An improved force-based impedance control method for the HDU of legged robots

Ba, Kaixian; Yu, Bin; Gao, Zhengjie; Zhu, Qiuguo; Ma, Guoliang; Kong, Xianwen

doi:10.1016/j.isatra.2018.09.002

Cited by 39 publications

(15 citation statements)

References 25 publications

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“…To verify the validity of the MVIC designed in Section III, the integral separation PI controller designed in the author's previous research [27], [29] is used as a comparison reference. Under each working condition shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…In previous research by the author, force control performance and its parameter sensitivity of the HDU were studied in many aspects, providing an accurate force control mathematical model for this paper [5], [27]. Moreover, the dynamic compliance of the position control system and the force control system of the HDU were researched, and a compliancereduced controller and compliance-enhanced controller were designed to improve the disturbance rejection ability of both the position and force control system [28], [29].…”

Section: Introductionmentioning

confidence: 99%

“…The closed-loop force control transfer block diagram of the HDU is shown in Fig. 2 The derivation in detail and performance analysis are presented in previous research by the author [27], [29]. In Fig.…”

Section: Introduction Of Hdu Force Control Systemmentioning

confidence: 99%

“…The right part contains a same servo valve-controlled cylinder and a force sensor which adopts force closed loop control. The detailed hydraulic schematic of the HDU test platform, hydraulic system composition and electric system composition, can be found in the author's previous research [27], [28]. Due to limited space, that research won't be listed in this paper.…”

Section: Experiments Of Mvic Performance a Introduction Of Hdu Pementioning

confidence: 99%

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Design and Application of MVIC for Hydraulic Drive Unit of Legged Robot

Liu

et al. 2019

IEEE Access

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A hydraulic drive unit (HDU), applied in each joint of a hydraulic driven legged robot, usually adopts the impedance control outer loop based on the hydraulic position or the force control inner loop during the motion process. When the hydraulic control adopts closed-loop force control, its control performance can directly determine the control performance of the impedance control outer loop. Therefore, it is significant to design a high-accuracy force control method aimed at HDUs. In this paper, aiming at the above research concept, the force control system of the HDU is introduced first, and the lack of the force control performance is studied under different working conditions on the HDU performance test platform. Second, a model-based variable input controller (MVIC) is designed to improve the force control performance. Finally, the control performance of the MVIC is verified on the HDU performance test platform. The experimental results show that the MVIC can greatly improve the force control accuracy under different working conditions and that the controller has good robustness. The above research results can provide important reference and lay the experimental foundation for force-based impedance control. INDEX TERMS Legged robot, hydraulic drive unit (HDU), force control, model-based variable input control (MVIC).

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introduction Of Hdu Force Control Systemmentioning

confidence: 99%

Section: Experiments Of Mvic Performance a Introduction Of Hdu Pementioning

confidence: 99%

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Design and Application of MVIC for Hydraulic Drive Unit of Legged Robot

Liu

et al. 2019

IEEE Access

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“…After that, with the support of microelectronics technology, the hydraulic control unit became able to integrate with microprocessor, electronic power amplifier and sensor. So, the dynamic control accuracy, intelligence, reliability and robustness of the hydraulic control unit were improved [1][2][3]. When industry entered the 21st century, the tremendous cost of labor and energy forced industry to develop towards energy conservation and intelligence.…”

Section: Introductionmentioning

confidence: 99%

Review and Development Trend of Digital Hydraulic Technology

Zhang

Kong

et al. 2020

Applied Sciences

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Since the emergence of digital hydraulic technology, it has achieved good results in intelligence, integration, energy saving, etc. After decades of development, and it has also attracted wide attention in the industry. However, for many years, the definition of digital hydraulic technology has differed between researchers, and there is no uniform definition. Such a situation affects the development of it to a certain extent. Therefore, this paper gives the exact definition of digital hydraulic technology based on a large number of researches on it. At the same time, the paper analyzes the research status and developmental process of the such a technology, and we forecast the development trend of it.

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Model predictive control of hydraulic drive unit considering input delay

Liu

Qiang

Kang

2021

Math Methods in App Sciences

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Hydraulic drive unit (HDU) is a typical actuator, but the characteristic of input delay hinders the application of many advanced control methods in HDU. First, in this paper, a mathematical model of HDU with input delay is established and the parameters are identified. Then, aiming at the input delay problem in HDU, a Smith estimated compensation model predictive control (SECMPC) strategy is proposed. On the one hand, the input delay state equation is employed to be a mathematical pattern for the state observation and predictive model. However, the combination between model predictive control (MPC) and Smith estimated compensation (SEC) is realized, the system state at k + d (d is the time delay coefficient) time is estimated in advance at k time to compensate the delay of the state. And then the prediction model based on input delay state equation is used for model prediction and rolling optimization. Thus, the delay system which is unstable is promoted to a stable system without delay. The effectiveness of SECMPC is proved with the HDU experiment and simulation; the maximum experimental displacement error of traditional MPC control is 15 mm, while that of SECMPC control is 8 mm. The SECMPC have some guiding significance for the control of systems with input delay.

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An improved force-based impedance control method for the HDU of legged robots

Cited by 39 publications

References 25 publications

Design and Application of MVIC for Hydraulic Drive Unit of Legged Robot

Design and Application of MVIC for Hydraulic Drive Unit of Legged Robot

Review and Development Trend of Digital Hydraulic Technology

Model predictive control of hydraulic drive unit considering input delay

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