Hybrid driver based on intelligent material

Abstract

The invention relates to a hybrid driver based on an intelligent material. The hybrid driver comprises a fixed support, a PAM driving module, an SMA driving module and a switching device. The fixing support is composed of an upper-layer support and a lower-layer support, the SMA driving module and the switching device are installed on the upper layer, and the PAM driving module is installed on the lower layer. The PAM driving module comprises an extension type PAM, a pneumatic proportional valve and an air compressor; the SMA driving module comprises three same SMA wires, a front end fixed pulley, a rear end fixed pulley, a fixing device A, a fixing device B, a front end spring, a rear end spring, a nylon rope, a steel wire rope and a power supply; the switching device comprises a guide rail sliding block mechanism, a fixing device B, a fixing device C, a front end spring, a rear end spring, a nylon rope, a steel wire, a pneumatic push rod, a two-position five-way electromagnetic valve and a connecting device. And the switching device is connected with the PAM driving module and the SMA driving module. According to the invention, the large-range movement of the driver is realized through a PAM driving mode.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent material hybrid drivers, and in particular relates to a hybrid driver based on intelligent materials. Background Art

[0002] With the rapid development of robotics technology, especially the emergence of soft continuum robots, the actuators are required to have the characteristics of good flexibility and light weight, while also requiring them to have advantages such as high power density ratio, high integration, easy motion control, and variable stiffness. Thanks to the large output displacement and output force of pneumatic artificial muscle actuators, they are being widely used in the design of continuum manipulators. Although the continuum manipulator driven by pneumatic artificial muscle shows excellent range of motion and load capacity compared with other driving methods, due to the viscoelastic properties of the material, obvious hysteresis nonlinearity, and airflow flow, it is difficult for pneumatic driven manipulators to ensure precise positioning operations. The existing single flexible intelligent material actuators are difficult to meet the above requirements at the same time, and many researchers and scholars are focusing on hybrid actuators. However, the hybrid actuators currently available are mostly concentrated in the hybrid drive of motor-driven ropes or nylon wires and pneumatic artificial muscles, with a low level of integration and low power density. Limited by the size of the motor, the number of threads that can be arranged in the manipulator is limited, and the output force that can be provided is insufficient. Summary of the invention

[0003] The present invention provides a hybrid driver based on smart materials, and the specific technical solution is as follows:

[0004] A hybrid actuator based on smart materials, comprising a fixed bracket, a pneumatic artificial muscle driving module, a shape memory alloy driving module and a switching device; wherein PAM stands for pneumatic artificial muscle and SMA stands for shape memory alloy;

[0005] The fixed bracket includes an upper bracket, a lower bracket and a base; the base is in an I-shape, and the upper bracket and the lower bracket are constructed by combining aluminum profiles with the base;

[0006] The fixing device A is provided with a primary baffle, a secondary baffle, and a hexagonal copper column. The primary baffle is fixed to the upper bracket through an angle connector. The secondary baffle of the fixing device A is provided with three circular holes.

[0007] The left and right ends of the concave connector are fixed to the lower bracket through angle connectors;

[0008] The upper bracket is used to horizontally fix the SMA drive module and the switching device;

[0009] The lower bracket is used to vertically fix the PAM drive module;

[0010] The PAM drive module includes an elongated PAM, a pneumatic proportional valve and an air compressor; the air compressor provides an air source to the pneumatic proportional valve through an air pipe, and the pneumatic proportional valve provides the required air pressure to the elongated PAM through an air pipe;

[0011] The SMA drive module includes three identical SMA wires, a rear fixed pulley, a fixture A and a programmable power supply;

[0012] The left ends of the three SMA wires are fixed in parallel in the circular holes of the secondary baffle at the left end of the fixture A, and the right ends of the three SMA wires are fixed in parallel to the right end of the fixture C by passing the fixed pulley at the rear end. The power supply is connected to the SMA wires through wires to provide current for driving the SMA wires;

