CN111796520A - Modeling method and modeling system for soft robot, electronic device, and storage medium - Google Patents
Modeling method and modeling system for soft robot, electronic device, and storage medium Download PDFInfo
- Publication number
- CN111796520A CN111796520A CN202010603763.0A CN202010603763A CN111796520A CN 111796520 A CN111796520 A CN 111796520A CN 202010603763 A CN202010603763 A CN 202010603763A CN 111796520 A CN111796520 A CN 111796520A
- Authority
- CN
- China
- Prior art keywords
- telescopic pipe
- bending
- inflatable
- uninflated
- micro
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B13/00—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion
- G05B13/02—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric
- G05B13/04—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric involving the use of models or simulators
- G05B13/042—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric involving the use of models or simulators in which a parameter or coefficient is automatically adjusted to optimise the performance
Landscapes
- Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Artificial Intelligence (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Evolutionary Computation (AREA)
- Medical Informatics (AREA)
- Software Systems (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Manipulator (AREA)
Abstract
The application discloses a modeling method and a modeling system of a software robot, electronic equipment and a storage medium. The modeling method includes differentiating a simplified model of a flexible driving portion into a plurality of micro-segments; and (3) any micro-segment is selected, a motion model of the micro-segment is established, the motion model of the micro-segment is integrated to obtain a motion model of the soft robot, and a model of inflation pressure and bending deformation of the flexible driving part is established. The modeling method is suitable for the soft robot with large bending deformation, can quickly establish the model of the soft robot, conveniently and accurately control the motion of the soft robot in real time, and improves the working efficiency.
Description
Technical Field
The present invention relates generally to the field of robotics, and more particularly to a modeling method and a modeling system for a soft robot, an electronic device, and a storage medium.
Background
Since the first industrial robot came into the market, the technology and research directions of the robot have been continuously updated for more than half a century. At present, a plurality of new problems are also provided for the development of robots, for example, in special robots in special environments, the fact that the manufactured robots are not completely suitable for practical situations is found. For example, an auxiliary robot and a power-assisted robot, the robot structure is too large, lacks flexibility and has too large rigidity, and obviously has great limitation in application.
Compared with a rigid robot, the soft robot has obvious advantages in the aspects of grabbing flexible objects, operating in narrow space and frequent human-computer interaction. When touching personnel, the soft robot needs to keep smaller rigidity so as to ensure the self-adaptability and the safety of the personnel. When grabbing an operation object, the soft robot needs to keep higher rigidity so as to ensure the grabbing force and the control performance of the soft robot. The kinematics and dynamics modeling of the soft robot is still a problem to be solved internationally at present just because of the characteristics of large flexibility and bending of the soft robot. However, the conventional kinematics model based on the assumption of constant curvature has certain adaptability under small bending deformation, but has no adaptability under large bending deformation.
Disclosure of Invention
In view of the above-mentioned drawbacks and deficiencies of the prior art, it is desirable to provide a modeling method and a modeling system for a soft robot, an electronic device, and a storage medium, which respectively establish a motion trajectory model of a flexible driving portion and a mathematical model between inflation pressure and flexible bending deformation.
In a first aspect, the present invention provides a modeling method for a soft robot, the soft robot includes a flexible driving portion, the flexible driving portion is driven by gas, the flexible driving portion includes at least two pneumatic muscles, each pneumatic muscle includes a telescopic tube and a corrugated mesh grid, the corrugated mesh grid is wrapped on an outer wall of the telescopic tube, and two adjacent pneumatic muscles are connected by a suture line, the modeling method includes:
differentiating the simplified model of the flexible drive into a plurality of micro-segments;
and (3) any micro-segment is selected, a motion model of the micro-segment is established, the motion model of the micro-segment is integrated to obtain a motion model of the soft robot, and a model of inflation pressure and bending deformation of the flexible driving part is established.
In a second aspect, the present invention provides a modeling system for a soft robot, comprising:
a differentiation unit for differentiating the flexible driving part of the soft robot, which is simplified into a curved cylinder in advance, into a plurality of micro-segments;
the establishing unit is used for selecting one micro-segment, establishing a motion model of the micro-segment, integrating the motion model of the micro-segment to obtain a motion model of the soft robot, and establishing a model of the inflation pressure and the bending deformation of the flexible driving part.
In a third aspect, the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the modeling method for a soft robot according to the first aspect.
In a fourth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored, wherein the computer program, when executed by a processor, implements the modeling method for a soft robot according to the first aspect.
When the flexible driving part motion model of the soft robot is established, the invention defines a kinematic model through a differential curve based on the arc length and establishes a dynamic model of a soft joint through an energy conservation principle based on the kinematic model. And the elastic potential energy of the silica gel material is fitted to the change of the elastic potential energy in the deformation process through a Yeoh model in the calculation of the elastic potential energy of the silica gel tube. This method more realistically describes the energy transfer of the soft body arm during bending. The invention can describe the change between the curvature and the bending rate of the motion curve of the soft robot by a Fliner formula. When the motion model is established, the strain energy density of the silica gel material is established by using a Yeoh model, the relation between the inflation pressure and the bending deformation of the soft robot is established by using the energy conservation principle and a Hagen-Poiseuille formula, the model of the soft robot can be quickly established, the motion of the soft robot can be conveniently and accurately controlled, and the working efficiency is improved.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:
FIG. 1 is a schematic diagram of a soft robot suitable for use in the present invention;
FIG. 2 is a schematic diagram of the structure of the pneumatic muscle of FIG. 1;
FIG. 3 is a schematic flow chart of a modeling method of a soft robot according to an embodiment of the present invention;
FIG. 4 is a graph of the relationship between pneumatic muscle and bending length in an embodiment of the invention;
FIG. 5 is a graph of pneumatic muscle versus tip bend angle;
FIG. 6 is a schematic diagram of a modeling system of a soft-bodied robot according to another embodiment of the present invention;
FIG. 7 is a block diagram of an electronic device or computer system 600 suitable for implementing embodiments of the present application.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
The application provides a modeling method of a soft robot. Can be applied to a soft robot, such as the structure similar to that shown in figures 1-2.
