RU2393952C1 - Device to increase turning precision - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: proposed device comprises cutting tool depth travel drive, cutting tool depth travel transducer, spindle turn angle transducer, cutting tool lengthwise travel transducer, workpiece angular speed transducer, workpiece shape setting unit connected via first input of first adder with electric drive input, second and third adders, first, second, third, fourth, and fifth buffer registers, memory device. Note here that turn angle transducer output is connected with low-order digits of the shape setting unit input, lengthwise travel transducer output is connected with high-order digits of the shape setting unit input, shape setting unit input is connected with the first buffer register input, and, at the same time, via first input of third adder it is connected with third buffer register input. Outputs of first and third buffer registers are connected to address input of memory unit that can write in by correcting signal addresses. Data bus of memory unit is connected with the inputs of second, fourth buffer registers and output of fifth buffer register with its input connected to first input of second adder, output of second buffer register is connected to second input of first adder, while angular speed transducer output is connected with second input of third adder. To reduce random affects on learning system, it incorporates fourth adder, sixth, seventh buffer registers, error signal modulus computation unit, comparator and computing device. Note here that first input of fourth adder is connected to output of shape setting unit, second input of fourth adder is connected to cutting tool depth travel transducer output, output of fourth adder is connected with inputs of sixth buffer register, error signal modulus computation unit and computing device that can generate error signal mean-square-root magnitude at its output, output of sixth buffer register is connected to second adder second output, output of error signal modulus computation unit is connected with first input of comparator, output of seventh buffer register I connected with second input of comparator, output of computing device is connected to input of seventh buffer register, while comparator output is connected with control input of sixth buffer register.

EFFECT: higher precision of turning.

1 dwg

Description

The proposed device relates to electromechanics and can be used to improve the accuracy of turning serial non-circular parts.

A device in the form of a two-channel electric drive is known, intended for precise control of the position of mechanisms when practicing cyclic influences, including during turning of non-circular parts, when the cycle time is equal to the time of one revolution of the part (RF Patent No. 2223592, 02/10/2004, bull. No. 4) . The device uses the principle of self-training, which allows for the processing of parts with constant non-circularity in length to reduce the cyclic (from revolution to revolution) component of the shape error to a minimum value.

The known device has disadvantages. If the specified non-circularity varies along the length of the part, then when using this device, the accuracy of the implementation of the given shape is impaired. The same result in mass production is also brought about by systematic, from part to part, impact on the cutting tool from the side of the part at the time of insertion during intermittent turning.

Also known is a device for improving the accuracy of turning non-circular parts, RF patent No. 2293010, publ. BIPM No. 4, 02/10/2007 (prototype), comprising an electric drive for moving the cutting tool in the direction of cutting depth, a sensor for moving the cutting tool in the direction of cutting depth, a sensor for the angle of rotation of the spindle, a sensor for longitudinal movement of the cutting tool, a sensor for the angular speed of rotation of the part, a shape setting unit parts connected in series through the first input of the first adder with the input of the electric drive moving the cutting tool in the direction of the depth of cut, second, third adders, first, second, tert the fourth, fifth buffer registers, a storage device. In this case, the output of the spindle angle sensor is connected to the lower bits of the input of the part shape setting block, the output of the cutting tool longitudinal movement sensor is connected to the higher bits of the input of the part shape set block, the input of the part shape setting block is connected to the input of the first buffer register and simultaneously through the first input of the third the adder with the input of the third buffer register, the outputs of the first and third buffer registers are connected to the address input of the storage device, the data bus of which is simultaneously with connected to the inputs of the second, fourth buffer registers and the output of the fifth buffer register, the input of which is connected to the output of the second adder, the output of the part shape setting unit, the output of the cutting tool moving sensor in the direction of cutting depth and the output of the fourth buffer register are connected to the first, second, third inputs the second adder, respectively, the output of the second buffer register is connected to the second input of the first adder, and the output of the angular velocity sensor of the part is connected to the second input of the third th adder.

This device is designed for turning serial non-circular parts such as pistons, cams, parts with holes, longitudinal grooves and other parts that are characterized by intermittent turning. The device is based on the principle of self-training, which, when fulfilling the stability conditions of the system, minimizes systematic errors, repeated from part to part, errors determined by a given shape, intermittent turning sections from part to part, and other systematic influences.

