3D Twist and Tilt Bipedal Model and Control Realization for Sit to Stand

The field of biomechanics for human voluntary motions in three dimensions encompasses a wide array of applications. The process of transitioning from a seated position to a standing position, referred to as sit-to-stand, is a basic motion that is frequently executed during various everyday tasks. The current investigation centers on enhancing 3D bipedal locomotion through the creation of a novel system utilizing a Twist and Tilt scheme to perform sit-to-stand (STS) movements. This mechanism, in contrast with previous models, does not consider any foot fixed for the whole profile. This type enables one foot to perform a twisting movement and the other foot to perform a tilting movement. The tilt foot schematic is built with two distinct schemes: one involving sliding tilt, the other with rotating tilt. This scheme is designed to study STS issues faced by neurologically deficient human beings while carrying out different joint positions. The twist and tilt models are designed using computer-aided design (CAD) software. They consist of an 8-part bipedal structure, which includes two feet, two calves / shanks, two thighs, one pelvis, and one HAT section. Both of these twist and tilt models are first produced in SOLIDWORKS Corp software. Subsequently, to facilitate control implementation, these models undergo linearization using SIMULINK / SIMSCAPE and MATLAB. By employing the analysis of Controllability and Observability, it is revealed that the design, which incorporates one foot linear tilt, consists of twelve states. Furthermore, it is determined that one foot linear model has full rank controllability and observability and is suitable to design controller.