Flatness-based control in successive loops for dual-arm robotic manipulators

In this article, a multi-loop flatness-based controller is proposed for the dynamic model of a dual-arm robot. The control problem for this robotic system is solved with the use of a flatness-based control approach which is implemented in successive loops. To apply the multi-loop flatness-based control scheme, the state-space model of the dual-arm robotic manipulator is separated into subsystems, which are connected in cascading loops. Each one of these subsystems can be viewed independently as a differentially flat system and control about it can be performed with inversion of its dynamics as in the case of input-output linearized flat systems. The state variables of the subsequent (i + 1)-th subsystem become virtual control inputs for the preceding i-th subsystem. In turn, real control inputs are applied to the last subsystem. The whole control method is implemented in successive loops and its global stability properties are also proven through Lyapunov stability analysis.