Miniature soft bionic piezoelectric robot and control method thereof

Abstract

The invention discloses a miniature soft bionic piezoelectric robot and a control method thereof, and belongs to the field of bionic piezoelectric crawling robots, the miniature soft bionic piezoelectric robot comprises a flexible airborne control module, a robot base body, piezoelectric driving elements and motion feet; the flexible airborne control module is bonded to the arc upper layer of the robot base body, the robot base body is in an omega shape, the piezoelectric driving element is a flexible element and is bonded to the arc lower layer of the robot base body, and the moving feet are fixedly bonded to the lower layer unfolding position of the robot base body; the flexible airborne control module applies excitation voltage to the driving element, when the voltage rises, the driving element is bent and deformed to enable the base body to deform, the right end of the base body is lifted to the upper right portion, when the voltage drops, the driving element recovers deformation, the left end of the base body is pulled rightwards to conduct single-step displacement, and single-step displacement of the robot is achieved. The miniature soft bionic piezoelectric robot and the control method thereof have the advantages of being simple in structure, high in circuit integration level, high in response speed and high in environment adaptability.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of bionic piezoelectric crawling robots, and particularly relates to a micro-soft bionic piezoelectric robot and a control method thereof. BACKGROUND

[0002] The piezoelectric material has outstanding electromechanical conversion characteristics, and has shown significant application prospects in the field of micro-soft bionic robots. The piezoelectric bionic robot is mainly applied to the following key fields: medical health, environmental monitoring, industrial micro-operation and research platform, and has the typical characteristics of fast response, excellent electromechanical coupling efficiency and compact structure design. However, the existing micro-soft bionic robot still has some technical bottlenecks: the motion speed is limited, the manufacturing process is complex, the dependence on external power supply system and the environmental adaptability are insufficient, and the like.

[0003] The micro-soft bionic piezoelectric robot provided by the application is composed of a flexible on-board control module, a robot base, a piezoelectric driving element and a motion foot, has the characteristics of compact structure, light weight, high precision, high environmental adaptability and fast response, and the control method is adopted. The inchworm motion principle is used to realize the single-degree-of-freedom linear motion of the micro-soft bionic piezoelectric robot, the flexible on-board control module is integrated with the DC-DC boost circuit and the operational amplifier square wave generating circuit, the self-power supply function of the bionic piezoelectric robot is realized, and the key problem of the dependence of the traditional micro-soft bionic robot on the external power supply is effectively solved. The application provides a new technical path for the autonomous and practical research of the micro-soft bionic robot. SUMMARY

[0004] The application aims to provide a micro-soft bionic piezoelectric robot and a control method thereof, and aims to solve the problems of complex manufacturing process, slow motion speed and external power supply dependence of the micro-soft bionic robot.

[0005] In order to achieve the above-mentioned purpose, the application provides a micro-soft bionic piezoelectric robot, which comprises a flexible on-board control module, a robot base, a piezoelectric driving element and two motion feet.

[0006] Preferably, the on-board control module comprises a DC-DC boost circuit and an operational amplifier square wave generating circuit, and is attached to the upper layer of the circular arc of the robot base.

[0007] Preferably, the robot base is an "Ω"-shaped arc metal substrate made of brass, with a thickness of 0.2 mm, an arc radius of 5 mm, a width of 5 mm, a length of 3 mm at the flattened part, and a flexible piezoelectric material PVDF bonded to the lower layer of the base arc.

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

[0009] Preferably, the piezoelectric driving element is made of PVDF, with a thickness of 28 μm, a length of 15 mm, and a width of 5 mm.

[0010] Preferably, the movement foot is fixedly connected to the lower layer of the left and right flattened parts of the robot base, and the material is polyurethane foam. The movement foot is semi-cylindrical, with the central axis as the boundary, and the friction coefficient is different in the front and back. The diameter of the semi-cylinder is 3mm and the height is 1.5mm.

