This movie demonstrates a prototype for a telesurgical system that provides reliable force feedback. Such a teleoperation system consists of a master, i.e. a haptic joystick, at one side and the slave, i.e. the surgical robot, at the other side. To realize stable and transparent force feedback, a mechatronic approach is mandatory: both the hardware and the controller have to be optimized through an integrated approach.
The OROCOS software was used to implement the controller on a Linux computer with a preemptible kernel patch. The master device and the ATI force sensors are interfaced with Beckhoff EtherCAT terminals, using the SOEM drivers library integrated in OROCOS, while the slave is interfaced with a National Instruments PCI-card (NI PCI-6221) using the Comedi drivers library. Both the master and slave are controlled by an OROCOS-component that is updated at 5 kHz. This high sampling rate was necessary to optimize the performance of the slave's local position controller. The master and slave-component communicate position and force information over OROCOS-ports at the same rate.
Bert is now writing up his PhD and will release more information about his experiences and the setup when he can free up some time.