JPH01201255A - Method for controlling patient travelling grate device - Google Patents

Abstract

PURPOSE:To prevent the inconvenience of the plugging, sag, etc., of a belt from occurring by calculating the quantity of a belt wound out by an upper roller and a lower roller and position-controlling an inserting plate during motor suitably by the moving position of the inserting plate. CONSTITUTION:The seat part of a patient travelling grate device is composed of a slidable inserting plate 6 in a horizontal direction and a belt 7 hung on the plate 6 while both edges are wound to rollers 8 and 9 in the upper and lower directions separately, and inserted between a patient 10 and a head 11. Then, a lower roller 9 only pays out the belt 7, the correlation of a patient 10 and the belt 7 does not change, the friction between the inserting plate 6 and the bed can be decreased and the smooth insertion can be executed. The action of the inserting plate 6 is executed by an ordinary PI speed control means 25 and for the belt roller, a position control means 26 of PD and PID is used. Thus, the positional relation of the inserting plate and the belt roller can be always suitably kept.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for controlling an assistance patient transfer device used for assisting bedridden patients in medical facilities such as hospitals and rehabilitation centers. be.

<Conventional technology> In medical facilities such as hospitals and rehabilitation centers, bedridden patients are automatically picked up and taken to the toilet, bathroom, etc.
There are increasing social expectations for the realization of patient transfer devices for transporting patients to treatment rooms, etc., not only to reduce the burden on caregivers, but also to assist patients in acting according to their own will.

FIG. 3 shows an example of this, which consists of a seat portion 1 that slides horizontally and lifts up a patient on the bed, and an omnidirectional movable trolley 2.

In this device, the seat portion 1 consists of a roughly horizontal waist support portion 3, a leg support portion 4 in front of it, and a back support portion 5.
The shape of the stretcher can be changed from a stretcher shape in which each of the receivers 3, 4, and 5 are approximately horizontal to a wheelchair shape in which the leg receivers 4 are rotated downward and the back receiver 5 is rotated upwards. In this state, the patient can be lifted up by sliding the seat portion horizontally and inserting it between the patient and the bed.

FIG. 4 shows the seat portion of the patient transfer device shown in FIG.

This part consists of an insertion plate 6 that can be slid in the horizontal direction, and a roller 8 that is hung on the plate 6 and that is attached to the upper and lower ends of the insertion plate 6.
It consists of a belt 7 wound around a belt 9.

5a, b, c, and d show how the patient is lifted using the above-mentioned device, and the insertion plate 6 slides and is inserted between the patient 10 and the bed 11.
At that time, only the lower row 59 lets out the belt 7 so that the relative relationship between the patient 10 and the belt 7 does not change at all times, reducing the friction between the insertion plate 6 and the bed and allowing smooth insertion. .

In addition, in FIGS. 4 and 5, another plate 12 located below the insertion plate 6 is connected to a lower belt 14 whose front lower part 15 is fixed to the lower table 13, and is attached to the other plate 12 under the insertion plate 6. It is inserted between bed 10 and bed 11, but it is inserted between bed 11 and lower belt 1.
4 is kept constant, and plates 6, 12 . bed 11
It works to reduce the friction between the two.

Further, as shown at 15.16 in Fig. 4, drive motors are arranged, one each on the upper and lower sides for rotating the belt rollers 8 and 9, and one each for driving the insertion plate 6 (not shown). has been done.

In a patient transfer device having the above mechanism, when lifting and inserting a patient, the insertion plate 6 must be operated at a constant speed that does not cause discomfort to the human body.

If the speed is too high, it may cause discomfort such as pain to the patient, and if the speed is not constant, it will also be uncomfortable.

Also, during insertion, the lower belt roller 9 moves according to the advancement of the insertion plate 6.
You need to rotate it.

At this time, if the speed of the insertion plate 6 is V7(t), and the speed of the lower part of the belt 7 applied to the insertion plate 6 is V), L(t), then V, U(, -t-) = 2 Vb, +(t)・・・・・・
- If controlled so as to achieve (1), the belt 7 on the upper part of the insertion plate 6 remains stopped and there is no relative change in the patient contact position, so smooth insertion is possible.

Therefore, when the drive motor of the plate 6 and the drive motor 16 of the lower belt roller 9 are rotated separately at a constant speed, a control method that adds integral compensation operation to proportional control is used.
ilJ61] is often used.

Now, consider the motor drive current i as 2=Kp(ω.-ω>+KJ-ω)dt (2). Here ω. is the target rotational angular velocity of the motor, ω
is the current value of the angular velocity.

The target values of the rotational speeds of the insertion plate 6 and the rollers 9 may be selected in consideration of their respective rotation transmission mechanisms so as to satisfy equation (1).

