A CPG phase oscillator model with slip-stick transition function

Abstract

This invention discloses a CPG phase oscillator model with flapping switching function and its application. The model introduces amplitude bias by constructing an amplitude bias equation; by changing the cosine function in the output equation to the form of adding the amplitude bias and sine functions, a sinusoidal signal output is achieved, thus realizing spatial asymmetric flapping; the amplitude bias is changed by introducing a spatial asymmetric flapping coefficient; by designing the amplitude bias equation in two different forms with or without zero amplitude, different outputs of quantitative angle bias signals and periodic rhythm signals can be achieved, thus realizing two different modes of flapping and gliding; by introducing the amplitude bias equation and the improved output equation into the traditional CPG phase oscillator model, the construction of a CPG phase oscillator model with flapping switching function can be completed. The CPG phase oscillator model constructed in this invention is used for the switching and motion control of gliding and flapping modes of a biomimetic flapping-wing robot. It can realize the spatial asymmetric up and down flapping of the flapping wing structure and quantitative angle offset. Moreover, the amplitude offset is individually controllable, and the switching between flapping and gliding modes is fast and smooth. It has the characteristics of simple calculation, convenient control and strong environmental adaptability.

Description

Technical Field

[0001] This invention relates to motion control of a biomimetic flapping-wing robot, and more specifically, to a CPG phase oscillator model with flapping-wing switching function and its application. Background Technology

[0002] In nature, there exist organisms that propel themselves nimbly through water using pectoral fins, as well as a variety of flapping-wing flying creatures. These organisms possess extraordinary locomotion capabilities in specific environments due to their evolved characteristics. Researchers have developed various biomimetic flapping-wing robots by mimicking the characteristics and locomotion mechanisms of these organisms, and these robots are widely used in scenarios such as water quality monitoring, marine search and rescue, and battlefield reconnaissance. Based on these requirements, biomimetic flapping-wing robots need to have strong mobility and the ability to switch between motion modes, thus placing higher demands on the rapid switching of motion modes. However, existing biomimetic flapping-wing robots are limited by their respective locomotion forms, and can only perform tasks in a single motion state of flapping or gliding, which greatly limits the application scenarios and working capabilities of these robots.

[0003] Research indicates that rhythmic movement is controlled by the Central Pattern Generator (CPG) in the spinal cord of animals. The CPG is a neural network, an oscillating network composed of multiple neurons. Through the interconnection of neurons, it achieves self-excited oscillation, generating periodic signals with stable phase relationships. All CPG units form a CPG neural network through topological connections, thereby controlling many parameters of the organism. Traditional CPG phase oscillator models can only output signals with continuously changing amplitudes to achieve flapping mode, making it difficult to maintain the output signal at a certain bias angle to achieve gliding mode. Therefore, using traditional CPG phase oscillator models to achieve gliding and flapping mode switching in biomimetic flapping-wing robots is very difficult, necessitating the design of a new CPG phase oscillator model. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies and achieve gliding and flapping mode switching in a biomimetic flapping robot, this invention proposes a CPG phase oscillator model with gliding-flapping switching functionality. The method is characterized by: for biomimetic robots, by establishing a CPG phase oscillator model with gliding-flapping switching functionality, generating gliding angle deflection signals or flapping rhythm signals with corresponding characteristics, controlling the corresponding units of the phase oscillator, and thus realizing the switching between gliding and flapping modes of the biomimetic flapping robot.

[0005] To achieve the above objectives, the technical solution adopted in this invention is to change the amplitude bias during flapping and gliding by adding an amplitude bias equation; to realize gliding and flapping modes by setting whether the desired amplitude is 0 or not; to construct a CPG phase oscillator model with gliding-flapping switching function; and to control the corresponding unit of the phase oscillator by outputting an angle deflection signal or a sinusoidal rhythm signal from the CPG controller, thereby realizing the switching between gliding and flapping modes of the biomimetic flapping-wing robot.

