A translational oscillator with a rotational actuator (TORA) is an underactuated nonlinear mechanical system two degrees of freedom (DOF). This paper concerns the robust stabilization control problem for multiple external disturbances. First, disturbance observer constructed based on internal dynamic behavior system. Second, controller designed by estimated disturbances and fixed-time sliding m...

ontrol of underactuated biped robots is one of the challenging problems in the robotics field. The main difficulties of this problem that make it hard to control are its highly nonlinear dynamics, open-loop instability and impact event at the end of each step. Partial feedback linearization is a method to control underactuated systems but it is not robust against uncertainties and disturbances....

This paper investigates the possibility of converting grasped objects from precision grasps to power grasps using a variable transmission ratio for an underactuated finger. To this effect, a variable radius pulley was designed. A simulation study is presented to analyse grasping behaviour and a potential energy method is used to predict the equilibrium positions of finger and object. With this ...

A recent approach to the control of underactuated systems is to look for control laws which will induce some specified structure on the closed loop system. This basic idea is used in [1-9]. In this paper, we will describe one matching condition and an approach for finding all control laws that fit the condition. After an analysis of the resulting control laws for linear systems, we will present...

ontrol of underactuated biped robots is one of the challenging problems in the robotics field. The main difficulties of this problem that make it hard to control are its highly nonlinear dynamics, open-loop instability and impact event at the end of each step. Partial feedback linearization is a method to control underactuated systems but it is not robust against uncertainties and disturbances....

This paper deals with the inverse dynamics problem of underactuated mechanical systems subjected to execute partly specified motions. The modeling methodology focuses on a special class of differentially flat systems, represented by a group of relevant technical examples. The governing equations are obtained as index three differential-algebraic equations, and a simple numerical code for their ...

Abstract—The problem of finding control laws for underactuated systems has attracted growing attention since these systems are characterized by the fact that they have fewer actuators than the degrees of freedom to be controlled. The acrobot, which is a planar two-link robotic arm in the vertical plane with an actuator at the elbow but no actuator at the shoulder, is a representative in underac...

This paper builds off of recent work on rapidly exponentially stabilizing control Lyapunov functions (RES-CLF) and control Lyapunov function based quadratic programs (CLFQP) for underactuated hybrid systems. The primary contribution of this paper is developing a robust control technique for underactuated hybrid systems with application to bipedal walking, that is able to track desired trajector...

The control of nonholonomic and underactuated systems with symmetry is illustrated by the problem of controlling a bicycle. We derive a controller which, using steering and rear-wheel torque, causes a model of a riderless bicycle to recover its balance from a near fall as well as converge to a time parameterized path in the ground plane. Our construction utilizes new results for both the deriva...