Small push-pull piezoelectric robot and control method thereof

Abstract

The invention discloses a small push-pull piezoelectric robot and a control method thereof, and belongs to the field of piezoelectric crawling robots, the small push-pull piezoelectric robot comprises an airborne control module, a mounting platform, a robot base body, a driving element and motion feet; the airborne control module is adhered to the mounting platform, the mounting platform and the robot base body are integrated, the top view of the robot base body is a symmetrical equilateral hexagon, the moving feet are connected with the bottom of the robot base body at a fixed angle, the driving element is adhered to the side surface of the robot base body, and the airborne control module applies excitation voltage to the driving element. When the voltage rises, the driving element is bent and deformed to push the right end of the base body to be lifted to the upper right and the left end of the base body to be pressed to the lower left, when the voltage drops, the driving element restores deformation, the right end of the base body drops, the left end of the base body is pulled rightwards to perform single-step displacement, and the robot realizes planar motion; the small push-pull piezoelectric robot and the control method thereof have the advantages of being simple in structure, high in motion precision and high in environment adaptability.

Description

Technical Field

[0001] The invention belongs to the field of piezoelectric crawling robots, and in particular relates to a small push-pull piezoelectric robot and a control method thereof. Background Art

[0002] Piezoelectric materials have great development potential in the field of small robots due to their excellent electromechanical conversion performance. Piezoelectric robots are mainly used in military, medical and industrial fields. They have the characteristics of fast response, good electromechanical performance and small size. However, traditional piezoelectric robots have slow movement speed, high requirements on manufacturing process, are limited by external energy supply and have poor environmental adaptability.

[0003] The small push-pull piezoelectric crawling robot proposed in the present invention consists of an airborne control module, a mounting platform, a robot base, a driving element, and a moving foot. It has a small size, light weight, simple assembly, and rapid response. The proposed control method realizes the single-degree-of-freedom straight movement of the small push-pull piezoelectric robot through the anisotropic friction principle and the push-pull theory, and realizes self-powering of the robot for the airborne control module through an integrated signal generating circuit, a DC-DC boost circuit, a DC-DC negative pressure circuit, and an operational amplifier circuit, thereby getting rid of dependence on an external power supply. The precise control of the dynamic response frequency is realized by introducing a single zero point compensation circuit in the unipolar operational amplifier circuit, thereby providing a feasible direction for the application and research of small crawling robots. Summary of the invention

[0004] The purpose of the present invention is to provide a small push-pull piezoelectric robot and a control method thereof, aiming to solve the problems of low energy utilization, slow movement speed and inability to operate independently of small crawling robots.

[0005] To achieve the above-mentioned purpose, the present invention provides a small push-pull piezoelectric robot, including an onboard control module, a mounting platform, a robot base, four driving elements, and two moving feet; the onboard control module is fixedly bonded to the mounting platform, the mounting platform and the robot base are integrated, the robot base is an equilateral hexagon in a top view, and the side is six rectangles of the same size, the driving elements are glued to the four front and rear sides of the base, and the moving feet are fixedly connected to the left and right bottoms of the robot base at a certain angle.

[0006] Preferably, the airborne control module includes four parts: a signal generating circuit, a DC-DC boost circuit, a DC-DC negative voltage circuit, and an operational amplifier circuit.

[0007] Preferably, the installation platform is formed into a horizontal installation platform by bending the Z-direction extended edges of the left and right sides of the robot base inward.

[0008] Preferably, the robot base material is brass, with a thickness of 0.2 mm, a side length of 20 mm, a width of 5 mm, and driving elements are respectively attached to the front and rear sides.

[0009] Preferably, the driving element is made of PZT-5H, has a thickness of 0.2 mm, a length of 15 mm, and a width of 5 mm, and is concentrically bonded to the side rectangle.

[0010] Preferably, the moving feet are welded at a fixed angle to the bottom of the left and right sides of the robot base, and are made of brass, with a length of 20 mm, a width of 4 mm, and a thickness of 0.2 mm.

