This paper presents the design concept of an Instrumented Compliant Anatomical Palmar Mechanism (I-CAPM), which leverages the deformable curvatures of compliant beams to reconstruct the palm's displacement and force fields during grasping. The I-CAPM models the human palm using eight cantilever beams, with four beams converging at the thumb knuckle and the remainder individually connecting to the finger knuckles, emulating the human hand's oblique, transverse, and longitudinal arches. To enable independent analysis, each decoupled cantilever is embedded with a strain sensor array, allowing for field reconstruction on a single beam level. This architecture simplifies computational modeling and facilitates robust strain field reconstruction, deformation analysis, and real-time force perception. The methodology for characterizing the displacement and force fields of the beams is numerically illustrated and validated using commercial finite-element analysis (FEA). © 2025 IEEE.

This paper presents a design method based on distributed current source (DCS) that discretizes the permanent magnets (PMs) and electromagnets (EMs) into elemental current sources and derives the magnetic field and current-force models for design analyses of a 3-degree-of-freedom (3-DOF) planar motor with redundant inputs. The DCS models have been verified by comparing them with exact solutions and commercial finite element analysis (FEA). The results show that the DCS models are accurate (within 2.5% of exact solutions) and computationally efficient (a three-order improvement over FEA). As an illustration, the analytically derived DCS models are employed to analyze the geometrical constraints and parametric effects on the PM/EM layout and forces/torque performance of a 3-DOF planar motor. Using singular value decomposition, two designs are numerically evaluated. With the closed-form DCS models, the loci of the best/worst manipulability ellipsoids are graphically presented. © 2023 IEEE.

Motivated by the need to develop safe exoskeletons for collocated joint rehabilitation during the early stage of stroke recovery, this article presents a pantographic exoskeleton (PGE) capable of multi-degree-of-freedom motions in a single-joint collocated with the impaired joint. With minimum internal joint reactions in the presence of misalignment, the PGE "traces" the natural joint motion "like a pantograph" in the sagittal plane while performing in-bed rehabilitation, from which the joint parameters can be estimated for subsequent patient-specific motion training. An analytical model is presented to provide a rational basis for designing a collocated human-ankle/PGE mechanism, which has been numerically illustrated. The findings demonstrate that because the PGE joint do not restrict human ankle nature motion within the motion range of a typical ankle, it is less sensitive to joint misalignment as compared to conventional multijoint serial mechanisms that form a closed chain with the human limbs/joint. A prototype PGE has been designed; and its effectiveness for collocated ankle-joint manipulation has been experimentally investigated. Unlike conventional imaging methods that are prone to skin-marker errors and dependent on lumped-parameter approximations, the PGE directly measures the talus trajectory of the ankle-joint for characterizing its roll/slide motion and internal parameters.

Distributed force and displacement measurements are widely needed in many applications, particularly for monitoring impedance reaction during early rehabilitation following stroke recovery. Although the principles and instruments for precision measurements of displacements or forces are widely available, methods to design a human-specific sensing system that integrates force, displacement and impedance sensing for rehabilitation remain a challenge. To be effective, these human-specific sensing systems must be low cost, and can be rapidly designed, prototyped and fabricated within a few hours. Illustrated in the context of a stroke rehabilitation application, this paper presents a method to design, rapidly prototype and fabricate a reconfigurable magnetic sensing system to help monitor the asymmetrical kinematics and dynamics between the healthy and affected sides of a stroke patient. A prototype reconfigurable magnetic sensing system for monitoring the asymmetrical seat-reaction and foot plantar forces as well as for training hand-gripping has been designed, fabricated using recyclable rubbers, and experimentally evaluated. © 2020 IEEE.

Motivated by the need of pose estimation in a soft robot featured with continuous deformations, this paper proposes a field sensing method (FSM) where the compliant beam serves as a sensor to monitor the relative position between the front and rear axles of a mobile robot. Extending traditional designs of compliant mechanisms for flexible transmission, deformed configurations of the flexonic mobile node (FMN) can be retrieved in the three-dimensional space from nodal strain data along the compliant beam. The proposed FSM successfully applies the mode superposition to strain field sensing for nonlinear deformations, and it is numerically verified with finite element analysis. Error analysis will be carried out to quantify the precisions of position and orientation sensing and justify the application of FSM to pose estimation of the soft mobile robot. Fundamental theory of the proposed FSM and issues of its implementation in practice will be discussed. © 2020 IEEE.

