230 results about "Terminal sliding mode" patented technology

The invention discloses a cable underwater robot trajectory tracking control method for coping with ocean current disturbance, and belongs to the technical field of underwater robot trajectory tracking, and the method comprises the following steps: S1, constructing a kinematics and dynamics model of a cable underwater robot, and simplifying the kinematics model of the cable underwater robot; s2, combining speed information of a Doppler velocimeter sensor, designing a super-spiral expansion state observer, and compensating a cable underwater robot system; designing a self-adaptive super-spiral expansion state observer by combining a self-adaptive law; and S3, designing a self-adaptive super-spiral integral terminal sliding mode controller based on the self-adaptive super-spiral expansion state observer. The real-time dynamic performance and stability of the underwater robot in sliding mode control are improved, the buffeting problem existing in sliding mode control is solved, it is ensured that under the condition of ocean current disturbance, the ROV can still achieve accurate trajectory tracking, and the robustness is very high.

A preset time robust sliding mode control method for a mechanical arm system comprises the steps that (1) under the condition that parameter perturbation, joint friction and external disturbance are considered, a dynamic model and a tracking error system model of the mechanical arm system are established; (2) a robust preset time controller is designed to ensure that the speed tracking error of the mechanical arm converges to zero within preset time; 3) designing a non-singular fast terminal sliding mode controller based on a preset time reaching law so as to ensure that a position tracking error can also converge to zero within the preset time; 4) the feasibility and effectiveness of the method are verified by using a Lyapunov stability analysis method; aiming at a mechanical arm system with parameter perturbation, joint friction and external disturbance, the invention develops a robust nonsingular fast terminal sliding mode control method in preset time so as to ensure that the mechanical arm system can accurately track an expected trajectory signal in the preset time, so that the tracking speed of a mechanical arm is improved, and the tracking precision is improved. And the tracking accuracy and safety of the mechanical arm are ensured.

The invention relates to the technical field of mining permanent magnet synchronous motor sensorless control, and particularly discloses a composite sliding mode control and adaptive phase-locked loop collaborative optimization method. Aiming at the technical bottlenecks of a traditional control strategy in the aspects of rotating speed fluctuation suppression, load disturbance compensation and rotor position observation precision, a collaborative architecture of a time-varying integral terminal sliding mode control module, a sliding mode disturbance observation module and a self-adaptive phase-locked loop module is constructed, so that the dynamic performance optimization of the system is realized. According to the method, through the dynamic coupling design of the time-varying gain nonlinear reaching law and the fast integral terminal sliding mode surface, the convergence speed and the buffeting suppression requirement are balanced while the disturbance dynamic influence is eliminated; multi-dimensional decoupling observation of external load disturbance is realized based on a hierarchical disturbance observer architecture, and a disturbance real-time suppression path is established in combination with a feed-forward compensation strategy; and constructing an error self-adaptive correction mechanism of rotor position observation by dynamically adjusting a phase-locked loop proportionality coefficient and a phase compensation parameter. The limitation of parameter solidification and observation coupling in traditional control is broken through, the rotating speed tracking stability, the position observation precision and the anti-interference capability under complex working conditions are remarkably improved, and an innovative solution is provided for a high-precision servo driving system.

The invention discloses a reinforcement learning-based quadrotor unmanned aerial vehicle attitude preset performance control method, which comprises the following steps of: establishing an unmanned aerial vehicle attitude kinetic equation by considering a time-varying inertial parameter and external unknown interference; a sub-channel preset performance controller is constructed, and a robust control quantity is generated in combination with preset performance and a non-singular fast terminal sliding mode control technology; designing a reinforcement learning parameter generator, and dynamically optimizing 12 time-varying parameter estimated values through a time sequence feature extraction network and a residual network; and establishing an online reinforcement learning training mechanism, constructing a multi-target reward function, and optimizing the output of the parameter generator through the multi-target reward function. According to the method, a reinforcement learning method is adopted to replace a traditional self-adaptive method to estimate time-varying parameters, multi-degree-of-freedom decoupling optimization is achieved through a sub-channel control architecture, tracking error preset performance constraint is achieved under the working condition of time-varying inertial parameters, and the dynamic adjustment capacity and anti-interference robustness of an attitude system are remarkably improved.

