JP2664534B2 - Position / force control device of actuator for shield moat machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position and force control device for an actuator for a shield machine used for moving a segment by an erector of the shield machine.

2. Description of the Related Art When a segment is automatically lined with an excavation hole excavated by a shield machine, if the segment is pressed with an excessive pressing force, a problem such as breakage of the segment occurs.

One prior art is disclosed in Japanese Society of Robotics, Vol. 8, No. 2, pp. 215-221, issued in April 1990. In this prior art, in order to automatically line a segment, when a mark previously formed on an existing lined segment is detected by an optical detection means, a segment to be newly lined is grasped. The movement of the grasping means is stopped, and the segment grasped by the grasping means is lined at a desired position.

Problems to be Solved by the Invention In such prior art, when lining a segment gripped by the gripping means, an excessive force is generated in the segment due to contact with the existing segment. As a result, the segment may be damaged.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position and force control device of an actuator for a shield machine which prevents an excessive force from acting when bringing a segment to a desired position.

Means for Solving the Problems The present invention provides (a) the gripping means 3 for gripping the segment 2 by displacing and driving the gripping means 3 in parallel with one diameter line of the shield machine 6 or the axis 7 of the shield machine 6; An actuator 1 for driving to turn around,
Actuator 1 having two drive rooms, and when hydraulic oil is supplied to one of the drive rooms, return oil is discharged from one of the other drive rooms; and (b) a position command value of the actuator 1 (C) a detector for detecting the position of the actuator 1; (d) a subtractor for subtracting the output of the electric signal source from the output of the detector; e) a hydraulic pressure source for supplying hydraulic oil; and (f) a pair of nozzles 24, 25 which are opposed to both sides of the flappers 22, 23, which are nozzle flapper type electric / hydraulic servo valves 16 and have a return spring force. The back pressure chambers 42 and 43 communicate with each other, and the operating oil that has exited from the nozzles 24 and 25 is led to a return oil passage, and the back pressure chambers 42 and 43 are operated via a throttle from a hydraulic source. Oil is supplied respectively, and a spool 30 is installed in the housing. The back pressure chambers 42, 43 communicate with operating chambers 28, 29 provided at intervals in the axial direction of the spool 30, respectively. Hydraulic oil is supplied to one of the drive chambers by being displaced in one axial direction, and the spool is
A hydraulic path is formed so that the hydraulic oil returns from the other drive chamber by displacing the axial direction 30 in the other direction, and both ends of the spool 30 face a pair of pressure control chambers 36, 38. One drive room is communicated by an oil passage 35 to one pressure control room 36 facing the one end of the spool 30 in the one axial direction, and the other drive room is connected to the other end of the spool 30 in the axial direction. The other pressure control chamber 38 facing the end in the direction is communicated by an oil passage 37, driven by the output of a subtractor, and one of the flappers 22, 23 is opposed to the return spring force. Nozzles 24, 25
And a coil flapper type electric / hydraulic servo valve 16 for discharging hydraulic oil to the actuator until the load is balanced by the load pressure of the actuator proportional to the output level of the subtractor. A position and force control device for an actuator for a shield machine.

According to the present invention, an actuator, for example, a hydraulic cylinder or a hydraulic motor, which is operated by hydraulic oil, is supplied with hydraulic oil from an electric / hydraulic servo valve, and receives a position command value from an electric signal generation source of the actuator. And an electric signal representing a subtraction value from the position detected by the detector of the actuator is supplied to the electric / hydraulic servo valve. In this electric / hydraulic servo valve, the load pressure is proportional to the electric signal level of the subtractor. As the hydraulic oil is discharged to the actuator until the balance is achieved, the object can be brought to a desired position by the actuator and the object can be brought to the position commanded by the position command value. Later, by changing the position command, it is possible to apply a force corresponding to the output of the subtractor, so that an excessive force acts Is prevented.

