Optimal Design of the Modular Joint Drive Train for Enhancing Cobot Load Capacity and Dynamic Performance

Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of industries.Compared to the commonly used design approach of increasing the payload-to-weight ratio of cobot to enhance load capacity,equal attention should be paid to the dynamic response characteristics of cobot during the design process to make the cobot more flexible.In this paper,a new method for designing the drive train parameters of cobot is proposed.Firstly,based on the analysis of factors influencing the load capacity and dynamic response characteristics,design criteria for both aspects are established for cobot with all optimization design criteria normalized within the design domain.Secondly,with the cobot in the horizontal pose,the motor design scheme is discretized and it takes the joint motor diameter and gearbox speed ratio as optimization design variables.Finally,all the discrete values of the optimization objectives are obtained through the enumeration method and the Pareto front is used to select the optimal solution through multi-objective optimization.Base on the cobot design method proposed in this paper,a six-axis cobot is designed and compared with the commercial cobot.The result shows that the load capacity of the designed cobot in this paper reaches 8.4 kg,surpassing the 5 kg load capacity commercial cobot which is used as a benchmark.The minimum resonance frequency of the joints is 42.70 Hz.

DIRECT DIGITAL DESIGN AND SIMULATION OF MESHING IN WORM-GEAR DRIVE

A direct digital design method （DDDM） of worm-gear drive is proposed. It is directly based on the simulation of manufacturing process and completely different from the conventional modeling method. The loaded tooth contact analysis （LTCA） method is analyzed, in which the advanced surface to surface searching technique is included. The influence of misalignment errors and contact deformations on contact zone and transmission error （TE） is discussed. Combined modification approach on worm tooth surface is presented. By means of DDDM and LTCA, it is very conven- ient to verify the effect of worm-gear drive＇s modification approach. The analysis results show that, the modification in profile direction reduces the sensitivity of worm-gear drive to misalignment errors and the modification in longitudinal direction decreases the TE. Thus the optimization design of worm-gear drive can be achieved prior to the actual manufacturing process.

A Hybrid Si IGBT and SiC MOSFET Module Development

A compact wirebond packaged phase-leg SiC/Si hybrid module was designed,developed,and tested.Details of the layout and gate drive designs are described.The IC chip for gate drive is carefully selected and compared.Dual pulse test confirmed that,the switching loss of hybrid module is close to pure SiC MOSFET module,and it is much less than pure Si IGBT device.The cost of hybrid module is closer to Si IGBT.

The Impulse Excitation Joint Servo Drive Design and Adaptive Backstepping Control of Humanoid Robots

This study aims to explore the humanoid robot joint servo drive integration design and adaptive backstepping control. To make the humanoid robot have explosive power as the human does, simply increasing the power output of the motor of a lightweight design cannot meet the demand of moving heavy objects and so on. Moreover, the backstepping control algorithm is designed to implement the dual-arm cooperative control. The joint servo drive is redesigned in the present study, which can drive the motor at a limitation state when needed output high-voltage pulse can stimulate the motor so that the motor can produce an instantaneous large torque. A miniature design scheme is presented in this study for the servo drive, explaining the design method of each part module. The ex- perimental data illustrate that the servo drive can produce an output torque greater than the rate of the high-voltage pulse that stimulates the motor. Knowledge of the control of humanoid robot moving a heavy object has important practical significance. The present study provides a complete actual problem and exhibits a real practical use case which can be used to speed up the explosive humanoid robot arms.

Establishing distinctive theories and methods of design science rooted in Chinese traditional culture

The human social development saw the formation of five unique civilizations,with the latter forming their own distinctive cultures.China’s traditional culture is its most fundamental ideological weapon for solving problems.The Chinese are good at comprehensive thinking,dialectical thinking,and systematic analysis.These ideological weapons can solve the problems of formal science and technology and create scientific and technological achievements on par with global advanced scale.Ancient China is filled with original scientific and technological achievements,which strongly prove ancient China’s possession of its own science and technology different from that of Western Renaissance.Therefore,a comprehensive understanding of science,technology,experience,and intuition is necessary.The long-held superstition regarding the West,the lack of confidence,self-denial,blind imitation of ideas,and shackles must be thrown away.Only then can we take the road toward an authentic Chinese creative design as we learn from others.