Bionic manipulator, driving device and driving unit

Abstract

The invention provides a bionic manipulator, a driving device and a driving unit, the driving unit comprises an upper base, a lower base, a cylindrical spiral part, a shape memory alloy spring and an elastic reset part, the cylindrical spiral part is integrally formed into a cylindrical spiral structure by a dielectric elastomer, and electrode layers are arranged on the inner surface and the outer surface of the cylindrical spiral part and connected with a power supply; two ends of the shape memory alloy spring are fixedly connected with the upper base and the lower base, and the shape memory alloy spring is connected with a power supply and contracts after being electrified; the two ends of the reset elastic piece are connected with the upper base and the lower base. Two ends of the cylindrical spiral part are fixed, and the cylindrical spiral part is axially compressed to enable the reset elastic part to store energy and the shape memory alloy spring to contract when electrified; and the reset elastic piece releases potential energy during power failure, so that the two resets synchronously. The driving device adopts the driving unit, the bionic manipulator controls the finger action through the driving unit, the axial deformation quantity can be amplified, the driving stroke is improved, and the stroke limitation of a traditional structure is overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of bionic manipulators, and specifically relates to a bionic manipulator, a driving device, and a driving unit. Background Art

[0002] With the rapid development of fields such as flexible robots, medical assistance devices, and precision control equipment, the performance requirements for drivers are increasing day by day. These traditional rigid drivers, including motor drive, pneumatic drive, and hydraulic drive, each have some deficiencies. In motor drive, the power-to-mass ratio of the motor is low. To meet the conventional grasping requirements, a micro motor often needs to be combined with a speed reducer to increase the joint output torque, thereby increasing the assembly difficulty and the volume of the manipulator, and the cost is high. Pneumatic drive has more components and a cumbersome control system. Especially in the field of mobile robots, the gas source problem has not been well solved, and the equipment cost is high, the occupied space is large, the interference noise is large, and the speed stability is poor, which is not conducive to achieving accurate position and speed regulation. Hydraulic drive requires a hydraulic system, and the layout of the infusion pipeline is relatively complex, with a large volume and very high requirements for sealing.

[0003] In recent years, new intelligent material drive technologies represented by dielectric elastomers (DE) and shape memory alloys (SMA) have become research hotspots, but still face the following technical bottlenecks: The existing drivers have insufficient axial stroke due to the Poisson effect limitation of dielectric elastomers, and the electrode area is uneven, resulting in small displacements. Shape memory alloys rely on thermally induced phase changes to cause response hysteresis. The typical stroke of traditional linear SMA is only 5%. The cooperative efficiency between composite drive materials is low, and independent drive units are required for multi-degree-of-freedom systems, resulting in a large volume and complex control, which severely restricts the application efficiency and miniaturization development of flexible robots in scenarios such as precision operation and medical intervention. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems by providing a bionic manipulator, a driving device, and a driving unit to solve the problem of driving a flexible manipulator.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is: A driving unit, comprising:

[0006] An upper base and a lower base; a cylindrical helical member, which is a cylindrical helical structure integrally formed by a dielectric elastomer, and an inner electrode layer and an outer electrode layer are respectively provided on its inner surface and outer surface. The inner electrode layer is connected to the positive pole of the power supply through a first wire, and the outer electrode layer is connected to the negative pole of the power supply through a second wire;

[0007] A shape memory alloy spring is coaxially disposed in the inner cavity of the cylindrical spiral member, with two ends of the shape memory alloy spring being respectively fixed to the upper base and the lower base and connected to the power source via a third wire, wherein the shape memory alloy spring is configured to generate axial contraction when powered on and heated;

[0008] A reset elastic member is coaxially sleeved in the inner cavity of the cylindrical spiral member, and its two ends are respectively connected to the upper base and the lower base; wherein, the two ends of the cylindrical spiral member are respectively fixed to the upper base and the lower base, and when powered on, the cylindrical spiral member is subjected to the action of the electric field to produce axial compression deformation and drive the reset elastic member to store energy, while the shape memory alloy spring contracts; when powered off, the reset elastic member releases elastic potential energy, and links the cylindrical spiral member and the shape memory alloy spring to reset synchronously.

[0009] In some possible embodiments, the resetting elastic member is configured as a metal coil spring.