Example (c):
a soft robot comprises a flexible driving part, wherein the driving mode of the driving part is fluid driving, and the driving part bends or extends under the driving of the fluid to move and take a target object. Due to the existence of the flexible driving part, the soft robot of the embodiment can not only realize bending motion like the traditional rigid body robot, but also realize flexible motion, and the grabbing behavior is compared with a rigid tentacle, and the soft robot does not have rigid collision. Therefore, the object to be grabbed cannot be damaged, and the object with a complex and fragile surface can be effectively grabbed. The soft driving part has the characteristic of large bending deformation, so the soft driving part has wide application in other scenes. For example, search and rescue operations are performed in a complex environment.
Fluid actuation refers to actuation by using newtonian fluids, for example: air and other various non-toxic and harmless gases, water and other most pure liquids, light oil and low molecular compound solutions. Fluid actuation utilizes the principle that a flexible drive section can deform under applied pressure from fluid (gas or liquid) actuation, allowing for different lengths of elongation or different angles of bending motion. Thereby realizing the grabbing or moving of the target object.
Specifically, two ends of the flexible driving part are respectively connected with an air inlet end cover 2 and a closed end cover 5, and an air inlet 1 is formed in the air inlet end cover 2. The air inlet hole 1 is used for communicating with outside air and controlling the driving part to bend or extend.
Further, the flexible driving portion is at least two pneumatic muscles 3, each pneumatic muscle 3 comprises a telescopic pipe 4 and a corrugated woven mesh 6, the corrugated woven mesh 6 is wrapped on the outer wall of the telescopic pipe 4, and the two adjacent pneumatic muscles 3 are connected through a suture line.
The corrugated woven mesh 6 comprises a corrugated structure formed by carbon fibers stacked along the axial direction of the telescopic pipe 4, the length of the corrugated woven mesh 6 along the axial direction of the telescopic pipe 4 is greater than that of the telescopic pipe 4 along the axial direction of the telescopic pipe, so that the telescopic pipe can be wrapped by the corrugated woven mesh 6 after being axially extended along the axial direction of the telescopic pipe, and the length of the corrugated woven mesh 6 along the axial direction of the telescopic pipe 4 is equal to the maximum length of the telescopic pipe 4 along the axial direction of the telescopic pipe.
Preferably, the telescopic tube 4 is made of flexible material, such as silicone tube.
The extension amount of the carbon fiber reinforced corrugated woven mesh is derived from an axially laminated corrugated structure, the structure of the corrugated mesh ensures that the extension amount of pneumatic muscles is independent of the weaving angle of the fibers, and the design limitation of pneumatic muscles and bag particle type pneumatic muscles based on the traditional double-spiral woven mesh is broken through. The telescopic pipe is hollow and communicated with the air pipe to drive the flexible assembly to bend or extend.
Furthermore, the flexible driving part adopts three pneumatic muscles 3, the three pneumatic muscles 3 are arranged in an equilateral triangle, the air inlet end cover 2 and the closed end cover 5 are respectively provided with three connectors 8, the three connectors 8 are respectively provided with air holes, and the air holes can be respectively and independently communicated with an air pipe to fill air into each telescopic pipe 4.
The air inlet can be ventilated independently and controlled independently, so that the soft robot has three independently controllable control air passages, and can realize three movements. When air pressure is filled into one control air passage in the soft robot, the air passage extends, and the rest two air passages do not extend when the air pressure is not filled. Due to the limiting effect of the braided wire, the elongation motion of the inflatable air passage is influenced, so that the three-channel pneumatic soft robot generates bending motion; when three air passages of the soft robot are filled with different air pressures, the extension lengths in the three air passages are different, and the three-cavity pneumatic soft robot can realize twisting extension movement in a three-dimensional space due to the limitation of braided wires; when the three air passages are simultaneously filled with the same air pressure, the three pneumatic muscles have the same elongation, and the whole soft robot generates axial elongation motion under the limiting action of the braided wire. The three movements are increased along with the increase of the inflation pressure, the bending angle, the torsion length and the elongation. When the air pressure in the control air passage is released, the soft robot recovers the initial state due to the elastic action of the silica gel pipe fitting.
The traditional kinematics model based on the fixed curvature assumption has certain adaptability under small bending deformation, but does not have adaptability under large bending deformation. The present application provides a modeling method of a soft robot, as shown in fig. 3, specifically including:
s100, differentiating the simplified model of the flexible driving part into a plurality of micro-segments;
s200, any micro-segment is selected, a motion model of the micro-segment is established, the motion model of the micro-segment is integrated to obtain a motion model of the soft robot, and a model of inflation pressure and bending deformation of the flexible driving part is established.
In S100, the differentiation of the soft robot into a curved cylindrical shape can be understood as follows: since the soft robot adopts the flexible driving part, the reduction of the soft robot into the curved cylindrical shape herein means the reduction of the driving part into the curved cylindrical shape. The simplification to the curved cylinder shape is beneficial to better describe the kinematic model of the soft robot. Because the bending degrees of the soft robot are different, the simplified soft robot is differentiated, so that the motion state of the soft robot can be accurately described.
