阅读说明：本技术 一种医用多轴步进电机同步方法 (Medical multi-shaft stepping motor synchronization method ) 是由 钟晓玲 杨国波 陈阳 于 2019-08-28 设计创作，主要内容包括：本发明公开了一种医用多轴步进电机同步方法。提出基于等差数列公式的增量单位时间脉冲的方法来进行同步,避免了步进电机只有从零速度启动到相同速度的多余时间,使得多轴电机在同步的过程中速度时间曲线更加平滑,达到更加稳定的效果,使医疗检验和科研的实验结果更加精确。(The invention discloses a medical multi-axis stepping motor synchronization method. The incremental unit time pulse method based on the arithmetic progression formula is provided for synchronization, redundant time from starting of the stepping motor only from zero speed to the same speed is avoided, a speed time curve of the multi-shaft motor in the synchronization process is smoother, a more stable effect is achieved, and the experimental results of medical inspection and scientific research are more accurate.)

1. A medical multi-shaft stepping motor synchronization method is characterized by comprising the following steps:

s1, firstly, comparing the pulse number of all stepping motors in unit time with the number of pulses of motors to be synchronized;

s2, obtaining the difference value of the pulse number of each stepping motor in unit time;

and S3, deducing by using an equation of an arithmetic progression to obtain the number of pulses of each stepping motor to be synchronized in unit time, wherein the number of the pulses of each stepping motor to be synchronized needs to be increased, otherwise, accelerating or decelerating the stepping motor to be synchronized according to a method of increasing or reducing the rated pulse number e in unit time.

2. The medical multi-axis stepping motor synchronization method according to claim 1, wherein in step S1, an FPGA is used as a main control chip to control the multi-axis stepping motor, and the parallelism of the FPGA is convenient to control.

3. The medical multi-axis stepping motor synchronizing method according to claim 1, wherein in step S3, the pulse number increment per unit time is calculated using an arithmetic progression formula, and the speed-time curve is smoothed according to the relationship that the pulse number per unit time and the speed are in direct proportion, so that the experimental results of medical examination and scientific research are more accurate.

Technical Field

The invention relates to the field of medical motion control, in particular to a method for synchronizing a plurality of stepping motors.

Background

In medical inspection and scientific research, the requirement for automation is higher and higher. Many medical instruments need to do a plurality of complicated movements to reach the automation, reduce human participation, liberate the labour. And the use of a multi-axis stepper motor enables automation. And the parallel control of the multi-shaft motor makes the control of the multi-shaft motor special. Considering the cost and the simplicity of control, the current main control modes of taking the FPGA as a main control chip are gradually increased, and the photoelectric encoder is taken as a feedback device. Due to different medical examination application scenes, such as shaking, standing and the like, the time and motion control requirements are different, and the requirements of the same speed and different speeds are simultaneously met for a plurality of stepping motors. In order to achieve a certain effect, such as a comparison experiment, in order to start a simultaneous shaking experiment after different operations, stepping motors with different speeds are driven to move towards the same speed at the same time. How to make the stepping motors with different speeds stably approach to the same speed becomes the key point of the accuracy of the experimental result. The asynchronous motor performs speed synchronization under the condition of different speeds, and is an important condition for whether medical inspection and scientific research results are accurate or not. At present, a plurality of stepping motors are adopted by a plurality of medical instruments to be simultaneously static, and then the same frequency is used at the same time to start. This increases the jitter possibilities, although comparative experiments can also be done. The step motor has a large jitter due to the load from the time when the initial speed is zero to the time when the initial speed is available. Thereby failing to achieve the expected effect of the experiment.

Disclosure of Invention

The invention provides a medical multi-axis stepping motor synchronization method in order to solve the problem of multi-axis stepping motor synchronization in the prior art.

A medical multi-axis stepping motor synchronization method is based on an FPGA to control a multi-axis stepping motor and comprises an FPGA main control chip and a plurality of stepping motors. The system structure schematic diagram of the invention is shown in fig. 1, the algorithm flow is as follows, and the step of controlling a plurality of stepping motors to carry out synchronization at a certain speed comprises the following steps:

s1, firstly, comparing the pulse number of all stepping motors in unit time with the motor to be synchronized.

And S2, obtaining the difference value of the pulse number of each stepping motor in unit time.

And S3, deducing by using an equation of an arithmetic progression to obtain the number of pulses per unit time required to be increased for each stepping motor to be synchronized. Otherwise, the stepping motor to be synchronized is accelerated or decelerated according to the method of increasing or decreasing the rated pulse number e per unit time.

The specific principle of the above steps is explained below.

1. At this time, the FPGA chip and the stepping motor are both powered on, and all motors are required to be synchronized to the speed of the motor 1.

2. By the formula v ═ P × θ m/360, where v is the motor speed, P is the pulse frequency, θ is the motor natural step angle, and m is the subdivision. It is known that frequency and velocity are in a direct proportional relationship. Then defining the frequency P1 of a motor1 of the stepping motor, wherein the current speed is V1, the subdivision number is theta 1, the subdivision number is m1, and q1 pulses are needed for one turn; the motor2 has the frequency P2, the current speed is V2, the subdivision number is theta 2, the subdivision number is m2, and q2 pulses are needed for one rotation.

3. The number of pulses per unit time S1 q 1V 1, the number of pulses per unit time S2 q 2V 2, and the acceleration and deceleration Tmin of the standard-value motor given the unit time, may be obtained by an arithmetic progression formula, where the difference between the numbers of pulses per unit time S α S1-S2| q 1V 1-q 2V 2| P1 θ 1 m 1V 84-P2 | θ 2 m 2V 2 |.

4. And (3) taking the minimum value г of the two numbers S1 and S2 to be min { S1, S2}, if the minimum value is S1, increasing the pulse per unit time of the motor2, otherwise, obtaining the pulse number d increased or decreased per unit time according to an arithmetic progression formula α to Tmin г + Tmin (Tmin-1) to d/2.

5. If the number of pulses per unit time d is greater than the rated number of pulses e increased per unit time of the stepping motor2, the stepping motor2 is accelerated or decelerated in such a manner that the rated number of pulses e is increased or decreased per unit time.

6. From the formula S q v, it can be seen that the number of pulses per unit time is proportional to the speed of the stepping motor. The equivalent increase or decrease of the pulse number in unit time, the speed-time curve is smooth, and the effect of stable smooth synchronous stepping motor speed is achieved. Meanwhile, each stepping motor and the stepping motor1 perform the same operation, and finally, the synchronization is completed.

The invention has the beneficial effects that:

1. because the pulse number in unit time is used for each increment synchronously, the method is more stable compared with the method directly using the frequency conversion.

2. Due to the parallelism of the FPGA, the controlled stepping motors can move simultaneously, and the increment of pulse passing in unit time of a plurality of stepping motors can be simultaneously carried out during synchronization. The whole system is stabilized.

Drawings

FIG. 1 is a system framework diagram of the present invention.

Detailed Description