Parallel robots exhibit superior precision to serial robots. They operate with reduced power consumption due to load distribution among individual motors. However, symmetrical parallel robots employing a 1T2R structure encounter challenges with parasitic movements at the end-effector, leading to control complexities and application limitations. This study aimed to downsize the robot while ensuring its operational range by employing origami techniques. Addressing the inherent weakness of origami’s stiffness, various methods of material stacking and designed joints with diverse materials and thicknesses were proposed to meet specific angle requirements for each component. The developed control model was validated through simulations and experiments, effectively minimizing parasitic movements by verifying the robot"s motion.

The soft robotics field, known to have actuators and systems with a simple manufacturing process, being lightweight and safe to interact with humans, is in constant expansion. Present actuators have excessive unwanted deformations, which greatly affects the system"s performance by enlarging the external dimensions of the soft robot, reducing its efficiency, and causing unexpected or harmful contact with its surrounding environment. Thus, this work presented an actuator with a spring-like structure within a pneumatic chamber able to contract based on its innate design and lengthen when hyper-atmospheric pressures are applied, resulting in tension and torsion. A tensile testing machine and a force-torque sensor coupled with the actuator were used to evaluate its performance for different initial lengths, pressure inputs, and number of coils. At 30 kPa, a torque of up to 5 Nm was generated, have a maximum torsional angle of 41 degrees, and expanded 700% of its original length. Results have shown that the studied pneumatic-based expanding torsional soft spring actuator can stably lengthen under pneumatic pressure, resulting in sufficient force and considerable torque, and could be considered in future applications.