In S200, any micro segment is selected, and a motion model of the micro segment is established. In the embodiment, the motion model of the micro-segment is established by using a Fliner formula, namely the motion track of the flexible driving part is established. The flener's formula is capable of describing the motion of particles in space on a continuous differentiable curve. More specifically, the flener's formula describes the relationship between tangent, normal, and secondary normal of the curve. The tangent vector field of each bending curve in the flexible driving part, the curvature of the bending curve and the main normal vector are calculated through a Flerner formula to express the motion trail of the bending curve, and the change rule of the curvature and the curvature of the space curve is described.
And S200, establishing a mathematical model of the inflation pressure and the bending deformation of the flexible driving part according to the energy conservation principle and the tail end force balance principle. The dynamic model of the soft robot is established through the steps. A mathematical model of inflation pressure and bending deformation of the flexible driving part is established, the dynamic process of the soft robot is analyzed, and the soft robot is favorably and accurately controlled to work.
As a realizable way, S200, a process of building a motion model of the micro-segment. The method specifically comprises the following steps:
s201, calculating a tangent vector of each bending curve in the micro-segment;
s202, respectively calculating the curvature and the principal normal vector of each corresponding bending curve according to the tangent vector;
s203, calculating a second normal vector of each corresponding bending curve according to the tangent vector and the main normal vector;
s204, calculating the bending rate of the bending curve according to the second normal vector of the bending curve and the main normal vector of the bending curve;
s205, determining the motion track of the differential section according to the curvature of the bending curve, the main normal vector of the bending curve and the second normal vector of the bending curve.
It should be noted that the curvature of the curved line can be used to describe the curvature of the curve equation at a certain point, and therefore, the curvature of the curved line can be understood as the derivative of the unit vector of the tangent vector. The second normal vector of the curved line is a vector perpendicular to the tangent vector and the principal normal vector of the curved line, and thus can be determined by cross-multiplication of the tangent vector and the principal normal vector of the curved line. The bending rate of the bending curve reflects the rotation speed of the tangent plane of the curve. In the working process of the soft robot, the curvature of the bending curve, the main normal vector of the bending curve and the second normal vector of the bending curve continuously change along with the bending of the flexible driving part, so that the flexible driving part can be used for reflecting the motion track of the flexible driving part of the soft robot.
As a realizable mode, S200, a model of inflation pressure and bending deformation of the flexible driving part is established. The specific process is as follows:
s301, obtaining material parameters of the telescopic pipe, wherein the material parameters comprise the original wall thickness of the telescopic pipe when the telescopic pipe is not inflated, the original length of the telescopic pipe when the telescopic pipe is not inflated, the original radius of the telescopic pipe when the telescopic pipe is not inflated, the wall thickness of the inflatable telescopic pipe, the bending length of the inflatable telescopic pipe, the wall thickness of the uninflated telescopic pipe when pneumatic muscles are inflated, the bending length of the uninflated telescopic pipe when the pneumatic muscles are inflated and the radius of the inflatable telescopic pipe;
s302, respectively fitting by utilizing a Yeoh model according to material parameters to obtain the strain energy density of an inflatable telescopic pipe during inflation, the strain energy density of an uninflated telescopic pipe and the volume variation of the inflatable telescopic pipe;
s303, calculating the deformation work of the inflatable telescopic pipe during inflation according to the strain energy density of the inflatable telescopic pipe and the volume change of the inflatable telescopic pipe, and calculating the deformation work of the uninflated telescopic pipe during inflation according to the strain energy density of the uninflated telescopic pipe and the deformation of the uninflated telescopic pipe;
s304, calculating the working of the inflating air pressure according to the deformation work of the inflating telescopic pipe during inflation and the deformation work of the non-inflating telescopic pipe during inflation by using an energy conservation principle;
s305, determining a model of the tail end air pressure and the bending deformation of the flexible driving part according to a Hagen-Poiseuille formula and the inflating air pressure acting.
It should be noted that:
the telescopic tube in the pneumatic muscle is cylindrical under the unstretched state, and becomes flat and barrel-shaped after being inflated and stressed. Thus, the bellows can be considered as a spring system, the spring force being provided by the strain energy density of the bellows. Therefore, the deformation work of the inflatable telescopic pipe in the pneumatic muscle during inflation is obtained through calculation of the strain energy density of the inflatable telescopic pipe in the pneumatic muscle and the volume variation of the inflatable telescopic pipe, and the deformation work of the uninflated telescopic pipe in the pneumatic muscle is obtained through calculation according to the strain energy density of the uninflated telescopic pipe in the pneumatic muscle and the deformation quantity of the uninflated telescopic pipe in the pneumatic muscle.
As an implementation manner, the step S302 of respectively fitting the strain energy density of the inflatable telescopic tube in the pneumatic muscle, the strain energy density of the uninflated telescopic tube in the pneumatic muscle, and the volume variation of the inflatable telescopic tube by using the Yeoh model according to the material parameters includes:
determining the stretching ratios of the inflatable telescopic pipe in three directions during inflation, wherein the three directions are the bending direction of the telescopic pipe, the radial direction of the telescopic pipe and the circumferential direction of the telescopic pipe respectively;
and determining the stretching ratio of the uninflated telescopic pipe in three directions when the telescopic pipe is inflated.
