Nonlinear adaptive H∞ control of constrained robotic manipulators with input nonlinearity

The problem of constructing nonlinear adaptive H_infin control of constrained robotic manipulators with uncertain input nonlinearities such as dead-zone or backlash, is considered in this paper. In the proposed control scheme, adaptive inverse models are introduced to compensate effects of input nonlinearities, and the trajectory converges to the desired constrained trajectory, and the constraint force also follows the desired constraint one. The resulting control strategy is derived as a solution of certain H_infin control problem, where estimation errors of tuning parameters, errors of constraint forces and residual terms of the inverse models, are regarded as external disturbances to the process.