Novel piezoelectric three-legged jumping type robot and control method thereof

Abstract

The invention relates to the technical field of micro-robots, in particular to a novel piezoelectric three-legged jumping type robot and a control method thereof.The method includes the steps that a base of the robot is machined on beryllium copper through a laser cutting method, and then a piezoelectric ceramic piece is pasted on the base of the robot through epoxy resin glue; and finally, the piezoelectric driving legs are bent to obtain the appearance of the robot. And then a driving circuit and a lithium battery are connected, so that the motion mode of the robot can be controlled. Specifically, by changing a piezoelectric ceramic piece at the top of a body and applying voltages in different directions to piezoelectric driving legs, the piezoelectric driving legs continuously generate contraction and extension deformation, movement of the piezoelectric robot is achieved, and by applying voltages to different legs, displacement in a specific direction can be achieved. The piezoelectric ceramic piece on the top of the body can play a role in amplifying displacement of a single leg, and the robot can jump by applying voltage to the three legs and the ceramic piece on the top at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of micro-robots, and in particular to a novel piezoelectric three-legged jumping robot and a control method thereof. Background Art

[0002] In recent years, with the development of new materials and new technologies in my country, micro robots have become an important research direction due to their small size, light weight and ability to work in specific occasions. Piezoelectric robots have the advantages of high-frequency vibration, fast response speed and no electromagnetic interference and are widely used in bioengineering and military fields.

[0003] The traditional driving methods of micro robots include: electromagnetic driving method, motor driving method, hydraulic driving method, pneumatic driving method, and piezoelectric driving method. Among them, the piezoelectric driving method has unique advantages in micro robots due to its high driving efficiency, no electromagnetic interference, and simple structure. Piezoelectric robots are easy to achieve miniaturization, lightweight, high resolution and other characteristics.

[0004] The vibration of the piezoelectric vibrator elastic body is only at the micron level, and its vibration is difficult to be seen by the naked eye. The main body of the piezoelectric robot is piezoelectric ceramics. How to drive the robot through the vibration of ceramics is currently a more difficult problem. Summary of the invention

[0005] The purpose of the present invention is to provide a novel piezoelectric three-legged jumping robot and a control method thereof, aiming to convert piezoelectric ceramic micro-displacement drive into movement visible to the naked eye, and realize free movement in six directions and upward jumping movement.

[0006] To achieve the above-mentioned object, the present invention provides a novel piezoelectric three-legged jumping robot, comprising a body and three piezoelectric driving legs, wherein the base shape of the body and the piezoelectric driving legs is obtained by using laser cutting on beryllium copper, and then the piezoelectric ceramic sheet is pasted on the base using epoxy resin glue, and the piezoelectric driving legs are bent into shape after uniform pressing;

[0007] The main body is circular, and the three piezoelectric driving legs are evenly distributed on the circumference. The angles between the piezoelectric driving legs are all 120° and are centrally symmetrical. The angle between the piezoelectric driving legs and the horizontal part of the main body is 135°.

[0008] Among them, the main body has a circular piezoelectric ceramic piece only on the top, and the piezoelectric driving legs have piezoelectric ceramic pieces on the top and bottom. The piezoelectric ceramic pieces on the main body and the piezoelectric driving legs are made of PZT-5H.

[0009] Among them, the new type of piezoelectric three-legged jumping robot also includes a driving circuit and a lithium battery. The driving circuit is a soft board circuit. The driving circuit and the lithium battery can both be arranged above the circular piezoelectric ceramic sheet of the body.

[0010] The driving circuit is designed based on the ICL8038 signal generator and is used to generate three waveforms: triangle wave, sine wave and square wave.

