Effect of changing initial joints position on joint torque required for sit-to-stand motion

• मुख्य लेखक: Kanzal, Sameh Mohsen Omer
• स्वरूप: थीसिस
• भाषा: अंग्रेज़ी; अंग्रेज़ी
• प्रकाशित: 2020
• विषय: T Technology (General); TA Engineering (General). Civil engineering (General)
• ऑनलाइन पहुंच: http://eprints.utem.edu.my/id/eprint/26001/1/Effect%20of%20changing%20initial%20joints%20position%20on%20joint%20torque%20required%20for%20sit-to-stand%20motion.pdf; http://eprints.utem.edu.my/id/eprint/26001/2/Effect%20of%20changing%20initial%20joints%20position%20on%20joint%20torque%20required%20for%20sit-to-stand%20motion.pdf

Sit-to-stand (STS) motion has recently been given an intensive attention by both biomechanical and robotics researchers. STS motion determinants are factors that affect the performance of the STS motion. Determinants differ with their affect based on how they are related to the STS motion, such as chair-related, subject-related and motion-settings-related. Humans who face issues with performing an STS motion find difficulties to perform the motion successfully when they are subjected to wear a prosthetic device. Torque produced by the motors used to help the patients performing an STS motion is one of the parameters that can affect how successful the motion can be performed. Moreover, hip joint’s initial position is one of the parameters that affects the STS motion performed with the aid of the prosthetic devices. It was hypothesized that the relationship between the hip and knee joints initial position (θhip,θknee) and their torque (τhip,τknee) is polynomial. In this project, the objectives were to investigate the effect of changing the hip and knee initial positions on the maximum torque required by each joint to successfully perform the STS motion in both experimental and simulation environment. Additionally, to develop a mathematical relationship that estimates the maximum torque based on either knee or hip initial position then to determine the optimum initial joint position. Experiments were conducted to ensure the validity of the hypothesis. The experiments were designed in a way to imitate the human body measurements and the motion was planned in the same way humans do. The torque produced by each joint was fitted and a 2nd degree polynomial relationship was created to predict the maximum and minimum torque based on the hip’ initial position. The results show that the goodness of the line fitting is close to 1, with a confidence level of 95%, ranging from 0.8672 to 0.9799. Furthermore, the experimental results have shown that the optimal initial-position settings are at θknee=128°, θhip=270° for the lowest τankle=0.3665 N.m and at θknee=78°, θhip=225° for the lowest τknee=0.4223 N.m and at θknee=113°, θhip=270° for the lowest τhip=0.0451 N.m. Thus, the STS motion was analyzed in terms of the effect due to changing the knee and hip initial positions on the maximum torque, then the effect was validated by simulating the changes in V-rep software. As a result of the above analysis conducted in this research, equations were generated from the data collected to estimate the maximum torque values when the initial position of knee and hip joints are known.