An autonomous self-reconfigurable modular robotic system with optimised docking connectors

Includes bibliographical references.Self-Reconfigurable Modular Robots are robotic systems consisting of a number of self-contained modules that can autonomously interconnect in different positions and orientations thereby varying the shape and size of the overall modular robot. This ground breaking capability is what in theory, makes self-reconfigurable modular robots more suitable for use in the navigation of unknown or unstructured environments. Here, they are required to reconfigure into different forms so as to optimise their navigation capabilities, a feat that is rendered impossible in conventional specialised robots that lack reconfiguration capabilities. However, the frequent development and use of self-reconfigurable modular robots in everyday robotic navigation applications is significantly hampered by the increased difficulty and overall cost of production of constituent robotic modules. One major contributor to this is the difficulty of designing suitably robust and reliable docking mechanisms between individual robotic modules. Such mechanisms are required to be mechanically stable involving a robust coupling mechanism, and to facilitate reliable inter-module power sharing and communication. This dissertation therefore proposes that the design and development of a functional low cost self-reconfigurable modular robot is indeed achievable by optimising and simplifying the design of a robust and reliable autonomous docking mechanism. In this study, we design and develop such a modular robot, whose constituent robotic modules are fitted with specialised docking connectors that utilise an optimised docking mechanism. This modular robot, its robotic modules and their connectors are then thoroughly tested for accuracy in mobility, electrical and structural stability, inter-module communication and power transfer, self-assembly, self-reconfiguration and self-healing, among others. The outcome of these testing procedures proved that it is indeed possible to optimise the docking mechanisms of self-reconfigurable modular robots, thereby enabling the modular robot to more easily exhibit efficient self-reconfiguration, self-assembly and self-healing behaviours. This study however showed that the type, shape, functionality and structure of electrical contacts used within the docking connectors for inter-module signal transfer and communication play a major role in enabling efficient self-assembly, self-reconfiguration and self-healing behaviours. Smooth spring loaded metallic electrical contacts incorporated into the docking connector design are recommended. This study also highlights the importance of closed loop control in the locomotion of constituent robotic modules, especially prior to docking. The open loop controlled locomotion optimisations used in this project were not as accurate as was initially expected, making self-assembly rather inaccurate and inconsistent. It is hoped that the outcomes of this research will serve to improve the docking mechanisms of self-reconfigurable modular robots thereby improving their functionality and pave the way for future large scale use of these robots in real world applications

Development of An In Vivo Robotic Camera for Dexterous Manipulation and Clear Imaging

Minimally invasive surgeriy (MIS) techniques are becoming more popular as replacements for traditional open surgeries. These methods benefit patients with lowering blood loss and post-operative pain, reducing recovery period and hospital stay time, decreasing surgical area scarring and cosmetic issues, and lessening the treatment costs, hence greater patient satisfaction would be earned. Manipulating surgical instruments from outside of abdomen and performing surgery needs precise hand-eye coordination which is provided by insertable cameras. The traditional MIS insertable cameras suffer from port complexity and reduced manipulation dexterity, which leads to defection in Hand-eye coordination and surgical flow. Fully insertable robotic camera systems emerged as a promising solution in MIS. Implementing robotic camera systems faces multiple challenges in fixation, manipulation, orientation control, tool-tissue interaction, in vivo illumination and clear imaging.In this dissertation a novel actuation and control mechanism is developed and validated for an insertable laparoscopic camera. This design uses permanent magnets and coils as force/torque generators in an external control unit to manipulate an in vivo camera capsule. The motorless design of this capsule reduces the, wight, size and power consumption of the driven unit. In order to guarantee the smooth motion of the camera inside the abdominal cavity, an interaction force control method was proposed and validated.Optimizing the system\u27s design, through minimizing the control unit size and power consumption and extending maneuverability of insertable camera, was achieved by a novel transformable design, which uses a single permanent magnet in the control unit. The camera robot uses a permanent magnet as fixation and translation unit, and two embedded motor for tilt motion actuation, as well as illumination actuation. Transformable design provides superior imaging quality through an optimized illumination unit and a cleaning module. The illumination module uses freeform optical lenses to control light beams from the LEDs to achieve optimized illumination over surgical zone. The cleaning module prevents lens contamination through a pump actuated debris prevention system, while mechanically wipes the lens in case of contamination. The performance of transformable design and its modules have been assessed experimentally

Realization and Lateral Stable Workspace Analysis of an Axially Symmetric Scalable Hexapod Robot