The invention provides an unmanned surface vessel recursive terminal sliding mode control method based on a novel disturbance observer, and relates to the technical field of unmanned surface vessels. The method comprises the following steps: firstly, designing a fixed time disturbance observer (FTDO) to suppress model uncertainty and adverse effects of external disturbance; and then an adaptive fixed time disturbance observer (AFTDO) is developed, and the adaptive law does not need lumped disturbance priori knowledge. Different from an existing fast non-singular terminal sliding mode surface (FNTSMs) which adopts a linear sliding mode (LSM) to avoid singularity, the method innovatively constructs a recursive terminal sliding mode surface (RTSM), thoroughly avoids singularity through a recursive structure, and remarkably improves convergence precision and speed near a balance point at the same time. A fixed-time recursive terminal sliding mode controller (FTRTSMC) is designed based on a lumped disturbance estimated value of the AFTDO, and it is strictly ensured that a trajectory tracking error converges to zero within fixed time (convergence time is irrelevant to an initial state).

The invention discloses a surface-mounted permanent magnet synchronous motor sensorless high-performance sliding-mode control method, and the method comprises the steps: designing an improved self-adaptive terminal sliding-mode switching function for the problem of high-frequency buffeting of a sliding-mode observer caused by the fixed gain design of the switching function; and dynamically adjusting the gain of the switching function according to the sum of the stator current error and the integral thereof under the two-phase static coordinate system so as to suppress high-frequency buffeting and improve the estimation precision. In order to further improve the performance of the position sensorless control system, a reaching law in a sliding mode controller is optimized, a novel composite gain self-adaptive sliding mode reaching law is designed, the reaching law combines a self-adaptive gain term, a nonlinear exponential term and a linear term, the system state is accelerated to approach when being far away from a sliding mode surface, buffeting is reduced when the system state approaches, and the control precision of the position sensorless control system is improved. Therefore, the dynamic response speed and buffeting suppression capability of the control system are balanced.

The invention discloses a quadrotor unmanned aerial vehicle finite time sliding mode attitude control method based on reinforcement learning, and the method comprises the steps: building a quadrotor unmanned aerial vehicle attitude dynamic model considering external disturbance and model uncertainty, and rewriting the quadrotor unmanned aerial vehicle attitude dynamic model into a standard state equation form; a controller nominal item based on a nonsingular integral terminal sliding mode method is designed, an arrival control law item containing a time-varying matrix is designed, and the sum of the arrival control law item and the nominal item is an attitude controller; based on the reinforcement learning principle, an extended Markov decision process is constructed, a corresponding state set, an action set, action implementation mapping, a reward function and the like are designed, and a time-varying matrix is obtained through reinforcement learning training and is set online. According to the method, the dynamic performance and the steady-state performance of the system are effectively improved, and meanwhile high robustness is achieved under turbulence disturbance.

The invention discloses a quadrotor unmanned aerial vehicle trajectory tracking control method, a quadrotor unmanned aerial vehicle and a storage medium, and relates to the technical field of unmanned aerial vehicle control. The method is technically characterized by comprising the following steps: firstly, providing a fast terminal sliding mode disturbance observer for unknown disturbance of a system so as to realize accurate estimation of the disturbance within preset time; then designing a preset time fast terminal sliding mode controller based on disturbance estimation information, and further weakening a buffeting phenomenon of the system by using a saturation function; finally, based on a Lyapunov function method, it is proved that the system can achieve global predetermined time stability; according to the method, predefined time convergence of the trajectory tracking error of the quad-rotor unmanned aerial vehicle under unknown disturbance can be realized, the upper bound of the stabilization time can be randomly preset in a physical limitation range, the rapidity of the system is ensured, buffeting is eliminated, and the stability of the system is improved.

