DE2137853A1 - DEVICE FOR CONTROLLING STEPPER MOTORS - Google Patents

Description

"Device for controlling stepper motors" The innovation concerns a device for controlling stepper motors, such as this z. B. on machine tools can be used to move a slide.

It is known that such controls have the disadvantage that stepper motors have a relatively low torque when starting and that from this state the motor starts up with the necessary definable step frequency. Man has already tried to carry out the start-up in several stages.

However, it is better to run up the engine in one step. Proposed a frequency increase in time-linear or e-function was added.

So far, however, an exact adjustment of the frequency increase has been made on the course of the torque characteristic curve, because the effort is too high. The same e-function was used for the acceleration and braking processes and chosen a compromise with regard to the most unfavorable load case.

However, Dias has not been satisfactory as it is currently being sought in practice stepper motors directly without the interposition of hydraulic amplifiers or the like. To connect to tools in order to save costs.

The innovation therefore suggests that the frequency increase should be adjusted to the course of the motor characteristic with regard to the motor torque in the block of the generator of the exponential function can be determined and thus the characteristics of the two-dimensional Operating condition is adaptable.

The generator can be designed so that optionally different Time constants # of the e-function are adjustable, you can e.g. use a clamping table, who is unbalanced only when a position is retracted, achieve shorter times, by choosing another #.

The time constant can also be automatically influenced from the outside, e.g. by using the existing starting torque before the start for setting by eating the load pressure at one point on the table, which yes influences the starting torque accordingly.

The innovation has the advantage of precisely adapting the characteristic data of the stepper motor to the required load case. This becomes a @ al in the movement processes Time saved and on the other hand, motors can be used for higher load elements used than this was the case.

The device is shown schematically in the attached schematic diagram shown.

In module 1, the start-up time is entered linearly from the outside. 11 Block 2, this is converted into an e-function and there e.g. manually the load case on the machine tool table 7 with regard to the time constant # regulated. The next module 3 converts voltage into frequency. In module 4 there is a ring counter for setting the direction of rotation or stop. this is followed by the amplifier 5 and then the stepping motor 6, e.g.

the machine tool table 7 moves. The number of steps of the rotor 6 is replaced by module 8, see B. a comparison counter is specified.

It is possible to use branch 9 as a time constant # Adapt automatically to the respective load in module 2. This can e.g. by taking a measured variable from the table 7, which is fed to the module 2 will.

The device can also be designed so that the building block 2 from the following block always to the maximum with regard to the time constant # is controllable. This can be done, for example, by an analog computer module that receives its values from blocks 4-8.

Claims (3)

Claims 1. Device for controlling stepper motors, d a d u r c h g e it is not indicated that the adjustment of the time constant of the frequency increase to the course of the motor characteristic curve of the motor (6) with regard to the motor torque can be defined in the module (2) of the generator of the e-function. 2. Apparatus according to claim 1, d a d-u r c h g e k e n n -z e i c h n e t that in module (2) of the generator ex the time constant # of the e-function can be controlled to the maximum in the tap from the following components. 3. Device according to claim 1 and 2, d a d u r c h g e -k e n n s e i c h n e t that the time constant # can be influenced from outside.