The disadvantage of this device is its susceptibility to random influences of a different nature, not repeating from part to part. Accidental impacts on the cutting tool from the workpiece during the passage of shells in the workpiece, inclusions of foreign material, zones with variable hardness, the instability of the location of intermittent turning from part to workpiece, the error in fixing the workpiece, electrical noise in the self-learning circuit, etc. As a result, when processing the current part in the storage device, a correction signal is generated in which not only a systematic component is present, but also a component from a random error. This causes an undesirable reaction of the self-learning system to random actions that do not repeat from part to part and leads to a decrease in the accuracy of the implementation of a given shape on subsequent parts.

The technical problem solved by the invention is to reduce the influence of random influences on the self-learning system, which will increase the accuracy of turning non-circular parts. This reduction can be achieved by limiting the absolute value of the shape error signal of the workpiece involved in the formation of the correction signal for the subsequent part to a level determined, for example, by the mean square value of the shape error of the previous part.

The problem is solved in that the known device containing an electric drive for moving the cutting tool in the direction of cutting depth, a sensor for moving the cutting tool in the direction of cutting depth, a sensor for the angle of rotation of the spindle, a sensor for longitudinal movement of the cutting tool, a sensor for the angular velocity of rotation of the part, a unit for setting the shape of the part, connected in series through the first input of the first adder with the input of the electric drive moving the cutting tool in the direction of the depth of cut, the second, tr there are adders, first, second, third, fourth, fifth buffer registers, a storage device, wherein the output of the spindle angle sensor is connected to the lower bits of the input of the part shape setting unit, the output of the longitudinal movement sensor of the cutting tool is connected to the higher bits of the input of the part shape setting unit, the input of the part shape setting unit is connected to the input of the first buffer register and simultaneously through the first input of the third adder with the input of the third buffer register, the outputs of the first and third buffer res Istr are connected to the address input of a memory device configured to record the correcting signal at the addresses, the data bus of the memory device is simultaneously connected to the inputs of the second and fourth buffer registers and the output of the fifth buffer register, the input of which is connected to the output of the second adder, the output of the fourth buffer register is connected to the first input of the second adder, the output of the second buffer register is connected to the second input of the first adder, and the output of the angular velocity sensor de if connected to the second input of the third adder, it is additionally equipped with a fourth adder, sixth, seventh buffer registers, an error signal module calculation unit, a comparator, a computing device, the first input of the fourth adder connected to the output of the part shape setting unit, the second input of the fourth adder connected to the output a sensor for moving the cutting tool in the direction of the depth of cut, the output of the fourth adder is simultaneously connected to the inputs of the sixth buffer register, mode calculation unit For an error signal and a computing device configured to generate an rms value of the error signal at the output, the output of the sixth buffer register is connected to the second input of the second adder, the output of the error signal module calculation unit is connected to the first input of the comparator, the output of the seventh buffer register is connected to the second input of the comparator , the output of the computing device is connected to the input of the seventh buffer register, and the output of the comparator is connected to the control input of the sixth buffer register a.

