Interconnection and damping assignment passivity-based control of mechanical systems with underactuation degree one

Published versio

Energy-based swing-up of the acrobot and time-optimal motion

We present a control law for the swing-up of an acrobot with torque constraints on the actuator. The domain of the initial condition for the strategy to work is the entire manifold and we further guarantee that the system reaches a small neighbourhood about the upward equilibrium position. For a restricted domain of the initial condition, we observe that the control law is bang-bang in nature. This motivates us to verify the time-optimality of the control strategy. Necessary conditions for time-optimality are presented and these are subsequently verified numerically

Controllability properties of a planar 3R underactuated manipulator

In this paper we present a few controllability properties of a three link planar, horizontal underactuated manipulator with three revolute joints (3R) and two control inputs. The controllability analysis is presented for various actuator configurations. In particular, it is shown that the system is small time locally controllable (STLC) for all except one of the configurations

A swing-up of the acrobot based on a simple pendulum strategy

We propose a control law to swing-up the acrobot from an initial domain to a neighbourhood of the vertically upward equilibrium position. The methodology involves reducing the system to a one degree-of-freedom system, much like a simple pendulum, evolving on a critical value of the energy level set. The system is guaranteed to converge to a neighbourhood of the upward equilibrium position about which a linear feedback controller is switched on to stabilize the system

A non-smooth control law and time-optimality notions for the acrobot

We propose a discontinuous control law to pump energy into the acrobot system to place the system at a certain energy level. Filippov calculus is used to establish convergence of the system trajectory to the desired energy set. The bang - bang nature of the control law prompts us to investigate whether the energy is pumped in minimum time. We then present necessary conditions for time optimality

Controllability and point-to-point control of 3-DOF planar horizontal underactuated manipulators

This paper presents the controllability properties of an underactuated 3R manipulator and the application of a discontinuous point-to-point control law for a three-degree-of-freedom (DOF) PPR manipulator. In the first half we present a controllability analysis at various actuator configurations of the manipulator. A novel contribution is that we use a single coordinate system to analyse the controllability at all the three possible configurations. In the second half we present a discontinuous feedback control law for point-to-point control of a 3 DOF PPR underactuated manipulator moving in a horizontal plane. Simulation results are presented that demonstrate the effectiveness of the controller

Active noise cancellation using H∞ control techniques

The noise cancellation problem has been studied extensively. Low frequency (acoustic) noise attenuation has faced attention in industrial environments and in automobile applications. The modeling of the one-dimensional case (where sound travels in a duct and hence between 'wave guides') is relatively straightforward for example. In this paper, a laboratory experimentation of canceling noise using the H/sub /spl infin// control algorithm is presented. The setup consists of a rectangular wooden duct fitted with speakers (for actuation and noise) and microphones (for sensing). The system is interfaced to a stand-alone DSP board (dSPACE) with a TMS 320C31 chip and the control algorithm is implemented digitally on the DSP.© IEE

A switched finite-time point-to-point control strategy for an underactuated underwater vehicle

We present a switched finite-time control law for the point-to-point control of an underactuated underwater vehicle (UUV) moving in a horizontal plane in a neutrally buoyant condition. The control law consists of a sequential series of control actions, each of which achieves a certain objective, finally resulting in the system being moved to the origin. The methodology is demonstrated for one of the possible three actuator configurations.© IEE

A switched controller for an underactuated underwater vehicle

We present a switched control law for stabilizing an underactuated underwater vehicle (UUV) moving in a horizontal plane in a neutrally buoyant condition. The control law consists of a sequential series of control actions, each of which achieves a certain objective, finally resulting in the system being moved to the origin. Finite-time controllers are employed at each stage to achieve the desired objective. Simulation results are presented to validate the control law. (c) 200

Discontinuous feedback control of A 3 link planar PPR underactuated manipulator

In this paper we consider the synthesis of a point-to-point control law for a three degrees of freedom planar PPR underactuated manipulator moving in a horizontal plane. We apply the results of [1] where a discontinuous feedback controller construction for a special class of underactuated systems is presented. By using a coordinate transformation provided by [2] we transform the system into chained form which makes it suitable for the application of the discontinuous control law. Simulation results are presented that demonstrate the effectiveness of the controller