Two Degree-Of-Freedom Vibratory Transport in a Grasp
Connor Yako, Shenli Yuan, Kenneth Salisbury
AI summary
Problem
Existing vibration-based manipulation relies on unpredictable impact motors or requires precise knowledge of friction and mass, limiting practical in-hand control. How can asymmetric vibrations be systematically controlled to drive grasped parts in multiple degrees of freedom?
Approach
The authors derive analytical trends for how sticking and slipping accelerations affect part velocity, then validate them using a position-controlled vibrating surface driven by voice-coil actuators.
Key results
- Demonstrated gravity-defying transport and rotation without impact motors
- Validated that higher slipping and sticking accelerations increase average part velocity
- Developed a 2-DoF vibrating finger enabling independent translation and rotation
- Confirmed translation waveform trends persist for in-plane part rotation
Why it matters
Provides a mechanically simpler, highly controllable alternative to roller-based or impact-driven active surfaces for complex in-hand robotic manipulation.
Abstract
In this paper, we use asymmetric vibrations to demonstrate two degree-of-freedom (DoF) in-hand manipula- tion of grasped parts. The asymmetric vibrations are achieved through closed-loop position control of a moving surface, which applies a periodic stick-slip waveform to the part to be manipulated. We show analytically how two vibratory waveform parameters, the sticking acceleration and the slipping acceleration, affect average part velocity when moving against gravity. The theoretical trends are then validated using an experimental setup where the squeeze force is controlled and part motion is recorded by a high-resolution encoder. We also develop a 2-DoF vibratory surface capable of translation in one direction and rotation about the surface normal. Using two of these 2-DoF surfaces in a parallel jaw gripper configuration, we bidirectionally translate and rotate a variety of grasped parts, as well as demonstrate that the same waveform trends for translation also persist for in-plane rotation.