[0011] The present invention also proposes a novel piezoelectric three-legged jumping robot control method, which is used to control the novel piezoelectric three-legged jumping robot, and divides the control period into four time periods t1 to t4, comprising the following steps:

[0012] Step 1: When t=0~t1, a positive voltage is applied to the circular piezoelectric ceramic piece on the top of the body and the top and bottom of the piezoelectric driving leg respectively, the base of the robot is grounded, the polarization direction of the circular piezoelectric ceramic piece is the same as the direction of the applied voltage, the polarization direction of the top ceramic piece of the piezoelectric driving leg is opposite to the direction of the applied voltage, and the polarization direction of the bottom ceramic piece of the piezoelectric driving leg is the same as the direction of the applied voltage;

[0013] Step 2: When t=t1-t2, the voltage applied to the circular piezoelectric ceramic and the piezoelectric driving leg is gradually reduced;

[0014] Step 3: When t=t2-t3, the voltage applied to the circular piezoelectric ceramic piece and the piezoelectric driving leg gradually increases, the polarization direction of the circular piezoelectric ceramic piece is the same as the direction of the applied voltage, the polarization direction of the top ceramic piece of the piezoelectric driving leg is opposite to the direction of the applied voltage, and the polarization direction of the bottom ceramic piece of the piezoelectric driving leg is the same as the direction of the applied voltage;

[0015] Step 4: When t=t3-t4, the voltage applied to the circular piezoelectric ceramic piece and the piezoelectric driving leg is gradually reduced.

[0016] The present invention provides a novel piezoelectric three-legged jumping robot and its control method, which is processed by laser cutting on beryllium copper to form the robot base, and then epoxy resin glue is used to stick piezoelectric ceramic sheets on the robot base, and finally the piezoelectric driving legs are bent to obtain the robot's appearance; then the driving circuit and lithium battery are connected to control the robot's movement. Specifically, by changing the piezoelectric ceramic sheet on the top of the body and applying voltages in different directions to the piezoelectric driving legs, the piezoelectric driving legs are continuously contracted and elongated to achieve the movement of the piezoelectric robot, and by applying voltages to different legs, displacement in a specific direction can be achieved. The piezoelectric ceramic sheet on the top of the body can amplify the displacement of a single leg, and by applying voltages to the three legs and the top ceramic sheet at the same time, the robot can be made to jump. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of a main body and piezoelectric driving legs of a novel piezoelectric three-legged jumping robot of the present invention.

[0019] Figure 2 It is a schematic diagram of the basic wiring mode of the driving circuit of the present invention through internal supply bias voltage regulation.

[0020] Figure 3 The invention discloses a wiring diagram for adjusting the distortion, duty cycle and frequency of the driving circuit diagram of the invention when adjusting the output sine wave distortion.

[0021] Figure 4 The present invention is a wiring diagram for adjusting the distortion and duty cycle of the drive circuit diagram of the present invention after an external 100K potentiometer is connected when adjusting the output sine wave distortion.

[0022] Figure 5 It is a detailed structural diagram of the driving circuit of the present invention.

[0023] Figure 6 It is a schematic diagram of the polarization direction and the direction of applied voltage of the novel piezoelectric three-legged jumping robot of the present invention.

[0024] Figure 7 It is a motion state schematic diagram of corresponding process steps of a novel piezoelectric three-legged jumping robot control method of the present invention.

[0025] Figure 8 This is a schematic diagram of the electric field and polarization direction of the piezoelectric ceramic in the d31 working mode.

[0026] Fig. 9 It is a schematic structural diagram of a piezoelectric three-legged jumping robot in a specific embodiment of the present invention.

[0027] Fig.10 It is a comparison of deformation data of the piezoelectric driving leg with and without the addition of the ceramic sheet in a specific embodiment of the present invention.

[0028] Fig.11 It is a schematic diagram of the result of simulating square wave output by the driving circuit of a specific embodiment of the present invention in Protues.

[0029] Fig.12It is a schematic diagram of the result of simulating triangular wave output by the driving circuit of a specific embodiment of the present invention in Protues.

