JPH05561B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method of driving a driven system using an elastic contracting body whose contraction amount is determined according to internal pressure in the drive system.

(Prior art and its problems) Elastic contractile bodies that expand in the radial direction and contract in the longitudinal direction when pressurized fluid is introduced are lighter in weight and move more smoothly than devices that use electric motors or hydraulic cylinders. It has many excellent features not found in conventional actuators, such as being able to perform positioning reliably, and various applications are being considered that take advantage of these characteristics.

FIG. 1 shows a torque motor 1, a servo valve having nozzles 2 and 3, a flapper 4, and a throttle valve 5 and 6, two elastic contraction bodies 7 and 8 arranged in series, and these two elastic contraction bodies. It is a linear drive device using pressurized air consisting of a mass point 9 connected to the body. The operation of driving the mass point 9 will be explained. First, a current is applied to the torque motor 1, and the flapper 4 is moved by the arrow A in the figure.
Suppose that it is shifted in the direction shown by . Therefore, the distance between the nozzles 2, 3 and the flapper 4 is small on the nozzle 2 side and large on the nozzle 3 side, and the back pressure on the nozzle 2 side approaches the supply pressure of pressurized air, and the back pressure on the nozzle 3 side increases. approaches atmospheric pressure. As a result, pressurized air is supplied to the elastic contraction body 7, and pressurized air is exhausted from the other elastic contraction bodies 8, so that the mass point 9 is displaced in the direction shown by arrow B. If the flapper 4 is displaced in the direction opposite to the arrow A, the mass point 9 will be displaced in the opposite direction to the arrow B.

However, devices that use the above-mentioned drive method use expensive torque motors, which inevitably increases costs, and the response speed is also slow.
Since pressurized air is constantly released, the compliance, which is generally expressed as the reciprocal of the elastic modulus E, of the drive system consisting of the two elastic contracting bodies 7 and 8 can be changed or stabilized while the mass point 9 is stationary. There was a problem that it was not possible to hold it. This compliance problem can be said to be a fatal drawback for drive systems using elastic contractile bodies.

(Object of the Invention) The present invention was made to solve the above-mentioned problems, and its purpose is to use two elastic contracting bodies without using the expensive servo valves that have been used in the past. It is possible to drive the connecting part connecting each of the elastic contracting bodies to a desired position with better responsiveness while imparting the desired compliance to the elastic contracting bodies, and furthermore, it is possible to drive this compliance in a stable state. It is an object of the present invention to provide a method for driving a connecting portion that can be easily controlled under the conditions.

(Structure of the Invention) In order to achieve this object, in the method for driving a connection part of an elastic contractile body of the present invention, the amount of contraction is determined according to the internal pressure, and the inflow amount is controlled to each of a set of two elastic contracture bodies. A valve and an outflow control valve are respectively provided, and the connecting portion of the elastic contracting body is rotated and/or translated by the contraction force in the axial direction of the elastic contracting body generated by supplying and discharging pressurized fluid to each elastic contracting body. In this case, prior to driving the connecting portion, each inflow control valve is opened while each outflow control valve is closed, and after pressurizing each elastic contractile body to a predetermined pressure, each inflow is closed. The amount control valve is closed and the connecting portion is elastically held at a predetermined position. Then, when driving the connecting portion, the inflow amount control valve of one of the elastic contracting bodies is opened to reduce the internal pressure of this elastic contracting body to the initial pressure. At the same time, open the outflow control valve of the other elastic contraction body to lower the internal pressure of this elastic contraction body by a pressure approximately corresponding to the pressure increase of the one elastic contraction body, and close those control valves. It is characterized in that it is closed, whereby the connecting portion is rotated and/or translated to a predetermined position while being elastically held, and then stopped.

(Example) Hereinafter, an example of a method for driving a connecting portion of an elastic contractile body according to the present invention will be described based on an apparatus shown in the drawings.