[0011] Preferably, in the control method of the small push-pull piezoelectric robot, the onboard control module sends a periodic PWM voltage signal to stimulate the driving element to deform. In the voltage rising stage, the driving element drives the robot base to bend and deform, and the right moving foot pushes to the right. In the voltage dropping stage, the driving element restores the deformation, the right moving foot falls, and the left moving foot pulls to the right, thereby enabling the small push-pull piezoelectric robot to move straight on the contact surface by powering itself, thereby realizing the cordless operation of the small push-pull piezoelectric robot.

[0012] In the above-mentioned movement, the horizontal straight movement is realized, which includes the following steps:

[0013] Step 1: The onboard control module sends a PWM voltage signal, which is output to the drive element via a wire; t = t a At this moment, the voltage rises rapidly from 0V to the peak value, the driving element bends and deforms, causing the robot base to deform. The moving foot has a fixed angle with the ground. Under the action of friction, the right moving foot is pushed to the right, and the position of the left moving foot remains unchanged.

[0014] Step 2: a <t<t b At this moment, the voltage remains unchanged and the moving foot maintains the shape of the previous step.

[0015] Step 3: t = t b At this moment, the voltage drops from the peak value to 0V, the driving element recovers its deformation, and the robot base recovers. Due to the friction force, the position of the right moving foot remains unchanged, the left moving foot is pulled to the right, and the small push-pull piezoelectric robot moves straight to the right in a single step.

[0016] Step 4: Repeat steps 1 to 3 to drive the small push-pull piezoelectric robot to move horizontally to the right.

[0017] In the motion control, the output PWM voltage signal mainly includes the following steps:

[0018] Step 5: The main control development board of the signal generation circuit of the onboard control module is Seeeduino xiao. The program is written and burned through the Arduino ide editor. The PWM pin of the development board outputs a PWM voltage signal.

[0019] Step 6: The main control chip of the DC-DC boost and negative voltage circuit of the onboard control module is MC34063, which supplies power to the positive and negative ports of the operational amplifier circuit.

[0020] Step 7. The main control chip of the operational amplifier circuit of the onboard control module is OPA277. The signal input port receives the PWM voltage signal sent by the signal generating circuit and outputs the amplified PWM wave signal through the single-stage operational amplifier circuit.

[0021] Step 8: Repeating steps 5 to 7 can enable the onboard control module to continuously output the amplified voltage signal to the driving element, thereby realizing the independent operation of the small push-pull piezoelectric robot.

[0022] Preferably, in the control method of the small push-pull piezoelectric robot, the driving element can be regarded as a capacitive load, resulting in a change in the dynamic response of the system frequency.

[0023] Preferably, in the control method of the small push-pull piezoelectric robot, the signal generating circuit of the onboard control module sends a PWM wave signal with a duty cycle of 50% and a voltage amplitude of 1.1Vpp; the DC-DC boost circuit topology of the onboard control module is a Boost topology, and the DC-DC negative voltage circuit topology is a Buck topology; the operational amplifier circuit of the onboard control module is combined with a single-point compensation circuit to eliminate the influence of the capacitive load on the circuit.

[0024] Beneficial effects of the present invention:

[0025] (1) The present invention proposes a small push-pull piezoelectric robot. The robot base, mounting platform, and moving feet are integrally formed by laser printing and bending, which increases the overall rigidity. The robot is symmetrical front and back and has good stability. The small push-pull piezoelectric robot has the characteristics of small size, light weight, high energy density, and high energy conversion rate.

