Piezoelectric-shunt-damping-technology-based active and passive integrated control method for hydraulic pipeline fluid pulsation

Abstract

The invention discloses a multi-sample parallel experiment clamp capable of providing continuous clamping force. The multi-sample parallel experiment clamp is used for clamping multiple parallel samples on a material testing machine. The clamp is provided with an upper adapting positioning flange (1) and a lower adapting positioning flange (9), and the upper adapting positioning flange (1) and the lower adapting positioning flange (9) are vertically symmetrical. Positioning channels shaped like a Chinese character 'mi' are formed in each flange and are formed by three sliding grooves which pass through the circle center of the flange; four positioning frames are arranged on every two positioning channels which are perpendicular to each other respectively, and a positioning frame is arranged on the remaining positioning channel in the corresponding flange and passes through the circle center of the flange. The positioning frames are connected with the positioning flanges through bolts. Each positioning frame is of a U-shaped structure, and a pair of clamping blocks which is controlled to open and close through a special screw rod is arranged in each positioning frame. Through the structure of the clamp, the multiple parallel samples can be arranged on the material testing machine when the clamp is used, and the clamp has the advantages of being high in efficiency, continuous in clamping force, capable of preventing the samples from sliding off, easy to operate, economical and practical.

Description

technical field [0001] The invention belongs to the field of hydraulic pipeline fluid pulsation control, in particular to a hydraulic pipeline fluid pulsation active and passive integrated control method based on piezoelectric shunt damping technology. Background technique [0002] Since the axial piston pump is a hydraulic pump that alternately pumps medium, the instantaneous flow rate of its output must be a periodic function. It can be considered that there is a high-frequency pulsating flow superimposed on the average flow of the pump, and part of the flow pulsation is due to the discontinuous pumping process of each plunger, which is caused by the inherent characteristics of the pump, which is called Inherent flow pulsation. In addition, most of the flow pulsation is due to the sudden increase of the oil cylinder pressure from the oil suction pressure to the oil supply pressure. This huge pressure difference causes the oil in the pressure supply pipe to recoil back to ...

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Problems solved by technology

[0016] (1) At present, active control technology has been widely used in flexible aerospace structures, giant civil structures, and vehicle suspension systems (see Ding Wenjing's publication in the journal "Mechanics Progress" Volume 24 Issue 2 in 1994 for details) "Current Main Research Topics of Vibration Active Control"), but there are few reports on its practical application in the field of hydraulic pulsation control, and most of the research is still in the laboratory stage.

[0017] (2) The fluid pulsation active control that uses the deformation of the pipe wall of the hydraulic system to generate pressure pulsation waves is mostly used in low-pressure hydraulic pipeline systems, and is not suitable for high-pressure hydraulic systems

[0018] (3) At present, most of the driving materials of fluid actuators are made of piezoelectric ceramics or magnetostrictive materials. Since the actuator needs to generate secondary pulsation waves with the same amplitude and phase difference as the output pulsation wave of the pump, This makes the actuator bulky; and because in the high-pressure hydraulic system, the actuator has to bear a large load, making its driving voltage or magnetic field strength very large, which will cause a series of problems such as overheating of the actuator.

[0019] (4) As the hydraulic system (take the aircraft hydraulic system as an example) the plunger pump speed is getting faster and faster, the frequency of fluid pulsation is also getting higher and higher (taking the 9-piston aircraft hydraulic pump as an example, the fundamental frequency of fluid pulsation is 600Hz As mentioned above, the performance of the servo valve driven by smart materials has reached its limit at 600-700 Hz due to problems such as friction and self-heating, and it is powerless for the second harmonic, third harmonic and higher harmonic of fluid pulsation), This has become a bottleneck restricting the development of fluid pulsation active control based on the principle of bypass overflow

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