Before revision: Furthermore, the dynamics for these systems can be rewritten to be affine in the control inputs: When expressed in this form, the system is said to be underactuated if: When this condition is met, there are acceleration directions that can not be produced no matter what the control vector is.
After revision: in many casesFurthermore, the dynamics for these systems can be rewritten to be affine in the control inputs: When expressed in this form, the system is said to be underactuated if: When this condition is met, there are acceleration directions that can not be produced no matter what the control vector is.