GB2621306A

GB2621306A - Hovercraft high-speed rotation control method based on longitudinal speed planning

Info

Publication number: GB2621306A
Application number: GB2208660.7A
Authority: GB
Inventors: Xu Yujie; Fu Mingyu; Hao Xudong; Jia Zhaowei
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2021-04-30
Filing date: 2021-12-29
Publication date: 2024-02-14
Also published as: GB202208660D0

Abstract

A hovercraft high-speed rotation control method based on longitudinal speed planning, relating to the field of hovercraft motion control. In the method, a navigation speed planning method based on sideslip angle constraint is employed to solve the stall problem of a hovercraft employing traditional nonlinear feedback control during high-speed rotation, thereby ensuring that accurate navigation speed tracking can be realized while a hovercraft rotates, and improving the maneuverability and operation capability of the hovercraft; while it is ensured that an expected heading can be accurately tracked in the high-speed rotation process of the hovercraft, the phenomenon of drifting caused by an overlarge rotation rate is avoided, and the reliability and safety of the hovercraft during high-speed rotation are improved.

Description

SPECIFICATION

HOVERCRAFT HIGH-SPEED ROTATION CONTROL METHOD BASED ON LONGITUDINAL SPEED PLANNING

FIELD OF THE INVENTION

[00011 The invention relates to the field of hovercraft motion control, in particular to a high-velocity rotation control method of hovercraft based on longitudinal velocity planning.

BACKGROUND OF THE RELATED ART

[0002] As a kind of special ship, in the course of sailing, the hovercraft has the advantages of little resistance, fast velocity and high maneuverability because its bottom is not in direct contact with the water surface, which has a broad application prospect in military beach landing and civil rescue and disaster relief, etc. However, due to the structure complexity of the hovercraft (including rigid body and flexible skirt), the relatively large environmental interference existing in the process of sailing with high-velocity leads to large nonlinearity and coupling in the model. At the same time, most. of the hovercrafts are belong to the typical underactuated ships (that is, transverse control force can not be produced) without being provided for transverse actuator, which causes great challenge to the safety control of the hovercraft at high-velocity.

Cr) [0003] There are several difficulties in the high-velocity rotation control of the hovercraft: I) C\J It is impossible to realize that the velocity of the hovercraft can be maintained in the rotation process completely through the feedback control of the longitudinal channel. 2) The underactuated characteristic makes it impossible for the hovercraft to restrict the sideslip angle by directly controlling the lateral velocity. 3) The rotation rate can not be strictly limited within a specified range by the traditional control method based on auxiliary system.

[0004] Due to the above control difficulties, the rotary motion under high-velocity sailing is restricted within a conservative range for the current hovercraft in order to ensure safety, which greatly restricts the performance and application scenario of the hovercraft itself. Therefore, the research on the rotation control of the hovercraft at high-velocity has very important engineering practical value for improving the motion control performance and reliability of the domestic hovercraft.

SUMMARY OF THE INVENTION

[0005] The purpose of the invention is to provide a high-velocity rotation control method of

SPECIFICATION

the hovercraft based on longitudinal velocity planning to realize its safe rotation at a constant expected velocity.

l00061 The purpose of the invention is realized as follows: l00071 The high-velocity rotation control method of hovercraft based on longitudinal velocity planning comprises the following steps: [0008] Step 1: The second order sliding mode observer is designed based on the hovercraft motion model to estimate the uncertainty and disturbance of the system model with longitudinal and rotational degrees of freedom; [0009] The longitudinal and rotary motion models of the hovercraft are as follows: [0010] [0011] Where, mo is the nominal mass of the hovercraft, are the nominal values of C\J longitudinal resistance and rotary resistance moment respectively; Du and D. are the uncertainty of model parameter and the dynamics uncertainty affected by disturbance of random wind respectively.

[0012] The Du and of the model uncertainty and the external disturbance for the CO longitudinal and rotation are estimated by the following second-order sliding model observer: C\J [0013] Longitudinal direction Rotation [0014] et, sIgne,")+ sign(er:Wr -F r (no /no P. VrIe isigti k, )(1,-44_J r.

17, = ^ <1

-

0[0015] Where, kil,>0,k,, >0 k/' > are observer's gains, = 4 is the velocity estimation error. CR r I. is the rotation estimation error.

