Foot-wheel matching type multi-degree-of-freedom piezoelectric robot with foot and leg integrated design and excitation method thereof

Abstract

The invention discloses a foot and leg integrated design foot and wheel matched type multi-degree-of-freedom piezoelectric robot and an excitation method thereof, and belongs to the field of centimeter-level small robots. According to the robot, piezoelectric ceramics are pasted on an integrated base body, and the piezoelectric ceramics are divided into two pieces of Y-direction piezoelectric ceramics and two pieces of Z-direction piezoelectric ceramics; when two paths of sine excitation signals with the phase difference of 90 degrees are applied to the Y-direction piezoelectric ceramic and the Z-direction piezoelectric ceramic respectively, the base body beam bends and vibrates in the horizontal (Y-direction) direction and the vertical (Z-direction) direction, the foot bottom end is driven to synthesize an elliptic track in the YOZ plane, and rotation motion is achieved through friction between the foot end and the ground. Similarly, an elliptical track can be synthesized in an XOZ plane under excitation of different signals, and linear motion is achieved through friction between the foot end and the ground; when a pulse signal is applied to the piezoelectric ceramic, the robot moves at a micron-order micro step pitch. The robot has the advantages of being simple in structure, high in response speed, capable of giving consideration to fast macro motion and precise micro motion and the like, and faces scenes such as large-range precise detection.

Description

Technical Field

[0001] The present invention belongs to the field of small robots, and particularly relates to a wheel-foot cooperative multi-degree-of-freedom piezoelectric robot with an integrated foot-leg design and its excitation method. Background Art

[0002] In recent years, due to their advantages such as small size, light weight, and flexible movement, small robots have become one of the important research directions in the field of robotics. Small robots can work in narrow spaces inaccessible to humans, and these advantages enable them to have a wide range of applications in fields such as search and rescue, detection, biomedicine, and micromanipulation.

[0003] Most traditional small robots adopt electromagnetic drive methods. This method requires transmission mechanisms, and the structure is relatively complex, which limits their further miniaturized design. In addition, electromagnetic drive robots also have problems such as electromagnetic interference, which all limit their application scope. In recent years, intelligent materials have developed rapidly. Among them, piezoelectric materials have the advantages of fast response speed, high resolution, power-off self-locking, and no electromagnetic interference, and are widely used in the field of small robots. Piezoelectric robots are relatively easy to achieve miniaturization, high resolution and other characteristics compared with traditional electromagnetic drive robots.

[0004] The wheel-foot cooperative multi-degree-of-freedom piezoelectric robot proposed by the present invention adopts an integrated foot-leg design and utilizes the compounding of different vibration modes of an integrated piezoelectric drive unit to achieve multi-degree-of-freedom movement. The overall structure of this small robot is simple and compact, with high stiffness. By different excitation methods to excite different vibration modes, linear and rotational movements are respectively achieved. Specifically, through the compounding of the Z-direction and Y-direction bending vibration modes, an elliptical trajectory is synthesized at the foot end to achieve steering movement. Through the compounding of the Z-direction bending vibration and the X-direction longitudinal vibration modes, an elliptical trajectory is synthesized at the foot end to achieve X-direction linear movement. All in all, the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot of the present invention is small in size and light in weight, and at the same time has the advantages of fast response, high resolution, multi-degree-of-freedom movement, etc. These characteristics make it have broad application prospects in fields such as precision operation, large-range positioning and handling, and detection. Summary of the Invention

[0005] In order to solve the problems of complex structure, low resolution, and electromagnetic interference of traditional electromagnetic drive robots, the present invention proposes a wheel-foot cooperative multi-degree-of-freedom piezoelectric robot with an integrated foot-leg design and its excitation method.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention proposes a wheel-foot cooperative multi-degree-of-freedom piezoelectric robot with an integrated foot-leg design, including a piezoelectric actuator unit, a driving foot, and a supporting wheel;

