8. Experiments

8.1 Trajectories tested

The trajectory used for the control tests involves movement in the same direction for all three X-joints. This movement seems to be the most interesting for accessing a large workspace with reasonable forces. Starting from the straight configuration, the manipulator moves to α ^d = [50°, 50°, 50°] ^T , returns to the straight configuration, then moves to α ^d = [–30°, –40°, –50°] ^T , and finally returns to the straight configuration. All the desired joint configurations are linked by cycloidal functions. The four main trajectory configurations are shown in figure