Robotic Palm Research Articles

Programmable robotized ‘transfer-and-jet’ printing for large, 3D curved electronics on complex surfaces

Large, 3D curved electronics are a trend of the microelectronic industry due to their unique ability to conformally coexist with complex surfaces while retaining the electronic functions of 2D planar integrated circuit technologies. However, these curved electronics present great challenges to the fabrication processes. Here, we propose a reconfigurable, mask-free, conformal fabrication strategy with a robot-like system, called robotized ‘transfer-and-jet’ printing, to assemble diverse electronic devices on complex surfaces. This novel method is a ground-breaking advance with the unique capability to integrate rigid chips, flexible electronics, and conformal circuits on complex surfaces. Critically, each process, including transfer printing, inkjet printing, and plasma treating, are mask-free, digitalized, and programmable. The robotization techniques, including measurement, surface reconstruction and localization, and path programming, break through the fundamental constraints of 2D planar microfabrication in the context of geometric shape and size. The transfer printing begins with the laser lift-off of rigid chips or flexible electronics from donor substrates, which are then transferred onto a curved surface via a dexterous robotic palm. Then the robotic electrohydrodynamic printing directly writes submicrometer structures on the curved surface. Their permutation and combination allow versatile conformal microfabrication. Finally, robotized hybrid printing is utilized to successfully fabricate a conformal heater and antenna on a spherical surface and a flexible smart sensing skin on a winged model, where the curved circuit, flexible capacitive and piezoelectric sensor arrays, and rigid digital–analog conversion chips are assembled. Robotized hybrid printing is an innovative printing technology, enabling additive, noncontact and digital microfabrication for 3D curved electronics.

Soft Robotic Palm With Tunable Stiffness Using Dual-Layered Particle Jamming Mechanism

This article presents a novel robotic palm with a dual-layered structure designed to yield high surface conformity and controllable rigidity for enhanced grasping performance. It comprises a vacuum chamber for adjusting the stiffness of the palm via particle jamming and an air chamber for actively controlling the palm deformation. An auto-jamming control scheme that automatically solidifies the palm by sensing the internal pressure of the palm without any tactile sensors or visual feedback was also proposed. Given the design and control of the robotic palm, the performance of the dual-layered jamming mechanism was characterized in terms of shape adaptability and stiffness controllability. The contact surface areas increased by 180% compared with the single-layered robotic palm, and the adjustable stiffness was within a range of 0.20–2.53 N/mm for varying vacuum pressures. Moreover, the palm can act as a universal gripper for small objects, yielding a holding force of up to 13.9 N. The grasping performance of the palm in conjunction with robot fingers was evaluated for various objects for varying palm stiffness. The palm increases the grasping force by 2.0–3.1 times compared with flat skin. Multimodal grasping strategies for various objects were demonstrated by manipulating a robot arm.

Conformal Devices for Thermal Sensing and Heating in Biomedical and Human–Machine Interaction Applications

Thermal ablation has been adopted as one of the most common cancer treatment approaches in medical surgery. By increasing the temperature (>50 °C) on the cells, the cells are destroyed because of denaturation. Herein, an ultrathin Archimedean spiral pattern heater/sensor technology is introduced which can perform ablation by attaching conformally onto the organs for precise heating and temperature sensing. In the heater mode, the heater temperature is linearly proportional to the input joule heating power up to 400 mW. In the sensor mode, the temperature of the conformal metal wire is also linearly related to the resistance by the temperature coefficient of resistance (TCR). The conformal heater to perform ex vivo ablation on the porcine liver is utilized. By further integrating the devices with robotic palm and perform heat‐and‐sense interactions, a human–machine interface (HMI) apparatus is demonstrated which can be potentially applied in surgical robots or other tactile stimulation systems.

Exploring the role of palm concavity and adaptability in soft synergistic robotic hands

Robotic hand engineers usually focus on finger capabilities, often disregarding the palm contribution. Inspired by human anatomy, this paper explores the advantages of including a flexible concave palm into the design of a robotic hand actuated by soft synergies. We analyse how the inclusion of an articulated palm improves finger workspace and manipulability. We propose a mechanical design of a modular palm with two elastic rolling-contact palmar joints, that can be integrated on the Pisa/IIT SoftHand, without introducing additional motors. With this prototype, we evaluate experimentally the grasping capabilities of a robotic palm. We compare its performance to that of the same robotic hand with the palm fixed, and to that of a human hand. To assess the effective grasp quality achieved by the three systems, we measure the contact area using paint-transfer patterns in different grasping actions. Preliminary grasping experiments show a closer resemblance of the soft-palm robotic hand to the human hand. Results evidence a higher adaptive capability and a larger involvement of all fingers in grasping.