[0008] The piezoelectric actuating unit includes a square foot-leg integrated substrate, a first group of piezoelectric ceramics, and a second group of piezoelectric ceramics;

[0009] The first group of piezoelectric ceramics includes two Y-direction piezoelectric ceramics;

[0010] The second group of piezoelectric ceramics includes two Z-direction piezoelectric ceramics;

[0011] Piezoelectric ceramics are respectively pasted around the square foot-leg integrated substrate for exciting the required vibration modes;

[0012] By exciting piezoelectric ceramics in different directions, the piezoelectric actuating unit bends and vibrates in different directions, so as to realize multi-degree-of-freedom motion through the combination of different modes;

[0013] Under the excitation of corresponding signals, the end of the driving foot can generate an actuating trajectory and actuates through friction with the ground;

[0014] The supporting wheels are used for support and guidance so that the robot can realize multi-degree-of-freedom motion.

[0015] Furthermore, there is a certain angle between the axis of the above-mentioned integrated substrate and the ground.

[0016] Furthermore, the above-mentioned piezoelectric actuating unit has multiple vibration modes, including bending vibration along the vertical Z direction, bending vibration along the horizontal Y direction, and longitudinal vibration along the X direction.

[0017] Furthermore, the above-mentioned piezoelectric actuating unit further includes a thin-wall connecting beam and a counterweight;

[0018] The thin-wall connecting beam is used for vibration isolation;

[0019] The counterweight is used for weighting.

[0020] Furthermore, the multi-degree-of-freedom piezoelectric robot further includes a carrying platform;

[0021] The carrying platform is fixed on the integrated substrate and is used for carrying a power supply and carrying objects.

[0022] The present invention also provides an excitation method for a foot-wheel cooperative multi-degree-of-freedom piezoelectric robot applied to foot-leg integrated design. The excitation method can excite the driving foot of the robot to synthesize an elliptical trajectory in the YOZ plane and realize the turning motion around the supporting wheel through the friction between the foot end and the ground; and can excite the driving foot of the robot to synthesize an elliptical trajectory in the XOZ plane and realize the linear motion in the X direction through the friction between the foot end and the ground.

[0023] Furthermore, in the above-mentioned multi-degree-of-freedom motion, the excitation method for realizing the turning motion is as follows:

[0024] Step 1: Apply a sinusoidal excitation signal with a gradually increasing amplitude to the piezoelectric ceramic in the Y direction and a cosine excitation signal with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the Y direction to increase and the displacement in the Z direction to decrease;

[0025] Step 2: Apply a sinusoidal excitation signal with a gradually decreasing amplitude to the piezoelectric ceramic in the Y direction and a cosine excitation signal with a gradually increasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the Y direction to decrease and the displacement in the -Z direction to increase;

[0026] Step 3: Apply a sinusoidal excitation signal with a gradually increasing amplitude to the piezoelectric ceramic in the Y direction and a cosine excitation signal with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the -Y direction to increase and the displacement in the -Z direction to decrease;

[0027] Step 4: Apply a sinusoidal excitation signal with a gradually decreasing amplitude to the piezoelectric ceramic in the Y direction and a cosine excitation signal with a gradually increasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the -Y direction to decrease and the displacement in the Z direction to increase;

[0028] Step 5: Repeat Steps 1 to 4. The tip of the foot synthesizes an elliptical trajectory in the YOZ plane, and due to the friction with the ground, it receives a frictional force in the Y direction from the ground, thereby achieving a turning motion around the support wheel.

