How to calculate the acceleration frequency of the stepper motor?

The increment per unit time frequency can be used to calculate the "angular acceleration" of the motor.

We know that the "angular acceleration" multiplied by the "moment of inertia" of the load, plus the moment of resistance (e.g., friction), equals the torque of the motor.

One important statistic in the performance of each type of stepper motor is the maximum torque.

If the specified maximum torque is exceeded, a "loss of step" occurs.

Therefore, if the load inertia and resistance are determined, the "angular acceleration" cannot exceed a certain limit. That is, the increment per unit time frequency cannot exceed a certain boundary.

Therefore, the rate of change in frequency should not be too large. In particular, if the frequency is "abrupt", which means that the instantaneous angular acceleration is "infinite", it is obviously not possible. Therefore, it is best not to "mutate", but to "gradual", and it is best to make "uniform acceleration" and "uniform deceleration".

However, according to the principle of stepper motor, the loss of step usually must have a certain accumulation to occur, if there is occasionally one or two steps of acceleration overrun, as long as the next few steps do not exceed, usually will not lose step.

Therefore, it is best to "uniform acceleration" and "uniform deceleration" as I mentioned above, and if it is not completely uniform due to the difficulty of software implementation, it is often possible to make a small step type of "stepped acceleration and deceleration".

Gradually increase the frequency, and when it comes to startup, you can be sure that it can run at a fixed frequency, I recommend you find a book to read! Generally, the no-load is at a starting speed of 3 5 rpm, and the stepper motor is applicable.

To see how long the acceleration time is, isn't the tangent function of the straight line?

The stepper motor is used in low-speed applications, and the speed does not exceed 1000 revolutions per minute, so the maximum speed applicable is 1000 revolutions.

The rotational speed of the stepper motor depends on the pulse frequency, the number of rotor teeth, and the number of beats. Its angular velocity is proportional to the pulse frequency and is synchronized with the pulse in time. Therefore, when the number of rotor teeth and the number of operating beats are constant, the required speed can be obtained by controlling the pulse frequency.

Since the stepper bridge motor is started with the help of its synchronous torque, in order not to lose step, the starting frequency is not high. Especially as the power increases, the rotor diameter increases, the inertia increases, and the starting frequency and the maximum operating frequency can differ by as much as ten times.

The starting frequency characteristics of the stepper motor make it impossible for the stepper motor to directly reach the running frequency when it starts, but to have a starting process, that is, to gradually increase the speed from a low speed to the running speed. When stopping, the operating frequency cannot be immediately reduced to zero, but there must be a process of gradually decreasing the speed to zero at high speed.

The stepper motor is used in low-speed occasions--- the speed per minute does not exceed 1000 rpm, (6666pps when the degree), it is best to use it between 1000-3000pps (degree), and it can be made to work here through the deceleration device, at this time, the motor has high working efficiency and low noise.

It is best not to use the stepper motor in the whole step state, and the vibration is large when the whole step state is used.

Due to historical reasons, only the nominal 12V voltage of the motor uses 12V, the voltage value of other motors is not the driving voltage volt value, and the driving voltage can be selected according to the driver (Suggestion: 57BYG uses DC 24V-36V, 86BYG uses DC 50V, 110BYG uses higher than DC 80V), of course, the voltage of 12V can also be used in addition to the 12V constant voltage drive, but the temperature rise should be considered.

The stepper motor can run at a very high speed under no-load conditions, up to 3000rpm, but due to the characteristics of the moment frequency, the output torque of the motor at this time is very small, and there is no application value, the stepper motor is generally used within 600rpm, and there are more within 300rpm, which can give full play to the characteristics of the low-speed torque of the stepper motor.

The stepper loss motor needs 200 pulses in 1 revolution, that is, at 200Hz, the motor speed is 1rps, and at 8000Hz, it is 40rps. Pin side shot.

In half a step, 400 pulses are required for 1 turn, i.e. at 400Hz, the motor speed is 1rps, at 8000Hz, the speed is 20rps, and when 4 subdivisions, 800 pulses are required for 1 turn, i.e. at 800Hz, the motor speed is 1rps, and at 8000Hz, the speed is 10rps.

As can be seen from the above, the motor running speed = control pulse frequency (200 * subdivision value) rp.

There are two conditions that affect the speed of a stepper motor, the pulse frequency and the delay time of the delay subroutine. The higher the pulse frequency, the faster the speed of the step-start motor. The longer the delay time of the time-delay subroutine, the faster the stepper motor speed.