[0010] In some possible embodiments, the shape memory alloy spring and the metal coil spring are both cylindrical coil structures, and the inner diameter of the shape memory alloy spring is larger than that of the metal coil spring.

[0011] In some possible embodiments, a guide shaft is provided on the lower base, and a guide hole is correspondingly provided on the upper base. The guide shaft is slidably provided in the guide hole, and the cylindrical spiral element, shape memory alloy spring and reset elastic element are sleeved on the guide shaft.

[0012] The present invention provides a driving device, comprising a seat body and five of the above-mentioned driving units installed side by side on the seat body.

[0013] The present invention provides a bionic manipulator, comprising a palm and five flexible fingers connected to the palm, each of the flexible fingers is provided with a pull wire, one end of the pull wire is fixed to the fingertip of the flexible finger, and the other end is connected to the corresponding driving unit of a driving device.

[0014] In some possible embodiments, the flexible finger includes a flexible skeleton and a flexible finger sleeve covered on the flexible skeleton, a cavity is provided at each joint position of the flexible skeleton, a through hole connected to the cavity is opened on the palm surface of each joint position of the flexible skeleton, and a wire groove connected from the fingertip to the base of the finger is provided in the flexible skeleton.

[0015] In some possible embodiments, four mounting grooves are provided at the four finger positions of the palm, and the corresponding four flexible finger bottoms are fixed in the mounting grooves by fasteners. The thumb portion of the flexible finger can be rotatably connected to the thumb position of the palm, and a guide groove for guiding the pull wire is provided in the palm.

[0016] Advantages of the present invention: By adopting a nested combination of three "springs", namely a dielectric elastomer cylindrical spiral member, a shape memory alloy spring, and a reset elastic member, the structure of the drive unit is made more compact with a smaller space occupation ratio. At the same time, the synergistic effect between the springs improves the response frequency of the actuator, enabling it to respond more quickly to external control signals and achieve efficient motion conversion. The shape memory alloy itself has a strong driving force and can generate a significant shape recovery force during temperature change to achieve large deformation. The dielectric elastomer can also generate large stress and strain under the action of an electric field. After the two are combined, the drive unit can comprehensively utilize these two driving forces. Compared with a single memory alloy actuator or a dielectric elastomer drive unit, the output force is significantly enhanced, and it can better meet the requirements for a large driving force in operations such as grasping and holding of a bionic hand. The elastic potential energy is released through a carbon steel spring to link the cylindrical spiral member and the shape memory alloy spring to reset synchronously, with a fast response speed.

[0017] By combining the drive units into a drive device for driving the actions of each finger and connecting the drive device to the bionic manipulator, each finger can move flexibly and has a large grasping force. Brief Description of the Drawings

[0018] Figure 1 It is the front view of the drive unit provided by an embodiment of the present invention.

[0019] Figure 2 It is Figure 1 the sectional view taken along A-A in

[0020] Figure 3 It is the three-dimensional structural diagram of the dielectric elastomer connected to the power supply provided by an embodiment of the present invention.

[0021] Figure 4 It is the three-dimensional structural diagram of the bionic manipulator provided by an embodiment of the present invention.

[0022] Figure 5 It is the structural diagram of the four fingers of the bionic manipulator provided by an embodiment of the present invention.

[0023] Figure 6 It is Figure 5 the sectional view taken along B-B in

[0024] Figure 7 It is the three-dimensional structural diagram of the thumb provided by an embodiment of the present invention.

[0025] Figure 8 It is the schematic diagram of the drive unit of the present invention driving the finger to bend.

[0026] In the figure: 100, driving device; 110, driving unit; 111, upper base; 112, lower base; 113, dielectric elastomer cylindrical helix; 114, shape memory alloy spring; 115, reset elastic member; 116, power supply; 120, seat body; 200, bionic manipulator; 210, four-finger part; 211, flexible finger sleeve; 212, flexible skeleton; 213, cavity; 214, through hole; 215, wire groove; 220, thumb part; 221, bushing; 230, palm part; 240, cable. Detailed implementation manner

[0027] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings. The description in this part is only exemplary and explanatory, and should not have any restrictive effect on the protection scope of the present invention.

[0028] As Figure 1-3 shown, this embodiment provides a driving unit 110 based on dielectric elastomer, including an upper base 111 and a lower base 112. A cylindrical helix 113, a shape memory alloy spring 114 and a reset elastic member 115 are installed in the space between the upper base 111 and the lower base 112.

