Attitude Control Method of Serial Wheel-legged Robot

doi:10.12382/bgxb.2024.0183

Abstract

Abstract:

To address the precise attitude control of a serial wheel-legged robot,a motion control framework with offset-free model predictive control as the core is proposed.Firstly,a concentrated center-of-mass dynamics model is established,which considers the mass distribution of body,legs,and wheels.Based on the concept of active disturbance rejection control,the unmodeled characteristics of the model are treated as disturbances,and an extended state observer is established to estimate and compensate for the unmodeled characteristics.Furthermore,the joint control is introduced to solve the problem that the wheels are easy to roll and cause leg abduction during attitude adjustment,and an additional wheel control strategy is designed to assist in constraining the leg state.The hardware experiments are conducted on the serial wheel-legged robot.The results show that the proposed motion control framework can accurately track the desired attitude signal,effectively suppress the terrain disturbances and external force disturbances,and ensure the driving stability and disturbance resistance capability of the robot.

Key words: serial wheel-legged robot, attitude control, extended state observer, offset-free model predictive control

CLC Number:

TJ301

XIE Jingshuo, HAN Lijin, LIU Hui, REN Xiaolei, HOU Hongyu, SHANG Qingyi. Attitude Control Method of Serial Wheel-legged Robot[J]. Acta Armamentarii, 2025, 46(2): 240183-.

Figures/Tables 33

Fig.1 Serial wheel-legged robot

Table 1 Main parameters of the system

参数	数值
整体质量m/kg	65
大腿质量m_h/kg	3
小腿质量m_k/kg	2.5
车轮质量m_w/kg	2.5
大腿长度l_h/m	0.3
小腿长度l_k/m	0.3

Fig.2 Schematic diagram of leg kinematics analysis

Fig.3 Coordinate system of wheel-legged robot

Fig.4 Motion control framework

Fig.5 Wheel control strategy

Fig.6 Schematic diagram of assist torque effect

Fig.7 The slope estimation simulation scenes

Fig.8 The slope estimation simulation results

Fig.9 Simulated results of pitch disturbance observer

Fig.10 Simulated results of roll disturbance observer

Fig.11 The comparative simulation conditions

Fig.12 Attitude angles in sine signal simulation

Fig.13 Attitude angles in bilateral handicap simulation

Fig.14 Attitude angles in unilateral obstacle simulation

Fig.15 Attitude angles in impact disturbance simulation

Fig.16 Attitude angles in random road surface simulation

Fig.17 Comparison of attitude angles RMSEs

Fig.18 Communication architecture of wheel-legged robot control system

Fig.19 Pitch angle in attitude adjustment experiment

Fig.20 Roll angle in attitude adjustment experiment

Fig.21 The process of passing through the obstacles

Fig.22 Attitude angles in bilateral handicap experiment

Fig.23 Attitude angles in unilateral obstacle experiment

Fig.24 Experiment for resistance to external vertical disturbance

Fig.25 Attitude angles in vertical disturbance experiment

Fig.26 Disturbance estimation in vertical disturbance experiment

Fig.27 Experiment for resistance to external lateral disturbance

Fig.28 Attitude angles in lateral disturbance experiment

Fig.29 Disturbance estimation in lateral disturbance experiment

Fig.30 Experiment for resistance to external longitudinal disturbance

Fig.31 Attitude angles in longitudinal disturbance experiment

Fig.32 Disturbance estimation in longitudinal disturbance experiment

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