Servo Control Unit Research Articles

Research on high efficiency and high dynamic optimal matching of the electro-hydraulic servo pump control system based on NSGA-II

An electro-hydraulic servo pump control system (hereinafter referred to as EHSPCS) is a volume servo control unit that is highly integrated with servo motors, fixed-displacement pumps, hydraulic cylinders and functional valve groups. Because of its unique volume direct-drive control mode, the dynamic performance of the system is limited, and the thermal power loss is large, which seriously restricts the improvement of the working quality of the system. To improve the dynamic performance of the system and reduce the thermal power loss to the maximum extent, a multi-objective optimization design method for the EHSPCS is proposed by comprehensively considering the dynamic and efficient energy-saving characteristics of the system. The evaluation model of the dynamic period of the hydraulic cylinder and the thermal power loss of the servo motor are given. Parameters such as the electromagnetic torque of the servo motor, displacement of the hydraulic pump, and working area of the hydraulic cylinder are intelligently optimized by a non-dominated sorting genetic algorithm with elite strategy (NSGA-II). The Pareto front of multi-objective optimization and the corresponding Pareto solution set are obtained; thus, the optimal matching of the system characteristics is realized. Finally, the relevant theory of the multi-objective optimization algorithm is applied to optimize the performance parameters of the hydraulic servo motor, and the prototype is tested in engineering. The experimental results show that the dynamic period of the hydraulic servo motor is accelerated after optimization, and the thermal power loss is significantly reduced. The dynamic and efficient energy-saving characteristics of the system are improved, which further verifies the feasibility of the proposed theory.

A new multi-function servo control dynamic shear apparatus for geomechanics

In this paper, we report a new multi-function servo control dynamic shear test apparatus, DJZ-500. This apparatus consists of five parts, including power system, loading frame, servo control unit, cooling system and PC console. The normal load and shear load are measured by load cells with an accuracy of 0.1 kN; normal and shear displacement are measured by LVDTs with an accuracy of 0.1 μm. DJZ-500 has the dynamic and static loading modules, which can perform the force and displacement servo control experiments in both vertical and horizontal directions. In addition, the dynamic loading modules can execute the custom waveforms, which can be utilized to investigate the seismic response of rock and soil masses. We presented six sets of representative tests on sands to demonstrate these functions. Moreover, DJZ-500 can also preform the coupled shear-flow test with the pumping system to investigate the flow behavior in sheared rock fractures. This device makes up for the deficiency of the existing equipment, and promotes the study of frictional properties of geomaterials.

The Study on Design of Circuit Card Assembly on Servo Control Unit for Automated Resupply Vehicle K56

The Study on Design of Circuit Card Assembly on Servo Control Unit for Automated Resupply Vehicle K56

207 The Vascular Effects of Resveratrol on Aged Mouse Femoral Arteries

<h3>Background</h3> In addition to its antioxidant properties, resveratrol (RV) is also known for its vasodilating effects. Although some of the vasodilating mechanisms of RV have been attributed to increases in NO, it has been previously demonstrated that in dietary-obese rats, in which endothelial function is impaired, RV is able to promote &gt;95% dilation. Given the above observations, we hypothesised that RV treatment restores endothelial function and flow mediated dilation of femoral arteries in old mice. <h3>Methods</h3> To establish vasodilator responses, C57BL/6 male mice (105 weeks of age) were humanely euthanised in accordance with the ‘Animals (Scientific Procedures) Act 1986’ and Institutional guidelines. Sections of the femoral artery were carefully dissected and mounted between two glass cannulae and fixed in place on a modified pressure myograph chamber. Arteries were initially pressurised to an intravascular (lumenal) pressure of 60 mmHg and maintained at that pressure using a pressure servo-control unit. Lumen and internal diameters of the vessel were constantly measured using a video dimension analyser. Constrictor responses (Phenylephrine (Phe) 10^–9–10^–3 M) and endothelial-dependent dilator responses to acetylcholine (Ach; 10^–9–10^–3 M) and flow (5–10 µL·min^–1) in pre-constricted vessels (Phe 10^–5 M) were assessed in femoral arteries incubated for 1 hr in either RV (30 µM) or physiological saline solution (PSS). The dilator responses were calculated as percentage of the pre-constrictor diameter, <h3>Results and conclusion</h3> RV treatment had no significant effect on Ach-dependent dilator responses. Whereas intraluminal flow of 8µL·min^–1 increased the diameter of the femoral arteries by up to 80% of the original diameter when arteries were pre-constricted and incubated in PSS, we observed no dilation after treatment with RV. Our data suggest that RV may have differential effects on Ach-dependent and flow mediated dilator responses in femoral arteries from aged mice.