Calculation of stepper motor speed and number of running pulses.

After the driver is subdivided, the step angle of the stepper motor is degrees, and the input pulse frequency of the controller is 3000Hz, then the speed of the stepper motor is degree * 3000 seconds = 540 degrees of seconds, because the week is 360 degrees, so it is revolutions in seconds, multiplied by 60 is the speed per minute, that is, 90r min.

The stroke of a pulse motor is that it takes 2000 pulses for the motor to rotate 360°, and when the input control frequency is 3000Hz, the speed of the stepper motor is 3000 2000rps=

The stepper motor is a pulse signal to turn an angle, 10000 revolutions is a circle of 10000 pulses, the speed of the motor = the frequency of the control 10000 (for this model).

As an actuator, stepper motor is one of the key products of mechatronics, which is widely used in various automatic control systems. With the development of microelectronics and computer technology, the demand for stepper motors is increasing day by day, and they are used in various fields of the national economy.

Principle: Stepper motor is the right person in the industry"Stepper motors"A stepper motor is an open-loop control element that converts an electrical impulse signal into angular or linear displacement. In the case of non-overload, the speed of the motor and the position of the stop only depend on the frequency and number of pulses of the pulse signal, and are not affected by the change of load, that is, a pulse signal is added to the motor, and the motor turns a step angle.

The existence of this linear relationship, coupled with the fact that the stepper motor has only periodic errors and no cumulative errors. This makes it very easy to control with a stepper motor in the field of speed, position, etc.

Stepper motor is a kind of induction motor, its working principle is to use electronic circuits, the direct current into time-sharing power supply, multi-phase timing control current, use this current to supply power to the stepper motor, the stepper motor can work normally, the driver is for the stepper motor time-sharing power supply, multi-phase timing controller.

Although stepper motors have been widely used, stepper motors cannot be used under conventional use like ordinary DC motors, AC motors. It must be composed of a double ring pulse signal, a power drive circuit, etc., and the control system can be used. Therefore, it is not easy to use a stepper motor well, and it involves a lot of expertise in machinery, motors, electronics, and computers.

A stepper motor is an actuator that converts electrical impulses into angular displacements. In layman's terms: when the stepper driver receives a pulse signal, it drives the stepper motor to rotate at a fixed angle (and step angle) in the set direction.

You can control the angular displacement by controlling the number of pulses, so as to achieve the purpose of accurate positioning; At the same time, you can control the speed and acceleration of the motor rotation by controlling the pulse frequency, so as to achieve the purpose of speed regulation.

If the requirements are not high, the answer to this question is simple:

The speed of the stepper motor depends on the frequency of the pulse signal that your software sends to the stepper motor.

A fixed frequency corresponds to a fixed speed.

If you want to slow down, just increase the interval between each pulse a little bit; To accelerate, simply shorten the interval between each pulse a little bit.

If the requirements are higher, the problems that need to be considered are more complicated: the main thing is that the acceleration is too violent and there is the possibility of "losing step", in order to avoid the loss of step, it is usually necessary to determine the maximum absolute value of an acceleration according to the maximum torque of the stepper motor, the inertia of the load and other factors. Design the software algorithm according to the limits of this acceleration.

In this way, the implementation of the program requires a certain amount of skill.

If the requirements are not high, just keep the speed as low as possible.

Using the knowledge of geometry in junior high school, the acceleration start and deceleration stop of the stepper motor are realized.

Gradually increasing the frequency of the control pulse (decreasing the period of the control pulse) is the acceleration process, and gradually decreasing the frequency of the control pulse (increasing the period of the control pulse) is the deceleration process.

Just change the pulse width of the output pulse of the microcontroller!

The speed of the stepper motor is changed according to the change of the input pulse signal. That is, when the duty cycle of the input pulse increases, it accelerates, and when the duty cycle of the input pulse decreases, it decelerates.

Theoretically, when the driver is given a pulse, the stepper motor rotates by a step angle (or a step angle in the case of subdivision). In fact, if the pulse signal changes too fast, the magnetic reaction between the rotor and the stator will not follow the change of the electrical signal due to the damping effect of the reverse electromotive force inside the stepper motor, which will lead to stalled rotor and step loss.

Therefore, when the stepper motor starts at high speed, it is necessary to adopt the method of pulse frequency speed increase, and there should also be a speed reduction process when stopping, so as to ensure the precise positioning control of the stepper motor.