20 results about "Underwater manipulator" patented technology

The invention provides an underwater manipulator motion balance real-time monitoring method based on acoustic sensing, which comprises the following steps: if a frequency shift range exceeds a preset range threshold, filtering a signal data set, and separating superposed components of a friction sound signal and a water flow interference sound to obtain a preliminarily separated friction sound signal; performing short-time Fourier transform processing on the preliminarily separated friction sound signals, extracting time-frequency features of the friction sound signals, and obtaining a friction sound feature set; calculating the signal energy ratio of the friction sound signal to the water flow interference sound by analyzing the frequency spectrum difference between the friction sound feature set and the water flow interference sound, screening the interference sound according to the signal energy ratio, and rejecting the screened interference sound to obtain a separation signal; and when it is recognized that the manipulator executes the complex track task, track complexity is recognized, the position of the acoustic sensor array is dynamically adjusted according to the track complexity, the dynamic layout of the acoustic sensor array is optimized, and array configuration is obtained.

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 discloses an underwater mechanical arm shake compensation control method based on sensor space-time heterogeneous matching. The method comprises the steps that firstly, an eye-in-hand camera at the tail end of a mechanical arm is used for estimating shaking of a mechanical arm base; meanwhile, an inertial measurement unit is used for directly measuring shaking of the mechanical arm base; fusing and optimally estimating two paths of shake measurement data by adopting a multi-sensor space-time heterogeneous matching algorithm based on Kalman filtering and a cross-correlation method; and finally, the joint control quantity of the mechanical arm is obtained through inverse kinematics calculation, so that rotation shaking of a mechanical arm base is effectively compensated, and the stability of the tail end posture of the mechanical arm is kept. According to the method, the problems that the control precision is damaged and the operation reliability is reduced due to shaking of the base in the operation process of a mobile platform mechanical arm, especially an underwater vehicle-mechanical arm system are solved, the method can be combined with a visual servo system or a teleoperation mechanical arm control system, and the operation reliability and practicability are improved.

The application discloses an underwater serial-parallel hybrid manipulator with motion redundancy, comprising an end effector, a two-degree-of-freedom 2R serial mechanism, a six-degree-of-freedom 2-RRRPRS-RRRPRRU motion-redundant parallel mechanism and a base mounting rack; the serial-parallel hybrid mechanism improves the motion accuracy, structural stiffness and reliability of the underwater manipulator while ensuring sufficient working space. The motion-redundant design is realized by adopting a planar five-link two-degree-of-freedom mechanism and a swing rod, and the parallel mechanism can avoid singular configurations through coordinated control of multiple driving elements in a branch. The motion-redundant design can avoid singular configurations of the parallel mechanism, expand the working space of the parallel mechanism, improve the motion performance of the underwater manipulator, increase the dexterity of the mechanism and improve the structural stiffness and load-carrying capacity of the mechanism, so that the underwater manipulator can better adapt to the complex and changeable working environment underwater.

A sealing structure of an underwater mechanical arm is characterized by comprising a mounting plate and a protective pipe, one end of the protective pipe is welded and fixed to the mounting plate, the mechanical arm extends into the protective pipe, a bearing is arranged outside the mechanical arm, the bearing is mounted in the protective pipe, and the protective pipe is fixedly connected with the mechanical arm. A connecting thread is arranged on the inner wall of a port of the other end of the protection pipe and is in threaded connection with the sealing end cover, a center through hole is formed in the center of the sealing end cover, and the hole diameter of the center through hole is matched with the outer diameter of the mechanical arm, so that the mechanical arm penetrates through the center through hole of the sealing end cover; the mechanical arm is isolated from water through the protection pipe, so that the corrosion damage condition of the mechanical arm is reduced, the sealing end cover is fixed to the end opening of the protection pipe in a threaded installation mode, water is prevented from entering the end opening, and the mechanical arm is prevented from being damaged. And the sealing assembly is designed to enhance the sealing performance of the joint of the sealing end cover and the mechanical arm.

