276 results about "Residual vibration" patented technology

The invention provides a vibration active control method based on a secondary channel online identification FxLMS algorithm, a vibration active control system comprises a sensor, a vibration signal conditioner, an actuator, a piezoelectric power amplifier, a real-time control simulation system and a computer, and a built SPMFxLMS algorithm physical model is embedded in a computer controller. The SPMFxLMS algorithm physical model comprises a vibration response error signal calculation module, a control channel adaptive filter, an identification channel adaptive filter and an unknown secondary channel model, and the unknown secondary channel model is constructed according to the identification channel adaptive filter and updated in real time. The algorithm physical model constructed by the invention adopts an improved power scheduling strategy and an identification adaptive filter to update and calculate the vibration response time domain data of the controlled object, so that the obtained control voltage signal is reliable, the residual vibration quantity caused by identification noise is avoided, the vibration suppression effect is excellent, and the method has excellent noise immunity and applicability.

The invention relates to the technical field of industrial control, in particular to an industrial stacker intelligent control system based on machine vision, and the system comprises a state resolving module which is used for carrying out the feature region decoupling of original observation data, and resolving a position deviation matrix and a deformation state variable for a rigid subspace and a flexible subspace respectively; the dynamic modeling module is used for identifying the first-order inherent frequency and the damping ratio of the mechanical structure on line and establishing a second-order impedance contact model; the impedance control module is used for generating an expected speed based on the position deviation and adaptively adjusting an impedance parameter according to a deformation state so as to carry out compliant modulation on a speed vector; and the estimation shaping module is used for correcting system time lag by using a Kalman observer and inhibiting residual vibration in combination with a zero-vibration input shaper. Through multi-dimensional physical field fusion and dynamic modeling, the problem that a rigid control model is mismatched with a flexible operation object is solved, and self-adaptive compliant control and vibration-free accurate operation of the stacking machine in the unstructured environment are achieved.

The invention relates to the technical field of vibrator control, in particular to a driving voltage calibration method and device, electronic equipment, a medium and a program product, and is characterized in that residual vibration parameters and driving frequency of a vibrator are acquired, and the residual vibration parameters comprise a quality factor, an electromechanical coupling coefficient and resonance frequency; based on the residual vibration parameter and the driving frequency, the vibration parameter of the vibrator under the corresponding driving frequency can be calculated, and the vibration parameter can comprise one or more of acceleration, speed and displacement of vibration of the vibrator. The comparison result between the determined vibration parameters of the vibrator under different driving frequencies and the preset vibration parameters serving as the reference can be used for calibrating the driving voltage under the corresponding driving frequency, so that the vibrator is driven by the calibrated driving voltage, and the vibration consistency of the vibrator and the reference vibrator can be ensured.

The invention relates to the technical field of underwater acoustic engineering and ocean exploration, in particular to a multi-channel underwater acoustic signal transmitting and measuring system and a signal processing method, which are used for solving the problems that the existing multi-channel underwater acoustic signal processing generally depends on fixed threshold detection or simple time sequence alignment, and the signal processing efficiency is low. The problem that residual vibration, local noise abrupt change or multipath reverberation is easily misjudged as an effective first arrival signal in a complex underwater environment due to the fact that the influence of the physical response characteristic of a transducer on emission time calibration is not considered and effective verification on whether a candidate arrival structure accords with a sound wave propagation physical rule is lacked is solved. According to the invention, a multi-channel energy time sequence and hydrophone space geometrical relationship is fused through an underwater sound propagation initial physical judgment module, a judgment mechanism is constructed based on distance-time consistency of sound propagation, and self-consistent verification is realized by combining a cross-channel arrival sequence and sound velocity constraint. And the accuracy, the robustness and the physical interpretability of the judgment of the effective launching time of the underwater sound are obviously improved.

The invention relates to the field of electro connecting pressure gauges, in particular to an electro connecting pressure gauge with an alarm function, which comprises an external pipeline connected with an external pressure pipeline, the outer end face of the external pipeline is fixedly connected with a dial plate, and a transparent shield is embedded and matched on the dial plate; the pointer adjusting mechanism is used for adjusting the position of the pointer, and the pointer adjusting mechanism is arranged in the center of the transparent shield; the pointer mechanism is used for carrying out alarm processing when an upper limit is exceeded or a lower limit is lower, and the pointer mechanism is arranged on the dial plate and is protected by the transparent protective cover; wherein the pointer adjusting mechanism comprises a circular groove, the circular groove is formed in the top of the transparent protective cover, and according to the electric contact pressure gauge with the alarm function, a friction damper (such as metal sheet contact friction) is arranged on a reset path, vibration energy is consumed through friction, and impact and residual vibration of the second bourdon tube in the reset process are reduced.