[0029] Furthermore, in the multi-degree-of-freedom motion, the excitation method for achieving linear motion is as follows:

[0030] Step 6: Apply two sinusoidal excitation signals with a gradually increasing amplitude and a 180° phase difference to the two piezoelectric ceramics in the Y direction, and a cosine excitation signal with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the X direction to increase and the displacement in the Z direction to decrease;

[0031] Step 7: Apply two sinusoidal excitation signals with a gradually decreasing amplitude and a 180° phase difference to the two piezoelectric ceramics in the Y direction, and a cosine excitation signal with a gradually increasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the X direction to decrease and the displacement in the -Z direction to increase;

[0032] Step 8: Apply two sinusoidal excitation signals with a gradually increasing amplitude and a 180° phase difference to the two piezoelectric ceramics in the Y direction, and a cosine excitation signal with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the -X direction to increase and the displacement in the -Z direction to decrease;

[0033] Step 9: Apply two sinusoidal excitation signals with a gradually decreasing amplitude and a 180° phase difference to the two piezoelectric ceramics in the Y direction, and a cosine excitation signal with a gradually increasing amplitude to the piezoelectric ceramic in the Z direction, causing the displacement of the driving foot in the -X direction to decrease and the displacement in the Z direction to increase;

[0034] Step 10: Repeat Steps 6 to 10. The tip of the foot synthesizes an elliptical trajectory in the XOZ plane, and due to the friction with the ground, it receives a frictional force in the X direction from the ground, thereby achieving a linear motion in the X direction.

[0035] Further, in the excitation method, the phase difference of the excitation signals applied to the piezoelectric ceramics in the Y direction and the Z direction can be changed, that is, from 90° to -90°, so as to change the direction of the frictional force received, and further enable the robot to move in the reverse direction.

[0036] Advantages of the present invention:

[0037] 1. The present invention provides a wheel-foot cooperation type multi-degree-of-freedom piezoelectric robot, which has a small volume and weight, simple and compact structure, high stiffness, and combines the characteristics of multi-degree-of-freedom and high resolution.

[0038] 2. The driving feet of the wheel-foot cooperation type multi-degree-of-freedom piezoelectric robot provided by the present invention can have various expansion forms. In addition to the wheel-type driving feet, they can also be expanded into semi-circular, cross-shaped, circular-ring-shaped, and spoke circular-ring-shaped. Different forms of driving feet have their own advantages. For example, the circular-ring-shaped can more easily excite traveling waves, obtain a more standard elliptical trajectory, and achieve a better driving effect; the spoke circular-ring-shaped driving feet have enhanced obstacle-crossing ability on the basis of the circular-ring-shaped.

[0039] 3. The wheel-foot cooperation type multi-degree-of-freedom piezoelectric robot provided by the present invention excites different vibration modes of the base through different excitation methods to respectively achieve linear and rotational motions. Specifically, two excitation signals with a phase difference of 90° excite the piezoelectric ceramics in the Z direction and the Y direction, so that the Z-direction and Y-direction bending vibration modes are combined, and an elliptical trajectory is synthesized at the foot end to achieve a steering motion; two excitation signals with a phase difference of 180° respectively excite two piezoelectric ceramics in the Y direction, and a third signal with a phase difference of 90° from it excites the piezoelectric ceramic in the Z direction, so that the Z-direction bending vibration and the X-direction longitudinal vibration modes are combined, and an elliptical trajectory is synthesized at the foot end to achieve a linear motion in the X direction.

[0040] The robot described in the present invention has flexible movement and has broad application prospects in the fields of precision operation, large-range positioning and handling, detection, etc. Description of the Drawings

[0041] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required to be used in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 is the three-dimensional structure diagram of the wheel-foot cooperation type multi-degree-of-freedom piezoelectric robot proposed by the present invention;

[0043] Figure 2 is the three-dimensional structure diagram of the piezoelectric actuation unit proposed by the present invention;

[0044] Figure 3 It is the three-dimensional structure diagram of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot proposed by the present invention, which adopts a square foot-leg integrated matrix;

[0045] Figure 4 It is the top view of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot proposed by the present invention;

[0046] Figure 5 It is the structure diagram and excitation signal (U is the excitation voltage, t is the time) of the rotational motion of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot described in the present invention. Among them, Figure (a) is the deformation schematic diagram and excitation signal of the robot foot end at t = T / 4, Figure (b) is the deformation schematic diagram and excitation signal of the robot foot end at t = T / 2, Figure (c) is the deformation schematic diagram and excitation signal of the robot foot end at t = 3T / 4, and Figure (d) is the deformation schematic diagram and excitation signal of the robot foot end at t = T;

