Figure 5.

Effect of passive stiffness on force feedback. Contours representing ${\beta }_0^{\text{effective}}/{\beta }_0^{\text{Land}}=1$ and ${\beta }_1^{\text{effective}}/{\beta }_1^{\text{Land}}=1$ were calculated (see Fig. 3, b and c) for a range of values of the passive stiffness a (Eq. 1) equal to (a) $0.25\times$, (b) $0.5\times$, (c) $1.0\times$, and (d) $2.0\times a_0$, where $a_0=2.1\mathrm{kPa}$ is the reference stiffness value specified in the Land model (39). The coordinate values $k_{\text{force}}^{\text{intx}}$ and $K_{\text{OFF}}^{\text{intx}}$ of the intersection point are plotted in (e) and (f), respectively, as functions of $a/a_0$.