  Chinese calligraphy is a unique art form with great artistic value but
difficult to master. In this paper, we formulate the calligraphy writing
problem as a trajectory optimization problem, and propose an improved virtual
brush model for simulating the real writing process. Our approach is inspired
by pseudospectral optimal control in that we parameterize the actuator
trajectory for each stroke as a Chebyshev polynomial. The proposed dynamic
virtual brush model plays a key role in formulating the objective function to
be optimized. Our approach shows excellent performance in drawing aesthetically
pleasing characters, and does so much more efficiently than previous work,
opening up the possibility to achieve real-time closed-loop control.