[0047] Figure 6 It is the structure diagram and excitation signal (U is the excitation voltage, t is the time) of the linear motion of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot described in the present invention. Among them, Figure (a) is the deformation schematic diagram and excitation signal of the robot foot end at t = T / 4, Figure (b) is the deformation schematic diagram and excitation signal of the robot foot end at t = T / 2, Figure (c) is the deformation schematic diagram and excitation signal of the robot foot end at t = 3T / 4, and Figure (d) is the deformation schematic diagram and excitation signal of the robot foot end at t = T;

[0048] Figure 7 It is the stepping motion excitation method and its motion form diagram of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot described in the present invention. Among them, Figure (a) is the excitation signals with different frequencies and duty cycles, and Figure (b) is that the robot can obtain different step pitches;

[0049] Figure 8 It is the different expansion forms of the driving feet of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot described in the present invention. Among them, Figure (a) is a semi-circular driving foot, Figure (b) is a cross-shaped driving foot, Figure (c) is a circular-ring driving foot, and Figure (d) is a spoke circular-ring driving foot.

[0050] Among them, 1- represents the piezoelectric actuator unit, 1-1 represents the square foot-leg integrated matrix, 1-2 represents the first group of piezoelectric ceramics, 1-3 represents the second group of piezoelectric ceramics, 1-2-1 represents the first piece of Y-direction piezoelectric ceramics, 1-2-2 represents the second piece of Y-direction piezoelectric ceramics, 1-3-1 represents the first piece of Z-direction piezoelectric ceramics, 1-3-2 represents the second piece of Z-direction piezoelectric ceramics, 1-4 represents the thin-walled connecting beam, 1-4-1 represents the first thin-walled connecting beam, 1-4-2 represents the second thin-walled connecting beam, 1-5 represents the counterweight block, 1-6 represents the rigid connecting block, 1-6-1 represents the first rigid connecting block, 1-6-2 represents the second rigid connecting block, 2 represents the driving foot, 3 represents the support wheel, and 4 represents the bearing platform. DETAILED DESCRIPTION

[0051] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Specific implementation method one:

[0053] Combination Figures 1 to 4 This embodiment describes a multi-degree-of-freedom piezoelectric robot with integrated foot and leg design and wheel combination. The robot structure is as follows: Figure 1 As shown, it includes a piezoelectric actuator unit 1, a driving foot 2, two supporting wheels 3 and a carrying platform 4. The structure of the piezoelectric actuator unit 1 is as follows Figure 2As shown in the figure, it mainly includes a square foot-leg integrated base 1-1, a first group of piezoelectric ceramics 1-2, a second group of piezoelectric ceramics 1-3, a thin-wall connecting beam 1-4, a counterweight 1-5, and a rigid connecting block 1-6. Piezoelectric ceramics are pasted on the square integrated base 1-1. The piezoelectric ceramics are divided into 2 Y-direction piezoelectric ceramics and 2 Z-direction piezoelectric ceramics. Piezoelectric ceramics are pasted on the four sides of the square foot-leg integrated base 1-1 respectively to excite the required vibration modes. When two Z-direction piezoelectric ceramics are excited, the actuating unit vibrates vertically (Z-direction) in a bending manner. When two Y-direction piezoelectric ceramics are excited, the actuating unit vibrates horizontally (Y-direction) in a bending manner. Multi-degree-of-freedom motion is achieved through the compounding of different modes. The first rigid connecting block 1-6-1 is connected to the counterweight 1-5 through the first thin-wall connecting beam 1-4-1, and the second rigid connecting block 1-6-2 is connected to the counterweight 1-5 through the second thin-wall connecting beam 1-4-2. The thin-wall connecting beam 1-4 is used for vibration isolation, the counterweight 1-5 is used for configuration, and the rigid connecting block 1-6 is used for fixing the carrying platform and the passive wheel. Under the excitation of corresponding signals, the end of the driving foot 2 can generate an actuating trajectory and actuates through friction with the ground. The supporting wheel 3 is used for support and guidance so that the robot can achieve multi-degree-of-freedom motion. The carrying platform 4 is fixed on the integrated base and is used for carrying the power supply and handling objects.