The maintenance and inspection of societal structures and equipment such as skyscrapers, bridges, and ship hulls are important to maintaining a safe lifestyle. Improper maintanance and delayed inspection can lead to catastrophic failure. In lieu of placing humans in potential harm, mobile robotic machining systems can be used to enable remote repair and maintenance within constrictive, hazardous, and inaccessible environments. Due to their intrinsic high mobility and 6-DOF control, hexapod walking robots are a salient solution to mobile machining. However, the static structure of traditional hexapod robots can be rather limiting when attempting to traverse over irregular terrain or manipulating objects. This research realizes a new scalable hexapod robot and analyzes the lateral stable workspace of the robot under different external loading conditions. The scalable design allows the robot to extend its legs which enhances the workspace and improves stability while manuevering through constrictive and irregular terrain. The design incorporates two additional prismatic joints into the legs of the traditional hexapod robot design providing a compact, rigid, and efficient design. The electronic printed circuit boards were designed and assembled in-house. A distributed control architecture was implemented to off-load low-level leg control to dedicated leg controllers. An analysis on the lateral stable workspace of the scalable hexapod robot under different external loading conditions is presented. A dynamic stable workspace criterion is derived. The stable workspace criterion provides a metric for comparing stable workspaces between hexapod robots with different configurations. Multiple simulations and physical experiments were conducted to demonstrate the advantages of a scalability in hexapod designs

NASA space station automation: AI-based technology review

Research and Development projects in automation for the Space Station are discussed. Artificial Intelligence (AI) based automation technologies are planned to enhance crew safety through reduced need for EVA, increase crew productivity through the reduction of routine operations, increase space station autonomy, and augment space station capability through the use of teleoperation and robotics. AI technology will also be developed for the servicing of satellites at the Space Station, system monitoring and diagnosis, space manufacturing, and the assembly of large space structures

A METHODOLOGY FOR AUTONOMOUS ROOF BOLT INSTALLATION USING INDUSTRIAL ROBOTICS

The mining sector is currently in the stage of adopting more automation, and with it, robotics. Autonomous bolting in underground environments remains a hot topic for the mining industry. Roof bolter operators are exposed to hazardous conditions due to their proximity to the unsupported roof, loose bolts, and heavy spinning mass. Prolonged exposure to the risk inevitably leads to accidents and injuries. The current thesis presents the development of a robotic assembly capable of carrying out the entire sequence of roof bolting operations in full and partial autonomous sensor-driven rock bolting operations to achieve a high-impact health and safety intervention for equipment operators. The automation of a complete cycle of drill steel positioning, drilling, bolt orientation and placement, resin placement, and bolt securing is discussed using an anthropomorphic robotic arm.A human-computer interface is developed to enable the interaction of the operators with the machines. Collision detection techniques will have to be implemented to minimize the impact after an unexpected collision has occurred. A robust failure-detection protocol is developed to check the vital parameters of robot operations continuously. This unique approach to automation of small materials handling is described with lessons learned. A user-centered GUI has been developed that allows for a human user to control and monitor the autonomous roof bolter. Preliminary tests have been conducted in a mock mine to evaluate the developed system\u27s performance. In addition, a number of different scenarios simulating typical missions that a roof bolter needs to undertake in an underground coal mine were tested

Skill-based reconfiguration of industrial mobile robots

Caused by a rising mass customisation and the high variety of equipment versions, the exibility of manufacturing systems in car productions has to be increased. In addition to a exible handling of production load changes or hardware breakdowns that are established research areas in literature, this thesis presents a skill-based recon guration mechanism for industrial mobile robots to enhance functional recon gurability. The proposed holonic multi-agent system is able to react to functional process changes while missing functionalities are created by self-organisation. Applied to a mobile commissioning system that is provided by AUDI AG, the suggested mechanism is validated in a real-world environment including the on-line veri cation of the recon gured robot functionality in a Validity Check. The present thesis includes an original contribution in three aspects: First, a recon - guration mechanism is presented that reacts in a self-organised way to functional process changes. The application layer of a hardware system converts a semantic description into functional requirements for a new robot skill. The result of this mechanism is the on-line integration of a new functionality into the running process. Second, the proposed system allows maintaining the productivity of the running process and exibly changing the robot hardware through provision of a hardware-abstraction layer. An encapsulated Recon guration Holon dynamically includes the actual con guration each time a recon guration is started. This allows reacting to changed environment settings. As the resulting agent that contains the new functionality, is identical in shape and behaviour to the existing skills, its integration into the running process is conducted without a considerable loss of productivity. Third, the suggested mechanism is composed of a novel agent design that allows implementing self-organisation during the encapsulated recon guration and dependability for standard process executions. The selective assignment of behaviour-based and cognitive agents is the basis for the exibility and e ectiveness of the proposed recon guration mechanism

Performance benefits of telerobotics and teleoperation - enhancements for an arm-based tank waste retrieval system

This report evaluates telerobotic and teleoperational arm-based retrieval systems that require advanced robotic controls. These systems will be deployed in waste retrieval activities in Hanford`s Single Shell Tanks (SSTs). The report assumes that arm-based, retrieval systems will combine a teleoperational arm and control system enhanced by a number of advanced and telerobotic controls. The report describes many possible enhancements, spanning the full range of the control spectrum with the potential for technical maturation. The enhancements considered present a variety of choices and factors including: the enhancements to be included in the actual control system, safety, detailed task analyses, human factors, cost-benefit ratios, and availability and maturity of technology. Because the actual system will be designed by an offsite vendor, the procurement specifications must have the flexibility to allow bidders to propose a broad range of ideas, yet build in enough restrictions to filter out infeasible and undesirable approaches. At the same time they must allow selection of a technically promising proposal. Based on a preliminary analysis of the waste retrieval task, and considering factors such as operator limitations and the current state of robotics technology, the authors recommend a set of enhancements that will (1) allow the system to complete its waste retrieval mission, and (2) enable future upgrades in response to changing mission needs and technological advances