[0011] Preferably, in the control method of the micro-soft bionic piezoelectric robot, the flexible airborne control module sends a periodic square wave voltage signal to cause the piezoelectric drive element to undergo periodic deformation. During the voltage rising stage, the piezoelectric drive element drives the robot base to stretch and lift toward the right front, the overall center of gravity of the robot is lifted upward, and the right moving foot of the robot is lifted off the ground. During the voltage dropping stage, the piezoelectric drive element restores the deformation, the right moving foot of the robot falls, and the left moving foot is pulled to the right, thereby enabling the micro-soft bionic piezoelectric robot to perform single-degree-of-freedom inchworm-like motion and achieve independent operation without relying on external energy supply.

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

[0013] Step 1: The flexible onboard control module generates a square wave voltage signal. The positive electrode of the flexible onboard control module is connected to the piezoelectric drive element via a wire, and the ground electrode is connected to the robot base via a wire. At time t = 0, the amplitude of the square wave voltage signal is 0, and the micro soft bionic piezoelectric robot is in its initial state.

[0014] Step 2: At t=t1, the square wave voltage rises from 0V to its peak value, the piezoelectric drive element bends and deforms, the robot body lifts to the right front, the right moving foot lifts off the contact surface, and the left moving foot remains in position due to friction.

[0015] Step 3: At t1 < t < t2, the square wave signal voltage remains unchanged, the moving foot maintains the shape of step 1, and the bionic piezoelectric robot does not move.

[0016] Step four, at t=t2, the square wave signal voltage is rapidly decreased from the peak value to 0V, the piezoelectric driving element restores the deformation, the robot base recovers, under the action of friction, the right moving foot position remains unchanged, the left moving foot is pulled to the right by a single step stride, and the micro soft bionic piezoelectric robot realizes single step stride displacement.

[0017] Step five, steps one to four are repeated, so that the micro soft bionic piezoelectric robot can realize linear motion in the horizontal right direction.

[0018] In the motion control, the output frequency adjustable square wave voltage signal mainly comprises the following steps:

[0019] Step six, the DC-DC boost circuit main control chip of the flexible on-board control module is MAX1771, and the op-amp square wave generating circuit is powered.

[0020] Step seven, the op-amp square wave generating circuit main control chip of the flexible on-board control module is OPA454, and the core circuit component of the op-amp square wave generating circuit is a positive and negative voltage feedback network, and the square wave voltage signal is output to the piezoelectric driving element.

[0021] Step eight, steps six to seven are repeated, so that the flexible on-board control module can continuously output square wave voltage signals to the piezoelectric driving element, and the micro soft bionic piezoelectric robot can realize independent operation.

[0022] Preferably, in the control method of the micro soft bionic piezoelectric robot, when the piezoelectric driving element is not driven, it can be regarded as a static capacitor, and when it is driven, it is a variable capacitive load, so that the system frequency dynamic response changes.

[0023] Preferably, in the control method of the micro soft bionic piezoelectric robot, the square wave op-amp generating circuit main control chip outputs square wave voltage signals, the amplitude is 30V p-p , and the duty cycle is 50%.

[0024] Preferably, in the control method of the micro soft bionic piezoelectric robot, the DC-DC boost circuit topology is Boost circuit topology, and the main control chip MAX1771 is powered by a patch type micro lithium battery.

[0025] The present application has the following advantages:

[0026] (1) The present application provides a micro soft bionic piezoelectric robot, the robot base is integrally formed through laser cutting and stamping forming process, the overall stiffness is increased, the robot has an axisymmetric structure and good stability, the micro soft bionic piezoelectric robot has the characteristics of compact structure, light weight, high precision, high environmental adaptability and fast response.

[0027] (2) The control method based on the inchworm motion principle realizes single freedom degree straight motion of the micro-soft bionic piezoelectric robot; the DC-DC voltage boosting circuit and the operational amplifier square wave generating circuit are integrated as the flexible on-board control module, which is loaded on the upper layer of the robot base body arc, so that the robot is free from external power supply limitation, and has higher environmental adaptability and wider application occasions. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0029] Figure 1 is a three-dimensional structure schematic view of the micro-soft bionic piezoelectric robot provided by the application;

[0030] Figure 2 is a front view of the micro-soft bionic piezoelectric robot base body, the piezoelectric driving element and the flexible on-board control module provided by the application;

