SU1414594A1 - Apparatus for adaptive control of grinding machine - Google Patents

Abstract

The invention relates to a machine tool industry and can be used in systems for stabilizing the cutting speed on grinding machines. The purpose of the invention is to improve Accuracy by making it possible to measure the time of HapactaHan EMF in the linear part of the acceleration (when the engine torque is kept 1 | stop). The device contains a grinding wheel motor with a controlled transducer. The motor circuit includes an EMF sensor and a load sensor. The output of the EMF sensor is connected to the inputs of the first and second comparators, the second inputs of which are connected to the corresponding devices of the reference voltages. One of the comparators is connected to the output of the load sensor. The outputs of the comparators are connected via a logic element with a control input of the key, closing the circuit consisting of an EMF sensor, a key, an integrator, a block of threshold elements and an adder connected in series, the output of which is connected to a drive converter of a pulley wheel. 1 nl i (L

Description

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The invention relates to a machine tool industry and is intended for use in systems for stabilizing the cutting speed on grinding machines.

The purpose of the invention is to improve the accuracy by making it possible to measure the rise time of the EMF in the linear acceleration portion (when the engine torque is kept constant).

The drawing shows the functional diagram of the device for adaptive control of the grinding machine

The device contains a controlled transducer; (1, connected to the electric motor 2 with a grinding wheel 3 fixed on its base., The EMF sensor and the load sensor 5 connected to the electric motor 2 circuit, the EMF sensor 4 is connected to the working input of the key 6 and first the inputs of comparators 7 and 8, the reference voltage adjuster 9 is connected to the second input of the comparator 7, the voltage reference adjuster 10 and the load sensor 5 are connected to the second input of comparator 8, the outputs of the comparators 7 and 8 are connected to the cooTeTCTBywuijiM inputs of the logic element 11, output which It is connected to the control key input 6, the integrator 12, block 13 threshold elements, adder 14 are connected in series to the output, KoTopoi o is also connected to the input device 15 of the angular velocity of grinding Kpyj a, the cyNfMaTopa 14 output is connected to the controlled converter 1,

The device works as follows.

For starting the electric motor 2 with the grinding wheel 3 fixed on its shaft, the controlled converter 1 is turned on.

Simultaneously with the start of acceleration, the voltage U appears at the output of sensor 4 PDS. Until the voltage value and from sensor 4 EMF reaches the voltage level U, set by setpoint 9, a logical signal O is present at the output of the comparator, at the output of the comparator 8 and logical element 11 - logical 1, key 6 is open, the output voltage AND 1 of the integrator 12 is zero. As the engine accelerates, the voltage U at the upstream of the 4-emf sensor increases, and when it reaches the U value,

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at the output of the comparator 7 in: 1 logical 1. This results in the appearance at the output of the logic element 11 of the logical signal O, the closure of the switch 6 and the connection of the voltage and the sensor 4 of the EMF to the input of the integrator 12.

The voltage U at the output of the integrator 12 begins to increase and reaches the value at which one of the elements of the block 13 threshold elements is triggered and at its output a signal JU arrives, the input to the sum, torus 14, the number of threshold elements is equal to the number of approximated nonlinear parts dependencies / 1U f (tp). When one of the elements of the block 13 threshold elements is triggered, the output signal is its maximum, corresponding to the maximum possible wear of the LU-grinding wheel. This signal / 5 is summed with the reference signal Ui in the adder 14 and goes to the controlled converter 1.

The additional signal U does not affect the starting process of the electric motor, since the automatic control system of the converter 1 operates to maintain the starting torque of the motor 2. The start continues and the voltage at the outputs of the EMF sensor 4 and the integrator 12 increases, and at the output block 13 of the threshold elements is reduced.

When the voltage at the output of the EMF sensor 4 reaches U ,, equal to the reference voltage of the comparator 8, set by the reference voltage adjuster 10, the comparator is activated, a logic signal O appears at its output, and the logic output 1 appears at the output of logic element 11 This leads to the opening of key 6 and the termination of integration.

At the output of the integrator 12, a voltage is stored corresponding to the time Cp of the EMF rise from the value and to the value U7. This time corresponds to the acceleration time of the motor 2 from the speed

CO, up to speed

CO, since with sufficient accuracy for engineering purposes it is possible to consider the emf of motor-atell proportional to the rotation frequency. When the grinding wheel is not worn, the signal jL) on integrator 12 is maximum, and at the output of block 13 the threshold of new elements is minimal and zero, acceleration of the drive continues up to the rotation frequency determined by the ultrasonic signal of the rotation setting unit. The values of the reference voltages U and U. are selected from the linear part of the dependence 1, f (t).

When the wheel is worn out, the output of the block 13 of threshold elements contains a voltage / 1U corresponding to the wheel wear, which, summing up in the adder 14 with Uj, goes to the converter 1 and provides the acceleration of the grinding wheel 3 to an angular speed at which the cutting speed is constant. The effect of the resistance moment on the engine start is taken into account by the load sensor 5. As the resistance moment increases, the signal at the output of the load sensor 5 increases and, at the input to the comparator 8, decreases the reference voltage U.

Claims (1)

Invention Formula Device for adaptive control of the grinding machine, containing 0 motor (caliper wheel with controlled transducer, motor EMF sensor connected in series, key, integrator, block of threshold elements and adder, the output of which is connected to a thyristor converter, and the second input with an angular velocity adjuster, motor load sensor, first adjuster the reference voltage, the output of which is connected to the first comparator, while the inputs of the comparator are also connected to the outputs of the EMF sensor 5 and a load sensor, characterized in that, in order to improve the accuracy, a second reference voltage setting unit, the second 0 a comparator and an NAND logic element, the output of which is connected to the control input of the key, the input of the second comparator is also connected to the output of the EMF sensor, and the second input of the NAND logic element is connected to the top5 home of the first comparator.