Design Principles for a Family of Direct-Drive Legged Robots

Kenneally, Gavin D.; De, Avik; Koditschek, Daniel E.

doi:10.1109/lra.2016.2528294

Cited by 273 publications

(196 citation statements)

References 27 publications

Supporting

Mentioning

195

Contrasting

Unclassified

Order By: Relevance

“…The spine is able to achieve a minimum hip-to-hip distance of 0.27m at maximum bending (20cm less than the hip-to-hip length at full extension), however for this work only moderate spine bending was used. The robot's legs consist of five-bar mechanisms driven by a pair of parallel direct-drive TMotor U8-16 brushless motors adapted from the design reported in [23].…”

Section: Quadrupedal Platformmentioning

confidence: 99%

Empirical validation of a spined sagittal-plane quadrupedal model

Duperret

Koditschek

2017

2017 IEEE International Conference on Robotics and Automation (ICRA)

View full text Add to dashboard Cite

Empirical validation of a spined sagittal-plane quadrupedal model AbstractWe document empirically stable bounding using an actively powered spine on the Inu quadrupedal robot, and propose a reduced-order model to capture the dynamics associated with this additional, actuated spine degree of freedom. This model is sufficiently accurate as to roughly describe the robots mass center trajectory during a bounding limit cycle, thus making it a potential option for low dimensional representations of spine actuation in steady-state legged locomotion. Disciplines Controls and Control Theory | Electrical and Computer Engineering | Engineering | RoboticsThis conference paper is available at ScholarlyCommons: http://repository.upenn.edu/ese_papers/786Empirical validation of a spined sagittal-plane quadrupedal model Jeffrey Duperret and Daniel E. Koditschek Abstract-We document empirically stable bounding using an actively powered spine on the Inu quadrupedal robot, and propose a reduced-order model to capture the dynamics associated with this additional, actuated spine degree of freedom. This model is sufficiently accurate as to roughly describe the robots mass center trajectory during a bounding limit cycle, thus making it a potential option for low dimensional representations of spine actuation in steady-state legged locomotion.

show abstract

Section: Quadrupedal Platformmentioning

confidence: 99%

Empirical validation of a spined sagittal-plane quadrupedal model

Duperret

Koditschek

2017

2017 IEEE International Conference on Robotics and Automation (ICRA)

View full text Add to dashboard Cite

show abstract

“…We further limit our discussion to the class of direct-drive quadrupedal robots whose legs are actuated by DC electric motors (as exemplified by [3] whose drivetrain technology and principles of design are roughly adopted in the hips of our new, additionally spined robot to be introduced in the next section). These robots sacrifice potential motor output shaft torque for high actuator and leg linkage transparency, allowing motors to sense environmental forces and events like ground contact.…”

Section: Technical Approach: the Utility Of Core Actuationmentioning

confidence: 99%

“…9 An established metric for evaluating the ability of a direct-drive limb to generate forces is thermal cost of force (for a normalized motor constant) given by the mean of the squared singular values of the forward kinematic Jacobian [14, page 48], [3]. As shown in the analysis above, in general smaller singular values are achievable by decreasing the length of lever arms in the (possibly parallel) kinematic chain to gain a greater mechanical advantage.…”

Section: Appendix 1: Analytic Leg Force Generation Versus Workpace Vmentioning

confidence: 99%

“…This paper demonstrates two advantages of introducing core actuation to a direct-drive quadrupedal robot and experimentally quantifies the utility of this morphological design choice. Specifically, we demonstrate that-in inherently torque-limited, direct-drive machines [14,3] where workspace volume and force generation are competing, scarce resources for operation in unstructured environments -the addition of core actuation increases workspace volume without adversely affecting leg force generation. Additionally, using gearing in the spine allows an individual motor to provide the mass center a significantly higher amount of sustained, work-producing force than it can on a transmission-free leg, without affecting leg linkage transparency.…”

Section: Introductionmentioning

confidence: 97%

“…While recent work in the field has yielded a growing array of impressive legged platforms capable of steady-state dynamic behaviors over flat or modest terrain [1,2,3,4], there has been less focus on designing systems for locomotion in highly irregular environments. In particular, there has been relatively little experimental investigation into the locomotion prowess of non-conventional legged robot morphologies (departing from the traditional rigid-body-with-appendages framework) such as core actuation that are commonly seen in animals operating in unstructured terrain.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Core Actuation Promotes Self-manipulability on a Direct-Drive Quadrupedal Robot

Duperret

Kramer

Koditschek

2017

Springer Proceedings in Advanced Robotics

View full text Add to dashboard Cite

For direct-drive legged robots operating in unstructured environments, workspace volume and force generation are competing, scarce resources. In this paper we demonstrate that introducing geared core actuation (i.e., proximal to rather than distal from the mass center) increases workspace volume and can provide a disproportionate amount of work-producing force to the mass center without affecting leg linkage transparency. These effects are analytically quantifiable up to modest assumptions, and are demonstrated empirically on a spined quadruped performing a leap both on level ground and from an isolated foothold (an archetypal feature of unstructured terrain). Abstract. For direct-drive legged robots operating in unstructured environments, workspace volume and force generation are competing, scarce resources. Disciplines Electrical and Computer Engineering | Engineering | Systems EngineeringIn this paper we demonstrate that introducing geared core actuation (i.e., proximal to rather than distal from the mass center) increases workspace volume and can provide a disproportionate amount of work-producing-force to the mass center without affecting leg linkage transparency. These effects are analytically quantifiable up to modest assumptions, and are demonstrated empirically on a spined quadruped performing a leap both on level ground and from an isolated foothold (an archetypal feature of unstructured terrain).

show abstract

Parameters self‐turning controller fused with an adaptive nominal model for disturbance observer: Application to direct drive manipulator with significant payload changes

Liu,

Chen,

Xie

2024

Adaptive Control & Signal

View full text Add to dashboard Cite

SummaryThe direct drive manipulator, which directly links the joint shaft to the motor rotor, is susceptible to external disturbances and model perturbations. When the direct drive manipulator operates with varying payloads, the disturbance observer (DOB) with a constant nominal model struggles to achieve satisfactory performance. To minimize estimation errors caused by disturbance, enhance trajectory tracking accuracy, and improve system robustness, this article proposes a controller parameter self‐tuning strategy with settling time, fused with a nominal model adaptive disturbance observer. Specifically, by optimizing the gain coefficient of the model reference adaptive identification (MRAI), the significant changes in payload at the manipulator's end joint can be quickly and accurately estimated. The inertia introduced by the payload is then employed to continuously update the nominal model of the manipulator, incorporating information about the inertia of the coupling joints. In addition, the controller parameters are updated using a self‐tuning link with settling time, which guarantees that the closed‐loop characteristics of the system remain unaffected by payload changes. Finally, the proposed method was validated using a two‐joint direct drive manipulator. The results demonstrate the robustness of the proposed method in the presence of significant payload changes, and the accuracy of disturbance estimation and the tracking performance of the proposed control strategy is significantly improved.

show abstract

Design Principles for a Family of Direct-Drive Legged Robots

Cited by 273 publications

References 27 publications

Empirical validation of a spined sagittal-plane quadrupedal model

Empirical validation of a spined sagittal-plane quadrupedal model

Core Actuation Promotes Self-manipulability on a Direct-Drive Quadrupedal Robot

Parameters self‐turning controller fused with an adaptive nominal model for disturbance observer: Application to direct drive manipulator with significant payload changes

Contact Info

Product

Resources

About