Embodiment FIG. 1 is a block diagram of one embodiment of the present invention. The actuator 1 in this embodiment is implemented in connection with the erector 2 of the shield machine shown in FIG.
Elector 2 is gripping means 3 for gripping segment 2
Is attached to an arm 4 and can be displaced by an elevating cylinder 5 in parallel to one diameter line of the shield machine body 6. The arm 4 is provided on a swivel ring 8 via the elevating cylinder 5, Numeral 8 can be angularly displaced around an axis 7 of the shield machine body 7 by a turning hydraulic motor 9. The actuator 1 in FIG. 1 is the lift cylinder 5 of the shield machine shown in FIG. 2, and may be a turning hydraulic motor 9 as another embodiment.

A position command signal, which is a position command value, is generated from a generation source 11 and is provided to one input of a subtractor 12. The position of the actuator 1, that is, the position of the arm 4 is detected by a position detector 13, and the detection output is given to the other input of the subtractor 12. The subtractor 12 subtracts each output of the source 11 and the detector 13 and supplies a signal representing the subtraction value to an amplifier circuit 14 to perform amplification or various compensation operations,
15 to the electric / hydraulic servo valve 16 This servo valve 16
Is supplied to the actuator 1 through the pipe 17.

FIG. 3 is a sectional view of the electric / hydraulic servo valve 16. This electric / hydraulic servo valve basically has a structure in which a field back of load pressure is added to a so-called nozzle-flapper type flow-type servo valve. Chambers 42 and 43 communicate with a pressure source through a line with
It communicates with the return oilway through 4,25. A torque motor 19 is provided in the housing 18 and its coil 20 or
The current is supplied to 21 so that the flapper 22 or
23 is displaced to the left or right in FIG.
The back pressure of the nozzles 24 and 25 provided opposite to changes.
This nozzle back pressure is guided to rooms 28 and 29 via oil passages 26 and 27, and a spool 30 is provided in the rooms 28 and 29. One port 31 and the other port 32 are connected to chambers on both sides of the piston of the actuator 1, and these ports 31 and 32 are further connected to the chambers 33 and 34 in which the spool 30 is stored.
Is in communication with The port 31 is connected to a chamber 36 at one end of the spool 30 via an oil passage 35. Another port 32
Is connected to a chamber 38 at the other end of the spool 30 via an oil passage 37.

The aforementioned nozzle back pressure is guided to the chambers 28 and 29 of the spool 30, and a driving force for driving the spool 30 is generated by the differential pressure. When the spool 30 is displaced, the ports 31, 32
High pressure chamber (supply pressure) 39,40 or low pressure chamber (return pressure) 41,
Hydraulic paths are formed respectively, and hydraulic oil flows into the ports 31, 32, and the return spring force acting on the flappers 22, 23 causes the flappers 22, 23 to move in the direction of returning to the original position,
The difference of the nozzle back pressure is returned to zero, and the displacement of the spool 30 stops. Further, when the pressure of the actuator 1 on the load side changes due to the flow of the hydraulic oil to the ports 31 and 32, the hydraulic pressure of the ports 31 and 32 is guided to the chambers 36 and 38, The spool 30 is displaced by the differential pressure. Accordingly, when the differential pressure of the actuator 1 rises to a value corresponding to the nozzle back pressure, if there is no flow of hydraulic oil on the actuator 1 side, the ports 30 and 32 are closed by the spool 30 and the hydraulic oil stops flowing. When the pressure of the actuator 1 becomes higher than the nozzle back pressure equivalent value, the ports 30 and 32 are opened in the opposite direction by the spool 30 to move in the direction of decreasing the pressure of the actuator 1. In this way, the function of controlling the differential pressure between the two chambers of the actuator 1 and thus the two ports 31, 32 is achieved.

The configuration of the electric / hydraulic servo valve 16 will be further described with reference to FIG. The pair of nozzles 24 and 25 are provided opposite to both sides (both sides in the left-right direction of FIG. 3) of the flappers 22 and 23 having the returning spring force as described above. 42 and 43 communicate with each other. The rooms 28 and 29 are provided at intervals in the axial direction of the spool 30 (the left-right direction in FIG. 3). Both ends of the spool 30 face the rooms 36 and 37.