The drawing shows a structural diagram of the proposed device. The proposed device comprises an electric drive 1 of the movement of the cutting tool 2 in the direction of the depth of cutting, a sensor 3 of the movement of the cutting tool 2 in the direction of the depth of cutting, a sensor 4 of the angle of rotation of the spindle, a sensor 6 of the longitudinal movement of the cutting tool 2, the sensor 7 of the angular velocity of rotation of the part 5, block 8 tasks the shape of the part, connected in series through the first input of the first adder 9 with the input of the electric drive 1 moving the cutting tool 2 in the direction of the depth of cut, second 10, third 11 adders, first 12th, second 13th, third 14th, fourth 15th, fifth 16th buffer registers, memory 17, and the output of the spindle angle sensor 4 is connected to the lower bits of the input of the part shape setting unit 8, the output of the longitudinal movement sensor 6 of the cutting tool 2 is connected to the older ones the input bits of the part shape setting block 8, the input of the part shape setting block 8 is connected to the input of the first buffer register 12 and simultaneously through the first input of the third adder 11 with the input of the third buffer register 14, the outputs of the first 12 and third 14 are buffer x registers connected to the address input of the storage device 17, configured to record the addresses of the correction signal, the data bus of the memory device 17 is simultaneously connected to the inputs of the second 13, fourth 15 buffer registers and the output of the fifth buffer register 16, the input of which is connected to the output of the second adder 10 , the output of the fourth buffer register 15 is connected to the first input of the second adder 10, the output of the second buffer register 13 is connected to the second input of the first adder 9, and the output of the sensor 7 is angular the rotational speed of the part is connected to the second input of the third adder 11. In addition, it is additionally equipped with a fourth adder 18, sixth 19, seventh 20 buffer registers, an error signal module calculation unit 21, a comparator 22, a computing device 23, the first input of the fourth adder 18 being connected to the output of the part shape setting unit 8, the second input of the fourth adder 18 is connected to the output of the sensor 3 for moving the cutting tool 2 in the direction of the depth of cut, the output of the fourth adder 18 is simultaneously connected to by the odes of the sixth buffer register 19, the error signal module module calculation unit 21 and the computing device 23 configured to generate an rms error signal output, the sixth buffer register output 19 is connected to the second input of the second adder 10, the output of the error signal module module calculation unit 21 is connected to the first input of the comparator 22, the output of the seventh buffer register 20 is connected to the second input of the comparator 22, the output of the computing device 23 is connected to the input of the seventh buffer register 20, and Exit of the comparator 22 is connected to a control input of the sixth buffer register 19.

The device operates as follows. The signal for specifying the shape corresponding to the drawing of the outer surface of the part is generated at the output of the block for specifying the shape of the part 8 in functional dependence on the output signals of the sensor 6 for the longitudinal movement of the cutting tool 2 and the sensor 4 for the angle of rotation of the spindle. These signals are supplied, respectively, to the upper and lower bits of the input of the unit 8 for specifying the shape of the part.

When turning the next part, the correction signal from the output of the second buffer register 13, formed in the storage device 17 when turning the previous part, is added to the output signal of the unit 8 for setting the part shape in the first adder 9. This correction signal is aimed at reducing shaping errors caused by the limited speed of the electric drive 1 moving the cutting tool 2 in the direction of the depth of cut and other reasons.

Reading the current value of the correction signal from the storage device 17 and transferring it from the data bus of the latter to the output of the second buffer register 13 occurs simultaneously with the transmission from the input of the first buffer register 12 to its output of the address space code generated by the output signals of the spindle angle sensor 4 and sensor 6 longitudinal movement of the cutting tool.

At a subsequent point in time at an address earlier than the current address, through the third buffer register 14, the data stored in the memory of the memory 17 is read and transferred from the data bus to the output of the fourth buffer register 15. The address is shifted to the earlier one on the third adder 11 , and the magnitude of the displacement is proportional to the value of the output signal of the sensor 7 of the angular velocity of rotation of the part. And, finally, at the last time interval at the above address earlier than the current address, the value of the correction signal for the subsequent part is written to the memory 17 from the output of the second adder 10 through the fifth buffer register 16. The described procedure in the form of three consecutive time intervals for controlling the elements of the structural diagram shown in the drawing is repeated at each address of the address space that describes the surface of the part in block 8 of the form.

Thus, at the end of turning the next part in the storage device 17, the values of the correction signal that will be used when turning the next part will be recorded at all addresses of the address space.

The operation of the elements included in addition, in accordance with the structural diagram of the device is as follows.

The value of the correction signal is generated at the output of the second adder 10 as the sum of the output signals of the fourth 15 and sixth 19 buffer registers. In this case, the shape error signal received at the output of the fourth adder 18 in the form of the difference of the output signals of the unit 8 for specifying the part shape and the sensor 3 for moving the cutting tool 2 in the direction of the depth of cut is transmitted from the input of the sixth buffer register 19 to its output only if there is control input enable signal.

