Jiefeng Sun

Colorado State University | CSU · Mechanical Engineering

In nature, animals or insects can leverage the same body parts for different functions (e.g., a frog can use its legs to walk, jump, and swim). But robots, especially miniature ones, can normally perform a single task with a fixed mechanical design. In this paper, we propose a novel strategy to enable reconfigurable robots by embedding shape morphi...

Various actuators (e.g., pneumatics, cables, dielectric elastomers, etc.) have been utilized to actuate soft robots. Besides widely used actuators, a relatively new artificial muscle-twisted-and-coiled actuators (TCAs)-is promising for actuating centimeter-scale soft robots because they are low-cost, have a large work density, and can be driven by...

Twisted and coiled actuators (TCAs) have recently emerged as a promising artificial muscle for various robotic applications because they are strong, low-cost, and customizable. To better facilitate the applications, it is critical to establish general and precise models for different types of TCAs (e.g., self-coiled, free-stroke, conical, etc.). Al...

Soft robots have been intensively investigated for manipulation and locomotion in recent years. However, the current state of soft robotics has significant design and development work but lags in modeling and control due to the difficulty in modeling them. In this paper, we present a physics-based analytical framework to model soft robots driven by...

The recent global outbreaks of epidemics and pandemics have shown us that we are severely under-prepared to cope with infectious agents. Exposure to infectious agents present in biofluids (e.g., blood, saliva, urine etc.) poses a severe risk to clinical laboratory personnel and healthcare workers, resulting in hundreds of millions of hospital-acqui...

Perching onto objects can allow flying robots to stay at a desired height at low or no cost of energy. This paper presents a novel passive mechanism for aerial perching onto smooth surfaces. This mechanism is made from a bistable mechanism and a soft suction cup. Different from existing designs, it can be easily attached onto and detached from a su...

Perching onto an object (e.g., tree branches) has recently been leveraged for addressing the limited flight time for flying robots. Successful perching needs a mechanical mechanism to damp out the impact and robustly grasp the object. Generally, such a mechanism requires actuation for grasping. In this paper, we present a fully passive mechanism wi...

Traditional soft robots require separate sensors and actuators to precisely control their motion. A twisted-and-coiled actuator (TCA) is a new artificial muscle with both actuation and self-sensing capability that can simultaneously serve both as a sensor and an actuator allowing to control the motion of TCAs without external sensors. This paper in...

Soft machines typically exhibit slow locomotion speed and low manipulation strength because of intrinsic limitations of soft materials. Here, we present a generic design principle that harnesses mechanical instability for a variety of spine-inspired fast and strong soft machines. Unlike most current soft robots that are designed as inherently and u...

Soft robots demonstrate great potential compared with traditional rigid robots owing to their inherently soft body structures. Although researchers have made tremendous progress in recent years, existing soft robots are in general plagued by a main issue: slow speeds and small forces. In this work, we aim to address this issue by actively designing...

Embedded and Controllable Shape Morphing with Twisted-and-Coiled Actuators

See the presentation video, https://youtu.be/tYhDeLtlHHU

Soft robots made from soft materials outper-form traditional rigid robots in safety, maneuverability, and adaptability. Various methods have been proposed to actu-ate soft robots such as cables, pneumatic, or smart materials (e.g., shape memory alloys, dielectric elastomer, or ionic polymer-metal composites, etc.). In this paper, we propose to leve...