Changes between Version 6 and Version 7 of Hand/280/MassByJoint


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Timestamp:
Jul 31, 2012, 6:03:05 AM (7 years ago)
Author:
dc
Comment:

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  • Hand/280/MassByJoint

    v6 v7  
    11= Inertial Tensors and Mass Properties for the BarrettHand BH8-280 =
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    3 The inertial properties calculated here represent the masses and inertias of each link of the BarrettHand BH8-280. All calculations were made using SolidWorks 2012 SP 3.0 and CAD models that include all mechanical components of the hand (including fasteners) and all electrical components except wiring. To verify that masses were correct, The mass of an actual finger was measured at
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     3The inertial properties calculated here represent the masses and inertias of each link of the BarrettHand BH8-280. All calculations were made using SolidWorks 2012 SP 3.0 and CAD models that include all mechanical components of the hand (including fasteners) and all electrical components except wiring. To verify that the SolidWorks model was correct, assemblies and parts of an actual hand were massed for comparison.
     4
     5The mass of an actual finger was measured at 179 g, which matches the mass of the CAD model. The hand base (including pucks and finger motors) measured 664 g while SolidWorks calculated the mass of the CAD model to be only 643 g. This discrepancy could come from a number of sources:
     6
     7 1. Lack of wiring in CAD
     8 1. Lack of grease in CAD
     9 1. Inadequately modeled PCB and components
     10
     11Further investigation narrowed the source of error to subassemblies with dozens of strands of wire, all of which were omitted in the CAD model. To replicate the mass of these wires, slugs of the discrepant mass were created to fill the cavities in which wires could run. The base CAD model used now measured 664 g.
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     13In the following images, all parts are left transparent to display all parts of the mass calculations. Yellow denotes frame parts, red denotes electrical pieces, and blue is for motors and drivetrain components.
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     15The following frames were established on the hand. These inertial frames follow the same convention as on the BarrettHand BH8-262.
     16[[Image(AllFrames_crop.jpg)]]
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