JP4121919B2 - Expansion / contraction structure and control device for expansion / contraction structure - Google Patents

Description

  The present invention relates to an expansion / contraction structure used as a linear motion actuator having flexibility for driving a mechanical structure such as a robot arm, and a control device for the expansion / contraction structure.

  In recent years, home robots such as pet robots have been actively developed, and it is expected that more practical home robots such as housework support robots will be put into practical use in the future. Since the home robot needs to enter the home and live together with humans, the required specifications are different from those of conventional industrial robots.

  In industrial robots, an electric motor and a speed reducer are used, and high hand position accuracy such as 0.1 mm repeatability is realized by high gain feedback control. However, a mechanism driven by such an electric motor has high rigidity and often lacks softness, and there are many problems in terms of safety.

  On the other hand, a home robot does not necessarily require a high accuracy such as a repeat accuracy of 0.1 mm, and safety is emphasized such that no harm is caused when it comes into contact with a human. Therefore, a mechanism driven by an electric motor like a conventional industrial robot cannot be said to be suitable for a field where safety is important, such as a home robot, and a flexible and safe driving mechanism is required. Yes.

  In response to such problems, a Macchiben type pneumatic actuator shown in FIG. 14 has been proposed. In the McKibben pneumatic actuator, a restraining member 54 made of a fiber cord is disposed on the outer surface of a tubular elastic body 53 made of a rubber material, and both ends of the tubular elastic body 53 are sealed by sealing members 55. The structure is hermetically sealed. When an internal pressure is applied to the inner space of the tubular elastic body 53 by supplying a compressive fluid such as air through the tubular fluid passage members 56, the tubular elastic body 53 tends to expand mainly in the radial direction. By the action of the restraining member 54, the tubular elastic body 53 is converted into a movement in the central axis direction, and the entire length contracts. Since this McKibben type actuator is mainly composed of an elastic body, it has a feature that it is a flexible, safe and lightweight actuator (for example, see Patent Document 1).

JP 59-197605 A

  However, since the McKibben type actuator generates displacement by injecting and extracting the compressive fluid into the tubular elastic body 53, it takes time to inject and extract the compressive fluid, and thus the response is poor. There is a problem that the linearity of the relationship between the internal fluid pressure and the displacement is poor, or there is a nonlinearity such as hysteresis, and it is difficult to drive with high precision.

  An object of the present invention is to solve the problems of the conventional structure described above, and to achieve expansion and contraction that realizes an expansion / contraction structure that is flexible, capable of large displacement, capable of high-speed response, and can be controlled with high accuracy. An object of the present invention is to provide a control device for a structure and an expansion / contraction structure.

  In order to achieve the above object, the present invention is configured as follows.

Moreover, according to the present invention, a hollow elastic body,
A sealing member that hermetically seals both ends of the hollow elastic body;
A fluid pressure drive cylinder disposed in series with the hollow elastic body and having a displacement amount by pressurization of fluid different from that of the hollow elastic body;
A tubular fluid passage member having a flow path through which the fluid passes, and allowing the fluid to pass through the flow path to inject or dispense fluid into the hollow elastic body and the fluid drive cylinder; An expansion / contraction structure is provided.

Further, according to the present invention, the expansion / contraction structure having a plurality of driving units arranged in series and having different displacement amounts due to pressurization,
A feedback compensator for performing feedback control of the expansion and contraction structure;
A low-pass filter that receives a signal from the feedback compensator and removes a high-frequency component, and then outputs a signal to a drive unit having a long length among a plurality of drive units arranged in series in the expansion and contraction structure;
A high-pass filter that receives a signal from the feedback compensator and removes a low-frequency component, and then outputs a signal to a drive unit having a short length among a plurality of drive units arranged in series of the expansion / contraction structure. An expansion / contraction structure control device is provided.

Further, according to the present invention, the expansion / contraction structure having a plurality of driving units arranged in series and having different displacement amounts due to pressurization,
A feedforward compensator that performs feedforward control of a drive unit having a long length among a plurality of drive units arranged in series in the expansion and contraction structure;
There is provided a control device for an expansion / contraction structure including a feedback compensator for performing feedback control of a drive unit having a short length among a plurality of drive units arranged in series of the expansion / contraction structure.

According to the elastic expansion / contraction structure of the present invention, by arranging the hollow elastic body and the fluid pressure drive cylinder in series, an actuator capable of flexible and large displacement and capable of high-speed response can be realized. A flexible and safe robot capable of accurate positioning and track tracking can be realized.

  Further, according to the control device for the elastic expansion / contraction structure of the present invention, since the low-pass filter and the high-pass filter are provided, unnecessary high-frequency components or low-frequency components of the control signal are removed. Response delay and saturation of the operation of the elastic structure are suppressed, and highly accurate control is possible.

  Further, according to the control device for an elastic expansion / contraction structure of the present invention, the feed-forward compensator and feed-back control by the feedback compensator perform feedback control by the feed-forward compensator. Therefore, it operates to roughly follow the target trajectory regardless of the position error, and the shorter tubular elastic body operates to respond to the target trajectory with good response by feedback control. Therefore, the shorter tubular elastic body compensates for the movement, and high-precision control is possible as a whole.

  Before describing embodiments of the present invention in detail, various aspects of the present invention will be described below.

According to the first aspect of the present invention, a plurality of hollow elastic bodies arranged in series and having different displacement amounts due to pressurization,
A connected sealing member that connects the plurality of hollow elastic bodies arranged in series with each other, and performs hermetic sealing at the connection portion;
A set of sealing members for sealing both ends of the plurality of hollow elastic bodies arranged in series;
By having a flow path through which the fluid passes and the fluid passes through the flow path, the fluid can be injected or poured into the hollow interior of each of the plurality of hollow elastic bodies arranged in series. An expansion / contraction structure including a tubular fluid passage member is provided.

  According to the second aspect of the present invention, at least one of the hollow elastic bodies arranged in series is tubular, and extends radially in the outer peripheral portion of the tubular hollow elastic body in the axial direction. The expansion / contraction structure according to the first aspect is provided, which includes a deformation direction restricting member that restricts deformation in the axial direction so as to contract in the radial direction and extend in the axial direction while contracting.

  According to a third aspect of the present invention, there is provided the expansion / contraction structure according to the first aspect, wherein at least one of the plurality of hollow elastic bodies arranged in series is a bellows-like hollow elastic body.

According to the fourth aspect of the present invention, a hollow elastic body,
A partition that divides the internal space of the hollow elastic body into two or more spaces of different volumes;
A set of sealing members for sealing both ends of the hollow structure;
The fluid has a flow path through which the fluid passes through the flow path, so that the fluid is injected or poured into each of the two or more spaces of the hollow structure divided by the partition wall. An expansion / contraction structure including a tubular fluid passage member that can be provided is provided.

  According to the fifth aspect of the present invention, in the hollow elastic body, at least one of the portions divided by the partition wall is tubular, and a deformation direction restricting member for restricting the deformation direction is disposed. An expansion / contraction structure according to a fourth aspect is provided.

  According to a sixth aspect of the present invention, the hollow elastic body provides the expansion / contraction structure according to the fourth aspect, wherein at least one of the portions divided by the partition wall has a bellows shape.

According to the seventh aspect of the present invention, a hollow elastic body,
A sealing member that hermetically seals both ends of the hollow elastic body;
A fluid pressure drive cylinder disposed in series with the hollow elastic body and having a displacement amount by pressurization of fluid different from that of the hollow elastic body;
A tubular fluid passage member having a flow path through which the fluid passes, and allowing the fluid to pass through the flow path to inject or dispense fluid into the hollow elastic body and the fluid drive cylinder; An expansion / contraction structure is provided.

  According to an eighth aspect of the present invention, there is provided the expansion / contraction structure according to the first aspect, the fourth aspect, or the seventh aspect, wherein the fluid is a compressive fluid.

According to the ninth aspect of the present invention, an expansion / contraction structure having a plurality of drive units arranged in series and having different displacement amounts due to pressurization;
A first feedback compensator for performing feedback control of a drive unit for a large displacement having a long length among a plurality of drive units arranged in series in the expansion and contraction structure;
Provided is a control device for an expansion / contraction structure including a second feedback compensator that performs feedback control of a short displacement drive unit among a plurality of drive units arranged in series in the expansion / contraction structure. To do.