It should be noted that:
the three directions are respectively the bending direction of the telescopic tube, the radial direction of the telescopic tube and the circumferential direction of the telescopic tube, and it is understood that the three directions should respectively correspond to the curvature changing direction, the second main normal vector and the curvature changing direction in fitting the flexible driving portion into the curved cylindrical shape.
The embodiment discloses a soft robot kinematics and dynamics modeling method which is suitable for a soft robot with large bending deformation. The change between the curvature and the bending rate of the motion curve of the soft robot is described by a Fliner formula. When the model is established, the strain energy density of the silica gel material is established by using a Yeoh model, and the relationship between the inflation pressure and the bending deformation of the soft robot is established by using a Hagen-Poiseuille formula and an energy conservation principle.
Illustratively, the specific process of the modeling method of the soft robot of the application is as follows:
simplifying the three-channel flexible robot into a curved cylinder, differentiating the curved cylinder, taking any micro-segment, setting a bottom circle OA as a fixed base and a top circle OB as a movable end, and establishing two Cartesian coordinate systems respectively with circle centers A and B, namely A (x, y, z) and B (u, v, e). Each bend line in the bending cylinder has a corresponding AiBiAnd (4) showing. By d(s)
The tangent vector of (a), s is the arc length, can be obtained by:
d(s)＝(bi-ai)+H (1)
wherein the content of the first and second substances,
is the position vector of the mass center, h is the central height of the differential section base and the movable end cover,
is a vector of the position of the object,
the position vector of (2). Unitizing the d(s) vector as α(s):
the corresponding curvature κ of the curved curve is used to describe the curvature of the curve equation at s, and the absolute value of the derivative of the tangent vector α(s) to the arc length may be used
To measure:
wherein, Delta theta is a unit tangent vector alpha (s + Delta s) and is translated to the moving origin AiThe angle formed with alpha(s). Vector quantity
Perpendicular to α(s), this direction vector is unitized and denoted as β(s), and is generally called the principal normal vector mathematically, and can be used
To be expressed as follows:
determining a second normal vector γ(s) of the curve from the tangent vector α(s) and the main normal vector β(s) of the curve:
the curvature τ of the curve reflects the rotation speed of the osculating plane of the curve, as shown in formula (6):
the motion trail equation of the soft robot is represented by parameterization of the arc length s, the motion trail equation defined by the arc length parameter is recorded as r(s), and the change rule of the curvature and the flexibility of the space curve can be described by a Fliner formula:
solving the 3 first-order ordinary differential equations by numerical integration, combining initial conditions to obtain a numerical solution of a tangent vector alpha(s) at each point s, and substituting the numerical solution into the tangent vector alpha(s)
The motion trail equation of the soft robot can be obtained.
The kinematic model of the variable stiffness soft driving module can be described by a Fliner formula.
In the aspect of pneumatic modeling of the three-channel soft tentacle, a silica gel material strain energy density calculation formula is fitted by using a Yeoh model, wherein the strain energy density changes as follows:
W1＝C10(I11-3)+C20(I11-3)2(8)
wherein: w1The elastic strain energy density of the inflatable silicone tube; c10，C20Is a silica gel material parameter; i is11Is the first invariant of Cauchy strain, referred to as the three principal directions tensile ratio λ11、λ12、λ13Determination of where11In the axial direction of the pneumatic muscle, λ12In the circumferential direction of the pneumatic muscle, lambda13In the radial direction of the pneumatic muscle. The three principal direction stretch ratios can be represented by equation (9):
the axial extension of silicone tube, the wall thickness attenuation, circumferential direction because the restriction of ripple braided wire, its deformation can be ignored. Incompressible Condition lambda in combination with silica gel Material11λ12λ131, the draw ratio λ of the three main directions11、λ12、λ13Comprises the following steps:
L1is the initial length of the silica gel tube, L'1Is the inflated bending length r of the inflated silicone tube1Is the initial inner diameter of the silicone tube, r'1The inner diameter of the silicone tube after inflation is obtained by integrating the formula (9) and the formula (10):
similarly, the elastic strain energy density W of the uninflated silicone tube2The three main direction stretch ratios of (a) can be obtained from the following equation:
wherein L is2Is the initial length of the uninflated silicone tube, L2＝L1。L′2Is the length of the uninflated silicone tube after being passively bent and deformed under the driving of the silicone tube. I is21Is the first strain invariant of the uninflated silicone tube, from lambda21、λ22、λ23Determination of where21、λ22、λ23The stretching ratio of three main directions of the uninflated muscle in the stretching deformation process. The strain of the uninflated silicone tube is the first invariable as follows:
the energy conservation equation for a flexible drive can be derived as follows:
WP＝W11+2W22(14)
wherein WpWork done by inflation pressure, W11Is the total strain energy of the gas-filled silicone tube, W22Is the total strain energy of the uninflated silicone tube during passive bending deformation.
The strain energy density of the silica gel pipe fitting is obtained by integrating the following steps:
the total strain energy of the gas silicone tube can be given by the following formula:
W11＝W1V1＝W1[π(2r1t1+t1 2)L1](17)
wherein V1Is the volume of the silicone tube, t1The silicone tube is cylindrical in an unstretched state for the initial thickness of the inflatable silicone tube, and the length of the silicone tube is increased after the silicone tube is stressed and is still kept cylindrical. The silicone tube can be considered as a spring system, with the spring force being provided by the strain energy density of the silicone material. Similarly, the total strain energy of the silicone tube of the uninflated muscle can be obtained by the following formula:
W22＝W2V2＝W2[π(2r2t2+t2 2)L2](18)
wherein r is2＝r1Is the inner diameter, t, of an uninflated silicone tube2Is the initial thickness of the uninflated silicone tube.