[0054] The wheel-foot cooperative multi-degree-of-freedom piezoelectric robot adopts a square foot-leg integrated base 1-1, with a compact structure. There is a certain angle between the axis 1-1 of the integrated base and the ground, as Figure 3 shown. Figure 4 This is the top view of the robot.

[0055] The square foot-leg integrated base 1-1 has multiple vibration modes, such as vertical (Z-direction) bending vibration, horizontal (Y-direction) bending vibration, and longitudinal vibration in the X-direction. By compounding the Z-direction and Y-direction bending vibrations, steering motion is achieved. By compounding the Z-direction bending vibration and the X-direction longitudinal vibration, X-direction linear motion is achieved. Specific Embodiment 2:

[0057] Combined with Figures 5 to 7 to illustrate this embodiment, an excitation method for a wheel-foot cooperative multi-degree-of-freedom piezoelectric robot applied to the integrated design of feet and legs. The excitation method can excite the driving feet of the robot to synthesize an elliptical trajectory in the YOZ plane, and realize the steering motion around the supporting wheel through the friction between the foot end and the ground, as Figure 5 shown; it can excite the driving feet of the robot to synthesize an elliptical trajectory in the XOZ plane, and realize the linear motion in the X-direction through the friction between the foot end and the ground, as Figure 6 shown.

[0058] In the multi-degree-of-freedom motion, the excitation method for realizing the steering motion is as follows:

[0059] Step 1: As shown in Figure 5 (a), apply a sinusoidal excitation signal A with a gradually increasing amplitude to the piezoelectric ceramic in the Y direction, and apply a cosine excitation signal B with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, so that the displacement of the driving foot in the Y direction becomes larger and the displacement in the Z direction becomes smaller;

[0060] Step 2: As shown in Figure 5 (b), apply a sinusoidal excitation signal A with a gradually decreasing amplitude to the piezoelectric ceramic in the Y direction, and apply a cosine excitation signal B with a gradually increasing amplitude to the piezoelectric ceramic in the Z direction, so that the displacement of the driving foot in the Y direction becomes smaller and the displacement in the -Z direction becomes larger;

[0061] Step 3: As shown in Figure 5 (c), apply a sinusoidal excitation signal A with a gradually increasing amplitude to the piezoelectric ceramic in the Y direction, and apply a cosine excitation signal B with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, so that the displacement of the driving foot in the -Y direction becomes larger and the displacement in the -Z direction becomes smaller;

[0062] Step 4: As shown in Figure 5 (d), apply a sinusoidal excitation signal A with a gradually decreasing amplitude to the piezoelectric ceramic in the Y direction, and apply a cosine excitation signal B with a gradually increasing amplitude to the piezoelectric ceramic in the Z direction, so that the displacement of the driving foot in the -Y direction becomes smaller and the displacement in the Z direction becomes larger;

[0063] Step 5: Repeat Steps 1 to 4. The end of the foot synthesizes an elliptical trajectory in the YOZ plane, and is subjected to a frictional force in the Y direction from the ground due to the friction with the ground, thereby realizing the turning motion around the support wheel.