According to the tenth aspect of the present invention, an expansion / contraction structure having a plurality of drive units arranged in series and having different displacement amounts due to pressurization,
A feedback compensator for performing feedback control of the expansion and contraction structure;
A low-pass filter that receives a signal from the feedback compensator and removes a high-frequency component, and then outputs a signal to a drive unit having a long length among a plurality of drive units arranged in series in the expansion and contraction structure;
A high-pass filter that receives a signal from the feedback compensator and removes a low-frequency component, and then outputs a signal to a drive unit having a short length among a plurality of drive units arranged in series of the expansion / contraction structure. An expansion / contraction structure control device is provided.

According to the eleventh aspect of the present invention, an expansion / contraction structure having a plurality of drive units arranged in series and having different displacement amounts due to pressurization,
A feedforward compensator that performs feedforward control of a drive unit having a long length among a plurality of drive units arranged in series in the expansion and contraction structure;
There is provided a control device for an expansion / contraction structure including a feedback compensator for performing feedback control of a drive unit having a short length among a plurality of drive units arranged in series of the expansion / contraction structure.

  Embodiments according to the present invention will be described below in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a configuration of an elastic expansion / contraction structure 1 according to the first embodiment of the present invention. In FIG. 1, 2 is a 1st tubular elastic body which is comprised with a rubber material and functions as a drive part. 3 is a knitted resin or metal fiber cord which is hardly stretched in terms of material, and the radial deformation caused by the expansion of the first tubular elastic body 2 is converted into the contraction of the length in the axial direction. A deformation direction restricting member in which the deformation in the radial direction due to the contraction of the tubular elastic body 2 is converted into the expansion of the axial length, and is arranged so as to cover the outer surface of the first tubular elastic body 2. Reference numeral 4 denotes a second tubular elastic body which is made of a rubber material and functions as a driving unit and has a shorter axial length than the first tubular elastic body 2. 5 is a material in which a fiber cord made of resin or metal that is difficult to stretch is knitted in a mesh shape, and the deformation in the radial direction due to the expansion of the second tubular elastic body 4 is converted into the contraction of the length in the axial direction. A deformation direction restricting member in which the deformation in the radial direction due to the contraction of the tubular elastic body 4 is converted into the expansion of the axial length, and is arranged so as to cover the outer surface of the second tubular elastic body 4. Reference numeral 6 denotes a first sealing member for sealing one end of the first tubular elastic body 2, and includes two parts, that is, an inner sealing part 6a and an inner sealing part 6a in which the inside is a fluid flow path. It seals by pinching the edge part of the 1st tubular elastic body 2 with the outer side sealing component 6b which cooperates and seals. Reference numeral 7 denotes a second sealing member for sealing one end of the second tubular elastic body 4, and two parts, that is, an inner sealing part 7a and an inner sealing part 7a, in which the inside is a fluid flow path, and It seals by pinching the edge part of the 2nd tubular elastic body 4 with the outer side sealing part 7b which cooperates and seals. 8 is a connection sealing member that connects the first tubular elastic body 2 and the second tubular elastic body 4 in series and seals the ends of the first tubular elastic body 2 and the second tubular elastic body 4; Four parts, that is, inner sealing part 8a in which the inside is a fluid flow path, outer sealing part 8b that cooperates with inner sealing part 8a, and inner sealing part 8d cooperates The outer sealing component 8c for sealing and the inner sealing component 8d having a fluid flow path inside, and the end portions of the first tubular elastic body 2 and the second tubular elastic body 4 It seals by inserting | pinching. 9a and 9b are tubular fluid passage members, the inside of which is a fluid flow path through which the fluid passes, and each of the first tubular elastic body 2 and the second tubular elastic body 4 arranged in series. The fluid can be injected or dispensed into the hollow interior of the first sealing member 6, and disposed inside the inner sealing component 6 a of the first sealing member 6 and the inner sealing component 7 a of the second sealing member 7. In addition, the 1st tubular elastic body 2 and the 2nd tubular elastic body 4 are mutually connected in series by the axial direction by fitting the convex part of the inner side sealing component 8d to the recessed part of the inner side sealing component 8a. Yes.

  FIG. 2 is a diagram showing a configuration of an air pressure supply system for driving the elastic expansion / contraction structure 1 according to the first embodiment of the present invention with air as a compressible fluid. In other embodiments as well, a similar air pressure supply system is required for the elastic expansion / contraction structure, but since it is the same as FIG. 2, illustration and description thereof are omitted.

  In FIG. 2, 10 is an air pressure source such as a compressor, and 11 is an air pressure adjusting unit in which an air pressure filter 11a, an air pressure reducing valve 11b, and an air pressure lubricator 11c are combined. 12a and 12b are, for example, three-port flow rate proportional solenoid valves that control the flow rate by driving a spool valve or the like with the force of an electromagnet. Reference numeral 13 denotes a control computer constituted by, for example, a general personal computer, which is equipped with a D / A board 13a and outputs voltage command values to the three-port flow proportional solenoid valves 12a and 12b independently of each other. Thus, the flow rate of each air flowing through the fluid passage members 9a and 9b can be controlled independently. Of course, by outputting the voltage command value to the three-port flow rate proportional solenoid valves 12a and 12b in synchronization, the flow rates of the air flowing through the fluid fluid passage members 9a and 9b can be controlled in synchronization.

Next, the operation of the elastic expansion / contraction structure 1 shown in FIG. 1 will be described taking as an example the case where the air pressure supply system shown in FIG. 2 is configured. The high-pressure air generated by the air pressure source 10 is depressurized by the air pressure adjusting unit 11, adjusted to a constant pressure such as 6 atm, and supplied to the 3-port flow rate proportional solenoid valves 12a and 12b. The opening degree of each of the three-port flow proportional solenoid valves 12a and 12b is controlled in proportion to the voltage command value output from the control computer 13 via the D / A board 13a. In each of the three-port flow rate proportional solenoid valves 12a and 12b, when a positive voltage command value is input from the D / A board 13a, the state is indicated by A of the pneumatic circuit symbol and is elastic from the pneumatic source 10 side. The flow path to the expansion / contraction structure 1 side is opened, and air having a flow rate proportional to the absolute value of the voltage command value is supplied to the elastic expansion / contraction structure 1 side. On the other hand, in each of the three-port flow rate proportional solenoid valves 12a and 12b, when a negative voltage command value is input from the D / A board 13a, the state is indicated by B of the pneumatic circuit symbol, and the elastic expansion / contraction structure A flow path from the body 1 side to the atmospheric pressure side is opened, and an air flow having a flow rate proportional to the absolute value of the voltage command value is exhausted from the elastic expansion / contraction structure 1 side to the atmosphere. The airflow supplied from the three-port flow proportional solenoid valves 12a and 12b to the elastic expansion / contraction structure 1 side passes through the first sealing member 6 and the second sealing member 7 by the fluid passage member 9, and the first tubular shape. The inside of the elastic body 2 and the second tubular elastic body 4 is reached, and the internal pressure of the first tubular elastic body 2 and the second tubular elastic body 4 is generated. The first tubular elastic body 2 and the second tubular elastic body 4 expand due to the generated internal pressure. However, due to the restraining action (regulation action) of the fiber cords assembled in a mesh shape of the deformation direction restriction member 3 and the deformation direction restriction member 5. Then, the deformation in the radial direction due to the expansion is regulated and converted into the contraction of the length in the axial direction, and the entire length of the elastic expansion / contraction structure 1 is shortened as shown in FIG. On the other hand, if the air is exhausted from the three-port flow proportional solenoid valves 12a and 12b to the atmosphere and the internal pressures of the first tubular elastic body 2 and the second tubular elastic body 4 are reduced, the first tubular elastic body 2 and the second tubular elastic body 2 The expansion is canceled by the elastic force of the elastic body 4, and the entire length of the elastic expansion / contraction structure 1 is expanded. As a result, in FIG. 3, when it is considered that it is fixed at the boundary line R between the inner sealing component 8 a and the outer sealing component 8 b, the difference in the distance d ₁ at the right end of the second tubular elastic body 4 due to the expansion and contraction. respect is located in the left end of the first tubular elastic body 2 there is a difference of greater distance d ₂ than the distance d _1.

  Therefore, the elastic expansion / contraction structure 1 according to the first embodiment can function as a linear displacement actuator by supplying and controlling air pressure. Since the expansion / contraction amount is approximately proportional to the internal pressure of the elastic expansion / contraction structure 1, the control computer 13 controls the three-port flow proportional electromagnetic valves 12a and 12b as shown in FIG. By controlling the air flow rate, the entire length of the elastic expansion / contraction structure 1 can be controlled.