The invention provides a tendon-driven mechanical arm flexible vibration control method based on a hybrid optimization strategy. The tendon-driven mechanical arm flexible vibration control method comprises the steps that a dynamic model of a tendon-driven mechanical arm is established; constructing a trajectory optimization model for suppressing residual vibration; solving the trajectory optimization model for suppressing residual vibration by using a hybrid particle swarm optimization strategy, and obtaining an expected trajectory; and designing a sliding mode controller based on an RBF neural network to actively track the trajectory so as to suppress residual vibration. According to the invention, a hybrid particle swarm optimization algorithm is adopted to optimize a motion trajectory, so that residual vibration is reduced, an expected trajectory for trajectory tracking is obtained, active control is combined to further suppress the residual vibration, and the tail end vibration amplitude is reduced by more than 50%; the self-adaptive neural network all-drive system control method is designed by combining the RBF neural network, so that the tail end vibration is further inhibited while the mechanical arm completes trajectory tracking, and the tracking error is smaller than 0.5 degree.

The invention provides a liquid discharge system which appropriately and easily determines the waveform of a drive signal for driving a piezoelectric element. The liquid ejection system includes a liquid ejection head, a transmission control unit, and a reception control unit. The liquid ejection head has a nozzle. A piezoelectric element driven by being supplied with a drive signal; a vibration plate that vibrates by being driven by the piezoelectric element; a pressure chamber which is filled with ink and to which pressure for ejecting the ink from the nozzle is applied by vibration of the vibration plate; and a detection circuit that detects residual vibration of the vibration plate after the piezoelectric element is driven. The transmission control unit transmits, to the server, residual vibration information indicating the residual vibration detected by the detection circuit. The reception control unit receives, from the server, adjustment information that is generated on the basis of the residual vibration indicated by the residual vibration information and that is used to adjust the waveform of the drive signal.

The utility model relates to the technical field of loaders, and discloses a loader cab damping device which comprises a loader cab, and a damping mechanism is arranged at the bottom of the loader cab. The damping mechanism comprises a bottom plate, damping blocks are fixedly connected to the four corners of the bottom of the bottom plate, a connecting plate is fixedly connected to the bottoms of the damping blocks through first bolts, a damper is fixedly connected to the bottom of the connecting plate, a spring is arranged on the outer side of the damper in a sleeving mode, and a supporting plate is fixedly connected to the bottom of the damper. According to the loading machine cab damping device, when the loading machine cab is impacted, the spring elastically deforms firstly to absorb part of impact energy, then the damping block and the damper play a role, and residual vibration energy is absorbed and dissipated; the damping block is matched with the damper and the spring, so that unnecessary deformation of the damping mechanism is effectively avoided, and the stability and comfort of the cab of the loading machine are ensured.

The invention relates to a radar probe aftershock suppression method, device and system and computer equipment. The method comprises the following steps: acquiring a vibration signal of a radar probe; determining a residual vibration signal based on the vibration signal, decomposing the residual vibration signal into a plurality of residual vibrator signals, and determining waveform parameters of the plurality of residual vibrator signals; correspondingly determining a plurality of suppressor sub-signals based on the waveform parameters of the plurality of residual oscillator sub-signals, and superposing the plurality of suppressor sub-signals to obtain a suppression signal; and sending the suppression signal to the radar probe, so that the radar probe suppresses residual vibration based on the suppression signal. On one hand, the residual vibration of the probe can be attenuated to zero in a shorter time, so that the measurement precision and reliability of the radar are effectively improved; and on the other hand, real-time optimization can be carried out for different detection distances and object conditions, the real-time performance, effectiveness and flexibility of the residual vibration suppression effect are kept, and radar detection can be suitable for more application scenes.

