For our grabber mechanism, we are designing a claw-like design that uses both a rigid frame and flexible TheraBand Thera-Band to gently and accurately pick up objects of various sizes and weights.
The rigid frame portion is comprised of two flat, four sided, slender frames, tensioned together by Elastics at the start and bottom, and attached to an axle at the top. The frames are then pulled apart with two servos when going to grab an object. When completely closed, the rigid frame supports the object from the bottom and ensures the object is secure. The TheraBandThera-Band, which surrounds the sides of the is attached to each frame, creates a wall in front of the frameflexible wall to contour around objects being picked up. When the frame closes on the object, the TheraBand Thera-Band bends around the object, creating a tight and secure grab on whatever object is being picked up.
We chose to go with this design because it is lightweight and allows flexibility in what can be picked up. Because we don’t know the The specific dimensions and weight of the object we that will be required to pick up at competition are unknown, this design allows for flexibility to gently and accurately grab any object less than 20cm^3 and 2 kg.
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. The following image shows the grabber design when mounted to the bottom of the drone frame.
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The following image shows the grabber opening to pick up the blue cube.
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Features and Capability
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Thera-Band
The use of TheraBand Thera-Band allows for a wide range of objects of various shapes and sizes to be secured. By attaching theraband Thera-Band across two rigid frames opposite one another, the object can be centred centered between these two planes, which are then actuated shut. The elastic force of the TheraBand Thera-Band will increase as it encloses stretches to fit around the object. With this, the elastic force creates a strong enough normal force with the object in the horizontal direction, which will correspond to a higher friction force between the theraband Thera-Band and the object thereby opposing the gravitational force of the object.
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