[0031] Figure 3 is a motion foot schematic view of the micro-soft bionic piezoelectric robot provided by the application;

[0032] Figure 4 is a control block diagram of the micro-soft bionic piezoelectric robot provided by the application;

[0033] Figure 5 is a motion principle diagram of the micro-soft bionic piezoelectric robot provided by the application;

[0034] Figure 6 is a DC-DC voltage boosting circuit diagram provided by the application;

[0035] Figure 7 is an operational amplifier square wave generating circuit diagram provided by the application;

[0036] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings: DETAILED DESCRIPTION

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

[0038] The present example discloses a micro-soft bionic piezoelectric robot and a control method thereof.

[0039] As Figure 1As shown, the present invention comprises a flexible onboard control module (1), a robot base (2), a piezoelectric drive element (3), and a moving foot (4), wherein the robot base (2) is an arc metal substrate in an "Ω" shape; Figure 2 As shown, the flexible onboard control module (1) is bonded to the upper layer of the robot base (2), and the piezoelectric drive element (3) is bonded to the lower layer of the robot base (2); Figure 3 As shown, the movement foot includes the left movement foot (4-1) and (4-2). With the midline of the semi-cylindrical movement foot as the boundary, the front and rear friction coefficients of the robot movement foot are different, and the movement feet are divided into (4-1-1), (4-1-2), (4-2-1), and (4-2-2).

[0040] The flexible airborne control module (1) comprises two parts: a DC-DC boost circuit and an operational amplifier square wave generating circuit.

[0041] The robot base (2) is made of brass, has a thickness of 0.2 mm, an arc radius of 5 mm, a width of 5 mm, and a length of 3 mm at the flattened portion.

[0042] The robot movement feet (4-1) and (4-2) are fixedly adhered to the lower layer of the flattened part of the robot base (1).

[0043] The piezoelectric drive element (3) is made of a flexible piezoelectric material PVDF film with a thickness of 28 μm, a length of 15 mm, and a width of 5 mm, and is co-centrically bonded to the upper arc of the robot base (2).

[0044] In the above-mentioned movement, the horizontal straight movement is realized by the following steps:

[0045] Step 1: Figure 4 The figure shows a control block diagram of a micro soft bionic piezoelectric robot. The flexible onboard control module (1) sends a square wave voltage signal. The positive electrode of the flexible onboard control module (1) is connected to the piezoelectric drive element (3) through a wire, and the ground electrode is connected to the robot base (2) through a wire. Figure 5 As shown in (a), at time t=0, the amplitude of the square wave voltage signal is 0, and the micro soft bionic piezoelectric robot is in the initial state.

[0046] Step 2: Figure 5 As shown in (b), at time t=t1, the square wave voltage rises from 0V to the peak value, the piezoelectric drive element (3) bends and deforms, the robot base (2) lifts to the right front, the right motion foot (4-2) lifts off the contact surface, and the left motion foot (4-1) remains in the same position due to the friction force.

[0047] Step 3: Figure 5(c) as shown, at t1 < t < t2, the square wave signal voltage remains unchanged, the moving foot (4-1, 4-2) maintains the step one form, and the bionic piezoelectric robot does not move.

[0048] Step four, as shown in Figure 5 (d) as shown, at t = t2, the square wave signal voltage rapidly decreases from the peak value to 0V, the piezoelectric driving element (3) restores the deformation, the robot base (2) recovers, under the action of friction, the right moving foot (4-2) position remains unchanged, the left moving foot (4-1) is pulled to the right by a single step distance, and the micro-soft bionic piezoelectric robot realizes single step distance displacement.

[0049] Step five, repeat steps one to four, which can realize driving the micro-soft bionic piezoelectric robot to move linearly in the horizontal right direction.

[0050] As shown in Figure 4 The control flow of the micro-soft bionic piezoelectric robot is that the micro-lithium battery supplies power to the DC-DC boost circuit, the DC-DC boost circuit supplies power to the operational amplifier square wave generation circuit, the positive electrode of the operational amplifier square wave generation circuit is connected to the piezoelectric driving element (3), the negative electrode is connected to the robot base (2), and the laser displacement sensor monitors the robot movement data and transmits it to the upper computer in real time.

