Feedback control of an underactuated system with two unactuated degrees of freedom

2003 ◽  
Author(s):  
M. Reyhanoglu
Keyword(s):  
Feedback Control ◽  
Degrees Of Freedom ◽  
Underactuated System

Trajectory Tracking of Underactuated Surface Vessels Based on Hierarchical Sliding Mode

2014 ◽  
Author(s):  
Cheng Liu ◽  
Zaojian Zou ◽  
Jianchuan Yin
Keyword(s):  
Trajectory Tracking ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Sliding Mode ◽  
Underactuated System ◽  
Sliding Mode Controller ◽  
Control Field ◽  
Surface Vessels ◽  
Underactuated Surface Vessels ◽  
Hierarchical Sliding Mode

Trajectory tracking is an importance practice in ship motion control field. It attracts more attention recently due to its difficulties. Trajectory tracking requires the ship to arrive pinpoint location at exact time. It is a underactuated system because the degrees of freedom of control inputs are fewer than the degrees of freedom that needed to be controlled. In this paper, a hierarchical sliding mode controller and a common sliding mode controller are proposed to deal with the trajectory tracking problem of underactuated surface vessels. Simulation results validate the tracking performance of the proposed controllers. The closed-loop stability is testified by the Lyapunov stability theorem.

Feedback control of the neuromusculoskeletal system in a forward dynamics simulation of stair locomotion

2009 ◽  
Vol 223 (6) ◽  
pp. 663-675 ◽  
Author(s):  
A Selk Ghafari ◽  
A Meghdari ◽  
G Vossoughi
Keyword(s):  
Feedback Control ◽  
Degrees Of Freedom ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Human Movement ◽  
Stair Climbing ◽  
Dynamics Simulation ◽  
Forward Dynamics ◽  
Control Loops ◽  
The Stability

The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of pressure during locomotion. The parameters of the proposed controller were determined by employing the iterative feedback tuning approach to minimize tracking errors during forward dynamics simulation. Simultaneously, an inverse-dynamics-based optimization was employed to compute a set of desired musculotendon forces in the closed-loop simulation to resolve muscle redundancy. Quantitative comparisons of the simulation results with the experimental measurements and the reference muscles' activities illustrate the accuracy and efficiency of the proposed method during the stable ascending simulation.

Impedance Control: An Approach to Manipulation: Part II—Implementation

1985 ◽  
Vol 107 (1) ◽  
pp. 8-16 ◽  
Author(s):  
Neville Hogan
Keyword(s):  
Feedback Control ◽  
Inverse Kinematics ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Impedance Control ◽  
Dynamic Interaction ◽  
End Point ◽  
Inverse Kinematics Problem ◽  
Theoretical Reasoning ◽  
Redundant Actuators

This three-part paper presents an approach to the control of dynamic interaction between a manipulator and its environment. Part I presented the theoretical reasoning behind impedance control. In Part II the implementation of impedance control is considered. A feedback control algorithm for imposing a desired cartesian impedance on the end-point of a nonlinear manipulator is presented. This algorithm completely eliminates the need to solve the “inverse kinematics problem” in robot motion control. The modulation of end-point impedance without using feedback control is also considered, and it is shown that apparently “redundant” actuators and degrees of freedom such as exist in the primate musculoskeletal system may be used to modulate end-point impedance and may play an essential functional role in the control of dynamic interaction.

Pointwise Optimal Control of Dynamical Systems Described by Constrained Coordinates

1999 ◽  
Vol 121 (4) ◽  
pp. 594-598 ◽  
Author(s):  
V. Radisavljevic ◽  
H. Baruh
Keyword(s):  
Optimal Control ◽  
Dynamical Systems ◽  
Feedback Control ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Differential Algebraic Equations ◽  
Control Law ◽  
Algebraic Equations ◽  
The Stability ◽  
The Mathematical Model

A feedback control law is developed for dynamical systems described by constrained generalized coordinates. For certain complex dynamical systems, it is more desirable to develop the mathematical model using more general coordinates then degrees of freedom which leads to differential-algebraic equations of motion. Research in the last few decades has led to several advances in the treatment and in obtaining the solution of differential-algebraic equations. We take advantage of these advances and introduce the differential-algebraic equations and dependent generalized coordinate formulation to control. A tracking feedback control law is designed based on a pointwise-optimal formulation. The stability of pointwise optimal control law is examined.

Position Control of an Underactuated Planar 2R Manipulator

2001 ◽  
Author(s):  
José A. Rosas-Flores ◽  
Jaime Alvarez-Gallegos ◽  
Rafael Castro-Linares
Keyword(s):  
Feedback Control ◽  
Optimization Algorithm ◽  
Position Control ◽  
Initial Conditions ◽  
Error Modeling ◽  
Underactuated System

Abstract In this paper the problem of regulation of an underactuated planar 2R manipulator is solved by tracking appropriate planned trajectories. A class of parametric trajectories is propossed to reach a desired configuration. The parameters of the trajectories are found by using an optimization algorithm. Besides, a feedback control is proposed to regulate the manipulator under error modeling and small desviations on the initial conditions. By using simulations, it is illustrated that if the coordinates of the underactuated system track the planned trajectories then the system reaches the desired configuration.

Dependent versus Independent Variable Formulation for the Dynamics and Control of Cranes

2009 ◽  
Vol 147-149 ◽  
pp. 221-230 ◽  
Author(s):  
Wojciech Blajer ◽  
Krzysztof Kołodziejczyk
Keyword(s):  
Degrees Of Freedom ◽  
Differential Algebraic Equations ◽  
Numerical Code ◽  
Underactuated System ◽  
Algebraic Equations ◽  
Underactuated Mechanical Systems ◽  
Performance Goal ◽  
Inverse Simulation ◽  
Simple Index ◽  
Simulation Problem

Cranes are underactuated mechanical systems with fewer control inputs than the degrees of freedom. Their usual performance goal is to execute a desired load trajectory, which is specified by as many outputs as the control inputs. A solution to the inverse simulation problem, in which the control of the underactuated system required to execute the partly specified motion is determined, is a challenging task. The inverse simulation study is usually formulated in independent variables. In this paper a dependent variable formulation is reported, advantageous in many aspects. The resultant governing equations appear as simple index-three differential-algebraic equations, and an effective numerical code for their solution is discussed.

Robust Adaptive Controller Design for a Quadrotor Helicopter

2013 ◽  
Vol 284-287 ◽  
pp. 2296-2300 ◽  
Author(s):  
Kuang Shine Yang ◽  
Chi Cheng Cheng
Keyword(s):  
Attitude Control ◽  
Degrees Of Freedom ◽  
Controller Design ◽  
Sliding Mode ◽  
Underactuated System ◽  
Parameter Uncertainties ◽  
Unknown Parameters ◽  
External Disturbances ◽  
Quadrotor Helicopter ◽  
Robust Adaptive

The quadrotor helicopter is designed to easily move in particular environments because it can take off and land in limited space and easily hover at a fixed location. For this reason, a robust adaptive sliding mode controller is developed to control of a quadrotor helicopter in the presence of external disturbances and parameter uncertainties. The quadrotor helicopter system is a typical underactuated system, which has fewer independent control actuators than degrees of freedom to be controlled. The main contribution here is to afford simulation and verification for the quadrotor helicopter flight controller under the assumption of unknown parameters. By utilizing the Lyapunov stability theorem, we can achieve asymptotic tracking of desired reference commands for the quadrotor helicopter, which is subject to both external disturbances and parametric uncertainties. From the simulation results, the controller was sufficient to achieve position and attitude control of the quadrotor helicopter system, which permits possible real time applications in the near future.

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