MULTI POINT, HIGH SENSITIVE TACTILE SENSING MODULE FOR ROBOTS AND DEVICES
The features of the system are: fiber optic cables (instead of human sensory receptor) and low cost CMOS or CCD image sensor (which can be found in a conventional webcam, camcorder, digital camera etc.) are used by pairing each pixel of the image sensor with corresponding fiber optic cable, which is assured to transfer all light beams to the processor on a single photo frame where the coordinates and the level of displacements are detected precisely by the aid of image processing techniques, in order to provide tactile sensing. The system can work with a computer or it can work individually with an electronically circuit that contains an independent processor.
1. Technical Field
The disclosure is related to sensors (feedback mechanisms) of robotics and devices.
2. Background Information
It is well known that automation mimics the human body. It is observed that the computation systems for the data acquisition from sensors are basically a simple copy of human brain as well as the sensors are the simple copies of the receptors of the human body. It is clear that the automation systems with less than a hundred years of past, have a long way in order to reach the capability of human body with the experience of hundreds thousands years of evolution.
“Tactile Sensing”, which is the topic of the disclosure,—with current technology—is frequently limited to sense an approaching metal or a material that the sensor is sensitive and inform that to main processor by using proximity sensors. As the data which is transmitted by these sensors include only “true” or “false” and they are lack of leveled information, and they are also bulky (few millimeters diameter), these sensors are not efficient for multiple point applications.
Even for most developed humanoids, the technique that is currently being used is very expensive force/torque sensors, that are located on the joints. These sensors measure the contact pressure when an obstacle is in the way of the limb or when an object has been grasped. There exist one or more sensors and data acquisition systems for each limb (arm-elbow joint, fingers, etc.) in this detection/sensation method which costs too much.
For the application when pressure sensors are used the geometrical dimension becomes the issue, again. Even if the geometrical problem is relatively solved than again the transmission of the data to the main processor becomes an issue. Expensive data acquisition cards or microcontrollers are being used for current applications, but when the input numbers reach the level of hundred numbers; these inputs become a constraint/limiting factor. Human body that has been trying to be mimicked includes hundreds of thousands even millions of receptors in the fingertip, as it is known. And human brain processes all the data that are coming from these receptors very fast.
The most recent and similar robotic tactile sensing patent that is related is Koyoma and et. als.'s with number US20110067504A1, which is submitted at May 29, 2008 and published at Mar. 24, 2011. Optocouplers are suggested for tactile sensing, but because of the dimensions of these optocouplers for each fingertip of the humanoid, a single sensor is proposed. It is suggested that by placing one sensor for 5 millimeters with a matrix format will increase the quantity which means 9 sensors for 1 centimeter.
All related and similar patents have the common issues like, low sensitivity, low quantity sensor per one centimeter square (limited to number tens) and the constraints on the data input numbers.
BRIEF SUMMARYIt is intended to increase the number of the quantity of the sensors per one centimeter square up to more than one million. It is also aimed to measure all of these millions of points' per one centimeter displacements each and proses the data fast by avoiding high costs.
Every part in the figures are numbered and explained below.
- 1) Infrared (or normal) light source
- 2) Infrared (or normal) light receiver.
- 3) Reflecting light from the obstacle
- 4) The distance between the light source/receiver and the obstacle.
- 5) Light reflecting obstacle and the meantime the separator of the system from the surrounding environment.
- 6) Surrounding environment.
- 7) Fiber optic cables that carry the light from the source that is placed far from the measuring area.
- 8) Fiber optic cable that carries the light to the receiver that is placed far from the measuring area.
- 9) Webcam or a similar digital camcorder or digital camera sensor (CMOS, CCD etc.)
- 10) Light capturing pixels meant to analyze connected light where each works individually.
- 11) Light Source (Sum of more than one light source.)
- 12) Elastic Material
- 13) Rigid area; where fiber optic cables' tips are located and united with the elastic area, and which prevents the unwanted level of penetration.
- 14) Shape deformation when an object is penetrated through the elastic area.
- 15) Bunch of cables consist of number 7 and 8 fiber optic cables.
- 16) The image that is composed by the sensors corresponding to the area where there is no deformation.
- 17) The image that is composed by the sensors corresponding to the area where there is deformation.
- 18) The connection areas that form groups, depending on the different measurement areas through the fiber optic cables that carry the light.
- 19) Optical system that makes the light beams closer. (Each material that is used in the system is infrared conductive)
- 20) Intensive bunch of beams of light (closer to each other).