[0051] As shown in Figure 6 The chip used in the DC-DC boost circuit is MAX1771, which is a positive voltage circuit based on Boost boost topology, and the relationship between the chip feedback voltage Vref and the output voltage Vout is:

[0052] The R1, R2 are feedback resistors, and the chip feedback voltage Vref = 1.5V.

[0053] The core device of the Boost boost circuit is inductance, and the selection of inductance directly affects the output characteristics of the circuit, and the value formula is:

[0054] The L is the inductance value, ΔI L is the inductance current ripple, f sw is the chip switching frequency, the MAX1771 chip switching frequency is 300KHz, Vin and Vout are the input and output voltages respectively.

[0055] In the design of the voltage boosting circuit, the inductance current ripple is set to be 20% to 40% of the load, the DC-DC voltage boosting circuit of the application supplies power to the operational amplifier square wave generating circuit; the maximum rated power input current of the main control chip OPA454 of the operational amplifier square wave generating circuit is 70mA, in order to ensure the reliability of the system, the load circuit of the voltage boosting circuit is set to be 50mA, and the inductance current ripple value calculation formula is as follows:

[0056] As shown in Figure 7 , the chip used in the operational amplifier square wave generating circuit is OPA454, the R1 and RP2 in the in-phase input end and the output port Vout form a positive feedback network; the capacitor C1 in the reverse input end and the sliding resistor RP1 form a negative feedback network.

[0057] The micro-soft bionic piezoelectric robot and the control method thereof have the characteristics of compact structure, light weight, high precision, high environmental adaptability and fast response. Compared with the traditional method, the control method integrates the boost circuit and the operational amplifier square wave generating circuit as a flexible on-board control module, which is loaded on the upper layer of the robot base arc. The robot is free from external power supply restrictions, has higher environmental adaptability and is more widely applicable.

[0058] The above describes a micro-soft bionic piezoelectric robot and a control method thereof. The principle and implementation of the application are described in detail. The specific embodiment is only an explanation of the application, and is not a limitation of the application. Those skilled in the art can make creative contributions to the modification of the embodiment according to the needs after reading the specification, but as long as it is within the scope of the claims of the application, it is protected by the patent law.

Claims

1. A micro soft bionic piezoelectric robot, characterized in that , comprising a flexible onboard control module (1), a robot base (2), a piezoelectric drive element (3), and a motion foot (4); the flexible onboard control module (1) is bonded to the upper layer of the robot base (2); the robot base (2) is an arc-shaped metal substrate in the shape of "Ω", formed by laser cutting and stamping; the lower layer is bonded with a piezoelectric drive element (3); the piezoelectric drive element (3) is a flexible piezoelectric material; the motion foot (4) is inlaid and connected to the left and right ends of the robot base (2), and comprises a left motion foot (4-1) and a right motion foot (4-2) of the robot base (2).

2. A micro soft bionic piezoelectric robot according to claim 1, characterized in that: The flexible airborne control module (1) comprises a DC-DC boost circuit and an operational amplifier square wave generating circuit, emits a square wave voltage signal with adjustable voltage frequency, and is fixedly attached to the upper surface of the robot base (2).

3. A micro soft bionic piezoelectric robot according to claim 1, characterized in that: The robot base (2) is an "Ω"-shaped arc metal base plate made of brass, with a thickness of 0.2 mm, an arc radius of 5 mm, a width of 5 mm, and a length of 3 mm at the flattened portion. The upper and lower layers are respectively adhered with a flexible airborne control module (1) and a piezoelectric drive element (3). The left and right flattened portions are respectively fixedly connected with a left motion foot (4-1) and a right motion foot (4-2).

4. The micro soft bionic piezoelectric robot according to claim 1, characterized in that: The piezoelectric drive element (3) is made of a flexible piezoelectric material PVDF film with a thickness of 28 μm, a length of 15 mm, and a width of 5 mm, and is co-centrically bonded to the upper arc of the robot base (2).

