**Kun Yang, Xuewen Rong, Lelai Zhou \* and Yibin Li**

Center for Robotics, School of Control Science and Engineering, Shandong University, No. 17923, Jingshi Road, Jinan 250061, China; yangkundtc@gmail.com (K.Y.); rongxw@sdu.edu.cn (X.R.); liyb@sdu.edu.cn (Y.L.) **\*** Correspondence: zhoulelai@sdu.edu.cn; Tel.: +86-0531-8839-6083

Received: 19 March 2019; Accepted: 25 April 2019; Published: 28 April 2019

**Abstract:** Energy consumption is an important performance index of quadruped robots. In this paper, the energy consumptions of the quadruped robot SCalf with a trot gait under different gait parameters are analyzed. Firstly, the kinematics and dynamics models of the robot are established. Then, an energy model including the mechanical power and heat rate is proposed. To obtain the energy consumption, a cubic spline interpolation foot trajectory is used, and the feet forces are calculated by using the minimization of norm of the foot force method. Moreover, an energetic criterion measuring the energy cost is defined to evaluate the motion. Finally, the gait parameters such as step height, step length, standing height, gait cycle, and duty cycle that influence the energy consumption are studied, which could provide a theoretical basis for parameter optimization and motion control of quadruped robots.

**Keywords:** quadruped robot; energy model; foot force distribution; cubic spline interpolation