  Here, the feature of the elastic expansion / contraction structure 1 in the first embodiment according to the present invention is that a plurality of tubular elastic bodies of the first tubular elastic body 2 and the second tubular elastic body 4 are arranged in series. It is in. When the total length is long like the first tubular elastic body 2, since the internal volume is large, it takes time to inject and discharge the fluid, so the response is poor, and since the total length is long, there is a disadvantage that the non-linearity is large accordingly. However, since a large displacement can be obtained and the internal volume is large, there is an advantage that the compression effect of air is large and the flexibility with respect to the external force is large. On the other hand, when the total length is short like the second tubular elastic body 4, the displacement is small and the flexibility is low, but since the internal volume is small, the fluid injection does not take time and the response is good and the high-speed driving is possible. This has the advantage that it can be driven with high precision and has low nonlinearity. Therefore, the elastic expansion / contraction structure 1 according to the first embodiment of the present invention in which a plurality of tubular elastic structures of the first tubular elastic body 2 and the second tubular elastic body 4 are arranged in series is advantageous in each case. Is utilized, and has characteristics of large displacement, high flexibility, good responsiveness, and high accuracy. For example, when high responsiveness is required, air is supplied into the second tubular elastic body 4 to cause quick displacement, while when large displacement is required, the inside of the first tubular elastic body 2 It is possible to greatly displace by supplying air.

  FIG. 4 is a diagram showing a configuration when the elastic expansion / contraction structure according to the first embodiment of the present invention is applied to driving a robot arm with one degree of freedom. In FIG. 4, reference numeral 15 denotes a first link to which a fixed end that is one end is fixed, and reference numeral 16 denotes a second link whose one end is connected to a free end opposite to the fixed end of the first link. It is a link. The free end portion of the first link 15 and the one end portion of the second link 16 are rotatably connected to each other at the joint portion 17 by a rotary bearing so that relative rotation is possible. The joint portion 17 is provided with an encoder 18 which is a rotation angle sensor, and the rotation angle θ can be measured. Reference numerals 19 and 20 denote a first elastic expansion / contraction structure and a second elastic expansion / contraction structure each having the same structure as the elastic expansion / contraction structure 1 and performing the same functions and effects, respectively. The first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20 are rod-shaped support members 22a and 20a to 21d that are fixed to the fixed end of the first link 15 on both sides and fixed orthogonally by spherical joints 21a to 21d. 22b and a rod-like support 22c having a central portion fixed to one end of the second link 16 so as to be pivotally orthogonal to each other. The first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20 include first and second flow proportional solenoid valves 24a and 24b, respectively, similar to the three-port flow proportional solenoid valves 12a and 12b in FIG. In addition, third and fourth flow proportional solenoid valves 24c and 24d are connected to supply and exhaust high-pressure air to the first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20. That is, the first elastic expansion / contraction structure 19 is connected to the tubular elastic body 19a that functions as the drive unit of the longer one of the first elastic expansion / contraction structure 19, and the first flow proportional electromagnetic valve 24a is connected. The tubular elastic body 19b that is shorter and functions as the drive unit is connected to the second flow proportional solenoid valve 24b, and the tubular elastic body that functions as the longer one of the second elastic expansion and contraction structures 20 and as the drive unit. A third flow proportional solenoid valve 24c is connected to the body 20a, and a fourth flow proportional solenoid valve 24d is connected to the tubular elastic body 20b which functions as the drive unit, which is the shorter of the second elastic expansion / contraction structures 20. Thus, the respective contraction / extension operations are controlled. In the structure of FIG. 4, either the first elastic expansion / contraction structure 19 or the second elastic expansion / contraction structure 20 contracts by the action of the first to fourth flow rate proportional solenoid valves 24a, 24b, 24c, and 24d. On the other hand, when the other is extended, a force is applied through the support 22c to rotate the joint portion 17 so as to rotate. For example, in FIG. 4, when the first elastic expansion / contraction structure 19 side is expanded and the second elastic expansion / contraction structure 20 side contracts, the support 22c connected to the first elastic expansion / contraction structure 19 and the spherical joint 21a is shown. As a result, the upper end side moves to the right with respect to the joint portion 17, while the lower end side of the support 22 c connected by the two elastic expansion / contraction structure 20 and the spherical joint 21 c moves to the left with respect to the joint portion 17. The support body 22c rotates counterclockwise around the joint portion 17, and the second link 16 fixed to the support body 22c is positioned to the lower left with respect to the origin position along the axial direction of the first link 15. To move. Conversely, when the first elastic expansion / contraction structure 19 side contracts and the second elastic expansion / contraction structure 20 side expands, the upper end side of the support 22c connected to the first elastic expansion / contraction structure 19 by the spherical joint 21a is the joint. As a result, the lower end side of the support 22c connected to the two elastic expansion / contraction structures 20 and the spherical joint 21c moves to the right with respect to the joint 17, while moving to the left with respect to the portion 17. Rotates around the joint portion 17 in the clockwise direction, and the second link 16 fixed to the support 22c moves so as to be located in the upper left direction with respect to the origin position along the axial direction of the first link 15.

  FIG. 5 is a block diagram of a control system for controlling the movement of the antagonistic drive structure of FIG. Reference numeral 26 denotes a control computer corresponding to the control computer 13 and shows functions realized by the control computer 26. The control computer 26 obtains the joint angle error θe by taking the difference between the joint angle target value θd obtained from the target trajectory generating means 125 and the joint angle measurement value θ obtained by the encoder 18, and the joint angle error θe is obtained. Constitutes a feedback control system in which the PD compensators 25a and 25b are inputted, and the control outputs are outputted from the PD compensators 25a and 25b to the first to fourth flow proportional solenoid valves 24a to 24d. The control output from the PD compensator 25a is supplied to the first flow proportional solenoid valve 24a for the longer tubular elastic body 19a of the first elastic expansion / contraction structure 19 as a voltage command value by the D / A output of the control computer 26. The applied voltage command value with the sign inverted is applied to the third flow proportional solenoid valve 24c for the longer tubular elastic body 20a of the second elastic expansion / contraction structure 20. The control output from the PD compensator 25b is a voltage command value by the D / A output of the control computer 26, and the second flow proportional solenoid valve for the shorter tubular elastic body 19b of the first elastic expansion / contraction structure 19 is used. A voltage command value that is applied to 24 b and whose sign is inverted is applied to the fourth flow proportional solenoid valve 24 d for the shorter tubular elastic body 20 b of the second elastic expansion / contraction structure 20. In this way, the sign of the control output from the PD compensators 25a and 25b is reversed, and the third and fourth flow proportional solenoid valves 24c for driving the second elastic expansion / contraction structure 20 which is another elastic expansion / contraction structure. , 24d, the contraction / extension of the first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20 is reversed, and antagonistic driving is realized.

  As a method of generating θd executed by the target trajectory generating means 125, there is a method of storing in advance in a memory. As a method of storing in advance in the memory, there are a method of giving a coordinate value by a numerical value, a method of recording by teaching operation, and the like. The data to be stored includes a method of storing all θd and a method of storing all θd in a discontinuous manner and generating by interpolation calculation between them.

  Further, as another method of generating θd executed by the target trajectory generating means 125, the state of the external environment is recognized by a sensor or the like in an autonomous robot or the like without being stored in the memory, and according to the result, There is a method for generating the motion trajectory θd by itself. When it is stored in the memory, it can move only as planned, but this method enables flexible movement according to the situation.

  Here, in the control system shown in FIG. 5, the longer tubular elastic body 19a of the first elastic expansion / contraction structure 19 is controlled by the first flow proportional solenoid valve 24a based on the control output of the PD compensator 25a. In addition, the longer tubular elastic body 20a of the second elastic expansion / contraction structure 20 is controlled by the third flow proportional electromagnetic valve 24c, while the third flow proportional electromagnetic is controlled based on the control output of the PD compensator 25b. The short tubular elastic body 19b of the first elastic expansion / contraction structure 19 is controlled by the valve 24c, and the short tubular elastic body 20b of the second elastic expansion / contraction structure 20 is controlled by the fourth flow proportional electromagnetic valve 24d. Is a feature. In this way, the PD compensator 25a for the long tubular elastic bodies 19a and 20a and the PD compensator 25b for the short tubular elastic bodies 19b and 20b are arranged, and the long tubular elastic bodies 19a and 20a and the short tubular elastic body 19b and By adopting a structure in which 20b can be controlled independently, it is possible to perform control utilizing the characteristics of the long tubular elastic bodies 19a and 20a and the short tubular elastic bodies 19b and 20b. If the gain values of the PD compensator 25a and the PD compensator 25b are appropriately determined, a tubular elastic member can be used for a large movement of the bending angle θ of the first link 16 around the joint portion 17 with respect to the axial direction of the second link 15. The characteristic that the large portions 19a and 20a of the bodies 19 and 20 are capable of large displacement exhibits an effect, realizes a rough follow-up to the target angle value θd, and the remaining angle error θe is compensated for by the tubular elastic bodies 19 and 20 The characteristics of the high-speed response and high accuracy of the 20 short portions 19b and 20b are effective, thereby realizing finer and more accurate tracking.

