Mechanisms for control knobs and other interface devices
Mechanisms for a control knob or other interface device providing additional degrees of freedom for the knob. One embodiment provides a rotatable knob moveable also in lateral plane approximately perpendicular to the axis of rotation. A mechanism providing the lateral motion can include agate member and a plunger member that engages grooves in the gate member. A rotational sensor detects a rotational position and a lateral sensor can detect a lateral position of the knob. Another embodiment provides an actuator that includes a shaft that is coaxial with the axis of rotation and which can be moved linearly along the axis of rotation with respect to actuator housing to accommodate linear motion of the knob. In another embodiment, a gear assembly including two interlocked gears is provided to transmit rotational motion from the knob to the sensor, and the interlocked gears translate with respect to each other when the knob is translate along the rotational axis.
1. A haptic controller device comprising:
a user manipulandum rotatable in a rotary degree of freedom about an axis of rotation extending through said manipulandum, said manipulandum also moveable linearly in a plane perpendicular to said axis of rotation;
a rotational sensor that detects a position of said manipulandum in said rotary degree of freedom;
an actuator coupled to said manipulandum and operative to output a force to said manipulandum in said rotary degree of freedom about said axis, wherein said actuator includes a shaft that is coaxial with said axis of rotation, and wherein said shaft can be moved linearly along said axis of rotation to accommodate said linear motion of said manipulandum; and
a sensor for detecting said linear motion of said manipulandum along said axis of rotation.
2. A haptic controller device as recited in claim 1 , wherein said shaft of said actuator is rigidly coupled to a rotor of said actuator such that said rotor and said shaft can concurrently move linearly along said axis of rotation, and wherein a stator of said actuator is grounded.
3. A haptic controller device as recited in claim 2 , wherein magnets of said stator extend to a length greater than a length of an armature of said rotor, such that said armature is always completely within a magnetic field of said magnets regardless of a position of said shaft along said axis of rotation.
4. A haptic controller device as recited in claim 2 , wherein commutator bars of said actuator are a greater length than necessary if said shaft did not move, such that brushes of said actuator are in continuous contact with said commutator bars regardless of a position of said shaft along said axis of rotation.
5. A haptic controller device as recited in claim 1 , wherein a rotor and a stator of said actuator are grounded with respect to said linear motion of said shaft along said axis of rotation.
6. A haptic controller device as recited in claim 5 , wherein said shaft includes a first feature and wherein said shaft slides within a bore in said rotor having a second feature that engages said first feature and allows said shaft to rotate said rotor.
7. A haptic controller device as recited in claim 1 , wherein said actuator is a DC brush type motor.
8. A haptic controller device as recited in claim 2 , wherein said rotor includes skewed teeth to reduce a cogging effect when said actuator is in operation.
9. A haptic controller device as recited in claim 1 , wherein said user manipulandum is also moveable in a plurality of transverse directions approximately perpendicular to said axis, and further comprising a transverse sensor operative to detect movement of said knob in any of said transverse directions.
10. A haptic controller device as recited in claim 1 , wherein said user manipulandum is a knob.