SU568938A1 - Circuit system of program control - Google Patents

Description

displacement, connected to the displacement-voltage converter, and the second comparison unit, one of the inputs to which is connected via a memory unit to the program input device, and the output of the second comparison unit is connected to the input of the control device 3.

The disadvantages of such a system are limiting the accuracy of tracking movements as a result of the detection of feed errors based on speed deviations determined by a digital tachometer, without regard to travel errors, the feed rate control system does not generate pulses to compensate for movement errors, but only allows the formation of pulses. commands with a negative error block content, the feed speed of each axis axis is controlled by accelerating or slowing the feed rate on all axes of coordinates simultaneously. The system needs an interpolator, which complicates the system and reduces its reliability.

The aim of the invention is to improve the accuracy and reliability of the contour program control system.

The goal is achieved by introducing a functional converter into the system, the input of which is connected to the program input device, the first inverter and the first switch, the switch and the second inverter in series, and the third and fourth comparison blocks and the second adder connected to the functional converter and each coordinate the unit of speed, the output of the second adder for each coordinate through. successively connected the first unit of comparison and the third unit of comparison, connected to the device speed control of this coordinate is connected to the control unit of the executive body, and the output of the second adder is connected to the input of the fourth comparison unit connected to the converter "displacement-voltage of this coordinate, the input of the first adder and the output of the second inverter are connected respectively to the output of the fourth and third blocks comparison of one coordinate, and the switch output and the input of the first inverter are connected respectively to the output of the fourth and the input of the third comparison block to the other ordinate, the output control device is connected to the inputs of a functional transducer, the setpoint speed for each coordinate and - to the inputs of the block of memory, speed adjusting device and the fixing device.

In the drawing, a block diagram of a two-coordinate software control loop contouring system is presented, which contains executive bodies 1 and 2, blocks 3 and 4 of the control and a completing organ, speed master 5, functional converter b, third comparison blocks 7 and 8, speed sensors 9 and 10 , And and 12 motion sensors, control device 13, switch 14, locking devices 15 and 16, second comparison blocks 17 and 18, memory blocks 19 and 20, control device connections 21 to system blocks, speed control devices 22 and 23, second the sum tori 24 and 25, displacement-voltage converters 26 and 27, fourth comparison blocks 28 and 29, first adder 30, first inverter 31, second inverter 32, first comparison blocks 33 and 34, program input device 35.

The system works as follows. In the case of straight-line trajectory movements of the machine's executive body, along the coordinate axes, the control current can be fed into the control channels both simultaneously and separately. The speed of movement of the executive bodies 1 and 2, for example two

Hydraulic motors, in orthogonal coordinate directions, are controlled by control units 3, 4 of actuators, for example, controlled throttles of hydraulic systems, driven by direct current electric drives, the parameters of which are controlled by a speed controller 5, receiving commands from the control unit

13 to the corresponding change in control voltage. In the course of the propagation of linear trajectory displacements of the feedback circuit of the senders 11 and 12 are separated by the switch

14 and the parameters of the control current supplied by the speed limiter 5 to the control units 3 and 4 are corrected only by the speed sensors 9 and 10, for example, the fluid pressure sensors in the hydraulic systems of the hydraulic actuators. In this case, the blocks 3, 4 are fed with a current, the parameters of which are proportional to the derivative of the displacement error, i.e. proportional to the change in the velocity of the displacement, and thus stabilize the speed of the actuator in each coordinate direction. In case of separate alternate functioning of the control channels in the process of positioning the machine organs, the shift of the non-functioning executive body 1 or 2 is prevented by fixing it with fixing device 15 or 16 at the command of control device 13.

During the movement, the movement sensors And and 12 deliver the current to the second comparison units 17, 18, functionally connected with the memory blocks 19, 20.

