Development of a human hand model for estimating joint torque using MATLAB tools

Determining the joint torques of the hand is a useful design parameter for humanoid mechanism, rehabilitation robots and orthotic and prosthetic devices. In previous studies, different methods have been suggested for estimating joint torques of the hand such as mathematical models and simulation models. This paper presents a 16 DOF hand kinematic model and its simulation. Kinematic structure of an average human hand was created by SimMechanics and Simulink on MATLAB. The model was simulated by inverse dynamics method using the video record of a healthy subject (male, 29 years, 71 kg and 174 cm) and the joint torques of the index finger and wrist were calculated. The maximum torque at index finger with 0.015 Nm occurs at the MCP joint during the cylindrical grip. The maximum wrist torque was calculated as 0.225 Nm during movement of flexion/extension. Flexion/extension and abduction/adduction movements of the fingers and the wrist can be analyzed with this model changing joint rotation axis easily. This MATLAB model can be used in order to calculate the joint torques at different movements of the hand without complex equations and external devices.