Robotics

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Resources

Lab

The Lab has 5 Windows workstations, 2 Linux workstations and 1 Mac machine. It is well equipped with a library of books and journals on robotics. It has separate offices for the graduate students, a conference room and a lunch room. Networking capabilities include connection to the University of Illinois network infrastructure. Other amenities include photocopier, printers, fridge, phone, etc. The lab also works in close collaboration with the Electronic Visualization Laboratory in the Department of Computer Science and Virtual Reality Laboratory in the Department of Mechanical and Industrial Engineering and has access to their resources too.

Puma

The Robotics Lab has two Unimation PUMA 560 Mark II manipulators which constitute the core of the control environment for various problems that we wish to solve. Though about twenty years old they are in good working conditions. The PUMA 560 resembles a human arm in its shape and capabilities. Each member is mechanically linked to the others and can rotate around an axis. The manipulator is endowed with six rotational degrees of freedom, which allow it to achieve complete dexterity within its workspace, that is to reach any point within the workspace with arbitrary orientation. To each motor shaft is coupled an incremental quadrature encoder, which is used to track the change in angular position of the motor shaft and allows to know the angular position of the corresponding link. The motors driving the major joints (1, 2 and 3) are equipped with electromagnetic brakes, which, once engaged, do not allow the shaft to rotate. The brakes are connected in parallel and can not be controlled individually. The brakes are released by continuously applying to them a sufficient voltage, which is experimentally set to 30 V. Conversely, they get engaged by removing such voltage. To control the brakes, solid-state relays are used, which is mounted inside the power supply cabinets. This setup fulfills the safety requirement, as the brakes are automatically engaged if the power supply is turned on , independently from the logic state of the input. We have removed from the manipulator bases the no-longer-used button which was provided to manually release the brakes in the original control environment.
Click here (AVI file, 12.0 MB) or here (MOV file, 11.0 MB) for the videos on PUMAs.

Controller

The task of the controller is to compute the motion of the system under control and to generate the corresponding control signals to be sent to the power amplifiers. The input to the controller can be either a program or a series of commands issued by the user. The controllers we selected for our system are Galil DMC-1860 Motion Controllers, which can simultaneously control the six axes of the PUMA 560 manipulators. The controllers are implemented as PCI cards and require a host PC to function. It is possible to interact with the controllers using either the DMC proprietary language from Galil or the most standard C/C++ and Visual Basic.

Amplifier

The Galil ICM/AMP-19x0 Interconnection/Amplifier Module collects in a single package both the terminals to interface the controllers to the external components and the power amplifiers to drive the external actuators. The maximum number of axes a Galil ICM/AMP-19x0 can handle is 4. Thus, two of them are needed for each manipulator, namely an ICM/AMP-1940 and an ICM/AMP-1920. To minimize the effect of noise, the metallic case of the modules has been grounded by connecting the ground pin on the input connector to the metal case of the respective (grounded) power supplies. The function of the interconnections section is to break the 100-pin cables from/to the motion controller into screw-type terminals, to which all the system components (encoders, switches, outputs, etc.) can be easily connected. Each controller is actually made of two boards: one is connected to the PCI bus of the host PC, while the other is just a daughter board which provides the extra space needed by the second input/output connector. The power supplies provide the (electrical) power which is modulated by the power amplifiers prior to being delivered to the motor actuators. Our power supplies have been maintained from the previous control environment. Ours simply consisted of adding the relay which controls the motor brakes and of mounting grids to prevent any contact with the cooling fans. Each power supply provides the constant voltages of 15, 30, 45 and 60 V. We only use the 30 V, as the input to the power amplifiers and to the relay. One of the two power supplies (M2004C) also has an additional board to provide low voltages for external logic and to accept external triggering signals. We do not use it and it is thus not necessary to turn it on at startup.

