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:
a first Evans mechanism, said first Evans mechanism being adapted and configured to describe a first linear trajectory portion and a second arcuate trajectory portion;
a second Evans mechanism, said second Evans mechanism being adapted and configured to describe a third linear trajectory portion and a fourth arcuate trajectory portion; and
a ground member, said ground member including first and second sarrus hinges, said ground member being mutually coupled to said first Evans mechanism and to said second Evans mechanism such that said first and second Evans mechanisms are adapted and configured to move substantially in opposition to one another through said first and third linear trajectory portions respectively to produce a desirable haptic signal of said haptic actuator.
2. A haptic actuator as defined in claim 1 wherein said second and fourth arcuate trajectories terminate in a common direction.
3. A haptic actuator as defined in claim 1 wherein said first and second sarrus hinges each comprise a plurality of substantially rigid layers of material.
4. A haptic actuator as defined in claim 1 wherein said first Evans mechanism includes a first output member and said second Evans mechanism includes a second output member.
5. A haptic actuator as defined in claim 4 further comprising a first inertial mass coupled to said first output member and a second inertial mass coupled to said second output member.
6. A haptic actuator as defined in claim 1 further comprising a first inertial mass coupled to said first Evans mechanism and a second inertial mass coupled to said second Evans mechanism.
7. A haptic actuator as defined in claim 1 , further comprising a motor, said motor being mutually coupled between said ground member, said first Evans mechanism and said second Evans mechanism, said motor being adapted to motivate said first and second Evans mechanisms through said first, second third and fourth trajectory portions respectively.
8. A haptic actuator as defined in claim 7 wherein said motor comprises a voice coil.
9. A haptic actuator as defined in claim 1 wherein said desirable haptic signal comprises a tap signal.