[0006] This invention utilizes a CPG phase oscillator with an amplitude bias equation to achieve switching between gliding and flapping modes, based on the following traditional phase oscillator model.

[0007]

[0008] The first equation is the amplitude equation, a i Indicates amplitude, γ i A represents a positive constant that controls the convergence rate of the amplitude. i The first equation represents the desired amplitude; the second equation is the phase equation, φ. i f represents the phase of the i-th unit. i ω represents the natural frequency. ij This represents the coupling weight of the j-th unit to the i-th unit. The third equation represents the desired phase difference; the fourth equation is the output equation, θ. i This represents the output value. Where 'a'... i γ i φ i ω ij A is a state parameter. i f i , The input control parameters are shown. It can be seen that in the above model, the output signal is a rhythmic signal, which cannot achieve the fixed-angle deflection signal required to switch from the flapping state to the gliding state.

[0009] This invention establishes an amplitude bias equation based on the amplitude equation, and its expression is as follows:

[0010]

[0011] Among them, a xi Indicates amplitude bias, b i A represents a positive constant that controls the convergence rate of the amplitude bias. xi This indicates the desired amplitude offset.

[0012] The output equation is expressed as:

[0013] θ i =a xi +a i sin(φi )

[0014] Introducing the spatial asymmetric beat coefficient μ i When the desired amplitude A i When it is not 0, it is defined as the ratio of the desired amplitude bias to the desired amplitude; when A i When it is 0, it is defined as the ratio of the desired amplitude bias to the desired amplitude before (or after) transitioning to the gliding state. Spatial asymmetric flapping coefficient μ i Represented as:

[0015]

[0016] Among them, A i A represents the expected amplitude. imax This represents the expected amplitude of the flapping state before (or after) transitioning to a gliding state.

[0017] The established amplitude bias equation, output equation, and spatial asymmetric beat coefficient μ are then used to... i By incorporating the traditional CPG phase oscillator model, the improved CPG phase oscillator model with slip-switching function is obtained as follows:

[0018]

[0019] When A i When the value is not 0, the phase oscillator passes through μ i By controlling the asymmetric flapping characteristics of the control space, rhythmic signals are output to realize the flapping mode of the biomimetic flapping-wing robot; when A i When the value is 0, it indicates that the flapping wing has no periodic flapping motion, and the phase oscillator passes through μ i By controlling the amplitude offset, a quantitative angle deflection of the flapping wing is achieved, thereby realizing the gliding mode of the biomimetic flapping-wing robot. Through equation calculations, the output of each CPG unit can be changed, thus controlling the flapping wing corresponding to each CPG unit, thereby realizing the switching between the flapping mode and the gliding mode of the biomimetic flapping-wing robot.

[0020] Compared with the prior art, the present invention has the following beneficial technical effects:

[0021] This invention designs a CPG phase oscillator model with a gliding and flapping switching function, realizing the switching between gliding and flapping modes of a biomimetic flapping-wing robot. It features simple calculation, convenient control, rapid response, and strong environmental adaptability.

[0022] 1. Traditional CPG phase oscillator models can only generate cosine signals with output values ​​greater than 0. However, controlling the flapping wing structure of a biomimetic flapping-wing robot requires a sinusoidal signal to control the flapping motion. Therefore, traditional CPG phase oscillators are insufficient for motion control of biomimetic flapping-wing robots. This invention introduces an amplitude bias, altering the output equation, enabling sinusoidal signal output, which facilitates the flapping motion of the wing structure.

[0023] 2. The spatial asymmetric beat coefficient μ is defined. i It has a clear physical meaning, can independently control the bias of the output signal, and keep the output signal at a certain bias angle, which can mimic the gliding mode of flapping-wing robots.

[0024] 3. By establishing an amplitude bias equation to change the magnitude of the amplitude bias, and by changing whether the amplitude is 0 or not, the mode switching between flapping gliding and flapping can be achieved, enabling a rapid and smooth transition between the two different modes. Attached Figure Description

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0026] Figure 1 This is a schematic diagram illustrating the sliding and flapping switching principle of a biomimetic flapping-wing robot.

