Figure 8.

Control schemes of impedance and propulsion/resistance control. (a) Overview. (b) Controller diagram. Xⁿ, ${\dot{X}}^{\mathrm{n}}$, ${\ddot{X}}^{\mathrm{n}}$, and F_extⁿ are calculated by the strategy based on orthogonal deviation (Figure 7), and F^t denotes propulsion/resistance force.