CN-122006269-A - Control method of optical drive self-excitation unidirectional propulsion device and propeller

CN122006269ACN 122006269 ACN122006269 ACN 122006269ACN-122006269-A

Abstract

The invention relates to the technical field of driving control of intelligent materials for light driving, solves the technical problems that the traditional liquid crystal elastomer propelling devices mostly perform reciprocating explosive movement, the propelling force directions are mutually offset, and unidirectional continuous upward propelling is difficult to realize, in particular to a control method of a self-excited unidirectional propelling device for light driving and a propeller, the power propulsion system comprises a plurality of double-layer liquid crystal elastomer spherical shells which are circumferentially and equally spaced on an integral frame, a liquid crystal elastomer ring is arranged between the double-layer liquid crystal elastomer spherical shells, and the power propulsion system generates stepped upward unidirectional thrust for the propeller in an illumination area. According to the invention, the liquid crystal elastomer ring structure with self-rotation capability is introduced, so that periodic explosive thrust conversion under illumination conditions is realized, and the propeller continuously and unidirectionally propels in fluid environments such as liquid or thin gas, thereby remarkably improving propulsion efficiency and energy utilization rate.

Inventors

ZHOU LIN
HU ZHIJIE
CHEN JUNJIE
LI KAI
YU YONG

Assignees

安徽建筑大学

Dates

Publication Date: 20260512
Application Date: 20260206

Claims (10)