[0064] In the multi-degree-of-freedom motion, the excitation method for realizing linear motion is as follows:

[0065] Step 6: As shown in Figure 6 (a), apply two sinusoidal excitation signals A and B with a gradually increasing amplitude and a phase difference of 180° to two piezoelectric ceramics in the Y direction respectively, and apply a cosine excitation signal C with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, so that the displacement of the driving foot in the X direction becomes larger and the displacement in the Z direction becomes smaller;

[0066] Step 7: As shown in Figure 6 (b), apply two sinusoidal excitation signals A and B with a gradually decreasing amplitude and a phase difference of 180° to two piezoelectric ceramics in the Y direction respectively, and apply a cosine excitation signal C with a gradually increasing amplitude to the piezoelectric ceramic in the Z direction, so that the displacement of the driving foot in the X direction becomes smaller and the displacement in the -Z direction becomes larger;

[0067] Step 8: As shown in Figure 6 (c), apply two sinusoidal excitation signals A and B with a gradually increasing amplitude and a phase difference of 180° to two piezoelectric ceramics in the Y direction respectively, and apply a cosine excitation signal C with a gradually decreasing amplitude to the piezoelectric ceramic in the Z direction, so that the displacement of the driving foot in the -X direction becomes larger and the displacement in the -Z direction becomes smaller;

[0068] Step 9: As shown inFigure 6 As shown in (d), two piezoelectric ceramics in the Y direction are respectively applied with two sinusoidal excitation signals A and B with a phase difference of 180° and gradually decreasing amplitudes, and a piezoelectric ceramic in the Z direction is applied with a gradually increasing cosine excitation signal C, so that the displacement of the driving foot in the -X direction becomes smaller and the displacement in the Z direction becomes larger;

[0069] Step ten: Repeat steps six to ten. The foot end synthesizes an elliptical trajectory in the XOZ plane, and is subjected to a frictional force in the X direction from the ground due to friction with the ground, thereby realizing linear motion in the X direction.

[0070] For the described excitation method, by changing the phase difference of the excitation signals applied to the piezoelectric ceramics in the Y direction and the Z direction, that is, changing from 90° to -90°, the direction of the frictional force received can be changed, and thus the robot can realize reverse motion.

[0071] See Figure 7 , the described wheel-foot cooperative robot can perform stepping motion with a micron-level step pitch under the excitation of a sine pulse signal. By setting excitation signals with different frequencies and duty cycles, the robot can obtain different step pitches.

[0072] When the described robot is excited by a sine pulse signal, the motion situation in each period is similar to that during the above linear motion. Therefore, overall, the robot performs stepping motion. The larger the duty cycle of the excitation signal, the larger the step pitch of the robot.

[0073] See Figure 7 , the robot is Figure 7 under the action of the excitation signal with a 20% duty cycle shown in (a) and performs micron-level stepping motion. Its displacement changes in a stepped manner with time, and the distance between every two steps is the step pitch of the robot's one-time motion. As Figure 7 shown in (b), the larger the duty cycle, the larger the step pitch.

[0074] The piezoelectric robot described in the present invention can move with a sub-micron-level step pitch, and this feature makes it have a wide range of application prospects in the fields of precision operation and detection, etc. Specific Embodiment Three:

[0076] Combined with Figure 8 to illustrate this embodiment, the driving feet of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot of the present invention can have different expansion forms. In addition to the type of driving foot introduced in Embodiment One, they can also be expanded into semi-circular, cross-shaped, circular ring-shaped, and spoke circular ring-shaped driving feet respectively, as shown in Figure 8 (a), 8(b), 8(c), 8(d) respectively.

[0077] Figure 8The different forms of driving feet each have their own advantages. The circular ring type can more easily excite traveling waves, obtain a more standard elliptical trajectory, and achieve better driving; the spoke circular ring type driving feet have increased obstacle-crossing ability on the basis of the circular ring type.

[0078] The other compositions, connection relationships, and excitation methods are the same as those in the first and second specific embodiments.

