DOI QR코드

DOI QR Code

A Smart Bench Press Machine: Automatic Weight Control Sensitive to User Tiredness

  • Kim, Jihun (School of Mechanical and Control Engineering, Handong Global University) ;
  • Jo, Han-jin (School of Mechanical and Control Engineering, Handong Global University) ;
  • Kim, Kiyoung (School of Mechanical and Control Engineering, Handong Global University) ;
  • Ji, Hae-geun (School of Mechanical and Control Engineering, Handong Global University) ;
  • Kim, Jaehyo (School of Mechanical and Control Engineering, Handong Global University)
  • 투고 : 2018.12.06
  • 심사 : 2019.03.05
  • 발행 : 2019.03.31

초록

In order to provide a safe free-weight-training environment to people without workout trainers, we suggest a smart bench press machine with an automatic weight control system sensitive to user tiredness. Physical weight plates on the machine are replaced with a hydraulic cylinder as a press load and the cylinder knob is coupled with a step motor to change its tensile force automatically in-between lifting exercises. Three subjects participated to verify the usability of the smart bench press machine. They were asked to lift a 6-RM press load 10 times with 3 different lifting conditions: 1) no assistance, 2) a human assistance, and 3) the automatic weight control. All subjects were not able to complete the 10 sets without assistance due to tiredness, but they finished the full sets under the two assistive conditions. Average lifting speeds under the automatic weight control condition showed the most consistent level. Normalized quasi-tension data based on surface electromyogram signals of both Pectoralis Majors revealed that the subjects maintained the target muscle activation level above 50% but not more than 80% throughout the 10 sets. Therefore, the smart bench press machine is expected to both keep pace with the lifting exercise and reduce risk of injuries due to excessive muscle tensions.

키워드

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Figure 1. Modified bench press machine

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Figure 2. Automatic weight control algorithm of the smart bench press machine

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Figure 3. Exercise characteristics of a representative subject with different assistance conditions

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Figure 4. Lifting speed and quasi-tension with different assistance conditions

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