Globally exponentially convergent velocity observer design for mechanical systems with nonholonomic constraints

In this article, a novel globally exponentially convergent velocity observer for a class of mechanical systems with l nonholonomic constraints is presented. Through using a special coordinate transformation, the constrained system is converted into the integral cascade Euler–Lagrange form, which could avoid solving partial differential equations and eliminate the influence of the constraint force when reconstructing the speed information. The proposed observer has a simple structure and lower dimensions compared with other globally exponentially stable observers by using dynamic scaling and gain filtering. The simulation results demonstrate the stability and effectiveness of proposed reduced-dimensional observer.