[0013] The switching device includes a guide rail slider, a pneumatic push rod, a flat nylon rope, a wire rope, a front fixed pulley, a fixing device B, a front spring, a rear spring and a two-position five-way solenoid valve;

[0014] The fixing device C is fixed to the guide rail slider by bolts;

[0015] The pneumatic push rod is fixed above the rectangular through hole of the fixing device C, and a pneumatic push rod patch is pasted on the end of the pneumatic push rod; the friction force can be increased so that the nylon rope and the pneumatic push rod will not slide relative to each other;

[0016] The right end of the fixing device C is provided with three edge circular holes connected to the left end of the SMA wire, and the left and right side walls of the fixing device C are respectively provided with rectangular through holes through which the flat nylon rope passes;

[0017] The guide rail slider is fixed to the upper bracket through a fixing device A, the pneumatic push rod is fixed above the guide rail slider through a fixing device C, the flat nylon rope passes through the gap between the end of the pneumatic push rod and the fixing device C, the left end of the flat nylon rope is connected to the upper end of the wire rope through the front fixed pulley, the lower end of the wire rope is connected to the lower end of the extended PAM, the right end of the flat nylon rope is connected to the left end of the rear end spring, the right end of the rear end spring is fixed to the fixing device B, the left and right ends of the front end spring are respectively connected to the left end of the fixing device A and the left end of the fixing device C, the two-position five-way solenoid valve is connected to the pneumatic push rod through the air pipe to provide an air source for the pneumatic push rod, the on and off of the two-position five-way solenoid valve realizes the pushing out and retracting of the pneumatic push rod, and completes the compression and release of the flat nylon rope, thereby realizing the PAM driving mode and the mixed driving mode of PAM and SMA.

[0018] The preferred embodiment of the hybrid drive based on smart materials is that the elongated PAM includes an upper end plug, a lower end plug, an inner rubber tube, an outer rubber tube, a braided mesh, a group A clamp and a group B clamp;

[0019] The centers of the upper end plug and the lower end plug have an integrated boss structure;

[0020] The two ends of the inner rubber tube are fixed between the two bosses by a group A of clamps;

[0021] The upper end plug has air holes for inlet and outlet air flow and a through hole for the wire rope to pass through, and the center of the boss of the lower end plug has an annular structure for fixing the wire rope;

[0022] The outer rubber tube is fixed between the upper plug and the lower plug, and the braided net is fixed between the upper plug and the lower plug by a group B clamp and is placed on the outer layer of the outer rubber tube;

[0023] The upper end plug is fixed on the concave connecting piece.

[0024] The provision of the inner rubber tube ensures good air tightness of the elongated PAM4 and avoids air leakage caused by the embedding of the steel wire rope.

[0025] The preferred solution of the hybrid drive based on smart materials is that the front spring is fixed to the outside of the front fixed pulley by a hexagonal copper column to avoid interference with the pulley movement.

[0026] A preferred solution of the hybrid driver based on smart materials is that the front spring is in a pre-stretched state and the rear spring is in a pre-stretched state.

[0027] A preferred solution of the hybrid drive based on smart materials is that the concave connector is 3D printed.

[0028] A hybrid actuator based on smart materials. When the pneumatic push rod is in the push-out state and the SMA wire is energized, the air pressure in the elongated PAM remains unchanged. The contraction of the SMA wire drives the fixing device C11 to move, thereby driving the movement of the nylon rope. The nylon rope transmits the force to the end of the elongated PAM through the steel wire rope, causing the end of the elongated PAM to move. At this time, the hybrid actuator can realize the hybrid drive of the elongated PAM and the SMA wire. The drive of the SMA wire is more stable than that of the elongated PAM. Due to the antagonistic effect of the output force of the elongated PAM and the SMA wire, the stiffness of the hybrid actuator can change with the change of the air pressure in the elongated PAM4 and the drive current of the SMA wire.

