Remote robot manipulator coupled with remote-controlled guide vehicle for soil sampling in hazardous waste sites

The important initial step for remediation of hazardous waste is contaminant analysis since the cleanup operation can not begin until the contaminants in hazardous waste sites have been clearly identified. Ames Laboratory, one of the U.S. Department of Energy sites, has developed a robotic sampling system for automation of real-time contaminant analysis in situ which will provide the advantage of lowering the cost per sample, eliminating personnel exposure to hazardous environments, and allowing quicker results. Successful accomplishment of real-time contaminant analysis will require a remote manipulator to perform the sampling tasks in remote and unstructured surroundings, and a remote-controlled guide vehicle to move a remote manipulator into the desired sampling location;This thesis focuses on the design and construction of a remote-controlled guide vehicle to move the robotic sampling system into the contaminated field to obtain soil samples at the desired locations, the development of an integrated dynamic model of a remote manipulator, the identification of dynamic parameters in the integrated dynamic model, and the design of a mobile robotic sampling system. A four-wheeled vehicle prototype has been constructed and its performance tested manually in the field to verify the design requirements. To remotely control the vehicle, mechanical requirements to activate the brake, throttle, transmission, and steering linkages were determined based on experimental results. A teleoperated control utilizing hundred feet long umbilical cords was first employed to remotely control the vehicle. Next, the vehicle was modified to remotely operate in the field by radio control without the aid of long umbilical cords, satisfying all the design specifications;To reduce modeling error in the robotic system, the integrated dynamic system comprised of a remote manipulator (located on a trailer pulled by the remote-controlled guide vehicle) and its drive system has been modeled. The friction model as a function of velocity is included. The dynamic parameters such as velocity-dependent friction and gravity torque in the integrated dynamic model have been determined based on experimental results;Finally, a robotic arm, a sampling tool, and a soil recovery fixture for a mobile robotic sampling system to be mounted on the remote-controlled guide vehicle have been designed and analyzed. The integrated dynamic model for the robotic arm (mounted on the remote-controlled guide vehicle) and its drive system has also been developed

Master manipulator designed for highly articulated robotic instruments in single access surgery

The performance of a master-slave robotic system depends significantly on the ergonomics and the capability of its master device to correctly interface the user with the slave robot. Master manipulators generating commands in task space represent a commonly adopted solution for controlling a range of slave robots while retaining an ergonomic design. However, these devices present several drawbacks, such as requiring the use of clutching mechanics to compensate for the mismatch between slave and master workspaces, and the lack of capability to intuitively transmit important information such as specific joint limits to the user. In this paper, a novel joint-space master manipulator is presented. This manipulator emulates the kinematic structure of highly flexible surgical instruments which it is designed to control. This system uses 6 active degrees of freedom to compensate for its own weight, as well as to provide force feedback corresponding to the slave robot's joint limits. A force/torque sensor integrated at the end effector is used to relay user-generated forces and torques directly to specific joints. This is performed to counteract the friction stemming from structural constraints imposed by the kinematic design of the instruments. Finally, a usability study is carried out to test the validity of the system, proving that the instruments can be intuitively controlled even at the extremities of the workspace

Model-Based Robot Control and Multiprocessor Implementation

Model-based control of robot manipulators has been gaining momentum in recent years. Unfortunately there are very few experimental validations to accompany simulation results and as such majority of conclusions drawn lack the credibility associated with the real control implementation

Control strategies for robotic manipulators

This survey is aimed at presenting the major robust control strategies for rigid robot manipulators. The techniques discussed are feedback linearization/Computed torque control, Variable structure compensator, Passivity based approach and Disturbance observer based control. The first one is based on complete dynamic model of a robot. It results in simple linear control which offers guaranteed stability. Variable structure compensator uses a switching/relay action to overcome dynamic uncertainties and disturbances. Passivity based controller make use of passive structure of a robot. If passivity of a feedback system is proved, nonlinearities and uncertainties will not affect the stability. Disturbance observer based controllers estimate disturbances, which can be cancelled out to achieve a nominal model, for which a simple controller can then be designed. This paper, after explaining each control strategy in detail, finally compares these strategies for their pros and cons. Possible solutions to cope with the drawbacks have also been presented in tabular form. © 2012 IEEE

Calibration of UR10 robot controller through simple auto-tuning approach

This paper presents a calibration approach of a manipulator robot controller using an auto-tuning technique. Since the industry requires machines to run with increasing speed and precision, an optimal controller is too demanding. Even though the robots make use of an internal controller, usually, this controller does not fulfill the user specification with respect to their applications. Therefore, in order to overcome the user requirements, an auto-tuning method based on a single sine test is employed to obtain the optimal parameters of the proportional-integral-derivative PID controller. This approach has been tested, validated and implemented on a UR10 robot. The experimental results revealed that the performances of the robot increased when the designed controller, using the auto-tuning technique, was employed