When the actuator is a cylinder, the cylinder has two driving chambers, a chamber on the cylinder head side and a chamber on the piston rod side, and hydraulic oil is supplied to one of these two chambers. When supplied, return oil is discharged from one of the other driving chambers, and such a configuration is the same in a hydraulic motor.

FIG. 4 is a graph showing characteristics of the electric / hydraulic servo valve 16. The horizontal axis indicates the load pressure PL, and the vertical axis indicates the discharge flow rate Q of the working oil supplied to the actuator 1. Characteristics l1, l2, and l3 are obtained corresponding to currents i1, i2, and i3 (i1 <i2 <i3) supplied to coils 20, 21 of torque motor 19, respectively.
The same applies when the load pressure is negative. The electric / hydraulic servo valve 16 discharges hydraulic oil to the actuator 1 until the current supplied from the amplifier circuit 14 to the coils 20 and 21 of the torque motor 19 via the line 15, for example, the load pressure corresponding to i3, At the load pressure PL3 proportional to the servo current i3, the discharge flow rate becomes zero and balance occurs.

The operation of the embodiment shown in FIGS. 1 to 4 will be described with reference to FIG. The object 40 is displaced by the actuator 1. This object 40 includes the segment 2, the gripping means 3 and the arm 4 of the shield machine shown in FIG. In a range until the segment 2 hits the segment 2a which is a work object lined with the existing drilling hole, the control system shown in FIG. 1 establishes a field back system related to displacement, and operates as a displacement control system. Is performed. That is, the difference between the electric signal representing the position command value from the generation source 11 and the output detected by the position detector 13 of the actuator 1 is calculated by the subtractor 12, and the amplification circuit 14
And the electric signal is amplified by the electric / hydraulic servo valve.
The coils 20 and 21 of the torque motor 19 are driven by the motor 16 and the actuator 1 operates accordingly. Thus, the object 40 can be brought to a desired position.

Segment 2 gripped by gripping means 3
In order to abut the existing segment 2a and press the segment 2a against the inner peripheral surface of the excavation hole, it is necessary to generate a force to the outside by the actuator 1. In FIG. 5 (2), the electric signal representing the position command value from the generation source 11 increases with the passage of time after the contact time t1, and in response to this, the object 40 is actuated by the actuator 1. It is displaced as shown in FIG. 5 (3). The actuator 1 displaces the object 40 until the segment 2 forming a part of the object 40 contacts the existing segment 2a at time t1, for example.
Actuator 1 as shown in FIG.
As a result, no pressing force is applied.

When it becomes necessary to press the segment 2 against the existing segment 2a, for example, the electric signal representing the position command value from the generation source 11 is further increased after time t1 in order to generate the pressing force by the actuator 1. As a result, a servo current commensurate with the displacement error is output from the arithmetic unit 12 via the line 15, so that the actuator 1 is driven by the servo valve 16 to generate a force to the outside. Will be. The current value given from the line 15 of the servo valve 16 is such that the force by the actuator 1 is made excessive by limiting the position command signal to a predetermined value i3 while keeping the position command signal constant after time t2. Can be prevented.

The invention can be implemented not only in connection with the lifting cylinder 5 as the actuator 1 but also for controlling the torque of the turning hydraulic motor 9.

As described above, according to the present invention, the actuator is supplied with hydraulic oil from the electric / hydraulic servo valve, and is detected by the actuator position command value from the electric signal generation source and the detector of the actuator. A signal representing a subtraction value from the subtracted position by the subtractor is provided to the electro-hydraulic servo valve, and the electro-hydraulic servo valve supplies the hydraulic oil until the hydraulic oil is balanced at a load pressure proportional to the electric signal level of the subtractor. Since the discharge is performed to the actuator, the object moved by the actuator is brought to the position specified by the position command value, and the load pressure by the actuator is converted to the position command value of the electric signal generating source. Corresponding settings can be made, so that excessive pressure on the object can be prevented.

