Multi-axis Force Sensor Research Articles

Mechanical Characteristic and Design Principle of Underwater Force Sensor Based on Pressure Balance of Bladder

In order to balance the hydraulic pressure acted on the multi-axis force sensor of underwater robot,the long-shell theory is selected to research the distortion of bladder used in the sensor and amendment of this theory is carried out based on the mechanics analysis of the long and the short thin shells. An iteration algorithm used to calculate the pressure difference between in and out of the sensor is put forward,which applies the pressure balance method of bladder. Formulas of pressure difference,additional axial force,etc,in the pressure balance method of bladder are educed. The relative factors especially the pressure difference which affects the extra axial force acting on the sensor are analyzed and the characteristics of the pressure balance method of bladder,namely being competent for high pressure balance and possessing a wonderful ability to balance the slight pressure under high pressure. The criterions in designing the structure of the underwater force sensor of bladder are brought forward,namely,compact structure,small length-diameter ratio,large pressure balance diaphragm,minimal wall thickness and little oil inside the structure.

432 静電容量型多軸力覚センサを用いたメス操作時の反力評価(OS8-1:生活支援と福祉工学(1),OS8:生活支援と福祉工学)

432 静電容量型多軸力覚センサを用いたメス操作時の反力評価(OS8-1:生活支援と福祉工学(1),OS8:生活支援と福祉工学)

Topology Optimization of Multi-Axis Force Transducer Structures Based on Singular Value Decomposition

Multi-axis force sensors are extensively utilized in engineering fields, for example in automotive development, where 6-axis force transducers are used to measure force components applied to wheels, and as sensors in robotic manipulators. This paper describes a new structural optimization method for multi-axis force sensor structures considering the accuracy of force detection. First, we formulate homogenization design methods (HDM) in which continuous material distributions are assumed using a continuous interpolation function at each node. Next, we clarify the mechanical requirements and design specifications of the sensor structure, using a methodology based on singular value decomposition, and construct objective functions that aim to satisfy given design specifications. The sensitivities of the objective function with respect to the design variables are formulated using eigen values. Based on these formulations, an optimization algorithm is constructed using sequential linear programming (SLP). Finally, we examine the characteristics of the optimization formulations and the generated optimal configurations and confirm the usefulness of our proposed methodology for the optimization of multi-axis force sensor structures.

Investigation on calibration methods for multi-axis, linear and redundant force sensors

A new method for the calibration of multi-axis, linear and redundant force sensors is presented. This new procedure, named device hyperplane characterization method, is inspired by the shape from motion method for it reduces the burden represented by the need for a huge number of force measurements, typical using least-squares methods, in order to reject errors during the calibration procedure. The proposed technique is an application of the rank theorem and achieves good noise rejection without much time consumption focusing on sensor output measurements, and reducing the effect of disturbances operating the projection of raw output data on the hyperplane to which measurements are ideally compelled to belong in the case of redundant sensors.

Multiaxis Capacitive Force Sensor and its Measurement Principle Using Neural Networks

We propose a multiaxis capacitive force sensor consisting of one movable upper electrode on a plate and fixed lower electrodes on a substrate. The plate moves both vertically and horizontally when force is applied, and capacitance between upper and lower electrodes changes. This sensor uses the main electrical field between two directly facing electrodes and the fringe electrical field between diagonally opposed electrodes, making capacitance difficult to analyze. We simulated changes in nonlinear capacitance based on the upper electrode’s movement using the finite element method (FEM) and proved that capacitance is a function of the upper electrode’s displacement. We used a neural network to calculate the upper electrode’s displacement from capacitance. The neural network operates appropriately and calculated displacement error is within 0.5% of the full range. We proposed fabricating a practical force sensor consisting of planar capacitors making it compatible with surface micromachining and not requiring 3-D bulk micromachining, which simplifies fabrication, making it economical.

Contact Zone Force Profile and Machining Performance of Filamentary Brush1

Filamentary brushing tools are used in a wide range of surface finishing processes, such as deburring, edge radiusing, polishing, and surface decontamination applications. Moreover, these tools are easily adapted to automation because the filament tips, which perform the machining operation, readily conform to the workpart surface without the need for sophisticated control systems technology. However, little is known about the material removal mechanics of filamentary brushes and, therefore, trial-and-error experimentation is often necessary before the tool is implemented in a production environment. This uncertainty of performance can be traced to a lack of understanding of the actual forces that are generated within the contact zone, that is, along the interface of the filament tip and workpart surface. Although previous experimental research has focused on the overall (i.e., resultant) brush force exerted onto the workpart, no information exists in the literature regarding the variation of force within the contact zone. Such information is essential for understanding the material removal profile within the contact zone, and could provide valuable information regarding the most active machining site along the contact surface. In this paper, a novel experiment is proposed for evaluating the force profile of filament tip forces that are generated within the contact region of a brushed surface. A specially designed workpart fixture is constructed and used in conjunction with a multiaxis force sensor for measuring the detailed force variation within the contact zone. The experiment is conducted using a wire brush at several different rotational speeds, which enables one to ascertain the role of filament inertia in the material removal process. Findings are reported which suggest that a significantly enhanced material removal rate can be achieved at a selective location within the contact zone at moderately elevated spindle speeds.

