Strain Gauge Force Sensor Research Articles

Retraction note on: An accurate method to directly measure water strider’s stroke force on the water (Aquarius paludum: Heteroptera: Gerridae)

We measured the force of free pulling water striders, using a hair attached to their backs and a 3D strain gauge force sensor. We showed the repeatability and accuracy of this method. The error of the method was estimated by comparing the projected angles of the force vector on each plane derived from the force data, with those angles derived from video recordings, and was estimated as 12.4%. Females on average were stronger (1.32 mN) than males (0.87 mN), however the ratio of force/weight was not significantly different. Compared with other lighter species, A. paludum seems to be stronger, but the force/weight ratio is actually lower as expected. A. paludum applies about 0.30–0.40 mN/cm with its mid-legs, thus avoiding penetrating the surface tension while propelling itself rapidly over the water.

SU-8 force sensing pillar arrays for biological measurements.

The generation and sensation of mechanical force plays a role in many dynamic biological processes, including touch sensation. This paper presents a two-axis micro strain gauge force sensor constructed from multiple layers of SU-8 and metal on quartz substrates. The sensor was designed to meet requirements for measuring tactile sensitivity and interaction forces exerted during locomotion by small organisms such as the nematode Caenorhabditis elegans. The device is transparent and compatible with light microscopes, allowing behavioral experiments to be combined with quantitative force measurements. For the first time, we have characterized the scale of interaction forces generated in wild-type C. elegans in probing and responding to their environment during locomotion. The device features sub-microN force resolution from 1 Hz to 1 kHz, >25 microN range, kHz acquisition rates and biocompatibility.

RETRACTED ARTICLE: An accurate method to directly measure water strider’s stroke force on the water (Aquarius paludum: Heteroptera: Gerridae)

Abstract We measured the force of free pulling water striders, using a hair attached to their backs and a 3D strain gauge force sensor. We showed the repeatability and accuracy of this method. The error of the method was estimated by comparing the projected angles of the force vector on each plane derived from the force data, with those angles derived from video recordings, and was estimated as 12.4%. Females on average were stronger (1.32 mN) than males (0.87 mN), however the ratio of force/weight was not significantly different. Compared with other lighter species, A. paludum seems to be stronger, but the force/weight ratio is actually lower as expected. A. paludum applies about 0.30–0.40 mN/cm with its mid-legs, thus avoiding penetrating the surface tension while propelling itself rapidly over the water.

Friction-Based <i>In Situ </i>Endpoint Detection of Copper CMP Process

Chemical mechanical polishing (CMP) has been extensively used in the integrate circuit (IC) manufacturing industry as a widely accepted global planarization technology, accurate in situ endpoint detection of CMP process can reduce the product variance, significantly improve yield and throughput. A CMP in situ endpoint detection system, which measured the friction and downforce during CMP process using a specially designed three-axis strain gauge force sensor, was developed. The frictional transition from copper (Cu) to tantalum (Ta) barrier as well as Ta barrier to silicon dioxide (SiO2) dielectric was detected during CMP process. The experimental results showed that the change of friction could be detected when the polished material changed. The developed CMP in situ endpoint detection system is feasible for 300 mm and 450 mm copper CMP process.

