Series elastic robots are best able to follow trajectories which obey the limitations of their actuators, since they cannot instantly change their joint forces. In fact, their actuators can even allow them to improve over the performance of a robot with an ideal force source actuator by storing and releasing energy. In this paper, we formulate the trajectory optimization problem for series elas...

The diversity in torque-controlled actuators has enabled researchers to address numerous physical human–robot interaction applications with enhanced safety, dependability, and capability [1] . Yet, only a few meet the challenging application requirements of mobility,...

Series elastic actuators (SEAs) have had sound contributions in the robotics field, and significant breakthroughs been achieved. Despite this fact, there are still drawbacks to their performance. The spring, which provides compliance, limits SEA’s performance by lowering bandwidth of force/torque generation, decreases even further when SEA has render large torques. This problem originates from ...

A safe interaction is crucial in wearable robotics in general, while in assistive and rehabilitation applications, robots may also be required to minimally perturb physiological movements, ideally acting as perfectly transparent machines. The actuation system plays a central role because the expected performance, in terms of torque, speed and control bandwidth, must not be achieved at the expen...

In this paper, we propose a methodology to optimize the nonlinear stiffness of nonlinear Series Elastic Actuators (SEAs). The nonlinear restoring forces of the springs are optimized in order to minimize the mechanical power of the actuators of the SEAs. We define the cost function as the time average of the square of the actuator power, and use a 3 order Hermite interpolation to parameterize th...

A spinal cord injury (SCI) disrupts the motor and sensory functions of the nervous system, limitingmotion capabilities and reducing the quality of life of affected people. An active stance-control knee-ankle-foot orthosis was developed and tested to aid incomplete SCI subjects by increasing theirmobility and independence [1]. A further improvement of the orthosis is conducted by...

A safe interaction is crucial in wearable robotics in general, while in assistive and rehabilitation applications, robots may also be required to minimally perturb physiological movements, ideally acting as perfectly transparent machines. The actuation system plays a central role because the expected performance, in terms of torque, speed and control bandwidth, must not be achieved at the expen...

Tendon springs influence locomotor movements in many terrestrial animals, but their roles in locomotion through fluids as well as in small-bodied mammals are less clear. We measured muscle, tendon and joint mechanics in an elbow extensor of a small fruit bat during ascending flight. At the end of downstroke, the tendon was stretched by elbow flexion as the wing was folded. At the end of upstrok...

In this article we present a compact and modular device designed to allow a conventional stiff servo actuator to be easily upgraded into a series elastic actuator (SEA). This is a low cost, open source and open hardware solution including mechanical CAD drawings, circuit schematics, board designs and firmware code. We present a complete overview of the project as well as a case study where we s...