Design and Development of a Computer Assisted Ground Control Technique for Space Station Robotics

Recent design activities for the International Space Station have included studies of the operations and productivity of the U.S. Laboratory module. A major finding was that the most 1 imi ted resource on the Station will be crew time. A ground-controlled robot has been proposed by Teledyne Brown Engineering that will help alleviate these constraints and allow around-the-clock U.S. Laboratory operations. However, the ground contra l of a mechanism in Earth orbit imposes command and feedback delays because of the distance and communicat i ans network involved. A unique predictive display for use by the ground operator in the presence of varying time delays has been developed and tested and has reduced the 11 move-and-wait 11 task times normally associated with delayed feedback teleoperations, minimized operator training, and reduced downlink bandwidth required

Robotic manipulators for single access surgery

This thesis explores the development of cooperative robotic manipulators for enhancing surgical precision and patient outcomes in single-access surgery and, specifically, Transanal Endoscopic Microsurgery (TEM). During these procedures, surgeons manipulate a heavy set of instruments via a mechanical clamp inserted in the patient’s body through a surgical port, resulting in imprecise movements, increased patient risks, and increased operating time. Therefore, an articulated robotic manipulator with passive joints is initially introduced, featuring built-in position and force sensors in each joint and electronic joint brakes for instant lock/release capability. The articulated manipulator concept is further improved with motorised joints, evolving into an active tool holder. The joints allow the incorporation of advanced robotic capabilities such as ultra-lightweight gravity compensation and hands-on kinematic reconfiguration, which can optimise the placement of the tool holder in the operating theatre. Due to the enhanced sensing capabilities, the application of the active robotic manipulator was further explored in conjunction with advanced image guidance approaches such as endomicroscopy. Recent advances in probe-based optical imaging such as confocal endomicroscopy is making inroads in clinical uses. However, the challenging manipulation of imaging probes hinders their practical adoption. Therefore, a combination of the fully cooperative robotic manipulator with a high-speed scanning endomicroscopy instrument is presented, simplifying the incorporation of optical biopsy techniques in routine surgical workflows. Finally, another embodiment of a cooperative robotic manipulator is presented as an input interface to control a highly-articulated robotic instrument for TEM. This master-slave interface alleviates the drawbacks of traditional master-slave devices, e.g., using clutching mechanics to compensate for the mismatch between slave and master workspaces, and the lack of intuitive manipulation feedback, e.g. joint limits, to the user. To address those drawbacks a joint-space robotic manipulator is proposed emulating the kinematic structure of the flexible robotic instrument under control.Open Acces

Modeling of Force and Motion Transmission in Tendon-Driven Surgical Robots

Tendon-based transmission is a common approach for transferring motion and forces in surgical robots. In spite of design simplicity and compactness that comes with the tendon drives, there exists a number of issues associated with the tendon-based transmission. In particular, the elasticity of the tendons and the frictional interaction between the tendon and the routing result in substantially nonlinear behavior. Also, in surgical applications, the distal joints of the robot and instruments cannot be sensorized in most cases due to technical limitations. Therefore, direct measurement of forces and use of feedback motion/force control for compensation of uncertainties in tendon-based motion and force transmission are not possible. However, force/motion estimation and control in tendon-based robots are important in view of the need for haptic feedback in robotic surgery and growing interest in automatizing common surgical tasks. One possible solution to the above-described problem is the development of mathematical models for tendon-based force and motion transmission that can be used for estimation and control purposes. This thesis provides analysis of force and motion transmission in tendon-pulley based surgical robots and addresses various aspects of the transmission modeling problem. Due to similarities between the quasi-static hysteretic behavior of a tendon-pulley based da Vinci® instrument and that of a typical tendon-sheath mechanism, a distributed friction approach for modeling the force transmission in the instrument is developed. The approach is extended to derive a formula for the apparent stiffness of the instrument. Consequently, a method is developed that uses the formula for apparent stiffness of the instrument to determine the stiffness distribution of the tissue palpated. The force transmission hysteresis is further investigated from a phenomenological point of view. It is shown that a classic Preisach hysteresis model can accurately describe the quasi-static input-output force transmission behavior of the da Vinci® instrument. Also, in order to describe the distributed friction effect in tendon-pulley mechanisms, the creep theory from belt mechanics is adopted for the robotic applications. As a result, a novel motion transmission model is suggested for tendon-pulley mechanisms. The developed model is of pseudo-kinematic type as it relates the output displacement to both the input displacement and the input force. The model is subsequently used for position control of the tip of the instrument. Furthermore, the proposed pseudo-kinematic model is extended to compensate for the coupled-hysteresis effect in a multi-DOF motion. A dynamic transmission model is also suggested that describes system’s response to high frequency inputs. Finally, the proposed motion transmission model was used for modeling of the backlash-like hysteresis in RAVEN II surgical robot