What Strategy Central Nervous System Uses to Perform a Movement Balanced? Biomechatronical Simulation of Human Lifting

Abstract

Abstract. How does the central nervous system control the body posture during various tasks despite a redundancy? It's a well-known question existed in such fields of study as biomechanics and bioengineering. Some techniques based on muscle and torques synergies are presented to study the function which Central Nervous System uses to addresses the kinetic redundancy in musculoskeletal system. The human body with its whole numerous joints considered as a hyper redundant structure which caused to be seemed that it is impossible for CNS to control and signal such system. To solve the kinematic redundancy in previous studies it is hypothesize that CNS functions as an optimizer, such of that are the task-based algorithms which search to find optimal solution for each specific task. In this research a new objective function based on ankle torques during movement is implemented to guarantee the stability of motion. A 2D 5DOF biomechatronical model of human body is subjected to lifting task simulation. The simulation process implements inverse dynamics as major constraint to consider the dynamics of motion for predicted postures. In the previous optimization-based techniques which are used to simulate the human movements, the motion stability was guaranteed by a nonlinear inequality constraint which restricts the total moment arm of the links to an upper and lower boundary. In this method, there is no need to use this constraint. The results show that the simulated postures are normal and the predicted motion is performed completely balanced.

Robot body self-modeling algorithm: a collision-free motion planning approach for humanoids

“…A set of similar optimization problem solving process have been employed in previous studies (Xiang et al 2009 , 2010a , b ; Leylavi Shoushtari 2013 ; Chang et al 2001 ) for motion prediction and motion planning purposes. In this study, the optimization problem is designed for 10 evenly distributed time segments.…”

“…In this study an optimal motion planning approach (Leylavi Shoushtari 2013 ) is implemented to simulate manual lifting task. The approach uses inverse dynamics equation as an equality constraint to consider the dynamics of subjected motion in simulation process.…”

“…From engineering point of view the redundancy both in kinematic and kinetic levels is considered as a problem in terms of system analysis while at the same time, it is a privilege in sense of design (to create a high maneuverable system). Evaluation and studying the human CNS’s strategy in performing dynamic tasks such as lifting (Ayoub 1998 ; Hsiang and Ayoub 1994 ; Xiang et al 2010a ; Sitoh et al 1993 ; Leylavi Shoushtari 2013 ), walking (Anderson and Pandy 2001a , b ; Xiang et al 2009 ), jumping (Babič et al 2006 ), somersault (Blajer et al 2007 ) and standing up (Mistry et al 2010 ; Lord et al 2002 ; Janssen et al 2002 ) is considered as a source of inspiration to control, motion planning (Abedi and Leylavi Shoushtari 2012 ) and motion learning (Oztop et al 2008 ) of humanoids. The main idea is that human CNS considers several dynamic and static criteria to perform those tasks.…”

Bio-inspired kinematical control of redundant robotic manipulators

“…In particular, human motion principles, e.g. metabolic energy consumption Cruse et al (1990) and postural stability Leylavi Shoushtari (2013), are designed as cost functions which are subjected to be minimized by an optimal motion planning algorithm. Complexity and difficulty-to-generalization represent their main deficiencies.…”