This paper presents about design efforts of a human-sized quadruped robot leg for high energy efficiency, and verifications. One of the representative index of the energy efficiency is the Cost of Transport (COT), but increased in the energy or work done is not calculated in COT. In this reason, the input to the output energy efficiency should be also considered as a very important term. By designing the robot with customized motor housing, small rotational inertia, and low gear ratio to reduce friction, high energy efficiency was achieved. Squatting motion of one leg was performed and simulation results were compared to the experimental results for validation. The developed 50 kg robot can lift the weight up to 200 kg, and during squatting, it showed high energy efficiency. The robot showed 71% input to output energy efficiency in positive work. Peak current during squatting only appears to be 0.3 A.

Abstract
 1. 서 론
 2. 설계 요구사항
 3. 설계 원리
  3.1 모터의 설계와 제작
  3.2 회전식 구동 전달
  3.3 작은 회전 관성을 위한 다리
 4. 로봇 다리의 제어
 5. 에너지 효율적인 로봇 다리의 실험적 검증
  5.1 스쿼트 실험
  5.2 시뮬레이션과 실험의 비교 검증
 6. 결 론
 사 사
 References

• 염호연(UNIST, Ulsan, Korea) | Hoyeon Yeom
• Dang Xuan Ba(UNIST, Ulsan, Korea)
• 배준범(Mechanical Engineering, UNIST, Ulsan, Korea) | Joonbum Bae Corresponding author