Analysis of servo-constraints solution approaches for underactuated multibody systems

The servo-constraints approach is an efficient method for computing inverse models of underactuated multibody systems. Underactuated multibody systems possess more degrees of freedom than independent control inputs. The inverse model can be used as a feedforward controller in a two degree of freedom control structure. Servo-constraints constrain the output to a specified trajectory and happend the equations of motion to form a set of differential-algebraic equations (DAEs). The resulting DAEs might be of higher differentiation index and are thus difficult to solve numerically. Here, different solution and analysis methods for the servo-constraints approach are compared. Especially, various solvers are analyzed with respect to real-time capability and accuracy.