System identification method and related equipment for omnidirectional common hull

Abstract

The present application discloses a system identification method and related equipment for an omnidirectional common hull, which is used to improve the accuracy of identifying the dynamic parameters of a robot. The method of the present application includes: establishing an initial dynamic equation of the robot in a target fluid, where the unknown parameters include the resultant force τ of multiple propulsion devices, the robot's mass matrix M, the force matrix C corresponding to the Coriolis force and centrifugal force on the robot, and the robot's dynamic damping matrix D; determining the resultant force τ of the multiple propulsion devices under simulation instructions; determining M and C based on the robot's added mass and the robot's mass, respectively; determining the fluid resistance effect on the robot's movement in the target fluid based on the robot's target motion curve in the target fluid, and determining D based on the fluid resistance effect on the robot's movement in the target fluid and the added mass; and determining the target dynamic equation of the robot in the target fluid based on τ, M, C, and D.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of surface robots, and in particular to a system identification method and related equipment for omnidirectional common hulls. Background Art

[0002] In recent years, with the development of robotics-related technologies, underwater robots have also developed rapidly and have been applied to many fields. The multi-field application of underwater robots has continuously put forward new requirements for the design and control of underwater robots.

[0003] To achieve the control of the surface robot, it is necessary to first establish the initial dynamic motion equation of the surface robot, and then identify the unknown dynamic parameters in the initial dynamic motion equation based on the existing empirical formula to obtain the target dynamic motion equation for controlling the operation of the surface robot.

[0004] However, the existing empirical formulas are constructed based on ship-shaped hulls, and the identification accuracy of unknown dynamic parameters in the initial dynamic motion equations for cylindrical and other non-ship-shaped hulls is insufficient, which in turn limits the improvement of the motion control accuracy of surface robots with cylindrical and other non-ship-shaped hulls. Summary of the Invention

[0005] The embodiments of the present application provide a system identification method and related equipment for an omnidirectional common hull, which are used to improve the identification accuracy of the robot's dynamic parameters.

[0006] In a first aspect, an embodiment of the present application provides a system identification method applied to an omnidirectional robot, the robot comprising: a hull having omnidirectional commonality and a plurality of propulsion devices for providing power to the hull, wherein each of the propulsion devices is not linearly mounted on the hull; the method comprising:

[0007] Establishing an initial dynamic equation for the robot in the target fluid, the initial dynamic equation containing unknown parameters, including a resultant force expression τ of the plurality of propulsion devices, a mass matrix M of the robot, a force matrix expression C corresponding to the Coriolis force and centrifugal force exerted on the robot, and a dynamic damping matrix expression D of the robot;

[0008] Determining a resultant force expression τ of the plurality of propulsion devices under simulation instructions;

[0009] Determine M and C according to the additional mass of the robot in the target fluid and the mass of the robot;

[0010] Determining the influence of fluid resistance on the movement of the robot in the target fluid according to a target motion curve of the robot in the target fluid, and determining D according to the influence of fluid resistance on the movement of the robot in the target fluid and the additional mass;

[0011] The target dynamic equation of the robot in the target fluid is determined according to τ, M, C and D.

[0012] In a specific implementation, determining the influence of fluid resistance on the movement of the robot in the target fluid according to the target motion curve of the robot in the target fluid includes:

[0013] determining the type of target motion based on the expanded form of the initial dynamic equation;

[0014] constructing a target motion curve of the resultant force and motion speed of the plurality of propulsion devices of the robot during the target motion according to the type of the target motion;

[0015] The influence of fluid resistance on the robot when it moves in the target fluid is determined according to the target motion curve.

[0016] In a specific implementation, determining the resultant force expression τ of the plurality of propulsion devices under the simulation instruction includes:

[0017] measuring the thrust generated by each of the propulsion devices under the simulation instruction using the force measuring device;

[0018] The τ is calculated according to the position at which each of the propulsion devices is installed on the hull and the thrust generated by each of the propulsion devices under the simulation command.

[0019] In a specific implementation, the initial dynamic equation is the dynamic equation of the robot moving on the surface of the target fluid; the additional mass includes the longitudinal additional mass of the robot moving in the target fluid along the bow direction of the hull, the lateral additional mass moving in the direction perpendicular to the bow direction, and the rotational additional mass rotating along the hull center of the hull.

[0020] In a specific implementation, the hull is a cylindrical hull.

[0021] A second aspect of an embodiment of the present application provides a system identification device for an omnidirectional common hull, comprising:

[0022] a construction unit, configured to establish an initial dynamic equation of the robot in a target fluid, wherein the initial dynamic equation contains unknown parameters, the unknown parameters including a resultant force expression τ of a plurality of the propulsion devices, a mass matrix expression M of the robot, a force matrix expression C corresponding to the Coriolis force and the centrifugal force exerted on the robot, and a dynamic damping matrix expression D of the robot;

[0023] a determining unit, configured to determine a resultant force expression τ of the plurality of propulsion devices under a simulation instruction;

[0024] The determining unit is further configured to respectively determine M and C according to the additional mass of the robot in the target fluid and the mass of the robot;

[0025] The determining unit is further configured to determine an influence of fluid resistance on the movement of the robot in the target fluid according to a target motion curve of the robot in the target fluid, and determine D according to the influence of fluid resistance on the movement of the robot in the target fluid and the additional mass;

[0026] The determining unit is further configured to determine a target dynamic equation of the robot in a target fluid according to τ, M, C, and D.