[0030] Fig.13 It is a schematic diagram of the result of simulating sinusoidal wave output by the driving circuit of a specific embodiment of the present invention in Protues. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0032] See also Figure 1 The present invention provides a novel piezoelectric tripod jumping robot, comprising a body and three piezoelectric driving legs, wherein the base shapes of the body and the piezoelectric driving legs are obtained by laser cutting on beryllium bronze, and then the piezoelectric ceramic sheet PZT-5H is pasted on the base by epoxy resin glue, and the piezoelectric driving legs are bent into shape after uniform pressing;

[0033] The main body is circular, and the three piezoelectric driving legs are evenly distributed on the circumference. The angles between the piezoelectric driving legs are all 120° and are centrally symmetrical. The angle between the piezoelectric driving legs and the horizontal part of the main body is 135°.

[0034] Specifically, the piezoelectric driving legs are made by using epoxy resin glue to stick the piezoelectric ceramic sheet PZT-5H on the substrate. The pressing method is to apply 10g uniform pressure to the piezoelectric driving legs, so that they are evenly pressed for 24 hours. After being pressed, they are made into piezoelectric driving legs, and then the piezoelectric driving legs are bent into the shape of a three-legged robot.

[0035] The piezoelectric ceramic piece PZT-5H is only attached to the top of the body, and the piezoelectric ceramic pieces PZT-5H are attached to the top and bottom of the piezoelectric driving leg.

[0036] The novel piezoelectric tripod jumping robot also includes a driving circuit and a lithium battery. The driving circuit is a soft board circuit. Both the driving circuit and the lithium battery can be arranged above the piezoelectric ceramic sheet PZT-5H of the body.

[0037] The driving circuit is designed based on the ICL8038 signal generator and is used to generate three waveforms: triangle wave, sine wave and square wave.

[0038] Specifically, the driving circuit is composed of modules such as power supply circuit, frequency adjustment, peak and trough distortion adjustment, duty cycle adjustment, frequency range switching, voltage following, etc. The circuit is small and light, and can be mounted on the upper end of a piezoelectric resonant robot. Due to the small and light characteristics of the robot, it does not affect the movement of the robot, and allows the robot to achieve the effect of an onboard power supply and be separated from the signal generator.

[0039] Since the ICL8038 single-chip function generator has two working modes, that is, the frequency adjustment voltage of the output function signal can be supplied internally or externally. In the initial stage, the present invention uses the following wiring diagrams adjusted by the internal bias voltage to test the chip and observe its characteristics: Figure 2 (a) is the basic connection method. Figure 2 (b) and Figure 2 (c) Adjustable duty cycle.

[0040] In the above application, since the frequency adjustment voltage bias of pin 7 is constant, the frequency and duty cycle of the function signal are determined by R A , R B and C, its frequency is f, period is T, t1 is the charging time of the oscillating capacitor, and t2 is the discharging time.

[0041] T=t1+t2,f=1 / T

[0042] Since the capacitor voltage rises to 1 / 3 of the specified input voltage of the comparator when the trigonometric function signal is charging, the time divided is

[0043]

[0044] When the capacitor is discharged and the voltage drops to 1 / 3 of the comparator input voltage, the time is

[0045]

[0046] right Figure 2 In (a), if R A =R B , we can get a square wave signal with a duty cycle of 50%. Its frequency f = 3 / (10R AC). In view of the shortcoming that the distortion of the above circuit cannot be adjusted, the improved scheme of the present invention realizes the adjustable positive and negative distortion of the sine wave. Since the sine wave generated by the chip is obtained by transforming the triangle wave through a nonlinear network. The 1st and 12th pins of the chip are set to adjust the distortion of the output sine wave. The figure below is a typical application for adjusting the distortion of the output sine wave, in which the 1st pin adjusts the nonlinear approach point during the charging time of the oscillating capacitor, and the 12th pin adjusts the nonlinear approach point during the discharge time of the oscillating capacitor. During the installation and debugging, two 100K multi-turn precision potentiometers are selected and repeatedly adjusted to achieve good square wave duty cycle adjustment and symmetrical adjustment of sine waves and triangle waves.

[0047] Figure 3 The circuit cannot adjust the frequency, and the frequency is adjustable by using an external frequency adjustment voltage. Through the 10k potentiometer, the adjustment range of the 8-terminal voltage can be controlled from 2 / 3Vcc to Vcc, such as Figure 4 shown.

