331results about How to "Suppress chatter" patented technology

The invention discloses a mechanical arm trajectory tracking control method based on a high-order sliding-mode observer. The method comprises the following steps of 1, establishing a dynamical model of an n-degree-of-freedom rotary joint rigid mechanical arm system; 2, acquiring measurement information of joint angles q of a mechanical arm by utilizing a photoelectric encoder, and calculating a mechanical arm trajectory tracking error e = q - qd according to a set expected joint angle qd; 3, establishing a global integral fast terminal sliding mode surface according to e; 4, determining control torque tau of joint driving motors of the mechanical arm according to the sliding mode surface and establishing a control gain self-adaptive rate capable of being dynamically adjusted; and 5, establishing the output feedback high-order sliding mode observer according to the control torque tau and the joint angles q of the mechanical arm, and estimating current angular velocity of joints and lumped disturbance. According to the method, under the situation that nonlinear uncertain items such as system parameter perturbation, external torque interference and damping friction exist in the mechanical arm system, the trajectory tracking control of the mechanical arm is realized only based on the measurement information of all the joint angles, and robustness of whole control process is ensured.

The invention discloses an adaptive terminal sliding-mode controller based mechanical arm trajectory tracking control method. The method includes the following steps: 1, establishing a rigid mechanical arm system dynamics model having n degrees of freedom rotating joints; 2, obtaining the measuring information of each joint angle q and angular velocity which is shown in the description of a mechanical arm through a photoelectric encoder, setting the expected angle q<d> and expected angular velocity which is shown in the description tracked by each joint, and calculating mechanical arm trajectory tracking errors [epsilon]1 = q - q<d> and the first derivative shown in the description of trajectory tracking error versus time; 3, establishing a novel non-singular terminal sliding-mode surface s according to the [epsilon]1 and [epsilon]2; and 4, designing the controlling moment tau of the driving motor of each joint of the mechanical arm according to the sliding-mode surface s, and establishing an adaptive rate which can adjust control gain to dynamically estimate system lumped disturbance upper bound. Under the circumstance that internal and external interference such as parameter perturbation and torque disturbance existing in the mechanical arm system, the method can perform real-time feedback so as to realize the accurate controlling of mechanical arm trajectory tracking based on the measuring information of each joint angle and angular velocity, and the controlling on the robustness of the whole course can be guaranteed.

A vibration suppressing method and a vibration suppressing device are disclosed. After detection of chatter vibration using at least one vibration detecting device, a stable rotation speed for suppressing the chatter vibration is calculated using a stable rotation speed calculating device. A determination device then compares a detection value detected by the vibration detecting device, a predetermined setting value, and/or a current value that is calculated based on at least one of the detection value and the setting value, to a predetermined determination reference value that is previously set. Thereafter, the determination device determines whether or not the stable rotation speed is adopted in accordance with the comparison result, and changes rotation speed of the rotary shaft to the stable rotation speed if the stable rotation speed is adopted.

The invention provides an attitude control method of a four-rotor aircraft. Firstly, an error magnitude is calculated from a given instruction attitude angle and a practical attitude angle, then a sliding mode and an approaching law are selected, and a sliding mode attitude control law is designed; in addition, in order to inhibit buffeting caused by sliding mode control, the sliding mode and a first-order differential of the sliding mode are used as input of a fuzzy logic controller, a control gain is used as output of the fuzzy logic controller, in this way, a self-adaptive fuzzy sliding mode attitude control law is designed, and the control gain is adjusted on line through fuzzy rules. A closed-loop system controlled by the method is capable of being stably adjusted to an instruction attitude angle, the robustness and the control precision are good, and an effective means is provided for engineering realization of attitude control of the four-rotor aircraft.

The present invention relates to a method and a device for suppressing vibration generated during machining in a machine tool for performing machining while rotating a tool or a work. A stable rotation speed is acquired by finely changing a rotation speed of a rotary shaft 3 based on an expected stable rotation speed, and calculating an amount of change of a k' number, and the like. Therefore, a more accurate rotation speed can be acquired, and 'chatter vibration' generated during machining can be suppressed more effectively than a conventional method. As a result, a quality of a workpiece surface can be improved, and a tool wear and the like can be suppressed.

The invention relates to a posture control method for an airship staying on the stratosphere. Aiming at the posture control problem of the airship staying on the stratosphere, a fuzzy variable structure decoupling control method is adopted and an input and an output of a nonlinear posture control system are decoupled into linear subsystems of three channels by feedback linearization; a sliding mode variable structure is utilized to control an invariance design posture control system which is uncertain for a model and has disturbance to the outside, so that the robustness of the system is ensured; and a control law parameter is regulated by a fuzzy rule on line, so that the buffeting caused by the control of the sliding mode variable structure is effectively inhibited and the dynamic performance of the system is improved.