[0027] In a specific implementation, the determining unit is specifically configured to determine the type of target motion according to the expansion of the initial dynamics equation;

[0028] constructing a target motion curve of the resultant force and motion speed of the plurality of propulsion devices of the robot during the target motion according to the type of the target motion;

[0029] The influence of fluid resistance on the robot when it moves in the target fluid is determined according to the target motion curve.

[0030] In a specific implementation, the determining unit is specifically configured to measure the thrust generated by each of the propulsion devices under the simulation instruction according to the force measuring device;

[0031] The τ is calculated according to the position at which each of the propulsion devices is installed on the hull and the thrust generated by each of the propulsion devices under the simulation command.

[0032] In a specific implementation, the initial dynamic equation is the dynamic equation of the robot moving on the surface of the target fluid; the additional mass includes the longitudinal additional mass of the robot moving in the target fluid along the bow direction of the hull, the lateral additional mass moving in the direction perpendicular to the bow direction, and the rotational additional mass rotating along the hull center of the hull.

[0033] In a specific implementation, the hull is a cylindrical hull.

[0034] A third aspect of an embodiment of the present application provides a system identification device, including:

[0035] CPU, memory and input / output interfaces;

[0036] The memory is a transient storage memory or a persistent storage memory;

[0037] The central processing unit is configured to communicate with the memory and execute instructions in the memory to perform the method described in the first aspect.

[0038] A fourth aspect of the embodiments of the present application provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the method described in the first aspect.

[0039] A fifth aspect of an embodiment of the present application provides a computer storage medium, wherein the computer storage medium stores instructions. When the instructions are executed on a computer, the computer executes the method described in the first aspect.

[0040] It can be seen from the above technical solution that the embodiments of the present application have the following advantages: the robot has an isotropic hull, and the influence of the fluid resistance on the robot's movement in the target fluid is determined according to the motion curve of the robot in the target fluid, rather than being calculated based on the empirical formula for the ship type hull. The calculated fluid resistance influence parameters are more accurate, and the target dynamic equation is also more accurate, thereby providing a solution for improving the robot's motion control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A schematic diagram of a flow chart of the system identification method disclosed in an embodiment of the present application;

[0042] Figure 2a A schematic diagram of a three-dimensional structure of a robot disclosed in an embodiment of the present application;

[0043] Figure 2b The embodiment disclosed in this application Figure 2a A top view of

[0044] Figure 3 This is an example diagram of the power distribution disclosed in the embodiment of this application;

[0045] Figure 4a An example diagram of a motion curve disclosed in an embodiment of the present application;

[0046] Figure 4b Another example diagram of the motion curve disclosed in the embodiment of the present application;

[0047] Figure 5 A schematic diagram of the structure of the system identification device disclosed in the embodiment of this application;

[0048] Figure 6 This is another structural diagram of the system identification device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] Traditional hull designs for surface robots currently rely primarily on ship-shaped hulls, including monohulls and catamarans. Furthermore, specialized surface robots for specialized applications are beginning to employ redundant propulsion systems, using four or even more propellers. This increases the control complexity and redundancy of surface robots, and consequently, increases manufacturing costs.

[0051] The existing design and control methods of surface robots have the following two main deficiencies:

[0052] First, the surface robot has different resistance in each direction and poor omnidirectional maneuverability.

[0053] While the boat-shaped design ensures relatively low water resistance during forward motion, it also results in a large turning radius and poor turning maneuverability, resulting in a lack of efficient high-speed maneuverability and even inability to move in all directions. The boat-shaped hull design minimizes water resistance along the bow during motion, while exerting greater lateral forces. However, varying forces during maneuvering can severely disrupt the robot's motion, leading to capsizing. These varying forces in all directions can create inconvenience and even threaten the robot's directional movement.

[0054] Second, the robot’s own system parameters are unknown and difficult to identify.

[0055] Existing robot parameter identification methods are primarily based on empirical formulas. However, these formulas are primarily tailored to ship hulls. Experiments with omnidirectional hull types, such as circular ones, are limited, and there is a lack of relevant technical summaries and empirical formulas.

[0056] Based on the above problems, the embodiments of the present application provide a system identification method and related equipment for an omnidirectional common hull, which are used to improve the identification accuracy of the robot's dynamic parameters.

[0057] See also Figure 1 The present invention provides a system identification method for an omnidirectional hull, which is applied to an omnidirectional robot. The robot includes: an omnidirectional hull and a plurality of propulsion devices for providing power to the hull, wherein each propulsion device is unequally mounted on the hull. The system identification method for the robot includes the following steps 101 to 105:

[0058] 101. Establish the initial dynamic equation of the robot in the target fluid. The initial dynamic equation contains unknown parameters, including the resultant force expression τ of multiple propulsion devices, the mass matrix expression M of the robot, the force matrix expression C corresponding to the Coriolis force and centrifugal force acting on the robot, and the dynamic damping matrix expression D of the robot.

