JPH05146505A - Motor control device for infusion pump - Google Patents

Abstract

PURPOSE:To reduce an electric power loss in staring the motor of an infusion pump by shortening a time elapsed until the determination of optimum and minimum necessary motor drive current. CONSTITUTION:A ROM 4 stores a table for starting motor drive current preliminarily obtained as a function adopting a power supply voltage value for a power supply 22 (battery) and an infusion rate as variables. The table is retrieved on the basis of the power supply voltage value read out from a power supply monitor circuit 26 and the infusion rate, and the corresponding data of the starting motor drive current is read out for application to a motor control circuit 20, thereby starting a drive motor 16. Immediately after the start of the motor 16, an operation for reducing the current value in step from the motor drive current at the time of motor start is repeated for determining optimum and minimum necessary motor drive current, thereby controlling the drive motor 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for an infusion pump used as a drive source for an intravenous infusion device such as a drip.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the electrical construction of a conventional infusion pump.

In the figure, 2 is a CPU (central processing unit) which controls the entire system, 4 is a ROM (read only memory) which stores a program for the control,
6 is a RAM (random access memory) that functions as a working memory for storing data, 8 is an input device such as a key panel, 10 is a display device such as a liquid crystal display panel, and 12 is a pump head portion that is a mechanism portion of an infusion pump. The pump head portion 12 includes a peristaltic infusion mechanism portion 14, a drive motor 16 that rotationally drives the infusion mechanism portion 14, and a motor rotation phase detection portion 18 that detects the rotation phase of the drive motor 16. It consists of and. Reference numeral 20 is a motor control circuit, 22 is a power supply (battery) for supplying electric power to each unit, and 24 is an alarm unit such as a lamp or a buzzer.

Next, the operation of controlling the drive motor 16 by the CPU 2 in the conventional infusion pump having the above structure will be described with reference to the flow chart shown in FIG.

In step n1, the CPU 2 controls the motor control circuit 20 to supply the driving motor 16 with a sufficient driving current sufficient to reliably rotate the driving motor 16 for driving. The motor 16 is started. The current value at the time of starting is set to a value having a margin so that the drive motor 16 can reliably start rotating even in the worst case.

At step n2, the CPU 2 drives the driving motor 1 based on the signal from the motor rotation phase detector 18.
It is checked whether 6 is rotating normally or is out of sync (motor check). When it is determined that the user is out of step, the process proceeds to step n3 to drive the alarm unit 24 to notify the operator of the step out.

When it is determined that the CPU 2 is rotating normally, the CPU 2 proceeds to step n4 and sets the motor control circuit 20.
To control the drive current supplied to the drive motor 16 to 1
Decrement (decrease) by the amount of steps. That is, if the current motor drive current is i _M and the current value for one step is i ₀ , the next motor drive current is
Set as i _M ← i _M −i ₀ . The current value i _{0 for} one step is appropriately determined depending on the model.

Next, in step n5, as in step n2, it is checked whether the drive motor 16 is rotating normally or out of synchronization, and the drive motor 16 rotates normally. If it is determined that there is, step n4
Then, the motor drive current i _M is decremented by one step i ₀ (i _M ← i _M −i ₀ ).
Then, the motor check is performed again in step n5.

Regardless of the decrement of the motor drive current i _M in step n4, the routine of steps n4 → n5 → n4 is looped unless the drive motor 16 is normally rotating in step n5 and it is judged that the step is out of step. Repeat. As a result, the motor drive current i _M is reduced by i ₀ by one step until step out occurs.

As a result of such a sequential decrease of the motor drive current i _M , when it is judged in the motor check in step n5 that the drive motor 16 is out of step, the process proceeds to step n6. In step n6, the motor drive current i _M is incremented by i ₀ for one step in order to return the rotation state of the drive motor 16 to the normal state (i
_{M ← i M + i 0)} . No alarm is issued for a step out in this case.

Then, in step n7, the contents of the register R for counting the number of executions in step n6 is incremented by +1.
Increment only (R ← R + 1). The initial value of the register R is set to zero.

At step n8, it is judged whether or not the content of the register R matches the predetermined number N of times. The value of N can be set arbitrarily, but in general, N = 3 to 5. When the content of the register R (that is, the number of times the motor drive current i _M is incremented by i ₀ for one step) has not reached the predetermined number N, the process returns to step n5 to repeat the motor check.

Since the step-out has been lost as a result of the drive current decrement in step n4, the drive current is incremented in step n6. However, this drive current increment does not always mean that the motor check in step n5 is normal. It may happen that the out-of-step condition remains. This is because the minimum drive current required for driving the drive motor 16 is affected by various factors such as the voltage of the power supply 22, the infusion rate, the temperature, and other factors, and thus varies slightly.
That is why the process returns to step n5 through steps n6, n7, and n8.