[0029] The hybrid actuator based on the elongated PAM and SMA wire can achieve smooth and accurate output of the actuator through graded driving. When the distance between the position of the end of the elongated PAM and the desired position exceeds a preset error threshold, the PAM driving mode is started; when the distance between the position of the end of the actuator and the desired position reaches within the preset error threshold, the air pressure in the elongated PAM is kept unchanged, and the SMA drive is started at the same time. By adjusting the current passing through the SMA, the error is further reduced, so that the end of the elongated PAM can run smoothly to the desired position.

[0030] Beneficial Effects

[0031] The present invention can realize a pneumatic artificial muscle driving mode and a pneumatic artificial muscle and shape memory alloy hybrid driving mode through a switching device. In this embodiment, the pneumatic artificial muscle driving mode can realize fast driving with large stroke and high load; the pneumatic artificial muscle and shape memory alloy hybrid driving mode can realize a two-stage driving mode, which is beneficial to improving driving stability and repeated positioning accuracy; in addition, the pneumatic artificial muscle and shape memory alloy hybrid driving mode can realize variable stiffness adjustment of the driver through the antagonistic effect of the output force of the pneumatic artificial muscle and the shape memory alloy, and realize the flexibility and adaptability of the driver. The present invention only relies on the hybrid drive of different intelligent materials to realize large stroke output, variable stiffness adjustment and high-precision positioning, without the need for a motor, which greatly improves the system's integration level and power density ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a hybrid actuator based on smart materials;

[0033] Figure 2 It is a schematic diagram of the structure of a pneumatic artificial muscle actuator;

[0034] Figure 3 A schematic diagram of the structure of an SMA drive module and a switching device provided in a specific embodiment of the present invention;

[0035] Figure 4 is a schematic diagram of the structure of the fixing device C;

[0036] Figure 5 is a schematic diagram of the structure of the fixing device A;

[0037] Figure 6 The working principle diagram of the hybrid drive.

[0038] Among them: 1-upper bracket, 2-lower bracket, 3-base, 4-extension PAM, 5-pneumatic proportional valve, 6-air compressor, 7-SMA wire, 8-rear fixed pulley, 9-fixed device A, 10-programmable power supply, 11-fixed device C, 12-guide rail slider, 13-pneumatic push rod, 14-flat nylon rope, 15-wire rope, 16-front fixed pulley, 17-fixed device B, 18-front spring, 19-rear spring, 20-two-position five-way solenoid valve, 21-upper end plug, 22-lower end plug, 23-inner rubber tube, 24-outer rubber tube, 25-woven mesh, 26-A group clamp, 27-B group clamp, 28-boss, 29-air hole, 30-through hole, 31-annular structure, 32-angle connector, 33-first baffle, 34-secondary baffle, 35-round hole, 36-hexagonal copper column, 37-rectangular through hole, 38-concave connector, 39-pneumatic push rod patch, 40-edge round hole, 41-aluminum profile. DETAILED DESCRIPTION

[0039] The invention is further described below in conjunction with the accompanying drawings of the present invention, but it should not be understood that the above subject scope of the present invention is limited to the following embodiments. Without departing from the above ideas of the present invention, various substitutions and changes are made according to common technical knowledge and customary means in the art, which should all be included in the protection scope of the present invention.

[0040] like Figure 1-6 As shown, a hybrid actuator based on smart materials includes a fixed bracket, a pneumatic artificial muscle driving module, a shape memory alloy driving module and a switching device; wherein PAM represents pneumatic artificial muscle, and SMA represents shape memory alloy;

[0041] The fixed support comprises an upper support 1, a lower support 2 and a base 3; the base 3 is in an I-shape, and the upper support 1 and the lower support 2 are constructed by combining the base 3 with an aluminum profile 41;

[0042] The fixing device A9 is provided with a primary baffle 33, a secondary baffle 34, and a hexagonal copper column 36. The primary baffle 33 is fixed to the upper bracket 1 through an angle connector 32. The secondary baffle 34 of the fixing device A9 is provided with three circular holes 35.

