scholarly journals Position-insensitive estimation of mass from limit cycle of velocity feedback relay system with Spring

2021 ◽  
pp. 002029402110218
Author(s):  
Takeshi Mizuno ◽  
Taku Egawa ◽  
Masaya Takasaki ◽  
Yuji Ishino
Keyword(s):  
Limit Cycle ◽  
Measurement System ◽  
Mass Measurement ◽  
Relay Feedback ◽  
Restoring Force ◽  
Estimation Formula ◽  
Positive Threshold ◽  
Modified Formula ◽  
New Formula ◽  
Force Compensation

Mass measurement using relay feedback of velocity and restoring force compensation is investigated for determining the mass of an object under weightless conditions. In the measurement system, the velocity of the object is fed back through a relay with hysteresis and the force acting on the object is switched from a positive value to a negative value when the velocity reaches a positive threshold and vice versa. As a result, a limit cycle is induced in the measurement system and the mass is estimated based on the period of the limit cycle. In addition, restoring force compensation with a spring is introduced to avoid the drift of the trajectory. This compensation makes the static equilibrium state unique. However, the trajectory still drifts slightly. It causes some error in measurement when a simple formula of estimating mass is applied. To eliminate such an error, a new formula is derived to estimate the mass independently of the position of the trajectory that is determined by the switching positions in the relay actions. When the switching positions deflect from the origin at which the spring is in the natural length, the trajectory is not at the center and becomes asymmetric. It is analytically shown that the period of the limit cycle is minimum when the switching positions are at the origin. It indicates that mass is overestimated with the simple estimation formula when the trajectory is not at the center. The validity of the modified formula and the analytical results are confirmed experimentally.

scholarly journals Realization of Stable Trajectory in Mass Measurement System Using Relay Feedback of Velocity and Restoring Force Compensation

2019 ◽  
Vol 12 (3) ◽  
pp. 68-75
Author(s):  
Takeshi MIZUNO ◽  
Keisuke NISHIZAWA ◽  
Masaya TAKASAKI ◽  
Yuji ISHINO ◽  
Masayuki HARA ◽  
...  
Keyword(s):  
Measurement System ◽  
Mass Measurement ◽  
Relay Feedback ◽  
Restoring Force ◽  
Stable Trajectory ◽  
Force Compensation

scholarly journals Mass Measurement System Using Relay Feedback with Hysteresis

2008 ◽  
Vol 2 (1) ◽  
pp. 188-196 ◽  
Author(s):  
Takeshi MIZUNO ◽  
Takahiro ADACHI ◽  
Masaya TAKASAKI ◽  
Yuji ISHINO
Keyword(s):  
Measurement System ◽  
Mass Measurement ◽  
Relay Feedback

scholarly journals AIR PRESSURE CONTROLLED MASS MEASUREMENT SYSTEM

2013 ◽  
Vol 24 ◽  
pp. 1360002
Author(s):  
RUILIN ZHONG ◽  
JIAN WANG ◽  
CHANGQING CAI ◽  
HONG YAO ◽  
JIN'AN DING ◽  
...  
Keyword(s):  
Measurement System ◽  
Pressure Range ◽  
Mass Measurement ◽  
Air Pressure ◽  
Air Density ◽  
Airtight Chamber ◽  
And Control ◽  
Automatic Mass ◽  
Pressure Controlled ◽  
Control Part

Mass measurement is influenced by air pressure, temperature, humidity and other facts. In order to reduce the influence, mass laboratory of National Institute of Metrology, China has developed an air pressure controlled mass measurement system. In this system, an automatic mass comparator is installed in an airtight chamber. The Chamber is equipped with a pressure controller and associate valves, thus the air pressure can be changed and stabilized to the pre-set value, the preferred pressure range is from 200 hPa to 1100 hPa. In order to keep the environment inside the chamber stable, the display and control part of the mass comparator are moved outside the chamber, and connected to the mass comparator by feed-throughs. Also a lifting device is designed for this system which can easily lift up the upper part of the chamber, thus weights can be easily put inside the mass comparator. The whole system is put on a marble platform, and the temperature and humidity of the laboratory is very stable. The temperature, humidity, and carbon dioxide content inside the chamber are measured in real time and can be used to get air density. Mass measurement cycle from 1100 hPa to 200 hPa and back to 1100 hPa shows the effective of the system.