[0026] (2) The control method proposed in the present invention is based on anisotropic friction theory and a push-pull model to realize the horizontal straight movement of a small push-pull piezoelectric robot; an integrated signal generating circuit, a DC-DC boost circuit, a DC-DC negative pressure circuit, and an operational amplifier circuit are used as an airborne control module, which is loaded on the mounting platform of the robot base, so that the robot can be self-powered and operate, and the robot has higher environmental adaptability and a wider range of applicable occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the specific embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of the small push-pull piezoelectric robot provided by the present invention;

[0029] Figure 2 This is a top view of the small push-pull piezoelectric robot base and driving element provided by the present invention;

[0030] Figure 3 It is a schematic diagram of the moving foot of the small push-pull piezoelectric robot provided by the present invention;

[0031] Figure 4 This is a motion principle diagram of the small push-pull piezoelectric robot provided by the present invention;

[0032] Figure 5 This is a control block diagram of a small push-pull piezoelectric robot provided by the present invention;

[0033] Figure 6 It is a DC-DC boost circuit diagram provided by the present invention;

[0034] Figure 7 It is a DC-DC negative voltage circuit diagram provided by the present invention;

[0035] Figure 8 is an operational amplifier circuit diagram provided by the present invention;

[0036] Figure numerals: onboard control module 1; mounting platform 2; robot base 3; drive elements 4-1, 4-2, 4-3, 4-4; motion feet 5-1, 5-2. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with specific implementations and with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present invention and its application.

[0038] This example discloses a small diamond-shaped push-pull piezoelectric robot and a control method thereof.

[0039] like Figure 1 As shown, the present invention includes an airborne control module 1, a mounting platform 2, a robot base 3, a driving element 4, and a moving foot 5; the airborne control module 1 is fixedly bonded to the mounting platform 2, and the mounting platform 2 and the robot base 3 are integrated, and are formed by bending the left and right sides of the robot base 3 inwardly in the Z direction. Figure 2As shown, the robot base 3 is a regular hexagon in top view, and the front and rear four sides are attached with driving elements 4, and the driving elements 4 are concentric with the front and rear sides of the robot base 3; Figure 3 As shown, the moving feet 5 are connected to the bottom of the left and right sides of the robot base 3 at a fixed angle.

[0040] The airborne control module 1 includes four parts: a signal generating circuit, a DC-DC boost circuit, a DC-DC negative voltage circuit, and an operational amplifier circuit.

[0041] The mounting platform 2, the robot base 3, and the moving foot 5 are all made of brass with a thickness of 0.2 mm.

[0042] The driving element 4 is made of PZT-5H, with a thickness of 0.2 mm, a length of 15 mm, and a width of 5 mm.

[0043] In the above-mentioned movement, the horizontal straight movement is realized, which includes the following steps:

[0044] Step 1: The onboard control module 1 sends a PWM voltage signal, which is output to the drive element 4 via a wire; Figure 4 As shown in (a), t = t a At this moment, the voltage rises rapidly from 0V to the peak value, the driving element 4 bends and deforms, causing the robot base 3 to deform, and the moving foot 5 has a fixed angle with the ground. Under the action of friction, the right moving foot 5-2 is pushed to the right, and the position of the left moving foot 5-1 remains unchanged.

[0045] Step 2: a <t<t b At this moment, the voltage remains unchanged and the motion foot 5 maintains the shape of the previous step.

[0046] Step 3: Figure 4 As shown in (b), t = t b At this moment, the voltage drops from the peak value to 0V, the driving element 4 recovers its deformation, and the robot base 3 recovers. Due to the friction force, the position of the right moving foot 5-2 remains unchanged, and the left moving foot 5-1 is pulled to the right, and the small push-pull piezoelectric robot moves straight to the right in a single step.

[0047] Step 4: Repeat steps 1 to 3 to drive the small push-pull piezoelectric robot to move horizontally to the right.

[0048] like Figure 5As shown, the robot control system includes a micro lithium battery to power the signal generation circuit main control chip Seeeduino xiao and the DC-DC boost and negative pressure circuits. The signal generation circuit sends a PWM voltage signal with adjustable frequency, a duty cycle of 50%, and a voltage amplitude of 1.1Vpp to the operational amplifier circuit. The DC-DC boost circuit and the negative pressure circuit power the chip OPA277 of the operational amplifier circuit. The operational amplifier circuit is connected to the robot through wires. High-speed cameras are placed at dual positions above and in front of the robot to capture the robot's motion trajectory. The high-speed cameras transmit real-time video to the PC for data analysis and processing.

