Towards the Development of Pneumatically Actuated Soft Robotic Hand

Several models have been developed for rehabilitation and mimicking of human hands for prosthesis. There are different designs and structures that have been modeled and implemented. Soft robotics has taken its toll on many applications in the biomedical field. However, there is still ongoing research in modeling anthropomorphic designs. This paper presents a preliminary work on a method of modeling a pneumatically actuated soft robotic hand which uses finite element analysis with simplicity of homogenous silicone material. The model presented has been fabricated and characterized in order to obtain a response that could mimic the bending of the human hand. A simple PID controller was used to control the air pressure applied in each joint for the evaluation. A vision system was set up to track the node coordinates of the soft pneumatic bending actuator (sPBA) finger. The kinematic equations of a hyper-redundant structure were used to estimate the bending angle of each joint. The results show that comparing the bending angle characteristic of the actual prototype and the FEM has an average error performance of 28.9° or 32.67% at joint 2 and 29.9° or 23.64% at joint 3. In terms of air pressure difference, 47 kPa or 34.07% is achieved in joint 2, and 33 kPa or 24% at joint 3 were achieved. Although these differences exist, the model was still able to achieve bending approximately 90° at each joint which can be useful for the development of a soft robotic hand.