The pneumatic work done at the tail end of the inflatable pipe fitting can be obtained by the following formula:
Wp＝(P2(s)-Pa)π[(r1′)2L′1-r1 2L](19)
wherein P is2(s) is the internal pressure of the silicone tube, PaIs atmospheric pressure under standard condition，r1' is the inner diameter of the air-filled silicone tube after bending deformation. The relationship between the terminal air pressure and the bending deformation of the flexible joint can be obtained by integrating the formula as follows:
considering laminar flow between the flow control valve and the pneumatic muscle, the Hagen-Poiseuille equation is used:
wherein P is1(S) is the input pressure to the flow control valve,. mu.is the gas dynamic viscosity,. v (S) is the volumetric flow, and S ═ π r1 2Is the cross section of the inner cavity.
By substituting equations (16) - (20) into (14), the relationship between the input air pressure of the flow control valve and the bending deformation of the flexible joint can be obtained by integrating the above equations as follows:
wherein λ ═ L'1/L1，ξ＝L′2/L2The axial Cauchy strain of the inflated muscle and the uninflated muscle respectively can be obtained by the motion trail equation in the kinematic model through integration.
According to the invention, the large deformation factor of the silicone tube after inflation is considered, and the internal pressure difference of the silicone tube is continuously changed. According to a certain instantaneous state determined by the change of the inner radius and the change of the wall thickness of the silicone tube, a Hagen-Poiseuill described pressure and deformation model is established to form a nonlinear mathematical model of the whole operation process of the driver. Since the silicone material is a nonlinear material, the silicone tube is assumed to be a linear spring before the pneumatic muscle deformation model is established. The assumption is obvious that errors exist, and the Yeoh model is introduced to fit the strain energy density generated by deformation of the silicone tube, so that the accuracy of the nonlinear strain increasing model of the deformation of the silicone tube can be well fitted. The invention provides a relatively accurate analysis model aiming at the motion and the stress bending large deformation of a highly nonlinear soft robot, has both precision and rapidity, and can be used for a real-time control experiment of the soft robot. If the finite element method is adopted for modeling, although more detailed parameter values such as movement, pressure and the like can be obtained, a large amount of computing resources and computing time are consumed, and therefore the method cannot be used for real-time control of the software robot.
In order to verify the reliability of the kinematics and pneumatic model, the soft driving part is fixed on the aluminum alloy beam through a clamp, and the flexible driving part is provided with three stay wire type encoders for measuring the bending length of three pneumatic muscles. An MPU6050 sensor is mounted at the end of the soft drive for measuring the bending angle of the pneumatic muscle end. The three pull-wire sensors and MPU6050 data are transmitted to the industrial computer through the STM32 controller. The data for the flexible drive is shown in table 1 below:
TABLE 1 Flexible Joint parameter Table
Air pressure is introduced into any one of the control air passages of the soft driving part, the flexible driving part is bent and deformed, the pull-wire type sensor measures the bending length of the flexible joint, and the MPU6050 measures the bending angle of the tail end of the flexible joint. The data of the two sensors are transmitted to an upper computer through STM32, and the industrial personal computer records the data obtained by the two sensors under different air pressures. And (3) repeatedly carrying out a plurality of experiments, recording the data of the air pressure and the tail end angle and the deformation elongation of the flexible bending joint, and drawing a relation graph of the air pressure and the bending length of the flexible driver as shown in fig. 4, wherein fig. 5 is a relation graph of the air pressure and the tail end bending angle of the flexible driver. From the results in the figure, the theoretical numerical values and the simulation results are very close, which shows that the method of the invention can accurately obtain the model of the flexible driving part.
Another embodiment of the present invention provides a modeling system of a soft robot, as shown in fig. 6, including the following:
a differentiation unit 100 for differentiating the flexible driving part of the soft robot, which is previously simplified into a curved cylinder, into a plurality of micro-segments;
the establishing unit 200 is used for selecting any micro-segment, establishing a motion model of the micro-segment, integrating the motion model of the micro-segment to obtain a motion model of the soft robot, and establishing a model of the inflation pressure and the bending deformation of the flexible driving part.
The system of this embodiment may be configured to implement the technical solutions of the above-described method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
As an implementation manner, the building unit 200, which executes a process for building a motion model of micro-segment, further includes:
a first calculating module 201, configured to calculate a tangent vector of each curve in the segment;
the second calculating module 202 is configured to calculate a curvature of the curved line and a principal normal vector of the curved line according to the tangent vector;
a third calculating module 203, configured to determine a second normal vector of the bending curve according to a tangent vector of the bending curve and a principal normal vector of the bending curve;
a fourth calculating module 204, configured to calculate a bending rate of the bending curve according to the second normal vector of the bending curve and the main normal vector of the bending curve;
the first determining module 205 is configured to determine a motion trajectory of the micro-segment according to the curvature of the curved line, a main normal vector of the curved line, and a second normal vector of the curved line.
