Parallel Axis Tripteron
Parallel Axis Tripteron
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Theory:
Theory:
A tripteron is a general term for a 3-axis movement system that uses double-arm linkages to resolve a final point in (x,y,z) using linear positions along rails as input variables. A parallel axis tripteron aligns all 3 linear rails in parallel and translate the movement into cartesian space using 4 linked arms.
Design Challenge:
Design Challenge:
A need exists for a machine able to pick up and move small objects from one location to another while having a high accuracy motion system, and a large and flexible range of reachable locations.
Design Objectives:
Design Objectives:
Accuracy/Precision of object placement
Range of motion to pick up objects from multiple storage areas
Tested and Assembled Body
Tested and Assembled Body
I was personally responsible for linkage manufacturing and assembly, with the arms being made from a mix of waterjet 3/8" and 3/16" aluminum sheet, held together using m5 hardware.
Assembled Support Structure
Assembled Support Structure
Designed support structure to balance SOG in accordance with tipteron movement.
Designed Linkage and Bearing Stack
Designed Linkage and Bearing Stack
Iterated on linkage design and bearing stack, optimizing for rigidity and range of motion. Furthermore, developed guidelines for ROM vs Rigidity tradeoffs.
Linkage Design
Linkage Design
Each arm is designed with 4 primary links, with a thrust-needle stack providing smooth rotation and bending support. The joints themselves are 25mm M8 female ended pins with bolds on either side providing clamping force to the bearing stack. Aluminum thicknesses were chosen to withstand +10kg before deflection defection.
BOM and Book-keeping:
BOM and Book-keeping:
Handled BOM management and book-keeping for the entire project, ensuring the final raw BOM was under $300 CAD, and that project deadlines for machined parts/assembly was completed on time.
Additional Project Components:
Additional Project Components:
PCB Design
PCB Design
Teensy 4.1 breakout board with 4 stepper drivers used to operate 3 steppers mounted behind linear rails, and a PWM electromagnet output port designed to output 10A steady and 20A peak
Range Optimization
Range Optimization
By iterating the arms lengths and angles, the ROM in x-z plane at any y-length can be optimized for maximum range. Using these defined angles, inverse kinematics are used to determine the forward transform functions which relates cartesian head position to linear rail distance of each carriage.
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