  By connecting a plurality of the antagonistic drive structures shown in FIG. 4 in series so that the control system of FIG. 5 can cope with a plurality of antagonistic drives, a robot arm with multiple degrees of freedom can also be realized. FIG. 15 shows an example of a robot arm having four degrees of freedom. The elastic expansion / contraction structures 105 and 106, the elastic expansion / contraction structures 107 and 108, the elastic expansion / contraction structures 109 and 110, and the elastic expansion / contraction structures 111 and 112 are respectively connected to the elastic expansion / contraction structures 19 and 20. It corresponds.

  The four-degree-of-freedom robot arm has a first joint 101 that rotates forward and backward in a plane along the horizontal direction along the vertical axis with respect to the fixed wall 301, and a first joint that rotates forward and backward in a plane along the vertical direction. A second joint 102, a third joint 103 that rotates forward and backward between the second arm 308 and the first arm 311; and a first joint that rotates forward and backward between the first arm 311 and the hand 313. It consists of four joints 104.

In the first joint 101, circular supports 302, 302 are rotatably connected to both sides of a rotating shaft 303 whose upper and lower ends are rotatably supported by bearings 304 and 305 along the vertical direction, and elastic expansion and contraction is achieved. One end of each of the structures 105 and 106 (not shown because the elastic expansion / contraction structure 106 is disposed behind the elastic expansion / contraction structure 105) is connected to the fixed wall 301 and the other ends. The portion is connected to the support shaft 314 of each circular support 302. Thus, the antagonistic driving of the elastic expansion and contraction structure 105 and 106, the first arm 311 of the robot arm in the plane along the transverse direction to the vertical axis _{X 1} around the rotation shaft 303 of the first joint 101 and second arm 308 The hand 313 can be rotated forward and backward integrally. The upper bearing 305 is supported on the fixed wall 301 by a support bar 306.

  In the second joint 102, one end of the second arm link 308 is fixed to two circular supports 302, 302 fixed to both sides of the rotation shaft 303. Support members 309 and 309 corresponding to the support members 22a and 22b are orthogonally fixed to the circular support member 302 side of the second arm link 308, and the second arm link 308 has a At one end of the one-arm link 311, a support 310 corresponding to the support 22 c is fixed orthogonally. Elastic expansion and contraction structures 107 and 108 are connected between the support members 309 and 309 of the second arm link 308 and the support member 310 fixed to one end of the first arm link 311, and elastic expansion By the antagonistic driving of the contraction structures 107 and 108, the first arm 311, the second arm 308, and the hand 313 of the robot arm are integrated in a plane along the vertical direction around the horizontal axis of the support shaft 314 of the second joint 102. Rotate forward and reverse.

  In the third joint 103, elastic expansion / contraction structures 109 and 110 are connected between the support 310 along the second arm 308 and the supports 309 and 309, and the elastic expansion / contraction structures 109 and 110 are antagonistic. By driving, the first arm 311 and the hand 313 are integrally rotated forward and backward in a plane along the vertical direction around the horizontal axis of the support shaft 315 of the third joint 103.

  In the fourth joint 104, elastic expansion / contraction structures 111 and 112 are connected between the support 310 along the first arm 311 and the support 312 fixed to one end of the hand 313, and elastic expansion / contraction is achieved. By the antagonistic drive of the structures 111 and 112, the hand 313 is rotated forward and backward in the plane along the vertical direction around the horizontal axis of the support shaft 315 of the third joint 103.

  As in the previous embodiment, each of the elastic expansion / contraction structures 105 and 106, the elastic expansion / contraction structures 107 and 108, the elastic expansion / contraction structures 109 and 110, and the elastic expansion / contraction structures 111 and 112 is the same as the first embodiment. To the fourth flow rate proportional solenoid valves 24a to 24c, and the four sets of first to fourth flow rate proportional solenoid valves 24a to 24c are connected to the control computer 26. The elastic expansion / contraction structures 105 and 106, the elastic expansion / contraction structures 107 and 108, the elastic expansion / contraction structures 109 and 110, and the elastic expansion / contraction structures 111 and 112 via the fourth flow rate proportional solenoid valves 24a to 24c. Control each contraction / extension motion.

  With the above structure, it is possible to realize basic functions as a robot arm, such as grasping and transporting an object, making use of multiple degrees of freedom.

Next, an operation simulation is performed in order to show the performance effectiveness of the elastic expansion / contraction structure according to the first embodiment of the present invention. Each characteristic of the first tubular elastic body or the second tubular elastic body can be approximately expressed by a transfer function of a quadratic response ((Kagawa, Fujita, Yamanaka, “Power assist circuit using artificial muscle actuator "The Journal of the Japan Society of Mechanical Engineers (C), 59-564 (1993-8), 2376-2382) That is, when the internal pressure P of the tubular elastic body is input and the contraction rate ε of the tubular elastic body is output. The transfer function G (s) of
G (s) = {f _p / ML ₀ } / {s ² + 2ζωs + ω ² }. . . . (1)
However,
f _p = (δF / δP) _ε0 . . . . (2)
f _ε = (δF / δε) _ε0 . . . . (3)
ω = √ (f _ε / ML ₀ ). . . . (4)
ζ = (C / 2ω). . . . (5)

F is the contraction force of the tubular elastic body, M is the load, L ₀ is the initial length of the tubular elastic body, and C is the viscous friction coefficient. s is a Laplace operator. The subscript _{ε0 in the} lower right of the above expressions (2) and (3) is the partial differential value in parentheses in the expressions (2) and (3) when the contraction rate ε is 0, that is, when the contracted and expanded body is a natural length. ("Partial differential value when shrinkage ratio ε = 0"). ω is a value represented by equation (4).

If the above equation is used, the operation characteristics of the elastic expansion / contraction structure can be simulated by the block diagram shown in FIG. FIG. 16 is a block diagram simulating the case where the length of the elastic expansion / contraction structure 1 of FIG. 1 is controlled by the control system configuration of FIG. In FIG. 16, 201 and 202 are feedback compensators, 203 and 204 are pressure conversion gains, 205 is a transfer function of the longer tubular elastic structure A of the elastic expansion / contraction structures, and 206 is an elastic expansion / contraction structure. It is a transfer function of the shorter tubular elastic structure B of the body. Reference numerals 207 and 208 denote conversion blocks for converting the contraction rates ε _A and ε _B of the tubular elastic structure A and the tubular elastic structure B to the full lengths of the tubular elastic structure A and the tubular elastic structure B. A value L obtained by adding the outputs of the conversion block 208 is the total length of the elastic expansion / contraction structure. However, the first sealing member 6, the second sealing member 7, and the connecting sealing member 8 are ignored because the length does not change.

FIG. 17 shows the result of simulation using the block diagram of FIG. In the simulation of FIG. 17, f _p = 5.0 × 10 ⁻⁴ [N / Pa], f _ε = 1000 [N], and C = 45 [Ns / m] from the measured values. Further, M = 1 [kg], and the initial length L ₀ of the elastic expansion / contraction structure was 0.5 [m].

The elastic expansion / contraction structure (a) in FIG. 17 is a case where the initial length L _0A of the tubular elastic structure A = 0.48 [m] and the initial length L _0B of the tubular elastic structure _B = 0.02 [m]. The feedback gains were K _LA = 900, K _vA = 7, K _LB = 1000, and K _vB = 3. The elastic expansion / contraction structure (b) in FIG. 17 is a case where the initial length L _0A of the tubular elastic structure A = 0.45 [m] and the initial length L _0B of the tubular elastic structure _B = 0.05 [m]. The feedback gains were K _LA = 520, K _vA = 7, K _LB = 1000, and K _vB = 4. The elastic expansion / contraction structure (c) in FIG. 17 is a case where the initial length L _0A of the tubular elastic structure A = 0.35 [m] and the initial length L _0B of the tubular elastic structure _B = 0.15 [m]. The feedback gains were K _LA = 1000, K _vA = 9.5, K _LB = 1000, and K _vB = 9.5. The elastic expansion / contraction structure (d) in FIG. 17 is the case where the initial length L _0A of the tubular elastic structure A = 0.25 [m] and the initial length L _0B of the tubular elastic structure _B = 0.25 [m]. The feedback gains were K _LA = 1000, K _vA = 9, K _LB = 1000, and K _vB = 9. Further, the expansion / contraction structure (e) in FIG. 17 is a step response in the case of the conventional example in FIG. 14, and the feedback gain is K _LA = 1000 and K _vA = 6.5. However, the feedback compensator 202, the pressure conversion gain 204, the pressure conversion gain 206, and the conversion block 208 are not used.

