Development of a method for monitoring clubhead path and orientation through impact

Abstract

This study reports the development of a golf clubhead trajectory monitoring system which utilises PONTOS, a 3D motion analysis package from GOM. This paper demonstrates how this system can be used to monitor clubhead path and orientation and position throughout impact with future scope to simultaneously measure ball launch conditions. Six subjects performed 10 swings with a driver and a selection of these shots were analysed in detail. Face angle and dynamic loft were calculated as indicators of clubhead orientation and the effect of off-centre impacts on head rotation were quantified. When considering clubhead velocity, the flexibility of the system allowed velocities at different locations to be monitored. It was found that the velocity of the toe and heel differed by up to 5.7ms -1 at the moment of impact.

Comparative Analysis of Golf Clubhead Motion at Impact

“…After the impact, the clubface tends to open when the ball contacts the clubface in the toe region. The DL tends to decrease after the impact at the centre or low on the clubface, which is in accordance with other results based on the video monitoring system (Ellis, Roberts, & Sanghera, 2010).…”

How valid and accurate are measurements of golf impact parameters obtained using commercially available radar and stereoscopic optical launch monitors?

“…This trend may be a legacy of the development process as early versions of each launch monitor only reported ball parameters and clubhead measurement was introduced at a later data Weaker agreement was found when clubhead velocity measured by both launch monitors was compared to the GOM measurements; greater systematic bias and random variability was present in the data, particularly when considered relative to the ball velocity data. Immediately before impact, the clubhead is both translating and rotating and, as a result, velocity can vary by as much as 12.8 mph from heel to toe across a driver clubface [7]. Differences are, therefore, to be expected depending on where on the clubhead the velocity measurement is taken.…”

“…Instead, velocity of a point on the surface of the clubhead is measured and this may account for discrepancies in the data Clubhead orientation parameters can change rapidly leading up to impact due to clubhead rotations primarily about the shaft axis. The face angle of a driver closes at a rate of 2.9º/ms immediately prior to impact [7]. Therefore, the point in time at which the measurement is taken will significantly affect the output from the launch monitors.…”

“…The hardware con-sists of multiple high-speed video cameras, allowing dynamic events to be investigated at high frame rates and in three dimensions. Although developed for aeronautical and automotive industries, the potential of the system for tracking a driver clubhead has been demonstrated by Ellis et al [7]. This previous study did not include ball tracking and was limited by the definition of the clubface plane, which was defined by three markers on the face and, therefore, did not fully account for the curvature of a driver clubface.…”

The influence of club-head kinematics on early ball flight characteristics in the golf drive

“…Although it is reasonable that club-head velocity should indeed play a large part in generating ball velocity, it has also been suggested that the location of impact relative to the center of the clubface would also contribute to the ball velocity (Hocknell, 2002;Wiren, 1990). Quantitatively, researchers have established that the location of impact on the club-face has a large effect on club-head orientation, path, and velocity following impact (Ellis, Roberts, & Sanghera, 2010;Williams & Sih, 2002). However, there is currently a lack of understanding of the relative contribution of both club-head velocity and impact location on ball velocity.…”