Over the last decade, a plethora of soft robotic devices have been proposed for the execution of complex grasping and dexterous manipulation tasks. Tasks requiring such increased dexterity are typically executed using fully-actuated, rigid end-effectors equipped with sophisticated sensing and controlled with complex control laws. The new class of soft robotic devices offers an alternative to the traditional end-effectors and facilitates the development of robotic grasping and manipulation solutions that are lightweight, safe to interact with, affordable, and easy to use and control. Within the class of soft robotic grippers and hands, promising recent developments were made in ultra-affordable, even disposable mechanisms based on origami and kirigami structures. This paper proposes a new kirigami-inspired robotic gripper geometry employing compression-based actuation. The compression actuation fundamentally differentiates this new design class from previous kirigami grippers, resulting in more compact robotic grippers with superior grasping capabilities. In particular, we investigate how the shapes of the internal cuts of the kirigami geometries can affect the gripper performance in terms of force exertion and grasping capabilities. A series of experiments are conducted to understand better the working principles behind this new type of kirigami grippers and experimentally validate their efficacy in the execution of complex, everyday life tasks. Further demonstrations of the gripper's capabilities include the pick-and-placing of human hair, egg yolk, and even liquids.

Soft robotic devices have been popular in handling intricate grasping and dexterous manipulation tasks, serving as an alternative to conventional, rigid end-effectors. These devices are relatively simple, lightweight, and cost-effective. Recently, kirigami based structures have been used to create low-cost and disposable soft robotic grippers and hands. These grippers undergo a complex post-contact reconfiguration and conform to an object's shape and size during grasping. In this paper, we explore this new class of soft robotic grippers by utilising them for single-grasp object classification and grasping force estimation. We install simplistic sensors on both the gripper and the actuation system to estimate the state of the kirigami gripper, and the collected data features are employed to train Random Forest models for identifying the grasped object. The classifier trained exhibits a high accuracy of 98 % in discriminating objects of various shapes. When handling food items, the classifier achieves an accuracy of 94 %, while in classifying transparent objects, the classifier obtained again a high accuracy of 97 %. Finally, object-specific force estimation models are triggered based on the classification decision of the Random Forest model to estimate the grasping force exerted by the gripper. These positive outcomes demonstrate the kirigami based robotic gripper's potential for object classification in a variety of circumstances, particularly where vision systems are not available or not reliable.

A popular solution for connecting different components in modern electronics, such as mobile phones, laptops, tablets, etc, is the use of flexible flat cables (FFC). Typically, it takes hours of repetition from a highly trained worker, or a high precision autonomous robot with specialised end effectors to reliably manage the installation of these cables. Human workers are prone to error, and cannot work endlessly without a break, while the robots often come with a significant expense, and require a substantial amount of time to program and reprogram. Additionally, the use of sophisticated sensing elements further increases the complexity of the required control system. As a result, the performance and robustness of such systems is far from sufficient, hindering their mass adoption. The manipulation of FFCs is also quite challenging. In this work, we focus on the robotic manipulation of a plethora of flexible cables, proposing a multi-modal gripper with locally-dexterous tips and active fingernails. The fingers of the gripper are equipped with: i) locally-dexterous fingertips that accommodate manipulation-capable degrees of freedom, ii) a combination of Nitinol-based active fingernails and suction cups that allow picking up and handling of cables that rest on flat surfaces, and iii) compliant finger-pads that conform to the object surface to increase grasping stability. The proposed robotic gripper is equipped with a camera and a perception system that allow for the execution of complex cable manipulation and assembly tasks in dynamic environments.

Grasping and manipulation are complex and demanding tasks, especially when executed in dynamic and unstructured environments. Typically, such tasks are executed by rigid articulated end-effectors, with a plethora of actuators that need sophisticated sensing and complex control laws to execute them efficiently. Soft robotics offers an alternative that allows for simplified execution of these demanding tasks, enabling the creation of robust, efficient, lightweight, and affordable solutions that are easy to control and operate. In this work, we introduce a new class of soft, kirigami-based robotic grippers, we study their post-contact behavior, and we investigate different cut patterns for their development. We follow an experimental approach in which several designs are proposed and employed in a series of grasping and force exertion tests to compare their capabilities and post-contact behavior. The results of such experiments indicate a clear relationship between degree of reconfiguration and grasping force, and provide key insights into the effect of the cut patterns in the performance of the designs. These findings are then used in the design process of an improved version of multi-layer, disposable kirigami grippers that are fabricated employing simple 3D printed layers and silicone rubber using the concept of Hybrid Deposition Manufacturing (HDM). A series of experimental results demonstrate that the proposed design and manufacturing methods can enable the creation of soft, kirigami-based grippers with superior grasping capabilities that can handle delicate, contaminated, and everyday life objects and can even be disposed off in an automated way (e.g., after handling hazardous materials, such as medical waste).

Flexible flat cables (FFC) are very popular for connecting different components in modern electronics (e.g., mobile phones, laptops, tablets, etc.). The manipulation of FFCs typically relies on highly trained workers that spend hours performing the same repetitive processes, or on autonomous robotic systems that are equipped with simple clamping mechanisms or pneumatically driven suction cups. Such robotic systems are difficult to program and reprogram and often rely on sophisticated sensing elements and complicated control laws. Moreover, the performance and robustness of such systems is far from sufficient, hindering their mass adoption. The manipulation of FFCs is also quite challenging. A good gripper should be able to pinch the cable steadily and execute insertion tasks of the cable connector with ease. The suction cup based solution is a good approach for holding the cable, but it makes the cable connector insertion very challenging as it can only apply limited shear forces. In this paper, we propose a locally-adaptive, pneumatic, parallel-jaw robot gripper equipped with fingertips that are able to both pinch the cable with a soft clamping mechanism and roll the cable surface on the soft fingertip structure until it reaches the desired connector. The gripper base accommodates a camera that allows for the recognition and pose estimation of the flat, flexible cables and other electronic components. The gripper is of low-cost and low-complexity and it can facilitate the efficient and robust execution of FFC grasping and assembly tasks.