When programming the required movements in each transition of the technological operation, the cells of the memory unit are tuned to the corresponding number of pulses that are in the process of system operation.

through the transducers contained in blocks 19, 20, are compared with those from sensor 11 or, 12. Upon transition to a balanced state, the comparison blocks 17 and 18 issue control commands to the device.

control 13, which, in turn, issues commands: setpoint 5 - de-energize the control channels; fixing devices 15, 16 - fix executive bodies 1 and 2; memory blocks 19, 20 — connect to displacement 17, 18 displacement memory cells in a subsequent transition of a technological operation; switch 14 - to divide or connect adder 30 with comparison blocks 7, 8; to device 35 - to submit the program of work of the system blocks to ochepeiHvio. Stable, but different (proportional) SPEED movements of the executive bodies when reproducing the linear trajectory movements of the machine organs inclined relative to the x, y axes. provided by the inclusion of the device 13 in the arm of the comparison unit 7 or 8 of the corresponding resistor of the speed control device 22 or 23. Control the contour movement by the commands of the control device 13 setpoint 5 and function converter 6 are connected to the power supply circuit, and switch 14 connects the feedback circuits from the sensors 11, 12 to the third comparison units. Upon command of the device 13, the speed regulating devices 22 and 23 are automatically brought to equilibrium (balance) the bridge circuits of the blocks are compared. 7 and 8, a functional ppeobrazovatel 6 is connected to adders 24, 25 and provides the change in control current according to a desired mathematical function. Blocks 7 and 8 begin to produce currents and titanium to control units 3, 4 of alternating voltage according to those FUNCTIONS that REPRODUCT Converter 6. For example, if the converter reproduces the change in current parameters in CIRCULAR sine cosine functions, then the velocity of the actuator on the X axis will be: U - UT: - sin ш /, and the speed along the axis Y: and y - UT cos wf. As a result of the addition of these speeds, the executive body of the machine will have a circle of movement path. The elliptic curves of the machine's executive body will describe if, when playing the same bunker (circular), additional resistors of devices 22 or 23 will be introduced into the shoulders of the bridge circuits of the comparison blocks 7 and 8, setting in this case the values of the major or minor axis of the ellipse. The radii of curvature of the trajectories of movement are determined by the rate of change of the control voltage supplied to the control channels by the functional converter 6, the magnitude of the velocity vector (feed speed of the actuator along this trajectory) is set by the speed adjuster 5. The length of the trajectory movements along each coordinate is limited by reference systems movements described in the above. In order to eliminate the mismatch of the speeds of the coordinate movements of the executive bodies 1 and 2, which may arise as a result of oscillations of external loads on the drives, the system is equipped with a feedback circuit of the displacement sensors I and 12 with the comparison blocks 7 and 8 through current transformers 26, 27 to the level control current, comparison units 28, 29, adder 30, inverters 31, 32 and through switch 14. In view of the fact that the parameters of the control current in each control channel are corrected by sensors 9 and 10 according to the SPEED tracking through the first Loka comparing 33 and 34, movement of the sensors 11 and 12 to give a comparison unit 28, 29 current. whose parameters are proportional to the error of movement of each executive body I and 2 and derived from this error, i.e., are proportional to changes in the speed of movement. Blocks 28, 29 compare these parameters with the parameters of the current supply to the control loops and output the signals 30 proportional to the tracking errors for each control loop. As a result of the presence in the circuit of the sensor 11 of the inverter 31, the cummator 30 generates the algebraic action of summation and generates a correction impulse through the switch 14. The use of an inverter 32 provides a pulse of opposite sign to Comparison Units 7 and 8, which improves the speed of the control system. If, as a result of external influences, the SPEED of the movement of the organ 1 decreases, respectively, the speed of the organ 2 decreases, and the executive body of the machine continues moving along the given trajectory. Thus, the proposed system, unlike the known ones, is closed in control channels. All parameters of the system functioning in each transition of the technological operation are set by the input device of the program 35. For example, an electronic computer that develops the technological process of performing the operation on the machine and sends it to the memory: from block 13 - the program of the sequence of action of all elements of the system; Blocks 19, 20 - program of displacement values: blocks 5. V. 22. 23- program of processing modes. The use of this system of control allows to increase the accuracy and extend the functionality of the control systems, automatically programming the processing of curvilinear FORM surfaces without using expensive equipment (interpolators, etc.), digital and copy control systems and significantly reduces the number of electrical and electronic equipment

in the system, improves reliability, reduces cost and overall dimensions.

Claims (3)

1. Collection “Contour systems of numerical control and their elements, M.,“ Mashinostroenie, 1972, p. 25-29. 2. US patent No. 3619582, cl. 1971 3. US patent No. 3792333, cl. 318-571, 1974