Human factors in space telepresence

The problems of interfacing a human with a teleoperation system, for work in space are discussed. Much of the information presented here is the result of experience gained by the M.I.T. Space Systems Laboratory during the past two years of work on the ARAMIS (Automation, Robotics, and Machine Intelligence Systems) project. Many factors impact the design of the man-machine interface for a teleoperator. The effects of each are described in turn. An annotated bibliography gives the key references that were used. No conclusions are presented as a best design, since much depends on the particular application desired, and the relevant technology is swiftly changing

Control techniques for mechatronic assisted surgery

The treatment response for traumatic head injured patients can be improved by using an autonomous robotic system to perform basic, time-critical emergency neurosurgery, reducing costs and saving lives. In this thesis, a concept for a neurosurgical robotic system is proposed to perform three specific emergency neurosurgical procedures; they are the placement of an intracranial pressure monitor, external ventricular drainage, and the evacuation of chronic subdural haematoma. The control methods for this system are investigated following a curiosity led approach. Individual problems are interpreted in the widest sense and solutions posed that are general in nature. Three main contributions result from this approach: 1) a clinical evidence based review of surgical robotics and a methodology to assist in their evaluation, 2) a new controller for soft-grasping of objects, and 3) new propositions and theorems for chatter suppression sliding mode controllers. These contributions directly assist in the design of the control system of the neurosurgical robot and, more broadly, impact other areas outside the narrow con nes of the target application. A methodology for applied research in surgical robotics is proposed. The methodology sets out a hierarchy of criteria consisting of three tiers, with the most important being the bottom tier and the least being the top tier. It is argued that a robotic system must adhere to these criteria in order to achieve acceptability. Recent commercial systems are reviewed against these criteria, and are found to conform up to at least the bottom and intermediate tiers. However, the lack of conformity to the criteria in the top tier, combined with the inability to conclusively prove increased clinical benefit, particularly symptomatic benefit, is shown to be hampering the potential of surgical robotics in gaining wide establishment. A control scheme for soft-grasping objects is presented. Grasping a soft or fragile object requires the use of minimum contact force to prevent damage or deformation. Without precise knowledge of object parameters, real-time feedback control must be used to regulate the contact force and prevent slip. Moreover, the controller must be designed to have good performance characteristics to rapidly modulate the fingertip contact force in response to a slip event. A fuzzy sliding mode controller combined with a disturbance observer is proposed for contact force control and slip prevention. The robustness of the controller is evaluated through both simulation and experiment. The control scheme was found to be effective and robust to parameter uncertainty. When tested on a real system, however, chattering phenomena, well known to sliding mode research, was induced by the unmodelled suboptimal components of the system (filtering, backlash, and time delays). This reduced the controller performance. The problem of chattering and potential solutions are explored. Real systems using sliding mode controllers, such as the control scheme for soft-grasping, have a tendency to chatter at high frequencies. This is caused by the sliding mode controller interacting with un-modelled parasitic dynamics at the actuator-input and sensor-output of the plant. As a result, new chatter-suppression sliding mode controllers have been developed, which introduce new parameters into the system. However, the effect any particular choice of parameters has on system performance is unclear, and this can make tuning the parameters to meet a set of performance criteria di cult. In this thesis, common chatter-suppression sliding mode control strategies are surveyed and simple design and estimation methods are proposed. The estimation methods predict convergence, chattering amplitude, settling time, and maximum output bounds (overshoot) using harmonic linearizations and invariant ellipsoid sets

Automatic Romaine Heart Harvester

The Romaine Robotics Senior Design Team developed a romaine lettuce heart trimming system in partnership with a Salinas farm to address a growing labor shortage in the agricultural industry that is resulting in crops rotting in the field before they could be harvested. An automated trimmer can alleviate the most time consuming step in the cut-trim-bag harvesting process, increasing the yields of robotic cutters or the speed of existing laborer teams. Leveraging the Partner Farm’s existing trimmer architecture, which consists of a laborer loading lettuce into sprungloaded grippers that are rotated through vision and cutting systems by an indexer, the team redesigned geometry to improve the loading, gripping, and ejection stages of the system. Physical testing, hand calculations, and FEA were performed to understand acceptable grip strengths and cup design, and several wooden mockups were built to explore a new actuating linkage design for the indexer. The team manufactured, assembled, and performed verification testing on a full-size metal motorized prototype that can be incorporated with the Partner Farm’s existing cutting and vision systems. The prototype met all of the established requirements, and the farm has implemented the redesign onto their trimmer. Future work would include designing and implementing vision and cutting systems for the team’s metal prototype