In the period of reference (February 2011-March 2011) the following sub-tasks have been continued/initiated, according to the TESBE workplan:

• T 1.1: Review of the existing force control approaches
• T2.1: Mathematical formulation of the collaborative control strategy
• T3.2: Analysis and preliminary design of the under-actuated gripper mechanism

In sub-task 1.1 the continuation of the analysis of the SoA , in the field of control of robots interacting with humans ad unstructured environment, has allowed to identify more detailed methodologies for the system evaluation of the performances and stability of extenders intended for the handling of heavy loads, new control techniques and design methodologies able to guarantee a passive behavior of the interacting robots and new techniques and methodologies applicable to the design and development of motion controller of robots having elastic joints.

In sub-task 2.1 the algorithm and all associated mathematical methods required to implement the strategy for the collaborative control of the Body Extender posture have been defined. In particular the distortion of the vector in the n-dimensional space of the BE DoFs, representing the user intended motion, has been defined in terms of continuous reduction of the norm of the component producing a decrease of the distance of the Zero Moment Point from the support polygon, while leaving the orthogonal component unmodified. The mathematical methods required to find out the direction of projection of the user intended motion has been also defined.

In sub-task 3.2, the link lengths of the mechanism of the three fingers equipping the gripper have been preliminary dimensioned, taking as input the geometry of the objects to be grasped, as specified in sub-task 3.1.  Furthermore a new differential mechanism able to drive the three fingers using only one motor has been conceived to be integrated in the tight mechanics of the gripper. Finally the mechanical transmission from the output axis of the actuator unit to the input link of the differential mechanism has been also defined. All the main mechanical components of the finger and differential mechanisms and of the mechanical transmission have been preliminary dimensioned.