Model-based force control for motion and force tracking faces significant challenges on real quadruped platforms due to the apparent model inaccuracies. In this paper, we present a multi-objective optimal torque control for hydraulic quadruped robots under significant model errors, such as non-modelable hydraulic components, linearization, disturbances, etc. More specifically, the centroidal dynamics are first modeled to project the dynamics of the floating-based whole-body behaviors to the centroidal frame. Model error compensation mechanisms are subsequently developed to track the reference motion of the CoM, torso, and foot-end trajectories, which are mapped into the joint space. Furthermore, a multi-objective optimal torque control scheme is formulated using quadratic programming (QP) to coordinate follow the reference motion and ground reaction forces simultaneously while satisfying all constraints. Finally, we present a series of simulations as well as experiments on a real hydraulic quadruped platform, EHbot. The results demonstrate that the proposed torque control scheme is robust to large model inaccuracies and improves the performance of the overall system.
Hydro-viscous clutch has become an inevitable choice for the transmission of contemporary and future special vehicles. As a nonlinear dynamic system with large lagging link, its timing performance is affected by input rotational speed, lubricating oil temperature, lubricating pressure and other factors. However, in the actual application process, the actual influence of the influencing factors on the system performance is often judged by engineering experiences. From the control point of view, the speed regulation law and formation mechanism of hydro-viscous speed control system(HSCS) are not clear, and the control characteristics and global model are indeterminate. To solve the above problems, this paper analyzes the speed control characteristics of HSCS, including steady-state speed control characteristics and dynamic speed control characteristics. The specific characteristic parameters are obtained, and the data-driven model describing the input rotational speed, output speed, control oil pressure and lubricating oil temperature is established. The formation mechanism of the multi-region in HSCS is analyzed. According to the analysis, this paper determines that the effective pressure control range of HSCS is 0-6.2 Bar, the effective force control range is 0–4 KN, the fastest response time is greater than 3s. This paper provides the basis for integrated modeling and control method design. It is helpful to further reveal and obtain the control characteristics and parameters of HSCS, so as to provide the basis for the structure and parameter optimization, performance evaluation and analysis of HSCS machinery and hydraulic system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.