No abstract

TRACZ -Testing Robotic Applications for Catching in Zero-g is a fully autonomous mechatronic experiment, launched on March 19, 2019, on board the REXUS rocket, during the 26th Campaign of the REXUS/BEXUS Programme. The main goal of the experiment was to investigate the jamming phenomenon in the space environment (microgravity and vacuum) as well as to construct a version of industry device known as jamming gripper, capable of operating in conditions where negative pressure (physical basis of operation in Earth-like conditions) cannot be obtained due to the presence of only a residual atmosphere. The structure was designed as 1-DOF manipulator, whose effector is an elastic membrane that stimulates jamming of ground coffee particles inside. During the suborbital flight, a series of catcheswere performed on a single object and the force with which the object is held was measured. The results were compared with an on-ground experiment.

This paper introduces a predictive closed-loop trajectory tracking algorithm for nonlinear control systems that combines the Model Predictive Control (MPC) approach with the task priority Lifted Newton method. The optimal control problem within MPC is replaced by the open-loop trajectory tracking problem formulated as a constrained motion planning problem. Constraints reflect the distance in the task space between the system current output and the desired trajectory. The original constrained motion planning problem is replaced by an unconstrained one addressed in an extended control system representation, and solved with the task priority version of the Lifted Newton method. All other steps of the MPC scheme remains unchanged. Performance of the closed-loop predictive Lifted Newton trajectory tracking algorithm has been demonstrated with series of computer simulations for the kinematic car type platform.