Distributed force and displacement measurements are widely needed in many applications, particularly for monitoring impedance reaction during early rehabilitation following stroke recovery. Although the principles and instruments for precision measurements of displacements or forces are widely available, methods to design a human-specific sensing system that integrates force, displacement and impedance sensing for rehabilitation remain a challenge. To be effective, these human-specific sensing systems must be low cost, and can be rapidly designed, prototyped and fabricated within a few hours. Illustrated in the context of a stroke rehabilitation application, this paper presents a method to design, rapidly prototype and fabricate a reconfigurable magnetic sensing system to help monitor the asymmetrical kinematics and dynamics between the healthy and affected sides of a stroke patient. A prototype reconfigurable magnetic sensing system for monitoring the asymmetrical seat-reaction and foot plantar forces as well as for training hand-gripping has been designed, fabricated using recyclable rubbers, and experimentally evaluated. © 2020 IEEE.

Motivated by the need to develop safe exoskeletons for collocated joint rehabilitation during the early stage of stroke recovery, this article presents a pantographic exoskeleton (PGE) capable of multi-degree-of-freedom motions in a single-joint collocated with the impaired joint. With minimum internal joint reactions in the presence of misalignment, the PGE "traces" the natural joint motion "like a pantograph" in the sagittal plane while performing in-bed rehabilitation, from which the joint parameters can be estimated for subsequent patient-specific motion training. An analytical model is presented to provide a rational basis for designing a collocated human-ankle/PGE mechanism, which has been numerically illustrated. The findings demonstrate that because the PGE joint do not restrict human ankle nature motion within the motion range of a typical ankle, it is less sensitive to joint misalignment as compared to conventional multijoint serial mechanisms that form a closed chain with the human limbs/joint. A prototype PGE has been designed; and its effectiveness for collocated ankle-joint manipulation has been experimentally investigated. Unlike conventional imaging methods that are prone to skin-marker errors and dependent on lumped-parameter approximations, the PGE directly measures the talus trajectory of the ankle-joint for characterizing its roll/slide motion and internal parameters.

The loss of muscular strength and balancing disability make it difficult for stroke patients to move their body against gravity or to maintain balance. The asymmetrical kinematics and dynamics between the healthy and affected sides of stroke patients increase the risks of falls. This paper presents the development of a robotic-assisted Sit-to-Stand (RA-STS) mechanism to help stroke patients complete the STS movement essential for subsequent training and restore muscle functions. To provide a rational basis for the design/control of a RA-STS system, a relatively complete set of analytical models is presented for analyzing the asymmetric effects on the human joints during STS. Experiments were conducted to validate the concept feasibility and the kinematic and dynamic models by comparing simulations with experimentally measured results. Copyright © 2019 ASME

This paper presents a kinematic model and its inverse solutions to identify internal ankle parameters in sagittal plane from external motion data; the effects of initial guesses and noise on the solutions are discussed. Experiments were designed to eliminate skin-marker errors in motion data, and performed to validate the model and the estimation method experimentally by comparing estimations with measurements from the computed tomography scan of the ankle. Based on observations that the skin temperature of bony prominences is lower than that of muscle, a novel infrared (markerless) method to locate bony prominences as features is conceptualized; experiments suggest that this concept feasibility is promising.

This article develops a new human-machine perception interface method to convert visual patterns to accurate eddy-current stimulation using an electromagnet (EM) array. The eddy-current stimulation is formulated as a feedforward controller design. In this paper, a state-space model for the eddy-current stimulation is derived for design and analysis of the controller. Unlike traditional methods where the distributed parameter systems are often modeled using partial differential equations and solved numerically using numerical methods such as finite element analysis, the model presented here offers closed-form solutions in state-space representation. The novel approach enables the applications of the well-established control theory for analyzing the system controllability. The feasibility and accuracy of the feedforward control method are numerically illustrated and validated by generating the stimulation with two types of patterns, which provides an essential base for future research of human-machine perception interface. Copyright © 2018 ASME