The system of this embodiment may be configured to implement the technical solutions of the above-described method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
As an implementation manner, the establishing unit 200, executing a model for establishing the inflation pressure and the bending deformation of the flexible driving portion, further includes:
the acquisition module 301 is used for acquiring material parameters of the telescopic pipe, wherein the material parameters comprise the original wall thickness of the telescopic pipe when the telescopic pipe is not inflated, the original length of the telescopic pipe when the telescopic pipe is not inflated, the original radius of the telescopic pipe when the telescopic pipe is not inflated, the wall thickness of the inflatable telescopic pipe, the bending length of the inflatable telescopic pipe, the wall thickness of the uninflated telescopic pipe when pneumatic muscles are inflated, the bending length of the uninflated telescopic pipe when the pneumatic muscles are inflated and the radius of the inflatable telescopic pipe;
the fitting module 302 is used for respectively fitting by utilizing a Yeoh model according to the material parameters to obtain the strain energy density of the inflatable telescopic pipe during inflation, the strain energy density of the uninflated telescopic pipe and the volume variation of the inflatable telescopic pipe;
a fifth calculating module 303, configured to calculate the deformation work of the inflatable telescopic tube during inflation according to the strain energy density of the inflatable telescopic tube and the volume variation of the inflatable telescopic tube, and calculate the deformation work of the uninflated telescopic tube during inflation according to the strain energy density of the uninflated telescopic tube and the deformation of the uninflated telescopic tube;
a sixth calculation module 304, configured to calculate the work done by the inflation air pressure according to the deformation work of the inflation extension tube during inflation and the deformation work of the non-inflation extension tube during inflation by using the energy conservation principle;
and a second determining module 305, configured to determine a model of the terminal air pressure and the bending deformation of the flexible driving portion according to the terminal force balance principle and the inflation air pressure.
The system of this embodiment may be configured to implement the technical solutions of the above-described method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
As an implementation manner, the performing, by the fitting module 302, a process for respectively fitting the strain energy density of the inflated telescopic tube and the strain energy density of the uninflated telescopic tube during inflation by using a Yeoh model according to the material parameters further includes:
the third determining module is used for determining the stretching ratios of the inflatable telescopic pipe in three directions during inflation, wherein the three directions are the bending direction of the telescopic pipe, the radial direction of the telescopic pipe and the circumferential direction of the telescopic pipe respectively;
and the fourth determination module is used for determining the stretching ratios of the uninflated telescopic pipe in three directions during inflation.
Referring now to FIG. 7, FIG. 7 illustrates a schematic diagram of an electronic device or computer system 600 suitable for use in implementing embodiments of the present application.
As shown in fig. 7, the computer system 600 includes a Central Processing Unit (CPU)601 that can perform various appropriate actions and processes according to a program stored in a Read Only Memory (ROM)602 or a program loaded from a storage section 608 into a Random Access Memory (RAM) 603. In the RAM 603, various programs and data necessary for the operation of the system 600 are also stored. The CPU 601, ROM 602, and RAM 603 are connected to each other via a bus 604. An input/output (I/O) interface 605 is also connected to bus 604.
The following components are connected to the I/O interface 605: an input portion 606 including a keyboard, a mouse, and the like; an output portion 607 including a display such as a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), and the like, and a speaker; a storage section 608 including a hard disk and the like; and a communication section 609 including a network interface card such as a LAN card, a modem, or the like. The communication section 609 performs communication processing via a network such as the internet. The driver 610 is also connected to the I/O interface 605 as needed. A removable medium 611 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is mounted on the drive 610 as necessary, so that a computer program read out therefrom is mounted in the storage section 608 as necessary.
In particular, the process described above with reference to fig. 3 may be implemented as a computer software program, according to an embodiment of the present disclosure. For example, embodiments of the present disclosure include a computer program product comprising a computer program carried on a machine-readable medium, the computer program containing program code for performing the method of fig. 3. In such an embodiment, the computer program may be downloaded and installed from a network through the communication section 609, and/or installed from the removable medium 611. The above-described functions defined in the system of the present application are executed by the Central Processing Unit (CPU)601 in the computer program.
The units or modules described in the embodiments of the present application may be implemented by software or hardware. The described units or modules may also be provided in a processor, and may be described as: a processor includes a differentiation unit and a building unit. The names of the units or modules do not limit the units or modules in some cases, for example, the establishing unit can also be described as "establishing the motion track of the flexible driving part according to the differential result of the flexible driving part of the flexible cylindrical soft robot obtained by the differential unit".
As another aspect, the present application also provides a computer-readable storage medium, which may be the computer-readable storage medium included in the foregoing device in the foregoing embodiment; or it may be a separate computer readable storage medium not incorporated into the device. The computer readable storage medium stores one or more programs for use by one or more processors in performing the software robot modeling described herein.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (10)
1. The modeling method of the soft robot is characterized by comprising a flexible driving part, wherein the flexible driving part is driven by gas, the flexible driving part comprises at least three pneumatic muscles, each pneumatic muscle comprises a telescopic pipe and a corrugated woven net, the corrugated woven net wraps the outer wall of the telescopic pipe, and two adjacent pneumatic muscles are connected through a suture line, and the modeling method comprises the following steps:
differentiating the simplified model of the flexible drive into a plurality of micro-segments;
and (3) any one micro-segment is selected, a motion model of the micro-segment is established, the motion model of the micro-segment is integrated to obtain a motion model of the soft robot, and a model of inflation pressure and bending deformation of the flexible driving part is established.
2. The method of claim 1, wherein the process of modeling the motion of the micro-segment comprises:
calculating a tangent vector of each bending curve in the micro-segment;
respectively calculating the curvature and a principal normal vector of each corresponding bending curve according to the tangent vector;
calculating a second normal vector of each corresponding bending curve according to the tangent vector and the main normal vector;
calculating the bending rate of each corresponding bending curve according to the second normal vector and the main normal vector;
and determining a motion model of the micro-segment according to the curvature, the main normal vector and the second normal vector.