The invention relates to the technical field of mechanical arm vibration suppression, in particular to a mechanical arm tail end active vibration suppression method and system based on predictive compensation, and the method comprises the following steps: S1, collecting the three-axis acceleration, angular velocity and vibration spectrum data of a mechanical arm in real time through a high-frequency IMU sensor; monitoring a rolling angle, a pitch angle and a yaw angle of a base attitude through an auxiliary IMU sensor, and fusing double IMU data through a Kalman filtering algorithm; s2, generating a pre-compensation torque based on the fused data, optimizing a model gain coefficient in combination with a real-time deviation between a frequency spectrum actually measured by a high-frequency IMU sensor and a model prediction frequency spectrum, and correcting and outputting the pre-compensation torque in real time; and S3, the corrected compensation torque is injected into a feed-forward channel of a joint motor control loop, vibration suppression torque is output to a joint execution mechanism through a high-gain controller, and residual vibration at the tail end of the mechanical arm is counteracted in real time. According to the invention, an active vibration suppression system can be constructed to solve the problem of real-time vibration suppression under multi-source disturbance coupling.

The invention discloses a system for suppressing vibration in the machining process of a numerical control machine tool and a vibration suppression method. The system comprises a vibration sensing module, a signal processing and decision module, a vibration suppression execution module and a feedback and optimization module. The vibration sensing module monitors vibration information including vibration frequency, vibration amplitude and vibration sources in the machining process of the machine tool in real time and sends the vibration information to the signal processing and decision module; the signal processing and decision-making module performs vibration feature extraction according to the received vibration signal, and generates a reverse suppression signal based on a vibration feature adaptive filtering algorithm or model prediction control; the vibration suppression execution module performs vibration suppression according to the received reverse suppression signal; and the feedback and optimization module detects the residual vibration quantity and the state of the vibration suppression execution module, adjusts the control parameters of the vibration suppression execution module in real time, and forms a self-adaptive vibration suppression closed loop.

The invention relates to the technical field of composite material testing, in particular to a vertical impact testing method and device for an airplane all-carbon seat, and the method comprises the steps: carrying out a vertical impact test on an all-carbon fiber sample; determining whether the impact load can be used for the vertical impact test of the full-carbon seat of the target aircraft according to the failure evaluation value; performing a multi-stage vertical impact test on the target aircraft all-carbon seat sample, obtaining strain rates of a plurality of test points of a backrest of the target aircraft all-carbon seat, and obtaining a strain characterization value; when it is judged that the impact of the target aircraft all-carbon seat sample does not meet the preset standard according to the strain characterization value, whether the impact of the target aircraft all-carbon seat sample meets the preset standard or not is judged secondarily according to the strain offset characteristic value; and according to the residual vibration evaluation value of the target aircraft all-carbon seat sample, determining the reason that the impact of the target aircraft all-carbon seat sample does not meet the preset standard, thereby improving the impact test precision.

A dynamic-balance test method for a rigid rotor includes: acquiring a counterweight influence coefficient library, initial vibration swing data and an initial vibration vector; determining an initial test weight mass and an initial test weight phase according to the initial vibration swing data and the counterweight influence coefficient library, and triggering a speed increase test according to the initial test weight mass and the initial test weight phase to obtain a target vibration vector; determining a target configuration influence coefficient according to the initial vibration vector, the target vibration vector and the initial test weight mass; calculating a residual vibration swing value; and determining a target test weight adjustment scheme according to the residual vibration swing value, a rotor operation vibration standard, a target test weight mass and a target test weight phase.

In order to solve the problems that in an existing hemispherical harmonic oscillator quality leveling technology, the inherent rigid axis positioning efficiency is low, and manual intervention is relied on, the invention provides a method for rapidly positioning the azimuth of an inherent rigid axis of a hemispherical harmonic oscillator based on pulse broadband excitation and quasi standing wave response and a corresponding leveling device. Through an analytical expression of a main standing wave and an auxiliary wave in a second-order four-amplitude resonance working mode, a double-excitation vibration stopping system (comprising two knocking hammers and a vibration stopping hammer with the azimuth difference of 22.5 degrees odd times) is ingeniously designed, and the azimuth of an inherent rigid shaft is quickly positioned by combining orthogonal detection signals. According to the method, the limitation on the excitation direction and the detection direction is relaxed, and through the design of the vibration stopping hammer, the positioning efficiency of the inherent rigid shaft is improved, and the extraction precision of residual vibration on the characteristic parameters can be avoided. The formed hemispherical resonator leveling device provides reliable technical support for batch production of high-precision hemispherical resonator gyroscopes.

