The High-payload Manipulator Development Based on Novel Two-stage Cycloidal Speed Reducers and Hub Motors

Abstract

Collaborative robots such as Universal Robotics and KUKA are well developed and well known throughout the world. Nowadays, the manipulator structure uses a brushless motor with an RV reducer, or a harmonic reducer, and has a built-in driver to form a joint module and is composed of a connecting rod. This paper proposes a four-axis manipulator based on the novel two-stage cycloidal reducers and hub motors. The traditional two-stage cycloidal speed reducer requires two cycloidal gears through the first-stage speed reducer. Therefore, the traditional two-stage cycloidal reducer has four cycloidal gears. The novel two-stage cycloidal speed reducer simplifies this design. The design of the secondary deceleration is achieved by connecting two different numbers of cycloidal teeth and a phase difference of 180 degrees to the intermediate central disc so that the two-stage speed reduction can be achieved, and the reduction ratio is 136. Use this type of speed reducer, with a 200W hub motor, to build a four-axis manipulator and place a driver in the rod to save space. The proposed manipulator specifications: 4 degrees of freedom, the maximum payload is 18kg, the total weight is 37kg, the maximum working space is 0.7 meters, the efficiency of the reducer is 73.657% and the backlash of the reducer is 1.135°. The features of this four-axis manipulator are lightweight, low power, low cost, high-payload, and long life. This type of reducer is also a new option in addition to RV reducer and harmonic reducer for driving manipulator’s joint.