Optocouplers are one of the components that are frequently used in circuits of encoders and in other types of electronically circuits to provide electrical isolation. Optocouplers include a normal or infrared light source (1) and a light receptor (2) (
Not every receptor (1) requires a corresponding light source (11); however each measurement point requires a corresponding receptor (2). Despite the fact that fiber optic cables (7) (8) solve the dimensional issues at the reception area, it results in an issue of an overall system dimension's being huge. But the real problem is acquiring and processing of millions of data rather than the dimensional issue. A voltmeter with one channel can only read one, a two channeled oscilloscope can read two, and a 32 analogues input data acquisition card can read 32 data. Thus, any of these options are neither cost efficient nor close to a convenient answer to the requirement of reading all the data. With this system, CMOS or CCD sensor which can be found in a conventional webcam or a similar camcorder or a digital camera is utilized to overcome above mentioned problem. Main advantage of these kinds of sensors (9) is the feature of containing millions of sensory pixels (10) depending on the resolution of the product. (
Each sensory pixel (10) is able to detect 16.4 million colors in standard usage; therefore it is possible to measure the displacement precisely by the variation of light. In
For instance if the penetration area is too small and the corresponding light is close to white (the intensity of light is too high) it will be understood that a needle type of a sharp body has sunk in. If so, the robot or the device will act like what it is programmed to. This will be a reflex program, meaning that the area of penetration can be drawn back.
Meanwhile if the robot or the device is needed for more heavy duties or does not need to be as sensitive as human skin, the elastic material (12) can be chosen with a less elasticity feature. Thus, the system will have a similar tactile sensing for bigger forces. After a calibration for the new material's elasticity module and light conductivity for the calculations, the new system will work.
It is known that the commercial thermal cameras are infrared cameras which measure the temperature. The color becomes brighter and whiter if the temperature increases when recording with infrared cameras. The proposed system will also measure any heat source near the detection field. It will help to protect the device or robot form high temperature because the measurement will be close to white just like sharp body penetration effect.
It is mentioned before that a sensor obtained from HD webcam contains more than two millions of pixels. A single component is able to contain more than twenty millions of pixels if a high definition digital camera is used, instead. One fingertip or any other part of human body can intensify that much of receptors. For this reason incoming fiber optic cables (8) from different sensory organs are located in virtual different areas (18) of the image sensor (9), therefore with one image sensor more than one sensory organ can be measured.
Because of the variety of the used products and fiber optic cable (15) diameters and pixel (10) dimensions do not match with each other and a problem can arises. In order to prevent this issue beams/rays of light can be converged (20) to each other as in
The system can work with nearly every personal computer as well as industrial computers by connecting sensors like CMOS, CCD, etc. through an electronically circuit specialized for this system to the main processor of the device or robot.
INDUSTRIAL APPLICATIONThis system can answer to a lot of industrial fields that works with automation systems because the number of receptors per unit area is dramatically increased and the pressure and force values can be obtained fast.
Some outstanding application areas; robotic sensing—realizing the tactile sensing of humanoids; medical—with more receptors a better feeling of touching to the patient for remote operations (haptic); increase the sensing abilities of landmine scanning and bomb disposal robots accordingly decreasing the chance of failure and adding the temperature measurement to tactile sensing in case needed.
Claims
1.-6. (canceled)
7. A multi-point, high sensitive tactile sensing module for robots and devices, comprising: an elastic material, which is covered with a layer providing light reflection, wherein said layer simulates human skin; a CMOS or CCD image sensor; at least one light source; a plurality of fiber optic cables, ends of which are separated from a surrounding environment via said layer by being located under the layer and other ends of which are in connection with said light source, wherein said fiber optic cables carry light beams from the light source to said layer; another plurality of fiber optic cables, ends of which are separated from a surrounding environment via said layer by being located and being directed towards the layer and other ends of which are in connection with said image sensor so that each fiber optic cable is paired with one pixel of the image sensor, wherein light beams reflected from the layer are transferred to the image sensor by said fiber optic cables; a processor which calculates every individual force applied to the layer according to light intensity changes of each pixel connected with a fiber cable, of a photo frame generated by the image sensor in response to the displacement of the layer by using image processing techniques.
8. A multi-point, high sensitive tactile sensing module according to claim 7, wherein said elastic material has same elasticity of human flesh.
9. A multi-point, high sensitive tactile sensing module according to claim 7, wherein elasticity of said elastic material is less than elasticity of human flesh.
10. A multi-point, high sensitive tactile sensing module according to claim 7 wherein said light source is a normal/regular light source.
11. A multi-point, high sensitive tactile sensing module according to claim 7 wherein said light source is an infrared light source so as to detect temperature.
12. A multi-point, high sensitive tactile sensing module according to claim 7 wherein deformation of the elastic material is proportional to the applied force.
13. A multi-point, high sensitive tactile sensing module according to claim 7 further comprising an optical system that converges light beams transferred to the pixels of the image sensor.
Type: Application
Filed: Oct 31, 2012
Publication Date: Apr 23, 2015
Inventor: Utku BUYUKSAHIN
Application Number: 14/391,613
International Classification: G01L 5/22 (20060101); G01L 1/24 (20060101);