2 is connected to the other input end of the signal amplification circuit 4-3, and an output end of the signal amplification circuit 4-3 is connected to the overvoltage One input terminal of the zero comparison circuit 4-4, the other output terminal of the signal amplification circuit 4-3 is connected to the other input terminal of the voltage zero-crossing comparison circuit 4-4, and an output terminal of the voltage zero-crossing comparison circuit 4-4 is connected to An input end of the direction of rotation determination circuit 4-5 and an input end of the addition and subtraction counter 3, another output end of the voltage zero-crossing comparison circuit 4-4 is connected with another input end of the direction of rotation determination circuit 4-5 and the addition and subtraction counter 3. Another input end of counter 3, an output end of rotation direction determination circuit 4-5 connects another input end of addition and subtraction counter 3, another output end of rotation direction determination circuit 4-5 connects an input of DSP processor 2 end. As shown in FIG. 3 , by comparing the voltage signals detected by the magnetic sensitive chips 4 - 1 and 4 - 2 at zero crossings, the direction of rotation and the number of revolutions of the motor shaft can be determined. The models of the magnetic sensitive chips 4-1 and 4-2 are both HMC1501 or HMC1512.

Claims (2)

1. A magneto-optical encoder applied to a servo system, which comprises a photoelectric absolute encoder (1), a DSP processor (2), a controller power supply (5), is characterized in that it also includes an add-subtract counter ( 3), magnetic sensing unit (4), battery (6), diode (D1) and diode (D2), the positive output terminal of the controller power supply (5) is connected to the positive power supply terminal of the photoelectric absolute encoder (1) and the anode of the diode (D1), the negative power supply terminal of the controller power supply (5) is grounded, the negative power supply terminal of the photoelectric absolute encoder (1) is grounded, and the output port of the photoelectric absolute encoder (1) is connected to the DSP processor An input port of (2), the negative pole of diode (D1) connects the negative pole of diode (D2), the positive pole power supply end of add-subtract counter (3) and the positive pole power supply terminal of magnetic sensing unit (4), add-subtract counter (3) ) of the negative power supply terminal is grounded, the output port of the addition and subtraction counter (3) is connected to another input port of the DSP processor (2), the negative power supply terminal of the magnetic sensing unit (4) is grounded, and the magnetic sensing unit (4) The output port is connected to the input port of the addition and subtraction counter (3), the positive pole of the diode (D2) is connected to the positive pole of the battery (6), and the negative pole of the battery (6) is grounded. 2. The magneto-optical encoder applied to a servo system according to claim 1, characterized in that the magnetic sensing unit (4) consists of a magnetically sensitive chip (4-1), a magnetically sensitive chip (4-2), a signal amplifier Circuit (4-3), voltage zero-crossing comparison circuit (4-4), rotation direction determination circuit (4-5) and permanent magnet (4-6), the wheel of the disc-shaped permanent magnet (4-6) The edge is polarized into two opposite four poles, the entire circumference of the permanent magnet (4-6) is defined as 720 degrees electrical angle, between the adjacent N poles and S poles on the permanent magnets (4-6) The electrical angle is 180 degrees, the permanent magnet (4-6) is fixed on the motor shaft (7) of the servo system and rotates coaxially with the motor, the magnetic sensitive chip (4-1) and the magnetic sensitive chip (4-2) are arranged on With the relative position of the rim of the permanent magnet (4-6), the mounting position of the magnetic sensitive chip (4-1) and the magnetic sensitive chip (4-2) differs by 45 degrees on the circumference of the permanent magnet (4-6). Angle, the output end of the magnetic sensitive chip (4-1) is connected to an input end of the signal amplifying circuit (4-3), and the output end of the magnetic sensitive chip (4-2) is connected to another of the signal amplifying circuit (4-3). Input terminal, an output terminal of the signal amplifying circuit (4-3) is connected with an input terminal of the voltage zero-crossing comparator circuit (4-4), and the other output terminal of the signal amplifying circuit (4-3) is connected with the voltage zero-crossing comparator circuit Another input end of (4-4), an output end of voltage zero-crossing comparison circuit (4-4) connects an input end of rotation direction determination circuit (4-5) and an input end of add-subtract counter (3) , another output terminal of the voltage zero-crossing comparison circuit (4-4) is connected with another input terminal of the rotation direction determination circuit (4-5) and another input terminal of the add-subtraction counter (3), and the rotation direction determination circuit (4 One output end of -5) is connected to another input end of the addition and subtraction counter (3), and the other output end of the rotation direction determination circuit (4-5) is connected to an input end of the DSP processor (2).

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