自動感度可変型触覚センサ

This paper proposes a tactile sensor capable of automatically adjusting its sensitivity, depending upon the contact information. Suppose a strain gauge based sensor, such as multi-axis force sensor and tactile sensor. One big issue for those sensors is the signal saturation due to large input for a particular direction. The proposed sensor system can automatically avoid such a situation with combination of Automatic Gain Control (AGC) . The sensor is composed of a controller and an analyzer. The analyzer provides with the contact force and the controller tunes up the amplitude of each frequency. We discuss the basic design relue where two theorems are introduced for guaranteeing the working principle of the sensor with AGC. Experimental results are also shown for validating the basic idea of the proposed sensor.

A bulk microfabricated multi-axis capacitive cellular force sensor using transverse comb drives

This paper presents design, fabrication and calibration results for a novel 2-DOF capacitive force sensor capable of resolving forces up to 490 µN with a resolution of 0.01 µN in x, and up to 900 µN with a resolution of 0.24 µN in y. A simple fabrication process using deep reactive ion etching (DRIE) on silicon-on-insulator (SOI) wafers forms the 3D high aspect ratio structure. A transverse mode comb drive movement is used to greatly improve device sensitivity. Among other advantages of the developed process is a dice-free release of wafer structures, allowing fragile structures to be individually packaged. Notching or footing effects and bowing effects are well-known problems in DRIE on SOI wafers. Techniques to overcome notching and bowing effects using a PlasmaTherm SLR-770 etcher are presented that do not require hardware modifications. The application of the force sensor is for providing real-time force feedback during individual cell manipulation tasks.

Maximum Structural Error Propagation of Multi-Axis Force Sensors.

In multi-axis force sensors, compliance matrices representing structural behavior of internal sensor bodies play an important role in decoupled sensing and accuracy. Recently, error propagation through compliance matrices has been studied via approximation approach. However the upper bound of measured force error has not been known. In this paper, error propagation in force sensing is analyzed in a unified way when both strain measurement error and compliance matrix error exist, and the upper bound of the measured force error is derived (not approximately). The validity of the analysis is investigated through a numerical example.

Dynamic decoupling and compensating methods of multi-axis force sensors

Dynamic decoupling and compensating methods of multi-axis force sensors are proposed to solve simultaneously the dynamic coupling between axes and the slow dynamic response which are the two key problems in dynamic characterizing of the multi-axis force sensors and improve their dynamic quality. Four types of dynamic decoupling and compensating networks are shown, the design equations and procedures are presented, and the parameters of the networks are determined using a method based on a functional link artificial neural network (FLANN). The dynamic decoupling and compensating results for a wrist force sensor have proved the methods to be correct and effective.

A Practical Machining Condition Determination Strategy Using Multi-Axis Force Information

A manufacturing system which integrates a machining center with a multi-axis force sensor and realtime controller. CAD system and data-base was developed to realize high precision and high efficiency autonomously. To realize highly efficient machining while maintaining a stable cutting state, both a real-time adaptive control function and learning capability were implemented. Learning behavior was obtained by storing the actual state of the system in the form of an experimentally-determined stability lobe diagram. Efficient machining conditions, including the detailed tool path, were dynamically realized by regenerating the tool path periodically. Experimental results showed the effectiveness of the system.

A criterion for optimal design of multi-axis force sensors

This paper deals with the design of multi-axis force (also known as force/torque) sensors, as considered within the framework of optimal design theory. Optimal design procedures consists of finding the combination of design variables that extremizes some optimality criterion: provided a suitable mathematical formulation of the problem, solutions can be efficiently obtained through currently available numerical techniques. The principal goal of this paper is to identify a mathematical objective function, whose minimization corresponds to the optimization of sensor accuracy. The methodology employed is derived from linear algebra and analysis of numerical stability. An objective function which can be applied to a large class of sensor configurations is proposed. The problem of optimizing the number of basic transducers employed in a multi-component sensor is also addressed. Finally, applications of the proposed method to the design of a simple sensor as well as to the optimization of a novel, 6-axis miniaturized sensor are discussed.

多軸力センサとその応用

多軸力センサとその応用

A measurement of sliding resistance forces for various heads and disks by high-rigidity force sensor

The force on a head/disk interface has been measured using a novel multiaxis force sensor. The sensor has high resonance frequency (about 3 kHz) and high rigidity (about 1 N/ mu m) and can measure the sliding resistance force, F, accurately. The value of F for various heads and disks at various disk velocities (V) and its changes under repeated contact start-stop (CSS) are measured. Four components of F are identified. It is found that regardless of disk lubricant and head load, F/V is uniquely determined by disk roughness and head-fly-height. As CSS times increase, F becomes larger, and the head takes off at lower head-fly-height because the disk surface becomes smoother.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>