Development of different (kinematic and dynamic) control schemes for the Quattro S650 parallel manipulator. These controllers were implemented in the simulator of the robot. Extensive simulations were conducted for different scenarios and simulation conditions.       

With the kinematic calibration, we improve the precision of our robot of 65%, considering 33 parameters to describe the Quattro robot. The study of the sensibility of each parameter allows us to suppress some of them without interfering with the results quality. With 25 parameters we obtain 60% of improvement and with 21, 56%.

We wish to investigate the influence of the sampling of the calculation of the Quattro Jacobian on an adaptative control law. For the same trajectory simulation and the same set of Cartesian gains, we studied the influence of various Jacobian computation frequencies. For a frequency higher than 200 Hz, the system remains stable but below 200 Hz, the system does not response correctly anymore. We suspect the low frequency of the Jacobian computation to be one cause of the instability of the control.

The first step was an improvement of the duration of the computation of the Jacobian matrix. The second step was to to interpolate the Jacobian coefficients.

The Jacobian is now competed at the highest frequency as allowed with the current CPU load. The micro-interpolation of the Jacobian at 8 kHz has finally allowed solving some instability problems.