The invention discloses an SPMSM robust speed control method based on an adaptive high-order expansion sliding-mode observer, and the method comprises the following steps: designing and building a third-order LESO system according to a motor mathematical model, and the third-order LESO system is used for outputting an estimated rotating speed actual value, an estimated acceleration and estimated total disturbance; combining a non-singular fast terminal sliding mode algorithm with a disturbance observer, and designing a non-singular fast terminal sliding mode disturbance observer which is used for observing an acceleration state variable of the motor; the acceleration state variable is input into the third-order LESO system and replaces the estimated acceleration, and a high-order expansion sliding mode observer is generated; and constructing an active-disturbance-rejection controller by using the high-order expansion sliding-mode observer, linear state error feedback and total disturbance compensation, and performing speed control on the motor by using the active-disturbance-rejection controller. According to the method, high-precision observation of disturbance can be realized under the conditions that only less interference information exists and the method is not sensitive to interference frequency change.

The invention discloses a time-varying state constraint terminal sliding mode tracking control method based on an adaptive network, and relates to the technical field of adaptive control, and the method comprises the steps: 1, constructing a constraint potential energy error for each actual state of an engineering controlled object; 2, constructing a composite sliding mode variable with a fixed rational index; all sliding mode variables of all actual states of the project controlled object form an integral sliding mode surface on a vector level; and 3, carrying out online approximation on the actual dynamic state of the engineering controlled object by utilizing the single-hidden-layer radial basis network, and introducing network output as a dynamic compensation item into control input, thereby ensuring that the whole sliding mode surface is driven to zero within finite time and synchronously completing real-time compensation on the actual state of the engineering controlled object. According to the invention, the finite time high-precision tracking control of the controlled object of the controlled project with unknown nonlinearity and double-side time-varying boundaries is realized.

The invention provides a permanent magnet synchronous motor sliding mode control method and system based on disturbance compensation, and the method comprises the steps: constructing a first motor state equation based on a permanent magnet synchronous motor mathematical model containing disturbance; secondly, on the basis of a sliding mode control theory, a novel adaptive reaching law and a non-singular fast terminal sliding mode surface are constructed, stability proving is completed, and the fast convergence capability is analyzed; designing a novel speed ring controller through the state equation, the reaching law and the sliding mode surface; designing a sliding mode disturbance observer for a disturbance part in the speed loop controller; and finally, carrying out FOC speed regulation control on the permanent magnet synchronous motor by using the designed speed ring controller and the disturbance observer. Compared with an existing well-known sliding mode control scheme, the hybrid control method of the speed loop controller and the sliding mode disturbance observer is adopted, system buffeting is effectively weakened, meanwhile, the dynamic response speed is considered, and the system robustness is improved.

The invention provides an anti-disturbance unmanned aerial vehicle trajectory tracking control method, system and device and a medium. The method comprises the following steps: establishing a six-degree-of-freedom rigid body dynamic model of a four-rotor unmanned aerial vehicle; selecting an unmanned aerial vehicle feasible trajectory of the kinetic model as an expected trajectory, and introducing a coupling attitude; designing a position loop control law, generating a virtual control force based on a smooth terminal sliding mode control surface, and calculating an actual thrust; designing an attitude loop control law, representing an attitude error based on Lie group SO (3), constructing an attitude tracking controller with a stable global index, and outputting a control torque; constructing a four-order state observer to estimate the angular velocity and the angular acceleration of the coupling attitude, and replacing a true value with an estimated value to participate in control law calculation; thrust and control torque are converted into thrust input of the unmanned aerial vehicle, the unmanned aerial vehicle is driven to track an expected trajectory, and the problems that in trajectory tracking control of the four-rotor unmanned aerial vehicle, dependence on position acceleration measurement is high, noise is amplified through differential derivation, disturbance rejection is weak, and real-time calculation burden is large are solved.

