Optical drive planar tension self-excited oscillation control system and control method thereof

Abstract

The present application relates to the technical field of vibration system, especially to a CD drive planar tension self-excited oscillation control system and a control method thereof; by connecting the photothermal elastic element and the passive elastic element to tension the vibration mass point, and combining with the light source irradiation to form the light irradiation area, a planar tension self-excited oscillation control system with simple structure and without external periodic excitation is constructed, the vibration mass point can be driven to continuously and stably self-excited oscillate under constant light, the system realizes self-sufficient energy and cable-free operation, has the ability to resist electromagnetic interference, and is suitable for microgravity and weightless environment; the control method of the present application constructs the CD strain equation and the vibration mass point motion equation based on the measured deformation curve of the photothermal elastic element, solves the target control parameter set through dimensionless processing, realizes the accurate design and pre-control of the system oscillation amplitude, frequency and motion trajectory, and each parameter can be independently or cooperatively adjusted, which significantly improves the controllability and applicability of the system.

Description

Technical Field

[0001] This invention relates to the field of vibration system technology, and in particular to a self-excited oscillation control system and control method for optical drive planar tensioning. Background Technology

[0002] Oscillation is a fundamental and ubiquitous physical form in energy conversion and transfer, widely existing at all levels from macroscopic engineering systems to microscopic natural phenomena. In engineering technology and applications, high-performance oscillators are core components for achieving precise motion control, efficient information transmission, and stable power output. Their performance directly determines the reliability, control accuracy, and energy efficiency of the entire system.

[0003] However, the driving mechanisms of traditional oscillators currently in widespread use mainly rely on mechanical excitation, electromagnetic induction effect, or piezoelectric coupling principle. These methods generally require an externally connected periodic excitation source or a complex alternating power supply system, and usually must be paired with precise feedback and control circuits to maintain a continuous and stable oscillation state. This inherent design pattern not only makes the oscillator itself susceptible to interference from the external electromagnetic environment, affecting its working stability, but more importantly, it fundamentally restricts the autonomy of the related system in terms of energy supply, hindering the further development of the system towards lightweight, integrated, and cableless directions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a planar tension self-excited oscillation control system and its control method for optical drives, which solves the technical problems that the driving mechanism of traditional oscillators is easily affected by external electromagnetic interference and is difficult to achieve lightweight design.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a planar tension self-excited oscillation control system for optical drives, comprising a vibrating mass and a mounting frame as a mounting carrier, and further comprising: At least two passive elastic elements capable of elastic expansion and contraction, one end of which is connected to the vibrating mass and the other end of which is connected to the mounting frame; At least one photothermal elastic element that can be stretched and contracted by photothermal drive, with one end connected to the vibrating mass and the other end connected to the mounting frame; A light-illuminating area is formed by irradiating a portion of the photothermal elastic element in its initial state. This area is used to drive the photothermal elastic element to expand and contract and cooperate with multiple passive elastic elements to make the vibrating particles continuously self-excited oscillate or remain still.

[0006] A control method for a planar tension self-excited oscillation control system for an optical drive includes: Obtain the light-driven strain equation of a photothermal elastic component under both illuminated and unilluminated conditions when it is under tension; The motion equation of the vibrating particle is established based on the optically driven strain equation of the planar tension self-excited oscillation control system and the photothermal elastic component. Based on the motion equation of the vibrating particles, the target control parameter set of the system's vibrating particles when satisfying the preset vibration state is solved; the target control parameter set includes at least one of the following: dimensionless prestress, dimensionless light intensity, dimensionless elastic coefficient of the passive elastic element, dimensionless damping coefficient, thermal relaxation time ratio, and illumination angle range. Based on the target control parameter set, adjust the parameters of the planar tension self-excited oscillation control system to drive the vibrating particles to achieve the preset vibration state.

[0007] Preferably, the specific steps for obtaining the optical drive strain equation are as follows: To ensure that the photothermal elastic component remains taut under both light and non-light conditions; The photothermal elastic element was irradiated by the illuminated area, and the length of the photothermal elastic element was recorded as a function of illumination over time. Remove the illuminated area and record the non-illuminated curve of the length of the photothermal elastic element over time; The light-driven strain equation of the photothermal elastic element is constructed based on the illumination change curve and the non-illumination change curve.

[0008] Preferably, the equation of motion of the vibrating particle is constructed based on its mass, the instantaneous tension of the passive elastic element, the instantaneous tension of the photothermal elastic element, and the damping coefficient. The instantaneous tension of the photothermal elastic element is calculated based on the product of its instantaneous deformation and the equivalent elastic coefficient. The instantaneous deformation of the photothermal elastic element is obtained by calculating the difference between its instantaneous length and the optical drive balance length. The optical drive balance length is calculated based on its optical drive strain equation and original length. The instantaneous tension of the passive elastic element is calculated based on the product of its instantaneous deformation and elastic coefficient.

[0009] Preferably, when solving for the target control parameter set, the motion equations are dimensionless to obtain dimensionless control equations, and the target control parameter set is obtained by solving the dimensionless control equations.

[0010] Preferably, the preset vibration state includes a static state and a periodic self-excited oscillation state; the periodic self-excited oscillation state is when the vibrating particle reciprocates according to a preset trajectory and velocity.

[0011] A computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the steps of the control method for the planar tension self-excited oscillation control system.

[0012] By means of the above technical solution, the present invention provides a planar tension self-excited oscillation control system and control method for optical drives, which has at least the following beneficial effects: 1. This invention constructs a planar tension self-excited oscillation control system that is lightweight and does not require external periodic excitation by coordinating the tensioning of vibrating particles with photothermal elastic elements and passive elastic elements, and forming an illuminated area by combining light source illumination. Under constant illumination, it can drive vibrating particles to perform continuous and stable self-excited oscillation, realize the system's energy self-sufficiency and cableless operation, have anti-electromagnetic interference capabilities, and are suitable for microgravity and zero-gravity environments.

