A Torque-actuated dissipative spring loaded inverted pendulum model with rolling contact and Its application to hexapod running

Hu, Ching-Piao; Wang, Tso-Kang; Huang, Chun‐Kai; Lin, Pei-Chun

doi:10.1088/1748-3190/aafc4e

Cited by 10 publications

(9 citation statements)

References 29 publications

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“…Virtual damping requires high-frequency force control, and actuators mechanically and electrically capable of absorbing peaks in negative work. In comparison, mechanical damping based systems (Garcia et al, 2011;Hu et al, 2019) act instantaneously, share impact loads with the actuator when in parallel configuration, and require no sensors or control feedback. The instantaneous mechanical response of a damper is especially relevant in biological systems, where the neuronal delay may be as large as 5 % to 40 % of the duration of a stance phase (More et al, 2010).…”

Section: Figure 1 | (A-c)mentioning

confidence: 99%

Effective Viscous Damping Enables Morphological Computation in Legged Locomotion

Izzi

Haeufle

et al. 2020

Front. Robot. AI

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Muscle models and animal observations suggest that physical damping is beneficial for stabilization. Still, only a few implementations of physical damping exist in compliant robotic legged locomotion. It remains unclear how physical damping can be exploited for locomotion tasks, while its advantages as sensor-free, adaptive force-and negative work-producing actuators are promising. In a simplified numerical leg model, we studied the energy dissipation from viscous and Coulomb damping during vertical drops with ground-level perturbations. A parallel spring-damper is engaged between touchdown and mid-stance, and its damper auto-decouples from mid-stance to takeoff. Our simulations indicate that an adjustable and viscous damper is desired. In hardware we explored effective viscous damping and adjustability, and quantified the dissipated energy. We tested two mechanical, leg-mounted damping mechanisms: a commercial hydraulic damper, and a custom-made pneumatic damper. The pneumatic damper exploits a rolling diaphragm with an adjustable orifice, minimizing Coulomb damping effects while permitting adjustable resistance. Experimental results show that the leg-mounted, hydraulic damper exhibits the most effective viscous damping. Adjusting the orifice setting did not result in substantial changes of dissipated energy per drop, unlike adjusting the damping parameters in the numerical model. Consequently, we also emphasize the importance of characterizing physical dampers during real legged impacts to evaluate their effectiveness for compliant legged locomotion.

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Section: Figure 1 | (A-c)mentioning

confidence: 99%

Effective Viscous Damping Enables Morphological Computation in Legged Locomotion

Izzi

Haeufle

et al. 2020

Front. Robot. AI

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“…The leg was made up of a linear spring, a linear slider leg structure made of Polylactic acid, and tire tread, which provides the leg traction on the ground. The robot runs with an alternating tripod gait, the same as in other previous works [28,[30][31][32]. The motion trajectory of the robot leg in stance phase follows that of the optimal G-SLIP model.…”

Section: Experimental Implementation and Resultsmentioning

confidence: 99%

“…The model successfully served as a template for transient, steady-state, and variable-speed running by a robot. A torque-actuated, dissipative R-SLIP model was developed to analyze a robot's energy flow and transformation [31]. A physics-data hybrid motion template was designed to bridge the unmodeled discrepancy between the R-SLIP model and the robot [32].…”

Section: Introductionmentioning

confidence: 99%

The generalized spring-loaded inverted pendulum model for analysis of various planar reduced-order models and for optimal robot leg design

Lu,

Lin

2024

Bioinspir. Biomim.

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This paper proposes a generalized spring-loaded inverted pendulum (G-SLIP) model to explore various popular reduced-order dynamic models' characteristics and suggest a better robot leg design under specified performance indices. The G-SLIP model’s composition can be varied by changing the model’s parameters, such as ground contacting type and spring property. It can be transformed into four widely used models: the spring-loaded inverted pendulum (SLIP) model, the two-segment leg (TSL) model, the SLIP with rolling foot (SLIP-RF) model, and the rolling SLIP (R-SLIP) model. The effects of rolling contact and spring configuration on the dynamic behavior and fixed-point distribution of the G-SLIP model were analyzed, and the basins of attraction (BOA) of the four described models were studied. By varying the parameters of the G-SLIP model, the dynamic behavior of the model can be optimized. Optimized for general locomotion running at various speeds, the model provided leg design guidelines. The leg was empirically fabricated and installed on the hexapod for experimental evaluation. The results indicated that the robot with a designed leg runs faster and is more power-efficient.

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“…The model is suitable for a running robot whose leg features a rolling motion. In addition, the effect of clock-torqued [13] or torque and damping [14] on the R-SLIP model have been studied. In contrast to the use of one virtual leg in the template, some behaviors of legged animals require multileg templates so that the behavior can be correctly presented.…”

Section: Introductionmentioning

confidence: 99%

Dynamic turning and running of a hexapod robot using a separated and laterally arranged two-leg model

Chang¹,

Lin²

2023

Bioinspir. Biomim.

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We report on the development of separated and laterally arranged two-leg (SLTL) models with/without differentiated leg properties and their use as the dynamic running and turning templates for a hexapod robot. The laterally arranged two-leg morphology enables differential driving for turning. The differentiable leg settings, such as stiffness, enables the model to adopt unbalanced leg arrangements of empirical legged gaits, such as a tripod gait, into consideration. The fixed-point motion of the model was utilized as the main methodology to plan dynamic running and turning, in which the plot of one-step distance versus period was constructed for the legs’ operation point selection and matching. The proposed methodology was experimentally validated using four indices: turning curvature, flight phase, motion stability, and energy efficiency. The experimental results show that the running robot using the SLTL model with differentiated leg stiffness has better energy efficiency than one without by 4%, while the latter model has identical performance to the original spring-loaded inverted pendulum model with rolling contact. As for turning, the robot using the SLTL models with/without differentiated leg stiffness can preserve dynamic turning in all experiments with turning curvatures up to 0.28m^(-1) and 0.30m^(-1), respectively, 33% and 43% more than the robot using the original model-less phase-shift turning strategy (0.21 m^(-1)). Using the proposed model-based strategy, the flight phase of the robot turning in all curvatures (including straight running) maintains around 20%, the root-mean-squared (RMS) values of pitch and roll remains less than 3 deg, and the specific resistance (SR) is bounded between 0.64 and 0.73. By contrast, the robot using the phase-shifting turning strategy can maintain dynamic motion up to a turning curvature of 0.21 m^(-1). A further increase in phase shifting not only does not increase the turning curvature but also changes the robot motion from running to walking. In this case, no flight phase exists, the SR jumps up significantly, and RMS values of pitch and roll also increase dramatically. In short, the experimental validation confirms the effectiveness of the proposed methodology for initiating the dynamic running and turning of the robot.

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A Torque-actuated dissipative spring loaded inverted pendulum model with rolling contact and Its application to hexapod running

Cited by 10 publications

References 29 publications

Effective Viscous Damping Enables Morphological Computation in Legged Locomotion

Effective Viscous Damping Enables Morphological Computation in Legged Locomotion

The generalized spring-loaded inverted pendulum model for analysis of various planar reduced-order models and for optimal robot leg design

Dynamic turning and running of a hexapod robot using a separated and laterally arranged two-leg model

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