Fruit harvesting continuum manipulator inspired by elephant trunk

Over that last several years, research in the area of hyper-redundant robots and those robots based on tentacle/trunk type manipulators has become of great interest. Though much progress has been obtained in both the areas of robot construction and robot kinematics, there has been little progress in the implementation of a kinematic model for motion on a physical robot. We review both our 'elephant trunk' robot's construction and our previously designed kinematic model. We provide experimental results verifying not only the legitimacy of our kinematic model, but also the real time implementation of the model on the physical robot.

The four-legged bionic robot for agriculture has been one of the hotspots in the field of robotics. The farmland environment is complex, and the balance requirement of quadruped bionic robot is higher. However, head adjustment is a key factor affecting the balance of quadruped animals. Based on this, this study takes the four-legged animal goat as an example to investigate the effect of goat head movement adjustment on the balance of goat. In this study, the head and neck of goats were simplified to a two-link model. The kinematics model was established by D-H method. MATLAB software was used to solve it. Origin software was used to draw the movement track of the center of mass of the head. The center of mass movement of the head is a quarter ellipse. Then, the goat walking experiments were carried out on the different slopes (0°, 5°, 10°, 15°, 20°, 25°, 30°, 35° and 40°). MATLAB software was used to fit the movement data of goat head. The movement of the center of mass of the goat's head corresponds to Fourier 6. The result is: the determination coefficient is 0.8629, and the mean variance is 0.019. When the slope gradient gradually increases, the volatility gradually increases and is cyclical. The results of this study verify the rationality of the four-legged bionic mechanism under various parameters and reveal the mechanism of goat walking with an appendage at the head. Keywords: bionic four-legged robot, slope, head, center of mass, trajectory, balance DOI: 10.25165/j.ijabe.20191204.4287 Citation: Zhang F, Wang Y F, Teng S, Zheng L M, Wang J J, Chen Z J. Development of agricultural bionic four-legged robot: Effect of head movement adjustment on the stability of goats. Int J Agric & Biol Eng, 2019; 12(4): 10–15.

This thesis explores the fundamentals of a new class of parallel mechanisms called parallel mechanisms with configurable platforms as well as the design and analysis of parallel robots that are based on those mechanisms. Pure parallel robots are formed by two rigid links, the base and the end-effector, connected in parallel by independent serial chains, called legs. The novel concept behind parallel robots with configurable platforms is that the rigid end-effector is replaced by a closed-loop chain, the configurable platform. Some of the links of this closed-loop chain are attached to the legs so its configuration can be fully controlled from the actuators located on the base. The use of a closed-loop chain instead of a rigid end-effector allows the robot to interact with the environment using multiple contact points on the platform. This results in a robot that can combine motion and grasping capabilities into a structure that provides an inherent high structural stiffness. All the actuators are grounded on the base requiring no additional motor at the end-effector location to provide the grasping. High-speed pick-and-place robots and haptic interfaces are examples of devices that can benefit from this new type of architecture.

Objective To explore the application effects of elephant trunk sputum suction tube in stroke patients with non artificial airways. Methods A total of 80 stroke patients with non artificial airways in Department of Neurology were randomly divided into observation group (40 cases, elephant trunk type suction tube) and control group (40 cases, conventional type suction tube)according to the hospital order. The effectiveness of sputum suction and injury of airway mucous were compared between two groups. Results The one-time clean suctioning rate of sputum in observation group (94.05%) was higher than that in control group (61.52%). The damage ratio of airway mucous in observation group (3.57%) was lower than that in control group (20.38%). There were significant differences in effectiveness of sputum suction and injury of airway mucous between two groups (P<0.05). Conclusions Trunk type suction tube can improve sputum suction effects and reduce the incidence of airway mucous injury in stroke patients with non artificial airway. It is worthy of clinical application and promotion. Key words: Stroke; Non artificial airway; Sputum suction; Elephant trunk sputum suction tube

