Patent Application
20160136822
The subject matter herein generally relates to object handling.
When robotic hands lack any type of touch feedback, mishandling or fracture of the object they are supposed to pick up can occur. Therefore, tactile sensors are used for robotic manipulation and to sense interactions with robotic finger interfaces. These sensors should be capable of detecting when a robotic finger comes in contact with any type of object at any angle. This feature is very important because in general a robot will not have any prior model of the object and must use its hands to contact and learn about the object.
Current robotic fingers use tactile sensors to detect contact, the sensor have a contact-sensitive shape. The sensors also need to deal with this condition by either detecting saturation contact or having a large operating range. After the initial contact with an object, the fingers of a robot exert high forces to handle objects. Many attempts have been made to implement tactile sensing in robots. There are many technologies used to build sensor arrays, for example, a compliant convex surface disposed above a sensor array, and the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector. In another example, most sensors are essentially a flexible elastic skin, coupled with a method of measuring the deformation caused by the applied force. However, either the structure of the sensor arrays or the flexible elastic skin is complicated and may be expensive.
Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.
A robotic hand includes an approximation of a human palm and plurality of fingers. Each robotic finger includes a proximal phalange and a distal phalange, wherein the distal phalange have a finger tip positioned on the end portion of the robotic finger. The robotic hand further includes a controller configured to actuate the plurality of robotic fingers and to detect contact by at least one of the plurality of robotic fingers with an object by sensing changes in the compliant torque of at least one of the plurality of robotic fingers. The controller is further configured to cause at least one of the actuators of the plurality of robotic fingers to exert a compliant torque on at least one of the plurality of robotic fingers to exert a force on the object.
An example embodiment of the present disclosure is described in relation to a structure of robotic finger. The robotic fingers exert a force on an object which is sensed by tactile sensor that is positioned on the fingertip of the robotic finger.
The fingertip 102 is a body with a first end and a second end, the first end of the body is movably connectable to the robotically controlled extension allowing the section to be robotically controlled. The second end has a contact portion, the contact portion inside of the robotic finger 100, the contact portion of the second end of the body includes a flexible surface and the tactile sensor 104 is integrated with the flexible surface of the second end of the body. In another word, the contact portion such as a finger pulp 1022 mimics the size and shape of the human equivalent, and the tactile sensor 104 is integrated with the surface of the finger pulp 1022. The finger pulp 1022 is made of flexible material, such as but not limited to rubber. The tactile sensor 104 is connectable to the robotic controller (not shown) to control movement of the extension, the tactile sensor 104 configured to form a detecting area 1040 that is convex in shape on the flexible surface of the contact portion of the second end of the body. That is, the detecting area 1040 is convex in shape on the surface of the finger pulp 1022. The shape of the detecting area 1040 (in a plane view) is circular.
The tactile sensor 104 feeds back the perpendicular pressure to the controller, and then the controller can maneuver the robotic fingers 100 to accurately control grip force. The tactile sensor 104 further can have a rough surface or a microstructure (not shown) on the surface of the detecting area 1040, thus when the detecting area 1040 contacts the object A, the rough surface or the microstructure touches the object A surface to increase friction between the robotic finger 100 and the object A, for more stably holding onto the object A. The microstructure of the rough surface is concentric circles or fingerprint ridges. In addition, the tactile sensor 104 may be other type of sensor, for example a heat sensor. Thus when the tactile sensor 104 is a temperature sensor, useful information as to human body temperature, pulse, and heartbeat can be obtained in medical care application.
The structure of the tactile sensor 104 is ultra-thin and flexible; it is easily integrated into the fingertip 102 of robotic finger 100 with ease of production and low cost. The detecting area 1040 of the tactile sensor 104 can measure pressure in a plane which is perpendicular to two mating or virtually mating surfaces accurately and feed information back to the controller, control of the grip force of the robotic finger 100 is improved.
The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a robotic finger. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201410656337.8 | Nov 2014 | CN | national |
