Mass Measurement Using a System Containing an On-Off Relay with Dead Zone

Adachi

et al. 2008

JSDD

Self Cite

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.

Section: Measurement Errorsmentioning

confidence: 92%

Section: Journal Of System Design and Dynamicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Mass Measurement System Using Relay Feedback with Hysteresis

Adachi

et al. 2008

JSDD

Self Cite

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

Ishino

2008 SICE Annual Conference

2008

Self Cite

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.

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

Egawa

Measurement and Control

et al. 2021

Self Cite

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.