Robust state dependent Riccati equation variable impedance control for robotic force-tracking tasks

Roveda, Loris; Piga, Dario

doi:10.1007/s41315-020-00153-0

Cited by 24 publications

(13 citation statements)

References 37 publications

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“…In fact, Cartesian robot control is generally required for interaction applications, requiring estimating forces and torques acting at the robot end‐effector. Therefore, this virtual sensor can be also adopted for interaction control purposes 54 …”

Section: Extended Kalman Filter For External Wrench Estimationmentioning

confidence: 99%

Robot joint friction compensation learning enhanced by 6D virtual sensor

Roveda

Bussolan

Braghin

et al. 2022

Intl J Robust & Nonlinear

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High-performance robot control is one of the most investigated topics in both research and industry. Being able to compensate for robot dynamics is indeed one major challenge. Joint friction is commonly the main issue, especially in sensorless (i.e., no availability of torque/force sensors) compliance-controlled robots for interaction application purposes. The presented paper aims to propose a methodology for sensorless Cartesian impedance controlled robots to learn local friction compensation controllers. Exploiting a 6D virtual sensor to quantify the joint friction effects, a Bayesian optimization (BO)-based algorithm is proposed to minimize the estimated external interaction in free-motion tasks (related to friction effects). The BO algorithm enhances the impedance control performance by tuning the model-based friction compensator parameters.To validate the proposed approach, experimental tests have been executed on a Franka EMIKA panda robot, highlighting the suitability of the proposed 6D virtual sensor and BO-based algorithm to minimize the estimated external interaction for joint friction compensation purposes.

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Section: Extended Kalman Filter For External Wrench Estimationmentioning

confidence: 99%

Robot joint friction compensation learning enhanced by 6D virtual sensor

Roveda

Bussolan

Braghin

et al. 2022

Intl J Robust & Nonlinear

Self Cite

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“…It has to be highlighted that an observer for the estimation of the external interaction is proposed due to the fact that compliance control is employed. Therefore, this observer can be also adopted in order to close the control loop [44], [45], [34].…”

Section: External Joint Torques Estimationmentioning

confidence: 99%

“…order to implement the proposed optimal controller, a coupled robot-environment interaction dynamics has to be defined. To this purpose, the interaction environment is modeled as an elastic system (i.e., with a stiffness parameter K e,i as in [44]), making it possible to write the following coupled robot-environment dynamics in the state-space:…”

Section: Optimal Force Controlmentioning

confidence: 99%

Sensorless Optimal Switching Impact/Force Controller

et al. 2021

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Intelligent interaction control is required in many fields of application, in which different operative situations have to be faced with different controllers. Being able to switch between optimized controllers is, indeed, of extreme importance to maximize the task performance in the different operative conditions (i.e., free-space motion and contact), especially when considering sensorless robots. To deal with the proposed context, a sensorless optimal switching impact/force (OSIF) controller is proposed. The low-level robot control is composed of an inner joint position controller, fed by an outer Cartesian impedance controller with a reference position. The estimation of the external wrench is implemented by means of an Extended Kalman Filter (EKF). The high-level controller (feeding the Cartesian impedance controller with the setpoint) is composed of an optimized impact controller (LQR-based controller), an optimized force controller (SDREbased controller), and a continuous switching mechanism (Fuzzy Logic-based). In addition, the output of the switching mechanism is used to adapt the Cartesian impedance control parameters (i.e., stiffness and damping parameters). Experimental tests have been performed on a Franka EMIKA panda robot to validate the proposed controller. Obtained results show the capabilities of the OSIF controller, being able to detect task phase transitions while satisfying the target performance.

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“…troller has various advantages, its accuracy has difficulty meeting the requirements sembly tasks [13,14], so this paper does not pay attention to these methods.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, it can also be used in cases of unknown environments. Although the sensorless force controller has various advantages, its accuracy has difficulty meeting the requirements of assembly tasks [13,14], so this paper does not pay attention to these methods.…”

Section: Introductionmentioning

confidence: 99%

A Control Method of Space Manipulator for Peg-in-Hole Assembly Task Considering Equivalent Stiffness Optimization

et al. 2021

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To meet the control requirements of high precision and high robustness for peg-in-hole assembly tasks, an optimized control method for a peg-in-hole assembly task of a space manipulator is proposed to reduce the system disturbance caused by the change contact status during the assembly process. The first step is to build an equivalent stiffness model, which considers the structure and control characteristics of the space manipulator. Flexibility indices along the assembly direction are then created. On completion of the flexibility indices, the assembly configuration of the manipulator is optimized with the gain of the joint controller. After that, based on the sliding mode impedance control law, the disturbance of contact force is compensated using a zero-sum optimal control compensation strategy. Finally, the correctness and effectiveness of the control method are verified through simulation experiments. The results of the simulation experiments show that the contact force of the space manipulator can be precisely controlled by the method proposed in this paper. Compared with existing methods, the sudden change of contact force and the disturbing force of the base are reduced by 90% and 54%, respectively. A control method of the space manipulator for a peg-in-hole assembly task considering the equivalent stiffness optimization is proposed, which effectively reduces the influence of disturbance caused by contact collision and improves the control robustness of peg-in-hole assembly tasks.

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Robust state dependent Riccati equation variable impedance control for robotic force-tracking tasks

Cited by 24 publications

References 37 publications

Robot joint friction compensation learning enhanced by 6D virtual sensor

Robot joint friction compensation learning enhanced by 6D virtual sensor

Sensorless Optimal Switching Impact/Force Controller

A Control Method of Space Manipulator for Peg-in-Hole Assembly Task Considering Equivalent Stiffness Optimization

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