[0013] 2. The control method of the present invention constructs the optical drive strain equation and the motion equation of the vibrating particle based on the measured deformation curve of the photothermal elastic component. The target control parameter set is solved by dimensionless processing, realizing the precise design and pre-control of the system oscillation amplitude, frequency and motion trajectory. Each parameter can be adjusted independently or collaboratively, which significantly improves the controllability and applicability of the system.

[0014] 3. This invention transforms the inherent photothermal relaxation hysteresis of LCE materials into a favorable phase difference required to maintain self-excited oscillations. By periodically moving the photothermal elastic element into and out of the illumination region, a dynamic balance between energy input and damping dissipation is achieved, ensuring long-term stable operation of the system under constant illumination and overcoming the constraint of material response hysteresis on continuous oscillation.

[0015] 4. This invention can flexibly adjust parameters such as dimensionless prestress, light intensity, elastic coefficient, damping coefficient, thermal relaxation time ratio, and illumination angle range to adapt to the requirements of different application scenarios for oscillation amplitude, frequency, and energy consumption, thus broadening its application prospects in soft robot joint drive, wireless sensor network power supply, and microgravity environment actuation. Attached Figure Description

[0016] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the planar tension self-excited oscillation control system of the present invention; Figure 2 The diagram shows the experimental characteristics of the photothermal response of the LCE fiber of this invention. Figure 2 (a) is a diagram of the experimental setup in the initial state without light. Figure 2 (b) is a diagram of the experimental setup under the illumination stripe. Figure 2 (c) is a graph showing the length variation of LCE fibers under illumination conditions. Figure 2 (d) is a graph showing the length change of LCE fibers after they are removed from the light source; Figure 3This is a simplified structural diagram of the present invention in a two-dimensional coordinate system. Figure 3 (a) is a schematic diagram of the system in a two-dimensional coordinate system in its initial state. Figure 3 (b) is a schematic diagram of the system in a two-dimensional coordinate system during the vibration process; Figure 4 This is a comparison diagram of the static mode and the periodic self-oscillation mode of the planar tension self-excited oscillation control system of the present invention, wherein, Figure 4 (a) is a motion trajectory diagram in static mode. Figure 4 (b) is the trajectory diagram under the periodic self-oscillation mode. Figure 4 (c) is the time history curve in the x-direction under static mode. Figure 4 (d) is the time history curve in the x-direction under periodic self-oscillation mode. Figure 4 (e) is the time history curve in the y-direction under static mode. Figure 4 (f) is the time history curve in the y-direction under periodic self-oscillation mode. Figure 4 (g) is the phase diagram in the x-direction under static mode. Figure 4 (h) is the phase diagram in the x-direction under periodic self-oscillation mode. Figure 4 (i) is the y-direction phase diagram in the static mode. Figure 4 (j) is the y-direction phase diagram under periodic self-oscillation mode; Figure 5 This is a schematic diagram of the self-vibration mechanism of the planar tension self-excited oscillation control system of the present invention, wherein, Figure 5 (a) is a motion trajectory diagram. Figure 5 (b) is a graph showing the periodic shrinkage and recovery of LCE fiber length over time. Figure 5 (c) is a periodic fluctuation diagram of the elasticity of LCE fibers over time. Figure 5 (d) is a graph showing the periodic variation of damping force over time. Figure 5 (e) is a diagram showing the work done by the elastic force of LCE fibers in the x-direction. Figure 5 (f) is the work done by the damping force in the x-direction. Figure 5 (g) is a work diagram of the elastic force of LCE fibers in the y direction. Figure 5 (h) is the work done by the damping force in the y direction; Figure 6 This invention relates to the limit rings under different prestresses and their influence on the system's self-excited vibration frequency and motion trajectory. Figure 6 (a) is the phase diagram in the x-direction under different prestresses. Figure 6 (b) is the phase diagram in the y-direction under different prestresses. Figure 6 (c) shows the motion trajectory diagrams under different prestresses. Figure 6 (d) is a graph showing the trend of the perimeter and frequency of the motion trajectory as a function of prestress; Figure 7This invention relates to the limiting cycle under different light intensities and its influence on the system's self-excited vibration frequency and motion trajectory. Figure 7 (a) is the phase diagram of the x-direction under different light intensities. Figure 7 (b) is the phase diagram of the y-direction under different light intensities. Figure 7 (c) shows the motion trajectory under different light intensities. Figure 7 (d) is a graph showing the trend of the perimeter and frequency of the motion trajectory as a function of light intensity; Figure 8 This invention relates to the limiting loops of different elastic ropes and their effects on the system's self-excited vibration frequency and trajectory. Figure 8 (a) is the phase diagram in the x-direction for different elastic coefficients of the elastic ropes. Figure 8 (b) is the phase diagram in the y-direction for different elastic coefficients of the elastic ropes. Figure 8 (c) shows the motion trajectory diagrams under different elastic coefficients of the ropes. Figure 8 (d) is a graph showing the trend of the circumference and frequency of the motion trajectory as a function of the elastic coefficient of the elastic rope; Figure 9 This invention relates to the limit cycle under different damping conditions and its influence on the system's self-excited vibration frequency and trajectory. Figure 9 (a) is the phase diagram in the x-direction under different damping conditions. Figure 9 (b) is the phase diagram in the y-direction under different damping conditions. Figure 9 (c) shows the motion trajectory under different damping conditions. Figure 9 (d) is a graph showing the trend of the perimeter and frequency of the motion trajectory as a function of damping; Figure 10 This invention relates to the limiting cycle under different thermal relaxation time ratios and its influence on the system's self-excited vibration frequency and motion trajectory. Figure 10 (a) is the phase diagram in the x-direction under different thermal relaxation time ratios. Figure 10 (b) is the phase diagram in the y-direction for different thermal relaxation time ratios. Figure 10 (c) shows the motion trajectory diagrams under different thermal relaxation time ratios. Figure 10 (d) is a graph showing the trend of the perimeter and frequency of the motion trajectory as a function of the thermal relaxation time ratio; Figure 11 This invention relates to the limit cycle under different illumination angle ranges and its influence on the system's self-excited vibration frequency and motion trajectory. Figure 11 (a) is the phase diagram in the x-direction under different illumination angle ranges. Figure 11 (b) is the phase diagram of the y-direction under different illumination angle ranges. Figure 11 (c) shows the motion trajectory under different illumination angle ranges. Figure 11 (d) is a graph showing the trend of the perimeter and frequency of the motion trajectory as a function of the illumination angle range.

