Serieselastic

Serieselastic is a term used in mechanical engineering and robotics to describe systems that employ a compliant element placed in series with an actuator. The core idea is to introduce controlled elasticity between the drive and the load, enabling safer interaction with environments and more precise force regulation.

In a typical serieselastic arrangement, an actuator—such as a motor, hydraulic, or pneumatic device—drives a shaft connected in series with a spring or other elastic element. Sensors measure actuator position and spring deformation to estimate output force and to close a torque or impedance control loop. The elastic element stores and releases energy, increasing shock tolerance and smoothing force transients.

Applications span robotics, prosthetics, and haptic devices, especially where safe contact, tactile feedback, or delicate manipulation is required. Benefits include improved force fidelity, enhanced backdrivability, passive energy storage, and better disturbance rejection. Limitations include nonlinear spring behavior, hysteresis, temperature sensitivity, wear, and added mechanical complexity that can complicate calibration and maintenance.

Related concepts include series elastic actuators and compliant control strategies, with ongoing research exploring nonlinear and variable-stiffness elements, smart materials, and adaptive control to extend performance and reliability in dynamic tasks.