[0016] Step 2: Longitudinal velocity planning is carried out based on sideslip angle constraint, and longitudinal velocity control law based on logarithmic SBLF method is designed, which ensures that. the hovercraft does not stall in the process of high-velocity rotation.

l00171 Step 2.1: The sideslip angle constraint Oniax is transformed into longitudinal velocity constraint umin tar)[0018] -

SPECIFICATION

[0019] Step 2.2: The longitudinal velocity planning is as follows: [0020] isd(i):= ud (0) Auda 1/c u"( *-uu(4.

[0021] -.11.1nio(r) > [0022] Where, ku >0, 6 >0, cumin >0 are the design parameters. Throne reasonable design of parameters, ud> umin can be guaranteed all the time.

[0023] Step 2.3: The longitudinal control law is designed by SBLF.

[0024] velocity error is defined as: u [0025] tuf-< k (t)= [0026] The first-order sliding model surface is selected as: [0027] s=k [0028] Where k > 0 is the design parameter of the sliding model surface, then [0029] The Lyapunov function is selected as: [00301 V1n [0031] IC is defined, then the above equation can be written as:

I

[0032] 2 1- [00331 It is easy to know that V is continuously differentiable in the set of The following can be obtained by derivating of the above formula: = t -ft!' rn me, min [0035] Where. (-) -k, (1-c (7],

SPECIFICATION

[0036] The design velocity control law is: [0037] rt. =" rri e, k I) IBLF method is designed rotation rate, which avoids [0038] Where n 2>0 is the coefficient of reaching law. designed by backstepping [0039] Step 3: The rotation constraint control law based on the according to the expected heading angle and the given maximum the phenomenon of tail flailing caused by excessive rotation rate. [0040] Step 3.1: The virtual rotational angular velocity or is method [0041] The heading rotation model is: Li [0045] The errors of heading, derivative and rotation rate are defined as: [0046] eth= Th -Thd [0047] cos 0 - [0048] e =r [0049] The first obstacle Lyapunov function is selected as: [0050] r 1 " [0051] The following can be obtained by derivating of the above formula: [00521 = e ec (6, COS 9 1-a COS (0!lid) [0053] The virtual rotation rate is designed as follows: [0054] a 1 (0 COs [0055] Where, ct>0 is the design parameter.

[0056] Step 3.2: Based on the IBLF designed rotation control moment t[0057] The second obstacle Lyapunov function is constructed: [0042] /' COS ',/, [0043] r [0044] - D-The rotation control objective is: 1w

SPECIFICATION o-r

[0058] ex -(a [0059] The following can be obtained by derivating of the above formula: [0064] The design heading control law is: ATi b _ m r [0065] . )e,,, cosi)) I' - [00661 Where, ri1 >0 is the design parameter.

[0067] Compared with the existing technology, the beneficial effects of the invention are: [0068] 1.In the invention, the navigational velocity planning method based on the side slip angle constraint is adopted to solve the stall problem of the hovercraft when the traditional nonlinear feedback control is adopted during high-velocity rotation, which can ensure the accurate velocity tracking of the hovercraft while rotating, and improve the mobility and operational ability of the hovercraft.

[0069] 2.The strict restriction on the rotation rate of the hovercraft is realized by the control method based on IBLF in the invention. The tail flicking phenomenon caused by excessive rotation rate is avoided while ensuring of the accurate (racking of the desired heading for the hovercraft in the process of high-velocity rotation, which improves the reliability and safety of the hovercraft during high-velocity rotation. C? r e.)

[0060] ruth& t,

-car

[0062] [0063] tariff ( tanh +cc Xrinix r L 1x0 [0061] Where, le_ 0 kna%

SPECIFICATION

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 Control block diagram of high-velocity rotation of the hovercraft based on longitudinal velocity planning [00711 Figure 2 Control block diagram of the hovercraft rotation with rotation rate constraint; [0072] Figure 3 Longitudinal velocity estimation and disturbance estimation; [0073] Figure 4 Estimation of rotation rate and rotation direction disturbance; [0074] Figure 5 Longitudinal velocity tracking effect and sideslip angle curve; [0075] Figure 6 Tracking effect curve of heading angle; [0076] Figure 7 The change curve of virtual and actual rotation rates at rffinx=3;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0077] The invention is further described in detail in combination with the attached drawings and specific implementation methods.