Agriculture and horticulture depend heavily on human labor to perform tasks that are often dirty, hazardous, and highly repetitive. One reason for the lack of automation of these tasks is the absence of suitable robotic handling equipment. Rigid robotic manipulators are typically incapable of performing dexterous manipulation tasks such as harvesting apples as they lack the ability to adapt to objects of various shapes and sizes. Such robotic manipulators need a large number of sensors and actuators to overcome these challenges, making them overly complex and not very robust. Therefore, the development of robotic manipulators for dexterous manipulation tasks has begun to focus on morphological computation, in which at least some aspects of the control are outsourced to the body of the robot. Taking inspiration from grasping mechanisms in natural systems, the field of soft robotics attempts to address this problem by constructing robots from soft materials. Although soft robotics may be the key to realizing automation of dexterous manipulation tasks, the current commercially available soft robotic grippers are only capable of performing simple pick-and-place tasks with open-loop control. This limited capability is in large part due to a lack of techniques to endow these manipulators with a sense of self-movement and body position, known as proprioception. Proprioception is a simple problem for conventional robots with rigid members and discrete joints, as the body position can be easily reconstructed using the information from encoders in the robots’ joints. However, it is a highly challenging problem for soft robots with virtually infinite degrees of freedom and above all, no suitable off-the-shelf sensors…

Currently available industrial robots are mainly of monolithic structure. Hence, the geometrical dimensions and the configuration of robotic arms are immutable. A modular design of serial manipulators allows to vary the structure of serial kinematic chains, for example, to adapt the system to a specific handling task. In this work we present the concept of a modular robot which has general kinematic structure by means of curved link elements. We show how to describe intuitively the assemblage of modular manipulators with curved links (referred to as Cuma-arms) by a parameter set. A Cuma-type arm and a dedicated path which can be followed by the end effector with 16 different postures is presented. For computation of the inverse kinematics of general serial 6R manipulators the algorithm of Husty and Pfurner is used and implemented on a real system.

An adaptive turning algorithm for a four-wheel robot tractor in the headland is presented in this paper. The navigation sensors consisted of an inertial measurement unit and a real-time kinematic global positioning system (GPS). An objective function based on weights was used to create the navigation path, connecting by continuous primitives. The asymmetric steering mechanism was then taken into consideration with a vehicle model. To follow the path accurately, the slide movement of the robot and the steering rate were taken into account by estimating the turning radius in real time. In addition, the vehicle model was tuned based on the results of each turn. Therefore, the turning control algorithm was optimized on the basis of the specific conditions in the field. Field experiments showed that the robot tractor approached the next path with an average lateral deviation of 3.9 cm at a speed of 1.2 m/s during a turn. Compared to a conventional turning scheme, the time consumption and turning trajectory were decreased by 17% and 21%, respectively. Keywords: autonomous tractor, path planning, dynamic circle-back turning, switch-back turning, robot tractor, reinforcement learning DOI: 10.25165/j.ijabe.20181106.3605 Citation: Wang H, Noguchi N. Adaptive turning control for an agricultural robot tractor. Int J Agric & Biol Eng, 2018; 11(6): 113–119.

Early outcomes of second-stage aortic repair after previous aortic arch surgery: the classical elephant trunk- vs. the frozen elephant trunk procedure

