02 Delta (δ)
  • Date of Fabrication
    March 2002


    • Photo of 02 delta

    Description

    02-delta was one of the attempts at making a 1 DOF fourbar with the requirements:
    1. resonant frequency ≥ 150 Hz
    2. Amplitude at resonance ≥ 120 degrees
    3. Q ≤ 3
    The main changes in 02-delta over previous versions were a simplified slider crank which was supposed to cut down on parallel stiffness and a lighter fourbar inertia after it was calculated that a fourbar actually contributed close to 13 mg-mm^2 to the total inertia. In order to bring down the fourbar inertia, the fourbar was made out of 6 micron steel shim, which was made by first cutting out the template on normal 12 micron steel shim and then dunking it in FeCl3 for about 2 minutes which removed 50% of the mass. (Because of uneven texture, the thickness of the etched still still remained about 10 microns).

    Fabrication Parameters

    Fourbar Dimensions
    See solidworks drawings for complete dimensions.     		Link lengths (mm) 6, 6, 6, 1
    Flexure lengths (μm) 50, 50, 112.5, 112.5
    Flexure widths (mm) 3,2,2,2.5
    Slider crank dimensions Attachment point (mm) 1.8
    Actuator parameters Dimensions (mm) (10 + 6) x 3
    Serial Number 02-24-02-02M
    DC displacements (μm @ 150V) 256
    Stiffneses (N/m) 142
    Blocking force (mN @ 150V) 44
    Resonant Frequency (Hz)
    Q (= Xac/Xdc*150/Vac) 18.6, 21.76

    Performance Parameters

    DC displacement of output link (degrees @ 200V) 37 degrees
    DC displacement of actuator (microns @ 150V) 197
    Resonant frequency (Hz) 155
    AC displacement (degrees @ 100 ±100V) 130 degrees
    Q (calculated as θ(AC)/θ(DC) 3.51
    Estimated Serial Stiffness (N/m) 400