[0049] like Figure 6 As shown, the chip used in the DC-DC boost circuit is MC34063. The positive voltage circuit based on the Boost topology has the following relationship between the input voltage Vcc and the output voltage Vout:

[0050] The D is the duty cycle, R3 and R4 are voltage-dividing resistors, and the duty cycle can be adjusted as needed. By controlling the duty cycle, the circuit boost ratio can be controlled.

[0051] like Figure 7 As shown, the chip used in the DC-DC power module is MC34063, and the negative voltage circuit based on the Buck step-down topology, the relationship between the voltage divider resistors R2, R3 and the output voltage Vout is:

[0052] The Buck circuit outputs negative voltage. Just reverse the inductance in the circuit to ground. The calculation formula is:

[0053] The V sw is the field effect tube conduction voltage, V sw =0.7V, t on is the switch on time, t off is the switch off time, I pk There is a calculation formula:

[0054] like Figure 8 As shown in the figure, the chip used in the signal amplification circuit is OPA277, which is based on a single-stage operational amplifier circuit. In order to eliminate the influence of the dynamic change of the capacitive load of the driving element on the frequency response of the system, a single zero-point compensation circuit is combined on the basis of the single-stage operational amplifier circuit to introduce a zero-point frequency f z :

[0055] R0 is the internal resistance of the op amp chip, CL is the equivalent non-resonant capacitive load capacitance, Figure 7 In the figure, the function of C1 and R6 is to filter out the high-frequency harmonic interference produced by the signal generating circuit. The parallel RF and CF are the feedback resistor and capacitor at the output end of the op amp circuit, and together with the capacitive load, they form a single zero compensation circuit. RISO is the output isolation resistor, and its value is generally between a few ohms and tens of ohms.

[0056] The described small push-pull piezoelectric robot and its control method, the small push-pull piezoelectric robot has the characteristics of simple structure, precise assembly, small size and high energy density. Compared with the traditional method, the control method no longer relies on the signal generator and the power amplifier, achieves cordless operation, and has higher environmental adaptability, which provides a reference idea for the independent operation of the small piezoelectric robot.

[0057] The above is a detailed introduction to the principle and implementation of a small push-pull piezoelectric robot and its control method proposed by the present invention. This specific implementation is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make creative modifications to this implementation as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A small push-pull piezoelectric robot, characterized in that , comprising an onboard control module (1), a mounting platform (2), a robot base (3), a driving element (4), and a moving foot (5); the onboard control module (1) is mounted on the mounting platform (2) and fixedly bonded by epoxy resin glue; the mounting platform (2) and the robot base (3) are integrated and formed by laser cutting and bending; the robot base (3) is an equilateral hexagon in top view, and the side faces are six rectangles of the same size; the driving element (4) comprises driving elements (4-1, 4-2) attached to the front side of the base (2) and driving elements (4-3, 4-4) attached to the rear side; the moving foot (5) comprises a moving foot (5-1) at the left bottom and a moving foot (5-2) at the right bottom of the robot base (3).

2. A small push-pull piezoelectric robot as claimed in claim 1, characterized in that: The onboard control module (1) comprises four parts: a signal generating circuit, a DC-DC boost circuit, a DC-DC negative voltage circuit, and an operational amplifier circuit, and is fixedly bonded to the mounting platform (2).

3. A small push-pull piezoelectric robot as claimed in claim 1, characterized in that: The installation platform (2) is formed into a horizontal installation platform by bending the left and right sides of the robot base (3) extending in the Z direction inward.

4. A small push-pull piezoelectric robot as claimed in claim 1, characterized in that: The robot base (3) is an equilateral hexagon in a top view, made of brass, with a thickness of 0.2 mm, a side length of 20 mm, and a width of 5 mm, with driving elements (4-1, 4-2, 4-3, 4-4) attached to the front and rear sides respectively.

5. A small push-pull piezoelectric robot as claimed in claim 1, characterized in that: The driving elements (4-1, 4-2, 4-3, 4-4) are made of PZT-5H, have a thickness of 0.2 mm, a length of 15 mm, a width of 5 mm, and are co-centrically bonded to the side rectangles.

