Iterative Learning without Reinforcement or Reward for Multijoint Movements: A Revisit of Bernstein's DOF Problem on Dexterity

Figure 8

A handwriting robot with four DOFs whose endpoint $P$$(=(x,y,z))$ is constrained on a hypersurface $\phi (\mathbf{x})=0$, where $\phi (\mathbf{x})$ is a scalar function of $C^{\infty }$-class.