[0059] The system identification method for a robot provided in the embodiments of the present application is primarily intended for a robot operating in a stationary state (where the target fluid is in a calm state when the robot is in motion), having an omnidirectional hull, and operating on the surface (water surface) of a target fluid, where the target fluid can be seawater or lake water, without limitation. Furthermore, to simplify calculations, the system identification method in the embodiments of the present application assumes that the target fluid is an infinite fluid, i.e., that the target fluid has no boundaries, i.e., the boundaries of the target fluid do not affect the robot's motion.

[0060] In some specific embodiments, the initial kinetic equation can be established as follows

[0061]

[0062] Where τ is the resultant force expression of multiple propulsion devices, τ E is the environmental force of the robot moving in the target fluid (i.e., the force causing the robot to move due to the action of waves in the environment of the target fluid, and this item is 0 when the robot in the embodiment of the present application works in a stationary state), M is the mass matrix of the robot (i.e., the sum of the mass of the robot and the equivalent mass generated by the robot moving in the target fluid), C is the force matrix expression corresponding to the Coriolis force and centrifugal force generated by the robot due to the rotational motion, D is the dynamic damping matrix expression of the robot (i.e., the expression of the sum of the attenuation effects generated by the robot moving in the target fluid), and v is the movement speed of the robot in the target fluid (including the translational motion speed and the rotational motion speed in the target fluid).

[0063] The above initial dynamic equation can be expressed as the force on the right side of the equal sign, and the acceleration and attenuation motion of the object generated by the force (on the right side of the equal sign) on the left side of the equal sign. The dynamic system represented by the entire initial dynamic equation can be regarded as a similar spring-damper system.

[0064] 102. Determine the resultant force expression τ of multiple propulsion devices under simulation instructions.

[0065] After the initial dynamic equation of the robot in the target fluid is determined in step 101, the expression of each unknown parameter can be calculated.

[0066] This step requires determining the resultant force expression τ for multiple propulsion devices under simulation instructions. A simulation instruction contains instructions for each propulsion device of the robot. The resultant force expression τ must be determined for the robot's multiple propulsion devices under all simulation instructions.

[0067] In some embodiments, τ can be determined by the following steps: measuring the thrust generated by each propulsion device under simulated instructions according to a force measuring device; calculating τ according to the position where each propulsion device is installed on the hull and the thrust generated by each propulsion device under simulated instructions.

[0068] Specifically, after the robot is designed, the operator does not know the thrust generated by each propulsion unit when sending a command to it. Therefore, a force measuring device is required to measure the thrust generated by each propulsion unit under simulated commands. τ is then calculated by synthesizing the thrust generated by each propulsion unit under simulated commands and the position vector of each propulsion unit installed on the hull.

[0069] 103. Determine M and C based on the additional mass of the robot in the target fluid and the mass of the robot, respectively.

[0070] When solving M, it is necessary to calculate the unknown additional mass in M through empirical formulas in the shipbuilding industry and lookup tables (including but not limited to tables such as the added mass moment of inertia of cylindrical structures in ship engineering and the added mass of three-dimensional objects in infinite fluids), and fill the calculated additional mass into the corresponding position in C. Then, M (specific value) and C (a matrix that does not contain unknown parameters and contains the variable v) can be obtained.

[0071] 104. Determine the influence of fluid resistance on the movement of the robot in the target fluid based on the target motion curve of the robot in the target fluid, and determine D based on the influence of fluid resistance on the movement of the robot in the target fluid and the additional mass.

[0072] The motion curve of the robot's specified motion type in the target fluid (i.e., the target motion curve) can be used to solve the fluid resistance effect on the robot's movement in the target fluid. Then, based on the fluid resistance effect on the robot's movement in the target fluid and the added mass, D can be determined (a matrix containing no unknown parameters and containing the variable v is obtained).

[0073] In some specific embodiments, this step can be achieved by: determining the type of target motion based on the expansion of the initial dynamic equation; constructing a target motion curve of the resultant force of multiple propulsion devices and the motion speed of the robot in the target motion based on the type of target motion; and determining the influence of fluid resistance on the robot's movement in the target fluid based on the target motion curve.

[0074] First, M and C calculated in step 103 are entered into the initial motion equation of step 101, and the motion equation is expanded to include M and C calculated in step 103. The type of target motion is then determined based on the expanded equation (which includes M and C calculated in step 103). Next, a target motion curve is constructed for the combined force and velocity of the robot's multiple propulsion devices during the target motion (i.e., the two variables of the target motion curve are τ and v, respectively). Finally, the fluid resistance affecting the robot's movement in the target fluid is determined based on the target motion curve and the expanded equation.

[0075] 105. Determine the target dynamic equation of the robot in the target fluid based on τ, M, C and D.

[0076] According to the above steps, we obtain τ (τ under different simulation instructions), M (a matrix that does not contain variables and unknown parameters), C (a matrix that does not contain unknown parameters and contains variable v), D (a matrix that does not contain unknown parameters and contains variable v) and the initial dynamic equation, and determine the target dynamic equation that does not contain unknown parameters.