FIG. 2 is a schematic diagram showing an example of a device for realizing the driving method of the present invention using pressurized air as the pressurized fluid. In the figure, reference numerals 10 and 11 are elastic contracting bodies, and these elastic bodies are provided with reinforcing cords having a braided angle of θ ₀ , and these reinforcing cords extend in opposite directions with respect to the axis of each elastic contracting body, as shown in the figure. They are arranged on a rubber or rubber-like elastic body so as to be inclined and intersect with each other. One end of each of the elastic contraction bodies 10 and 11 is fixed to a fixed wall indicated by diagonal lines in the figure, and the mutually opposing ends are connected by a connecting member or a mass point 12.

The illustrated flow control valves 13, 14, 15, and 16 are suitable for the present invention, and among these flow control valves, 13 and 15 in the figure control the flow of pressurized fluid based on control signals from the illustrated control device. This is an electromagnetic inflow control valve that controls the inflow amount, and the inflow control valve 13 is connected to the elastic contraction body 10, and the inflow control valve 15 is connected to the elastic contraction body 1.
1 through pressurized fluid conduit sections, respectively.

These flow control valves 13 and 15 are supplied with pressurized air from a pressurized air supply source (not shown) through a conduit from the bottom of the figure, and the pressurized air is elastically contracted through the conduit section above the figure. It is configured to supply to the bodies 10 and 11. In addition, 14 and 16 in the figure indicate an outflow for releasing the pressurized air filled inside the elastic contracting bodies 10 and 11 to the atmospheric pressure side above the figure through the conduit part based on the control signal from the control device in the figure. This is an electromagnetic outflow control valve that controls the amount.

The outflow control valve 14 and the outflow control valve 16 are connected to the elastic contraction body 10 and the elastic contraction body 11 through pressurized fluid conduit portions, respectively.

An example of the structures of the inflow control valves 13, 15 and outflow control valves 14, 16 described above is shown in FIG. The electromagnet 17 is electrically connected to the control device shown in FIG. 2, and the electromagnetic force of the electromagnet 17 is continuously changed by continuously changing the coil voltage of the electromagnet 17 based on the signal voltage output from the control device. It is possible to change the As a result, the pressurized fluid acting in the direction of the upward arrow shown in FIG.
The flow rate is controlled by continuously changing the force that causes the valve body 18 made of a magnetic material to shift toward the valve seat 19 against the pressing force acting through the nozzle portion 20. Here, flow rate control means that after the valve body 18 opens and allows a predetermined amount of pressurized fluid to flow in or out in the direction of the arrow pointing to the right in FIG. 3, the valve body 18 remains closed. It means that.

Next, a method for driving a connecting portion according to the present invention using the above-mentioned device will be explained.

First, when the elastic contraction bodies 10 and 11 are separated and independent, each elastic contraction body produces a contraction action when filled with pressurized air, and the amount of contraction is determined by the pressure of the pressurized air. Determined. Therefore, as shown in FIG. 2, one end of each of the elastic contracting bodies 10 and 11 facing each other is connected to the connecting member 12, and the other end of each is fixed to a fixed wall. When the outflow control valves 14 and 16 are closed and the inflow control valves 13 and 15 are opened to allow a predetermined amount of pressurized air to flow into the elastic contraction bodies 10 and 11, a contraction force is applied to both of these elastic contraction bodies. occurs. This contraction force causes the elastic contraction bodies 10 and 11 to have a specific value of compliance or elastic modulus. In this case, the inflow control valves 13 and 15 are closed after a predetermined amount of pressurized air has been introduced.

As described above, the connecting portion 12 is elastically held by a system having a specific compliance value. Further, the connecting portion 12 comes to rest at a position where the contraction forces acting on the elastic contraction bodies 10 and 11 are balanced. In this case, the internal pressures of the elastic contraction bodies 10 and 11 do not necessarily have to be the same, and may be different pressures.

