On the Feedback Linearization of Robots with Variable Joint Stiffness

Palli, Gianluca; Melchiorri, Claudio; Luca, Alessandro De

doi:10.1109/robot.2008.4543454

Cited by 111 publications

(129 citation statements)

References 18 publications

Supporting

Mentioning

125

Contrasting

Unclassified

Order By: Relevance

“…Among these are the singular perturbation-based approaches [26], decoupling-based approaches [19], [27], backstepping-based schemes [28], and the passivity-based approaches [29], [30] to mention a few. In the same context, combined position and stiffness control of variable stiffness robots is more recently investigated using (a decoupling-based) feedback linearizion [31], [32]. These approaches generally combine closed-loop motor position and velocity control with link-side feedback on positions, torques, and their derivatives.…”

mentioning

confidence: 99%

Robots Driven by Compliant Actuators: Optimal Control Under Actuation Constraints

et al. 2013

View full text Add to dashboard Cite

Abstract-Anthropomorphic robots that aim to approach human performance agility and efficiency are typically highly redundant not only in their kinematics but also in actuation. Variableimpedance actuators, used to drive many of these devices, are capable of modulating torque and impedance (stiffness and/or damping) simultaneously, continuously, and independently. These actuators are, however, nonlinear and assert numerous constraints, e.g., range, rate, and effort limits on the dynamics. Finding a control strategy that makes use of the intrinsic dynamics and capacity of compliant actuators for such redundant, nonlinear, and constrained systems is nontrivial. In this study, we propose a framework for optimization of torque and impedance profiles in order to maximize task performance, which is tuned to the complex hardware and incorporating real-world actuation constraints. Simulation study and hardware experiments 1) demonstrate the effects of actuation constraints during impedance control, 2) show applicability of the present framework to simultaneous torque and temporal stiffness optimization under constraints that are imposed by real-world actuators, and 3) validate the benefits of the proposed approach under experimental conditions.

show abstract

mentioning

confidence: 99%

Robots Driven by Compliant Actuators: Optimal Control Under Actuation Constraints

et al. 2013

View full text Add to dashboard Cite

show abstract

“…Thus, we suggest an adaptive reference tension, which is low during regular motion and is increased during the periods of switching (see Figure 7a). To control the joint position as well as the antagonist tension force, we use input-output feedback linearization [42] through a two-step compensator. Satisfactory results in controlling a single joint were achieved.…”

Section: Puller-follower Controlmentioning

confidence: 99%

Toward Anthropomimetic Robotics: Development, Simulation, and Control of a Musculoskeletal Torso

et al. 2013

View full text Add to dashboard Cite

A version of this paper with color figures is available online at http://dx.doi.org/10.1162/ artl_a_00088. Subscription required.Abstract Anthropomimetic robotics differs from conventional approaches by capitalizing on the replication of the inner structures of the human body, such as muscles, tendons, bones, and joints. Here we present our results of more than three years of research in constructing, simulating, and, most importantly, controlling anthropomimetic robots. We manufactured four physical torsos, each more complex than its predecessor, and developed the tools required to simulate their behavior. Furthermore, six different control approaches, inspired by classical control theory, machine learning, and neuroscience, were developed and evaluated via these simulations or in small-scale setups. While the obtained results are encouraging, we are aware that we have barely exploited the potential of the anthropomimetic design so far. But, with the tools developed, we are confident that this novel approach will contribute to our understanding of morphological computation and human motor control in the future.

show abstract

“…Recently, Palli et al [25], proposed a tracking control algorithm for such a flexible joint manipulator with variable stiffness actuation to achieve asymptotic tracking to the desired joint and stiffness trajectories based on inputoutput linearization, effectively an active cancellation of the intrinsic robot dynamics. Note that the main focus of [25] is the tracking control of the given joint and stiffness trajectories, and the problem of generating such desired trajectories for a given specific task is not addressed. On the other hand, if we rearrange the linearized dynamics of (1) (sin q ≈ q) as…”

Section: Passive Control Strategy In Swing Movementmentioning

confidence: 99%

Exploiting Passive Dynamics with Variable Stiffness Actuation in Robot Brachiation

Nakanishi¹,

Vijayakumar²

2012

Robotics: Science and Systems VIII

View full text Add to dashboard Cite

Abstract-This paper explores a passive control strategy with variable stiffness actuation for swing movements. We consider brachiation as an example of a highly dynamic task which requires exploitation of gravity in an efficient manner for successful task execution. First, we present our passive control strategy considering a pendulum with variable stiffness actuation. Then, we formulate the problem based an optimal control framework with temporal optimization in order to simultaneously find an appropriate stiffness profile and movement duration such that the resultant movement will be able to exploit the passive dynamics of the robot. Finally, numerical evaluations on a twolink brachiating robot with a variable stiffness actuator (VSA) model are provided to demonstrate the effectiveness of our approach under different task requirements, modelling errors and switching in the robot dynamics. In addition, we discuss the issue of task description in terms of the choice of cost function for successful task execution in optimal control.

show abstract

On the Feedback Linearization of Robots with Variable Joint Stiffness

Cited by 111 publications

References 18 publications

Robots Driven by Compliant Actuators: Optimal Control Under Actuation Constraints

Robots Driven by Compliant Actuators: Optimal Control Under Actuation Constraints

Toward Anthropomimetic Robotics: Development, Simulation, and Control of a Musculoskeletal Torso

Exploiting Passive Dynamics with Variable Stiffness Actuation in Robot Brachiation

Contact Info

Product

Resources

About