[0017] In the diagram: 1. Vibrating particle; 2. Mounting frame; 3. Passive elastic component; 4. Photothermal elastic component; 5. Illuminated area. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This will allow for a full understanding of how the present application uses technical means to solve technical problems and achieve technical effects, and to facilitate its implementation.

[0019] Currently, biological systems in nature exhibit highly efficient and autonomous periodic motion capabilities. Their active tissues, such as muscles, can directly convert constant chemical energy into continuous mechanical oscillations. The entire process relies on the intrinsic coupling between material response and system dynamics, requiring no external real-time intervention. Inspired by this, developing novel actuators that can extract energy from a constant environment and achieve self-sustaining oscillations through internal nonlinear feedback has become a key research direction in fields such as optically driven LCE robots, soft robots, and programmable intelligent structures.

[0020] The key to realizing such self-excited oscillators lies in developing smart materials capable of generating significant mechanical responses to constant external stimuli. In recent years, a series of stimulus-responsive polymer materials, such as liquid crystal elastomers (LCEs), dielectric elastomers, shape memory polymers, thermally responsive polymers, ionogels, and hydrogels, have attracted widespread attention due to their ability to undergo significant, reversible, and programmable macroscopic deformations under external physical fields (such as light, electricity, heat, magnetism, and chemical fields), providing a rich material basis for this research. Among them, LCEs, through molecular orientation programming, can generate large-amplitude, reversible, and directionally controllable deformations under stimuli such as light and heat, while also possessing flexibility, high energy density, and muscle-like movement characteristics, making them considered ideal "artificial muscle" materials for constructing biomimetic self-propelled systems. Based on LCEs, research has achieved various self-propelled movements such as vibration, rolling, rotation, contraction, torsion, flexion, bending, jumping, oscillation, shuttle movement, and levitation. However, using LCEs to construct self-excited oscillators operating under constant stimuli still faces fundamental challenges: the inherent photothermal relaxation hysteresis of LCE materials results in a significant time delay in their deformation response and recovery relative to changes in stimulus. This hysteresis typically leads the system to tend towards static equilibrium or generates irregular relaxation fluctuations, making it difficult to form stable, periodic oscillations. Although existing theoretical models have revealed various potential self-excited oscillation modes, overcoming the material hysteresis effect in experiments and achieving long-term stable self-sustaining oscillations remains the core bottleneck in the transition from theory to practical application in this field.

[0021] To overcome the limitations at the material level, this embodiment draws inspiration from tension structures in nature (such as spider webs). These structures, through the synergistic coupling of fibers of different stiffness under pretension, can efficiently transform local disturbances into specific modal vibrations of the structure, and maintain the dynamic process by relying on their own energy storage and release mechanisms. Inspired by this, to address the technical problems of traditional oscillators being easily affected by external electromagnetic interference and difficult to achieve lightweight design, this embodiment provides a light-driven planar tension self-excited oscillation control system. This system possesses advantages such as a simple and lightweight design, energy self-sufficiency, high driving efficiency, and resistance to electromagnetic interference, cableless operation, and miniaturization. It provides a novel light-driven self-excited oscillator solution for fields such as micro-cableless robots, wireless sensing, and microgravity environment actuation. Figure 1 As shown, the planar tension self-excited oscillation control system includes a vibrating mass and an installation frame as the mounting carrier. It also includes: at least two passive elastic elements 3 capable of elastic expansion and contraction, one end of which is connected to the vibrating mass 1 and the other end to the installation frame 2; at least one photothermal elastic element 4 capable of expansion and contraction via photothermal drive, one end of which is connected to the vibrating mass 1 and the other end to the installation frame 2; and an illumination area 5 formed by light source illumination covering a portion of the photothermal elastic element 4 in its initial state, used to drive the photothermal elastic element 4 to expand and contract and cooperate with the multiple passive elastic elements 3 to cause the vibrating mass 1 to undergo continuous self-excited oscillation or remain stationary. In this embodiment, the passive elastic element 3 has elastic expansion and contraction capabilities and can be made of elastic fiber; the photothermal elastic element 4 has photothermal response characteristics and can be made of LCE fiber. The following detailed description is based on this material selection. Figure 1 As shown, taking the example of two passive elastic elements 3, one photothermal elastic element 4, and three points of the passive elastic elements 3 and 4 on the mounting frame 2 forming an equilateral triangle, with the vibrating mass 1 located at the centroid of the equilateral triangle, the side length of the equilateral triangle is L. A coordinate system is established for explanation and calculation, as follows. Figure 3 As shown, The corresponding components represent photothermal elastic components. The components corresponding to b and c are passive elastic components. When the vibrating particle 1 vibrates, it vibrates in a trajectory similar to an ellipse in three-dimensional space. At the same time, the photothermal elastic component 4 reciprocates in and out of the illuminated area 5.