[0043] The left and right ends of the concave connector 38 are fixed to the lower bracket 2 through the corner connectors 32;

[0044] The upper bracket 1 is used to horizontally fix the SMA drive module and the switching device;

[0045] The lower bracket 2 is used to vertically fix the PAM drive module;

[0046] The PAM drive module includes an elongated PAM 4, a pneumatic proportional valve 5 and an air compressor 6; the air compressor 6 provides an air source to the pneumatic proportional valve 5 through an air pipe, and the pneumatic proportional valve 5 provides the required air pressure to the elongated PAM 4 through an air pipe;

[0047] The SMA drive module includes three identical SMA wires 7, a rear fixed pulley 8, a fixing device A9 and a programmable power supply 10;

[0048] The left ends of the three SMA wires 7 are fixed in parallel in the circular hole 35 of the secondary baffle 34 at the left end of the fixing device A 9, and the right ends of the three SMA wires 7 are fixed in parallel to the right end of the fixing device C11 by passing through the rear fixed pulley 8. The power supply 10 is connected to the SMA wire 7 through a wire to provide current for driving the SMA wire 7;

[0049] The switching device includes a guide rail slider 12, a pneumatic push rod 13, a flat nylon rope 14, a wire rope 15, a front fixed pulley 16, a fixing device B17, a front spring 18, a rear spring 19 and a two-position five-way solenoid valve 20;

[0050] The fixing device C11 is fixed to the guide rail slider 12 by bolts;

[0051] The pneumatic push rod 13 is fixed above the rectangular through hole 37 of the fixing device C11, and a pneumatic push rod patch 39 is pasted on the end of the pneumatic push rod 13;

[0052] The right end of the fixture C11 is provided with three edge circular holes 40 connected to the left end of the SMA wire 7, and the left and right side walls of the fixture C11 are respectively provided with rectangular through holes 37 through which the flat nylon rope 14 passes;

[0053] The guide rail slider 12 is fixed to the upper bracket 1 through the fixing device A9, the pneumatic push rod 13 is fixed above the guide rail slider 12 through the fixing device C11, the flat nylon rope 14 passes through the gap between the end of the pneumatic push rod 13 and the fixing device C11, the left end of the flat nylon rope 14 is connected to the upper end of the wire rope 15 through the front fixed pulley 16, and the lower end of the wire rope 15 is connected to the elongated PAM 4, the right end of the flat nylon rope 14 is connected to the left end of the rear end spring 19, the right end of the rear end spring 19 is fixed to the fixture B17, the left end and the right end of the front end spring 18 are respectively connected to the left end of the fixture A9 and the left end of the fixture C11, the two-position five-way solenoid valve 20 is connected to the pneumatic push rod 13 through the air pipe to provide an air source for the pneumatic push rod 13, the on and off of the two-position five-way solenoid valve 20 realizes the pushing out and retracting of the pneumatic push rod 13, and completes the compression and release of the flat nylon rope 14, thereby realizing the PAM driving mode and the mixed driving mode of PAM and SMA.

[0054] The elongated PAM 4 comprises an upper end plug 21, a lower end plug 22, an inner rubber tube 23, an outer rubber tube 24, a braided mesh 25, a group A clamp 26 and a group B clamp 27;

[0055] The centers of the upper end plug 21 and the lower end plug 22 have an integrated boss 28 structure;

[0056] The two ends of the inner rubber tube 23 are fixed between the two bosses 28 by a group A of clamps 26;

[0057] The upper end plug 21 has air holes 29 for air inlet and outlet and a through hole 30 for the wire rope to pass through, and the center of the boss 28 of the lower end plug 22 has an annular structure 31 for fixing the wire rope;

[0058] The outer rubber tube 24 is fixed between the upper plug 21 and the lower plug 22, and the braided net 25 is fixed between the upper plug 21 and the lower plug 22 through the B group clamp 27 and is placed on the outer layer of the outer rubber tube 24;

[0059] The upper end plug 21 is fixed on the female connecting piece 38 .