[0027] Figure 2 This is the output diagram of the traditional CPG phase oscillator model described in this invention.

[0028] Figure 3 This is the signal output diagram of the improved sliding switch described in this invention.

[0029] Figure 4 This is a schematic diagram of the ski-bounce switching function of the manta ray-inspired aircraft described in this invention. Detailed Implementation

[0030] To fully and clearly demonstrate the objectives, technical solutions, and advantages of this invention, the specific embodiments of the CPG phase oscillator model with slip-switching function will be further described in detail below with reference to the accompanying drawings. It should be noted in advance that, for ease of description, the accompanying drawings are only schematic diagrams of some relevant structures of this invention and do not represent all embodiments of this invention.

[0031] like Figure 1 As shown, this invention improves upon the traditional CPG phase oscillator by proposing a CPG phase oscillator model with a slip-switching function. The phase oscillator construction process of this invention specifically includes the following steps:

[0032] 1. The traditional phase oscillator equation is as follows:

[0033]

[0034] The first equation is the amplitude equation, a i Indicates amplitude, γ i A represents a positive constant that controls the convergence rate of the amplitude. i The first equation represents the desired amplitude; the second equation is the phase equation, φ. i f represents the phase of the i-th unit. i ω represents the natural frequency. ij This represents the coupling weight of the j-th unit to the i-th unit. The third equation represents the desired phase difference; the fourth equation is the output equation, θ. i This indicates the output value.

[0035] Set f i =0.4, A i =20, the output of the phase oscillator is as follows Figure 2 As shown, although the frequency and amplitude of the output signal reached the expected values, the output signal is a cosine signal greater than 0, which cannot achieve a sine signal output. Therefore, it is impossible to achieve the flapping motion of the wings. Furthermore, the output signal cannot be maintained at a certain value, so the flapping wings cannot be maintained at a certain deflection angle to achieve gliding motion.

[0036] 2. Following the amplitude equation, establish the amplitude offset equation, whose expression is:

[0037]

[0038] Among them, a xi Indicates amplitude bias, b i A represents a positive constant that controls the convergence rate of the amplitude bias. xi This indicates the desired amplitude offset.

[0039] The output equation is expressed as:

[0040] θ i =a xi +a i sin(φ i )

[0041] 3. Introduce the spatial asymmetric beat coefficient μ i When the desired amplitude A i When it is not 0, it is defined as the ratio of the desired amplitude bias to the desired amplitude; when A i When it is 0, it is defined as the ratio of the desired amplitude bias to the desired amplitude before (or after) transitioning to the gliding state. The spatial asymmetric flapping coefficient is expressed as:

[0042]

[0043] Among them, A i A represents the expected amplitude. imax This represents the expected amplitude of the flapping state before (or after) transitioning to a gliding state.

[0044] 4. The established amplitude bias equation, output equation, and spatial asymmetric beat coefficient μ are then compared. i By incorporating the traditional CPG phase oscillator model, the improved CPG phase oscillator model with slip-switching function is obtained as follows:

[0045]

[0046] Initial variable A i 、T、δ i μ i The values ​​are 20°, 2.5s, 1, and 0.5, respectively. Initially, the output variable θ is a spatially asymmetric rhythmic signal, with a maximum output of 30° and a minimum output of -10°; then at 3s, μ... i From 0.5 to 1.5, A i From 20° to 0°, the output signal changes from a spatially asymmetric rhythmic signal to a quantitative angular deflection signal. After a short settling time, the output variable θ stabilizes at 30°, realizing the switching from flapping mode to gliding mode; then at 8s, μ i When A changes from 1.5 to 0.5, i From 0° to 20°, the output signal changes from a quantitative angle deflection signal back to a spatially asymmetric rhythmic signal, realizing the switching from gliding mode to flapping mode. The output of the phase oscillator is as follows: Figure 3 As shown in the figure. It can be seen that by changing the spatial asymmetry coefficient μ... i and amplitude A i Whether it is 0 or not, the CPG phase oscillator realizes the mutual transformation from spatial asymmetric rhythmic signals to quantitative angle deflection signals, and realizes the rapid and smooth transition of different types of signals and the rapid switching between gliding and flapping modes.