[0029] Among them, the cylindrical helix 113 is integrally formed by dielectric elastomer to form a cylindrical helix structure. Dielectric elastomer (DE) is a type of intelligent material with electro-induced deformation characteristics and belongs to the category of electroactive polymer (EAP). Its core characteristic is that it undergoes reversible deformation under the action of an electric field, and at the same time has high elasticity, low modulus and high dielectric performance. When the external excitation is removed, the EAP returns to its original state. In this embodiment, the strip-shaped dielectric elastomer is wound into a columnar helix structure. An electrode layer, that is, an inner electrode layer and an outer electrode layer, is respectively coated on the inner helical surface and the outer helical surface of the helical structure.

[0030] Referring to Figure 3 , in some embodiments, the inner electrode layer on the inner helical surface is electrically connected to the positive output terminal of the power supply 116 through a first wire, and the outer electrode layer on the outer helical surface is electrically connected to the negative output terminal of the power supply 116 through a second wire; electrode materials are coated on the two helical surfaces of the cylindrical helix 113 to form a flexible electrode. The electrodes are wound along the helical structure to form a continuous conduction path. By applying a voltage difference between the electrodes, the electrostatic interaction between their free charges generates axial contraction. Both ends of the dielectric elastomer cylindrical helix 113 are respectively fixed on the upper base 111 and the lower base 112.

[0031] Referring to Figure 1 and Figure 2In some possible implementations, the shape memory alloy spring 114 is coaxially disposed in the inner cavity of the cylindrical spiral member 113, with its two ends respectively fixed to the upper base 111 and the lower base 112, and connected to the power supply 116 through a third wire. The shape memory alloy spring 114 is configured to produce axial contraction when powered on and heated, and reset when cooled.

[0032] Continue to participate Figure 1 and Figure 2 In some possible implementations, the resetting elastic member 115 is coaxially sleeved in the inner cavity of the shape memory alloy spring 114 , and two ends of the resetting elastic member 115 are respectively connected to the upper base 111 and the lower base 112 .

[0033] When this embodiment is in use, when the power supply 116 is powered on, the cylindrical spiral member 113 is subjected to the action of the electric field to produce axial compression deformation, and at the same time the shape memory alloy spring 114 contracts, thereby jointly driving the reset elastic member 115 to store energy. When the power is off, the reset elastic member 115 releases elastic potential energy to drive, and the cylindrical spiral member 113 and the shape memory alloy spring 114 are synchronously reset.

[0034] That is, when the power source 116 is powered on, the compression force of the cylindrical spiral element 113 and the compression force of the shape memory alloy spring 114 are superimposed, increasing the pulling force of the drive unit 110. When the power source 116 is powered off, the cylindrical spiral element 113 automatically restores the extended state due to the characteristics of the dielectric elastomer, and the reset elastic element 115 actively pushes the shape memory alloy spring 114 to reset.

[0035] In some other possible embodiments, the resetting elastic member 115 is a metal coil spring, which is designed to be cylindrical and coaxially arranged in the middle of the shape memory alloy spring 114, and the inner diameter of the shape memory alloy spring 114 is larger than that of the metal coil spring. The metal coil spring is used to reset and extend the dielectric elastomer cylindrical coil member 113 and the shape memory alloy spring 114.

[0036] By nesting and combining three "cylindrical spring structures" (the dielectric elastomer cylindrical helical part 113, the shape memory alloy spring 114, and the reset elastic part 115), the response frequency and stability of the driving unit 110 are improved, and the space occupation ratio of the driving unit 110 is reduced. The shape memory alloy spring 114 itself has a certain driving force and can generate a shape recovery force under the condition of temperature change during power on and off, realizing a large deformation. The dielectric elastomer can also generate large stress and strain under the action of an electric field, converting electrical energy into mechanical energy and a part of heat energy, and the generated heat energy can also be used to heat and shrink the shape memory alloy spring 114. After the two are combined, the driving unit 110 can comprehensively utilize these two driving forces. Compared with a single memory alloy driver or dielectric elastomer driver, the output force is enhanced, and it can better cope with scenarios that require a large driving force.

