A shooting machine reproduces the arrow's behaviour with a human archer

The summary today

Partly, and how far depends on how it is built. The first comparison, in 1990, filmed a member of the Polish national team and a machine with the same bow at a thousand frames per second: the arrow's motion on the string showed no differences, but the judgement was only qualitative. In 2014 the measurement becomes precise and the picture splits: the arrow vibrates in flight at around 86 Hz whoever launches it, but the amplitude of the flex with a robot's mechanical fingers is 2.2 times that with archers and with a mechanical release less than a fifth, and the arrow's aerodynamic drag is more consistent when archers shoot it than when machines do. A year later the same group, reusing the 2014 measurements of the archer and the old mechanism as the benchmark, redesigns the robot's fingers: opening them to the minimum angle at which the string slides off, the flex drops to 6.94 mm against 6.86 for an international-level archer, at the same frequency, whereas the earlier mechanism gave 14.8. A later machine adds that the grip on the bow must also repeat identically on every shot, or precision drops. No comparison involves more than two archers, and drag, the one measurement in which the machine differed from the archer, has not been measured again with the new robot: that is why the status is "Contested".

Also phrased as: "the machine shoots like an archer"; "shooting robot versus archer"; "tuning with a shooting machine"; "a machine release is like a human one"

Evidence

• 1990
  For Equipment tests Published later

  Footage at 1,000 frames per second of the first phase of the shot, with the arrow released by a member of the Polish national team and by the mechanical release device: no qualitative difference in the arrow's motion between the two ways of shooting. No statistics, and the comparison concerns the arrow on the string, not in flight.

  Experimental and theoretical research in archery · Roman Pekalski

• 2014
  For Equipment tests Published later

  A/C/E recurve arrows, 72 shots filmed with two high-speed cameras and four launch methods (two top national archers, robot with mechanical fingers, robot with a release aid, compressed air): the arrow's flex frequency is around 86 Hz with every method that uses the bow, so the same mode of vibration is excited.

  J0520102 Aerodynamic properties of an archery arrow : Influence of flexural oscillation · Ryu Ando, Kyouhei Okawa, Takeshi Miyazaki, Hiroki Sugiura

• 2014
  Against Equipment tests Published later

  In the same experiment the amplitude of the flex varies widely with the launch method: 6.86 mm with archers, 2.2 times that with the robot's mechanical fingers and 0.18 times with the release aid. The drag coefficient is also more consistent when the archer shoots: its standard deviation grows with the release aid, with compressed air and, because of the excessive amplitude, with the mechanical fingers.

  J0520102 Aerodynamic properties of an archery arrow : Influence of flexural oscillation · Ryu Ando, Kyouhei Okawa, Takeshi Miyazaki, Hiroki Sugiura

• 2015
  For Equipment tests Published later

  A shooting robot with a competition recurve and redesigned mechanical fingers, compared with an international-level archer using the same bow and arrow: opening the fingers statically to the minimum angle at which the string slides off, the flex amplitude is 6.94 ± 0.23 mm against 6.86 ± 0.34 for the archer; with the fingers driven at different speeds it ranges from 7.07 to 7.44 mm. The frequency stays between 84 and 88 Hz for the robot and around 86.8 Hz for the archer. Conference proceedings, a single archer; the figures for the archer and the old mechanism are those already published in 2014.

  2A2-T08 Development of Archery Robot : Development of finger mechanism for controllable the bending vibration · Jun Wakatabe, Chisato Kanamori, Ryu Ando, Takeshi Miyazaki

• 2015
  Context Equipment tests Published later

  The same paper shows the other side: the finger mechanism of the robot's previous version gave the arrow a flex of 14.8 mm (standard deviation 0.39), more than twice the archer's. Once adjusted, the mechanical release is more repeatable than the human one, with a standard deviation of amplitude of 0.18-0.23 mm against 0.34.

  2A2-T08 Development of Archery Robot : Development of finger mechanism for controllable the bending vibration · Jun Wakatabe, Chisato Kanamori, Ryu Ando, Takeshi Miyazaki

• 2020
  Context Equipment tests Published later

  In developing a machine to select arrows, the first version left the bow free, so it came away on every shot and was gripped in a different position each time, with reduced precision; in the second, the grip holds the bow through a polyacetal element and springs forward on the shot as the archer's hand does.

  Development of an Archery Robot for the Selection of Arrows · Masashi Ohara, Naoki Kawasaki, Jun Nakahama, Yogo Takada, Hitoshi Watanabe

Status history

1. 1990 Reported The first direct comparison: a member of the Polish national team and a shooting machine, filmed at a thousand frames per second, and the arrow's motion on the string shows no qualitative differences between the two ways of shooting. It is a test on equipment, which for a question about equipment counts as direct evidence, but it is a single one and the judgement is by eye, without statistics: reported.
2. 2014 Contested The measurement becomes quantitative and the picture splits. Over 72 shots with four launch methods the arrow vibrates at around 86 Hz whoever launches it, but the amplitude of the flex with a robot's mechanical fingers is 2.2 times that with archers and with a mechanical release less than a fifth, and aerodynamic drag is more consistent when the archer shoots. One part of the behaviour is reproduced, another is not: contested.
3. 2015 Contested The same group redesigns the robot's fingers and closes the gap on flex: opening them to the minimum angle at which the string slides off, the flex drops to 6.94 mm against 6.86 for an international-level archer, at the same frequency, whereas the earlier mechanism gave 14.8. The archer's and the old mechanism's figures are those from 2014, so the two papers count as a single study. The difference in flex came from the mechanism, but drag, which was more consistent with archers, has not been measured again with the new fingers: the contrary result still stands, and the status stays contested.
4. 2020 Contested A machine built to select arrows adds a requirement: the grip on the bow must repeat identically on every shot, and the first version, which let the bow come away and caught it in a different place each time, lost precision. It confirms that the resemblance to an archer depends on how the machine is built, without any new comparison: the status stays contested.

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Research lines

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Other claims in this domain

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• CorroboratedAs it leaves the bow, the arrow flexes and snakes around the riser instead of leaving straight19 studies · 47 archers measuredStatus since 2012
• ReportedA camera-based scoring system misreads some arrows: the ones barely sticking out and the ones that shift the target face7 studies · 2 archers measuredStatus since 2017
• ReportedA chest band with fibre optic sensors measures breathing and mean heart rate with small errors, and an archer can wear it while shooting2 studiesStatus since 2019
• ReportedA compound bow stores between 70 and 100 joules and sheds about two thirds of the force at full draw4 studiesStatus since 2015

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