[0048] The detailed structure of the entire drive circuit is as follows: Figure 5 shown.

[0049] Furthermore, the present invention also proposes a novel piezoelectric tripod jumping robot control method, which is used to control the novel piezoelectric tripod jumping robot, taking two cycles of a triangular wave as an example, dividing the control cycle into four time periods t1 to t4, and comprising the following steps:

[0050] Step 1: When t=0~t1, a positive voltage is applied to the circular piezoelectric ceramic piece on the top of the body and the top and bottom of the piezoelectric driving leg respectively, the base of the robot is grounded, the polarization direction of the circular piezoelectric ceramic piece is the same as the direction of the applied voltage, the polarization direction of the top ceramic piece of the piezoelectric driving leg is opposite to the direction of the applied voltage, and the polarization direction of the bottom ceramic piece of the piezoelectric driving leg is the same as the direction of the applied voltage;

[0051] Step 2: When t=t1-t2, the voltage applied to the circular piezoelectric ceramic and the piezoelectric driving leg is gradually reduced;

[0052] Step 3: When t=t2-t3, the voltage applied to the circular piezoelectric ceramic piece and the piezoelectric driving leg gradually increases, the polarization direction of the circular piezoelectric ceramic piece is the same as the direction of the applied voltage, the polarization direction of the top ceramic piece of the piezoelectric driving leg is opposite to the direction of the applied voltage, and the polarization direction of the bottom ceramic piece of the driving leg is the same as the direction of the applied voltage;

[0053] Step 4: When t=t3-t4, the voltage applied to the circular piezoelectric ceramic piece and the piezoelectric driving leg is gradually reduced.

[0054] For details, please refer to Figure 6 and Figure 7 , the material polarization direction and steps of the piezoelectric robot correspond to four different motion states as shown in the figure:

[0055] Figure 6 In the figure, the positive and negative electrodes represent the positive and negative electrodes of the piezoelectric material after polarization, the arrow inside the piezoelectric material represents the polarization direction of the piezoelectric material, and the black arrow outside the piezoelectric material represents the direction of the applied voltage.

[0056] like Figure 7 As shown: State 1: When t=0~t1, a positive voltage is applied to the circular piezoelectric ceramic piece at the top and the driving leg respectively. The polarization direction of the piezoelectric ceramic at the top of the circular piezoelectric ceramic piece is the same as the direction of the applied voltage. It works in the d31 mode and produces a downward contraction deformation. The polarization direction of the piezoelectric ceramic at the top of the piezoelectric driving leg is opposite to the direction of the applied voltage, and it produces an elongation deformation. The polarization direction of the piezoelectric ceramic at the bottom of the piezoelectric driving leg is the same as the direction of the applied voltage, and it produces a shortening deformation. When the circular piezoelectric ceramic piece at the top produces a downward contraction deformation, the piezoelectric driving leg produces an inward bending deformation at this time. The circular piezoelectric ceramic piece at the top can amplify the bending effect of the piezoelectric driving leg. At this time, the driving leg of the piezoelectric robot drags the robot forward by X1.

[0057] D31 working mode is as follows Figure 8 As shown, when the polarization direction of the piezoelectric ceramic and the direction of the applied electric field are both in the Z-axis direction, the piezoelectric ceramic will deform along the Y-axis. When the electric field direction of the Z-axis is the same as the polarization direction, the piezoelectric ceramic piece will shorten and deform along the Y-axis. When the electric field direction of the Z-axis is opposite to the polarization direction, the piezoelectric ceramic piece will lengthen and deform along the Y-axis.

[0058] State 2: When t=t1~t2, the voltage applied to the piezoelectric driving legs and the top circular piezoelectric ceramic piece gradually decreases, and the piezoelectric material is transformed from bending deformation to the initial state of the piezoelectric robot.

