A hybrid drive based on smart materials

Abstract

The application relates to a hybrid driver based on intelligent materials, which comprises a fixed support, a PAM driving module, an SMA driving module and a switching device; the fixed support is composed of two layers of supports, the upper layer is provided with the SMA driving module and the switching device, and the lower layer is provided with the PAM driving module; the PAM driving module comprises an elongated 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 and a steel wire rope and a power supply; the switching device comprises a guide rail sliding block mechanism, the fixing device B, the fixing device C, the front end spring, the rear end spring, the nylon rope, the steel wire, a pneumatic push rod, a two-position five-way electromagnetic valve and a connecting device; the switching device is connected with the PAM driving module and the SMA driving module; and the wide-range movement of the driver is realized through the PAM driving mode.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent material hybrid driver, and particularly relates to a hybrid driver based on intelligent material. BACKGROUND

[0002] With the rapid development of robot technology, especially the appearance of soft continuum robot, the driver is required to have good compliance, light weight and other characteristics, and is required to have high power density ratio, high integration, convenient motion control, variable stiffness and other advantages. Benefiting from the larger output displacement and output force of the pneumatic artificial muscle driver, it is being widely applied to the design of continuum robot arm. Although the continuum robot arm driven by the pneumatic artificial muscle shows excellent motion range and load capacity compared with other driving modes, due to the viscoelasticity of the material, obvious hysteresis nonlinearity and airflow flow and other factors, it is difficult for the pneumatic driven robot arm to ensure accurate positioning operation. The existing single flexible intelligent material driver is difficult to meet the above requirements at the same time, and many researchers and scholars pay attention to the hybrid driver. However, the existing hybrid driver is mostly concentrated in the motor driven rope or nylon wire and pneumatic artificial muscle hybrid driver, and has low integration level and low power density. Limited by the size of the motor, the number of wires that can be arranged in the robot arm is limited, and the output force that can be provided is insufficient. SUMMARY

[0003] The application provides a hybrid driver based on intelligent material, and the specific technical scheme is as follows:

[0004] A hybrid driver based on intelligent material, comprising a fixed support, a pneumatic artificial muscle driving module, a shape memory alloy driving module and a switching device; wherein PAM represents a pneumatic artificial muscle, and SMA represents a shape memory alloy;

[0005] The fixed support comprises an upper support, a lower support and a base; the base is in the shape of an I-shaped section, and the upper support and the lower support are combined and built with the base through aluminum profiles;

[0006] The fixing device A is provided with a first baffle, a second baffle and a hexagonal copper column, the first baffle is fixed to the upper support through an angle connecting piece, and the second baffle of the fixing device A is provided with three round holes;

[0007] The left and right ends of the concave connecting piece are fixed on the lower support through an angle connecting piece;

[0008] The upper support is used for horizontally fixing the SMA driving module and the switching device;

[0009] The lower support is used for vertically fixing the PAM driving module;

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

[0011] The SMA driving module comprises three identical SMA wires, a rear end fixed pulley, a fixing device A and a programmable power supply;

[0012] The left ends of the three SMA wires are fixed in the round holes of the second baffle of the fixing device A, and the right ends of the three SMA wires are fixed to the right end of the fixing device C through the rear end fixed pulley, and the power supply is connected with the SMA wires through wires to provide current for the driving of the SMA wires;

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

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

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

[0016] The right end of the fixing device C is provided with three edge round holes connected with the left ends of the SMA wires, 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 slides on the upper layer support through the fixing device A, the pneumatic push rod is fixed above the guide rail slider through the 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 with the upper end of the steel wire rope through the front end fixed pulley, the lower end of the steel wire rope is connected with the lower end of the elongated PAM, the right end of the flat nylon rope is connected with 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 with the left end of the fixing device A and the left end of the fixing device C, the two-position five-way electromagnetic valve is connected with the pneumatic push rod through an air pipe to provide air source for the pneumatic push rod, the on-off of the two-position five-way electromagnetic valve realizes the pushing out and retraction of the pneumatic push rod, the compression and release of the flat nylon rope are completed, and thus the PAM driving mode and the mixed driving mode of the PAM and the SMA are realized.

[0018] The preferred scheme of the mixed driver based on intelligent materials is that the elongated PAM comprises an upper end plug, a lower end plug, an inner layer rubber tube, an outer layer rubber tube, a woven 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 inner layer rubber tube is fixed between the two protrusions by the A group of clamps;

[0021] The upper end plug has a gas hole for the gas flow and a through hole for the steel wire rope, and the protrusion center of the lower end plug has a ring structure for fixing the steel wire rope;

[0022] The outer layer rubber tube is fixed between the upper end plug and the lower end plug, and the woven mesh is fixed between the upper end plug and the lower end plug by the B group of clamps and is placed outside the outer layer rubber tube.

