An Alternative Stability Proof for Direct Adaptive Function Approximation Techniques Based Control of Robot Manipulators

This short note points out an improvement on the robust stability analysis for electrically driven robots given in the paper. In the paper, the author presents a FAT-based direct adaptive control scheme for electrically driven robots in presence of nonlinearities associated with actuator input constraints. However, he offers not suitable stability analysis for the closed-loop system. In other words, it does not consider the role of saturation function in both control design and stability analysis.