6. A small push-pull piezoelectric robot as claimed in claim 1, characterized in that: The movement feet (5-1, 5-2) are welded at a fixed angle to the bottom of the left and right sides of the robot base (3), are made of brass, have a length of 20 mm, a width of 4 mm, and a thickness of 0.2 mm.

7. A small push-pull piezoelectric robot and a control method thereof according to claims 1-6, characterized in that: The control method can enable the small push-pull piezoelectric robot to move straight on the contact surface by powering itself, thereby realizing the cordless operation of the small push-pull piezoelectric robot. In the above-mentioned movement, the horizontal straight movement is realized, which includes the following steps: Step 1: The onboard control module (1) sends a PWM voltage signal, and the PWM voltage signal is output to the drive elements (4-1, 4-2, 4-3, 4-4) via wire connections. t=t a At this moment, the voltage rises rapidly from 0V to the peak value, the driving elements (4-1, 4-2, 4-3, 4-4) stretch and bend, causing the robot base (3) to deform. The direction of the friction force is opposite to the direction of the relative motion of the object, the moving foot (5-1) is pushed to the right, and the position of the moving foot (5-2) remains unchanged. Step 2: a <t<t b At this moment, the voltage remains unchanged, and the moving feet (5-1, 5-2) maintain the shape of the previous step. Step 3: t = t b At this moment, the voltage drops from the peak value to 0V, the driving elements (4-1, 4-2, 4-3, 4-4) recover their deformation, the robot base (3) recovers, and due to the friction force, the position of the moving foot (5-1) remains unchanged, the moving foot (5-2) is pulled to the right, and the small push-pull piezoelectric robot moves straight to the right in a single step. Step 4: Repeat steps 1 to 3 to drive the small push-pull piezoelectric robot to move horizontally to the right. In the motion control, the output PWM voltage signal mainly includes the following steps: Step 5: The signal generation circuit of the onboard control module (1) is developed on the Seeeduino xiao main control board. The program is written and burned through the Arduino ide editor. The PWM pin of the development board outputs a PWM voltage signal. Step 6: The DC-DC boost circuit and DC-DC negative voltage circuit main control chip of the onboard control module (1) is MC34063, which supplies power to the main control chip of the operational amplifier circuit. Step 7, the main control chip of the operational amplifier circuit of the airborne control module (1) is OPA277, the signal input port receives the PWM voltage signal sent by the signal generating circuit, and the output end of the single-stage operational amplifier circuit outputs the amplified PWM voltage signal to the driving element (4-1, 4-2, 4-3, 4-4). Step 8: Repeating steps 5 to 7 can enable the onboard control module (1) to continuously output the amplified PWM voltage signal to the driving elements (4-1, 4-2, 4-3, 4-4), thereby achieving independent operation of the small push-pull piezoelectric robot.

8. The control method according to claim 7, characterized in that: In the control method of the small push-pull piezoelectric robot, the driving elements (4-1, 4-2, 4-3, 4-4) can be regarded as capacitive loads, resulting in changes in the dynamic response of the system frequency.

9. The control method according to claim 7, characterized in that: In the control method of the small push-pull piezoelectric robot, the main control chip of the signal generating circuit sends a PWM voltage signal with an amplitude of 1.1 Vpp and a duty cycle of 50%.

10. The control method according to claim 7, characterized in that: In the control method of the small push-pull piezoelectric robot, the DC-DC voltage-boosting circuit topology is a Boost circuit topology, the DC-DC negative voltage circuit topology is a Buck circuit topology, and the main control chip MC34063 is powered by an external micro lithium battery.

11. The control method according to claim 7, characterized in that: In the control method of the small push-pull piezoelectric robot, in order to eliminate the influence of the dynamic change of the capacitive load on the onboard control module (1), the operational amplifier circuit introduces a single-point compensation circuit into a single-stage operational amplifier circuit of the operational amplifier circuit.

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