Soft robots can create complicated structures and functions for rehabilitation. The posture perception of soft actuators is critical for performing closed-loop control for a precise location. It is essential to have a sensor with both soft and flexible characteristics that does not affect the movement of a soft actuator. This paper presents a novel end-to-end posture perception method that employs flexible sensors with kirigami-inspired structures and long short-term memory (LSTM) neural networks. The sensors were developed with conductive sponge materials. With one-step calibration from the sensor output, the posture of the soft actuator could be calculated by the LSTM network. The method was validated by attaching the developed sensors to a soft fiber-reinforced bending actuator. The results showed the accuracy of posture prediction of sponge sensors with three kirigami-inspired structures ranged from 0.91 to 0.97 in terms of $R^2$. The sponge sensors only generated a resistive torque value of 0.96 mNm at the maximum bending position when attached to a soft actuator, which would minimize the effect on actuator movement. The kirigami-inspired flexible sponge sensor could in future enhance soft robotic development.

This letter presents a pneumatic artificial muscle-based elbow exosuit designed for driving and assisting the elbow joint. By combining the bionic attachment method inspired by the brachioradialis muscle and the pennation architecture of the artificial muscle, the elbow exosuit achieves high output torque while maintaining a slim profile of only 10 mm thickness. To guide the design process, the letter utilizes the force balance condition of infinitesimal parts of the artificial muscle fiber and the virtual work principle to calculate the path change of the muscle wrapped around the arm surface. This approach helps determine key parameters and obtain the theoretical assisting torque. To validate the model, a test bench is constructed to measure the relationship between assisting torque and flexion angle, demonstrating the accuracy of the theoretical calculations. Furthermore, a bionic elbow joint is built to verify the driving ability of the exosuit. Preliminary human feasibility test is conducted, and users report no discomfort. The results indicate a 37.5% decrease in muscle effort in the bicep brachii when lifting a 4 kg weight and a 30.5% decrease during the holding task. A stroke survivor successfully bends the arm and raises his hand to the mouth while wearing the exosuit. These findings demonstrate the feasibility in driving and providing assistance to the user and significant potential for assisting individuals in their daily lives.

Artificial muscles have been in development for decades and play a crucial role in the field of wearable robotics. However, a universal device for both sensing and regulating forces in artificial muscles is still absent, rendering scenario-required force control unfeasible. Inspired by Golgi tendon organs, this work proposes bionic ExoTendon for force sensing and regulating in artificial muscles as a general solution. Leveraging the principles of triboelectrification and electrostatic induction, the ExoTendon offers high linearity, minimal hysteresis, and adjustable sensitivity and range, making it suitable as the tendon of artificial muscles. Specifically, the ExoTendon effectively enable adjustment to the pretension of the artificial muscles, yielding various assistive forces under the same input. With the optimized pretension level and closed-loop force control, the artificial muscle–based exosuit achieves self–force regulation, substantially improving walking balance and speed in stroke subjects under low input, demonstrating its promise in wearable robotics and rehabilitation medicine.

Soft artificial muscles have been used for wearable robots and unstructured environments as they are inherently compliant and flexible. However, this soft characteristic also leads to the challenge of feedback on contraction length and force. This study proposes an embedded proprioceptive displacement and force sensing method for tube-fiber pneumatic artificial muscle. In these actuators, the generated movement and force are due to the defamation of the tubes. The proposed sensing methods filled the tube with magnetic material, to convert the deformation of the tube into changes in the magnetic field. These changes in the magnetic field are detected by Hall sensors. Experimental results show that the output of the Hall sensor exhibits a monotonic relationship with the actual displacement and force changes, demonstrating high repeatability and low hysteresis. These findings are consistent with the behavior expected from the mathematical model. Data-driven models were built for displacement and force estimation. The accuracy was 2.87% root-mean-square error (RMSE) in measuring displacement and 4.56% RMSE in measuring force. In addition, the practical application of the sensing method is demonstrated by a human-subject test, showcasing its ability to estimate displacement and force in dynamic and practical scenarios. The integration of compact sensors within artificial muscles renders this sensing technique a promising solution for addressing the challenges of force and displacement sensing in soft artificial muscles. It offers a solution for artificial muscles and holds promise for future advancements in this field.

Chronic lower-extremity wounds in patients undergoing exoskeleton-assisted rehabilitation require materials that can both protect tissue and enable real-time physiological monitoring. Conventional dressings lack dynamic sensing capability, while current conductive hydrogels often compromise either adhesion or electronic performance. Here, we present a biointegrated hydrogel (CPSD) composed of carboxymethyl chitosan (CMCS) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) forming the conductive backbone, integrated with dopamine-functionalized sodium alginate (SD); the network is assembled via electrostatic complexation and carbodiimide (EDC/NHS)-mediated covalent crosslinking. The resulting hydrogel exhibits a dense, tissue-conformal porous network with tunable swelling, stable mechanical integrity, and high photothermal conversion efficiency. In vitro assays confirmed potent antioxidant activity, strong antibacterial performance (>90% under near-infrared), and excellent cytocompatibility and hemocompatibility. CPSD shows bulk conductivity ~1.6 S·m⁻¹, compressive modulus ~15 kPa, lap-shear adhesion on porcine skin ~9.5 kPa, and WVTR ~75 g·m⁻²·h⁻¹, supporting stable biointerfaces for motion/sEMG sensing. Integrated into a lower-limb exoskeleton, CPSD hydrogels adhered securely during motion and reliably captured electromyographic and strain signals, enabling movement-intent detection. These results highlight CPSD hydrogel as a multifunctional interface material for next-generation closed-loop rehabilitation systems and mobile health monitoring.

This paper presents the design and evaluation of a lightweight, minimally actuated lower limb exoskeleton that emphasizes hip–knee coordination for natural and efficient gait assistance. The system adopts a hip-only motorized actuation strategy in combination with an electromagnetically controlled knee locking mechanism, ensuring rigid stability during stance while providing compliant assistance during swing. To support sit-to-stand transitions, a gas spring–ratchet mechanism is integrated, which remains disengaged in the seated position, delivers assistive torque during rising, and provides cushioning during the descent to enhance safety and comfort. The control framework fuses foot pressure and thigh-mounted IMU signals for finite state machine (FSM)-based gait phase detection and employs a fuzzy PID controller to achieve adaptive hip torque regulation with coordinated hip–knee control. Preliminary human-subject experiments demonstrate that the proposed design enhances lower-limb coordination, reduces muscle activation, and improves gait smoothness. By integrating a minimal-actuation architecture, a practical sit-to-stand assist module, and an intelligent control strategy, this exoskeleton strikes an effective balance between mechanical simplicity, functional support, and gait naturalness, offering a promising solution for everyday mobility assistance in elderly or mobility-impaired users.