Next Planet Confidential DARPA – MAX program Phase Two Progress Report May 19, 2000

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Summary Success in this phase is achievable based on extrapolations from standard technologies and practices in the prosthetics industry. Our materials technology is rapidly improving and our understanding of the biomechanics involved is rapidly evolving. We are well positioned to leverage these factors into a safe, efficient, workable human powered demonstration of a mono stored energy tendon (" SET").

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Materials The team is having great successes with improving the performance of the PolyDCPD composites with a 200% to 300% improvement in performance over what we had measured just a few weeks ago. The resulting improvements lead us to believe that we can exceed the performance required and add the benefits of toughness, cost, longevity, over the base-line epoxy laminates by using PolyDCPD resins.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Biomechanics The team has also created a new design for the BIOMECHANICAL TEST RIG. This rig will allow us to rapidly determine the required efficient and intuitive biomechanical characteristics of the system, and the spring parameters required to produce them.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Investigated Materials E-glass / PolyDCPD composite (ongoing) 200% to 300% improvement in properties in the last month. Core materials See following examples of compression tests and physical properties. Base-line resin systems in final testing phases See following examples of physical properties and tensile test specimen photos.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Syntactic Foam Core K1 ® Density – 31 pounds per cubic foot HDT – 130° C Compressive Strength – 3,100 psi Compressive Modulus – 234,000 psi

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Syntactic Foam Core K25 ® Density – 34 pounds per cubic foot HDT – 135° C Compressive Strength – 5,300 psi Compressive Modulus – 303,000 psi

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Syntactic Foam Core S38 ® Density – 39 pounds per cubic foot HDT – 140° C Compressive Strength – 11,000 psi Compressive Modulus – 410,000 psi

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Tensile Test Specimens

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Tensile Test Specimens-Detailed View

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Standard PolyDCPD Tensile Strength – 9000 psi Elongation (at yield) – 5.0% Ultimate Elongation > 10% Tensile Modulus – 355,000 psi Flexural Strength – 14,200 psi Flexural Modulus – 310,000 psi HDT 264 psi) – 140° C Notched Izod (ftlbs/in 2 ) Falling Weight Impact > 20 (ftlbs w/ ½” d.tup) (1/8” sheet)

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Toughened PolyDCPD Tensile Strength – 7,700 psi Elongation (at yield) – 6.0% Ultimate Elongation > 30% Tensile Modulus – No Data Flexural Strength – No Data Flexural Modulus – 306,000 psi HDT 264 psi) – 140° C Notched Izod (ftlbs/in 2 ) (Recent formula 12.0) Falling Weight Impact > 30 (ftlbs w/ ½” d.tup) (1/8” sheet)

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Materials To Be Investigated Carbon fiber composites Carbon fiber sizings – dependant upon results of glass fiber tests. Fiber testing becomes major focus for materials lab in 30 to 60 days. (This is after glass fiber tests.) Fiber orientations Technology transfer from prosthetics practice. Testing begins in 30 days. Layered variable modulus composites Tests begin late into Fiber Orientation Testing.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Prosthetics-Based Research Literature search of related composites lead to the investigation of technologies used in prosthetics. Technical meetings and design sessions with engineering professionals from the prosthetics industry. Preliminary design of a base-line basic default configuration of a tendon capable of the energy storage and delivery required, based upon prosthetic technology.* *NOTE: This non-optimized design will be used primarily as a comparison for our other designs. Our goal is to build a more efficient and intuitive design.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Comparative Base-Line Design

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Bio-Mechanical Test Rig Analysis of biomechanical needs of the operator indicated the need for human-factors experiments to determine the proper method to input energy to the system and proper accelerations (spring rates) and intuitive factors for the system. Thus, the team has created a design concept for an apparatus to be used in human factors and spring rate experiments: Experiments will determine the spring rates and "curves" to be used in final tendon. Experiments will determine the intuitive timing of inputs. Energy input mechanics will be designed according to the derived data.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Test Rig Figure 1

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Test Rig Figure 2

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Force diagrams

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Energy input designs

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Additional Tendon Design factors Overload Condition Safety will be built in. Overloads will not break tendon. Overload condition only makes soldier take some of the load by bending their body and legs further. (Just as happens when jumping a moderate distance.) This bending can be made tolerable and controlable, but will be an intuitive deterrent to getting into overload situations. “Dry Fire” – Tendon slipping, will not cause tendon failure.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Overload Protection

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Additional Tendon Design factors Different Tendons for Different Missions: Base-line Tendon for 175 pound payload with adequate overload protection. Extended capability has larger overload margin for control of heavy loads and unexpected higher energy jumps and landings. Special Ops Tendon configured for very high overload margins.

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential Tendon Configurations

DARPA – MAX ProgramPhase 2 Progress Report May 19, 2000Next Planet Confidential DARPA – MAX program Next Steps. Continue materials testing. Continue investigating prosthetics technology Continue literature searches Build biomechanics test rig. Build biomechanics database. Next report June 30 th.