The creation of dynamic manipulation behaviors for high degree of freedom, mobile robots will allow them to
accomplish increasingly difficult tasks in the field. We are investigating how the coordinated use of the body, legs, and
integrated manipulator, on a mobile robot, can improve the strength, velocity, and workspace when handling heavy
objects. We envision that such a capability would aid in a search and rescue scenario when clearing obstacles from a
path or searching a rubble pile quickly. Manipulating heavy objects is especially challenging because the dynamic forces
are high and a legged system must coordinate all its degrees of freedom to accomplish tasks while maintaining balance.
To accomplish these types of manipulation tasks, we use trajectory optimization techniques to generate feasible open-loop
behaviors for our 28 dof quadruped robot (BigDog) by planning trajectories in a 13 dimensional space. We apply
the Covariance Matrix Adaptation (CMA) algorithm to solve for trajectories that optimize task performance while also
obeying important constraints such as torque and velocity limits, kinematic limits, and center of pressure location. These
open-loop behaviors are then used to generate desired feed-forward body forces and foot step locations, which enable
tracking on the robot. Some hardware results for cinderblock throwing are demonstrated on the BigDog quadruped
platform augmented with a human-arm-like manipulator. The results are analogous to how a human athlete maximizes
distance in the discus event by performing a precise sequence of choreographed steps.