Energy efficiency enhancement of SCORBOT ER-4U manipulator using topology optimization method

Abstract

Topology optimization is a promising technique to define holes and links in the material design space to reduce mass and inertial effect and enhance energy efficiency. In this work, topology optimization of the upper and forearm of SCORBOT ER-4U manipulator is performed considering dynamic loading conditions. The optimized topology corresponding to a loading condition may not be sufficient for other conditions because of changes in applied load directions. Here a methodology is applied to consolidate multiple optimized topologies at different angle values in working range. The superimposition technique is used to combine all the density elements of material domain. Later, highly sensitive elements of the material are refined using normalization followed by re-penalization approaches. It also helps to reduce volume and grayscale elements in the material domain. Due to this process, sharp corners, irregularities, and tiny holes persist in synthesized topology, which leads to the poor performance of the manipulator. Therefore, image morphology-based processing techniques are applied to eliminate the geometric complexities and improves the performance of a robot. The synthesized topology obtained using this methodology shows a 15–36.4% reduction in deflection and Von-Mises stress. The SCORBOT educational manipulator is considered to illustrate the proposed method. The complete manipulator is designed in SOLIDWORKS, and a motion study is conducted to generate the dynamic analysis data concerning the angular position. The manipulator-link volume fraction is reduced by 50%, which improves energy efficiency by 43.2% with better performance values.

Keywords:

• Articulated robot
• compliance
• energy-efficiency
• image processing
• industrial manipulator
• topology optimization

Appendix A

Table A1. Highest deflection and stress values of the SCORBOT upper arm at various angle values.

Appendix B

Table B1. Highest deflection and stress values of the SCORBOT forearm at various angle values.

Additional information

Funding

The work was supported by the “Department of Science and Technology (DST) – Science and Engineering Research Board (SERB), India” under grant No.: ECR/2017/000799.