Page 31 - ASME DSCC 2015 Program

Technical Program

combined optimal design and control of a Near Isothermal Liquid A Control Strategy for an Active Alignment Transtibial Prosthesis
Piston Air Compressor/expander for a Compressed Air Energy Storage Invited session paper. DSCC2015-9948
(caes) System for Wind Turbines Andrew laPre, frank Sup, University of Massachusetts Amherst, Amherst,
Invited session paper. DSCC2015-9957 MA, United States
Mohsen Saadat, Perry Y. li, University of Minnesota, Minneapolis, MN, This paper presents a control approach for an experimental transtibial prosthesis
United States
that can actively realign the residual limb in relation to prosthetic foot during the
The key component of a Compressed Air Energy Storage (CAES) system stance phase of gait. The realignment objective is to inject positive power into the
is the air compressor/expander. The roundtrip efficiency of this energy gait cycle while actively reducing the magnitude of the sagittal moment trans-
storage technology highly depends on the efficiency of the air compressor/ ferred to the residual limb. The altered gait dynamics of this new type of prosthe-
expander. Decreasing compression/expansion time Increases power-den- sis require a control approach that coordinates its function with a user’s gait cycle.
sity which reduces cost. There is a trade off between the thermal efficiency This paper overviews the mechanical design of the prosthesis development, the
and power density of this component. Different ideas and approaches were proposed finite-state adaptive controller, and presents experimental results for
introduced and studied in the previous works to improve this trade off by constant cadence walking and adaptation while changing walking speeds
enhancing the heat transfer between air and its environment. In the present
Wheel-slip Based Inverse Solution for differential drive Mobile robots
work, a combination of optimal compression/expansion trajectories, optimal
Invited session paper. DSCC2015-9854
chamber shape and optimal heat exchanger material distribution in the
chamber is considered to maximize the power density of a compression/ alan Whitman, garrett clayton, alex poultney, hashem ashrafiuon,
Villanova University, Villanova, PA, United States
expansion chamber for a given desired efficiency. Results show that the
power density can be improved by more than 20 folds if the optimal combi- An approximate inverse dynamic solution for differential drive mobile robots
nation of flow rate, shape and porosity are used together. is presented where the wheel speeds are analytically calculated for a spec-
ified desired trajectory. The differential equations of motion of the mobile
InVITED SESSIon robot are nondimensionalized and a small parameter is defined based on
2-20-1 WM5 Control of Robotic Systems the ratio of wheel slip and wheel speed variation time scales. Approximate
Emerson Burkhart A 1:30pm–3:30pm
dominant and first order inverse solutions are derived for general trajecto-
ries. Next, a trajectory planning strategy is devised to ensure continuous
Session Organizer: Kevin fite, Clarkson University wheel speed profiles in achieving any desired target trajectory. The case of
Session Organizer: Mo Rastgaar, Michigan Technological University target circular trajectories is specifically considered and with inverse solu-
Session Organizer: frank Sup, University of Massachusetts, Amherst tions which are verified both through simulations and experiments.
Session Organizer: Robert Gregg, University of Texas, Dallas
Session Chair: Jim Dabney, University of Houston-Clear Lake Trajectory Tracking of a Pendulum-Driven Spherical Robot
Contributed regular paper. DSCC2015-9727
Session Co-Chair: hashem ashrafiuon, Villanova University
francois R. Hogan, McGill University, Montreal, QC, Canada,
Torque estimation in a Wrist rehabilitation robot using a Nonlinear James R. forbes, University of Michigan, Ann Arbor, MI, United States
Disturbance observer
In this paper, a controller is designed to achieve tracking of a pendu-
Invited session paper. DSCC2015-9717
lum-driven spherical robot about a desired trajectory in the presence of
Mohammadhossein Saadatzi, David C. long, Colorado School of Mines, model uncertainty and external disturbances. A methodology is proposed to
Golden, CO, United States, ozkan Celik, Colorado School of Mines, XX, CO, design a feedforward controller for the spherical robot by approximating the
United States
desired trajectory using circles as basis functions. A linear state-feedback
In this paper, we present implementation of a nonlinear disturbance controller is used to drive the perturbations from the desired trajectory to
observer algorithm to estimate disturbance torques on a wrist rehabilitation zero. Numerical simulations show that the controller realizes tracking of the
robot. The ultimate goal is to enable accurate estimation of user interaction desired trajectory with perturbed initial conditions.
torques without force/torque sensors. A dynamic model of the Wrist Gimbal
Complete Dynamic Modelling of flexible Joint Robots
two degree-of-freedom forearm and wrist exoskeleton is developed. A non
Contributed short paper. DSCC2015-9813
linear disturbance observer (NDO) algorithm that incorporates the robot
yu Zhao, xiaowen yu, Masayoshi Tomizuka, University of California,
dynamics is implemented. Friction models for both joints of the robot are
Berkeley, CA, United States, Cong Wang, New Jersey Institute of
identified. The robot dynamic model and the accuracy of the disturbance
Technology, Newark, NJ, United States
torque estimations are experimentally verified under closed-loop trajectory
tracking scenarios. Joint flexibility is common in industrial robots that have geared joints. In order
to design a precision motion controller that compensates the effects of joint
elasticity, an accurate dynamic model of flexible joint robots is required. The
models that are commonly used ignore the gyroscopic interactions be-
tween the motors and links. In order to evaluate the influence of the ignored
gyroscopic interaction, a complete dynamic model for flexible joint robots is
derived in this paper. It is shown that when to realize high accuracy for high
velocity trajectory tracking, the motor inertia is non-negligible compared to link 31
inertia, and that the neglected interaction terms must be taken into account.