[0078] The basic principle block diagram of the invention is shown in Figure 1, and the C\I specific implementation mode is as follows: [0079] 1.Based on the four-degree-of-freedom model of the hovercraft, a second-order sliding model observer is designed to estimate the model uncertainty and disturbance of the system with longitudinal and rotational degrees of freedom; Cr) [0080] Step 1. Establish the four-degree-of-freedom model of the hovercraft C\1 1 ---F. I,p, [0082] Where, in is the mass of the hovercraft, I,, and J, are the rotational inertia around the longitudinal and vertical direction respectively. u, v, p and r are longitudinal velocity, transverse velocity, inclination velocity and rotational angular velocity respectively. FAD, FD, MAD, and MAD respectively represent the corresponding accurate longitudinal resistance, lateral resistance and heeling resistance torque under the current sailing state; Tr and Tr represent longitudinal thrust force and rotational moment respectively.

[0083] Since only the longitudinal direction and rotation of the hovercraft can be controlled, the four-degree of freedom model is simplified as [0081]

SPECIFICATION

[0084] [0085] Where, mo is the nominal mass of the hovercraft, are the nominal values of longitudinal resistance and rotary resistance moment respectively; ll,,and Dr are the uncertainty of model parameter and the dynamics uncertainty affected by disturbance of random wind respectively.

[0086] The and Dr of the model uncertainty and the external disturbance for the longitudinal and rotation are estimated by the following second-order sliding model observer: [0087] Longitudinal direction Rotation 1;s1 [0088] CR [0089] Where, k," > 0, k211 > 0, kir> 0, k2, > 0 are observer's gains, c = U a is the velocity estimation error. eR = r 12 is the rotation estimation error.

Ce [0090] Now the disturbance estimation errors 15"and =r are defined, the estimation errors can reach zero within the following finite time: [00911 to, or td, 7.6e,(0) k.,z, [0092] Where, lo and 1. are upper bounds of the uncertain items in longitudinal and rotational directions, which meet D iff D l.

LI * u r [0093] 2.The maximum sideslip angle constraint is transformed into longitudinal velocity constraint, and then longitudinal velocity planning is carried out according to the expected velocity, and the longitudinal velocity control law based on logarithmic SBLF method is designed, which ensures that the hovercraft does not stall in the process of high-velocity rotation.

[0094] Step 2.1: The sideslip angle constraint 13","" is transformed into longitudinal velocity constrain( Lan

SPECIFICATION

[0095] l00961 It is assumed that the initial velocity satisfies: ilmin (0) <11(0) <211d (0) -11min (0) l00981 Where, the initial expected velocity ua (0) >tun (0) . [0099] Step 2.2: The longitudinal velocity planning is as follows: [0100] if ". /1-- (0)+ Am/ CT [0101] C. 1{4. "tit, u1 (t) 11"vin C\1 C\I [0102] Where, k">0, 6 >0, " >0 are the design parameters. Through reasonable design of parameters, ud> limb can be guaranteed all the time. model surface, then [0103] Step 2.3: The longitudinal control law is designed by SBLF. velocity error is defined as: [01041 t! -LTU< k 01= u [0105] IT."1- [0106] The first-order sliding model surface is selected as: s=ke [0107] Where k > 0 is the design parameter of the sliding [0108] (2) = kV) [0109] The Lyapunov function is selected as: [0110] 1 k2 (t) [01111 2 In ' * ' [0112] A= is defined, then the above equation can be written as: 1. - In

Cr) C\1 [0113] It is easy to know that V is continuously differentiable in the set of Icl<1. The following can be obtained by derivating of the above formula: k (e, - kix [0114] -0.

Mc, Ile

SPECIFICATION

[01151 Where. " )

[0116] Longitudinal velocity control law is designed as follows: 41.

[0117] =ino(-vr D+ e -k s w-k [01181 Where k 5, '72 q 2>0 is the coefficient of reaching law.

[0119] By substituting the control law T p into the above equation, the following equation is obtained: = eAD, -k -Th,sign(s)) ks s 2 hs gn(s-k 2 [0121] Only need to design the switching gain 112 --;=-elm, then there is namely the longitudinal velocity of the hovercraft can gradually converge to the planned expected safe velocity.

[0122] 3.The rotation constraint control law based on the IBLF method is designed according to the expected heading angle and the given maximum rotation rate, which avoids the phenomenon of tail Bailing caused by excessive rotation rate.