In step n5 after returning from step n8, when it is determined that the step-out condition continues, the motor drive current i _M is further incremented in step n6, and steps n7 and n8 are executed again. The process returns to step n5 and the motor check is repeated.

In step n5 after returning from step n8, if the rotation state of the drive motor 16 has returned to normal, the process returns to step n4 and the motor drive current i _M is decremented again. as a result,
If step out again, steps n5 → n6 → n7 → n8 → n
Go to 5.

That is, with respect to the rotation state of the drive motor 16, the motor drive current i _M is set across the boundary between normal and out-of-step.
Is being fine-tuned. If such fine adjustment is repeated a predetermined number of times N, the loop-like routine of steps n5 to n8 is exited. In that case, at step n6, the motor drive current i is determined after the step out judgment of step n5.
_{Since M} is incremented, it can be regarded as a normal rotation state for the time being, and the motor drive current i _M at the stage of exiting the routine is finally determined as the optimum drive current. Needless to say, this optimum drive current is the minimum drive current required to drive the drive motor 16.

As described above, at the time of start-up, a sufficiently large motor drive current is supplied to surely start the drive motor 16, and immediately thereafter, the motor drive current is gradually reduced while maintaining the optimum minimum necessary motor drive current. Seek out
After that, the control method of driving the drive motor 16 with the minimum required motor drive current is adopted.

The reason why such a control method is adopted is that
This is because the power consumption is reduced as much as possible and the operation time of the power source 22 (battery) is maximized. Also,
The fact that the current consumption is small means that the device is downsized,
This is advantageous in reducing the weight.

[0019]

However, when the infusion rate is low and the rotation speed of the drive motor 16 is low, it takes a long time to determine whether the rotation state of the drive motor 16 is normal or out of sync. It will take time.

That is, after the step n2 has passed, the routine of the cycle of steps n4 → n5 → n4, that is,
The number of times of repeating the process of performing the motor check while decrementing the motor drive current i _M by i _{0 for} each step becomes extremely large, and it takes a very long time to get out from step n5 to step n6.

As a result, it takes a long time from the start of the motor until the optimum motor drive current is determined, and a relatively large motor drive current is consumed during that time, resulting in a large power loss. There is a problem of becoming.

For example, when the infusion rate is several ml / hr or less, it is 30 before the optimum motor drive current is determined.
It may take more than a minute, and when the total operation time of the infusion pump is a relatively short time of about 1 to 2 hours, the ratio of the time required to determine the optimum drive current is too large, resulting in poor efficiency. At the same time, the power loss is inevitable.

A large power loss means that the power source 22
It means that if the capacity of the (battery) is constant, the total operating time by the power source 22 (battery) becomes short. If the total operating time is constant, the capacity of the power source 22 (battery) required is large. This means that the device will become larger and heavier.

By the way, contrary to the above, the drive motor 1
At the time of starting 6, the control method may be considered in which the optimum minimum required motor drive current is searched for while gradually increasing the motor drive current to bring the rotation state of the drive motor 16 to the normal state. In this case, almost no power loss occurs.

However, when the infusion capacity is low due to the step-out state of the drive motor 16 at the initial stage of starting, and the infusion rate is low and the rotation speed of the drive motor 16 is slow as in the above case,
The time lag from the start-up to the actual infusion of the drug solution is too long, which may interfere with the treatment.

The present invention was devised in view of such circumstances, and shortens the time required to determine the optimum minimum required motor drive current when starting the motor for driving the infusion pump. To reduce power loss.

[0027]

A motor control device for an infusion pump according to the present invention is provided with a motor control circuit for supplying a required drive current to a motor for driving an infusion mechanism, and at the time of starting the motor start. By repeating the operation of stepwise decreasing the current value from the motor drive current by one step, the optimum minimum required motor drive current is obtained, and this optimum drive current is given to the motor from the motor control circuit. A motor control device for an infusion pump having a control means, which is provided with a power supply voltage monitor circuit and which has a motor drive current previously obtained as a function having a power supply voltage value and an infusion rate as variables. Storage means having a table for setting the power supply voltage value and setting input read from the power supply voltage monitor circuit at the time of starting the motor. The table is searched based on the infusion rate and the corresponding data of the motor drive current at the start of starting is read out and this data is given to the control means as the motor drive current at the start of starting the motor. It is characterized by having and.