To move the connecting portion 12 from the above-mentioned stationary position to a desired position, the following method may be followed. That is, only the outflow control valve 16 provided on either one of the elastic contraction bodies 10 or 11, for example, the elastic contraction body 11, is opened, and after a predetermined amount of pressurized air is released, this outflow control valve is closed. Then, the internal pressure of the elastic contractile body 11 is set to be equal to or lower than the above-mentioned initial pressure. In this way, since the contractile forces of the elastic contractile bodies 10 and 11 are different from each other, as a result, the connecting portion 12 is elastically held with a specific compliance value until the second It moves to the right in the figure, stops, and comes to rest.

The above is an example in which only the outflow control valve 16 is opened and the other control valves are closed.
If only the inflow control valve 13 of No. 0 is opened and all other control valves are closed, the connecting portion 12
is elastically maintained with a specific compliance value, moves to the right in FIG. 2, and then stops and stands still.

As shown in FIG. 2, elastic contracting bodies 10 and 11
A predetermined standard is a state in which the air pressure P ₁ is set to approximately the same value by the method described above, and from this state, the inflow control valve 13 is opened while the outflow control valve 14 of the elastic contractile body 10 is closed, and the elastic contraction is performed. A predetermined amount of pressurized air is allowed to flow into the body 10, and its internal pressure is set to ΔP.
After increasing the amount by ΔP, the inflow control valve 13 is closed, and in conjunction with this operation, the inflow control valve 15 of the elastic contracting body 11 is closed and the outflow control valve 16 is opened to increase the flow rate approximately corresponding to the above-mentioned ΔP. After the amount of pressurized air is allowed to flow out from the elastic contraction 11, the outflow amount control valve 1
By performing the action of closing 6,
The connecting portion 12 is elastically maintained with a predetermined compliance value, moves to the right in FIG. 2, and stops at a position where the contraction forces of both elastic contraction bodies are balanced.

Driving the connecting portion 12 through the series of operations described above can be achieved by applying signal voltages from the control device shown in FIG. 2 to the respective control valves 13, 14, 15 and 16. Here, the two elastic contracting bodies 1
Compliance of the drive system consisting of 0,11,
When changing the connection part or its mass point 12 while being held in a predetermined position, depending on the desired compliance, the closed inflow control valves 13 and 15 are opened almost simultaneously, and each of the elastic contracting bodies 10 and 11 is Either supply approximately the same amount of pressurized fluid, or open the closed outflow control valves 14 and 16 at approximately the same time to cause approximately the same amount of pressurized fluid to flow out from each of the elastic contracting bodies 10 and 11. . In this way, the compliance of the drive system made up of the elastic contraction bodies 10 and 11 can be set to a desired value. Note that the flow control valve used in the present invention is not limited to the above-mentioned flow control valve, but any valve that can perform the above-described series of operations in response to a control signal to control the flow rate can be used.

Next, the operation of driving and shifting the connecting body 12 using such a device will be explained using mathematical expressions.
When the air pressure acting on the elastic contraction body 10 or 11 is P, the contraction force f generated in each elastic contraction body is
is generally expressed as follows, where the same force f acts on the mass point m in the opposite direction and it is in a stationary state.

f=π/4D ₂ P/sin ² θ ₀ {3cos ² θ ₀ (1−ε) ² −
1}≒k ₁ P−k ₂ Pε……(1) However, D is the outer diameter when internal pressure P is applied to the elastic contractile body, θ ₀
is the heave angle of the reinforcing cord, and ε is the strain when internal pressure P is applied to the elastic contractile body.

Now, a predetermined pressure P ₁ is applied to both elastic contracting bodies 10 and 11.
acts, and when the contraction forces of both elastic contraction bodies are in equilibrium with each other, in order to give the mass point 12 of the connection part a deviation of x in the direction of the arrow in FIG. The outflow control valve 14 of the elastic contraction body 10 is closed, the inflow control valve 13 is opened, and a pressure of ΔP is further applied to the elastic contraction body. At the same time, conversely, the inflow control valve 15 of the elastic contractile body 11 is closed, the outflow control valve 16 is opened, and a reducing pressure of -ΔP is applied to the elastic contractility body 11. After these operations are completed, the inflow control valve 13 and the outflow control valve 16 are closed.
In this state, the elastic contractile body 10 has Pa=P ₁ +
ΔP, a pressure of Pb=P ₁ −ΔP acts on the elastic contractile body 11, and the mass point 12 shifts to the right in FIG. 2 as described above, moves by a distance x, and then stops.

