Hierarchical optimization for Whole-Body Control of Wheeled Inverted Pendulum Humanoids

Zafar, Munzir; Hutchinson, Seth; Theodorou, Evangelos A.

doi:10.1109/icra.2019.8794360

Cited by 31 publications

(15 citation statements)

References 46 publications

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“…They performed operational space control of the manipulator by isolating its dynamics from the wheelbase. Theodorou et al further worked on the hierarchical optimization for whole-body control of the WIP robot and successfully implemented it in simulations [16]. Yueyang et al proposed the whole-body control of a WIP robot based on a distributed dynamic model that consisted of the torso model, wheel-leg model, and contact force constraint between the wheels and ground in simulation [17].…”

Section: A Related Workmentioning

confidence: 99%

Balance Stability Augmentation for Wheel-Legged Biped Robot Through Arm Acceleration Control

2021

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A self-balancing wheel-legged robot provides higher maneuverability and mobility than legged biped robots. For this reason, wheel-legged systems have attracted enormous interest from academia and commercial sectors in recent years. Most of the past works in this field mainly focused on lower body stabilization. Motivated by the human ability to maintain balance in laborious activities by articulating the arm actively, we explore and analyze the active arm control on top of the wheel-legged system to assist in its balance recovery during external pushes and disturbances. This paper presents a control framework to improve the stability and robustness of an underactuated self-balancing wheel-legged robot using its upper limb arm. Furthermore, we use the centroidal moment pivot (CMP) as a key metric to quantitatively evaluate the effect of the active arm usage on the balance stability improvement of the robot in the ROS-Gazebo environment. The difference from the case of nonusage of arm is verified to clarify the impact of the active arm quantitatively. This concept would lead to the wheel-legged biped robot with an active arm for dual purposes, one is for carrying objects, another is for increasing the balance stability. This point is important for future application in a real-world environment with human-robot interactions.INDEX TERMS Wheel-legged robots, wheeled inverted pendulum (WIP), underactuated robots, motion control, balance recovery, stability analysis, disturbance rejection.

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Section: A Related Workmentioning

confidence: 99%

Balance Stability Augmentation for Wheel-Legged Biped Robot Through Arm Acceleration Control

2021

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“…In the MPC literature, a considerable effort has been put in showing real world applications on high dimensional systems [18], but current approaches struggle with the problem of high computational cost. A way to address this issue is to plan center of mass trajectories for a reduced linear inverted pendulum model ( [5], [19], [20]). These methods do not take into account the end-effector position and orientation tasks in the MPC planner.…”

Section: A Related Workmentioning

confidence: 99%

Whole-Body MPC for a Dynamically Stable Mobile Manipulator

Minniti

Farshidian

Grandia

et al. 2019

IEEE Robot. Autom. Lett.

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Autonomous mobile manipulation offers a dual advantage of mobility provided by a mobile platform and dexterity afforded by the manipulator. In this paper, we present a wholebody optimal control framework to jointly solve the problems of manipulation, balancing and interaction as one optimization problem for an inherently unstable robot. The optimization is performed using a Model Predictive Control (MPC) approach; the optimal control problem is transcribed at the end-effector space, treating the position and orientation tasks in the MPC planner, and skillfully planning for end-effector contact forces. The proposed formulation evaluates how the control decisions aimed at end-effector tracking and environment interaction will affect the balance of the system in the future. We showcase the advantages of the proposed MPC approach on the example of a ball-balancing robot with a robotic manipulator and validate our controller in hardware experiments for tasks such as end-effector pose tracking and door opening.

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“…Hutter et al [29] treated the inverse dynamics problem as a quadratic programming (QP) problem and provided an optimization method to solve inverse dynamics problems with constraints. Zafar et al [30] applied QP whole-body dynamics control to the wheeled humanoid robot with an arm and realized low-level centroid tracking control under the constraint of the joint torque. Klemm et al [31] extended the wheeled-foot sliding equilibrium capability under non-minimum phase dynamics by considering LQR control as a constraint condition of the QP problem.…”

Section: Introductionmentioning

confidence: 99%

Sliding Balance Control of a Point-Foot Biped Robot Based on a Dual-Objective Convergent Equation

Gao

Shi

et al. 2021

Applied Sciences

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The point-foot biped robot is highly adaptable to and can move rapidly on complex, non-structural and non-continuous terrain, as demonstrated in many studies. However, few studies have investigated balance control methods for point-foot sliding on low-friction terrain. This article presents a control framework based on the dual-objective convergence method and whole-body control for the point-foot biped robot to stabilize its posture balance in sliding. In this control framework, a dual-objective convergence equation is used to construct the posture stability criterion and the corresponding equilibrium control task, which are simultaneously converged. Control tasks are then carried out through the whole-body control framework, which adopts an optimization method to calculate the viable joint torque under the physical constraints of dynamics, friction and contact forces. In addition, this article extends the proposed approach to balance control in standing recovery. Finally, the capabilities of the proposed controller are verified in simulations in which a 26.9-kg three-link point-foot biped robot (1) slides over a 10∘ trapezoidal terrain, (2) slides on terrain with a sinusoidal friction coefficient between 0.05 and 0.25 and (3) stands and recovers from a center-of-mass offset of 0.02 m.

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Hierarchical optimization for Whole-Body Control of Wheeled Inverted Pendulum Humanoids

Cited by 31 publications

References 46 publications

Balance Stability Augmentation for Wheel-Legged Biped Robot Through Arm Acceleration Control

Balance Stability Augmentation for Wheel-Legged Biped Robot Through Arm Acceleration Control

Whole-Body MPC for a Dynamically Stable Mobile Manipulator

Sliding Balance Control of a Point-Foot Biped Robot Based on a Dual-Objective Convergent Equation

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