COMPLEX MASS TRAJECTORIES FOR IMPROVED HAPTIC EFFECT
A haptic actuator includes mechanical links defining a first J-trajectory and mechanical links defining a second J-trajectory as well as a motor coupled to the mechanical links so as to synchronously accelerate a first mass over the first J-trajectory and a second mass over the second J-trajectory. During a first time interval, reactive forces of the first mass accelerating substantially balance reactive forces of the second mass accelerating and during a second time interval reactive forces of the first mass accelerating do not substantially balance reactive forces of the second mass accelerating. This un-balanced condition results in a tap signal being produced.
1 . A haptic actuator comprising:
an electric motor;
a storage apparatus, said storage apparatus including an inertial mass, said storage apparatus being operatively coupled to said motor and adapted to receive an accelerative force from said motor, said storage apparatus consequently being adapted to accumulate energy in a spatial motion of said inertial mass; and
a secondary actuator, said secondary actuator being operatively coupled to said storage apparatus, said secondary actuator being adapted to effect a transition of said storage apparatus from a first concentrically balanced mechanical state to a second concentrically balanced mechanical state, wherein said transition is adapted to cause said storage apparatus to release a portion of said accumulated energy as a crisp linear axial impulse.
2 . A haptic actuator as defined in claim 1 wherein said accelerative force is an angular accelerative force.
3 . A haptic actuator as defined in claim 1 wherein said secondary actuator comprises first and second magnets, said first and second magnets being oriented for attraction to one another, wherein during said first concentrically balanced mechanical state said first and second magnets are disposed relatively proximate to one another, wherein during said second concentrically balanced mechanical state, said first and second magnets are disposed relatively distal to one another, and wherein said transition includes a displacement of said first magnet away from said second magnet.
4 . A haptic actuator as defined in claim 3 wherein said first magnet includes a permanent magnet.
5 . A haptic actuator as defined in claim 3 wherein said second magnet includes an electromagnet.
6 . A haptic actuator as defined in claim 5 wherein said electromagnet includes a stator magnet of said electric motor.
7 . A haptic actuator as defined in claim 3 further comprising a mechanical linkage, said mechanical linkage being disposed between said storage apparatus and said secondary actuator, said mechanical linkage being coupled to said first magnet so as to urge said first magnet away from said second magnet as said storage apparatus accumulates said energy.
8 . A haptic actuator as defined in claim 1 further comprising:
a motor shaft, said storage apparatus being operatively coupled to said motor through said motor shaft, wherein said inertial mass includes first and second inertial mass portions, said first and second inertial mass portions being disposed substantially symmetrically about a longitudinal axis of said motor shaft.
9 . A haptic actuator as defined in claim 8 wherein said transition of said storage apparatus from said first mechanical state to said second mechanical state is adapted to permit said first and second mass portions to move respectively away from said motor shaft.
10 . A haptic actuator as defined in claim 9 wherein said storage apparatus includes a pivotal linkage, said first mass portion being operatively coupled to said motor shaft through said pivotal linkage.
11 . A haptic actuator as defined in claim 10 wherein said pivotal linkage includes a four bar parallelogram linkage.
12 . A haptic actuator as defined in claim 10 wherein said pivotal linkage includes an Evans linkage.
13 . A haptic actuator as defined in claim 1 wherein said inertial mass includes a first mass portion and a second mass portion, said first and second mass portions having equal mass.
14 . A method of operating a haptic actuator comprising:
providing an electric motor;
providing a storage portion, said storage portion including an inertial mass and an axis of rotation, said storage portion being operatively coupled to said electric motor;
providing a secondary actuator, said secondary actuator being operatively coupled to said storage portion,
operating said electric motor to provide an accelerative force from said electric motor to said storage portion;
accumulating energy from said accelerative force in a spatial motion of said inertial mass; and
operating said secondary actuator to effect a transition from a first mechanical state of said storage portion to a second mechanical state of said storage portion, whereby said storage portion is adapted to release a portion of said accumulated energy as an axial linear impulse.
15 . A method of operating a haptic actuator as defined in claim 14 wherein:
providing said secondary actuator further includes providing first and second magnets, and wherein said transition from said first mechanical state to said second mechanical state includes overcoming a mutual magnetic attraction between said first and second magnets, and moving said first magnet away from said second magnet.
16 . A method of operating a haptic actuator as defined in claim 14 wherein said operating said electric motor to provide an accelerative force from said electric motor to said storage portion comprises:
rotating a shaft of said electric motor, and thereby rotating said inertial mass about a longitudinal axis of said shaft.
17 . A method of operating a haptic actuator as defined in claim 14 wherein said release of said portion of said accumulated energy as an axial linear impulse comprises:
allowing first and second portions of said inertial mass to move in a centrifugal motion away from one another; and
coupling said centrifugal motion through a pivotal link to produce said axial linear impulse.