As can be seen from the simulation results of FIG. 17, according to the elastic expansion / contraction structures (a) to (d) according to the first embodiment of the present invention, the rise time is longer than that of the conventional expansion / contraction structure (e). Is short and excellent in responsiveness. The ratio of the length of the tubular elastic structure A and the tubular elastic structure B is the elastic expansion / contraction structure (b) when L _0A = 0.45 [m] and L _0B = 0.05 [m]. Most responsive. For example, the positioning accuracy at 0.015 [s] has a difference of about 2 mm between the elastic expansion / contraction structure (b) and the conventional expansion / contraction structure (e). Considering the structure of FIG. 4, when converted to an error of the angle θ assuming that the fulcrum length r is 50 mm, it is about 2 °. Assuming that the angle error is about 2 °, if the link length La of the first arm 311 and the link length Lb of the second arm 308 are both 300 mm in the case of the four-degree-of-freedom robot arm of FIG. When converted into an error, the level is 2 cm, and the difference between the elastic expansion / contraction structures (a) to (d) according to the first embodiment of the present invention and the conventional expansion / contraction structure (e) is large.

  As described above, according to the elastic expansion / contraction structure 1 according to the first embodiment of the present invention, a plurality of tubular elastic structures including the first tubular elastic body 2 having a long total length and the second tubular elastic body 4 having a short total length. Are arranged in series, the responsiveness is poor due to the first tubular elastic body 2, but a large displacement is obtained and the flexibility with respect to the external force is increased, while the second tubular elastic body 4 reduces the displacement and the flexibility. However, the response is good and high-speed driving is possible, the non-linearity is small, and high-precision driving is possible. As a result, the elastic expansion / contraction structure as a whole can realize an actuator that can be flexibly and largely displaced, can respond at high speed and can be driven with high accuracy, and can be a flexible and safe robot capable of high-accuracy positioning and trajectory tracking. It becomes feasible.

  In addition, according to the control device for the elastic expansion / contraction structure, the PD compensator 25a that controls the drive unit for a large displacement with a long length, and the PD that controls the drive unit for a small displacement with a short length. By arranging the compensator 25b and having a structure that can be controlled independently, it is possible to control the characteristics of the long tubular elastic bodies 19a and 20a and the short tubular elastic bodies 19b and 20b. If the gain values of the 25a and the PD compensator 25b are appropriately determined, the characteristic that the long portions 19a and 20a of the tubular elastic body can be displaced is effective for a large movement of the angle θ, and the target angle value is obtained. Achieves a rough follow-up to θd, and the remaining angle error θe is compensated by the characteristics of high-speed response and high accuracy of the short portions 19b and 20b of the tubular elastic body, thereby realizing finer and more accurate follow-up. You .

(Second Embodiment)
FIG. 6 is a block diagram of a control system for controlling the operation of the elastic expansion / contraction structure according to the second embodiment of the present invention. In the second embodiment, when the configuration shown in FIG. 1 as the elastic expansion / contraction structure is applied to the one-degree-of-freedom robot arm shown in FIG. 4 as an application example, the operation of the elastic expansion / contraction structure is controlled. The configuration of the control system is shown.

  In FIG. 6, 25 is one PD compensator, and 27 is a low pass filter (LPF), and the longer one of the first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20 is longer. It is connected to a first flow rate proportional solenoid valve 24a and a third flow rate proportional solenoid valve 24c that drive the tubular elastic bodies 19a and 20a, respectively. Reference numeral 28 denotes a high-pass filter (HPF) that is proportional to the second flow rate that drives the tubular elastic structures 19b and 20b having the shorter overall length of the first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20, respectively. The solenoid valve 24b and the fourth flow proportional solenoid valve 24d are connected. The configuration of the control system in the second embodiment is the same as that shown in FIG. 5 described above except that there is one PD compensator 25 and a low-pass filter 27 and a high-pass filter 28 are provided. Since the control system is the same as that of the first embodiment, members having the same functions as those in the first embodiment are denoted by the same reference numerals as those in FIG. 5 and description thereof is omitted.

  In the control system shown in FIG. 6, the low-pass filter 27 removes the high-frequency component of the control output signal, and only the low-frequency component that the tubular elastic structures 19a and 20a having the longer overall length that is inferior in response can sufficiently respond. It is set to pass. On the other hand, the high-pass filter 28 is set so as to remove low-frequency components of the control output signal that would saturate the expansion and contraction motions of the tubular elastic structures 19b and 20b having the shorter overall length, and to pass only the high-frequency components. Yes. Therefore, in the control system having the above configuration, response delay and saturation of the operation of the tubular elastic structure are suppressed, and highly accurate control is possible.

  As described above, according to the control system of the second embodiment, since the low-pass filter 27 and the high-pass filter 28 are provided, unnecessary high-frequency components or low-frequency components of the control signal are removed. Response delay and saturation of the operation of the structure are suppressed, and high-precision elastic expansion / contraction structure can be controlled, and a flexible and safe robot capable of high-precision positioning and track tracking can be realized.

(Third embodiment)
FIG. 7 is a block diagram of a control system for controlling the operation of the elastic expansion / contraction structure according to the third embodiment of the present invention. In the third embodiment, when the configuration shown in FIG. 1 as an elastic expansion / contraction structure is applied to the one-degree-of-freedom robot arm shown in FIG. 4 as an application example, the operation of the elastic expansion / contraction structure is controlled. The configuration of the control system is shown.

  In FIG. 7, reference numeral 29 denotes a feedforward compensator which drives the first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20 and the longer tubular elastic structures 19a and 20a. The flow rate proportional solenoid valve 24a and the third flow rate proportional solenoid valve 24c are connected. Reference numeral 30 denotes a PD compensator as a feedback compensator, which drives the tubular elastic bodies 19b and 20b having the shorter overall length of the first elastic expansion / contraction structure 19 and the second elastic expansion / contraction structure 20. It is connected to the 2 flow rate proportional solenoid valve 24b and the fourth flow rate proportional solenoid valve 24d, and constitutes a feedback control system. In the control system according to the third embodiment, other configurations are the same as those of the control system according to the first embodiment shown in FIG. 5 described above. Therefore, in FIG. The same reference numerals as those in FIG.

  In the control system shown in FIG. 6, the tubular elastic bodies 19a and 20a, which are capable of large displacement but are inferior in responsiveness and whose overall length is longer, are feedforward controlled by the feedforward compensator 29. Operates to follow the target trajectory. On the other hand, the tubular elastic bodies 19b and 20b, which are excellent in responsiveness and have a shorter overall length, operate so as to follow the target trajectory with good response by feedback control. Therefore, when the shorter tubular elastic bodies 19b and 20b compensate for the rough movement of the longer tubular elastic bodies 19a and 20a, high-accuracy control is possible as a whole.

  Next, an operation simulation is performed to show the effectiveness of the control system shown in FIG. 7 in terms of performance.

  FIG. 18 is a block diagram simulating a case where the length of the elastic expansion / contraction structure 1 of FIG. 1 is controlled by the control system configuration of FIG. In FIG. 18, reference numeral 209 denotes a feedforward compensator, and other configurations are the same as those in FIG.

FIG. 19 shows the result of simulation using the block diagram of FIG. In the simulation of FIG. 19, from the measured values, f _p = 5.0 × 10 −4 [N / Pa], f _ε = 1000 [N], and C = 45 [Ns / m]. Further, M = 1 [kg], and the initial length L ₀ of the elastic expansion / contraction structure was 0.5 [m].

The elastic expansion / contraction structure (a) of FIG. 19 has an initial length L _0A = 0.48 [m] of the tubular elastic structure A having the longer overall length, and an initial length L of the tubular elastic structure B having the shorter overall length. _This is a step response in the case of _0B = 0.02 [m], and gains were set to K _FF = 0.07, K _LB = 950, and K _vB = 3.2. Further, the elastic expansion / contraction structure (b) of FIG. 19 is a step response in the case of the conventional example of FIG. 14, and is the same result as the expansion / contraction structure (e) of FIG.

