A prototype telerobotic platform for live transmission line maintenance: review of design and development.

This paper reports technical design of a novel experimental test facility, using haptic-enabled teleoperation of robotic manipulators, for live transmission line maintenance. The goal is to study and develop appropriate techniques in repair overhead power transmission lines by allowing linemen to wirelessly guide a remote manipulator, installed on a crane bucket, to execute dexterous maintenance tasks, such as twisting a tie wire around a cable. Challenges and solutions for developing such a system are outlined. The test facility consists of a PHANToM Desktop haptic device (master site), an industrial hydraulic manipulator (slave site) mounted atop a Stewart platform, and a wireless communication channel connecting the master and slave sites. The teleoperated system is tested under different force feedback schemes, while the base is excited and the communication channel is delayed and/or lossy to emulate realistic network behaviors. The force feedback schemes are: virtual fixture, augmentation force and augmented virtual fixture. Performance of each scheme is evaluated under three measures: task completion time, number of failed trials and displacement of the slave manipulator end-effector. The developed test rig has been shown to be successful in performing haptic-enabled teleoperation for live-line maintenance in a laboratory setting. The authors aim at establishing a benchmark test facility for objective evaluation of ideas and concepts in the teleoperation of live-line maintenance tasks

Design, Manufacturing and Control of an Advanced High-Precision Robotic System for Microsurgery

Microsurgeries like ophthalmic surgery confront many challenges like limited workspace and hand motion, steady hand movements, manipulating delicate thin tissues, and holding the instrument in place for a long time. New developments in robotically-assisted surgery can highly benefits this field and facilitate those complicated surgeries. Robotic eye surgery can save time, reduce surgical complications and inspire more delicate surgical procedures that cannot be done currently by surgeon’s hands. In this thesis work, the requirements for ophthalmic surgeries were studied and based on that a robotic system with 6 DOF is proposed and designed. This robotic system is capable of handling the position and orientation of the surgical instrument with theoretical accuracy of 10 μm. The design features a remote center of motion that defines the point of entry into the eye or patient’s body. The forward and inverse kinematics equations and workspace analysis of the robot is also discussed and presented. Six miniature DC motors with their PID controllers were installed on robot arms in order to run 6 DOF systems. Therefore, the dynamic behavior of a DC motor was studied and modeled and then the position and velocity transfer functions were derived and used to study the behavior of the system and also to manually tune the PID controller. The function of different elements of the control system including encoder, controller modules, Controller Area Network (CAN) and the controller software were discussed as well. The graphical user interface called EPOS Studio and performs as the motion controller is introduced and the way it organizes communications among the elements of the control system was described

Control of multiple tele-operated Robotic Bridge Transporters for remote handling of hazardous material

The objective of this research is to develop control of a multiple telerobot system based on Direct Numerical Processing Technology and propose a practically implementable collision avoidance algorithm for two gantry type robots sharing a common workspace; The tele-operatic set-up consists of two Robotic Bridge Transporters which are X-Y-Z positioning overhead bridge type cranes. These cranes consisting of three sub-assemblies for the X, Y and Z motions respectively are actuated by brushless servo drive motors. The DC motors are controlled by Modicon FA3240 automation controllers from a supervisory control station equipped with computer graphics based human-machine interface. Teleoperation is achieved through a programmable logic controller which acts as a command arbiter and data interface between the automation controllers and the supervisory control station computer; The collision avoidance algorithm proposes a collision free approach for a given path, by means of a minimum delay time technique for the two robots. Two examples, one each for a single segment and a two segment path for the two robots were tried out and found to work satisfactorily. The same can be extended to several segments as may be needed. The implementation methodology has been discussed

Development of Motion Control Systems for Hydraulically Actuated Cranes with Hanging Loads

Automation has been used in industrial processes for several decades to increase efficiency and safety. Tasks that are either dull, dangerous, or dirty can often be performed by machines in a reliable manner. This may provide a reduced risk to human life, and will typically give a lower economic cost. Industrial robots are a prime example of this, and have seen extensive use in the automotive industry and manufacturing plants. While these machines have been employed in a wide variety of industries, heavy duty lifting and handling equipment such as hydraulic cranes have typically been manually operated. This provides an opportunity to investigate and develop control systems to push lifting equipment towards the same level of automation found in the aforementioned industries. The use of winches and hanging loads on cranes give a set of challenges not typically found on robots, which requires careful consideration of both the safety aspect and precision of the pendulum-like motion. Another difference from industrial robots is the type of actuation systems used. While robots use electric motors, the cranes discussed in this thesis use hydraulic cylinders. As such, the dynamics of the machines and the control system designmay differ significantly. In addition, hydraulic cranes may experience significant deflection when lifting heavy loads, arising from both structural flexibility and the compressibility of the hydraulic fluid. The work presented in this thesis focuses on motion control of hydraulically actuated cranes. Motion control is an important topic when developing automation systems, as moving from one position to another is a common requirement for automated lifting operations. A novel path controller operating in actuator space is developed, which takes advantage of the load-independent flow control valves typically found on hydraulically actuated cranes. By operating in actuator space the motion of each cylinder is inherently minimized. To counteract the pendulum-like motion of the hanging payload, a novel anti-swing controller is developed and experimentally verified. The anti-swing controller is able to suppress the motion from the hanging load to increase safety and precision. To tackle the challenges associated with the flexibility of the crane, a deflection compensator is developed and experimentally verified. The deflection compensator is able to counteract both the static deflection due to gravity and dynamic de ection due to motion. Further, the topic of adaptive feedforward control of pressure compensated cylinders has been investigated. A novel adaptive differential controller has been developed and experimentally verified, which adapts to system uncertainties in both directions of motion. Finally, the use of electro-hydrostatic actuators for motion control of cranes has been investigated using numerical time domain simulations. A novel concept is proposed and investigated using simulations.publishedVersio