The McGill Schönflies-Motion Generator (McGill SMG) is a parallel robot capable of a special class of motions, those produced with serial robots termed SCARA (Selective-Compliance Assembly Robot Arm): three independent translations and one rotation about an axis of fixed direction. Such motions form a subgroup of the displacement group of rigid-body motions, termed the Schönflies subgroup.
• Pick and place operations
• Medical manipulators
• Educational platforms
• Pharmaceutical setups
A Collaborative Research and Development Project (with Concordia
University and Bombardier Inc.)
• In this project, 2 redundant, 7-axis robots, REDIESTRO-1 & REDIESTRO-2, were designed to specifically address the problem of achieving reliable force control. The project involves the development of software and hardware required to use the two robots together in a dual-arm configuration.
• A significant effort was invested in enhancing our Robot Visualization System, that is used as a telemanipulation simulator.
To service and maintain aircraft and space structures
In error-tolerant tasks:
In accuracy-demanding tasks:
Purposes of the prototype:
To demonstrate accurate positioning of the tool carried by the orientation submodule in the presence of vibrations of the base due to the flexibility of the gross manipulator.
Main Components of the System:
• Proximal Module (Gross Manipulator),
• Distal Module (Fine Manipulator):
-Positioning Submodule (Cuatro Arm).
-Orientation Submodule (Agile Wrist).
• Two motors are mounted onto the platform
• Unlimited steering capability
• No wire entanglement problems
• Uniform tire-wear rate
• Two identical motors are used for driving
• especially suitable for indexing mechanisms;
• can handle planar, spherical, and spatial mechanisms;
• high quality rendering.
BEAVER: a CAD/CAE software package for the modelling of involute bevel gears. Features:
allows for on-line parameter changes;
• produces a database in a format readily transformable into G-code;
• based on the exact spherical involutes;
• high quality rendering.
SIXPAQ: a CAD/CAE software package for the interactive synthesis
of six-bar dwell linkages. Features:
• any six-bar dwell planar linkage can be designed by simply choosing a reduced number of parameters;
• input-output plots and animation are available.
Gear transmissions entail drawbacks in robotics applications:
• backlash introduces unmodelled dynamics
• dry friction is unavoidable
• a gear is as strong as the weakest of its teeth
Harmonic drives solve above problems at the expense of:
• unacceptable high flexibility
• hysteretic effects that mar the dynamics of robots
• limited applicability: only coaxial shafts can be coupled
Conventional transmissions are unsuitable for mechatronic applications.
An alternative solution:
speed reducer intended to replace gears and harmonic drives.
United States Patent, No. US 6,382,0382
• Low friction
• Low backlash
• High stiffness
• Manufacturable with general-purpose CNC machine tools
• Planar, to couple parallel shafts
• Spherical, to couple intersecting shafts
• Convex planar, for higher machinability
Example of applications:
• Robotic actuators
• Mechatronic systems