The invention discloses an improved sliding-mode active-disturbance-rejection control method for a network construction type photovoltaic hybrid energy storage converter, and provides an improved sliding-mode active-disturbance-rejection control strategy based on a quasi-continuous algorithm on the basis of a virtual synchronous generator (VSG) technology, the VSG is often matched with a voltage and current double-closed-loop strategy, a voltage outer loop adopts PI control, a reference value is provided for a current inner loop, and the current inner loop adopts PI control. A high-order super-spiral sliding mode observer (HO-STSMO) is adopted in a current inner ring, so that the response speed and the tracking precision are better; meanwhile, a double-sliding-mode switching control law form is adopted, a quasi-continuous integral terminal sliding mode controller (QC-ITSMC) is introduced, and an improved index reaching law is designed to smooth a system control signal and improve the robustness of the system; according to the control method, power grid power fluctuation is effectively suppressed, the performance of the photovoltaic hybrid energy storage converter is improved, the bus voltage is kept stable, and the system operation stability is improved.

The invention relates to a clamping force constraint backstepping sliding mode control method for an electronic mechanical braking system, and belongs to the related technical field of new energy automobile control. The method comprises the following steps of: establishing a state space model of the system by considering the nonlinear characteristic of the electronic mechanical braking system, and reasonably simplifying the state space model into a strict feedback form; a time-varying tangent barrier Lyapunov function (BLF) containing an error integral term is constructed, an exponentially decayed time-varying function is used as a constraint boundary of a clamping force tracking error, the integral term is introduced to eliminate a steady-state error caused by unmodeled dynamics, and the output constraint performance and tracking precision of a system are ensured; on the basis, a control law is designed by combining a backstepping method and non-singular fast terminal sliding mode control, and fast and accurate tracking of the braking clamping force is achieved; and proving the system stability based on the Lyapunov stability theorem. According to the invention, the braking response time and the clamping force control precision of the electronic mechanical braking system can be effectively improved.

The invention relates to the technical field of permanent magnet synchronous motors, and particularly discloses a permanent magnet synchronous motor low-buffeting terminal sliding mode control method based on adaptive disturbance compensation, comprising the following steps: S01, redefining a motor rotational inertia mathematical model; s02, improving a traditional nonsingular fast terminal sliding mode surface based on nonlinear system representation, and constructing a novel dynamic gain nonsingular fast terminal sliding mode surface; s03, performing derivation on the novel dynamic gain nonsingular fast terminal sliding mode surface, and combining a derivation function with nonlinear system representation to obtain an equivalent control law ieq; and S04, adopting an exponential reaching law isw as a switching control law of the sliding mode controller, and obtaining a novel different fast terminal sliding mode controller model according to an equivalent control principle in combination with the equivalent control law ieq and the exponential reaching law isw. The invention aims to improve the tracking response speed of a position instruction during servo control of the permanent magnet synchronous motor.

The invention relates to an automobile finite time path tracking fault-tolerant control method considering steering actuator faults. The method comprises the following steps: firstly, establishing a vehicle dynamics model and a steering execution mechanism dynamics model, designing a path tracking control strategy by applying a model prediction control method, and establishing an upper-layer path tracking controller; then, on the basis of a differential driving auxiliary steering principle, a preset performance control method of finite time convergence and a nonsingular fast terminal sliding mode control theory are combined, and a steering actuator fault-tolerant controller is established; and finally, designing a torque distribution controller by adopting an optimal control theory, and solving an optimal four-wheel driving torque control quantity through quadratic programming. According to the method, the influence caused by the failure of the steering actuator can be effectively compensated, the safety and the stability of the vehicle are remarkably improved, and a feasible solution is provided for the fault-tolerant control of the steering actuator in a future intelligent vehicle path tracking scene.

The invention discloses a quadrotor unmanned aerial vehicle attitude fault-tolerant control method. The method comprises the following steps: S1, establishing a tracking error dynamic model of a quadrotor unmanned aerial vehicle attitude system; s2, designing a reduced-order fixed-time expansion state observer; s3, constructing an adaptive preset performance function; s4, designing a fast nonsingular terminal sliding mode surface and a fixed time reaching law based on an adaptive preset performance function and the lumped disturbance estimated value, and generating a posture virtual control quantity; and S5, according to the mapping relation between the attitude virtual control quantity and the attitude loop control moment, performing inverse solution to obtain the attitude loop control moment, and inputting the control moment into an attitude actuator to enable the attitude angle tracking error to converge to be near a balance point within a fixed time. Compared with the prior art, the four-rotor unmanned aerial vehicle attitude fault-tolerant control method has the advantages that strict constraint on attitude system response under the actuator fault condition is provided, it is ensured that unmanned aerial vehicle tracking errors meet preset transient state and steady state performance constraints, and meanwhile the vulnerability problem of preset performance is effectively avoided.

