Mechanical interface having multiple grounded actuators

An interface apparatus for interfacing motion of a user manipulable object with a computer system, said interface apparatus comprising:

• a user manipulable object being physically contacted by a user;
• a linkage of a plurality of members coupled to said user manipulable object, wherein said object has first and second degrees of freedom provided by said linkage;
• a rotatable carriage coupled between said linkage and a ground, said rotatable carriage providing a third degree of freedom to said user manipulable object;
• first, second, and third actuators coupled to said ground and operative to provide forces in said three degrees of freedom in response to actuator signals from said computer system;
• and
• a plurality of sensors, at least one of said sensors coupled to said linkage and at least one of said sensors coupled to said rotatable carriage, said sensors sensing a position of said object in said three degrees of freedom and outputting sensor signals to said computer system.

A mechanical interface apparatus for interfacing motion of a user manipulable object with a computer system, said interface apparatus comprising:

• a user manipulable object being physically contacted by a user;
• a 3-D spatial mechanism coupled to said user object and including a plurality of members including a ground member rigidly coupled to a ground, said spatial mechanism providing at least three degrees of freedom to said user manipulable object;
• three actuators rigidly coupled to said ground member of said spatial mechanism, said actuators operative to apply forces in said three degrees of freedom to said user manipulable object in response to electrical signals from said computer system, said three actuators being decoupled in force from each other such that none of said actuators can apply a force to any of said other actuators;
• and
• a sensor for detecting a position of said user manipulable object in three-dimensional space and outputting sensor signals to said computer system.

A mechanism for providing computer-controlled forces on a user manipulable object, the mechanism comprising:

• a user manipulable object graspable by a user;
• an actuator coupled between a ground surface and said user manipulable object and being controllable to provide a force in a degree of freedom of said user manipulatable object;
• a capstan drive coupled between said user manipulable object and said actuator, said capstan drive including a capstan drum coupled to said user manipulable object and rotatable about a first axis and a rotatable pulley coupled to and rotatable by said actuator, wherein a flexible member is coupled between said drum and said pulley to transmit rotational force between said drum and said pulley;
• and
• a carriage rotatable with respect to said ground surface about a second axis, wherein said drum is rotatably coupled to said carriage, and wherein said capstan drum and said user manipulable object may be rotated about said second axis while said actuator and said pulley are fixed to said ground surface and do not rotate about said second axis, wherein said flexible member is twisted from said rotation about said second axis;
• whereby said user manipulable object is provided with a first degree of freedom about said first axis and a second degree of freedom about said second axis.

A human-computer interface mechanism comprising:

• a user manipulable object;
• a linkage of members providing two degrees of freedom to said user manipulable object;
• a floating gimbal mechanism coupling said user manipulable object to said linkage of members, said floating gimbal mechanism including:
• a plurality of rotatably coupled gimbal members, said gimbal members providing two rotary degrees of freedom said user manipulable object;
• a sensor provided for each of said gimbal members for measuring a position of said members relative to each other in one of said rotary degrees of freedom, such that each sensor measures motion in a different rotary degree of freedom;
• and
• a capstan mechanism coupled between each of said sensors and one of said gimbal members, each of said capstan mechanisms including a capstan drum rotatable about an axis of one of said rotary degrees of freedom and a pulley coupled to said sensor and coupled to said drum by a flexible member.

A method for interfacing motion of a user manipulable object with a computer system, the method comprising:

• providing a linkage of members movable such that an object engaged with said linkage has first and second degrees of freedom;
• providing a rotatable carriage between said linkage and a ground, said rotatable carriage providing a third degree of freedom to said object;
• actuating a force in each of said three degrees of freedom using first, second, and third actuators, wherein said three actuators are each fixed to a single ground;
• and
• sensing a position of said object in each of said three degrees of freedom;
• and
• providing electrical signals to and from a computer system for controlling said force and relaying said position.

A surgical simulator for simulating medical surgery on a patient, the simulator comprising:

• a human body part model having a point of entry;
• a medical instrument provided on a first side of said human body part model, said medical instrument extending through said point of entry of said model to a second side of said model;
• a floating gimbal device coupled to said medical instrument, said floating gimbal device providing three degrees of freedom to said medical instrument;
• a force feedback interface device coupled to said floating gimbal device, said force feedback interface device providing movement to said medical instrument in three dimensions separate from said three degrees of freedom and providing forces to said medical instrument in said three dimensions, said force feedback device being coupled to a ground on said second side of said human body part model and including three actuators for generating said forces;
• and
• a plurality of sensors coupled to said gimbal mechanism and to said force feedback interface device for sensing a position and orientation of said medical instrument.