Tactile Mechatronic Systems

Inspired by the human sense of touch with its Golgi tendon - an organ for measuring muscle tension in the human musculoskeletal system - or tactile perception in the skin, designing robots with proprioceptive force/torque sensing in their joints and link structure as well as sensory skins at the surface level endows them with the tactile capabilities to sensitively and safely interact with their environment via tactile control. The research we conduct in this area considers the synergistic integration of mechanical engineering, sensory systems, electronics, and control in the design of complex mechatronic systems for tactile robots. This ranges from torque controlled drives and viscoleastic actuators to tactile exoprostheses and hands; together with methods for proprioceptive and tactile sensing, high performance communication and high-fidelity control.

Contributions

Collaborative and Tactile Robots depicts the tactile robot platforms to which development our group contributed to. Our work has lead to the design of state-of-the-art highly integrated torque-controlled and elastic actuators and lightweight robots capable of elegant physical interaction with their surroundings. Early works covered the DLR lightweight robot III (LWR-III) [171, 172], which later formed the basis of the well-known humanoid DLR-systems Justin [173] and Toro [174]. Later, the DLR hand-arm system HASy with with variable stiffness actuators (VSA) in every joint was developed [175]. This mimics the human musculoskeletal system in terms of variable passive joint compliance and the elastic energy storage during highly-dynamic energy-efficient motions and tasks. We proposed novel soft actuator concepts for tactile robots with torque control [176]. Further examples are tendon-driven humanoid wrists [177] or the recently introduced Bi-Stiffness Actuator (BSA)[13]. The latter incorporate clutches and multi-articular actuation for dynamic manipulation. It enables link decoupling to precisely store elastic energy in the joint, giving direct control over energy transfer timing.

The most noted example of our work is the Franka Emika Robot [38], the world’s first commercial and fully safety certified tactile robot. In contrast to classical collaborative robots, the Franka Emika Robot was designed to be fully force-controlled to enable the sensing of even the slightest contact with the environment and react with compliant and safe behavior. This philosophy was further developed into Garmi [178], a humanoid robot conceived to assist the elderly with activities of daily living.

AutoEvolve

To build a systematic framework for the co-evolution of embodiment and intelligence in robotics, our group currently introduces the scientific foundation of a new principle coined the AutoEvolve Cycle. First works focus on the automatic specification, design and AI-empowered construction of robot fingertips [180]. Overall, the AutoEvolve Cycle structures the advancing co-evolution of embodiment and intelligence into five phases leveraging the cooperative intelligence of human and artificial intelligence. They cover i.) the AI-assisted design of the robot, which generates the blueprint of the next robot generation, ii.) the construction of the robot platform, also by making use of AI-based and optimization methods, iii.) the understanding of the self and the world to generate models of the embodiment and the environment, iv.) the establishment of the ability to interact, control, and plan to enable the robot to execute complex policies and v.) the evaluation of the skills of the robot with respect to the defined R-Levels.