[0077] In this embodiment, the robot has an isotropic hull. The fluid resistance effect on the robot's movement in the target fluid is determined based on the robot's motion curve in the target fluid, rather than calculated based on empirical formulas for the ship type and hull. The calculated fluid resistance effect parameters are more accurate, and the target dynamic equations are also more accurate, thereby providing a solution for improving the robot's motion control accuracy. The system identification method provided by the embodiment of the application provides the possibility of further control of the isotropic omnidirectional hull and other tasks, thereby expanding the capabilities of the surface robot and creating more possibilities for the surface robot to perform more complex tasks, such as rapid turns and obstacle avoidance.

[0078] Based on the aforementioned robot system identification method, the system identification method provided by the implementation of this application will be described below in some specific scenarios.

[0079] The system identification method provided by the present application can be applied to a surface robot with the following structure.

[0080] The present application embodiment provides a Figure 2a as well as Figure 2b The robot's structural design is shown. The robot's hull includes but is not limited to a hull bottom surface 201, a hull shell 203, a power supply 205, and a propulsion device 206. The propulsion device 206 can be multiple propellers, multiple bidirectional propellers, or multiple forward and reverse motors plus a drive shaft, without limitation. The hull shell 203 is a cylindrical structure, connected to the hull bottom surface 201 through appropriate design. This cylindrical design ensures isotropic resistance in the water when the robot moves on the surface.

[0081] In some specific embodiments, the bottom surface of the hull may have a propulsion device installation hole 207, and the propulsion device 206 is installed through the propulsion device installation hole 207 ( Figure 2b Only one set is marked; in practice, any propulsion device can be mounted via the propulsion device mounting holes (see Figure 20). The power and control cables for propulsion device 206 can be connected to the power control unit 209 and power output unit 210 within the robot's hull via the propulsion device mounting holes 207.

[0082] Furthermore, to ensure the waterproof performance of the robot hull during underwater operation, the robot hull may further include a hull top surface, a hull connection support column fixing position 208 on the hull bottom surface 201, a hull connection support column fixing position on the hull top surface, and a hull connection support column 202. The hull connection support column 202 cooperates with the hull connection support column fixing positions on the hull top surface and the hull bottom surface 201 to fixedly connect the hull top surface and the hull bottom surface 201, thereby forming the internal space of the robot hull. Furthermore, to provide different sizes of internal spaces of the robot hull, hull connection support columns 208 of different specifications and lengths can be used.

[0083] To further ensure the waterproof performance of the robot hull during underwater operation, the hull bottom surface 201, the hull shell 203, and the hull top surface can be tightly coupled to seal the robot hull. At the same time, all holes and contact points of the robot hull are further sealed with waterproof glue, sealing rubber pads, and / or sealing rubber rings to ensure the waterproof performance of the robot hull during underwater operation. Specifically, if sealing is performed using sealing rubber pads and / or sealing rubber rings, the waterproof performance of the robot hull during underwater operation can be ensured by forming grooves and placing sealing rubber pads and / or sealing rubber rings in the grooves.

[0084] In practical applications, considering the cost of robot manufacturing, the hull (including but not limited to the hull top surface, hull bottom surface 201, and hull shell 203) can be made of commercially available acrylic sheet materials to reduce the high cost of custom processing due to the unique structure of the hull design. It is understood that any device material that can achieve a sealed structure can be used as the hull material, and this is not specifically limited here.

[0085] It is understandable that in order to facilitate the carrying and transportation of the robot, the top surface of the hull may further include a portable handle 204 .

[0086] In some specific embodiments, the top surface of the hull can be provided with a wired communication and / or charging interface to allow wired information transmission and power supply charging of the robot. The top surface of the hull can also be provided with a sensor installation space for installing different sensors and devices such as ultrasonic radars, cameras, etc. In some specific embodiments, the sensor installation space can be installed with Figure 2b The onboard vision unit 213 is shown. A control center 211 and a control center power supply 212 can also be provided on the bottom surface 201 of the hull.

[0087] It is understandable that in order to achieve rapid construction of the robot platform in a more economical manner, all materials, hulls and units in this embodiment can be of modular design.

[0088] It can be known that the robot structure design provided in the embodiment of the present application includes but is not limited to Figure 2a 、 Figure 2b And the modules shown in the aforementioned embodiments.

[0089] In this embodiment, 1. The cylindrical omnidirectional body design and the omnidirectional drive with three propellers give the surface robot in this scheme the ability to move in all directions, and reduce the problem of hull instability or even capsizing caused by uneven forces in different directions caused by the robot body structure.

[0090] Furthermore, the system identification method of the surface robot based on the omnidirectional commonality of the aforementioned robot structure design can be implemented in the following way:

[0091] Specifically, the system identification method is based on physics formulas, which are used to deduce the relationship between motion and force. By collecting information about force and motion, the robot's system parameters and the parameters of its movement in water are obtained.

[0092] This embodiment mainly includes the following two aspects: 1. Measuring the thrust of the propeller and the resultant force of each propeller of the robot. 2. Measuring the movement of the robot under the action of a given force.

