SU859078A1 - Apparatus for contactless monitoring of position,speed and acceleration of moving frame of resistance butt welding machine - Google Patents

Description

The operation of all units is controlled by the signals of the control unit supplied to the corresponding inputs of each unit, and the input of the control unit is connected to the third output of the voltage transformer 3.

A disadvantage of the known device is the non-linear nature of the static dependence of the position of the movable frame on the difference in magnetic inductions measured at two stationary points, and the dependence of the performance on the brand and size of the welded strips, which leads to poor measurement accuracy and as a result, deterioration in welding quality.

The purpose of the invention is to improve the accuracy of control, by eliminating the dependence of the device readings on the current value.

The goal is achieved by dividing and logarithmizing blocks, the integrator's outputs are connected to the dividing unit, and its output is connected to the input of the logarithmic unit, the output of which is connected to the first Of the two series-connected differential elements, and the control input of the logarithmic unit with the output of the control unit. Fig. 1 shows a block diagram of a device for controlling position, speed and "acceleration;" in fig. 2 - location of magnetic field transducers, Hall sensors on the fixed bed tire and the distribution of the power lines of the magnetic induction vectors ..

The device contains two magnetic field transducers 1 and 2 (for example, Hall sensors) located on either side of the fixed-bed tire, a voltage transformer 3, integrators 4 AND 5, dividing unit 6, logarithm unit 7, differentiating elements 8 and 9, and a unit 10 controls, with converters 1 and 2 connected to the first and second. the outputs of the voltage transformer 3 connected to the jaws of the butt-welding machine, the outputs of the converters are connected to the corresponding HiHTejpa frames 4 and 5, the outputs of which are connected to the dividing unit 6, its output is connected to the logarithmic unit 7. In series with which two differentiating elements 8 and 9 are connected, control inputs of the rhyming log unit and differentiating elements are connected to the outputs of control unit 10, the input of which is connected to the third output of the voltage transformer, the power lines of the vector magitite induction fields formed by the busbar moving bus and a stationary bed intersect two transducers of the same name (Fig. 2) Moreover, in each half-period in the transducer located between the tires, the magnetic induction vectors are based on the principle of supere zitsii fields are added and in the other converter - are subtracted. The device works as follows.

When a moving-bed busbar moves, the density of the magnetic field lines of force increases as it approaches the stationary,; therefore, the B-Bn field affects the converter 1 and the 2 - field acts on the converter 1. In view of the fact -; that the transducers are connected to a voltage transformer, the primary winding of which is connected to the jaws of the butt welding machine, from the output of transducers 1 and 2 receive different signals defined by the expressions for identical Hall sensors;

 (B.-V- ,,, e, y (& - v8a,),

where and (}. Hall EMF, nponopi- tial to power, is the sensitivity of Hall sensors;

1U control current flowing through the plate of the Hall and when interacting with a magnetic field stimulates the EMF of the Hall (the control current is proportional to the voltage removed from the jaws of the sealer)

Magnetic induction vectors are proportional to the welding current, therefore

 and, 1cv / (2) where K is const;

Cg f (S) depends on the location of the current-carrying ishna of the moving frame.

Then expression (1) will be rewritten as

e riyice ((S))

(3)

and r riylce ((S))

These instantaneous values of the signals are sent to the corresponding integrators 4 and 5. The need for integration is due to the fact that the welding process is accompanied by pulsations caused by explosions of metal bridges, and therefore, obviously, the signals from the sensor are also. are pulsating and need to be integrated. Integration takes place in a half-period of industrial frequency or in a time interval that is a multiple of it. Those. expressions (3) will be rewritten as

t.

)) 4y3c6ai

eight

I

hi

Q

Claims (1)

Claim A non-contact control device for the position, speed and acceleration of the movable bed of a flash butt welding machine, containing two magnetic field transducers located on both sides of the busbar of the fixed bed, a voltage transformer whose primary windings are connected to the jaws of the machine, and the secondary to two integrators, sequentially connected differentiating element and a control unit, and the inputs of the magnetic field converters are connected to the first and second outputs of the transformer secondary windings voltage, and the outputs are connected to the respective integrators, the control inputs of the two differentiating elements are connected to the output of the control unit, to the input of which the third output of the voltage transformer is connected, which means that, in order to improve the accuracy of control by eliminating the dependence of the device readings on. current value, a division block and a logarithm unit 30 are introduced into the device, while the outputs of the integrators are connected to the division block, its output is connected to the input of the logarithm unit, the output of the latter is connected to the first 35 series-connected differentiating elements, and the control input of the logarithm unit is connected to the output of the control unit.