Experimental Research On The Dynamic Behavior Of Bipedal Passive Dynamic Walkers

Passive Dynamic Walking (PDW) is a new research area in bipedal humanoidrobots. The Passive Dynamic Walker, which can take full advantage of its dynamiccharacteristics, could walk down slopes autonomously by the gravitational pull. Byapplying this mechanism, new developed underactuated robots will exceed traditionalfull-actuated robots in humanoid walking gaiting, as well as energy efficiency.It is firstly addressed in this dissertation the importance of humanoid robot andPDW research. Worldwide research progress is summarized, with emphasis onexperimental research and physical prototypes. Then requirement analysis is donewith conclusion that a measurement system shall be put up on the existing prototypeof passive dynamic walker. The kinematic and dynamic behavior need to be obtainedthrough the system, followed by multi-body simulation, which serves as comparisonand validation.The geometric model is described and analyzed to specify the interestedparameters to be measured. Measurement schemes are proposed respectively, withsensors defined and selected. The overall architecture of the PC-based automaticmeasurement system employs Virtual Instruments (VI) and multi-functional dataacquisition (DAQ) device. DAQ sampling tasks are designed in LabView software,with each measurement channel fully defined, including mechanic joints, electricconnection and data sockets. The DAQ programs are composed, respectively.Component conditioning and system validation are carried out afterward, withsensitivity of sensors measured and scaled. With whole system fully functional, PDWtest experiments are conducted and the sampled data could clearly reveal the dynamicbehavior of PDW walker.Simulation research is carried out as well. MD/Adams is employed to build upthe simulation environment, which is the virtual mapping of the physical system. TheCAD model that previously set up for prototype fabrication is imported intoMD/Adams as the CAE model. Simulation is done after initial conditions and integral parameters defined. The results match well with experimental data and can be seen asvalid verification of test results, proving that it is also a useful tool in PDW research.New stage of research shall be conducted afterward on different configurationsof PDW walkers, which could introduce more versatile dynamic behavior. A newPDW walker with knee joints is designed. Another virtual prototype is built up forsimulation, whose results reveal that the kneed PDW walker succeeds in walkingdown slopes autonomously. Mechanical structure design is schemed for prototypefabrication. Compared to previous prototype, the design is optimized to improvemechanical performance and stability. The mechanic joints of sensors on the previousprototype are also reserved for the smooth transplanting of existing measurementsystem. Further works could be conducted in-depth as well as extensively.