A Sensor Based on a Spherical Parallel Mechanism for the Measurement of Fluid Velocity: Experimental Development

Abstract

In this paper, an experimental demonstration was developed, to measure the velocity of a fluid by using a sensor based on the spherical parallel mechanism with three degrees-of-freedom. This sensor transforms the kinetic energy of the fluid into potential energy by deforming the parallel mechanism. This deformation is due to the impact of the fluid on a sphere attached to the platform of the parallel mechanism. Through the acquisition of data from an inertial measurement unit in the sphere, an algorithm calculates the velocity and direction of the fluid. The mathematic model and algorithm of the velocity measurement was developed in a previous article. This paper built and tested the sensor with the objective of demonstrating the theoretical basis for the sensor. The experiment is based on the underwater movement of the sensor in a linear way along a rail. The velocity that is measured by the linear encoder is equal to the fluid's relative velocity that is measured by the sensor. The measurements taken by the encoder and the sensor were compared in three experiments. The results show that the two measurements were similar, demonstrating that the sensor can accurately measure the velocity of the fluid.

Investigation on a flow transducer using modified force sensing technique

“…Thus due to the flow of the fluid through the semicircular pipeline section with an average velocity v, the net horizontal component of the centrifugal force is zero. Hence the net centrifugal force acting on the semicircular pipeline section acts along the vertically downward direction and is given by the above (5).…”

“…So the research works on the development of new or modified flow measurement techniques with various improvements are still being reported in the literature by various research groups. Portilla et al [5] have developed a fluid velocity sensor consisting of a sphere attached with a parallel mechanism. In this system, the deformation of the parallel mechanism by the impact force of the flowing fluid on the sphere is sensed by a linear encoder type sensor.…”

“…Portilla et al . [5] have developed a fluid velocity sensor consisting of a sphere attached with a parallel mechanism. In this system, the deformation of the parallel mechanism by the impact force of the flowing fluid on the sphere is sensed by a linear encoder type sensor.…”

Dynamic Walking of a Legged Robot in Underwater Environments

“…Finally, the velocity of the fluid is calculated by the hydrodynamic Equation of the drag force. The theoretical explanation of this sensor is shown in the paper by the authors of [13] and the demonstration experiment is shown in the paper by the authors of [14].…”

“…For the demonstration of the proposed concepts, a prototype of a planar bipedal robot was developed with a hydraulic actuator and a mechanical sensor that measures the velocity of the fluid relative to the centre of mass of the robot. The theoretical foundation and experimental validation of the sensor are found in [13,14].…”