[0028]

In the infusion pump, what influences the drive current of the motor is, for example, the power supply voltage value, the infusion rate,
There are various factors such as the temperature and the condition of the infusion mechanism including the infusion tube. As a result of detailed examination of these, the present inventor has found that the power supply voltage value and the infusion rate have the greatest influence on the motor drive current. The above configuration of the present invention is based on this knowledge.

By experiment, the minimum required motor drive current for driving the motor is obtained by varying the combination of the power supply voltage value and the infusion rate as parameters. The data of the motor drive current thus obtained is stored in the storage means as a table as a function having the power supply voltage value and the infusion rate as variables.

In the above structure, the drive current initial value setting means searches the table based on the power supply voltage value read from the power supply voltage monitor circuit and the infusion rate that has been set and input, and drives the corresponding motor at the start of starting. Read the current data. The control means receives the data of the motor drive current at the start of the start and gives it to the motor control circuit as the motor drive current at the start of the motor start. This drive current is a minimum current value necessary for normally starting the motor.

Therefore, the same control means gradually decreases the current value for each step, which is performed immediately after the motor is started, and finally reaches the optimum minimum necessary motor drive current to be searched for. The time required up to this is significantly shortened as compared with the conventional example in which a sufficient margin as a drive current at the time of starting is taken into consideration.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a motor control device for an infusion pump according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the electrical construction of the infusion pump according to the embodiment.

In the figure, 2 is a CPU that controls the entire system, and 4 is a RO that stores a control program and a table relating to the motor drive current at the start of starting.
M and 6 are RAM as a working memory, 8 is an input device such as a key panel, 10 is a display device such as a liquid crystal display panel, 12 is a pump head part which is a mechanism part of an infusion pump, and 14 is a peristaltic infusion mechanism part. , 16 is a drive motor, 18 is a motor rotation phase detection unit, 20 is a motor control circuit, 22 is a power supply (battery) for supplying electric power to each unit, 24 is an alarm unit, and 26 is a voltage of the power supply 22 (battery). This is a power supply voltage monitor circuit.

The table stored in the ROM 4 is a table in which the motor drive current obtained in advance is used as the motor drive current at the start of the start as a function having the power supply voltage value and the infusion rate as variables. That is, by experiment, the power supply voltage value and the infusion rate are used as parameters, and the minimum required motor drive current for driving the drive motor 16 is determined while various combinations thereof are obtained, and the power supply voltage value and the infusion rate are used as a function. Is a table of motor drive currents at the start of starting.

The power supply voltage value of the power supply 22 (battery) is detected by a newly provided power supply voltage monitor circuit 26,
It is sent to the CPU 2. The infusion rate is given to the CPU 2 from the input device 8. CPU2 is a drive motor 16
Of the power supply voltage monitor circuit 26 based on the start command of
A function of searching the table of the ROM 4 based on the power supply voltage value read from the CPU and the infusion rate that has been set and input, reading the corresponding motor drive current data at the start of starting, and sending the data to the motor control circuit 20. have.

Next, in the infusion pump having the above structure, C
The operation of controlling the drive motor 16 by the PU 2 will be described based on the flowchart shown in FIG.

In step S1, the CPU 2 inputs the input device 8
The infusion rate is read, and in step S2, the power supply voltage value of the power supply 22 (battery) is read from the power supply voltage monitor circuit 26. Then, in step S3, based on the power supply voltage value and the infusion rate, the corresponding data of the motor drive current at the start of starting is read from the table of the ROM 4. The motor drive current at the start of starting is the minimum motor drive current required to reliably start the drive motor 16 under the conditions of the supplied power supply voltage value and the infusion rate.

In step S4, the CPU 2 supplies the motor control circuit 20 with the data of the motor drive current at the time of starting the start, and through the control of the motor control circuit 20,
The drive motor 16 is started with the motor drive current at the start of the drive. Again, the starting motor drive current at this time does not have a sufficient margin as in the conventional example, and has a value sufficiently close to the drive current required for reliable starting. There is.

The CPU 2 at step S5, based on the signal from the motor rotation phase detector 18, drives the motor 1 for driving.
It is checked whether 6 is rotating normally or is out of sync (motor check). When it is determined that the user is out of step, the process proceeds to step S6, and the alarm unit 24 is driven to notify the operator of the step out.

However, when it is determined that the motor is rotating normally, the process proceeds to step S7, the motor control circuit 20 is controlled, and the drive current supplied to the drive motor 16 is decremented by one step. Let That is, assuming that the current motor drive current is i _M and the current value for one step is i ₀ , i _M ←
It is set to i _M -i _0. The current value i for one step i
₀ is set appropriately depending on the model.