5. The micro soft bionic piezoelectric robot according to claim 1, characterized in that: The left and right movement feet (4-1, 4-2) are fixedly connected to the lower layers of the left and right flattened parts of the robot base (2), and are made of polyurethane foam.

6. The micro soft bionic piezoelectric robot according to claim 1, characterized in that: The left and right movement feet (4-1, 4-2) are semi-cylindrical and divided into (4-1-1, 4-1-2) and (4-2-1, 4-2-2) with the central axis as the boundary. The front and rear friction coefficients of (4-1-1) and (4-1-2) are different, and the front and rear friction coefficients of (4-2-1) and (4-2-2) are different. The diameter of the semi-cylinder is 3mm and the height is 1.5mm.

7. A micro soft bionic piezoelectric robot and a control method thereof according to claims 1-6, characterized in that: The control method can enable the micro soft bionic piezoelectric robot to perform straight motion with adjustable motion speed on the contact surface by powering itself, thereby realizing offline independent operation of the micro soft bionic piezoelectric robot. In the above-mentioned movement, the horizontal straight movement is realized by the following steps: Step 1: The flexible airborne control module (1) emits a square wave voltage signal. The positive electrode of the flexible airborne control module (1) is connected to the piezoelectric drive element (3) via a wire, and the ground electrode is connected to the robot base (2) via a wire. At time t=0, the amplitude of the square wave voltage signal is 0, and the micro soft bionic piezoelectric robot is in an initial state. Step 2: At t=t1, the square wave voltage rises from 0V to its peak value, the piezoelectric drive element (3) bends and deforms, the robot base (2) lifts to the right front, the right motion foot (4-2) lifts off the contact surface, and the left motion foot (4-1) remains in the same position due to the friction force. Step 3: At the moment t1<t<t2, the square wave signal voltage remains unchanged, the moving feet (4-1, 4-2) maintain the shape of step 1, and the bionic piezoelectric robot does not move. Step 4: At t=t2, the square wave signal voltage drops rapidly from the peak value to 0V, the piezoelectric drive element (3) recovers its deformation, and the robot base (2) recovers. Under the action of friction, the position of the right moving foot (4-2) remains unchanged, and the left moving foot (4-1) is pulled to the right in a single step, and the micro soft bionic piezoelectric robot achieves single-step displacement. Step 5: Repeat steps 1 to 5 to drive the micro soft bionic piezoelectric robot to move horizontally to the right. In the motion control, the output frequency-adjustable square wave voltage signal mainly includes the following steps: Step 6: The DC-DC boost circuit main control chip of the flexible airborne control module (1) is MAX1771, which supplies power to the operational amplifier square wave generating circuit. Step 7: The main control chip of the operational amplifier square wave generating circuit of the flexible airborne control module (1) is OPA454. The core circuit component of the operational amplifier square wave generating circuit is the positive and negative voltage feedback network, and the square wave voltage signal is output to the piezoelectric driving element (3). Step 8: Repeating steps 7 to 8 can enable the flexible airborne control module (1) to continuously output square wave voltage signals to the piezoelectric drive element (3), thereby achieving independent operation of the micro soft bionic piezoelectric robot.

8. The control method according to claim 6, wherein: In the control method of the micro soft bionic piezoelectric robot, the piezoelectric driving element (3) can be regarded as a static capacitor when not driven, and as a variable capacitive load when driven, resulting in a change in the system frequency dynamic response.

9. The control method according to claim 6, wherein: The control method of the micro soft bionic piezoelectric robot, the main control chip of the square wave op amp generating circuit sends a square wave voltage signal with an amplitude of 30V p-p , the duty cycle is 50%.

10. The control method according to claim 6, characterized in that: The control method of the micro soft bionic piezoelectric robot is characterized in that the DC-DC boost circuit topology is a Boost circuit topology, which supplies power to the operational amplifier square wave generating circuit, and the main control chip MAX1771 is powered by a patch-type micro lithium battery. In order to eliminate the influence of the dynamic change of the capacitive load on the flexible airborne control module (1), the square wave generating circuit introduces an RC network at the output end of the square wave generating circuit to avoid zero point drift caused by the dynamic change of the capacitive load.

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