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Full-Text Articles in Robotics
Dynamic Modeling, Parameter Estimation And Control Of A Leg Prosthesis Test Robot, Hanz Richter, Daniel J. Simon, William A. Smith, Sergey Samorezov
Dynamic Modeling, Parameter Estimation And Control Of A Leg Prosthesis Test Robot, Hanz Richter, Daniel J. Simon, William A. Smith, Sergey Samorezov
Electrical and Computer Engineering Faculty Publications
Robotic testing can facilitate the development of new concepts, designs and control systems for prosthetic limbs. Human subject test clearances, safety and the lack of repeatability associated with human trials can be reduced or eliminated with automated testing, and test modalities are possible which are dangerous or inconvenient to attempt with patients. This paper describes the development, modeling, parameter estimation and control of a robot capable of reproducing two degree-of-freedom hip motion in the sagittal plane. Hip vertical displacement and thigh angle motion profiles are applied to a transfemoral prosthesis attached to the robot. A treadmill is used as walking …
Fuzzy Robot Controller Tuning With Biogeography-Based Optimization, George Thomas, Paul Lozovyy, Daniel J. Simon
Fuzzy Robot Controller Tuning With Biogeography-Based Optimization, George Thomas, Paul Lozovyy, Daniel J. Simon
Electrical and Computer Engineering Faculty Publications
Biogeography-based optimization (BBO) is an evolutionary algorithm (EA) based upon the models of biogeography, which describe the relationship between habitat suitability and the migration of species across habitats. In this work, we apply BBO to the problem of tuning the fuzzy tracking controller of mobile robots. This is an extension of previous work, in which we used BBO to tune a proportional-derivative (PD) controller for these robots. We show that BBO can successfully tune the shape of membership functions for a fuzzy controller with both simulation and real world experimental results.
Globally Optimal Periodic Robot Joint Trajectories, Daniel J. Simon
Globally Optimal Periodic Robot Joint Trajectories, Daniel J. Simon
Electrical and Computer Engineering Faculty Publications
This paper presents a new method for the planning of robot trajectories. The method presented assumes that joint-space knots have been generated from Cartesian knots by an inverse kinematics algorithm. The method is based on the globally optimal periodic interpolation scheme derived by Schoenberg, and thus is particularly suited for periodic robot motions. Of all possible periodic joint trajectories which pass through a specified set of knots, the trajectory derived in this paper is the ‘best’. The performance criterion used is the integral (over one period) of a combination of the square of the joint velocity and the square of …
The Application Of Neural Networks To Optimal Robot Trajectory Planning, Daniel J. Simon
The Application Of Neural Networks To Optimal Robot Trajectory Planning, Daniel J. Simon
Electrical and Computer Engineering Faculty Publications
Interpolation of minimum jerk robot joint trajectories through an arbitrary number of knots is realized using a hardwired neural network. Minimum jerk joint trajectories are desirable for their similarity to human joint movements and their amenability to accurate tracking. The resultant trajectories are numerical rather than analytic functions of time. This application formulates the interpolation problem as a constrained quadratic minimization problem over a continuous joint angle domain and a discrete time domain. Time is discretized according to the robot controller rate. The neuron outputs define the joint angles (one neuron for each discrete value of time) and the Lagrange …
Suboptimal Robot Joint Interpolation Within User-Specified Knot Tolerances, Daniel J. Simon, Can Isik
Suboptimal Robot Joint Interpolation Within User-Specified Knot Tolerances, Daniel J. Simon, Can Isik
Electrical and Computer Engineering Faculty Publications
Approximation of a desired robot path can be accomplished by interpolating a curve through a sequence of joint-space knots. A smooth interpolated trajectory can be realized by using trigonometric splines. But, sometimes the joint trajectory is not required to exactly pass through the given knots. The knots may rather be centers of tolerances near which the trajectory is required to pass. In this article, we optimize trigonometric splines through a given set of knots subject to user-specified knot tolerances. The contribution of this article is the straightforward way in which intermediate constraints (i.e., knot angles) are incorporated into the parameter …