In a steerage locking system for a vehicle, including a control knob mounted to a rotor capable of being turned from a LOCK position via an ACC position and an ON position to a START position, the control knob is detachably fastened to a front end of the rotor by a screw member from axially outside the rotor. Thus, the maintenance such as exchange of the control knob is facilitated.

An apparatus includes an external input device that allows setting of the amount of runout and the phase of each cutting edge, a computation device that acquires the rotational phase of a tool and that computes the angular velocity and the phase of vibration of two, X-axis and Y-axis, feed shafts on the basis of the input amount of runout and angular velocity of each cutting edge to generate a feed shaft control signal, and a numerical control device that controls feed in the X-axis and the Y-axis directions. The numerical control device relatively vibrates a workpiece in synchronization with the angular velocity of the tool on the basis of the results of computation performed by the computation device.

The invention discloses a robust fault tolerant control method for a multi-time-delay quadrotor helicopter flight control system. On the condition that a sensor breaks down, a quasi-integral type sliding mode prediction model with global robustness is constructed. On the basis of a particle swarm optimization algorithm, the rolling optimization process is improved, and the convergence rate is increased. Due to a reference trajectory containing compensation terms, and poor influences caused by system uncertainty, multiple time delays and sensor faults on the system performance are restrained. The method is used for robust fault tolerant control of a sensor fault uncertain discrete system with state time delay and input time delay.

A vibration damping tool having the following structure is provided. In the vibration damping tool, a hollow portion is formed in the interior of the distal end portion of a tool body and one end of a weight member is connected to the inner wall surface of the distal end side of this hollow portion. A gap created between the outer peripheral surface of the weight member and the inner wall surface of the hollow portion is filled with a visco-elastic body. The one end of the weight member is formed as a narrow diameter shaft portion. The tool body can be divided into two and freely removed from and reattached at a dividing surface located on the base end side of the hollow portion. A hole portion is formed inside the other end of the weight member by hollowing out the interior thereof. Chatter vibration is thus absorbed using a simple structure without there being any effects from heat generated during cutting processing.

The invention provides a flutter suppression device for an airplane model, which is used for suppressing the flutter of the airplane model in a wind tunnel test of an airplane flutter model. The flutter suppression device comprises a hollow shell, a sliding block, a driving component and a control component, wherein the sliding block is movably arranged in the shell; the driving component is arranged in the shell and drives the sliding block to move in the shell; and the control component controls the work of the driving component. The flutter suppression device for the airplane model suppresses the flutter of the model by changing the gravity center of a wing or a tail wing of the airplane flutter model; the device is directly arranged on the wing and the tail wing of the airplane flutter model, so a pulley and a protective rope are not required to be arranged in a wind tunnel any more, and the flow field quality of the wind tunnel cannot be influenced; in addition, the flutter suppression device is directly arranged in the airplane flutter model, so the device is not influenced by the sizes of the airplane flutter model and the wind tunnel.

The present invention discloses a flexible spacecraft sensor fault adjustment method, belonging to the field of aerospace flight control technology. A fault estimation module and a fault tolerance controller are mainly employed by the flexible spacecraft sensor fault adjustment method, and the method comprises the steps that: a filter and an adaptive observer are employed to form a fault estimation module; fault estimation information and sensor output signals are employed to establish the fault tolerance controller through combination of adaptive integral sliding mode control technology; through adoption of the Lyapunov stability theory, the asymptotic stability of a system is proved in a condition of generation of sensor faults; and finally, a simulation experiment result proves the validity of the method provided by the invention. The fault tolerance control problem when sensor measurement offset faults are generated in an operation process of a flexible spacecraft is solved so thataccurate control of an attitude angle in the sensor fault condition is achieved and the system has a high tolerance capability for the faults; and moreover, the method fully takes the consideration of disturbances generated by spacecraft parameter uncertainty and flexible accessories in the design process and is suitable for engineering application.

The invention discloses a robust fault-tolerant control method for small unmanned aerial vehicle flight control system. According to the discrete system with parametric uncertainties and time-varying delays in the case of actuator failure, a simulated-integral sliding mode prediction model is constructed. The model can ensure the global robustness of an entire dynamic process and deal with the influence of the fault incurred from the parametric uncertainties and time-varying delays on the progressive stability of the sliding mode. Through the use of the improved chaotic particle swarm optimization (PSO) algorithm to improve the rolling optimization process, the method can effectively avoid the problems that the traditional particle swarm algorithm is easy to fall into the local extreme point in the excellence seeking process and that the convergence rate is slow. In the invention, a new reference trajectory is proposed, which can reduce the influence of system uncertainty and time-varying delay to an acceptable range through compensation, and can also suppress the buffeting phenomenon of the sliding mode obviously. The invention is used for the robust fault-tolerant control for a discrete system with parametric uncertainties and time-varying delays in the case of actuator failure.