A liquid ejecting system includes a liquid ejecting head, a transmission control portion, and a reception control portion. The liquid ejecting head includes a nozzle, a piezoelectric element that is driven by a drive signal being supplied, a diaphragm that vibrates by driving the piezoelectric element, a pressure chamber which is filled with an ink and to which a pressure for ejecting the ink from the nozzle is applied by the vibration of the diaphragm, and a detection circuit that detects residual vibration of the diaphragm after the piezoelectric element is driven.The transmission control portion transmits residual vibration information indicating the residual vibration detected by the detection circuit to a server. The reception control portion receives adjustment information for adjusting a waveform of the drive signal, which is generated based on the residual vibration indicated by the residual vibration information, from the server.

The invention provides an anti-saturation fault-tolerant control method and device for a double-flexible-arm space robot, relates to the field of robot control, and solves the multiple challenges that in the prior art, a flexible mechanical arm faces continuous and difficult vibration suppression, an actuator is prone to failure, torque is limited, task time is constrained and the like. The dynamic state of the system is unstable; and the control capability is limited. The method comprises the steps that a hypothesis modal method and a momentum conservation theorem are combined to derive a double-flexible-arm space robot kinetic equation in a Lagrange form; a flexible system singular perturbation technology is utilized to obtain a slow-varying subsystem for representing rigid motion characteristics of a mechanical body and a quick-varying subsystem for representing residual vibration characteristics of a rod piece; for the slow-varying subsystem, designing a fixed-time anti-saturation fault-tolerant controller based on an extreme learning machine and a torque output function; and designing an anti-saturation controller based on state variable negative feedback for the quick change subsystem. The method is used in the robot control process.

The invention provides an anti-impact six-degree-of-freedom quasi-zero stiffness vibration isolation platform which comprises a first-stage vibration isolation layer and a second-stage vibration isolation layer and is characterized in that the first-stage vibration isolation layer is composed of four self-adaptive quasi-zero stiffness vibration isolation systems and used for supporting a panel and isolating vibration from equipment or the ground; the second-stage vibration isolation layer is composed of four active vibration isolation systems and used for further attenuating residual vibration and restraining internal motion disturbance of equipment. According to the quasi-zero-stiffness vibration isolator, the core problem that a traditional quasi-zero-stiffness vibration isolator cannot adapt to dynamic load changes and the anti-impact requirement is solved, a high-reliability and ultra-quiet environment is provided for high-end precision manufacturing, six-degree-of-freedom vibration control can be achieved, a vibration isolation belt is wider, vibration isolation of a 0.1-500 Hz vibration source can be achieved, the bearing capacity is large, the 20000 kg bearing requirement can be met, and the quasi-zero-stiffness vibration isolator is suitable for large-scale popularization and application. The device can adapt to precise instruments of different models, and is wide in application range and high in universality.

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.

The invention discloses an ammunition automatic filling robust control method based on singular system IL disturbance estimation, and aims to solve the problems of flexible transmission, parameter uncertainty, periodic external disturbance, residual vibration and the like in an automatic filling system. According to the method, a fast-slow dual-time-scale cooperative control architecture is constructed, a slow subsystem adopts a disturbance self-adaptive PD controller, low-frequency periodic disturbance is estimated and compensated online in combination with an iterative learning mechanism, and the trajectory tracking precision is improved; the fast subsystem carries out real-time estimation and feedforward suppression on high-frequency elastic vibration based on an extended state observer (ESO); and filtering and amplitude limiting are further carried out on slow and fast control inputs, a self-adaptive scheduling strategy based on tracking errors is designed, and the slow and fast control inputs are dynamically fused to generate a final control instruction. According to the method, only motor end position / speed measurement is needed, a load end sensor is not needed, high precision, high robustness and excellent vibration suppression capability are achieved, and the dynamic performance and complex condition adaptability of automatic ammunition filling are remarkably improved.

The invention relates to a head unit and a liquid ejecting apparatus. The head unit includes: an ejection unit that includes a piezoelectric element driven according to a drive signal and ejects a liquid according to the driving of the piezoelectric element; a waveform shaping circuit to which a first residual vibration signal corresponding to residual vibration generated by the drive signal is input and which outputs a second residual vibration signal obtained by shaping the waveform of the first residual vibration signal; a temperature detection circuit that outputs a temperature information signal corresponding to the temperature of the waveform shaping circuit; and a determination circuit configured to determine a state of the ejection unit, the waveform shaping circuit including: an amplification circuit configured to amplify the first residual vibration signal; and an amplification factor setting circuit that sets the amplification factor of the amplification circuit, the waveform shaping circuit outputs a second residual vibration signal based on the signal amplified by the amplification circuit, the amplification circuit and the amplification factor setting circuit constitute a single semiconductor device, and the determination circuit determines the state of the ejection unit based on the second residual vibration signal and the temperature information signal.