[0079] The above Figure 5 Shows the principle and excitation method of the rotary motion of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot (U is the excitation voltage, t is the time). The figure shows the deformation schematic diagrams of the robot's foot end at four different moments (t = T / 4, t = T / 2, 3T / 4, t = T) within an excitation period (T). The star represents the initial position, and the circle represents the position after deformation. Finally, the foot end synthesizes an elliptical actuation trajectory in the YOZ plane, and rapid movement is achieved by accumulating multiple periods. Figure 6 Shows the principle and excitation method of the linear motion of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot (U is the excitation voltage, t is the time). The figure shows the deformation schematic diagrams of the robot's foot end at four different moments within an excitation period (T). Finally, the foot end synthesizes an elliptical actuation trajectory in the XOZ plane, and rapid movement is achieved by accumulating multiple periods. Figure 7 Shows the excitation method and motion form diagram of the stepping motion of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot. The robot moves in micrometer steps under the excitation of a sinusoidal pulse signal. This feature makes it have a wide range of application prospects in fields such as precision operation and detection.

[0080] The above has introduced in detail a wheel-foot cooperative multi-degree-of-freedom piezoelectric robot with an integrated foot and leg design and its excitation method proposed by the present invention, and has elaborated on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A foot-wheel combined multi-degree-of-freedom piezoelectric robot with an integrated foot and leg design, characterized in that, It includes a piezoelectric actuation unit (1), driving feet (2) and supporting wheels (3); The piezoelectric actuation unit (1) includes a square foot-leg integrated substrate (1-1), a first group of piezoelectric ceramics (1-2), and a second group of piezoelectric ceramics (1-3); The first group of piezoelectric ceramics (1-2) includes two Y-direction piezoelectric ceramics; The second group of piezoelectric ceramics (1-3) includes two Z-direction piezoelectric ceramics; Piezoelectric ceramics are respectively pasted around the square foot-leg integrated substrate for exciting the required vibration modes; By exciting the piezoelectric ceramics in different directions, the piezoelectric actuation unit (1) bends and vibrates in different directions, so as to realize multi-degree-of-freedom motion through the compounding of different modes; Under the excitation of corresponding signals, the end of the driving foot (2) can generate an actuation trajectory and actuate through friction with the ground; The supporting wheel (3) is used for supporting and guiding so that the robot can realize multi-degree-of-freedom motion.

2. The multi-degree-of-freedom piezoelectric robot with integrated foot and leg design according to claim 1 is characterized in that: There is a certain angle between the axis of the integrated substrate and the ground.

3. The foot-wheel combined multi-degree-of-freedom piezoelectric robot with an integrated foot and leg design according to claim 1, characterized in that, The piezoelectric actuation unit (1) has multiple vibration modes, including bending vibration along the vertical Z direction, bending vibration along the horizontal Y direction, and longitudinal vibration along the X direction.

4. The wheel-foot integrated and wheel-foot cooperating multi-degree-of-freedom piezoelectric robot according to claim 1, wherein, The piezoelectric actuation unit (1) further includes a thin-wall connecting beam (1-4), a counterweight (1-5), and a rigid connecting block (1-6); The thin-wall connecting beam (1-4) is used for vibration isolation; The counterweight (1-5) is used for counterweight; The rigid connecting block (1-6) is used for fixing the carrying platform and the passive wheel.

5. The multi-degree-of-freedom piezoelectric robot with integrated foot and leg design according to claim 1, characterized in that: It further includes a carrying platform (4); The carrying platform (4) is fixed on the integrated substrate and is used for carrying a power supply and carrying objects.

6. An excitation method for a foot-wheel cooperative multi-degree-of-freedom piezoelectric robot with an integrated foot and leg design as described in any one of claims 1-5, characterized in that, The excitation method can excite the driving feet of the robot to synthesize an elliptical trajectory in the YOZ plane, and realize the turning motion around the supporting wheel through the friction between the foot end and the ground; the excitation method can also excite the driving feet of the robot to synthesize an elliptical trajectory in the XOZ plane, and realize the linear motion in the X direction through the friction between the foot end and the ground.

