This video documents the creator's progress on several fronts, focusing on a long-term vision for AI-assisted juggling, significant design changes to the "Ball Butler" robot, and advanced CAD techniques in Onshape. The stream begins with the concept of a "juggling room" equipped with motion capture to develop an AI-powered session analyzer and coach, with a call for community collaboration using provided data. The main focus then shifts to the "Ball Butler" robot, where community feedback prompts major design pivots. The base drive system is redesigned from a complex belt drive with a brushless motor to a simpler, 3D-printed bevel gear system powered by a small brushed DC motor. The creator details the prototyping and testing of this new gear system, including its challenges with mounting, alignment, and pinion attachment. A new concept for a spring-powered mechanical thrower is also explored, leading to the design of a test rig featuring an innovative damping mechanism that uses a second linear carriage with RC car shocks and a multi-material (TPU/PLA) printed bumper. Finally, the creator showcases significant improvements in their Onshape workflow, successfully implementing dynamic part naming via custom feature scripts.
Developing a Juggling Robot: From AI Coaching to Bevel Gears and Multi-Material Printing
0:01:15 - The "Juggling Room" Concept: The creator shares his long-term vision for a dedicated indoor juggling space with high ceilings and motion capture cameras.
0:04:17 - AI-Powered Juggling Analysis: The primary goal of the motion capture setup is to train a program that can automatically track juggling sessions, count catches, identify patterns, and provide performance statistics, a task that is difficult for a juggler to do themselves.
0:08:14 - An AI Juggling Coach: The ultimate goal is to develop an AI coach that can analyze 3D trajectory data to provide specific feedback on technique, such as identifying consistently poor throws.
0:09:52 - A Call for Collaboration: The creator announces he will be making his own 5-ball motion capture data public and invites the community to collaborate on developing the juggling analysis software.
0:17:25 - Redesigning the Base Motor: Based on community feedback, the creator agrees that a brushless DC motor for the robot's base is overkill and decides to switch to a smaller, more efficient geared brushed DC motor.
0:27:11 - Moving Away from Belt Drives: After struggling with the complexity of tensioning and routing a belt drive for the base, the creator decides to explore gear-based solutions to eliminate backlash.
0:37:11 - The Bevel Gear Solution: After a frustrating attempt to create a complex trochoidal drive, the creator realizes that a simple bevel gear system is the ideal solution for a 90-degree power transmission. He uses an Onshape feature script to generate the gears.
0:41:07 - Bevel Gear Prototype Demo: A live demonstration shows the 3D-printed bevel gears, driven by the brushed DC motor, successfully rotating a large bearing. The system is functional but loud.
0:43:08 - Challenges with the Gear System: The new design introduces several problems: the small motor shaft makes it difficult to securely attach the pinion gear, the motor mounting bolts interfere with the gear teeth, and the gears are difficult to align perfectly.
1:13:14 - Exploring a Mechanical Thrower: The creator explores an alternative to a motor-driven throw, discussing a concept where a motor adjusts the tension of a launch spring while the hand is latched, with a separate mechanism (like a solenoid) to trigger the release.
1:30:48 - Innovative Damping System: To test the mechanical thrower, a new rig is designed featuring a clever damping system. It uses a second linear carriage on the same rail, equipped with RC car shock absorbers, to act as a cushioned end stop.
1:33:30 - Multi-Material Printing Experiment: The creator designs and prints a bumper for the damping system using two materials simultaneously: a flexible TPU outer shell and a rigid PLA inner core. The result is a component that is significantly stiffer than one made of pure TPU.
1:51:56 - Dynamic Part Naming in Onshape: A major workflow improvement is achieved thanks to a custom feature script (adapted from community member Alice) that allows part names in Onshape to automatically update based on their configured dimensions.
1:59:54 - The Mate Connector Challenge: The creator highlights a remaining Onshape challenge: finding an efficient way to configure the position of mate connectors for a part with multiple selectable profiles (like aluminum extrusion) without creating an unmanageably large and complex configuration table.