The damping property of a rear rolling bearing (133) is adjusted by controlling a damping force that is applied by damping application means (5, 134) based on, for example, the type of a tool (T). Thus, it is possible to provide the optimum damping properties for various tools that differ in natural vibration, and to suppress the generation of chattering of the various tools. As a result, it is possible to increase the cut amount per unit time to increase the productivity.

The indexable insert of the present invention has a cutting edge at the end of a stick-shaped portion projecting from a tool base. The base is shaped to ensure effective clamping, thereby avoiding chatter and backlash. A cutting edge and a rake face are provided at the end of the stick-shaped portion, which is also provided with a side relief face so that chips cut from the workpiece are smoothly carried away. The cutting edge extends sideways beyond the side relief face so that the insert can effectively cut the walls of small and deep holes.

A vehicular illumination device includes a light distribution control unit, a determination unit and a control unit. The light distribution control unit performs an alteration control of a vehicular illumination unit so as to alter a light distribution with respect to an illumination object detected by a detection unit. When the illumination object ceases to be detected, the determination unit determines whether or not there is a need to maintain the alteration control in a current state. When it is determined that there is a need to maintain the alteration control in the current state, the control unit controls the light distribution control unit so as to maintain the alteration control in the current state.

A method and apparatus for manufacturing a bolt capable of mass-producing a multiple screw bolt such as a so-called double screw bolt at a low unit price, and a thread rolling die for use therein. The apparatus for manufacturing a bolt comprises a pair of thread rolling dies (1) which are arranged opposite to each other at a predetermined interval, and a bolt supporting unit (2) which supports a cylindrical bolt material (3) in a predetermined position. The thread rolling dies (1) are provided with a transfer pattern (4) having a coarse thread portion (5) which is part of a coarse thread formed by developing a coarse screw, and projections (6) which are part of a fine thread (6a) formed by developing a fine screw as shown by an imaginary line (6a), the fine thread (6a) being formed cyclically on a root portion (5a) of the coarse thread according to a phase shift between the fine thread and the coarse thread.

The invention discloses a three-dimensional flight path tracking method for an unmanned airship. The three-dimensional flight path tracking method comprises the steps of firstly, calculating an error amount by use of a given instruction flight path and an actual flight path, secondly, designing a flight path control law by use of a sliding mode control method and then calculating a flight path control quantity; in order to effectively suppress buffeting caused by sliding mode control, designing a neural network sliding mode control law by taking a sliding mode surface and the change rate as the input variables of a neural network and taking a control gain as the output variable of the neural network; adjusting the control gain on line by virtue of the self-learning function of the neural network. According to the three-dimensional flight path tracking method for the unmanned airship, the mathematical model of the space motion of the unmanned airship is established aiming at the flight path tracking problem of the unmanned airship; with the model as a control object, the flight path control law is designed by use of the sliding mode control method; in order to suppress buffeting, the neural network sliding mode control law is designed by taking the sliding mode surface and the change rate as the input variables of the neural network and taking the control gain as the output variable of the neural network, and the control gain is adjusted on line by virtue of the self-learning function of the neural network so as to suppress buffeting, and therefore, the system performance is improved.

The invention provides an on-orbit refueling spacecraft attitude control method, and the method comprises the steps: firstly calculating an error amount through a given target attitude and actual attitude; secondly calculating an auxiliary variable and a selection reaching law, introducing an inertia self-adaption law and a control gain self-adaption law, and building a self-adaption sliding mode attitude control law; thirdly taking an absolute value of a sliding mode and a first-order differential thereof as the input of a fuzzy adjuster so as to effectively inhibit the vibration of sliding mode control, taking the thickness of a sliding mode boundary layer as the output of the fuzzy adjuster, building a self-adaption sliding mode attitude control law with a fuzzy boundary layer, and carrying out the online adjustment of the thickness of the sliding mode boundary layer through the fuzzy adjuster. A closed-loop system controlled through the method can enable the actual attitude to be stably adjusted to a target attitude, and achieves the good robustness and control precision for a rotational inertia time varying effect and external disturbance. The method provides an effective means for the engineering implementation of the on-orbit refueling spacecraft attitude control.

It relates to a dual acting hammer modified from ordinary hammers. It comprises the hammer head and hammer handle, with the head contained with sealed and movable blocks. It features in the once time for time hammering with improved hammering effect, being more accurate, reduced or illuminated vibration resulted from counteraction, simple structure, same shape with the ordinary hammer after quick resetting of blocks. It can be used for hammering tools like hack, handle axe, axe, tennis racket, and golf pole and so on.