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

[0024] The inner layer 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 scheme of the hybrid driver based on intelligent materials is that the front end spring is fixed outside the front end fixed pulley through a hexagonal copper column to avoid interfering with the movement of the pulley.

[0026] The preferred scheme of the hybrid driver based on intelligent materials is that the front end spring is in a pre-stretched state and the rear end spring is in a pre-stretched state.

[0027] The preferred scheme of the hybrid driver based on intelligent materials is that the concave connector is 3D printed.

[0028] The weaving angle of the woven mesh in the un-inflated state is 66°.

[0029] The outer layer rubber tube expands radially under the action of air pressure, and through the interaction of the outer layer rubber tube and the woven mesh, the change of the weaving angle is caused, and the stretching movement trend is generated, at the same time, the outer layer woven mesh limits the radial expansion of the outer layer rubber tube.

[0030] When the pneumatic push rod is in the push-out state and the SMA wire is powered on, the hybrid driver based on intelligent materials keeps the air pressure in the elongated PAM unchanged, the contraction of the SMA wire drives the fixed 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 movement of the end of the elongated PAM, at this time, the hybrid driver can realize the hybrid driving of the elongated PAM and the SMA wire, and the driving of the SMA wire is more stable than that of the elongated PAM. Due to the antagonistic effect of the output forces of the elongated PAM and the SMA wire, the stiffness of the hybrid driver can change with the change of the air pressure in the elongated PAM4 and the driving current of the SMA wire.

[0031] The smooth and accurate output of the driver can be realized by the step-by-step driving of the hybrid driver based on the elongated PAM and the SMA wire, when the distance between the position where the end of the elongated PAM is located and the expected position exceeds the preset error threshold, the PAM driving mode is started; when the distance between the position where the end of the driver is located and the expected position reaches the preset error threshold range, the air pressure in the elongated PAM is kept unchanged, and the SMA driving is started at the same time, the error is further reduced by adjusting the current passing through the SMA, so that the end of the elongated PAM is smoothly run to the expected position. Advantageous effects

[0032] The switching device can realize the driving mode of the pneumatic artificial muscle and the hybrid driving mode of the pneumatic artificial muscle and the shape memory alloy. In the embodiment, the driving mode of the pneumatic artificial muscle can realize fast driving with large stroke and high load; the hybrid driving mode of the pneumatic artificial muscle and the shape memory alloy can realize two-stage driving mode, which is beneficial to improve the driving stability and the repeat positioning accuracy; in addition, the hybrid driving mode of the pneumatic artificial muscle and the shape memory alloy can realize the stiffness adjustment of the driver through the antagonistic effect of the output forces of the pneumatic artificial muscle and the shape memory alloy, and realize the flexibility and adaptability of the driver. The present application only relies on the hybrid driving of different intelligent materials to realize large stroke output, stiffness adjustment and high-precision positioning, without the need of motor, which greatly improves the integration level and power density ratio of the system. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structure schematic view of a hybrid driver based on intelligent materials;

[0034] Figure 2 It is a structure schematic view of a pneumatic artificial muscle driver;

[0035] Figure 3 It is a structure schematic view of the SMA driving module and the switching device provided in the embodiment;

[0036] Figure 4 It is a structure schematic view of the fixing device C;

[0037] Figure 5 It is a structure schematic view of the fixing device A;

[0038] Figure 6 It is a working principle diagram of the hybrid driver.

[0039] Wherein: 1-Upper support, 2-Lower support, 3-Base, 4-Extended PAM, 5-Pneumatic proportional valve, 6-Air compressor, 7-SMA wire, 8-Rear fixed pulley, 9-Fixing device A, 10-Programmable power supply, 11-Fixing device C, 12-Guide rail slider, 13-Pneumatic push rod, 14-Flat nylon rope, 15-Steel wire rope, 16-Front fixed pulley, 17-Fixing 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-braided mesh, 26-A group clamp, 27-B group clamp, 28-bore, 29-air hole, 30-through hole, 31-ring structure, 32-corner connector, 33-first stage baffle, 34-second stage 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 Implementation

[0040] The invention will be further described below with reference to the accompanying drawings, but it should not be construed that the scope of the invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practice in the art without departing from the above-described spirit of the invention should be included within the scope of protection of the invention.

[0041] like Figures 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.