[0022] To further achieve precise control of the planar tension self-excited oscillation control system and enable the vibrating particles to vibrate in a preset vibration state, this embodiment further provides a control method for the optical drive planar tension self-excited oscillation control system, including: S1. Obtain the optical drive strain equation of the photothermal elastic component under both illuminated and unilluminated conditions when it is under tension. The process of establishing the optical drive strain equation is described in detail below: like Figure 2As shown, in this embodiment, through LCE characteristic experiments, the deformation curves of LCE fibers under illumination and non-illumination conditions were measured and plotted, and the expression for the optical drive strain of LCE fibers was obtained, as follows. Figure 2 As shown in (a), the experiment used an LCE fiber with a diameter of 0.8 mm and a length of 17 cm, from which a 1.8 g mass ball was suspended to keep it taut at all times. Figure 2 As shown in (b), after the mass sphere has stabilized, a 9cm long strip of light is emitted from an 808nm near-infrared laser under moderate illumination, stably illuminating the middle of the LCE fiber to form an illuminated area. The infrared laser is then turned off to remove the illuminated area, and the LCE fiber resumes its elongation deformation. The deformation process of the LCE fiber is recorded using imaging technology, obtaining its relative length change curves over time under illuminated and unilluminated conditions, as shown in the figure. Figure 2 As shown in (c) and (d), the light-driven strain equation of the photothermal elastic element can finally be constructed based on the relative length change curves under illumination and non-illumination conditions.

[0023] Let the relative length of LCE fibers be... ,in, The instantaneous length of the LCE fiber. Let be the original length of the LCE fiber, and its change with time t can be fitted to the following exponential form: (1) Corresponding photothermal driven strain as a function of time t for: (2) For ease of theoretical analysis, a general form of the optical drive strain equation is defined: (3) in, Represents the optical power correlation coefficient. and The ratio of the thermal relaxation times under illumination and non-illumination conditions represents the thermal relaxation time. Defined as the thermal relaxation time ratio, it reflects the difference between the rates of heating and cooling of the material. In this embodiment... This indicates that the photo-induced shrinkage rate is approximately 1.6 times the recovery rate.

[0024] S2. Establish the motion equation of the vibrating particle based on the planar tension self-excited oscillation control system and the optically driven strain equation of the photothermal elastic component.

[0025] In this embodiment, as Figure 3 As shown in (a), in the initial state, both the photothermal elastic element and the passive elastic element are subjected to equal prestress T. This indicates a photothermal elastic component; b and c are both passive elastic components, such as... Figure 2As shown in (b), under constant strip illumination, an illumination area is formed on the LCE fiber. The LCE fiber contracts and pulls the mass point away from the initial equilibrium position, simultaneously causing the two elastic fibers to undergo tensile deformation. The entire three-line tension configuration changes. The LCE fiber moves out of the illumination area and recovers its deformation. The elastic fiber releases elastic potential energy, pulling the LCE fiber back to the illumination area and causing it to contract and deform. Under the action of inertial force, it eventually exhibits periodic self-excited oscillation behavior.

[0026] The forces acting on the vibrating particle mainly include the tension and damping forces of the photothermal elastic element and the passive elastic element. Gravity affects the equilibrium position and trajectory of the oscillation but has no significant effect on the oscillation characteristics, so it can be ignored in the theoretical analysis. In this case, the equation of motion of the vibrating particle is constructed based on its mass, the instantaneous tension of the passive elastic element, the instantaneous tension of the photothermal elastic element, and the damping coefficient, and can be written as: (4) in, and These are the x and y coordinates of the vibrating particle, respectively. and They are respectively The first and second derivatives, and They are respectively The first and second derivatives, This refers to the damping coefficient, such as the air damping coefficient. , and They represent photothermal elastic components respectively. The component of the instantaneous tension in the passive elastic elements b and c in the x-direction. , and They represent photothermal elastic components respectively. The formula for calculating the component of the instantaneous tension in the y-direction of passive elastic elements b and c is as follows: (5) Among them, photothermal elastic components instantaneous tension Based on its instantaneous deformation and equivalent elastic coefficient The product calculation of photothermal elastic components The instantaneous deformation is calculated by measuring its instantaneous length. Balanced length with optical drive The difference is obtained, and the instantaneous tensions of passive elastic elements b and c are calculated based on the product of their instantaneous deformation and elastic coefficient. The calculation formulas for the three can be expressed as follows: (6)

[0027] in, , , and These represent the instantaneous tension, elastic modulus, instantaneous length, and original length of the passive elastic element b, respectively. , , and Let denot represent the instantaneous tension, elastic coefficient, instantaneous length, and original length of the passive elastic element c, respectively, and the optical drive equilibrium length at any time t. Based on the optical drive strain equation and its original length The calculation formula is as follows: (7) In addition, photothermal elastic components The instantaneous lengths of passive elastic elements b and c at any time t are obtained from their coordinates in the coordinate system and their geometric relationships, and the calculation formula is as follows: (8)

[0028] S3. Based on the equation of motion of the vibrating particles, solve for the target control parameter set of the system's vibrating particles when they meet the preset vibration state. The target control parameter set must include at least one of the following: dimensionless prestress, dimensionless light intensity, dimensionless elastic coefficient of the passive elastic element, dimensionless damping coefficient, thermal relaxation time ratio, and illumination angle range. When solving for the target control parameter set, the equation of motion is first made dimensionless to obtain the dimensionless control equation for easier calculation. Specifically, the following dimensionless parameters are first introduced: ,in, Represents the dimensionless coordinates in the X direction. Represents the dimensionless coordinate in the Y direction. Represents dimensionless time. Represents the elastic coefficient. This represents the dimensionless damping coefficient. This indicates dimensionless prestress. This indicates LCE fiber a (i.e., photothermal elastic element) The instantaneous length of ) This represents the instantaneous length of elastic fiber b (i.e., passive elastic element b). This represents the instantaneous length of the elastic fiber c (i.e., the passive elastic element c). This represents the original length of LCE fiber a (i.e., photothermal elastic element a). This represents the original length of the elastic fiber b (i.e., the passive elastic element b). Indicates the original length of elastic fiber c. This indicates the equilibrium length of the LCE fiber driven by photothermal processes.

[0029] After defining these dimensionless parameters, the equations of motion are made dimensionless to obtain the dimensionless governing equations, the expressions of which are as follows:

[0030]

[0031] in:

[0032] The dimensionless governing equations are difficult to solve analytically. Therefore, this embodiment employs a numerical method, using a Matlab program to solve them. The classical fourth-order Runge-Kutta equations are numerically integrated to obtain numerical solutions for the displacements of the vibrating particle in the x and y directions. To ensure the reliability of the numerical simulation, this embodiment performs convergence analysis on the step size. By comparing the calculation results under different step sizes, it is found that a step size of 0.001 produces stable and convergent results, and the difference is negligible compared to smaller step sizes.

