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.