[0042] The fixed support includes an upper support 1, a lower support 2, and a base 3; the base 3 is I-shaped, and the upper support 1 and the lower support 2 are assembled with the base 3 by means of aluminum profile 41;

[0043] 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 support 1 by a corner connector 32. The secondary baffle 34 of the fixing device A9 is provided with three round holes 35.

[0044] The concave connector 38 is fixed to the lower bracket 2 at both ends by corner connectors 32;

[0045] The upper bracket 1 is used to horizontally fix the SMA drive module and the switching device;

[0046] The lower bracket 2 is used to vertically fix the PAM drive module;

[0047] The PAM driving module includes an elongated PAM 4, a pneumatic proportional valve 5 and an air compressor 6; the air compressor 6 provides air source for the pneumatic proportional valve 5 through an air pipe, and the pneumatic proportional valve 5 provides required air pressure for the elongated PAM 4 through an air pipe;

[0048] The SMA driving module includes three identical SMA wires 7, a rear end fixed pulley 8, a fixing device A 9 and a programmable power supply 10;

[0049] The left ends of the three SMA wires 7 are fixed in the round holes 35 of the two-stage baffle 34 at the left end of the fixing device A 9, and the right ends of the three SMA wires 7 are fixed at the right end of the fixing device C 11 by passing through the rear end fixed pulley 8, and the power supply 10 is connected with the SMA wires 7 through wires to provide current for the driving of the SMA wires 7;

[0050] The switching device includes a guide rail slider 12, a pneumatic push rod 13, a flat nylon rope 14, a steel wire rope 15, a front end fixed pulley 16, a fixing device B 17, a front end spring 18, a rear end spring 19 and a two-position five-way electromagnetic valve 20;

[0051] The fixing device C 11 is fixed with the guide rail slider 12 through bolts;

[0052] The pneumatic push rod 13 is fixed above the rectangular through hole 37 of the fixing device C 11, and the end of the pneumatic push rod 13 is pasted with a pneumatic push rod patch 39;

[0053] The right end of the fixing device C 11 is provided with three edge round holes 40 connected with the left ends of the SMA wires 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;

[0054] The guide rail slider 12 slides on the upper layer support 1 through the fixing device A 9, the pneumatic push rod 13 is fixed above the guide rail slider 12 through the 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 with the upper end of the steel wire rope 15 through the front end fixed pulley 16, the lower end of the steel wire rope 15 is connected with the lower end of the elongated PAM 4, the right end of the flat nylon rope 14 is connected with the left end of the rear end spring 19, the right end of the rear end spring 19 is fixed to the fixing device B 17, the left and right ends of the front end spring 18 are respectively connected with the left end of the fixing device A 9 and the left end of the fixing device C 11, the two-position five-way electromagnetic valve 20 is connected with the pneumatic push rod 13 through an air pipe to provide air source for the pneumatic push rod 13, the on-off of the two-position five-way electromagnetic valve 20 realizes the pushing out and retraction of the pneumatic push rod 13, and the compression and release of the flat nylon rope 14 are completed, so as to realize the PAM driving mode and the mixed driving mode of PAM and SMA.

[0055] The elongated PAM 4 comprises an upper end plug 21, a lower end plug 22, an inner layer rubber tube 23, an outer layer rubber tube 24, a woven mesh 25, a group A clamp 26 and a group B clamp 27;

[0056] The upper end plug 21 and the lower end plug 22 have an integrated boss 28 structure in the center;

[0057] The inner layer rubber tube 23 is fixed between the two bosses 28 by the group A clamp 26;

[0058] The upper end plug 21 has a gas hole 29 for air flow and a through hole 30 for the steel wire rope to pass through, and the boss 28 in the center of the lower end plug 22 has an annular structure 31 for fixing the steel wire rope;

[0059] The outer layer rubber tube 24 is fixed between the upper end plug 21 and the lower end plug 22, and the woven mesh 25 is fixed between the upper end plug 21 and the lower end plug 22 by the group B clamp 27 and is placed outside the outer layer rubber tube 24;

[0060] The upper end plug 21 is fixed on the concave connector 38.

[0061] The inner layer rubber tube 23 is provided to ensure good air tightness of the elongated PAM 4, and to avoid air leakage caused by the embedding of the steel wire rope 15.

[0062] The front end spring 18 is fixed outside the front end fixed pulley 16 by a hexagonal copper column 36 to avoid interference with the movement of the pulley.

[0063] The front end spring 18 is in a pre-stretched state, and the rear end spring 19 is in a pre-stretched state.

[0064] The concave connector 38 is 3D printed.

