Journal of Bionic Engineering ›› 2023, Vol. 20 ›› Issue (1): 291-307.doi: 10.1007/s42235-022-00269-y
Spring-Loaded Inverted Pendulum Hopping via Hybrid Averaging and Control Lyapunov Function
Hao Sun1; Junjie Yang1; Yinghao Jia1; Qinghua Li1; Changhong Wang1
- 1 Space Control and Inertial Technology Research Center, Harbin Institute of Technology, Harbin 150001, China
Spring-Loaded Inverted Pendulum Hopping via Hybrid Averaging and Control Lyapunov Function
Hao Sun1; Junjie Yang1; Yinghao Jia1; Qinghua Li1; Changhong Wang1
- 1 Space Control and Inertial Technology Research Center, Harbin Institute of Technology, Harbin 150001, China
摘要： The Spring-Loaded Inverted Pendulum (SLIP) has been regarded as a canonical model for hopping and running dynamics of legged robots. This paper presents a novel control of the actuated-SLIP hopping on unknown terrains. We propose that in the neighborhood of the desired stable hybrid limit cycle, the local dynamical behavior of a hybrid system can be expressed by a set of phase coordinates and transverse coordinates. Under some acceptable assumptions, the hybrid averaging theorem is applied on the SLIP non-integrable dynamics to simplify the controller design. Using the inherent symmetry of SLIP dynamics, a control Lyapunov function-based hybrid averaging controller is developed to ensure the exponential stability of the desired gait orbit. This results in a set of linear constraints on the control signal, which can be readily solved by a quadratic programming optimization. Furthermore, a novel method is introduced to improve the robustness against unknown disturbances through the online constraint adjustment. The proposed controller is evaluated in various simulations, demonstrating the SLIP hopping on diverse terrains, including flat, sin-wave, and unregular terrains. The performance of the approach is also validated on a quadruped robot SCIT Dog for generating dynamic gaits such as pronking.