Study of the dynamic interaction with the environment and loading of the human body is important in ergonomics, sports and rehabilititation. This paper presents a method to estimate power transfer between the human body and the environment during short interactions and relatively arbitrary movements using a combination of inertial and force sensing

Kortier, H.G.

Schepers, H.M.

Veltink, P.H.

English

University of Twente Research Information

 IEEE Benelux EMBS Symposium  December 6-7, 2007 SENSING DYNAMIC INTERACTION WITH THE ENVIRONMENT P.H. Veltink, H.G. Kortier, H.M. Schepers University of Twente, Institute for BioMedical Technology (BMTI), Enschede, the Netherlands   1 Introduction Study of the dynamic interaction with the environment and loading of the human body is important in ergonomics, sports and rehabilitation.  This paper presents a method to estimate power transfer between the human body and the environment during short interactions and relatively arbitrary movements using a combination of inertial and force sensing. 2 Methods Power transfer between two bodies is given by: ωrrrr⋅+⋅= MvFP  (1) Performed work follows by integrating power over time. Angular velocity ωr can be measured using rate gyroscopes, velocity vr can be estimated from accelerometers after rotation to the inertial coordinate system, subtraction of gravitational acceleration, integration and applying adequate start and end conditions. Force Frand moment Mrcan be sensed by a 6 DOF force/moment sensor system [1] (Figure 1).  Figure 1. Experimental setup of a handle connected to a mass load, with 3D inertial and force/moment sensors. 3 Results An example result is shown in figure 2. The mass is transferred from the ground to a 75 cm high table, accounting for a potential energy change of 69 J. The estimated performed work in this case is 70 J. 4 Discussion The presented method also allows partial characterization of the dynamic characteristics of unknown loads. 0 0.2 0.4 0.6 0.8 0 0.10.200.10.20.30.40.50.60.70.80.9y(m)x(m)z(m) 0 0.5 1 1.5 2 2.5 3 3.5-505Powerrot (W)0 0.5 1 1.5 2 2.5 3 3.5-2000200Powertrans (W)0 0.5 1 1.5 2 2.5 3 3.5-2000200Powertot (W)0 0.5 1 1.5 2 2.5 3 3.5-1000100Time (s)Work (J) Figure 2. Example measurement showing the feasibility of the PowerSensor concept: Upper: reconstructed position and force directions; Lower: Estimated power transfer and work done. Acknowledgement This study was financially supported by the Dutch Ministry of Economic Affairs under the FreeMotion project. Patent application has been filed. References [1] H.M. Schepers, B.F.J.M. Koopman, P.H. Veltink, Ambulatory Assessment of Ankle and Foot Dynamics, IEEE Trans. Biomedical Engineering, vol. 54, 2007, pp. 895-902. 

Sensing dynamic interaction with the environment

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Study of the dynamic interaction with the environment and loading of the human body is important in ergonomics, sports and rehabilitation. This paper presents a method to estimate powe

P. H. Veltink

H. G. Kortier

H. M. Schepers

CiteSeerX

Study of the dynamic interaction with the environment and loading of the human body is important in ergonomics, sports and rehabilitation. This paper presents a method to estimate power transfer between the human body and the environment during short interactions and relatively arbitrary movements using a combination of inertial and force sensing

0 0.2 0.4 0.6 0.8 0 0.10.200.10.20.30.40.50.60.70.80.9y(m)x(m)z(m)Figure 1. Experimental setup of a handle connected to a mass load, with 3D inertial and force/moment sensors SENSING DYNAMIC INTERACTION WITH THE ENVIRONMENT Veltink, PH, Kortier, HG, Schepers HM University of Twente, Institute for BioMedical Technology (BMTI), Enschede, the Netherlands INTRODUCTION   Study of the dynamic interaction with the environment and loading of the human body is important in ergonomics, sports and rehabilitation. This paper presents a method to estimate power transfer between the human body and the environment during short interactions and relatively arbitrary movements using a combination of inertial and force sensing.  METHODS  Power transfer between two bodies is given by: ωrrrr⋅+⋅= MvFP      (1) Performed work follows by integrating power over time. Angular velocity ωr can be measured using rate gyroscopes, velocity vr can be estimated from accelerometers after rotation to the inertial coordinate system, subtraction of gravitational acceleration, integration and applying adequate start and end conditions. Force Frand moment Mrcan be sensed by a 6 DOF force/moment sensor system [1] (Figure 1)          RESULTS  An example result is shown in figure 2. The mass is transferred from the ground to a 75 cm high table, accounting for a potential energy change of 69 J. The estimated performed work in this case is 70 J.  DISCUSSION   The presented method also allows partial characterization of the dynamic characteristics of unknown loads  ACKNOWLEDGEMENT   This study was financially supported by the Dutch Ministry of Economic Affairs (FreeMotion project).  REFERENCES  [1] Schepers HM, Koopman BFJM, Veltink PH, Ambulatory Assessment of Ankle and Foot Dynamics, IEEE Trans. Biomedical Engineering, 2007, 54: 895-902.  0 0.5 1 1.5 2 2.5 3 3.5-505Powerrot (W)0 0.5 1 1.5 2 2.5 3 3.5-2000200Powertrans (W)0 0.5 1 1.5 2 2.5 3 3.5-2000200Powertot (W)0 0.5 1 1.5 2 2.5 3 3.5-1000100Time (s)Work (J)Figure 2. Example measurement: Left: reconstructed position and force directions; Right: Estimated power transfer and work done 

Ambulatory Assessment of Ankle and Foot Dynamics,

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Sensing dynamic interaction with the environment

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