The human hand is an amazing tool, demonstrated by its incredible motor capability and remarkable sense of touch. To enable robots to work in a human-centric environment, it is desirable to endow robotic hands with human-like capabilities for grasping and object manipulation. However, due to its inherent complexity and inevitable model uncertainty, robotic grasping and manipulation remains a challenge. This thesis focuses on grasp adaptation in the face of model and sensing uncertainties: Given an object whose properties are not known with certainty (e.g., shape, weight and external perturbation), and a multifingered robotic hand, we aim at determining where to put the fingers and how the fingers should adaptively interact with the object using tactile sensing, in order to achieve either a stable grasp or a desired dynamic behaviour. A central idea in this thesis is the object-centric dynamics: namely, that we express all control constraints into an object-centric representation. This simplifies computa- tion and makes the control versatile to the type of hands. This is an essential feature that distinguishes our work from other robust grasping work in the literature, where generating a static stable grasp for a given hand is usually the primary goal. In this thesis, grasp adaptation is a dynamic process that flexibly adapts the grasp to fit some purpose from the objectâ s perspective, in the presence of a variety of uncertainties and/or perturbations. When building a grasp adaptation for a given situation, there are two key problems that must be addressed: 1) the problem of choosing an initial grasp that is suitable for future adaptation, and more importantly 2) the problem of design- ing an adaptation strategy that can react adequately to achieve desired behaviour of the grasped object. To address challenge 1 (planning a grasp under shape uncertainty), we propose an approach to parameterizing the uncertainty in object shape using Gaussian Processes (GPs) and incorporate it as a constraint into contact-level grasp planning. To realize the planned contacts using different hands interchangeably, we further develop a prob- abilistic model to predict the feasible hand configurations, including hand pose and finger joints, given the desired contact points only. The model is built using the con- cept of Virtual Frame(VF), and it is independent from the choice of hand frame and object frame. The performance of the proposed approach is validated on two differ- ent robotic hands, an industrial gripper (4 DOF Barrett hand) and a humanoid hand (16 DOF Allegro hand) to manipulate objects of daily use with complex geometry and various texture (a spray bottle, a tea caddy, a jug and a bunny toy). In the second part of this thesis, we propose an approach to the design of adapta- tion strategy to ensure grasp stability in the presence of physical uncertainties of objects(object weight, friction at contacts and external perturbation). Based on an object-level impedance controller, we first design a grasp stability estimator in the object frame using the grasp experience and tactile sensing. Once a grasp is predicted to be unstable during online execution, the grasp adaptation strategy is triggered to improve the grasp stability, by either changing the stiffness at finger level or relocating the position of one fingertip to a better area.

The Sri Lankan elephant can be classified as a generalist herbivore as it feeds on alarge number of plant species. Although, leaves and bark makeup bulk of theplant matter consumed by elephants, fruits are also eaten by elephants whenavailable. Therefore, they may be playa role in seed dispersal of such plantspecies. Aim of this investigation was to ascertain the role of elephants as a seeddispersal agent. This investigation was conducted from January 1998 to December 1999 in theNorth Western region of Sri Lanka. A total of 500 dung samples were collectedfrom different areas within the region. Dung boli were separated by hand andseeds present were identified by comparing with a reference seed collection. Thenumber of seeds present were also recorded. Part of the seeds were removed fromdung and their germination potential was determined while the remaining seedswere left in the dung. These dung piles were monitored and the number of seedsgerminated were recorded. Analysis of dung revealed 36 species of wild plants and 17 species of cultivatedplants. Of the Wild plants most commonly found plant species were Mimosapudica, Panicum maximum and Tamarindus indica. Among the cultivatedvarieties, Eleusine coracana, cucurbita maxima, Cucumis melo and Oryza sativawere commonest species observed. The seeds found in the dung boli germinatedwell after removal. However, when left in dung the germination potential wasvery low. This indicates that elephants do not playa key role in seed dispersal ofwild plants.