[0093] (1) Based on the principle of system identification, the initial dynamic equation is determined according to the dynamic model of the surface robot

[0094]

[0095] Where τ is the resultant force expression of multiple propulsion devices, τ E is the environmental force of the robot moving in the target fluid (i.e., the force that causes the robot to move due to the wave action in the environment of the target fluid, and the robot in the embodiment of the present application works in a stationary state and this item is 0), M is the mass matrix of the robot (i.e., the sum of the mass of the robot and the equivalent mass generated by the robot moving in the target fluid), C is the force matrix expression corresponding to the Coriolis force and centrifugal force generated by the robot due to the rotational motion, D is the dynamic damping matrix expression of the robot (i.e., the expression of the sum of the attenuation effects generated by the robot moving in the target fluid), and v is the movement speed of the robot in the target fluid (including the translational motion speed and the rotational motion speed in the target fluid).

[0096] The above initial dynamic equation can be expressed as the force on the right side of the equal sign, and the acceleration and attenuation motion of the object generated by the force (on the right side of the equal sign) on the left side of the equal sign. The dynamic system represented by the entire initial dynamic equation can be regarded as a similar spring-damper system.

[0097] Next, we first determined the expression for τ on the right side of the equation. Specifically, we used a force measuring device to measure the thrust generated by each propeller under different simulation commands. We then performed vector synthesis of the resultant force based on the point and direction of application of each force.

[0098] Please refer to the power distribution of the water surface robot Figure 3 In some specific embodiments, the surface robot follows the principle of motion on the water surface, and the motion direction can be decomposed into longitudinal movement along the bow direction, transverse movement perpendicular to the bow direction, and rotation along the central axis of the hull, where the bow direction is Figure 3 The direction indicated by arrow 1 (white arrow). The equivalent forces of the robot along the three motion directions are expressed as the equivalent force F of longitudinal motion u , the equivalent force of lateral motion F v and the equivalent force T of rotational motion τ The equivalent force in each direction of motion can be calculated from the thrust F of propeller A. A , the thrust F of propeller B B and the thrust F of propeller C C Expressed as:

[0099]

[0100]

[0101] T τ =(F A +F B +F C )*d

[0102] Finally, let τ = [F u ,F V ,T τ ], so far, we can get the value on the right side of the above initial dynamic equation.

[0103] It can be known that the motion direction decomposition method of the embodiment of the present application can also have other decomposition methods according to needs, which are not specifically limited here.

[0104] (2) First, calculate the unknown additional mass in M according to the empirical formula table of ship engineering (including but not limited to the table of the additional mass moment of inertia of cylindrical structures in ship engineering and the additional mass of three-dimensional objects in infinite fluids), and fill the calculated additional mass into the corresponding position in C, so that M (get the specific value) and C (get the matrix that does not contain unknown parameters and contains the variable v) can be obtained.

[0105] Specifically,

[0106] in,

[0107] x g The x-axis offset of the robot force analysis coordinate axis and the robot motion direction decomposition coordinate axis, y g The y-axis offset of the robot force analysis coordinate axis and the robot motion direction decomposition coordinate axis, is the coupled additional mass along the Y axis caused by the acceleration of the rotational motion, The coupled additional mass along the Z axis is caused by the acceleration of the lateral motion.

[0108] First, simplify M and C(v), considering the embodiment of this application The value of The value of The value of The value of The values of are quite different, and The value of The value relative to The value of The value of The value of is smaller, so ignore as well as At the same time, in order to facilitate calculation, the origin of the robot force analysis coordinate axis and the origin of the robot motion direction decomposition coordinate axis are placed at the same point, then x g and y g The value of is 0. According to the above analysis, the simplified M and C(v) are as follows:

[0109]

[0110]

[0111] The empirical formula can be used to solve as well as in It represents the hydrodynamic additional mass caused by the movement of the robot in the water along the X-axis (longitudinal direction) under the action of external force. It represents the hydrodynamic additional mass caused by the movement of the robot along the Y-axis (lateral direction) in water under the action of external force. This represents the hydrodynamic mass caused by the robot's rotational motion in the water along the Z-axis (the center axis of the hull) due to external forces. The coordinate axis origin is the robot's center of mass, and this axis represents the decomposition of the robot's motion direction.

[0112] Then, based on the longitudinal motion, lateral motion, and rotational motion of the surface robot on the two-dimensional water surface, the initial kinematic equation can be expanded to obtain the following expansion:

[0113]

[0114]

[0115]

[0116] Among them, m is the mass of the robot itself, I z is the moment of inertia of the robot rotating along the Z axis, where I z The robot can be divided into two groups according to its own mass m and the radius of the robot hull (which can be as follows Figure 3 (as shown in d) calculation. In water, due to the design of the circular hull, the difference from the common hull is mainly concentrated in X u 、Y v and N r .in as well as It is mainly related to the robot's own mass m, and there is an empirical formula that can be directly solved (refer to the above content for the specific solution method). The following mainly explains X u 、Y v and N r The solution of Xu Indicates the effect of water resistance when moving along the X axis; Y v Indicates the effect of water resistance when moving along the Y axis, N r Indicates the effect of water resistance when rotating along the Z axis.

