This past week, on September 15 2016, Dalhousie University engineering students Devon Hartlen and Katherine Adye presented their team’s design for a sophisticated curling “smart broom” to the 2016 Engineers Nova Scotia Annual General Meeting in Halifax, by invitation after the students’ presentation at the CEEA annual student design competition. The project team included students Alex Landry and Emile Feniyanos, and was supervised by Dalhousie Civil Engineering professor John Newhook.
The students’ design improves on existing smart brooms, both commercial and prototypes, in a number of ways. These design improvements include:
- The broom’s design includes an interchangeable brush-head assembly, so that an athlete can exchange different brush heads of varying constructions. The smart broom is self-calibrating, so the interchange of brush pads does not impact the functionality or accuracy of the broom’s measurements.
- For convenience, the broom offers a rechargeable lithium-polymer battery. In addition, the broom includes voltage regulation circuitry required for measurement systems which are sensitive to changes in their input excitation, such as the strain gauges.
- The broom captures horizontal and vertical force, stroke rate, and stroke displacement (stroke length), which can aid in coaching. Force measurements are captured using strain gauges mounted on the brush handle (see picture at right). An accelerometer on the brush head assembly is used to capture stroke displacement.
- An inertial motion unit (IMU) mounted to the handle permits the brush to record the broom handle angle in 3-dimensional space in real time, another significant advance over existing technology.
- Data collection is performed through the use of an on-board Arduino-based “Teensy” 3.2 microcontroller. Data transmission uses a wireless transmitter to an off-broom computer for analysis.
A significant challenge with the prototype design was the placement of specific components so as to minimize the impact of an athlete during usage. To quote from the students’ final report:
The battery, Teensy, and additional circuitry, including bridge completion and amplification, voltage regulation, and wireless transmission, will all be mounted at the bottom of the brush in the zone where the mounting post is inserted into the handle. This keeps all components outside the grip zone of the athlete. Furthermore, by keeping all electronics components together it ensures that there will be no long wires running up the length of the handle. While this packaging will likely lead to added bulk at the base of the handle it should only add negligible weight. Furthermore, given the size of components that are being used the team is confident that all components will fit in this area.
Broom angle reporting in three dimensions offers a tremendous improvement over existing technologies, offering a coach the ability to correlate video analysis of an athlete to their broom handle movements, which is important because a steeper broom angle results in greater vertical force applied to the ice surface. Brush handle angle measurement was accomplished by using a six degree-of-freedom (DOF) inertial motion unit (IMU) composed of a three DOF gyroscope and a three DOF accelerometer allowing for the capture of the altitude and azimuth of the handle. In addition, strain gauges on the handle permit measurement of both vertical and horizontal force, another coaching key as horizontal force has only tangential impact on warming of the ice surface, which is the main factor in lowering the coefficient of friction of the ice to permit a stone to glide further and straighter down the sheet.
Our congratulations to Alex Landry, Devon Hartlen, Emile Feniyanos, and Katherine Adye and their supervisor, Dr. John Newhook, for advancing the state-of-the-art in the coaching of the sport.
For further information, interested readers may contact John Newhook at John.Newhook@Dal.ca.
