An inverse-universal-joint scheme for two-dimensional posture-adjusting turntable

The posture-adjustable turntable is playing an important part in testing equipments and other industrial devices. As well known, universal joint is employed to couple two parts that are aligned with a certain angle to transmit torque and speed. There are three major parts in a U-joint: active hinge, cross shaft, and passive hinge. Power is transmitted from the active hinge to the passive hinge via the cross shaft. It is observed that cross shaft is changing its posture continuously in the working process. Therefore, we conceived a novel idea that the posture of cross shaft can be controlled by means of adjusting both active hinge and passive hinge concurrently. A two-dimensional posture-adjustable turntable can be established by the use of this concept of inverse universal joint. The active and passive hinges are driven individually, and cross shaft may reach the desired posture. Based on the concept of inverse U-joint, kinematics analysis was conducted to obtain relationship between inputs of hinges and posture output of cross shaft. A prototype was developed based on the concept of inverse-U joint and experiments were conducted to verify the concept of inverse U-joint.