[0117] Based on the expanded form of the aforementioned initial dynamic equation, it can be seen that the motion curves of the robot under uniform linear motion, uniform rotational motion in place, and uniform large circular motion are constructed, and the resultant force of all the propulsion devices of the robot and the motion information of the robot (including but not limited to position, time, and acceleration, where the speed can be calculated based on position, time, and / or acceleration) are recorded at each moment.

[0118] In some specific embodiments, the motion trajectory of the robot at different moments in different motions can be recorded, and the following can be obtained: Figure 4a The robot's trajectory during different motions is shown, from left to right, as uniform linear motion, uniform rotation in place, and uniform large circular motion. Based on the robot's trajectory and the time spent at each point, the robot's velocity at each point (or time) can be calculated.

[0119] Furthermore, to reduce accidental errors, please refer to Figure 4b (From left to right, they are the motion curves of uniform linear motion, uniform rotational motion in place, and uniform large circular motion). The motion curves of the robot under different motions may include multiple motion curves of the robot under the corresponding motion, and then the multiple curves of the robot under each motion are integrated for subsequent calculation. It is understandable that the number of motion trajectories under different motions in this embodiment is not limited to Figure 4b The three shown in FIG can also be two or five, which is not limited here.

[0120] When the robot is moving in a uniform linear motion, the robot's lateral velocity v and longitudinal acceleration are 0. In the above expansion, Can be simplified to -X u u=τ u Where u is the longitudinal velocity of the robot, which can be determined from the motion information of the robot in uniform linear motion; F u is the equivalent force of the robot's longitudinal motion, which can be determined based on the thrust of each propulsion device in the robot's uniform linear motion and the position of each recommended device installed on the robot's hull (see the above content for the specific determination method). u and F u After confirmation, we can directly solve X u .

[0121] Similarly, N can be solved according to the uniform rotation motion in place r According to the uniform great circular motion, Y can be solvedv .

[0122] Specifically, when the robot performs uniform large circular motion, the above expansion can be solved Y in v . Among them, m is the mass of the robot itself, is the robot's lateral acceleration, which can be determined from the robot's motion information in uniform large circular motion; u is the robot's longitudinal speed, which can be determined from the robot's motion information in uniform large circular motion; r is the robot's rotational speed, which can be determined from the robot's motion information in uniform large circular motion; v is the robot's lateral speed, which can be determined from the robot's motion information in uniform large circular motion; F v It is the equivalent force of the robot's rotational motion, which can be determined based on the thrust of each propulsion device during the robot's uniform rotation in place and the position of each propulsion device installed on the robot's hull (see the above content for specific determination methods). u, r, v, and F v After determination, the value determined based on the above calculation of M and C(v) is as well as Y can be directly solved v .

[0123] When the robot performs a uniform rotation in place, the robot's rotational acceleration The longitudinal speed u and the lateral speed v are 0, and the above expansion Can be simplified to -N r r=T τ Where r is the rotation speed of the robot, which can be determined from the motion information of the robot in the uniform rotation motion in place; T τ is the equivalent force of the robot's rotational motion, which can be determined based on the thrust of each propulsion device during the robot's uniform rotation in situ and the position of each recommended device installed on the robot's hull (see the above content for the specific determination method), r and T τ After confirmation, N can be directly solved r .

[0124] At this point, the parameters of the entire system can be fully solved, providing a good basis for further control and path tracking of the robot.

[0125] With reference to the above embodiments, it can be known that the motion curve of the robot under the target motion can be the motion trajectory of the robot under the target motion or the resultant force and velocity curve of the robot under the target motion, as long as the speed of the robot at different times (or positions, not limited here) under the target motion and the thrust of the propulsion device at different times (or positions, not limited here) can be directly or indirectly obtained from the motion curve. Furthermore, it is possible not to construct a motion curve, but to construct a table to directly or indirectly know the speed of the robot at different times (or positions, not limited here) under the target motion and the thrust of the propulsion device at different times (or positions, not limited here). The embodiments of the present application do not solve X u , N r and Y v In the process of target motion, how to determine the speed of the robot at different times (or positions, not limited here) and the thrust of each propulsion device at different times (or positions, not limited here) are specifically defined.

[0126] For a surface robot with a relatively symmetrical hull structure (such as a hemispherical one), a similar experimental method can be obtained for the cylindrical hull. The motion types recorded in the experiment are still uniform linear motion, uniform rotation in place, and uniform large circular motion.

[0127] Based on the above-mentioned embodiments, the robot structure design of this application adopts a modular design concept. Each part of the entire system can be quickly replaced, making it easy to carry and expand. In addition, the comprehensive body design and system parameter identification method greatly improve the maneuverability of existing surface robots, thereby achieving faster operation and obstacle avoidance, and has good application prospects.