The Finite Element Analysis in Measurement System of Airplane Fuel Mass

2011 ◽  
Vol 301-303 ◽  
pp. 147-152
Author(s):  
Xiu Wu Sui ◽  
Xiao Guang Qi ◽  
Da Peng Li ◽  
Guo Xiong Zhang ◽  
Yu Ming Fan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Measurement System ◽  
Mass Measurement ◽  
Element Analysis ◽  
Fuel Mass ◽  
The Finite Element Analysis ◽  
Level Sensor ◽  
Level Meter ◽  
Fuel Level

The paper presents the measurement system of the air plane fuel mass consisting of cylinder shell resonating density meter and double cylinders capacitance level meter. The finite element analysis method of ANSYS10.0 is used to analyze the performance of cylinder shell resonator density meter and double cylinders capacitance fuel level sensor. On the base of simulation, the cylinder shell is 45mm in length, 9mm in radius, and 0.08mm in thickness, the material is 3J53; the double cylinders capacitance is 8mm in inside diameter, 23.6mm in outside diameter, and 550 mm in length. The experiments show the uncertainty of cylinder shell resonating density meter is only 0.12%, the uncertainty of double cylinders capacitance level meter is only 0.2%, and the uncertainty of the fuel mass measurement system is 0.4%.

Application of Dynamic Vibration Absorbers to Mass Measurement

1997 ◽  
Author(s):  
Takeshi Mizuno
Keyword(s):  
Measurement System ◽  
Mass Measurement ◽  
Vibration Absorber ◽  
Rotational Axis ◽  
Automatic Frequency ◽  
Dynamic Vibration Absorber ◽  
Measuring Device ◽  
Supporting Structure ◽  
Dynamic Vibration ◽  
Auxiliary Mass

Abstract A mass measurement system which uses a dynamic vibration absorber as measuring device is developed. It can measure mass even under weightless conditions like in space stations. In this system, an object to be measured is fixed to a rotating table (rotor) at a distance from the rotational axis. Since it makes the rotor unbalanced, a centrifugal force causes the supporting structure to vibrate during rotation. A dynamic vibration absorber attached to the structure is tuned or controlled to cancel the excitation force. When the structure does not vibrate, the amplitude of motion of the auxiliary mass equals the ratio of the amount of unbalance to the auxiliary mass. Therefore, the mass of the object is determined from the motion of the auxiliary mass. According to the measurement principles, the vibration of the supporting structure must be eliminated. A servocompensator with the performance of automatic frequency tracking is applied to reduce the vibration. Experimental results demonstrate that mass can be measured accurately with the developed measurement system.

An Application of Relay Feedback to Mass Measurement Under Weightless Conditions

2007 ◽  
Author(s):  
Takeshi Mizuno ◽  
Minoru Takeuchi ◽  
Yuji Ishino ◽  
Masaya Takasaki
Keyword(s):  
Measurement Errors ◽  
Mass Measurement ◽  
Dead Zone ◽  
Voice Coil Motor ◽  
Feedback System ◽  
Time Interval ◽  
Force Output ◽  
Relay Feedback ◽  
Relay Element ◽  
Measurement Object

Relay feedback was applied to measuring mass even under weightless conditions. A measurement object is driven by a force-output actuator. The motion of the object is controlled by a relay feedback system. The used relay element has dead zone and switches force acting on the object in relation to the position of the measurement object. The mass of the object is determined from the time interval measurement of the on-state and off-state periods. An apparatus was developed for experimental study. It uses a voice coil motor as an actuator, and a pair of photo interrupters for detecting the switching positions. The effects of system parameters on measurement accuracy were studied experimentally. Under the tuned conditions, the measurement errors were within 0.2[%]. Measurement on a base moving freely was also carried out.

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