An ink jet device according to the present disclosure is provided with: a partition wall that partitions a pressure chamber that stores ink ejected from a nozzle; a diaphragm that presses the pressure chamber; a first piezoelectric element disposed in a portion of the diaphragm corresponding to the pressure chamber; a second piezoelectric element disposed in a portion of the diaphragm corresponding to the partition wall; and a first vibration damping part which is provided between the first piezoelectric element and the second piezoelectric element, and which is in contact with the diaphragm to reduce residual vibration of the diaphragm.

The utility model relates to the technical field of washing machines, in particular to a hydraulic mechanism for an industrial washing machine, which is characterized in that vibration and noise generated during working of a hydraulic pump are preliminarily reduced by arranging a sound insulation shock pad and under the action of a shock pad made of butadiene rubber, so that the working efficiency of the hydraulic pump is improved, and the service life of the hydraulic pump is prolonged. Residual vibration is further conducted downwards through the washing machine body, secondary damping is conducted through damping springs and damping pads under the action of the damping pads made of butadiene rubber, and the vibration generated in the working process of the washing machine is further reduced; therefore, the problems that in the working process of an existing industrial washing machine, large vibration is likely to be generated, the influence on the surrounding environment of the washing machine is large along with strong noise, and the service life of the industrial washing machine is likely to be shortened due to vibration are solved, the service life of the industrial washing machine is prolonged accordingly, and the service life of the industrial washing machine is prolonged. And the practicability of the device is enhanced.

The invention discloses a rotor dynamic balance method giving consideration to vibration threshold control and counterweight vibration elimination efficiency, and the method comprises the steps: obtaining an original vibration signal and a key phase signal of a rotor through data collection equipment, and obtaining a vibration signal and a key phase signal after a trial weight is added; the amplitude and phase of an original unbalance signal of the rotor and the amplitude and phase of an unbalance signal after the trial weight is added are obtained after analysis and calculation, an optimization function with the maximum comprehensive vibration of balance weight reduction under the balance rotating speed as the target is constructed, and rotor dynamic balance optimization calculation is carried out based on a raccoon optimization algorithm. The balance weight giving consideration to the rotor vibration threshold constraint and the balance weight efficiency is obtained, and the maximum vibration is reduced through the minimum balance weight under the condition that the vibration control target is met; according to the method, the problem that in the traditional dynamic balance mass calculation process, a single-target optimization algorithm represented by minimum residual vibration, maximum vibration minimization and the like is difficult to consider the residual vibration amplitude and the counterweight balance efficiency at the same time is solved.

The invention discloses a packaging method for suppressing residual vibration of a vibrating diaphragm, which relates to the technical field of chip packaging and comprises the following steps of: painting glue: painting patch glue on a carrier according to a preset thickness; and embedding the chip: inversely buckling the chip to enable the lining body of the chip to be embedded into the patch, enabling the vibrating diaphragm of the chip to be parallel to the carrier, and ensuring that the sound hole in the carrier is located in the projection range of the vibrating diaphragm. The chip is embedded in the patch adhesive instead of being suspended on the patch adhesive, and the packaging process of the carrier is improved, so that residual vibration is effectively reduced; when the thickness of the patch glue and the glue climbing height range are determined, sound holes with different sizes can be selected according to chips with different frequencies; when the size of the sound hole is fixed, different patch adhesive thicknesses and adhesive climbing height ranges can be selected according to chips with different frequencies, and the practicability is high.

The invention discloses a satellite vibration suppression system and method, a storage medium and a computer program product. The system comprises a passive vibration isolation module used for isolating first vibration generated by satellite vibration source equipment; the active suppression module is used for counteracting second vibration generated by the satellite vibration source equipment; wherein the second vibration is residual vibration except the first vibration isolated by the passive vibration isolation module, and the vibration frequency of the first vibration is higher than that of the second vibration. The technical problem that the effective load performance of a satellite is limited due to the fact that a traditional single passive or active vibration suppression method cannot effectively cover broadband vibration from high frequency to low frequency is solved.

