On safety enhancements for medical robots

Both software and hardware methods to enhance safety are discussed for active medical robots applied to, among others, neurosurgery, orthopaedic surgery and prostatectomy. This paper advocates that while it is practically difficult, if not impossible, for software reliability to be 100%, there are positive measures by which a medical robot system can be made adequately or inherently safe. Such measures avoid the problems of software reliability but turn to mathematical logic directly to build a safer system. Examples in a newly developed prototype, known as surgeon assistant robot for selected urological disorders (SARUD), are given to illustrate the concept. Although software measures to promote reliability of a system is less preferred compared to hardware measures, as it can never escape from operating on a hardware platform, it is suggested that a complementary/ hybrid approach can be a good solution for achieving a safe and flexible (by being reprogrammable) system. A totally independent safety monitor is being built. It can arrest a servo runaway and detect out-of-safe-boundary conditions, using encoder pulses as input. This dedicated system can resolve some major safety concerns of a medical robot such as SARUD.