Asymmetric and general vibration waveforms from multiple synchronized vibration actuators

A vibration device, comprising:

• a mounting platform;
• a plurality of eccentric rotating mass actuators, each of the plurality of eccentric rotating mass actuators attached to the mounting platform;
• and
• a controller coupled to the plurality of eccentric rotating mass actuators to independently control a frequency and a phase of each eccentric rotating mass actuator.

A vibration device, comprising:

• a mounting platform;
• a pair of linear resonant actuators arranged in parallel and attached to the mounting platform, each linear resonant actuator including a moveable mass;
• and
• a controller coupled to the pair of linear resonant actuators, the controller being configured to control a first one of the linear resonant actuators to impart a first sinusoidal vibration force of a first frequency f1 onto the mounting platform, and to control a second one of the linear resonant actuators to impart a second sinusoidal vibration force of a second vibration frequency f2 onto the mounting platform, the second frequency f2 being an integer multiple of the first frequency f1;
• wherein the controller is further configured to control amplitudes and phases of the first and second sinusoidal vibration forces to generate a combined vibration waveform that is asymmetric.