Passive dynamic walking model with upper body

Wisse, Martijn; Schwab, A. L.; Helm, F.C.T. van der

doi:10.1017/s0263574704000475

Cited by 138 publications

(97 citation statements)

References 15 publications

(23 reference statements)

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“…Particularly, it has to predict orientation of the upper body (which can be measured by IMUs) as well as the base of support and location and velocity of the CoM with respect to it (critical determinants of balance). Many models focus on foot placement only and reduce the upper body to a point mass, such that sensor information from the upper body (like inclination) cannot be integrated (Wisse et al, 2004;Hof, 2008). Also, many models consider double-support phases during gait as instantaneous, which greatly reduces the base of support.…”

Section: Introductionmentioning

confidence: 99%

Observing the State of Balance with a Single Upper-Body Sensor

2016

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The occurrence of falls is an urgent challenge in our aging society. For wearable devices that actively prevent falls or mitigate their consequences, a critical prerequisite is knowledge on the user's current state of balance. To keep such wearable systems practical and to achieve high acceptance, only very limited sensor instrumentation is possible, often restricted to inertial measurement units at waist level. We propose to augment this limited sensor information by combining it with additional knowledge on human gait, in the form of an observer concept. The observer contains a combination of validated concepts to model human gait: a spring-loaded inverted pendulum model with articulated upper body, where foot placement and stance leg are controlled via the extrapolated center of mass (XCoM) and the virtual pivot point (VPP), respectively. State estimation is performed via an Additive Unscented Kalman Filter (Additive UKF). We investigated sensitivity of the proposed concept to model uncertainties, and we evaluated observer performance with real data from human subjects walking on a treadmill. Data were collected from an Inertial Measurement Unit (IMU) placed near the subject's center of mass (CoM), and observer estimates were compared to the ground truth as obtained via infrared motion capture. We found that the root mean squared deviation did not exceed 13 cm on position, 22 cm/s on velocity (0.56-1.35 m/s), 1.2°on orientation, and 17°/s on angular velocity.Keywords: human gait and balance, wearable sensors, state estimation, virtual pivot point, extrapolated center of mass, capture point, additive unscented kalman filter, fall detection

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Section: Introductionmentioning

confidence: 99%

Observing the State of Balance with a Single Upper-Body Sensor

2016

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“…Wisse et al studied a simple passive dynamic walking model with an upper body that is confined to the midway angle of the two legs. The model can walk down a slope without motor input or control, 20,21 and by considering that the energy consumption of walking has a relationship with the slope angle, as gravity is the only means of energy input, Wisse et al showed that for a fixed walking speed and step length, an increase in the mass or length of the upper body will provide an even higher walking efficiency. Therefore, adding an upper body has a positive influence on walking efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…Although human beings do not have such a kinematic coupling, the assembly of pelvic muscles and reflexes could possibly perform a similar function. 20 This coupling mechanism can also be easily realized in robot systems.…”

Section: Introductionmentioning

confidence: 99%

Effects of upper body parameters on biped walking efficiency studied by dynamic optimization

Fang

et al. 2016

International Journal of Advanced Robotic Systems

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Walking efficiency is one of the considerations for designing biped robots. This article uses the dynamic optimization method to study the effects of upper body parameters, including upper body length and mass, on walking efficiency. Two minimal actuations, hip joint torque and push-off impulse, are used in the walking model, and minimal constraints are set in a free search using the dynamic optimization. Results show that there is an optimal solution of upper body length for the efficient walking within a range of walking speed and step length. For short step length, walking with a lighter upper body mass is found to be more efficient and vice versa. It is also found that for higher speed locomotion, the increase of the upper body length and mass can make the walking gait optimal rather than other kind of gaits. In addition, the typical strategy of an optimal walking gait is that just actuating the swing leg at the beginning of the step.

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“…A passive dynamic walking model incorporated with an upper body can be made to exhibit stable walking motion [13]. Chyou et al [14] reported that adding a torso to the compass-gait walker improves stability and walking speed when walking downhill.…”

Section: Introductionmentioning

confidence: 99%

Dynamics, stability, and actuation methods for powered compass gait walkers

Şafak¹

2014

Turk J Elec Eng & Comp Sci

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Abstract:In this paper, methods to achieve actively powered walking on level ground using a simple 2-dimensional walking model (compass-gait walker) are explored. The walker consists of 2 massless legs connected at the hip joint, a point mass at the hip, and an infinitesimal point mass at the feet. The walker is actuated either by applying equal joint torques at the hip and ankle, by an impulse applied at the toe off, immediately before the heel strike, or by the combination of both. It is shown that actuating the walker by equal joint torques at the hip and ankle on level ground is equivalent to the dynamics of the passive walker on a downhill slope. The gait cycle for the simplified walker model is determined analytically for a given initial stance angle. Stability of the gait cycle by an analytical approximation to the Jacobian of the walking map is calculated. The results indicate that the short-period cycle always has an unstable eigenvalue, whereas stability of the long-period cycle depends on selection of the initial stance angle. The effect of the torso mass by adding a third link attached at the hip joint is investigated. The torso link is kept in the vertical position by controlling the torque applied to it. The proportional-derivative control law is utilized to regulate the angular position error of the torso link. Using linearized dynamics for this walker, active control is applied to the ankle, which reduces the dynamics of the walker to the passive walker without the torso. The proposed walker is capable of producing stable walking while keeping the torso in an upright position.

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Passive dynamic walking model with upper body

Cited by 138 publications

References 15 publications

Observing the State of Balance with a Single Upper-Body Sensor

Observing the State of Balance with a Single Upper-Body Sensor

Effects of upper body parameters on biped walking efficiency studied by dynamic optimization

Dynamics, stability, and actuation methods for powered compass gait walkers

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