Dynamic analysis and decoupled control of a heavy-duty walking robot with flexible feet based on super twisting algorithm

Ren, Huanhuan; Zhang, Lizhong; Su, Chengzhi

doi:10.1177/0020294020974059

Cited by 4 publications

(8 citation statements)

References 18 publications

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“…Liu et al [4] introduced an online foot position compensator (FPC) to minimize interference for humanoid robots. In [5], a strategy using a computational torque controller (CTC) and second-order sliding mode mitigates the position deviation and system vibration. In [6], the proposed method for a whole-body control frame-based biped robot ensured a stable sliding posture by optimizing the contact force, considering dynamics, friction, and constraints.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Tracking in Legged Robots through Model Reduction and Hybrid Control Techniques: Addressing Disturbances, Delays, and Saturation

Zhao,

Wang,

Cao

et al. 2024

Applied Sciences

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This study introduces a reduced-order leg dynamic model to simplify the controller design and enhance robustness. The proposed multi-loop control scheme tackles tracking control issues in legged robots, including joint angle and contact-force regulation, disturbance suppression, measurement delay, and motor saturation avoidance. Firstly, model predictive control (MPC) and sliding mode control (SMC) schemes are developed using a simplified model, and their stability is analyzed using the Lyapunov method. Numerical simulations under two disturbances validate the superior tracking performance of the SMC scheme. Secondly, an Nth-order linear active disturbance rejection control (LADRC) is designed based on a simplified model and optimization problems. The second-order LADRC-SMC scheme reduces the contact-force control error in the SMC scheme by ten times. Finally, a fourth-order LADRC-SMC with a Smith Predictor (LADRC-SMC-SP) scheme is formulated, employing each loop controller independently. This scheme simplifies the design and enhances performance. Compared to numerical simulations of the above and existing schemes, the LADRC-SMC-SP scheme eliminates delay oscillations, shortens convergence time, and demonstrates fast force-position tracking responses, minimal overshoot, and strong disturbance rejection. The peak contact-force error in the LADRC-SMC-SP scheme was ten times smaller than that in the LADRC-SMC scheme. The integral square error (ISE) values for the tracking errors of joint angles θ1 and θ2, and contact force f, are 1.6636×10−28 rad2⋅s, 1.7983×10−28 rad2⋅s, and 1.8062×10−30 N2⋅s, respectively. These significant improvements in control performance address the challenges in single-leg dynamic systems, effectively handling disturbances, delays, and motor saturation.

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Section: Introductionmentioning

confidence: 99%

“…This formula is also the general paradigm for a double-joint mechanical leg or arm (see References [5,9,14] in the Introduction). Where m 1 and m 2 are the masses of legs l 1 and l 2 ; l c1 and l c2 are half the lengths of legs l 1 and l 2 , respectively.…”

mentioning

confidence: 99%

Enhanced Tracking in Legged Robots through Model Reduction and Hybrid Control Techniques: Addressing Disturbances, Delays, and Saturation

Zhao,

Wang,

Cao

et al. 2024

Applied Sciences

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“…Recently, one of the most important approaches in SMC is to utilize the super-twisting algorithm (STA). [53][54][55][56][57][58][59] The ability to generate a continuous control signal is one of the prominent features of STA, thus reducing the overall chattering phenomenon. The STA is also a powerful tool in providing finite-time convergence to the origin of the sliding variables s and _ s. Moreover, the terminal sliding mode control is wellknown for its finite-time convergence of the state variables, which has been discussed in various research.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, one of the most important approaches in SMC is to utilize the super-twisting algorithm (STA). 53–59 The ability to generate a continuous control signal is one of the prominent features of STA, thus reducing the overall chattering phenomenon. The STA is also a powerful tool in providing finite-time convergence to the origin of the sliding variables σ and σ · .…”

Section: Introductionmentioning

confidence: 99%

Terminal super-twisting sliding mode based on high order sliding mode observer for two DOFs lower limb system

Tran

Duong

Nguyen

et al. 2023

Measurement and Control

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In this paper, a novel backstepping terminal super-twisting sliding mode (TSTSM) with high order sliding mode observer (HOSMO) is proposed to control the two degrees of freedom (DOFs) Serial Elastic Actuator (SEA), inspired by a lower limb of humanoid robots. First, the dynamic model, extended from our previous study, is presented for developing the control algorithm. Secondly, the backstepping technique is utilized to separate the overall system into two subsystems. One of the challenges of SEA is to deal with the evident oscillations caused by the elastic element, which might lead to the degrading performance of load position control. In order to reduce this adverse effect, a TSTSM is proposed to control the position tracking of two subsystems. The advantages of TSTSM are the finite-time convergence despite the bounded perturbation and the dramatic reduction of the chattering phenomenon. To construct and implement the TSTSM controller, it requires the knowledge of all states, which is not available in the current lower limb system setup. Therefore, a HOSMO is utilized to estimate the unknown states. Finally, experiment results are carried out to assess the effectiveness of the proposed controller and compare it with those of different control schemes.

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“…Due to the excessive dependence on the accurate system model, it is vulnerable to the influence of the uncertainty in the robot system, and the control accuracy of the trajectory tracking cannot be guaranteed in the robot control. [22][23][24][25][26] In order to reduce these uncertainties, Song et al 27 used the computed torque method to control the system with accurate dynamic parameters, and compensated for the modeling errors and external disturbances based on the fuzzy feedback controller, which ensured the stability of the closed-loop system. Chen et al 28 designed an adaptive feedforward fuzzy compensator and an adaptive feedback fuzzy compensator to compensate for the modeling errors and external disturbances on the basis of computed torque control, which effectively improved the control performance.…”

Section: Introductionmentioning

confidence: 99%

Trajectory tracking control strategy of the gantry welding robot under the influence of uncertain factors

Sun

Wang

et al. 2022

Measurement and Control

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In this paper, aiming at the problem of high-precision trajectory tracking of the gantry welding robot system under the influence of uncertain factors, a composite adaptive fuzzy compensation controller based on the computed torque control strategy has been proposed. The controller is composed of an adaptive fuzzy feedback control strategy and a dead zone adaptive fuzzy control strategy, which realizes high-precision trajectory tracking of the gantry welding robot, improves the solving speed of the control algorithm, and its tracking errors has been reduced. Screw theory and Lie group lie algebra are used to solve the problem of high algorithm complexity of controllers in multi-degree-of-freedom robot systems due to Newton-Euler dynamics modeling. Based on the computed torque control, the adaptive fuzzy feedback control strategy is adopted to compensate for the modeling errors and external disturbances in the gantry welding robot system, and the dead zone adaptive fuzzy control strategy is designed to compensate for the nonlinear dead zone structure with unknown parameters. The Lyapunov equation is introduced to prove the stability of the controller. Finally, the controller designed in this paper is compared with the conventional controller through simulation and experiment on the gantry welding robot platform, which verifies the effectiveness and superiority of the controller.

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Dynamic analysis and decoupled control of a heavy-duty walking robot with flexible feet based on super twisting algorithm

Cited by 4 publications

References 18 publications

Enhanced Tracking in Legged Robots through Model Reduction and Hybrid Control Techniques: Addressing Disturbances, Delays, and Saturation

Enhanced Tracking in Legged Robots through Model Reduction and Hybrid Control Techniques: Addressing Disturbances, Delays, and Saturation

Terminal super-twisting sliding mode based on high order sliding mode observer for two DOFs lower limb system

Trajectory tracking control strategy of the gantry welding robot under the influence of uncertain factors

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