Force/torque sensor

A force/torque sensor measures the forces and torques applied to it by measuring the strain induced on strain gauges. A strain gauge is basically an extensible element whose strain can be measured by means of the its physical properties. The force/torque sensors in our system are ATI Industrial Automation Gamma F/T sensors. They are connected to digital-acquisition DAQ-PCI-6034E cards from National Instruments, which must be installed in the host PC; the provided power supply module must be connected between the sensors and the acquisition cards. The cables in the foreground go to the manipulator (motors and encoders) and to the force/torque sensor. The three cables go to the host PC, respectively to the controller (light color) and to the force/torque sensor acquisition card (black). The cables on the back of the power supply are used by the brakes control and to supply the power amplifiers. The motor, encoder and brake cables go to the connector at the base of the manipulator. The (black) cable going to the force/torque sensor was fit inside the manipulator structure.

PHANToM haptic device

PHANToM Premium 1.0A haptic device provides a range of motion approximating hand movement pivoting at the wrist. The device includes a passive stylus and thimble gimbal and provides 3 degrees of freedom positional sensing and 3 degrees of freedom force feedback. PHANToM haptic device connects to the PC via the parallel port (EPP) interface. Supported OS platforms include Windows 2000/XP/NT, RedHat Linux 7.2, RedHat Linux 9, RedHat Fedora, and SUSE 9.0.

Sensor agents

These are sensor mounted mobile robots that communicate through a distributed network. The idea is to use them for tasks such as explosives detection, locating hazardous chemical leaks and pollution sensing. Information collected from these agents can be processed with special algorithms and an accurate estimate of the location of a vapor-emitting source can be obtained. Having many mobile robots instead of one provides robustness to failures of a single agent or communication links.

SuperScout

The Nomad Super Scout II is an integrated mobile robot system with an onboard industrial PC, ultrasonic and tactile sensing modules and an optional vision system. This control system performs sensor and motor control, as well as communication. At a high level, the Nomad Super Scout II is controlled by a small, industrial PC which is mounted internally. The Nomad Super Scout II can be programmed using the Linux-based Nomadic Software Development Environment. This integrated package includes a graphic interface and a fully functional simulator. The Nomad Super Scout II is an ideal mobile system for research/education in Robotics and Artificial Intelligence. The high-level processor of this system is a Pentium 200 MHz industrial PC. The high-level processor communicates to the low-level processor through a serial port. The low-level processor of this system is a Motorola MC68332. Additionally, a TMS320C14 DSP is responsible for high-bandwidth motor control at 2 KHz control rates. The Nomad Super Scout II comes standard with odometric sensors, a tactile bumper ring, 16 Polaroid ultrasonic sonar sensors and optional vision system. The tactile system uses a ribbon switch enclosed in a energy absorbing neoprene channel. The effective range of ultrasonic sensors is from 15 cm to 650 cm. The optional Color PCI vision system comes with a color PCI framegrabber and color camera with 4 mm lens.
Click here (AVI file, 23.9 MB) for the video on Scout.

Aibo

AIBO is targeted for the tech-savvy robotic enthusiast as a Sony representive put it. Some of its great features include software giving it a 75-word vocubulary and advanced photo taking options. Its futuristic silver body is constructed with 16 degrees of freedom allowing smooth body movement. The various sensors that the AIBO has are infrared distance sensors, acceleration sensors, switches (head, face, legs, paws, tail), vibration sensors, temperature sensors. Some of the latest capabilities of the AIBO include:
1. Capturing digital images on voice commands. We have been able to navigate the environment using the LAN capability.
2. Saving images in JPEG format to the "Memory Stick".
3. Motion detection photography (AIBO Explorer AIBO-ware required).
4. Communication between AIBOs and owners.
It interacts with and responds to other AIBOs. This is what has led to RoboCup soccer games with AIBOs as players. It also expresses a wide variety of emotions (happiness, sadness, fear, dislike, surprise, anger) and instincts (play, search, hunger, sleep). It is also being used as a platform for testing various algorithms in the behavior based robotics project in the lab. It even comes with a wireless LAN capability.
Click here (AVI file, 29.1 MB) for the video on AIBO.

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