1. An optically driven self-exciting unidirectional thruster comprising a monolithic frame (1) made of light material by a mould forming process, characterized in that it further comprises: The power propulsion system (2) comprises a plurality of double-layer liquid crystal elastomer spherical shells (21) which are circumferentially and equally arranged on the integral frame (1), liquid crystal elastomer rings (22) are arranged between the double-layer liquid crystal elastomer spherical shells (21), and the power propulsion system (2) generates stepped upward unidirectional thrust to the propeller in an illumination area; The double-layer liquid crystal elastomer spherical shell (21) comprises an upper spherical shell (211) and a lower spherical shell (213) which are formed by bending two elastic liquid crystal sheets into a spherical shell shape, and an optical coating (212) for controlling light transmission and response behaviors is coated between the upper spherical shell (211) and the lower spherical shell (213); Sequentially stacking an upper spherical shell (211), an optical coating (212) and a lower spherical shell (213) to form a shallow spherical shell structure and placing the shallow spherical shell structure perpendicular to the illumination direction; The upper spherical shell (211) is in an illumination area in the initial stage, and the upper spherical shell (211) slowly contracts and gradually flattens on a plane due to the photo-thermal effect, when the deformation reaches a limit value, the upper spherical shell (211) is instantaneously changed from a convex state to a concave state, and the jumping process of the upper spherical shell (211) is completed; The lower spherical shell (213) in a convex state is overturned into an illumination area along with the self-rotation of the liquid crystal elastomer ring (22), and the lower spherical shell (213) slowly deforms under illumination and jumps at a limit value, so that elastic energy is released to apply work to the propeller, and the propeller moves upwards; -connection means (3) for adjustable connection between the power propulsion system (2) and the unitary frame (1) and adjustable according to the state of motion of said power propulsion system (2) or the intensity of the illumination to which it is subjected.
2. A light driven self-exciting unidirectional propeller as claimed in claim 1, characterized in that the unitary frame (1) comprises a fixed frame (11) for connecting a double layer liquid crystal elastomer spherical shell (21) and a protective frame (12) for protecting a liquid crystal elastomer ring (22).
3. A light-driven self-excited unidirectional propeller as claimed in claim 2, characterized in that the liquid crystal elastomer ring (22) is a liquid crystal elastomer rod bent into a pre-stressed torus and fixedly connected with the fixed frame (11).
4. A light-driven self-excited unidirectional propeller as claimed in claim 2, characterized in that the connection means (3) comprises a spherical universal joint (31) fixed on the surface of the upper spherical shell (211), and the other end of the spherical universal joint (31) passes through a universal joint fixing groove (32) formed on the fixing frame (11) and is connected with a universal joint fixing frame (33) fixed on the outer side of the fixing frame (11).
5. A control method for implementing an optical drive self-excited unidirectional propeller as claimed in any one of claims 1 to 4, characterized in that the control method comprises the steps of: S1, bending an elastic liquid crystal sheet into a double-layer liquid crystal elastic spherical shell with a shallow spherical shell structure in an initial state, connecting the double-layer liquid crystal elastic spherical shell with a liquid crystal elastic ring, and placing the double-layer liquid crystal elastic spherical shell perpendicular to the illumination direction to form a power propulsion system to obtain a propulsion device with periodic explosive thrust conversion under the illumination condition; S2, establishing a rotation angle control equation of the liquid crystal elastomer ring in a steady state rotation state to obtain the rotation angular velocity of the liquid crystal elastomer ring in the illumination area in a self-turning manner ; S3, establishing a nonlinear dynamics control equation of a double-layer liquid crystal elastomer spherical shell in the power propulsion system, and establishing a photo-thermal strain control equation of the double-layer liquid crystal elastomer spherical shell, wherein the upper spherical shell and the lower spherical shell in the double-layer liquid crystal elastomer spherical shell alternately enter an illumination area to generate self-jump according to a photo-thermal effect; S4, deducing elastic potential energy generated by the double-layer liquid crystal elastomer spherical shell in the self-propelling process based on a photo-thermal strain control equation And speed before self-propulsion occurs ; S5, introducing dimensionless components to obtain the rotation angular velocity after dimensionless treatment Potential energy of elasticity Critical rotational speed ; S6, based on rotational angular velocity Defining propulsion cycle of propulsion device And according to elastic potential energy Critical rotational speed And constructing a control equation for controlling the propulsion device to propel by the upward stepwise unidirectional burst by utilizing the illumination intensity change.
6. The control method according to claim 5, characterized in that in step S2, the specific process comprises the steps of: S21, according to the curvature radius of the liquid crystal elastomer ring Radius of cross section The coordinates of any point at the cross section are adopted To show that the cross-section temperature field of the liquid crystal elastomer ring is calculated The calculation formula is as follows: ; In the formula, A circumferential angle representing any point on the cross section of the spherical shell; Representing the uniform offset of the temperature field; representing the amplitude in the temperature field distributed using a cosine function; Representing the amplitude in the temperature field distributed with a sinusoidal function; s22, according to the cross section temperature field Calculating elastic strain of liquid crystal elastomer ring on its cross section in stable rotation The expression is: ; In the formula, Is the radius of curvature of the liquid crystal elastomer ring; Representing the coefficient of thermal expansion of the elastomeric liquid crystal inversion ring; A characteristic thermal relaxation time representing the inversion ring cross section; Is the rotational angular velocity; is the equivalent light heating rate; S23, based on elastic strain Calculating the driving torque of a liquid crystal elastomer ring And rotational angular velocity The expression is: ; In the formula, The elastic modulus of the liquid crystal elastomer ring; is the rotational damping coefficient.
7. The control method according to claim 5, characterized in that in step S3, the specific process comprises the steps of: S31, establishing a cylindrical coordinate system according to the geometric dimension of the spherical shell of the double-layer liquid crystal elastomer in the initial state The following nonlinear control equation with axisymmetric deformation has the expression: ; ; In the formula, Is a double-layer liquid crystal elastomer elastic modulus of the spherical shell; poisson ratio of the double-layer liquid crystal elastomer spherical shell; Is the thickness of the double-layer liquid crystal elastomer spherical shell in the initial state; representing a cylindrical coordinate system The radial coordinate of the lower part of the frame, The coordinates of the circumference are represented, Representing the position coordinates of the surface in the housing; The curvature radius of the surface in the spherical shell of the double-layer liquid crystal elastomer; the radial film force of the spherical shell of the double-layer liquid crystal elastomer is adopted; The central axis of the shell is symmetrically deflected; S32, making the initial time temperature difference Equal to ambient temperature Obtaining the temperature difference that the upper spherical shell and the lower spherical shell alternately enter the illumination area within the duration t The method comprises the following steps: Along with the rotation of the liquid crystal elastomer ring, the lower spherical shell enters the illumination area from the dark area, and the transient temperature is recorded as Temperature difference The method comprises the following steps: ; Wherein, the To stabilize the mass power density under illumination; is specific heat capacity; is a thermal property time; The duration of time for the lower spherical shell to enter the illumination area from the dark area; along with the rotation of the liquid crystal elastomer ring, the upper spherical shell enters a dark area from an illumination area, and the transient temperature is recorded as Temperature difference The method comprises the following steps: ; Wherein, the The duration of time for the upper spherical shell to enter the dark area from the illumination area; S33, based on photo-thermal strain With temperature difference The proportional relation between the two layers of the spherical shells establishes a photo-thermal strain control equation that the upper spherical shell and the lower spherical shell in the spherical shells alternately enter an illumination area to generate self-jump, and the expression is as follows: ; Wherein, the Is the coefficient of contraction.
8. The control method according to claim 7, characterized by comprising, in step S4: the initial speed of the propulsion device entering the deceleration stage is The time course is Calculating the speed of the propulsion device before self-propulsion occurs The calculation formula is as follows: ; Wherein, the Representing a reference speed; representing the air damping coefficient during propulsion; Representing the mass of the propulsion device; represents the terminal velocity at which gravity and air resistance balance; elastic potential energy generated in self-propelling process of double-layer liquid crystal elastomer spherical shell The method comprises the following steps: ; In the formula, 、、、 Radial and circumferential components of the spherical shell stress and strain in the double-layer liquid crystal elastomer spherical shell respectively.
9. The control method according to claim 5, wherein the propulsion device self-propels a propulsion cycle The method comprises the following steps: ; Wherein, the Is photo-thermal strain after dimensionless treatment; Is the shrinkage coefficient after dimensionless treatment; The mass power density is the stable illumination after dimensionless treatment; the thermal characteristic time after dimensionless treatment; Is the initial phase of the temperature field.
10. The control method according to claim 5, wherein the expression of the control equation is: ; ; Wherein, the An average self-propulsion speed of the propulsion device in a propulsion cycle; Indicating the duration of the advancement of the propulsion device The distance traversed; indicating the initial position of the propulsion device; representing the instantaneous speed of movement of the propulsion device in the propulsion direction; Indicating the cumulative displacement of the propulsion means in the propulsion direction from the initial moment.

