Table 1: Definitions of system variables and parameters.

: mass of link 1 (0.056 kg)   : mass of link 2 (0.022 kg)   : length of link 1 (0.16 m)   : length of link 2 (0.16 m)   : distance to link 1 center of mass (0.08 m)   : distance to link 2 center of mass (0.08 m)   : inertia of link 1 (0.001569 kg·m2)   : inertia of link 2 (0.001785 kg·m2)   : displacement of link 1   : angular velocity of link 1   : displacement of link 2   : angular velocity of link 2   : applied torque