Rolling based locomotion on rough terrain for a wheeled quadruped using centroidal dynamics

Abstract

This paper proposes a new wheel motion generator to track the centroidal motion of one quadrupedon-wheel robot which has the ability to cross various rough terrains with the model based wholebody torque control. The generator is used to track the whole-robot centroidal motion reference. Firstly, the wheel contact model and the whole-body inverse kinematics model are derived using spatial vectors. The wheel motion is extracted out mathematically depending on the base and the legged motions, which serves as the kinematics model. Then the wheel motion generator is developed by combining both the kinematics model and the robot centroidal momentum/dynamics model. The models are decomposed into three components relating to the base motion, the legged motion and the wheel motion. The adaptive wheel motion references are derived in a detailed mathematical way and several algorithms are developed for the model decompositions. Finally, the robot is simulated to be driven on various rough terrains using the operational space control framework mixed with our proposed compatible prioritized impedance controller. The required torque for multiple tasks is generated by the feed-forward and feedback controllers while fulfilling the contact constraints.

Motion control framework for unmanned wheel-legged hybrid vehicle considering uncertain disturbances based robust model predictive control

“…As shown in Figure 2, the upper leg is driven by the hip joint BLDC actuator directly, the lower leg is driven by the knee joint actuator by the timing belt. Compared with some existing wheel-legged robot, the designed configuration of each wheel-legged system for the UWLHV has the hip flexion/extension joint, the knee flexion/extension joint, and the wheel forward/backward joint, excluding the hip abduction/adduction joint (Bjelonic et al, 2019; Du et al, Nov 2020). Based on the Denavit and Hartenberg method, the world frame is constructed which can be denoted as {X,Y,Z}, the frame system for the contact point of the front-left wheel and ground can be denoted as {fiX,fiY,fiZ} of the UWLHV, as shown in Figure 2.…”

Kinematic modeling and hybrid motion planning for wheeled-legged rovers to traverse challenging terrains

“…Du et al. [17] present a model taking into account wheel mobility and rolling-based locomotion for a wheel-legged robot using centroidal dynamics. Wheel velocity and acceleration are derived by both the legged motion and the CoM translation motion reference.…”

“…Han et al [16] propose a unified kinematic modeling method for reconfigurable landing and roving probes with full consideration of six-dimensional foot-terrain interaction. Du et al [17] present a model taking into account wheel mobility and rolling-based locomotion for a wheel-legged robot using centroidal dynamics. Wheel velocity and acceleration are derived by both the legged motion and the CoM translation motion reference.…”

Attitude control strategy for unmanned wheel-legged hybrid vehicles considering the contact of the wheels and ground

“…As the most widely type, wheeled vehicles have the competitive advantages of high maneuverability and low energy consumption, which limited in off-road and rough road driving scenarios. [2][3][4] The legged vehicles have the benefits of environmental adaptability and flexibility, which can achieve complex tasks such as crossing ditches and vertical obstacles. 5 However, the legged vehicles have some disadvantages, such as low mobility, low carrying capacity, and high energy consumption.…”

“…Each leg is composed of the higher leg, lower leg, and a wheel, and the wheel is mounted at the end of the lower leg. Compared with the other styles, 2,11,13 each leg of the UWLHVs has three joints, including the hip joint, the knee joint, and the wheel joint, excluding the hip abduction/adduction joint for the UWLHVs. Therefore, a hierarchical attitude control strategy for the UWLHVs is proposed in the paper.…”