[0033] Furthermore, based on the numerical solution of the dimensionless governing equations, the system mainly exhibits two typical dynamic states: a static state and a periodic self-excited oscillation state. The periodic self-excited oscillation state is the state in which the vibrating particle reciprocates along a preset trajectory and velocity. These two states can be used as preset vibration states. Before setting parameters, one must first consider the preset vibration state that the vibrating particle wants to achieve in order to adjust the parameters in the target control parameter set. To quantitatively describe the range of motion of the vibrating particle in the plane, this embodiment introduces the perimeter of the motion trajectory as a key indicator, which is defined as the total length of the trajectory curve of the particle in one complete cycle. This parameter intuitively reflects the amplitude and spatial scale of the oscillation. The parameters of the static state and the periodic self-excited oscillation state are explained below: (1) Static state.

[0034] In this embodiment, the dimensionless parameters of the system are fixed as follows: When the dimensionless light intensity At that time, the system is in a static state. For example... Figure 4 As shown in (a), (c), and (e), in the initial stage of illumination, the LCE fiber undergoes photothermal contraction, causing displacement of the traction particles, and the motion trajectory exhibits a small initial reciprocating motion. However, because the energy input to the optical drive is lower than the system's damping dissipation, the displacement rapidly decays over time, as... Figure 4 As shown in (c) and (e), the circumference of the trajectory It also shrinks accordingly and eventually approaches zero. For example... Figure 4 As shown in (g) and (i), the corresponding phase diagrams in the x and y directions show that the phase trajectories converge to a fixed point and do not form a closed curve, indicating that the system eventually reaches static equilibrium and there is no continuous oscillation output.

[0035] (2) Self-excited oscillation state.

[0036] When the dimensionless light intensity increases to exceed the critical value At this point, the system is excited into a periodic self-excited oscillation state. For example... Figure 4 As shown in (b), (d), and (f), after the LCE fiber shrinks, the vibrating particles undergo regular and continuous reciprocating motion in the plane, with stable periodic fluctuations in their x and y displacements. The corresponding motion trajectories form a clear, closed elliptical loop, as shown in (b), (d), and (f). Figure 4 As shown in (b), the trajectory circumference Maintaining a constant non-zero value indicates that the system has achieved stable finite-amplitude oscillations. For example... Figure 4 As shown in (h) and (j), these are phase diagrams in the x and y directions, where closed limit cycles are formed, further confirming from a dynamic perspective that the system is in a stable periodic self-excited oscillation mode.

[0037] In summary, by comparing the shape and circumference of the trajectory under the two states... The evolution of the system can clearly define its behavioral patterns: in a static state... In the state of self-excited oscillation, the system energy tends to dissipate; while in the state of self-excited oscillation... The light intensity is constant and positive. The system achieves a dynamic balance between light energy input and mechanical dissipation to maintain periodic motion. The two modes can be switched by adjusting the light intensity.

[0038] To further reveal the physical essence of the system maintaining stable self-excited oscillations under constant illumination, its intrinsic mechanism is systematically explained from the perspective of energy balance and geometric feedback. Figure 5 The time-series curves and power graphs of a set of key physical quantities are presented, clearly revealing that the core of maintaining self-excited oscillation lies in the fact that the system, through its unique structural design, precisely uses the energy input by photothermal drive within one cycle to compensate for the mechanical energy dissipation caused by damping, thereby achieving dynamic equilibrium.

[0039] Figure 5 (a)-(d) visually demonstrate the dynamic process and energy conversion of the system within a steady-state period. Figure 5 (a) indicates that the system is in periodic motion. Figure 5 (b) The periodic expansion and contraction of the LCE fiber length is a direct reflection of the intermittent injection and interruption of light energy: the contraction phase corresponds to the conversion of light energy into mechanical energy and elastic potential energy, while the recovery phase corresponds to the interruption of the driving force. This process directly leads to Figure 5 (c) The elastic force provided by the LCE fibers exhibits periodic fluctuations, and this force is the direct source of the system's motion and work. Meanwhile, Figure 5(d) shows that the damping force, which is opposite to the velocity direction, also changes periodically, representing the continuous energy dissipation path of the system.

[0040] Figure 5 The net work analysis of (e)-(h) provides quantitative evidence for this energy balance. Figure 5 (e) and Figure 5 (f) The curves showing the variation of LCE fiber force with displacement in the x and y directions are plotted. Both curves form closed loops in a clockwise direction, and the positive areas enclosed by them (0.0017 and 0.0006) represent the net positive work done by the photothermal driving force on the system over one complete cycle, i.e., the net energy input obtained by the system from illumination. For comparison, Figure 5 (g) and Figure 5 (h) plots the work curve of the damping force in the corresponding direction, and the negative area (-0.0017 and -0.0006) enclosed by the closed loop represents the energy consumed by the damping in one cycle.

[0041] The key conclusion is that the positive work input is numerically equal to the negative work consumed, directly verifying that energy conservation holds true within a period. Therefore, the system, through ingenious triple-tensioned geometric feedback, transforms constant illumination into a periodic drive of the LCE fiber, enabling the energy input to match the correct phase and amplitude and offset damping dissipation. This mechanism, based on energy periodic balance, not only overcomes the obstacle of LCE material relaxation hysteresis in establishing stable oscillations but also transforms it into the phase control element required to maintain oscillations, thus achieving self-sustaining oscillations that can operate long-term without external control and relying solely on constant illumination.

[0042] In the self-excited oscillation control system of this embodiment, the dimensionless prestress will be further analyzed. Dimensionless light intensity The elastic modulus of dimensionless elastic fibers (i.e., passive elastic elements b and c) and Dimensionless damping coefficient The influence of six important parameters—thermal relaxation time ratio n, illumination angle range w—on the self-excited oscillation response of vibrating particles is analyzed.

