arXiv subjects

Jeffrey I. Lipton

Publications and source records attributed to Jeffrey I. Lipton.

6 recordsLinked to original sources

arXiv2026

Electrostatic Clutch-Based Mechanical Multiplexer with Increased Force Capability

As robotic systems become increasingly articulated, conventional actuation still dedicates one motor to each degree of freedom (DoF). Mechanical multiplexers address this limitation by allowing a single motor to control multiple outputs through clutches, reducing the number of required motors. However, previous multiplexers have relied on bulky mechanical clutch designs, limiting their development. This study presents an electrostatic capstan clutch-based transmission architecture that enables high-force mechanical multiplexing with independent, simultaneous, and fully actuated control of multiple outputs from a single motor. Our transmission implements four fully-actuated linear outputs, achieving individual output forces of up to 212 N and output speeds of up to 69.5 mm/s. We demonstrate our transmission on a commercial tendon-driven hand, where sequentially allocating system-wide torque capacity to individual outputs increased vertical grip strength by 4.09x and raised horizontal carrying capacity to 111.2 N, the highest reported among five-fingered tendon-driven robotic hands. These results demonstrate that electrostatic clutch-based mechanical multiplexing enables high-force, independent, simultaneous, and fully actuated control while overcoming the limitations of previous mechanical multiplexers.

cs.RO↗

arXiv2025

ProForm: Solder-Free Circuit Assembly Using Thermoforming

Electronic waste (e-waste) is a growing global challenge, with millions of functional components discarded due to the difficulty of repair and reuse. Traditional circuit assembly relies on soldering, which creates semi-permanent bonds that limit component recovery and contribute to unnecessary waste. We introduce ProForm, a thermoforming approach for solder-free circuit prototyping. By encapsulating electronic components with pressure-formed thermoplastics, ProForm enables secure, reversible mounting without the need for solder or custom mechanical housings. This approach supports a wide range of substrates, including flexible, paper-based, and non-planar circuits, facilitating easy reuse, replacement, and rapid prototyping. We demonstrate ProForm's versatility to support prototyping practices. We show that ProFormed circuits exhibit good electrical performance and mechanical stability. While motivated by a need for sustainable electronics practices, ProForm has other significant advantages over traditional soldering.

cs.HC↗

arXiv2025

Design and Reprogrammability of Zero Modes in 2D Materials from a Single Element

Mechanical extremal materials, a class of metamaterials that exist at the bounds of elastic theory, possess the extraordinary capability to engineer any desired elastic behavior by harnessing mechanical zero modes -- deformation modes that demand minimal or, ideally, no elastic energy. However, the potential for arbitrary construction and reprogramming of metamaterials remains largely unrealized, primarily due to significant challenges in qualitatively transforming zero modes within the confines of existing metamaterial design frameworks. This work presents a method for explicitly defining and in situ reprogramming zero modes of two-dimensional extremal materials by employing straight-line mechanisms (SLMs) and planar symmetry, which prescribe and coordinate the zero modes, respectively. We validate the concept experimentally on square-symmetric lattices and corroborate its generality for hexagonal lattices through finite-element analysis, together spanning the full theoretical gamut of extremal behaviors. The method is used to design, test, and reprogram centimeter-scale isotropic, orthotropic, and chiral extremal materials by reorienting the SLMs in place, enabling these materials to smoothly and reversibly interpolate between extremal modalities (e.g., unimode to bimode), material properties (e.g., negative to positive Poisson's ratios), and selectively enable chirality without changing the metamaterial's global structure. This methodology provides a straightforward and explicit strategy for the design and tuning of all varieties of two-dimensional extremal materials, enabling dynamic mechanical metamaterial construction to completely cover the gamut of elastic properties.

physics.app-ph↗

arXiv2025

Torque Responsive Metamaterials Enable High Payload Soft Robot Arms

Soft robots have struggled to support large forces and moments while also supporting their own weight against gravity. This limits their ability to reach certain configurations necessary for tasks such as inspection and pushing objects up. We have overcome this limitation by creating an electrically driven metamaterial soft arm using handed shearing auxetics (HSA) and bendable extendable torque resistant (BETR) shafts. These use the large force and torque capacity of HSAs and the nestable torque transmission of BETRs to create a strong soft arm. We found that the HSA arm was able to push 2.3 kg vertically and lift more than 600 g when positioned horizontally, supporting 0.33 Nm of torque at the base. The arm is able to move between waypoints while carrying the large payload and demonstrates consistent movement with path variance below 5 mm. The HSA arm's ability to perform active grasping with HSA grippers was also demonstrated, requiring 20 N of pull force to dislodge the object. Finally, we test the arm in a pipe inspection task. The arm is able to locate all the defects while sliding against the inner surface of the pipe, demonstrating its compliance.

cs.RO↗

arXiv2024

Torsion Resistant Strain Limiting Layers Enable High Grip Strength of Electrically-Driven Handed Shearing Auxetic Grippers

Soft grippers have demonstrated a strong ability to successfully pick and manipulate many objects. A key limitation to their wider adoption is their inability to grasp larger payloads due to objects slipping out of grasps. We have overcome this limitation by introducing a torsionally rigid strain limiting layer (TR-SLL). This reduces out-of-plane bending while maintaining the gripper's softness and in-plane flexibility. We characterize the design space of the strain limiting layer and Handed Shearing Auxetic (HSA) actuators for a soft gripper using simulation and experiment. The inclusion of the TR-SLL with HSAs enables HSA grippers to be made with a single digit. We found that the use of our TR-SLL HSA gripper enabled pinch grasping of payloads over 1 kg. We demonstrate a lifting capacity of 5 kg when loading using the TR-SLL. We also demonstrate a peak pinch grasp force of 5.8 N, and a peak planar caging force of 14.5 N. Finally, we test the TR-SLL gripper on a suite of 43 YCB objects. We show success on 37 objects demonstrating significant capabilities.

cs.RO↗

arXiv2024

Johnsen-Rahbek Capstan Clutch: A High Torque Electrostatic Clutch

In many robotic systems, the holding state consumes power, limits operating time, and increases operating costs. Electrostatic clutches have the potential to improve robotic performance by generating holding torques with low power consumption. A key limitation of electrostatic clutches has been their low specific shear stresses which restrict generated holding torque, limiting many applications. Here we show how combining the Johnsen-Rahbek (JR) effect with the exponential tension scaling capstan effect can produce clutches with the highest specific shear stress in the literature. Our system generated 31.3 N/cm^2 sheer stress and a total holding torque of 7.1 Nm while consuming only 2.5 mW/cm^2 at 500 V. We demonstrate a theoretical model of an electrostatic adhesive capstan clutch and demonstrate how large angle (theta > 2pi) designs increase efficiency over planar or small angle (theta < pi) clutch designs. We also report the first unfilled polymeric material, polybenzimidazole (PBI), to exhibit the JR-effect.

cs.RO↗