This invention belongs to the field of underwater manipulator reliability analysis technology, and discloses a non-probabilistic reliability analysis method for underwater manipulators considering fluid-structure interaction effects. The method includes the following steps: quantifying the uncertainty of fluid load parameters under finite sample conditions using a non-probabilistic interval method; updating sample points based on Bayesian theory, and obtaining the relationship between interval parameters and reliability through analytical solutions; conducting strength and stability analysis of underwater manipulator components using the buckling stability criterion as the failure criterion to obtain the critical buckling load; performing uncertainty propagation analysis using the Taylor series expansion method to solve for the structural response interval corresponding to the non-probabilistic interval of the input uncertainty parameters; and comparing the response interval with the limit state equation using stress-strength interference theory or tolerance interference theory to establish a non-probabilistic Bayesian reliable reliability analysis model, suitable for reliability assessment of underwater manipulator components under small sample conditions.

The invention discloses an underwater mechanical arm tracking control system and method based on a double-loop zero neural network, and the method comprises the following steps: obtaining parameters of an underwater mechanical arm, and obtaining an expected trajectory vector of an end effector; a controller set in a vector form is obtained by combining a double-loop zero neural network method with an underwater mechanical arm system equation, and a control task is decoupled into outer-loop kinematics planning and inner-loop dynamics compensation through the controller set; and a control torque vector used for driving the mechanical arm is set according to the controller set, so that a trajectory vector of an end effector of the mechanical arm is quickly converged to an expected trajectory vector.

This invention discloses a control method for an underwater electro-manipulator based on model predictive control. The method includes: establishing a nonlinear dynamic model of the underwater electro-manipulator; establishing a predictive model of the underwater electro-manipulator using model predictive control; inputting the angular displacement and angular velocity of each joint of the underwater electro-manipulator into the predictive model in real time, and outputting the driving torque of each joint of the underwater electro-manipulator in real time, thereby controlling the continuous operation of the underwater electro-manipulator and realizing real-time control of the underwater electro-manipulator. This invention improves the control accuracy of the manipulator in underwater scenarios by utilizing model predictive control. It can promptly compensate for model mismatch when dealing with time-varying disturbances, thus exhibiting good robustness for nonlinear underwater manipulator systems under actual constraints such as torque, angular velocity, and angular acceleration. Specifically, it achieves relatively smooth control output at the procedural level under underwater transient disturbances, demonstrating good anti-disturbance performance.

This invention discloses a shared control method for remote operation of an underwater robotic arm based on vision-assisted alignment. The method includes the following steps: First, constructing a transformation matrix between the base coordinate system, the end effector coordinate system, and the camera coordinate system; then, acquiring the remote operation command and the target image collected by the visual servo system, calculating the tracking error between the current image feature point position of the target object and the desired position of the target object in the pixel coordinate system in the remote operation command; next, minimizing the tracking error using the BLF image feature point velocity control law, thereby calculating the image feature point velocity; finally, calculating the desired joint angular velocity using a joint angle control law based on the null projection method, and thus controlling the movement of the underwater robotic arm. This invention solves the operational difficulties caused by the lack of depth information, target loss, and limited degrees of freedom in remote operation of robotic arms, effectively reducing the cognitive load on operators and improving the alignment accuracy and execution efficiency of robotic arm operations.

The application relates to an underwater mechanical arm operation system based on a large folding configuration and relates to the technical field of underwater robots. The application solves the problems that the existing boat-mounted mechanical arm is difficult to simultaneously satisfy the arrangement constraint and the operation space constraint of the boat-mounted mechanical arm, the operation capacity and the arrangement capacity have technical contradictions, and the underwater sealing technology of a general robot joint is deficient. The connecting support base, the first joint driving sealing unit, the second joint driving sealing unit, the large arm unit, the third joint driving sealing unit, the fourth joint driving sealing unit, the small arm unit, the fifth joint driving sealing unit, the sixth joint driving sealing unit and the mechanical arm terminal connecting plate are sequentially connected from front to back, and the mechanical hand sealing driving unit, the visual sealing unit and the operation mechanical hand are respectively installed on the mechanical arm terminal connecting plate. The application is used for developing the large folding configuration underwater mechanical arm, the underwater electric driving sealing unit and the underwater sensing unit.