[0128] Potential technology / product application areas and methods include but are not limited to: system identification methods and identification experiment designs for various omnidirectional common hull robots; surface robots serving as guidance units for other large surface robots or directly as their power units; multiple omnidirectional surface robots performing collaborative operations for exploration, patrolling, search and rescue, mapping, collaborative transportation, etc.; as educational teaching aids to promote and popularize surface robot education and scientific training; as mobile surface monitoring stations for collecting water surface environment, hydrological and ecological environment sampling, etc.; as surface formation displays, for surface advertising displays, etc.

[0129] See also Figure 5 The present invention provides a system identification device for an omnidirectional common hull, comprising:

[0130] A construction unit 501 is used to establish an initial dynamic equation of the robot in the target fluid. The initial dynamic equation contains unknown parameters, including the resultant force expression τ of multiple propulsion devices, the mass matrix expression M of the robot, the force matrix expression C corresponding to the Coriolis force and centrifugal force exerted on the robot, and the dynamic damping matrix expression D of the robot;

[0131] A determining unit 502 is configured to determine a resultant force expression τ of the plurality of propulsion devices under a simulation instruction;

[0132] The determining unit 502 is further configured to determine M and C respectively according to the additional mass of the robot in the target fluid and the mass of the robot;

[0133] The determining unit 502 is further configured to determine the influence of fluid resistance on the movement of the robot in the target fluid according to the target motion curve of the robot in the target fluid, and determine D according to the influence of fluid resistance on the movement of the robot in the target fluid and the additional mass;

[0134] The determining unit 502 is further configured to determine a target dynamic equation of the robot in the target fluid according to τ, M, C, and D.

[0135] In a specific implementation, the determining unit 502 is specifically configured to determine the type of target motion according to the expansion of the initial dynamic equation;

[0136] According to the type of target motion, construct the target motion curve of the robot's target motion, including the resultant force of multiple propulsion devices and the motion speed;

[0137] The influence of fluid resistance on the robot's movement in the target fluid is determined based on the target motion curve.

[0138] In a specific implementation, the determining unit 502 is specifically configured to measure the thrust generated by each propulsion device under the simulation instruction according to the force measuring device;

[0139] τ is calculated based on the position of each propulsion device installed on the hull and the thrust generated by each propulsion device under simulation instructions.

[0140] In a specific implementation, the initial dynamic equation is the dynamic equation of the robot's surface motion on the target fluid; the additional mass includes the longitudinal additional mass of the robot moving along the bow direction of the hull in the target fluid, the lateral additional mass of the robot moving in the vertical direction of the bow, and the rotational additional mass of the robot rotating along the center of the hull.

[0141] In a specific implementation, the hull is a cylindrical hull.

[0142] Figure 61 is a schematic diagram of the structure of a system identification device provided in an embodiment of the present application. The system identification device 600 may include one or more central processing units (CPU) 601 and a memory 605. The memory 605 stores one or more application programs or data.

[0143] Memory 605 may be volatile or persistent storage. The program stored in memory 605 may include one or more modules, each of which may include a series of instruction operations in the system identification device. Furthermore, central processing unit 601 may be configured to communicate with memory 605 and execute the series of instruction operations in memory 605 on system identification device 600.

[0144] The system identification device 600 may also include one or more power supplies 602, one or more wired or wireless network interfaces 603, one or more input and output interfaces 604, and / or one or more operating systems, such as Windows Server™, Mac OS X™, Unix™, Linux™, FreeBSD™, etc.

[0145] The CPU 601 can execute the aforementioned Figures 1 to 5 The operations performed by the system identification device in the illustrated embodiment will not be described in detail here.

[0146] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0147] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0148] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0149] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0150] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk, and other media that can store program code.

[0151] An embodiment of the present application further provides a computer program product comprising instructions, which, when executed on a computer, enables the computer to execute the system identification method for the omnidirectional common hull as described above.

Claims

1. A system identification method for omnidirectional common hull, characterized by: A robot applied to omnidirectional commonality, comprising: a hull having omnidirectional commonality and a plurality of propulsion devices for providing power to the hull, wherein each of the propulsion devices is unequally mounted on the hull; The method comprises: Establish an initial dynamic equation of the robot in the target fluid, wherein the initial dynamic equation contains unknown parameters, including the resultant force expression τ of the plurality of propulsion devices, the mass matrix M of the robot, the force matrix expression C corresponding to the Coriolis force and centrifugal force exerted on the robot, and the dynamic damping matrix expression D of the robot; the initial dynamic equation is The τ E is the environmental force of the robot moving in the target fluid, and v is the moving speed of the robot in the target fluid; Determine the resultant force expression τ of the plurality of propulsion devices under the simulation instruction; τ=[F u ,F V ,T τ ], T τ =(F A +F B +F C )*d, the equivalent forces of the robot along the three motion directions are expressed as the equivalent force of longitudinal motion F u , the equivalent force of lateral motion F v and the equivalent force T of rotational motion τ , the equivalent force in each direction of motion can be obtained from the thrust F of propeller A A , the thrust F of propeller B B and the thrust F of propeller C C express; Determine M and C according to the additional mass of the robot in the target fluid and the mass of the robot; in, x g The x-axis offset of the robot force analysis coordinate axis and the robot motion direction decomposition coordinate axis, y g The y-axis offset of the robot's force analysis coordinate axis and the robot's motion direction decomposition coordinate axis is obtained. is the coupled additional mass along the Y axis caused by the acceleration of the rotational motion, is the coupled additional mass along the Z axis caused by the acceleration of the lateral motion, and m is the mass of the robot itself; determining, based on a target motion curve of the robot in the target fluid, an influence of fluid resistance on the movement of the robot in the target fluid, and determining D based on the influence of fluid resistance on the movement of the robot in the target fluid and the additional mass, the target motion curve including a motion curve under uniform linear motion, a motion curve under in-place uniform rotational motion, and a motion curve under uniform large circular motion; The target dynamic equation of the robot in the target fluid is determined according to τ, M, C and D.

