Designing humanoid robots with human-like spines and skeletal anatomy presents several technical challenges and considerations:
Complexity and Cost: Bones of the human spine and skeletal system are diverse and multi-functional with a great deal of versatility, and strength in bearing loads. This level of complexity would be very difficult to recreate in robots, because of the additional and complex materials needed in the construction, as well as the improved control systems necessary for its operation, which would sky-rocket the manufacturing costs for these robots.
Functionality: Human spines are encompassed to facilitate standing, walking, bending and twisting related exercises. This versatility is fine for a human who may need to move from desk to factory floor but robots usually have a more defined role. It may not be necessary for many applications to design a robotic spine with the same sort of flexibility but such flexing may introduce complexity, instability or inefficiency into spinal structures.
Material Limitations: Current materials and technologies may not be able to offer the structural strength and movement functionality as bones and joints do. However, human bones are also hard, lightweight and possess the degree of bone regeneration as a good ability. The problem lies in searching for materials that can have these properties or in the search for creating materials with such characteristics.
Control and Coordination: The human nervous system is well developed and adapted to our sophisticated musculoskeletal system, and the control of it is bilaterally symmetrical. Bringing the same level of control in robots is only possible if a robot is capable of having the same level of software and sensors, the development of which is still in its infancy.
Design Philosophy: Most robots are not built to copy human biomechanics to the letter big picture goals that robots are built to accomplish are seen over a much more narrow framework than mimicry of the human body. For example, rather than having a torso and human-like spine for locomotion, which may not be efficient for some movements or terrains, the robot might have wheels or very basic joint mechanisms.
Robustness and Maintenance: It is worth remembering that spines of humans are vulnerable and degrade with time and external impacts. Sturdier constructs, which are not as mechanistically complicated, can be used in robots so that they will work longer and it will cost less to fix up and keep them running.
Although the concept of applying human-like spine structures to humanoid robots is quite engaging and can be viable for specific purposes, technology trends and the realism of robotics implementation can point out completely different direction towards more beneficial solutions. It is possible that in the future, robots will look more like anatomically correct replicas of the human body; however, the principle of applied technology tends to bow down to pragmatic trends.
