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In this video the latest version of the CAD for my new #3dprinted #robot #arm and #hand design is shown. This is version 20. By this stage I'm really hoping to only be making improvements in the fine details of the CAD model - of which there are an endless amount. Like a poem, a great design is never finished, it can only be abandoned. Bit melodramatic, but they were poets :-) This version includes the details discovered during the assembly of the latest physical prototype which is always an enlighening process. Some things are easier to hand make on the real robot before being modelled in the CAD e.g. the running of the tendons and electrical wires and other details are just not obvious until it all comes together. Here a weak spot only became obvious due to an unforeseen change in the 3d printing process that had been so reliable all summer long (clue was there all along). The remedy required changing the dimensions of the main split line on the forearm case which inevitably will have knock on effects, despite taking measures to build an inherently stable model. The alternative is to add endless patch repairs at the end of the design path but this brings its own problems and is not tenable long term. The real shells have been printed in PETG and now CF nylon for higher performance but here it is easy to make them completely transparent allowing the inner mechanisms to be seen. The arm can be completely self-contained with room for six li-ion 18650 cells in the upper arm and two more in the forearm. Onboard computing is from an mbed in the upper arm and an arudino in the forearm with wireless communications using ZigBee serial and SBus. The forearm and hand can operate as a stand-alone unit allowing unlimited axial rotation for rotational tasks like scrubbing. Ref: SOLIDWORKS 2018 SP5 0 Complete Arm 20 SLDASM 2022 10 14 09 23 14