[0059] State 3: When t=t2~t3, the voltage applied to the piezoelectric driving leg gradually increases, and the voltage direction is positive. The polarization direction of the top circular piezoelectric ceramic piece is the same as the direction of the applied voltage. It works in the d31 mode and produces a downward contraction deformation. Similarly, the polarization direction of the piezoelectric ceramic at the top of the piezoelectric driving leg is opposite to the direction of the applied voltage, and it produces an elongation deformation. The polarization direction of the piezoelectric ceramic at the bottom of the piezoelectric driving leg is the same as the direction of the applied voltage, and it produces a shortening deformation. At this time, the piezoelectric driving leg produces an inward bending deformation. The top circular piezoelectric ceramic piece can amplify the bending effect of the piezoelectric driving leg. At this time, the piezoelectric driving leg of the piezoelectric robot drags the robot forward a distance of X2.

[0060] State 4: When t=t3-t4, the voltage applied to the piezoelectric driving leg and the circular piezoelectric ceramic piece on the top gradually decreases, and the deformation of the piezoelectric driving leg and the circular piezoelectric ceramic piece gradually returns to the initial state.

[0061] According to the working principle described above, the movement of the piezoelectric robot is realized by continuously contracting and extending the piezoelectric driven legs. Displacement in a specific direction can be achieved by applying voltage to different legs. The circular piezoelectric ceramic piece on the top of the body can amplify the displacement of a single leg. By applying voltage to the three legs and the top ceramic piece at the same time, the robot can make a jumping motion.

[0062] In order to further illustrate the feasibility and benefits of the novel piezoelectric three-legged jumping robot, the present invention proposes a specific embodiment, a piezoelectric robot model is established by simulation software Solidwork, and then the geometric dimensions of each part of the robot are drawn by CAD, and the base of the robot is processed by laser cutting of beryllium copper according to the designed geometric dimensions, and then the piezoelectric ceramic sheet PZT-5H is pasted on the robot base by epoxy resin glue, and 10g uniform force is applied to the pasted piezoelectric ceramic to press for 24 hours to obtain the shape of the robot after pasting, and finally the angle is measured by a protractor and manually bent. The angles between the three legs are all 120° to form a central symmetry, and the angle between the piezoelectric driving leg and the top piezoelectric ceramic sheet is 135°. The dimensions of the piezoelectric robot are shown in Table 1 below.

[0063] Table 1 Parameters and dimensions of the robot

[0064] Parameter Value Quality / g 0.5g TheAngleofthelegstotheplane / (°) 135 <![CDATA[Drivinglegsize / mm 3 ]]> 22×5×0.5 <![CDATA[Robotthree-dimensionalsize / mm 3 ]]> 44×44×16

[0065] A triangular wave is generated by a signal generator and connected to a power amplifier. An electric field is applied to the piezoelectric robot by connecting the piezoelectric driving leg and the base of the piezoelectric robot through a wire, wherein the ceramic piece is connected to the positive electrode and the base of the piezoelectric robot is connected to the negative electrode. The movement speed of the robot is changed by changing the frequency and voltage of different signal generators. When the signal frequency applied to the piezoelectric driving leg is consistent with the resonant frequency of the robot, the displacement of the piezoelectric driving leg reaches the maximum. At this time, the movement displacement of the robot is the largest. The working principle of the robot to generate movement is that the friction force generated by its single leg must be greater than the friction force of the other two legs. However, in this structure, due to the amplifying effect of the top piezoelectric ceramic, the displacement of its single leg is amplified. In this case, the displacement generated by the single leg displacement can drive the other two legs, thereby driving the movement of the entire robot.

[0066] The overall shape of the robot after loading the soft circuit board and battery is as follows Fig. 9 shown.

[0067] Experiments have shown that by applying piezoelectric ceramics to the top, the robot's movement speed is significantly faster. Fig.10 This is a simulation result in Comsol simulation software. By comparing the data, the present invention can find that when the piezoelectric driving leg is driven according to a predefined driving strategy, the single-leg displacement of the piezoelectric driving leg can be significantly increased.