  As can be seen from the simulation results of FIG. 19, according to the elastic expansion / contraction structure (a) according to the third embodiment of the present invention, the rise time is shorter than the conventional expansion / contraction structure (e), and the response Excellent in properties.

  Further, according to the control device for an elastic expansion / contraction structure of the present invention, the feed-forward control by the feed-forward compensator 29 and the feedback control by the PD compensator 30 are performed, so that the tubular elastic bodies 19a and 20a having the longer overall length are performed. The feedforward compensator 29 operates to roughly follow the target trajectory regardless of the position error, and the shorter tubular elastic bodies 19b and 20b operate to respond to the target trajectory with good response by feedback control. The longer tubular elastic bodies 19a and 20b operate so as to compensate for the rough movement of the longer tubular elastic bodies 19a and 20a, and as a whole, highly accurate control becomes possible. Therefore, according to the control system of the third embodiment, the control of the elastic expansion / contraction structure with high accuracy is realized by the effect of the feedforward control and the feedback control, and the flexible and safe positioning and the tracking of the trajectory are possible. A simple robot can be realized.

(Fourth embodiment)
FIG. 8 is a diagram showing the configuration of the elastic expansion / contraction structure according to the fourth embodiment of the present invention. In FIG. 8, 31 is a tubular elastic body made of a rubber material. A partition wall 32 is disposed inside the tubular elastic body 31, and the internal space is divided into two spaces, that is, two portions 33a and 33b. Reference numeral 34 denotes a deformation direction restricting member in which a fiber cord is knitted in a mesh shape, and is arranged so as to cover the entire outer surface or almost the entire surface of the tubular elastic body 31. 35 and 36 correspond to the first sealing member 6 and the second sealing member 7 of the elastic expansion / contraction structure 1 of the first embodiment, and are sealing members that seal the ends of the tubular elastic body 31; Two parts 35a and 35b, that is, an inner sealing part 35a that is a fluid flow path through which fluid passes, and an outer sealing part 35b that cooperates with the inner sealing part 35a to perform sealing, and That is, each of the tubular elastic bodies 31 is formed by the inner sealing part 36a that is a fluid flow path through which the fluid passes and the outer sealing part 36b that performs the sealing in cooperation with the inner sealing part 36a. It seals by inserting | pinching an edge part. 37a and 37b are fluid passage members corresponding to the fluid fluid passage members 9a and 9b of the elastic expansion / contraction structure 1 of the first embodiment, and the inside is a fluid flow path through which the fluid passes, The inner sealing component 35 a of the member 35 and the inner sealing component 36 a of the sealing member 36 are disposed. The outside of the two portions 33a and 33b divided by the partition wall 38 of the hollow tubular elastic body 31 restricts deformation corresponding to the deformation direction restricting member 3 or 5 of the elastic expansion / contraction structure 1 of the first embodiment. The deformation direction regulating member, in other words, a fiber cord made of resin or metal that is difficult to stretch in material is knitted in a mesh shape, and the radial deformation due to the expansion of the tubular elastic body 31 is converted into the contraction of the axial length. On the other hand, a deformation direction restricting member is arranged in which the deformation in the radial direction due to the contraction of the tubular elastic body 31 is converted into the expansion of the axial length. The two parts 33a and 33b are, for example, the longer tubular elastic body 2 and the shorter tubular elastic body 4 of the elastic expansion / contraction structure 1 or the long one of the first elastic expansion / contraction structure 19. This corresponds to the longer tubular elastic body 19a and the shorter tubular elastic body 19b, or the longer tubular elastic body 20a and the shorter tubular elastic body 20b of the second elastic expansion / contraction structure 20.

  According to the elastic expansion / contraction structure of the fourth embodiment of the present invention, the partition wall 32 is disposed inside the tubular elastic body 31, so that the internal space is divided into the two portions 33 a and 33 b, so that the first As in the case of the elastic expansion / contraction structure 1; 19; 20 in the embodiment, the same effects as when the plurality of tubular elastic bodies 2, 4; 19a, 19b; 20a, 20b are arranged in series are exhibited. Can do. Moreover, in the elastic expansion / contraction structure in the fourth embodiment, since the tubular elastic body 31 and the partition wall 32 can be integrally formed, there are also advantages that the number of parts is small and the manufacture is easy.

(Fifth embodiment)
FIG. 9 is a diagram showing a configuration of an elastic expansion / contraction structure according to the fifth embodiment of the present invention. In FIG. 9, reference numeral 38 denotes a bellows-like elastic body made of a rubber material. The structure of the elastic expansion / contraction structure in the third embodiment is a bellows instead of one hollow elastic body 4 of the plurality of hollow elastic bodies 2, 4 of the elastic expansion / contraction structure 1 of the first embodiment. 9 is the same as the structure of the elastic expansion / contraction structure 1 of the first embodiment shown in FIG. 1 described above except for the point that the bellows-like elastic structure 38 is disposed. Members having the same functions as those in the first embodiment are denoted by the same reference numerals as those in FIG.

The bellows-like elastic structure 38 has a bellows formed by an inner sealing part 7a having a fluid flow path through which the fluid passes and an outer sealing part 7b that cooperates with the inner sealing part 7a to perform sealing. Sealing is performed by sandwiching the right end portion of the elastic member 38, and sealing is performed in cooperation with the inner sealing component 8d and the inner sealing component 8d which are fluid passages through which the fluid passes. It is sealed by sandwiching the left end portion of the bellows-like elastic structure 38 by the outer sealing component 8c to be performed, and an air flow is injected into the bellows-like elastic structure 38 via the fluid passage member 9b, and the bellows-like elasticity. When the internal pressure of the structure 38 increases, the structure 38 expands due to an expansion action as shown in FIG. Further, the bellows-like elastic structure 38 contracts due to the restoring action by the elastic force of the bellows-like elastic structure 38 when the air flow is discharged through the fluid passage member 9b and the internal pressure thereof is reduced. As a result, in FIG. 10, when considered to be fixed by the boundary R between the inner sealing part 8a and the outer sealing part 8b, by the expansion and contraction, difference in distance d ₃ in the right end of the bellows-like elastic structure 38 relative is located, there is a difference of greater distance d ₄ than the distance d ₃ in the left end of the first tubular elastic body 2.

As described above, the point of expansion when the internal pressure of the bellows-like elastic structure 38 is increased is the structure of the tubular elastic bodies 2 and 4 and the deformation direction restricting members 3 and 5 of the elastic expansion / contraction structure 1 of the first embodiment. Is different and the operation is reversed. Therefore, when applied to a robot arm having one degree of freedom similar to that of FIG. 4, the shorter tubular elastic body 19b of the first elastic expansion / contraction structure 19 is used.
The bellows-like elastic structures 38, 38 are arranged in place of the shorter tubular elastic body 20b of the second elastic expansion / contraction structure 20, and the second flow proportional solenoid valve 24b ′ and the fourth flow proportional solenoid valve 24d. If air pressure is supplied to the bellows-like elastic body 38, the output from the PD compensator 39b is inverted as shown in FIG. 11, unlike FIG. 5 in the first embodiment.

  That is, FIG. 11 is a block diagram of a control system that controls the movement of the antagonistic drive structure when applied to a robot arm with one degree of freedom similar to that of FIG. Reference numeral 26 'denotes a control computer corresponding to the control computers 13 and 26, and shows functions realized by the control computer 26'. The control computer 26 ′ obtains the joint angle error θe by taking the difference between the joint angle target value θd obtained from the target trajectory generating means 125 and the joint angle measured value θ by the encoder 18 in the same manner as described above. The joint angle error θe is input to the PD compensators 39a and 39b, and the control outputs are output from the PD compensators 39a and 39b to the first to fourth flow rate proportional solenoid valves 24a, 24b ′, 24c ′, and 24d ′. The feedback control system is configured. The control output from the PD compensator 39a is a voltage command value from the D / A output of the control computer 26 ', and the first flow proportional solenoid valve 24a for the longer tubular elastic body 19a of the first elastic expansion / contraction structure 19 is used. Is applied to the third flow proportional electromagnetic valve 24c ′ for the longer tubular elastic body 20a of the second elastic expansion / contraction structure 20. Further, the control output from the PD compensator 39b is a voltage command value based on the D / A output of the control computer 26 ', and the fourth flow proportional solenoid valve 24d for the bellows-like elastic body 38 of the second elastic expansion / contraction structure 20 is used. The voltage command value that is applied to 'and reversed in sign is applied to the second flow proportional solenoid valve 24b' for the bellows-like elastic body 38 of the first elastic expansion / contraction structure 19. In this way, the sign of the control output from the PD compensators 39a and 39b is reversed, and the second and third flow proportional solenoid valves 24b ′ for driving the bellows-like elastic bodies 38 of the elastic expansion / contraction structures 19 and 20 respectively. 24c ′, the longer tubular elastic body 19a of the first elastic expansion / contraction structure 19 and the long tubular elastic body 20a of the second elastic expansion / contraction structure 20, and the first elastic expansion / contraction structure The contraction / extension of the bellows-like elastic body 38 of 19 and the bellows-like elastic body 38 of the second elastic expansion / contraction structure 20 are reversed, and antagonistic driving is realized.