<Problems to be Solved by the Invention> In the control device for the patient transfer device as described above, when inserting the insertion plate 6 between the patient 10 and the bed, the weight of the patient 10 is not affected by the plate drive servo system. Acts as a disturbance.

That is, at the point when insertion of the insertion plate 6 between the thought 10 and the bed 11 is started, a frictional force that resists the rotation of the motor is generated between the patient 10, the belt 7, and the insertion plate 6 as a disturbance, and the speed remains constant until then. The speed of the insertion plate 6, which was being driven at , decreases.

However, in PIII+IJtll, as the error between the current speed and the target speed increases, the output of the integral term gradually increases, and an output sufficient to resist the disturbance is obtained, and even if there is friction due to the human weight, the It has the property of returning to its original speed.

On the other hand, the frictional force caused by the human weight acts as a disturbance on the plate drive motor, but does not cause a disturbance on the drive motor 16 of the belt 7.

The speed of the drive motor for the insertion plate 6 temporarily decreases when the insertion of the insertion plate 6 is started, but during this time the motor 16 that feeds out the belt does not decrease in speed and continues to rotate at a constant speed.

While the speed of the insertion plate 6 is decreasing, the relationship in equation (1) above is disrupted, so the excess belt 7 is unavoidably let out, resulting in slack as shown in Fig. 6. .

Next, as shown in FIG. 7, the patient 10 placed on the patient transfer device is rolled up by the lower belt row 59, and the upper belt roller 8 is rotated in the feeding direction to move the patient 10 on the device, thereby correcting the positional deviation. In this case, both rollers 8.9 need only rotate at the same speed, but it is the lower roller 9 that pulls the load of the patient 10.

Therefore, the speed of the roller 9 to which the load is applied decreases, but since no load is applied to the upper roller 8, it continues to rotate at a constant speed.

Therefore, the belt 7 becomes slack as in the case described above.

The slackness of the belt 7 as described above hinders the next operation.

That is, the tensile force of the belt 7 is not transmitted to the patient 10 until the belt 7 is no longer slack.

Furthermore, since the relationship between the amount of winding of the belt 7 becomes unstable, there is a problem that an initialization operation is required every time the child is picked up.

In order to solve the above problem, there is also a method as shown in FIG.

This method uses a target speed signal ω of the drive motor of the insertion plate 6.

is input to the insertion plate drive motor speed control means 21, and the output signal controls the insertion plate drive motor to operate the insertion plate.

However, since the current operating speed ω of the insertion plate 6 fluctuates due to the friction generated between the patient 10 and the bed 11, the speed of the insertion plate 6 is constantly monitored by detecting this current motor speed ω, and the speed of the insertion plate 6 is constantly monitored. is input to the speed conversion means 2, and the output signal ω2 is input to the belt roller motor speed control means 23.
is input, and the belt roller drive motor is controlled by the output signal ω' to synchronize the current speed of the insertion plate 6 and the speed of the belt 7.

This method works effectively for lifting, inserting the insertion plate 6, and other operations because the speed of the belt roller is adjusted in real time.

However, this method is basically realized by speed control, and does not pay attention to the positional relationship between the insertion plate 6 and the belt 7 at each point in time, so the minute error caused by the - insertion operation remains unchanged. remain.

Therefore, the method shown in Fig. 8 does not cause any problems when inserted several times, but if the method is operated continuously several thousand times, errors will accumulate and problems such as loosening of the belt 7 will occur. There's a problem.

<Problems to be Solved by the Invention> This invention was made to solve the above-mentioned problems, and consists of two flat plates that are stacked one on top of the other with a slight gap between them and are integrated into one piece. The insertion plate is attached to the board so that it can move forward and backward in the horizontal direction, and a pair of upper and lower rollers are placed behind the board. The lower belt is wound up in an O-shape and its ends are fixed to each roller, and both ends of the lower belt guided downward from the upper surface of the lower flat plate are fixed near the substrate, and each of the rollers is separately attached. Further, the board is provided with a drive means for advancing and retracting the insertion plate, and the drive means for advancing and retracting inserts the insertion plate under the patient during insertion. When the plate is retracted, the upper and lower rollers are driven to cause the belt to retract together with the insertion plate.In the patient transfer device, the insertion plate drive motor is turned ff, 1J61] using an appropriate speed control method, and the upper and lower rollers are driven by the upper and lower rollers. A device that measures the hanging of the belt that should be unwound by the roller or lower opening, and appropriately controls the position of the drive motor for the upper roller or lower roller to prevent inconveniences such as belt clogging and loosening. It is.

<Embodiment> FIG. 1 shows an embodiment of an apparatus for carrying out the method of the present invention.