[0068] Further, the simulation is performed in Protues, and the output result of the driving circuit is as follows Figures 11 to 13 As shown, Fig.11 Square wave output, Up-p≤4V, frequency adjustable within 20-20kHz, Fig.12 It is a triangle wave output, Up-p=6V, and the frequency is adjustable within the range of 20-20kHz. Fig.13 It is a sinusoidal wave output, Up-p=1V, and the frequency is adjustable in the range of 20-20kHz. The final result proves that the robot's onboard power supply can be realized by combining with lithium batteries.

[0069] In summary, the present invention has the following beneficial effects:

[0070] By applying piezoelectric ceramics on the top and not applying piezoelectric ceramics on the top, under a predefined control strategy, it can be concluded that the movement speed of the piezoelectric robot is significantly faster when ceramics are applied on the top, and when voltage is applied to the three legs and the top ceramic sheet at the same time, the robot can complete the jumping movement. Compared with other piezoelectric robots, the novel piezoelectric three-legged jumping robot of the present invention has the ability to amplify the displacement of a single leg and the ability to jump. The robot has a faster movement speed, and the three-legged robot has better stability, which is better than the bipedal robot, and is simpler in structure, easier to control and has good stability than the multi-legged robot.

[0071] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A novel piezoelectric three-legged jumping robot, characterized in that: It includes a body and three piezoelectric driving legs, wherein the base shapes of the body and the piezoelectric driving legs are obtained by using laser cutting on beryllium copper, and then the piezoelectric ceramic sheet is pasted on the base using epoxy resin glue, and the piezoelectric driving legs are bent into shape after uniform pressing; The main body is circular, and the three piezoelectric driving legs are evenly distributed on the circumference. The angles between the piezoelectric driving legs are all 120° and are centrally symmetrical. The angle between the piezoelectric driving legs and the horizontal part of the main body is 135°.

2. The novel piezoelectric tripod jumping robot as claimed in claim 1, characterized in that: The main body has a circular piezoelectric ceramic sheet only on the top, and the piezoelectric driving legs have piezoelectric ceramic sheets on the top and bottom. The piezoelectric ceramic sheets on the main body and the piezoelectric driving legs are made of PZT-5H.

3. The novel piezoelectric tripod jumping robot as claimed in claim 2, characterized in that: The novel piezoelectric tripod jumping robot also includes a driving circuit and a lithium battery. The driving circuit is a soft board circuit. Both the driving circuit and the lithium battery can be arranged above the circular piezoelectric ceramic sheet of the body.

4. The novel piezoelectric tripod jumping robot as claimed in claim 3, characterized in that: The driving circuit is designed based on the ICL8038 signal generator and is used to generate three waveforms: triangle wave, sine wave and square wave.

5. A novel piezoelectric three-legged jumping robot control method, used to control the novel piezoelectric three-legged jumping robot as claimed in claim 4, dividing the control period into four time periods t1 to t4, characterized in that: The following steps are involved: Step 1: When t=0~t1, a positive voltage is applied to the circular piezoelectric ceramic piece on the top of the body and the top and bottom of the piezoelectric driving leg respectively, the base of the robot is grounded, the polarization direction of the circular piezoelectric ceramic piece is the same as the direction of the applied voltage, the polarization direction of the top ceramic piece of the piezoelectric driving leg is opposite to the direction of the applied voltage, and the polarization direction of the bottom ceramic piece of the piezoelectric driving leg is the same as the direction of the applied voltage; Step 2: When t=t1-t2, the voltage applied to the circular piezoelectric ceramic and the piezoelectric driving leg is gradually reduced; Step 3: When t=t2-t3, the voltage applied to the circular piezoelectric ceramic piece and the piezoelectric driving leg gradually increases, the polarization direction of the circular piezoelectric ceramic piece is the same as the direction of the applied voltage, the polarization direction of the top ceramic piece of the piezoelectric driving leg is opposite to the direction of the applied voltage, and the polarization direction of the bottom ceramic piece of the piezoelectric driving leg is the same as the direction of the applied voltage; Step 4: When t=t3-t4, the voltage applied to the circular piezoelectric ceramic piece and the piezoelectric driving leg is gradually reduced.

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