[0047] 5. When A i When the value is not 0, the phase oscillator passes through μ i By controlling the asymmetric flapping characteristics of the control space, rhythmic signals are output to realize the flapping mode of the biomimetic flapping-wing robot; when A i When the value is 0, it indicates that the flapping wing has no periodic flapping motion, and the phase oscillator passes through μ i By controlling the amplitude offset, a quantitative angle deflection of the flapping wing is achieved, thereby realizing the gliding mode of the biomimetic flapping-wing robot. Through equation calculations, the output of each CPG unit can be changed, thus controlling the flapping wing corresponding to each CPG unit, thereby realizing the switching between the flapping mode and the gliding mode of the biomimetic flapping-wing robot.

[0048] 6. The phase oscillator proposed in this invention is applied to the ski-flapping switching control of a manta ray-inspired aircraft, such as... Figure 4 As shown. The manta ray-inspired vehicle has three servos on its left pectoral fin, named servos 1, 2, and 3, and servos on its right pectoral fin, named servos 4, 5, and 6. These six driving servos correspond to the six pectoral fin rays. Each servo is controlled by a phase oscillator model, and the interconnections between the servos are achieved through a CPG topology network and coupling terms. When A... i When A is not zero, the control system can convert the spatially asymmetric signals output by each CPG phase oscillator in the CPG network into biased servo rotation angle control signals, realizing the flapping mode of a manta ray-inspired vehicle; when A i When it is 0, by changing μ i The CPG phase oscillator outputs a quantitative angle deflection signal, and the rotation angle of each servo motor is kept at a constant value without periodic flapping, so that the pectoral fin is kept at a fixed offset angle, realizing the gliding mode of the manta ray mimicry vehicle, thereby realizing the ski-flapping switching function of the manta ray mimicry vehicle.

[0049] The specific embodiments described above are merely for illustrating and explaining the technical concept of the present invention and should not be used to limit the present invention. Any modifications, substitutions, and improvements made to the technical solutions within the design concept and principles of the present invention should be within the protection scope of the present invention.

Claims

1. A CPG phase oscillator model with slip-switching function, characterized in that, The model is expressed as follows: The first equation is the amplitude equation. Indicates amplitude bias. This represents a positive constant that controls the convergence speed of the amplitude bias. Indicates the expected amplitude. For spatial asymmetric beat coefficients: , Indicates the desired amplitude offset. This represents the expected amplitude of the flapping state before or after transitioning to a gliding state; In the second equation, Indicates amplitude. This represents a positive constant that controls the convergence rate of the amplitude. The third equation is the phase equation. Indicates the first i The phase of each unit, Indicates the natural frequency. Indicates the first j The unit for the first i The coupling weights of each unit, Indicates the desired phase difference; The fourth equation is the output equation. Indicates the output value. , , , For state parameters, , , These are the input control parameters; Among them, when When the value is not 0, the phase oscillator passes through By controlling the asymmetric flapping characteristics of the control space, rhythmic signal output is achieved, realizing the flapping mode of the biomimetic flapping-wing robot; when When the value is 0, it indicates that the flapping wing has no periodic flapping motion, and the phase oscillator passes through... By controlling the amplitude offset, a quantitative angle deflection of the flapping wing can be achieved, thereby realizing the gliding mode of the bionic flapping wing robot. Through equation calculation, the output of each CPG unit can be changed, thereby realizing the control of the flapping wing corresponding to each CPG unit, thus realizing the switching between the flapping mode and the gliding mode of the bionic flapping wing robot.

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