[0043] First, analyze dimensionless prestressing. The influence of dimensionless prestressing. These are key parameters for regulating the dynamic state and oscillation characteristics of a system. For example... Figure 6 As shown, in this embodiment, other parameters are fixed. , , , , , , Under the conditions of prestressing The changes not only determine whether the system can enter a self-excited oscillation state, but also allow for continuous control of the amplitude and frequency of the oscillation.

[0044] When prestress At this point, the system cannot overcome damping dissipation and will remain stationary. The system then enters a state of self-excited vibration, and as... As the number of cycles increases gradually, the oscillation characteristics of the system exhibit a regular evolution. In phase space, the limiting cycles in the x and y directions follow... Enlarged and significantly contracted, such as Figure 6 As shown in (a) and (b), the corresponding planar motion trajectory also gradually evolves from a large closed ellipse to a compact small loop, as... Figure 6 As shown in (c). This phenomenon indicates that the circumference of the trajectory characterizing the amplitude... It decreases monotonically with increasing prestress, such as Figure 6 As shown in (d), the physical mechanism is that the prestress enhances the joint constraint of the three fibers on the mass point, improves the equivalent stiffness of the system, thereby limiting its maximum displacement in all directions and compressing the physical space of the oscillation.

[0045] At the same time, prestress has the opposite effect on the oscillation frequency of the system. For example... Figure 6 As shown in (d), the frequency varies with The prestress increases monotonically. This is because higher prestress causes the fiber to generate a greater elastic restoring force when subjected to the same tensile deformation, thereby accelerating the reciprocating motion of the particles near the equilibrium position and shortening the oscillation period. Therefore, increasing the prestress can obtain high-frequency, small-amplitude compact oscillations, while decreasing the prestress is conducive to generating low-frequency, large-amplitude, relatively gentle motions. Thus, prestress can become a crucial control variable in system design and application.

[0046] Then, the dimensionless light intensity was analyzed. The influence of dimensionless light intensity. It is the energy source that drives the system to generate and maintain self-excited oscillations, and it is also a key external parameter for regulating the oscillation mode. For example... Figure 7 As shown, in this embodiment, other parameters are fixed. , , , , , , Under these conditions, dimensionless light intensity The change in [the system] directly determines whether the system will oscillate and profoundly affects the amplitude and frequency characteristics of its oscillation.

[0047] When dimensionless light intensity When the light intensity is less than 0.04, the energy input for photothermal drive is insufficient to compensate for the inherent damping dissipation of the system, and the system remains stationary. Once the light intensity exceeds this threshold, the system is excited into a stable periodic self-excited oscillation state. As the dimensionless light intensity gradually increases from 0.04, the oscillation behavior of the system changes significantly. In phase space, the limiting cycles in the x and y directions change with... Increase and expand synchronously, such as Figure 7 As shown in (a) and (b), the corresponding planar motion trajectory gradually evolves from a small closed loop to an elliptical trajectory with significantly increased size, as... Figure 7 As shown in (c). This phenomenon indicates that the circumference of the trajectory characterizing the amplitude... It increases monotonically with increasing light intensity, such as Figure 7 As shown in (d), the physical mechanism is that the increase in light intensity directly enhances the photothermal contraction effect of LCE fibers, enabling each driving stage to generate greater contraction strain and driving force, thereby pushing the particles further away from the equilibrium position and significantly expanding their range of motion in the plane.

[0048] However, the effect of light intensity on oscillation frequency shows the opposite regulatory trend. For example... Figure 7 As shown in (d), with As the light intensity increases, the system's oscillation frequency exhibits a monotonically decreasing trend. This is because increased light intensity leads to greater stretching and deformation of the elastic fibers, requiring the overcoming of greater elastic potential energy. During the recovery phase, the time required to release this greater potential energy is longer, ultimately resulting in a monotonically decreasing frequency. Therefore, in practical applications, if the system needs to perform large-range, low-frequency scanning or actuation, higher light intensity drive can be used; if rapid, high-frequency reciprocating motion is desired, the ease and continuity of light intensity control make it an effective way to achieve online adjustment of oscillation performance.

[0049] Secondly, the elastic modulus of the dimensionless elastic fiber is analyzed. and The influence of the elastic modulus of dimensionless elastic fibers. and It is a core material parameter that determines the system's recovery stiffness. To simplify the analysis, this study uses a scaling factor. The stiffness of the two elastic fibers is adjusted simultaneously, that is... And keep other parameters unchanged, such as , Its influence pattern is as follows Figure 8 As shown.

[0050] when When the value is too large (i.e., the elastic fiber stiffness is high), the driving force of the LCE fiber is insufficient to deform the elastic fiber, and the system remains stationary. When the temperature drops below the critical value, the system enters a periodic self-excited oscillation state. With... As increases, the limiting cycles in the x and y directions in phase space contract significantly, and the entire cycle shifts to the right of the equilibrium position, meaning the equilibrium position moves to the right, as shown below. Figure 8 As shown in (a) and (b), the corresponding planar motion trajectories (e.g.) Figure 8 (c) shows the perimeter synchronously. A monotonically decreasing trend, such as Figure 8 As shown in (d), the physical mechanism is that the increase in the stiffness of the elastic fiber enhances the elastic constraint on the mass point, which is equivalent to increasing the overall stiffness of the system, limiting the maximum displacement that can be caused by the photothermal drive of the LCE fiber, thereby compressing the spatial range of oscillation.

[0051] At the same time, an increase in the elasticity coefficient significantly increases the oscillation frequency, such as... Figure 8 As shown in (d), the reason is that increased stiffness leads to enhanced elastic restoring force. When a particle deviates from its equilibrium position, the stronger restoring force enables it to achieve a greater restoring acceleration, thus passing through the equilibrium position more quickly and shortening the time of a single oscillation cycle. Therefore, increasing the stiffness of the elastic fiber can achieve compact oscillations with high frequency and small amplitude, while decreasing the stiffness of the elastic fiber is beneficial for generating low-frequency, large-amplitude oscillations. Therefore, adjusting the stiffness of the elastic fiber is a highly practical design parameter for controlling the dynamic performance of a system.

