Mass measurement using a relay feedback system was studied experimentally. The measurement system has an on-off relay with hysteresis and switches force acting on the object in relation to its velocity. Such nonlinear control induces a limit cycle in the feedback system. The mass of the object is determined from the period of this limit cycle. The apparatus manufactured for experimental study uses two voice coil motors (VCM's), one of which is for driving the object and the other is for generating prescribed disturbances. The effects of system parameters and disturbances on measurement accuracy were examined experimentally.

Mass Measurement System Using Relay Feedback with Hysteresis

A review of mass measurement under weightless conditions is presented. Various measurement methods are listed with comments on the problems of several conventional methods. It is followed by a summary of the works conducted by the author.

Devices for mass measurement under weightless conditions

A review of mass measurement devices developed by the author is presented. According to the measurement principles, the treated devices are classified into two types. The first type uses a dynamic vibration absorber as a device for both mass measurement and vibration control. The main advantage is no vibration transmitted into the surrounding structures during measurement. The second type uses relay feedback. The advantages are simpler mechanism and robustness against disturbances. In this article, the principles of measurement of each type are presented.

Development of Mass Measurement Devices for Zero-Gravity Experiments

This paper treats a relay-feedback mass measurement system that uses a relay with hysteresis and feeds back the velocity of the object. The efficacy of the proposed method has been already confirmed experimentally. In actual measurement, however, a spring-like element must be added for avoiding the drift of the object. The effect of this spring on mass estimation has not been investigated analytically. In this paper, an estimating equation including this effect is derived. The derived equation indicates that the estimated mass is smaller than the actual value when the conventional estimating equation is used. The experiments carried out in the fabricated apparatus support well the validity of the derived estimating equation.

Analysis on the effect of stiffness on mass measurement using a relay feedback of velocity

http://www.nt.ntnu.no/users/skoge/prost/proceedings/ifac2008/data/papers/0359.pdf

Mass Measurement under Weightless Conditions by Relay Feedback Systems

Concerns mass measurement under conditions of weightlessness. A mass measurement system using the self-excited oscillation of a nonlinear system is developed. The system contains an on-off relay with dead zone and switches force acting on the object in relation to the position. The mass of the object is determined from the time interval measurement of the on-state and off-state periods. The measurement accuracy is experimentally studied.

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M. Takeuchi

Papers

Mass measurement using a system containing an on-off relay with dead zone