Force Estimation System Research Articles

Attractive Force Estimation of a Magnetic Adsorption Unit for Inspection UAVs

This paper presents an attractive force estimation system and an automatic activation system for an electropermanent magnet (EPM) for an inspection UAV. Adsorption to infrastructures for inspection at a distance is extremely difficult to perform safely because the operator cannot detect the state of adsorption of the drone equipped with a magnetic adsorption device. Therefore, in this paper, we clarify the relationship between the magnetic flux density and attractive force of the EPM through experiments, and develop an estimation algorithm for the attractive force based on the results. An automatic activation system, using the induced voltage in the coil when the EPM approaches the magnetic substance, is developed and mounted on a quadrotor for a flight experiment along with the estimation system for the attractive force. The developed system is verified using flight and adsorption experiments on the quadrotor.

Development of Power Add-on Unit with Sensorless Force Estimation and Slope-assistance System

Development of Power Add-on Unit with Sensorless Force Estimation and Slope-assistance System

손가락 동작과 힘 추정 시스템

This presents a motion and force estimation system of human fingers by using an Electromyography (EMG) sensor module and a data glove system to be proposed in this paper. Both EMG sensor module and data glove system are developed in such a way to minimize the number of hardware filters in acquiring the signals as well as to reduce their sizes for the wearable. Since the onset of EMG precedes the onset of actual finger movement by dozens to hundreds milliseconds, we show that it is possible to predict the pattern of finger movement before actual movement by using the suggested system. Also, we are to suggest how to estimate the grasping force of hand based on the relationship between RMS taken EMG signal and the applied load. Finally we show the effectiveness of the suggested estimation system through several experiments.

An EMG-based muscle force monitoring system

Information about muscle forces helps us to understand human movements more completely. Recently, studies on estimating muscle forces in real-time have been directed forward; however, the previous studies have some limitations in terms of using a three-dimensional (3D) motion capture system to obtain human movements. In the present study, an electromyography (EMG)-based real-time muscle force estimation system, which is available for a variety of potential applications, was introduced with electrogoniometers. A pilot study was conducted by performing 3D motion analysis on ten subjects during sit-to-stand movement. EMG measurements were simultaneously performed on gastrocnemius medialis and tibialis anterior. To evaluate the developed system, the results from the developed system were compared with those from widely used commercially available off-line simulation software including a musculoskeletal model. Results showed that good correlation coefficients between muscle forces from the developed system and the off-line simulation were observed in gastrocnemius medialis (r = 0.718, p < 0.01) and tibialis anterior (r = 0.821, p < 0.01). However, muscle lengths and muscle forces were obtained with a maximum delay of about 100 ms. Further studies would be required to solve the delay limitation. The developed system yielded promising results, suggesting that it can be potentially used for the real-time diagnosis of muscle or interpretation of movements.

Development of an Automated Wireless Tension Force Estimation System for Cable-stayed Bridges

Cable-supported bridges rely on the use of steel cables to support the bridge deck and load on it. Cable tension forces are monitored during construction to assist the alignment of cables and to ensure no cables are overloaded. Given that the cables are critical load carrying elements, it is prudent to routinely monitor the levels of cable tensions during operation. With current measurement methods being costly and labor-intensive, this article proposes an automated and low-cost wireless sensor system for continuous monitoring of the cable tension based on the vibration signature of the cable. A vibration-based tension force estimation method using a peak picking algorithm is explored by embedding it in the computational core of a wireless sensor. Welch’s method to average Fourier spectra from the segments of a long time history signal is employed to remove the non-stationarity of a short-duration acceleration record, which is a limit of the memory-constrained wireless sensor. A series of laboratory tests are conducted on a slender braided steel cable with a variety of cable sags and tension forces. Excellent agreements have been found between the actual tensions and those estimated by the present wireless system.

723 ウエアラブルな床反力推定システムの開発(機械力学・計測制御IV)

723 ウエアラブルな床反力推定システムの開発(機械力学・計測制御IV)

Hybrid Position and Force Control Without Force Sensor

Generally, hybrid control is realized by sensor signal feedback of position and force. However, some robot manipulators do not have a force sensor due to the environment. Moreover, a precise force sensor is very expensive. In order to overcome these problems, we propose the estimation system of reaction force without using a force sensor. This system consists of the torque observer and the inverse dynamics calculation. Using both this force estimation system and &lt;I&gt;H&lt;/I&gt;∞ acceleration controller which is based on &lt;I&gt;H&lt;/I&gt;∞ control theory, it takes into account the frequency characteristics of both sensor noise effect and disturbance rejection. The experimental results in this paper illustrate the fine hybrid control of the three tested degrees-of-freedom DD robot manipulator without force sensor.

Hybrid Control of Robot Manipulator without Force Sensor

This paper proposes the new hybrid control of force and position without force sensor. The proposed hybrid control system is designed by both H∞ acceleration controller and the force estimation system. H∞ accleration controller realizes a fine and robust motioncontrol. The reaction force estimation system consists of the torque observe and tip inverse dynamics calculation, and its estimated value is fed to the force control system the experimental results in this paper illustrate the fine hybrid control of the tested three-degrees-of-freedom DD robot manipulator without force sensor