[0037] The shape recovery process of the shape memory alloy spring 114 usually requires a certain amount of time to cool down, resulting in a relatively slow response speed. In this embodiment, the reset elastic part 115 is adopted to actively reset the shape memory alloy spring 114, accelerating its reset reaction time.

[0038] Participate Figure 1 And Figure 2 In some embodiments, a guide shaft is provided on the lower base 112, a corresponding guide hole is provided on the upper base 111, the guide shaft is slidably arranged in the guide hole, and the dielectric elastomer cylindrical helical part 113 and the reset elastic part 115 are sleeved on the guide shaft. Optionally, there are three annular grooves on the opposite surfaces of the upper base 111 and the lower base 112 for placing the helical dielectric elastomer cylindrical helical part 113, the shape memory alloy spring 114, and the metal helical spring (reset elastic part 115) to hold them and prevent them from moving left and right.

[0039] Refer to Figure 4 Referring to this, an embodiment of the present invention further provides a driving device 100, including a seat body 120 and five driving units 110 of the above embodiments arranged side by side on the seat body 120.

[0040] Specifically, five mounting holes are provided on the seat body 120, and the five driving units 110 are respectively fixedly installed in the corresponding mounting holes. The cylindrical helical parts 113 of the five driving units 110 share a power supply. Each driving unit 110 is respectively connected to a control module, and the compression amount of the driving unit 110 is controlled by controlling each control module.

[0041] Continue to refer to Figure 4, embodiments of the present invention also provide a bionic manipulator 200, including a palm part 230 and five flexible fingers connected to the palm part 230. The five flexible fingers are respectively a thumb part 220 and a four-finger part 210. The four-finger part 210 includes an index finger, a middle finger, a ring finger, and a little finger. A wire 240 is arranged in each flexible finger. One end of the wire 240 is fixed inside the fingertip of the flexible finger, and the other end is connected to the corresponding drive unit 110 of the drive device 100 in the above embodiments. The bending of the corresponding finger is controlled by the contraction of each drive unit 110.

[0042] Reference Figure 4 , Figure 5 and Figure 6 , in some embodiments, the flexible fingers (the four-finger part 210 and the thumb part 220) include a flexible skeleton 212 and a flexible finger sleeve 211 coated on the skeleton. Optionally, the flexible finger and the flexible finger sleeve 211 are made of silica gel material and have the ability to return to their original state after bending. Cavities 213 are arranged at each joint of the flexible skeleton 212 to reduce the stiffness here and make it easy to bend here. Through holes 214 communicating with the cavities 213 are opened in a small area directly above each joint, so that the material of the flexible skeleton 212 joints will not expand too much to both sides when bending, and the size of the through holes 214 is not designed too large so that the skeleton here can also support the flexible finger sleeve 211 well when the finger bends, and the flexible finger sleeve 211 will not collapse. A wire groove 215 communicating from the fingertip to the finger root is arranged in the flexible skeleton 212. The wire 240 penetrates into the back of the skeleton fingertip, and the wire 240 is guided by the wire groove 215, so that the wire 240 remains in a plane when passing through the flexible skeleton 212, preventing the rope from swinging randomly left and right.

[0043] Reference Figure 4 and Figure 7 , in some embodiments, the thumb part 220 is rotatably connected to the thumb connection position of the palm part 230. The thumb part 220 is fixed on the rotating shaft arranged on the palm part 230 through a bushing 221. The rotating shaft can be controlled by a motor to rotate, realizing the overall rotation of the thumb part 220. Cooperating with its bending action, it can perform a grasping action with the remaining four-finger part 210.

[0044] Reference Figure 4 , in some examples, four installation grooves are arranged at the four-finger position of the palm part 230, and the bottoms of the four flexible fingers of the corresponding four-finger part 210 are fixed in the installation grooves through fasteners such as bolts.

[0045] Continue to refer to Figure 4, in some possible implementation manners, the wire ropes 240 led out from each flexible finger (the four-finger part 210 and the thumb part 220) are guided through the guiding grooves arranged in the palm part 230 to be led out from the bottom of the palm part 230 and connected to the driving device 100 arranged in the arm, and the actions of each finger are controlled through the driving device 100.