[0060] The provision of the inner rubber tube 23 ensures good air tightness of the elongated PAM4 and avoids air leakage caused by the embedding of the steel wire rope 15 .

[0061] The front spring 18 is fixed to the outside of the front fixed pulley 16 through a hexagonal copper column 36 to avoid interfering with the movement of the pulley.

[0062] The front end spring 18 is in a pre-tensioned state, and the rear end spring 19 is in a pre-tensioned state.

[0063] The female connector 38 is 3D printed.

[0064] A hybrid actuator based on smart materials, when the pneumatic push rod 13 is in the push-out state and the SMA wire 7 is energized, the air pressure in the elongated PAM4 remains unchanged, the contraction of the SMA wire 7 drives the fixing device C11 to move, thereby driving the movement of the nylon rope 14, and the nylon rope 14 transmits the force to the end of the elongated PAM4 through the steel wire 15, causing the end of the elongated PAM4 to move, at this time the hybrid actuator can realize the hybrid drive of the elongated PAM4 and the SMA wire 7, and the drive of the SMA wire 7 is more stable than that of the elongated PAM4. Due to the antagonistic effect of the output force of the elongated PAM4 and the SMA wire 7, the stiffness of the hybrid actuator can change with the change of the air pressure in the elongated PAM4 and the drive current of the SMA wire 7.

[0065] The hybrid driver based on the elongated PAM4 and SMA wire 7 is driven in stages to achieve smooth and accurate output of the driver. When the distance between the position of the end of the elongated PAM4 and the desired position exceeds a preset error threshold, the PAM driving mode is started; when the distance between the position of the end of the driver and the desired position reaches within the preset error threshold, the air pressure in the elongated PAM4 is kept unchanged, and the SMA7 drive is started at the same time. By adjusting the current passing through the SMA, the error is further reduced, so that the end of the elongated PAM4 can run smoothly to the desired position.

Claims

1. A hybrid drive based on smart materials, characterized in that: It includes a fixing bracket, a pneumatic artificial muscle driving module, a shape memory alloy driving module and a switching device; wherein PAM stands for pneumatic artificial muscle and SMA stands for shape memory alloy; The fixed support comprises an upper support (1), a lower support (2) and a base (3); the base (3) is in an I-shape, and the upper support (1) and the lower support (2) are constructed by combining an aluminum profile (41) with the base (3); The fixing device A (9) is provided with a primary baffle (33), a secondary baffle (34), and a hexagonal copper column (36); the primary baffle (33) is fixed to the upper bracket (1) through an angle connector (32); the secondary baffle (34) of the fixing device A (9) is provided with three circular holes (35); The left and right ends of the concave connecting piece (38) are fixed to the lower bracket (2) through the corner connecting pieces (32); The upper bracket (1) is used to horizontally fix the SMA drive module and the switching device; The lower bracket (2) is used to vertically fix the PAM drive module; The PAM drive module comprises an extension type PAM (4), a pneumatic proportional valve (5) and an air compressor (6); the air compressor (6) provides an air source for the pneumatic proportional valve (5) through an air pipe, and the pneumatic proportional valve (5) provides the extension type PAM (4) with the required air pressure through the air pipe; The SMA driving module comprises three identical SMA wires (7), a rear fixed pulley (8), a fixing device A (9) and a programmable power supply (10); The left ends of the three SMA wires (7) are fixed in parallel in the circular holes (35) of the secondary baffle (34) at the left end of the fixing device A (9); the right ends of the three SMA wires (7) are fixed in parallel to the right end of the fixing device C (11) by passing through the rear fixed pulley (8); the power source (10) is connected to the SMA wires (7) through wires to provide current for driving the SMA wires (7); The switching device comprises a guide rail slider (12), a pneumatic push rod (13), a flat nylon rope (14), a steel wire rope (15), a front fixed pulley (16), a fixing device B (17), a front spring (18), a rear spring (19) and a two-position five-way solenoid valve (20); The fixing device C (11) is fixed to the guide rail slider (12) by bolts; The pneumatic push rod (13) is fixed above the rectangular through hole (37) of the fixing device C (11), and a pneumatic push rod patch (39) is pasted on the end of the pneumatic push rod (13); The right end of the fixing device C (11) is provided with three edge circular holes (40) connected to the left end of the SMA wire (7), and the left and right side walls of the fixing device C (11) are respectively provided with rectangular through holes (37) through which the flat nylon rope (14) passes; The guide rail slider (12) is fixed to the upper bracket (1) through a fixing device A (9), the pneumatic push rod (13) is fixed above the guide rail slider (12) through a fixing device C (11), the flat nylon rope (14) passes through the gap between the end of the pneumatic push rod (13) and the fixing device C (11), the left end of the flat nylon rope (14) is connected to the upper end of the steel wire rope (15) through the front fixed pulley (16), the lower end of the steel wire rope (15) is connected to the lower end of the elongated PAM (4), and the right end of the flat nylon rope (14) is connected to the left end of the rear spring (19) The right end of the rear spring (19) is fixed to the fixture B (17), and the left and right ends of the front spring (18) are respectively connected to the left end of the fixture A (9) and the left end of the fixture C (11). The two-position five-way solenoid valve (20) is connected to the pneumatic push rod (13) through the air pipe to provide an air source for the pneumatic push rod (13). The on and off of the two-position five-way solenoid valve (20) realizes the pushing out and retracting of the pneumatic push rod (13), and completes the compression and release of the flat nylon rope (14), thereby realizing the PAM driving mode and the mixed driving mode of PAM and SMA.

