An assembly of electrically-powered devices intended to be used for trajectory planning and positioning of interventional instruments during computer-assisted transperineal prostate biopsy and ablation procedures under image-guidance, using real-time ultrasound imaging and pre-acquired MRI scans. It consists of a software-assisted console with a screen interface and a robotic electromechanical arm designed to guide the surgical instrument (e.g., prostate needle) to the target site following the pre-planned path set by the physician.