7. The excitation method of the wheel-foot cooperation type multi-degree-of-freedom piezoelectric robot according to claim 6, characterized in that, In the multi-degree-of-freedom motion, the excitation method for realizing the turning motion is as follows: Step 1: Apply a sinusoidal excitation signal with a gradually increasing amplitude to the Y-direction piezoelectric ceramics, and apply a cosine excitation signal with a gradually decreasing amplitude to the Z-direction piezoelectric ceramics. The displacement of the driving foot along the Y direction becomes larger, and the displacement along the Z direction becomes smaller; Step 2: Apply a sinusoidal excitation signal with a gradually decreasing amplitude to the Y-direction piezoelectric ceramics, and apply a cosine excitation signal with a gradually increasing amplitude to the Z-direction piezoelectric ceramics. The displacement of the driving foot along the Y direction becomes smaller, and the displacement along the -Z direction becomes larger; Step 3: Apply a sinusoidal excitation signal with a gradually increasing amplitude to the Y-direction piezoelectric ceramics, and apply a cosine excitation signal with a gradually decreasing amplitude to the Z-direction piezoelectric ceramics. The displacement of the driving foot along the -Y direction becomes larger, and the displacement along the -Z direction becomes smaller; Step 4: Apply a sinusoidal excitation signal with a gradually decreasing amplitude to the Y-direction piezoelectric ceramics, and apply a cosine excitation signal with a gradually increasing amplitude to the Z-direction piezoelectric ceramics. The displacement of the driving foot along the -Y direction becomes smaller, and the displacement along the Z direction becomes larger; Step 5: Repeat Steps 1 to 4. The foot end synthesizes an elliptical trajectory in the YOZ plane, and is subjected to the frictional force in the Y direction of the ground through friction with the ground, thereby realizing the turning motion around the supporting wheel.

8. The excitation method of the wheel-foot cooperative multi-degree-of-freedom piezoelectric robot according to claim 6, characterized in that, In the multi-degree-of-freedom motion, the excitation method for realizing the linear motion is as follows: Step 6: Apply two sinusoidal excitation signals with a phase difference of 180° and gradually increasing amplitudes to the two piezoelectric ceramics in the Y direction, and apply a gradually decreasing cosine excitation signal to the piezoelectric ceramic in the Z direction, driving the foot to have a larger displacement in the X direction and a smaller displacement in the Z direction; Step 7: Apply two sinusoidal excitation signals with a phase difference of 180° and gradually decreasing amplitudes to the two piezoelectric ceramics in the Y direction, and apply a gradually increasing cosine excitation signal to the piezoelectric ceramic in the Z direction, driving the foot to have a smaller displacement in the X direction and a larger displacement in the -Z direction; Step 8: Apply two sinusoidal excitation signals with a phase difference of 180° and gradually increasing amplitudes to the two piezoelectric ceramics in the Y direction, and apply a gradually decreasing cosine excitation signal to the piezoelectric ceramic in the Z direction, driving the foot to have a larger displacement in the -X direction and a smaller displacement in the -Z direction; Step 9: Apply two sinusoidal excitation signals with a phase difference of 180° and gradually decreasing amplitudes to the two piezoelectric ceramics in the Y direction, and apply a gradually increasing cosine excitation signal to the piezoelectric ceramic in the Z direction, driving the foot to have a smaller displacement in the -X direction and a larger displacement in the Z direction; Step 10: Repeat Steps 6 to 10. The foot end synthesizes an elliptical trajectory in the XOZ plane, and is subject to the frictional force in the X direction from the ground due to the friction with the ground, thereby realizing linear motion in the X direction.

9. The excitation method of the wheel-foot cooperation type multi-degree-of-freedom piezoelectric robot according to claim 7 or 8, characterized in that, For the described excitation method, by changing the phase difference of the excitation signals applied to the piezoelectric ceramics in the Y and Z directions, the direction of the frictional force received can be changed, and thus the robot can achieve reverse motion.

10. The excitation method of the wheel-foot cooperation type multi-degree-of-freedom piezoelectric robot according to claim 9, characterized in that, Change the phase difference from 90° to -90°.

Images