Statically balanced brakes

Plooij, Michiel; Hoeven, Tom van der; Dunning, Gerard; Wisse, Martijn

doi:10.1016/j.precisioneng.2015.09.013

Cited by 9 publications

(3 citation statements)

References 12 publications

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“…To realize a non-linear spring characteristic, we adapt the cam mechanism used in [23]. The shape of the cam is computed using the method in [24].…”

Section: B Notes Towards Realizationmentioning

confidence: 99%

Unparameterized Optimization of the Spring Characteristic of Parallel Elastic Actuators

Spaa

Wolfslag

Wisse

2019

IEEE Robot. Autom. Lett.

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In electrically actuated robots most energy losses are due to the heating of the actuators. This energy loss can be greatly reduced with parallel elastic actuators, by optimizing the elastic element such that it delivers most of the required torques. Previously used optimization methods relied on parameterizing the spring characteristic, thereby limiting the set of spring characteristics optimized over and with that the loss reduction that can be obtained. This paper shows that such parametrization is not necessary; a method is presented to compute the optimal characteristic as an analytic function of the trajectory. The efficacy of this method is demonstrated using two examples. The first example considers the optimal spring characteristic for a parallel elastic actuator supporting the human ankle during walking. The second example applies the method in combination with trajectory optimization on a single degree of freedom robot performing a specific pick-andplace task. The task at hand has a height difference between the pick and the place location. With the analytical optimal spring, it is shown that the robot can recover enough of the energy released by the package to function without external electric energy supply.

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“…To realize a non-linear spring characteristic, we adapt the cam mechanism used in [23]. The shape of the cam is computed using the method in [24].…”

Section: B Notes Towards Realizationmentioning

confidence: 99%

Unparameterized Optimization of the Spring Characteristic of Parallel Elastic Actuators

Spaa

Wolfslag

Wisse

2019

IEEE Robot. Autom. Lett.

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“…The main challenge is to make clutches with a high torque density and low energy consumption and can lock at every position. Recent clutch designs include piezoelectric clutches [49], statically balanced brakes [50] and electro static clutches [32].…”

Section: Componentsmentioning

confidence: 99%

Clutched Elastic Actuators

Plooij

Wolfslag

Wisse

2017

IEEE/ASME Trans. Mechatron.

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Abstract-This paper identifies the class of actuators called clutched elastic actuators (CEAs). CEAs use clutches to control the energy flow into springs. CEAs in exoskeletons, prostheses, legged robots and robotic arms have shown the ability to reduce the energy consumption and motor requirements such as peak torque and peak power. Because of those abilities, they are increasingly used in robotics. In this paper, we categorize existing CEA designs, identify trends in those designs and provide a method to analyze their functionality. Based on a literature survey, current CEA designs are placed in nine categories, depending on their morphology. The main trend is that CEA designs are becoming more complex, meaning that the number of clutches and springs increases. We show with the introduced mathematical analysis that the functionality can be analyzed with a constraint matrix, a stiffness matrix and multiplication of a clutch dependent diagonal matrix with an oriented incidence matrix. This method eases the analysis of the functionality of CEAs. Furthermore, it can lead to new CEA designs in which the number of resulting stiffnesses grows exponentially with the number of springs and clutches.

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“…A friction based locking mechanism that completely decouples the friction force and the actuation force is the statically balanced brake by Plooij et al [78] (see Fig. 3d).…”

Section: Statically Balanced Brakesmentioning

confidence: 99%

Lock Your Robot: A Review of Locking Devices in Robotics

Plooij

Mathijssen

Cherelle

et al. 2015

IEEE Robot. Automat. Mag.

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133

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Locking devices are widely used in robotics, for instance to lock springs, joints or to reconfigure robots. This review paper classifies the locking devices currently described in literature and preforms a comparative study. Designers can, as such, better determine which locking device best matches the needs of their application. The locking devices are divided into three main categories based on different locking principles: mechanical locking, friction-based locking and singularity locking. Different lockers in each category can be passive lockers or active lockers. Based on an elaborate literature study, the paper summarizes the findings by comparing different locking devices, based on a set of properties of a theoretical ideal locking device.

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Statically balanced brakes

Cited by 9 publications

References 12 publications

Unparameterized Optimization of the Spring Characteristic of Parallel Elastic Actuators

Unparameterized Optimization of the Spring Characteristic of Parallel Elastic Actuators

Clutched Elastic Actuators

Lock Your Robot: A Review of Locking Devices in Robotics

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