WW

W.J. Wolfslag

20 records found

Authored

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 optimizati ...

The main task of robotic grippers, holding an object, does not require work theoretically. Yet grippers consume significant amounts of energy in practice. This paper presents an approach for designing an energy-saving drive for robotic grippers employing a Statically Balanced ...

Robots would perform better when their mechanical structure is specifically designed for their designated task, for instance by adding spring mechanisms. However, designing such mechanisms, which match the dynamics of the robot with the task, is hard and time consuming. To assist ...

Effective robot arm motions

Stability and efficiency through natural dynamics

While progress in many fields of robotics has been swift, robot arm movement in scenarios without contact has changed little in the last decades. This lack of change is not due a lack of potential for improvement. After all, the human arms that these robot emulate move in ways th ...

The boundaries of walking stability

Viability and controllability of simple models

From which states and with what controls can a biped avoid falling or reach a given target state? What is the most robust way to do these? So as to help with the design of walking robot controllers, and perhaps give insights into human walking, we address these questions using ...

RRT-CoLearn

Towards kinodynamic planning without numerical trajectory optimization

Sampling-based kinodynamic planners, such as Rapidly-exploring Random Trees (RRTs), pose two fundamental challenges: computing a reliable (pseudo-)metric for the distance between two randomly sampled nodes, and computing a steering input to connect the nodes. The core of these ch ...
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 re ...

Contributed

Kinodynamic planning is motion planning in state space and aims to satisfy kinematic and dynamic constraints. To reduce its computational cost, a popular approach is to use sampling based methods such as RRT with off-line machine learning for estimating the steering cost and inpu ...
The novelty-raahn algorithm has been shown to effectively learn a desired behavior from raw inputs by connecting an autoencoder with a Hebbian network. Hebbian learning is compelling for its biological plausibility and simplicity. It changes the weight of a connection based only ...
Kinodynamic motion planning for a robot involves generating a trajectory from a given robot state to goal state while satisfying kinematic and dynamic constraints. Rapidly-exploring Random Trees (RRT) is a sampling-based algorithm that has been widely adopted for this. However, R ...
Nowadays, the number of robotic systems grows enormously. In order to execute their task, many of these robots need a fixturing gripper to grasp and hold objects. To reduce the environmental impact, the operational costs, the size of actuators and to improve the uptime of mobile ...
Current robots consume a lot of energy. The work required for a task is generally just a tiny fraction of the total energy consumed. Most energy wastefully dissipated. Design of the 2 degree of freedom (DoF) Plugless Robot Arm shows that clever design can reduce these energy loss ...

Contesting Conservatism with Complexity

Exploring Linear Relaxations of the Positivstellensatz for Robust Stability Analysis of Nonlinear Systems

Lyapunov's 2nd method can be formulated as a convex optimization problem by means of Sum-of-Squares (SOS) optimization. This gives a powerful tool for robust stability analysis of nonlinear systems. The use of SOS optimization is limited to small dynamical systems, because of the ...