Table 1 Main dimensions and inertial Properties.
Parameters | Descriptions | Dimensions |
|---|---|---|
\(\:{L}_{l1},\:{L}_{l2}\) | Length of leg | \(\:{L}_{l1}=\:{L}_{l2\:}=250\text{m}\text{m}\) |
t, b | Aluminium beam cross-section | 1 mm * 25 mm |
\(\:{L}_{1},\:{L}_{2}\) | Length from feet to the centre of mass of leg | \(\:{L}_{1}=0.5{L}_{l1\:},\:{\:{L}_{2}=0.5L}_{l2}\) |
\(\:{m}_{1},\:{m}_{2}\) | Mass of leg | \(\:{\:m}_{1}=\:{m}_{2}\:=\:16.8\:\text{g}\text{r}\text{a}\text{m}\) |
\(\:{L}_{l3}\) | Spine length | \(\:{L}_{l3}=\:250\text{m}\text{m}\) |
\(\:{L}_{3}\) | \(\:\text{E}\text{q}\text{u}\text{a}\text{l}\:{L}_{l2}\:,\:{L}_{l2}\:\text{W}\text{h}\text{e}\text{n}\:{\theta\:}_{1}={\theta\:}_{2}\) | \(\:{L}_{3}={L}_{l1}\text{cos}{\theta\:}_{1}\:or\:{L}_{l2}\text{cos}{\theta\:}_{2}\) |
\(\:{m}_{3}\) | Mass of spine | \(\:{m}_{3}\:=\:16.8\:\text{g}\text{r}\text{a}\text{m}\) |
\(\:{k}_{L}\) | Longitudinal stiffness of the curved beam | 200 (N/m) |
\(\:{k}_{\theta\:1},\:{k}_{\theta\:2}\) | Torsional spring stiffens at spine | 4 (Nm/rad) |
µstick | Stiction friction coefficient, | 0.6 |
µslide | Sliding friction coefficient | 0.5 |
\(\:{\theta\:}_{f1},\:{\theta\:}_{f2}\) | Angle between leg and spine | \(\:{\theta\:}_{f1}=\:{\theta\:}_{f2}={\theta\:}_{f}=120^\circ\:\) |
\(\:{\theta\:}_{1},{\theta\:}_{2}\) | Angle between leg and final point of spine | \(\:{\theta\:}_{1}\ne\:{\theta\:}_{2}\) |
\(\:{d}_{\theta\:1},\:{d}_{\theta\:2}\) | Coefficient of damping | 0.01 (Nm, s/rad) |
\(\:{m}_{h},\:{m}_{f}\) | Mass of foot | \(\:{m}_{h}={m}_{f\:}=\:20\:\text{g}\text{r}\text{a}\text{m}\) |
\(\:{L}_{fr},\:{L}_{fl}\) | Right and Left foot length | \(\:{L}_{fr}=\:{L}_{fl}=\:150\text{m}\text{m}\) |
\(\:{m}_{M}\) | Mass of motor | 40 gram |
R | Radius of rotation | 50 mm |
\(\:{m}_{R}\) | Rotating mass | 0.025 kg |