Haptic Feedback in a Telepresence System for Endoscopic Heart Surgery

The implementation of telemanipulator systems for cardiac surgery enabled heart surgeons to perform delicate minimally invasive procedures with high precision under stereoscopic view. At present, commercially available systems do not provide force-feedback or Cartesian control for the operating surgeon. The lack of haptic feedback may cause damage to tissue and can cause breaks of suture material. In addition, minimally invasive procedures are very tiring for the surgeon due to the need for visual compensation for the missing force feedback. While a lack of Cartesian control of the end effectors is acceptable for surgeons (because every movement is visually supervised), it prevents research on partial automation. In order to improve this situation, we have built an experimental telemanipulator for endoscopic surgery that provides both force-feedback (in order to improve the feeling of immersion) and Cartesian control as a prerequisite for automation. In this article, we focus on the inclusion of force feedback and its evaluation. We completed our first bimanual system in early 2003 (EndoPAR Endoscopic Partial Autonomous Robot). Each robot arm consists of a standard robot and a surgical instrument, hence providing eight DOF that enable free manipulation via trocar kinematics. Based on the experience with this system, we introduced an improved version in early 2005. The new ARAMIS system (Autonomous Robot Assisted Minimally Invasive Surgery) has four multi-purpose robotic arms mounted on a gantry above the working space. Again, the arms are controlled by two force-feedback devices, and 3D vision is provided. In addition, all surgical instruments have been equipped with strain gauge force sensors that can measure forces along all translational directions of the instrument's shaft. Force-feedback of this system was evaluated in a scenario of robotic heart surgery, which offers an impression very similar to the standard, open procedures with high immersion. It enables the surgeon to palpate arteriosclerosis, to tie surgical knots with real suture material, and to feel the rupture of suture material. Therefore, the hypothesis that haptic feedback in the form of sensory substitution facilitates performance of surgical tasks was evaluated on the experimental platform described in the article (on the EndoPAR version). In addition, a further hypothesis was explored: The high fatigue of surgeons during and after robotic operations may be caused by visual compensation due to the lack of force-feedback (Thompson, J., Ottensmeier, M., & Sheridan, T. 1999. Human Factors in Telesurgery, Telmed Journal, 5 (2) 129–137.).

The best angle for dragging a box

A combined theoretical-experimental exercise is described in which students predict how the coefficient of static friction and the direction of application of a force affect the minimum force needed to start an object sliding over a horizontal surface. This prediction is verified either by hanging weights on a cord or by pulling with a strain-gauge force sensor.

Towards a force-controlled microgripper for assembling biomedicalmicrodevices

This paper presents recent results on the development and control ofa microgripper based on flexure joints, fabricated by LIGA and instrumentedwith semiconductor strain-gauge force sensors. The microgripper is theend-effector of a workstation developed to grasp and manipulate tiny objectssuch as the components of a typical biomedical microdevice.The development of the force control in the microgripper is of fundamentalimportance in order to achieve the dexterity and sensing capabilities requiredto perform assembly tasks for biomedical microdevices.As a step towards the definition of the force control strategy, systemidentification techniques have been used to model the microgripper. Resultsindicate that a proportional integral (PI) controller could be used to assure,at the same time, closed-loop stability of the system, and a bandwidthsuitable for the intended applications. The force control is based onstrain-gauge sensors which have been integrated in the microgripper andexperimentally characterized. Sensor response in the idling condition andduring grasp showed that they can provide useful information for force controlof the microgripper.

Canine latissimus dorsi muscle: an apparatus for isometric force measurements.

This paper describes a device used to measure the isometric forces generated during electrical stimulation of the canine latissimus dorsi muscle in vivo with a preserved neurovascular supply. This device uses 2 strain gauge force sensors linked to a movable alignment frame to which the muscle is attached. The muscle length is controlled by the application of known weights to the system. The device has a frequency of response of 17.5 Hz and compliance of approximately 0.1 mm N(-1), and its experimental performance was tested in the anesthetized mongrel dog.

Robot gripper control system using PVDF piezoelectric sensors

A novel robot gripper control system is presented that uses PVDF (polyvinylidene fluoride) piezoelectric sensors to damp exerted force actively. By monitoring the current developed by the PVDF sensor, an output proportional to the rate of change of the force exerted by the gripper is obtained. The signals from the PVDF sensor and strain-gauge force sensor are arranged in a proportional and derivative control system for the control of force. The control system was tested on an instrumented Rhino XR-1 manipulator hand. The capabilities of the control system are analyzed and are verified experimentally. The results for this particular gripper indicate that the additional sensory feedback can decrease the force step response rise time by 88% while maintaining a monotonic zero-overshoot response. The inclusion of the rate feedback increases the damping ratio of the dominant poles while maintaining the step response rise time.

Strain-gauge force sensor

Strain-gauge force sensor