2. A hybrid drive based on smart materials according to claim 1, characterized in that: The elongated PAM (4) comprises an upper end plug (21), a lower end plug (22), an inner rubber tube (23), an outer rubber tube (24), a braided mesh (25), a group A clamp (26) and a group B clamp (27); The centers of the upper end plug (21) and the lower end plug (22) have an integrated boss (28) structure; The two ends of the inner rubber tube (23) are fixed between the two bosses (28) through a group A clamp (26); The upper end plug (21) has air holes (29) for air inlet and outlet and a through hole (30) for the steel wire rope to pass through, and the center of the boss (28) of the lower end plug (22) has an annular structure (31) for fixing the steel wire rope; The outer rubber tube (24) is fixed between the upper plug (21) and the lower plug (22), and the braided net (25) is fixed between the upper plug (21) and the lower plug (22) through a group B clamp (27) and is placed on the outer layer of the outer rubber tube (24); The upper end plug (21) is fixed on the concave connecting piece (38); The provision of the inner rubber tube (23) ensures good air tightness of the elongated PAM4 and avoids air leakage caused by the embedding of the steel wire rope (15).

3. The hybrid drive based on smart materials according to claim 1, characterized in that: The front end spring (18) is fixed to the outside of the front end fixed pulley (16) through a hexagonal copper column (36) to avoid interfering with the movement of the pulley.

4. The hybrid drive based on smart materials according to claim 1, characterized in that: The front spring (18) is in a pre-tensioned state, and the rear spring (19) is in a pre-tensioned state, so as to provide a restoring force for the switching device.

5. The hybrid drive based on smart materials according to claim 1, characterized in that: The concave connecting piece (38) is 3D printed.

6. The hybrid drive based on smart materials according to claim 1, characterized in that: The braiding angle of the braided mesh (25) in an uninflated state is 66°; The outer rubber tube (24) expands radially under the action of air pressure, and the interaction between the outer rubber tube (24) and the braided mesh (25) causes a change in the braiding angle, resulting in an elongated movement trend. At the same time, the outer braided mesh (25) limits the radial expansion of the outer rubber tube (24).

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