[0065] A hybrid driver based on smart materials, when the pneumatic push rod 13 is in the push-out state and the SMA wire 7 is powered on, the air pressure in the elongated PAM 4 remains unchanged, the contraction of the SMA wire 7 drives the movement of the fixing device C11, thereby driving the movement of the nylon rope 14, the nylon rope 14 transmits the force to the end of the elongated PAM 4 through the steel wire rope 15, causing the movement of the end of the elongated PAM 4, at this time the hybrid driver can realize the hybrid driving of the elongated PAM 4 and the SMA wire 7, and the driving of the SMA wire 7 is more stable than that of the elongated PAM 4. Due to the antagonistic effect of the output forces of the elongated PAM 4 and the SMA wire 7, the stiffness of the hybrid driver can be changed with the change of the air pressure in the elongated PAM 4 and the driving current of the SMA wire 7.

[0066] Based on the mixed driver of the elongated PAM4 and the SMA wire 7, the smooth and accurate output of the driver can be realized through the hierarchical driving. When the distance between the position of the elongated PAM4 end and the expected position exceeds the preset error threshold, the PAM driving mode is started. When the distance between the position of the driver end and the expected position reaches the preset error threshold range, the gas pressure in the elongated PAM4 is kept unchanged, and the SMA7 driving is started. Through the adjustment of the SMA current, the error is further reduced, so that the elongated PAM4 end runs smoothly to the expected position.

Claims

1. A hybrid actuator based on smart materials, characterized in that, It includes a fixed support, a pneumatic artificial muscle drive module, a shape memory alloy drive module, and a switching device; where PAM represents pneumatic artificial muscle and SMA represents shape memory alloy. The fixed support includes an upper support (1), a lower support (2) and a base (3); the base (3) is I-shaped, and the upper support (1) and the lower support (2) are assembled with the base (3) by means of aluminum profile (41); The fixing device A (9) is provided with a first-level baffle (33), a second-level baffle (34), and a hexagonal copper column (36). The first-level baffle (33) is fixed to the upper bracket (1) by a corner connector (32). The second-level baffle (34) of the fixing device A (9) is provided with three round holes (35). The concave connector (38) is fixed to the lower support (2) at both ends by corner connectors (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 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; The SMA drive module includes 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 round 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 C (11) after passing over the rear fixed pulley (8). The power supply (10) is connected to the SMA wires (7) through the wire to provide current for driving the SMA wires (7). The switching device includes 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 the end of the pneumatic push rod (13) is attached with a pneumatic push rod patch (39). The right end of the fixing device C (11) is provided with three edge round holes (40) for connecting 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 flat nylon rope (14) passes. The guide rail slider (12) slides on the upper support (1) via the fixing device A (9). The pneumatic push rod (13) is fixed above the guide rail slider (12) via the 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) via 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). 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 fixing device B (17). The left and right ends of the front spring (18) are respectively connected to the left end of the fixing device A (9) and the fixing device C. (11) The left end is connected to the two-position five-way solenoid valve (20) and the pneumatic push rod (13) through the air pipe to provide air source for the pneumatic push rod (13). The opening and closing of the two-position five-way solenoid valve (20) realizes the pushing and retraction of the pneumatic push rod (13), and completes the pressing and releasing of the flat nylon rope (14), thereby realizing the PAM drive mode and the mixed drive mode of PAM and SMA. The elongated PAM (4) includes 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 upper plug (21) and the lower plug (22) have an integrated boss (28) structure at their center; The inner rubber tube (23) is fixed at both ends to the middle of the two bosses (28) by the A group clamps (26); The upper end plug (21) has an air hole (29) for airflow and a through hole (30) for the wire rope to pass through, and the lower end plug (22) has a ring structure (31) at the center of the boss (28) for fixing the wire rope. The outer rubber tube (24) is fixed between the upper end plug (21) and the lower end plug (22), and the braided mesh (25) is fixed between the upper end plug (21) and the lower end plug (22) by the B group 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 connector (38); The inner rubber tube (23) ensures good airtightness of the elongated PAM4 and avoids air leakage caused by the embedding of the steel wire rope (15).

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

3. The hybrid actuator based on smart materials according to claim 1, characterized in that, The front spring (18) is in a pre-stretched state, and the rear spring (19) is in a pre-stretched state.

4. A hybrid actuator based on smart materials according to claim 1, characterized in that, The concave connector (38) is 3D printed.

5. A hybrid actuator based on smart materials according to claim 1, characterized in that, The braiding angle of the woven mesh (25) in the uninflated state is 66°; The outer rubber tube (24) expands radially under air pressure. Through the interaction between the outer rubber tube (24) and the braided mesh (25), the braiding angle changes, resulting in an elongation tendency. At the same time, the outer braided mesh (25) restricts the radial expansion of the outer rubber tube (24).

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