Pressure Sensitive End Effector
A pressure-sensitive grabbing unit developed to be mounted to the bottom of a drone for autonomous flight and operation.
Skills:
Linkage Design, Embedded Systems & Rapid Prototyping
Design Criteria and Test Results
Minimum required design specifications:
- 8x8x8cm carrying size
- 1kg load capacity
- Compact size, servo-driven
Final design capabilities:
- 12cm x 12cm
- Soft Jaws
- 5kg load capacity
- Servo Driven
The original link proportions and sizing were based on a motion path generated in the program linkage. These measurements were then used to create 3D part models, which were then used to create the entire assembly. All moving components and housings are located via through bolts, which run through both housings and are captured with locknuts. While the prototype just used dry lube between the components and the bolts, the final version was slated to use bushings with parts sidewhiched between some UHMW shim stock to reduce friction and wear between parts.
The grabbing arm mechanism was driven via two servo motors that had gears attached to be able to utilize the full 180 degrees of the motor. In addition, it increases the amount of torque exerted through the system, allowing for greater carrying capacity with a final capacity of 5kg. Additionally, this was useful for object detection, which was measured via current load as the lower torque requirement steadied the lower input current
Testing showed that the mechanism was able to pick up a regular-shaped object weighing upwards of 5 kg, with irregular-shaped objects of roughly 3.5 kg being able to be lifted. The main limiting factor with those is the amount of clamping area, which is helped by the soft jaws, but is not enough to perform nearly as well as regular-shaped objects.