What I did: measure transfer function of Roberts linkages.
I measured transfer function of Roberts linkages.
I attacehd two transfer function.
Resonant frequency are set at 1.5Hz(Fig 1, 2) and around 0.5Hz(Fig 3, 4) respectively.
The set up of these experiments are also attached.
The experiment whose resonant frequency is set at 1.5Hz probably have peak at 1.5Hz(Fig 1).
The peak on experiment whose resonant frequency is set around 0.5Hz is 3Hz(Fig 3). This peak is yaw motion.
The reason that I didn't measure transfer function surrounding resonant frequency is the range of photo sensor.
I realized that when I measure the transfer function, I need to measure mutiple time.
What I will do: I will remeasure the transfer function whose resonat frequency is set around 0.5Hz.
I remeasured the transfer function whose resonant frequency is set around 0.5Hz.
I measured it from 2Hz to 0.1Hz.
The peak of resonant looks like 0.4Hz.
This time, peak of resonant is crushed by range of photo sensor.
When I measured it around resonant frequency, displacement is bigger than linear range of photo sensor.