Description

Control method of optical drive self-excitation unidirectional propulsion device and propeller Technical Field The invention relates to the technical field of driving control of intelligent materials for optical driving, in particular to a control method of an optical driving self-excitation unidirectional propulsion device and a propeller. Background The existing propulsion device mainly relies on static buoyancy or dynamic lifting force to counteract gravity, so that free movement of upward propulsion is realized. However, the conventional buoyancy device relies on light gas in an air bag to generate lift force, the performance of the buoyancy device is easily influenced by the change of ambient temperature and atmospheric pressure, the stability and the anti-interference capability are poor, and precise maneuvering control is difficult to realize. The power type device relies on continuous mechanical energy output to generate lifting force, the system structure is complex, a plurality of sets of control modules are required to work cooperatively, and the control difficulty and the maintenance cost are increased. Thus, existing propulsion systems still present technical bottlenecks in terms of environmental adaptability, structural simplicity and autonomous operation. In order to break through the limitations, development of a novel driving paradigm which can directly acquire energy from the environment and has autonomous response and regulation capability becomes an important research direction in the technical field of propulsion. In this context, responsive smart materials, in particular elastic Liquid Crystals (LCEs), present great potential. LCE can produce controllable deformation under the stimulus of light, heat, electricity and the like, and provides possibility for flexible propulsion without motor and power supply. The self-driving is realized by absorbing environmental energy (such as light energy), so that the structure can be obviously simplified, and the energy consumption can be reduced. However, the prior art has not fully utilized this feature to innovate the drive mode of the propulsion device. Most of the optical drive systems based on LCE at present are mostly characterized by simple and reciprocating deformation or non-directional jump, and continuous unidirectional propulsion is difficult to realize. Therefore, it is needed to provide a control method based on a light response material, so that the propulsion device can realize continuous directional propulsion under constant illumination, and a new implementation way is provided for the light driving flexible intelligent propulsion device. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a control method of a light-driven self-excitation unidirectional propulsion device and a propeller, and solves the technical problems that most of traditional liquid crystal elastomer propulsion devices reciprocate and burst, the propulsion directions are mutually offset, and unidirectional continuous upward propulsion is difficult to realize. In order to solve the technical problems, the invention provides the technical scheme that the optical drive self-excitation unidirectional propeller comprises an integral frame made of light materials through a die forming process, and the propeller further comprises: The power propulsion system comprises a plurality of double-layer liquid crystal elastomer spherical shells which are circumferentially and equally arranged on the integral frame, liquid crystal elastomer rings are arranged between the double-layer liquid crystal elastomer spherical shells, and the power propulsion system generates stepped upward unidirectional thrust to the propeller in an illumination area; the double-layer liquid crystal elastomer spherical shell comprises an upper spherical shell and a lower spherical shell which are formed by bending two elastic liquid crystal sheets into a spherical shell shape, and an optical coating for controlling light transmission and response behaviors is coated between the upper spherical shell and the lower spherical shell; Sequentially stacking the upper spherical shell, the optical coating and the lower spherical shell to form a shallow spherical shell structure and placing the shallow spherical shell structure perpendicular to the illumination direction; And the connecting device is used for adjustable connection between the power propulsion system and the integral frame and can be adjusted according to the motion state of the power propulsion system or the intensity of illumination. Further, the upper spherical shell is in an illumination area in the initial stage, and slowly contracts on a plane and gradually flattens due to the photo-thermal effect; And along with the self-rotation of the liquid crystal elastomer ring, the lower spherical shell in a convex state is turned over into an illumination area, and at the moment, the lower spherical shell slowl