The comparator 22 is designed so that its output signal is enable for the buffer register 19, provided that the signal at its second input exceeds the signal at the first input. In this case, the signal value at the second input of the comparator 22 is equal to the rms, for example, the value of the shape error signal generated at the output of the computing device 23 after the turning of the previous part.

If the absolute value of the error signal generated at the output of the error signal module calculation unit 21 is greater than the signal value at the second input of the comparator 22, there is no enable signal at the output of the comparator 22 and, therefore, the value of the output signal of the buffer register 19 does not change, regardless of the possible changes in the signal to it the entrance.

Thus, the sixth buffer register 19 in combination with the unit for calculating the error signal module 21 and the comparator 22, according to the scheme, performs the function of limiting the absolute value of the signal of the current shape error, and the level of limitation is determined by the mean square, for example, the value of the shape error signal generated at the output computing device 23 at the end of turning the previous part.

When turning the first part, the signals at the outputs of the second 13, fourth 15, fifth 16, sixth 19, seventh 20 buffer registers are zero and, therefore, zero values of the correcting addresses are written to the memory 17 from the output of the adder 10 at all addresses earlier than the current ones signal. When turning the second part, the signals at the output of the second 13, fourth 15 buffer registers are also equal to zero, but the values of the correction signal for the subsequent part are already written to the memory 17 at the addresses earlier than the current ones, due to the appearance of the sixth buffer register 19 at the output an error signal at the moments when a permission is supplied to its control input from the output of the comparator 22. Moreover, if the form errors have a systematic character, from detail to detail, then the proposed device works similarly to the known one (p ototip), reducing them to the workpiece from the workpiece to a minimum value.

When random errors occur during turning of the next part, the signal at the input of the sixth buffer register 19 increases, but at its output changes little due to the action of the restriction. This is due to the fact that the level of limitation of the absolute value of the error signal was determined at the end of processing the previous part and with smaller errors. Consequently, the correction signal for the next part will also change little, and if the errors do not repeat, the self-learning system will continue to work with minor errors.

Thus, in the proposed device, in comparison with the known, the influence of random influences on the system will be reduced, which will increase the accuracy of turning of non-circular parts.

Claims (1)

A device for turning non-circular parts containing an electric drive for moving the cutting tool in the direction of cutting depth, a sensor for moving the cutting tool in the direction of cutting depth, a sensor for the angle of rotation of the spindle, a sensor for longitudinal movement of the cutting tool, a sensor for the angular velocity of rotation of the part, a unit for specifying the shape of the part, connected in series through the first input of the first adder with the input of the electric drive moving the cutting tool in the direction of the depth of cut, the second, third mators, first, second, third, fourth, fifth buffer registers, a storage device, wherein the output of the spindle angle sensor is connected to the lower bits of the input of the part shape setting unit, the output of the longitudinal movement sensor of the cutting tool is connected to the higher bits of the input of the part shape setting block, input the part shape task unit is connected to the input of the first buffer register and simultaneously through the first input of the third adder with the input of the third buffer register, the outputs of the first and third buffer register connected to the address input of the storage device, capable of recording the addresses of the correction signal, the data bus of the memory device is simultaneously connected to the inputs of the second, fourth buffer registers and the output of the fifth buffer register, the input of which is connected to the output of the second adder, the output of the fourth buffer register is connected to the first the input of the second adder, the output of the second buffer register is connected to the second input of the first adder, and the output of the angular velocity sensor of the part with is single with the second input of the third adder, characterized in that it is equipped with a fourth adder, sixth, seventh buffer registers, an error signal module calculation unit, a comparator, a computing device, the first input of the fourth adder connected to the output of the part shape setting unit, the second input of the fourth adder connected to the output of the cutting tool displacement sensor in the direction of the cutting depth, the output of the fourth adder is simultaneously connected to the inputs of the sixth buffer register, the calculation unit an error signal module and a computing device configured to generate an rms value of the error signal at the output, the output of the sixth buffer register is connected to the second input of the second adder, the output of the error signal module calculation unit is connected to the first input of the comparator, the output of the seventh buffer register is connected to the second input of the comparator , the output of the computing device is connected to the input of the seventh buffer register, and the output of the comparator is connected to the control input of the sixth buffer register Istria.

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