The insertion plate 6 is operated by a normal PI speed control means 25, but the belt roller uses a PD or PID position control means 26.

Also, in the figure, 27 is a position conversion block, and 28 is an insertion plate motor +
The insertion mechanism 29 is a belt roller motor ten roller compensation mechanism. In the case of PD control for belt roller rotation angle θ and target angle θd, j = Kp (θd - θ) + Kd (δd
-θ)...(3) In the case of PID control, εJ(θ
The motor current value is determined by d-θ)(It...(4).

The target value θd of the belt roller is calculated based on the rough operating position of the insertion plate.

The calculation function is the position conversion block 27 in FIG.

The calculation algorithm in this block is shown below.

In FIG. 2, if the position of the tip of the insertion plate 6 is x, the rotation angle of the upper roller 8 is θ, and the rotation angle of the lower roller 9 is 02, then when the insertion plate 6 moves Δχ during the insertion operation, the upper belt It is sufficient if the lower belt is unwound by 2Δχ without operating.

Further, if the rotational radius of the belt rollers 8 and 9 is r2, then from 2Δn=r2Δθ2 (5), the increase in the rotational position of the lower roller Δθ2 is as follows. However, r2 gradually changes depending on the number of times the belt is wound in a row.

Therefore, if t is the thickness of the belt, n2 is the number of turns of the belt, and rO is the radius of the belt roller 9 itself, then r 2 = r, Q + n 2 j... (
7), so in the end, Δθ2=□ (8) By setting ↑, we can find the increase in rotational position Δθ2 of the belt roller.

Assuming that the current rotational position of the belt roller is θ, the next target position can be determined by θ tool−θ2o+Δθ2.

Here, θ2 is the position of the belt roller 9, but actual control is performed using the rotational position of the motor.

The positional relationship between the motor and rollers can be supported as a linear relationship by constants due to a unique transmission system such as a reduction ratio using gears.

In the retracting operation that follows the insertion operation, the belt is unwound from the upper roller and the lower roller and is loosely wound).Since the belt depth becomes Δχ, the needle barrel can be formed by setting 2Δχ in equation (8) to Δχ.

Effects> As described above, this invention controls the IT and IJ controls of the insertion plate and belt roller of the patient transfer device based on their absolute positional relationship rather than their speed relationship. The positional relationship of the rollers is always maintained appropriately.

Therefore, the phenomenon of accumulation of position errors, which is a problem when controlling only by speed control, does not occur.

Therefore, the patient transfer operation can always be performed in a good condition for continuous operation.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a device that implements the control method of the present invention, Fig. 2 is an enlarged side view showing the relationship between the belt and the upper and lower rollers, Fig. 3 is a perspective view of the breather transfer device, and Fig. 4 5 is a perspective view of the same sheet portion as above, FIGS. 5 a, b, c, and d are front views showing each step of lifting by the above device, FIG. 6 is a front view showing slack in the belt, and FIG. 7 is a roller FIG. 8 is a front view showing a method for correcting positional deviation due to rotation of the motor, and FIG. 8 is a block diagram showing an example of a conventional control method. 6...Insertion plate 7...Belt 8
...Upper roller 9...Lower roller 2
5...PI speed control means 26...PD or PID position control means 27
...Position conversion block 28...Insertion plate motor + insertion mechanism 29...
...Belt roller motor + roller mechanism Fig. 6 Fig. 6 So Fig. 7

Claims (1)

[Claims] The insertion plate, which is made up of two flat plates stacked one above the other with a slight gap, is mounted on the board so that it can move horizontally forward and backward.A pair of upper and lower rollers is placed behind the board, and the insertion board is Both ends of the upper belt, which is passed up and down from the front edge of the upper flat plate and guided backwards, are wound around the upper and lower rollers, and the ends are fixed to each roller, and the upper belt is passed from the top surface of the lower flat plate to both ends and downward. Both ends of the guided lower belt are fixed close to the board, and roller drive means are provided to drive each of the rollers in forward and reverse directions separately.Furthermore, the board is provided with drive means for advancing and retracting the insertion plate, and when inserting The insertion plate is advanced by the advancing/retracting driving means, and the belt is fed out from the lower roller with the upper roller stopped, so that the insertion plate is inserted under the patient.When the insertion plate is retracted, the upper and lower rollers In a patient transfer device in which the belt is moved back together with the insertion plate by driving the insertion plate, the insertion plate drive motor is controlled by an appropriate speed control method, and the upper roller or lower roller unwinds the belt depending on the movement position of the insertion plate. Control of a patient transfer device characterized by calculating the amount of belt that should be removed and appropriately controlling the position of a drive motor for an upper roller or a lower roller so as to prevent inconveniences such as clogging or loosening of the belt. Method.