The invention provides a six-rotor unmanned aerial vehicle position-attitude layered composite adaptive sliding-mode control method, which comprises the steps of introducing a terminal sliding-mode robust controller into a position loop to realize finite time convergence of a system state, and performing real-time compensation on unknown disturbance and modeling uncertainty through a sliding-mode adaptive rate. The quick response and anti-interference capability of a complex track are improved; superspiral sliding mode control is adopted in an attitude ring, sliding mode gain is adjusted in real time through an adaptive law, a controller is made to automatically match flight state changes, and attitude stability and robustness are enhanced; and meanwhile, a position signal output by the position controller is converted into a specific attitude angle reference by utilizing an attitude resolving module, so that hierarchical cooperative control of the position and the attitude is realized. Compared with traditional PID and SMC controllers, the method is faster in convergence and higher in tracking precision, has stronger adaptivity and robustness to external disturbance and parameter uncertainty, and can significantly improve the motion control performance of the six-rotor unmanned aerial vehicle in complex environments and tasks.

The application discloses a quad-rotor unmanned aerial vehicle attitude fault-tolerant control method considering unknown wind disturbance, and relates to the field of unmanned aerial vehicle attitude control design; the method can effectively cope with unknown wind disturbance, actuator partial failure and deviation faults. In the application, unknown wind disturbance and deviation faults are regarded as total disturbance, an improved disturbance compensator is designed by using an adaptive mechanism for the total disturbance, and the size of switching gain is adjusted online according to the control accuracy requirement, so that the waste of controller output energy caused by excessively large switching gain is avoided. For actuator partial failure, a failure factor compensator designed based on an adaptive method enables the unmanned aerial vehicle to timely process faults and recover normal trajectory. An attitude controller is designed by using a non-singular fast terminal sliding mode control technology, so that the robustness and fast response characteristics are ensured, the unmanned aerial vehicle can timely process faults, the fault tolerance of the unmanned aerial vehicle is enhanced, and the flight safety of the unmanned aerial vehicle is improved.

The invention discloses a cantilever beam vibration control method based on rapid nonsingular terminal composite sliding mode control, and belongs to the field of vibration control. The method comprises the following steps: firstly, constructing a kinetic model of a piezoelectric cantilever beam, and establishing a state-space equation; then, according to a state-space equation of the piezoelectric cantilever beam, constructing an extended state observer, and obtaining estimated values of internal and external total disturbance, a displacement tracking error and a speed tracking error of the vibration control system; and finally, based on the internal and external total disturbance, displacement tracking error and speed tracking error of the vibration control system estimated by the extended state observer, constructing a rapid nonsingular terminal composite sliding mode controller, and using the controller to control a piezoelectric actuator on the piezoelectric cantilever beam. A convergence factor of a high-order exponential term is introduced into a nonsingular terminal sliding mode surface, so that a displacement tracking error and a speed tracking error of a vibration control system can be converged to zero within finite time, the problem of low convergence speed is solved, and meanwhile, the chattering phenomenon in the sliding mode control process is reduced.

The invention discloses an under-actuated unmanned surface vehicle finite time trajectory tracking sliding mode control method based on a filter, and relates to the technical field of unmanned surface vehicle control. In order to solve the technical problems in the prior art that the control design under an under-actuated structure is limited and full-state trajectory tracking is difficult to realize, the technical scheme provided by the invention is as follows: constructing kinematics and dynamics models of the under-actuated unmanned ship; performing coordinate transformation on the model, and introducing a transformation coefficient to transform an original under-actuated model into a control model with a regular form; based on the conversion model, a finite time disturbance observer is constructed, the input is system state deviation, and the output is a disturbance estimation value; the system error is used as input, a sliding mode surface with terminal sliding mode characteristics is constructed, and a smooth sliding mode variable is output; the disturbance estimation value and the sliding mode variable serve as input, a finite time sliding mode controller is designed, and a control instruction of the unmanned ship is output; the unmanned ship can rapidly and stably track the preset trajectory in a complex disturbance environment.