2. The method according to claim 1, characterized in that The determining, based on a target motion curve of the robot in the target fluid, an influence of fluid resistance on the movement of the robot in the target fluid, comprises: constructing a target motion curve of the resultant force and motion speed of the plurality of propulsion devices of the robot during the target motion according to the type of the target motion; The influence of fluid resistance on the robot when it moves in the target fluid is determined according to the target motion curve.

3. The method according to claim 1, characterized in that Determining the resultant force expression τ of the plurality of propulsion devices under the simulation instruction includes: measuring the thrust generated by each of the propulsion devices under the simulation instruction using a force measuring device; The τ is calculated according to the position at which each of the propulsion devices is installed on the hull and the thrust generated by each of the propulsion devices under the simulation command.

4. The method according to claim 1, wherein The initial dynamic equation is the dynamic equation of the robot moving on the surface of the target fluid; the additional mass includes the longitudinal additional mass of the robot moving in the target fluid along the bow direction of the hull, the lateral additional mass moving in the direction perpendicular to the bow direction, and the rotational additional mass rotating along the hull center of the hull.

5. The method according to claim 1, wherein The hull is a cylindrical hull.

6. A system identification device for omnidirectional common hull, characterized in that: include: A construction unit is used to establish an initial dynamic equation of a robot in a target fluid, wherein the robot comprises: a hull with omnidirectional commonality and a plurality of propulsion devices for providing power to the hull, wherein each of the propulsion devices is unequally installed on the hull, and the initial dynamic equation contains unknown parameters, wherein the unknown parameters include a resultant force expression τ of the plurality of propulsion devices, a mass matrix expression M of the robot, a force matrix expression C corresponding to the Coriolis force and centrifugal force exerted on the robot, and a dynamic damping matrix expression D of the robot; the initial dynamic equation is The τ E is the environmental force of the robot moving in the target fluid, and v is the moving speed of the robot in the target fluid; A determination unit is used to determine the resultant force expression τ of the plurality of propulsion devices under the simulation instruction; wherein τ=[F u ,F V ,T τ ], T τ =(F A +F B +F C )*d, the equivalent forces of the robot along the three motion directions are expressed as the equivalent force of longitudinal motion F u , the equivalent force of lateral motion F v and the equivalent force T of rotational motion τ , the equivalent force in each direction of motion can be obtained from the thrust F of propeller A A , the thrust F of propeller B B and the thrust F of propeller C C express; The determining unit is further configured to respectively determine M and C according to the additional mass of the robot in the target fluid and the mass of the robot; in, x g The x-axis offset of the robot's force analysis coordinate axis and the robot's motion direction decomposition coordinate axis, g The y-axis offset of the robot force analysis coordinate axis and the robot motion direction decomposition coordinate axis, is the coupled additional mass along the Y axis caused by the acceleration of the rotational motion, is the coupled additional mass along the Z axis caused by the acceleration of the lateral motion, and m is the mass of the robot itself; The determining unit is further configured to determine an influence of fluid resistance on the movement of the robot in the target fluid based on a target motion curve of the robot in the target fluid, and to determine D based on the influence of fluid resistance on the movement of the robot in the target fluid and the additional mass, wherein the target motion curve includes a motion curve under uniform linear motion, a motion curve under in-place uniform rotational motion, and a motion curve under uniform large circular motion; The determining unit is further configured to determine a target dynamic equation of the robot in a target fluid according to τ, M, C, and D.

7. The device according to claim 6, characterized in that The determining unit is specifically configured to determine the type of target motion according to the expanded form of the initial dynamics equation; constructing a target motion curve of the resultant force and motion speed of the plurality of propulsion devices of the robot during the target motion according to the type of the target motion; The influence of fluid resistance on the robot when it moves in the target fluid is determined according to the target motion curve.

8. The device according to claim 6, characterized in that The determining unit is specifically configured to measure the thrust generated by each of the propulsion devices under the simulation instruction using a force measuring device; The τ is calculated according to the position at which each of the propulsion devices is installed on the hull and the thrust generated by each of the propulsion devices under the simulation command.

9. A system identification device, characterized in that: include: CPU, memory and input / output interfaces; The memory is a transient storage memory or a persistent storage memory; The central processing unit is configured to communicate with the memory and execute instructions in the memory to perform the method according to any one of claims 1 to 5.

10. A computer storage medium, characterized in that The computer storage medium stores instructions, which, when executed on a computer, enable the computer to perform the method according to any one of claims 1 to 5.

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