Servo - October 2010

www.servomagazine.com/index.php?/magazine/article/october2010_GeerHead

GEERHEAD

During a recent semester, students in the Conducting Robots course constructed three robots. Chris Ault, associate professor of Interactive Multimedia; Dr. Teresa Nakra, associate professor of Music; Dr. Andrea Salgian, assistant professor of Computer Science; and Dr. Jennifer Wang, associate professor of Mechanical Engineering taught the class. Seventeen students took the course and made up three teams of roboticists.

Requirements included that the robots use both visualization and mechanical motion to communicate cues and instructions on tempo, dynamics, and articulation to the orchestra.

There has been little attempt by roboticists to date to create robots to conduct orchestras. A couple exceptions were Honda’s ASIMO robot conducting the Detroit Symphony in 2008, and Honda’s QRIO that conducted the Tokyo Philharmonic Orchestra for 90 seconds in March ‘04. However, the robot’s pre-coded activity did not include true interaction with the musicians in the orchestra.

The TCNJ students were provided with the input from MIDI files. This and visual analysis helped to give the robots more human-like gestures. The robots were able to convey more information than ASIMO.

ACRE Robot

The ACRE or Automated Conducting Robot Experience robot is a human size robot. The team built it with an upper frame and a lower frame to simulate the human torso and legs, respectively. The upper frame consists of three plates used to accommodate a laptop, a monitor (to simulate the conductor's face), and other necessary equipment. The arms were connected to the top plate, or shoulder plate. The team made the frame of aluminum 6061 for its strength, rigidity, and ease of use.

Since the robot's right arm keeps the tempo, its movement is on a fixed path that can be achieved with only three degrees of freedom: two in the shoulder joint and one in the elbow joint. There is a gripper at the end of the right arm for a hand.

The left arm has two degrees of freedom (more can be added) and is used to indicate cueing and volume control to the orchestra.

Each arm motor is a Hitec HSR-5990TG servo motor. The team selected this motor because it provided enough torque to enable the necessary arm capabilities given the arm’s weight and other factors. The gripper is a Lynxmotion Little Grip servo motor.

An Arduino Duemilanove was used for the arm’s motor controller. The team chose it for its open source platform which made it easy for team members to select and write code for the necessary functions. The Arduino was programmed in Processing — a programming language that is an extension of the Java language.

The lower body is a rectangular frame design with four

ACRE

At the recent performance of the TCNJ robot builds, the ACRE robot led a portion of music from West Side Story (written by Leonard Bernstein). The goal of this robotic project is to imbue the necessary traits of a human conductor so that it leads an orchestra through a given piece of music. The robot’s aesthetics bridge the gap between the human and robotic worlds, combining human and robotic features, according to the roboticists at TCNJ.

The robot proffers visible, physical cues from which the orchestra takes its lead. According to the students, this robot’s functions and communication modes include: - A right arm that conducts the beat pattern.