3. The method of claim 1, wherein said modeling inflation pressure and bending deformation of said flexible drive portion comprises:
acquiring material parameters of the telescopic pipe, wherein the material parameters comprise the original wall thickness of the telescopic pipe when the telescopic pipe is not inflated, the original length of the telescopic pipe when the telescopic pipe is not inflated, the original radius of the telescopic pipe when the telescopic pipe is not inflated, the wall thickness of an inflated telescopic pipe, the bending length of the inflated telescopic pipe, the wall thickness of the uninflated telescopic pipe when the pneumatic muscles are inflated, the bending length of the uninflated telescopic pipe when the pneumatic muscles are inflated and the radius of the inflated telescopic pipe;
respectively fitting by utilizing a Yeoh model according to the material parameters to obtain the strain energy density of the inflatable telescopic pipe during inflation, the strain energy density of the uninflated telescopic pipe and the volume variation of the inflatable telescopic pipe;
calculating the deformation work of the inflatable telescopic pipe during inflation according to the strain energy density of the inflatable telescopic pipe and the volume change of the inflatable telescopic pipe, and calculating the deformation work of the uninflated telescopic pipe during inflation according to the strain energy density of the uninflated telescopic pipe and the deformation of the uninflated telescopic pipe;
calculating the working of the inflation air pressure according to the deformation work of the inflation extension pipe during inflation and the deformation work of the non-inflation extension pipe during inflation by an energy conservation principle;
and determining a model of the tail end air pressure and the bending deformation of the flexible driving part according to the work done by the inflation air pressure.
4. The method of claim 1, wherein the process of obtaining the strain energy density of the inflatable bellows in the pneumatic muscle and the strain energy density of the uninflated bellows in the pneumatic muscle and the change in volume of the inflatable bellows by respectively fitting the strain energy density of the inflatable bellows in the pneumatic muscle and the change in volume of the inflatable bellows according to the material parameters by using a Yeoh model further comprises:
determining the stretching ratios of the inflatable telescopic pipe in three directions during inflation, wherein the three directions are the bending direction of the telescopic pipe, the radial direction of the telescopic pipe and the circumferential direction of the telescopic pipe respectively;
and determining the stretching ratio of the uninflated telescopic pipe in three directions when the telescopic pipe is inflated.
5. A system for modeling kinematics and dynamics of a soft body robot, comprising:
a differentiation unit for differentiating the flexible driving part of the soft robot, which is simplified into a curved cylinder in advance, into a plurality of micro-segments;
and the establishing unit is used for selecting one micro-segment, establishing a motion model of the micro-segment, integrating the motion model of the micro-segment to obtain the motion model of the soft robot, and establishing a model of the inflation pressure and the bending deformation of the flexible driving part.
6. The system of claim 5, wherein the building unit performs a process of motion modeling of the micro-segment, further comprising:
the first calculation module is used for calculating the tangent vector of each bending curve in the micro-segment;
the second calculation module is used for calculating the curvature and the principal normal vector of each corresponding bending curve according to the tangent vector;
the third calculation module is used for calculating a second normal vector of each corresponding bending curve by the tangent vector and the main normal vector;
the fourth calculation module is used for calculating the bending rate of each corresponding bending curve by the second normal vector and the main normal vector;
a first determining module, configured to determine a motion trajectory of the micro-segment according to the curvature, the main normal vector, and the second normal vector.
7. The system of claim 5, wherein the establishing unit performs a process for establishing a model of inflation pressure and bending deformation of the flexible driving portion, further comprising:
the acquisition module is used for acquiring material parameters of the telescopic pipe, wherein the material parameters comprise the original wall thickness of the telescopic pipe when the telescopic pipe is not inflated, the original length of the telescopic pipe when the telescopic pipe is not inflated, the original radius of the telescopic pipe when the telescopic pipe is not inflated, the wall thickness of the inflatable telescopic pipe, the bending length of the inflatable telescopic pipe, the wall thickness of the uninflated telescopic pipe when the pneumatic muscles are inflated, the bending length of the uninflated telescopic pipe when the pneumatic muscles are inflated and the radius of the inflatable telescopic pipe;
the fitting module is used for respectively fitting by utilizing a Yeoh model according to the material parameters to obtain the strain energy density of the inflatable telescopic pipe during inflation, the strain energy density of the uninflated telescopic pipe and the volume variation of the inflatable telescopic pipe;
the fifth calculation module is used for calculating the deformation work of the inflatable extension tube during inflation according to the strain energy density of the inflatable extension tube and the volume change of the inflatable extension tube, and calculating the deformation work of the uninflated extension tube during inflation according to the strain energy density of the uninflated extension tube and the deformation of the uninflated extension tube;
the sixth calculation module is used for calculating the work done by the inflating air pressure according to the deformation work of the inflating extension tube during inflation and the deformation work of the non-inflating extension tube during inflation by an energy conservation principle;
and the second determination module is used for determining a mathematical model of the tail end air pressure and the bending deformation of the flexible driving part according to a tail end force balance principle and the inflating air pressure acting.