Letting F be the force that initially acts on the mass point 12 when it moves by x, it is sufficient to take the difference between each f in equation (1), so F=k ₁ (P ₁ +ΔP)−k ₂ (P ₁ +ΔP)εa−k ₁ (P ₁ −ΔP
)−k ₂ (P ₁ −ΔP)εb……(3) However, l ₀ is the natural length of the elastic contraction body, l is the length when the internal pressure of each elastic contraction body is P ₁ ,
FIG. 2 shows the state at _P1 . Further, for the sake of simplicity, the elastic contracting bodies are assumed to be the same.

Substituting equations (2) and (4) into equation (3) and rearranging, F=k _p ΔP−P ₁ k _x x ……(5) However, In the drive system shown in Fig. 2, Equation (5) becomes:
It represents the relationship between the force acting on the mass point 12, that is, the connecting portion 12 when the connecting portion 12 is deflected, the displacement distance thereof, and the pressure acting on the elastic contracting bodies 10 and 11. Also, in equation (5), F=0
When the value of x is , the connecting portion 12 stops and remains stationary.

Note that the present invention has been described using a linear drive device as an embodiment of the connecting portion driving method of the present invention.
The present invention can also be applied to a device for turning as shown in FIG. 4, or a device for controlling the force acting on a connecting portion. Although the inflow and outflow control valves may be provided directly on the elastic contractile body, it is more advantageous to use valves that are integrally formed with the mouthpiece, as this eliminates the problem of pressurized fluid supply piping.

(Effects of the Invention) According to the driving method of the present invention, the driving device electrically couples four electromagnetic flow control valves that control the flow rate by changing the coil voltage acting on the electromagnet. In comparison, it has excellent responsiveness and can control the position of the connecting part with an inexpensive device. Further, according to the present invention, the reference pressure of the two elastic contracting bodies can be changed with a simple configuration, and the compliance of the drive system can be easily changed as required under a stable state.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional linear drive device, Fig. 2 is a schematic diagram of a linear drive device that preferably implements the present invention, and Fig. 3 is an electromagnetic flow control suitable for use in the present invention. A cross-sectional view of the valve, FIG. 4, is a schematic diagram of a device implementing another embodiment of the invention. 1... Torque motor, 2, 3... Nozzle, 4...
...Flap valve, 5, 5... Throttle valve, 7, 8, 10,
11... Elastic contractile body, 9, 12... Mass point, 13,
14, 15, 16...Solenoid flow control valve, 17...
...Electromagnet, 18... Valve body, 19... Valve seat, 20...
...Nozzle section.

Claims (1)

[Claims] 1. A set of two elastic contracting bodies whose contraction amount is determined according to internal pressure are each provided with an inflow control valve and an outflow control valve, and each elastic contraction body is pressurized. When the connecting portion of the elastic contracting body is rotated and/or translated by the axial contractile force of the elastic contracting body generated by supplying and discharging fluid, prior to driving the connecting portion, each outflow control valve is activated. Under the closed state, each inflow control valve is opened, and each elastic contractile body is pressurized to a predetermined pressure, and then each inflow control valve is closed, and the connecting portion is elastically held at a predetermined position. Then, when driving the connecting part, the inflow control valve of one elastic contraction body is opened to increase the internal pressure of this elastic contraction body from the initial pressure, and at the same time, the outflow control valve of the other elastic contraction body is opened. Then, the internal pressure of this elastic contraction body is reduced by a pressure approximately corresponding to the pressure increase of the one elastic contraction body, and these control valves are closed, thereby holding the connecting portion elastically until it reaches a predetermined position. A method for driving a connecting portion of an elastic contracting body, characterized by rotating and/or translating and stopping the connecting portion.