The invention relates to the technical field of motion planning and control of underwater mechanical arms, in particular to a harmonic-wave-oriented active-disturbance-rejection motion control method of an underwater mechanical arm. Comprising the following steps: establishing an underwater mechanical arm kinematics model; constructing a harmonic noise mathematical expression and a harmonic signal mathematical expression according to the harmonic noise frequency measured by the measuring tool, and designing a noise compensator capable of adaptively generating harmonic signals; according to the noise compensator capable of adaptively generating the harmonic signals, combining an underwater mechanical arm kinematics model, and adding error feedback into a kinematics scheme at the same time, designing an underwater mechanical arm active-disturbance-rejection motion control method for harmonic waves; and the lower computer controller drives each joint and tracks a target trajectory according to a calculation result of the harmonic-wave-oriented underwater mechanical arm active-disturbance-rejection motion control method, and controls the underwater mechanical arm to complete a given tail end operation task. According to the method, harmonic noise can be effectively handled, and the anti-interference capability and the control precision of the underwater mechanical arm are improved.

The invention belongs to the technical field of industrial machinery, and particularly relates to an underwater manipulator compliance control method based on dynamic characteristics of oil-filled joints, which comprises the following steps of: receiving a motion instruction and a parameter configuration instruction from an upper computer, and analyzing to obtain a target position, a maximum speed and a compliance control parameter of each joint; calculating the interpolation target position and the interpolation target speed of each joint in the next control period through an online trapezoidal trajectory planner; actual positions and actual speeds fed back by the joint encoders are obtained, and then position errors and speed errors are obtained; inputting the torque into a provincial simplified impedance controller, and calculating to obtain an initial output torque; combining the calculated integral compensation amount, the friction compensation amount and the initial output torque to obtain a comprehensive output torque, converting the comprehensive output torque into a target current value, and organizing the target current value into an RPDO data frame; and the RPDO data frames are periodically sent to the corresponding joint drivers through the CAN bus interface so as to control the motor to move. According to the method, a more simplified trajectory planning method is used, and the pressure on an operation platform is smaller.

The application provides a method for predicting water dynamic moment of an underwater mechanical arm, which can be applied to the technical field of underwater robots. The method comprises the following steps: for the i-th section of the underwater mechanical arm, an initial water dynamic moment model of the i-th section is constructed based on flow parameters, mechanical arm parameters, dimensionless resistance coefficients and added mass coefficients, the underwater mechanical arm is evenly divided into N sections along the axial direction, i is an integer greater than or equal to 1 and less than or equal to N; the initial water dynamic moment model of the i-th section is converted into a linear model of the i-th section based on the correlation between the dimensionless stroke ratio and the dimensionless resistance coefficient and the added mass coefficient; the water dynamic coefficients in the linear model of each of the N sections are decoupled by using a least square algorithm, and a coefficient discrete sample set is obtained; the coefficient discrete sample set is spline fitted by using a least square algorithm based on a residual vector, and a target coefficient curve is obtained, so that the water dynamic moment of the underwater mechanical arm can be predicted by using the target coefficient curve.

The application relates to a kind of joint space limited synchronous control method and equipment of underwater double-arm manipulator, method includes the following steps: using D-H parameter method respectively to two underwater manipulators modeling, based on the physical limit of manipulator joint, for the synchronous planning problem of underwater manipulator under the condition of space limitation, construct time-varying nonlinear equation with constraint condition;Based on time-varying nonlinear equation, by introducing non-negative time-varying vector, construct time-varying synchronous planning model based on pseudo-inverse description using neural dynamics design formula;For time-varying synchronous planning model, discrete processing is carried out using difference formula, and discrete synchronous planning model is obtained;The synchronous control of underwater double-arm manipulator is carried out using discrete synchronous planning model.Compared with prior art, the underwater double-arm manipulator can still accurately complete a specific synchronous planning task under the condition of joint motion space limitation, and the synchronous planning precision of underwater double-arm manipulator in practical application can be improved.

This invention relates to the field of underwater robotic arm control technology, specifically to a method and system for trajectory planning and control of an underwater robotic arm based on the PNVRGZND model. The method includes: obtaining the joint angle vectors, desired velocity vectors, and Jacobian matrix of a six-DOF cascaded underwater robotic arm; transforming the kinematic equations into time-varying linear equations and defining an error function; constructing a PNVRGZND model containing a novel double-integral structure, novel time-varying parameters that are monotonically increasing and bounded, and a novel nonlinear activation function containing exponential, linear, and power terms; substituting the derivative of the error function into the PNVRGZND model to obtain the dynamic evolution equation of the joint angular velocity vector; determining known quantities based on the real-time state of the robotic arm and the desired trajectory; numerically solving the dynamic evolution equation to obtain the joint angular velocity vector and outputting it to the joint actuator. This invention significantly improves the trajectory tracking accuracy and robustness of underwater robotic arms in environments with strong interference.

