2.2.4.1. Introduction
Each patient-side da Vinci Si arm (PSM, ECM) is controlled by a single box. There is no dVRK support for the Si/Xi surgeon’s console (i.e. MTMs, foot pedals…).
Each controller is built around a single dRAC/FPGA stack. Both boards (dRAC and FPGA logic board) were designed at JHU. The dRAC board provided 10 PWM power lines for the PSMs and ECMs (7 motors and 3 brakes).
One main difference between the QLA and the dRAC is that the dRAC doesn’t need to process any low power signals since the embedded ESPM does. The ESPM converts all the low power signals (encoder, potentiometer, buttons, instrument Id, LEDs) and communicate with the dVRK controllers over a serial digital connection (LVDS). To communicate with the arm, the dVRK-Si controllers use two standard D-Sub connectors, one for the LVDS communication and one for the 10 power lines. The connectors are the same used in the PSMs and ECMs.
The dRAC also integrates the safety chain to further reduce the number of components. On the Classic controllers we rely on a separate safety relay.
All controllers come with FireWire and Ethernet interfaces, so they can be daisy-chained and communicate with a computer.
All Si controllers use a single FPGA board V3. See also controller versions.