[0052] Then, we analyze the dimensionless damping coefficient. The effect of the dimensionless damping coefficient. The intensity of viscous dissipation experienced by a system during motion is a key parameter determining whether it can achieve and maintain energy balance. For example... Figure 8 As shown, in this embodiment, other system parameters are fixed, such as... , Under the condition of damping coefficient Increasing the value of has a significant inhibitory effect on self-excited oscillations and regularly alters their dynamic characteristics.

[0053] The essence of damping is energy dissipation. When If the value is greater than 200, the energy lost by the system in each cycle will exceed the energy replenished by the photothermal drive, causing the oscillation to become unsustainable and the system to eventually decay to a static state. Within a range that can sustain self-excited oscillation... Within the scope, its impact is as follows Figure 9 As shown. With As the phase space increases, the limiting cycles in both the x and y directions exhibit a contraction trend, such as... Figure 9 As shown in (a) and (b), the corresponding planar motion trajectories also tighten inward synchronously, as... Figure 9 As shown in (c). Quantitative analysis shows that the circumference of the trajectory... Follow Increasing and monotonically decreasing, such as Figure 9 As shown in (d), the physical mechanism is that stronger damping means that the particle experiences greater resistance during its motion.

[0054] At the same time, the damping coefficient also has a clear regulating effect on the oscillation frequency. For example... Figure 9 As shown in (d), the oscillation frequency of the system varies with The viscous damping force increases and then monotonically decreases. This is because the viscous damping force is always opposite to the direction of the velocity, directly hindering the acceleration and deceleration of the particle, thus prolonging the time required for it to complete one full reciprocating motion, i.e., lengthening the oscillation period. This law has important guiding significance for practical applications. If the system is expected to work in a higher damping environment (such as underwater), the driving light intensity needs to be increased accordingly or the structural parameters optimized to compensate for the additional energy loss; conversely, in a vacuum or low-damping environment, the system can achieve higher frequency and larger amplitude oscillations with less driving energy.

[0055] Next, the influence of the thermal relaxation time ratio n is analyzed. The thermal relaxation time ratio n is a key parameter characterizing the intrinsic photothermal response dynamics of LCE materials, directly determining the phase relationship between light-driven and mechanical motion. For example... Figure 9 As shown, in this embodiment, other system parameters are fixed, such as... , Under certain conditions, parameter n has a profound impact on the stability and dynamic characteristics of self-excited oscillations by adjusting the phase and amplitude of the driving force.

[0056] The parameter n determines the phase relationship between photothermal drive and mechanical motion. Within a specific range of n, the system can maintain self-excited oscillation. Within this range, the influence law is as follows: Figure 10 As shown, with increasing n, the limiting cycles in both the x and y directions in phase space exhibit systematic contraction, as... Figure 10 As shown in (a) and (b), the corresponding planar motion trajectory also converges inward, as... Figure 10 As shown in (c). Quantitative analysis shows that the circumference of the trajectory... Follow Increasing and monotonically decreasing, such as Figure 10 As shown in (d), the underlying mechanism is that an increase in the value of n means that the recovery process of LCE fibers after being removed from light exposure slows down significantly. This weakens the driving force at two key stages: first, in the stage where only the particles need to be pulled back to the illuminated area, the LCE fibers fail to elongate sufficiently due to recovery lag, thus reducing the recovery tension provided; second, at the beginning of the next driving cycle, the fibers have not fully recovered to their initial state, thereby reducing their maximum shrinkage potential. These two effects together limit the maximum displacement that the particles can achieve and compress the oscillation amplitude.

[0057] At the same time, increasing the thermal relaxation time ratio n also has a significant slowing effect on the oscillation frequency, such as... Figure 10 As shown in (d). This is mainly due to the fact that the prolonged recovery process directly slows down the rhythm of the entire motion: after the particles leave the illuminated area, they need to wait longer for the LCE fibers to fully recover and accumulate sufficient elastic restoring force, thus delaying the timing of their reverse acceleration and lengthening the entire oscillation period. Therefore, The increase in the amplitude of the oscillation simultaneously weakens the amplitude and frequency of the oscillation. This principle reveals the intrinsic relationship between the thermodynamic properties of the material itself and the overall performance of the system. It provides a theoretical basis for the design and screening of LCE materials for specific applications: by modifying the thermal relaxation characteristics of LCE through chemical modification, doping, or microstructure control, the output performance of the oscillator can be preset and tuned at the "material level" under the same structure and illumination conditions.

[0058] Finally, this embodiment also analyzes the illumination angle range. The impact. This embodiment defines... The angular range of the illuminated area, physically speaking, is the angular size of one side of a strip of light centered at a fixed π / 6 direction within a plane. That is, the illuminated area is: π / 6 - ~π / 6+ The illumination angle range is a key parameter determining the system's illuminated area, energy input rhythm, and the effectiveness of geometric self-switching. For example... Figure 11 As shown, in this embodiment, other system parameters are fixed, such as... Under these conditions, the change in the illumination angle range directly determines whether the system can enter a self-excited oscillation state and significantly modulates the amplitude and frequency characteristics of the oscillation.

[0059] along with As the rad gradually increases from 0.0011 rad, the self-excited oscillation characteristics of the system exhibit a significant two-stage evolution pattern. In the low illumination angle range... Inside, with As the phase space continues to increase, the limiting cycles in the x and y directions gradually expand, and the overall equilibrium position shifts to the left, i.e., the equilibrium position moves to the left, such as... Figure 11 As shown in (a) and (b), the corresponding planar motion trajectories exhibit synchronous expansion, as... Figure 11 As shown in (c). Circumference of the trajectory. It shows a monotonically increasing trend, such as Figure 11 As shown in (d). The physical mechanism is that slightly increasing the illumination angle range can effectively extend the effective light exposure time within a single cycle of LCE fiber, fully stimulate the photothermal contraction effect, significantly enhance the driving force, drive the particles to generate greater displacement, broaden the range of planar motion, and ultimately manifest as the expansion of the limit ring and the increase in the circumference of the oscillation trajectory.