The invention provides a Markov jump-based mechanical arm preset time trajectory tracking control method, which comprises the following steps of: calculating a trajectory tracking error by establishing a two-degree-of-freedom mechanical arm dynamic model with a Markov jump characteristic; a trajectory tracking error is subjected to nonlinear transformation, a nonsingular terminal sliding mode surface is constructed in combination with a preset convergence time upper limit function, and then a control torque is synthesized through an equivalent control item and a robust switching item containing a sliding mode surface sign function and a switching gain to drive a mechanical arm. And the trajectory tracking error is difficult to converge in the preset time.

The invention particularly relates to a four-rotor unmanned aerial vehicle trajectory tracking anti-interference control method and system. The four-rotor unmanned aerial vehicle trajectory tracking anti-interference control method comprises the following steps: establishing a four-rotor unmanned aerial vehicle double-loop control framework and a kinetic model, solving an error amount of a preset performance characteristic, constructing an extended state observer, regarding disturbance as a system state, estimating system uncertainty and external disturbance on line, and generating a compensation amount; a sliding mode controller is designed by taking sliding mode control as a core and combining an extended state observer, a preset performance error amount, a non-singular fast terminal sliding mode surface and an approaching rate, and high-precision trajectory tracking and anti-interference control are realized. According to the four-rotor unmanned aerial vehicle trajectory tracking anti-interference control method and system, high-precision trajectory tracking is achieved, the problem of collision or out-of-control caused by too large position errors can be remarkably reduced, the robustness to complex interference such as sudden change wind speed is remarkably improved, and the dynamic response time is shortened; and the method has low requirements on boundary conditions and is suitable for various small four-rotor unmanned aerial vehicles.

The invention belongs to the technical field of laser radar scanning control, and discloses an MEMS galvanometer scanning method and system based on integral terminal sliding mode control, and the method comprises the steps: constructing an integral terminal sliding mode surface, introducing a minimum operator reaching law, enabling a system state to be converged to the sliding mode surface in a finite step, and enabling the system state to be converged to the sliding mode surface; the tracking error reaches the preset bandwidth within the limited step, high-precision trajectory tracking can still be achieved even under the large-angle and high-speed scanning working condition, and the edge is not obviously distorted. Besides, according to the method, external disturbance is estimated and compensated in real time through the disturbance observer so as to reduce gain needed by switching items in sliding mode control, sudden disturbance and periodic disturbance are estimated and dynamically compensated on line through the disturbance observer, and therefore small steady-state errors and phase stability are maintained. In complex scenes such as composite disturbance, the control method can significantly improve the scanning precision and stability of the MEMS galvanometer.

The invention discloses a permanent magnet synchronous linear motor self-adaptive fuzzy terminal sliding mode control system, a self-adaptive fuzzy terminal sliding mode controller further comprises a switching control law module, the switching control law module outputs a self-adaptive fuzzy switching control law, and the self-adaptive fuzzy switching control law comprises a switching gain, an adaptive fuzzy terminal sliding mode, an adaptive fuzzy terminal sliding mode and an adaptive fuzzy terminal sliding mode. The corresponding switching gain is adjusted along with the change of the sliding mode surface, and the convergence speed corresponding to the position difference and the speed difference is controlled within the finite time; according to the method, better dynamic performance is provided, and singularity points can be eliminated while the convergence speed of the system is ensured; fuzzy control and sliding mode control are combined, and the chattering phenomenon generated by sliding mode control is restrained. Through fusion of adaptive control and fuzzy nonsingular fast terminal sliding mode control, parameters are optimized and adjusted in real time, and robustness is enhanced, so that control precision is improved, influence of unknown external disturbance is reduced, and uncertainty generated by load change is reduced.