The application relates to the technical field of underwater mechanical arms, in particular to a method for compensating the tail end of an underwater mechanical arm based on a Gaussian process, which successfully establishes a model for the deviation distance of an end effector in underwater space control of the end effector by means of the Gaussian process, reduces a large number of correction points collected compared with the method adopting DART or (HG-) Dagger in the prior art, alleviates the long calculation time and low work efficiency existing in the prior art, and improves the underwater work reliability of the mechanical arm.

The application discloses a kind of underwater mechanical arm shake compensation control methods based on sensor space-time heterogeneous matching.The method comprises: first, the eye in hand camera of mechanical arm tail end is used to realize the estimation of mechanical arm base shake;While using inertial measurement unit to directly measure the mechanical arm base shake;Then, the multi-sensor space-time heterogeneous matching algorithm based on Kalman filtering and cross-correlation method is used to realize the fusion and optimal estimation of two-way shake measurement data;Finally, the joint control amount of mechanical arm is obtained through inverse kinematics solution, so as to effectively compensate the rotational shake of mechanical arm base and maintain the stability of mechanical arm tail end posture.The method solves the problem that the control accuracy may be damaged and the operation reliability may be reduced due to base shake during the operation of mobile platform mechanical arm, especially underwater vehicle-mechanical arm system, and can be combined with visual servo system or remote operation mechanical arm control system to improve the reliability and practicability of operation.

The invention particularly relates to an analog simulation method for an underwater manipulator dynamics cooperative grabbing task, and belongs to the technical field of unmanned underwater platform autonomous operation control. According to the method, the dynamic interaction between an underwater carrier platform and a multi-degree-of-freedom mechanical arm is accurately described by constructing a coupling dynamic model comprising the underwater carrier platform and the multi-degree-of-freedom mechanical arm. Based on the model, a hierarchical priority control strategy is designed, firstly, accurate position tracking of the tail end of the mechanical arm is guaranteed, secondly, the platform posture is kept stable, and disturbance of movement of the mechanical arm to the platform is compensated through reactive force feedforward. By means of MATLAB / OCTAVE software, full-task process simulation and visual dynamic display from platform approaching, accurate positioning, mechanical arm unfolding, target grabbing to system recycling are achieved through the method. According to the invention, an efficient and low-cost offline verification and parameter debugging platform is provided for collaborative operation of an underwater robot-manipulator system, and the risk and cost of an actual underwater experiment are effectively reduced.

The invention relates to the technical field of mechanical arm design, and particularly discloses an underwater mechanical arm and underwater operation equipment comprising the underwater mechanical arm. The underwater mechanical arm comprises a main driving mechanism, a transmission mechanism is arranged below one side of the main driving mechanism, and a protective continuous rotating mechanism is arranged on the outer surface of the transmission mechanism; a clamping mechanism is arranged at the end, away from the main driving mechanism, of the transmission mechanism, protection mechanisms are arranged at the lower end of the main driving mechanism and on the outer surface of the protection connecting rotary shaft, the main driving mechanism and the transmission mechanism are linked to simplify driving logic and reduce the failure rate, and switching of multiple transmission paths through a single motor is achieved in the main driving mechanism. Traditional multi-joint independent driving is replaced, a transmission primary rod, a transmission transfer rod and a tail end rod form graded transmission, power is transmitted in cooperation with meshing of a conical tooth groove and a bevel gear, due to the fact that driving parts are concentrated, the sealing pressure of a driving system under the underwater high-pressure environment is reduced, and the problems that a traditional mechanical arm is complex in structure and high in failure rate due to multiple driving parts are solved.

The invention provides a self-adaptive control method and device for an underwater mechanical arm, and relates to the technical field of reinforcement learning. Inputting the current state and the target motion trail into the trained adaptive control model to obtain a first control parameter output by the trained adaptive control model; the first control parameter comprises a first control torque and a first angular velocity direction; wherein the trained adaptive control model is constructed on the basis of a Q-learning algorithm; and finally, based on the first control parameter, the underwater mechanical arm is controlled to perform tracking motion on the target motion trail, and a target tracking result is obtained. According to the self-adaptive control method for the underwater mechanical arm, when the mechanical arm moves in the underwater environment, the target movement track can be accurately tracked, and the control precision and robustness of the underwater mechanical arm are improved.