Bidirectional Human-Robot Learning: Imitation and Skill Improvement

When reaching to grasp, we coordinate how we preshape the hand with how we move it. The temporal and spatial coordination of transport and grasp components during reach-to-grasp behavior has been studied extensively in psychophysics experiments (M. Jeannerod 1984; Haggard and Wing 1995). Little is known, however, on the role of neocortex in generating, driving, or modulating the coordination of such behavior. The results discussed in this thesis attempt to answer the question: how do neural ensembles in the primary motor cortex functionally interact to produce coordinated behavior? In the first study, we examined the interactions between reach- and grasp-related neuronal ensembles while monkeys reached-to-grasp a variety of different objects in different locations. By describing the dynamics of these two ensembles as trajectories in a low-dimensional state space, we examined their coupling in time. The development of this coordination has been studied in infants and children (Claes von Hofsten 1984; Kuhtz-Buschbeck, Stolze, Johnk, et al. 1998; Wimmers et al. 1998). As children age, their inter-joint coordination becomes more stereotyped (Claes von Hofsten 1984; Kuhtz-Buschbeck, Stolze, Johnk, et al. 1998). Less is known about the role of motor cortex in developing coordinated reach-to-grasp. Additionally, studies have shown that after amputation, the cortical area previously involved in the control of the lost limb undergoes reorganization (J. N. Sanes et al. 1988; J. N. Sanes, Suner, and Donoghue 1990; Schieber and Deuel 1997; Wu and Kaas 1999; Qi, Stepniewska, and Kaas 2000), but limited work has gone towards developing BMIs that use neurons that are not tuned for kinetic or kinematic features. In the second study, we probed the emergence of coordinated reach-to-grasp in macaques that were being taught to cortically control a robotic arm through operant conditioning, and probed the neural correlates of this emergence.

In order to further reduce the incisions of laparoscopic surgery and the possibility of infection, the organic combination of single-incision laparoscopic surgery (SILS) and robotics has made the degree of minimally invasive surgery further improved. A new 5-DOF single-incision laparoscopic surgery robot was designed based on Axiomatic Design Theory, whose structure consisting of the movement mechanism, the endoscope and the position and pose adjustment mechanism. The robot parts are connected in series and parallel, allowing a pivotal motion of the endoscope in the center of the robot for realizing the incision. In order to achieve a performance optimization and a dynamic control of the single-incision laparoscopic surgical robot, the kinematics and dynamic modeling and dynamic stiffness analysis of the robot are especially important. The forward kinematics equation, inverse kinematics equation and Jacobian matrix of the SILS robot are derived based on D-H method and geometric method, and the kinematics numerical simulation is carried out by Matlab. The dynamic equation of the robot is derived by Kane method. Subsequently, a numerical simulation of the robot dynamics equation is performed, with its virtual prototype utilized to set the motion plan of the robot mechanism. After robot’s dynamic simulation, the numerical changes of the driving force and torque for each robot’s moving mechanism are obtained. The performed simulation results further verify the correctness of the established robot’s dynamic model. Finally, utilizing the above methods, the dynamic stiffness model and evaluation index of the robot are determined, and the dynamic stiffness of the robot is analyzed and evaluated. The results of the kinematics, dynamic and stiffness analysis of the SILS robot further validate that the 5-DOF SILS robot has a reasonable structure, motion and sufficient stability to meet the needs of single-incision laparoscopic surgery.

Aerial manipulators can manipulate objects while flying, allowing them to perform tasks in dangerous or inaccessible areas. Advanced aerial manipulation systems are often based on rigid-link mechanisms, but the balance between dexterity and payload capacity limits their broader application. Combining unmanned aerial vehicles with continuum manipulators emerges as a solution to this trade-off, but these systems face challenges with large actuation systems and unstable control. To address these challenges, we propose Aerial Elephant Trunk, an aerial continuum manipulator inspired by the elephant trunk, featuring a small-scale quadrotor and a dexterous, compliant tendon-driven continuum arm for versatile operation in both indoor and outdoor settings. We develop state estimation for the quadrotor using an Extended Kalman Filter, shape estimation for the continuum arm based on piecewise constant curvature, and whole-body motion planning using minimum jerk principles. Through comprehensive fundamental verifications, we demonstrate that our system can adapt to various constrained environments, such as navigating through narrow holes, tubes, or crevices, and can handle a range of objects, including slender, deformable, irregular, or heavy items. Our system can potentially be deployed in challenging conditions, such as pipeline maintenance or electricity line inspection at high altitudes.

The area of trunk/tentacle-type biological manipulation is not new, but there has been little progress in the development and application of a physical device to simulate these types of manipulation. Our research in this area is based on using an 'elephant trunk' robot. In this paper, we review the construction of the robot and how it compares to biological manipulators. We apply our previously designed kinematic model to describe the kinematics of the robot. We finish by providing some examples of motion planning and intelligent manipulation using the robot.