A novel versatile robotic palm inspired by human hand

Human palm plays a great role in object grasping and manipulation. However, most current robotic hand researches focused on finger designs, with very few efforts seen on robotic palm research. Here, we propose a novel robotic hand palm that is highly adaptive to object shape with variable stiffness and can be controlled actively. Our palm has one degree of freedom (DOF) mechanism and one particle sac that can be activated by vacuum. When the mechanism is actuated by a soft actuator, the particle sac is forced into contact with a target object, adapting to its shape. The particle sac can then be stiffened to freeze the current contact based on vacuum particle jamming. The stiffness is controlled by vacuum pressure. Embedded into a robotic hand, the proposed palm can coordinate its motion with the robotic fingers in grasping tasks. A more than three-fold holding force increase in pull-out experiments showed its superior functionality when compared with pure silicone rubber palm. Grasping of objects with different shapes and properties are also demonstrated. We believe that the proposed robotic palm design can provide new insight into more effective robotic hand design.

A 3D-printed Robot Hand with Three Linkage-driven Underactuated Fingers

In this study, we improved an underactuated finger mechanism by using Solidworks to simulate the grasp operation of a finger in some different situations. In addition, a robot palm is designed for the three-finger robot hand with the designed underactuated fingers. A Solidworks simulation was used to verify the rationality of the design. Some parts of the hand were modified to fit for 3D printing, and a prototype of the hand was produced by 3D printing, which could reduce the cost of the production process, as well as provide design flexibility and other advantages. Finally, some grasping experiments were made with the prototype. The results showed that the robot could grasp objects with different sizes, and further verified the rationality of the design and feasibility of fabricating the robot hand using 3D printing.

Fuzzy Model Based Stability Analysis of the Metamorphic Robotic Palm

The metamorphic hand can flexibly relocate fingers by a reconfigurable palm. A precondition for the successful hand operation would be a stable palm control system. Following this concern, this paper presents the stability analysis of the reconfigurable palm control system based on the Takagi-Sugeno (T-S) fuzzy model. The dynamic model of the metamorphic palm is developed by using the Euler Lagrangian theory and the closed-chain kinematic constraints. To further reduce the conservativeness in stability analysis and ensure a wider range of stable dynamic performance, a membership-dependent fuzzy modeling approach is also applied. Simulation is provided to demonstrate the achieved improvement of analysis results.

Real-Time Grasping Planning for Robotic Bin-Picking and Kitting Applications

Multi-fingered robotic hands can potentially offer a higher degree of dexterity for grasping a variety of parts than a traditional parallel gripper or a custom end of arm tool. However, real-time grasp planning for complex robotic hands is a challenging task. In this paper, we present real-time grasping planning algorithms that utilize two simple yet effective dimension reduction strategies. The first strategy is the “intersected volume” computation which places the robotic palm relative to the object as well as its environment. The second strategy is the “finger curling planes” which decomposes a grasp contact computation problem in high-dimensional configuration space into several independent grasp contact computation problems in low-dimensional configuration space. Our algorithms have been demonstrated with simulation, physical experiments, and robotic bin-picking and kitting applications on two robotic platforms with three different robotic hands.

Mathematical Analysis of Finger Positions of a Spherical Linkage Metamorphic Robot Palm

Grasping is the main function performed by the mechanical hand. Mechanisms with more functionality are needed for secure grasping of different and complex objects. With the advancement of the field of robotics it is important to think of mechanisms of multifingered robot hand with added functionality. The metamorphic mechanism with spherical linkage opens a wide opportunity to design a multi fingered robot hand with spherical palm, which can achieve human like dexterity. On the basis of an intensive study of literature, this paper focuses on the development of a geometrical model and mathematical analysis of spherical robot palm with fingers attached to it. To develop the generalised mathematical model, the co-ordinate transformation matrices of the joint axis position and the finger position have been derived. The transformation matrices have been derived with the position and orientation of the links and finger positions. So the co-ordinate points of a point of interest in the three dimensional space can be described at different configuration state of the mechanism. The detail analysis has been done through this mathematical and geometrical modelling of five-bar spherical metamorphic linkage robotic palm. This mathematical and geometrical model can be used to inspect the feasibility of the mechanism design for a multi fingered robot palm. Journal of Mechanical Engineering Vol.36 Dec. 2006 pp.18-26DOI = 10.3329/jme.v36i0.807