Design and Implementation of Motion Control System with Precise Driving Mechanism

In this paper, a motion control system based on 2-axis gimbal system is designed and implemented to drive a high speed and precision. The proposed system consists of the RS-422 interface, 2-axis gimbal platform, SCU (servo control unit) integrated with a high speed DSP chipset, SAU (servo amplifier unit), potentiometer sensor unit, and resolver sensor unit. The SCU using the DSP firmware is designed to get a fast response without an overshoot with step input and a RMS error of low probability with ramp input. The SAU using a voltage control is designed to resolve the zero-crossing distortion for precise motion. To verify the performance and stability of the implemented system, experiments are performed through a measurement of the time and frequency domain response in a laboratory environment by using a PXI (PCI extentions for instrumentation).

정밀구동메커니즘 적용 모션제어시스템 설계 및 구현

In this paper, a motion control system based on 2-axis gimbal system is designed and implemented to drive a high speed and precision. The proposed system consists of the RS-422 interface, 2-axis gimbal platform, servo control unit integrated with a high speed DSP chip-set, servo amplifier unit, potentiometer sensor unit, and resolver sensor unit. The servo control unit using the high speed DSP firmware is designed to get a fast response without an overshoot with step input and a RMS error of low probability with ramp input. The servo amplifier unit using a voltage control is designed to resolve the zero-crossing distortion for precise motion. To verify the performance and stability of the implemented system, experiments are performed through a measurement of the time and frequency domain response in a laboratory environment by using a PXI(PCI eXtentions for Instrumentation).

이중 곡률을 가지는 선박용 외판 성형을 위한 점진적 롤 성형 공정의 적용에 관한 실험적 연구

In order to manufacture a doubly curved sheet metal, the incremental roll forming process which adopts advantages such as the flexibility of the incremental forming process and continuous bending deformation of the roll forming process has been experimentally investigated. An experimental equipment was developed which was named as unit roll set (URS) consisting of two pairs of support rolls and an upper center roll. The upper roll equipped with the servo control unit is motor-driven and can be positioned in the vertical direction according to the user's commands. Four support rolls are idle, and they freely rotate only along the axis so as to transfer the plate more stably in the tangential direction of the rotation of the driving roll. In the process, the plate is deformed incrementally as deformation proceeds simultaneously in longitudinal and transverse directions. Through the experiments using URS, information regarding to forming schedules is found out to fabricate curved hull plates. This study demonstrates the further application of the incremental roll forming process in shipbuilding industries.

Investigation on full distribution CNC system based on SERCOS bus

A full distribution CNC system based on SERCOS bus is studied in accordance with the limitations of traditional PC-based motion card. The conventional PC-based motion control card is dispersed into several autonomous intelligent servo-control units with the function of servo driver. The autonomous intelligent servo-control units realize the loop control of position, velocity and current. Interpolation computation is completed in PC and the computational results are transferred to every autonomous intelligent servo-control unit by high speed SERCOS bus. Software or hardware synchronization technology is used to ensure all servomotors are successive and synchronously running. The communication and synchronization technology of SERCOS are also researched and the autonomous intelligent servo-control card is developed byself. Finally, the experiment of circle contour process on a prototype system proves the feasibility.

Iodine‐stabilized He‐Ne laser at λ=633 nm: design and international comparison

A portable He-Ne laser at 633 nm, frequency stabilized by saturated absorption in 127/ 2 and built at the Institute for Atomic Physics, Institute for Physics and Technology of Radiation Devices is discussed. The construction of laser head and electronic servo control unit is described. The principle of the arrangement of the electronic circuits in the electronic unit and the tuning procedure of the chosen components are presented. Recent results of an international comparison held at Bureau International des Poids et Mesures (BIPM) was used to characterize the performance of the RO.2 laser against the BIPM4 laser. The mean laser frequency difference calculated on a set of 13 matrix determinations was: ?v=vRO.2-vBIPM4=-1.23 kHz with a repeatability of R(vRO.2)= ±6.8 kHz. The frequency stability expressed as relative Allan variance for sampling time, ?=102 s, was calculated from a 40,000-s time interval as ?(v)/v=1.78×10-12. All measurements were made under the restrictions of the Recommendation 3 (CI-1992) for the lasers suitable for the practical realization of the meter.