[0123] Step 3.1: The virtual rotational angular velocity a is designed by backstepping method [0124] The heading rotation model is: = rcosqY [0125] r. = D

[0126] The rotation control objective is: [0120] -?7 [0127]

SPECIFICATION

[0128] The errors of heading, derivative and rotation rate are defined as: [0129] e = - [0130] e. rrcosØ-Vl 101311 c =r-CT [0132] The first obstacle Lyapunov function is selected as: [0133] [0134] The following can be obtained by derivating of the above formula: = [0135] ev( ).s + -os -tfr) [0136] The virtual rotation rate is designed as follows: 1 [0137] ar k* cosy.) [0138] Where, cw>0 is the design parameter. [0139] Obtained: C\I [0140] 1), [0141] Step 3.2: Based on the IBLF designed rotation control moment Cr) [0142] The second obstacle Lyapunov function is constructed: C\I [0143] o criz, [0144] The following can be obtained by derivating of the above formula: [0145] [0146] Where, [0148] (rtodd (id d- ,d;11.11dKid, Cr..

turd] I I oft) T r

SPECIFICATION

[0149] The partial derivative of P, (er, GT) is: [01501 ?PE [0151] at), * - [0152] From Lobida's Law, the following equation can be obtained: Un, rzr.

[0153] ("?p, and L1-7,' ea-in the neighborhoods of or= 0 is [01541 lim = -a)-7 [0155] So when I a il<rmax, P2 well-defined.

[0158] Where. ri1 >0 is the design parameter.

[01591 By substituting the control torque into the above formula, the the following equation CO can be obtained: C\1 C\1 [01571 C\I 0156] The design heading control law is:

_

-r c

[0160] [0161] The Lyapunov function of the whole rotation control system is selected as: [0162] V= Vi+V2 [0163] Then its derivative is: [0164] [0165] Only need to design the switching gain ni eui can guarantee that the control rotation rate is strictly less than rilux while the hovercraft converges to the expected heading.

Claims

CLAIMS1. The high-velocity rotation control method of hovercraft based on longitudinal velocity planning, which is characterized in that it comprises the following steps: Step 1: The second order sliding mode observer is designed based on the hovercraft motion model to estimate the uncertainty and disturbance of the system model with longitudinal and rotational degrees of freedom; The longitudinal and rotary motion models of the hovercraft are as follows: Where, mo is the nominal mass of the hovercraft, are the nominal values of longitudinal resistance and rotary resistance moment respectively; D" and Dr are the uncertainty of model paramew and the dynamics uncertainty affected by disturbance of random wind respectively.The Du and Dr of the model uncertainty and the external disturbance for the longitudinal and rotation are estimated by the following second-order sliding model observer: Longitudinal direction Rotation Where, k10 >0, k2o > , kir > >0 are observer's gains, .er, = is the velocity estimation error. 'elz is the rotation estimation error.Step 2: Longitudinal velocity planning is carried out based on sideslip angle constraint, and longitudinal velocity control law based on logarithmic SBLF method is designed, which ensures that the hovercraft does not stall in the process of high-velocity rotation.Step 2.1: The sideslip angle constraint floox is transformed into longitudinal velocity constraint u"or, Step 2.2: The longitudinal velocity planning is as follows: Ando- 11,:iEt/Y-CLAIMSWhere, k"> 0, 6> 0, Cumin> 0 are the design parameters. Through reasonable design of parameters, lid> n can be guaranteed all the time.Step 2.3: The longitudinal control law is designed by SBLF. velocity error is defined as: " The first-order sliding model surface is selected as: s=keu Where k > 0 is the design parameter of the sliding model surface, then The Lyapunov function is selected as: hi eft) 2 lc:C.0-s k. is defined, then the above equation can be written as: It is easy to know that V is continuously differentiable in the set of following can be obtained by derivatin2 of the above formula: 0,(a. too<1. The The design velocity control law is: > 0 Where n 2>0 is the coefficient of reaching law.Step 3: The rotation constraint control law based on the IBLF method is designedCLAIMSaccording to the expected heading angle and the given maximum rotation rate, which avoids the phenomenon of tail flailing caused by excessive rotation rate.Step 3.1: The virtual rotational angular velocity u, is designed by backstepping method The heading rotation model is: The rotation control objective is: ")* The errors of heading, derivative and rotation rate are defined as: e = Ilicl r cos e =rGr-The first obstacle Lyapunov function is selected as: The following can be obtained by derivating of the above formula: V, = C 49 a" co, The virtual rotation rate is designed as follows: cosi 9 Where, c,,>() is the design parameter.Step 3.2: The second obstacle Lyapunov function is constructed based on the IBLF designed rotation control moment The following can be obtained by derivating of the above formula:CLAIMSWhere, *** * - 43.,ee:,**: * ' The design heading control law is: Where, ni >0 is the design parameter.