Next, in step S8, as in step S5, it is checked whether the drive motor 16 is rotating normally or out of synchronization, and the drive motor 16 is rotated normally. If it is determined that there is, step S7
To return the motor drive current i _M for one step i
Decrement by ₀ (i _M ← i _M −i ₀ ). Then, the motor check is performed again in step S8.

As described above, since the motor drive current at the start of start is sufficiently close to the minimum value required for motor start, the number of repetitions of the drive current decrement in step S7 and the motor check in step S8 is large. This is extremely small compared to the conventional example in which the excess margin was expected. Therefore, it is possible to exit from step S8 to step S9 early.

That is, this step S7 → S8 → S7
The processing time of the loop-shaped routine is significantly shortened as compared with the conventional example.

From step S8 to step S9,
In order to return the rotation state of the drive motor 16 to the normal state, the motor drive current i _M is incremented by i ₀ for one step (i _M ← i _M + i ₀ ). No alarm is issued for a step out in this case.

Then, in step S10, the contents of the register R for counting the number of executions of step S9 are incremented by +.
Increment by 1 (R ← R + 1). The initial value of the register R is set to zero.

In step S11, it is determined whether the content of the register R matches the predetermined number N of times. The value of N can be set arbitrarily, but in general, N = 3 to 5. When the content of the register R (that is, the number of times the motor drive current i _M is incremented by i ₀ for one step) has not reached the predetermined number N, the process returns to step S8 and the motor check is repeated.

Steps S7 → S8 → S9 → S10 → S1
A routine for circulating 1 → S8 → S7 is repeated a predetermined number of times N
Just repeat. As a result, with respect to the rotation state of the drive motor 16, the motor drive current i _M is finely adjusted across the boundary between normal and step-out, and the optimum minimum required motor drive current i _M in the normal rotation state is obtained. It can be finally decided.

As described above, the minimum required start-up motor drive current for the reliable start of the drive motor 16 is determined in advance, and the drive motor 16 is determined from the minimum required start-up motor drive current. Since the start of
It is possible to greatly reduce the time required to reach the optimum minimum necessary motor drive current to be finally searched by gradually reducing the current value for each step, as compared with the conventional example. You can do it.

[0050]

As described above, according to the present invention, at the time of starting the start-up which is obtained in advance as a function with the power supply voltage value and the infusion rate that have the greatest influence on the motor drive current among various elements as variables. A table of motor drive currents is stored in the storage means, and when the motor is started, the table is searched based on the power supply voltage value read from the power supply voltage monitor circuit and the infusion rate that has been set and input, and the corresponding start is performed. It is configured to read the data of the motor drive current at the start and give it to the motor control circuit as the motor drive current at the start of motor start. The motor drive current at the start of start normally starts the motor. Since it is the minimum current value required above, the current value is increased by one step immediately after the motor starts, regardless of whether the motor rotation speed is slow or fast. It can be shortened considerably as compared with the conventional example the time required to reach the optimum driving current to be searched ultimately went reduced to. That is, it is possible to shorten the time from the start of the start command for the motor to the stable rotation of the motor with the minimum required drive current in the state where no step out occurs, and the motor start processing is performed efficiently with less power loss. be able to.

Therefore, if the capacity of the power supply (battery) is constant, the total operating time by the power supply (battery) can be extended, and if the total operating time is constant, the required power supply (battery) is required. It is possible to reduce the capacity and reduce the size and weight of the device.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an infusion pump to which a motor control device for an infusion pump according to an embodiment of the present invention is applied.

FIG. 2 is a flowchart for explaining the operation of the embodiment.

FIG. 3 is a block diagram showing an electrical configuration of a conventional infusion pump.

FIG. 4 is a flowchart for explaining the operation of a conventional example.

[Explanation of symbols]

2 CPU 4 ROM (including a table of motor drive current at the start of start) 14 Infusion mechanism section 16 Drive motor 20 Motor control circuit 26 Power supply voltage monitor circuit

Claims (1)

[Claims] 1. A motor control circuit for supplying a required drive current to a motor for driving an infusion mechanism, and the current value for each step is gradually reduced from the motor drive current at the start of motor start. A motor control device for an infusion pump, comprising: a control unit configured to obtain an optimum minimum required motor drive current by repeating the operation of causing the motor to supply the optimum drive current to the motor from the motor control circuit. A storage means having a voltage monitor circuit, a table having a motor drive current obtained in advance as a motor drive current obtained as a function of a variable having a power supply voltage value and an infusion rate as variables, and the power supply for starting the motor. The table is searched based on the power supply voltage value read from the voltage monitor circuit and the set and input infusion rate. The motor control device of the infusion pump, characterized in that a drive current initial value setting means for providing a motor drive current at the start motor starting to the control means the data read out data starting at the start motor drive current.