[0046] Reference Figure 8 , when the bionic manipulator 200 of this embodiment is specifically used, by controlling the energization and contraction of the corresponding driving unit 110, the wire rope 240 in the flexible finger is tightened, and the fingertip is pulled to bend towards the palm direction, so as to realize single-finger or coordinated multi-finger grasping. After power-off, the reset elastic member 115 pushes each driving unit 110 to reset, the wire rope 240 is relaxed, and each flexible finger relies on its own elasticity to restore to the straight state.

[0047] Thumb rotation adjustment: The motor driving the base of the thumb part 220 rotates the rotating shaft, driving the thumb part 220 to rotate around the axis (such as internal rotation and opposition or abduction), and cooperating with the flexible fingers of the four-finger part 210 to complete actions such as pinching and holding.

[0048] Independently regulate the compression amount of each driving unit 110 to realize the difference in the bending angles of different fingers. The control module can also be programmed to preset action sequences (such as making a fist, opening, pinching) to realize automatic operation.

[0049] It should be noted that in this article, the terms "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to this process, method, article or device.

[0050] In this article, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above examples is only used to help understand the method of the present invention and its core idea. The above is only the preferred implementation manner of the present invention. It should be pointed out that due to the limitation of literal expression, and objectively there are infinite specific structures. For those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements, refinements or changes can also be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, shall all be regarded as the protection scope of the present invention.

Claims

1. A drive unit, characterized in that: include: An upper base and a lower base; a cylindrical spiral member, which is a cylindrical spiral structure integrally formed by a dielectric elastomer, and an inner electrode layer and an outer electrode layer are respectively provided on the inner surface and the outer surface of the cylindrical spiral member, wherein the inner electrode layer is connected to the positive electrode of the power supply through a first wire, and the outer electrode layer is connected to the negative electrode of the power supply through a second wire; A shape memory alloy spring is coaxially disposed in the inner cavity of the cylindrical spiral member, with two ends of the shape memory alloy spring being respectively fixed to the upper base and the lower base and connected to the power source via a third wire, wherein the shape memory alloy spring is configured to generate axial contraction when powered on and heated; The reset elastic member is coaxially sleeved in the inner cavity of the cylindrical spiral member, and its two ends are respectively connected to the upper base and the lower base; wherein, the two ends of the cylindrical spiral member are respectively fixed on the upper base and the lower base, and when the power is on, the cylindrical spiral member is subjected to the action of the electric field to produce axial compression deformation and drive the reset elastic member to store energy, and at the same time the shape memory alloy spring contracts; when the power is off, the reset elastic member releases elastic potential energy, and links the cylindrical spiral member and the shape memory alloy spring to reset synchronously.

2. The drive unit according to claim 1, characterized in that: The resetting elastic member is configured as a metal coil spring.

3. The drive unit according to claim 2, characterized in that: The shape memory alloy spring and the metal coil spring are both cylindrical coil structures, and the inner diameter of the shape memory alloy spring is larger than that of the metal coil spring.

4. The drive unit according to any one of claims 1 to 3, characterized in that: The lower base is provided with a guide shaft, and the upper base is correspondingly provided with a guide hole. The guide shaft is slidably arranged in the guide hole, and the cylindrical spiral element, the shape memory alloy spring and the reset elastic element are sleeved on the guide shaft.

5. A driving device, characterized in that: The invention comprises a seat body and five drive units according to any one of claims 1 to 4 installed side by side on the seat body.

6. A bionic manipulator, characterized in that: It comprises a palm and five flexible fingers connected to the palm, each of the flexible fingers is provided with a pull wire, one end of the pull wire is fixed to the fingertip of the flexible finger, and the other end is connected to the corresponding driving unit of the driving device in claim 5.

7. The bionic manipulator according to claim 6, characterized in that: The flexible finger includes a flexible skeleton and a flexible finger sleeve wrapped on the flexible skeleton. A cavity is arranged at each joint position of the flexible skeleton. A through hole connected to the cavity is opened on the palm surface of each joint position of the flexible skeleton. A wire groove connected from the fingertip to the base of the finger is arranged in the flexible skeleton.

8. The bionic manipulator according to claim 7, characterized in that: Four mounting grooves are arranged at the four finger positions of the palm, and the corresponding four flexible finger bottoms are fixed in the mounting grooves by fasteners. The thumb portion of the flexible finger can be rotatably connected to the thumb position of the palm, and a guide groove for guiding the pull wire is arranged in the palm.

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