Building small robot legs with pre-fabricated components is difficult...

1. Shaft coupling Shaft Motor Leg links Building small robot legs with pre-fabricated components is difficult... Boadicea leg Electric motor/link Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

2. IV. Fabrication and integration experiments 2:00-2:30pm (*Cutkosky, Kenny, Howe) • Overview of SDM fabrication process, capabilities, challenges • Autonomous robots: experiments with UCB, SRI, (others?) • Cooperative robots: experiments with Harvard, Johns Hopkins, UCB

3. Concept design for a biomimetic “Insect-Leg” A prototype design of the same leg employing three-dimensional plastic “exoskeleton” surrounding with embedded actuators, sensor and cooling system. Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

4. Mechanics and muscle activation patterns (R. Full) Three-dimensional musculo-skeletal model of the leg of B. discoidalis constructed by Full’s lab. Simulations such as these help characterize the role of individual muscles in locomotion. Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

5. Shape Deposition Manufacturing(SU/CMU) Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

6. SDM allows finished parts to be inserted at any point in the cycle Green link and red bearings are added as finished components Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

7. SDM capabilities • Slides and web pages of parts that would be difficult or impossible to create using conventional manufacturing methods • Topology that would be almost impossible with conventional machining tilted frame (CMU/Stanford) • Integrated assembly of polymers with embedded electronics and interconnects (CMU Frog Man) • other example parts from RPL at Stanford Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

8. Frogman (CMU) • Example of polymer component with embedded electronics using shape deposition manufacturing Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

9. MicroStructures and Sensors Lab (MSSL) Kenny Research on Fundamental Properties and Applications of MEMS-based MicroMechanical Devices. • Micromechanical Sensors. • Micromechanical Elements for Scientific and Technological Collaboration Partners. • Devices and Instruments for Studies of Fundamental Properties of Micromechanical Structures. Collaborators : IBM, JPL, NRL, SNL, SAIC, Medtronic, Raychem, Lucas, Seagate, Perkin-Elmer... Students from :ME, EE, Appl Phys, A/A Piezoresistive Lateral Accelerometer 2-Axis AFM Cantilevers for Surface Friction Experiments and Thermomechanical Data Storage Flow Visualization in Microchannels Ultrathin Cantilevers for attoNewton Force Detection

10. Embedded SMA actuators • Intial experiments with epoxy and urethane polymers and various sacrificial supportmaterials have underscored the need tobuild in disposable fixtures for proper alignment. Shape Memory Alloy wire with water cooling channels Epoxy acrylic Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

11. Embedded sensor example: pressure sensor unit for pneumatic actuators PC board CAD file for commercial MEMS pressure transducer & instrumentation Screen shot from SDM CAD environment: several steps in the “building block” design/fabrication sequence for the embedded pressure sensor package Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

12. Embedded sensor example (continued) A batch of four parts during the final machining step. Part material is urethane (yellow). Sacrificial support material is wax (red), filling cavities and encasing the circuit leads to protect them. Completed pressure sensor unit ready for connection to a pneumatic actuator. Fabrication instructions archived at http://cdr.stanford.edu/dml/biomimetics/documents.html Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

13. Approaches to design with layered shape manufacturing Usually people think of taking a finished CAD model and submitting it for decomposition and manufacture Example: the slider-crank mechanism, an “integrated assembly” built by SDM Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

14. SDM process planning: geometric decomposition for tool access build direction Cross section of part material (gray) in support material Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

15. Decomposition into ‘compacts” and layers • Several levels of decomposition are required Complete Part Compacts Layers Tool Path Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

16. Testing for compactness Z There exists no point, p, on S which is an inflection point with an undercut surface above an upward-facing surface. Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

17. Layers produced by automatic decomposer for slider crank mechanism Gray = steel, brown = copper support material Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

18. Layered shape deposition - potential manufacturing problems • finite thickness of support material • poor finish on un-machined surfaces • warping and internal stresses Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

19. Slider crank can be built entirely from two kinds of primitives Yellow = part material, blue = support material Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

20. Merge algorithm for compacts (Binnard) f (a,b ) Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

21. Building Designs from Primitives • Here is the result of building slider-crank from primitives • allows manufacturability analysis at design time Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

22. What gets sent to the Manufacturing Service What the Designer works with Primitives + Merging Rules SFF Object made up of Part and Support Compacts The Final Geometry Building a robot joint from a library of shapes Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

23. Design for a prototype pneumatic knee joint built from primitives (M. Binnard) Magnetic Gear Tooth Sensor Pneumatic Actuator Link 1 Link 2 Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA

24. a) (top view) b) (side view) d d d(a1,a2) d(a1,a2) l 2l Dd Minimum gap/rib thickness Generalized 3D gap/rib e) (side view) 2l l d(m1,m2,m3) d(m1,m2,m3,a1,a2) Wc/l >= 2 m1 m2 m3 m1 m2 m3 Minimum feature thickness Comparison with VLSI approach SFF-MEMS VLSI Boxes, Circles, Polygons and Wires Decomposed Features SFF-MEMS Design Rules Mead-Conway Design Rules Sept 9-10, 1998 MURI Kick-off meetings, Berkeley/Stanford, CA