A2-piece six-axis force/torque sensor capable of measuring loads applied to tools of complex shapes

Abstract

Measuring forces and torques applied to tools of unconventional shapes can be challenging due to difficulties in connecting commercially available force/torque sensors. We propose an innovative, customizable six-axis force/torque sensor which can be clamped around a tool or end-effector to minimize the proximity between tool tip and sensor structure. The sensor is fabricated using 3d printing technology and consists of two pieces which together form an 8-legged Stewart platform. Each leg is designed as a cantilever beam to allow for a measurable displacement under an external load. The displacements of the legs are measured with 8 light intensity-based optoelectronic sensors, which exhibit high sensitivities and low noise levels without the need for external amplification circuitry. A customized printed circuit board and peripheral hardware are proposed to allow for efficient analog-to-digital conversion of the force/torque measurement. A calibration process is proposed which makes use of a commercial ATI Mini40 sensor and custom hardware to allow for fast calibration routines. Finally, the calibrated sensor design is compared to the ATI Mini40 sensor by measuring sequences of forces and torques, and the maximum errors of force/torque components (Fx,

A Contact Force Sensor Based on S-Shaped Beams and Optoelectronic Sensors for Flexible Manipulators for Minimally Invasive Surgery (MIS)

“…This conventional method requires high precision of the calibrating device and long duration of the calibration process to identify accurate and persistent relationships. We propose a simple and fast calibration method using a force/torque sensor, ATI Nano17, ATI Industrial Automation, Inc., USA [43].…”

Design of a Low-Cost Miniature Robot to Assist the COVID-19 Nasopharyngeal Swab Sampling

“…To guarantee a high linearity and sensitivity, the yellow area (measured distance in between 0 to 0.50 mm) in Figure 2 was used in this study. The selected sensor has been proved in our previous studies to be able to achieve large output voltage variations without using an amplifier and demonstrates low level of noises [9], [10]. The overall size of the swab gripper is 38(L) × 33(W) × 5(D) mm.…”

F-TOUCH Sensor: Concurrent Geometry Perception and Multi-Axis Force Measurement

“…However, in our case, there are two sensing modalities (force and tactile) presented in each image, hence we cannot use the exact same method as above. We obtain the numerical force-related numerical values from the image and, given the linearity of the sensor's spring mechanism structure, we apply a conventional force sensor calibration method [42] [33]. The rationale of the calibration process is to calculate the calibration matrix K, where the regression coefficients matrix is used to convert the output variables to force and moment loading data.…”

“…We set out to calibrate the six-axis force and torque component observations of the F-TOUCH sensor against a high-grade commercial six-axis force/torque sensor (ATI ® Mini40 F/T sensor) as a source of reference values [33]. As the sensing medium of the proposed sensor is made of silicone elastomera soft material, it is impossible to directly mount the ATI ® sensor atop the elastomer surface.…”