8. The system of claim 5, wherein the fitting module performs a process for separately fitting from the material parameters a strain energy density of the inflated bellows and a strain energy density of the uninflated bellows when inflated using a Yeoh model, further comprising:
the third determining module is used for determining the stretching ratios of the inflatable telescopic pipe in three directions during inflation, wherein the three directions are the bending direction of the telescopic pipe, the radial direction of the telescopic pipe and the circumferential direction of the telescopic pipe respectively;
and the fourth determination module is used for determining the stretching ratios of the uninflated telescopic pipe in three directions during inflation.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method according to any of claims 1-4 when executing the program.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method according to any one of claims 1-4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010603763.0A CN111796520A (en) | 2020-06-29 | 2020-06-29 | Modeling method and modeling system for soft robot, electronic device, and storage medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010603763.0A CN111796520A (en) | 2020-06-29 | 2020-06-29 | Modeling method and modeling system for soft robot, electronic device, and storage medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111796520A true CN111796520A (en) | 2020-10-20 |
Family
ID=72803935
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010603763.0A Pending CN111796520A (en) | 2020-06-29 | 2020-06-29 | Modeling method and modeling system for soft robot, electronic device, and storage medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111796520A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114670214A (en) * | 2022-02-24 | 2022-06-28 | 南京理工大学 | Pneumatic soft robot with self-sensing function |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109048980A (en) * | 2018-09-14 | 2018-12-21 | 南京理工大学 | A kind of pneumatic software gripper of articulated type endoskeleton |
| CN110270987A (en) * | 2019-06-26 | 2019-09-24 | 清华大学深圳研究生院 | Gas drive moves software climbing robot and its manufacture and control method |
| CN110293545A (en) * | 2019-07-29 | 2019-10-01 | 中凯宝智能机器人科技(苏州)有限公司 | The Kinematic Model method of the snakelike arm of variation rigidity software |
| CN110509266A (en) * | 2019-09-12 | 2019-11-29 | 上海大学 | A kind of four chamber variation rigidity pneumatic muscles gripper equipments |
-
2020
- 2020-06-29 CN CN202010603763.0A patent/CN111796520A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109048980A (en) * | 2018-09-14 | 2018-12-21 | 南京理工大学 | A kind of pneumatic software gripper of articulated type endoskeleton |
| CN110270987A (en) * | 2019-06-26 | 2019-09-24 | 清华大学深圳研究生院 | Gas drive moves software climbing robot and its manufacture and control method |
| CN110293545A (en) * | 2019-07-29 | 2019-10-01 | 中凯宝智能机器人科技(苏州)有限公司 | The Kinematic Model method of the snakelike arm of variation rigidity software |
| CN110509266A (en) * | 2019-09-12 | 2019-11-29 | 上海大学 | A kind of four chamber variation rigidity pneumatic muscles gripper equipments |
Non-Patent Citations (2)
| Title |
|---|
| BANGCHU YANG等: "Monitoring and Control of Position and Attitude of Flexible Manipulator with Three Degrees of Freedom", 《2019 IEEE 4TH INTERNATIONAL CONFERENCE ON ADVANCED ROBOTICS AND MECHATRONICS (ICARM)》 * |
| 王文彪: "气动软体触手机器人的设计与性能研究", 《中国优秀博硕士学位论文全文数据库(硕士) 信息科技辑》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114670214A (en) * | 2022-02-24 | 2022-06-28 | 南京理工大学 | Pneumatic soft robot with self-sensing function |
| CN114670214B (en) * | 2022-02-24 | 2023-09-05 | 南京理工大学 | Pneumatic soft robot with self-sensing function |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Zhang et al. | Design and modeling of a parallel-pipe-crawling pneumatic soft robot | |
| Trivedi et al. | Optimal, model-based design of soft robotic manipulators | |
| De Volder et al. | Fabrication and control of miniature McKibben actuators | |
| Zhang et al. | Optimization and implementation of a high-speed 3-DOFs translational cable-driven parallel robot | |
| Verrelst et al. | Second generation pleated pneumatic artificial muscle and its robotic applications | |
| WO2020216155A1 (en) | Three-dimensional static modeling method of cable-driven continuous robotic arm | |
| CN109325315A (en) | A kind of statics modeling method of continuous type mechanical arm | |
| Huang et al. | Statics of continuum space manipulators with nonconstant curvature via pseudorigid-body 3R model | |
| CN110142760B (en) | Software climbing robot modeling method | |
| Xie et al. | Design and modeling of a hydraulic soft actuator with three degrees of freedom | |
| Gao et al. | Inverse kinematics and workspace analysis of a 3 DOF flexible parallel humanoid neck robot | |
| Zhang et al. | Workspace analysis and optimal design of a translational cable-driven parallel robot with passive springs | |
| CN111796520A (en) | Modeling method and modeling system for soft robot, electronic device, and storage medium | |
| Buffinton et al. | Investigating the mechanics of human-centered soft robotic actuators with finite element analysis | |
| Zhu et al. | Research and application of a multi-degree-of-freedom soft actuator | |
| Zhang et al. | Modeling and experimental study of a novel multi-DOF parallel soft robot | |
| CN109434838B (en) | Coordinated motion planning method and system for endoscopic operation of line-driven continuous robot | |
| Cao et al. | A novel pneumatic gripper driven by combination of soft fingers and bellows actuator for flexible grasping | |
| Wang et al. | General kinetostatic modeling and deformation analysis of a two-module rod-driven continuum robot with friction considered | |
| Chen et al. | Kinematics modeling of soft manipulator interacting with environment using segmented variable curvature method | |
| Liu et al. | Design and application of integrated parabolic soft actuator | |
| CN211992986U (en) | Flexible mechanical arm based on SMA drive multi-section rigid-flexible coupling | |
| Zhang et al. | Fabrication, mechanical modeling, and experiments of a 3D-motion soft actuator for flexible sensing | |
| CN212399657U (en) | Flexible mechanical arm based on fluid multi-channel structure | |
| Chen et al. | Design and modeling of a novel soft parallel robot driven by endoskeleton pneumatic artificial muscles |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20201020 |
|
| WD01 | Invention patent application deemed withdrawn after publication |