To provide a head unit of which discharge part state determination accuracy is improved.SOLUTION: A head unit comprises: a discharge part which includes a piezoelectric element driven by a driving signal, and discharges liquid in response to drive of the piezoelectric element; a waveform shaping circuit to which a first residual vibration signal in response to residual vibration generated by the driving signal is inputted and which outputs a second residual vibration signal in which the waveform of the first residual vibration signal is shaped; a temperature detection circuit which outputs a temperature information signal in response to the temperature of the waveform shaping circuit; and a determination circuit which determines the state of the discharge part. The waveform shaping circuit has an amplifier circuit for amplifying the first residual vibration signal and an amplification factor setting circuit which sets an amplification factor of the amplifier circuit, and outputs the second residual vibration signal based on a signal amplified by the amplifier circuit. The amplifier circuit and the amplification factor setting circuit are configured as one semiconductor device, and the determination circuit determines the state of the discharge part on the basis of the second residual vibration signal and the temperature information signal.SELECTED DRAWING: Figure 19

To suppress an increase in the length of a unit period TU, which is a cycle for driving a discharge part D, when determining the state of the discharge part D.SOLUTION: An ink-jet printer 1 comprises: a drive signal generation unit 4 that generates a drive signal COM; a discharge part D that includes a nozzle N, a piezoelectric element PZ driven by the drive signal COM, and a cavity CV that discharges ink from the nozzle N in response to drive of the piezoelectric element PZ; a first inspection signal generation circuit 340 to which a residual vibration signal generated according to vibrations remaining in the discharge part D after the piezoelectric element PZ has been inputted, and which generates a pseudo residual vibration signal corresponding to the residual vibration signal; a second inspection signal generation circuit 350 to which the residual vibration signal is inputted, and which generates a detected residual vibration signal obtained by removing frequency components other than predetermined frequency components from the residual vibration signal; and an inspection unit 6 to which either of the pseudo residual vibration signal and the detected residual vibration signal is selectively inputted, and which determines the state of the discharge part D on the basis of the inputted signal.SELECTED DRAWING: Figure 9

A liquid ejection apparatus includes an ejection unit including a nozzle, a pressure chamber, and a piezoelectric element that applies pressure fluctuations to a liquid in the pressure chamber according to a supplied drive signal, a drive signal generation unit that generates the drive signal, and a detection unit that detects a residual vibration generated in the pressure chamber. The drive signal generation unit generates the drive signal having a detection waveform including an expansion element that changes in potential from a first potential to a second potential to expand the pressure chamber, and an expansion potential maintaining element that maintains the second potential following the expansion element. A length of a period from a start to an end of a change in potential from the first potential to the second potential is equal to or greater than a length of a natural vibration cycle of the ejection unit.

To solve the problem that maintenance of a recording part may be completed in a state where it is not confirmed whether the executed maintenance of the recording part is acceptable or not.SOLUTION: A recording device 1 comprises: a recording part 10 that discharges ink Li from a nozzle N communicated with a liquid chamber 17, by changing pressure in the liquid chamber 17 storing the ink Li by driving a discharging element 15; a jetting body 71 that performs maintenance of the recording part 10 by making a droplet of maintenance liquid Lc impact on the nozzle N; a detecting part 95 that detects residual vibration occurred in the liquid chamber 17 by driving the discharging element 15, after the jetting body 71 executes maintenance of the recording part 10; and a control part 90. The control part 90 determines whether the maintenance of the recording part 10 is acceptable or not, on the basis of a detected result by the detecting part 95.SELECTED DRAWING: Figure 1

The invention provides a control method and system of a directional injection device, the directional injection device and a fire fighting truck, and the method comprises the steps: firstly obtaining a first-order modal frequency of a boom structure, and calculating a natural period according to the first-order modal frequency; adjusting injection parameters of the directional injection device to control injection recoil force; monitoring the change of the jet recoil force; under the condition that the change of the jet recoil force does not meet the preset change requirement, the adjusting step and the monitoring step are executed repeatedly till the change of the jet recoil force meets the preset change requirement; the preset change requirement is represented as a proportional relation between the change of the jet recoil force and the inherent period. By controlling the change of the jet recoil force, the impact response of the boom structure under the excitation of the jet recoil force is greatly reduced, the dynamic load coefficient and the residual vibration are reduced, the weight and the cost of the boom structure do not need to be increased, and the jet timeliness is high.