3 DOF Robotic Wrist with Ball-and-Socket Joint Mechanism

The human wrist is a complex anatomical structure, which imposes challenges for replication in the robotics industry. In a study conducted by Beren et al. (2012) titled "Application of Universal Joint for Simultaneous Robotic Wrist Movement," researchers devised a solution. They utilized a configuration of motors to create a three-degree-of-freedom universal joint resembling the human wrist. This involved four motors for pitch and yaw control, along with an additional motor for roll motion. Through extensive testing, they successfully achieved robotic movements resembling those of the human wrist. Another study, made by Rudio et al. (2016), entitled "Application of Microsoft Xbox One for Mimicking Robotic Wrist with Three Degrees of Freedom in Different Poses", used a universal joint using strategically placed servomotors to mimic the human wrist movement. The problem with these designs is the used of multiple joints to cater for the three degrees of freedom the human wrist has. To address this issue, a proposed solution involves incorporating a ball joint mechanism within the robotic wrist, enabling it to replicate the full range of motion that the human wrist can do. With the factors considered in designing the robotic wrist, the design achieved an average angle difference of +/- 1.80 in terms of pitch motion. In yaw motion, the robotic wrist design achieved an average of +/-0.84, and an average angle difference of +/-1.26 in terms of roll motion. Overall, the design achieved an average of +/-0.1 angle difference in all movements.