The utilization of parallelogram structure in a small-sized humanoid robot consists of two parallel platforms that are linked serially in each leg. The thigh and shank of each leg consists of two servomotors as actuator and linked in parallel platform. By using parallel mechanism in leg structure, foot sole surface is always parallel to the walking surface at any point. Even it looks unnatural to human-like walking motion, the expected result is the robot can maintain it posture while walking and at the point foot sole touch the walking surface, unnecessary vibrates can be modulated at the certain level to remain its balance. The effectiveness and the performance of the proposed parallel platforms are experimented by using zero moment point (ZMP) method by taking various scenario data from pressure sensors attached at the footsole. Planned walking gait is introduced to be identical in terms of foot steps length and width of each leg swing. As the results, in terms of load in each actuator, required torque at servomotors can be reduced because two servomotors are used simultaneously in one parallel system. Stable walking gait can be predicted as the quantity of error falls within the error ranges from the published walking gait patterns.
This study focuses on the effect of boronizing medium on the boride layer thickness of pack boronized 304 stainless steel after surface modification. Pack boronizing treatment was conducted in temperature of 900oC for a duration of eight hours. The treatment was performed using two different boronizing mediums which are powder and paste inside a tight box in an induction furnace. The characteristics of the samples were then observed using optical microscopy and XRD analyser. The thickness of boride layer was then measured using MPS digital image analysis software. The results showed that boronizing medium significantly affected the thickness of boride layer as paste boronized samples exhibited thicker boride layer thickness. The enhancement was mainly due to the size of boron particle in the paste medium which was smaller than powder medium that enabled better diffusion. It is expected that the enhancement of the boride layer thickness would result in further improvement of the mechanical and wear properties of this material.