Softkinematic

Softkinematic is a term used to describe the study of motion, configuration, and transformation of soft, deformable, and compliant bodies. It extends classical kinematics, which addresses rigid bodies, to systems in which shape change is integral to movement, such as silicone or elastomer actuators, soft grippers, and compliant transmission elements. The term is used primarily in soft robotics and continuum robotics to capture challenges unique to deformable mobility.

In softkinematic analysis, the state of a system is often described by deformation fields or shape parameters rather than fixed joints. Models can be finite-dimensional, using a small number of parameters to capture large-scale shape changes, or continuum-based, representing the body as fields over space.

Common modeling approaches include Cosserat rod theory and other continuum mechanics formulations, Kirchhoff beam models, finite element methods, and spline or modal decompositions. Researchers use shape spaces and differential geometry to define poses and motions, while solving inverse problems to determine actuator inputs that achieve a desired shape or end-effector pose.

Applications span soft manipulation, compliant grippers, flexible surgical devices, and haptics. Softkinematic methods enable trajectory planning, pose estimation, contact handling, and control under large deformations, often in combination with sensing and data-driven models.

Key challenges include the effectively infinite degrees of freedom of soft bodies, measurement and model uncertainty, real-time computation, and robust control under deformation and contact. Ongoing work focuses on integrating sensing, learning-based models, and efficient solvers to make softkinematic techniques practical for design and operation of soft systems.