A robotic actuation system for sensorless force control of an interventional tool (14) having cable driven distal end (e.g., a probe, a steerable catheter, a guidewire and a colonoscope). The system employs a robotic actuator (30) having one or more motorized gears operate the cable drive of the interventional tool (14). The system further employs a robotic workstation (20) to generate motor commands for simultaneous actuation position and contact force control of the interventional tool (14). The motor commands are a function of an actuation position measurement and a motor current measurement of the at least one motorized gear for a desired actuation position of the interventional tool (14).