This paper presents the design and experimental validation of a torque-controlled robotic wrist for peg-in-hole tasks. The proposed wrist features a serial pitch-yaw joint configuration that enhances dexterity while maintaining compactness. The design integrates stepper motors, harmonic geartrains, and compliant mechanisms to optimize torque output and control accuracy. A compliant pulley and a compliant cap are introduced, enabling embedded torque sensing without the need for external sensors, thereby reducing system complexity and improving response time. Experimental results demonstrate the effectiveness of the wrist in torque accuracy and misalignment correction during peg-in-hole assembly, highlighting the benefits of the compliant-driven torque sensing approach. Compared to existing robotic wrists, the proposed design achieves a higher torque density. The findings contribute to advancing robotic wrist technology, particularly in applications requiring precise force modulation, high dexterity, and adaptable compliance.

Various sensorized grippers have been developed to handle delicate objects safely. These grippers have sensors mounted on their fingers’ surface that provide direct force measurements. However, multiple sensors are often required on one finger, leading to significant sensor placement and wire routing complexity. Finger-based sensors are limited to sensing external gripping force, and fingers cannot be easily replaced to meet the requirements of objects with specific geometries. To overcome the complexity and limitations of finger surface sensors, this paper proposes a force-controlled two-fingered gripper that relies on the deformation sensing of elastic elements in the drivetrain to obtain finger force. By using a minimum number of optical encoders placed in the drivetrain, accurate position and force sensing can be achieved at any location of each finger. When gripping an object, the size and stiffness of the object can thus be accurately measured. Simulation and experimental results demonstrate the proposed gripper’s merits. We expect this new gripper to provide a more competitive solution for robots that need to manipulate objects and check their mechanical qualities at the same time.