Robotically controlled slosh-free motion of an open container of liquid

Robotically Controlled Slosh-Free Motion of an Open Container of Liquid John Feddema, Clark Dohrmann, Gordon Parker, Rush Robinett, Vicente Romero, Dan Schmittt Sandia National Laboratories Albuquerque, NM 87185 RECEIVED OCT 1 1 1995 Q S T I This paper describes two methods for controlling the surface of a liquid in an open container as it is being carried by a robot arm. Both methods make use of the fundamental mode of oscillation and damping of the liquid in the container as predicted from a boundary element model of the fluid. The fust method uses an infinite impulse response filter to alter an acceleration profile so that the liquid remains level except for a single wave at the beginning and end of the motion. The motion of the liquid is similar to that of a simsle pendulum. The second method removes the remaining two surface oscillations by tilting the container parallel to the beginning'and ending wave. A double pendulum dodel is used to determine the trajectory for this motion. Experimental results of a FANUC Sr800 robot ' moving a 230 mm diameter hemispheiical container of water are presented.