Investigating the relationship between TIP and 3-link models when the links' length are varied

In the field of humanoid and exoskeleton robotics, the ability to perform everyday task as human movement has been crucial point of research. One of the aspects that a lot of researcher put an effort is sit to stand (STS) motion. Study has shown that STS motion can be predicted using Three-link multi segment robot. But the calculation needed to perform the STS motion is complicated and requires high computational resources. One model is found that has much simpler task for planning and analyzing humanoid or exoskeleton robot which is Telescopic Inverted Pendulum (TIP). TIP is using one single link to represent whole body. However it is not clear whether TIP can represent 3L multi segment robot yet. Thus, this paper objective is trying to find the relationship between TIP and 3L model when the length of the limbs is varied. To do so, MATLAB is used to simulate the STS motion for both 3L and TIP model. The torque values at each joint are observed to obtain the relationship between length and the torque. The results show that both TIP and 3L model give a similar result where the limb's length and joint torque have linear relationship.