Abstract: To reduce structural modifications and minimize the impact on legged locomotion, this paper presents SlidBot, a quadruped robot with roller-skating capability, designed to improve movement efficiency on sloped surfaces. Two passive wheels without braking mechanisms are installed on the knee joint and lower leg of the robot. During quadruped movement, these wheels remain off the ground and therefore do not interfere with locomotion. The brakeless design reduces the number of components and simplifies the mechanical structure. When roller skating motion is required, simply adjust the leg posture to make the passive wheel on the lower leg contact the ground. The roller skating mode of the robot can be divided into two-legged roller skating and four-legged roller skating. During two-legged roller skating, the passive wheels of the hind legs support the ground, and the front legs execute backward propulsion to provide power for the robot’s movement. In four-legged roller skating, both the front and hind legs’ passive wheels contact the ground, resulting in a large supporting area and a low center of gravity, which helps maintain stability during high-speed movement and facilitates passage through low-lying environments. This paper outlines the robot design method, establishes a kinematic model, plans the gait and mode-switching method. Simulation and physical results indicate that the robot can perform stable diagonal trotting and roller skating movements. Moreover, on flat terrain, the roller skating motion is more energy-efficient than diagonal trotting, and on slopes, its energy and motion efficiency significantly surpasses that of the diagonal trot. This research offers novel insights for quadruped robot design and can considerably enhance the movement efficiency of quadruped robots on sloped terrains.

Key words: Quadruped robot, Leg-wheel mechanism, Passive wheel, Roller skating, Slope movement')">Quadruped robot, Leg-wheel mechanism, Passive wheel, Roller skating, Slope movement