A Bifurcated Gain Adaptation Strategy in Sliding Mode Control with Chattering Alleviation for High Fidelity Operations

This work proposes a new gain adaptation strategy for sliding mode controller (SMC) employed in high fidelity operations. This research work derives an important condition for the proposed law to achieve chattering reduction without compromising system robustness. In the process, it compares an existing adaptive gain strategy with the proposed law in terms of chattering, accuracy and robustness. Further, it discusses the rationale behind the selection of the SMC reaching law used in the paper that is different from the existing strategy. Also, the proposed strategy is implemented and tested for its performance in a commercial unmanned aerial vehicle (UAV), for brick wall construction that requires good level of accuracy and robustness. During implementation, it considers practical constraints of the physical system such as actuator bandwidth, sensitivity and saturation limits. From a pragmatic perspective, this work also provides a detailed discussion on the selection and tuning of controller parameters with respect to the physical system limits and desired performance criteria set by the user.