[0060] When the illumination angle range is further increased to After the interval, the system's oscillation characteristics undergo a reverse evolution. With... As the motion continues to improve, the limiting cycles in the x and y directions contract significantly, the overall equilibrium position shifts continuously to the left, and the corresponding planar motion trajectory shrinks considerably, such as... Figure 11 As shown in (c), the perimeter A significant decreasing trend, such as Figure 11 As shown in (d), the physical mechanism lies in the fact that an excessively large illumination angle range significantly covers the motion range of the particles, making it difficult for the LCE fibers to escape the illuminated area. This restricts the fiber relaxation and recovery process, preventing full deformation recovery and resulting in a significant decrease in the structural elastic recovery force. At this point, the particle motion is constrained near the illumination center, the oscillation amplitude continuously decreases, and the limiting cycle and trajectory circumference contract synchronously. When the illumination angle range exceeds the critical threshold... At that time, the LCE fiber is in the light-covered area throughout the process, and continues to be in a state of contraction, completely losing its ability to deform periodically. The self-excited oscillation of the system completely disappears and eventually tends to be still.

[0061] The range of illumination angles also shows a clear trend in regulating the oscillation frequency. For example... Figure 11 As shown in (d), within the effective self-excited oscillation range, the oscillation frequency continuously increases with the increase of the illumination angle range. The physical mechanism is as follows: the widening of the illumination angle range causes the LCE fiber to undergo photothermal contraction earlier, and the particle motion shifts towards the illumination center, significantly reducing the effective travel distance of the reciprocating motion and shortening the cycle period of a single oscillation, ultimately achieving a continuous increase in the oscillation frequency. When the illumination angle range exceeds a critical value... Afterward, the complete periodic motion mechanism is disrupted, the reciprocating oscillations cannot be maintained, and the system tends to become static.

[0062] S4. Adjust the parameters of the planar tension self-excited oscillation control system according to the target control parameter set to drive the vibrating particles to achieve the preset vibration state.

[0063] This embodiment also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the control method for the planar tension self-excited oscillation control system.

[0064] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0065] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Since the above embodiments are substantially similar to the method embodiments, their descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0066] The above embodiments provide a detailed description of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A planar tension self-excited oscillation control system for an optical drive, comprising a vibrating mass (1) and a mounting frame (2) serving as a mounting carrier, characterized in that, Also includes: At least two passive elastic elements capable of elastic stretching (3); At least one photothermal elastic element (4) that can be stretched and contracted by photothermal drive, one end of the passive elastic element (3) and the photothermal elastic element (4) are both connected to the vibrating mass (1), and the other end is both connected to the mounting frame (2); Illuminated area (5) is formed by irradiation by a light source, covering a portion of the photothermal elastic element (4) in its initial state. The photothermal elastic element (4) is driven to expand and contract by control parameters that include at least the illumination angle range, and cooperates with multiple passive elastic elements (3) to make the vibrating particle (1) continuously self-excited or stationary. Within the effective self-excited oscillation range, as the illumination angle range increases, the oscillation frequency continues to rise, and the oscillation amplitude shows a non-monotonic change law of first increasing and then decreasing. When the illumination angle range exceeds the critical threshold, the self-excited oscillation of the system stops.

2. A control method for a planar tension self-excited oscillation control system for an optical drive, based on the planar tension self-excited oscillation control system for an optical drive as described in claim 1, characterized in that, include: Obtain the light-driven strain equation of a photothermal elastic component under both illuminated and unilluminated conditions when it is under tension; The motion equation of the vibrating particle is established based on the optically driven strain equation of the planar tension self-excited oscillation control system and the photothermal elastic component. Based on the motion equation of the vibrating particles, the target control parameter set of the system's vibrating particles when satisfying the preset vibration state is solved; the target control parameter set includes at least one of the following: dimensionless prestress, dimensionless light intensity, dimensionless elastic coefficient of the passive elastic element, dimensionless damping coefficient, thermal relaxation time ratio, and illumination angle range. Based on the target control parameter set, adjust the parameters of the planar tension self-excited oscillation control system to drive the vibrating particles to achieve the preset vibration state.

3. The control method according to claim 2, characterized in that, The specific steps for obtaining the optical drive strain equation are as follows: To ensure that the photothermal elastic component remains taut under both light and non-light conditions; The photothermal elastic element was irradiated by the illuminated area, and the length of the photothermal elastic element was recorded as a function of illumination over time. Remove the illuminated area and record the non-illuminated curve of the length of the photothermal elastic element over time; The light-driven strain equation of the photothermal elastic element is constructed based on the illumination change curve and the non-illumination change curve.

4. The control method according to claim 2, characterized in that, The equation of motion of the vibrating particle is constructed based on its mass, the instantaneous tension of the passive elastic element, the instantaneous tension of the photothermal elastic element, and the damping coefficient. The instantaneous tension of the photothermal elastic element is calculated based on the product of its instantaneous deformation and the equivalent elastic coefficient. The instantaneous deformation of the photothermal elastic element is obtained by calculating the difference between its instantaneous length and the optical drive balance length. The optical drive balance length is calculated based on its optical drive strain equation and original length. The instantaneous tension of the passive elastic element is calculated based on the product of its instantaneous deformation and elastic coefficient.

5. The control method according to claim 2, characterized in that, When solving for the target control parameter set, the motion equations are dimensionless to obtain dimensionless control equations, and the target control parameter set is obtained by solving the dimensionless control equations.

6. The control method according to claim 2, characterized in that, The preset vibration state includes a static state and a periodic self-excited oscillation state; the periodic self-excited oscillation state is when the vibrating particle reciprocates according to a preset trajectory and velocity.

7. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the control method for the planar tension self-excited oscillation control system as described in any one of claims 2 to 6.

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