The Basics
Patent Title: Force and/or motion measurement system having inertial compensation and measurement thereof
Patent Number: US8315823
Patent Filing Date: June 30, 2011
Patent Issue Date: November 20, 2012 (17 months to issue)
Inventors: Necip Berme and Hasan Cenk Guler
Assignee: Bertec Corporation
U.S. Classification: Force or Torque Measurement (702/41)
Claims: 18
Some Background on Force Measurement Systems
Biomedically, force sensors are used to continuously measure a force that is being exerted by the person on the platform. They measure forces in three dimensions and plot them against time [1]. Force plates are becoming increasingly more popular with sports researchers and coaches who are looking to use more advanced technology to help improve the performances of their athletes. An example of an athlete who may benefit from using a force measurement sensor is a swimmer who is looking to improve their starts and turns [3]. Sprinters also may use these inventions to work on pushing off a starting block.
The Bertec force measurement system [2], specifically, aims to relate the force or motion measured with inertial compensation. The force plate can take the form of a balance plate or jump plate, as well as gait using a treadmill-like apparatus. An important distinction of this device compared to other force plates is that it also assesses the motion of the athlete. The invention utilizes a motion acquisition system to look at the movement of a person running or walking on the treadmill.
What are the Main Claims?
The Bertec force measurement system [2] is made up of a force measurement assembly which includes a surface for the subject to stand on and one or more force transducers. This invention also includes a motion base, an inertial compensation system, and a means of data manipulation. The motion measurement system described in this patent also claims the same components and functions. There is a method for determining the forces or moments that are applied to the system which includes rotating the assembly with the subject in multiple dimensions, acquiring force and moment quantities using the transducer, and mathematically correcting the values.
Figure 1. Bertec force measurement system [2]
Figure 2. Bertec force and motion measurement system with treadmill and motion capture system [2]
How it Works
A key component of the device is the inertial compensation system [2], which uses linear or rotational profiles to calibrate the device and determine the inertial parameters. The motion base uses applied motion profiles to displace force and is especially good for supporting a treadmill system, as it can hold a large weight that undergoes motion. Below are the equations used to describe the force-inertia relationship.
The top equation illustrates the inertial forces and the bottom equation represents the moments. The kinematics of the force measurement assembly (aG and w) can be measured using accelerometers and gyroscopes respectively.
Compared to Other Devices
The main difference between Bertec’s device and devices that came before it is its ability to switch out the means of acquiring data. The force and motion measurement system is able to be used with a motion capture system and treadmill or with a force plate which allows for versatility in training measurements. This makes it simpler for coaches to view the force and motion values associated with their athletes’ performances and makes improvements off of the reported values.
References
[1] Leno, P. (2019, October 30). How to use force plates in sports. Retrieved from https://training-conditioning.com/news/how-to-use-force-plates-in-sports/
[2] Berme et al, Force and/or motion measurement system having inertial compensation and method thereof, US8315823, Bertec Corp, 2012
[3] Kistler. (2020). Biomechanics: faster, higher and stronger with performance analysis measuring technology. Retrieved from https://www.kistler.com/en/applications/sensor-technology/biomechanics-and-force-plate/sports-biomechanics/