The invention discloses a mechanical arm residual vibration control method and device based on a non-singular fast terminal sliding mode, equipment, a medium and a product, and relates to the field of industrial robot motion control. A non-singular sliding mode surface and a control law are constructed by taking a position error and a speed error between displacement of residual vibration at the tail end of the flexible part of the mechanical arm and a preset track as input, a non-singular fast terminal sliding mode controller is determined based on the non-singular sliding mode surface and the control law, the residual vibration acceleration at the tail end of the flexible part is collected, and the position error and the speed error of the residual vibration are determined; inputting the position error and the speed error into the optimized non-singular fast terminal sliding mode controller to obtain a residual vibration control law; solving joint driving angles of the first arm and the second arm of the mechanical arm according to the residual vibration control law and the mechanical arm kinematic model, and controlling the mechanical arm to move based on the joint driving angles. The residual vibration of the mechanical arm can be effectively restrained, and the control precision is improved.

To address the problem of low posture control accuracy in underwater robot systems due to strong nonlinearity, high coupling, and internal parameter uncertainty, this paper proposes a novel non-singular fast terminal sliding mode control method with finite-time convergence. First, the existing dynamic equations of the underwater robot are given and transformed into trajectory tracking error equations to facilitate the application of the sliding mode control method. Then, a non-singular fast terminal sliding mode surface and its corresponding controller are proposed. The controller is analyzed and verified to effectively avoid singularity problems. Simulations are performed on a six-degree-of-freedom underwater robot as the control object, and its posture control is compared with a typical non-singular fast terminal sliding mode control method. The simulation results show that this method can converge the posture to the target posture within a finite time, with higher relative convergence accuracy, and effectively suppresses the effects of internal parameter uncertainty and external interference in the underwater robot system.

The invention discloses an underwater manipulator trajectory tracking finite time sliding mode controller design method, a sliding mode controller and a control system, and belongs to the technical field of underwater robot control. Comprising the steps that a nonsingular terminal sliding mode surface control framework is constructed, the framework fuses factors such as system model uncertainty, external disturbance, output constraint and input saturation, and a foundation is laid for accurate control; in order to ensure that a system state is always in a time-varying constraint boundary in a complex marine environment, a time-varying barrier Lyapunov function is combined with sliding mode control, tracking error constraint is converted into sliding mode surface constraint through mathematical conversion, and effective constraint on the system state is realized through strict derivation and analysis; besides, a finite time auxiliary control system with a dynamic compensation strategy is designed for the problem of input saturation caused by physical limitation of the actuator, trajectory errors can be rapidly restrained, and the accuracy and stability of trajectory tracking of the underwater manipulator are remarkably improved.

The invention relates to a trajectory tracking control method and system based on a predefined time observer and a neural network. The method comprises the following steps: defining a trajectory tracking error and deriving to obtain an error derivative; constructing a predefined time observer, estimating a state and composite disturbance which cannot be directly measured by the controlled system, and converging an observation error within a preset time to obtain a state estimation result; constructing a non-singular fast terminal sliding mode variable; carrying out online approximation by adopting a neural network, updating the weight of the neural network in real time based on the sliding mode variable, and outputting a compensation item through the neural network; and combining the state estimation result, the sliding mode variable and the compensation item to construct a trajectory tracking control law, and applying the trajectory tracking control law to a controlled system, so that a trajectory tracking error is converged to zero or a preset neighborhood within a preset time. The stable convergence of the trajectory tracking error within the predefined time can be realized, and the dynamic response performance and the tracking precision of the system are improved.

The invention discloses a linear drive continuous mechanical arm fixed time impedance control method based on a non-singular fast terminal sliding mode, and the method comprises the steps: firstly, building a dynamic model of a linear drive continuous mechanical arm; secondly, designing an impedance model based on expected inertia, damping and rigidity, and representing an impedance error; and finally, a linear drive continuous type mechanical arm fixed time impedance control system is designed, the control system comprises a fixed time disturbance observer for estimating external unknown disturbance and unmodeled dynamics and a singular avoiding piecewise function for eliminating control law singularity, and an impedance control law is designed through a non-singular fast terminal sliding mode method. The linear drive continuous mechanical arm can achieve stable transition between free motion and a contact environment, and has high-precision and high-robustness compliant control capacity.