  In the fifth embodiment, the contraction of the bellows-like elastic body 38 is based on an elastic force. However, if suction is performed using an ejector (vacuum generator) or the like, higher speed driving is possible.

  Note that the bellows-like elastic structure 38 having the bellows shape described above is disposed in at least one of the two portions divided by the partition wall of the elastic expansion / contraction structure of the fourth embodiment. Good.

  As described above, according to the elastic expansion / contraction structure according to the fifth embodiment of the present invention, the plurality of tubular elastic structures including the first tubular elastic body having the long overall length and the bellows-like elastic body having the short overall length are arranged in series. Although the responsiveness is poor due to the first tubular elastic body, the displacement is small and the flexibility is low due to the bellows-like elastic body, while large displacement is obtained and the flexibility with respect to the external force is increased. Good high-speed driving is possible, non-linearity is small, and high-precision driving can be achieved. As a result, the elastic expansion / contraction structure as a whole can realize an actuator that can be flexibly and largely displaced, can respond at high speed and can be driven with high accuracy, and can be a flexible and safe robot capable of high-accuracy positioning and trajectory tracking. It becomes feasible.

(Sixth embodiment)
FIG. 12 is a diagram showing a configuration of an elastic expansion / contraction structure according to the sixth embodiment of the present invention. In FIG. 12, 40 is a cylinder tube formed of a metal cylinder, 41a and 41b are sealing members arranged so as to cover both ends of the cylinder tube 40, and 42 is fixed to the sealing member 41a and enters the cylinder tube 40. A fluid passage member having an internal structure in a fluid flow path through which the fluid passes to supply and exhaust the fluid, 43 is a piston that slides in the cylinder tube 40, and 44a is disposed in the sealing member 41a. An O-ring 44b is disposed on the piston 43 to seal the fluid between the outer peripheral surface of one end of the cylinder tube 40 and the sealing member 41a, and the fluid is connected between the inner peripheral surface of the cylinder tube 40 and the piston 43. An O-ring 44c is disposed on the sealing member 41b to seal the fluid between the outer peripheral surface of the other end of the cylinder tube 40 and the sealing member 41b. An O-ring 46 is fixed to the piston 43 at one end, and passes through the sealing member 41b so as to be able to advance and retreat. 45 is between the piston 43 and the sealing member 41b in the cylinder tube 40 and outside the piston rod 46. An elastic spring 44d arranged on the sealing member 41b is an O-ring that seals the fluid between the outer peripheral surface of the piston rod 46 and the sealing member 41b. 47 is a tubular elastic body made of a rubber material, and 48 is a knitted mesh of resin or metal fiber cords that are difficult to stretch, and the radial deformation caused by the expansion of the tubular elastic body 47 has an axial length. A deformation direction regulating member that is converted into contraction, and in which radial deformation caused by contraction of the tubular elastic body 47 is converted into expansion of the length in the axial direction, and is disposed so as to cover the outer surface of the tubular elastic body 47 Has been. Reference numeral 7 ′ denotes a first sealing member for sealing one end of the tubular elastic body 47, and two parts, that is, a fluid passage through which the fluid passes, and the other end of the piston rod 46 are fixed. The inner sealing component 7d and the outer sealing component 7c that cooperates with the inner sealing component 7d to seal the end portion of the tubular elastic body 47 are sealed. Reference numeral 49 denotes a second sealing member for sealing the other end of the tubular elastic body 47, and two parts, that is, an inner sealing part 49a and an inner sealing part, which are fluid passages through which the fluid passes. It seals by pinching the edge part of the tubular elastic body 47 with the outer side sealing part 49b which cooperates with the part 49a and seals. Reference numeral 50 b denotes a fluid passage member, and the inside thereof is a fluid flow path through which the fluid passes, and is disposed in the inner sealing component 49 a of the second sealing member 49. The cylinder tube 40, the piston rod 46, and the tubular elastic body 47 are arranged coaxially. The structure of the elastic expansion / contraction structure of the tubular elastic body 47 in the sixth embodiment is the same as the structure of the tubular elastic body of the elastic expansion / contraction structure 1 of the first embodiment shown in FIG. 12, tubular elastic body 47, deformation direction regulating member 48, first sealing member 7 ′, inner sealing component 7 d, outer sealing component 7 c, second sealing member 49, inner sealing component 49 a, outer sealing component 49b, the fluid passage member 50b, the second tubular elastic body 4, the deformation direction regulating member 5, the sealing member 8, the inner sealing component 8d, the outer sealing component 8c, the second sealing member 7, The inner sealing component 7a, the outer sealing component 7b, and the fluid passage member 9b are members having the same functions, and description thereof is omitted.

  The drive unit composed of the members 40 to 46 shown in FIG. 12 is a drive cylinder 340 having the same configuration as a single-acting pneumatic cylinder, and is arranged in series with the hollow elastic body 47 to provide fluid. The amount of displacement due to the pressurization is different from that of the hollow elastic body 47. When the inside of the cylinder tube 40 of the drive cylinder 340 is pressurized by fluid injection, the piston 43 is pushed and the piston rod 46 expands to the outside. On the other hand, when the inside of the cylinder tube 40 is depressurized by fluid extraction, the force of the elastic spring 45 overcomes, the piston 43 is pushed back, and the piston rod 46 contracts to the inside.

  According to the configuration of the elastic expansion / contraction structure in the sixth embodiment described above, the effect of large displacement by the same configuration as the pneumatic cylinder and the effect of high-speed response by the short-length tubular elastic body 47 and the deformation direction regulating member 48 are provided. Thus, an actuator capable of large displacement and high-speed response can be realized.

  In the sixth embodiment, the configuration is the same as that of the single-acting pneumatic cylinder, but the same effect is exhibited even in other cylinder structures such as a double-acting cylinder.

(Seventh embodiment)
FIG. 13 is a diagram showing a configuration of an elastic expansion / contraction structure according to the seventh embodiment of the present invention. In the first embodiment shown in FIG. 1, instead of the shorter second tubular elastic body 4 of the elastic expansion / contraction structure 1, the driving section is constituted by an electromagnet.

  In FIG. 13, 347 is an electromagnet, 348 is an electromagnet housing that houses the electromagnet 347 therein, and 349 is made of a magnetic material that is disposed inside the electromagnet 347 in the electromagnet housing 348 and connected to the inner sealing component 8a. Fixed iron core. Reference numeral 350 denotes a movable iron core that is disposed inside the electromagnet 347 in the electromagnet housing 348 and is made of a magnetic material. The central axis thereof is disposed on the same axis as the central axis of the fixed iron core 349 and is movable in the direction of the central axis. It has become. Reference numeral 351 denotes an elastic spring, which is disposed in the gap between the fixed iron core 349 and the movable iron core 350. A stopper 352 is fixed to one end of the electromagnet housing 348 and restricts the movable iron core 350 from being detached from the electromagnet housing 348.

  Since the other structure of the elastic expansion / contraction structure in the seventh embodiment is the same as the structure of the elastic expansion / contraction structure of the first embodiment shown in FIG. 1 already described, FIG. 13 shows the first embodiment. The members having the same functions as those shown in FIG.

  Next, the operation of the drive unit composed of the members 347 to 352 shown in FIG. 13 will be described. When current flows through the electromagnet 347 under the control of the control computer 13, the fixed iron core 349, which is a magnetic material, is magnetized by the magnetism generated by the electromagnet 347, and the movable iron core 350, which is a magnetic material, is attracted. Therefore, when the amount of current flowing through the electromagnet 347 is increased under the control of the control computer 13, the attractive force overcomes the elastic spring 351, and the entire length of the drive unit composed of the members 347 to 352 contracts (in other words, the right end of FIG. 13 is moved by suction in the left direction of FIG. 13, and as a result of the right end of the movable core 350 moving in the left direction, the entire length of the drive unit contracts). On the other hand, when the amount of current flowing through the electromagnet 347 is reduced under the control of the control computer 13, the entire length of the drive unit composed of the members 347 to 352 is extended by the restoring force of the elastic spring 351 (in other words, the right end of FIG. Since the determined movable iron core 350 moves in the right direction in FIG. 13 by the restoring force of the elastic spring 351, the right end of the movable iron core 350 moves in the right direction, so that the entire length of the drive unit extends).

