Novel Mechanically Fully Decoupled Six-Axis Force-Moment Sensor

Abstract

In this study, a novel six-axis force/moment (F/M) sensor was developed. The sensor has a novel ring structure comprising a cross-beam elastic body with sliding and rotating mechanisms to achieve complete decoupling. The unique sliding and rotating mechanisms can reduce cross-talk effects caused by minimized structural interconnection. The forces Fx, Fy, and Fz and moments Mx, My, and Mz can be measured for the six-axis F/M sensors according to the elastic deformation of strain gauges attached to the cross beam. Herein, we provide detailed descriptions of the mathematical models, model idealizations, model creation, and the mechanical decoupling principle. The paper also presents a theoretical analysis of the strain based on Timoshenko beam theory and the subsequent validation of the analysis results through a comparison of the results with those obtained from a numerical analysis conducted using finite element analysis simulations. The sensor was subjected to experimental testing to obtain the maximum cross-talk errors along the following six axes under different loadings (the errors are presented in parentheses): Fx under SMy (2.12%), Fy under SMx (1.88%), Fz under SMz (2.02%), Mx under SFz (1.15%), My under SFx (1.80%), and Mz under SFx (2.63%). The proposed sensor demonstrated a considerably improved cross-talk error performance compared with existing force sensors.

A Comprehensive Design of Six-Axis Force/Moment Sensor

“…Table 4 compares the numerical simulation results to the analytical solutions at 5 mm from the square platform. However, the current study’s result is preferable when compared to the 5.47% deviation found in some previous studies [ 14 , 20 ]. This is due to the fact that the Timoshenko equation is suitable for estimating the optimum design of the mechanically decoupled elastic cross-beam structure [ 21 ].…”

“…This was because of the changes only occurring on S FZ and S MZ . Meanwhile, this result outperforms, by less than 0.51%, the simulation results of studies by other researchers that have similar specifications and used the strain gage as a transducer [ 20 , 22 , 23 , 24 , 25 ]. When performing multiple loading on the structure, the strain gage arrangement could differentiate the loads into six-axis forces and moments.…”

“…The experimental test was similar to the data collection process for calibration. These procedures were similar to those described in the literature [ 20 , 22 ].…”

“…The strain gage arrangement used in this study is similar to the one used in [ 20 , 22 ], as shown in Figure 8 . The blue font signifies the visible strain gages, and the red font denotes the invisible strain gages (opposite side of the beam).…”

Development and Application of a Tandem Force Sensor

“…The cylinder-shaped ESB shown in Figure 5 b is the core of the traction force sensor, and it has layer A (black area), layer B (red area) and layer C (blue area). Compared with the diaphragm type ESB [ 29 ], cross beam type ESB [ 30 , 31 , 32 ], parallel type ESB [ 22 , 33 ], etc., the cylinder-shaped ESB is hollow, and the free space inside can be used as the connection channel between the contact force sensor and the traction force sensor. The layer A consists of A1 , A2 , A3 , and A4 , and layer C is composed by C1 , C2 , C3 , and C4 ( Figure 6 ) .…”