According to the present invention, the pressure acting on the actuator 1 such as a cylinder or a hydraulic motor does not exceed the pressure corresponding to the current supplied to the coils 19 and 21 of the nozzle flapper type electric / hydraulic servo valve 16, and accordingly. Accurate position and pressure control can be achieved with a simple configuration.

In particular, according to the present invention, the gripping means 3 is driven by the actuator to be displaced parallel to one diameter line of the shield machine body 6, or is pivotally driven around the axis 7 of the shield machine body 6. In segment 2 near the position determined by the position command value, the value obtained from the subtractor of the electric signal representing the position command value output from the electric signal generation source and the output of the detector is small. Since there is no excessive force acting, segment 2
There is no problem such as damage.

After the segment 2 abuts the already lined segment, for example, near the position determined by the position command value, the position command value is changed to a desired appropriate value corresponding to the output of the subtractor. It is also possible for the segments to abut by force, as mentioned in the previous section of the operation.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a perspective view of an erector 2 of a shield machine, FIG. 3 is a sectional view of an electric / hydraulic servo valve 16, and FIG. FIG. 5 is a graph showing characteristics of the valve 16, and FIG. 5 is a diagram for explaining the operation of the embodiment shown in FIGS. DESCRIPTION OF SYMBOLS 1 ... Actuator, 2 ... Elector, 11 ... Electric signal generation source, 12 ... Subtractor, 13 ... Displacement detector, 14 ... Amplification circuit, 16 ... Electric / hydraulic servo valve

Continuation of the front page (56) References JP-A-61-206802 (JP, A) JP-A-1-216101 (JP, A) JP-A-51-51680 (JP, A) JP-A-53-56482 (JP) JP-A-53-22996 (JP, A) JP-A-63-23004 (JP, A) JP-B-33-6029 (JP, B1) JP-T2-504297 (JP, A)

Claims (1)

(57) [Claims] (A) for displacing and driving the gripping means 3 for gripping the segment 2 in parallel with one diameter line of the shield machine 6 or for turning around the axis 7 of the shield machine 6; Actuator 1 of 2
Actuator 1 having two drive rooms, and when hydraulic oil is supplied to one of the drive rooms, return oil is discharged from one of the other drive rooms; and (b) a position command value of the actuator 1 (C) a detector for detecting the position of the actuator 1; (d) a subtractor for subtracting the output of the electric signal source from the output of the detector; e) a hydraulic pressure source for supplying hydraulic oil; and (f) a pair of nozzles 24, 25 which are opposed to both sides of the flappers 22, 23, which are nozzle flapper type electric / hydraulic servo valves 16 and have a return spring force. The back pressure chambers 42 and 43 communicate with each other, and the operating oil that has exited from the nozzles 24 and 25 is led to a return oil passage, and the back pressure chambers 42 and 43 are operated via a throttle from a hydraulic source. Oil is supplied respectively, and a spool 30 is installed in the housing. The back pressure chambers 42, 43 communicate with operating chambers 28, 29 provided at intervals in the axial direction of the spool 30, respectively. Hydraulic oil is supplied to one of the drive chambers by displacement in one axial direction, and the spool 30
The hydraulic path is formed so that the hydraulic oil returns from the other drive chamber by being displaced in the other direction in the axial direction, and both ends of the spool 30 face a pair of pressure control chambers 36, 38, One drive chamber is communicated by an oil passage 35 to one pressure control chamber 36 facing the end of the spool 30 in the one axial direction, and the other drive chamber is in the other axial direction of the spool 30. The other pressure control chamber 38 facing the end is connected by an oil passage 37 and driven by the output of a subtractor, and the flappers 22 and 23 are driven by one of them against the return spring force. A coil flapper type electro-hydraulic servo valve 16 having coils 19, 21 displaced to the nozzles 24, 25 and discharging hydraulic oil to the actuator until the load is balanced by the load pressure of the actuator proportional to the output level of the subtractor. A seal characterized by including Position and force control device of the actuator for the excavator.