Testing Static Equilibrium for Legged Robots

Bretl, Timothy; Lall, Sanjay

doi:10.1109/tro.2008.2001360

Cited by 147 publications

(146 citation statements)

References 28 publications

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“…The dynamic controller maintained the DHM's balance by imposing that the horizontal plane projection of the centre of mass (com) lied within a convex support region (Bretl and Lall, 2008).…”

Section: Human-like Dynamic Dhm Controlsmentioning

confidence: 99%

Dynamic digital human models for ergonomic analysis based on humanoid robotics techniques

Magistris¹,

Micaelli²,

Savin³

et al. 2015

IJDH

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Digital human models can be used for biomechanical risk factors assessment of a workstation and work activity design for which there is no physical equipment that can be tested using actual human postures and forces. Yet, using digital human model software packages is usually complex and time-consuming. A challenging aim therefore consists in developing an easy-to-use digital human model capable of computing dynamic, realistic movements and internal characteristics in quasi-real time, based on a simple description of future work tasks, in order to achieve reliable ergonomics assessments of various work task scenarios. We developed such a dynamic digital human model, which is automatically controlled in force and acceleration and inspired by human motor control and based on robotics and physics simulation. In our simulation framework, the digital human model motion was controlled by real-world Newtonian physical and mechanical laws. We also simulated and assessed experimental insert-fitting activities according to the occupational repetitive actions (OCRA) ergonomic index. Simulation led to satisfactory results: experimental and simulated ergonomics evaluations were consistent, and both joint torques and digital human model movements were realistic and coherent with human-like behaviours and performances.

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Section: Human-like Dynamic Dhm Controlsmentioning

confidence: 99%

Dynamic digital human models for ergonomic analysis based on humanoid robotics techniques

Magistris¹,

Micaelli²,

Savin³

et al. 2015

IJDH

View full text Add to dashboard Cite

show abstract

“…In many cases, a convex hull described by the contact points of the robot's supporting feet is taken as a good approximation of this region. But it was shown by Bretl and Lall (2008) that it is an insufficient assumption in the free multi-leg gaits. The CM of the robot must satisfy constraints represented by Eqns.…”

Section: 5mentioning

confidence: 99%

“…All vectors are expressed in the global coordinate system x 0 , y 0 , z 0 . A solution to the robot static equilibrium problem requires a projection of a nonlinear convex set onto a two-dimensional subspace as described by Bretl and Lall (2008). This can be done by using a Second Order Cone Program (SOCP) (Lobo et al, 1998) specified in (23).…”

Section: 5mentioning

confidence: 99%

“…, Bretl and Lall (2008) use an adaptive algorithm called PROJECT to approximate the support region by the inscribed and prescribed polygon, having the number of edges dependent on the complexity of the convex set geometry. In our work, the approximation of the support region with a 16-edge polygon is used (Walas, 2009).…”

Section: 5mentioning

confidence: 99%

“…The solution proposed by Bretl and Lall (2008) was taken as the starting point in our research. The method of finding a support region was adapted to the case of a sixlegged walking robot.…”

mentioning

confidence: 99%

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Supporting locomotive functions of a six-legged walking robot

Walas¹,

Belter²

2011

International Journal of Applied Mathematics and Computer Science

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This paper presents a method for building a foothold selection module as well as methods for the stability check for a multi-legged walking robot. The foothold selection decision maker is shaped automatically, without expert knowledge. The robot learns how to select appropriate footholds by walking on rough terrain or by testing ground primitives. The gathered knowledge is then used to find a relation between slippages and the obtained local shape of the terrain, which is further employed to assess potential footholds. A new approach to function approximation is proposed. It uses the leastsquares fitting method, the Kolmogorov theorem and population-based optimization algorithms. A strategy for re-learning is proposed. The role of the decision support unit in the control system of the robot is presented. The importance of the stability check procedure is shown. A method of finding the stability region is described. Further improvements in the stability check procedure due to taking into account kinematic correction are reported. A description of the system for calculating static stability on-line is given. Methods for measuring stance forces are described. The measurement of stance forces facilitates the extended stability check procedure. The correctness of the method is proved by results obtained in a real environment on a real robot.

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Control Strategies for Soft Robot Systems

Wang

Chortos

2022

Advanced Intelligent Systems

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Soft robots have recently attracted increased attention because their characteristics of low‐cost fabrication, durability, and deformability make them uniquely suited for applications in bio‐integrated systems. Being fundamentally different from traditional rigid robots, soft robots exhibit properties of infinite degrees of freedom (DOF) and nonlinear materials properties that require innovations in control systems. With the rapid development of materials science, robotics, and artificial intelligence, the diversification of actuator mechanisms and algorithms has enabled a wide range of unique control strategies. This review summarizes the basics of actuator mechanisms and control strategies, including open‐loop control, closed‐loop control, and autonomous control, and discusses their implementation from diversified perspectives. Control strategies are evaluated based on their compatibility with materials sets, application goals, and implementation route. The emerging directions are forecasted from the perspectives of interfacing between controller and actuator, underactuated control strategies, and implementation of artificial intelligence (AI).

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Testing Static Equilibrium for Legged Robots

Cited by 147 publications

References 28 publications

Dynamic digital human models for ergonomic analysis based on humanoid robotics techniques

Dynamic digital human models for ergonomic analysis based on humanoid robotics techniques

Supporting locomotive functions of a six-legged walking robot

Control Strategies for Soft Robot Systems

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