Robot grasping and dexterous, in-hand manipulation allow robots to interact with their surroundings and execute a plethora of complex tasks such as pushing buttons, opening doors, and interacting with electrical appliances. In robotics, such complicated tasks are typically executed by multi-fingered end-effectors that are heavy, rigid, and expensive, employing numerous degrees of freedom and actuation. In this paper, we focus on the analysis, design, and development of a multi-grasp, reconfigurable, five fingered, anthropomorphic robot hand that can facilitate the execution of both robust grasping and dexterous manipulation tasks in service robotics and industrial automation applications. The robot hand is composed of eight actuators driving eighteen degrees of freedom with a telescoping mechanism and opposable thumb and pinky fingers to produce multiple anthropomorphic and non-anthropomorphic configurations for grasping and manipulation tasks. The reconfigurable finger base frames allow the hand to transform and utilize its degrees of actuation in an optimal manner to overcome its underactuated limitations. The underactuated robot hand is designed with a human hand structure that takes advantage of objects specifically designed for human operation (e.g., tool or handles with ergonomics for the human hand). This allows the system to better operate within a human-centered environment. The effectiveness of the proposed device is experimentally validated through three different tests: i) grasping experiments involving everyday-life objects, ii) force experiments that assess the force exertion capabilities of the hand in different finger base frame configurations, and iii) demonstration of in-hand object manipulation capabilities. The proposed hand weighs 1.28 kg and has a cost of approximately $1920 USD. The device is capable of exerting up to 14.3 N of contact force during pinch grasping and a maximum of 150.6 N power grasping.

Deep reinforcement learning (RL) algorithms have recently achieved remarkable successes in various sequential decision making tasks, leveraging advances in methods for training large deep networks. However, these methods usually require large amounts of training data, which is often a big problem for real-world applications. One natural question to ask is whether learning good representations for states and using larger networks helps in learning better policies. In this paper, we try to study if increasing input dimensionality helps improve performance and sample efficiency of model-free deep RL algorithms. To do so, we propose an online feature extractor network (OFENet) that uses neural nets to produce \emph{good} representations to be used as inputs to an off-policy RL algorithm. Even though the high dimensionality of input is usually thought to make learning of RL agents more difficult, we show that the RL agents in fact learn more efficiently with the high-dimensional representation than with the lower-dimensional state observations. We believe that stronger feature propagation together with larger networks allows RL agents to learn more complex functions of states and thus improves the sample efficiency. Through numerical experiments, we show that the proposed method achieves much higher sample efficiency and better performance. Codes for the proposed method are available at http://www.merl.com/research/license/OFENet

With the emergence of agile manufacturing in highly automated industrial environments, the demand for efficient robot adaptation to dynamic task requirements is increasing. For assembly tasks in particular, classic robot programming methods tend to be rather time intensive. Thus, effectively responding to rapid production changes requires faster and more intuitive robot teaching approaches. This work focuses on combining programming by demonstration with path optimization and local replanning methods to allow for fast and intuitive programming of assembly tasks that requires minimal user expertise. Two demonstration approaches have been developed and integrated in the framework, one that relies on human to robot motion mapping (teleoperation based approach) and a kinesthetic teaching method. The two approaches have been compared with the classic, pendant based teaching. The framework optimizes the demonstrated robot trajectories with respect to the detected obstacle space and the provided task specifications and goals. The framework has also been designed to employ a local replanning scheme that adjusts the optimized robot path based on online feedback from the camera-based perception system, ensuring collision-free navigation and the execution of critical assembly motions. The efficiency of the methods has been validated through a series of experiments involving the execution of assembly tasks. Extensive comparisons of the different demonstration methods have been performed and the approaches have been evaluated in terms of teaching time, ease of use, and path length.

In this paper, we propose a reinforcement learning-based algorithm for trajectory optimization for constrained dynamical systems. This problem is motivated by the fact that for most robotic systems, the dynamics may not always be known. Generating smooth, dynamically feasible trajectories could be difficult for such systems. Using sampling-based algorithms for motion planning may result in trajectories that are prone to undesirable control jumps. However, they can usually provide a good reference trajectory which a model-free reinforcement learning algorithm can then exploit by limiting the search domain and quickly finding a dynamically smooth trajectory. We use this idea to train a reinforcement learning agent to learn a dynamically smooth trajectory in a curriculum learning setting. Furthermore, for generalization, we parameterize the policies with goal locations, so that the agent can be trained for multiple goals simultaneously. We show result in both simulated environments as well as real experiments, for a 6-DoF manipulator arm operated in position-controlled mode to validate the proposed idea. We compare the proposed ideas against a PID controller which is used to track a designed trajectory in configuration space. Our experiments show that our RL agent trained with a reference path outperformed a model-free PID controller of the type commonly used on many robotic platforms for trajectory tracking.

In this paper, we propose a Petri Net decomposition approach for solving the bi-objective conflict-free routing for AGV systems. The objective is to minimize the deviation of delivery time and to minimize the total transportation time. The dispatching and conflict-free routing problem for AGVs is represented as an optimal firing sequence problem for Petri Net. A Petri Net decomposition approach is applied to solve the multi-objective optimization problem efficiently. The convergence of the algorithm is improved by reducing the search region. The effectiveness of the proposed method is compared with that of the conventional method. Computational results show the effectiveness of the proposed method.