Abstract: An active-constraint robot (4), particularly for surgical use, is controlled by means of a series of motorized joints to provide a surgeon with real-time tactile feedback of an operation in progress. The robot system holds, in memory, a series of constraint surfaces beyond which it would be dangerous for the surgeon to go, and a resistive force is applied to the cutting tool (14) as the surgeon approaches any such surface. To improve the overall quality of feedback experienced by the surgeon, the resistive force applied to the cutting tool (14) depends upon the point of intersection (I) between the force factor applied by the surgeon and the surface. Further improvements are achieved by adjusting the tangential resistive force, when the tool is adjacent to the surface, in dependence upon the surrounding shape of the surface.

Abstract: An active-constraint robot (4), particularly for surgical use, is controlled by means of a series of motorised joints to provide a surgeon with real-time tactile feedback of an operation in progress. The robot system holds, in memory, a series of constraint surfaces beyond which it would be dangerous for the surgeon to go, and a resistive force is applied to the cutting tool (14) as the surgeon approaches any such surface. To improve the overall quality of feedback experienced by the surgeon, the resistive force applied to the cutting tool (14) depends upon the point of intersection (I) between the force factor applied by the surgeon and the surface. Further improvements are achieved by adjusting the tangential resistive force, when the tool is adjacent to the surface, in dependence upon the surrounding shape of the surface.

Abstract: The invention in its various forms relates generally to surgical planning methods, and in particular to the planning of surgical operations to implant a prosthesis. In a first embodiment, the surgeon uses an interactive system to design both the shape of the prosthesis and the shape of the bone. In a second embodiment, a modified Marching Cubes algorithm is used to simulate cutting planes within bones. In a third embodiment, back-projection is used within a computer model to allow an integrated display of both bone and prosthesis. In a fourth embodiment, an interactive system is used to test the mobility of a proposed implant, prior to undertaking a surgical operation.