Design and performance of compact iodine stabilized He-Ne lasers at lambda =633 nm with a short optical resonator

The authors deal with portable He-Ne lasers at 633 nm, frequency stabilized by saturated absorption in 127I2. The construction of two different types of laser heads and electronic servo control units is described. The Invar head with Invar resonator and interchangeable elements (mirrors, discharge tube and iodine cell) yields 14 hyperfine structure (HFS) components (a-n) of the R(127)11-5 absorption line of the molecular iodine at 633 nm. The fused silica head, an integral structure laser containing a discharge tube and an iodine cell in a fused silica resonator, offers 18 HFS components (a-r). The principle of the arrangement of the electronic circuits in the electronic unit is presented and the manual or automatic tuning procedure of the chosen components is described. Some results and applications of these lasers are presented in brief.

An experimental remote handling system

An experimental robotic remote handling system is described which has been constructed in order to investigate various engineering problems in advanced remote handling such as the man-machine interface, system control and communication. The device consists of a mobile and a control station. The mobile station comprises an electrical manipulator having seven degrees of freedom, a TV camera, a control sub-computer, a servo-control unit, radio transmitters and receivers, batteries, etc., which are mounted on a crawler-type vehicle. The control station is equipped with the master arm of the manipulator, radio transmitters and receivers, a TV monitor, a main control computer and its peripheral devices, etc. The manipulator can be operated in either a master-slave, a playback or a programmed control mode with the assistance of control computers. Communication between the mobile and the control stations is made using optical fibres or a radio link.

An Experimental Remote Handling Device

An experimental robotic remote handling device is described which has been constructed in order to investigate various engineering problems in advanced remote handling such as man-machine interface, system control, and communication. The device consists of a mobile station and a control station. The mobile station comprises an electrical manipulator having seven degrees of freedom, a TV camera, a control sub-computer, a servo-control unit, radio transmitters and receivers, batteries, etc. which are mounted on a crawler-type vehicle. The control station is equipped with a master-arm of the manipulator, radio transmitters, receivers, a TV monitor, a main control computer and its peripheral devices, etc. The manipulator can be operated in either master-slave, playback or programmed control mode with the assistance of the control computer. The communication between the mobile and the control stations is made using optical fibers or radio link.

Effects of a low protein diet during pregnancy of the rhesus monkey. II. Physiological adaptation of the infant1–3

Heart rate, respiratory rate, and ability to maintain body temperature were evaluated in six infants born to rhesus monkeys that had been fed a low protein diet throughout pregnancy. All infants were kept in incubators equipped with a “servo” control thermal unit that maintained the infants' skin temperature at 37.0 C (98.6 F). The thermal units were disconnected and the infants were exposed to room temperature (approximately 27 C) for 6-hr periods each day after 24 hr of age in order to determine the efficiency of thermal control mechanism. The thermal servo control units were “on” for a longer period of time in experimental animals than in control animals during the first 24 hr of life. Infants from mothers fed the low protein diets were also less able to maintain their own body temperatures after exposure to room temperature. This function was seriously compromised in two of the six experimental infants. The compromised temperature control mechanism seen in these infant monkeys is a serious and potentially lethal side-effect of protein-calorie malnutrition during pregnancy. The possible relationship of inadequate maternal nutrition to the inefficient thermal mechanism of certain “high risk” human newborns should be reevaluated.

Peripheral circulatory response to phototherapy in newborn infants.

SummaryCalf blood flow (CBF), calf skin temperature, incubator wall and ambient temperature, and respiratory rate, were measured in 8 newborn infants 10 to 127 hours of age, who were treated by phototherapy because of jaundice. During phototherapy (within 30 min) the CBF increased to a range of 30 to 80% above the control values of 8.8 ± 0.9 ml/min/100 g. The CBF is correlated directly with the leg skin temperature (γ= 0.724 and 0.588 at 15 and 30 min after phototherapy respectively). The increase in CBF was associated with a fall in incubator ambient temperature, the latter is a result of the use of servo control unit in monitoring incubator temperature by epigastric skin temperature. The increase in CBF is probably evidence of peripheral vasodilatation to facilitate evaporative heat loss. An increase in respiratory rate was also observed during phototherapy. The observed increase in heat loss (and water loss) from vasodilatation and increased respiratory rate serve as a basis for the increase in insensible water loss as previously reported.