  According to the configuration of the elastic expansion / contraction structure in the seventh embodiment described above, the right-side drive unit in FIG. 13 composed of the members 347 to 352 is driven by the electromagnet 347, so that the member is driven by fluid pressure. That is, a higher-speed response is possible compared to the left drive unit shown in FIG. 13 composed of the first tubular elastic body 2 and the deformation direction restricting member 3, and the nonlinearity is also small. Therefore, an actuator capable of large displacement, high-speed response, and high-accuracy driving is achieved by the effect of large displacement due to the long-length tubular elastic body and the deformation direction regulating member and the effect of high-speed response and high linearity by electromagnet drive. realizable.

  In the seventh embodiment, the electromagnet drive is used. However, the present invention is not limited to this, and the same effect can be achieved by other electric drive methods such as a drive method using a piezoelectric element.

  In the first to sixth embodiments, the air pressure is taken as an example of the compressible fluid and described. However, the present invention is not limited to this, and other compressible fluids such as nitrogen exert the same effect. .

  Moreover, in the said 1st-6th embodiment, although it was set as the structure which consists of two drive parts, such as a combination of two tubular elastic bodies, a tubular elastic body, and a bellows-like elastic body, it is not necessarily restricted to this but three or more The same effect can be achieved even with a configuration comprising the drive unit.

  The application of the elastic expansion / contraction structure according to the present invention is not limited to the robot arm, but can be applied as a drive mechanism or a force buffer mechanism for other movable machine structures.

  In the above-described embodiment, the plurality of hollow elastic bodies serving as the plurality of drive units that are arranged in series and have different displacement amounts due to pressurization are not limited to those having the same inner and outer diameters (or the same inner diameter) and different overall lengths. Instead, like the hollow elastic bodies 2 and 4 ′ shown in FIG. 20, the total length may be the same, but the volume may be different due to the different inner diameter, and the displacement may be different.

  It is to be noted that, by appropriately combining arbitrary embodiments of the various embodiments described above, the respective effects can be achieved.

  The expansion / contraction structure and the control device for the expansion / contraction structure according to the present invention are configured so that a plurality of tubular elastic structures of the first tubular elastic body and the second tubular elastic body are arranged in series, so that flexible and large displacement can be achieved. It is possible to realize an actuator capable of high-speed response, a flexible and safe robot capable of high-accuracy positioning and track tracking, and a linear motion drive actuator that has the flexibility to drive a mechanical structure such as a robot arm. Useful as such.

It is sectional drawing which shows the structure of the elastic expansion / contraction structure in 1st Embodiment of this invention. It is a partial cross section figure which shows the structure of the air pressure supply system in 1st Embodiment of this invention. It is a side view which shows operation | movement of the elastic expansion / contraction structure in 1st Embodiment of this invention. It is a side view which shows the example of application of the elastic expansion-contraction structure in 1st Embodiment of this invention. It is a block diagram of the control system which controls operation | movement of the elastic expansion / contraction structure in 1st Embodiment of this invention. It is a block diagram of the control system which controls operation | movement of the elastic expansion / contraction structure in 2nd Embodiment of this invention. It is a block diagram of the control system which controls operation | movement of the elastic expansion / contraction structure in 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the elastic expansion / contraction structure in 4th Embodiment of this invention. It is sectional drawing which shows the structure of the elastic expansion / contraction structure in 5th Embodiment of this invention. It is a side view which shows operation | movement of the elastic expansion / contraction structure in 5th Embodiment of this invention. It is a block diagram of the control system which controls operation | movement of the elastic expansion-contraction structure in 5th Embodiment of this invention. It is sectional drawing which shows the structure of the elastic expansion / contraction structure in 6th Embodiment of this invention. It is a partial cross section figure which shows the structure of the elastic expansion / contraction structure in 7th Embodiment of this invention. It is sectional drawing which shows the structure of the conventional elastic expansion / contraction structure. It is a block diagram which shows the example made into the robot arm of 4 degrees of freedom. FIG. 3 is a block diagram simulating a case where the length of the elastic expansion / contraction structure of FIG. 1 is controlled by the control system configuration of FIG. 2. It is a graph which shows the result of the simulation using the block diagram of FIG. FIG. 3 is a block diagram simulating a case where the length of the elastic expansion / contraction structure of FIG. 1 is controlled by the control system configuration of FIG. 2. It is a graph which shows the result of the simulation using the block diagram of FIG. It is sectional drawing concerning the modification of the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic expansion-contraction structure 2 1st tubular elastic body 3 1st deformation direction control member 4 2nd tubular elastic body 5 2nd deformation direction control member 6 1st sealing member 6a Inner sealing component 6b Outer sealing component 7, 7 '2nd sealing member 7a Inner sealing component 7b Outer sealing component 8 Connection sealing member 8a Inner sealing component 8b Outer sealing component 8c Outer sealing component 8d Inner sealing component 9a, 9b Fluid passage member 10 Air pressure Source 11 Pneumatic pressure adjustment unit 12 3-port flow proportional solenoid valve 13 Control computer 14 D / A board 15 First link 16 Second link 17 Joint portion 18 Encoder 19, 19 'First elastic expansion / contraction structure 19a The longer overall length Tubular elastic body 19b Tubular elastic body 20, 20 ′ having a shorter overall length Second elastic expansion / contraction structure 20a Tubular elastic body 20b having a longer overall length 20b Tubular elasticity having a shorter overall length 21a-21d Spherical joint 22 Support body 23 Support body 24a, 24b, 24c, 24d; 24a, 24b ', 24c', 24d 'First to fourth flow rate proportional solenoid valves 25, 25a, 25b PD compensator 26, 26' Control computer 27 Low pass filter 28 High pass filter 29 Feed forward compensator 30 PD compensator 31 Tubular elastic structure 32 Partition 33 Internal space 34 Deformation direction regulating member 35 Sealing member 36 Sealing member 37 Fluid passage member 38 Bellows-like elastic structure 39a, 39b PD compensator 40 Cylinder tube 41a, 41b Seal member 42 Fluid passage member 43 Piston 44a, 44b, 44c, 44d O-ring 45 Elastic spring 46 Piston rod 47 Tubular elastic body 48 Deformation direction regulating member 49 Second seal Member 49a Inner sealing part 4 9b Outer sealing component 50b Fluid passage member 347 Electromagnet 348 Electromagnet housing 349 Fixed iron core 350 Movable iron core 351 Elastic spring 352 Stopper 53 Tubular elastic body 54 Restraining member 55 Sealing member 56 Fluid passage member

Claims (3)

A hollow elastic body;
  A sealing member that hermetically seals both ends of the hollow elastic body;
  A fluid pressure drive cylinder disposed in series with the hollow elastic body and having a displacement amount by pressurization of fluid different from that of the hollow elastic body;
  A tubular fluid passage member having a flow path through which the fluid passes, and allowing the fluid to pass through the flow path to inject or dispense fluid into the hollow elastic body and the fluid drive cylinder; An expansion / contraction structure comprising: An expansion / contraction structure having a plurality of driving units arranged in series and having different displacement amounts due to pressurization;
  A feedback compensator for performing feedback control of the expansion and contraction structure;
  A low-pass filter that receives a signal from the feedback compensator and removes a high-frequency component, and then outputs a signal to a drive unit having a long length among a plurality of drive units arranged in series in the expansion and contraction structure;
  A high-pass filter that receives a signal from the feedback compensator and removes a low-frequency component, and then outputs a signal to a drive unit having a short length among a plurality of drive units arranged in series of the expansion / contraction structure. An expansion / contraction structure control device. An expansion / contraction structure having a plurality of driving units arranged in series and having different displacement amounts due to pressurization;
  A feedforward compensator that performs feedforward control of a drive unit having a long length among a plurality of drive units arranged in series in the expansion and contraction structure;
  A control device for an expansion / contraction structure comprising a feedback compensator for performing feedback control of a drive unit having a short length among a plurality of drive units arranged in series in the expansion / contraction structure.

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