Joint torque control for two-inertia system with encoders on drive and load sides

Yamada, Shota; Inukai, Kenji; Fujimoto, Hiroshi; Omata, Kenji; Takeda, Yuki; Makinouchi, Susumu

doi:10.1109/indin.2015.7281767

Cited by 27 publications

(7 citation statements)

References 15 publications

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“…12 Recent studies using feedback and feedforward control for flexible-joint robots are presented in refs. [13][14][15]. However, feedforward gains are determined by a very complicated backstepping process in ref.…”

Section: Review On Control Approaches For Flexible-joint Robotsmentioning

confidence: 99%

A Two-Stage State Feedback Controller Supported by Disturbance-State Observer for Vibration Control of a Flexible-Joint Robot

et al. 2019

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SUMMARYJoint flexibility introduces additional degrees of freedom and vibration modes, thus limiting the performance of the manipulator. To improve control bandwidth, this paper proposes an enhanced two-stage state feedback (SFB) controller, which combines two parts. The first is a SFB loop, which considers the motor position as a virtual control input for the link side dynamics. The second is a disturbance-state observer, which compensates disturbances and reconstructs indirect measurements. Experimental results show the effectiveness of the proposed controller in terms of position tracking, link vibration, and rejection of the kinematic error from the joint’s harmonic drive reducer.

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Section: Review On Control Approaches For Flexible-joint Robotsmentioning

confidence: 99%

A Two-Stage State Feedback Controller Supported by Disturbance-State Observer for Vibration Control of a Flexible-Joint Robot

et al. 2019

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“…The setup consists of two motors with 20-bit encoders, a joint torque sensor, and a gear coupling. These days, the control methods using load-side encoder are gaining a lot of attentions, and our research group has proposed a novel structure with load-side encoder for industrial robots' application in [12]. Based on the industrial trend that the number of load-side encoders is increasing, we assume that load-side encoder of the load-side motor can be used for feedback control.…”

Section: B Piecewise Affine Modelmentioning

confidence: 99%

Piecewise affine (PWA) modeling and switched damping control of two-inertia systems with backlash

Yamada

Ruderman

Fujimoto

2018

2018 IEEE 15th International Workshop on Advanced Motion Control (AMC)

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Backlash degrades positioning accuracy and can induce mechanical wear and breakage by collisions. Therefore, a lot of studies have been conducted on backlash compensation. The simplest control method for the impact attenuation is torsional damping addition by feedback of torsional velocity. This paper reveals the advantages and disadvantages of the torsional damping addition. Based on the analyses, a novel switched damping control is proposed to realize the responses with smaller overshoot while attenuating the impact. The mechanical system and the proposed controller are described as piecewise affine systems for analyses. The performance of the proposed method is compared with a linear damping control method in simulations and experiments.

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“…However, it is quite difficult to create a model-based compensator such as the joint torque control proposed by Yamada et al (26) because of the complexity of modeling hydraulic systems. From (2) and (3), backlash and oil leakage can be observed as relative velocity between the load-side and the motor-side Δω.…”

Section: Backlash and Oil Leakage Compensatormentioning

confidence: 99%

Reaction Force Estimation of Electro-hydrostatic Actuator Using Reaction Force Observer

et al. 2018

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Electro-hydrostatic actuators (EHAs) are hydraulic actuators that are flexible and exhibit high backdrivability. Flexible operation and accurate detection of reaction forces are required for robots to be able to perform in environments in which they will be cohabiting with humans. However, nonlinear elements that degrade detection accuracy, such as static friction, backlash, and oil leakage, are present in hydraulic systems. In addition, pressure sensors in hydraulic systems are not very accurate at estimating reaction forces, because they cannot estimate internal forces and viscous friction. In this study, we propose a combination of control algorithms for accurately estimating reaction forces. Static friction is compensated by using feedback modulators. In addition, we use a backlash and oil leakage compensator, which do not require any models, to suppress the relative velocity between the motor-side and load-side. Then, the use of a reaction force observer (RFOB) that exploits both pressure sensors and encoders is proposed. The RFOB can be implemented because disturbances are linearized by the compensators. Experimental results show that reaction forces can be estimated with very high accuracy using the proposed RFOB. In addition, we implemented force control using the RFOB and evaluate the force tracking performances by improving the estimation accuracy.

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Joint torque control for two-inertia system with encoders on drive and load sides

Cited by 27 publications

References 15 publications

A Two-Stage State Feedback Controller Supported by Disturbance-State Observer for Vibration Control of a Flexible-Joint Robot

A Two-Stage State Feedback Controller Supported by Disturbance-State Observer for Vibration Control of a Flexible-Joint Robot

Piecewise affine (PWA) modeling and switched damping control of two-inertia systems with backlash

Reaction Force Estimation of Electro-hydrostatic Actuator Using Reaction Force Observer

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